CN100485527C - Method for detecting imaging quality of photoetching machine - Google Patents

Abstract

The imaging quality detecting method for mask aligner includes the steps of preparation, lavel measurement, data processing, etc. While completing the in-situ detection of focal plane deviation, curvature of field, astigmatism and other axial image quality parameters, the present invention realizes the precise measurement aberration, magnification, translation, rotation and other radial image quality parameters. The present invention eliminates the dependence of the measurement precision of radial image quality parameters on the axial image quality correction, and can obtain the overall imaging quality parameters of mask aligner.

Description

The detection method of image forming quality of photoetching machine

Technical field

The present invention relates to litho machine, the detection method of particularly a kind of image forming quality of photoetching machine (being called for short " picture element ") is a kind of method of utilizing mirror image fine structure alignment mark (being called for short " mirror image FOCAL mark ") to measure litho machine picture element parameters such as the skew of photoetching mechanical coke face, image planes inclination, the curvature of field, astigmatism, magnification change, image planes translation, image planes rotation, distortion.

Background technology

The picture element parameter of litho machine can be divided into axial picture element parameter and hang down axle picture element parameter.Axially the picture element parameter comprises focal plane shift, the curvature of field, astigmatism, image planes inclination etc.The axle picture element parameter of hanging down comprises image planes translation, image planes rotation, distortion, magnification change etc.The image quality of litho machine directly influences Key Performance Indicators such as the CD homogeneity, alignment precision, depth of focus, exposure latitude of litho machine.Therefore the detection of litho machine picture element parameter is indispensable.

For accurately detecting the vertical axle of a litho machine picture element parameter, people such as Brink have proposed a kind of picture element detection technique based on silicon wafer exposure (referring to technology [1] formerly, M.A.van den Brink, C.G.M.de Mol, R.A.George, " Matching performance for multiple wafer steppers using an advanced metrologyprocedure ", Proc.SPIE Vol.921).This technology is to expose by silicon chip being moved to the optimal focal plane place, then the position of exposure figure is detected, thereby is calculated every vertical axle picture element parameter.But because the influence of axial image confrontation exposure figure positions such as out of focus, image planes inclination, even if out of focus in focal depth range, the errors in position measurement of exposure figure also will reach more than 10%.Therefore the shortcoming of this technology is that accuracy of detection depends critically upon the limited degree to axial picture element parameter such as out of focus, image planes inclination, and does not possess the ability that detects axial picture element, and it is additional to need other technology to do.

FOCAL (Focus calibration using alignment procedure) technology is that a kind of detection technique of utilizing mirror image to have the fine structure alignment mark to be used for the axial picture element parameter of high resolution litho machine is (referring to technology [2] formerly, Peter Dirksen, Jan E.Van Der Werf. " Method of repetitively imaging a mask pattem on asubstrate; and apparatus for performing the method ", Application No.: 5,674,650).This technology is carried out optical alignment to the FOCAL figure of exposure on silicon chip, and the alignment offset amount information of utilizing detection to obtain is carried out series of computation, thereby obtains axially picture element parameter such as best image planes, image planes inclination, the curvature of field, astigmatism with degree of precision.Regrettably this technology does not relate to the detection of the axle picture element parameter of hanging down.

Summary of the invention

The present invention overcomes the deficiency that above-mentioned prior art exists, and a kind of detection method of image forming quality of photoetching machine is provided.This method is not only finished axially picture element parameters in situ detection such as focal plane shift, the curvature of field, astigmatism, simultaneously can be to the accurate measurement of vertical axle such as distortion, magnification, translation, rotation picture element parameter, obtaining, with the dependence of the measuring accuracy of the axle picture element parameter of avoiding hanging down in the technology [1] formerly to axial picture element degree of correction to the comprehensive parameter of image forming quality of photoetching machine.Formerly technology [1] and the formerly middle incomplete problem of picture element parameter measurement of technology [2] have been solved.

Technical solution of the present invention is as follows:

A kind of detection method of image forming quality of photoetching machine is characterized in that this method comprises the following steps:

The first step: preliminary work:

1. initialization litho machine;

2. resist coating on the wafer and on to worktable;

3. preparation has the mask of a plurality of mirror image FOCAL marks, described mirror image FOCAL mark is meant and comprises four quadrants, the figure of each quadrant is made up of the thick lines and the hachure of some cycles, and first quartile is identical with the line orientations of second quadrant, and the rotation symmetry; Third quadrant identical with the four-quadrant line orientations but with first quartile, the perpendicular figure of the second quadrant line orientations; In mirror image FOCAL mark, the figure that first quartile and four-quadrant constitute is right FOCAL figure; The figure that second quadrant and third quadrant lines constitute is left FOCAL figure;

Second step: mark is measured:

1. will have on the mask of a plurality of mirror image FOCAL marks to mask platform;

2. selected several have the out of focus position of defocusing amount Δ f;

3. adjust illuminator, the lighting condition and the process conditions of exposure device are set;

4. control the motion of light source switch and worktable, mask platform, make the wafer that scribbles photoresist in selected a series of out of focus position exposure;

5. the wafer that is exposed carries out the back baking or develop in baking back, back;

6. utilize the reference grating of optical alignment system respectively two FOCAL figures about the mirror image FOCAL mark on the wafer to be aimed at, write down its aligned position coordinate, and be designated as P _L(x _L, y _L) and P _R(x _R, y _R);

The 3rd step: data processing:

The calculating of 1. horizontal aligument side-play amount: according to the theoretical position coordinate P of two FOCAL figure mark imagings in the exposure visual field about mirror image FOCAL mark _0L(x _0L, y _0L) and P _0R(x _0R, y _0R), and utilize their aligned position information to calculate the mirror image FOCAL mark left and right sides two-part horizontal aligument side-play amount AO respectively by (A) formula _LWith AO _R, in Cartesian coordinates: the horizontal aligument side-play amount of directions X is designated as Δ x _LWith Δ x _RThe horizontal aligument side-play amount of Y direction is designated as Δ y _LWith Δ y _R

$\left\{\begin{array}{c}\mathrm{\Δ}{x}_L=x_L-x_{0L}\\ \mathrm{\Δ}{y}_L=y_L-y_{0L}\\ \mathrm{\Δ}{x}_R=x_R-x_{0R}\\ \mathrm{\Δ}{y}_R=y_R-y_{0R}\end{array}\right.---\left(A\right)$

2. the axially calculating of the horizontal aligument side-play amount that causes of picture element: the horizontal aligument side-play amount AO that causes to picture element by horizontal aligument side-play amount reference axis ^v(Δ x ^vOr Δ y ^v), calculate with following formula,

${\mathrm{AO}}^v=2{\mathrm{AO}}_R^v=-2{\mathrm{AO}}_L^v={\mathrm{AO}}_R-{\mathrm{AO}}_L;---\left(B\right)$

3. axially align the calculating of side-play amount: the horizontal aligument side-play amount AO that causes according to axial picture element ^vDefocusing amount numerical value Δ f with corresponding utilizes least square method to carry out the biquadratic curve match, obtains (C) formula,

AO ^v＝a ₀+a ₁Δf+a ₂Δf ²+a ₃Δf ³+a ₄Δf ⁴ (C)

A wherein ₀, a ₁, a ₂, a ₃, a ₄Deng being the every coefficient of polynomial expression, utilize (C) formula to calculate alignment offset amount AO ^v(Δ x ^vOr Δ y ^v) when obtaining maximum value, numerical value Δ Zx, the Δ Zy of corresponding defocusing amount Δ f=Δ Zx (or Δ f=Δ Zy) are and axially align side-play amount;

4. axial picture element calculation of parameter: by axially aligning offset Zx, Δ Zy match (D) formula, thereby obtain axially picture element parameter such as focal plane shift, image planes inclination, the curvature of field and astigmatism:

$\left\{\begin{array}{c}(\mathrm{\&Delta;Zx}+\mathrm{\&Delta;Zy})/2=\mathrm{Zw}+\mathrm{Rx}\&CenterDot;x_0+\mathrm{Ry}\&CenterDot;{\mathrm{<figure-callout\; id="0"\; label="y"\; filenames="C200510025281E00221.png"\; state="\{\{state\}\}">y</figure-callout>}}_0+\mathrm{FC}\&CenterDot;({x_0}^2+{{\mathrm{<figure-callout\; id="0"\; label="y"\; filenames="C200510025281E00221.png"\; state="\{\{state\}\}">y</figure-callout>}}_0}^2)\\ \mathrm{average}(\mathrm{\&Delta;Zx}-\mathrm{\&Delta;Zy})=\mathrm{AS}\end{array}\right.---\left(D\right)$

Wherein Δ Zx, Δ Zy, x ₀, y ₀The axial offset of each FOCAL mark and be marked as the theoretical position coordinate of picture in the expression exposure visual field respectively, AS represent astigmatism, and on behalf of the curvature of field, Zw, FC represent optimal focal plane, Rx, Ry to represent respectively around X-axis with around the image planes inclination of Y-axis;

5. horizontal aligument side-play amount match: by horizontal aligument side-play amount AO _L(Δ x _LOr Δ y _L) and AO _R(Δ x _ROr Δ y _R) and corresponding out of focus numerical value Δ f, utilize least square method to carry out the biquadratic curve match respectively and obtain (E) formula,

$\left\{\begin{array}{c}\mathrm{\&Delta;}{x}_L={\mathrm{<figure-callout\; id="0"\; label="b"\; filenames="C200510025281E00221.png"\; state="\{\{state\}\}">b</figure-callout>}}_0+{\mathrm{<figure-callout\; id="1"\; label="b"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">b</figure-callout>}}_1\mathrm{\&Delta;f}+{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">b</figure-callout>}}_2\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">f</figure-callout>}}^2+{\mathrm{<figure-callout\; id="3"\; label="b"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">b</figure-callout>}}_3\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="3"\; label="f"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">f</figure-callout>}}^3+{\mathrm{<figure-callout\; id="4"\; label="b"\; filenames="C200510025281E00211.png,C200510025281E00221.png"\; state="\{\{state\}\}">b</figure-callout>}}_4\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="4"\; label="f"\; filenames="C200510025281E00211.png,C200510025281E00221.png"\; state="\{\{state\}\}">f</figure-callout>}}^4\\ \mathrm{\&Delta;}{x}_R={\mathrm{<figure-callout\; id="0"\; label="c"\; filenames="C200510025281E00221.png"\; state="\{\{state\}\}">c</figure-callout>}}_0+{\mathrm{<figure-callout\; id="1"\; label="c"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">c</figure-callout>}}_1\mathrm{\&Delta;f}+{\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">c</figure-callout>}}_2\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">f</figure-callout>}}^2+{\mathrm{<figure-callout\; id="3"\; label="c"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">c</figure-callout>}}_3\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="3"\; label="f"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">f</figure-callout>}}^3+{\mathrm{<figure-callout\; id="4"\; label="c"\; filenames="C200510025281E00211.png,C200510025281E00221.png"\; state="\{\{state\}\}">c</figure-callout>}}_4\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="4"\; label="f"\; filenames="C200510025281E00211.png,C200510025281E00221.png"\; state="\{\{state\}\}">f</figure-callout>}}^4\\ \mathrm{\&Delta;}{y}_L={\mathrm{<figure-callout\; id="0"\; label="d"\; filenames="C200510025281E00221.png"\; state="\{\{state\}\}">d</figure-callout>}}_0+{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">d</figure-callout>}}_1\mathrm{\&Delta;f}+{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">d</figure-callout>}}_2\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">f</figure-callout>}}^2+{\mathrm{<figure-callout\; id="3"\; label="d"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">d</figure-callout>}}_3\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="3"\; label="f"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">f</figure-callout>}}^3+{\mathrm{<figure-callout\; id="4"\; label="d"\; filenames="C200510025281E00211.png,C200510025281E00221.png"\; state="\{\{state\}\}">d</figure-callout>}}_4\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="4"\; label="f"\; filenames="C200510025281E00211.png,C200510025281E00221.png"\; state="\{\{state\}\}">f</figure-callout>}}^4\\ \mathrm{\&Delta;}{y}_R={\mathrm{<figure-callout\; id="0"\; label="e"\; filenames="C200510025281E00221.png"\; state="\{\{state\}\}">e</figure-callout>}}_0+{\mathrm{<figure-callout\; id="1"\; label="e"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">e</figure-callout>}}_1\mathrm{\&Delta;f}+{\mathrm{<figure-callout\; id="2"\; label="e"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">e</figure-callout>}}_2\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">f</figure-callout>}}^2+{\mathrm{<figure-callout\; id="3"\; label="e"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">e</figure-callout>}}_3\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="3"\; label="f"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">f</figure-callout>}}^3+{\mathrm{<figure-callout\; id="4"\; label="e"\; filenames="C200510025281E00211.png,C200510025281E00221.png"\; state="\{\{state\}\}">e</figure-callout>}}_4\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="4"\; label="f"\; filenames="C200510025281E00211.png,C200510025281E00221.png"\; state="\{\{state\}\}">f</figure-callout>}}^4\end{array}\right.;---\left(E\right)$

B in the formula ₀, b ₁, b ₂, b ₃, b ₄, c ₀, c ₁, c ₂, c ₃, c ₄, d ₀, d ₁, d ₂, d ₃, d ₄, e ₀, e ₁, e ₂, e ₃, e ₄Deng being the every coefficient of polynomial expression;

The calculating of the horizontal aligument side-play amount that the axle picture element that 6. hangs down causes: in (E) formula, calculate the horizontal aligument side-play amount AO when Δ f=Δ Zx or Δ f=Δ Zy _L(Δ x _LOr Δ y _L) and AO _R(Δ x _ROr Δ y _R), and calculate the horizontal aligument side-play amount AO that causes by the axle picture element that hangs down according to (F) formula ^h, i.e. Δ x ^hWith Δ y ^h:,

$\left\{\begin{array}{c}\mathrm{\&Delta;}{x}^h=\frac{\mathrm{\&Delta;}{x}_R+\mathrm{\&Delta;}{x}_{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">L</figure-callout>}}}{2}{|}_{\mathrm{\&Delta;f}=\mathrm{\&Delta;Zx}}\\ {\mathrm{\&Delta;y}}^h=\frac{\mathrm{\&Delta;}{y}_R+\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="2"\; label="y\; L"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">y</figure-callout>}}_L}{2}{|}_{\mathrm{\&Delta;f}=\mathrm{\&Delta;Zy}}\end{array}\right.;---\left(F\right)$

7. the axle picture element calculation of parameter of hanging down: the horizontal aligument side-play amount AO that causes by the axle picture element that hangs down ^hMatch (G) formula, thus vertical axle such as image planes translation, image planes rotation, magnification change amount, distortion picture element parameter obtained:

$\left\{\begin{array}{c}{\mathrm{\&Delta;x}}^h=\mathrm{dx}+x_0\mathrm{Mag}-{\mathrm{<figure-callout\; id="0"\; label="y"\; filenames="C200510025281E00221.png"\; state="\{\{state\}\}">y</figure-callout>}}_0\mathrm{\&phi;}+x_0{\mathrm{<figure-callout\; id="0"\; label="r"\; filenames="C200510025281E00221.png"\; state="\{\{state\}\}">r</figure-callout>}}_0^2{\mathrm{<figure-callout\; id="3"\; label="D"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">D</figure-callout>}}_3\\ {\mathrm{\&Delta;y}}^h=\mathrm{dy}+{\mathrm{<figure-callout\; id="0"\; label="y"\; filenames="C200510025281E00221.png"\; state="\{\{state\}\}">y</figure-callout>}}_0\mathrm{Mag}+x_0\mathrm{\&phi;}+y_0{\mathrm{<figure-callout\; id="0"\; label="r"\; filenames="C200510025281E00221.png"\; state="\{\{state\}\}">r</figure-callout>}}_0^2{D}_3\end{array}\right.---\left(G\right)$

Wherein: dx, dy be marked at X to Y to translation, Mag is the enlargement ratio variable quantity of exposure system, φ for the exposure visual field around the rotation of optical axis, D ₃Third-order distortion for exposure system.

Described lighting condition and process conditions are meant conditions such as coherence factor and numerical aperture size, photoresist type, photoresist thickness, back baking temperature, back baking time, development time.

The quantity that described mirror image FOCAL is marked on the mask should guarantee to have at least 5 mark in the exposure visual field with distribution, and is marked at evenly distribution in the visual field.

Described a series of out of focus position refers to the position of several defocusing amount Δs f optimal focal plane near, and its number should be greater than 5, and to have three out of focus positions at least be to be in the focal depth range of projection objective of imaging optical system of photoetching.

Described wafer refers to have the semiconductor material disk of monocrystalline or polycrystalline structure, is silicon chip, gallium arsenide disk or silicon dioxide disk.

Described exposure process comprises static stepping exposure and dynamic scan exposure.

Described optical alignment system is the optical alignment system that has with reference to optical grating construction, and its grating cycle and FOCAL mark structure cycle are complementary.

The described theoretical position that is marked as picture refers to that mirror image FOCAL mark is through becoming the position of desirable picture or paraxial rays imaging on the mask on wafer behind the projection objective.

Described defocusing amount Δ f is meant that current exposure plane is the distance of optimal focal plane with respect to reference planes, and its sign representative is with respect to the direction of optimal focal plane.

The curve of described match, its fitting result need be weighed with the multiple correlation factor, and the typical threshold of this multiple correlation factor is 0.7, when this factor during less than this threshold value, match again after the reply fitting data screens.

The present invention has the following advantages:

1, the line data fitting method of going forward side by side of exposing has been adopted in comparing with technology [1] formerly based on the image forming quality of photoetching machine detection method of mirror image FOCAL mark that the present invention proposes under different defocusing amounts, make the present invention when obtaining to hang down axle picture element parameter, its measuring accuracy does not rely on the limited degree to axial picture element, so measuring accuracy is higher than technology [1] formerly.

What 2, the present invention proposed compares with technology [2] formerly based on the image forming quality of photoetching machine detection method of mirror image FOCAL mark and technology [1] formerly, this technology has been owing to utilized mirror image FOCAL mark, thereby axially realized accurate measurement to vertical axle such as distortion, magnification, translation, rotation picture element parameter in the picture element parameter in situ detection finishing optimal focal plane, the curvature of field, astigmatism etc.Realize in test once the comprehensively function of measuring light etching system picture element parameter, simplified litho machine picture element testing process, saved the picture element detection time that 50% picture element detects cost and 50%.

Description of drawings

Fig. 1 the present invention is based on the structural drawing of the employed exposure device of image forming quality of photoetching machine detection method of mirror image FOCAL mark;

Fig. 2 the present invention is based on the testing process figure of mirror image FOCAL mark image forming quality of photoetching machine;

Mirror image FOCAL mark structure synoptic diagram among Fig. 3 the present invention;

Fig. 4 optical alignment system involved in the present invention is with reference to the structural representation of grating;

Mirror image FOCAL is marked at the distribution schematic diagram in the exposure visual field in Fig. 5 specific embodiment one;

The distribution schematic diagram of exposure field on silicon chip in Fig. 6 specific embodiment;

Mirror image FOCAL is marked at the distribution schematic diagram in the exposure visual field in Fig. 7 specific embodiment two;

Embodiment

The invention will be further described below in conjunction with embodiment and accompanying drawing, but should not limit protection scope of the present invention with this.

The detection method of image forming quality of photoetching machine of the present invention is based on the picture element parameter detection method of mirror image FOCAL mark, and its testing process enters mark measuring process (100) and data handling procedure (200) as shown in Figure 2 after preliminary work (00).The detection method of image forming quality of photoetching machine of the present invention comprises the following steps:

The first step: preliminary work 00:

1. initialization litho machine;

2. resist coating on the wafer 7 and on to worktable 8;

3. preparation has the mask 3 of a plurality of mirror image FOCAL marks, and each mirror image FOCAL mark comprises four quadrants, and the figure of each quadrant is made up of the thick lines and the hachure of some cycles, and first quartile is identical with the line orientations of second quadrant, and the rotation symmetry; Third quadrant is identical with the four-quadrant line orientations and mirror image is symmetrical, but it is perpendicular with the line orientations of first quartile, second quadrant, in this mirror image FOCAL mark, first quartile and four-quadrant constitute right FOCAL figure, and second quadrant and third quadrant lines constitute left FOCAL figure;

Second step: mark measures 100:

1. with on the described mask 3 with mirror image FOCAL mark to mask platform 4;

2. selected several have the out of focus position of defocusing amount Δ f;

3. adjust illuminator, the lighting condition and the process conditions 11 of exposure device are set;

4. the motion of Control work platform 8 and mask platform 4 makes the wafer 7 that scribbles photoresist in selected a series of out of focus position exposure 12;

5. the wafer 7 that is exposed carries out the back baking or baking back, back develops 13;

6. utilize the reference grating (as shown in Figure 4) of optical alignment system 6 respectively two FOCAL figures (shown in Figure 3) about the mirror image FOCAL mark on the wafer 7 to be aimed at 14, write down its aligned position coordinate, be designated as P _L(x _L, y _L) and P _R(x _R, y _R);

The 3rd step: data processing 200:

The calculating 21 of 1. horizontal aligument side-play amount: according to the nominal position P of two FOCAL figure imagings in the exposure visual field about mirror image FOCAL mark _0L(x _0L, y _0L) and P _0R(x _0R, y _0R), and utilize they and aligned position information to calculate the mirror image FOCAL mark left and right sides two-part horizontal aligument side-play amount AO respectively by (A) formula _LWith AO _R, in Cartesian coordinates: the horizontal aligument side-play amount of directions X is designated as Δ x _LWith Δ x _RThe horizontal aligument side-play amount of Y direction is designated as Δ y _LWith Δ y _R

$\left\{\begin{array}{c}\mathrm{\&Delta;}{x}_L=x_L-x_{0L}\\ \mathrm{\&Delta;}{y}_L=y_L-y_{0L}\\ \mathrm{\&Delta;}{x}_R=x_R-x_{0R}\\ \mathrm{\&Delta;}{y}_R=y_R-y_{0R}\end{array}\right.---\left(A\right)$

2. the axially calculating 22 of the horizontal aligument side-play amount that causes of picture element: the horizontal aligument side-play amount AO that causes to picture element by horizontal aligument side-play amount reference axis ^v(Δ x ^vOr Δ y ^v), calculate with following formula,

${\mathrm{AO}}^v=2{\mathrm{AO}}_R^v=-2{\mathrm{AO}}_L^v={\mathrm{AO}}_R-{\mathrm{AO}}_L;---\left(B\right)$

3. axially align the calculating 23 of side-play amount: the horizontal aligument side-play amount AO that causes according to axial picture element ^vDefocusing amount numerical value Δ f with corresponding utilizes least square method to carry out the biquadratic curve match, obtains (C) formula,

AO ^v＝a ₀+a ₁Δf+a ₂Δf ²+a ₃Δf ³+a ₄Δf ⁴ (C)

A wherein ₀, a ₁, a ₂, a ₃, a ₄Deng being the every coefficient of polynomial expression.(C) formula of utilization is calculated alignment offset amount AO ^v(Δ x ^vOr Δ y ^v) when obtaining maximum value, numerical value Δ Zx, the Δ Zy of corresponding defocusing amount Δ f=Δ Zx (or Δ f=Δ Zy) are and axially align side-play amount;

4. axial picture element calculation of parameter 24: by axially aligning offset Zx, Δ Zy match (D) formula, thereby obtain axially picture element parameter such as focal plane shift, image planes inclination, the curvature of field and astigmatism:

$\left\{\begin{array}{c}(\mathrm{\&Delta;Zx}+\mathrm{\&Delta;Zy})/2=\mathrm{Zw}+\mathrm{Rx}\&CenterDot;x_0+\mathrm{Ry}\&CenterDot;{\mathrm{<figure-callout\; id="0"\; label="y"\; filenames="C200510025281E00221.png"\; state="\{\{state\}\}">y</figure-callout>}}_0+\mathrm{FC}\&CenterDot;({x_0}^2+{{\mathrm{<figure-callout\; id="0"\; label="y"\; filenames="C200510025281E00221.png"\; state="\{\{state\}\}">y</figure-callout>}}_0}^2)\\ \mathrm{average}(\mathrm{\&Delta;Zx}-\mathrm{\&Delta;Zy})=\mathrm{AS}\end{array}\right.---\left(D\right)$

Wherein Δ Zx, Δ Zy, x ₀, y ₀The axial offset and the nominal coordinate of each FOCAL mark in the expression exposure visual field respectively, AS represent astigmatism, and on behalf of the curvature of field, Zw, FC represent optimal focal plane, Rx, Ry to represent respectively around X-axis with around the image planes inclination of Y-axis;

5. horizontal aligument side-play amount match 25: by horizontal aligument side-play amount AO _L=Δ x _LOr Δ y _LWith AO _R=Δ x _ROr Δ y _RAnd corresponding out of focus numerical value Δ f, utilize least square method to carry out the biquadratic curve match respectively and obtain (E) formula,

$\left\{\begin{array}{c}\mathrm{\&Delta;}{x}_L={\mathrm{<figure-callout\; id="0"\; label="b"\; filenames="C200510025281E00221.png"\; state="\{\{state\}\}">b</figure-callout>}}_0+{\mathrm{<figure-callout\; id="1"\; label="b"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">b</figure-callout>}}_1\mathrm{\&Delta;f}+{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">b</figure-callout>}}_2\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">f</figure-callout>}}^2+{\mathrm{<figure-callout\; id="3"\; label="b"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">b</figure-callout>}}_3\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="3"\; label="f"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">f</figure-callout>}}^3+{\mathrm{<figure-callout\; id="4"\; label="b"\; filenames="C200510025281E00211.png,C200510025281E00221.png"\; state="\{\{state\}\}">b</figure-callout>}}_4\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="4"\; label="f"\; filenames="C200510025281E00211.png,C200510025281E00221.png"\; state="\{\{state\}\}">f</figure-callout>}}^4\\ \mathrm{\&Delta;}{x}_R={\mathrm{<figure-callout\; id="0"\; label="c"\; filenames="C200510025281E00221.png"\; state="\{\{state\}\}">c</figure-callout>}}_0+{\mathrm{<figure-callout\; id="1"\; label="c"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">c</figure-callout>}}_1\mathrm{\&Delta;f}+{\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">c</figure-callout>}}_2\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">f</figure-callout>}}^2+{\mathrm{<figure-callout\; id="3"\; label="c"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">c</figure-callout>}}_3\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="3"\; label="f"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">f</figure-callout>}}^3+{\mathrm{<figure-callout\; id="4"\; label="c"\; filenames="C200510025281E00211.png,C200510025281E00221.png"\; state="\{\{state\}\}">c</figure-callout>}}_4\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="4"\; label="f"\; filenames="C200510025281E00211.png,C200510025281E00221.png"\; state="\{\{state\}\}">f</figure-callout>}}^4\\ \mathrm{\&Delta;}{y}_L={\mathrm{<figure-callout\; id="0"\; label="d"\; filenames="C200510025281E00221.png"\; state="\{\{state\}\}">d</figure-callout>}}_0+{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">d</figure-callout>}}_1\mathrm{\&Delta;f}+{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">d</figure-callout>}}_2\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">f</figure-callout>}}^2+{\mathrm{<figure-callout\; id="3"\; label="d"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">d</figure-callout>}}_3\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="3"\; label="f"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">f</figure-callout>}}^3+{\mathrm{<figure-callout\; id="4"\; label="d"\; filenames="C200510025281E00211.png,C200510025281E00221.png"\; state="\{\{state\}\}">d</figure-callout>}}_4\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="4"\; label="f"\; filenames="C200510025281E00211.png,C200510025281E00221.png"\; state="\{\{state\}\}">f</figure-callout>}}^4\\ \mathrm{\&Delta;}{y}_R={\mathrm{<figure-callout\; id="0"\; label="e"\; filenames="C200510025281E00221.png"\; state="\{\{state\}\}">e</figure-callout>}}_0+{\mathrm{<figure-callout\; id="1"\; label="e"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">e</figure-callout>}}_1\mathrm{\&Delta;f}+e_2\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">f</figure-callout>}}^2+{\mathrm{<figure-callout\; id="3"\; label="e"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">e</figure-callout>}}_3\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="3"\; label="f"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">f</figure-callout>}}^3+{\mathrm{<figure-callout\; id="4"\; label="e"\; filenames="C200510025281E00211.png,C200510025281E00221.png"\; state="\{\{state\}\}">e</figure-callout>}}_4\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="4"\; label="f"\; filenames="C200510025281E00211.png,C200510025281E00221.png"\; state="\{\{state\}\}">f</figure-callout>}}^4\end{array}\right.;---\left(E\right)$

B in the formula ₀, b ₁, b ₂, b ₃, b ₄, c ₀, c ₁, c ₂, c ₃, c ₄, d ₀, d ₁, d ₂, d ₃, d ₄, e ₀, e ₁, e ₂, e ₃, e ₄Deng being the every coefficient of polynomial expression;

The calculating 26 of the horizontal aligument side-play amount that the axle picture element that 6. hangs down causes: in the E formula, calculate the horizontal aligument side-play amount AO when Δ f=Δ Zx or Δ f=Δ Zy _L(Δ x _LOr Δ y _L) and AO _R(Δ x _ROr Δ y _R), and calculate the horizontal aligument side-play amount AO that causes by the axle picture element that hangs down according to (F) formula ^h, i.e. Δ x ^hWith Δ y ^h:,

$\left\{\begin{array}{c}\mathrm{\&Delta;}{x}^h=\frac{\mathrm{\&Delta;}{x}_R+\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="2"\; label="x\; L"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">x</figure-callout>}}_L}{2}{|}_{\mathrm{\&Delta;f}=\mathrm{\&Delta;Zx}}\\ {\mathrm{\&Delta;y}}^h=\frac{\mathrm{\&Delta;}{y}_R+\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="2"\; label="y\; L"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">y</figure-callout>}}_L}{2}{|}_{\mathrm{\&Delta;f}=\mathrm{\&Delta;Zy}}\end{array}\right.;---\left(F\right)$

7. the axle picture element that hangs down calculates 27: the horizontal aligument side-play amount AO that is caused by the axle picture element that hangs down ^hMatch (G) formula, thus vertical axle such as image planes translation, image planes rotation, magnification change amount, distortion picture element parameter obtained:

$\left\{\begin{array}{c}{\mathrm{\&Delta;x}}^h=\mathrm{dx}+x_0\mathrm{Mag}-{\mathrm{<figure-callout\; id="0"\; label="y"\; filenames="C200510025281E00221.png"\; state="\{\{state\}\}">y</figure-callout>}}_0\mathrm{\&phi;}+x_0{\mathrm{<figure-callout\; id="0"\; label="r"\; filenames="C200510025281E00221.png"\; state="\{\{state\}\}">r</figure-callout>}}_0^2{\mathrm{<figure-callout\; id="3"\; label="D"\; filenames="C200510025281E00181.png,C200510025281E00211.png"\; state="\{\{state\}\}">D</figure-callout>}}_3\\ {\mathrm{\&Delta;y}}^h=\mathrm{dy}+{\mathrm{<figure-callout\; id="0"\; label="y"\; filenames="C200510025281E00221.png"\; state="\{\{state\}\}">y</figure-callout>}}_0\mathrm{Mag}+x_0\mathrm{\&phi;}+y_0{\mathrm{<figure-callout\; id="0"\; label="r"\; filenames="C200510025281E00221.png"\; state="\{\{state\}\}">r</figure-callout>}}_0^2{D}_3\end{array}\right.---\left(G\right)$

Wherein: dx, dy be marked at X to Y to translation, Mag is the enlargement ratio variable quantity of exposure system, φ for the exposure visual field around the rotation of optical axis, D ₃Third-order distortion for exposure system.

Described lighting condition and process conditions are meant conditions such as coherence factor and numerical aperture size, photoresist type, photoresist thickness, back baking temperature, back baking time, development time.

The quantity that described mirror image FOCAL is marked on the mask should guarantee to have at least 5 mark in the exposure visual field with distribution, and is marked at evenly distribution in the visual field.

Described a series of out of focus position refers to the position of several defocusing amount Δs f optimal focal plane near, and its number should be greater than 5, and to have three out of focus positions at least be to be in the focal depth range of projection objective of imaging optical system of photoetching 5.

Described wafer 7 refers to have the semiconductor material disk of monocrystalline or polycrystalline structure, is silicon chip, gallium arsenide disk or silicon dioxide disk.

Described exposure process comprises static stepping exposure and dynamic scan exposure.

Described optical alignment system 6 is for having the optical alignment system with reference to optical grating construction, and its grating cycle and FOCAL mark structure cycle are complementary.

Described being marked as theoretical position refers to that mirror image FOCAL mark is through becoming the position of desirable picture or paraxial rays imaging on the mask 3 on wafer 7 behind the projection objective.

Described defocusing amount numerical value Δ f is meant that current exposure plane is the distance of optimal focal plane with respect to reference planes, and its sign representative is with respect to the direction of optimal focal plane.

The curve of described match or curved surface, its fitting result need be weighed with the multiple correlation factor, and the typical threshold of this multiple correlation factor is 0.7, when this factor during less than this threshold value, match again after the reply fitting data screens.

In the picture element testing process that the present invention proposes, formula (B) formula of the horizontal aligument side-play amount that reference axis causes to picture element is with to calculate the foundation that horizontal aligument side-play amount formula (F) formula that the axle picture element that hangs down causes sets up as follows: mirror image FOCAL is marked at different defocusing amounts place and is exposed on wafer, is measured the alignment offset amount AO of mirror image FOCAL mark on the wafer by optical alignment system _LWith AO _RIn etching system, cause mirror image FOCAL pattern alignment position and theoretical exposure position reason devious that two aspects are arranged.Owing to the axially influence of picture element such as out of focus, the curvature of field, astigmatism, the aligned position that causes is offset this part side-play amount AO thereby FOCAL mark fine structure live width changes on the one hand ^vExpression.On the other hand owing to the hang down skew of the aligned position that the axle picture element produces the influence of FOCAL mark exposure position of etching systems such as distortion, translation, rotation, this part side-play amount AO ^hExpression.Thus, mirror image FOCAL markers align side-play amount AO _LWith AO _RCan represent by (H) formula.

$\left\{\begin{array}{c}{\mathrm{AO}}_L={\mathrm{AO}}_L^v+{\mathrm{AO}}_L^h\\ {\mathrm{AO}}_R={\mathrm{AO}}_R^v+{\mathrm{AO}}_R^h\end{array}\right.,---\left(H\right)$

Notice that in mirror image FOCAL mark synoptic diagram shown in Figure 3 distance is very little between two parts figure of the left and right sides, representative value can think that the image-forming condition of two figures is basic identical less than 0.3mm for whole exposure visual field.Promptly the aligned position side-play amount that is caused by the axle picture element that hangs down is equal substantially, ${\mathrm{AO}}_L^h\&ap;{\mathrm{AO}}_R^h.$ Influence the variation of fine structure live width and the big or small approximately equal of the alignment offset amount that causes by axial picture element.But because the mirror image symmetrical feature of fine structure position causes the direction of side-play amount opposite, promptly ${\mathrm{AO}}_L^v\&ap;-{\mathrm{AO}}_R^v.$ Utilize above-mentioned two approximate conditions, with two equation additions in (H) formula or subtract each other and to obtain (B) formula and (F) formula.Wherein (F) formula adopts the form performance of coordinate.(B) formula and (F) establishment of formula among the present invention so far have been described.

Embodiment 1:

Fig. 2 is the testing process of the etching system image quality parameter of the present invention's proposition.As shown in Figure 1 and Figure 2, be coated with JSR M206Y type photoresist on silicon chip 7, glue is thick to be 490nm, and with silicon chip last slice to work stage 8.The exposure device lighting condition is set: traditional lighting, NA are 0.57, partial coherence factor is 0.7.The mask R adjustment of the printing plate that will have mirror image FOCAL mark is on mask platform RS.The exposure visual field is 26mm x 8mm, and the distribution of exposure area internal labeling as shown in Figure 5 on the silicon chip.Control photo-etching machine work-piece platform movement position adopts the static exposure mode that mirror image FOCAL on the mask is marked under the different defocusing amounts and exposes on silicon chip.The out of focus scope from-0.9um to 0.9um, stepping 0.12um, totally 16 exposure field.The silicon chip W that is exposed utilizes that optical alignment system AS aims at and write down aligned position information to mirror image FOCAL mark on the silicon chip in the exposure device after later baking is developed, alignment system reference light grid cycle is 16um.The temperature of back baking is 120 ℃, afterwards the baking time is that 90s, development time are 60s; Utilize the mirror image FOCAL markers align positional information that is obtained, according to the described computation process of step of the present invention, the horizontal aligument side-play amount of calculating the alignment offset amount successively, causing by axial picture element, axially align side-play amount, the axial horizontal aligument side-play amount, the axle picture element parameter of hanging down that cause of picture element parameter, the axle picture element that hangs down.Wherein the evaluation index MCC in the curve fitting of carrying out is taken as 0.75.The picture element parameter that calculates is as shown in table 1.

Table 1

Embodiment 2:

Be coated with JSR M206Y type photoresist on silicon chip 7, glue is thick to be 490nm, and with silicon chip last slice to work stage WS.The exposure device lighting condition is set: traditional lighting, NA are 0.57, partial coherence factor is 0.7.The mask R adjustment of the printing plate that will have mirror image FOCAL mark is on mask platform 4.The exposure visual field is 26mm X 8mm, and the exposure field internal labeling evenly distributes according to 3 row, 13 row on the silicon chip, as shown in Figure 7.Control laser instrument switch and work stage movement position adopt the static exposure mode that mirror image FOCAL on the mask is marked under the different defocusing amounts and expose on silicon chip 7.The out of focus scope from-0.9um to 0.9um, stepping 0.12um, totally 16 exposure field.The silicon chip 7 that is exposed utilizes in the exposure device on 6 pairs of silicon chips 7 of optical alignment system mirror image FOCAL mark to aim at and write down aligned position information after later baking is developed, and alignment system reference light grid cycle is 16um.The temperature of back baking is 120 ℃, afterwards the baking time is that 90s, development time are 60s; Utilize the mirror image FOCAL markers align positional information that is obtained, according to the described computation process of step of the present invention, the horizontal aligument side-play amount of calculating the alignment offset amount successively, causing by axial picture element, axially align side-play amount, the axial horizontal aligument side-play amount, the axle picture element parameter of hanging down that cause of picture element parameter, the axle picture element that hangs down.Wherein the evaluation index MCC in the curve fitting of carrying out is taken as 0.75.The picture element parameter that calculates is as shown in table 2.

Table 2

In sum, the inventive method can be to the accurate measurement of vertical axle such as distortion, magnification, translation, rotation picture element parameter when finishing axial picture element parameters in situ detection such as focal plane shift, the curvature of field, astigmatism, obtained the comprehensive parameter of image forming quality of photoetching machine, with the measuring accuracy of the axle picture element parameter of avoiding hanging down in the technology [1] formerly dependence axial picture element degree of correction.Formerly technology [1] and the formerly middle incomplete problem of picture element parameter measurement of technology [2] have been solved.

Claims (10)

1, a kind of detection method of image forming quality of photoetching machine is characterized in that this method comprises the following steps:

The first step: preliminary work:

1. initialization litho machine;

2. going up resist coating at wafer (7) also goes up to worktable (8);

3. preparation has the mask (3) of a plurality of mirror image FOCAL marks, described mirror image FOCAL mark is meant and comprises four quadrants, the figure of each quadrant is made up of the thick lines and the hachure of some cycles, and first quartile is identical with the line orientations of second quadrant, and the rotation symmetry; Third quadrant is identical with the four-quadrant line orientations and mirror image is symmetrical, but with the perpendicular figure of line orientations of first quartile, second quadrant; In this mirror image FOCAL mark, the figure that first quartile and four-quadrant constitute is right FOCAL figure, and the figure that second quadrant and third quadrant lines constitute is left FOCAL figure;

Second step: mark is measured:

1. described mask (3) with mirror image FOCAL mark is gone up to mask platform (4);

2. selected several have the out of focus position of defocusing amount Δ f;

3. adjust illuminator, the lighting condition and the process conditions of exposure device are set;

4. the motion of Control work platform (8) and mask platform (4) makes the wafer (7) that scribbles photoresist in selected a series of out of focus position exposure;

5. the wafer that is exposed (7) carries out the back baking or develop in baking back, back;

6. utilize the reference grating of optical alignment system (6) respectively two FOCAL figures about the mirror image FOCAL mark on the wafer (7) to be aimed at, write down its aligned position coordinate, and be designated as P _L(x _L, y _L) and P _R(x _R, y _R);

The 3rd step: data processing:

The calculating of 1. horizontal aligument side-play amount: according to the theoretical position coordinate P of two FOCAL figure mark imagings in the exposure visual field about mirror image FOCAL mark _OL(x _OL, y _OL) and P _OR(x _OR, y _OR), and utilize their aligned position information to calculate the mirror image FOCAL mark left and right sides two-part horizontal aligument side-play amount AO respectively by (A) formula _LWith AO _R, in Cartesian coordinates: the horizontal aligument side-play amount of directions X is designated as Δ x _LWith Δ x _RThe horizontal aligument side-play amount of Y direction is designated as Δ y _LWith Δ y _R:

$\left\{\begin{array}{c}\mathrm{\&Delta;}{x}_L=x_L-x_{0L}\\ \mathrm{\&Delta;}{y}_L=y_L-y_{0L}\\ {\mathrm{\&Delta;x}}_R=x_R-x_{0R}\\ \mathrm{\&Delta;}{y}_R=y_R-y_{0R}\end{array}\right.---\left(A\right)$

2. the axially calculating of the horizontal aligument side-play amount that causes of picture element: the horizontal aligument side-play amount AO that causes to picture element by horizontal aligument side-play amount reference axis ^v, i.e. Δ x ^vOr Δ y ^v, calculate with following formula:

${\mathrm{AO}}^v=2{\mathrm{AO}}_R^v=-2{\mathrm{AO}}_L^v={\mathrm{AO}}_R-{\mathrm{AO}}_L;---\left(B\right)$

3. axially align the calculating of side-play amount: the horizontal aligument side-play amount AO that causes according to axial picture element ^vDefocusing amount numerical value Δ f with corresponding utilizes least square method to carry out the biquadratic curve match, obtains (C) formula,

AO ^v＝a ₀+a ₁Δf+a ₂Δf ²+a ₃Δf ³+a ₄Δf ⁴ (C)

A wherein ₀, a ₁, a ₂, a ₃, a ₄Be the every coefficient of polynomial expression, utilize (C) formula to calculate alignment offset amount AO ^v, i.e. Δ x ^vOr Δ y ^vWhen obtaining maximum value, corresponding defocusing amount Δ f=Δ Zx, or numerical value Δ Zx, the Δ Zy of Δ f=Δ Zy are and axially align side-play amount;

4. axial picture element calculation of parameter: by axially aligning offset Zx, Δ Zy match (D) formula, thereby obtain focal plane shift, image planes inclination, the curvature of field and astigmatism:

$\left\{\begin{array}{c}(\mathrm{\&Delta;Zx}+\mathrm{\&Delta;Zy})/2=\mathrm{Zw}+\mathrm{Rx}\&CenterDot;x_0+\mathrm{Ry}\&CenterDot;y_0+\mathrm{FC}\&CenterDot;({x_0}^2+{y_0}^2)\\ \mathrm{average}(\mathrm{\&Delta;Zx}-\mathrm{\&Delta;Zy})=\mathrm{AS}\end{array}\right.---\left(D\right)$

Wherein Δ Zx, Δ Zy, x ₀, y ₀The axially aligning side-play amount and be marked as the theoretical position coordinate of picture of each FOCAL mark in the expression exposure visual field respectively, AS represent astigmatism, and on behalf of the curvature of field, Zw, FC represent optimal focal plane, Rx, Ry to represent respectively around X-axis with around the image planes inclination of Y-axis;

5. horizontal aligument side-play amount match: by horizontal aligument side-play amount AO _L=Δ x _LOr Δ y _LWith AO _R=Δ x _ROr Δ y _RAnd corresponding out of focus numerical value Δ f, utilize least square method to carry out the biquadratic curve match respectively and obtain (E) formula,

$\left\{\begin{array}{c}\mathrm{\&Delta;}{x}_L=b_0+b_1\mathrm{\&Delta;f}+b_2\mathrm{\&Delta;}{f}^2+b_3\mathrm{\&Delta;}{f}^3+b_4\mathrm{\&Delta;}{f}^4\\ \mathrm{\&Delta;}{x}_R=c_0+c_1\mathrm{\&Delta;f}+c_2\mathrm{\&Delta;}{f}^2+c_3\mathrm{\&Delta;}{f}^3+c_4\mathrm{\&Delta;}{f}^4\\ \mathrm{\&Delta;}{y}_L=d_0+d_1\mathrm{\&Delta;f}+d_2\mathrm{\&Delta;}{f}^2+d_3\mathrm{\&Delta;}{f}^3+d_4\mathrm{\&Delta;}{f}^4\\ \mathrm{\&Delta;}{y}_R=e_0+e_1\mathrm{\&Delta;f}+e_2\mathrm{\&Delta;}{f}^2+e_3\mathrm{\&Delta;}{f}^3+e_4\mathrm{\&Delta;}{f}^4\end{array}\right.;---\left(E\right)$

B in the formula ₀, b ₁, b ₂, b ₃, b ₄, c ₀, c ₁, c ₂, c ₃, c ₄, d ₀, d ₁, d ₂, d ₃, d ₄, e ₀, e ₁, e ₂, e ₃, e ₄Be the every coefficient of polynomial expression;

The calculating of the horizontal aligument side-play amount that the axle picture element that 6. hangs down causes: in the E formula, calculate the horizontal aligument side-play amount AO when Δ f=Δ Zx or Δ f=Δ Zy _L=Δ x _LOr Δ y _L, with AO _R=Δ x _ROr Δ y _R, and calculate the horizontal aligument side-play amount AO that causes by the axle picture element that hangs down according to (F) formula ^h, i.e. Δ x ^hWith Δ y ^h:,

$\left\{\begin{array}{c}\mathrm{\&Delta;}{x}^h=\frac{\mathrm{\&Delta;}{x}_R+\mathrm{\&Delta;}{x}_L}{2}{|}_{\mathrm{\&Delta;f}=\mathrm{\&Delta;Zx}}\\ \mathrm{\&Delta;}{y}^h=\frac{\mathrm{\&Delta;}{y}_R+\mathrm{\&Delta;}{y}_L}{2}{|}_{\mathrm{\&Delta;f}=\mathrm{\&Delta;Zy}}\end{array}\right.;---\left(F\right)$

7. the axle picture element calculation of parameter of hanging down: the horizontal aligument side-play amount AO that causes by the axle picture element that hangs down ^hMatch (G) formula, thus image planes translation, image planes rotation, magnification change amount, distortion obtained:

$\left\{\begin{array}{c}\mathrm{\&Delta;}{x}^h=\mathrm{dx}+x_0\mathrm{Mag}-y_0\mathrm{\&phi;}+x_0{r}_0^2{D}_3\\ \mathrm{\&Delta;}{y}^h=\mathrm{dy}+y_0\mathrm{Mag}+x_0\mathrm{\&phi;}+y_0{r}_0^2{D}_3\end{array}\right.---\left(G\right)$

Wherein: dx, dy be marked at X to Y to translation, Mag is the enlargement ratio variable quantity of exposure system, φ for the exposure visual field around the rotation of optical axis, D ₃Third-order distortion for exposure system.

2, the detection method of image forming quality of photoetching machine according to claim 1 is characterized in that described lighting condition and process conditions are meant the coherence factor of illumination and numerical aperture size, photoresist type, photoresist thickness, back baking temperature, back baking time, development time.

3, the detection method of image forming quality of photoetching machine according to claim 1 is characterized in that the quantity that described mirror image FOCAL is marked on the mask should guarantee to have at least 5 marks to be in the exposure visual field with distribution, and is marked at evenly distribution in the visual field.

4, the detection method of image forming quality of photoetching machine according to claim 1, it is characterized in that described a series of out of focus position refers to the position of several defocusing amount Δs f optimal focal plane near, its number should be greater than 5, and to have three out of focus positions at least be to be in the focal depth range of projection objective of imaging optical system of photoetching (5).

5, the detection method of image forming quality of photoetching machine according to claim 1 is characterized in that described wafer (7) refers to have the semiconductor material disk of monocrystalline or polycrystalline structure: silicon wafer, gallium arsenide disk or silicon dioxide disk.

6, the detection method of image forming quality of photoetching machine according to claim 1 is characterized in that described exposure process comprises static stepping exposure and dynamic scan exposure.

7, the detection method of image forming quality of photoetching machine according to claim 1 is characterized in that described optical alignment system (6) for having the optical alignment system with reference to optical grating construction, and its grating cycle and FOCAL mark structure cycle are complementary.

8, the detection method of image forming quality of photoetching machine according to claim 1 is characterized in that the described theoretical position that is marked as picture refers to that the last mirror image FOCAL mark of mask (3) is through becoming the position of desirable picture or paraxial rays imaging behind the projection objective on wafer (7).

9, the detection method of image forming quality of photoetching machine according to claim 1 is characterized in that the numerical value of described defocusing amount Δ f is meant that current exposure plane is the distance of optimal focal plane with respect to reference planes, and its sign representative is with respect to the direction of optimal focal plane.

10, the detection method of image forming quality of photoetching machine according to claim 1, the curve that it is characterized in that described match, its fitting result need be weighed with the multiple correlation factor, the typical threshold of this multiple correlation factor is 0.7, when this factor during less than this threshold value, match again after the reply fitting data screens.

Images