US20110154843A1

US20110154843A1 - Apparatus for controlling temperature of electrostatic chuck comprising two-stage refrigerant fluid channel

Info

Publication number: US20110154843A1
Application number: US12/959,564
Authority: US
Inventors: Sungyong KO; Minshik KIM; KwangMin Lee; Hwankook CHAE; Dongseok LEE; Keehyun KIM; Weonmook LEE
Original assignee: Individual
Current assignee: DMS Co Ltd
Priority date: 2009-12-31
Filing date: 2010-12-03
Publication date: 2011-06-30
Also published as: CN102129958A; TW201128732A; KR20110078598A; KR101108337B1

Abstract

An apparatus for controlling the temperature of an electrostatic chuck is provided. The apparatus includes an electrostatic chuck including, as a fluid channel part for circulating a refrigerant, a first fluid channel formed in an outer circumference region of the internal and a second fluid channel formed in the whole internal region, and one or more chillers for supplying refrigerant controlled to different temperatures through the first fluid channel or the second fluid channel. The first and second fluid channels are formed in two up/down stages within the electrostatic chuck, thereby being independently capable of the temperatures of a center part and edge part of a wafer.

Description

CROSS REFERENCE

This application claims foreign priority under Paris Convention and 35U.S.C. §119 to Korean Patent Application No. 10-2009-0135449, filed Dec. 31, 2009 with the Korean Intellectual Property Office.

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to the temperature control of an electrostatic chuck. More particularly, the present invention relates to an apparatus for controlling the temperature of an electrostatic chuck including a two-stage refrigerant fluid channel, for independently controlling the temperatures of a center part and edge part of a wafer by forming a first fluid channel of a plane spiral shape for the whole internal of the electrostatic chuck and a second fluid channel of a plane spiral shape for an outer circumference region of the internal of the electrostatic chuck, in two up/down stages.
2. Description of the Related Art
In general, a semiconductor device is obtained by realizing an electronic circuit device through a process of patterning a conductive layer and an insulating layer on a surface of a wafer fixed by an electrostatic force of an electrostatic chuck. In addition to the role of fixing the wafer, the electrostatic chuck is used as a plasma generating electrode. In case that ions and the like generated within a chamber are accelerated and incident on a semiconductor substrate, the temperature of the semiconductor substrate increases because kinetic energy of the ions and the like is converted into thermal energy. Such a thermal change of the wafer induces the dispersion of a Critical Dimension (CD) within the wafer. Thus, in general, the electrostatic chuck is constructed to have a temperature control system. This temperature control system can be one chiller or can be a combination of one chiller and a heater.
Temperature control using the combination of one chiller and the heater provides an advantage of being capable of independently controlling the temperatures of a center part and edge part of a wafer but causes problems that, because the heater should be inserted, the design of the electrostatic chuck and a manufacturing process become complex and, in case of using high bias power as in an oxide etching process, the heater is damaged or a Radio Frequency (RF) noise leads to making control complex and difficult.
Also, in case of using one chiller, there is a problem of not being capable of uniformly and rapidly controlling the whole temperature of a wafer. Particularly, as a CD becomes smaller to 30 nm, a semiconductor manufacturing process becomes complex and in addition, a process condition requires very precise control. Thus, in case of using only one chiller, it cannot perform precise control. As one example, there can be a Spacer Patterning Technology (SPT) or a Double Patterning Technology (DPT). Regarding an Amorphous Carbon Layer (ACL) or polycrystalline silicon film, the former SPT process is performed at a high temperature of more than 40° C. Regarding an oxide film, the former SPT process is performed at a low temperature of less than 40° C. Thus, when respective layers are successively etched, a desired etching characteristic cannot be obtained in case that all processes are performed at the same temperature. Accordingly, in order to perform an in-situ process without getting the wafer out of a chamber, there is a need to rapidly change the temperature of the electrostatic chuck within a short time according to the form and quality of a film during an etching process.
Also, when the temperature of the electrostatic chuck is controlled using only one chiller, the temperatures of the center part and edge part of the wafer cannot be independently controlled. That is, it was required that a CD distribution be controlled 2 nm or less in a process of a CD of 40 nm or less, but it appears that the CD distribution is reduced to 1 nm or less in a process of a CD of 30 nm or less. Accordingly, in order to meet this process condition, there is a need to independently control the temperatures of the center part and edge part of the wafer.

SUMMARY OF THE INVENTION

An aspect of exemplary embodiments of the present invention is to address at least the problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of exemplary embodiments of the present invention is to provide an apparatus for controlling the temperature of an electrostatic chuck including a two-stage refrigerant fluid channel, for independently controlling the temperatures of a center part and edge part of a wafer.
Another aspect of exemplary embodiments of the present invention is to provide an apparatus for controlling the temperature of an electrostatic chuck including a two-stage refrigerant fluid channel, for rapidly changing the temperature of the electrostatic chuck even during a process progress.
According to one aspect of the present invention, apparatus for controlling the temperature of an electrostatic chuck is provided. The apparatus may include an electrostatic chuck and one or more chillers. The electrostatic chuck includes a first fluid channel and a second fluid channel as a fluid channel part for circulating a refrigerant. The first fluid channel is formed in an outer circumference region of the internal of the electrostatic chuck. The second fluid channel is formed in the whole region of the internal of the electrostatic chuck. The chillers supply refrigerant controlled to different temperatures through the first fluid channel or the second fluid channel.
The first fluid channel and the second fluid channel may be formed in two up/down stages within the electrostatic chuck, and may be shaped in a plane spiral structure.
Between the chiller and the fluid channel part, the apparatus may further include an opening/closing valve for controlling the flow of refrigerant between the chiller and the fluid channel part, and a circulating valve for returning refrigerant flowing out from the chiller, and only internally circulating the refrigerant.
The circulating valve may be installed between the chiller and the opening/closing valve.
As described above, the present invention can independently control the temperatures of a center part and edge part of a wafer by forming a first fluid channel of a plane spiral shape for the whole internal of the electrostatic chuck and a second fluid channel of a plane spiral shape for an outer circumference region of the internal of the electrostatic chuck, in two up/down stages.
Also, the present invention can rapidly change the temperature of the electrostatic chuck even during the process progress by supplying refrigerant of different temperatures through a plurality of chillers.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which:

FIG. 1 is a diagram illustrating a construction of a temperature control apparatus according to a first exemplary embodiment of the present invention;

FIG. 2 is a flow diagram illustrating a temperature control method according to FIG. 1;

FIG. 3 is a diagram illustrating a construction of a temperature control apparatus according to a second exemplary embodiment of the present invention;

FIG. 4 is a flow diagram illustrating a temperature control method according to FIG. 3;

FIG. 5 is a diagram illustrating a construction of a temperature control apparatus according to a third exemplary embodiment of the present invention;

FIG. 6 is a flow diagram illustrating a temperature control method according to FIG. 5; and

FIG. 7 is a top-view plane diagram illustrating a shape of a refrigerant fluid channel according to an exemplary embodiment of the present invention.

Throughout the drawings, the same drawing reference numerals will be understood to refer to the same elements, features and structures.

DETAILED DESCRIPTION OF THE INVENTION

Exemplary embodiments of the present invention will now be described in detail with reference to the annexed drawings. In the following description, a detailed description of known functions and configurations incorporated herein has been omitted for conciseness.
FIG. 1 is a diagram illustrating a construction of a temperature control apparatus according to a first exemplary embodiment of the present invention, and is a case including one refrigerant fluid channel and two chillers connecting to the refrigerant fluid channel. FIG. 2 is a flow diagram illustrating a temperature control method according to FIG. 1.
Referring to FIG. 1, the temperature control apparatus 100 according to the first exemplary embodiment of the present invention includes an electrostatic chuck 101, a refrigerant fluid channel 102 formed within the electrostatic chuck 101 and circulating refrigerant flowing out from a plurality of chillers, two chillers 110 and 120 set to different temperatures, and a plurality of valves 110 a, 110 b, 110 c, 120 a, 120 b, and 120 c for controlling the flow of refrigerant between the two chillers 110 and 120 and the refrigerant fluid channel 102. Although not illustrated in FIG. 1, a separate micro computer can be constructed to set the temperatures of the chillers 110 and 120 according to process and control the opening/closing of the plurality of valves 110 a, 110 b, 110 c, 120 a, 120 b, and 120 c.
As illustrated in FIG. 1, the refrigerant fluid channel 102 is formed through the whole internal region of the electrostatic chuck 101. A refrigerant is introduced into an inlet 102 a formed in a bottom part of the electrostatic chuck 101, and flows in the whole internal region of the electrostatic chuck 101 via the refrigerant fluid channel 102, and flows out via an outlet 102 b formed in the bottom part of the electrostatic chuck 101.
The chillers 110 and 120 are devices for controlling the temperature of refrigerant according to a set temperature. The first chiller 110 is set to temperature (T₁), and the second chiller 120 is set to temperature (T₂).
The plurality of valves 110 a, 110 b, 110 c, 120 a, 120 b, and 120 c control the flow of refrigerant between the chillers 110 and 120 and the refrigerant fluid channel 102 of the electrostatic chuck 101. Among the valves 110 a, 110 b, and 110 c connecting to the first chiller 110, the valve (V₁) 110 a is used for again returning refrigerant flowing out from the first chiller 110, to the first chiller 110. Among the valves 110 a, 110 b, and 110 c connecting to the first chiller 110, the valve (V₂) 110 b and the valve (V₃) 110 c are used for controlling the flow of refrigerant between the first chiller 110 and the refrigerant fluid channel 102. Similarly, among the valves 120 a, 120 b, and 120 c connecting to the second chiller 120, the valve (V₄) 120 a is used for again returning refrigerant flowing out from the second chiller 120, to the second chiller 120. Among the valves 120 a, 120 b, and 120 c connecting to the second chiller 120, the valve (V₅) 120 b and the valve (V₆) 120 c are used for controlling the flow of refrigerant between the second chiller 120 and the refrigerant fluid channel 102. This construction can efficiently change the temperature of the electrostatic chuck 101 within a short time according to the form and quality of a film during an etching process even without getting a wafer out of a chamber.
A temperature control method of the above-constructed temperature control apparatus is described in detail with reference to FIG. 2.
Referring to FIGS. 1 and 2, in step 200, the apparatus sets the first chiller 110 to temperature (T₁), and opens the valve (V_I) 110 a and simultaneously closes the valve (V₂) 110 b and the valve (V₃) 110 c. So, a refrigerant is controlled to the temperature (T₁) and circulates in the first chiller 110 in itself.
Similarly, in step 201, the apparatus sets the second chiller 120 to temperature (T₂), and opens the valve (V₄) 120 a and simultaneously closes the valve (V₅) 120 b and the valve (V₆) 120 c. So, a refrigerant is controlled to the temperature (T₂) and circulates in the second chiller 120 in itself.
In step 202, the apparatus judges whether to circulate the refrigerant of the first chiller 110 at the set temperature (T₁) according to process. If circulating the refrigerant of the first chiller 110 at the temperature (T₁), the apparatus proceeds to step 203 and, otherwise, proceeds to step 205 and circulates the refrigerant of the second chiller 120 at the temperature (T₂).
In step 203, the apparatus closes the valve (V₁) 110 a and simultaneously opens the valve (V₂) 110 b and the valve (V₃) 110 c. So, the refrigerant controlled to the temperature (T₁) circulates in the electrostatic chuck 101 through the refrigerant fluid channel 102.
After that, in step 204, the apparatus performs a corresponding process in an environment of the temperature (T₁).
In step 205, the apparatus closes the valve (V₄) 120 a and simultaneously opens the valve (V₅) 120 b and the valve (V₆) 120 c. So, the refrigerant controlled to the temperature (T₂) circulates in the electrostatic chuck 101 through the refrigerant fluid channel 102.
After that, in step 206, the apparatus performs a corresponding process in an environment of the temperature (T₂).
Lastly, if there is a need to perform a process in an environment of a different temperature in step 207, the apparatus proceeds to step 208 and sets temperatures (T₁) and (T₂), repeating steps 200 to 207. If there is no need to perform the process otherwise, the method is terminated.
FIG. 3 illustrates a construction of a temperature control apparatus according to a second exemplary embodiment of the present invention, and is a case including two refrigerant fluid channels and two chillers connecting to the two refrigerant fluid channels. FIG. 4 is a flow diagram illustrating a temperature control method according to FIG. 2. The temperature control apparatus 300 of FIG. 3 has the same construction as the temperature control apparatus 100 of FIG. 1 excepting that refrigerant fluid channels 302 and 303 are formed in two up/down layers within an electrostatic chuck 301.
The refrigerant fluid channels 302 and 303 formed within the electrostatic chuck 301 are described in more detail. The refrigerant fluid channels 302 and 303 are composed of a first refrigerant fluid channel 302 formed at a top part of the electrostatic chuck 301 and a second refrigerant fluid channel 303 formed at a bottom part of the electrostatic chuck 301. The first refrigerant fluid channel 302 is formed in an outer circumference region of the internal of the electrostatic chuck 301. The second refrigerant fluid channel 303 is formed through the whole internal region of the electrostatic chuck 301. This construction can independently control the temperatures of a center part and edge part of a wafer as described in detail in the description of the related art. On the other hand, FIG. 3 illustrates that the first refrigerant fluid channel 302 is positioned above the second refrigerant fluid channel 303, but this is merely an exemplary implementation. According to need, the first refrigerant fluid channel 302 may be positioned below the second referent fluid channel 303.
Referring to FIGS. 3 and 4 below, in step 400, the apparatus sets the first chiller 310 to temperature (T₁), and opens the valve (V₁) 310 a and simultaneously closes the valve (V₂) 310 b and the valve (V₃) 310 c. So, a refrigerant is controlled to the temperature (T₁) and circulates in the first chiller 310 in itself.
Similarly, in step 401, the apparatus sets the second chiller 320 to temperature (T₂), and opens the valve (V₄) 320 a and simultaneously closes the valve (V₅) 320 b and the valve (V₆) 320 c. So, a refrigerant is controlled to the temperature (T₂) and circulates in the second chiller 320 in itself.
In step 402, the apparatus judges whether to circulate the refrigerant of the second chiller 320 at the set temperature (T₂) according to process. If circulating the refrigerant of the second chiller 320 at the temperature (T₂), the apparatus proceeds to step 403 and, otherwise, jumps to step 407, judging whether to perform a next process.
In step 403, the apparatus closes the valve (V₄) 320 a and simultaneously opens the valve (V₅) 320 b and the valve (V₆) 320 c. So, the refrigerant controlled to the temperature (T₂) circulates in the electrostatic chuck 301 through the refrigerant fluid channel 303.
After that, in step 404, the apparatus judges if there is a need to set an edge part of a wafer to a different temperature. The judgment can be implemented through a separate micro computer not illustrated in FIG. 3. As the judgment result, if there is the need to set the edge part to the different temperature, the apparatus proceeds to step 405 and, otherwise, jumps to step 406 and performs a corresponding process.
In step 405, the apparatus closes the valve (V₁) 310 a and simultaneously opens the valve (V₂) 310 b and the valve (V₃) 310 c in order to control the temperature of the edge part. So, the refrigerant controlled to the temperature (T₂) circulates in the electrostatic chuck 301 through the refrigerant fluid channel 302 of the top part.
After that, in step 406, the apparatus performs a corresponding process.
After the corresponding process is performed, in step 407, the apparatus judges whether there is a need to perform a process in a different temperature environment. If there is the need to perform the process in the different temperature environment in step 407, the apparatus proceeds to step 408 and sets temperatures (T₁) and (T₂), repeating steps 400 to 406. If there is no need to perform the different temperature process otherwise, the method is terminated.
FIG. 5 illustrates a construction of a temperature control apparatus according to a third exemplary embodiment of the present invention, and is a case including two refrigerant fluid channels and three chillers connecting to the two refrigerant fluid channels. FIG. 6 is a flow diagram illustrating a temperature control method according to FIG. 5. The temperature control apparatus 500 of FIG. 5 is a combination of the temperature control apparatus 100 of FIG. 1 and the temperature control apparatus 300 of FIG. 3.
Referring to FIGS. 5 and 6, in step 600, the apparatus sets a first chiller 510 to temperature (T₁), and opens a valve (V₁) 510 a and simultaneously closes a valve (V₂) 510 b and a valve (V₅) 510 c. So, a refrigerant is controlled to the temperature (T₁) and circulates in the first chiller 510 in itself.
Similarly, in step 601, the apparatus sets a second chiller 520 to temperature (T₂), and opens a valve (V₄) 520 a and simultaneously closes a valve (V₅) 520 b and a valve (V₆) 520 c. So, a refrigerant is controlled to the temperature (T₂) and circulates in the second chiller 520 in itself.
Similarly, in step 602, the apparatus sets a third chiller 530 to temperature (T₃), and opens a valve (V₇) 530 a and simultaneously closes a valve (V₈) 530 b and a valve (V₉) 530 c. So, a refrigerant is controlled to the temperature (T₃) and circulates in the second chiller 530 in itself.
In step 603, the apparatus judges whether to circulate the refrigerant of the second chiller 520 at the set temperature (T2) according to process. If circulating the refrigerant of the second chiller 520 at the temperature (T₂), the apparatus proceeds to step 604 and, otherwise, jumps to step 606, judging whether to perform a next process.
In step 604, the apparatus closes the valve (V₄) 520 a and simultaneously opens the valve (V₅) 520 b and the valve (V₆) 520 c. So, the refrigerant controlled to the temperature (T₂) circulates in the electrostatic chuck 501 through a refrigerant fluid channel 503.
On the other hand, in step 606, the apparatus closes the valve (V₇) 530 a and simultaneously opens the valve (V₈) 530 b and the valve (V₉) 530 c. So, the refrigerant controlled to the temperature (T₃) circulates in the electrostatic chuck 501 through the refrigerant fluid channel 503.
After that, in step 605, the apparatus judges if there is a need to set an edge part of a wafer to a different temperature. Similarly, the judgment can be implemented through a separate micro computer not illustrated in FIG. 3. As the judgment result, if there is the need to set the edge part to the different temperature, the apparatus proceeds to step 607 and, otherwise, jumps to step 608 and performs a corresponding process.
In step 607, the apparatus closes the valve (V₁) 510 a and simultaneously opens the valve (V₂) 510 b and the valve (V₃) 510 c in order to control the temperature of the edge part. So, the refrigerant controlled to the temperature (T₂) circulates in the electrostatic chuck 501 through the refrigerant fluid channel 502 of the top part.
After that, in step 608, the apparatus performs the corresponding process.
After the corresponding process is performed, in step 609, the apparatus judges whether there is a need to perform a process in a different temperature environment. If there is the need to perform the process in the different temperature environment in step 607, the apparatus proceeds to step 610 and sets temperatures (T₁), (T₂), and (T₃), repeating steps 600 to 608. If there is no need to perform the different temperature process otherwise, the method is terminated.
FIG. 7 is a top-view plane diagram illustrating a shape of a two-stage refrigerant fluid channel according to an exemplary embodiment of the present invention.
As illustrated in FIG. 7, the refrigerant fluid channel is composed of a first refrigerant fluid channel 702 and a second refrigerant fluid channel 703. The first refrigerant fluid channel 702 is formed at an upper layer along an outer circumference region of the internal of an electrostatic chuck 701. The second refrigerant fluid channel 703 is formed at a lower layer throughout the internal of the electrostatic chuck 701. A refrigerant is introduced via a refrigerant inlet 702 a of the first refrigerant fluid channel 702, and flows along the outer circumference region of the internal of the electrostatic chuck 701, and flows out via a refrigerant outlet 702 b. On the other hand, a refrigerant is introduced via a refrigerant inlet 703 a of the second refrigerant fluid channel 703, and flows along the whole region of the internal of the electrostatic chuck 701, and flows out via a refrigerant outlet 703 b. The refrigerant fluid channel 701 is, as illustrated in FIG. 7, constructed to have a plane spiral-shape structure, but this is merely an exemplary implementation, and the refrigerant fluid channel 701 may be constructed in various forms according to the need of those skilled in the art. Also, the present invention illustrates that the first and second refrigerant fluid channels run on the upper layer and the lower layer within the electrostatic chuck 701 but, according to an exemplary implementation, the first and second refrigerant fluid channels 702 and 703 may be formed at one layer. Also, the first refrigerant fluid channel 702 may be constructed to have a greater radius than the second refrigerant fluid channel 703, and the second refrigerant fluid channel 703 may be constructed to have a greater radius than the first refrigerant fluid channel 702.
While the invention has been shown and described with reference to a certain preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. An apparatus for controlling the temperature of an electrostatic chuck, the apparatus comprising:

an electrostatic chuck comprising a first fluid channel and a second fluid channel as a fluid channel part for circulating a refrigerant, the first fluid channel being formed in an outer circumference region of the internal of the electrostatic chuck, and the second fluid channel being formed in the whole region of the internal of the electrostatic chuck; and

one or more chillers for supplying refrigerant controlled to different temperatures through the first fluid channel or the second fluid channel.

2. The apparatus of claim 1, wherein the first fluid channel and the second fluid channel are formed in two up/down stages within the electrostatic chuck.

3. The apparatus of claim 1, wherein the first fluid channel and the second fluid channel are shaped in a plane spiral structure.

4. The apparatus of claim 1, further comprising: between the chiller and the fluid channel part,

an opening/closing valve for controlling the flow of refrigerant between the chiller and the fluid channel part; and

a circulating valve for returning refrigerant flowing out from the chiller, and only internally circulating the refrigerant.

5. The apparatus of claim 4, wherein the circulating valve is installed between the chiller and the opening/closing valve.