CN117059549A - Electrostatic chuck and manufacturing method thereof - Google Patents
Electrostatic chuck and manufacturing method thereof Download PDFInfo
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- CN117059549A CN117059549A CN202311013966.4A CN202311013966A CN117059549A CN 117059549 A CN117059549 A CN 117059549A CN 202311013966 A CN202311013966 A CN 202311013966A CN 117059549 A CN117059549 A CN 117059549A
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- 238000004519 manufacturing process Methods 0.000 title claims abstract description 15
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 109
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 108
- 239000000919 ceramic Substances 0.000 claims abstract description 60
- 239000012790 adhesive layer Substances 0.000 claims description 32
- 239000000853 adhesive Substances 0.000 claims description 22
- 230000001070 adhesive effect Effects 0.000 claims description 22
- 239000011241 protective layer Substances 0.000 claims description 20
- 239000010410 layer Substances 0.000 claims description 14
- 238000007789 sealing Methods 0.000 claims description 8
- 238000001816 cooling Methods 0.000 claims description 7
- 239000000463 material Substances 0.000 claims description 7
- 239000004593 Epoxy Substances 0.000 claims description 5
- 229920001296 polysiloxane Polymers 0.000 claims description 5
- 229920001774 Perfluoroether Polymers 0.000 claims description 4
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims description 4
- 229920001971 elastomer Polymers 0.000 claims description 4
- UJMWVICAENGCRF-UHFFFAOYSA-N oxygen difluoride Chemical compound FOF UJMWVICAENGCRF-UHFFFAOYSA-N 0.000 claims description 4
- 229920002635 polyurethane Polymers 0.000 claims description 4
- 239000004814 polyurethane Substances 0.000 claims description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 3
- 229920000459 Nitrile rubber Polymers 0.000 claims description 3
- 239000004020 conductor Substances 0.000 claims description 3
- 229920001973 fluoroelastomer Polymers 0.000 claims description 3
- 229910002804 graphite Inorganic materials 0.000 claims description 3
- 239000010439 graphite Substances 0.000 claims description 3
- -1 polytetrafluoroethylene Polymers 0.000 claims description 3
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 3
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 3
- 239000010453 quartz Substances 0.000 claims description 3
- 239000002994 raw material Substances 0.000 claims description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 3
- 229920002379 silicone rubber Polymers 0.000 claims description 3
- 239000004945 silicone rubber Substances 0.000 claims description 3
- 229910001220 stainless steel Inorganic materials 0.000 claims description 3
- 239000010935 stainless steel Substances 0.000 claims description 3
- 230000035882 stress Effects 0.000 abstract description 93
- 238000005530 etching Methods 0.000 abstract description 19
- 230000008646 thermal stress Effects 0.000 abstract description 13
- 230000002829 reductive effect Effects 0.000 abstract description 10
- 230000000694 effects Effects 0.000 abstract description 8
- 230000002411 adverse Effects 0.000 abstract description 3
- 239000000758 substrate Substances 0.000 description 24
- 238000000034 method Methods 0.000 description 16
- 230000007797 corrosion Effects 0.000 description 5
- 238000005260 corrosion Methods 0.000 description 5
- NJPPVKZQTLUDBO-UHFFFAOYSA-N novaluron Chemical compound C1=C(Cl)C(OC(F)(F)C(OC(F)(F)F)F)=CC=C1NC(=O)NC(=O)C1=C(F)C=CC=C1F NJPPVKZQTLUDBO-UHFFFAOYSA-N 0.000 description 5
- 238000001312 dry etching Methods 0.000 description 4
- 239000004065 semiconductor Substances 0.000 description 3
- 239000004925 Acrylic resin Substances 0.000 description 2
- 229920000178 Acrylic resin Polymers 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000003822 epoxy resin Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 230000036961 partial effect Effects 0.000 description 2
- 229920000647 polyepoxide Polymers 0.000 description 2
- 229920005749 polyurethane resin Polymers 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 239000012809 cooling fluid Substances 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000011229 interlayer Substances 0.000 description 1
- 230000009545 invasion Effects 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 238000005459 micromachining Methods 0.000 description 1
- 229920002120 photoresistant polymer Polymers 0.000 description 1
- 238000001020 plasma etching Methods 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
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- 229920002050 silicone resin Polymers 0.000 description 1
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping
- H01L21/6831—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using electrostatic chucks
- H01L21/6833—Details of electrostatic chucks
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Manufacturing & Machinery (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Container, Conveyance, Adherence, Positioning, Of Wafer (AREA)
Abstract
The application provides an electrostatic chuck and a manufacturing method thereof, wherein a containing part is arranged on an aluminum base and a stress piece is embedded in the containing part, and as the linear thermal expansion coefficient of the stress piece is smaller than that of the aluminum base and the compressive strength of the stress piece is larger than that of the aluminum base, part of the thermal stress of the aluminum base is applied to the stress piece at high temperature, the stress piece blocks the thermal stress of the aluminum base from being transmitted inwards, the aluminum base part in the stress piece, particularly the bonding surface of the aluminum base and a ceramic disc, receives smaller stress, and the deformation is greatly reduced; when the electrostatic chuck is subjected to the working condition that the temperature is frequently changed, the aluminum base with the stress piece can eliminate the adverse effect on the flatness of the ceramic disc caused by differential deformation as much as possible, so that the etching effect is improved.
Description
Technical Field
The application relates to the technical field of semiconductor manufacturing, in particular to an electrostatic chuck and a manufacturing method thereof.
Background
The etching technology is an important process in the processing of semiconductor components and integrated circuits, and is applied to the processing of fine patterns such as thin film circuits, printed circuits and the like. In the dry etching of semiconductor devices, the etching rate is highly dependent on temperature and its uniformity, and therefore it is extremely important to control the substrate temperature of each etching step as accurately as possible. For example, etching of complex stacked substrates requires stepwise changes in substrate temperature to optimize profile, critical dimensions, and etch selectivity. However, in a typical plasma etching operation, reactive ions, atoms and radicals in the plasma may physically/chemically react with the material of the substrate surface not covered by the photoresist mask, resulting in an increase in the substrate temperature, which may be in an unstable state throughout the etching process. At this time, the temperature of the substrate may be changed from one state to another state by controlling the temperature of the substrate by any method of changing the temperature in a time range that is short with respect to the etching process time of the single substrate.
Electrostatic chucks (Electrostatic Chuck, ESC) are widely used in place of mechanical chucks for chucking workpieces to be processed. Meanwhile, the electrostatic chuck can realize temperature accurate control by alternately performing cooling and heating process of the substrate, and improve etching rate to avoid degradation of total yield. The main body of the conventional electrostatic chuck for dry etching is a ceramic disk and an aluminum base, which are connected by an interlayer adhesive. A heating electrode is embedded in the ceramic disk and connected to a temperature sensor that can be coupled to a temperature control system to maintain the ceramic disk temperature at a selectable set point. The aluminum base contains cooling water channels inside, which are maintained at a relatively constant temperature by the heat exchange system of the cooling fluid circuit.
An electrostatic chuck having a substrate to be processed adsorbed thereon, the top surface of which is in direct contact with the substrate to be processed, thus requiring excellent flatness of the top surface of the electrostatic chuck, which would otherwise hinder micro-machining of the substrate. The electrostatic chuck is used as a heat source to provide accurate and uniform temperature control for the substrate to be etched, the linear thermal expansion coefficient of the aluminum base is far greater than that of the ceramic disc, when the temperature is changed, larger deformation difference is generated between the ceramic disc and the aluminum base, and the ceramic disc is driven to deform along with the aluminum base, so that the planeness of the top surface of the ceramic disc is finally deteriorated. In the actual use process, the frequent high-low temperature cycle change working condition set by the etching equipment increases the frequency of differential deformation of the aluminum base and the ceramic disc, so that the stable flatness of the electrostatic chuck is difficult to ensure in one procedure, and further the flatness of the substrate adsorbed on the electrostatic chuck is deteriorated. In the etching process, the small difference of the surface flatness of the substrate may cause large etching deviation, thereby affecting the etching effect of the substrate. In addition, if the thermal deformation of the aluminum base cannot be relieved in time, the adhesive between the aluminum base and the ceramic disc is easily stretched repeatedly, which is a great challenge for the tensile strength of the adhesive. Once the partial bond paste is broken, the reliability of the aluminum base and ceramic disk connection is reduced, which can severely compromise the durability of the electrostatic chuck.
Japanese patent No. 2011091297a discloses a second adhesive layer provided between a first adhesive layer of a heater and an aluminum base, the second adhesive layer having a lower viscosity than the first adhesive layer and being in a soft gel form after curing. Therefore, the second adhesive layer can be used as a stress relieving layer, and can relieve stress generated on the aluminum base by frequent temperature change during the use of the electrostatic chuck. However, the addition of an additional layer of adhesive increases the overall bond line thickness, which tends to reduce the thermal conductivity of the bond line. When the ceramic disk receives a large amount of heat transferred from the substrate, the heat is less likely to be conducted to the cooling system of the susceptor through the thick adhesive layer, so that the temperature of the substrate may be too high or uneven, and the etching effect is affected. In addition, the method can not fundamentally solve the problem of deformation of the bonding surface caused by overlarge thermal stress of the aluminum base.
Disclosure of Invention
In view of the above, the present application provides an electrostatic chuck and a method for manufacturing the same, which can effectively solve the problem of deformation of an adhesive surface caused by excessive thermal stress of an aluminum base.
The application provides an electrostatic chuck, which comprises an aluminum base and a ceramic disk, wherein the aluminum base is provided with a first surface, the ceramic disk is provided with a second surface, and the first surface is connected with the second surface through an adhesive layer; the first surface is provided with a containing part formed by sinking the aluminum base from the first surface, and a stress piece is arranged in the containing part; the linear thermal expansion coefficient of the stress piece is smaller than that of the aluminum base, and the compressive strength of the stress piece is larger than that of the aluminum base.
In an embodiment, the stress member is tightly fitted with the accommodating portion, and the thickness of the stress member is greater than, equal to, or less than the depth of the accommodating portion.
In an embodiment, the accommodating portion is an annular groove formed in the first surface, and an outer diameter of the accommodating portion is larger than, equal to or smaller than a diameter of the ceramic disc; the stress piece is an annular piece embedded in the accommodating part.
In an embodiment, a plurality of the accommodating parts are arranged at intervals along the radial direction of the aluminum base, and a plurality of the stress pieces are arranged at intervals along the radial direction of the aluminum base and are embedded in the corresponding accommodating parts; and/or, a plurality of accommodating parts are arranged at intervals along the circumferential direction of the aluminum base, and a plurality of stress pieces are arranged at intervals along the circumferential direction of the aluminum base and are embedded into the corresponding accommodating parts.
In an embodiment, the accommodating portion is an annular groove or an arc groove formed in the first surface, and the stress member is a corresponding annular member or an arc member.
In one embodiment, the stress member is made of stainless steel, ceramic, graphite or quartz.
In one embodiment, the adhesive layer is provided with one or more layers, and the adhesive layer is formed by curing one or more organic adhesives, wherein the organic adhesives comprise one or more of epoxy resin, silicone resin, polyurethane resin and acrylic resin.
In one embodiment, the raw materials of the bonding layer include a heat conductive material.
In an embodiment, a protective layer is disposed on the periphery of the adhesive layer, and the protective layer is used for sealing the adhesive layer.
In one embodiment, the protective layer is formed by curing one or more organic adhesives, wherein the organic adhesives comprise one or more of epoxy resin, organic silicon resin, polyurethane resin and acrylic resin; or the protective layer is a sealing ring, and the material of the protective layer comprises one or more of fluororubber, perfluoroether rubber, nitrile rubber, silicone rubber and polytetrafluoroethylene.
The application also provides a manufacturing method of the electrostatic chuck, which comprises the following steps:
s1: the upper surface of an aluminum base is provided with a containing part;
s2: the aluminum base is treated at high temperature, so that the aluminum base and the accommodating part are heated and thermally expanded;
s3: placing a stress piece into the accommodating part, enabling the stress piece to form tight fit with the inner wall of the accommodating part, and cooling to room temperature;
s4: and connecting a ceramic disc on the upper surface of the aluminum base by using an adhesive to prepare the electrostatic chuck.
In an embodiment, the accommodating portion is annular.
In one embodiment, the high temperature treatment in step S2 is performed at a temperature 0 ℃ to 20 ℃ higher than the conventional use temperature of the electrostatic chuck.
In summary, the present application provides an electrostatic chuck and a method for manufacturing the same, in which a receiving portion is formed on an aluminum base and a stress member is embedded in the receiving portion, and since a linear thermal expansion coefficient of the stress member is smaller than that of the aluminum base, and a compressive strength of the stress member is greater than that of the aluminum base, a portion of a thermal stress of the aluminum base is applied to the stress member at a high temperature, and the stress member blocks the thermal stress of the aluminum base from being transmitted inwards, and an adhesive surface of the aluminum base and a ceramic disc in the stress member, particularly, receives smaller stress, and a deformation amount is also greatly reduced; when the electrostatic chuck is subjected to the working condition that the temperature is frequently changed, the aluminum base with the stress piece can eliminate the adverse effect on the flatness of the ceramic disc caused by differential deformation as much as possible, so that the etching effect is improved.
Drawings
Fig. 1 is a schematic diagram of an assembled structure of an aluminum base and a stress member of an exemplary electrostatic chuck according to the present application.
FIG. 2 is an exploded view of the aluminum base and stress member of FIG. 1.
Fig. 3 is a cross-sectional view of an electrostatic chuck in accordance with an embodiment of the present application.
Fig. 4 is a cross-sectional view of an electrostatic chuck in accordance with another embodiment of the present application.
Fig. 5 is a cross-sectional view of an electrostatic chuck in accordance with another embodiment of the present application.
Fig. 6 is a schematic process flow diagram of a method of manufacturing an electrostatic chuck according to the present application.
Fig. 7 is a partial structural cross-sectional view of the electrostatic chuck manufactured by the manufacturing method of fig. 6.
In the figure, a 10-aluminum base; 12-ceramic discs; 14-a first surface; 16-a second surface; 18-an adhesive layer; 20-an accommodating part; 22-stress member; 24-a protective layer; 30-a first seat; 32-a second seat; 34-substrate.
Detailed Description
Before the embodiments are explained in detail, it is to be understood that the application is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The application is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of the terms "comprising," "including," "having," and the like are intended to encompass the items listed thereafter and equivalents thereof as well as additional items. In particular, when "a certain element" is described, the present application is not limited to the number of the element as one, but may include a plurality of the elements.
Referring to fig. 1 to 3, the present application provides an electrostatic chuck, which includes an aluminum base 10 and a ceramic disc 12, wherein the aluminum base 10 has a first surface 14, the ceramic disc 12 has a second surface 16, the first surface 14 and the second surface 16 are connected by an adhesive layer 18, the first surface 14 is provided with a receiving portion 20 formed by invaginating from the first surface 14 to the aluminum base 10, and a stress member 22 is disposed in the receiving portion 20, and the stress member 22 is used for sharing stress applied to the aluminum base 10, so as to effectively reduce the problem of deformation of an adhesive surface caused by overlarge thermal stress of the aluminum base 10.
The aluminum base 10 is integrally cylindrical and includes a first base 30 and a second base 32 connected to a central area of the first base 30, the diameter of the second base 32 is smaller than that of the first base 30, the first base 30 and the second base 32 are, for example, integrally formed structures, and the first surface 14 is a surface of the second base 32 facing away from the first base 30, and is shown as a top surface of the second base 32. The ceramic disk 12 is also cylindrical, and the second surface 16 is a surface of the ceramic disk 12 opposite to the aluminum base 10, and is shown as a bottom surface of the ceramic disk 12.
In the illustrated embodiment, the stress member 22 is a tight fit with the receiving portion 20, and the thickness of the stress member 22 is greater than, equal to, or less than the depth of the receiving portion 20.
In the illustrated embodiment, the receiving portion 20 is a circular annular groove disposed about the periphery of the first surface 14. In other embodiments, the accommodating portion 20 may have other designs, for example, the accommodating portion 20 may include a plurality of groove structures disposed at the periphery of the first surface 14 and arranged at intervals along the circumferential direction, and correspondingly, the stress member 22 may include a plurality of split stress elements corresponding to the groove structures one to one. Alternatively, a plurality of accommodating portions 20 are provided, the plurality of accommodating portions 20 are arranged at intervals along the radial direction of the aluminum base 10, and a plurality of stress pieces 22 are arranged at intervals along the radial direction of the aluminum base 10 and are embedded in the corresponding accommodating portions 20; and/or, the plurality of accommodating parts 20 are arranged at intervals along the circumferential direction of the aluminum base 10, and the plurality of stress pieces 22 are arranged at intervals along the circumferential direction of the aluminum base 10 and are embedded in the corresponding accommodating parts 20.
In some embodiments, the stress members 22 may be provided in plurality, the plurality of stress members 22 may be arranged at intervals along the radial direction square of the aluminum base 10, and/or the plurality of stress members 22 may be arranged at intervals along the circumferential direction of the aluminum base 10.
In this embodiment, the stress member 22 has a circular ring shape matching the shape of the accommodating portion 20. In other embodiments, the accommodating portion 20 and the stress element 22 may have other shapes, so long as they can share the stress of the aluminum base 10. For example, the accommodating portion 20 is an annular groove or an arc groove provided on the first surface 14, and the stress member 22 is a corresponding annular member or an arc member. In the application, the accommodating part 20 and the stress piece 22 are both arranged in a circular ring shape, so that the stress can be evenly shared, and the deformation of the bonding surface of the aluminum base is further reduced.
Preferably, the stress element 22 is a tight fit with the receiving portion 20 to better accommodate compressive stresses from outside the aluminum base 10.
In the present application, the coefficient of linear thermal expansion of the stress member 22 may be set smaller than that of the aluminum base 10, and the compressive strength of the stress member 22 is greater than that of the aluminum base 10, so that the stress member 22 can bear more thermal stress. Specifically, the stress member 22 may be made of stainless steel, ceramic, graphite, quartz, or the like, and preferably made of ceramic.
The adhesive layer 18 may be provided with one or more layers and cured with one or more organic adhesives, which may include one or more of epoxy, silicone, polyurethane, acrylic, etc., preferably silicone with elasticity to absorb some of the thermal stresses. The adhesive layer 18 may also be provided in a multi-layer structure, which may be made of different materials, and has an overall thickness not higher than that of the adhesive layer in the conventional electrostatic chuck, so as to avoid the increase in the overall thickness of the adhesive layer and the decrease in thermal conductivity. Preferably, the raw material of the adhesive layer 18 further includes a heat conductive material to enhance the heat conductive property of the adhesive layer 18.
The dry etching process relies on an etching gas containing F, cl and the like, which is ionized into plasma of ions, atoms, free radicals and the like under the action of an RF power supply. The plasma can penetrate from the gap between the ceramic disk 12 and the sides of the aluminum pedestal 10, corroding and removing the adhesive layer 18, which can cause problems with the electrostatic chuck causing adhesive failure within the substrate support assembly, and the loss of adhesive material can accelerate the separation rate of the ceramic disk 12 from the aluminum pedestal 10. Therefore, the etching electrostatic chuck must be focused on the problem of edge corrosion protection.
In the application, the protective layer 24 is arranged on the periphery of the bonding layer 18, and the protective layer 24 is used for sealing the bonding layer 18, so that the bonding layer 18 is isolated from the outside, and corrosion damage caused by invasion of plasma of corrosive gas into the bonding layer 18 is avoided. The protective layer 24 may be cured from one or more organic adhesives including one or more of epoxy, silicone, polyurethane, acrylic, etc., preferably epoxy with good corrosion resistance.
In other embodiments, the protection layer 24 may also be a sealing ring, where the sealing ring is made of one or more of fluororubber, perfluoroether rubber, nitrile rubber, silicone rubber, polytetrafluoroethylene, etc., and the sealing ring is of a type including O-type, rectangular, T-type, triangular, etc. with different cross-sectional shapes, preferably perfluoroether rubber with good corrosion resistance.
The outer diameter of the receiving portion 20 may be set to be larger than the diameter of the ceramic disc 12, or the outer diameter of the receiving portion 20 is equal to the diameter of the ceramic disc 12, or the outer diameter of the receiving portion 20 is smaller than the diameter of the ceramic disc 12. In the embodiment shown in fig. 3 to 5, the outer diameter of the receiving portion 20 is set smaller than the diameter of the ceramic disc 12.
In the embodiment shown in fig. 3, the thickness of the stress member 22 is greater than the depth of the accommodating portion 20, i.e. the upper surface of the stress member 22 is higher than the first surface 14, and the portion of the stress member 22 protruding from the accommodating portion 20 is embedded in the adhesive layer 18, so that the stress member 22 is fixedly connected to the ceramic disc 12 through the adhesive layer 18. In this embodiment, the stress member 22 is higher than the bonding surface of the aluminum base 10, so that the area of the bonding layer 18 exposed to the corrosive gas can be greatly reduced, and the corrosion of the bonding layer 18 can be further slowed down. The outer surface of the protective layer 24 is flush with the outer surface of the ceramic disc 12, and the inner surface of the protective layer 24 is flush with the radially outer side wall of the receiving portion 20. The side of the ceramic disk 12 facing away from the aluminum base 10 is electrostatically attracted to a substrate 34, the diameter of the ceramic disk 12 being smaller than the diameter of the second pedestal 32.
In the embodiment shown in fig. 4, the thickness of the stress element 22 is equal to the depth of the receiving portion 20, i.e. the upper surface of the stress element 22 is flush with the first surface 14, the outer surface of the protective layer 24 is flush with the outer surface of the ceramic disc 12, the inner surface of the protective layer 24 is flush with the radially outer side wall of the receiving portion 20, and the stress element 22 is fixedly connected to the ceramic disc 12 by the adhesive layer 18. The side of the ceramic disk 12 facing away from the aluminum base 10 is electrostatically attracted to a substrate 34, the diameter of the ceramic disk 12 being smaller than the diameter of the second pedestal 32.
In the embodiment shown in fig. 5, the thickness of the stress element 22 is smaller than the depth of the accommodating portion 20, that is, the upper surface of the stress element 22 is lower than the first surface 14, so that a hollow portion is formed between the upper surface of the stress element 22 and the first surface 14, and the portion of the adhesive layer 18 corresponding to the accommodating portion 20 extends into the hollow portion, so that the adhesive of the adhesive layer 18 fills the hollow portion, and the stress element 22 is connected and fixed with the ceramic disc 12 through the adhesive layer 18. The outer surface of the protective layer 24 is flush with the outer surface of the ceramic disc 12, and the inner surface of the protective layer 24 is flush with the radially outer side wall of the receiving portion 20. The side of the ceramic disk 12 facing away from the aluminum base 10 is electrostatically attracted to a substrate 34, the diameter of the ceramic disk 12 being smaller than the diameter of the second pedestal 32.
Referring to fig. 6 and 7, the present application also provides a method for manufacturing the electrostatic chuck, which includes the following steps:
s1: a containing part 20 is arranged on the upper surface of the aluminum base 10;
s2: the aluminum base 10 is treated at a high temperature, so that the aluminum base 10 and the accommodating part 20 are heated and thermally expanded;
s3: placing the stress piece 22 into the accommodating part 20, enabling the stress piece 22 to form tight fit with the inner wall of the accommodating part 20, and cooling to room temperature;
s4: the ceramic disk 12 is attached to the upper surface of the aluminum base 10 by an adhesive to produce an electrostatic chuck.
The accommodating portion 20 may be designed as a ring shape, and the temperature of the high-temperature treatment in the step S2 is higher than the conventional use temperature of the electrostatic chuck by 0 ℃ to 20 ℃. The conventional use temperature is different for different substrate materials and process modes, for example, a dry etching high-temperature electrostatic chuck is adopted, and the etching reaction temperature of certain alpha-Si materials is generally controlled within 30-80 ℃; the temperature control temperature selected by the existing main stream high temperature etching equipment is controlled in the range of 50-300 ℃.
Specifically, an annular receiving portion 20 is formed along the outer periphery of the upper surface of the aluminum base 10, and the outer diameter of the receiving portion 20 may be set to be equal to the outer diameter of the ceramic disk 12, or smaller than, or larger than the outer diameter of the ceramic disk 12. The aluminum base 10 is placed in a high temperature environment for a period of time, so that the aluminum base 10 as a whole and the accommodating part 20 on the upper surface are heated to generate thermal expansion, and uniformly expand outwards along the radial direction. In this embodiment, the high temperature treatment temperature of the aluminum base 10 is 0 ℃ to 20 ℃ higher than the conventional use temperature of the electrostatic chuck, and specifically, the treatment time can be set to be 50 ℃ to 320 ℃ and more than 2 hours. At this time, the normal temperature stress piece 22 is placed in the accommodating portion 20 of the high temperature aluminum base 10, so that the stress piece 22 is tightly matched with the inner wall of the accommodating portion 20; after cooling to room temperature, the aluminum base 10 contracts radially inward. Since the outer wall of the stress member 22 is in close contact with the inner wall of the accommodating portion 20 under the condition of high Wen Chushi, the thermal stress at the periphery of the aluminum base 10 is gradually transferred to the stress member 22 during the cooling process, and the outer side of the stress member 22 is subjected to the compressive stress from the outer edge of the aluminum base 10. Because the compressive strength of the stress member 22 made of ceramic material is higher, the stress member 22 can bear larger compressive stress, so that a part of thermal stress born by the aluminum base 10 is applied to the stress member 22, and the continuous inward transmission amount of stress is greatly reduced. The aluminum base 10 portion inside the stress member 22, particularly the bonding surface of the aluminum base 10 and the ceramic disk 12, will receive less stress and the amount of deformation will be greatly reduced. Accordingly, the thermal strain of the bonding surface of the aluminum base 10 and the ceramic disk 12 is reduced, thereby reducing the influence of the differential deformation of the aluminum base 10 and the ceramic disk 12 on the flatness of the ceramic disk 12. Under the same processing condition, the deformation of the inner ring bonding surface of the aluminum base 10 is reduced by 51% -69% compared with the deformation of the upper surface of the outer ring of the aluminum base 10 on average.
The inner ring of the aluminum base 10 refers to a portion of the second base 32 located inside the stress member 22, and the outer ring of the aluminum base 10 refers to a portion of the second base 32 located outside the stress member 22.
In summary, the present application provides an electrostatic chuck and a method for manufacturing the same, in which a receiving portion is formed on an aluminum base and a stress member is embedded in the receiving portion, and since a linear thermal expansion coefficient of the stress member is smaller than that of the aluminum base, and a compressive strength of the stress member is greater than that of the aluminum base, a portion of a thermal stress of the aluminum base is applied to the stress member at a high temperature, and the stress member blocks the thermal stress of the aluminum base from being transmitted inwards, and an adhesive surface of the aluminum base and a ceramic disc in the stress member, particularly, receives smaller stress, and a deformation amount is also greatly reduced; when the electrostatic chuck is subjected to the working condition that the temperature is frequently changed, the aluminum base with the stress piece can eliminate the adverse effect on the flatness of the ceramic disc caused by differential deformation as much as possible, so that the etching effect is improved.
The concepts described herein may be embodied in other forms without departing from the spirit or characteristics thereof. The particular embodiments disclosed are illustrative and not restrictive. The scope of the application is, therefore, indicated by the appended claims rather than by the foregoing description. Any changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.
Claims (13)
1. An electrostatic chuck comprising an aluminum base (10) and a ceramic disk (12), the aluminum base (10) having a first surface (14), the ceramic disk (12) having a second surface (16), the first surface (14) and the second surface (16) being connected by an adhesive layer (18); the first surface (14) is provided with a containing part (20) formed by sinking from the first surface (14) to the aluminum base (10), and a stress piece (22) is arranged in the containing part (20); the linear thermal expansion coefficient of the stress piece (22) is smaller than that of the aluminum base (10), and the compressive strength of the stress piece (22) is larger than that of the aluminum base (10).
2. The electrostatic chuck of claim 1, wherein the stress member (22) is in close fit with the receptacle (20), the stress member (22) having a thickness greater than, equal to, or less than a depth of the receptacle (20).
3. The electrostatic chuck of claim 2, wherein the receiving portion (20) is an annular groove provided in the first surface (14), the receiving portion (20) having an outer diameter greater than, equal to, or less than a diameter of the ceramic disk (12); the stress piece (22) is an annular piece embedded in the accommodating part (20).
4. The electrostatic chuck according to claim 2, wherein a plurality of said receptacles (20) are spaced apart along a radial direction of said aluminum base (10), and a plurality of said stress members (22) are spaced apart along a radial direction of said aluminum base (10) and are embedded in corresponding said receptacles (20); and/or a plurality of the accommodating parts (20) are arranged at intervals along the circumferential direction of the aluminum base (10), and a plurality of the stress pieces (22) are arranged at intervals along the circumferential direction of the aluminum base (10) and are embedded in the corresponding accommodating parts (20).
5. An electrostatic chuck according to claim 4, wherein the receiving portion (20) is an annular groove or an arcuate groove provided in the first surface (14), and the stress member (22) is a corresponding annular or arcuate member.
6. An electrostatic chuck according to claim 1, wherein the stress member (22) is stainless steel, ceramic, graphite or quartz.
7. An electrostatic chuck according to claim 1, wherein the adhesive layer (18) is provided in one or more layers, the adhesive layer (18) being cured from one or more organic adhesives including one or more of epoxy, silicone, polyurethane, acrylic.
8. An electrostatic chuck according to claim 7, characterized in that the raw material of the adhesive layer (18) comprises a heat-conducting material.
9. An electrostatic chuck according to claim 1, characterized in that the periphery of the adhesive layer (18) is provided with a protective layer (24), the protective layer (24) being used for sealing the adhesive layer (18).
10. The electrostatic chuck of claim 9, wherein the protective layer (24) is cured from one or more organic adhesives including one or more of epoxy, silicone, polyurethane, acrylic; or the protective layer (24) is a sealing ring, and the material of the protective layer comprises one or more of fluororubber, perfluoroether rubber, nitrile rubber, silicone rubber and polytetrafluoroethylene.
11. A method of manufacturing an electrostatic chuck, comprising the steps of:
s1: the upper surface of an aluminum base (10) is provided with a containing part (20);
s2: the aluminum base (10) is placed at a high temperature for treatment, so that the aluminum base (10) and the accommodating part (20) are heated and thermally expanded;
s3: placing a stress piece (22) into the accommodating part (20), enabling the stress piece (22) to form tight fit with the inner wall of the accommodating part (20), and cooling to room temperature;
s4: an electrostatic chuck is manufactured by attaching a ceramic plate (12) to the upper surface of the aluminum base (10) using an adhesive.
12. The method of manufacturing an electrostatic chuck according to claim 11, wherein the receiving portion (20) is annular.
13. The method of manufacturing an electrostatic chuck according to claim 11, wherein the high temperature treatment in the step S2 is performed at a temperature 0 ℃ to 20 ℃ higher than a normal use temperature of the electrostatic chuck.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311013966.4A CN117059549A (en) | 2023-08-11 | 2023-08-11 | Electrostatic chuck and manufacturing method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311013966.4A CN117059549A (en) | 2023-08-11 | 2023-08-11 | Electrostatic chuck and manufacturing method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117059549A true CN117059549A (en) | 2023-11-14 |
Family
ID=88652987
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311013966.4A Pending CN117059549A (en) | 2023-08-11 | 2023-08-11 | Electrostatic chuck and manufacturing method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117059549A (en) |
-
2023
- 2023-08-11 CN CN202311013966.4A patent/CN117059549A/en active Pending
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