CN112838040B - Wafer clamping device and plasma processing equipment - Google Patents
Wafer clamping device and plasma processing equipment Download PDFInfo
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- CN112838040B CN112838040B CN201911168656.3A CN201911168656A CN112838040B CN 112838040 B CN112838040 B CN 112838040B CN 201911168656 A CN201911168656 A CN 201911168656A CN 112838040 B CN112838040 B CN 112838040B
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- 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
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- 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
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
- B23Q3/00—Devices holding, supporting, or positioning work or tools, of a kind normally removable from the machine
- B23Q3/15—Devices for holding work using magnetic or electric force acting directly on the work
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
- C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
- C23C16/458—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating characterised by the method used for supporting substrates in the reaction chamber
- C23C16/4582—Rigid and flat substrates, e.g. plates or discs
- C23C16/4583—Rigid and flat substrates, e.g. plates or discs the substrate being supported substantially horizontally
- C23C16/4585—Devices at or outside the perimeter of the substrate support, e.g. clamping rings, shrouds
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
- C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
- C23C16/458—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating characterised by the method used for supporting substrates in the reaction chamber
- C23C16/4582—Rigid and flat substrates, e.g. plates or discs
- C23C16/4583—Rigid and flat substrates, e.g. plates or discs the substrate being supported substantially horizontally
- C23C16/4586—Elements in the interior of the support, e.g. electrodes, heating or cooling devices
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/32—Gas-filled discharge tubes
- H01J37/32431—Constructional details of the reactor
- H01J37/32715—Workpiece holder
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- 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
- H01L21/687—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 mechanical means, e.g. chucks, clamps or pinches
- H01L21/68714—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 mechanical means, e.g. chucks, clamps or pinches the wafers being placed on a susceptor, stage or support
- H01L21/68757—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 mechanical means, e.g. chucks, clamps or pinches the wafers being placed on a susceptor, stage or support characterised by a coating or a hardness or a material
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- 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
- H01L21/687—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 mechanical means, e.g. chucks, clamps or pinches
- H01L21/68714—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 mechanical means, e.g. chucks, clamps or pinches the wafers being placed on a susceptor, stage or support
- H01L21/68785—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 mechanical means, e.g. chucks, clamps or pinches the wafers being placed on a susceptor, stage or support characterised by the mechanical construction of the susceptor, stage or support
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02N—ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR
- H02N13/00—Clutches or holding devices using electrostatic attraction, e.g. using Johnson-Rahbek effect
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- Power Engineering (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Manufacturing & Machinery (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Mechanical Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Analytical Chemistry (AREA)
- Plasma & Fusion (AREA)
- Container, Conveyance, Adherence, Positioning, Of Wafer (AREA)
- Drying Of Semiconductors (AREA)
- Mechanical Treatment Of Semiconductor (AREA)
Abstract
The embodiment of the application discloses a wafer clamping device, which comprises an electrostatic chuck and a grounding device, wherein an electrostatic electrode plate can be formed inside the electrostatic chuck and can be connected with a direct current power supply, the grounding device can comprise a metal grounding end and a top part which are mutually connected, the metal grounding end is used for being connected with a ground wire, a wafer is fixed on the electrostatic chuck, when plasma is formed above the wafer, the top part is contacted with the plasma to realize the grounding of the wafer, the top part can ground a direct current signal in the electrostatic chuck and block the transmission of a radio frequency signal between the plasma and the ground wire, so that the grounding end can be provided for the direct current signal, namely the grounding end is provided for clamping the wafer, the radio frequency signal can not be grounded through the grounding device, the radio frequency loop and the direct current loop are separated, and the reliability of clamping the wafer is improved.
Description
Technical Field
The present application relates to the field of semiconductor device manufacturing, and more particularly, to a wafer clamping apparatus and a plasma processing apparatus.
Background
In the process of manufacturing a semiconductor device, it is necessary to clamp a substrate to fix the substrate, thereby forming a thin film on the substrate or processing the formed thin film.
For example, the wafer may be held by an electrostatic chuck, and for a monopolar electrostatic chuck, an electrostatic electrode plate may be disposed in the electrostatic chuck, and when a positive dc voltage is applied to the electrostatic electrode plate, an electric field generated by the electrostatic electrode plate may cause polarization of a wafer fixed on the electrostatic chuck, and in order to neutralize charges generated in the wafer, a negative potential may be generated on the surface of the wafer, so that coulomb force generated between potentials of different polarities may cause the wafer to be adsorbed on the electrostatic chuck.
However, the charge on the wafer gradually decreases over time, which is detrimental to the clamping of the wafer by the electrostatic chuck.
Disclosure of Invention
In view of this, embodiments of the present application provide a wafer clamping device and a plasma processing apparatus, which provide a grounding terminal for clamping a wafer, so that a dc loop and a rf loop are separated, and the reliability of wafer clamping is improved.
The embodiment of the application provides a wafer clamping device, which comprises: an electrostatic chuck to which a radio frequency signal is applied, and a grounding device;
an electrostatic electrode plate is formed in the electrostatic chuck and is used for being connected with a direct-current power supply;
the grounding device comprises a grounding part and a top part which are connected with each other, wherein the grounding part is used for connecting with a ground wire; and when a plasma is formed above the wafer, the top part is in contact with the plasma, and the top part is used for enabling a direct current signal generated by the direct current power supply to pass through the plasma to be grounded and blocking transmission of the radio frequency signal between the plasma and the ground wire.
Optionally, the material of the top portion is high resistance silicon or silicon carbide.
Optionally, the grounding part is a metal screw or a metal gasket.
Optionally, the grounding part is made of a nonmetallic material, and the resistance value of the grounding part ranges from 0.1 to 1000MΩ.
Optionally, the grounding device is disposed in a cover ring at the periphery of the electrostatic chuck.
Optionally, the material of the cover ring is at least one of the following materials: quartz, aluminum oxide, aluminum nitride, single crystal silicon, polycrystalline silicon, silicon carbide, silicon nitride, and silicon oxide.
Optionally, the grounding device is multiple.
Optionally, the grounding devices are uniformly distributed in the cover ring.
Optionally, the grounding part is a metal screw, the metal screw comprises a screw rod and a head, the top part covers the head of the metal screw, the screw rod of the metal screw penetrates through the cover ring to be connected with the ground wire, and the top part is exposed to the surface of one side of the cover ring facing the plasma.
Optionally, a focusing ring is further formed between the electrostatic chuck and the cover ring.
Optionally, the top portion is connected to an upper electrode, and the ground portion is connected to a ground line.
The embodiment of the application also provides plasma processing equipment, which comprises the upper polar plate and the wafer clamping device, wherein the wafer clamping device is used for fixing a wafer, and when plasma is formed between the upper polar plate and the wafer, the plasma is used for processing the wafer.
Compared with the prior art, the application has at least the following advantages:
the embodiment of the application provides a wafer clamping device and plasma processing equipment, wherein the wafer clamping device can comprise an electrostatic chuck and a grounding device, an electrostatic electrode plate can be formed inside the electrostatic chuck, the electrostatic electrode plate can be connected with a direct current power supply, the grounding device can comprise a grounding part and a top part which are mutually connected, the grounding part is used for connecting a ground wire, a wafer is fixed on the electrostatic chuck, plasma is formed above the wafer, when the top part is contacted with the plasma, the grounding of the wafer is realized, the top part can enable a direct current signal generated by the direct current power supply in the electrostatic chuck to pass through the plasma to be grounded and block the transmission of a radio frequency signal between the plasma and the ground wire, so that the grounding end can be provided for clamping the wafer by the direct current signal, and the radio frequency signal can not be grounded through the grounding device, so that a radio frequency loop and the direct current loop are separated, and the reliability of wafer clamping is improved.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments described in the present application, and other drawings may be obtained according to the drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic view of a plasma processing chamber according to an embodiment of the present application;
fig. 2 is a schematic diagram of a clamping device according to an embodiment of the present application;
fig. 3 is a schematic diagram of a grounding device according to an embodiment of the present application;
FIG. 4 is a cross-sectional view of the clamping device shown in FIG. 2 taken along the AA direction;
FIG. 5 is a schematic diagram of the current of the electrostatic chuck at different DC voltages;
FIG. 6 is a schematic diagram of the resistance of the electrostatic chuck at different DC voltages;
FIG. 7 is a schematic view of the gas flow rate with the upper electrode grounded;
FIG. 8 is a schematic view of the gas flow rate in the case of grounding with a grounding device;
fig. 9 is a schematic view of the gas flow rate without grounding.
Detailed Description
In order that the above objects, features and advantages of the application will be readily understood, a more particular description of the application will be rendered by reference to the appended drawings.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application, but the present application may be practiced in other ways other than those described herein, and persons skilled in the art will readily appreciate that the present application is not limited to the specific embodiments disclosed below.
In the following detailed description of the embodiments of the present application, reference is made to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration only, and in which is shown by way of illustration only, and in which the scope of the application is not limited for ease of illustration. In addition, the three-dimensional dimensions of length, width and depth should be included in actual fabrication.
Currently, the wafer can be clamped by the electrostatic chuck, for the unipolar electrostatic chuck, an electrostatic electrode plate can be arranged in the electrostatic chuck, when a positive direct current voltage is applied to the electrostatic electrode plate, an electric field generated by the electrostatic electrode plate can lead to the polarization of the wafer fixed on the electrostatic chuck, and in order to neutralize the electric charge generated in the wafer, a negative potential can be generated on the surface of the wafer, so that coulomb force generated between the electric potentials with different polarities can enable the wafer to be adsorbed on the electrostatic chuck.
However, the charge on the wafer may decrease gradually over time, thus decreasing the coulomb force generated between the wafer and the electrostatic chuck, which is detrimental to the clamping of the wafer by the electrostatic chuck. In the prior art, the grounding of the wafer is achieved by the upper electrode or the upper grounding ring, the upper electrode plate may be a shower plate, and referring to fig. 1, a schematic diagram of a plasma processing chamber in an embodiment of the present application is shown, in which after a positive dc power is applied to the electrostatic electrode plate 111 in the electrostatic chuck 110, the wafer 120 is directly grounded through the wafer 120, the plasma 130 on the wafer 120, the upper electrode 140, and the ground wire 150, however, this grounding mode is usually achieved by contacting with metal screws or metal gaskets, part of the rf signals also conduct rf current through these contact points, the rf signals accelerate oxidation of the metal screws or metal gaskets, and the long-term use may cause poor contact between the metal screws or metal gaskets, resulting in the influence on the reliability of grounding of the rf circuit and the wafer 120.
Based on the technical problems, the wafer clamping device and the plasma processing apparatus provided by the embodiments of the application can comprise an electrostatic chuck and a grounding device, an electrostatic electrode plate can be formed inside the electrostatic chuck, the electrostatic electrode plate can be connected with a direct current power supply, the grounding device can comprise an interconnected grounding part and a top part, the grounding part is used for connecting a ground wire, a wafer is fixed on the electrostatic chuck, when a plasma is formed above the wafer, the top part is in contact with the plasma to realize the grounding of the wafer, and the top part can enable a direct current signal in the electrostatic chuck to be grounded and block the transmission of a radio frequency signal between the plasma and the ground wire, so that the grounding end can be provided for clamping the wafer by the direct current signal, and the radio frequency signal can not be grounded through the grounding device to separate a radio frequency loop from the direct current loop, thereby improving the reliability of wafer clamping.
For a better understanding of the technical solutions and technical effects of the present application, specific embodiments will be described in detail below with reference to the accompanying drawings.
Referring to fig. 2, a schematic diagram of a clamping device according to an embodiment of the present application is provided, wherein the clamping device may include an electrostatic chuck 110 and a grounding device 200.
In embodiments of the present application, the electrostatic chuck 110 is used to hold a wafer 120 thereon, and the electrostatic chuck may be a ceramic structure. The electrostatic chuck 110 may be provided with an electrostatic electrode plate 111, and when a positive dc voltage is applied to the electrostatic electrode plate 111, an electric field generated by the electrostatic electrode plate 111 may cause the wafer 120 fixed on the electrostatic chuck 110 to be polarized, and in order to neutralize charges generated in the wafer 120, a negative potential may be generated on the surface of the wafer 120, so that coulomb force generated between potentials of different polarities may cause the wafer 120 to be adsorbed on the electrostatic chuck 110. However, the charge on the wafer 120 may decrease over time, which may reduce the coulomb force generated between the wafer 120 and the electrostatic chuck 110, and may be detrimental to the clamping of the wafer 120 by the electrostatic chuck 110.
A metal base 160 may be disposed under the electrostatic chuck 110, and referring to fig. 4, a cross-sectional view of the clamping structure shown in fig. 2 along the AA direction is shown, with the plasma 130 being added above the electrostatic chuck 110 for ease of understanding. The metal base 160 may be, for example, aluminum or an aluminum alloy, and the metal base 160 may be made to function as a lower electrode by supplying high-frequency power to the metal base 160, for example, at a frequency of 400kHz to 100 MHz. Corresponding to the electrostatic chuck 110, the plasma etching apparatus may further include an upper electrode 140, a gap is formed between the upper electrode and the electrostatic chuck 110, and the upper electrode 140 is made of a conductive material. A plasma 130 may be formed between the upper electrode 140 and the electrostatic chuck 110, and the plasma 130 may be used to process the wafer 120 held on the electrostatic chuck 110, for example, to etch the wafer 120, or to deposit material on the wafer 120, or to clean the wafer 120, etc., under the influence of an electric field between the upper electrode 140 and the electrostatic chuck 110.
The plasma between the upper electrode 140 and the electrostatic chuck 110 may be formed by the process gas being energized by a radio frequency signal, which, in general, may be applied to the electrostatic chuck to energize the process gas between the upper electrode 140 and the electrostatic chuck 110 into a plasma.
In the prior art, the upper electrode 140 may be grounded by being connected to the ground line 150, so that the wafer 120 may be grounded by the wafer 120, the plasma 130, the upper electrode 140, and the ground line 150, however, this grounding mode is usually implemented by contacting with metal screws or metal pads, and the rf signal also conducts rf current through these contact points, and this rf signal accelerates oxidation of the metal screws or metal pads, which may cause poor contact between the metal screws or metal pads after long-term use, resulting in an influence on the reliability of the rf circuit and the grounding of the wafer 120.
In an embodiment of the present application, a grounding device 200 may be provided, where the grounding device 200 may include a grounding portion 201 and a top portion 202 that are interconnected, as shown in fig. 3, the grounding portion 201 is used to connect to a ground wire, when the wafer 120 is fixed on the electrostatic chuck 110, and when the plasma 130 is formed above the wafer 120, as shown in fig. 4, the top portion 202 contacts the plasma 130, and the grounding portion 201 does not contact the plasma 130, since the plasma 130 is used to act on the wafer 120, the plasma 130 contacts the surface of the wafer 120, that is, the wafer 120 may be connected to the top portion 202 through the plasma 130, the top portion 202 is connected to the grounding portion 201, and the grounding portion 201 is connected to the ground wire 150, so that the wafer 120 may implement direct grounding through the wafer 120, the plasma 130, the top portion 202, the grounding portion 201, and the ground wire 150, thereby supplementing charges to the wafer 120 and improving the clamping reliability of the wafer 120. In this way, the dc current is no longer grounded from the wafer 120, the plasma 130 on the wafer 120, the upper electrode 140 to the ground 150.
Meanwhile, the resistance of the top portion 202 is larger, which is equivalent to a short circuit state in the rf circuit, so that the top portion 202 can block the transmission of the rf signal to the ground portion 201, and the impedance in the rf circuit is not changed, so that the plasma is not affected, and the separation of the dc circuit and the rf return is formed.
In an embodiment of the present application, the material of the top portion 202 may be high-resistance silicon or silicon carbide, which is used to prevent rf current from flowing, but only dc current from flowing, and on the other hand, the high-resistance silicon or silicon carbide exposed to the plasma can prevent the impurity from being bombarded by the plasma, so that the processing effect on the wafer is not affected.
Referring to fig. 3 (a), the ground portion 201 may be a metal screw or a metal washer, which may be a copper washer, for example. Of course, referring to fig. 3 (b), the ground portion 201 may be made of a non-metal material, and the resistance value of the ground portion 201 may range from 0.1 to 1000 mega ohms (Mohm, mΩ), and the ground portion 201 and the top portion 202 may have uniform or non-uniform diameters, may be cylindrical, or may have other shapes. In this way, the ground portion 201 can pass a direct current and block a radio frequency current. In this manner, even when the top portion 202 is degraded in performance due to prolonged exposure to plasma, the grounding device 200 is still effective in preventing rf current from flowing therethrough, while only dc current flows therethrough. As an example, the ground portion 201 may be made of a doped organic material.
As a possible implementation, the top portion 202 of the grounding device 200 may be connected to the upper electrode 140, and the ground portion 201 of the grounding device 200 may be connected to the ground line 150, so that electrical connections to the wafer 120, the plasma 130, the top portion 202, the ground portion 201, and the ground line 150 may still be made to achieve grounding of the wafer 120. The top portion 202 can block the rf signal from being grounded through the grounding portion 201, so that the problem that the rf signal accelerates oxidation of metal contact points in the prior art is avoided, the service life of the grounding portion 201 is prolonged, and the reliability of grounding a wafer by using the grounding portion 201 is improved.
As one possible implementation, the grounding device 200 may be disposed in the cover ring 113 around the electrostatic chuck 110, where the material of the cover ring 113 is at least one of the following materials: quartz, aluminum oxide, aluminum nitride, single crystal silicon, polycrystalline silicon, silicon carbide, silicon nitride, and silicon oxide. In this way, the upper electrode 140 may be grounded without a screw or a metal pad, so that the rf circuit is not affected, and even if the surface of the upper electrode 140 is insulated due to the yttrium oxide film formed on the surface of the shower plate as the upper electrode 140, the wafer 120 may be grounded by the grounding device 200 in the cover ring 113 under the condition that the grounding of the wafer 120 is not provided.
In particular, the grounding portion 201 may be a metal screw, the metal screw may include a head and a screw rod, and referring to fig. 3 (a), a top portion 202 may be disposed on the surface of the head of the metal screw, that is, a high-resistance silicon or silicon carbide film is formed on the surface of the head of the metal screw, and it is understood that the high-resistance silicon or silicon carbide film covers the head of the metal screw. After the metal screw is installed in the cover ring 113, the screw shaft of the metal screw may penetrate the cover ring 113 to be connected to the ground line 150, and the head of the metal screw may be higher than the side of the cover ring 113 facing the plasma 130 or flush with the side of the cover ring 113 facing the plasma 130, as shown with reference to fig. 4. Thus, when the wafer 120 is processed by the plasma 130, the plasma 130 is formed above the cover ring 113 while contacting the wafer 120, and the head of the metal screw is not directly contacted with the plasma 130, but contacted with the plasma 130 through the high-resistance silicon or silicon carbide, because the surface of the head of the metal screw is provided with the high-resistance silicon or silicon carbide.
In this way, the wafer 120 may be connected to the high-resistance silicon or silicon carbide film layer through the plasma 130, the high-resistance silicon or silicon carbide film layer is connected to the metal screw, and the metal screw is connected to the ground wire 150, so that the wafer 120 may implement dc grounding through the wafer 120, the plasma 130, the high-resistance silicon or silicon carbide film layer, the metal screw, and the ground wire 150, thereby supplementing charges to the wafer 120 and improving the clamping reliability of the wafer 120.
Specifically, the grounding device 200 may be a plurality of metal screws, for example, a plurality of heads may be provided with a film layer of high-resistance silicon or silicon carbide, and the grounding device 200 may be uniformly disposed in the cover ring 113, as shown in fig. 2, wherein 4 grounding devices 200 are disposed in the cover ring 113, that is, the metal screws include 4 metal screws, and the heads of the 4 metal screws are formed with a film layer of high-resistance silicon or silicon carbide.
A focus ring 112 may also be formed between the electrostatic chuck 110 and the cover ring 113, the focus ring 112 may have an inner portion adjacent the electrostatic chuck 110 and may be flush with the electrostatic chuck 110 such that the inner portion of the focus ring 112 may be positioned above the inner portion of the focus ring 112, i.e., the inner portion of the focus ring 112 may be positioned below the edge of the wafer 120, when the wafer 120 extends out of the electrostatic chuck 110. The outer portion of the focus ring 112, through which the wafer 120 may be positioned onto the electrostatic chuck 110, may be thicker than the inner portion, with the outer portion of the focus ring 112 being higher in upper surface than the inner portion.
The material of the focus ring 112 may be at least one of the following materials: quartz, aluminum oxide, aluminum nitride, single crystal silicon, polycrystalline silicon, silicon carbide, silicon nitride, silicon oxide, and the like. Below the focus ring 112 may be provided an underlying structure for electrically extending the plasma 130 facing region of the electrostatic chuck 110.
Referring to fig. 5, there are schematic diagrams of currents of electrostatic chucks under different dc voltages, including an electrostatic chuck current obtained by applying a certain dc voltage in a case of grounding (SH-GND) through an upper electrode, a case of grounding (Si pin-GND) through a grounding device 200, and a case of ungrounded (fuse floating), wherein the grounding device 200 includes a metal screw having a head surface formed with a film layer of high-resistance silicon or silicon carbide, and an upper limit (horizontal dotted line) of the electrostatic chuck current is 200uA in V and an upper limit (vertical dotted line) of the electrostatic chuck current is 700V, and electrostatic chuck currents corresponding to a case of grounding through the grounding device 200 and ungrounded are 65uA, 51uA, respectively, whereby it is known that substantially the same electrostatic chuck current can be generated by grounding through the upper electrode and grounding through the grounding device 200.
Referring to fig. 6, there are schematic electrical resistances of electrostatic chucks under different dc voltages, including an electrostatic chuck resistance obtained by applying a certain dc voltage in the case of grounding via the upper electrode, in the case of grounding via the grounding device 200, and in the case of non-grounding, wherein the grounding device 200 includes a metal screw having a head surface formed with a film layer of high-resistance silicon or silicon carbide, the abscissa is dc voltage, the ordinate is V, the ordinate is resistance of the electrostatic chuck, and the ordinate is mΩ, and when the voltage at the vertical dotted line position is 700V, the upper electrode is grounded, and the resistances corresponding to the grounding via the grounding device 200 and the non-grounding are 10mΩ, 14mΩ, and 44mΩ, respectively. It can be seen that the upper electrode is grounded and the grounding device 200 is grounded, so that substantially the same resistance can be generated.
In the embodiment of the application, the clamping capability of the electrostatic chuck on the wafer can be verified, in general, a gas channel can be arranged in the base and the electrostatic chuck and used for introducing cooling gas to the back surface of the wafer, so that the temperature is reduced, helium (He) is cooled, when the pressure of the cooling gas is high, the cooling gas has upward impact force on the wafer, if the clamping capability of the electrostatic chuck on the wafer is insufficient, the wafer can be flushed by the cooling gas, at the moment, the wafer is separated from the electrostatic chuck, the flow rate of the cooling gas suddenly increases, and the fixing of the electrostatic chuck on the wafer fails.
Accordingly, the clamping capability of the electrostatic chuck can be verified by using different pressures of the cooling gas, and referring to fig. 7, 8 and 9, the gas flow is respectively illustrated in the case of grounding through the upper electrode, the case of grounding through the grounding device 200, and the case of ungrounded, wherein the grounding device 200 includes a metal screw with a head surface formed with a high-resistance silicon or silicon carbide film, the horizontal axis is a direct current voltage, the vertical axis is a flow of He, the vertical axis is sccm, different lines can represent different He pressures, and the units are torr, such as 5torr, 10torr, 15torr, 20torr, 25torr, 30torr, 35torr, and the like. Therefore, it can be seen that the wafer is always fixed on the electrostatic chuck by the dc voltage of 200V required for grounding the upper electrode, the wafer is always fixed on the electrostatic chuck by the dc voltage of 200V required for grounding the grounding device 200, and the wafer is always fixed on the electrostatic chuck by the dc voltage of 500V required for grounding the wafer, which means that the wafer is grounded by the grounding device 200 and the wafer is held reliably under lower dc voltage by grounding the upper electrode, that is, the electrostatic chuck adsorption effect similar to that of the upper electrode is achieved by grounding by the grounding device 200.
The embodiment of the application provides a wafer clamping device, which comprises an electrostatic chuck and a grounding device, wherein an electrostatic electrode plate can be formed inside the electrostatic chuck and can be connected with a direct current power supply, the grounding device can comprise a grounding part and a top part which are mutually connected, the grounding part is used for being connected with a ground wire, a wafer is fixed on the electrostatic chuck, plasma is formed above the wafer, the top part is contacted with the plasma, the grounding of the wafer is realized, the top part can enable a direct current signal in the electrostatic chuck to be grounded and block the transmission of a radio frequency signal between the plasma and the ground wire, so that a grounding end can be provided for the direct current signal, namely, the grounding end is provided for clamping the wafer, the radio frequency signal can not be grounded through the grounding device, a radio frequency loop and a direct current loop are separated, and the reliability of clamping the wafer is improved.
The embodiment of the application also provides plasma processing equipment, which comprises the upper polar plate and the wafer clamping device, wherein the wafer clamping device is used for fixing a wafer, and when plasma is formed between the upper polar plate and the wafer, the plasma is used for processing the wafer. It is understood that the upper plate may not be dc grounded when the wafer clamping device is grounded by the grounding device. The wafer clamping device may refer to the description of the above embodiments, and will not be described herein.
The above description is only of the preferred embodiment of the present application, and is not intended to limit the present application in any way. While the application has been described with reference to preferred embodiments, it is not intended to be limiting. Any person skilled in the art can make many possible variations and modifications to the technical solution of the present application or modifications to equivalent embodiments using the methods and technical contents disclosed above, without departing from the scope of the technical solution of the present application. Therefore, any simple modification, equivalent variation and modification of the above embodiments according to the technical substance of the present application still fall within the scope of the technical solution of the present application.
Claims (12)
1. A wafer clamping apparatus, comprising: an electrostatic chuck and a grounding device;
an electrostatic electrode plate is formed inside the electrostatic chuck and is used for being connected with a direct-current power supply, and radio frequency signals can be applied to the electrostatic chuck;
the grounding device comprises a grounding part and a top part which are connected with each other, wherein the top part is positioned at the upper part of the grounding part, and the grounding part is used for being connected with a ground wire; the electrostatic chuck is used for placing a wafer, when plasma is formed above the wafer, the top portion is in contact with the plasma, the grounding portion is not in contact with the plasma, the grounding device is used for enabling a direct current signal generated by the direct current power supply to pass through the plasma for grounding, and the resistor of the top portion is arranged to enable the top portion to be equivalent to a short circuit state in a radio frequency loop, so that the grounding device can block transmission of the radio frequency signal between the plasma and the ground wire.
2. The device of claim 1, wherein the material of the top portion is high resistance silicon or silicon carbide.
3. The device of claim 2, wherein the grounding portion is a metal screw or a metal washer.
4. The device of claim 2, wherein the ground portion is made of a non-metallic material, and the ground portion has a resistance ranging from 0.1 to 1000mΩ.
5. The apparatus of claim 1, wherein the grounding means is disposed in a cover ring around the periphery of the electrostatic chuck.
6. The device of claim 5, wherein the material of the cover ring is at least one of the following materials: quartz, aluminum oxide, aluminum nitride, single crystal silicon, polycrystalline silicon, silicon carbide, silicon nitride, and silicon oxide.
7. The device of claim 5, wherein the grounding means is a plurality of grounding means.
8. The device of claim 7, wherein the grounding means are evenly distributed in the cover ring.
9. The apparatus of claim 5, wherein the ground portion is a metal screw, the metal screw includes a stem and a head, the top portion covers the head of the metal screw, the stem of the metal screw is connected to a ground line through the cover ring, and the top portion is exposed to a surface of the cover ring facing the plasma.
10. The apparatus of claim 5, wherein a focus ring is further formed between the electrostatic chuck and the cover ring.
11. A device according to any one of claims 1-3, wherein the top portion is connected to an upper electrode and the ground portion is connected to ground.
12. A plasma processing apparatus, comprising: an upper plate and a wafer clamping device as claimed in any one of claims 1 to 11;
the wafer clamping device is used for fixing a wafer; when plasma is formed between the upper polar plate and the wafer, the plasma is used for processing the wafer.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911168656.3A CN112838040B (en) | 2019-11-25 | 2019-11-25 | Wafer clamping device and plasma processing equipment |
| TW109133985A TWI777256B (en) | 2019-11-25 | 2020-09-30 | Wafer Holders and Plasma Processing Equipment |
| KR1020200146887A KR102403938B1 (en) | 2019-11-25 | 2020-11-05 | Wafer clamping apparatus and plasma processing equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201911168656.3A CN112838040B (en) | 2019-11-25 | 2019-11-25 | Wafer clamping device and plasma processing equipment |
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| CN112838040A CN112838040A (en) | 2021-05-25 |
| CN112838040B true CN112838040B (en) | 2023-10-20 |
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| KR (1) | KR102403938B1 (en) |
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Also Published As
| Publication number | Publication date |
|---|---|
| CN112838040A (en) | 2021-05-25 |
| TWI777256B (en) | 2022-09-11 |
| TW202121579A (en) | 2021-06-01 |
| KR20210065037A (en) | 2021-06-03 |
| KR102403938B1 (en) | 2022-05-31 |
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