Electrostatic chuck with ceramic coating adhesion

Abstract

An electrostatic chuck is provided. The base plate comprises a conductive body. Multiple gas passages are located within the base plate. Multiple porous ceramic plugs are provided, each porous ceramic plug extending from a first surface of the base plate to a first end of the gas passage, and each of the multiple porous ceramic plugs has a first end adjacent to the first surface and a second end displaced from the first surface. Multiple ceramic plug coatings are located on the sides of the multiple porous ceramic plugs, and the ceramic plug coatings have a lower porosity than the porous ceramic plugs, and the combination of porous ceramic plugs and ceramic plug coatings forms a flange. The ceramic coatings are located on at least a first surface of the base plate.

Description

Technical Field

[0004]

[0001] Cross - reference to Related Applications This application claims the benefit of priority of U.S. Patent Application No. 63 / 519,979, filed on August 16, 2023, which is hereby incorporated by reference in its entirety for all purposes.

Background Art

[0002] This disclosure relates to an apparatus for processing a substrate. More specifically, this disclosure relates to an apparatus for plasma - processing a substrate.

Summary of the Invention

Problems to be Solved by the Invention

[0003] In various plasma - processing chambers, helium (He) is flowed over the backside of a substrate on an electrostatic chuck (ESC) to provide temperature control. The radio - frequency (RF) power used to form the plasma can cause secondary plasma emission within the ESC cavity due to the high voltages associated with plasma formation. Emission promotes arc discharge between any two surfaces having a high potential difference therebetween. Such arc discharges can damage the ESC. A ceramic plug is provided to reduce arc discharges. A ceramic coating is provided to protect the base plate of the ESC.

Means for Solving the Problems

[0004] To achieve the above and in accordance with the purposes of this disclosure, an electrostatic chuck is provided. The base plate comprises a conductive body. Multiple gas passages are located within the base plate. Multiple porous ceramic plugs are provided, each porous ceramic plug extending from a first surface of the base plate to a first end of one of the gas passages, and each of the multiple porous ceramic plugs has a first end adjacent to the first surface and a second end displaced from the first surface. Multiple ceramic plug coatings are located on the sides of the multiple porous ceramic plugs, and each porous ceramic plug has a ceramic plug coating of the multiple ceramic plug coatings, the ceramic plug coatings having a porosity lower than that of the porous ceramic plugs, and the combination of porous ceramic plugs and ceramic plug coatings forms a flange such that the diameter of the combination of porous ceramic plugs and ceramic plug coatings at the second end of the porous ceramic plug is smaller than the diameter of the combination of porous ceramic plugs and ceramic plug coatings between the first and second ends of the porous ceramic plug. The ceramic coatings are located on at least a first surface of the base plate.

[0005] In another embodiment, an electrostatic chuck is provided. The base plate comprises a conductive body. Multiple gas passages are located within the base plate. Multiple porous ceramic plugs are provided, each of which extends from a first surface of the base plate to a first end of one of the gas passages, and each of which has a first end adjacent to the first surface and a second end displaced from the first surface. Multiple ceramic plug coatings are located on the sides of the multiple porous ceramic plugs, and each of which has a ceramic plug coating, the ceramic plug coating having a lower porosity than the porous ceramic plug. Multiple adhesive coatings are provided, each of which lies between the ceramic plug coating and the base plate. The ceramic coatings are located on at least a first surface of the base plate.

[0006] In another embodiment, an electrostatic chuck is provided. The base plate comprises a conductive body. Multiple gas passages are located within the base plate. Multiple porous ceramic plugs are provided, each of which extends from a first surface of the base plate to a first end of one of the gas passages, and each of which has a first end adjacent to the first surface and a second end displaced from the first surface. Multiple ceramic plug coatings are provided on the sides of the multiple porous ceramic plugs, and each of which has a ceramic plug coating, the ceramic plug coating having a lower porosity than the porous ceramic plug. Multiple expansion washers are provided, each of which is located between a second end of one of the multiple porous ceramic plugs and the base plate. The ceramic coating is located on at least a first surface of the base plate.

[0007] In another embodiment, an electrostatic chuck is provided. The base plate comprises a conductive body. Multiple gas passages are located within the base plate. Multiple porous ceramic plugs are provided, each porous ceramic plug extending from a first surface of the base plate to a first end of one of the gas passages, and each porous ceramic plug having a first end adjacent to the first surface and a second end displaced from the first surface. Multiple ceramic plug coatings are located on the sides of the multiple porous ceramic plugs, and each porous ceramic plug has a ceramic plug coating of the multiple ceramic plug coatings, the ceramic plug coatings having a porosity lower than that of the porous ceramic plugs. The ceramic coatings are located on at least a first surface of the base plate, and a portion of the ceramic coatings on the first surface of the base plate has a thickness ranging from 100 μm to 550 μm, while a portion of the ceramic coatings on at least a first surface of the base plate has a thickness greater than 1200 μm.

[0008] In another embodiment, an electrostatic chuck is provided. The base plate comprises a conductive body. Multiple gas passages are located within the base plate. Multiple porous ceramic plugs are provided, each porous ceramic plug extending from a first surface of the base plate to a first end of one of the gas passages, each porous ceramic plug having a first end adjacent to the first surface and a second end displaced from the first surface, and each porous ceramic plug having a thickness in the range of 0.5 mm to 2 mm. Multiple ceramic plug coatings are located on the sides of the multiple porous ceramic plugs, and each porous ceramic plug has a ceramic plug coating of the multiple ceramic plug coatings, the ceramic plug coatings having a porosity lower than that of the porous ceramic plugs. The ceramic coatings are located on at least a first surface of the base plate.

[0009] In another embodiment, an electrostatic chuck is provided. The base plate comprises a conductive body. Multiple gas passages are located within the base plate. Multiple porous ceramic plugs are provided, each of which extends from a first surface of the base plate to a first end of one of the gas passages, and each of which has a first end adjacent to the first surface and a second end displaced from the first surface. Multiple ceramic plug coatings are located on the sides of the multiple porous ceramic plugs, and each of which has a ceramic plug coating, the ceramic plug coating having a lower porosity than the porous ceramic plug. The ceramic coatings are located on at least a first surface of the base plate, and the ceramic coatings extend between the multiple ceramic plug coatings and the base plate.

[0010] In another embodiment, an electrostatic chuck is provided. The base plate comprises a conductive body. Multiple gas passages are located within the base plate. The base plate has multiple plug holes, and the edges of each plug hole on the surface of the base plate are chamfered. An anodized layer is located on the surface of the base plate and does not extend over the chamfered portions of the plug holes. Multiple porous ceramic plugs are provided, each of the multiple porous ceramic plugs located within the plug holes of the multiple plug holes. Multiple ceramic plug coatings are located on the sides of the multiple porous ceramic plugs, and each of the multiple porous ceramic plugs has a ceramic plug coating of the multiple ceramic plug coatings. The ceramic coating is located on at least a first surface of the base plate, and the anodized layer is located between the ceramic coating and the surface of the base plate.

[0011] In another embodiment, an electrostatic chuck is provided. The base plate comprises a conductive body. Multiple gas passages are located within the base plate. The base plate has multiple plug holes, and the edges of each plug hole on the surface of the base plate are chamfered. Multiple porous ceramic plugs are provided, each of the multiple porous ceramic plugs is located within the plug holes of the multiple plug holes. Multiple ceramic plug coatings are located on the sides of the multiple porous ceramic plugs, and each of the multiple porous ceramic plugs has a ceramic plug coating of the multiple ceramic plug coatings, and the multiple porous ceramic plugs and the multiple ceramic plug coatings do not come into contact with the base plate. The ceramic coatings are located on at least a first surface of the base plate.

[0012] In another embodiment, an electrostatic chuck is provided. The base plate comprises a conductive body. The base plate is provided with a plurality of gas passages. The base plate has a plurality of plug holes, and the edges of each plug hole on the surface of the base plate are chamfered and laser-cut. A plurality of porous ceramic plugs are provided, each porous ceramic plug of the plurality of porous ceramic plugs is located in the plug holes of the plurality of plug holes. A plurality of ceramic plug coatings are on the sides of the plurality of porous ceramic plugs, and each porous ceramic plug of the plurality of porous ceramic plugs has a ceramic plug coating of the plurality of ceramic plug coatings. The ceramic coatings are on at least a first surface of the base plate.

[0013] These and other features of this disclosure will be described in more detail in the following detailed description, in conjunction with the following drawings.

[0014] This disclosure is shown as an example, not as an limitation, in the figures of the attached drawings, where similar reference numbers refer to similar elements. [Brief explanation of the drawing]

[0015] [Figure 1] Schematic cross-sectional view of a base plate of an electrostatic chuck (ESC) that can be used in one embodiment. [Figure 2] Schematic cross-sectional view of an enlarged portion of a base plate that can be used in the prior art. [Figure 3A] Schematic cross-sectional view of an enlarged portion of a base plate that can be used in some embodiments. [Figure 3B] Schematic cross-sectional view of an enlarged portion of a base plate that can be used in some embodiments. [Figure 3C] Schematic cross-sectional view of an enlarged portion of a base plate that can be used in some embodiments. [Figure 3D] Schematic cross-sectional view of an enlarged portion of a base plate that can be used in some embodiments. [Figure 3E] Schematic cross-sectional view of an enlarged portion of a base plate that can be used in some embodiments. [Figure 3F] Schematic cross-sectional view of an enlarged portion of a base plate that can be used in some embodiments. [Figure 3G] Schematic cross-sectional view of an enlarged portion of a base plate that can be used in some embodiments. [Figure 3H] Schematic cross-sectional view of an enlarged portion of a base plate that can be used in some embodiments. [Figure 3I] Schematic cross-sectional view of an enlarged portion of a base plate that can be used in some embodiments. <I [Figure 3J] Schematic cross-sectional view of an enlarged portion of a base plate that can be used in some embodiments. [Figure 4] Schematic cross-sectional view of a part of an ESC that can be used in one embodiment. [Figure 5] Schematic view of a processing chamber that can be used in one embodiment.

MODE FOR CARRYING OUT THE INVENTION

[0016] In the drawings, like reference numerals may be used to indicate like structural elements. It is also to be understood that the depictions in the figures are schematic and not to scale.

[0017] This disclosure will be described in detail with reference to several of its embodiments as shown in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of this disclosure. However, it will be apparent to those skilled in the art that this disclosure may be practiced without some or all of these specific details. In other instances, well-known process steps and / or structures have not been described in detail so as not to unnecessarily obscure this disclosure.

[0018] The new semiconductor manufacturing process requires very high RF power plasma. Increasing the RF power increases the RF current and total voltage applied to the electrostatic chuck (ESC - wafer susceptor). At the same time, the new plasma etching process requires a significantly lower RF frequency (e.g., 2 MHz, 400 kHz, or less) than previously required. The low RF frequency causes a further increase in the RF voltage applied to the ESC ceramic. When a high voltage is applied across the ceramic, there may be a discharge (arc discharge) between the wafer and the base plate or the heat transfer gas (e.g., He) may ignite (luminescence) within the gas supply holes. Arc discharge of the ESC usually causes catastrophic destruction of components accompanied by wafer breakage, possible damage to other chamber components, and interruption of the manufacturing process. In the case of luminescence of the heat transfer gas, the destruction of the ESC may be catastrophic or may develop slowly to affect multiple wafers with damage to the semiconductor devices and be detected only at much later steps of the manufacturing process. In either case, the failure of the ESC results in significant losses to wafer production and the manufacturer's revenue.

[0019] Some ESCs (Electromagnetic Sensors) have a conductive base plate beneath an electrically insulating ceramic plate. A bonding layer can be used to attach the base plate to the ceramic plate. The heat transfer path can pass through the base plate, the bonding layer, and the ceramic plate.

[0020] In low-voltage applications, it is common to obstruct the line of sight using the holes in the ceramic plate and the ceramic sleeve of the base plate facing the holes in the ceramic plate. In low-to-medium voltage applications, the ceramic sleeve of the base plate is replaced with a porous plug that provides a higher voltage rating than the ceramic sleeve. In medium-voltage applications, in addition to the sleeve of the base plate, a porous plug is inserted into the ceramic plate.

[0021] One embodiment provides a solution to the problems of arc discharge and He emission in ESCs by introducing a plug (made of ceramic material, e.g., alumina Al2O3 or aluminum nitride AlN) having a small opening (0.1 to 100 micrometers in diameter) into the He hole. The plug compartmentalizes the He hole volume into smaller minute volumes that limit the probability of emission. This probability is limited by reducing the number of charged particle collisions and preventing line of sight between the wafer and the metal parts of the chuck below the upper ceramic plate. The necessary He flows through the hole to maintain backside cooling of the wafer.

[0022] For ease of understanding, Figure 1 is a schematic cross-sectional view of a portion of a base plate 104 used in several embodiments. The base plate 104 comprises a conductor having a plurality of gas passages 108, each having a plurality of porous ceramic plugs 112 at the ends of the gas passages 108. The ceramic coating 116 is on the surface of the first side of the base plate 104.

[0023] Figure 2 is an enlarged schematic cross-sectional view of a portion of the base plate 104 and porous ceramic plug 112, shown as Region II used in the prior art. The porous ceramic plug 112 has a porosity in the range of 10% to 80% by volume to allow gas to pass through the porous ceramic plug 112 while reducing arc discharge. In some embodiments, the porous ceramic plug 112 has a porosity in the range of 20% to 70%. In some embodiments, the porous ceramic plug 112 has a pore diameter in the range of 10 μm to 500 μm. The ceramic plug coating 204 is located between the porous ceramic plug 112 and the base plate 104. The ceramic plug coating 204 may be spray-coated onto the sides of the porous ceramic plug 112. The ceramic plug coating 204 is less porous than the porous ceramic plug 112, and as a result, the ceramic plug coating 204 is more resistant to arc discharge from the base plate 104 than the porous ceramic plug 112. In some embodiments, the ceramic plug coating 204 has a porosity in the range of less than 5%. In some embodiments, the ceramic plug coating 204 has a porosity of less than 1%. In some embodiments, the ceramic plug coating 204 has a porosity of less than 0.5%. To allow gas to flow from the gas manifold 208 through the porous ceramic plug 112, the ceramic plug coating 204 may not be present between the base plate 104 and the porous ceramic plug 112 near the first side surface of the base plate 104. The outer upper edge of the porous ceramic plug 112 and the ceramic plug coating 204 are chamfered as shown. The corners of the base plate 104 surrounding the hole for arranging the porous ceramic plug 112 are also chamfered. The chamfered corners allow for angled spray deposition of the ceramic coating 116 to enhance adhesion of the ceramic coating 116. The chamfered corners also displace the top of the ceramic plug coating 204 from the top of the ceramic coating 116 to enhance adhesion of the ceramic coating 116.The majority of the ceramic coating 116 has a thickness ranging from 100 μm to 550 μm. The thickness of the ceramic coating 116 at the chamfered corners ranges from 500 μm to 1000 μm. The gas manifold 208 between the gas passage 108 and the porous ceramic plug 112 allows a larger surface area of ​​the porous ceramic plug 112 to be exposed to the temperature-controlled gas.

[0024] During operation, the base plate 104 may be cooled to a temperature below 0°C. Cooling of the base plate 104 causes the metal base plate 104 to contract vertically more than the porous ceramic plug 112, creating stress in the ceramic coating 116. The difference in the coefficient of thermal expansion (CTE) between the metal base plate 104 and the porous ceramic plug 112 across the entire depth of the porous ceramic plug 112 beneath the ceramic coating 116 creates stress in the ceramic coating 116. This stress in the ceramic coating 116 can cause cracking and / or delamination, leading to leakage of heat transfer gases and reducing the lifespan of the ESC. Reducing the stress on the ceramic coating 116 will extend the lifespan of the ESC.

[0025] Figure 3A is an enlarged schematic cross-sectional view of a portion of the base plate 104 and the porous ceramic plug 112, shown as region II used in some embodiments. The porous ceramic plug 112 has a first end 320 adjacent to the first surface of the base plate 104 and a second end 324 positioned at a distance from the first end 320 and the first surface of the base plate 104. The ceramic plug coating 304 has a thicker flange portion 308 closer to the first end 320 of the porous ceramic plug 112 than to the second end 324 of the porous ceramic plug 112. The flange portion 308 causes the porous ceramic plug 112 and the ceramic plug coating 304 to flange such that the diameter of the porous ceramic plug 112 and the ceramic plug coating 304 combination at the second end 324 of the porous ceramic plug 112 is smaller than the diameter of the porous ceramic plug 112 and the ceramic plug coating 304 combination between the first end 320 and the second end 324 of the porous ceramic plug 112. If the porous ceramic plug 112 is not chamfered, the flange portion 308 extends to the first end 320 of the porous ceramic plug 112. The portion of the porous ceramic plug 112 and the ceramic plug coating 304 below the thickest part of the ceramic coating 116 have a reduced depth D compared to the depth of the thickest part of the porous ceramic plug 112.

[0026] During operation, the base plate 104 may be cooled to a temperature below 0°C. Cooling of the base plate 104 causes the metal base plate 104 to contract vertically more than the porous ceramic plug 112, generating stress in the ceramic coating 116. The flange portion 308 reduces the vertical depth D of the ceramic plug coating 304 located beneath the thickest part of the ceramic coating 116. By reducing this vertical depth D, only the mismatch in CTE of the base plate 104 and the ceramic plug coating 304 with respect to depth D generates stress in the thickest part of the ceramic coating 116. As a result, the stress in the thickest part of the ceramic coating 116 is reduced compared to the prior art.

[0027] Figure 3B is an enlarged schematic cross-sectional view of a portion of the base plate 104 and the porous ceramic plug 112, shown as region II used in some embodiments. The porous ceramic plug 112 has a first end 320 adjacent to the first surface of the base plate 104 and a second end 324 positioned at a distance from the first end 320 and the first surface of the base plate 104. The porous ceramic plug 112 has a thicker flange portion 332 closer to the first end 320 than to the second end 324. The flange portion 332 causes the porous ceramic plug 112 and the ceramic plug coating 304 to flange such that the diameter of the porous ceramic plug 112 and the ceramic plug coating 304 combination at the second end 324 is smaller than the diameter of the porous ceramic plug 112 and the ceramic plug coating 304 combination between the first end 320 and the second end 324. If the porous ceramic plug 112 is not chamfered, the flange portion 332 extends to the first end 320 of the porous ceramic plug 112. The portion of the porous ceramic plug 112 and the ceramic plug coating 304 below the thickest part of the ceramic coating 116 have a reduced depth D compared to the depth of the thickest part of the porous ceramic plug 112.

[0028] During operation, the base plate 104 may be cooled to a temperature below 0°C. Cooling of the base plate 104 causes the metal base plate 104 to contract vertically more than the porous ceramic plug 112, generating stress in the ceramic coating 116. The flange portion 332 reduces the vertical depth D of the porous ceramic plug 112 and ceramic plug coating 304 located beneath the thickest part of the ceramic coating 116. By reducing this vertical depth D, only the mismatch in CTE of the base plate 104 and the porous ceramic plug 112 with respect to depth D generates stress in the ceramic coating 116 at its thickest point. As a result, the stress in the thickest part of the ceramic coating 116 is reduced compared to the prior art.

[0029] Figure 3C is an enlarged schematic cross-sectional view of a portion of the base plate 104 and porous ceramic plug 112, shown as region II used in some embodiments. The porous ceramic plug 112 has a first end 320 adjacent to the first surface of the base plate 104 and a second end 324 positioned at a distance from the first end 320 and the first surface of the base plate 104. An adhesive coating 340 is positioned around the ceramic plug coating 304 near the second end 324 of the porous ceramic plug 112. In some embodiments, the adhesive coating 340 is formed from an adhesive which is at least one of a silicone bond and / or epoxy.

[0030] During operation, the base plate 104 may be cooled to a temperature below 0°C. Cooling of the base plate 104 causes the metal base plate 104 to contract vertically more than the porous ceramic plug 112, creating stress on the ceramic coating 116. The adhesive moves the base plate 104 and the porous ceramic plug 112 together. The adhesive also causes the porous ceramic plug 112 to retract vertically together with the base plate 104. As a result, the stress on the ceramic coating 116 is reduced compared to the prior art.

[0031] Figure 3D is an enlarged schematic cross-sectional view of a portion of a porous ceramic plug 112, including a base plate 104 and a ceramic plug coating 304, shown as region II used in some embodiments. The porous ceramic plug 112 has a first end 320 adjacent to the first surface of the base plate 104 and a second end 324 positioned at a distance from the first end 320 and the first surface of the base plate 104. A CTE washer 348 (expansion washer) has a first side positioned relative to the second end 324 of the porous ceramic plug 112 and the ceramic plug coating 304. The second side of the CTE washer 348, opposite to the first side, is positioned in contact with the base plate 104. As a result, the CTE washer 348 is located between the second end 324 of the porous ceramic plug 112 and / or the ceramic plug coating 304 and the base plate 104. In some embodiments, the CTE washer 348 has a larger CTE than the porous ceramic plug 112 and the ceramic plug coating 304. In some embodiments, the CTE washer 348 has a larger CTE than the base plate 104, and the CTE of the base plate 104 is larger than the CTE of the porous ceramic plug 112 and the ceramic plug coating 304. This allows the larger CTE of the CTE washer 348 to compensate for the lower CTE of the porous ceramic plug 112 and the ceramic plug coating 304.In some embodiments, the combination of the height (H1) of the CTE washer 348, the height (H2) of the base plate 104 adjacent to the CTE washer 348 and the ceramic plug coating 304, and the height (H3) of the porous ceramic plug 112 or ceramic plug coating 304 on the CTE washer 348 can be adjusted such that the value obtained by multiplying the CTE of the base plate 104 by the height (H2) of the base plate 104 is approximately equal to the value obtained by multiplying the height (H3) of the porous ceramic plug 112 or ceramic plug coating 304 by the CTE of the porous ceramic plug 112 or ceramic plug coating 304, plus the value obtained by multiplying the height (H1) of the CTE washer 348 by the CTE of the CTE washer 348. In some embodiments, the values ​​are approximately equal if they are within 10% of each other. In some embodiments, the sum of the height (H1) of the CTE washer 348 and the height (H3) of the porous ceramic plug 112 or ceramic plug coating 304 on top of the CTE washer 348 is approximately equal to the height (H2) of the base plate 104 adjacent to the CTE washer 348 and ceramic plug coating 304. In some embodiments, the CTE washer 348 contains a polymer. In some embodiments, the polymer is a fluoropolymer such as polytetrafluoroethylene (PTFE), e.g., Teflon®, perfluoroalkoxyalkane (PFA), polyetherimide, and polyetheretherketone (PEEK). In some embodiments, the CTE washer 348 is located beneath the thickest portion of the ceramic coating 116.

[0032] During operation, the base plate 104 may be cooled to a temperature below 0°C. Cooling of the base plate 104 causes the metal base plate 104 to contract vertically more than the porous ceramic plug 112, generating stress on the ceramic coating 116. Since the CTE of the CTE washer 348 is greater than the CTE of the porous ceramic plug 112, the difference in CTE is reduced. The CTE washer 348 may also act as a cushion to reduce the vertical movement of the first end 320 of the porous ceramic plug 112 relative to the first surface. As a result, the stress on the ceramic coating 116 is reduced compared to the prior art.

[0033] Figure 3E is an enlarged schematic cross-sectional view of a portion of the base plate 104 and porous ceramic plug 112, shown as region II used in some embodiments. In some embodiments, the chamfered portions of the porous ceramic plug 112 and base plate 104 are deeper. The deeper chamfered portions result in a thickness T of the ceramic coating 116 greater than 1200 μm at the chamfered portion. The thickness of the ceramic coating 116 at other locations on the surface of the base plate 104 is in the range of 100 μm to 550 μm. In some embodiments, when the ceramic coating extends to each porous ceramic plug or ceramic plug coating 304 of a plurality of porous ceramic plugs, the ceramic coating has a thickness T greater than 1200 μm, as shown in Figure 3E.

[0034] During operation, the base plate 104 may be cooled to a temperature below 0°C. Cooling of the base plate 104 causes the metal base plate 104 to contract vertically more than the porous ceramic plug 112, creating stress on the ceramic coating 116. By increasing the thickness of the ceramic coating 116 around the porous ceramic plug 112, the ceramic coating 116 becomes stronger around the porous ceramic plug 112. A stronger ceramic coating 116 reduces cracking and extends the lifespan of the base plate 104.

[0035] Figure 3F is an enlarged schematic cross-sectional view of a portion of the base plate 104 and the porous ceramic plug 112, shown as region II used in some embodiments. In some embodiments, the porous ceramic plug 112 has a depth D in the range of 0.5 mm to 2.0 mm. In some embodiments, the porous ceramic plug 112 has a depth of less than half that of the porous ceramic plugs used in the prior art. The reduced depth of the porous ceramic plug 112 indicates an increased electric field between the back of the porous ceramic plug 112 and the base plate 104, posing a potential risk of arc discharge. The ceramic plug coating 304 extends to the back of the porous ceramic plug 112 to prevent arc discharge between the back of the porous ceramic plug 112 and the base plate 104.

[0036] During operation, the base plate 104 may be cooled to a temperature below 0°C. Cooling of the base plate 104 causes the metal base plate 104 to contract vertically more than the porous ceramic plug 112, creating stress on the ceramic coating 116. Since the thickness of the porous ceramic plug 112 is much smaller than half the thickness of porous ceramic plugs 112 used in the prior art, the stress on the ceramic coating 116 is reduced.

[0037] Figure 3G is an enlarged schematic cross-sectional view of a portion of the base plate 104 and the porous ceramic plug 112, shown as region II used in some embodiments. The porous ceramic plug 112 has a first end 320 adjacent to the first surface of the base plate 104. The second end 324 of the porous ceramic plug 112 is positioned at a distance from the first end 320 and the first surface of the base plate 104. Instead of the first end 320 of the porous ceramic plug 112 being chamfered, the first end 320 of the porous ceramic plug is funnel-shaped, and as a result, the first end 320 of the porous ceramic plug 112 has the widest diameter, tapering toward the second end 324 of the porous ceramic plug 112. In some embodiments, at a certain point, the tapering shape causes the porous ceramic plug 112 to reach a minimum diameter between the first end 320 and the second end 324, and the diameter remains constant toward the second end 324 of the porous ceramic plug 112, as shown. In contrast to some other embodiments in which the porous ceramic plug 112 and ceramic plug coating 304 extend beneath the ceramic coating 116, the porous ceramic plug 112 and ceramic plug coating 304 extend above the ceramic coating 116.

[0038] During operation, the base plate 104 may be cooled to a temperature below 0°C. Cooling of the base plate 104 causes the metal base plate 104 to contract vertically more than the porous ceramic plug 112. Since the ceramic coating 116 is located beneath the porous ceramic plug 112 and the ceramic plug coating 304, the porous ceramic plug 112 and the ceramic plug coating 304 do not impose stress on the ceramic coating 116.

[0039] Figure 3H is an enlarged schematic cross-sectional view of a portion of the base plate 104 and porous ceramic plug 112, shown as region II used in some embodiments. The porous ceramic plug 112 has a first end 320 adjacent to the first surface of the base plate 104 and a second end 324 positioned at a distance from the first end 320 and the first surface of the base plate 104. The anodized layer 330 is located between the first surface of the base plate 104 and the ceramic coating 116. The anodized layer 330 is removed where the base plate 104 is chamfered. Removing the anodized layer 330 where the base plate 104 is chamfered improves the adhesion of the ceramic coating 116 to the base plate 104 over the chamfer. This embodiment may be combined with other embodiments.

[0040] Figure 3I is an enlarged schematic cross-sectional view of a portion of the base plate 104 and the porous ceramic plug 112, shown as region II used in some embodiments. The porous ceramic plug 112 has a first end 320 adjacent to the first surface of the base plate 104 and a second end 324 positioned at a distance from the first end 320 and the first surface of the base plate 104. In this embodiment, the porous ceramic plug 112 is not chamfered. Instead, the porous ceramic plug 112 and the ceramic plug coating 304 form a cylindrical shape. The ceramic coating 116 and an adhesive 362 such as epoxy hold the porous ceramic plug 112 and the ceramic plug coating 304 in place. In some embodiments, the porous ceramic plug 112 and the ceramic plug coating 304 do not contact the base plate 104. The base plate 104 has a space 364 formed by plug holes. The space is between the base plate 104 and the porous ceramic plug 112.

[0041] During operation, the base plate 104 may be cooled to a temperature below 0°C. Cooling of the base plate 104 causes the metal base plate 104 to contract vertically more than the porous ceramic plug 112. Since the ceramic coating 116 is not on top of the porous ceramic plug 112 and the ceramic plug coating 304, the porous ceramic plug 112 and the ceramic plug coating 304 do not impart stress to the ceramic coating 116. Furthermore, since the porous ceramic plug 112 and the ceramic plug coating 304 do not come into direct contact with the base plate 104, stress is further reduced.

[0042] Figure 3J is an enlarged schematic cross-sectional view of a portion of the base plate 104 and the porous ceramic plug 112, shown as region II used in some embodiments. The porous ceramic plug 112 has a first end 320 adjacent to the first surface of the base plate 104 and a second end 324 positioned at a distance from the first end 320 and the first surface of the base plate 104. In this embodiment, the porous ceramic plug 112 is not chamfered. Instead, the porous ceramic plug 112 forms a cylindrical shape. The ceramic plug coating 304 has a larger diameter at the first end 320 than at the second end 324 which forms a counter-sink for the chamfered hole in the base plate 104. The porous ceramic plug 112 and the ceramic plug coating 304 are placed in the hole such that a portion of the ceramic plug coating 304 is on top of a portion of the ceramic coating 116. An adhesive 366, such as epoxy, can be placed between the ceramic plug coating 304 and the portion of the ceramic coating 116. In some embodiments, the porous ceramic plug 112 and the ceramic plug coating 304 do not come into contact with the base plate 104, but instead have a space 368 between the base plate 104 and the porous ceramic plug 112.

[0043] During operation, the base plate 104 may be cooled to a temperature below 0°C. Cooling of the base plate 104 causes the metal base plate 104 to contract vertically more than the porous ceramic plug 112. Since the ceramic coating 116 is not on top of the porous ceramic plug 112 and the ceramic plug coating 304, the porous ceramic plug 112 and the ceramic plug coating 304 do not impart stress to the ceramic coating 116. Furthermore, stress is further reduced because the porous ceramic plug 112 and the ceramic plug coating 304 do not directly contact the base plate 104. The countersink shape of the ceramic plug coating 304 allows the ceramic plug coating 304 and the porous ceramic plug 112 to be installed within the base plate 104 without contact with the base plate 104. In some embodiments, the porous ceramic plug 112 forms a countersink shape.

[0044] In some embodiments, the chamfered surface of the base plate 104 is laser-processed to improve adhesion between the ceramic coating 116 and the chamfered surface of the base plate 104. Laser processing of the chamfered surface helps prevent the ceramic coating 116 from peeling off the chamfered surface of the base plate.

[0045] In some embodiments, the base plate 104 is bonded to the ceramic plate by a bonding layer. Figure 4 is a schematic cross-sectional view of the base plate 104 having a porous ceramic plug 112 and a gas passage 108. The bonding layer 404 bonds the base plate 104 to the ceramic plate 408. In some embodiments, the ceramic plate plug 412 is located within the ceramic plate 408 adjacent to the heat transfer gas pores 416. In some embodiments, the plenum 420 is located within the bonding layer 404 between the porous ceramic plug 112 and the ceramic plate plug 412. In some embodiments, the ceramic plate plug 412 is a multi-tube lumen plug. Several embodiments can provide different ceramic plate plugs 412.

[0046] Figure 5 is a schematic diagram of one embodiment of a semiconductor processing chamber 500 that may be used to process semiconductor wafers. In one or more embodiments, the semiconductor processing chamber 500 comprises a gas distribution plate 506 providing a gas inlet and an electrostatic chuck (ESC) 508 within an etching chamber 549 surrounded by chamber walls 552. Within the etching chamber 549, a wafer 503 is placed on the ESC 508, which is a wafer support. An edge ring 509 surrounds the ESC 508. An ESC source 548 can provide a bias to the ESC 508. A gas source 510 is connected to the etching chamber 549 via the gas distribution plate 506. An ESC heat transfer gas source 550 is connected to the ESC 508.

[0047] The radio frequency (RF) source 530 supplies RF power to the lower electrode, the upper outer electrode 516, and the upper inner electrode. In this embodiment, the ESC 508 is the lower electrode and the gas distribution plate 506 is the upper inner electrode. In an exemplary embodiment, power supplies of 400 kHz, 60 MHz, 2 MHz, 13.56 MHz, and / or 27 MHz constitute the RF source 530 and the ESC source 548. In this embodiment, one generator is provided for each frequency. In other embodiments, the generators may be separate RF sources, or the separate RF generators may be connected to different electrodes. In other embodiments, other arrangements of RF sources and electrodes may be used. In other embodiments, the electrodes may be induction coils.

[0048] The controller 535 is controllably connected to the RF source 530, the ESC source 548, the exhaust pump 520, and the gas source 510. The high-flow liner 504 is a liner within the etching chamber 549. In this embodiment, the high-flow liner 504 is a C-shroud that confines gas from the gas source and has slots 502. The high-flow liner 504 allows a controlled gas flow to pass from the gas source 510 to the exhaust pump 520.

[0049] During processing, heat transfer gas can be supplied from the ESC heat transfer gas source 550 to the back of the ESC 508 to provide heat transfer. The RF source 530 supplies power to form the plasma. The plasma may cause an arc discharge. The arc discharge may travel towards the heat transfer gas source and damage the ESC 508.

[0050] Although only a single porous ceramic plug having a ceramic plug coating and an adhesive coating is shown, some embodiments utilize multiple porous ceramic plugs, each porous ceramic plug having multiple ceramic plug coatings. In some embodiments, each porous ceramic plug may have a gas passage and an expansion washer (CTE washer) or an adhesive coating.

[0051] While this disclosure describes several embodiments, there are many variations, modifications, substitutions, and various alternative equivalents that fall within the scope of this disclosure. It should also be noted that there are many alternative ways of implementing the methods and apparatus of this disclosure. Therefore, the following appended claims are intended to be interpreted as including all such variations, modifications, substitutions, and various alternative equivalents that fall within the true spirit and scope of this disclosure. Where used in this disclosure, the phrase “A, B, or C” should be interpreted as meaning a logic using the non-exclusive logic “OR” (“A OR B OR C”) and not as meaning “only one of A, B, or C”. Each step in the process may be an optional step and is not mandatory. Different embodiments may have one or more steps omitted, or may provide steps in a different order. Furthermore, different embodiments may provide different steps simultaneously rather than sequentially. [Explanation of symbols]

[0052] 104 Base Plate 104 Metal base plate 108 Gas passage 112 Porous ceramic plug 116 Ceramic Coating 204 Ceramic Plug Coating 208 Gas Manifold 304 Ceramic Plug Coating 308 Flange section 320 End 324 End 330 Anodized layer 332 Flange section 340 Adhesive Coating 348 CTE Washer 362 Adhesives 364 Space 366 Adhesive 368 Space 404 Connecting layer 408 Ceramic Plate 412 Ceramic Plate Plug 416 Heat transfer gas holes 420 Plenum 500 Semiconductor Processing Chambers 502 slots 503 wafer 504 High-flow liner 506 Gas Distribution Plate 509 Edge Ring 510 Gas source 516 Upper outer electrode 520 Exhaust pump 530 Radio Radio Frequency (RF) Source 530 RF source 535 Controller 548 ESC source 549 Etching Chamber 550 ESC Heat Transfer Gas Source 552 Chamber Wall

Claims

1. It is an electrostatic chuck, A base plate having a conductive body, Multiple gas passages within the base plate, A plurality of porous ceramic plugs, each of the plurality of porous ceramic plugs extending from a first surface of the base plate to a first end of the gas passage of the plurality of gas passages, and each of the plurality of porous ceramic plugs having a first end adjacent to the first surface and a second end displaced from the first surface, A plurality of ceramic plug coatings on the side surfaces of the plurality of porous ceramic plugs, wherein each of the plurality of porous ceramic plugs has a ceramic plug coating of the plurality of ceramic plug coatings, and the ceramic plug coating has a porosity lower than that of the porous ceramic plug, A plurality of expansion washers, each of the plurality of expansion washers is located between the second end of the porous ceramic plug or ceramic plug coating of the plurality of porous ceramic plugs and the base plate, An electrostatic chuck comprising a ceramic coating on at least the first surface of the base plate.

2. The electrostatic chuck according to claim 1, wherein the plurality of expansion washers have a coefficient of thermal expansion (CTE), the plurality of porous ceramic plugs have a CTE, and the CTE of the expansion washers is greater than the CTE of the plurality of porous ceramic plugs.

3. The electrostatic chuck according to claim 1, wherein the plurality of expansion washers have a coefficient of thermal expansion (CTE), the plurality of porous ceramic plugs have a CTE, the base plate has a CTE, and the CTE of the expansion washers is greater than the CTE of the plurality of porous ceramic plugs and the CTE of the base plate.

4. The bonding layer on the first surface of the base plate, wherein the base plate has a first side surface of the bonding layer, A ceramic plate on the second side surface of the bonding layer, The electrostatic chuck according to claim 1, further comprising:

5. The electrostatic chuck according to claim 1, wherein the ceramic coating extends to each of the plurality of porous ceramic plugs.

6. The electrostatic chuck according to claim 1, wherein the plurality of expansion washers include a polymer.

7. It is an electrostatic chuck, A base plate having a conductive body, Multiple gas passages within the base plate, A plurality of porous ceramic plugs, each of the plurality of porous ceramic plugs extending from a first surface of the base plate to a first end of the gas passage of the plurality of gas passages, and each of the plurality of porous ceramic plugs having a first end adjacent to the first surface and a second end displaced from the first surface, A plurality of ceramic plug coatings on the side surfaces of the plurality of porous ceramic plugs, wherein each of the plurality of porous ceramic plugs has a ceramic plug coating of the plurality of ceramic plug coatings, the ceramic plug coating has a porosity lower than the porosity of the porous ceramic plug, and the combination of the porous ceramic plug and the ceramic plug coating forms a flange such that the diameter of the combination of the porous ceramic plug and the ceramic plug coating at the second end of the porous ceramic plug is smaller than the diameter of the combination of the porous ceramic plug and the ceramic plug coating between the first end and the second end of the porous ceramic plug, An electrostatic chuck comprising a ceramic coating on at least the first surface of the base plate.

8. The electrostatic chuck according to claim 7, wherein the thickness of the ceramic plug coating at the second end of the porous ceramic plug is thinner than the thickness of the ceramic plug coating between the first end of the porous ceramic plug and the second end of the porous ceramic plug.

9. The electrostatic chuck according to claim 7, wherein the diameter of the porous ceramic plug at the second end of the porous ceramic plug is smaller than the diameter of the porous ceramic plug between the first end of the porous ceramic plug and the second end of the porous ceramic plug.

10. The bonding layer on the first surface of the base plate, wherein the base plate has a first side surface of the bonding layer, A ceramic plate on the second side surface of the bonding layer, The electrostatic chuck according to claim 7, further comprising:

11. The electrostatic chuck according to claim 7, wherein the ceramic coating extends to each of the plurality of porous ceramic plugs.

12. It is an electrostatic chuck, A base plate having a conductive body, Multiple gas passages within the base plate, A plurality of porous ceramic plugs, each of the plurality of porous ceramic plugs extending from a first surface of the base plate to a first end of the gas passage of the plurality of gas passages, and each of the plurality of porous ceramic plugs having a first end adjacent to the first surface and a second end displaced from the first surface, A plurality of ceramic plug coatings on the side surfaces of the plurality of porous ceramic plugs, wherein each of the plurality of porous ceramic plugs has a ceramic plug coating of the plurality of ceramic plug coatings, and the ceramic plug coating has a porosity lower than that of the porous ceramic plug, A plurality of adhesive coatings, wherein each of the plurality of adhesive coatings is a plurality of adhesive coatings located between the ceramic plug coating of the plurality of ceramic plug coatings and the base plate, An electrostatic chuck comprising a ceramic coating on at least the first surface of the base plate.

13. The electrostatic chuck according to claim 12, wherein each adhesive coating extends along the ceramic plug coating of the plurality of ceramic plug coatings adjacent to the second end of the plurality of porous ceramic plugs.

14. The bonding layer on the first surface of the base plate, wherein the base plate has a first side surface of the bonding layer, A ceramic plate on the second side surface of the bonding layer, The electrostatic chuck according to claim 12, further comprising:

15. The electrostatic chuck according to claim 14, wherein the ceramic coating extends to each of the plurality of porous ceramic plugs.

16. It is an electrostatic chuck, A base plate having a conductive body, Multiple gas passages within the base plate, A plurality of porous ceramic plugs, each of the plurality of porous ceramic plugs extending from a first surface of the base plate to a first end of the gas passage of the plurality of gas passages, and each of the plurality of porous ceramic plugs having a first end adjacent to the first surface and a second end displaced from the first surface, A plurality of ceramic plug coatings on the side surfaces of the plurality of porous ceramic plugs, wherein each of the plurality of porous ceramic plugs has a ceramic plug coating of the plurality of ceramic plug coatings, and the ceramic plug coating has a porosity lower than that of the porous ceramic plug, An electrostatic chuck comprising a ceramic coating on at least the first surface of the base plate, wherein a portion of the ceramic coating on the first surface of the base plate has a thickness in the range of 100 μm to 550 μm, and a portion of the ceramic coating on at least the first surface of the base plate has a thickness of more than 1200 μm.

17. The electrostatic chuck according to claim 16, wherein the ceramic coating has a thickness of more than 1200 μm on the ceramic plug coating.

18. The electrostatic chuck according to claim 16, wherein the ceramic coating extends to each of the multiple ceramic plug coatings, and the ceramic coating has a thickness of more than 1200 μm.

19. It is an electrostatic chuck, A base plate having a conductive body, Multiple gas passages within the base plate, A plurality of porous ceramic plugs, each of the plurality of porous ceramic plugs extending from a first surface of the base plate to a first end of the gas passage of the plurality of gas passages, each of the plurality of porous ceramic plugs having a first end adjacent to the first surface and a second end displaced from the first surface, and each porous ceramic plug having a thickness in the range of 0.5 mm to 2 mm, A plurality of ceramic plug coatings on the side surfaces of the plurality of porous ceramic plugs, wherein each of the plurality of porous ceramic plugs has a ceramic plug coating of the plurality of ceramic plug coatings, and the ceramic plug coating has a porosity lower than that of the porous ceramic plug, An electrostatic chuck comprising a ceramic coating on at least the first surface of the base plate.

20. The electrostatic chuck according to claim 19, wherein each ceramic plug coating extends between the second end of the porous ceramic plug and the base plate.

21. It is an electrostatic chuck, A base plate having a conductive body, Multiple gas passages within the base plate, A plurality of porous ceramic plugs, each of the plurality of porous ceramic plugs extending from a first surface of the base plate to a first end of the gas passage of the plurality of gas passages, and each of the plurality of porous ceramic plugs having a first end adjacent to the first surface and a second end displaced from the first surface, A plurality of ceramic plug coatings on the side surfaces of the plurality of porous ceramic plugs, wherein each of the plurality of porous ceramic plugs has a ceramic plug coating of the plurality of ceramic plug coatings, and the ceramic plug coating has a porosity lower than that of the porous ceramic plug, An electrostatic chuck comprising a ceramic coating on at least the first surface of the base plate, the ceramic coating extending between the plurality of ceramic plug coatings and the base plate.

22. The electrostatic chuck according to claim 21, wherein the diameter of the porous ceramic plug at the second end of the porous ceramic plug is smaller than the diameter of the porous ceramic plug at the first end of the porous ceramic plug.

23. The electrostatic chuck according to claim 21, wherein the ceramic coating extends between the porous ceramic plug and the base plate.

24. The electrostatic chuck according to claim 21, wherein the plurality of ceramic plug coatings extend to the first surface.

25. It is an electrostatic chuck, A base plate having a conductive body, Multiple gas passages within the base plate, A plurality of plug holes in the base plate, wherein the ends of each plug hole are chamfered on the surface of the base plate, The anodized layer on the surface of the base plate, wherein the anodized layer does not extend over the chamfered portion of the plug hole, A plurality of porous ceramic plugs, wherein each of the plurality of porous ceramic plugs is located within the plug holes of the plurality of plug holes, A plurality of ceramic plug coatings on the side surface of the plurality of porous ceramic plugs, wherein each of the plurality of porous ceramic plugs has the ceramic plug coating of the plurality of ceramic plug coatings, An electrostatic chuck comprising a ceramic coating on at least a first surface of the base plate, wherein the anodic oxide layer is located between the ceramic coating and the surface of the base plate.

26. It is an electrostatic chuck, A base plate having a conductive body, Multiple gas passages within the base plate, A plurality of plug holes in the base plate, wherein the ends of each plug hole are chamfered on the surface of the base plate, A plurality of porous ceramic plugs, wherein each of the plurality of porous ceramic plugs is located within the plug holes of the plurality of plug holes, A plurality of ceramic plug coatings on the side surface of the plurality of porous ceramic plugs, wherein each of the plurality of porous ceramic plugs has the ceramic plug coating of the plurality of ceramic plug coatings, and the plurality of porous ceramic plugs and the plurality of ceramic plug coatings do not come into contact with the base plate, An electrostatic chuck comprising a ceramic coating on at least a first surface of the base plate.

27. The electrostatic chuck according to claim 26, further comprising an adhesive for connecting the plurality of ceramic plug coatings to at least one of the base plate and the ceramic coatings.

28. The electrostatic chuck according to claim 26, wherein each combination of porous ceramic plug and ceramic plug coating forms a countersink shape.

29. It is an electrostatic chuck, A base plate having a conductive body, Multiple gas passages within the base plate, A plurality of plug holes in the base plate, wherein the surface of the base plate has chamfered edges on each of the plug holes and is laser-processed, A plurality of porous ceramic plugs, wherein each of the plurality of porous ceramic plugs is located within the plug holes of the plurality of plug holes, A plurality of ceramic plug coatings on the side surface of the plurality of porous ceramic plugs, wherein each of the plurality of porous ceramic plugs has the ceramic plug coating of the plurality of ceramic plug coatings, An electrostatic chuck comprising a ceramic coating on at least a first surface of the base plate.

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