Electrostatic wafer chuck and method of manufacturing the same
By using a combination of an alumina layer, an adhesive layer, and an anti-wear layer in the protrusion structure of the electrostatic wafer chuck, the problems of wear and breakage of the protrusion structure are solved, achieving the effect of low wear and long life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD
- Filing Date
- 2017-03-10
- Publication Date
- 2026-06-09
AI Technical Summary
The protruding structure of existing electrostatic wafer mounting bases is prone to wear and breakage, resulting in uneven heating of the wafer, extrusion defects, and a short service life.
The structure employs a combination of an alumina layer, an adhesive layer, and an anti-wear layer. By leveraging the adhesion between the alumina layer and the bearing seat, and the bonding between the adhesive layer and the anti-wear layer, the wear resistance of the protruding structure is enhanced, and wear is reduced.
It effectively reduces the wear of electrostatic wafer holders, extends their service life, and reduces the damage rate of wafers during the manufacturing process.
Smart Images
Figure CN114551322B_ABST
Abstract
Description
[0001] This application is a divisional application of the patent application filed on March 10, 2017, with application number 201710141535.4 and invention title "Electrostatic Wafer Adsorption Base and Manufacturing Method Thereof". Technical Field
[0002] This disclosure relates to an electrostatic wafer chuck and its manufacturing method, and more particularly to an electrostatic wafer chuck comprising a protrusion structure having a specific material composition and thickness ratio, and its manufacturing method. The aforementioned electrostatic wafer chuck has advantages such as low wear and long service life. Background Technology
[0003] In semiconductor manufacturing, electrostatic chucks, which utilize electrostatic adsorption to hold wafers, have the advantage of being less likely to damage the wafers compared to mechanical clamping systems. Therefore, electrostatic chucks are often installed in the process cavity to hold the wafers, facilitating processes such as chemical vapor deposition, physical vapor deposition, or dry etching.
[0004] Generally, electrostatic wafer chucks have multiple protrusions on their surface. The spaces between these protrusions allow for gas flow, facilitating uniform heat transfer from the heating element to each protrusion. However, before being held by the electrostatic wafer chuck, the wafer has a slightly convex central surface, making the protrusions on the periphery of the chuck prone to wear and even breakage. The reduced thickness and / or altered contact area of the worn or broken protrusions lead to uneven heating of the wafer, resulting in extrusion defects and the formation of unintended protrusions on the wafer surface. Due to these problems, electrostatic wafer chucks commonly used in semiconductor manufacturing processes have a relatively short lifespan.
[0005] In view of the above problems, there is an urgent need to propose an electrostatic wafer chuck and its manufacturing method, which can effectively improve the shortcomings of wear and breakage of the protrusion structure of the electrostatic wafer chuck, so as to extend the service life of the electrostatic wafer chuck. Summary of the Invention
[0006] Therefore, one aspect of this disclosure is to provide an electrostatic wafer chuck that can reduce wear during use through a specific protrusion structure.
[0007] Another aspect disclosed herein is a method for manufacturing an electrostatic wafer saddle, which can produce the aforementioned electrostatic wafer saddle.
[0008] Based on the above-disclosed specifications, an electrostatic wafer holder is proposed. In one embodiment, the electrostatic wafer holder may include a support base and a plurality of protruding structures. The support base has a first surface, wherein the support base is used to support a wafer on the first surface. The plurality of protruding structures are distributed on the first surface, and each protruding structure includes an alumina layer, an adhesive layer, and an anti-wear layer, wherein the alumina layer is embedded in the first surface, the adhesive layer is disposed on the alumina layer, and the anti-wear layer is disposed on the adhesive layer for contacting the wafer. An interface between the alumina layer and the adhesive layer is lower than the first surface, wherein the anti-wear layer has a cross-section parallel to the first surface, the adhesive layer has a cross-section parallel to the first surface, the cross-section of the anti-wear layer and the cross-section of the adhesive layer have the same shape, and the cross-section of the anti-wear layer and the cross-section of the adhesive layer coincide when viewed from above, and the support base has a second surface opposite to the first surface. The electrostatic wafer holder further includes at least a pair of electrodes, a heating element, and a cooling layer. The at least one pair of electrodes is embedded in the support, the heating element is embedded in the support and located between the at least one pair of electrodes and the second surface, and the cooling layer is disposed on the second surface.
[0009] Based on the above-described embodiments disclosed herein, a method for manufacturing an electrostatic wafer mounting base is proposed. In one embodiment, the method first provides a carrier having a first surface for supporting a wafer on the first surface, wherein a plurality of alumina layers are embedded on the first surface of the carrier, and the plurality of alumina layers are exposed from the first surface. Next, an adhesive layer is deposited on each alumina layer using a mask. Then, an anti-wear layer is deposited on the adhesive layer on each alumina layer using the aforementioned mask, wherein the anti-wear layer protrudes from the first surface. The method then provides a cooling layer, at least one pair of electrodes, and a heating element, the cooling layer being bonded to a second surface of the carrier opposite the first surface, the at least one pair of electrodes being embedded in the carrier, and the heating element being embedded in the carrier and located between the at least one pair of electrodes and the second surface.
[0010] Based on the above-described embodiments disclosed herein, an electrostatic wafer chuck is proposed. In one embodiment, the electrostatic wafer chuck may include a carrier and a plurality of protruding structures. The carrier has a first surface, wherein the carrier is used to support a wafer on the first surface. The plurality of protruding structures are distributed on the first surface, and each protruding structure includes an alumina layer, an adhesive layer, and an anti-wear layer, wherein the alumina layer is embedded in the first surface, the adhesive layer is disposed on the alumina layer, and the anti-wear layer is disposed on the adhesive layer for contacting the wafer. The carrier has a second surface opposite the first surface. The electrostatic wafer chuck further includes at least a pair of electrodes, a heating element, and a cooling layer. The at least a pair of electrodes are embedded in the carrier, the heating element is embedded in the carrier and located between the at least a pair of electrodes and the second surface, and the cooling layer is disposed on the second surface. Attached Figure Description
[0011] This disclosure will be more easily understood by reading the following detailed description and accompanying drawings. It is emphasized that, in accordance with industry standard practice, the features are not drawn to scale and are for illustrative purposes only. In fact, the dimensions of the features can be arbitrarily enlarged or reduced for clarity of discussion.
[0012] Figure 1A This is a schematic cross-sectional view of an electrostatic wafer mounting base according to an embodiment of the present disclosure;
[0013] Figure 1B and Figure 1C This is a top view illustrating an electrostatic wafer mounting base as described in some embodiments disclosed herein;
[0014] Figures 1D to 1F This is a partially enlarged cross-sectional schematic diagram illustrating the carrier and protrusion structure of the electrostatic wafer adsorption base as described in some embodiments disclosed herein;
[0015] Figures 2A to 2C This is a cross-sectional schematic diagram illustrating various intermediate stages of a method for manufacturing an electrostatic wafer chuck according to some embodiments of the present disclosure.
[0016] Figure 3 This is a schematic flowchart illustrating a method for manufacturing an electrostatic wafer chuck according to some embodiments of the present disclosure. Detailed Implementation
[0017] The following disclosure provides numerous different embodiments or examples to implement various features of this disclosure. Specific examples of components and arrangements described below are intended to simplify this disclosure. These are merely examples and are not intended to be limiting. For instance, in the description, a first feature is formed above or on a second feature, which may include embodiments where the first and second features are formed in direct contact, or embodiments where additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. Furthermore, this disclosure may repeat element symbols and / or letters in various examples. Such repetition is for simplification and clarity and is not, in itself, intended to specify relationships between the various embodiments and / or configurations discussed.
[0018] Furthermore, spatially relative terms such as “directly below,” “below,” “lower,” “above,” “above,” and similar terms are used herein to simply describe the relationship of an element or feature in the accompanying drawings to another element or feature. These spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to those shown in the accompanying drawings. For example, if the device in the accompanying drawings is flipped, an element described as below or directly below another element or feature would be positioned above or directly above that other element or feature. Therefore, the illustrative term “below” can include above or below. The device may also change its orientation (rotated 90° or in other orientations), and the spatially relative descriptions used herein can be explained accordingly.
[0019] This disclosure provides an electrostatic wafer chuck, which has multiple protruding structures distributed on a first surface of the carrier. Each protruding structure is formed by stacking an alumina layer, an adhesive layer, and an anti-wear layer. The adhesion between the protruding structure and the carrier is strengthened through the adhesion between the alumina layer and the carrier, and between the adhesive layer and the alumina layer. Furthermore, the wear of the protruding structure is reduced through the high-hardness anti-wear layer with a low coefficient of friction with the wafer surface. Therefore, the electrostatic wafer chuck disclosed herein has advantages such as low wear, long service life, and reduced wafer damage rate during the manufacturing process.
[0020] The wafers referred to herein may be, for example, bulk silicon wafers, silicon on insulator (SOI) with doped or undoped layers, or other similar materials coated on insulating layers such as gallium arsenide, sapphire, or glass.
[0021] Please refer to Figure 1A This is a schematic cross-sectional view illustrating an electrostatic wafer mounting base according to an embodiment of the present disclosure. Figure 1AAs shown, the electrostatic wafer holder 100 includes a carrier 110 and a plurality of protrusions 120. The carrier 110 has a first surface 111 for holding a wafer (not shown) on the first surface 111. The plurality of protrusions 120 are distributed on the first surface 111, wherein each protrusion 120 includes an alumina layer adhesive layer and an anti-wear layer (e.g., ...). Figures 1D to 1F The alumina layer 126, adhesive layer 124, and anti-wear layer 122 are shown. In some embodiments, the plurality of protrusions 120 are uniformly distributed on the first surface 111. Please refer to... Figure 1B and Figure 1C The figures are top views illustrating electrostatic wafer mounting bases according to some embodiments of the present disclosure. In one example, the plurality of protrusion structures 120 may be arranged, for example, in a spiral manner (e.g., Figure 1B As shown), concentric circles (such as...) Figure 1C (as shown) or other similar arrangements, evenly distributed on the first surface 111 of the support 110.
[0022] In some embodiments, the carrier 110 has a second surface 113 opposite to the first surface 111, and the electrostatic wafer adsorption carrier 100 may further include at least one pair of electrodes 112, a heating element 114, a cooling layer 130, and a gas channel 140. The at least one pair of electrodes 112 are embedded in the carrier 110 and adjacent to the first surface 111, the heating element 114 is embedded in the carrier 110 and located between the at least one pair of electrodes 112 and the second surface 113, the cooling layer 130 is disposed on the second surface 113, and the gas channel 140 penetrates the cooling layer 130 and the carrier 110.
[0023] In some embodiments, the electrostatic wafer chuck has a pair of electrodes (such as...) Figure 1A The electrode 112 is provided, wherein one of the electrodes 112 may be electrically connected to a power supply (not shown), and the other of the electrodes 112 may be grounded. In some embodiments, the electrode 112 may be annular, strip-shaped, wedge-shaped, crescent-shaped, or other shapes. In some embodiments, the metallic material of the electrode 112 may be, for example, molybdenum, tungsten, a combination thereof, a molybdenum-based alloy, or a tungsten-based alloy, wherein the molybdenum-based alloy or tungsten-based alloy may, for example, contain nickel or cobalt. It should be noted that although only one pair of electrodes is shown herein, two or more pairs of electrodes may be used depending on the application requirements, the design of the electrostatic wafer chuck, etc., and the accompanying drawings are not intended to limit the scope of this disclosure.
[0024] In some embodiments, the heating element 114 is coupled to a heating device (not shown) to adjust the temperature of the electrostatic wafer accelerator 100 using the heating device. In some embodiments, the material of the heating element 114 may be, for example, pyrolytic graphite, a metallic material, or other materials with good thermal conductivity.
[0025] In some embodiments, the cooling layer 130 may be engaged with the carrier 110, for example, by screwing. In some embodiments, the cooling layer 130 includes cooling lines 132 to provide flow of cooling water.
[0026] In some embodiments, the gas passage 140 may be in communication with a gas supply device 150 to provide gas for uniformly conducting the heat generated by the heating element 114 to each protruding structure 120. In some examples, the gas may be, for example, but not limited to, argon, helium, nitrogen, other inert gases, or any combination thereof.
[0027] Please refer to the following: Figure 1D This is a partially enlarged cross-sectional schematic diagram illustrating the carrier 110 and protrusion structure 120 of the electrostatic wafer adsorption holder described in some embodiments of this disclosure. Figure 1D As shown, the protrusion structure 120 is distributed on the first surface 111, and the protrusion structure 120 includes an alumina layer 126, an adhesive layer 124, and an anti-wear layer 122. The alumina layer 126 is embedded in the first surface 111, and the surface 126A of the alumina layer 126 is aligned with the first surface 111. The adhesive layer 124 is disposed on the alumina layer 126, and the anti-wear layer 122 is disposed on the adhesive layer 124 on the alumina layer 126. The anti-wear layer 122 is used to contact the wafer (not shown). In other words, the adhesive layer 124 and the anti-wear layer 122 protrude from the first surface 111 of the carrier 110.
[0028] Please refer to Figure 1E This is a partially enlarged cross-sectional schematic diagram illustrating the carrier 110 and protrusion structure 120 of the electrostatic wafer chuck as described in other embodiments of this disclosure. Figure 1E As shown, the protrusion structure 120 is distributed on the first surface 111, and the protrusion structure 120 includes an alumina layer 126, an adhesive layer 124, and an anti-wear layer 122. The alumina layer 126 is embedded in the first surface 111, and surface 126A of the alumina layer 126 is located in the first surface 111 of the carrier 110. The adhesive layer 124 is disposed on the alumina layer 126, and a portion of the adhesive layer 124 protrudes from the first surface 111. The anti-wear layer 122 is disposed on the adhesive layer 124 on the alumina layer 126, and the anti-wear layer 122 is used to contact the wafer (not shown). In other words, a portion of the adhesive layer 124 and the anti-wear layer 122 protrude from the first surface 111 of the carrier 110.
[0029] Please refer to Figure 1F This is a partially enlarged cross-sectional schematic diagram illustrating the carrier 110 and protrusion structure 120 of the electrostatic wafer mounting base according to some other embodiments disclosed herein. Figure 1F As shown, the protrusion structure 120 is distributed on the first surface 111, and the protrusion structure 120 includes an alumina layer 126, an adhesive layer 124, and an anti-wear layer 122. The alumina layer 126 is embedded in the first surface 111, and surface 126A of the alumina layer 126 protrudes from the first surface 111 of the carrier 110. The adhesive layer 124 is disposed on the alumina layer 126, and the anti-wear layer 122 is disposed on the adhesive layer 124 on the alumina layer 126. The anti-wear layer 122 is used to contact the wafer (not shown). In other words, a portion of the alumina layer 126, the adhesive layer 124, and the anti-wear layer 122 protrude from the first surface 111 of the carrier 110.
[0030] In one embodiment, the carrier 110 is composed of aluminum nitride (AlN), the adhesive layer 124 is a titanium (Ti) layer, and the anti-wear layer 122 is a titanium nitride (TiN) layer. Specifically, the anti-wear layer 122 (or titanium nitride layer) disclosed herein has relatively high hardness and a low coefficient of friction with the wafer surface (e.g., approximately 0.354), thus effectively reducing the wear of the protrusion structure in electrostatic wafer chucks used in semiconductor manufacturing processes. On the other hand, the adhesive layer 124 (or titanium nitride layer) disclosed herein has good adhesion to both aluminum oxide and titanium nitride, thus effectively strengthening the bond between the protrusion structure 120 and the carrier 110. Therefore, arbitrarily changing any of the above materials can result in insufficient hardness of the protrusion structure, increased friction at the wafer contact surface, higher wear of the electrostatic wafer chuck, or poor bond between the protrusion structure and the carrier.
[0031] In some embodiments, the wear-resistant layer 122 has a thickness T1, the adhesive layer 124 has a thickness T2, and the thickness ratio of the wear-resistant layer 122 to the adhesive layer 124 (i.e., thickness T1 / thickness T2) is 6 to 34. If the thickness ratio is less than 6, the thickness of the high-hardness wear-resistant layer 122 is insufficient, resulting in a short service life of the electrostatic wafer mounting base 100. If the thickness ratio is greater than 34 or the adhesive layer 124 is not used, the protrusion structure 120 is prone to detaching from the support base 110. Furthermore, the thinner the adhesive layer 124, the more easily the wear-resistant layer 122 is affected by the surface roughness of the alumina layer 126, thus increasing the wear of the wear-resistant layer 122.
[0032] In some embodiments, the top surface 120A of the protruding structure 120 may have a distance D of 3.25 μm to 4.25 μm between it and the first surface 111 (e.g., ...). Figures 1D to 1F (As shown). In other embodiments, the protruding structure 120 may have a width W of 2.2 μm to 2.4 μm. If the distance D between the top surface 120A of the protruding structure 120 and the first surface 111 is less than 3.25 μm, the gas generated by the gas supply device 150 is prone to overflow and cannot flow between each protruding structure 120, thus failing to uniformly conduct the heat of the heating element 114 to each protruding structure 120. On the other hand, if the distance D is greater than 4.25 μm, there is a disadvantage of uneven heating of the protruding structure 120. In addition, if the width W of the protruding structure 120 is less than 2.2 μm, the contact area with the wafer is too small, resulting in insufficient electrostatic adsorption. However, if the width W of the protruding structure 120 is greater than 2.4 μm, the distance between each protruding structure 120 is too dense, making it difficult for the heat-conducting gas to flow smoothly.
[0033] In some embodiments, the wear-resistant layer 122 and the adhesive layer 124 have exactly the same cross-sectional shape (e.g., Figure 1B and Figure 1C As shown in the top view of the protrusion structure 120, the cross-sectional shape refers to the plane of the cross-section parallel to the first surface 111. The term "identical" as used herein means that any cross-section of the anti-wear layer 122 and any cross-section of the adhesive layer 124 can completely coincide. In some embodiments, the cross-sectional shape may include, but is not limited to, a circle, a square, a rectangle, or other geometric shapes. If the cross-sectional shapes of the anti-wear layer 122 and the adhesive layer 124 are different (e.g., the cross-sectional area gradually decreases as the protrusion structure 120 moves away from the first surface 111), the contact area between the wafer (not shown) and the protrusion structure 120 will continuously change during wafer fabrication, which is detrimental to controlling the wafer fabrication process conditions.
[0034] Please refer to the following. Figures 2A to 3 ,in Figures 2A to 2C This is a cross-sectional schematic diagram illustrating various intermediate stages of a method for manufacturing an electrostatic wafer chuck according to some embodiments of this disclosure, and Figure 3 This is a schematic flowchart illustrating a method 300 for manufacturing an electrostatic wafer chuck according to some embodiments of the present disclosure. It should be noted that, for the sake of simplicity, the figures in this disclosure... Figure 2B and Figure 2C Only drawing Figure 2A The circles indicate the various intermediate stages in the manufacturing process. First, as... Figure 2A as well as Figure 3As shown, in operation 310, a carrier 210 having a first surface 211 is provided for carrying a wafer (not shown) on the first surface 211, wherein a plurality of alumina layers 226 are embedded on the first surface 211 of the carrier 210, and each alumina layer 226 is exposed from the first surface 211.
[0035] In some embodiments, the support 210 has a second surface 213 opposite to the first surface 211, at least one pair of electrodes 212 are embedded in the support 210 and adjacent to the first surface 211, and a heating element 214 is embedded in the support 210 and located between the at least one pair of electrodes 212 and the second surface 213. A cooling layer 230 is further provided on the second surface 213 of the support 210, and a gas channel 240 penetrates the cooling layer 230 and the support 210. In one embodiment, the cooling layer 230 is screwed onto the second surface 213. In some embodiments, the material of the support 210 may be aluminum nitride.
[0036] The aforementioned at least one pair of electrodes 212, heating element 214, cooling layer 230 and gas channel 240 are the same or similar in type, arrangement and function as the aforementioned at least one pair of electrodes 112, heating element 114, cooling layer 130 and gas channel 140, so they will not be described again here.
[0037] Next, as Figure 2B as well as Figure 3 As shown in operation 320, an adhesive layer 224 is deposited on the alumina layer 226 using a mask 250.
[0038] Then, as Figure 2C as well as Figure 3 As shown in operation 330, the anti-wear layer 222 is deposited again on the adhesive layer 224 on the alumina layer 226 using the mask 250 to form the protrusion structure 220.
[0039] It should be noted that the surface of the alumina layer 226 in the electrostatic wafer chuck prepared by the method 300 disclosed herein is aligned with the first surface 211 (similar to...). Figure 1D The structures shown are for illustrative purposes only. Those skilled in the art will understand that the above embodiments are intended to illustrate implementation methods of this disclosure and are not intended to limit the scope of this disclosure. Figure 1E , Figure 1F Other embodiments with modifications to the above-described structures can be produced by a manufacturing method similar to method 300.
[0040] In some embodiments, the adhesive layer 224 is a titanium layer and the anti-wear layer 222 is a titanium nitride layer. Specifically, the anti-wear layer 222 (or titanium nitride layer) disclosed herein has relatively high hardness and a low coefficient of friction with the wafer surface (e.g., approximately 0.354), thus effectively reducing the wear of the protrusion structure 220 used in semiconductor manufacturing processes. On the other hand, the adhesive layer 224 (or titanium layer) disclosed herein exhibits good adhesion to both alumina and titanium nitride, thus effectively strengthening the bond between the protrusion structure 220 and the carrier 210. Therefore, arbitrarily changing either of the above materials can result in insufficient hardness of the protrusion structure, increased friction at the wafer contact surface, higher wear of the electrostatic wafer chuck, or poor bond between the protrusion structure and the carrier.
[0041] In some embodiments, operations 320 and 330 described above can be performed using physical vapor deposition (PVD). In the example where the adhesive layer 224 is a titanium layer and the anti-wear layer 222 is a titanium nitride layer, operation 320 involves first introducing vaporized titanium gas until a titanium layer (or adhesive layer 224) of a predetermined thickness is formed. Then, in operation 330, vaporized titanium gas is continuously introduced, and additional nitrogen gas is introduced to form a titanium nitride layer (or anti-wear layer 222) of a predetermined thickness. Operations 320 and 330 described above can be performed, for example, at 200°C.
[0042] In some embodiments, the wear-resistant layer 222 has a thickness T3, the adhesive layer 224 has a thickness T4, and the thickness ratio of the wear-resistant layer 222 to the adhesive layer 224 (i.e., thickness T3 / thickness T4) is between 6 and 34. If the thickness ratio is less than 6, the high-hardness wear-resistant layer 222 is insufficient, resulting in a short service life of the electrostatic wafer chuck. If the thickness ratio is greater than 34 or the adhesive layer 224 is not formed, the protrusion structure 220 is prone to detaching from the support 210. Furthermore, the thinner the adhesive layer 224, the more easily the wear-resistant layer 222 is affected by the surface roughness of the alumina layer 226, thus increasing the wear of the wear-resistant layer 222.
[0043] In some embodiments, the top surface 220A of the protrusion structure 220 may have a distance D' of 3.25 μm to 4.25 μm between it and the first surface 211. In other embodiments, the protrusion structure 220 may have a width W2 of 2.2 μm to 2.4 μm. If the distance D' of the protrusion structure 220 is less than 3.25 μm or greater than 4.25 μm, the protrusion structure 220 cannot be heated uniformly. Furthermore, if the width W2 of the protrusion structure 220 is less than 2.2 μm, the contact area with the wafer is too small, resulting in insufficient electrostatic adsorption. However, if the width W2 of the protrusion structure 220 is greater than 2.4 μm, the distance between each protrusion structure 220 is too dense, preventing the heat-conducting gas from flowing smoothly.
[0044] In some embodiments, the wear-resistant layer 222 and the adhesive layer 224 have exactly the same cross-sectional shape (e.g., Figure 1B and Figure 1C As shown in the top view of the protrusion structure 120, the cross-sectional shape refers to the plane of the cross-section parallel to the first surface 211. "Completely identical" as used herein means that any cross-section of the anti-wear layer 222 completely coincides with any cross-section of the adhesive layer 224. In some embodiments, the cross-sectional shape may include, but is not limited to, a circle, a square, a rectangle, or other geometric shapes. If the cross-sectional shapes of the anti-wear layer 222 and the adhesive layer 224 are different (e.g., the cross-sectional area gradually decreases as the protrusion structure 220 moves away from the first surface 211), the contact area between the wafer (not shown) and the protrusion structure 220 will continuously change during wafer fabrication, which is detrimental to controlling the wafer fabrication process conditions.
[0045] In some embodiments, the electrostatic wafer chuck disclosed herein (e.g., electrostatic wafer chuck 100) can be applied to processes with operating temperatures of 300°C to 500°C. In some embodiments, the electrostatic wafer chuck disclosed herein can be applied to high throughput AlCu (HTP AlCu) processes, hot-deposited AlCu processes, or other similar semiconductor processes.
[0046] When the wafer is a bulk silicon wafer, in one example, the distance D' between the top surface 220A of the protrusion structure 220 and the first surface 211 is 3.5 μm and the width is 2.3 μm. The thickness of the anti-wear layer 222 is 3 μm and the thickness of the adhesive layer 224 is 0.5 μm, resulting in a thickness ratio of 6 between the anti-wear layer 222 and the adhesive layer 224. After subjecting the electrostatic wafer holder to an abrasion test at 350°C, the abrasion amount of the electrostatic wafer holder is 0.193 μm. The abrasion test described herein involves repeatedly rubbing the protrusion structure of the electrostatic wafer holder against the wafer several times.
[0047] In another example, the distance D' between the top surface 220A of the protrusion structure 220 and the first surface 211 is 3.5 μm and the width is 2.3 μm. The thickness of the anti-wear layer 222 is 3.4 μm and the thickness of the adhesive layer 224 is 0.1 μm, so the thickness ratio of the anti-wear layer 222 to the adhesive layer 224 is 34. After the above electrostatic wafer chuck was subjected to an abrasion test at 350°C, the abrasion amount of the electrostatic wafer chuck was 0.798 μm.
[0048] In another example, the distance D' between the top surface 220A of the protrusion structure 220 and the first surface 211 is 3.5 μm and the width is 2.3 μm. The thickness of the anti-wear layer 222 is 3.2 μm and the thickness of the adhesive layer 224 is 0.3 μm, so the thickness ratio of the anti-wear layer 222 to the adhesive layer 224 is 11. After the above electrostatic wafer chuck was subjected to an abrasion test at 350°C, the abrasion amount of the electrostatic wafer chuck was 0.372 μm.
[0049] In yet another example, the electrostatic wafer chuck disclosed herein has a lifespan of 0.5 to 1.5 years.
[0050] However, if a wear test is conducted using a titanium carbide (TiC) layer as the wear-resistant layer without an adhesive layer, the wear amount reaches as high as 1.161 μm due to the coefficient of friction between titanium carbide and the wafer surface being approximately 0.564. In the long term, the lifespan of the aforementioned electrostatic wafer holder with a titanium carbide wear-resistant layer is less than six months.
[0051] By applying the electrostatic wafer chuck and its manufacturing method disclosed herein, an adhesive layer can be deposited on the alumina layer of the carrier, followed by the deposition of an anti-wear layer on the adhesive layer to form a protruding structure. In semiconductor manufacturing processes, the protruding structure exhibits low wear due to wafer adsorption, resulting in a long service life and reduced wafer failure rate.
[0052] According to one embodiment, this disclosure provides an electrostatic wafer mounting base, which may include a carrier and a plurality of protruding structures. The carrier has a first surface, wherein the carrier is used to support a wafer on the first surface. The plurality of protruding structures are distributed on the aforementioned first surface, and each protruding structure includes an alumina layer, an adhesive layer, and an anti-wear layer, wherein the alumina layer is embedded in the first surface, the adhesive layer is disposed on the alumina layer, and the anti-wear layer is disposed on the adhesive layer for contacting the wafer.
[0053] According to one embodiment of this disclosure, the thickness ratio of the wear-resistant layer to the adhesive layer is 6 to 34.
[0054] According to one embodiment of the present disclosure, the alumina layer protrudes from the first surface.
[0055] According to one embodiment of the present disclosure, the bearing seat is composed of aluminum nitride, the adhesive layer is a titanium layer, and the wear-resistant layer is a titanium nitride layer.
[0056] According to one embodiment of this disclosure, the carrier has a second surface opposite the first surface, and the electrostatic wafer mounting carrier further includes at least one pair of electrodes, a heating element, a cooling layer, and a gas channel. At least one pair of electrodes is embedded in the carrier and adjacent to the first surface. The heating element is embedded in the carrier and located between the at least one pair of electrodes and the second surface. The cooling layer is disposed on the second surface. The gas channel extends through the cooling layer and the carrier.
[0057] According to another embodiment, this disclosure provides a method for manufacturing an electrostatic wafer mounting base. The method first provides a carrier having a first surface for supporting a wafer on the first surface, wherein a plurality of alumina layers are embedded on the first surface of the carrier, and the plurality of alumina layers are exposed from the first surface. Next, an adhesive layer is deposited on each alumina layer using a mask. Then, an anti-wear layer is deposited on the adhesive layer on each alumina layer using the aforementioned mask, wherein the anti-wear layer protrudes from the first surface.
[0058] According to one embodiment of this disclosure, the thickness ratio of the wear-resistant layer to the adhesive layer is 6 to 34.
[0059] According to one embodiment of this disclosure, the alumina layer protrudes from the first surface.
[0060] According to one embodiment of this disclosure, the bearing seat is composed of aluminum nitride, the wear-resistant layer is a titanium nitride layer, and the adhesive layer is a metallic titanium layer.
[0061] According to one embodiment of the present disclosure, the steps of depositing the adhesive layer and the anti-wear layer are performed using physical vapor deposition.
[0062] The foregoing description has outlined the features of several embodiments, thus enabling those skilled in the art to better understand the nature of this disclosure. Those skilled in the art should understand that they can readily use this disclosure as a basis to design or modify other processes and structures to achieve the same purpose and / or advantages as the embodiments described herein. Those skilled in the art should also understand that such equivalent architectures do not depart from the spirit and scope of this disclosure, and that various modifications, substitutions, and refinements can be made without departing from the spirit and scope of this disclosure.
Claims
1. An electrostatic wafer adsorption base, characterized in that, Include: A support having a first surface for supporting a wafer on the first surface; and Multiple protruding structures are distributed on the first surface, wherein each of the protruding structures comprises: an alumina layer embedded in the first surface; and an adhesive layer disposed on the alumina layer; An anti-wear layer is disposed on the adhesive layer for contacting the wafer, wherein an interface between the alumina layer and the adhesive layer is lower than the first surface, wherein the anti-wear layer has a cross-section parallel to the first surface, the adhesive layer has a cross-section parallel to the first surface, the cross-section of the anti-wear layer and the cross-section of the adhesive layer have the same shape, the top surface of each protrusion structure is 3.25 μm to 4.25 μm away from the first surface, and the cross-section of the anti-wear layer and the cross-section of the adhesive layer coincide when viewed from above, the carrier has a second surface opposite to the first surface, and the electrostatic wafer adsorption carrier further includes: At least one pair of electrodes is embedded in the support; A heating element is embedded in the support and located between the at least one pair of electrodes and the second surface; and A cooling layer is disposed on the second surface.
2. The electrostatic wafer adsorption holder according to claim 1, characterized in that, The thickness ratio of the wear-resistant layer to the adhesive layer is 6 to 34.
3. The electrostatic wafer adsorption holder according to claim 1, characterized in that, The bearing is composed of aluminum nitride, the adhesive layer is a titanium layer, and the wear-resistant layer is a titanium nitride layer.
4. The electrostatic wafer adsorption holder according to claim 1, characterized in that, Also includes: A gas passage runs through the cooling layer and the support.
5. The electrostatic wafer adsorption holder according to claim 1, characterized in that, The cooling layer also includes: A cooling pipeline is provided to allow the flow of cooling water.
6. The electrostatic wafer adsorption holder according to claim 1, characterized in that, Each of these protrusions has a width of 2.2 μm to 2.4 μm.
7. The electrostatic wafer adsorption holder according to claim 1, characterized in that, Part of the adhesive layer protrudes from the first surface.
8. A method for manufacturing an electrostatic wafer adsorption base, characterized in that, Include: A carrier is provided, wherein the carrier has a first surface for supporting a wafer on the first surface, wherein a plurality of alumina layers are embedded in the first surface of the carrier and the plurality of alumina layers are exposed from the first surface; An adhesive layer is deposited on each of the alumina layers using a mask; Using the mask, an anti-wear layer is deposited on the adhesive layer on each of the alumina layers, wherein the anti-wear layer protrudes from the first surface, the anti-wear layer has a cross-section parallel to the first surface, the adhesive layer has a cross-section parallel to the first surface, the cross-section of the anti-wear layer and the cross-section of the adhesive layer have the same shape, and the cross-section of the anti-wear layer and the cross-section of the adhesive layer coincide when viewed from above, and the top surface of the anti-wear layer is 3.25 μm to 4.25 μm away from the first surface; A cooling layer is provided, which is bonded to a second surface of the support opposite to the first surface; At least one pair of electrodes is provided, embedded in the support; and A heating element is provided, embedded in the support and located between the at least one pair of electrodes and the second surface.
9. The method for manufacturing an electrostatic wafer adsorption base according to claim 8, characterized in that, The ratio of the thickness of the wear-resistant layer to the thickness of the adhesive layer is 6 to 34.
10. The method for manufacturing an electrostatic wafer adsorption base according to claim 8, characterized in that, The alumina layer protrudes from the first surface.
11. The method for manufacturing an electrostatic wafer adsorption base according to claim 8, characterized in that, The bearing seat is composed of aluminum nitride, the wear-resistant layer is a titanium nitride layer, and the adhesive layer is a metallic titanium layer.
12. The method for manufacturing an electrostatic wafer adsorption base according to claim 8, characterized in that, The steps of depositing the adhesive layer and the anti-wear layer are performed using physical vapor deposition.
13. The method for manufacturing an electrostatic wafer adsorption base according to claim 8, characterized in that, The wear-resistant layer has a width of 2.2 μm to 2.4 μm.
14. The method for manufacturing an electrostatic wafer adsorption base according to claim 8, characterized in that, The adhesive layer protrudes from the first surface.
15. An electrostatic wafer adsorption base, characterized in that, Include: A support having a first surface for supporting a wafer on the first surface; and Multiple protruding structures are distributed on the first surface, wherein each of the protruding structures comprises: an alumina layer embedded in the first surface; and an adhesive layer disposed on the alumina layer; An anti-wear layer is disposed on the adhesive layer for contacting the wafer. The anti-wear layer has a cross-section parallel to the first surface, and the adhesive layer has a cross-section parallel to the first surface. The cross-sections of the anti-wear layer and the adhesive layer have the same shape and coincide when viewed from above. The top surface of each protrusion structure is 3.25 μm to 4.25 μm away from the first surface. The carrier has a second surface opposite the first surface. The electrostatic wafer holder further includes: At least one pair of electrodes is embedded in the support; A heating element is embedded in the support and located between the at least one pair of electrodes and the second surface; and A cooling layer is disposed on the second surface.
16. The electrostatic wafer adsorption holder according to claim 15, characterized in that, Also includes: A gas passage runs through the cooling layer and the support.
17. The electrostatic wafer adsorption holder according to claim 15, characterized in that, The cooling layer also includes: A cooling pipeline is provided to allow the flow of cooling water.
18. The electrostatic wafer adsorption holder according to claim 15, characterized in that, The surface of the alumina layer protrudes from the first surface.
19. The electrostatic wafer adsorption holder according to claim 15, characterized in that, The ratio of the thickness of the wear-resistant layer to the thickness of the adhesive layer is 6 to 34.
20. The electrostatic wafer adsorption holder according to claim 15, characterized in that, The bearing is composed of aluminum nitride, the adhesive layer is a titanium layer, and the wear-resistant layer is a titanium nitride layer.