Advanced method for fabricating electrostatic chuck (ESC) mesa patterns

Abstract

The embodiments disclosed herein include an electrostatic chuck (ESC). In one embodiment, the ESC comprises a substrate having a first surface, wherein the first surface has a first surface roughness. The ESC may further comprise a plurality of mesa extending upward from the first surface. In one embodiment, each of the plurality of mesa comprises a second surface, wherein the second surface has a second surface roughness. In one embodiment, both the first surface roughness and the second surface roughness have an average surface roughness (Ra) of about 0.3 μm or less.

Description

Technical Field

[0001] Cross - reference to related applications This application claims priority to U.S. Patent Application No. 18 / 131,534, filed on April 6, 2023, the entire content of which is incorporated herein by reference.

[0002] Embodiments relate to the field of semiconductor manufacturing, and more particularly, to a laser ablation process for manufacturing an electrostatic chuck (ESC) having a customizable mesa and gas groove pattern.

[0003] Description of related technology In semiconductor processing, chucks (such as electrostatic chucks (ESC)) are used to hold wafers and other substrates in various processing steps. An ESC device can induce an electrostatic clamping force, by which the wafer is held in contact with the ESC. The ESC device can include a Coulomb - type chuck or a Johnsen - Rahbek - type (JR) chuck. Generally, a dielectric surface (typically ceramic) is the substrate that interfaces with the wafer. With the increasing complexity of semiconductor processing, the complexity of the ESC is also increasing. The ceramic surface of the ESC is often patterned to form features (such as mesas or protrusions, grooves or channels for back - side gas flow).

[0004] Currently, the patterning process for ceramic substrates is carried out using mechanical removal processes. For example, masking, machining, grinding, and abrasive material blasting are some of the processing steps that must be performed for the manufacture of ESCs. These processes are time-consuming. In addition, thorough cleaning is required to remove residual particles (uncleaned residual particles can cause contamination). Furthermore, such processing steps can lead to an increase in surface roughness. There are also limitations to dimensional control in such processes. For example, the typical tolerance for machined features on an ESC is approximately 125 μm or more. The existing processing steps also limit the ease with which process designs can be modified. Due to the inherent complexity of manufacturing, changing the design (regardless of scale) may require an entirely new process flow. [Overview of the Initiative]

[0005] The embodiments disclosed herein include an electrostatic chuck (ESC). In one embodiment, the ESC comprises a substrate having a first surface, wherein the first surface has a first surface roughness. The ESC may further comprise a plurality of mesa extending upward from the first surface. In one embodiment, each of the plurality of mesa comprises a second surface, wherein the second surface has a second surface roughness. In one embodiment, both the first surface roughness and the second surface roughness have an average surface roughness Ra of about 0.3 μm or less.

[0006] The embodiments disclosed herein may further include electrostatic chucks comprising a substrate having a center and an edge. In one embodiment, a first mesa is located near the center of the substrate, wherein the first mesa has a first shape and a first height. In one embodiment, a second mesa is located near the edge of the substrate, wherein the second mesa has a second shape and a second height. In one embodiment, the first shape is different from the second shape and / or the first height is different from the second height.

[0007] The embodiments disclosed herein further include a method for forming an electrostatic chuck. In one embodiment, the method includes polishing a first surface of a substrate and forming a plurality of mesa on the first surface of the substrate using a laser ablation process. In one embodiment, the method may further include forming gas grooves between the mesa of the substrate. [Brief explanation of the drawing]

[0008] [Figure 1A] This is a plan view of an electrostatic chuck (ESC) with mesa extending upward from a ceramic substrate. [Figure 1B] This is a cross-sectional view of the ESC along the line B-B' in Figure 1A. [Figure 1C] This is a magnified view of the ESC, showing a patterned surface with high surface roughness resulting from the use of conventional manufacturing processes. [Figure 2] This is a process flow diagram of a process for manufacturing ESCs using a laser ablation process according to one embodiment. [Figure 3A] This is a cross-sectional view of a polished ESC substrate according to one embodiment. [Figure 3B] This is a cross-sectional view of an ESC during a laser ablation process for forming a mesa, according to one embodiment. [Figure 3C] This is a cross-sectional view of an ESC during a laser ablation process for forming a gas groove, according to one embodiment. [Figure 4A] This is a cross-sectional view of an ESC having a uniform mesa according to one embodiment. [Figure 4B] This is a cross-sectional view of an ESC according to one embodiment, which has a high mesa in the center of the ESC compared to the edges of the ESC. [Figure 4C] This is a cross-sectional view of an ESC according to one embodiment, which has a lower mesa in the center of the ESC compared to the edges of the ESC. [Figure 5] This is an enlarged cross-sectional view of an ESC (Electronic Surface Cavity) according to one embodiment, showing uniform surface roughness between the upper surface of the mesa and the concave surface of the substrate. [Figure 6A]This is an enlarged cross-sectional view of an ESC having a mesa including a dome-shaped top surface and vertical side walls, according to one embodiment. [Figure 6B] This is an enlarged cross-sectional view of an ESC having a dome-shaped mesa according to one embodiment. [Figure 6C] This is an enlarged cross-sectional view of an ESC having multiple mesas of different shapes according to one embodiment. [Figure 6D] This is an enlarged cross-sectional view of an ESC having mesas and gas grooves between mesas according to one embodiment. [Figure 6E] This is an enlarged cross-sectional view of an ESC having a mesa and gas groove with rounded corners, according to one embodiment. [Figure 7] This is a plan view of an ESC having a mesa and a gas channel according to one embodiment. [Figure 8] This is a plan view of an ESC having a mesa with non-uniform dimensions from the center to the edge, according to one embodiment. [Figure 9] A block diagram of an exemplary computer system that may be used in conjunction with a processing tool, according to one embodiment, is shown. [Modes for carrying out the invention]

[0009] The system described in this book includes a laser ablation process for manufacturing electrostatic chucks (ESCs) having customizable mesa and gas groove patterns. Numerous specific details are provided in the following description to provide a comprehensive understanding of the embodiments. Those skilled in the art will see that the embodiments are implementable even without these specific details. In other words, well-known embodiments are not described in detail to avoid unnecessarily obscuring the embodiments. Furthermore, it should be understood that the various embodiments shown in the accompanying drawings are illustrative and not necessarily drawn to scale.

[0010] To illustrate the embodiments disclosed herein, a typical electrostatic chuck (ESC) 100 is shown in Figure 1A. As shown, the ESC 100 may comprise a substrate 105 having a plurality of mesa 110. The mesa 110 may be circular projections extending upward from the substrate 105 (i.e., out of the plane in Figure 1A). The mesa 110 may be made of the same material as the substrate 105, as shown in uniform color. More specifically, the mesa may be an integral part of the ESC 100. For example, a physical material removal process may be used to concave the upper surface of the substrate 105 around the mesa 110.

[0011] As described above, the manufacturing process used to form the mesa 110 on the ESC 100 is a physical material removal process. For example, masking, machining, grinding, and abrasive material blasting are part of the processing steps performed to form the mesa 110. In such a process, it is not possible to precisely control the size or tolerance of the features. For example, tolerances can be approximately 125 μm or more. In addition, a thorough cleaning process is required to prepare the ESC for use in the processing environment (plasma chamber, rapid heat treatment chamber, or other processing chamber, etc.).

[0012] Referring now to Figure 1B, a cross-sectional view is shown along line B-B' of ESC100 in Figure 1A. As shown, the mesa 110 has a uniform shape and dimensions across the entire surface of the substrate 105. That is, the mesa 110 near the center of the substrate 105 may be substantially similar to the mesa 110 near the edges of the substrate 105.

[0013] The shape of mesa 110 is also limited to a structure that is easy to machine with the physical removal process as described above. For example, mesa 110 has a rectangular shape. That is, the upper surface 111 is substantially flat and parallel to the flat concave surface 106 of substrate 105. Further, the side wall surface 112 is substantially perpendicular. Such a shape can be harmful in some semiconductor processing environments. For example, the sharp corners of mesa 110 may become stress points or cause unwanted particle generation. Therefore, there may be cases where it is desirable to have a mesa shape 110 with a more rounded upper surface 111.

[0014] In addition, mesa 110 has a uniform width and height across substrate 105. A uniform mesa 110 may be desirable for processing a completely flat substrate. However, when layers are added to the substrate during manufacturing, the substrate may warp due to the mismatch in the coefficient of thermal expansion (CTE) between materials. When a uniform mesa 110 is used, on a warped substrate, the processing may not be successful or additional stress may occur. Therefore, in some embodiments, a non-uniform mesa 110 height and / or width may be required.

[0015] Referring now to FIG. 1C, an enlarged cross-sectional view of ESC 100 is shown. The enlarged portion includes a pair of mesas 110 and the concave surface 106 of substrate 105 between the mesas 110. As shown, the upper surface 111 of mesa 110 and the concave surface 106 have different roughness levels. This is due to the processing of ESC 100. For example, the upper surface 111 of mesa 110 can be polished to have a low surface roughness (shown as substantially smooth in FIG. 1C), while the surface roughness of the concave surface 106 can be high. The low surface roughness of the upper surface 111 can have an average roughness Ra of about 0.03 μm or less. The high roughness of the concave surface 106 can have an average roughness Ra of about 0.3 μm or more.

[0016] The difference in surface roughness between the upper surface 111 of the mesa 110 and the concave surface 106 of the substrate 105 can be the result of a physical material removal process. For example, the surface can be roughened by machining, grinding, and / or abrasive blasting. On the other hand, the upper surface 111 can be protected by a masking layer before material removal begins after a polishing process is used to polish the substrate 105. That is, in existing physical material removal processes, differences in the surface roughness of different layers can occur.

[0017] Therefore, the embodiments disclosed in this document include an advanced patterning process for forming a mesa on a substrate. In certain embodiments, the patterning process can include the use of a laser. The laser can ablate the substrate material instead of partially and physically removing the substrate. Generally, in a physical removal process, one or more solid materials (such as machining tools or abrasive grains) need to directly contact the substrate to partially remove the substrate. Instead of such a physical process, electromagnetic radiation (i.e., by a laser) is used to partially and directly remove the substrate. In certain embodiments, the laser is a picosecond laser or has an even higher pulse frequency.

[0018] Such embodiments offer several advantages compared to existing solutions. One of the advantages is that the profile of the mesa can be controlled. The mesa can have a rounded or otherwise non-flat surface rather than being limited to a flat upper surface. This can reduce stress points and minimize particle generation. A laser process may also be used to form a non-uniform mesa. For example, the mesa can be higher closer to the center of the substrate and lower closer to the edge of the substrate. Of course, the reverse configuration (i.e., lower closer to the center and higher closer to the edge) is also achievable. Using the laser process also enables easy control of the width of the mesa.

[0019] Furthermore, the modifiability provided by the laser embodiment allows for easy modification of the ESC design. Modifying the ESC structure may only require changing the laser's movement or intensity. Such modifications can be easily made by updating the laser's program.

[0020] In one embodiment, the speed of manufacturing ESCs can also be improved. Instead of a time-consuming physical removal process (which requires thorough cleaning to remove particles) to pattern the substrate, a laser ablation process is used. The laser can rapidly scan the entire surface of the substrate to pattern the desired structure. In addition, the laser ablation process does not form many (or virtually no) particles. This eliminates the time required for cleaning the substrate after mesa fabrication. Furthermore, the laser ablation process used to form the mesa can also be used to form gas grooves in the substrate (sequentially or simultaneously). This also reduces manufacturing time.

[0021] The embodiments disclosed herein further maintain a smooth surface on the patterned surface. For example, the top surface of the mesa may have a surface roughness approximately equal to the surface roughness of the concave surface of the substrate. The embodiments disclosed herein may include an average surface roughness Ra of about 0.3 μm or less, or about 0.03 μm or less.

[0022] Referring to Figure 2, a process flow diagram of process 270 for manufacturing an ESC according to one embodiment is shown. Processes 271-273 correspond to Figures 3A-3C, respectively.

[0023] In one embodiment, process 270 may begin with step 271, which includes polishing the upper surface 321 of the ceramic substrate 305. As shown in Figure 3A, the ESC 300 includes the substrate 305. The substrate 305 can be any suitable dielectric ceramic material. For example, the substrate 305 may include aluminum oxide (Al2O3) or any other dielectric ceramic material suitable for the purpose of semiconductor manufacturing. The substrate 305 is illustrated as a solid block of material. However, it should be recognized that embodiments may include the substrate 305 (including electrodes) or other components used to enable the ESC 300. In one embodiment, the substrate 305 may have a thickness of about 100 μm or more. For example, in some embodiments, the substrate 305 may have a thickness of about 5,000 μm or more.

[0024] In one embodiment, the upper surface 321 of the substrate 305 may be polished. For example, in some embodiments, a chemical mechanical polishing (CMP) process may be used. The polished upper surface 321 may have an average surface roughness Ra of about 5 μm or less, about 1 μm or less, about 0.3 μm or less, or about 0.03 μm or less.

[0025] In one embodiment, process 270 may be followed by process 272, which includes forming a mesa on the upper surface of a ceramic substrate using a laser ablation process. It should be noted that, although referred to as "laser ablation," material "vaporization" can also be a result of the laser process. As shown in Figure 3B, the laser 340 scans the entire substrate 305. In the illustrated embodiment, the mesa 310 is formed by a single pass of the laser 340. However, it should be noted that in some embodiments, two or more passes of the laser 340 may be used to form the mesa 310.

[0026] The ceramic material is ablated by the laser 340 to form a concave surface 306. The concave surface 306 may be provided around the mesa 310. In one embodiment, the mesa 310 may include side walls 312 and a top surface 311. In one embodiment, the side walls 312 may be substantially vertical (i.e., perpendicular to the concave surface 306). However, it should be noted that in some embodiments, the side walls 312 may be inclined depending on the laser parameters. In one embodiment, the top surface 311 may be coplanar with the top surface 321. That is, the top surface 311 may not undergo laser ablation. However, in other embodiments, the top surface 311 may be a result of part of the laser ablation and may be located below the top surface 321.

[0027] In one embodiment, laser 340 may be a high-pulse-frequency laser. In certain embodiments, laser 340 has a pulse length in the picosecond range or shorter (e.g., in the femtosecond range). For example, laser 340 can also be called a pico-laser. In certain embodiments, a 290 fs laser 340 may be used. Lasers of any suitable wavelength may be used. For example, in some embodiments, a 1030 nm laser may be used. The laser power may be set to a maximum of about 500 W. In certain embodiments, the laser power may be about 100 W. As used herein, "approximately" may refer to a range of values ​​within 10% of the stated value. For example, about 100 W may refer to a range between 90 W and 110 W. It should be noted that even if a specific range is presented herein, any configuration of laser 340 capable of precise photoablation according to the embodiments disclosed herein may be used.

[0028] The laser ablation process described in this document provides a significant improvement in the tolerances of the mesa 310. For example, embodiments may include dimensional tolerances of less than 10 μm or less than 1 μm. This is a significant improvement compared to devices manufactured by physical material removal, which have tolerances of 125 μm or more. For example, in some embodiments, the height of the mesa 310 may be approximately 20 μm or less, approximately 15 μm or less, or approximately 10 μm or less. Furthermore, although all mesa 310s in Figure 3B are shown to have the same height, it should be noted that embodiments may include mesa 310s with different heights, as will be detailed below.

[0029] In one embodiment, process 270 may be followed by process 273, which includes forming gas grooves on the upper surface of a ceramic substrate using a laser ablation process. As shown in Figure 3C, the laser 340 may be scanned across the entire substrate to form gas grooves 315 between mesa 310. In the illustrated embodiment, the mesa 310 are completed first, and then the gas grooves 315 are formed within the concave surfaces 306. However, in other embodiments, the gas grooves 315 may be formed simultaneously with the formation of the mesa 310. In one embodiment, the same laser 340 may be used to form both the mesa 310 and the gas grooves 315. In other embodiments, different lasers 340 or the same laser with different laser settings may be used to form the mesa 310 and the gas grooves 315.

[0030] In one embodiment, the gas groove 315 may have a depth of approximately 10 μm or less. However, in some embodiments, a deeper gas groove 315 may be used. In the illustrated embodiment, the gas groove 315 has a substantially flat bottom and vertical side walls. However, other configurations may be used, as will be detailed below.

[0031] Referring here to Figures 4A-4C, a series of ESC400s according to various embodiments are shown. Each of the ESC400s shown in Figures 4A-4C may be formed using a process (such as process 270, which is detailed above). Furthermore, although gas grooves are not shown in the figures, it should be noted that gas grooves may be manufactured within the substrate 405, similar to Figure 3C.

[0032] Referring here to Figure 4A, a cross-sectional view of an ESC400 according to one embodiment is shown. In one embodiment, the ESC400 includes a substrate 405. The substrate 405 may be a dielectric ceramic substrate. For example, the substrate 405 may contain aluminum and oxygen (e.g., aluminum oxide (Al2O3)). In one embodiment, a plurality of mesa 410 may extend upward from a concave surface 406 of the substrate 405. The mesa 410 may have substantially similar shapes and dimensions throughout the substrate 405. For example, all mesa 410 may have a height H. The height H may be about 20 μm or less, about 15 μm or less, or about 5 μm or less.

[0033] In one embodiment, the mesa 410 may have a substantially flat top surface 411. That is, the top surface 411 may be substantially parallel to the concave surface 406. In some embodiments, the top surface 411 may be connected to the concave surface 406 by substantially vertical side walls. The shape of the mesa 410 can generally be considered rectangular (when viewed in cross-section). The mesa 410 is circular when viewed from above (to give the mesa 410 a cylindrical shape). However, the laser ablation process is easily modifiable, and the mesa 410 may have any three-dimensional shape. As used in this document, the “shape” of the mesa 410 may be a representation of either the three-dimensional shape of the mesa 410 or the cross-sectional shape of the mesa 410.

[0034] Referring here to Figure 4B, a cross-sectional view of the ESC400 according to a further embodiment is shown. As shown, the ESC400 includes a substrate 405 having a concave surface 406. In one embodiment, multiple mesa may have non-uniform dimensions across the substrate 405. For example, a mesa 410 near the center of the substrate 405 may have a first height H1, and a second mesa 410 near the edge of the substrate 405 may have a second height H2. In one embodiment, the first height H1 may be greater than the second height H2. In addition, mesa between the center and the edge may decrease in height from H1 to H2. Such an embodiment may be beneficial if the wafer being processed on the ESC400 is warped.

[0035] Referring here to Figure 4C, a cross-sectional view of the ESC400 according to yet another embodiment is shown. In one embodiment, the ESC400 in Figure 4C is the same as the ESC400 in Figure 4B, except that the heights are reversed. That is, the first height H1 near the center of the substrate 405 may be smaller than the second height H2 near the edge of the substrate 405. Similarly, the height of the mesa 410 between the center and the edge may increase as its position moves outward. Such an embodiment may be suitable for processing wafers having a warp in the opposite direction to the warp suitable for the embodiment shown in Figure 4B.

[0036] Referring here to Figure 5, an enlarged cross-sectional view of the ESC500 according to one embodiment is shown. The ESC500 may include a substrate 505. The mesa 510 may extend upward from the concave surface 506. The upper surface 511 of the mesa 510 may be connected to the concave surface 506 by a side wall 512. As described above, laser ablation results in a substantially smooth surface. Even if the upper surface 511 is a polished surface, the concave surface 506 may maintain a similar surface roughness. That is, the surface roughness of the upper surface 511 may be substantially equal to the surface roughness of the concave surface 506. As used in this text, "substantially equal" may refer to two values ​​within a 10% range from each other. In certain embodiments, the average surface roughness Ra of the upper surface 511 and the concave surface 506 may be about 5 μm or less, about 1 μm or less, about 0.3 μm or less, or about 0.03 μm or less. It should be noted that this uniformity of surface roughness differs from existing ESCs that use a physical patterning process (which leaves the concave surfaces significantly rougher than the mesa top surface).

[0037] In addition, although the average surface roughness Ra of the upper surface 511 is shown to be substantially equal in surface roughness, it may differ from the average surface roughness Ra of the concave surface 506. In one embodiment, both surfaces 511 and 506 may be smoother than the roughness provided by a typical mechanical removal process (e.g., surface roughness of about 1 μm or less, about 0.3 μm or less, or about 0.03 μm or less), but may still differ from each other. For example, surface 511 may have a surface roughness of about 0.03 μm or less, and surface 506 may have a surface roughness of about 0.3 μm or less. While an example has been presented in which the upper surface 511 is smoother than the concave surface 506, the embodiments are not limited to such a configuration. In other embodiments, the concave surface 506 may be smoother than the upper surface 511.

[0038] Referring here to Figures 6A-6E, a series of cross-sectional views are shown depicting ESC600s with different mesa topography according to various embodiments. Various mesa shapes are possible by using a laser ablation process. For example, various laser settings may be used to modify the mesa shape and / or make it possible to change the mesa shape within a single ESC600.

[0039] Referring here to Figure 6A, a cross-sectional view of an ESC600 according to one embodiment is shown. The ESC600 may include a substrate 605 having a concave surface 606. The mesa 610 may extend upward from the concave surface 606. As shown in Figure 6A, the mesa 610 may have a non-planar upper surface 611. The upper surface 611 can be described as rounded or dome-shaped. In one embodiment, the upper surface 611 may be connected to the concave surface 606 by side walls 612 (such as vertical walls 612). More specifically, the dome-shaped upper surface 611 may rise from the concave surface 606.

[0040] Referring now to Figure 6B, a cross-sectional view of the ESC600 according to another embodiment is shown. In the embodiment shown in Figure 6B, the upper surface 611 is directly connected to the concave surface 606. In other words, the mesa 610 has no side walls at all. Instead, the dome-shaped upper surface 611 is directly above the concave surface 606.

[0041] Referring here to Figure 6C, a cross-sectional view of the ESC600 according to another embodiment is shown. In the embodiment shown in Figure 6C, the mesa 610 has a non-uniform shape. For example, the first mesa 610A has a dome-shaped or curved upper surface 611A, and the second mesa 610B has a flat upper surface 611B. Although two examples of different mesa 610 shapes are shown in Figure 6C, it should be noted that any kind of different mesa 610 shape can be formed using the laser ablation process as detailed in this document.

[0042] Referring here to Figure 6D, a cross-sectional view of the ESC600 according to another embodiment is shown. In the embodiment shown in Figure 6D, the ESC600 further comprises a gas groove 615 formed between the mesa 610. The gas groove 615 may include a flat bottom surface 616. The bottom surface 616 may be parallel to the concave surface 606. In addition, the gas groove 615 may have substantially vertical side walls 617.

[0043] Referring here to Figure 6E, a cross-sectional view of the ESC600 according to yet another embodiment is shown. As shown in Figure 6E, the corners of the structure are rounded. For example, corner 613 (where the top surface 611 and the side wall surface 612 meet) and corner 618 (where the concave surface 606 and the bottom surface 616 meet) may be rounded. In addition, the bottom surface 616 of the gas groove 615 may also be rounded. It may be desirable to provide rounded corners to alleviate high stress concentration and / or reduce particle formation. Such curved surfaces cannot be easily machined using standard physical machining processes.

[0044] Referring here to Figure 7, a plan view of the ESC700 according to one embodiment is shown. In one embodiment, the ESC700 may include a substrate 705 and a plurality of mesa 710 extending upward from the substrate 705. While a certain configuration of the mesa 710 is illustrated as an example, it should be noted that the ESC700 may include any number of mesa 710, including hundreds or more. In one embodiment, the mesa 710 may have a uniform shape and dimensions. In other embodiments, non-uniform shapes or dimensions may be used, as in any of the embodiments detailed in this document.

[0045] In one embodiment, the ESC700 may also include gas grooves 715. The gas grooves 715 may be used to disperse gas across the entire back surface of the wafer or substrate during processing. In one embodiment, the gas grooves 715 may be manufactured together with the mesa 710 (e.g., simultaneously or sequentially) using a laser ablation process such as the process detailed in this document. It should be noted that the location and number of gas grooves 715 are illustrative, and any configuration of gas grooves 715 may be used.

[0046] Referring here to Figure 8, a plan view of the ESC800 according to a further embodiment is shown. In detail, the ESC800 has mesa 810 of non-uniform dimensions. For example, mesa 810C near the center of the substrate 805 has a first diameter, and mesa 810E near the edge of the substrate 805 has a different second diameter. In the embodiment shown in Figure 8, the first diameter is larger than the second diameter. However, in other embodiments, the first diameter may be smaller than the second diameter. In addition, the spacing between the mesa 810 may be non-uniform in some embodiments. Furthermore, the mesa 810 may have non-uniform heights, as in other embodiments detailed in this document.

[0047] Radial non-uniformity may also be applied to other parameters of the ESC. For example, surface roughness can be adjusted across the entire surface of the ESC. In such embodiments, zones at different locations radially on the ESC may have different surface roughness. In one embodiment, the mesa of the ESC (in a first zone towards the center of the ESC) may have a first surface roughness. In addition, the back gas seal band (in a second zone towards the edge of the ESC) may have a second surface roughness lower than the first surface roughness. Such embodiments may result in improved sealing of back gases during processing, along with improved dechuck performance. The rougher the mesa surface, the less susceptible it may be to residual charge. Non-uniformity of surface roughness can be achieved by modifying the laser parameters used to form various features.

[0048] Referring here to Figure 9, a block diagram of an exemplary computer system 900 of a processing tool according to one embodiment is shown. In one embodiment, the computer system 900 is connected to the processing tool and controls the processing in the processing tool. The computer system 900 may be connected to other machines on a local area network (LAN), intranet, extranet, or internet (for example, it may be networked with other machines). The computer system 900 may operate as a server or client machine in a client-server network environment, or as a peer machine in a peer-to-peer (or distributed) network environment. The computer system 900 may be a personal computer (PC), tablet PC, set-top box (STB), personal digital assistant (PDA), mobile phone, web appliance, server, network router, switch or bridge, or any machine capable of executing a set of instructions (sequential or different) (the instruction set specifies the actions performed by that machine). Furthermore, although only a single machine is illustrated as computer system 900, the term "machine" should also be interpreted to include any collection of machines (e.g., computers) that individually or in conjunction execute instruction sets (or sets) to perform any one or more of the methods described herein.

[0049] The computer system 900 may include a computer program product or software 922 having a non-transient machine-readable medium on which instructions are stored, and the instructions may be used to program the computer system 900 (or other electronic device) to perform a process according to an embodiment. The machine-readable medium includes any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computer). For example, the machine-readable (e.g., computer-readable) medium includes machine-readable storage media (e.g., read-only memory (ROM), random-access memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, etc.) and machine-readable transmission media (e.g., propagating signals in electrical, optical, acoustic, or other forms, such as infrared signals or digital signals, etc.).

[0050] In one embodiment, the computer system 900 includes a system processor 902, main memory 904 (for example, read-only memory (ROM), flash memory, dynamic random access memory (DRAM) such as synchronous DRAM (SDRAM) or rhombus DRAM (RDRAM), etc.), static memory 906 (for example, flash memory or static random access memory (SRAM), etc.), and secondary memory 918 (such as a data storage device), all of which communicate with each other via a bus 930.

[0051] The system processor 902 represents one or more general-purpose processing devices (e.g., a microsystem processor or a central processing unit). More specifically, the system processor may be a composite instruction set arithmetic (CISC) microsystem processor, a reduced instruction set arithmetic (RISC) microsystem processor, a very long instruction word (VLIW) microsystem processor, a system processor implementing another instruction set, or a system processor implementing a combination of instruction sets. The system processor 902 may also be one or more special-purpose processing devices, such as an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a digital signal system processor (DSP), or a network system processor. The system processor 902 is configured to execute processing logic 926 for performing the steps described in this document.

[0052] The computer system 900 may further include a system network interface device 908 for communicating with other devices or machines. The computer system 900 may further include a video display unit 910 (such as a liquid crystal display (LCD), light-emitting diode display (LED), or cathode ray tube (CRT)), an alphanumeric input device 912 (such as a keyboard), a cursor control device 914 (such as a mouse), and a signal generation device 916 (such as a speaker).

[0053] The secondary memory 918 may include a machine-accessible storage medium 932 (or, more specifically, a computer-readable storage medium) that stores one or more instruction sets (e.g., software 922) that embody any one or more of the methods or functions described herein. Furthermore, the software 922 may reside in the main memory 904 and / or the system processor 902, in whole or in part, while being executed by the computer system 900. The main memory 904 and the system processor 902 also constitute a machine-readable storage medium. The software 922 may further be transmitted and received over the network 960 via a system network interface device 908. In one embodiment, the network interface device 908 may operate using RF coupling, optical coupling, acoustic coupling, or inductive coupling.

[0054] In one exemplary embodiment, the machine-accessible storage medium 932 is shown as a single medium, but the term “machine-readable storage medium” should be interpreted to include a single or multiple mediums that store one or more instruction sets (e.g., a centralized or distributed database, and / or associated caches and servers). The term “machine-readable storage medium” should also be interpreted to include any medium that is capable of storing or encoding instruction sets executed by a machine, and that causes the machine to execute one or more of these methods. Therefore, the term “machine-readable storage medium” should be interpreted to include, but not be limited to, solid-state memory, optical media, and magnetic media.

[0055] In the aforementioned specification, specific and illustrative embodiments have been described. It will be obvious that various modifications can be made to these embodiments without departing from the scope of the claims described below. Therefore, this specification and the drawings should be considered illustrative, not limiting.

Claims

1. It is an electrostatic chuck (ESC), A substrate having a first surface having a first surface roughness, A plurality of mesas extending upward from the first surface, each including a second surface, the second surface having a second surface roughness, The first and second surface roughnesses both have an average surface roughness (Ra) of approximately 0.3 μm or less. Electrostatic chuck (ESC).

2. The ESC according to claim 1, wherein the plurality of mesas have non-uniform heights.

3. The ESC according to claim 2, wherein the first mesa toward the center of the substrate has a first height, and the second mesa toward the edge of the substrate has a second height different from the first height.

4. The ESC according to claim 3, wherein the first height is greater than the second height.

5. The ESC according to claim 3, wherein the first height is lower than the second height.

6. The ESC according to claim 1, wherein the second surface is dome-shaped.

7. The ESC according to claim 6, wherein the second surface is connected to the first surface by substantially vertical side walls.

8. The ESC according to claim 1, further comprising gas grooves on the first surface of the substrate.

9. The ESC according to claim 1, wherein the height of each of the plurality of mesas is at most about 15 μm.

10. The ESC according to claim 1, wherein the first surface roughness is substantially equal to the second surface roughness.

11. The ESC according to claim 1, wherein the first surface roughness is different from the second surface roughness.

12. The ESC according to claim 1, further comprising a sealing band on the peripheral edge of the substrate, wherein the sealing band has a third surface roughness, and the third surface roughness is smoother than the second surface roughness.

13. It is an electrostatic chuck (ESC), A substrate having a central part and edges, A first mesa in the vicinity of the central part of the substrate, having a first shape and a first height, A second mesa in the vicinity of the edge of the substrate, the second mesa having a second shape and a second height, The first shape is different from the second shape, and / or the first height is different from the second height, Electrostatic chuck (ESC).

14. The ESC according to claim 13, wherein the first height is greater than the second height.

15. The ESC according to claim 13, wherein the first shape has a rectangular cross-section and the second shape has a dome-shaped cross-section.

16. The ESC according to claim 13, wherein the dome-shaped surface of the second shape is connected to the substrate by substantially vertical side walls.

17. The ESC according to claim 13, wherein the substrate has a first surface roughness, the upper surface of the first mesa and the upper surface of the second mesa have a second surface roughness, and the first surface roughness is substantially equal to the second surface roughness.

18. The ESC according to claim 17, wherein the first surface roughness and the second surface roughness have an average surface roughness (Ra) of about 1 μm or less.

19. A method for forming an electrostatic chuck (ESC), Polishing the first surface of the substrate, Using a laser ablation process, a plurality of mesa are formed on the first surface of the substrate, Forming gas grooves between the mesas of the substrate, Methods that include...

20. The method according to claim 19, wherein the laser ablation process is carried out using a laser with a pulse frequency of picoseconds or more.

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