Apparatus, system and method for providing a secure chuck

Abstract

An apparatus, system, and method for providing a fixture chuck for positioning a wafer in a hold-related process. The fixture chuck can include a substrate having a plurality of machined concentric ridges on an upper surface thereof forming a series of concentric circular regions, a silicon carbide coating on the upper surface of the substrate, and a plurality of silicon carbide inlays bondable to the silicon carbide coating in the concentric circular regions.

Description

[0001] Cross Reference to Related Applications

[0002] This application claims priority to U.S. Provisional Application No. 62 / 976165, filed February 13, 2020, entitled “Apparatus, System, and Method for Providing a Fixed Chuck,” the entire contents of which are incorporated herein by reference, as fully set forth herein. Background Technology Technical Field

[0004] The present invention relates to the transfer and handling of articles such as semiconductor wafers, and more particularly to apparatus, systems and methods for providing a fixed chuck.

[0005] BACKGROUND

[0006] The use of robotics has been recognized as a manufacturing expedient, particularly in applications where manual operation is inefficient and / or unsatisfactory. One such application is in the semiconductor industry, where robots and automated stations are used to handle and hold wafers throughout various process steps. These steps can include, for example, chemical mechanical planarization (CMP), etching, deposition, passivation, and a variety of other processes, where a sealed and / or “clean” environment must be maintained to limit the possibility of contamination and ensure that various specific process conditions are met.

[0007] Current practices in the semiconductor industry for automating the handling of these wafers typically involve using flippers / aligners operatively connected to robots, for example, to load semiconductor wafers from loading stacks into various processing ports that correspond to the aforementioned exemplary process steps. Robots are used to actuate the flippers / aligners to retrieve wafers from specific ports or stacks, for example, before and / or after processing in the relevant processing chamber, and / or to associate wafers with stations, such as station chucks for placing the wafers.

[0008] Therefore, wafers can be moved between stations by robots associated with flippers / aligners for additional processing. When a given wafer processing is complete, the robot can move the processed wafer from its station and return the processed semiconductor wafer to the loading port. Typically, stacks of semiconductor wafers are processed in this way during each process run using the movement of flippers / aligners to stations.

[0009] Typically, the aforementioned substrate / wafer processes require the use of highly precise measurement units. For example, wafer inspection machines can employ laser measurement units that require a very high degree of positional stability of the wafer with respect to the measurement unit, and thus a very high degree of positional stability of the wafer with respect to the chuck on which the wafer is located. Accordingly, these aspects of wafer processing systems typically require vacuum chucks, which are typically made of silicon carbide.

[0010] However, due to the extremely high hardness of silicon carbide, chucks formed from such material are difficult to manufacture and costly, and their manufacture can be exceptionally time consuming. Accordingly, alternatives to manufacturing a finished silicon carbide vacuum chuck have been developed. For example, a blank plate can be coated with loose silicon carbide spheres, e.g., on the order of 100 pm in size. The spheres can be sintered or otherwise adhered to the blank to form a porous surface. However, such a process is fraught with risk, as there is likely to be gaps in the coating, or an uneven or chunky surface. Furthermore, the spheres can become loose during formation of the chuck, or worse, during wafer processing.

[0011] More particularly, during these semiconductor wafer processes, the chucks are used, for example, to hold silicon wafers. During such processing, it is desirable that these chucks remain chemically inert and contamination free, such that the wafers are not damaged during processing. Furthermore, as noted above, these chucks should hold the wafers with very small variations in position, and thus must be imbued with maximum positional rigidity, while also minimizing contact with the wafer surface so as not to damage features formed on the wafer.

[0012] Accordingly, there is a need for a low cost, high rigidity, easy to manufacture silicon carbide chuck for semiconductor processes. SUMMARY

[0013] Certain embodiments are directed to an apparatus, system, and method for providing a fixed chuck to position a wafer held in an associated process. The fixed chuck can include a substrate having a plurality of machined concentric ridges on an upper surface thereof, the concentric ridges forming a series of concentric circular regions; a silicon carbide coating on the upper surface of the substrate; and a plurality of silicon carbide inlays bondable to the silicon carbide coating in the concentric circular regions.

[0014] Accordingly, the present invention provides at least one apparatus, system, and method for a low cost, high rigidity, easy to manufacture silicon carbide chuck for semiconductor processes. BRIEF DESCRIPTION OF DRAWINGS

[0015] Exemplary components, systems and methods will hereinafter be described with reference to the drawings, which are given by way of non-limiting example only, in which:

[0016] FIG. 1is a schematic diagram of a wafer processing system;

[0017] FIG. 2 is a schematic diagram of aspects of a chuck;

[0018] FIG. 3 is a schematic diagram of aspects of a chuck; and

[0019] FIG. 4 is a schematic diagram of aspects of a chuck system. DETAILED DESCRIPTION

[0020] The drawings and description provided herein can have been simplified to illustrate aspects that are relevant to a clear understanding of the herein described devices, systems, and methods, while eliminating, for the purpose of clarity, other aspects that can be found in typical similar devices, systems, and methods. Those of ordinary skill in the art may, therefore, recognize that other elements and / or operations can be desirable and / or necessary to implement the devices, systems, and methods described herein. But because such elements and operations are known in the art, and because they do not facilitate a better understanding of the present application, a discussion of such elements and operations can not be provided herein. However, the present application is deemed to nevertheless include all such elements, variations, and modifications that can be known in the art to be desirable and / or necessary to implement the described aspects.

[0021] Embodiments are provided throughout the text so that the present application is fully and thoroughly understood and so that the scope of the disclosed embodiments is conveyed to those skilled in the art. Numerous specific details are set forth, such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present application. However, it will be apparent to those skilled in the art that the specific disclosed embodiments need not be limited to the particular disclosed details and that the embodiments can be practiced with different forms. Accordingly, the disclosed embodiments are not to be construed as limiting the scope of the present application. As noted above, in some embodiments, well-known processes, well-known device structures, and well-known techniques can not be described in detail.

[0022] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. For example, as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises" and "comprising" are to be construed as

[0023] When an element or layer is referred to as being "on", "connected to", or "coupled to" another element or layer, it can be directly on, connected or coupled to the other element or layer, or intervening elements or layers can be present. In contrast, when an element or layer is referred to as being "directly on", "directly connected to", or "directly coupled to" another element or layer, there are no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., "between" versus "directly between", "adjacent" versus "directly adjacent", etc.). In addition, as used herein the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0024] In addition, while the terms first, second, third, etc. can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, one element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present embodiments.

[0025] FIG. 1An automated processing system 100 is shown that is adapted to precisely handle semiconductor wafers, thin films, or similar substrates 102 of varying diameters, compositions, and physical properties. The processing system 100 is capable of rapidly, sequentially processing substrates 102 in an orderly fashion. The supplied substrates 102 can be manipulated or transferred between various fixed points 103 for processing, in part, by a robot (e.g., a robot arm 104) equipped with an edge clamp system 106 adapted to perform the aforementioned manipulations and transfers. The fixed points 103 can include one or more chucks, e.g., that can clamp the substrate 102 when placed thereon. Such clamping can be performed, for example, by using one or more vacuum devices 105.

[0026] Not only can the shape or diameter of the substrates 102 vary, but they are also typically manufactured according to standardized specifications that can require, in addition to dimensional tolerances including diameter, that the surface of the fixed points 103 used to receive the substrates 102 be substantially planar, such as having a flatness of 1.5 microns or less. By way of example, the substrates can be silicon wafers, e.g., 200 mm silicon wafers, e.g., that can have a standard diameter of 200 + / - 0.2 mm and a standard thickness of 675 + / - 25 microns. A typical wafer thickness after processing can be about 500 microns to about 700 microns. Thus, maintaining flatness on the substrates 102 during their interaction with the fixed points 103 and with the robot 104 and edge clamp 106 is critical to achieving acceptable substrate yield and waste levels in the processing system 100.

[0027] It has been determined that silicon carbide is a non-flaking compound and, thus, is very useful in a wafer processing environment, at least due to the cleanliness provided by the non-flaking nature of silicon carbide. In addition, silicon carbide is electrostatically dissipative and, thus, is also very useful in a wafer processing environment because undissipated static electricity can be harmful to wafers in processing.

[0028] In addition, silicon carbide sheet stock can be vacuum permeable and can be shaped in at least two dimensions. Silicon carbide can additionally be sputtered onto other substrates, such as graphite. These "hybrid" or "plated" silicon carbide parts are often used in the semiconductor industry.

[0029] The combination of custom hybrid silicon carbide parts and vacuum permeable silicon carbide plates provides a suitable foundation for the formation of wafer handling chucks, such as inspection platen plates. This is at least because the porous silicon carbide plates can provide a high mountain micro-surface that is ideal for minimizing surface contact with the wafer portions placed on the chuck, which is highly desirable in wafer handling to avoid damage or contamination to the processed wafer; as noted above, the rigidity imparted by silicon carbide maximizes wafer support during processing, which avoids "curling" damage to the processed wafer. For example, the pores provided in the silicon carbide castings can be 15-30 pm in size, thus providing a very low contact surface.

[0030] More particularly, embodiments can provide a hybrid silicon carbide wafer handling chuck on a structural graphite core or baseplate that can be machined using conventional equipment such as a CNC mill. The baseplate is easier, faster, and more economical to build than a blank silicon carbide plate. It is also noted that, as discussed further below, the hybrid silicon carbide chuck base can have a contoured vacuum pocket and ports on its backside.

[0031] More particularly, the graphite core can be coated with silicon carbide, for example, by sputtering. As a non-limiting example, the sputtering can be performed in an autoclave having a thickness of about 100 pm. Thus, embodiments can provide a hybrid silicon carbide chuck having properties equivalent to those of a blank silicon carbide plate.

[0032] As a non-limiting example, the vacuum zone pockets mentioned above can additionally receive a mating porous plate therein having a thickness of about 1.5-3.5 mm. As a non-limiting example, the mating porous plate can include pores in the range of 15-30 pm, and can be incorporated into the baseplate described above. These porous plates can further minimize wafer contact, which provides the process benefits discussed throughout this document.

[0033] Notably, the porous inserts and hybrid baseplate can be clamped independently to a flat fixture plate. Indeed, the baseplate can include access holes for this fixture purpose, for example, to allow a plurality of dowels to pass through the baseplate and clamp the porous inserts to a common datum or surface. As a non-limiting example, the baseplate can also be clamped to this datum or surface.

[0034] As noted above, the foregoing construction using silicon carbide castings and electrostatically dissipative porous silicon carbide inserts plates can provide an ideal wafer holding processing surface. That is, the wafer processing surface can provide maximum rigidity and minimum surface contact, and can be constructed in a shorter lead time, faster speed, cheaper cost, and easier manner than the prior art.

[0035] FIG. 2 A modular silicon carbide chuck 200 is shown in accordance with embodiments. The chuck 200 can include a base core 202, such as a graphite core, having a silicon carbide coating 204 thereon. As a non-limiting example, the thickness of the coating 204 can range from 50-250 μιη, and more particularly can be about 100 μιη. Further, as a non-limiting example, the silicon carbide coating 204 can be electrostatically dissipative, and can have a stiffness of 10Λ5-10Λ9 ohm-cm.

[0036] FIG. 2 Also shown in the center is a plurality of porous silicon carbide vacuum-embedded regions 208. Although three such regions 208 are shown in the embodiment of FIG. 2 the present invention, those skilled in the art will appreciate that other numbers of vacuum regions 208 can be employed without departing from the scope of the present invention.

[0037] FIG. 3 is a top view of a silicon carbide-coated chuck 200 having a plurality of separate vacuum-embedded regions 208. In the illustrated embodiment, as a non-limiting example, three regions 208 are provided, and these regions can correspond to 150 mm, 200 mm, and 300 mm regions. Each region can include a vacuum channel 220 corresponding to the size of a wafer that is accommodated in that region. That is, each region 208 can accommodate a different wafer size, although the inner regions can be used in conjunction with the outer ring regions for larger wafers in order to provide additional positional stiffness thereto.

[0038] FIG. 4 is shown throughout the present summary. In the FIG. 4 middle of the three-part modular system is a silicon carbide-coated chuck 200 having vacuum-embedded regions 208 therein, as discussed above with respect to FIG. 2 and FIG. 3 may be a series of porous inlays 302, such as can be constructed of silicon carbide. These porous inlays 302 are preferably made to be vacuum-permeable, and can minimize wafer surface contact. The pores provided in the porous inlays 302 can be, for example, on the order of 10-75 μιη, and more particularly, for example, on the order of 15-35 μιη.

[0039] provided in the lowermost portion of the illustration, which can be affixed to the underside of the silicon carbide-coated chuck 200. For example, the hub 306 can be secured with a pin 307 to provide optimal mating with the chuck 200, and can further provide vacuum and / or clamping through-holes 220, as shown. As a non-limiting example, the hub 306 can be formed of stainless steel or a similar clean and inert material.

[0040] exist FIG. 4 Also noticeable in the chuck system 300 is a series of vacuum channel seals 320. These vacuum channel seals 320 can provide optimal vacuum distribution to the silicon carbide-coated chuck 200 through or around the hub 306.

[0041] Therefore, the implementation provides the same silicon carbide chuck and low contact surface as known silicon carbide billet chucks, but with significantly lower overall cost and faster construction time compared to known silicon carbide billet chucks. Needless to say, this allows for a modifiable, transferable, and scalable structure of the disclosed implementation compared to known technologies.

[0042] Furthermore, embodiments may provide separate vacuum embedding regions, as described above, which enable processing using various wafer sizes with respect to the disclosed embodiments. These vacuum embedding regions may include or have reference silicon carbide inlays bonded thereto to provide a highly porous surface that provides a high ratio of vacuum contact to physical contact for the processing wafer associated with the chuck system disclosed herein.

[0043] The foregoing apparatus, systems, and methods may also include control over the various robotic and vacuum functionalities mentioned herein. As a non-limiting embodiment, such control may include manual control using one or more user interfaces, such as controllers, keyboards, mice, touchscreens, etc., to allow the user to input instructions to be executed by software code associated with the robot and the systems discussed herein. Alternatively, as is well known to those skilled in the art, system control may also be fully automated, for example, where manual user interaction occurs only for functions referenced by "setting up" and programming; that is, the user may initially program or upload computational code to execute a predetermined sequence of movements, vacuum suction, and operations discussed herein. In manual or automatic implementations or any combination thereof, the controller may be programmed, for example, to associate the known position of the substrate, the robot, the anchor point, and the relative positions therein.

[0044] It should also be understood that the systems and methods described herein can operate and / or be controlled by any computing environment. Therefore, it should not be assumed that the computing environment employed limits the implementation of the systems and methods described herein in computing environments with a wide variety of components and configurations. In other words, the concepts described herein can be implemented in a variety of computing environments using any of the various components and configurations.

[0045] Furthermore, the description of the invention is provided to enable any person skilled in the art to make or use the disclosed embodiments. Various modifications to the invention will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of the invention. Therefore, the content of this invention is not intended to be limited to the embodiments and designs described herein, but should be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A fixed chuck for positioning and holding a wafer in related processing, comprising: A substrate having a plurality of machined concentric ridges on its upper surface, the plurality of machined concentric ridges forming a series of concentric circular regions; A silicon carbide coating is provided on the upper surface of the substrate. as well as Multiple silicon carbide inlays are available, which can be bonded to the silicon carbide coating in the concentric circular regions, and the silicon carbide inlays are vacuum permeable.

2. The fixed chuck according to claim 1, wherein, The substrate is graphite.

3. The fixed chuck according to claim 1, wherein, The silicon carbide coating includes a sputtered coating.

4. The fixed chuck according to claim 1, wherein, The process includes wafer inspection.

5. The fixed chuck according to claim 1, wherein, The silicon carbide coating includes pores with a size of 15-30 μm.

6. The fixed chuck according to claim 1, wherein, The concentric ridges are machined using CNC milling.

7. The fixed chuck according to claim 1, wherein, The silicon carbide coating has a thickness in the range of 50-250 μm.

8. The fixed chuck according to claim 7, wherein, The silicon carbide coating has a thickness of 100 μm.

9. The fixed chuck according to claim 1, wherein the thickness of the silicon carbide insert is 1.5-3.5 mm.

10. The fixed chuck according to claim 1, wherein, The silicon carbide inlay includes pores ranging from 15 to 30 μm.

11. The fixed chuck of claim 1, further comprising a plurality of vacuum ports passing through the substrate and the silicon carbide coating.

12. The fixed chuck according to claim 11, wherein, The vacuum port substantially corresponds to the concentric ridge of the process.

13. The fixed chuck according to claim 1, wherein, The silicon carbide coating is electrostatically dissipative in the range of 10^5-10^9 ohm-cm.

14. The fixed chuck according to claim 1, wherein, The concentric ridges of the process correspond to areas of 150 mm, 200 mm, and 300 mm.

15. The fixed chuck according to claim 14, wherein, The region corresponds to the size of the wafer in the process.

16. The fixed chuck according to claim 1, further comprising a hub coupled to the underside of the substrate.

17. The fixed chuck according to claim 16, wherein, The hub is secured with pins to best fit the underside.

18. The fixed chuck according to claim 16, wherein, The hub is made of stainless steel.

19. The fixed chuck according to claim 16, further comprising a vacuum channel seal, the vacuum channel seal distributing vacuum through the hub.

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