METHODS AND APPARATUS TO MINIMIZE THE EFFECT OF TAPE TENSION IN ELECTRONIC DEVICE POLISHING
Methods and apparatus are provided for reducing tension on a polishing roller. In some aspects, a polishing head may be provided that is adapted to contact a substrate. The polishing head includes: a polishing unit having a polisher and at least one pair of tension distributors adapted to reduce tension on the polisher; and one or more pairs feed guides. Numerous other aspects are provided.
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The present application claims priority to U.S. Provisional Patent Application Ser. No. 61/108,102, filed Oct. 24, 2008, and entitled “METHODS AND APPARATUS TO MINIMIZE THE EFFECT OF TAPE TENSION IN ELECTRONIC DEVICE POLISHING” (Attorney Docket No. 12834/L), which is hereby incorporated herein by reference in its entirety for all purposes.
FIELD OF THE INVENTIONThe present invention relates to electronic device manufacturing, and more specifically to methods and apparatus for minimizing the effect of tape tension in electronic device polishing.
BACKGROUND OF THE INVENTIONSubstrates are used in electronic device manufacturing. During processing, a film may be deposited on the surface of a substrate. However, it may be undesirable to have a film on the edge of the substrate, as it may negatively affect the electronic devices formed on the substrate. Accordingly, methods and apparatus for efficiently and effectively removing a film from the edge of the substrate are desirable.
SUMMARY OF THE INVENTIONIn some aspects of the invention, an apparatus is provided that includes a polishing head, adapted to contact a substrate. The polishing head includes: (1) a polishing unit having a polishing roller and at least one pair of tension rollers adapted to reduce tension on the polishing roller; and (2) one or more pairs of stationary feed rollers.
In other aspects of the invention, a system is provided that includes a substrate support adapted to rotate a substrate; and a polishing head, adapted to contact a substrate. The polishing head includes (1) a polishing unit having a polishing roller and at least one pair of tension rollers adapted to reduce tension on the polishing roller, and (2) one or more pairs of stationary feed rollers. The system also includes a controller adapted to operate the polishing head.
In yet other aspects of the invention, a method is provided that includes (1) rotating a substrate; (2) selecting a balanced position for a polishing head; (3) contacting the substrate with a polishing film, whereby the polishing film is routed through the polishing head; (4) applying a force to the substrate via the polishing film; and (5) pivoting the polishing head about the substrate.
Other features and aspects of the present invention will become more fully apparent from the following detailed description, the appended claims, and the accompanying drawings.
Substrates used in semiconductor processing often have films and/or surface defects, which typically should be removed prior to subsequent processing steps. In some cases, these films and defects may occur on the edge of a substrate, including notches formed thereon. In conventional systems, the films and/or defects may be removed via a polishing apparatus that may include an abrasive polishing tape and/or abrasive pad adapted to contact and polish the edge and/or notch of the substrate.
The polishing tape typically is routed from a supply spool, over at least one feed guide, to a take-up spool. The rotation of the take-up spool may cause the polishing tape to advance from the supply spool. As the substrate rotates, a polisher may press the advancing polishing tape against the substrate. The polisher may exert a force, often a downward force, on the polishing tape as the polisher presses the polishing tape against the substrate, and the polishing tape, which is tensioned between the supply and take-up spools, may exert an opposing force or “tape tension” on the polisher. Therefore, the tape tension should be taken into account when determining the amount of force used to press the polisher against the substrate (via the polishing tape). However, the tape tension may vary based on, for example, the position of the polisher, the amount of polishing tape on either of the take-up or supply spools, etc. Other parameters may cause the tape tension to vary.
In some embodiments of the present invention, the tape tension may be reduced with an inventive polishing head design. The inventive polishing head design may include a polishing unit having the polisher and two additional guides (hereinafter referred to as “tension rollers”), which may be oriented to allow the polishing tape to lay substantially flat between feed guides and the polisher. Because the polishing tape lays substantially flat, the tape tension may be distributed differently, compared to other exemplary apparatuses, as described below, and therefore may apply less force on the polishing unit.
Additionally, in some embodiments of the present invention, the tension rollers may be coupled to the polishing head such that the polishing tape may be routed through the polishing head without removing the feed guides.
In some embodiments, one or more of the heads 110 may be adapted to be oscillated or moved (e.g., pivoted or angularly translated about a tangential axis of the substrate 102 and/or circumferentially relative to the substrate 102) around or along the substrate edge 104 and/or notch so as to polish different portions of the substrate edge 104 and/or notch. In some embodiments, one or more of the heads 110 may be adapted to continuously or intermittently oscillate between the various positions. Alternatively, one or more of the heads 110 may be fixed and/or only adjusted while the substrate 102 is not being rotated. In yet other embodiments, the substrate 102 may be held fixed while one or more of the heads 110 oscillate (as described above) as well as rotate circumferentially around the substrate 102. This movement may be under the direction of a programmed or user operated controller 112, described below. Different heads 110 may be used for different substrates 102 or different types of substrates 102.
As described above, the system 100 may further include the controller 112, (e.g., a programmed computer, a programmed processor, a microcontroller, a gate array, a logic circuit, an embedded real time processor, etc.), which may control the driver(s) used to rotate the substrate 102 and/or the actuator(s) used to push a polisher (
As mentioned above, substrate polishing may be performed using one or more polishing apparatuses 108. In one or more embodiments, a plurality of polishing apparatuses 108 may be employed, in which each polishing apparatus 108 may have similar or different characteristics and/or mechanisms. In the latter case, particular polishing apparatuses 108 may be employed for specific operations. For example, one or more polishing apparatuses 108 may be adapted to perform relatively rough polishing and/or adjustments while another one or more polishing apparatus 108 may be adapted to perform relatively fine polishing and/or adjustments. Polishing apparatuses 108 may be used in sequence so that, for example, a rough polishing procedure may be performed initially and a fine polishing procedure may be employed subsequently as needed or according to a polishing recipe. The plurality of polishing apparatuses 108 may be located in a single chamber or module, as shown herein, or alternatively, one or more polishing apparatuses 108 may be located in separate chambers or modules. Where multiple chambers are employed, a robot or another type of transfer mechanism may be employed to move substrates between the chambers so that polishing apparatuses 108 in the separate chambers may be used in series or otherwise.
In one or more embodiments, the abrasive component of the polishing tape 226 may be made from many different materials, such as diamond, aluminum oxide, silicon oxide, silicon carbide, etc. Other materials may also be used. In some embodiments, abrasives used may range, for example, from about 0.1 microns up to about 10 microns in size or, for example, 0.5 microns to 3 microns in size, although other sizes may be used. Different widths of polishing tape 226 ranging from about 0.2 inches to about 1.5 inches may be used, although other polishing tape widths may be used. In one or more embodiments, the polishing tape 226 may be about 0.002 to about 0.02 inches thick and withstand about 1 to 5 lbs. in tension. Other polishing tapes having different thicknesses and tensile strengths may be used. The take-up and supply spools 232, 234 may have a diameter of approximately 10 inches and be capable of holding about 35,000 inches of polishing tape 226, or may have a diameter of approximately 4 inches and be capable of holding about 5,000 inches of polishing tape 226. Other spool dimensions may be used. The take-up and supply spools 232, 234 may be constructed from materials such as nylon, polyurethane, polyvinyl difluoride (PVDF), etc. Other materials may also be used.
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However, in some embodiments, during the polishing process instead of moving the entire polishing head 400 about the substrate 102, the polishing head 400 is maintained a pre-defined distance, such as 1 mm, for example, from the substrate 102, and the polishing unit 404 may pivot/move/extend/retract to contact and polish the substrate 102, as indicated by the dotted lines. The angle 410 may change as the polishing unit 404 moves to polish the substrate 102. As the polishing unit 404 moves from the balanced position, the angle 410 may increase from zero degrees, for example, and thus the net tension force T may increase and have a greater affect on the force P, as the tension force T has a component that opposes the force P. In some embodiments, the angle 410 may vary in a range of about 0 to about 4 degrees, for example. In this range, the force P may be affected very little by the tension force T. Other suitable ranges may be used. Additionally, because the angle 410 may vary in a smaller range than in the exemplary apparatus 300 shown in
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The foregoing description discloses only exemplary embodiments of the invention. Modifications of the above disclosed apparatus and methods which fall within the scope of the invention will be readily apparent to those of ordinary skill in the art.
Accordingly, while the present invention has been disclosed in connection with exemplary embodiments thereof, it should be understood that other embodiments may fall within the spirit and scope of the invention, as defined by the following claims.
Claims
1. An apparatus comprising:
- a polishing head, adapted to contact a substrate, wherein the polishing head includes: a polishing unit comprising a polisher and at least one pair of tension distributors positioned to reduce tension on the polisher; and one or more pairs of feed guides.
2. The apparatus of claim 1 wherein the polishing head is adapted to pivot about an edge of the substrate.
3. The apparatus of claim 2 wherein the polishing head is adapted to maintain a balanced position while the polishing head pivots about the edge of the substrate.
4. The apparatus of claim 3 wherein the balanced position provides for an angle between the feed guides and the tension distributors to be substantially zero.
5. The apparatus of claim 1 wherein the polishing unit is adapted to pivot about an edge of the substrate, and the polishing head is adapted to maintain a fixed position relative to the polishing unit as the polishing unit pivots about the substrate edge.
6. The apparatus of claim 1 wherein the polisher is adapted to press a polishing tape against the substrate.
7. The apparatus of claim 6 wherein the polishing head includes two pairs of feed guides.
8. The apparatus of claim 7 wherein the feed guides are in a stationary location with respect to the polishing head.
9. The apparatus of claim 7 wherein the polishing tape is routed through a first pair of feed guides, through the polishing unit and then a second pair of feed guides.
10. The apparatus of claim 9 wherein the polishing unit and first and second pairs of feed guides are adapted to receive the polishing tape while remaining coupled to the polishing head.
11. The apparatus of claim 1 wherein the polisher, tension distributors and feed guides are adapted to rotate.
12. The apparatus of claim 1 further comprising a plurality of fasteners adapted to couple the tension distributors to the polishing unit.
13. A system comprising:
- a substrate support adapted to rotate a substrate;
- a polishing head, adapted to contact a substrate, wherein the polishing head comprises: a polishing unit comprising a polisher and at least one pair of tension distributors adapted to reduce tension on the polisher, and one or more pairs of feed guides; and
- a controller adapted to operate the polishing head.
14. The system of claim 13 wherein the controller is adapted to move the polishing head into a balanced position relative to an edge of a substrate.
15. The system of claim 14 wherein the balanced position provides for an angle between the feed guides and the tension distributors to be substantially zero.
16. The system of claim 14 wherein the controller is adapted to move the polishing unit relative to the polishing head.
17. The system of claim 13 wherein the polisher is adapted to press a polishing tape against the substrate.
18. The system of claim 17 wherein the polishing head includes two pairs of feed guides.
19. The system of claim 18 wherein the polishing tape is routed through a first pair of feed guides, through the polishing unit and then a second pair of feed guides.
20. A method comprising:
- rotating a substrate;
- selecting a balanced position for a polishing head;
- contacting the substrate with a polishing film, whereby the polishing film is routed through the polishing head;
- applying a force to the substrate via the polishing film; and
- pivoting the polishing head about the substrate.
21. The method of claim 20 wherein the polishing head comprises:
- a polishing unit comprising a polisher and at least one pair of tension distributors adapted to reduce tension on the polisher.
22. The method of claim 21 wherein the polishing head further comprises:
- one or more pairs feed guides.
23. The method of claim 22 further comprising:
- pivoting the polishing unit about an edge of the substrate.
24. The method of claim 23 further comprising:
- maintaining a fixed position of the polishing head relative to the polishing unit as the polishing unit pivots about the edge of the substrate.
Type: Application
Filed: Oct 22, 2009
Publication Date: Apr 29, 2010
Applicant: APPLIED MATERIALS, INC. (Santa Clara, CA)
Inventors: Gary C. Ettinger (Cupertino, CA), Wendy Luo (Cupertino, CA), Antoine P. Manens (Sunnyvale, CA)
Application Number: 12/603,858
International Classification: B24B 9/02 (20060101); B24B 21/02 (20060101); B24B 21/20 (20060101);