Claims
- 1. The method of making a precise pattern on a substrate, comprising the steps of:
- (a) forming a first layer on said substrate,
- (b) forming a second layer on the first layer,
- (c) forming a photo-resist layer on the second layer,
- (d) exposing the photo-resist layer with means to form said pattern, followed by a developing process which selectively removes part of the photo-resist layer to expose openings of said pattern,
- (e) removing the second layer in said openings,
- (f) using air blasting with an abrasive powder to remove the first layer in said openings, with the photo-resist and the second layer acting together as a mask;
- the improvement wherein for step (f) a special elongated nozzle and scanning provides substantially uniform abrasion over the entire exposed surface of said first layer, wherein the nozzle has an exit which is relatively long in one dimension and narrow in the orthogonal dimension to provide a substantially uniform velocity of the abrasive powder along the long dimension, and the scanning of the pattern-substrate structure with respect to the nozzle comprises successive passes in a direction generally perpendicular to the long dimension of the projection of the nozzle.
- 2. The method as claimed in claim 1, wherein said nozzle adapts a standard cylindrical air erosion gun for uniform erosion, the nozzle having an approximately constant cross-sectional area from its cylindrical entrance to its exit.
- 3. The method as claimed in claim 2, wherein said exit of the nozzle is rectangular.
- 4. The method as claimed in claim 1, wherein there is a periodic 90 degree rotation of the pattern-substrate structure with respect to the nozzle between scanning passes.
- 5. The method as claimed in claim 4, wherein said exit of the nozzle is rectangular.
- 6. The method as claimed in claim 5, wherein said nozzle adapts a standard cylindrical air erosion gun for uniform erosion, the nozzle having an approximately constant cross-sectional area from its cylindrical entrance to its rectangular exit.
- 7. The method as claimed in claim 6, wherein said powder is Al.sub.2 O.sub.3.
- 8. The method as claimed in claim 1, wherein said first layer is principally BN formed by chemical vapor deposition.
- 9. The method as claimed in claim 8, wherein said step (b) comprises forming said second layer from the group of metals comprising W and Mo, using chemical vapor deposition from the metal carbonyl.
- 10. The method as claimed in claim 8, including the further step after step (f) of removing the remainder of the photo-resist.
- 11. The method as claimed in claim 8, wherein said abrasive powder is Al.sub.2 O.sub.3.
Parent Case Info
This is a division of application Ser. No. 037,258, filed May 9, 1979 now U.S. Pat. No. 4,237,209.
Government Interests
The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalties thereon or therefore.
US Referenced Citations (6)
Divisions (1)
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Number |
Date |
Country |
Parent |
37258 |
May 1979 |
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