Method of reducing wafer particles after partial saw
First Claim
1. A method of fabricating a monolithic device from a wafer, comprising the steps of:
- a) partially fabricating the device by depositing a first and second layer of photoresist on the wafer, wherein said first and second layers are compatible with each other, with a structure disposed therebetween;
b) partially sawing the wafer to form kerfs; and
c) cleansing the device with a solution of buffered hydrofluoric acid (HF) having a concentration of at least 1%, wherein said compatible first and second photoresist layers prevent the HF solution from permeating the second photoresist layer and damaging the structure.
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Abstract
A method of fabricating a monolithic device, preferably a micromechanical device, from a wafer (20) by carefully selecting the composition of two or more layers of photoresist (52,54). The present invention comprises choosing compatible photoresist layers to avoid generating defects in the layers of photoresist which could allow a wet chemical HF acid etch process to damage an underlying micromechanical device. The present invention allows a very strong solution of hydrofluoric acid to be utilized to remove particles and debris after a partial-saw process, and to remove a damaged portion of an underlying CMOS layer (22) at a region (68) proximate a kerf (62). Using an HF solution having a concentration of about 6% is desired. The present invention substantially improves the yield of micromechanical devices.
31 Citations
12 Claims
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1. A method of fabricating a monolithic device from a wafer, comprising the steps of:
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a) partially fabricating the device by depositing a first and second layer of photoresist on the wafer, wherein said first and second layers are compatible with each other, with a structure disposed therebetween; b) partially sawing the wafer to form kerfs; and c) cleansing the device with a solution of buffered hydrofluoric acid (HF) having a concentration of at least 1%, wherein said compatible first and second photoresist layers prevent the HF solution from permeating the second photoresist layer and damaging the structure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification