Semiconductor device manufacturing: process – Chemical etching – Combined with the removal of material by nonchemical means
Reexamination Certificate
2007-03-29
2008-11-04
Pham, Thanh V (Department: 2823)
Semiconductor device manufacturing: process
Chemical etching
Combined with the removal of material by nonchemical means
C438S697000, C438S704000, C438S734000, C257SE21303, C257SE21304
Reexamination Certificate
active
07446045
ABSTRACT:
In an independent GaN film manufactured by creating a GaN layer on a base heterosubstrate using vapor-phase deposition and then removing the base substrate, owing to layer-base discrepancy in thermal expansion coefficient and lattice constant, warp will be a large ±40 μm to ±100 μm. Since with that warp device fabrication by photolithography is challenging, reducing the warp to +30 μm to −20 μm is the goal. The surface deflected concavely is ground to impart to it a damaged layer that has a stretching effect, making the surface become convex. The damaged layer on the surface having become convex is removed by etching, which curtails the warp. Alternatively, the convex surface on the side opposite the surface having become convex is ground to generate a damaged layer. With the concave surface having become convex due to the damaged layer, suitably etching off the damaged layer curtails the warp.
REFERENCES:
patent: 1426497 (2003-06-01), None
patent: H08-321445 (1996-12-01), None
patent: 2000-084807 (2000-03-01), None
Judge James W.
Pham Thanh V
Sumitomo Electric Industries Ltd.
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