Robert HerrickEdwardsville, IL

5259925, Nov 9, 1993

Jun 5, 1992

7/894479

Robert W. Herrick - Hazelwood MO
Joseph L. Levy - University City MO
Danny J. Krebs - Arnold MD

McDonnell Douglas Corporation - St. Louis MO

H01L 21302
B44C 122

1566591

A method for cleaving semiconductor devices along planes accurately positioned. Resist is applied to a major surface of the semiconductor device and a mask is projected upon the resist covered major surface. The mask is opaque in those regions in which no cleave is desired. Following the exposure of the resist, the removal of the mask and the development of the resist, an ion beam is positioned incident upon the semiconductor surface such that ion beam etching occurs in the areas in which no resist covers the semiconductor structure. Once a sufficient depth is etched in the areas not covered with resist such that the strength of the semiconductor structure in those areas is significantly less than in those areas covered by resist, the ion beam etching process is ended and the resist is stripped from the semiconductor structure. Subsequently, force is applied within the area in which the ion beam etching occurred to cleave the semiconductor structure within that region. Such cleaving may occur either prior or subsequent to etching of facets for the semiconductor devices.

5460034, Oct 24, 1995

Jul 21, 1992

7/917546

Robert W. Herrick - Hazelwood MO

The United States of America as represented by the Secretary of the Air
Force - Washington DC

G01N 2700
H01J 3726

73105

A scanning electron microscope is used to scan the etched facet edge to produce digital data representative of its profile. A Fourier transform of the edge profile is produced and the resulting plurality of spatial frequency components can be used to generate a first low frequency waveform component indicative of lack of precise edge definition, a midrange frequency component indicative of poor liftoff samples, and a high frequency component indicative of metal grain size. A tilt adjustment feature of the electron microscope is optionally used to advantageously magnify the shape of the profile in the y direction.