Radiant energy – Irradiation of objects or material – Irradiation of semiconductor devices
Patent
1976-05-03
1978-04-18
Smith, Alfred E.
Radiant energy
Irradiation of objects or material
Irradiation of semiconductor devices
250491, G01N 2134
Patent
active
040853292
ABSTRACT:
The specification describes a process wherein short wavelength or "hard" x-rays (less than about 4 Angstroms) are used to align a semiconductor processing mask with a semiconductor wafer without the requirement for thinning the wafer to permit the x-rays to pass through. These short wavelength x-rays may be obtained from either the continuum x-rays which accompany the "soft" (longer wavelength) characteristic x-rays used for resist exposure, or from a specialized source of hard x-rays. Alternatively, alignment marks may be provided on the surface of the wafer to project alignment-indicative fluorescent x-rays onto an x-ray detector without passing through the underlying semiconductor wafer. A null condition in the intensity of the "hard" x-rays, or the fluorescent x-rays in the alternative embodiment of the invention, which are received at an x-ray detector is indicative of an alignment between a reference mark on the mask and either a reference mark or an opening on the wafer.
REFERENCES:
patent: 3417243 (1968-12-01), Hill
patent: 3742229 (1973-06-01), Smith et al.
patent: 3743842 (1973-07-01), Smith et al.
patent: 3920984 (1975-11-01), Kirkendall et al.
McCoy John H.
Sullivan Paul A.
Anderson B. C.
Bethurum William J.
Hughes Aircraft Company
MacAllister W. H.
Smith Alfred E.
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