Metal treatment – Compositions – Heat treating
Patent
1984-06-14
1985-08-13
Roy, Upendra
Metal treatment
Compositions
Heat treating
29574, 29576B, 148187, 357 91, 427 531, H01C 700, H01L 21265, H01L 2166
Patent
active
045348049
ABSTRACT:
A laser beam is used to scribe an alignment mark on the back side of a lightly doped substrate of a silicon wafer containing an heavily doped internal layer. The wavelength of the laser beam is chosen such that it passes through the lightly doped substrate without absorption but is absorbed in the heavily doped internal layer to produce therein a defect which has the same position as the scribed alignment mark. Subsequent heating of the wafer causes the defect to migrate upwardly through a lightly doped epitaxial layer to the front side of the wafer and produce therein a visible mirror image of the scribed alignment mark.
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patent: 3752589 (1973-08-01), Kobayashi
patent: 4046985 (1977-09-01), Gates
patent: 4131487 (1978-12-01), Pearce et al.
patent: 4137100 (1979-01-01), Zaleckas
patent: 4174217 (1979-11-01), Flatley
patent: 4217570 (1980-08-01), Holmes
patent: 4257827 (1981-03-01), Schwuttke et al.
patent: 4318752 (1982-03-01), Tien
patent: 4319119 (1982-03-01), Runge
patent: 4348809 (1982-09-01), Sasaki
patent: 4415373 (1983-11-01), Pressley
International Business Machines - Corporation
Roy Upendra
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