Title :
Laser coding of bipolar read-only memories
Author :
North, James C. ; Weick, Walter W.
fDate :
8/1/1976 12:00:00 AM
Abstract :
Laser beam coding of high-speed bipolar silicon integrated circuit memories is described. Coding is accomplished by the selective vaporization of Ti-Pt links connecting the contact pads of each memory cell to Ti-Pt-Au bit lines. Vaporized link resistances of >10/SUP 9/ Ω can be consistently obtained, with no melting of the adjacent gold patterns. Parameters that have been found to be relevant to the link vaporization process are described including the number of laser pulses per link, beam spot size, thickness of the gold metallization, and pulse energy. The laser coding process is especially useful for applications where relatively small numbers of chips of each of many codes are needed, since only one photolithographic mask set is required.
Keywords :
Digital integrated circuits; Laser beam applications; Monolithic integrated circuits; Read-only storage; Semiconductor storage devices; digital integrated circuits; laser beam applications; monolithic integrated circuits; read-only storage; semiconductor storage devices; Gold; Laser beam cutting; Laser beams; Metallization; Optical pulses; Pulsed laser deposition; Read only memory; Semiconductor laser arrays; Silicon; Temperature;
Journal_Title :
Solid-State Circuits, IEEE Journal of
DOI :
10.1109/JSSC.1976.1050766
