Plated-wire memories--Problems and progress

Plated magnetic film wire memory elements must remain cost competitive with alternate memory elements or they will disappear from the commercial market. Substantial progress toward this goal is continuing in four areas. 1) High capacity memory modules with 5000 bits per square inch, or more, are being developed. 2) Use of new tests and substrate preparation processes make possible 50 bits per inch of wire on 2.5 mil diameter wire. 3) Plating process improvements make stable, repeatable high yield possible. Peak yield of 90% to 95% and large volume yield of 45% to 55% have been achieved. 4) Better understanding and new tests for disturb phenomena avoid design and performance problems. Automatic memory array test equiment provides economical high precision testing.