Fusing Mechanism of Nichrome-Linked Programmable Read-Only Memory Devices

Abstract

The Programmable Read-Only Memory (PROM) consists of a two-dimensional matrix of nichrome (NiCr) fuses blown in a specific pattern to introduce a digital code. In this application, the reliability of the NiCr fuse can be considered to consist of two parts, that of the unfused and the fused resistor link. The reliability of unblown NiCr registors has been reported as excellent, when the resistors are properly fabricated and operated within well-defined specifications .[1,2,3] t The reliability of blown resistors is directly related to the probability of healing or "growback" occurring. [4] However, this can be minimized by fusing the resistors under proper blowing conditions. Although the reliability of fused NiCr resistors has been established, fusing mechanism has not, and is at presentonly speculation.