Reliability Assessment of a Semiconductor Memory by Design Analysis

The proliferation of new processes, designs and materials now appearing within the confines of what used to be a discrete part package has made the design review an essential tool to the user of modern complex LSI circuits. The functional and circuit detail of a 1024 bit, field programmable, read-only memory is reviewed as an example of an LSI device with many unique features, as well as a device which has, in the past, experienced a unique failure mode (program recovery). All of the memory circuits are covered, however the three main elements essential to establishing and maintaining the program are emphasized. These elements are 1) the nichrome resistor programming element, 2) the circuit that develops and delivers the programming pulse and 3) the process and construction of the programming circuit.