LSI technology

Now, at the beginning of the 80s, questions arise about VLSI (Very Large Scale Integration). For the first time since the invention of the integrated circuit, some doubt is shown by people in charge of the management of the IC industry. The first limitation appears when design of excessively complex circuits are required-how to ensure that the designed circuit will work exactly as required, particularly as far as timing is concerned? More severe limitations arise from testing. Since there is no easy access to internal nodes of the circuit, the complete validity of the chip has to be checked from the input and output, which is far from an easy job in view of the numbers of possible events in the circuit. But perhaps more drastic will be the fact that, from an economic point of view, only a few functions or systems seem-at least for the moment-to be suitable for integration at VLSI level. Memories and microprocessors and well-defined functions in great demand, will be the first VLSI functions. But after that there is some doubt on the functions that will justify the formidable investment of a VLSI chip design. The author discusses some of the technological steps on an IC development, namely mask-making and silicon processing.Anglai