Manufacturing GaAs digital ICs with 100 mm substrates-the smooth transition

The strategy, implementation, and difficulties associated with the complete conversion of an existing 3-in GaAs digital IC manufacturing line to 100-mm substrates are described. The conversion costs are shown to be almost two orders of magnitude lower than the cost of a new 100-mm manufacturing line with similar capability. The electrical quality of 100-mm substrates is shown to be as good as or better than that of current 3-in materials. This comparison is based on the evaluation of thirty 100-mm boules from eight different manufacturers and thirty 3-in boules from five different manufacturers. The majority of the 100-mm process steps required almost no modification or optimization in order to match the results routinely obtained on 3-in production wafers. One exception was the rapid thermal annealing process, as this process required significant hardware upgrades for optimal results. However, the outcome of these upgrades was an RTA process which completely eliminated slip and wafer distortion following high-temperature annealing. Initial process runs have demonstrated excellent parametric control and uniformity over the full 100-mm wafer surface.<>