Date of this Version
Published in: IEEE Spectrum ( Volume: 22, Issue: 4, April 1985 )
Most engineers would agree that the quality of an integrated circuit depends partly on the ability to test it. But many chips now hold over 10,000 devices, and the cost of testing tends to increase in proportion to the square of the number of devices on the chip. The problem of containing testing costs while ensuring chip quality is one that all semiconductor manufacturers face.
If the line width of a semiconductor device shrinks from 2 micrometers to 1, the number of devices on a die of equal size could quadruple. Thus, the time—and the money—required to develop a computer program to test this chip could increase sixteenfold. Rising costs of chip testing run counter to the recent reductions in the cost of designing and producing chips.
Testing now accounts for 10 percent of the total cost of manufacturing a 1-kilobit random-access-memory chip. For a 64-K RAM chip, the figure rises to 40 percent. New techniques, however, promise help in the struggle to hold down costs, by tackling the circuit-testing problem in the design stage.