Progress in improvement in size and density of semiconductor memory devices has been astonishing in recent years. Redundancy techniques are indispensable to improve product yield in which defective memory cells, when discovered, are replaced by spare cells. This replacement is performed by programming on-chip devices. So far, laser cutting1 or electrical conductor (fuse) cutting2 has been used. However, these methods damage the passivation layers. A conductor connecting technique by laser irradiation is being developed so that a new redundancy technique3 can be used.
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