The spidermask: a new approach for yield monitoring using product adaptable test structures

An approach for yield monitoring based on a test vehicle that consists of structures, built on the underground of a high volume product is described. A specially designed metal mask, called spidermask, together with its appropriate contact mask, isolates and contacts these individual structures to create a complete yield monitor set. The major advantage of this type of structure is the close relationship between the measurement results on the test structure itself and the actual performance of the corresponding product. As a consequence, the existing yield model is adapted to conform to the yield monitor data. The spidermask was implemented in a CMOS and in a mixed bipolar-CMOS technology. The data of both yield monitors are presented, and the relationship with the yield model is demonstrated.<>