Browse Prior Art Database

Method for Design of Structures Having Any Desired Critical Area

IP.com Disclosure Number: IPCOM000050641D
Original Publication Date: 1982-Nov-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 3 page(s) / 57K

Publishing Venue

IBM

Related People

Ferris-Prabhu, AV: AUTHOR

Abstract

A method is provided wherein metal maze structures, with any desired critical area, used in integrated circuit technology for monitoring bipolar and other semiconductor device yields may be readily designed. Maze designs are provided with known fault probabilities that allow more accurate determination of defect size distributions.

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Method for Design of Structures Having Any Desired Critical Area

A method is provided wherein metal maze structures, with any desired critical area, used in integrated circuit technology for monitoring bipolar and other semiconductor device yields may be readily designed. Maze designs are provided with known fault probabilities that allow more accurate determination of defect size distributions.

The method provides for the design of monitors for the determination of open pattern or shorted pattern limited yield and to reproduce functional patterns more faithfully than heretofore known. The method also provides for the selection, out of several patterns of equivalent functionality, that pattern which is likely to have highest yield or, equivalently, the lowest possibility of fail.

The yield of a pattern is unity minus the probability of failure of that pattern. The probability of failure, i.e., of an open or short, for example, due to a defect of a given size, is the ratio of the critical region, i.e., the region in which that defect must fall if it is to cause a fail, to the region in which that defect can fall. The critical region or critical interval is a complex function of the defect size, and of the geometry of the pattern. No method is presently known for the computation of the critical interval for an arbitrary pattern, i.e., a pattern of arbitrary shape. To approximate a functional pattern, it is customary to construct patterns called mazes, which are repetitive patterns of metal lines with metal interdigitations deposited over the entire surface of a portion of a test site on a semiconductor wafer. The width of the metal lines and the spacing between them are very important in obtaining an accurate measure of the probability of the occurrence of a fail, i.e., of an open or of a short. Until now, there has been no method known for the computation of the critical interval for a repetitive pattern in which there are more than two spacings between the loops of a given metal line as it winds back and forth across the test site maze area. As a consequence, mazes have been and are being constru...