Method and apparatus for covering a multilayer process space during at-speed testing
AssigneeInternational Business Machines Corporation
InventorsYiyu Shi, Chandramouli Visweswariah, Jinjun Xiong, Vladimir Zolotov
Life of this patent
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Abstract
In one embodiment, the invention is a method and apparatus covering a multilayer process space during at-speed testing. One embodiment of a method for selecting a set of paths with which to test a process space includes determining a number N of paths to be included in the set of paths such that at least number M of paths in N for which testing of the process space will fail, computing a metric that substantially ensures that the set of paths satisfies the requirements of N and M, and outputting the metric for use in selecting the set of paths.
Claims25
A method for selecting a set of paths with which to test a process space, the method comprising:
- determining a number N of paths to be included in the set of paths, where each of the N paths has an associated path slack;
- determining a least number M of paths in N for which testing of the process space will fail;
- computing a metric that substantially ensures that the set of paths satisfies the requirements of N and M;
- and
- outputting the metric for use in selecting the set of paths.
A method for defining multilayer coverage of a process space for a given set of N path slacks, the method comprising:
- receiving a least number M of paths in N for which testing of the process space will fail;
- defining the multilayer coverage as a probability that a set of paths associated with the set of N path slacks will fail testing;
- and
- outputting the metric.
A method for computing a metric to define a process space covered M times by a set of N path slacks {S1, . . . , SN}, the method comprising:
- computing a first value as a first portion process space covered M times by a subset of the set of N path slacks {S1, . . . , SN−1};
- computing a second value as a joint space of a second portion process space covered by a last path slack SN of the set of N path slacks and a third portion of the process space covered M−1 times by the subset of the set of N path slacks{S1, . . . , SN};
- summing the first value and the second value to produce the metric;
- and
- outputting the metric.
A method for computing a metric to define a process space covered M times by a set of N path slacks {S1, . . . , SN}, the method comprising:
- recursively computing a function fN,k(·) as a kth smallest path slack in the set of N path slacks;
- computing the metric as a probability that the function fN,k(·) is less than or equal to a minimum allowable path slack;
- and
- outputting the metric.
Dependencies are inferred from the claim text.