Analyzing the risk of timing modeling based on path delay tests.

Abstract

As technology scales, it is becoming increasingly difficult for simulation and timing models to accurately predict silicon timing behavior. When a collection of chips fail in timing in a similar way, diagnosis and silicon debug look to find the root-causes for the failure. However, little work has been done to develop a methodology that looks for useful design information in the good-chip data. This paper describes a path-based methodology that correlates measured path delays from the good chips, to the path delays predicted by timing analysis. We explain how to utilize this methodology for evaluating the risk of timing modeling.

Diagnosis of design-silicon timing mismatch with feature encoding and importance ranking - the methodology explained

“…The methodology was first introduced in [4] with the emphasis on the explanation of the learning algorithm, in particular the Support Vector Machine (SVM) classifier. The features were based on cells and wires and the kernel function used to interpret them was fixed.…”

“…As mentioned in the Introduction, previous works [3,4] focused the study on the learning algorithm, i.e. how and what algorithms should be used for learning and how to rank features.…”

“…how and what algorithms should be used for learning and how to rank features. The work in [5] improves the SVM classifier algorithm used in [3,4] with the ε-insensitive Support Vector Regression (ε-SVR) algorithm [27]. Although these works were important for developing the overall diagnosis methodology, they also raise questions regarding the applicability of the proposed approach in practice.…”

“…All previous works [3,4,5] use cells and groups of wires as features. In practice, the concerns can go beyond just cells and wires.…”

“…As we allow feature definition to go beyond wires and cells, the feature ranking method in [3,4,5] needs to be generalized as well. This is because the previous ranking method depends on the fact that all feature values can be interpreted in a certain way.…”