Unsupervised novelty pattern classification of shmoo plots for visualizing the test results of integrated circuits

Hyun Soo Shin, Youngju Kim, Chang Ouk Kim, Sung Ho Park

Research output: Contribution to journalArticlepeer-review


Shmoo plots are visual tools for verifying the performance of integrated circuit devices, where each cell in a plot records whether the examined device operates normally under the test condition. When identifying the device state, the overall pass/fail pattern appearing in the shmoo plot is more important than the test results for individual conditions. Because similar shmoo plots indicate similar device characteristics, defect causes, and process peculiarities, engineers can analyze device quality and defect causes by classifying shmoo plot patterns. Most mass-produced devices have high and stable yields, whereas defect devices are incredibly scarce. If engineers classify numerous device plots manually at a semiconductor test site, significant time and resources will be required, and the result will likely vary based on the engineers’ experience. Therefore, shmoo plot usage is limited unless an automatic classification model is adopted. Moreover, training high-performance pattern classifiers that do not overfit the models is difficult because shmoo plots contain high-dimensional data and unlabeled, multiclass imbalanced datasets, where the number of defects is smaller than that of normal plots and pattern labels are seldom assigned. In this study, we propose a novel feature extraction process and a two-stage clustering process to distinguish novel shmoo plot patterns. Actual shmoo plots obtained from a wafer test stage are used to compare the experimental results obtained via the proposed method and conventional methods, and they verify the superiority of the proposed method.

Original languageEnglish
Article number117341
JournalExpert Systems with Applications
Publication statusPublished - 2022 Sept 15

Bibliographical note

Funding Information:
This work was supported by the National Research Foundation of Korea (NRF), South Korea grant funded by the Korean government (MSIT) (NRF-2022R1A2B5B01001889) and Institute of Convergence Science (ICONS), Yonsei University, South Korea.

Publisher Copyright:
© 2022 Elsevier Ltd

All Science Journal Classification (ASJC) codes

  • Engineering(all)
  • Computer Science Applications
  • Artificial Intelligence


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