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Wafer map pattern recognition is instrumental for detecting systemic manufacturing process issues. However, high cost in labeling wafer patterns renders it impossible to leverage large amounts of valuable unlabeled data in conventional machine learning based wafer map pattern prediction. We proposed a contrastive learning framework for semi-supervised learning and prediction of wafer map patterns. Our framework incorporates an encoder to learn good representation for wafer maps in an unsupervised manner, and a supervised head to recognize wafer map patterns. In particular, contrastive learning is applied for the unsupervised encoder representation learning supported by augmented data generated by different transformations (views) of wafer maps. We identified a set of transformations to effectively generate similar variants of each original pattern. We further proposed a novel rotation-twist transformation to augment wafer map data by rotating each given wafer map for which the angle of rotation is a smooth function of the radius. Experimental results demonstrate that the proposed semi-supervised learning framework greatly improves recognition accuracy compared to traditional supervised methods, and the rotation-twist transformation further enhances the recognition accuracy in both semi-supervised and supervised tasks.
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WaferCap: Open Classification of Wafer Map Patterns using Deep Capsule Network
In integrated circuit design, analysis of wafer map patterns is critical to enhance yield and detect manufacturing issues. With the emergence of novel wafer map patterns, there is increasing need for robust artificial intelligence models that can both accurately classify seen patterns and while also detecting ones not seen during training, a capability known as open world classification. We develop a novel solution to this problem: WaferCap, a Deep Capsule Network designed for wafer map pattern classification and equipped with a rejection mechanism. When evaluated using the WM-811k dataset, WaferCap significantly surpasses existing methods, achieving 99\% accuracy for fully seen patterns while demonstrating robust performance in open-world settings by effectively detecting unseen wafer map patterns.
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- Award ID(s):
- 2008167
- PAR ID:
- 10570103
- Publisher / Repository:
- IEEE
- Date Published:
- ISBN:
- 979-8-3503-6378-4
- Page Range / eLocation ID:
- 1 to 7
- Format(s):
- Medium: X
- Location:
- Tempe, AZ, USA
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1109/VTS60656.2024.10538764
