Wafer Bonder Feedback Control for Overlay Distortion Mitigation
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Solution Overview
Problem
Traditional methods for controlling bonding tools to minimize overlay distortions in wafer pairs are outdated and unable to account for new adjustment technologies, leading to reliability concerns and potential electrical discontinuities.
Innovation Solution
A system and method that includes a wafer shape metrology sub-system for measuring pre- and post-bonding wafers, a controller to apply a bonder control model to measured distortions, and provide feedback adjustments to the bonding tool to maintain tolerance limits, using algorithms like PCA to generate orthogonal wafer signatures for precise adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional control methods are used for bonding tools, then the system is simple and easy to operate, but overlay distortion patterns occur and manufacturing precision deteriorates
Solution Approach 1:
The patent implements a feedback control system where wafer shape measurements are taken before and after bonding, the differences are analyzed to determine distortion patterns, and control adjustments are automatically applied to the bonding tool to correct these patterns. This closed-loop feedback mechanism enables precise overlay control while adapting to various distortion types.
Solution Approach 2:
The system changes control parameters by adjusting bonding tool settings based on measured distortion patterns. The control system modifies parameters such as wafer positioning, bonding pressure distribution, and heating profiles to compensate for identified distortion patterns, thereby maintaining manufacturing precision.
2Reliability
If traditional bonder control models are used, then the model is simple, but it cannot account for new adjustment technologies and reliability deteriorates
Solution Approach 1:
The control model is designed to be dynamic and adaptive rather than static. It continuously updates based on measured distortion patterns from wafer shape measurements, allowing the model to adapt to different bonding scenarios, tool conditions, and distortion types. This dynamic approach ensures reliability while accommodating new adjustment technologies.
Solution Approach 2:
The control model segments the bonding process into distinct measurement and correction phases. Wafer shape measurements are taken at multiple stages (pre-bonding and post-bonding), and the control model processes these segmented measurements to identify specific distortion patterns and apply targeted corrections, improving reliability through systematic analysis.
3Manufacturing precision
If no feedback control is implemented, then the system is simple and fast to operate, but overlay distortion patterns occur and manufacturing precision deteriorates
Solution Approach 1:
The bonding tool incorporates self-service capabilities through automated feedback control. The system automatically measures wafer shapes, analyzes distortion patterns, determines appropriate corrections, and adjusts bonding parameters without requiring manual intervention. This self-regulating mechanism maintains high precision while keeping operations straightforward.
Solution Approach 2:
The system replaces manual mechanical adjustment methods with automated measurement and control systems. Instead of relying on operator skill and manual tool adjustments, the patent uses automated wafer shape measurement and computer-controlled parameter adjustments to achieve precise overlay control, simplifying operation while maintaining high precision.
Data Source
AI summary
A system includes a wafer shape metrology sub-system configured to perform one or more shape measurements on post-bonding pairs of wafers. The system includes a controller communicatively coupled to the wafer shape metrology sub-system. The controller receives a set of measured distortion patterns. The controller applies a bonder control model to the measured distortion patterns to determine a set of overlay distortion signatures. The bonder control model is made up of a set of orthogonal wafer signatures that represent the achievable adjustments. The controller determines whether the set of overlay distortion signatures associated with the measured distortion patterns are outside tolerance limits provides one or more feedback adjustments to the bonder tool.