Moiré Grating Alignment for High-Density Bonding Pads
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Solution Overview
Problem
Current methods for aligning bonding pads with bonding locations in electronic devices lack accuracy and speed, especially as device sizes decrease and pad density increases, necessitating a method that does not rely on alignment features.
Innovation Solution
The method involves using a grating system where a first grating is positioned relative to the interconnect contacts on a chip, and a moiré pattern is measured to adjust the position of the chip chuck relative to a substrate chuck, allowing for precise alignment without alignment features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If alignment features are used to align bonding pads with bonding locations, then alignment accuracy can be maintained, but device complexity increases and the method becomes unsuitable for high-density miniaturized devices
Solution Approach 1:
The patent removes alignment features from the bonding process entirely. Instead of using separate alignment markers or features, the system directly uses the interconnect contacts themselves as the alignment reference by superimposing their optical images, thereby simplifying the device structure while maintaining alignment accuracy
Solution Approach 2:
The patent combines the alignment function with the interconnect contacts themselves. The contacts serve dual purposes: both as electrical interconnects and as alignment references. By superimposing the optical images of contacts from both devices, the system achieves alignment without requiring separate alignment features
2Productivity
If traditional alignment methods are used, then alignment can be performed, but alignment speed is insufficient for high-speed bonding requirements
Solution Approach 1:
The patent replaces mechanical alignment methods with optical image superposition. By using optical images of the interconnect contacts and superimposing them through image processing, the system achieves both high speed and high precision alignment, eliminating the need for slow mechanical adjustment procedures
3Area of moving object
If device size decreases and pad density increases, then device integration improves, but alignment accuracy becomes more difficult to achieve
Solution Approach 1:
The patent creates optical copies (images) of the interconnect contacts and uses these copies for alignment purposes. By capturing and superimposing optical images of the contacts from both devices, the system can accurately align even miniaturized high-density devices without direct physical contact or complex measurement procedures
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables fast and accurate alignment of interconnect contacts, achieving precision that is a fraction of the pad diameters, even in high-density and miniaturized electronic devices.
Implementation Method 1
measuring a first moiré pattern of the first grating and the set of interconnect contacts
Implementation Method 2
measuring the measurement radiation that has diffracted off the set of interconnect contacts
Data Source
AI summary
A system and method for holding a chip on a chip chuck. The chip has a set of interconnect contacts. The system and method includes positioning a first grating relative to the set of interconnect contacts. The system and method includes measuring a first moiré pattern of the first grating and the set of interconnect contacts. The system and method includes adjusting position of the chip chuck relative to a substrate chuck based on the first moiré pattern.