Bonding Head Orientation Using Multi-Image Pad Alignment
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Solution Overview
Problem
Current methods for aligning bonding pads on chiplets lack the speed and accuracy required as the size of chiplets and pads decrease and density increases, necessitating a fast and precise alignment without relying on alignment features.
Innovation Solution
A bonding system utilizing a microscope to generate multiple images of chiplet bonding pads, estimate orientation, and adjust positioning based on these images, incorporating a rotatable optical element and optical subsystems to enhance alignment precision and speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional alignment methods using alignment features are used, then alignment can be performed with current technology, but alignment accuracy and speed are insufficient for decreasing pad sizes and increasing density
Solution Approach 1:
The patent replaces mechanical alignment features with an optical imaging system. A microscope captures images of bonding pads, and image processing algorithms determine pad positions and orientations. This substitution of mechanical features with optical-mechanical systems enables higher precision alignment (fraction of pad diameter) while maintaining high speed processing through automated image analysis.
2Manufacturing precision
If alignment features are used on chiplets, then alignment can be performed, but the method becomes inadequate as pad size decreases and density increases
Solution Approach 1:
The patent extracts the alignment function from physical alignment features on chiplets and transfers it to an external imaging and processing system. By removing the dependency on alignment features being present on the chiplets themselves, the system becomes adaptable to high-density configurations where adding alignment features would be difficult or impossible.
Solution Approach 2:
The imaging system serves multiple functions: it captures images for alignment, measures pad positions, determines orientations, and provides feedback for positioning adjustments. This multi-functional approach replaces the single-purpose alignment features with a versatile system that handles all alignment requirements regardless of pad density or size.
3Measurement precision
If multiple images are captured from different states, then orientation estimation accuracy improves, but processing time increases
Solution Approach 1:
The system captures multiple images of bonding pads from different microscope states (positions or orientations) before final bonding occurs. These preliminary images are processed to estimate pad orientations and positions, which then guide the positioning system to make precise adjustments. This preliminary action enables accurate orientation determination without requiring time-consuming adjustments during the actual bonding process.
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
Enables accurate and rapid alignment of chiplet bonding pads with sub-micron precision, facilitating efficient bonding processes even with complex chiplet configurations.
Implementation Method 1
a rotatable optical element located between the first optical subsystem and the second optical subsystem configured to be at a first angle when the microscope is in the first state and configured to be at a second angle when the microscope is in the second state
Data Source
AI summary
A bonding system configured to bond a chiplet to a destination site and method of using the bonding system. The bonding system comprises a bonding head configured to hold the chiplet and a microscope. The microscope is configured to: generate a first image of a first subset of the plurality of chiplet bonding pads with the microscope in a first state; and generate a second image of a second subset of the plurality of chiplet bonding pads with the microscope in a second state. The bonding system may also comprise a processor configured to estimate a first orientation of the chiplet based on the first image and the second image. The bonding system may also comprise a positioning system configured to adjust the chiplet and the destination site relative to each other based on the first orientation. The bonding head is configured to bond the chiplet to the destination site.