Substrate Bonding Alignment With Chromatic Aberration Correction
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Solution Overview
Problem
Existing bonding apparatuses face challenges in achieving precise alignment and bonding of substrates with varying thicknesses and materials due to chromatic aberration and material changes affecting alignment mark detection.
Innovation Solution
The bonding apparatus incorporates imaging units and radiation units to capture images of alignment marks, utilizing white light of varying wavelengths and spectrometry to correct for chromatic aberration, ensuring accurate alignment and bonding through a controller that adjusts the relative positions of the substrates based on reflection intensity and wavelength relationships.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If white light radiation is used for imaging alignment marks, then imaging capability is improved, but chromatic aberration causes alignment precision to deteriorate
Solution Approach 1:
The patent changes the wavelength parameter of the radiation light from broad-spectrum white light to specific wavelengths (e.g., 405 nm violet light or 635 nm red light) that match the sensitivity peak of the imaging sensor. This parameter optimization eliminates chromatic aberration while maintaining high imaging capability, thereby resolving the contradiction between illumination intensity and alignment precision.
2Productivity
If alignment mark detection is performed without wavelength correction, then detection speed is improved, but alignment precision deteriorates due to material variations
Solution Approach 1:
The patent performs preliminary action by pre-determining the optimal wavelength for imaging based on the substrate material properties and sensor characteristics. This wavelength information is stored and automatically applied during alignment mark detection, eliminating the need for real-time wavelength correction while maintaining high alignment precision across different substrate materials.
3Manufacturing precision
If multiple imaging units with different wavelengths are used, then alignment precision is improved, but device complexity increases
Solution Approach 1:
The patent makes the single imaging unit universal by optimizing it to work effectively with specific wavelength radiation. The imaging unit is designed to have peak sensitivity at predetermined wavelengths, allowing it to function accurately across different substrate materials without requiring multiple specialized imaging units, thus maintaining simplicity while achieving high alignment precision.
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 enhances alignment precision and ensures stable, precise bonding of substrates by correcting for chromatic aberration and material variations, improving the quality of the bonding process.
Implementation Method 1
a first radiation unit configured to radiate white light to an imaging area of the first imaging unit... a first imaging unit configured to image the second substrate held by the second holder
Implementation Method 2
corrects the detected position of the first alignment mark based on a relationship between a wavelength and an intensity of reflection light reflected from the first substrate
Data Source
AI summary
A bonding apparatus bonds a first substrate having a first alignment mark and a second substrate having a second alignment mark. A first radiation unit radiates white light to an imaging area of a first imaging unit when the second alignment mark is imaged by the first imaging unit. A second radiation unit radiates white light to an imaging area of a second imaging unit when the first alignment mark is imaged by the second imaging unit. A controller detects positions of the first alignment mark and the second alignment mark by processing images obtained by the first imaging unit and the second imaging unit, corrects the detected position of the first alignment mark based on a relationship between a wavelength and an intensity of reflection light reflected from the first substrate, and controls a moving unit based on the corrected position of the first alignment mark.