Wafer-Level Array Camera Alignment via Spacer Bonding
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Solution Overview
Problem
Existing wafer-level camera manufacturing methods require individual alignment of each image sensor with respect to a lens, which is time-consuming and complex, whereas the proposed method aligns an image sensor wafer with a lens wafer in a single step, simplifying the process by using a spacer to maintain the optical pathway between lenses and image sensors.
Innovation Solution
A wafer-level array camera is fabricated by disposing a lens wafer with a lens array on an image sensor wafer, using a spacer to maintain the optical alignment, and then dicing the composite wafer to form individual cameras, allowing all image sensors to be aligned in one step, thereby simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If individual alignment of each image sensor with respect to a lens is performed, then alignment precision is achieved, but manufacturing complexity and time increase significantly
Solution Approach 1:
The patent merges multiple individual alignment operations into a single wafer-level alignment operation. By keeping image sensors and lenses on their respective wafers during alignment, the entire array can be aligned simultaneously using wafer bonding techniques, eliminating the need for repetitive individual sensor-lens alignment and significantly reducing manufacturing complexity
Solution Approach 2:
The patent performs preliminary positioning of image sensors and lenses on their respective wafers before final bonding. This preliminary action allows for pre-alignment and verification at the wafer level, ensuring that when the wafers are bonded together, the alignment precision is maintained without requiring complex individual adjustment mechanisms
2Length of stationary object
If wafer-level manufacturing is used to reduce camera height, then compactness is achieved, but the imaging lens covers less area in the image plane
Solution Approach 1:
The patent segments the imaging system into multiple lens arrays, each covering a specific region of the image sensor array. By dividing the lens array into multiple segments that correspond to different regions of the image sensor, the system achieves both compact wafer-level manufacturing and complete coverage of the image plane
Solution Approach 2:
The patent transitions from a single-lens configuration to a multi-lens array configuration arranged in a two-dimensional pattern that matches the image sensor array. This dimensional arrangement allows each lens to cover a specific region while collectively covering the entire image plane, maintaining compact height through wafer-level integration
3Area of stationary object
If multiple extra lenses are added to cover additional image plane area, then image coverage is improved, but device complexity increases
Solution Approach 1:
The patent designs a universal lens array structure where multiple lenses are arranged in a systematic pattern that can be manufactured using the same wafer-level processes. This universal design allows the lens array to cover the entire image plane while maintaining manufacturing simplicity through standardized fabrication techniques
Solution Approach 2:
The patent combines multiple lenses into a single integrated lens array wafer that is bonded to the image sensor wafer. By merging the multiple lens elements into a unified wafer-level structure, the system achieves complete image plane coverage without the complexity of assembling and aligning individual lenses separately
Data Source
AI summary
A wafer-level array camera includes (i) an image sensor wafer including an image sensor array, (ii) a spacer disposed on the image sensor wafer, and (iii) a lens wafer disposed on the spacer, wherein the lens wafer includes a lens array. A method for fabricating a plurality of wafer-level array cameras includes (i) disposing a lens wafer, including a plurality of lens arrays, on an image sensor wafer, including a plurality of image sensor arrays, to form a composite wafer and (ii) dicing the composite wafer to form the plurality of wafer-level array cameras, wherein each of the plurality of wafer-level array cameras includes a respective one of the plurality of lens arrays and a respective one of the plurality of image sensor arrays.