Direct-Bond Hybridization for Optical Sensor Integration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for integrating solid-state optical elements with electro-optical sensors, such as Bayer filters, are prone to rework issues, damage, and high costs due to laborious alignment and vertical gaps, with low yield and risk of defects in high-value sensors.
Innovation Solution
A direct-bond hybridization (DBH) method where optical elements are fabricated on a handle wafer, with oxides of specific thicknesses deposited and transferred using a DBH fusion bond technique to a sensor wafer, eliminating the need for expensive mounting and allowing for rework and improved yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If solid-state optical elements are deposited directly on a sensor, then integration is achieved, but the structure is not amenable to rework and high-value parts are at risk of damage or failure
Solution Approach 1:
The patent divides the optical element fabrication and sensor assembly into separate stages. Optical elements are fabricated on a handle wafer first, then transferred to the sensor wafer via direct-bond hybridization. This segmentation allows the optical elements to be manufactured and tested separately before final integration, enabling rework if defects are found without damaging the high-value sensor.
2Ease of operation
If discrete optical elements are aligned and mounted in an optical chain, then optical functionality is achieved, but the process is laborious and requires expensive bezel materials
Solution Approach 1:
The patent merges the optical element fabrication with the sensor wafer processing by using direct-bond hybridization. Instead of separately mounting discrete optical elements with complex alignment and expensive bezels, the optical elements are transferred directly onto the sensor wafer surface, simplifying the mounting process and eliminating the need for expensive mounting structures.
3Manufacturing precision
If discrete optical elements are mounted with alignment, then optical precision is achieved, but a vertical gap is created that is detrimental to imaging
Solution Approach 1:
The patent extracts the optical element from its traditional mounted position and transfers it directly onto the sensor wafer surface using direct-bond hybridization. This eliminates the vertical gap that would otherwise exist between mounted optical elements and the sensor, removing the harmful factor while maintaining precise optical alignment.
4Ease of manufacture
If Bayer filters are applied using photolithography/lift-off process, then filter application is achieved, but photolithography defects and processing lift-off debris reduce yield
Solution Approach 1:
The patent uses an intermediary handle wafer for fabricating and testing Bayer filters before transferring them to the final sensor wafer. This intermediary approach allows defects to be identified and corrected on the handle wafer using photolithography/lift-off processes without risking damage to the high-value sensor, thereby improving overall processing yield.
5Manufacturing precision
If photolithography/lift-off process is used for Bayer filters, then filter patterning is achieved, but the risk of defects is unacceptable for high-value sensors
Solution Approach 1:
The patent performs preliminary fabrication and testing of Bayer filters on a handle wafer before transferring them to the high-value sensor wafer. This preliminary action allows all photolithography-related defects to be identified and corrected in advance, eliminating the risk of defects on expensive sensors while maintaining precise filter patterning.
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 method enables efficient fabrication of optical elements on a separate wafer, reducing cycle time, eliminating the need for expensive mounting structures, and ensuring high-quality integration with sub-micron alignment, while minimizing defects on high-value assets by processing on a temporary handle wafer.
Implementation Method 1
executing layer transfer of the optical element by a DBH fusion bond technique to the sensor wafer whereby the first and second oxides form an oxide layer of n thickness between the optical element and the sensor wafer
Data Source
AI summary
A direct-bond hybridization (DBH) method is provided to assemble a sensor wafer device. The DBH method includes fabricating an optical element on a handle wafer and depositing first oxide with n-x thickness on the optical element where n is an expected final oxide thickness of the sensor wafer, depositing second oxide with x thickness onto a sensor wafer, executing layer transfer of the optical element by a DBH fusion bond technique to the sensor wafer whereby the first and second oxides form an oxide layer of n thickness between the optical element and the sensor wafer and removing the handle wafer.