Fabry-Perot Filter Wafer Cutting With Thinned Mirror Regions
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Solution Overview
Problem
Manufacturing Fabry-Perot interference filters is challenging due to difficulties in improving both manufacturing efficiency and yield.
Innovation Solution
A method involving forming thinned regions in mirror layers and sacrificial layers on a wafer, using laser light to create modified regions for cutting, and etching to remove sacrificial layers, while employing stress adjustment layers to prevent damage and warping, thus enhancing manufacturing efficiency and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional manufacturing methods are used for Fabry-Perot interference filters, then manufacturing process simplicity is maintained, but both manufacturing efficiency and yield cannot be improved
Solution Approach 1:
The manufacturing process is divided into distinct sequential steps: forming thinned regions in mirror and sacrificial layers, removing sacrificial portions through etching, forming modified regions via laser irradiation, and cutting the wafer. This segmentation allows each step to be optimized independently, improving overall manufacturing efficiency while maintaining process control
Solution Approach 2:
Thinned regions are formed in the mirror layers and sacrificial layers before the cutting step. This preliminary action prevents damage to the delicate mirror layers during subsequent cutting operations, thereby improving yield without significantly increasing process complexity
2Manufacturing precision
If laser light is used to form modified regions for cutting, then cutting precision is improved, but laser scattering occurs reducing reliability
Solution Approach 1:
Thinned regions are formed at specific locations where laser irradiation will occur. This local modification of the layer structure at the cutting lines reduces laser scattering and absorption, ensuring reliable laser processing while maintaining full layer integrity in the filter regions for high cutting precision
Solution Approach 2:
The thinned regions act as intermediaries that facilitate laser light transmission and modification. By creating these localized thin regions, the laser can effectively form modified regions for cutting without excessive scattering, improving both precision and reliability
3Strength
If complete mirror layers are maintained throughout the wafer, then layer integrity is preserved, but damage occurs during cutting operations
Solution Approach 1:
Instead of modifying the entire wafer structure, thinned regions are created only at the specific locations where cutting will occur. This localized approach maintains full layer integrity in the filter regions while creating vulnerable points only where needed for cutting, preventing unwanted damage
Solution Approach 2:
The wafer structure is segmented into regions with different thickness characteristics: full-thickness regions for filter functionality and thinned regions for cutting. This segmentation allows the cutting process to affect only the thinned regions while leaving the delicate mirror layers intact in the filter areas
4Productivity
If sacrificial layers are removed before cutting, then gap formation efficiency is improved, but layer damage risk increases
Solution Approach 1:
Thinned regions are formed in advance before sacrificial layer removal and cutting. This preliminary structural preparation ensures that when sacrificial layers are later removed to form gaps, the mirror layers are already protected at critical locations, maintaining reliability while allowing efficient gap formation
Solution Approach 2:
The thinned regions serve as a protective cushioning structure that prevents damage to mirror layers during the sacrificial layer removal process. By having this protective structure in place beforehand, the etching process can proceed efficiently without risking mirror layer damage
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
The method improves manufacturing efficiency and yield by preventing laser scattering, damage to layers, and warping, allowing for precise cutting and efficient gap formation between mirrors.
Implementation Method 1
a modified region within the wafer along each of the lines is formed through irradiation of a laser light and extending a crack in a thickness direction of the wafer from the modified region
Implementation Method 2
scattering or the like of a laser light is prevented so that the modified region can be reliably formed within the wafer
Data Source
AI summary
A method of manufacturing a Fabry-Perot interference filter includes a forming step of forming a first thinned region, a first mirror layer, a sacrificial layer, and a second mirror layer are formed on a first main surface of a wafer, and the first thinned region in which at least one of the first mirror layer, the sacrificial layer, and the second mirror layer is partially thinned along each of a plurality of lines is formed; a cutting step of cutting the wafer into a plurality of substrates along each of the plurality of lines by forming a modified region within the wafer along each of the plurality of lines through irradiation of a laser light, after the forming step; and a removing step of removing a portion from the sacrificial layer through etching, between the forming step and the cutting step or after the cutting step.