Optical Device Rib Formation for Deformation Control
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Solution Overview
Problem
Existing methods for manufacturing optical devices with rib portions on movable units or elastic support portions struggle with accuracy, leading to deformation issues and difficulties in forming these features with precision.
Innovation Solution
A method involving a semiconductor substrate with a first and second semiconductor layer and an insulating layer, where the rib portion is formed using a two-stage etching process with resist layers, ensuring the rib portion is thinner than the base and allowing for precise formation and protection against protrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rib portion is provided to suppress deformation of the movable unit or elastic support portion, then deformation is suppressed and reliability is improved, but the rib portion protrudes from the base causing potential damage to optical function units
Solution Approach 1:
The patent applies parameter changes by controlling the thickness of the first semiconductor layer to be non-uniform: thinner in the rib portion region and thicker in the base region. This thickness parameter variation allows the rib portion to be formed with precise height control, suppressing deformation while preventing protrusion that could damage optical function units.
Solution Approach 2:
The patent implements local quality by creating different thickness characteristics of the first semiconductor layer at different locations: the rib portion has a thinner first semiconductor layer while the base has a thicker first semiconductor layer. This local differentiation enables the rib to provide structural support without excessive height that could cause damage.
2Manufacturing precision
If a rib portion is formed with precise thickness control, then manufacturing precision is improved and deformation is suppressed, but the manufacturing process complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the etching process into two distinct stages: first etching the first semiconductor layer to form the rib portion with controlled thickness, then etching the second semiconductor layer. This segmentation allows precise control of the rib portion thickness while maintaining a manageable manufacturing process through clear process separation.
Solution Approach 2:
The patent implements preliminary action by first forming the rib portion with the desired thickness control before proceeding to subsequent etching steps. The first semiconductor layer is etched to the appropriate depth first, establishing the rib structure, and then the second semiconductor layer is etched. This preliminary formation ensures precise rib dimensions are achieved before additional processing.
Data Source
AI summary
A method for manufacturing an optical device includes: preparing a semiconductor substrate that includes a portion corresponding to a base, a movable unit, and an elastic support portion; forming a first resist layer in a region corresponding to the base on a surface of a first semiconductor layer which is opposite to an insulating layer; forming a depression in the first semiconductor layer by etching the first semiconductor layer using the first resist layer as a mask; forming a second resist layer in a region corresponding to a rib portion on a bottom surface of the depression, a side surface of the depression, and the surface of the first semiconductor layer which is opposite to the insulating layer; and forming the rib portion by etching the first semiconductor layer until reaching the insulating layer using the second resist layer as a mask.