Optical Rib Formation for Stable Movable Unit Control
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Solution Overview
Problem
Existing optical devices face challenges in accurately forming rib portions to suppress deformation of movable units and elastic support portions during movement, which affects the controllability and integrity of the device.
Innovation Solution
A method for manufacturing optical devices involves a two-stage etching process using resist layers as masks to form rib portions with precision, ensuring the rib portions are thinner than the base semiconductor layer, thereby preventing protrusion and deformation, and supporting the movable unit's movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a rib portion is provided to the movable unit or elastic support portion to suppress deformation during movement, then the structural stability is improved, but the manufacturing precision deteriorates due to difficulty in accurately forming the rib portion
Solution Approach 1:
The patent applies segmentation by dividing the etching process into two distinct stages: a first etching step that creates a depression in the first semiconductor layer, and a second etching step that forms the rib portion by etching through the depression to the insulating layer. This segmentation allows each step to be controlled independently, with the first resist layer masking the base region and the second resist layer defining the rib portion geometry, thereby achieving both structural stability and manufacturing precision
Solution Approach 2:
The patent employs preliminary action by first forming a depression in the first semiconductor layer before creating the rib portion. This preliminary depression serves as a pre-prepared structure that guides the subsequent rib formation process, ensuring that the rib portion is formed with accurate dimensions and position relative to the base, thus resolving the manufacturing precision issue while maintaining structural stability
2Reliability
If the first semiconductor layer constituting the rib portion is made thinner than the base, then the rib portion protection is improved by preventing protrusion, but the structural strength deteriorates
Solution Approach 1:
The patent applies local quality by making the first semiconductor layer thickness non-uniform: the rib portion region has a thinner first semiconductor layer (etched down to the insulating layer) while the base region maintains the full thickness. This local thinning provides the desired protection and prevents protrusion at the rib portion, while the thicker base maintains overall structural strength. The insulating layer serves as a stopping layer to control the etching depth and ensure the rib portion does not become too thin
Solution Approach 2:
The patent uses the insulating layer as an intermediary element between the first and second semiconductor layers. By etching the first semiconductor layer down to the insulating layer at the rib portion, the insulating layer acts as a protective mediator that prevents complete removal of the first semiconductor layer, thereby maintaining minimum structural strength while still achieving the thinning effect needed for protection and preventing protrusion
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 accurate formation of rib portions, enhancing the protection and stability of optical function units, reducing deformation, and maintaining precise control over the movable unit's movement.
Implementation Method 1
forming a first resist layer in a region corresponding to the base on a surface of the first semiconductor layer which is opposite to the insulating layer
Implementation Method 2
forming a depression in the first semiconductor layer by etching the first semiconductor layer up to an intermediate portion in a thickness direction using the first resist layer as a mask
Implementation Method 3
forming a second resist layer in a region corresponding to the 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
Data Source
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AI summary
A method for manufacturing an optical device includes: a first step of preparing a semiconductor substrate that includes a portion corresponding to a base, a movable unit, and an elastic support portion; a second step of 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; a third step of forming a depression in the first semiconductor layer by etching the first semiconductor layer up to an intermediate portion in a thickness direction using the first resist layer as a mask; a fourth step of 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 a fifth step of forming the rib portion by etching the first semiconductor layer until reaching the insulating layer using the second resist layer as a mask.