Semiconductor Light-Receiving Device Asymmetric Sidewall Design
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Solution Overview
Problem
The existing semiconductor light-receiving devices with multiple back-illuminated light-receiving elements face defects in the insulating film due to overlapping sidewalls of concave regions surrounding the lenses, leading to discontinuities in resist coating and potential particle generation during the film formation process.
Innovation Solution
The semiconductor light-receiving device is designed with two lenses on a semiconductor substrate, featuring a concave region with a sidewall height greater than the lens top, where the distance between the sidewall lower edge and the lens center satisfies specific geometric conditions, preventing sidewall overlap and ensuring proper resist coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple lenses are formed on a semiconductor substrate with concave regions surrounding each lens, then the light-receiving elements can be properly positioned and focused, but the sidewalls of adjacent concave regions may overlap causing defects in the insulating film
Solution Approach 1:
The patent applies asymmetry by making the sidewall configuration asymmetric relative to the lens positions. Specifically, the first concave region has a different sidewall arrangement compared to the second concave region, with at least one sidewall positioned at a greater distance from its lens than the corresponding sidewall of the other concave region. This asymmetric design prevents sidewall overlap while maintaining proper lens positioning and focusing capability.
Solution Approach 2:
The patent implements local quality by varying the sidewall distances locally around different lenses. Instead of using a uniform sidewall distance for all concave regions, the design adjusts the sidewall positions locally - some sidewalls are positioned closer to their lenses while others are positioned farther away. This local variation ensures that sidewalls do not overlap between adjacent concave regions while maintaining the necessary structural support for each lens.
2Strength
If the sidewalls of concave regions are positioned close to the lenses, then the structural support is maximized, but the sidewalls may overlap with adjacent sidewalls causing resist coating discontinuity
Solution Approach 1:
The asymmetric sidewall configuration ensures that while sidewalls remain close to their respective lenses for structural support, they do not overlap with adjacent sidewalls. By making the sidewall distances asymmetric - with at least one sidewall positioned at a greater distance than its counterpart - the design maintains structural integrity while enabling uniform resist coating across the substrate surface.
Solution Approach 2:
The local variation in sidewall positioning allows each concave region to maintain optimal structural support with sidewalls close to its lens, while simultaneously ensuring sufficient spacing from adjacent sidewalls. This local quality adjustment - where sidewall distances are optimized individually for each lens position - achieves both structural strength and ease of manufacture with uniform resist coverage.
3Ease of manufacture
If the concave regions are formed with concentric sidewalls at a fixed distance from lens centers, then the manufacturing process is simplified, but sidewall overlap occurs between adjacent lenses
Solution Approach 1:
The patent breaks the symmetric concentric pattern by implementing asymmetric sidewall positioning. Instead of all sidewalls being at the same distance from their respective lens centers, the design specifies that at least one sidewall of one concave region is positioned at a greater distance than the corresponding sidewall of the other concave region. This asymmetric modification prevents sidewall overlap while maintaining relatively simple manufacturing processes.
Solution Approach 2:
The design applies local quality by varying the sidewall distance parameter locally around different lenses. While most sidewalls may maintain a standard distance for manufacturing simplicity, specific sidewalls are positioned at different distances to prevent overlap in critical areas. This localized adjustment maintains ease of manufacture for the majority of the structure while achieving the precision required to prevent sidewall overlap.
Data Source
AI summary
A semiconductor light-receiving device includes two lenses; and a concave region, a height of the sidewall being higher than a top of the lenses, a distance between a position H and a lower edge of the sidewall vertical to a line segment C1 being grater than following condition: {(r+L)2−(W/2)2}1/2 where: C1 is a line segment connecting centers of the lenses; H is a midpoint of the C1; r is a radius of the lenses; W is an interval between the centers; and C2 is a lines passing through the centers in a direction vertical to the C1, wherein: the lower edge of the concave portion in an outer side of a region between the C2 is concentrically formed so as to have a distance of (r+L) from the center of the lenses; and W is following condition: W<2 (r+L).