Image Sensor Micro Lens and Protective Pattern Segmentation
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Solution Overview
Problem
Existing image sensor manufacturing processes face challenges in minimizing image defects and simplifying the production process, particularly in forming color filters and micro lens layers without causing striation defects or height differences that can affect image accuracy.
Innovation Solution
The image sensor design includes a substrate with a pixel region, pad region, and optical black region, featuring a micro lens layer and protective patterns made from the same transparent material, which are separated to reduce stress and simplify the manufacturing process, and a method involving etching and photolithography to form convex lens portions and protective patterns, ensuring accurate formation of color filters and minimizing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single-layer lens structure is used to cover both pad region and pixel region, then the manufacturing process is simplified, but stress concentration and image defects occur during chip division
Solution Approach 1:
The lens layer is segmented into two separate structures: a first protective pattern covering the pad region and a micro lens layer covering the pixel region. This segmentation allows each layer to be optimized independently - the protective pattern prevents stress concentration at pad regions during chip division, while the micro lens layer maintains focusing functionality, thereby resolving the contradiction between manufacturing simplicity and image quality reliability
2Productivity
If color filters and micro lens layers are formed using conventional processes, then production is efficient, but striation defects and height differences occur affecting image accuracy
Solution Approach 1:
The formation of color filters and micro lens layers is merged into a single integrated process step. By forming both structures simultaneously using the same photolithography and reflow processes, the patent eliminates striation defects and height differences that would otherwise require separate processing steps, thereby maintaining high productivity while achieving superior manufacturing precision
3Adaptability or versatility
If protective patterns and micro lens layer are made from different materials, then functional requirements are met, but manufacturing complexity and material compatibility issues arise
Solution Approach 1:
The protective pattern and micro lens layer are formed from the same transparent resin material, creating a homogeneous structure. This homogeneity simplifies the manufacturing process by eliminating material compatibility issues and interface problems, while the structural differentiation (protective pattern vs. lens portions) maintains the necessary functional adaptability for both stress protection and optical focusing
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 design enhances image sensor reliability by reducing image defects and simplifying the manufacturing process, improving the accuracy of color filters and micro lens formation, and preventing stress-related issues during chip division.
Implementation Method 1
The photodiode may convert incident light into an electrical signal
Implementation Method 2
a micro lens layer on the second surface of the substrate in the pixel region
Data Source
AI summary
An image sensor includes a substrate including a pixel region and a pad region, a first conductive pad on the substrate in the pad region, a micro lens layer on the substrate in the pixel region, and a first protective pattern covering the pad region and exposing the first conductive pad. The first protective pattern and the micro lens layer include the same material, and the first protective pattern and the micro lens layer are apart from each other.