Wafer Level Image Sensor Module Packaging
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Solution Overview
Problem
Conventional image sensor module packaging methods, such as the COB process, face challenges including low production rate, high defective rates due to dust, high costs for clean room maintenance, and limitations in microminiaturization, which hinder the downsizing and mass manufacturing of compact image sensor modules.
Innovation Solution
A wafer level image sensor module manufacturing method that involves sorting image sensor chips and lens modules by quality grade, aligning them, and using an encapsulation material to surround the lens modules, which reduces module height and volume, and eliminates the need for additional shading masks or materials, thereby improving production yield and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If COB process is used to package image sensor modules, then image sensor chips can be directly installed on substrate, but production rate is low and defective rate is high due to unit level packaging and dust introduction
Solution Approach 1:
The patent merges multiple image sensor chips and lens modules onto a single substrate simultaneously using wafer-level packaging, combining what were previously separate unit-level packaging operations into one consolidated process, thereby increasing production rate while maintaining manufacturing simplicity
Solution Approach 2:
The patent segments the substrate into multiple regions, each dedicated to housing specific image sensor chips and lens modules in a systematic array, enabling parallel processing and assembly of multiple components simultaneously rather than sequential unit-level packaging
2Ease of manufacture
If COB process is used to package image sensor modules, then image sensor chips can be directly installed on substrate, but high defective rate is caused by dust introduced during the process
Solution Approach 1:
The patent employs a controlled clean room environment with restricted access and positive pressure to maintain a dust-free atmosphere during wafer-level packaging operations, preventing dust contamination that would cause defects while preserving process simplicity
3Reliability
If COB process is used to package image sensor modules, then image sensor chips can be directly installed on substrate, but high cost is incurred for building and maintaining clean rooms
Solution Approach 1:
The patent changes the scale of packaging from unit-level to wafer-level, processing multiple chips simultaneously in fewer clean room cycles, thereby reducing the cumulative cost of maintaining clean room environments while maintaining low defective rates through controlled environment packaging
4Ease of manufacture
If conventional packaging methods are used, then image sensor modules can be assembled, but height and volume are large preventing microminiaturization
Solution Approach 1:
The patent transitions from three-dimensional stacked assembly to a planar wafer-level integration approach, arranging image sensor chips and lens modules in a two-dimensional array on the substrate, thereby reducing module height and enabling microminiaturization while simplifying the assembly process
5Reliability
If additional shadow masks or shading materials are used to block stray light, then image sensing performance can be improved, but device complexity and material consumption increase
Solution Approach 1:
The patent designs the substrate to serve multiple functions: it acts as both the mounting platform for image sensor chips and lens modules and as the shading structure that blocks stray light, eliminating the need for separate shadow masks and reducing device complexity while maintaining image sensing performance
6Reliability
If additional shadow masks or shading materials are used to block stray light, then image sensing performance can be improved, but manufacturing cost and material consumption increase
Solution Approach 1:
The substrate is designed to simultaneously serve as the structural platform for mounting components and as the shading element that blocks stray light, eliminating the need for additional shading materials and reducing material consumption while maintaining image sensing performance
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 approach enhances production yield by ensuring better assembly of high-quality components, reduces material consumption and costs, simplifies the manufacturing process, and improves image sensing performance by blocking stray light, making the modules more suitable for mass production and compact electronic devices.
Implementation Method 1
an encapsulation material surrounding the wafer level lens module blocks light from entering the image sensor chip through a lateral of the wafer level lens module
Data Source
AI summary
This present invention discloses a manufacturing method and structure for a wafer level image sensor module with fixed focal length. The method includes the following steps. First, a silicon wafer comprising several image sensor chips having a photosensitive area and a lens module array wafer comprising several wafer level lens modules with fixed focal length are provided. Next, the image sensor chips and the wafer level lens modules are sorted in grades according to the different quality grades. According to the sorting results, each of the wafer level lens modules is assigned to be situated above the image sensor chip that has the same grade. At the same time, each of the wafer level lens modules is directed to face the photosensitive area of each image sensor chip. Finally, in the packaging process, the wafer level lens module is surrounded by an encapsulation material.