Image Sensor Package Layout for Flare and Peeling Control
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Solution Overview
Problem
The existing image sensor packages face issues with flare phenomena and peeling of the surface layer due to overlapping light absorption layers and bonding structures, which generate stress from differences in thermal expansion coefficients.
Innovation Solution
An image sensor package design featuring a photo absorption layer with a specific pattern protruded towards the bonding structure, minimizing overlap and maximizing coverage between the microlens array and the bonding structure, thereby preventing delamination and improving noise from flare effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a light absorption layer is formed on the outer portion of the image sensor chip to prevent flare, then flare prevention is improved, but stress concentration and peeling occur due to overlap with bonding structure and CTE difference
Solution Approach 1:
The light absorption layer is segmented into a first light absorption layer and a second light absorption layer with different material compositions. The first light absorption layer is positioned closer to the bonding structure and has a CTE matched to the bonding structure, while the second light absorption layer is positioned farther away and has a CTE matched to the substrate. This segmentation allows each layer to handle different stress conditions, preventing peeling while maintaining flare prevention.
Solution Approach 2:
The material composition and CTE of the light absorption layer are changed at different positions. By adjusting the CTE parameter of the light absorption layer to match either the bonding structure or the substrate depending on the position, the stress concentration is reduced and peeling is prevented while maintaining the light absorption function.
2Object-affected harmful factors
If the light absorption layer extends close to the bonding structure to maximize flare prevention, then flare prevention is improved, but stress concentration increases due to CTE difference between materials
Solution Approach 1:
Different regions of the light absorption layer have different material properties. The first light absorption layer near the bonding structure has a CTE matched to the bonding structure to reduce stress, while the second light absorption layer farther away has a CTE matched to the substrate. This local quality variation allows the light absorption layer to extend close to the bonding structure for maximum flare prevention without causing stress concentration.
3Reliability
If the light absorption layer is positioned far from the bonding structure to reduce stress, then peeling resistance is improved, but flare prevention effectiveness is reduced
Solution Approach 1:
The light absorption layer is divided into two segments: the first light absorption layer positioned close to the bonding structure for stress management, and the second light absorption layer positioned farther away for optimal flare prevention. This segmentation allows both peeling resistance and flare prevention to be optimized simultaneously.
Solution Approach 2:
The CTE parameter of the light absorption layer is changed at different positions to match different reference materials. This parameter change allows the light absorption layer to be positioned optimally for flare prevention while maintaining peeling resistance through stress management.
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
The solution effectively prevents peeling of the surface layer and reduces noise caused by flare phenomena by optimizing the pattern of the photo absorption layer, ensuring reliable operation of the image sensor chip.
Implementation Method 1
a light absorption layer for preventing reflected light is formed on the outer portion of the image sensor chip to prevent the flare
Implementation Method 2
a stress may be generated due to a difference in coefficients of thermal expansion (CTE) between materials thereof
Data Source
AI summary
An image sensor package according to an embodiment includes: an image sensor chip having a sensing area of a central part and an outer area surrounding the sensing area; a transparent substrate spaced apart from and above the image sensor chip and covering the image sensor chip; a bonding structure disposed between the image sensor chip and the transparent substrate and provided on an upper surface of the outer area; and a package substrate on which the image sensor chip is mounted and electrically connected to the image sensor chip, wherein the image sensor chip, on a plane, includes a photo absorption layer enclosing the edge of the sensing area and having a pattern protruded toward the bonding structure along a circumference.