Frontside Image Sensor Light-Scattering Structure for Pixel Cross-Talk
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Solution Overview
Problem
Conventional CMOS image sensors experience cross-talk between adjacent pixels due to light reflection or refraction, leading to inefficient light utilization and reduced light sensitivity, particularly in the near-infrared range.
Innovation Solution
A frontside illuminated image sensor with a light scattering portion in the substrate, featuring a center section and side sections of varying depths to increase the light path and focus incident light on the photoelectric conversion structure, preventing cross-talk and enhancing light sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the pitch of individual unit pixels is reduced to increase pixel density, then the quantity of pixels increases, but light reflection or refraction causes cross-talk between adjacent pixels, reducing measurement precision
Solution Approach 1:
The patent divides the substrate into isolated pixel regions by introducing light scattering portions between adjacent pixels. This segmentation prevents light from one pixel from interfering with adjacent pixels, thereby eliminating cross-talk while maintaining high pixel density.
Solution Approach 2:
The light scattering portion acts as an intermediary element positioned between adjacent pixels. It scatters incident light to prevent direct transmission to neighboring pixels, serving as a mediator that blocks harmful light interference while allowing each pixel to function independently.
2Ease of manufacture
If conventional flat substrate structure is used, then manufacturing is simple, but light path is short and light sensitivity is insufficient, particularly in near infrared range
Solution Approach 1:
The patent introduces vertical depth variation into the substrate by creating light scattering portions with different depths (first depth and second depth). This dimensional change extends the light path vertically, increasing light sensitivity without complicating the horizontal manufacturing process.
Solution Approach 2:
The patent changes the depth parameter of the light scattering portions to optimize light sensitivity. By adjusting the depth values (first depth and second depth) of different light scattering portions, the light path length is controlled to enhance near-infrared detection capability while maintaining manufacturing feasibility.
3Ease of manufacture
If light scattering portion has uniform depth, then manufacturing is simplified, but light cannot be effectively focused on photoelectric conversion structure, reducing light sensitivity
Solution Approach 1:
The patent applies different depth values to different light scattering portions based on their local requirements. The first light scattering portion has a first depth while the second light scattering portion has a second depth, optimizing light focusing for different regions and enhancing overall light sensitivity.
Solution Approach 2:
The patent introduces asymmetry in the light scattering portion depths to achieve better light focusing. The asymmetric depth configuration (different first depth and second depth) creates optimized light paths that concentrate light more effectively on the photoelectric conversion structure compared to uniform depth designs.
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 light scattering design effectively prevents cross-talk between pixels, increases light sensitivity, and simplifies the manufacturing process by allowing different light paths for various color channels, while maintaining a compact image sensor size.
Implementation Method 1
a light scattering portion in a substrate configured to increase a path of incident light
Implementation Method 2
including a light scattering portion with a relatively deep side section and a relatively shallow center section in the substrate to converge or focus the incident light on a photoelectric conversion structure
Data Source
AI summary
Disclosed are a frontside illuminated image sensor and a method of manufacturing the same. More particularly, a frontside illuminated image sensor and a method of manufacturing the frontside illuminated image sensor include a light scattering portion in a substrate, configured to increase a path of incident light, thereby preventing cross-talk between adjacent pixels and increasing light sensitivity.