Backside Illuminated Image Sensor Light Blocking Trenches
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Solution Overview
Problem
CMOS image sensors face interference between adjacent pixels due to slanting light incidence, which affects sensing efficiency.
Innovation Solution
The implementation of a light blocking layer filled in trenches along the boundary of pixels on a semiconductor substrate, using a metal layer or color filter material, to prevent light from interfering with adjacent pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a light blocking layer is added to block slanting light and reduce pixel interference, then sensing efficiency is improved, but device complexity increases
Solution Approach 1:
The patent merges the light blocking layer with the color filter layer into a single integrated structure. The color filter layer serves dual functions: filtering specific wavelengths of light for color detection and blocking slanting light to prevent pixel interference. This integration eliminates the need for separate light blocking structures, thereby improving sensing efficiency without significantly increasing device complexity.
Solution Approach 2:
The color filter layer is designed to perform multiple functions simultaneously: it acts as both a wavelength-selective filter for color detection and a light blocking barrier to prevent crosstalk between adjacent pixels. By making the color filter layer universal in its functionality, the patent achieves improved sensing efficiency while avoiding the added complexity of separate dedicated light blocking structures.
2Productivity
If a light blocking layer is added to block slanting light and reduce pixel interference, then sensing efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The patent combines the formation of the light blocking layer with the existing color filter layer deposition process. Both functions are achieved in a single manufacturing step by integrating the light blocking material into the color filter layer structure, thereby improving sensing efficiency without adding significant manufacturing complexity.
Solution Approach 2:
The color filter layer is designed to simultaneously provide wavelength filtering and light blocking capabilities. By making the color filter layer multi-functional, the patent achieves improved sensing efficiency while using the same manufacturing processes already in place for color filter fabrication, thus avoiding additional manufacturing complexity.
3Ease of manufacture
If the light blocking layer is integrated with the color filter layer, then manufacturing process is simplified, but device complexity increases
Solution Approach 1:
The patent merges the light blocking function into the color filter layer, creating an integrated structure that performs both functions. This integration simplifies the manufacturing process by eliminating separate fabrication steps for dedicated light blocking structures, while the dual-functionality of the merged layer manages device complexity through functional consolidation rather than additive complexity.
Solution Approach 2:
The color filter layer is designed as a universal component that simultaneously provides wavelength-selective filtering and slanting light blocking. This multi-functionality approach simplifies manufacturing by using a single layer for multiple purposes, while managing device complexity through efficient functional integration rather than adding separate components.
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 solution enhances sensing efficiency by effectively blocking slanting light and reducing pixel interference, while also simplifying the manufacturing process by integrating the light blocking layer with existing color filter layers.
Implementation Method 1
trenches formed in a second surface of the semiconductor substrate along a boundary of a pixel, and a light blocking layer in the trenches
Data Source
AI summary
Disclosed are an image sensor and a manufacturing method thereof. The image sensor includes a circuit layer on a first surface of a semiconductor substrate, a metal interconnection layer on the circuit layer, trenches formed in a second surface of the semiconductor substrate along a boundary of a pixel, and a light blocking layer in the trenches. The backside illumination type image sensor according to the embodiment has a light blocking structure at a rear surface of the semiconductor substrate, thereby improving sensing efficiency while inhibiting interference between adjacent pixels.