Light-Collimating Layer With Segmented Holes For Biometric Sensors
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Solution Overview
Problem
Existing light collimators in semiconductor devices, particularly in biometric applications, are not satisfactory in maintaining efficient light collimation performance due to issues such as pillar collapse and crosstalk, which affect the resolution and efficiency of identification processes.
Innovation Solution
A semiconductor device with a light-collimating layer comprising multiple light-shielding layers with holes of varying cross-sectional areas and a transparent material layer, where the transparent pillars have a smaller aspect ratio to prevent collapse and enhance collimation performance, thereby reducing light crosstalk and maintaining high resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transparent pillars are made taller to improve collimation performance, then light collimation efficiency is improved, but pillar stability deteriorates leading to collapse
Solution Approach 1:
The light-collimating layer is divided into multiple segments (first light-collimating portion, second light-collimating portion, third light-collimating portion) with different hole diameters. This segmentation allows each portion to contribute differently to light collimation while maintaining overall structural stability, resolving the contradiction between tall pillar performance and stability.
Solution Approach 2:
Different portions of the light-collimating layer are assigned different local qualities (hole diameters d1, d2, d3 where d1>d2>d3). The first portion has larger holes for better light transmission, while the third portion has smaller holes for structural support, creating local quality variations that simultaneously achieve collimation performance and pillar stability.
2Use of energy by moving object
If hole diameter is increased to improve light transmission, then light transmission efficiency is improved, but light crosstalk increases
Solution Approach 1:
The light-collimating layer is segmented into multiple portions with progressively smaller hole diameters. This segmentation creates a gradient structure where light transmission efficiency is optimized in the first portion while crosstalk is suppressed in the third portion with smaller holes, resolving the contradiction between transmission efficiency and crosstalk prevention.
Solution Approach 2:
The hole diameter parameter is changed across different portions of the light-collimating layer (d1>d2>d3). This parameter change creates a gradient that optimizes light transmission in regions where it is needed while reducing crosstalk in regions where structural integrity and signal isolation are priorities.
3Object-generated harmful factors
If multiple light-shielding layers are added to reduce crosstalk, then light crosstalk is reduced, but device complexity increases
Solution Approach 1:
The light-shielding function and light-collimating function are merged into a single integrated light-collimating layer with multiple portions. Instead of adding separate light-shielding layers, the invention combines crosstalk suppression and collimation into one structure, reducing device complexity while maintaining crosstalk reduction effectiveness.
Solution Approach 2:
The light-collimating layer serves multiple functions simultaneously: it collimates light through its multi-portion structure, shields against crosstalk through progressive hole diameter reduction, and maintains pillar stability. This multi-functionality eliminates the need for separate dedicated light-shielding layers, reducing overall device complexity.
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 maintains great collimation performance while preventing pillar collapse, enhancing the resolution and efficiency of light collimation in semiconductor devices, particularly in biometric applications like fingerprint identification devices.
Implementation Method 1
The light collimator may be used to collimate the light for reducing the energy lost due to light divergence
Data Source
AI summary
A semiconductor device is provided. The semiconductor device includes a substrate and a light-collimating layer. The substrate has a plurality of pixels. The light-collimating layer is disposed on the substrate, and the light-collimating layer includes a transparent material layer, a first light-shielding layer, a second light-shielding layer and a plurality of transparent pillars. The transparent material layer covers the pixels. The first light-shielding layer is disposed on the substrate and the first light-shielding layer has a plurality of holes corresponding to the pixels. The second light-shielding layer is disposed on the first light-shielding layer. The transparent pillars are disposed in the second light-shielding layer.