Shielding Layer for Light Pipe Structure in Semiconductor Device
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Solution Overview
Problem
CMOS type image sensors experience increased noise and decreased image resolution due to light scattering from areas outside the light pipe structure, leading to cross-talk phenomena.
Innovation Solution
A semiconductor device with a shielding layer surrounding the light pipe structure to block scattered light and a shielding layer surrounding the pad opening to prevent delamination during heat treatment processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light pipe structure is formed on a photo sensor to increase light sensitivity, then light sensitivity is improved, but scattered light from areas outside the light pipe structure is transmitted to the photo sensor causing cross-talk phenomenon and decreasing image resolution
Solution Approach 1:
A shielding layer is introduced as an intermediary component between the light pipe structure and the surrounding areas. This shielding layer selectively blocks scattered light from reaching the photo sensor while allowing the light pipe to transmit desired light, thereby resolving the cross-talk issue without compromising light sensitivity
Solution Approach 2:
The device structure is segmented into distinct functional zones: a light pipe structure for light transmission, a shielding layer for light blocking, and a photo sensor for light detection. This segmentation allows each component to perform its specific function independently, preventing scattered light from causing cross-talk while maintaining effective light collection
2Measurement precision
If a shielding layer is added to surround the light pipe structure to block scattered light, then image resolution is improved, but device complexity increases
Solution Approach 1:
The shielding layer serves multiple functions simultaneously: it blocks scattered light to prevent cross-talk, defines the optical boundary of the light pipe structure, and can be integrated with existing manufacturing processes. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity
3Reliability
If a shielding layer surrounds the pad opening to prevent delamination during heat treatment, then reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The shielding layer is formed around the pad opening before the protection layer is deposited and before heat treatment processes occur. This preliminary action ensures that when heat treatment is later applied, the shielding layer is already in place to prevent delamination, avoiding the need for complex post-processing steps or specialized manufacturing techniques
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 shielding layer effectively mitigates cross-talk noise, improving image resolution and preventing protection layer delamination, thereby enhancing the performance of CMOS type image sensors.
Implementation Method 1
the shielding layer surrounds the light pipe structure for shielding the light above an area outside the light pipe structure (i.e., the scattered light)
Data Source
AI summary
A semiconductor device including a substrate, at least one sensor, a dielectric layer, at least one light pipe structure, at least one pad, a shielding layer, and a protection layer is provided. The sensor is located in the substrate of a first region. The dielectric layer is located on the substrate. The light pipe structure is located in the dielectric layer of the first region. The light pipe structure corresponds to the sensor. The pad is located in the dielectric layer of a second region. The shielding layer is located on the dielectric layer, wherein the light pipe structure is surrounded by the shielding layer. The protection layer is located on the shielding layer. At least one pad opening is disposed in the dielectric layer, the shielding layer, and the protection layer above the pad. The pad opening exposes a top surface of the corresponding pad.