Image Sensor Light Guiding Structure for Crosstalk Reduction
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Solution Overview
Problem
The existing image sensor devices face challenges in achieving improved performance and reliability due to issues such as stress and charge concentration caused by non-planar dielectric structures, which can lead to reduced performance and increased crosstalk between neighboring pixel regions.
Innovation Solution
The implementation of a light guiding structure with a dielectric structure having a substantially planar top surface, which is achieved through processes like chemical mechanical polishing, and the formation of a light blocking grid surrounding filters to prevent stress and charge concentration, thereby enhancing the performance and reliability of the image sensor device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a non-planar dielectric structure is used, then the manufacturing process is simpler, but stress and charge concentration occur leading to reduced performance and increased crosstalk
Solution Approach 1:
The patent applies preliminary action by performing chemical mechanical polishing (CMP) on the dielectric structure before subsequent processing steps. This pre-planarization ensures that the dielectric surface is substantially planar before forming additional layers or structures, preventing stress and charge concentration issues that would otherwise occur with non-planar surfaces. The CMP process is performed in advance to establish a stable foundation for subsequent manufacturing steps.
2Ease of manufacture
If a non-planar dielectric structure is used, then the manufacturing process is simpler, but crosstalk between neighboring pixel regions increases
Solution Approach 1:
The patent applies preliminary action by performing chemical mechanical polishing (CMP) on the dielectric structure before subsequent processing steps. This pre-planarization ensures that the dielectric surface is substantially planar before forming additional layers or structures, preventing stress and charge concentration issues that would otherwise occur with non-planar surfaces. The CMP process is performed in advance to establish a stable foundation for subsequent manufacturing steps.
3Productivity
If geometric size is reduced to increase functional density, then more circuits fit per chip area, but stress and charge concentration issues worsen
Solution Approach 1:
The patent applies local quality by making the dielectric structure planar specifically in the regions where pixel circuits are formed, while allowing other regions to have different characteristics. The chemical mechanical polishing process selectively planarizes the dielectric surface over the array region containing the pixel circuits, ensuring that the critical areas have uniform stress distribution and charge characteristics, while maintaining manufacturing efficiency elsewhere on the chip.
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 guiding structure significantly reduces crosstalk between neighboring pixel regions and improves the overall performance and reliability of the image sensor device by eliminating stress and charge concentration, leading to better image capture capabilities.
Implementation Method 1
achieved through processes such as chemical mechanical polishing
Data Source
AI summary
An image sensor device and a manufacturing method for forming an image sensor device are provided. The image sensor device includes a semiconductor substrate having an array region and a periphery region. The image sensor device also includes a light sensing region in the array region of the semiconductor substrate. The image sensor device further includes a dielectric structure over the array region and the periphery region, and the dielectric structure has a substantially planar top surface. In addition, the image sensor device includes a recess in the dielectric structure and substantially aligned with the light sensing region. The image sensor device also includes a filter in the recess and a light blocking grid in the dielectric structure and surrounding a portion of the filter.