Pixel Color Filter Wall Structure for Low-Crosstalk Imaging
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Solution Overview
Problem
In image sensors, increasing the width of voids to reduce crosstalk between pixels deteriorates light collection properties due to the need for thicker films, which increases the distance between on-chip lenses and photoelectric conversion elements.
Innovation Solution
An imaging device with a wall-shaped structure portion defined by a first wall portion, separating color filters, and a closing film that reduces crosstalk without increasing film thickness, allowing for efficient light collection by maintaining the distance between photoelectric conversion units and on-chip lenses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the width of void is increased to reduce crosstalk between pixels, then crosstalk reduction is improved, but the distance between on-chip lenses and photoelectric conversion elements increases causing deterioration of light collection property
Solution Approach 1:
The invention transitions from a single-layer void structure to a multi-layer structure with wall-shaped structure portions extending vertically between color filters. This vertical dimension addition allows for effective crosstalk reduction through lateral separation while maintaining controlled vertical distances for optimal light collection. The wall-shaped structures create spatial separation in multiple dimensions simultaneously.
Solution Approach 2:
The void space between pixels is segmented into multiple regions by introducing wall-shaped structure portions that extend vertically. Instead of a single continuous void, the space is divided into multiple compartments separated by these wall structures, allowing independent optimization of each region's dimensions for both crosstalk reduction and light collection efficiency.
2Object-affected harmful factors
If a thicker film is used to close the trench, then crosstalk reduction is improved, but the distance between on-chip lenses and photoelectric conversion elements increases
Solution Approach 1:
The solution moves from increasing film thickness in the vertical direction to creating lateral separation through wall-shaped structures. The wall-shaped structure portions extend vertically to provide separation without requiring increased film thickness, thereby maintaining the vertical distance between on-chip lenses and photoelectric conversion elements at optimal levels.
Solution Approach 2:
Instead of uniformly increasing film thickness across the entire structure, the invention applies wall-shaped structure portions selectively in the regions between color filters where crosstalk occurs. This localized approach provides crosstalk reduction precisely where needed without affecting the overall vertical dimensions of the pixel structure.
Data Source
AI summary
More improvement of sensitivity is achieved by reducing crosstalk between pixels without deteriorating a light collection property. Provided is an imaging device including multiple pixels each including a photoelectric conversion unit and planarly arranged in a matrix shape, a color filter provided on the photoelectric conversion unit for each of the pixels, and a wall-shaped structure portion that is formed between the adjoining color filters with an external shape of the wall-shaped structure portion defined by a first wall portion and is configured to separate the color filters from each other.