Back Surface Radiation Image Sensor Wiring Density

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Back surface radiation type image sensors face challenges in maintaining equalized wiring density in the uppermost layer of the wiring layer, leading to light reflection issues and brightness irregularities due to dummy wiring lines, which affect image quality.

Innovation Solution

Arranging dummy wiring lines in pixel regions that receive light of wavelengths shorter than a predetermined wavelength, such as blue and green light, to adjust the wiring density while minimizing light reflection and maintaining image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If dummy wiring lines are added to equalize wiring density in the uppermost layer, then wiring density equalization is improved, but light reflection increases causing brightness irregularities

Engineering Contradiction:

Improvewiring density equalizationVSAvoidlight reflection from dummy wiring lines

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by making different parts of the dummy wiring lines have different properties: some portions are transparent to specific wavelength ranges of light, while other portions are opaque. This allows the dummy wiring lines to maintain wiring density equalization while minimizing light reflection in regions where it would cause brightness irregularities.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the optical parameters of the dummy wiring lines by assigning different transparency characteristics to different portions. Specifically, portions above photoelectric conversion units for certain wavelengths are made transparent to those wavelengths, while other portions remain opaque, thereby controlling light reflection based on wavelength-specific requirements.

Inventive Principle:

Principle #35Parameter changes

2Illumination intensity

If the substrate is reversed and polished for back surface radiation type structure, then light reception brightness is improved, but wiring density equalization in the uppermost layer becomes difficult

Engineering Contradiction:

Improvelight reception brightnessVSAvoidwiring density equalization

Core Design Contradiction:

Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent segments the dummy wiring lines into multiple portions with different characteristics. By dividing the dummy wiring lines into wavelength-specific transparent and opaque portions, the patent achieves both wiring density equalization and compatibility with the back surface radiation type structure's light reception requirements.

Inventive Principle:

Principle #1Segmentation

3Device complexity

If wiring lines are made small in the pixel region, then device complexity is reduced, but wiring density becomes non-uniform

Engineering Contradiction:

Improvewiring line sizeVSAvoidwiring density uniformity

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by creating portions of dummy wiring lines with different transparency properties in different locations. This allows the wiring structure to maintain simplicity with smaller wiring lines while achieving uniform wiring density through the strategic placement of transparent and opaque dummy wiring portions.

Inventive Principle:

Principle #3Local quality

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 approach reduces the influence of light reflection from dummy wiring lines, achieving equalized wiring density and improved image quality by strategically placing dummy wiring lines in regions receiving shorter wavelengths, thereby minimizing brightness irregularities and enhancing image clarity.

Implementation Method 1

back surface radiation type image sensor... light may be received from the back surface side

Methodology Applied

Scientific EffectPhotoelectric conversion: Photoelectric Effect

Implementation Method 2

the color filter and the on-chip lens are formed directly on the imaging element

Methodology Applied

Scientific EffectOptical filtering: Filter (optical)

Implementation Method 3

the on-chip lens... are formed directly on the imaging element

Methodology Applied

Scientific EffectLight focusing: Lens

Implementation Method 4

the substrate of the back surface side is polished to a predetermined thickness

Methodology Applied

Scientific EffectChemical mechanical polishing:

Data Source

PatentEP3028306B1Back surface radiation type image sensor, imaging device, and electronic apparatus

Publication Date: 2020.04.29 SONY GROUP CORP

Figure 1A~1C
Figure 2
Figure 3

AI summary

A device including a substrate and an imaging element layer having a plurality of imaging elements is provided, where the imaging element layer is located between the substrate and a wiring layer having a plurality of wiring lines (41), and wiring lines of the wiring layer are arranged in pixel regions (Z) configured to receive light having a wavelength less than a predetermined wavelength (B, G). Accordingly, by more uniformly distributing the wiring layer throughout, it is possible to reduce an unevenness that occurs at a polishing film. Moreover, because wiring lines are not disposed in pixel regions (Z) configured to receive light having a wavelength greater than the predetermined wavelength (R), irregularities may be reduced.