Microlens Uniformity in Solid-State Imaging Devices
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Solution Overview
Problem
In solid-state imaging devices, the non-uniform formation of oxide films between lens layers leads to sensitivity unevenness across pixels, affecting the optimization of microlens curvature and refractive index.
Innovation Solution
A solid-state imaging device with a pixel array unit featuring microlenses formed by laminating multiple lens layers, where a film with a uniform thickness is intentionally formed between the lens layers, specifically an oxide film with a refractive index lower than the lens layers, to prevent sensitivity unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If oxide film is formed between lens layers by microlens formation process, then lens layers are laminated, but oxide film is not formed uniformly leading to sensitivity unevenness
Solution Approach 1:
A flatting process is performed before the microlens formation process to create a flat surface on the color filter layer. This preliminary action prevents non-uniform oxide film formation during subsequent microlens fabrication, ensuring uniform sensitivity across all pixels by eliminating surface irregularities that would cause uneven oxide deposition
Solution Approach 2:
The flatting process is separated as a distinct preliminary step before microlens formation. By extracting the surface flattening operation from the microlens formation process itself, the patent ensures that the oxide film formation occurs on a uniformly flat surface, preventing sensitivity unevenness
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 configuration ensures uniform light concentration and prevents sensitivity unevenness, allowing the light-concentrating point to align with the photoelectric conversion unit even in the front focus state, enhancing image quality.
Implementation Method 1
a film having a uniform film thickness is formed between lens layers... The film may have a refractive index lower than a refractive index of the lens layer
Data Source
AI summary
The present technology relates to a solid-state imaging device, a production method, and an electronic apparatus that can prevent sensitivity unevenness from generating. The solid-state imaging device includes a pixel array unit having a plurality of pixels, a microlens formed by laminating a plurality of lens layers for the every pixel, and a film formed between the lens layers with a uniform film thickness having a refractive index lower than a refractive index of the lens layer. The present technology is applicable to an amplification type solid-state imaging device such as a surface irradiation type or rear irradiation type CMOS image sensor, and a charge transfer type solid-state imaging device such as a CCD image sensor.