Solid-State Image Sensor Light-Guide Formation via Low-Temperature Deposition
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Solution Overview
Problem
The manufacturing of solid-state image sensors is hindered by stress and potential separation between silicon oxide and silicon carbide layers due to their differing thermal expansion coefficients, which affects the quality of the sensor.
Innovation Solution
A method is introduced where the silicon carbide layers are formed at a lower temperature than the silicon oxide layers, and a transparent member with a higher refractive index is used to guide light, reducing stress and improving sensor quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If light-guide portions are formed by depositing transparent member at high temperature, then the transparent member can be properly formed, but stress and separation occur between silicon oxide and silicon carbide layers due to thermal expansion coefficient difference
Solution Approach 1:
The patent changes the temperature parameter from high temperature to low temperature (specifically room temperature or lower) when forming the transparent member. This parameter change prevents thermal stress and separation between silicon oxide and silicon carbide layers by avoiding temperature-induced expansion differences, while still achieving proper formation of the light-guide portion through controlled deposition at lower temperature.
2Ease of manufacture
If transparent member is formed at high temperature by plasma CVD, then light-guide portion can be formed effectively, but thermal stress causes layer separation reducing sensor quality
Solution Approach 1:
The patent changes the deposition temperature parameter from high temperature plasma CVD to low temperature process (room temperature or lower). This maintains the ease of manufacturing light-guide portions through effective material deposition while eliminating thermal stress that causes layer separation, thereby improving overall sensor reliability and quality.
Solution Approach 2:
The patent replaces the thermal field (high temperature plasma CVD) with a low-temperature deposition process. This substitution eliminates the thermal stress mechanism that causes layer separation, while still achieving the desired light-guide portion formation through controlled material deposition at lower temperatures.
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 prevents separation between the layers and enhances the quality of the solid-state image sensor by controlling the temperature during the manufacturing process, specifically by forming light-guide portions at a temperature lower than that used for silicon carbide layers, thereby maintaining structural integrity and performance.
Implementation Method 1
Each light-guide portion guides light which has passed through an optical element such as a microlens to the photoelectric conversion portion
Implementation Method 2
Each light-guide portion guides light which has passed through an optical element such as a microlens to the photoelectric conversion portion
Implementation Method 3
The transparent member is formed at a relatively high temperature by a deposition method such as plasma CVD
Implementation Method 4
a difference in a thermal expansion coefficient is large between silicon oxide of the interlayer insulating layers and silicon carbide of the anti-diffusion layers. This causes a reduction in quality of the solid-state image sensor
Data Source
AI summary
A method for manufacturing a solid-state image sensor, the method comprising preparing a substrate including a photoelectric conversion portion, forming, on the substrate, a structure which includes a first member made of a material containing silicon oxide and a second member arranged on the first member and made of a material containing silicon carbide, forming an opening in a position above the photoelectric conversion portion in the structure by removing a part of the first and the second members, and forming a transparent member in the opening, wherein the second member is formed at a first temperature and the transparent member is formed at a second temperature lower than the first temperature.