Solid-State Image Sensor Groove Structure for Film Thickness Control
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Solution Overview
Problem
Existing solid-state imaging devices face challenges in improving reliability and reducing manufacturing costs, particularly when using silicon on insulator (SOI) substrates, which increase costs and do not adequately enhance device characteristics.
Innovation Solution
A solid-state imaging device design that includes a groove on the semiconductor substrate with oblique side walls, embedded with insulating material, allowing for precise control of film thickness and reducing manufacturing costs by using a normal semiconductor substrate instead of SOI, and a manufacturing method involving the formation and exposure of such grooves to enhance device reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a silicon on insulator (SOI) substrate is used to prevent variations in film thickness, then manufacturing precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent divides the semiconductor substrate into multiple regions with different depths by forming grooves at specific locations. This segmentation allows selective thinning of the substrate in certain areas while maintaining appropriate thickness in other areas, achieving precise film thickness control without requiring an expensive SOI substrate.
Solution Approach 2:
The patent applies local quality by creating regions with different substrate thicknesses through groove formation. The grooves are formed in specific regions (such as peripheral regions or scribe regions) to achieve local thinning, allowing the substrate to have optimal thickness in different areas for different functions, thereby improving manufacturing precision without increasing overall cost.
2Ease of manufacture
If existing low-cost manufacturing methods are used without SOI substrate, then manufacturing cost is reduced, but device reliability does not improve sufficiently
Solution Approach 1:
The patent performs preliminary action by forming grooves in the semiconductor substrate before bonding with the insulating layer. This preliminary groove formation enables subsequent precise thinning operations and ensures proper film thickness control, thereby improving device reliability while maintaining cost-effectiveness by avoiding SOI substrates.
Solution Approach 2:
The patent introduces an insulating layer as an intermediary between the semiconductor substrate and the bonding layer. This insulating layer, combined with the groove structure, mediates the bonding process to achieve reliable device performance without requiring expensive SOI substrates, thus improving reliability while keeping manufacturing costs low.
Data Source
AI summary
Provided is a solid-state imaging device capable of further improving reliability of a solid-state imaging device and further reducing manufacturing cost. Provided is a solid-state imaging device including a second semiconductor substrate provided with a photoelectric conversion unit and a second element, a second insulating layer, a first semiconductor substrate provided with a first element, and a first insulating layer arranged in this order from a light incident side, and including a groove formed on the first semiconductor substrate, in which the groove has a first side wall and a second side wall, and a part of at least one side wall of the first side wall or the second side wall extends in an oblique direction with respect to a surface of the first semiconductor substrate on the light incident side.