Forward Tapered Insulation Structure for Solid State Imaging
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Solution Overview
Problem
Existing solid state imaging apparatuses face issues with chipping during dicing and flare components due to metal guard rings and inverse tapered shapes, which affect reliability and imaging quality.
Innovation Solution
A solid state imaging apparatus with an insulation structure formed of a non-metallic, forward tapered shape penetrating through a silicon layer at the light receiving surface, reducing the risk of chipping and flare by using insulation materials like silicon compounds and copolymerization-based resins, and trenching methods to connect wiring layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal material is used as burying material of guard ring, then reliability is improved, but metal diffusion occurs when crack is generated by bonding damage
Solution Approach 1:
The patent replaces the metal guard ring with an insulation structure made of non-metallic material (such as insulation film or insulation substance). This substitution eliminates the harmful metal diffusion effect while maintaining the protective function of the guard ring. The insulation structure serves as a disposable protective element that prevents chipping during dicing without risking metal contamination.
2Reliability
If guard ring has inverse tapered shape where diameter is gradually increased as it is away from light incident surface side, then protection function is improved, but incident light is reflected by guard ring causing flare to worsen
Solution Approach 1:
The patent inverts the traditional guard ring shape from an inverse tapered shape (wider at the bottom) to a forward tapered shape (wider at the top). This shape inversion allows the guard ring to maintain its protective function against chipping during dicing while simultaneously reducing light reflection and flare. The forward tapered shape directs light away from the photoelectric conversion element, eliminating the harmful flare effect.
3Object-generated harmful factors
If insulation structure has forward tapered shape where top diameter is greater than bottom diameter, then flare component is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies particular parameter ranges for the forward tapered insulation structure, including the depth (0.5-5.0 μm) and shape characteristics. By defining these parameters within specific ranges, the patent optimizes the balance between reducing flare and maintaining manufacturability. The insulation structure's depth and taper ratio are controlled to achieve effective flare reduction while remaining compatible with standard semiconductor manufacturing processes.
Data Source
AI summary
A solid state imaging apparatus includes an insulation structure formed of an insulation substance penetrating through at least a silicon layer at a light receiving surface side, the insulation structure having a forward tapered shape where a top diameter at an upper portion of the light receiving surface side of the silicon layer is greater than a bottom diameter at a bottom portion of the silicon layer. Also, there are provided a method of producing the solid state imaging apparatus and an electronic device including the solid state imaging apparatus.