Microlens Protective Film for Solid-State Image Sensor Moisture Resistance
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Solution Overview
Problem
Conventional solid-state image capturing apparatuses with microlenses have a hollow area above the element, allowing moisture infiltration and leading to corrosion and reliability issues, despite attempts to prevent moisture ingress through glass seals and reflection prevention films.
Innovation Solution
A solid-state image capturing apparatus with a protective film covering exposed portions of the insulation substrate, microlens, and wire, using a refractive index intermediate between the microlens and air to prevent moisture ingress and maintain high reliability, employing a multilayer structure of SiO2, SiN, or SiON films formed by plasma CVD.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a hollow space is provided above the microlens in conventional solid-state image capturing apparatuses, then light focusing performance is improved, but moisture infiltration occurs leading to corrosion and reliability degradation
Solution Approach 1:
A protective film is formed over the microlens and exposed surfaces within the sealing package. This thin film structure maintains the hollow space configuration for light focusing while providing moisture barrier protection, preventing corrosion of internal components.
Solution Approach 2:
The protective film creates a protected environment within the sealing package by blocking moisture ingress. This effectively isolates the internal components (microlens, wires, insulation substrate) from the harmful external environment, maintaining a dry and stable atmosphere.
2Ease of manufacture
If exposed surfaces are left uncovered in the hollow space, then manufacturing simplicity is maintained, but corrosion occurs due to moisture infiltration
Solution Approach 1:
A protective film is formed over the microlens and exposed surfaces within the sealing package. This thin film structure maintains the hollow space configuration for light focusing while providing moisture barrier protection, preventing corrosion of internal components.
Solution Approach 2:
The protective film formation process automatically covers all exposed surfaces within the sealing package through a conformal deposition process. The manufacturing process itself provides the protective function without requiring additional manual intervention or complex assembly steps.
3Reliability
If a protective film is formed over all exposed surfaces, then moisture resistance is improved, but manufacturing complexity increases
Solution Approach 1:
A protective film is formed over the microlens and exposed surfaces within the sealing package using standard thin film deposition techniques, integrating the protection function into the existing manufacturing flow.
Solution Approach 2:
The protective film formation process automatically covers all exposed surfaces within the sealing package through a conformal deposition process. The manufacturing process itself provides the protective function without requiring additional manual intervention or complex assembly steps.
4Illumination intensity
If reflection prevention films are used, then light reflection is reduced, but moisture infiltration paths remain open
Solution Approach 1:
A protective film is formed over the microlens and exposed surfaces within the sealing package. This thin film structure maintains the hollow space configuration for light focusing while providing moisture barrier protection, preventing corrosion of internal components.
Solution Approach 2:
The protective film can be implemented as a composite structure combining materials with different properties - one layer optimized for anti-reflection optical characteristics and another layer providing superior moisture barrier performance, achieving both functions simultaneously.
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
The protective film effectively prevents corrosion and maintains high reliability by covering all exposed surfaces within the sealing package, reducing moisture ingress and reflection while ensuring effective light focusing.
Implementation Method 1
portions of the insulation film, the solid-state image capturing element and the wire, which are exposed in the hollow space, are all covered with a protective film
Implementation Method 2
employing a multilayer structure of SiO2, SiN, or SiON films formed by plasma CVD
Implementation Method 3
A solid-state image capturing apparatus with a protective film covering exposed portions of the insulation substrate, microlens, and wire, using a refractive index intermediate between the microlens and air
Data Source
AI summary
A solid-state image capturing apparatus includes: an insulation substrate including an external lead terminal; a solid-state image capturing element fixed on the insulation substrate and including a microlens; and a transparent glass member positioned above the insulation substrate for sealing the solid-state image capturing element fixed on the insulation substrate, and an electrode of the solid-state image capturing element and the external lead terminal of the insulation substrate being connected by a wire, wherein the transparent glass member is positioned in such a manner that a hollow space is formed between a microlens of the solid-state image capturing element and the transparent glass member, and wherein portions of the insulation film, the solid-state image capturing element and the wire, which are exposed in the hollow space, are all covered with a protective film.