Titanium Black Dispersion for Wafer Level Lens Light Shielding
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Solution Overview
Problem
Conventional light-shielding compositions for wafer level lenses leave residues near the lenses, causing light transmittance issues, and existing titanium black-based compositions fail to adequately shield infrared light effectively.
Innovation Solution
A titanium black dispersion with particles of 30 nm or less and a specific Si/Ti ratio is used in a photosensitive resin composition for wafer level lenses, which includes a photopolymerizable compound and photopolymerization initiator, to form a light-shielding film that reduces residues and enhances infrared light shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional light-shielding compositions are used, then light-shielding function is provided, but residues remain near lenses causing light transmittance issues
Solution Approach 1:
The patent changes the particle size parameter of titanium black from conventional larger sizes to specifically 30 nm or less, and controls the Si/Ti ratio to 0.05 or higher. These parameter changes enable the light-shielding film to reduce residues while maintaining light-shielding function, resolving the contradiction between providing light-shielding and preventing residue formation that affects light transmittance.
2Object-affected harmful factors
If conventional titanium black-based compositions are used, then light-shielding is provided, but infrared light shielding is insufficient
Solution Approach 1:
The patent optimizes the particle size parameter of titanium black to 30 nm or less and controls the Si/Ti ratio to 0.05 or higher, which enhances the material's ability to shield infrared light. This resolves the contradiction by improving infrared light shielding performance while effectively reducing noise in solid-state image pickup devices.
3Object-affected harmful factors
If light-shielding film is formed to block infrared light, then infrared shielding is improved, but residues may affect light transmittance
Solution Approach 1:
The patent simultaneously optimizes two parameters: titanium black particle size (30 nm or less) and Si/Ti ratio (0.05 or higher). This combined parameter control enables the light-shielding film to effectively block infrared light while minimizing residue formation near lenses, thus maintaining light transmittance and resolving the contradiction between infrared shielding and residue reduction.
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 solution effectively decreases residues and improves light transmittance near the light-shielding film, while providing excellent infrared light shielding, reducing noise in solid-state image pickup devices.
Implementation Method 1
a photosensitive resin composition for a wafer level lens including the titanium black dispersion, a photopolymerizable compound, and a photopolymerization initiator
Data Source
AI summary
A titanium black dispersion includes titanium black particles, a dispersant, and an organic solvent. When the titanium black dispersion is for a wafer level lens, 90% or more of dispersed objects that consist of the titanium black particles have particle diameters of 30 nm or less, or dispersed objects including the titanium black particles contains Si atoms and the content ratio of Si atoms to Ti atoms (Si/Ti) in the dispersed objects is 0.05 or higher. When the titanium black dispersion is used for formation of a light-shielding film that is provided on one side of a silicon substrate having an image pickup device section on the other side, and that shields against infrared light, 90% or more of dispersed objects that consist of the titanium black particles have particle diameters of 30 nm or less.