Stacked Lens Substrate Groove Design for Dicing Chipping Reduction
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Solution Overview
Problem
The challenge in dicing wafer substrates after stacking results in chipping that can lead to breakage of the stacked lens structure, making it difficult to achieve multi-layer stacking in mass production.
Innovation Solution
A stacked lens structure is created by forming a through-hole in a substrate, placing a lens within the hole, and adding a groove adjacent to the hole, allowing for direct joining of substrates using covalent bonds formed between oxide or nitride layers, which suppresses deformation caused by curing contraction or thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wafer substrates are stacked and then diced, then multi-layer lens structure is achieved, but chipping occurs causing breakage of the stacked lens structure
Solution Approach 1:
The substrate is divided into multiple stacked layers, each containing through-holes for lenses. The grooves are segmented features that run through the substrate thickness, creating independent channels that prevent chip propagation during dicing while maintaining the stacked structure.
Solution Approach 2:
Grooves are formed in advance before dicing to act as stress relief channels. These pre-formed grooves cushion the mechanical stress during the dicing process, preventing chips from reaching and breaking the through-holes containing lenses.
2Manufacturing precision
If strict requirements for shape accuracy and position accuracy are imposed, then lens manufacturing precision is improved, but process difficulty increases making mass production unfeasible
Solution Approach 1:
Through-holes are formed in the substrate before lens installation. This preliminary action allows for precise positioning and alignment of lenses in subsequent steps, achieving high manufacturing precision while simplifying the overall process for mass production.
Solution Approach 2:
The through-hole structure acts as an intermediary element that facilitates both precise lens positioning and ease of assembly. It serves as a pre-formed cavity that guides lens placement while enabling standardized manufacturing processes.
3Ease of manufacture
If adhesive is used to join substrates, then stacking is enabled, but deformation occurs due to curing contraction or thermal expansion
Solution Approach 1:
The adhesive layer is extracted and replaced with direct substrate-to-substrate bonding through oxide or nitride layers. This eliminates the harmful deformation effects of adhesive curing contraction and thermal expansion while maintaining the substrate stacking function.
Solution Approach 2:
The bonding mechanism changes from chemical adhesive bonding to direct crystalline bonding through oxide or nitride layers. This parameter change in the bonding method eliminates thermal and dimensional instability while maintaining structural integrity of the stacked substrate.
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 method effectively reduces chipping and breakage during dicing, enabling the successful stacking of multiple layers and improving the reliability and accuracy of the lens structure.
Implementation Method 1
direct joining of substrates using covalent bonds formed between oxide or nitride layers
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
Influence of chipping in case of dicing a plurality of stacked substrates is reduced. Provided is a semiconductor device where a substrate, in which a groove surrounding a pattern configured with a predetermined circuit or part is formed, is stacked. The present technology can be applied to, for example, a stacked lens structure where through-holes are formed in each substrate and lenses are disposed in inner sides of the through-holes, a camera module where a stacked lens structure and a light-receiving device are incorporated, a solid-state imaging device where a pixel substrate and a control substrate are stacked, and the like.