Stacked Lens Alignment via Segmented Ring Marks
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Solution Overview
Problem
In the wafer-level lens process, achieving high accuracy in shape and position alignment of lenses during the stacking of substrates with lenses is challenging due to limitations in existing alignment methods, particularly those relying on patterns larger than the lens size, which result in errors and inaccuracies.
Innovation Solution
A stacked lens structure and manufacturing method that utilize alignment marks on substrates with lenses, where a first substrate with a first alignment mark and a second substrate with a second alignment mark are directly bonded, allowing for precise alignment and bonding based on these marks, thereby enhancing the accuracy of lens alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If alignment is performed using a step on the outer circumference of the lens (larger than lens size), then alignment is easier to implement, but alignment accuracy deteriorates due to large pattern errors
Solution Approach 1:
The alignment mark is segmented into a ring shape with multiple discontinuous segments around the lens. This segmentation allows the alignment mark to be smaller than the lens while maintaining alignment functionality, resolving the contradiction between ease of implementation and alignment accuracy by enabling precise alignment without requiring large outer circumference steps.
Solution Approach 2:
The alignment approach transitions from using the outer circumference of the lens (radial dimension) to using a ring-shaped alignment mark in the annular region surrounding the lens (concentric dimension). This dimensional change enables alignment accuracy to be maintained or improved while reducing the overall size requirement, as the alignment mark can be positioned independently from the lens outer edge.
2Reliability
If substrates are stacked with lenses requiring high accuracy alignment, then optical performance is improved, but manufacturing complexity increases due to alignment difficulties
Solution Approach 1:
The ring-shaped alignment mark is formed simultaneously with the lens in the same molding process, rather than requiring separate alignment mark formation and stacking steps. This preliminary action integrates the alignment function into the lens manufacturing itself, reducing manufacturing process complexity while maintaining high alignment accuracy for optimal optical performance.
Solution Approach 2:
The lens structure itself provides the alignment function through the integrated ring-shaped alignment mark, eliminating the need for separate alignment mechanisms or complex external alignment procedures. This self-service approach simplifies the manufacturing process while ensuring high alignment accuracy between stacked substrates.
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
Substrates with lenses having lenses disposed therein are aligned with high accuracy. A stacked lens structure has a configuration in which substrates with lenses having a lens disposed on an inner side of a through-hole formed in the substrate are direct-bonded and stacked based on an alignment mark. The alignment mark is formed simultaneously with the through-hole. The present technique can be applied to a camera module or the like in which a stacked lens structure in which at least three substrates with lenses including first to third substrates with lenses which are substrates with lenses in which a through-hole is formed in the substrate and a lens is formed on an inner side of the through-hole is integrated with a light receiving element, for example.