Opto-Electric Hybrid Board Alignment Mark Placement
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Solution Overview
Problem
The existing opto-electric hybrid board production methods face challenges in accurately positioning alignment marks due to the colored polyimide insulation layer, which hinders the visibility of alignment marks necessary for precise outline processing, leading to potential optical loss and connection issues.
Innovation Solution
The alignment mark is positioned on the front surface of the opto-electric hybrid board, made of the same material as the electric wiring, allowing for direct visibility and accurate positioning, enabling precise outline processing even with a colored polyimide insulation layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If alignment marks are formed on the back side of the insulation layer, then the manufacturing process is simplified, but the visibility of alignment marks deteriorates due to the colored polyimide insulation layer
Solution Approach 1:
Instead of forming alignment marks on the back side of the insulation layer (conventional approach), the patent inverts the approach by forming alignment marks on the front surface of the insulation layer. This is achieved by simultaneously forming the alignment marks together with the electric wiring patterns on the front surface, making them visible against the colored polyimide background without requiring the insulation layer to be transparent.
2Difficulty of detecting and measuring
If alignment marks are formed on the front surface of the insulation layer, then the visibility of alignment marks is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent merges the formation of alignment marks with the formation of electric wiring patterns. Both are simultaneously formed on the front surface of the insulation layer using the same photolithography and plating processes. This integration eliminates the need for separate alignment mark formation steps, thereby maintaining manufacturing simplicity while achieving excellent visibility of alignment marks.
3Reliability
If the insulation layer is made of colored polyimide, then the insulation properties are improved, but the visibility of alignment marks on the back side deteriorates
Solution Approach 1:
The patent applies local quality by forming alignment marks only in specific locations where they are needed for outline processing, rather than requiring the entire insulation layer to be transparent. The alignment marks are created as localized metallic patterns on the front surface, allowing the bulk of the insulation layer to maintain its colored polyimide composition with excellent insulation properties.
Data Source
AI summary
An opto-electric hybrid board is provided, which includes an electric circuit board including an electric wiring provided on a front surface of an insulation layer, an optical waveguide provided on a back side of the electric circuit board, and an outline processing alignment mark positioned adjacent to an outline processing portion on the front surface of the insulation layer on the same basis as the electric wiring, and has an outline formed by performing an outline processing operation with reference to the outline processing alignment mark. The opto-electric hybrid board has an accurate outline and, therefore, can be attached to other component without an engagement failure or a connection failure.