Transparent Chip Mounting Tool for Sub-Micron Face-Down Alignment
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Solution Overview
Problem
Face-down mounting of chip components on substrates faces challenges in achieving high precision due to limitations in alignment accuracy, especially when electrode pitch is small, such as with Cu pillar bumps, leading to insufficient mounting accuracy and increased costs from enhanced machining accuracy and rigidity requirements.
Innovation Solution
A mounting device with a transparent attachment tool, a mounting head, an elevating unit, a substrate stage, a chip position recognition unit, a substrate position recognition unit, and a control unit, which uses recognition marks on both the chip and substrate to align the components with sub-micron accuracy by acquiring and adjusting positions based on relative mark positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an upper and lower two-field camera is used to improve alignment accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
A transparent attachment tool is introduced as an intermediary component that carries recognition marks and can be observed from below through the substrate. This allows the chip position recognition unit to acquire position information of both the chip recognition mark and tool recognition mark simultaneously, enabling accurate alignment without requiring complex upper and lower two-field camera systems.
Solution Approach 2:
Instead of placing recognition marks directly on the chip and substrate surfaces for direct observation, the invention inverts the approach by placing a recognition mark on the transparent attachment tool that holds the chip. This allows the mark to be observed from below through the transparent tool and substrate, simplifying the alignment system.
2Manufacturing precision
If machining accuracy and rigidity of mounting device components are increased to reduce tilt, then manufacturing precision is improved, but device complexity and cost increase
Solution Approach 1:
The invention replaces mechanical alignment methods (relying on machining accuracy and rigidity to minimize tilt) with an optical observation method. By making the attachment tool transparent and placing recognition marks on it, the system can optically detect and correct positional deviations, eliminating the need for high-precision mechanical machining and rigid structures.
3Manufacturing precision
If chip and substrate are brought closer for alignment, then manufacturing precision is improved, but measurement precision deteriorates due to camera focal length and thickness limitations
Solution Approach 1:
The transparent attachment tool serves as a mediator that allows optical observation through multiple layers (tool and substrate) simultaneously. By placing the recognition mark on this transparent intermediary, the system can achieve accurate position measurement even when the chip is brought close to the substrate, overcoming the limitations of camera focal length and component thickness.
Data Source
AI summary
A mounting device mounts a chip component having a chip recognition mark and a substrate having a substrate recognition mark. An attachment tool has transparency and has a tool recognition mark. The attachment tool holds a surface of the chip component opposite to a surface having the chip recognition mark. A chip position recognition unit simultaneously acquires position information of the chip recognition mark and of the tool recognition mark. The substrate position recognition unit acquires position information of the substrate recognition mark and of the tool recognition mark. A control unit moves a substrate stage holding the substrate or the attachment tool in the in-plane direction of the substrate on the basis of information obtained by the chip position recognition unit and by the substrate position recognition unit to perform alignment between the chip component and the substrate.