Flip Chip Mounting Camera System with Rotatable Mirror
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Solution Overview
Problem
The flip chip mounting process requires high precision in placing semiconductor chips with bumps onto substrates, necessitating complex camera systems for accurate positioning, which can be cumbersome and inefficient.
Innovation Solution
A single camera with an optical switch, utilizing a rotatable mirror or color filters, alternates its field of view to determine the position of both the semiconductor chip on the wafer and the flip chip on the bonding head, simplifying the camera system without compromising precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single camera is used to determine both wafer chip position and flip chip position, then device complexity is reduced, but measurement precision may be compromised due to the need to switch between different fields of view
Solution Approach 1:
The patent implements a dynamic optical switching system where a first optical switch alternates the camera's field of view between the wafer chip position and the flip chip position based on the flipping apparatus's rotational position. This dynamic switching allows a single camera to effectively perform multiple measurement functions with precision comparable to multiple fixed cameras, resolving the contradiction between device complexity and measurement precision.
2Measurement precision
If multiple cameras are used to monitor both wafer and substrate positions, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent makes the single camera universal by enabling it to perform multiple functions: determining wafer chip position, determining flip chip position, and monitoring substrate position through the optical switching system. This multi-functionality eliminates the need for multiple dedicated cameras while maintaining comprehensive position determination capability, thus improving precision without proportionally increasing complexity.
Solution Approach 2:
The optical switch acts as an intermediary device that directs light from different object positions (wafer chip, flip chip) to the single camera sensor. This intermediary mechanism allows the camera to sequentially observe multiple positions with high precision without requiring simultaneous multi-camera setups, resolving the contradiction between precision and complexity.
3Reliability
If two cameras are used to take pictures of the chip before and after flipping, then reliability of position detection is improved, but device complexity and cost increase
Solution Approach 1:
The patent implements periodic action by having the single camera alternately capture images of the chip at different stages (before flipping and after flipping) through the optical switching system. The camera periodically switches between monitoring the wafer chip position and the flip chip position, achieving reliable position detection at both stages without the need for two permanently installed cameras, thus improving reliability while controlling complexity.
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 configuration reduces the complexity of camera systems, ensuring precise positioning of flip chips on substrates with improved operational efficiency and reduced mechanical alignment requirements.
Implementation Method 1
A single camera with an optical switch, utilizing a rotatable mirror or color filters, alternates its field of view
Data Source
AI summary
An apparatus for mounting semiconductor chips as flip chips on a substrate includes a chip supply, a pick-and-place system with a bonding head having a chip gripper, a flipping apparatus operable to rotate the chip from a first position to a second (flipped) position through an angle with a gripper and two cameras. The first camera determines a position of the chip before the flipping apparatus receives the chip and also determines a position of the flipped chip received by the chip gripper of the bonding head once the flipping apparatus has transferred the chip to it. The apparatus also comprises an optical switch, e.g., a rotatable mirror located in the field of view of the first camera. The mirror operates to rotate with the gripper of the flipping apparatus but at half the angle.