Transparent Spindle Alignment for Sub-Micron Device Placement
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Solution Overview
Problem
Existing electronic device placement systems lack the ability to achieve sub-micron precision alignment without requiring special features on the substrate, and are prone to inaccuracies due to thermal and friction effects over time.
Innovation Solution
A system and method utilizing a spindle assembly with a transparent spindle body and dual cameras, one facing upward to image the device bottom and one downward to image substrate edges, enabling precise alignment through simultaneous imaging and fine adjustments using piezo stages for sub-micron accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If machine calibration is used to achieve placement accuracy, then placement speed reaches thousands of components per hour, but placement accuracy deteriorates over time due to thermal effects and friction
Solution Approach 1:
The system performs preliminary imaging of the substrate and device features before placement, capturing coordinate information in advance. This allows the vision system to calculate precise placement positions beforehand, compensating for thermal and friction effects that would otherwise degrade accuracy during the placement process.
Solution Approach 2:
The system uses a vision system to image the substrate and device features, then feeds back the actual positions to the controller. The controller calculates compensation values based on the difference between target and actual positions, enabling real-time correction of placement accuracy despite thermal and friction effects.
2Manufacturing precision
If two cameras are used to image substrate marks and device bottom, then placement accuracy reaches single micron level, but substrate surface area is sacrificed for alignment marks
Solution Approach 1:
The system extracts alignment information directly from existing device features (such as the device outline or bonding pads) rather than requiring separate alignment marks on the substrate. This eliminates the need to sacrifice substrate surface area for dedicated alignment marks while maintaining sub-micron placement accuracy.
Solution Approach 2:
The downward-facing camera serves multiple functions: it images the substrate features for alignment, images the device features through the transparent spindle, and enables calculation of both device position and orientation. This multi-functionality eliminates the need for separate alignment mark imaging while maintaining precision.
3Manufacturing precision
If alignment marks are added to substrate, then device alignment to substrate is improved, but placement process complexity increases
Solution Approach 1:
The system merges the alignment function into the existing placement process by using the same downward-facing camera to image both substrate features and device features. The vision system simultaneously processes both images to calculate placement positions, eliminating separate alignment steps and reducing process complexity while maintaining alignment precision.
Solution Approach 2:
The transparent spindle acts as an intermediary that allows the downward-facing camera to image device features through it. This enables the camera to capture both substrate and device features in the same field of view, facilitating direct alignment calculation without requiring additional alignment marks or separate imaging steps.
4Measurement precision
If upward facing camera images device bottom, then device position relative to spindle is determined, but additional calibration steps are required
Solution Approach 1:
The transparent spindle serves as an optical intermediary that allows the downward-facing camera to image device features through it. This eliminates the need for the upward-facing camera and its associated calibration steps, as the same camera can determine both device position and orientation by imaging features through the transparent spindle and directly on the 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
Achieves sub-micron precision alignment of electronic devices on a substrate without sacrificing valuable surface area, maintaining accuracy despite thermal and friction impacts.
Implementation Method 1
a downward facing camera movable above the spindle during picking and placement of an electronic device by the spindle, and configured to image outer edges of the electronic device during the placement stroke of the spindle through the transparent spindle body
Implementation Method 2
fine adjustments using piezo stages for sub-micron accuracy
Data Source
AI summary
An electronic device placement system includes a spindle assembly having a positioning system configured to move between a picking location and a placement location, the spindle assembly including a spindle having a transparent spindle body and a vertical nozzle, an upward facing camera configured to image a bottom of an electronic device picked up by the nozzle of the spindle prior to a placement stroke of the electronic device, and a downward facing camera movable above the spindle during picking and placement of an electronic device by the spindle. The downward facing camera is configured to image outer edges of the electronic device during the placement stroke of the spindle through the transparent spindle body and to capture an image of a surface of a substrate prior to and/or during the placement stroke.