Remote Counterweight Control for Wafer Probe Contacting
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Solution Overview
Problem
Automating the wafer probe contacting with chips on a wafer in manual wafer probe stations is challenging due to mechanical tolerances and the need for individual calibration in each setup, leading to potential contact loss or chip damage.
Innovation Solution
Implementing a remotely controlled counterweight mechanism that shifts the center of gravity of the tuner assembly, allowing precise tilting within mechanical tolerances to manage probe contact and release, using a counterweight attached to a rotating disc or handle, controlled by a stepper motor and timing belt, to ensure consistent and safe contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If manual wafer probe stations are used without automatic station, then device complexity is reduced, but ease of operation deteriorates due to challenging automation of probe contacting
Solution Approach 1:
A counterweight is attached to the tuner assembly to shift the center of gravity, enabling automated control of probe contact. The counterweight compensates for the mechanical limitations of the manual positioner by creating a tilting moment that reliably makes or breaks probe contact with the wafer chip, thus automating the operation without requiring a full automatic station.
2Measurement precision
If individual calibration is performed for each setup, then measurement precision is improved, but loss of time increases due to recalibration requirements
Solution Approach 1:
The counterweight is pre-positioned to establish the correct tilt angle for reliable probe contact. By performing the calibration action in advance and fixing the counterweight position, the system eliminates the need for repeated recalibration during different setups or measurement sessions, thus reducing time loss while maintaining precision.
3Manufacturing precision
If tuner is rigidly connected with wafer probes, then manufacturing precision is improved, but reliability deteriorates due to contact loss or chip damage risks
Solution Approach 1:
The counterweight creates a controlled tilting motion of the tuner assembly, allowing the rigidly connected probes to reliably make or break contact with the chip. This tilting mechanism absorbs mechanical tolerances and positioning variations, preventing contact loss and chip damage while maintaining the precision benefits of rigid connection.
Solution Approach 2:
The system introduces dynamic tilting motion to the otherwise rigid tuner-probe assembly. By allowing controlled angular movement through the counterweight mechanism, the system adapts to mechanical tolerances and ensures reliable contact without compromising the precision positioning capability of the rigid connection.
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
Enables automated and precise control of wafer probe contact and release, accommodating various manual tuner setups without the need for extensive recalibration, reducing the risk of contact loss or chip damage.
Implementation Method 1
mounting a remotely controlled counterweight and moving it to tilt the tuner assembly
Implementation Method 2
moving it to tilt the tuner assembly within the unavoidable tolerances of the 3-axis positioner
Data Source
AI summary
An on-wafer load pull tuner system includes an intelligent, universal, remotely controlled, mechanical wafer-probe contact controlling device, supporting automatic microwave single or multi-probe balanced slide screw tuners. It allows contacting and stable on-wafer testing of sub-micrometric devices. Ultra-low loss rigid airlines (bend-lines) used to connect the tuner with the semiconductor chips, in order to improve the tuning range at the DUT reference plane, transfer mechanical contact control movements of the wafer probes attached to the rigid bend-lines, when a counterweight tilts the tuner assembly by controlling the center of gravity of the assembly.