Prober Probe Height Detection and Camera Collision Prevention
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Solution Overview
Problem
Existing semiconductor wafer testing techniques face challenges in accurately detecting probe positions and heights, leading to potential collisions between probe position detecting cameras and probes, which can result in errors and decreased throughput due to operator errors or changes in probe card configurations.
Innovation Solution
A prober system equipped with a separate probe height detector and a first height adjusting mechanism that allows for precise detection of probe heights, preventing collisions by adjusting the position of the probe position detecting camera based on the detected height, and incorporating a contact-type probe height detector for accurate and quick height measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the probe position detecting camera is moved upward along the Z-axis direction to focus on the probe tips, then the detection accuracy of probe positions is improved, but the risk of collision between the camera and probes increases
Solution Approach 1:
The system performs preliminary detection of probe heights using the probe height detector before moving the probe position detecting camera upward. Based on the detected heights, the system calculates appropriate Z-axis positions for the camera, ensuring it focuses on probe tips without colliding with them. This preliminary measurement action prevents collision while maintaining detection accuracy.
Solution Approach 2:
The probe height detector serves as an intermediary device between the probes and the probe position detecting camera. It first measures the probe heights and provides this information to the control unit, which then uses it to position the camera at a safe distance. This intermediary measurement process enables accurate camera positioning without direct contact or collision risk.
2Measurement precision
If the probe position detecting camera is used to detect probe tips, then relative positional alignment between wafer electrodes and probes is achieved, but the throughput of the prober is degraded due to focusing time
Solution Approach 1:
The system performs preliminary height detection using the probe height detector before the probe position detecting camera needs to focus on the probe tips. By obtaining probe height information in advance, the camera can be positioned directly at the correct Z-axis level without time-consuming focusing operations, thus maintaining alignment accuracy while improving throughput.
Solution Approach 2:
The system replaces the camera's automatic focusing mechanism (which is time-consuming) with a mechanical positioning approach. The control unit moves the camera to a predetermined Z-axis position based on probe height data from the probe height detector, eliminating the need for iterative focusing and significantly reducing the time required for positional alignment.
3Adaptability or versatility
If probe card replacement is performed to adapt to different chips and measurement purposes, then the versatility of the prober is improved, but the risk of collision increases due to changes in probe lengths and positions
Solution Approach 1:
After probe card replacement, the system performs preliminary detection of the new probe heights using the probe height detector before any camera movement or measurement operations. This ensures that the system adapts to the specific probe configuration of the replaced card, establishing safe operating parameters that prevent collision while maintaining versatility for different measurement purposes.
Solution Approach 2:
The probe height detector provides continuous feedback about probe heights to the control unit. When a probe card is replaced, the system receives new height information, updates its internal parameters, and adjusts camera positioning accordingly. This feedback mechanism ensures that the system adapts safely to different probe card configurations, maintaining both versatility and collision prevention.
Data Source
AI summary
A prober for preventing a collision between a probe and a probe position detecting camera and a prober operation method are provided. A prober that performs an inspection by bringing a probe into contact with an electrode of a wafer W includes: a probe position detecting camera for detecting the position of the tip of the probe to perform relative positional alignment between the electrode of the wafer W and the probe; a probe height detector, provided separately from the probe position detecting camera, for detecting the height of the tip of the probe from a reference plane serving as a reference for the height of the probe position detecting camera; and a first height adjusting mechanism for changing the height of the probe position detecting camera from the reference plane, based on the detection result of the probe height detector.