Wafer Probe Alignment Control Using Historical Offset Correction
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Solution Overview
Problem
Current wafer testing methods rely on manual alignment of probe cards with test pads, which is inefficient and prone to errors, especially with smaller devices and larger wafers, leading to potential damage and increased testing time.
Innovation Solution
A system and method using alignment pads with distinct electrical characteristics to facilitate automated alignment through a wafer test system, employing historical and regression analysis to determine alignment factors for precise probe card positioning, reducing manual intervention and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If human operators visually inspect alignment, then alignment can be performed without complex equipment, but alignment efficiency is low and error-prone
Solution Approach 1:
The patent replaces manual visual inspection with an automated optical alignment system that uses imaging sensors and computer processing to detect and measure probe-wafer alignment, eliminating the need for human operators to visually inspect while significantly improving alignment efficiency and accuracy
Solution Approach 2:
The system enables self-alignment by allowing the alignment system to automatically detect misalignment conditions and control the positioning mechanism to correct alignment, reducing reliance on human operators and improving productivity
2Reliability
If probe card is removed and reapplied for realignment, then alignment can be corrected, but time is lost and damage risk increases
Solution Approach 1:
The system performs preliminary alignment detection before the probe card is applied to the wafer, and continues to monitor alignment during the bonding process, allowing real-time correction without removal and reaplication of the probe card
Solution Approach 2:
The alignment system provides continuous feedback on probe-wafer alignment status during the bonding process, enabling real-time adjustments to maintain proper alignment without requiring time-consuming removal and reaplication of the probe card
3Measurement precision
If microscopy tools are used for visual alignment, then alignment precision can be improved, but cost increases prohibitively
Solution Approach 1:
The patent replaces expensive microscopy tools with a more cost-effective optical imaging system that uses standard imaging sensors and computer processing to achieve the same or better alignment precision, reducing device complexity and cost
Solution Approach 2:
The alignment system uses a multi-functional approach that combines imaging, measurement, and control capabilities in a single integrated system, eliminating the need for separate expensive microscopy equipment while maintaining high alignment precision
4Reliability
If operators are highly qualified, then alignment accuracy can be maintained, but operational costs increase
Solution Approach 1:
The system performs alignment detection and correction automatically without requiring highly qualified operators, using automated image processing and control algorithms to maintain high alignment accuracy while reducing operational complexity and costs
Solution Approach 2:
The patent replaces human operator expertise with automated computer-based alignment algorithms and image processing techniques, maintaining high alignment accuracy while eliminating the need for highly qualified and expensive operators
Data Source
AI summary
A system and method for aligning a probe, such as a wafer-level test probe, with wafer contacts is disclosed. An exemplary method includes receiving a wafer containing a plurality of alignment contacts and a probe card containing a plurality of probe points at a wafer test system. A historical offset correction is received. Based on the historical offset correct, an orientation value for the probe card relative to the wafer is determined. The probe card is aligned to the wafer using the orientation value in an attempt to bring a first probe point into contact with a first alignment contact. The connectivity of the first probe point and the first alignment contact is evaluated. An electrical test of the wafer is performed utilizing the aligned probe card, and the historical offset correction is updated based on the orientation value.