Probe Card Inspection Using Optical Dot Pattern Alignment
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Solution Overview
Problem
Existing inspection methods for semiconductor devices face challenges in accurately adjusting the relative positional relationship between probe tips and test pads, especially due to thermal expansion and stage movement, leading to potential deviations during high-temperature preheating and inspection.
Innovation Solution
The inspection apparatus employs two movable camera units to project and receive an optical dot pattern, allowing for the detection of optical axis differences, including position and inclination differences, to accurately adjust the stage position and orientation of the semiconductor wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stage is moved to bring probe tips into contact with test pads, then the inspection process can be performed, but thermal expansion and stage movement cause positional deviations between probe tips and test pads
Solution Approach 1:
The system performs preliminary measurement of the optical dot pattern position before the actual inspection. By capturing images of the optical dots at multiple positions and calculating their relative positional relationships in advance, the system establishes reference data that compensates for thermal expansion and stage movement effects during the inspection process
Solution Approach 2:
The system continuously monitors the position of optical dots using image capture devices and feeds this information back to the control unit. Based on the detected positional deviations of optical dots from their reference positions, the system dynamically adjusts the stage position to maintain accurate alignment between probe tips and test pads
2Measurement precision
If multiple optical dots are measured to detect position differences, then alignment accuracy improves, but the complexity of image processing and calculation increases
Solution Approach 1:
The measurement process is divided into discrete segments: individual optical dots are detected separately in image processing, their coordinates are extracted independently, and then the position difference is calculated by comparing these segmented data points against reference positions. This segmentation simplifies the overall complex measurement task into manageable steps
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 method enables precise alignment of probe tips with test pads, ensuring accurate electrical characteristic inspections of semiconductor devices by effectively compensating for thermal-induced deviations and maintaining contact accuracy.
Implementation Method 1
projecting, by a projector, an optical dot pattern in which optical dots are arranged; receiving the optical dots by a light receiver
Data Source
AI summary
An adjustment method is provided for an inspection apparatus configured to inspect an inspection object by bringing a tip of a probe disposed on a probe card into contact with an electrode disposed on the inspection object. The method includes projecting, by a projector, an optical dot pattern in which optical dots are arranged, receiving the optical dots by a light receiver, capturing a standard image including the optical dots projected by the projector, capturing a measurement image including at least two of the optical dots of the optical dot pattern received by the light receiver, and adjusting a stage on which the inspection object is disposed, according to the standard image and the measurement image.