Probe Card Stroke Compensation via Measured Flatness
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Solution Overview
Problem
Existing probe card systems in semiconductor wafer testing struggle to ensure effective contact between probes and wafer pads, leading to yield and reliability issues due to inadequate stroke compensation.
Innovation Solution
A probe card stroke compensation system that includes a measuring unit to assess probe stroke and flatness, and a pressure sensor unit to calculate and adjust the stroke compensation value, ensuring accurate and reliable contact between probes and wafer pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the probe stroke is increased to ensure effective contact between probe and wafer pad, then the contact reliability is improved, but the probe card structural strength and precision requirements worsen
Solution Approach 1:
The system performs preliminary measurement of probe stroke and flatness before actual testing, calculates the required compensation value in advance, and pre-adjusts the probe card position to ensure effective contact without requiring excessive structural strength during testing
2Productivity
If the number of probes is increased to meet high-density market demand, then the productivity is improved, but the total thrust requirement and device complexity worsen
Solution Approach 1:
The system divides the probe card into multiple probe units, each with individual stroke measurement and compensation capabilities. The measuring unit and pressure sensor unit are segmented to work independently on different probe regions, allowing high probe counts without proportionally increasing overall system complexity
Solution Approach 2:
The system changes the control parameter from direct mechanical thrust control to stroke-based compensation control. By measuring and compensating individual probe stroke parameters, the system can handle high probe densities without requiring proportional increases in total thrust capability
3Force
If the probe elastic force is increased to ensure effective contact, then the contact pressure is improved, but the probe deformation and stroke requirements worsen
Solution Approach 1:
The system uses pressure sensors to provide feedback on actual contact force, which is then used to adjust and compensate probe stroke in real-time. This feedback mechanism ensures adequate contact pressure without requiring excessive probe deformation or stroke
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
The system effectively compensates for probe stroke, ensuring consistent and reliable electrical contact, thereby improving the yield and reliability of semiconductor wafer testing.
Implementation Method 1
a pressure sensor unit, the pressure sensor and the probe head can be replaced with each other, and the stroke compensation value of the probe card is obtained according to the relationship between the pressure and the stroke measured by the pressure sensor
Implementation Method 2
After the probe is stuck on the wafer pad, it is necessary to continue to apply pressure to make the probe deform and generate greater elastic force, thus ensuring the electrical contact between the probe and the pad
Data Source
AI summary
The invention provides a probe card stroke compensation system, which can be applied to a wafer testing system, and that probe card in the wafer testing system includes a probe head, comprising a measuring unit, which is used for measuring the stroke of a single probe and the flatness of all probes, and allows to calculate the total elastic force of the probe card according to the numerical values of the stroke and flatness; a pressure sensor unit, wherein that pressure sensor and the probe head can be replaced each other, and the stroke compensation value of the probe card is obtained according to the relationship between the pressure and the stroke measured by the pressure sensor. The invention also provides a probe card stroke compensation method correspondingly.