One of the key issues in semiconductor parametric testing: probe contact resistance

PCB probe

The contact resistance of the probe is a key issue in semiconductor parametric testing. Contact resistance is the interlayer resistance between the probe tip and the solder joint when they come in contact with each other, and it has a significant impact on the measurement results.

The size of the contact resistance depends on a number of factors, including the material of the probe, the diameter and shape of the tip, the material of the solder, the contact pressure, and the flatness of the probe table. If the contact resistance is too high, it will lead to attenuation and distortion during signal transmission, thus affecting the accuracy of the test results.

In order to reduce the contact resistance, the following measures can be taken:

1. Select the appropriate probe material: tungsten rhenium alloy is a better choice because it has a smaller contact resistance and better fatigue resistance.

2. Control contact pressure: too high a contact pressure will damage the solder joints, too low may not be able to pass through the oxide layer, so you need to control the contact pressure properly.

3. Regular cleaning of the probe: the tip of the probe is easily contaminated, regular cleaning can reduce the change of contact resistance.

4. Keep the flatness of the probe table: the flatness of the probe table will affect the quality of the contact between the probe and the solder joint, so you need to keep the flatness of the probe table.

In addition to the above measures, attention needs to be paid to Balanced Contact Force (BCF), overdrive, probe-to-probe flatness, and probe contamination and cleaning to ensure the accuracy and reliability of test results.