Pull and Shear Testing
Royce Guest Blog Post: Universal Bond Tester for Hi-Rel Wire Bond & Die Attach Applications
Bond pull testing is a test for wire bond strength and a vital part of the process set-up of any wire bond program. The pull tester applies upward force, "pulling" the wire away from the die. The level of "pull" is recorded at each interval and then finally at the level at which the wire breaks away from the die.
There are two parts of a pull tester:
- A mechanism for applying the upward "pull" force, using a pull hook of some kind
- A calibrated instrument for measuring the force at which the wire inevitably breaks
Bond shear testing is a method for evaluating the strength of a ball bond. This test is complementary to pull testing and often is done in conduction with one another.
The two tests are necessary because both the bond and the wire must be strong enough at each end - these tests measure each end. With a bond shear test, the shearing arm is positioned beside the ball bond to be tested - the arm then "pushes" the ball off its bond pad. The force required to push the ball off its pad is its bond shear force. This is the metric measured alongside the pull test.
There are several methods of performing these tests. Palomar Technologies offers Royce Instruments Universal Bond Tester and Dedicated Wire Pull Tester. To learn more, download the data sheets.