A Buyer's Checklist for a High-Precision Push-Pull Testing Machine.

A push-pull testing machine, known in the industry as a bond tester, is a specialized instrument used to measure the mechanical strength of the tiny connections inside electronic and semiconductor devices. Its primary purpose is to perform quality control by applying precise push (shear) or pull (tensile) forces to these connections until they fail, thus determining their strength. Key applications include wire bond pull testing, where it hooks and pulls a wire to ensure it is properly attached; ball shear testing, where it pushes on a solder ball to test its adhesion to a circuit board pad; and die shear testing, which measures the strength of the adhesive holding a silicon chip onto its package substrate. This data is critical for manufacturers to ensure their products are robust enough to withstand the stresses of assembly and everyday use, preventing field failures and ensuring long-term reliability.

Selecting the right push-pull testing machine requires a careful evaluation of your specific applications. First, identify the types of tests you need (e.g., wire pull, die shear, ball shear). This will determine the required test modules or heads. Second, determine the force ranges needed for each test. A machine used for fine gold wire will need a very sensitive low-force sensor, while a machine for large die shear will need a high-force capability. Look for a system with interchangeable load cell cartridges for maximum flexibility. Third, consider the level of automation and the required throughput. Manual or motorized stages may be sufficient for a lab, while a fully automated system might be needed for high-volume production. Finally, evaluate the software capabilities, ensuring it can perform the necessary analysis and generate reports that meet your quality standards. Consulting with an expert at WBE can help you navigate these options to configure the perfect push-pull testing machine.

The data from a push-pull testing machine provides much more than just a peak force number; proper interpretation is key to process improvement. The numerical force value tells you the strength, but the failure mode tells you why it failed. For example, in a wire bond pull test, a "wire break" in the middle indicates a good, strong bond, while a "ball lift" (the entire bond lifts off the pad) points to a problem with the bonding surface or parameters. The software on a WBE machine helps operators log these JEDEC-standard failure modes. Analyzing the distribution of these modes, along with statistical data like the mean force and standard deviation (Cpk), gives engineers a complete picture of their process health. A high average strength with a low standard deviation and a desirable failure mode distribution is the hallmark of a stable, high-quality manufacturing process, all revealed by the data from a push-pull testing machine.

When using a push-pull testing machine, engineers can choose between two fundamental methods: destructive and non-destructive testing. Destructive testing is the most common method used for process control. It involves testing a sample of components to failure to determine the absolute maximum strength of the bonds. This provides valuable statistical data about the health and capability of the manufacturing process. Non-destructive testing, on the other hand, is used for 100% screening of very high-reliability devices, such as those used in military or space applications. In this test, the machine applies a proof force—a force that is significant but well below the expected breaking point—to every single wire bond. If a bond survives, it is certified as meeting a minimum strength requirement. WBE's push-pull testing machine can be precisely programmed to perform both types of tests accurately.