SMART Microsystems’ William Boyce Discusses “Destructive Wire Bond Pull Testing and Its Purpose” in the Fall Issue of the MEPTEC Report
In the previous article, destructive wire bond shear testing was discussed. In this article we will discuss the practice and purpose of the destructive wire bond pull test. The reason that we chose to discuss wire bond pull testing after examining shear testing is that, in concurrence with the development process of a wire bond, we perform pull testing only after shear testing has been performed. The destructive pull test is explicitly what it sounds like. A wire bond loop is pulled until it fails in one of three ways: bond lift, heel break, or mid-span break. The pull test measures the force required to break the wire from tensile force, and the remnants of the wire bond are used to determine the failure mode. Typically used to develop the wire bond process, destructive pull testing is also used as a statistical process control in production bonding.
SMART Microsystems’ William Boyce Discusses “Destructive Wire Bond Shear Testing and Its Purpose” in the Summer Issue of the MEPTEC Report
The process of wire bonding a wire to a substrate is simply the joining of two metals through force and vibration. The best way to determine the strength and integrity of that weld, is by shearing the weld with a blade to evaluate not only the force required to shear the joint (shear strength), but also to determine the total amount of the intended weld area that is actually welded (nugget size) as a percent of the intended weld area. The wire bond shear test is not a replacement or substitute for the pull testing, but rather a completely different test, with a different purpose and intent, typically used to develop the wire bond process. Shear testing is the often the forgotten or unknown method of testing wire bonds. Perhaps because it has been conspicuously missing from mil STD883 it has gone largely unknown as a testing tool in the new product development process design cycle.
SMART Microsystems’ William Boyce Discusses “Destructive Wire Bond Testing for Development and Production” in the Spring Issue of the MEPTEC Report
Wire bonding is generally considered the most cost-effective and flexible interconnect technology and is used to assemble the vast majority of semiconductor packages. In fact, over 15 trillion interconnects are formed by wire bonding each year. With that said wire bonding interconnects have also long been the bane of the existence of many process and manufacturing engineers. The process engineering and development takes extensive effort involving destructive pull and shear testing as well as multifactorial design of experiments. Once the process is developed and released to manufacturing, the manufacturing engineering teams are tasked with the responsi-bility of keeping the process centered in the process window, also requiring some level of destructive testing.
SMART Microsystems’ William Boyce Discusses “Quality Management Systems in the Microelectronic Assembly Business” in the Winter Issue of the MEPTEC Report
There are many quality management systems that are used in the microelectronic assembly business. AS9100 is for aerospace, IATF for automotive, ISO13485 for medical, ISO17025 for calibration and test labs, just to mention a few. Most of these standards are based from the ISO9001 QMS, and for good reason, ISO 9001 is viewed by most people as the minimum table stakes of good business practice. At SMART Microsystems, we have chosen to be ISO 9001-2015 registered, completing our third annual reassessment external audit in November.