Technical Library | 2020-08-27 01:22:45.0
Initially adopted internal specifications for acceptance of printed circuit boards (PCBs) used for wire bonding was that there were no nodules or scratches allowed on the wirebond pads when inspected under 20X magnification. The nodules and scratches were not defined by measurable dimensions and were considered to be unacceptable if there was any sign of a visual blemish on wire-bondable features. Analysis of the yield at a PCB manufacturer monitored monthly for over two years indicated that the target yield could not be achieved, and the main reasons for yield loss were due to nodules and scratches on the wirebonding pads. The PCB manufacturer attempted to eliminate nodules and scratches. First, a light-scrubbing step was added after electroless copper plating to remove any co-deposited fine particles that acted as a seed for nodules at the time of copper plating. Then, the electrolytic copper plating tank was emptied, fully cleaned, and filtered to eliminate the possibility of co-deposited particles in the electroplating process. Both actions greatly reduced the density of the nodules but did not fully eliminate them. Even though there was only one nodule on any wire-bonding pad, the board was still considered a reject. To reduce scratches on wirebonding pads, the PCB manufacturer utilized foam trays after routing the boards so that they did not make direct contact with other boards. This action significantly reduced the scratches on wire-bonding pads, even though some isolated scratches still appeared from time to time, which caused the boards to be rejected. Even with these significant improvements, the target yield remained unachievable. Another approach was then taken to consider if wire bonding could be successfully performed over nodules and scratches and if there was a dimensional threshold where wire bonding could be successful. A gold ball bonding process called either stand-off-stitch bonding (SSB) or ball-stitch-on-ball bonding (BSOB) was used to determine the effects of nodules and scratches on wire bonds. The dimension of nodules, including height, and the size of scratches, including width, were measured before wire bonding. Wire bonding was then performed directly on various sizes of nodules and scratches on the bonding pad, and the evaluation of wire bonds was conducted using wire pull tests before and after reliability testing. Based on the results of the wire-bonding evaluation, the internal specification for nodules and scratches for wirebondable PCBs was modified to allow nodules and scratches with a certain height and a width limitation compared to initially adopted internal specifications of no nodules and no scratches. Such an approach resulted in improved yield at the PCB manufacturer.
Parts & Supplies | Pick and Place/Feeders
Product Description: Product Name: Philips smt feeder station(with power supply) Product Size (mm): L120*W230*H250 Brand:Philips Devices Number : Install one FEEDER Applicable models: Philips Series models Weight: About 6KG This product is ma
Used SMT Equipment | Pick and Place/Feeders
Excellent condition with only minor scratches comes with several new tape feeders. A nice machine for entry level or prototype labs. This machine has seen little use came out of an R&D laboratory
New Equipment | Test Equipment
The Micro Scratch Tester is widely used to characterize adhesion failure of thin films and coatings, with a typical thickness below 5 µm. The MST is also used in the analysis of organic and inorganic; soft and hard coatings. Applications include thin
Nanovea Mechanical Testers provide unmatched multi-function Nano and Micro/Macro modules on a single platform. Both the Nano and Micro/Macro modules include scratch tester, hardness tester and wear tester modes providing the widest and most user frie
Used SMT Equipment | Pick and Place/Feeders
Near new Agilis M8 magazine. No scratches or marks, very little use. Removed from our own machine. Magazine is excess to current requirements. Also have a quantity of near new yellow / white feeders available for $200 US each. You choose the qua
Industry Directory | Manufacturer
CSM Instruments develops, manufactures and sells instruments to characterize mechanical properties of surfaces. We have been the world leader in this market for more than 30 years.
Industry News | 2016-12-21 11:15:14.0
Driven by emerging technology and to suit customer special requirements XYZTEC Condor Sigma's comprehensive range of bond tests is always increasing. One of our latest applications made scratch testing of complex coating much easier to achieve and increased throughput by several orders of magnitude.
Industry News | 2016-12-21 11:15:27.0
Driven by emerging technology and to suit customer special requirements XYZTEC Condor Sigma's comprehensive range of bond tests is always increasing. One of our latest applications made scratch testing of complex coating much easier to achieve and increased throughput by several orders of magnitude.
Industry News | 2016-12-21 11:14:01.0
Driven by emerging technology and to suit customer special requirements XYZTEC Condor Sigma's comprehensive range of bond tests is always increasing. One of our latest applications made scratch testing of complex coating much easier to achieve and increased throughput by several orders of magnitude.