Electronics Forum | Wed Oct 27 19:50:59 EDT 1999 | chris
Hi What is the possible cause of non-wetting of solder paste to the gold land pad. What we observed in the surface of the non-wet pad is an organic FM, and using FTIR we found out that it is a flux. It is possible that the cause of non-wetting is
Electronics Forum | Thu Apr 22 07:51:32 EDT 1999 | Vic Lau
after soldering transistors on a flex circuit (Ni/Au plated), one of the lead lift-up from the pad. under microscope (1,000 X), i find some cracks on the the pad surface. with edx analysis, the surface is mainly nickel. have you ever encounter suc
Industry News | 2003-03-14 08:18:03.0
The instruction is intended as a practical user's guide for determining if a failure is related to black pad.
Industry News | 2013-01-30 17:54:43.0
Design, assembly, inspection and repair personnel have a new tool to help improve reliability of ball grid arrays (BGAs) and fine-pitch ball grid arrays (FBGAs) in high density applications, thanks to the newly released C revision of IPC-7095, Design and Assembly Process Implementation for BGAs.
Technical Library | 2017-08-31 13:43:48.0
Wire bonded packages using conventional copper leadframe have been used in industry for quite some time. The growth of portable and wireless products is driving the miniaturization of packages resulting in the development of many types of thin form factor packages and cost effective assembly processes. Proper optimization of wire bond parameters and machine settings are essential for good yields. Wire bond process can generate a variety of defects such as lifted bond, cracked metallization, poor intermetallic etc. NSOP – non-stick on pad is a defect in wire bonding which can affect front end assembly yields. In this condition, the imprint of the bond is left on the bond pad without the wire being attached. NSOP failures are costly as the entire device is rejected if there is one such failure on any bond pad. The paper presents some of the failure modes observed and the efforts to address NSOP reduction
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.
ORION Industries | http://orionindustries.com/pdfs/silpad400.pdf
. Sil-Pad 400 actually improves its thermal resistance with age. The reinforcing fiberglass gives excellent cut-through resistance and Sil-Pad 400 is non-toxic and resists damage from cleaning agents
GPD Global | https://www.gpd-global.com/co_website/fluid-dispense-adhesive-application.php
. Using fluid beyond pot life can result in variable dispense results. Conductive Adhesive & Non-Conductive Adhesive Dispensing When dispensing conductive and non-conductive adhesives, we recommend using either our Precision Auger Pump or our Jet Pump , depending on application
COT specializes in high quality SMT nozzles and consumables for pick and place machines. We provide special engineering design service of custom nozzles for those unique and odd components.
2481 Hilton Drive
Gainesville, GA USA
Phone: (770) 538-0411
