Emerald Group Publishing Limited
Copyright © 2011, Emerald Group Publishing Limited
Photo Stencil poster chosen best at IPC APEX EXPO 2011
Article Type: Industry news From: Circuit World, Volume 37, Issue 3
Photo Stencil, a leading full-service provider of high-performance stencils and tooling, announced that the poster presented by Dr William Coleman, titled Stencil design for broadband printing (very small and normal components on the same PCB), was chosen by the Technical Program Committee of IPC as “Best Poster of the Technical Conference” for the 2011 IPC APEX EXPO, held 12-14 April 2011 in Las Vegas, Nevada. IPC-Association Connecting Electronics Industries® celebrates the best of electronic interconnection research being conducted by both industry leaders and academia.
The poster analyses three stencil printing options for applying solder to boards that are populated with both very small pitch 0.4 mm devices as well as larger pitch devices such as 0.5 mm, 0.65 mm and 1 mm. Normally, the stencil should be at least 100 μm thick for normal devices to achieve acceptable solder fillets. However, at this thickness, the area ratio (solder paste ability to release from the stencil aperture) is well below the minimum acceptable value of 0.66 for most stencils and 0.50 for some special electroform stencils needed for these small devices. An aperture size of 175 μm in a 100 μm stencil is required for acceptable paste transfer for these very small devices.
As the poster demonstrated, testing showed that incorporating a nano-coating to an already smooth aperture wall surface of electroform and NicAlloy-XT stencils improves lubercisity of the wall surface to promote better paste transfer for the very small apertures associated with 0.4 mm chip scale packages and 01005 devices.
For more information, visit web site: www.photostencil.com