《Applications Notes for 0201 printing on MPM printers Final 5Feb03》.doc

APPLICATIONS NOTE Speedline Technologies Asia, 150, Kampong Ampat, Ka Centre, #05-08, Singapore 368324 hlee@ January 14, 2003 Applications Notes for 0201 printing on MPM Printers Introduction : Miniaturizing of some consumer products such as mobile handphones, lap-tops and digital cameras is an ongoing activity. This gives rise to the need of smaller and smaller components such as micro-BGAs, CSPs(Chip Scale Package)and extremely small capacitors resistors such as 0201’s. This Application Notes is written for experienced users of Solder-Paste Printing machines preferably MPM printers. Detailed information on pad designs, specific parameters’ description, solder-paste volume deposition matrix, stencil fabrication methods and calculation methods are available in other published papers and will not be discussed here. Stencil Design : An aspect ratio of 1.5 and an area ratio of 0.66 must be achieved for any successful and consistent printing. An E-fab stencil is preferred for fine/micro apertures but a laser edge stencil is acceptable. There are many possible pad dimensions. For this case study, we will use a 15 mils(0.015” or 0.38mm) by 12 mils(0.012” or 0.3mm) for X Y sides. An aperture reduction of 20% used on a 4 mils(0.004” or 0.1mm) thick stencil will gives us an aspect ratio of 2.5 and an area ratio of 0.681. This stencil design results in approximately 331 cubic mils of solder paste being deposited. This satisfies minimum requirement of 330 cubic mils of solder paste volume for good adhesion of terminals to pads for 0201 components. If a 10% aperture reduction is chosen, we would expect a solder paste volume of 344 cubic mils deposited. This stencil design may be considered if the particular product or quality standards require a “margin of safety”. This stencil design must consider the solder paste volume requirements for other components. A 3 mils thick stencil is desired for best release of solder paste but will be considered too thin/insufficient