Solder paste printing yield improvement for SMT ultra fine pitch product by using six sigma technique

• Main Author: Lim, Kean Teik
• Format: Thesis
• Language: English; English
• Published: 2016
• Subjects: T Technology (General); TK Electrical engineering. Electronics Nuclear engineering
• Online Access: http://eprints.utem.edu.my/id/eprint/20512/1/Solder%20paste%20printing%20yield%20improvement%20for%20SMT%20ultra%20fine%20pitch%20product%20by%20using%20six%20sigma%20technique.pdf; http://eprints.utem.edu.my/id/eprint/20512/2/Solder%20paste%20printing%20yield%20improvement%20for%20SMT%20ultra%20fine%20pitch%20product%20by%20using%20six%20sigma%20technique.pdf; http://eprints.utem.edu.my/id/eprint/20512/; https://plh.utem.edu.my/cgi-bin/koha/opac-detail.pl?biblionumber=104960

Surface mount technology (SMT) is a method for producing electronic circuits in which the components are mounted directly onto the surface of printed circuit boards (PCBs). It has been emerged in the 1960s,gained momentum in the early 1980s and became widely used by the mid-1990s and is continually becoming more important as PCB assemblies become more advanced and compact with componentry real estate savings provided with SMT become more valuable and necessary.At presents,in the industry it has largely replaced the through-hole technology construction method of fitting components with wire leads into holes in the PCB because it allows for better electrical performance when compared to through-hole via and offers a conventional reflow processes compared to conventional wave solder.The majority of defects in PCB assembly are caused due to problem in the solder paste printing process or due to defects in the solder paste.There are various types of defects such as excessive solder paste,and solder melts and connects too many solder pads,which causes a short circuit. Insufficient solder paste result in incomplete circuits. When making PCBs,manufacturers often test the solder paste deposits using SPI (solder paste inspection).3D SPI systems measure the volume of the solder paste printed on solder pads before the components are applied and the solder reflow process.SPI systems can reduce the incidence of solder-related defects to statistically insignificant amounts.Yield improvement requires increased focus on stencil technology,printer capability,solder paste functionality and under stencil cleaning.The term of fine pitch is defining as 0.5mm in pitch and ultra fine pitch is 0.2mm - 0.4mm in pitch (Surface mount council,1999).The two major responses from the experimentation are printing quality and SPI yield.