Today we want to discuss a topic related to printed circuit board finishes that significantly influence the results of a final assembly (PCBA).<\/p>\n
Generally, the main factor in choosing a PCB finish is the final application.<\/p>\n
Sometimes, economic reasons lead to choices and\/or compromises that end up \u201cundermining\u201d the result<\/strong>.<\/p>\n We won’t evaluate what’s already in the market, as enough has been written about that, but instead we’ll focus on a single finish that’s still relatively unknown, yet pioneering excellent quality results and where great expectations are placed:<\/p>\n This is a highly reliable technology that involves the \u201cdirect application of a gold layer (averaging 0.2 \u00b5m) over copper, without the\u201d interposition of other materials such as nickel or palladium.<\/p>\n This factor, besides quality and reliability, brings significant benefits in all applications working at high frequencies<\/strong>.<\/p>\n The solder joint created with this finish is one of the best in terms of integrity and long-term reliability, and it can also be used in \u201cWire Bonding\u201d processes.<\/p>\n During the soldering phase, it helps create thin and uniform intermetallic layers. This has a beneficial effect and higher quality for joint strength, making it more resistant to \u201cfatigue\u201d and therefore more reliable over time since the intermetallic compound (IMC) created, Cu6Sn5, is the toughest. <\/p>\n The intermetallic layer formed with the DIG finish ensures better mechanical resistance, making it less sensitive to micro-cracks or breakage during thermal or mechanical stress.<\/p>\n The DIG finish has a thicker gold layer compared to the classic ENIG finish (IPC 4552) (chemical gold).<\/p>\n The DIG finish also has its pros and cons, which we analyze.<\/p>\n Reliability<\/strong>: offers excellent storage stability, maintaining surface properties unchanged over time.<\/p>\n High conductivity<\/strong>: \u201cgold has excellent conductive properties, thus improving the\u201d assembly performance.<\/p>\n Excellent solderability<\/strong>: makes the surface excellent for soldering in terms of both quality and planarity. Therefore, it’s beneficial where components such as BGA QFN etc. are present. <\/p>\n No \u201cblack pad\u201d phenomenon<\/strong>: unlike ENIG finish, the DIG process doesn’t involve Nickel.<\/p>\n Corrosion resistance<\/strong>: resistant to corrosion. This ensures long assembly life, even in difficult and hostile environments. <\/p>\n Solder joint integrity: <\/strong>excellent joint composition, with minimal intermetallics compound IMC: Cu6Sn5.<\/p>\n Currently, this finish has a high cost<\/strong>: gold is an expensive material and therefore this finish affects the final PCB price.<\/p>\n Currently, there are no standards regulating the DIG finish; manufacturers follow the technical specifications of the chemistry used.<\/p>\n Initial tests with this specific finish are very encouraging; we’ll keep you informed about reliability tests in the medium-long term, stay tuned!<\/p>\n In conclusion, soldering a board with DIG finish produces high-quality joints with minimal intermetallic formation, resulting in one of the best solder joints obtainable today, both in terms of reliability and durability.<\/p>\n","protected":false},"excerpt":{"rendered":" Today we want to discuss a topic related to printed circuit board finishes that significantly influence the results of a final assembly (PCBA). Generally, the main factor in choosing a PCB finish is the final application. Sometimes, economic reasons lead to choices and\/or compromises that end up \u201cundermining\u201d the result. We won’t evaluate what’s already […]<\/p>\n","protected":false},"author":1,"featured_media":6855,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":""},"categories":[38,43],"tags":[],"class_list":["post-7069","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-insights","category-printed-circuits"],"acf":[],"yoast_head":"\nDirect Immersion Gold, Known by the Acronym DIG<\/h2>\n
PROS<\/h2>\n
CONS<\/h2>\n