How to solder the side of QFN components in SMT assembly?

SMTIt is often found in products processed by surface mount technologyQFNEncapsulated componentsQFNThat is, a square flat leadless package.QFNEncapsulated inSMTIt is one of the more difficult packages in surface mount technology, mainly because there are no epitaxial pins. inSMTIt sometimes occurs during processingQFNProblems such as the side pads of the packaged components not being soldered or the solder climbing height not meeting the requirements. Below is Shenzhen JJYSolder paste manufacturerLet me give you a brief introduction.

Some people thinkQFNThe side pads also need to be joinedQFPIn fact, only when the pins are fully tinned can it be considered that the soldering is normalQFNThe soldering effect of the packaged device is still determined by the bottom solder. Usually, the side soldering is carried out according to the customer's requirements.IPC-A-610The standardQFNThe requirements for solder climbing on the side pads are divided into three grades;1The level isQFNThe bottom of the solder pad is filled with tin for obvious wetting.2The grade is of the height of the side pad25%;3The grade standard is for the height of the side pads50%. Now let me give you a brief introduction toSMTHow to give in surface mount technology (SMT) processingQFNTin the side of the component:

1By using the steel mesh hole opening method of internal cutting and external pulling, the cross-cutting size at the pad position is reduced through internal cutting, thereby reducing the occurrence of solder bonding, bridging and other issues during the welding processSMTThe phenomenon of poor surface mount technology has spread outwardQFNThe openings of the steel mesh at the position of the chip pads have been increasedQFNPinSolder pasteQuantity, thereby ensuring that there is an adequate amount of tin for tin climbing.

2It is used in surface mount technology (SMT) processingQFNSpecial lead-free high-temperature solder pasteLFP-JJY5R-305T4orLFP-JJY5R-0307T4Etc., and increasing the amount of tin input during the steel mesh printing process can provide certain assistance for tin climbing.

3,QFNWhen the tin coating on the side is not good, it can be doneSMTBefore reflow soldering in surface mount processing, adding an appropriate amount of flux paste around the periphery will significantly improve the soldering solder crawling effect.

Shenzhen JJY Industrial Technology Co., Ltd. is a company15As a manufacturer specializing in the research and development and customization of solder paste, lead-free solder paste and leaded solder paste for many years, if you want to learn more about soldering knowledge, please continue to follow JJY Solder Paste Factory and leave a message online to interact with us.