High-reliability application printed circuit board assembly QFN assembling and welding pretreatment method

Abstract

The invention discloses a high-reliability application printed circuit board assembly QFN assembling and welding pretreatment method. The method comprises the following steps that 1) a carrying plateis manufactured; 2), a mesh plate is manufactured, at least one through hole corresponding to a QFN chip bonding pad is formed in the mesh plate, and the through holes form a through hole array; 3) dehumidification treatment is carried out on a QFN chip; 4), the mesh plate and the carrying plate are cleaned; 5) the mesh plate is placed on the carrying plate, and a soldering paste containing a soldering flux is printed on the carrying plate through the through hole array; 6) the QFN chip is pasted on the carrying plate with the soldering paste by a chip mounter; 7) hot air reflow soldering processing is performed on the carrying plate pasted with the QFN chip; and 8) the carrying plate pasted with the QFN chip is immersed into a cleaning agent so as to dissolve the soldering flux residue, and the QFN chip is separated from the carrying plate to complete the pre-tin coating. According to the method, the weldability of the QFN chip bonding pad is better through the pre-tin coating treatment, the welding qualification rate and reliability of the QFN chip can be improved, the stability and the service life of the printed circuit board assembly with high reliability are improved, and themaintenance cost of the system is reduced.

Description

technical field [0001] The invention relates to a printed circuit board manufacturing process, in particular to a high-reliability application printed circuit board component QFN assembly welding pretreatment method. Background technique [0002] With the development of multi-function and miniaturization of electronic products, the core of electronic product function realization - the density of printed circuit board components is getting higher and higher, which requires the electronic components used in them to be smaller in size and more comprehensive in functions; QFN (Quad Flat No-lead Package) chips with small size, light weight, low cost and outstanding electrical and thermal properties have become one of the most widely used surface mount devices. [0003] In the prior art, there are many welding methods for QFN chips. For example, the invention application with the application number of 2017105705 19.7 discloses a QFN chip, including a chip body, the chip body is p...

AI Technical Summary

Problems solved by technology

[0008] Aiming at the deficiencies in the prior art, the object of the present invention is to provide a kind of highly reliable application printed circuit board assembly QFN assembly soldering pretreatment method, this method can improve the uniformity of tin enamel of QFN pad, especially for batch manufacturing process, can Effectively improve the efficiency of tinning, improve the quality of solder joints, reduce the rate of bad rework, thereby reducing production costs, and solve the problems of low reliability of QFN solder joints in the prior art and prone to false soldering.

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