Rapid repairing method for superdense-pitch quad fiat no-lead (QFN) device on printed board assembly

A printed board and spacing technology, which is applied in the fields of printed circuit manufacturing, electrical components, printed circuits, etc., can solve problems such as difficult repair, difficult alignment, uncontrollable demoulding, etc., and achieve fast repair, high success rate, low cost effect

Active Publication Date: 2015-11-25
NO 8357 RES INST OF THE THIRD ACADEMY OF CHINA AEROSPACE SCI & IND
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For conventional QFN devices (Ptich is 1mm), use the commonly used method of printing solder paste on the PCB part or component end, and then use welding equipment to solder the device to achieve rework, but for ultra-fine-pitch QFN devices, Ptich less than 0.5mm, such as figure 1 For small and medium-sized DMLF packaged and tsCSP packaged devices, the above method has the problems of difficult alignment, uncontrollable solder tipping, sticking, and easy damage to solder paste during placement, and it is extremely difficult to repair, and the success rate of one repair is less than 10%. %

Method used

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  • Rapid repairing method for superdense-pitch quad fiat no-lead (QFN) device on printed board assembly
  • Rapid repairing method for superdense-pitch quad fiat no-lead (QFN) device on printed board assembly

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Embodiment 1

[0026] Below in conjunction with example 1, the process method of the ultra-fine pitch QFN device on the fast repair printed board assembly of the present invention is introduced: use the ERSAIR550A / PL550A rework workstation to repair the ultra-fine pitch QFN device on the DMLF package form on the printed board assembly.

[0027] 1. Solder paste for printing ultra-fine-pitch QFN devices in the form of DMLF packages to be repaired. The specific method is to use the stencil used in the production of the printed board assembly to be reworked to directly transfer the solder paste to a flat steel sheet or thin plate with a solder mask effect.

[0028] 2. Attach the ultra-fine-pitch QFN device in the form of DMLF package to the printed solder paste. Mount MELF components to be reworked on the printed solder paste using equipment with alignment and mounting functions, namely ERSAIR550A / PL550A rework workbench;

[0029] 3. Melt the solder paste under the ultra-fine-pitch QFN device p...

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Abstract

The invention belongs to the technical field of application of quad fiat no-lead (QFN) devices, particularly relates to a rapid repairing method for a superdense-pitch quad fiat no-lead (QFN) device on a printed board assembly, and aims at improving the repairing success rate. The rapid repairing method is particularly applied to rapid repairing of the superdense-pitch QFN device on the printed board assembly in electric installation. According to the technical scheme, soldering paste is arranged at the end of a component in advance and forms a solder column after being fused, and then rapid and reliable repairing of the device is realized through a mounting method; the first repairing success rate is 100%; printing can be realized by a steel mesh during production of the repaired printed board assembly; the required steel mesh does not need to be individually customized; and the rapid repairing method has the characteristics of high efficiency, high success rate and low cost. According to the rapid repairing method, the problem of low success rate caused by a conventional QFN device repairing technique is solved; and rapid repairing of the superdense-pitch QFN device is realized.

Description

technical field [0001] The invention belongs to the technical field of application of QFN devices, and in particular relates to a rapid repair method for ultra-fine-pitch QFN devices on printed board assemblies, which improves the success rate of repair and is specifically applied to ultra-dense pitches on printed board assemblies in electrical assembly Rapid rework of QFN devices. Background technique [0002] With the application of QFN devices with ultra-fine pitch (Ptich less than 0.5mm) on printed board components in military products, the rework of QFN devices has become a key factor restricting the quality of rework. In rework, solder must be used to electrically connect the pads on the printed board assembly to the pads of ultra-fine-pitch QFN devices. For conventional QFN devices (Ptich is 1mm), use the commonly used method of printing solder paste on the PCB part or component end, and then use welding equipment to solder the device to achieve rework, but for ultra...

Claims

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Application Information

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IPC IPC(8): H05K3/34
CPCH05K3/34H05K2203/176
Inventor 苟俊锋曾立云谭磊焦淑萍
Owner NO 8357 RES INST OF THE THIRD ACADEMY OF CHINA AEROSPACE SCI & IND
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