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Reflow SMT Process

A reflow soldering and reflow soldering technology, applied in the direction of assembling printed circuits with electrical components, can solve the problems of reducing the reliability of the device, excessive contact resistance, and reducing the safe working area of ​​the device, and achieve the effect of reducing the generation of water vapor

Active Publication Date: 2019-08-30
杭州晶志康电子科技有限公司
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Among them, in the patch process, due to various factors, bubbles will be generated at the soldering place, and the existence of bubbles in the patch layer seriously affects the quality of the device, which can lead to excessive contact resistance and poor heat dissipation; it will also reduce the reliability of the device. properties, such as solder aging, intermetallic compound formation and delamination, eventually leading to chip cracking
The air bubbles will also increase the thermal resistance of the power MOS tube, causing the drift of many electrical parameters of the device, such as the increase of the on-resistance RDS, the drift of the threshold voltage, and the serious reduction of the safe working area of ​​the device.

Method used

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Examples

Experimental program
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Effect test

Embodiment 1-56

[0036] Embodiment 1-56: a reflow soldering patch process, comprising the following steps:

[0037] S0, drying, sending the circuit board to be soldered into an oven for pre-baking for 4-6H, and the drying temperature is 90-110°C;

[0038] S1. Printing solder paste. After the circuit board is detected correctly by the optical camera, the circuit board is pasted under the stencil, and the solder paste is passed through the mesh on the stencil while the lead-free scraper is moving above the stencil. The solder paste is printed on the circuit board through the hole, and the solder paste is Sn-Ag-Cu alloy solder. The mesh on the stencil is an inverted tapered round hole to increase the surface area of ​​the solder paste printed on the circuit board. ;

[0039] S2, placement, sending the circuit board after step S1 into the placement machine for placement;

[0040] S3. Intermediate inspection, check whether the polarity of the component is reversed, whether the mounting is offset,...

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Abstract

The invention discloses a reflow-soldering die bonding process. The process comprises the following steps of printing a solder paste, patching, intermediate inspection, reflow soldering and inspection after soldering. During the reflow soldering step, the pressure reduction treatment is conducted. In this way, the formation of cavities, due to the generation of huge air bubbles during the welding process, can be avoided. The formation of explosive exhausts, caused by the escaping of huge air bubbles, is also avoided. Since many fine tin beads are escaped, the negative pressure is formed in a welding zone through the pressure reduction treatment. Therefore, small air bubbles escape easily during the welding process, and huge air bubbles are not easily formed. The phenomenon of bead splashing is avoided.

Description

technical field [0001] The invention relates to a circuit board patching technology, in particular to a reflow soldering patching process. Background technique [0002] Due to the continuous miniaturization of electronic product circuit boards, chip components have appeared, and the traditional welding method can no longer meet the needs. With the development of surface mount technology, the reflow soldering machine as a part of surface mount technology has also been developed accordingly, and its application is becoming more and more extensive, and it has been applied in almost all electronic product fields. There is a heater in the welding cavity formed in the welding box of the reflow soldering machine, so that the components on the circuit board in the welding cavity can be welded together with the circuit board through the melted solder paste. [0003] Existing patching process such as the application publication number is CN104694029A, the application date is a kind o...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H05K3/34
Inventor 王熠超
Owner 杭州晶志康电子科技有限公司
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