CN210225926U

CN210225926U - PCB board for preventing module chip secondary reflow soldering paster from flying

Info

Publication number: CN210225926U
Application number: CN201920872922.XU
Authority: CN
Inventors: Zhiqi Zhang; 张志其; Huihui Yu; 余辉辉; Dandan Fan; 范丹丹
Original assignee: Shenzhen Small Rui Polytron Technologies Inc
Current assignee: Shenzhen Small Rui Polytron Technologies Inc
Priority date: 2019-06-11
Filing date: 2019-06-11
Publication date: 2020-03-31
Anticipated expiration: 2029-06-11

Abstract

The utility model relates to a prevent PCB board of module chip secondary reflow soldering paster fly up, it includes the module chip, the module chip paste in the PCB board, the module chip has the ground connection pad, be equipped with the through-hole on the ground connection pad, the PCB scrubbing brush has the tin cream in order to produce the motion when module chip reflow soldering and promote gaseous motion extremely the through-hole, and pass through-hole exhaust gas. Through the through hole exhaust gas, the paster is effectively prevented from flying when the module chip is subjected to secondary reflow soldering, and good quality of products is guaranteed.

Description

PCB board for preventing module chip secondary reflow soldering paster from flying

Technical Field

The utility model relates to a PCB circuit board technical field, concretely relates to prevent PCB board of module chip secondary reflow soldering paster fly-up.

Background

Most of the current module chips are QFN packages, a large-size ground pad is arranged at the bottom of each chip, in order to enable the module to have a better performance effect, a plurality of through holes are required to be formed in the ground pad to be connected with each signal layer of a PCB, the through holes are required to be filled with oil by PCB manufacturers, based on the technology and price, the through holes can only be filled in 50% -70% by a plurality of PCB manufacturers at present, the module chips are attached to the PCB, partial gas can be remained under the chips after the chips are attached to the chips, and after the chips are attached to the chips in a secondary mode, the gas under the module chips is heated to affect expansion to push the chips up, so that the defects are caused.

SUMMERY OF THE UTILITY MODEL

In view of the above, it is desirable to provide a PCB capable of preventing the flying of the die pads during the second reflow of the module chip, so as to ensure the good quality of the product.

A PCB for preventing a module chip from flying up during secondary reflow soldering of the module chip comprises a module chip, wherein the module chip is attached to the PCB and provided with a grounding bonding pad, a through hole is formed in the grounding bonding pad, and the PCB is brushed with solder paste to move when the module chip is subjected to reflow soldering so as to push gas to move to the through hole and discharge the gas through the through hole.

Preferably, the through holes have various sizes, and the through holes with different sizes are designed according to different sizes of the grounding pads so as to be compatible with the performances of the grounding pads with different sizes and completely remove residual gas. .

Preferably, the PCB has a plurality of electrical layers, and the through hole is a cylindrical hole for connecting the plurality of electrical layers of the PCB.

Preferably, when the size of the ground pad is less than 4mm by 4mm, the ground pad is not provided with a through hole; when the size of the grounding pad is between 4mm and 4mm to 8mm, the grounding pad is provided with a through hole with the diameter of 0.6 mm; when the size of the grounding pad is larger than 8mm by 8mm, the grounding pad is provided with a through hole with the diameter of 0.8 mm.

In the PCB for preventing the secondary reflow soldering paster of the module chip from flying up, the grounding pad is provided with the through hole, the PCB is brushed with the solder paste, when the module chip is subjected to reflow soldering, the solder paste passing through the PCB and the module chip is diffused, diffused or reflowed and mixed, residual gas in a through hole which is not filled with oil on the PCB is discharged through the through hole, the module chip is completely pasted on the PCB, and the phenomenon that the gas below the chip is heated to influence expansion to push up the chip after the secondary reflow soldering paster is prevented from causing defects.

Drawings

Fig. 1 is a schematic diagram of a PCB board for preventing a module chip secondary reflow soldering patch from flying up according to an embodiment of the present invention.

Fig. 2 is a schematic diagram of a module chip of a PCB board for preventing a secondary reflow soldering patch of the module chip from flying.

Detailed Description

The present invention will be described in detail with reference to the following embodiments and drawings.

Please refer to fig. 1 and fig. 2, which illustrate a PCB 100 for preventing flying of a module chip secondary reflow soldering patch according to an embodiment of the present invention, which includes a module chip 2, the module chip 2 is attached to the PCB 100, the module chip 2 has a grounding pad 1 to make the PCB 100 have better electrical performance and facilitate heat dissipation of the chip, a through hole 11 is disposed on the grounding pad 1, and the PCB 100 is brushed with solder paste to generate movement during reflow soldering of the module chip 2 to push the gas to move to the through hole 11 and discharge the gas through the through hole 11. Preferably, the movement of the solder paste includes diffusion, diffusion or reflow mixing, etc.

Preferably, the PCB board 100 has a plurality of electrical layers, and the ground pad 1 is provided with a plurality of through holes to connect the electrical layers of the PCB board 100, so as to ensure that the PCB board 100 has normal electrical performance and communication performance. Preferably, in the embodiment of the present invention, the module chip 2 is a QFN package 12 to provide excellent electrical performance, and the ground pad 1 has a conductive pad 13 at the periphery thereof to realize electrical connection.

Preferably, the ground pad 1 and the through hole 11 have a plurality of sizes, respectively, and the through holes 11 with different sizes are designed according to the ground pad 1 with different sizes so as to be compatible with the performance of the ground pad 1 and completely remove residual gas. Preferably, when the size of the ground pad 1 is smaller than 4mm by 4mm, the ground pad 1 is not provided with the through hole 11; when the size of the grounding pad 1 is between 4mm and 8mm, the grounding pad 1 is provided with a through hole 11 with the diameter of 0.6 mm; when the size of the grounding pad 1 is larger than 8mm by 8mm, the grounding pad 1 is provided with a through hole 11 with the diameter of 0.8 mm. Preferably, the through hole 11 is a circular cylindrical hole for connecting a plurality of electrical layers of the PCB board 100.

According to the PCB 100 for preventing the secondary reflow soldering paster of the module chip from flying, the through holes 11 with different radiuses are arranged according to the size of the grounding pad 1, so that the compatibility with the performance of the grounding pad 1 is facilitated, and the material of the PCB 100 is saved; when the module chip 2 is subjected to reflow soldering, the PCB 100 and the module chip 2 are subjected to diffusion, overflow or reflow mixing by the coated solder paste, and residual gas in a through hole which is not filled with oil on the PCB 100 is discharged through the through hole 11, so that the grounding pad 1 is completely adhered to the PCB 100, the poor quality of the PCB 100 caused by the residual gas under the module chip 2 during secondary furnace passing is effectively prevented, and a product is effectively protected; the PCB 100 for preventing the flying of the module chip secondary reflow soldering patches is widely used for products similar to QFN packages having ground pads with larger sizes and requiring secondary reflow.

It should be noted that the present invention is not limited to the above embodiments, and other changes can be made by those skilled in the art according to the spirit of the present invention, and all the changes made according to the spirit of the present invention should be included in the scope of the present invention.

Claims

1. The PCB is characterized in that a through hole is formed in the grounding pad, and the PCB is brushed with solder paste to move when the module chip is subjected to reflow soldering so as to push gas to move to the through hole and discharge the gas through the through hole.

2. The PCB of claim 1, wherein the through holes have a plurality of sizes, and different sizes of through holes are designed according to different sizes of the ground pads, so as to be compatible with the performance of the ground pads with different sizes and completely remove residual gas.

3. The PCB for preventing the flying of the secondary reflow soldering patches of the module chip as claimed in claim 1, wherein the PCB has a plurality of electrical layers, the through holes are used for connecting the plurality of electrical layers of the PCB, and the through holes are cylindrical holes.

4. The PCB of claim 1, wherein the ground pad has no through hole when the size of the ground pad is less than 4mm by 4 mm; when the size of the grounding pad is between 4mm and 4mm to 8mm, the grounding pad is provided with a through hole with the diameter of 0.6 mm; when the size of the grounding pad is larger than 8mm by 8mm, the grounding pad is provided with a through hole with the diameter of 0.8 mm.