CN202285232U

CN202285232U - Printed circuit board (PCB) radiating pad structure for quad flat no lead (QFN) encapsulated component

Info

Publication number: CN202285232U
Application number: CN2011203712298U
Authority: CN
Inventors: 熊健劲
Original assignee: Huizhou TCL Mobile Communication Co Ltd
Current assignee: Huizhou TCL Mobile Communication Co Ltd
Priority date: 2011-09-27
Filing date: 2011-09-27
Publication date: 2012-06-27
Anticipated expiration: 2021-09-27

Abstract

The utility model provides a printed circuit board (PCB) radiating pad structure for a quad flat no lead (QFN) encapsulated component. A criss-cross green oil solder mask layer is arranged on a radiating pad and divides the radiating pad into four evenly distributed welding areas, buried holes are arranged in a PCB substrate below the four evenly distributed welding areas, and a plurality of radiating holes are arranged below the criss-cross green oil solder mask layer. The PCB radiating pad structure for the QFN encapsulated component solves problems of reduction in welding reliability in the prior art caused by the fact that tin paste is apt to leak into the radiating holes, and improves thermal performance, electric performance and welding spot reliability.

Description

A kind of PCB heat radiation pad structure that is used for the QFN potted element

Technical field

The utility model relates to the encapsulation technology field of printed circuit board (PCB), relates in particular to a kind of PCB heat radiation pad structure of the QFN of being used for potted element.

Background technology

Along with the continuous development of electronic design technology, the microminiaturization of electronic devices and components, integrated circuit integrated; Caused components and parts and component heat current density to improve constantly; Research shows that most of electronic devices and components generation faults are that design is bad in the electronic equipment, and the internal heat Cycle Difference raises the components and parts temperature; And because the indoor design problem, also make components and parts occur easily squinting and lack the problem of tin.

In the prior art, QFN (Quad Flat No Lead, four sides do not have the pin flat packaging) is a kind of new relatively IC packing forms; Because its special advantages, its application is increased fast, and the QFN outward appearance is square or rectangle; Very thin very light, its element bottom has the weldering end with the bottom surface level, has a large tracts of land heat radiation pad to be used for heat conduction in central authorities; Some louvres that on the heat radiation pad, distribute uniformly then are because louvre is many on the heat radiation pad, during welding; Tin cream drains to the louvre the inside easily, has caused the welding reliability reduction.

There is defective in the prior art practical application, so have much room for improvement.

The utility model content

The purpose of the utility model is, the defective that exists to above-mentioned prior art provides a kind of PCB heat radiation pad structure of the QFN of being used for potted element, has solved the low problem of existing soldering reliability in the prior art.

The technical scheme of the utility model is following: a kind of PCB heat radiation pad structure that is used for the QFN potted element; Comprise the PCB substrate; The heat radiation pad; Said heat radiation pad is positioned at the outer surface of said PCB substrate, it is characterized in that: said heat radiation pad is provided with the green oil solder mask that is cross-shaped, and said green oil solder mask is divided into a plurality of welding regions with said heat radiation pad; Said heat radiation pad be distributed with some louvres and with said PCB substrate on the corresponding one by one setting of blind hole, said louvre is covered by said green oil solder mask.

Wherein, said heat radiation pad is evenly divided into the welding region of matrix pattern.

Wherein, below each welding region with respect to said heat radiation pad on the said PCB substrate, have some equally distributed buried via holes, each welding region below has 5 buried via holes.

Wherein, said louvre is evenly distributed successively along said cross-shaped green oil solder mask below, the said cross-shaped rectangular strip of the horizontal and vertical difference of green oil solder mask.

Wherein, said louvre is rounded.

Wherein, said blind hole is connected to the ground plane of said PCB substrate internal layer, is communicated to through said buried via hole on the main ground plane of said PCB substrate internal layer.

The beneficial effect of the utility model is: the utility model since louvre be distributed in successively the heat radiation pad cross green oil solder mask below; Louvre concentrates on the non-tin zone (being cross green oil solder mask) of going up of pad; When welding, can avoid tin cream to drain in the louvre, improve the reliability of solder joint; And have blind hole and buried via hole on the PCB substrate, blind hole is communicated on the main ground plane of PCB substrate internal layer through buried via hole, has realized grounding function, and its hot property, electrical property and welding spot reliability all have greatly improved.

Description of drawings

Fig. 1 is the utility model heat radiation pad green oil solder mask sketch map.

Fig. 2 is the utility model PCB heat radiation pad structure blind hole sketch map.

Fig. 3 is the utility model PCB heat radiation pad structure buried via hole sketch map.

Embodiment

The utility model provides a kind of PCB heat radiation pad structure of the QFN of being used for potted element; Be used for cell phone mainboard; Be cross-shaped green oil solder mask through on the heat radiation pad, being provided with, the green oil solder mask pad that will dispel the heat is divided into four equally distributed welding regions, has buried via hole in the PCB substrate under four equally distributed welding regions; And below being cross-shaped green oil solder mask, have some louvres; The tin cream that has overcome the prior art existence drains in the louvre easily, and the problem that has caused welding reliability to reduce has improved its hot property, electrical property and welding spot reliability.

For the purpose, technical scheme and the advantage that make the utility model is clearer, clear and definite, below develop simultaneously embodiment to the utility model further explain with reference to accompanying drawing.Fig. 1 is the utility model heat radiation pad green oil solder mask sketch map, and as shown in Figure 1, PCB heat radiation pad structure comprises PCB substrate 100 and is positioned at the heat radiation pad 200 on PCB substrate 100 outer surfaces; Also have one on the heat radiation pad 200 and be cross-shaped green oil solder mask 201; The cross-shaped rectangular strip of green oil solder mask 201 horizontal and vertical difference is divided into the welding region 202 of matrix pattern through green oil solder mask 201 pad that will dispel the heat, and the area of each welding region is identical; Certainly be not so limited; Can be divided into other shape, the welding region 202 of matrix pattern is for the ease of evenly going up tin, improving the reliable welding degree.

Fig. 2 is the blind hole structure sketch map of the utility model PCB heat radiation pad green oil solder mask below; As shown in Figure 2; Have some louvres 203 on the heat radiation pad 200 of PCB heat radiation pad structure; Simultaneously have the identical blind hole of shape quantity and louvre 203 with louvre 203 corresponding positions on the PCB substrate 100, louvre 203 is by the covering of green oil solder mask, and blind hole is got to ground plane; Louvre 203 is evenly distributed successively along cross-shaped green oil solder mask below; The shape of louvre 203 is circular; The diameter of louvre 203 is less than the width of rectangle strip (being the green oil solder mask); Louvre 203 is distributed in successively below the cross green oil solder mask of heat radiation pad, louvre concentrates on the non-tin regional (being cross green oil solder mask) of going up of pad like this, avoids tin cream to drain in the louvre.

Fig. 3 is the buried via hole structural representation of the utility model PCB heat radiation pad welding region below; Cell phone mainboard is multi-layer sheet (not showing multi-layer sheet among the figure); Heat radiation pad 200 inner surfaces of PCB heat radiation pad structure link to each other with PCB substrate 100 outer surfaces;, heat radiation pad 200 is evenly distributed with a plurality of buried via holes 110 (be the interior layer of PCB substrate 100, that is to say that buried via hole 110 is to be embedded in plank inside) below being each welding region 202 of matrix pattern, according to 5 buried via holes that evenly distributed below each welding region 202 of Fig. 3; (blind hole passes to the internal grounded layers of PCB substrate 100 through blind hole; Form the zone network of heat radiation pad, zone network is exactly all ground connection of each louvre, after with each the louvre ground connection on one deck, forms a zone network) be connected to the ground plane of PCB substrate internal layer; Be communicated to (mainly just) on the main ground plane of PCB substrate internal layer through buried via hole again, this structure Design helps heat radiation and strengthens electrical connectivity.

What should explain is; Above embodiment is only unrestricted in order to the technical scheme of explanation the utility model; Although with reference to preferred embodiment the utility model is specified, those of ordinary skill in the art should be appreciated that and can make amendment or be equal to replacement the technical scheme of the utility model; And not breaking away from the spirit and the scope of the utility model technical scheme, it all should be encompassed in the middle of the claim scope of the utility model.

Claims

1. PCB heat radiation pad structure that is used for the QFN potted element; Comprise the PCB substrate, the heat radiation pad, said heat radiation pad is positioned at the outer surface of said PCB substrate; It is characterized in that: said heat radiation pad is provided with the green oil solder mask that is cross-shaped; Said green oil solder mask is divided into a plurality of welding regions with said heat radiation pad, said heat radiation pad be distributed with some louvres and with said PCB substrate on the corresponding one by one setting of blind hole, said louvre is covered by said green oil solder mask.

2. heat radiation pad structure according to claim 1 is characterized in that said heat radiation pad is evenly divided into the welding region of matrix pattern.

3. heat radiation pad structure according to claim 2 is characterized in that, below each welding region with respect to said heat radiation pad on the said PCB substrate, has some equally distributed buried via holes.

4. heat radiation pad structure according to claim 3 is characterized in that, each welding region below has 5 buried via holes.

5. heat radiation pad structure according to claim 1 is characterized in that, said louvre is evenly distributed successively along said cross-shaped green oil solder mask below, the said cross-shaped rectangular strip of the horizontal and vertical difference of green oil solder mask.

6. heat radiation pad structure according to claim 1 is characterized in that said louvre is rounded.

7. according to claim 3 or 5 described heat radiation pad structures, it is characterized in that said blind hole is connected to the ground plane of said PCB substrate internal layer, said ground plane is communicated on the main ground plane of said PCB substrate internal layer through said buried via hole.