CN211404492U - Visual angle lead frame structure with circuit tin absorption - Google Patents

Abstract

The utility model discloses a utensil circuit tin-absorbing visual angle lead frame structure, include: a lead frame, a platform and a circuit layer. The lead frame has a metal frame, a plurality of connecting rods, a chip seat and a plurality of through areas. The platform is arranged on the lead frame, a groove is respectively arranged on the peripheral edge of the back surface of the platform, a plurality of grooves and through holes are respectively arranged on the front surface and the back surface of the platform, the grooves are respectively provided with an outer end part and an inner end part, the grooves on the back surface extend on the groove, and the inner end parts of the grooves on the back surface and the outer end parts form a drop height. The circuit layer is arranged in the grooves and the through holes. When the circuit layer on the back of the platform is electrically connected with the circuit board, the inner end parts and the outer end parts of the grooves on the back enable the circuit layer to form a visual angle tin-climbing drop height.

Description

Lead frame structure with line eating tin and viewing angle

technical field

The utility model relates to a lead frame structure, in particular to a lead frame structure when the lead frame structure is welded on a circuit board, the lead frame structure provides the effect of solder climbing, and also forms a tin-eating and viewing angle structure.

Background technique

It is known that a lead frame 100 (as shown in FIGS. 1 a and 1 b ) is firstly fabricated in the current IC semiconductor chip packaging process. The penetrating regions 104 are formed after the connecting rods 102 are connected to the metal frame 101 and the die pad 103 , and the penetrating regions 104 include a first penetrating region 1041 , a second penetrating region 1042 , a A third through region 1043 and a fourth through region 1044 . Next, a platform 200 is formed by molding plastic on the lead frame 100 by means of injection or hot pressing technology. The third through region 1043 and the fourth through region 144 are exposed, only the back surface of the die pad 103 is exposed on the back of the platform 200 , and a plurality of grooves 201 are formed on the front and back of the platform 200 by a laser engraving machine. Finally, the circuit layers 300 are formed in the trenches 201 by using a deposition technique to complete the fabrication of the lead frame structure.

When the lead frame structure is in use, the circuit layer 300 on the back allows the lead frame structure to be soldered on a circuit board (not shown in the figure) by using surface adhesion technology. After soldering, the inspector must pick up the circuit board with a visual Check whether there is a creeping effect between the circuit board and the circuit layer 300 of the lead frame structure. Since the edge of the platform of the traditional lead frame structure is not designed with a space for tin climbing and a viewing angle for inspection by the inspector, the adhesion between the lead frame structure and the circuit board is not good, and it also causes the production Many inconveniences.

Utility model content

Therefore, the main purpose of the present utility model is to solve the traditional deficiency. The present utility model adds a tin-climbing structural design to the lead frame structure. The tin-climbing structural design can be used for soldering and has space for tin-climbing during welding. After completion, the inspector can pick up the circuit board to visually inspect whether there is a tin creeping effect between the lead frame structure and the circuit board, which makes the manufacturing easier and improves the manufacturing yield.

In order to achieve the above-mentioned purpose, the present invention provides a lead frame structure with a line tin and a viewing angle, which is welded on a circuit board and includes a lead frame, a platform and a circuit layer. The lead frame is provided with a metal frame, a plurality of connecting rods, a chip holder and a plurality of penetrating regions. The platform is set on the lead frame, so that the front surface of the platform is exposed from the through areas, and only the back surface of the chip seat is exposed on the back surface, and a groove is provided on each of the peripheral edges of the back surface of the platform; A plurality of grooves are respectively provided, and each of the grooves has a through hole, so that the front surface and the back surface are communicated with the grooves; and the grooves on the front surface and the back surface of the platform are respectively provided with an outer end and an inner end, the grooves on the back of the platform extend on the groove, so that the inner end of the grooves on the back and the outer end form a drop height. The circuit layer is disposed in the trenches and the through holes. Wherein, when the circuit layer on the backside of the platform is electrically connected to the circuit board, the inner end and the outer end of the grooves on the backside make the circuit layer electrically connected to the circuit board form a viewing angle of tin creepage. Drop height.

In an embodiment of the present invention, the lead frame is made of copper metal.

In an embodiment of the present invention, the platform is made of plastic material.

In an embodiment of the present invention, the plastic is an epoxy resin encapsulation material.

In an embodiment of the present invention, the circuit layer has a plurality of conductive pins, a plurality of conductive portions and a plurality of bonding pad portions.

In an embodiment of the present invention, the conductive parts are located in the through holes, one end of the conductive parts is electrically connected to the conductive pins on the front surface of the platform, and the other end of the conductive parts is connected to the back surface of the platform The pads are electrically connected.

In an embodiment of the present invention, the penetration areas include a first penetration area, a second penetration area, a third penetration area, and a fourth penetration area.

In an embodiment of the present invention, the connecting rods are connected with the metal frame and the chip holder to form the through areas, and the through areas are located on four sides of the chip holder.

The present utility model will be described in detail below in conjunction with the accompanying drawings and specific embodiments, but it is not intended to limit the present utility model.

Description of drawings

Figure 1a is a schematic diagram of the appearance of a traditional lead frame structure;

Fig. 1b is a partial enlarged schematic diagram of Fig. 1a;

2 is a schematic view of the appearance of the lead frame of the lead frame structure of the present invention;

Fig. 3 is the back schematic diagram of Fig. 2;

4 is a schematic front view of the lead frame structure forming platform of the present invention;

Fig. 5 is the back schematic diagram of Fig. 4;

6 is a schematic diagram of making grooves and through holes on the front surface of the platform of the present invention;

FIG. 7 is a schematic diagram of the backside of FIG. 6 making grooves;

8 is a schematic diagram of the groove and through-hole fabrication circuit on the platform of the present invention;

Fig. 9 is the back schematic diagram of Fig. 8;

Fig. 10 is a schematic side sectional view of Fig. 8;

11 is a schematic diagram of the lead frame structure and circuit board welding of the present invention.

Among them, reference numerals:

100 Lead Frame

101 Metal Frame

102 Coupling rod

103 Chip holder

104 Penetration area

1041 The first penetration area

1042 Second penetration area

1043 Third penetration area

1044 Fourth penetration area

200 platforms

201 Groove

300 line layers

10 Lead frame structure

1 Lead frame

11 Metal frame

12 Coupling rod

13 Chip holder

14 through the area

141 The first penetration area

142 Second penetration area

143 Third penetration area

144 Fourth Penetration Area

2 platforms

21 grooves

22 grooves

221 Outer end

222 inner end

23 Through hole

3 circuit layers

31 Conductive pins

32 Conductive part

33 Pads

4 circuit boards

Detailed ways

Hereby, the technical content and detailed description of the present utility model are described as follows in conjunction with the drawings:

Please refer to FIG. 2 and FIG. 3 , which are the appearance of the lead frame of the lead frame structure of the present invention and the schematic diagram of the back of FIG. 2 . As shown in the figure: In the lead frame structure of the present invention, a lead frame structure 10 is formed by stamping a metal plate. The lead frame structure 10 has a lead frame 1, and the lead frame 1 has a lead frame structure 10. A metal frame 11 , a plurality of tie bars 12 , a chip holder 13 and a plurality of through regions 14 , the tie bars 12 are connected with the metal frame 11 and the chip seat 13 to form the through regions 14 , the The penetration area 14 includes a first penetration area 141 , a second penetration area 142 , a third penetration area 143 and a fourth penetration area 144 . In this figure, the lead frame structure 1 is made of copper metal.

Please refer to FIG. 4 and FIG. 5 , which are schematic views of the front side and the back side of FIG. 4 of the lead frame structure forming platform of the present invention. As shown in the figure: a platform 2 is formed by molding plastic on the lead frame 1 using injection or hot pressing technology on the lead frame 1 that has been fabricated above. The penetration area 141 , the second penetration area 142 , the third penetration area 143 , and the fourth penetration area 144 are exposed, and only the back surface of the chip holder 13 is exposed on the back of the platform 2 , and each of the surrounding edges of the back surface of the platform 2 is exposed. There is a groove 21, and the groove 21 and the back of the platform 2 are formed with a space for tin climbing during soldering, so as to improve the adhesion of the lead frame structure 10 to the circuit board (shown in the figure). In this figure, the plastic is epoxy molding compound (Epoxy Molding Compound, EMC).

Please refer to FIGS. 6 and 7 , which are schematic diagrams of making grooves and through holes on the front of the platform of the present invention and making grooves on the back of FIG. 6 . As shown in the figure: after the platform 2 is formed, use a laser engraving machine (not shown in the figure) to carry out photo-etching on the front and back of the platform 2, and after photo-etching, the front and back of the platform 2 are respectively A plurality of grooves 22 are formed, and the grooves 22 have an outer end 221 and an inner end 222. The grooves 22 on the back of the platform 2 extend on the grooves 21, so that the grooves on the back The inner end 222 of the groove 22 and the outer end 221 form a drop height, and the drop height provides the viewing angle of the solder climbing and tin eating. Furthermore, through holes 23 are respectively provided on the grooves 22 , and the through holes 23 penetrate through the front and back surfaces of the platform 2 , so that the grooves 22 on the front and back surfaces of the platform 2 communicate with each other.

Please refer to FIG. 8 , FIG. 9 , and FIG. 10 , which are schematic diagrams of the grooves and through-hole fabrication circuits on the platform of the present invention, the back surface of FIG. 8 and the side cross-sectional views of FIG. 8 . As shown in the figure: after the above-mentioned grooves 22 and the through holes 23 of the platform 2 are fabricated, a thin film deposition technique is performed in the grooves 22 and the through holes 23. Metal material is deposited in the trenches 22 and the through holes 33 to form a circuit layer 3 . The circuit layer 3 includes a plurality of conductive pins 31 , a plurality of conductive portions 32 and a plurality of pad portions 33 . The conductive parts 32 are located in the through holes 22 , one end of the conductive parts 32 is electrically connected with the conductive pins 31 on the front surface of the platform 2 , and one end of the conductive parts 32 is connected with the solder joints on the back of the platform 2 . The pad portion 33 is electrically connected. And the pads 33 in the grooves 22 on the back of the platform 2 extend into the grooves 21 .

Please refer to FIG. 11 , which is a schematic diagram of the lead frame structure and circuit board welding of the present invention. as the picture shows. When the lead frame structure 10 of the present invention is fabricated, the metal frame 11 of the lead frame 1 is cut after the lead frame structure 10 is processed such as die bonding, wire bonding, and packaging.

When the cut lead frame structure 10 is welded to the pads 41 of the circuit board 4 , the flux contained in the solder 5 will move to a place with a high temperature during the soldering process, and the solder 5 will follow The back head also moves to the place where the temperature is high to the solder pads 33 in the groove 21 , and the effect of this creeping tin can improve the adhesion for surface mount (SMD) technology.

At the same time, after the soldering is completed, the height of the drop formed between the inner end portion 222 of the grooves 22 and the outer end portion 221 allows the operator to pick up the circuit board 4 for visual inspection. The drop height between the inner end portions 222 of the grooves 22 and the outer end portion 221 can be used to see whether the solder pad portions 33 have a tin creeping effect, so as to increase the convenience of inspection by the operator.

However, the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the scope of patent protection of the present invention.

Of course, the present utility model can also have other various embodiments, without departing from the spirit and essence of the present utility model, those skilled in the art can make various corresponding changes and deformations according to the present utility model, but these Corresponding changes and deformations shall belong to the protection scope of the claims of the present invention.

Claims (8)

1. A kind of structure of visual angle lead frame with tin-absorbing circuit, weld on the circuit board, characterized by that, including:

a lead frame, which is provided with a metal frame, a plurality of connecting rods, a chip seat and a plurality of through areas;

a platform on the lead frame, the front of the platform is exposed from the through area, the back only exposes the back of the chip base, and there are grooves on the peripheral edge of the back of the platform, there are several grooves on the front and back of the platform, there are through holes in the grooves, the grooves on the front and back of the platform are communicated with each other, there are an outer end and an inner end on the grooves, the grooves on the back of the platform extend on the grooves, the inner end and the outer end of the groove on the back form a height, the through holes are set on the grooves, the through holes are set on

The circuit layer is arranged in the groove and the through hole;

when the circuit layer on the back of the platform is electrically connected with the circuit board, the inner end part and the outer end part of the groove on the back enable the circuit layer electrically connected with the circuit board to form a tin-climbing visual angle drop height.

2. The leadframe structure with wire wicking visibility angle of claim 1, wherein the leadframe is copper metal.

3. The leadframe structure with solder bump viewing angle of claim 1, wherein the pad is made of plastic.

4. The leadframe structure with solder mask according to claim 3, wherein the plastic is epoxy encapsulation material.

5. The leadframe structure with tinning viewing angle of claim 1, wherein the circuit layer has a plurality of conductive pins, a plurality of conductive portions and a plurality of pad portions.

6. The leadframe structure of claim 5, wherein the conductive portion is disposed in the through hole, one end of the conductive portion is electrically connected to the conductive pin on the front side of the platform, and the other end of the conductive portion is electrically connected to the pad portion on the back side of the platform.

7. The leadframe structure of claim 1, wherein the through region comprises a first through region, a second through region, a third through region and a fourth through region.

8. The leadframe structure of claim 1, wherein the tie bar is bonded to the metal frame and the die pad to form the through areas, and the through areas are located on four sides of the die pad.

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