Lead frame for chip positioning in LFPAK packaging

Abstract

The utility model relates to the lead frame field, and discloses a lead frame used for chip positioning in LFPAK packaging, comprising a lead frame plate, the upper end surface of the lead frame plate is downwardly penetrated to form a positioning hole, the upper end surface of the lead frame plate sinks to form a placing groove, the placing groove is arranged above the positioning hole, and the positioning hole is arranged on the upper end surface of the lead frame plate. A positioning hole is formed in the lead frame plate, a placement plate is integrally formed at the bottom end of the lead frame plate, the upper surface of the placement plate is flush with the bottom end of the positioning hole, a chip is placed in the positioning hole, a copper sheet clamp is arranged above the chip, and the positioning hole and the placement groove which are matched with the chip and the copper sheet clamp respectively are formed in the lead frame. According to the lead frame, the chip and the copper sheet clamp can be placed in the positioning hole and the placement groove, so that the chip and the copper sheet clamp can be quickly positioned and fixed, subsequent packaging is facilitated, the precision is improved, the placement plate is arranged below the lead frame plate, the chip can be supported and placed, the placement plate is thin and small in size, and the weight and the size of the whole lead frame are reduced.

Description

Technical Field

[0001] The utility model relates to the field of lead frames, in particular to a lead frame used for chip positioning in LFPAK packaging. Background Art

[0002] When the chip is manufactured, it needs to be placed on the lead frame and packaged. In the LFPAK package, the chip is usually placed on the lead frame, and then a copper clip is placed on the top of the chip. After plastic sealing, a semiconductor product in the form of LFPAK package is obtained. At present, the chip and the copper clip are generally placed directly on the lead frame and transported to the corresponding equipment for plastic sealing. Since there is no corresponding positioning and fixing structure on the lead frame, the position may be offset during the movement, resulting in a decrease in accuracy. To this end, we designed a lead frame for chip positioning in the LFPAK package. Utility Model Content

[0003] In order to solve the technical problem of quickly positioning a chip and a copper sheet clip without displacement, the utility model provides a lead frame for chip positioning in an LFPAK package.

[0004] The utility model is implemented by the following technical scheme: a lead frame for chip positioning in an LFPAK package, comprising a lead frame plate, the upper surface of the lead frame plate is penetrated downward to form a positioning hole, and the upper surface of the lead frame plate is sunken to form a placement groove, the placement groove is above the positioning hole, the bottom end of the lead frame plate is integrally formed with a placement plate, the upper surface of the placement plate is flush with the bottom end of the positioning hole, a chip is placed in the positioning hole, a copper sheet clip is arranged above the chip, and the copper sheet clip is placed in the placement groove.

[0005] As a further improvement of the above solution, the size of the placement plate is larger than the size of the positioning hole, and the thickness of the placement plate is 1-3MM, which is convenient for the placement plate to be set under the lead frame plate, thereby facilitating the placement and fixation of the chip.

[0006] As a further improvement of the above scheme, the front end of the placement plate is integrally formed with three equally spaced positioning blocks, the positioning blocks are welded with connecting pins, and the bottom end surfaces of the connecting pins are flush with the lower surface of the placement plate. The connecting pins are used to connect to the circuits of the circuit board, and the bottoms of the connecting pins are flush with the bottom of the placement plate, which also facilitates the installation of the lead frame and ensures the horizontality.

[0007] As a further improvement of the above scheme, the upper surface of the positioning block is recessed downward to form an embedding groove, and the upper end of the connecting pin is embedded in the embedding groove and welded, which can quickly fix the connecting pin on the positioning block and make it less likely to shift in position, facilitate subsequent welding, and improve accuracy.

[0008] As a further improvement of the above scheme, a support pad is integrally formed at the four corners of the lower end surface of the lead frame plate, and the bottom end surface of the support pad is coplanar with the bottom end surface of the connecting pin and the placement plate, thereby ensuring the stability of the lead frame plate around the bottom, being able to support it, and ensuring the horizontality of the lead frame. At the same time, the lower part of the lead frame is designed to be suspended, and the bottom end of the lead frame has a certain spacing after being packaged, which is convenient for the circulation of airflow, thereby improving the heat dissipation effect, and the entire lead frame is thin and light.

[0009] As a further improvement of the above scheme, the lead frame plate, placement plate, positioning block and four support pads are all designed in an integrated manner, and the outer surfaces of the lead frame plate, placement plate, positioning block and support pads are all electroplated, and their surfaces are all silver-plated and nickel-plated. The thickness of the silver plating is 1.5-5.0um, and the thickness of the nickel plating is 1.3-5.0um. The lead frame plate, placement plate, positioning block and four support pads are all made of copper material, and the hardness of the copper material is HV130-150.

[0010] Compared with the prior art, the beneficial effects of the present invention are:

[0011] 1. The utility model provides positioning holes and placement grooves on the lead frame that match the chip and the copper clip respectively. The chip and the copper clip can be placed in the positioning holes and placement grooves, and can be quickly positioned and fixed, which is convenient for subsequent packaging and improves accuracy;

[0012] 2. By setting a placement plate under the lead frame, the chip can be supported and placed, and the placement plate is thin and small in size, which reduces the weight and size of the entire lead frame. The design of the support pad allows the bottom end of the lead frame to have a certain distance after packaging, which facilitates the circulation of airflow and improves the heat dissipation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A schematic diagram of the overall structure of a lead frame for chip positioning in an LFPAK package provided by the utility model;

[0014] Figure 2 for Figure 1 Bottom schematic diagram of ;

[0015] Figure 3 for Figure 1 Schematic diagram of the structure in which the chip and copper sheet clip are arranged.

[0016] Description of main symbols:

[0017] 1. Lead frame plate; 11. Placement groove; 12. Positioning hole; 2. Placement plate; 3. Positioning block; 4. Connecting pins; 5. Support pad; 6. Chip; 7. Copper sheet clip. DETAILED DESCRIPTION

[0018] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form a new embodiment.

[0019] Example:

[0020] Please combine Figure 1-Figure 3 A lead frame for chip positioning in an LFPAK package of the present embodiment includes a lead frame plate 1, characterized in that a positioning hole 12 is formed downwardly through the upper surface of the lead frame plate 1, and a placement groove 11 is formed downwardly on the upper surface of the lead frame plate 1, and the placement groove 11 is located above the positioning hole 12. A placement plate 2 is integrally formed at the bottom end of the lead frame plate 1, and the upper surface of the placement plate 2 is flush with the bottom end of the positioning hole 12. A chip 6 is placed in the positioning hole 12, and a copper sheet clip 7 is arranged above the chip 6, and the copper sheet clip 7 is placed in the placement groove 11.

[0021] The size of the placement plate 2 is larger than the size of the positioning hole 12 , and the thickness of the placement plate 2 is 1-3MM, which is convenient for the placement plate 2 to be arranged below the lead frame plate 1 , thereby facilitating the placement and fixation of the chip 6 .

[0022] The front end of the placement plate 2 is integrally formed with three equally spaced positioning blocks 3, on which connecting pins 4 are welded, and the bottom surface of the connecting pins 4 is flush with the lower surface of the placement plate 2. The connecting pins 4 are used to connect to the circuit board's circuit board, and the bottom of the connecting pins 4 is flush with the bottom of the placement plate 2, which also facilitates the installation of the lead frame and ensures the horizontality.

[0023] The upper surface of the positioning block 3 is recessed downward to form an embedding groove, and the upper end of the connecting pin 4 is embedded in the embedding groove and welded, which can quickly fix the connecting pin 4 on the positioning block 3 and make it less likely to shift in position, facilitate subsequent welding, and improve accuracy.

[0024] A support pad 5 is integrally formed at each of the four corners of the lower surface of the lead frame plate 1. The bottom surface of the support pad 5 is coplanar with the bottom surface of the connecting pin 4 and the placement plate 2, ensuring the stability of the lead frame plate 1 around the bottom, supporting it, and ensuring the horizontality of the lead frame. At the same time, the lower part of the lead frame is suspended, and the bottom end of the lead frame has a certain distance after packaging, which is convenient for the circulation of airflow, thereby improving the heat dissipation effect, and the thickness of the entire lead frame is thin and the weight is light.

[0025] The lead frame plate 1, the placement plate 2, the positioning block 3 and the four support pads 5 are all designed in an integrated manner, and the outer surfaces of the lead frame plate 1, the placement plate 2, the positioning block 3 and the support pad 5 are all electroplated, and the surfaces are all silver-plated and nickel-plated. The thickness of the silver plating is 1.5-5.0um, and the thickness of the nickel plating is 1.3-5.0um. The lead frame plate 1, the placement plate 2, the positioning block 3 and the four support pads 5 are all made of copper material, and the hardness of the copper material is HV130-150.

[0026] The implementation principle of a lead frame for chip positioning in an LFPAK package in an embodiment of the present application is as follows: in actual use, the chip 6 is placed above the lead placement plate 2 and in the positioning hole 12. The size and shape of the positioning hole 12 match the size and shape of the chip 6, so that the chip 6 can be directly positioned and fixed accordingly. Then, the copper sheet clip 7 is placed above the chip 6, and the copper sheet clip 7 is in the placement groove 11. The shape and size of the placement groove 11 match the shape and size of the copper sheet clip 7, so that the copper sheet clip 7 can be positioned and fixed. Then, the corresponding packaging can be performed to obtain a semiconductor product in the form of an LFPAK package after plastic sealing.

[0027] By providing positioning holes 12 and placement grooves 11 respectively matching the chip 6 and the copper sheet clip 7 on the lead frame, the chip 6 and the copper sheet clip 7 can be placed in the positioning holes 12 and the placement grooves 11, and then can be quickly positioned and fixed, which is convenient for subsequent packaging and improves the accuracy;

[0028] By setting a placement plate 2 under the lead frame plate 1, the chip 6 can be supported and placed, and the placement plate 2 is thin and small in size, which reduces the weight and size of the entire lead frame. The design of the support pad 5 allows a certain spacing at the bottom of the lead frame after packaging, which facilitates the circulation of airflow and thereby improves the heat dissipation effect.

[0029] The above-mentioned implementation modes are only preferred implementation modes of the present invention, and cannot be used to limit the protection scope of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A lead frame for chip positioning in an LFPAK package, comprising a lead frame plate (1), characterized in that: The upper surface of the lead frame plate (1) is penetrated downward to form a positioning hole (12), and the upper surface of the lead frame plate (1) is sunken to form a placement groove (11), the placement groove (11) is located above the positioning hole (12), the bottom of the lead frame plate (1) is integrally formed with a placement plate (2), the upper surface of the placement plate (2) is flush with the bottom of the positioning hole (12), a chip (6) is placed in the positioning hole (12), a copper sheet clip (7) is arranged above the chip (6), and the copper sheet clip (7) is placed in the placement groove (11).

2. A lead frame for chip positioning in an LFPAK package as claimed in claim 1, characterized in that: The size of the placement plate (2) is larger than the size of the positioning hole (12), and the thickness of the placement plate (2) is 1-3MM.

3. A lead frame for chip positioning in an LFPAK package as claimed in claim 1, characterized in that: The front end of the placement plate (2) is integrally formed with three positioning blocks (3) distributed at equal intervals, and connecting pins (4) are welded on the positioning blocks (3), and the bottom end surfaces of the connecting pins (4) are flush with the lower surface of the placement plate (2).

4. A lead frame for chip positioning in an LFPAK package as claimed in claim 3, characterized in that: The upper end surface of the positioning block (3) is recessed downward to form an embedding groove, and the upper end of the connecting pin (4) is embedded in the embedding groove and welded.

5. A lead frame for chip positioning in an LFPAK package as claimed in claim 1, characterized in that: A support pad (5) is integrally formed at each of the four corners of the lower end surface of the lead frame plate (1), and the bottom end surface of the support pad (5) is coplanar with the bottom end surface of the connecting pin (4) and the placement plate (2).

6. A lead frame for chip positioning in an LFPAK package as claimed in claim 4, characterized in that: The lead frame plate (1), the placement plate (2), the positioning block (3) and the four support pads (5) are all designed as an integrated whole, and the external surfaces of the lead frame plate (1), the placement plate (2), the positioning block (3) and the support pads (5) are all designed to be electroplated, and the surfaces are all silver-plated and nickel-plated.

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