Reinforced upper heat dissipating lead frame array

Abstract

This utility model discloses a reinforced upper heat dissipation lead frame array, relating to the field of semiconductor manufacturing technology. It includes a strip body with two rows of lead frames arranged opposite each other. Two lead frames in the same row form a group. Within the same group, the substrates of the two lead frames, the inner ends of the leads of the two lead frames, and the inner ends of the heat dissipation ribs on the substrates of the two lead frames are all disconnected. Connecting ribs are provided between adjacent groups of lead frames. The two sides of the connecting ribs are spaced apart from the lead frames, and one end of the connecting rib connects to the lead of the lead frame, while the other end connects to the heat dissipation rib of the lead frame. Both ends of the connecting rib have inclined sections and elongated holes, with the inclined sections located between the two ends of the elongated holes. This utility model not only prevents lead displacement during subsequent slitting due to deformation of the inclined sections, but also ensures that the lead frame strips are stacked flat during slitting and packaging.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor manufacturing technology, and more specifically, to a reinforced upper heat dissipation lead frame. Background Technology

[0002] Leadframes serve multiple functions, including supporting the chip, connecting internal chips to external circuit boards for electrical signals, and mounting and securing electronic components. Power devices inevitably generate heat dissipation during operation. The accumulation of this internal heat dissipation leads to an increase in the chip's structural temperature; the higher the power density, the higher the internal temperature. Therefore, good heat dissipation performance is crucial for overcoming the thermal bottleneck of power devices and achieving high-power characteristics. In existing technologies, the heat generated during chip operation is transferred downwards through the PCB board and upwards through the molding compound. The low thermal conductivity of the PCB board and molding compound, far inferior to that of metals, results in persistently high device temperatures. Adjusting the device to have a top-mounted heat sink can provide better heat dissipation. Top-heat-dissipated power device leadframes offer excellent heat dissipation, improve power density, and are an essential component in integrated packaging production during semiconductor packaging manufacturing.

[0003] When using a top-heat-dissipating power device leadframe for integrated chip packaging, the chip is mounted onto a substrate, and then the chip is connected to the leadframe pin area using a wire bonding process. Finally, the chip is injection molded in a dedicated mold. After packaging, excess leadframe is cut off to form a single top-heat-dissipating power device packaged product. The formed single product includes a chip encapsulated in packaging material and exposed wiring pins. Therefore, the structure of the leadframe determines the quality and efficiency of chip packaging, which is of great significance to semiconductor packaging companies.

[0004] In existing leadframes, the leads are disconnected from the substrate during stamping. Therefore, to ensure the integrity of the leadframe, a connecting rib is retained between adjacent leadframes in the same row. This connecting rib connects the leads on the leadframe to the heat dissipation ribs on the substrate, preventing the leads from detaching from the substrate. However, existing connecting ribs are typically bent at 120°. This not only makes it difficult to lay the leadframe flat during stacking and packaging, causing the leadframe to tilt, but also, during the cutting of the formed leadframe, the inclined section of the connecting rib causes it to be punched and deformed, leading to displacement of the leads, making it difficult to guarantee the quality of the leadframe. Utility Model Content

[0005] The purpose of this invention is to provide a reinforced upper heat dissipation lead frame array, which not only prevents the lead frame material from shifting due to the deformation of the inclined section during subsequent slitting, but also ensures that the lead frame material can be stacked flat during the slitting and packaging process, facilitating subsequent packaging.

[0006] To achieve the purpose of this utility model, the technical solution adopted is as follows: a reinforced upper heat dissipation lead frame array, comprising a material strip body, on which two rows of lead frames are arranged opposite each other, the heat dissipation horizontal ribs on the two oppositely arranged lead frames are connected together, and the pins on multiple lead frames in the same row are connected together, and the heat dissipation horizontal ribs on multiple lead frames in the same row are connected together; two lead frames in the same row form a group, and the carrier plates of the two lead frames in the same group, the inner ends of the pins of the two lead frames, and the inner ends of the heat dissipation horizontal ribs on the carrier plates of the two lead frames are all disconnected, and there is a connecting rib between adjacent groups of lead frames, with a certain gap between the two sides of the connecting rib and the lead frame, and one end of the connecting rib is connected to the pin of the lead frame, and the other end of the connecting rib is connected to the heat dissipation horizontal rib of the lead frame; both ends of the connecting rib have inclined sections and elongated holes, and the inclined sections are located between the two ends of the elongated holes.

[0007] Furthermore, the tilt angle of the tilted segment is 150°.

[0008] Furthermore, the edge of the back side of the slide plate has a pressing step, and the four sides of the front side of the slide plate have a side step.

[0009] Furthermore, the four edges of the front side of the slide plate have raised ridges.

[0010] Furthermore, the carrier plate has two glue-locking holes on the side near the heat dissipation ribs. The two glue-locking holes are symmetrically arranged on the carrier plate, and the opening edges of the glue-locking holes have upward-protruding steps.

[0011] Furthermore, the carrier plate has three dovetail grooves on the side near the heat dissipation ribs, and the dovetail grooves are on the same straight line as the locking holes.

[0012] Furthermore, the substrate has adhesive grooves on both sides and on the side of the substrate near the pins.

[0013] Furthermore, the pins are provided with side steps on both sides near the end of the substrate.

[0014] The beneficial effects of this utility model are:

[0015] 1. By setting elongated holes on the connecting ribs, the inclined sections of adjacent lead frames do not need to be punched when cutting, thus effectively avoiding deformation of adjacent lead frames during cutting and ensuring the quality of the lead frames.

[0016] 2. By setting the tilt angle of the inclined section to 150°, for a product with a lead frame width of 52.2mm, the copper strip width required for producing the lead frame is only 53.36mm; while with a tilt angle of 120°, the copper strip width required for producing the lead frame of the same 52.2mm width is 54.74mm. That is, for products of the same width, the required raw material width is effectively reduced, and for a lead frame with a width of 52.2mm, the raw material conversion rate is increased by 2.58%.

[0017] 3. By setting pressing steps, side steps, protruding ridges, dovetail grooves, and locking holes with raised openings on the substrate, leakage of molding compound during encapsulation is effectively prevented, the tightness between the substrate and the molding compound is strengthened, and the quality of the encapsulated product is greatly improved. Attached Figure Description

[0018] The accompanying drawings illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the principles of the present invention. These drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification.

[0019] Figure 1 This is a schematic diagram of the reinforced upper heat dissipation lead frame provided by this utility model;

[0020] Figure 2 This is a side view of the reinforced upper heat dissipation lead frame.

[0021] Figure 3 It is a cross-sectional view of the slide plate;

[0022] Figure 4 It is an enlarged view of the pier step, the side step, and the protruding edge;

[0023] Figure 5 This is a schematic diagram of the locking hole;

[0024] Figure 6 This is a partial view of the inner end of the pin;

[0025] Figure 7 This is a schematic diagram of the lead frame after it has been encapsulated.

[0026] The attached diagram shows the markings and corresponding component names:

[0027] 1. Material strip body; 2. Lead wire frame; 3. Connecting rib; 4. Long hole; 5. Material distribution hole;

[0028] 21. Carrier board; 22. Pins; 23. Heat sink ribs;

[0029] 211. Pressing step; 212. Side step one; 213. Raised ridge; 214. Locking hole; 215. Step; 216. Dovetail groove; 217. Locking groove.

[0030] 221. Side Step Two;

[0031] 31. Inclined section. Detailed Implementation

[0032] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present invention are shown in the accompanying drawings.

[0033] It should be noted that, where there is no conflict, the embodiments and features described in these embodiments can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0034] like Figures 1 to 6 As shown, the present invention provides a reinforced upper heat dissipation lead frame array, including a strip body 1, the strip body 1 being a copper strip, and the width of the strip body 1 being greater than the length of the two lead frames 2, and the lead frames 2 on the strip body 1 being in two rows, the two rows of lead frames 2 being arranged in a rotating manner in the width direction of the strip body 1, and multiple lead frames 2 in the same row being evenly arranged along the length direction of the strip body 1.

[0035] The heat dissipation ribs 23 on the lead frame 2 are located on one side of the central axis of the strip body 1, and the pins 22 on the lead frame 2 are located on one side of the edge of the strip body 1. The heat dissipation ribs 23 of the two lead frames 2 arranged in a rotating manner on the strip body 1 are connected together, and the heat dissipation ribs 23 of multiple lead frames 2 in the same row are also connected together. This not only connects the two rotating lead frames 2 together through the heat dissipation ribs 23, but also connects the heat dissipation side of multiple lead frames 2 in the same row. At the same time, the pins 22 of two adjacent lead frames 2 in the same row are connected together, so that the other side of two adjacent lead frames 2 in the same row is also connected together. Through the cooperation of the heat dissipation ribs 23 and the pins 22, multiple lead frames 2 are arranged in a lead frame row before plastic encapsulation, which is convenient for packaging and supplying to the packaging and testing manufacturer.

[0036] On the main body 1 of the strip, two lead frames 2 in the same row form a group. The carrier plates 21 of the two lead frames 2 in the same group, the inner pins of the two lead frames 2, and the inner ends of the heat dissipation ribs 23 of the two lead frames 2 are all disconnected. This makes it easier to process the subsequent two lead frames 2 in the same group that need to be cut into independent lead frames 2. Only the pins 22 and the heat dissipation ribs 23 that are connected to each other need to be cut.

[0037] To prevent pins 22 from separating from the substrate 21, a connecting rib 3 is provided between adjacent sets of lead frames 2 in the same row. The two sides of the connecting rib 3 are spaced apart from the substrate 21 of the lead frame 2, the inner pins of the lead frame 2, and the inner ends of the heat dissipation ribs 23 of the lead frame 2. That is, the two sides of the connecting rib 3 are not connected to the substrate 21 of the lead frame 2, the inner pins of the lead frame 2, or the inner ends of the heat dissipation ribs 23 of the lead frame 2. Simultaneously, one end of the connecting rib 3 is connected to the heat dissipation ribs 23 that are interconnected on the two lead frames 2, and the other end of the connecting rib 3 is connected to the pins 22 that are interconnected on the two lead frames 2. It should be noted that the inner pin is the end of pin 22 closest to the substrate 21.

[0038] Both ends of the connecting rib 3 have inclined sections 31 and elongated holes 4. When the lead frame is processed, the punching step of the elongated hole 4 is before the punching step of the inclined section 31. The elongated hole 4 is a rectangular hole. The central axis of the elongated hole 4 is located on the cutting line when the lead frame is cut. The straight length of the inclined section 31 is less than the length of the elongated hole 4. The two ends of the inclined section 31 are located between the two ends of the elongated hole 4.

[0039] When the lead frame array needs to be cut, since the cutting edge formed by the upper and lower cutting blades used for cutting is on the same straight line as the central axis of the elongated hole 4, and the inclined section 31 is located between the two ends of the elongated hole 4, the inclined section 31 does not need to be cut during the cutting of the lead frame array. This effectively avoids deformation of the two adjacent sets of lead frames 2 during cutting, thus ensuring the quality of the lead frame 2. In addition, since the carrier plates 21 of the two lead frames 2 in the same group are disconnected, the inner pins of the two lead frames 2 are disconnected, and the inner ends of the heat dissipation ribs 23 of the two lead frames 2 are disconnected, when it is necessary to cut the two lead frames 2 in the same group of the lead frame array into independent lead frames 2, the two lead frames 2 in the same group only need to be cut by the interconnected pins 22 and the interconnected heat dissipation ribs 23. This ensures that the two adjacent sets of lead frames 2 in the same group will not deform during cutting, thus ensuring the quality of the lead frame 2.

[0040] In this invention, the inclination angle of the inclined section 31 on the connecting rib 3 is 150°. For a product with a lead frame 2 width of 52.2mm, the copper strip width required for producing the lead frame 2 is only 53.36mm. However, if the inclination angle of the inclined section 31 is 120°, the copper strip width required for producing the lead frame 2 with a width of 52.2mm is 54.74mm. That is, for products of the same width, the required raw material width is effectively reduced, and for a lead frame 2 with a width of 52.2mm, the raw material conversion rate is increased by 2.58%.

[0041] In this utility model, such as Figure 2 , Figure 3 As shown, the back of the substrate 21 on the lead frame 2 has a pressing step 211 on its edge. The pressing step 211 is concave relative to the back of the substrate 21. While the device presses the pressing step on the back of the substrate 21, it also forms side steps 212 around the substrate 21. The side steps 212 are concave relative to the front of the substrate 21 and convex relative to the sides of the substrate 21. Through the cooperation of the pressing step 211 and the side steps 212, the molding compound can be firmly wrapped around the edge of the substrate 21 during the subsequent molding process, thus effectively ensuring the quality of the substrate 21.

[0042] In this invention, the front side of the carrier plate 21 has raised ridges 213 on all four edges. The top of the raised ridges 213 is higher than the front side of the carrier plate 21, so that during subsequent molding, the workpiece on the molding mold is pressed against the raised ridges 213, preventing the molding material from flowing over the raised ridges 213 to the edge of the carrier plate 21, thereby effectively preventing overflow during the molding process.

[0043] To ensure heat dissipation on the carrier plate 21, the carrier plate 21 has two locking holes 214 on the side near the heat dissipation rib 23. Both locking holes 214 are oblong holes and are symmetrically arranged on the carrier plate 21. The opening edge of the locking holes 214 has a step 215 that is the same as the side step 212. The step 215 is formed in the same way as the side step 212, which is formed by pressing the step on the back of the carrier plate 21.

[0044] In the post-molding process, the heat dissipation ribs 23 need to be bent. Due to the connection between the carrier plate 21 and the heat dissipation ribs 23, the lead frame 2 may separate from the molding compound when the heat dissipation ribs 23 are bent. Therefore, in order to avoid this problem, the carrier plate 21 has three dovetail grooves 216 on the side near the heat dissipation ribs 23. The central axis of the dovetail grooves 216 is on the same straight line as the central axis of the locking hole 214, so as to ensure the quality of the encapsulation structure after molding.

[0045] Meanwhile, both sides of the substrate 21 and the side of the substrate 21 near the pin 22 have a locking groove 217. The locking groove 217 is a V-shaped groove, and the locking grooves 217 on both sides of the substrate 21 and the side of the substrate 21 near the pin 22 together form a U-shaped structure. This allows the locking groove 217 to increase the contact area with the molding compound during the subsequent molding process, thereby playing a better sealing role and preventing moisture from entering the product and affecting the chip performance.

[0046] Since the end of pin 22 closest to substrate 21 will be encapsulated simultaneously during the subsequent encapsulation process, meaning a portion of the inner pin will be encapsulated along with substrate 21, side steps 221 are provided on both sides of pin 22 during processing. The side steps 221 have a raised or recessed structure relative to the side of pin 22. This increases the contact area between the encapsulating material and pin 22 during subsequent processing, strengthens the encapsulation of the encapsulating material, makes the position of pin 22 within the encapsulation body more stable, and improves the reliability of the product.

[0047] Furthermore, in this invention, the lead frame 2, after being encapsulated, is based on the thickness direction of the encapsulating material, such as... Figure 7 As shown, the inner side of the pin 22 in the lead frame 2 is located in the middle of the molding compound, and the substrate 21 of the lead frame 2 is located on top of the molding compound. In the package structure formed after encapsulation, the pin 22 and the heat dissipation rib 23 in the lead frame 2 are both bent downward relative to the horizontal surface and attached to the PCB board, while the heat sink is attached to the top of the package structure to achieve top heat dissipation.

[0048] In order to facilitate the subsequent cutting of two sets of lead frames 2 in the same group, one or more material distribution holes 5 arranged coaxially with the elongated hole 4 can be provided at the connection of the heat dissipation horizontal ribs 23 in the two sets of lead frames 2 in the same group. One or more material distribution holes 5 arranged coaxially with the elongated hole 4 can also be provided at the connection of the pins 22 in the two sets of lead frames 2 in the same group.

[0049] Those skilled in the art should understand that the above embodiments are merely for clearly illustrating the present invention and are not intended to limit the scope of the present invention. Those skilled in the art can make other changes or modifications based on the above disclosure, and these changes or modifications still fall within the scope of the present invention.

Claims

1. A reinforced upper heat dissipation lead frame, characterized in that, The material includes a strip body (1), which has two rows of lead frames (2) arranged opposite each other. The heat dissipation ribs (23) on the two lead frames (2) are connected together, and the pins (22) on multiple lead frames (2) in the same row are connected together. The heat dissipation ribs (23) on multiple lead frames (2) in the same row are connected together. Two lead frames (2) in the same row form a group. The two lead frames (2) in the same group are connected to each other. The two lead frames (2) ... The heat dissipation ribs (23) of the carrier plate (21) of the frame (2) are all disconnected at their inner ends. There is a connecting rib (3) between two adjacent sets of lead frames (2). There is a certain gap between the two sides of the connecting rib (3) and the lead frame (2). One end of the connecting rib (3) is connected to the pin (22) of the lead frame (2), and the other end of the connecting rib (3) is connected to the heat dissipation rib (23) of the lead frame (2). Both ends of the connecting rib (3) have an inclined section (31) and an elongated hole (4). The inclined section (31) is located between the two ends of the elongated hole (4).

2. The reinforced upper heat dissipation lead frame according to claim 1, characterized in that, The tilt angle of the inclined segment (31) is 150°.

3. The reinforced upper heat dissipation lead frame according to claim 1, characterized in that, The edge of the back side of the slide plate (21) has a pressing step (211), and the four sides of the front side of the slide plate (21) have a side step (212).

4. The reinforced upper heat dissipation lead frame according to any one of claims 1 to 3, characterized in that, The front edge of the slide plate (21) has raised edges (213).

5. The reinforced upper heat dissipation lead frame according to claim 4, characterized in that, The carrier plate (21) has two glue-locking holes (214) on the side near the heat dissipation rib (23). The two glue-locking holes (214) are symmetrically arranged on the carrier plate (21), and the opening edge of the glue-locking hole (214) has an upward protruding step (215).

6. The reinforced upper heat dissipation lead frame according to claim 5, characterized in that, The carrier plate (21) also has three dovetail grooves (216) on the side near the heat dissipation rib (23), and the dovetail grooves (216) and the locking holes (214) are on the same straight line.

7. The reinforced upper heat dissipation lead frame according to any one of claims 1 to 3, characterized in that, The substrate (21) has a locking groove (217) on both sides and on the side of the substrate (21) near the pin (22).

8. The reinforced upper heat dissipation lead frame according to any one of claims 1 to 3, characterized in that, The pin (22) is also provided with side steps (221) on both sides near the end of the substrate (21).

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