Safety level TO-220HEMT packaging lead frame structure

Abstract

The utility model provides a safety level TO-220HEMT packaging lead frame structure, which comprises a plurality of lead frame units, each lead frame unit comprises a radiating fin, a ceramic substrate and an external pin which are arranged in sequence, the radiating fin is provided with a chip carrying area used for carrying the ceramic substrate, one surface of the ceramic substrate is connected with the radiating fin, and the other surface of the ceramic substrate is connected with the external pin. One surface of the ceramic substrate is provided with a plurality of external pins, the other surface of the ceramic substrate is provided with a plurality of chip carrying islands, one ends of the external pins are connected with the chip carrying islands, and the ceramic substrate is arranged between the radiating fin and the external pins, so that the external pins, the chip and the radiating fin can be electrically isolated, and potential safety hazards such as electric leakage, ignition and electrical contact when the terminal is used are solved; and meanwhile, the ceramic substrate provides a heat dissipation channel between the chip and the heat dissipation sheet, so that the lead frame has an excellent heat dissipation effect.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of semiconductor packaging, and specifically relates to a safety regulation level TO-220HEMT packaging lead frame structure. BACKGROUND

[0002] After the semiconductor chip is manufactured, it cannot be directly assembled on the PCB for use due to its fragility. The I / O on the chip needs to be led out and connected with the circuit on the PCB, and at the same time, the chip needs to be protected to prevent damage, corrosion and contamination. The purpose of semiconductor packaging is to solve these problems, which leads the I / O on the chip to the lead frame, physically isolates and protects the semiconductor chip, and manages the heat system of the chip.

[0003] The lead frame plays a very key role in semiconductor packaging. The lead frame is used to fix the semiconductor chip, as a connecting bridge between the chip I / O and the PCB, and to transfer the heat generated by the chip to the outside for heat dissipation. However, in the prior art, the TO-220 lead frame has some defects. For example, the middle pin is directly connected with the heat sink, which may cause safety hazards such as electric leakage, electric spark, and electric contact in terminal use. In addition, the existing TO-220 lead frame cannot meet the requirements of multi-chip isolation packaging, which limits its use in high-performance and high-density integrated applications. SUMMARY

[0004] In view of the deficiencies in the prior art, the purpose of the utility model is to provide a safety regulation level TO-220HEMT packaging lead frame structure to solve the problems mentioned in the background technology section.

[0005] The utility model realizes the following technical solutions:

[0006] A safety regulation level TO-220HEMT packaging lead frame structure includes a plurality of lead frame units, the lead frame unit includes a heat sink, a ceramic substrate and an external pin arranged in sequence, the heat sink is provided with a carrier area for carrying the ceramic substrate, one side of the ceramic substrate is connected with the heat sink, the other side of the ceramic substrate is provided with a plurality of carrier islands, and one end of the external pin is connected with the carrier island.

[0007] Further, the external pin includes a middle pin and a plurality of side edge pins distributed on the side of the middle pin.

[0008] Further, the slide island includes a first slide island and a second slide island, the first slide island is provided with a notch groove and a mounting portion located at the side of the notch groove, and the second slide island is arranged at the notch groove; the middle pin includes a first connecting portion, a second connecting portion and a third connecting portion, the first connecting portion is connected to the mounting portion, the second connecting portion is arranged in the space corresponding to the central region of the ceramic substrate, and the third connecting portion is inclinedly connected to the first connecting portion and the second connecting portion.

[0009] Further, the side pin is connected with a solder pad, one end of the solder pad extends towards the second connecting portion.

[0010] Further, the solder pad is provided with a through hole at opposite corners.

[0011] Further, the connection between the side pin and the solder pad is provided with a first shape groove.

[0012] Further, the heat sink is also provided with a connecting area and a second type groove separating the connecting area and the slide area, and the connecting area is provided with an assembly hole.

[0013] Further, the external pin includes a side rib and a middle rib connecting the middle pin and the side pin, and the side rib is provided with two or more positioning holes.

[0014] Further, the two end faces of the ceramic substrate are provided with a metallization layer.

[0015] Further, the ceramic substrate is an aluminum nitride ceramic substrate.

[0016] The beneficial effects of the utility model are as follows: a safety level TO-220HEMT packaging lead frame structure includes a plurality of lead frame units, the lead frame unit includes a heat sink, a ceramic substrate and an external pin arranged in sequence, the heat sink is provided with a slide area for bearing the ceramic substrate, one side of the ceramic substrate is connected with the heat sink, the other side of the ceramic substrate is provided with a plurality of slide islands, one end of the external pin is connected with the slide island, the ceramic substrate is arranged between the heat sink and the external pin, the external pin, the chip and the heat sink are electrically isolated, thereby solving the safety hazards such as electric leakage, sparking and electrical contact during terminal use, and the ceramic substrate provides a heat dissipation channel between the chip and the heat sink, so that the lead frame has excellent heat dissipation effect. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is the front view of the lead frame of the utility model.

[0018] Figure 2 It is the front view of the lead frame unit of the utility model.

[0019] Figure 3 It is the side view of the lead frame unit of the utility model.

[0020] Figure 4 It is the perspective view of the lead frame unit of the utility model.

[0021] Figure 5 It is the explosion view of the lead frame unit of the utility model.

[0022] Among them, the above-mentioned drawing includes the following figure marks:

[0023] 1, fin; 11, carrier area; 111, step; 12, second type groove; 13, connecting area; 131, assembly hole; 132, connecting rib; 2, ceramic substrate; 21, metallization layer; 3, first carrier island; 31, notch groove; 32, mounting part; 4, second carrier island; 5, external pin; 51, middle pin; 511, first connecting part; 512, second connecting part; 513, third connecting part; 52, side pin; 53, solder pad; 531, through hole; 54, first shape groove; 55, edge rib; 551, positioning hole; 56, middle rib. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be described clearly and completely below in combination with the drawings in the embodiments of the utility model. It needs to be explained here that the description of these embodiments is used to help understanding the utility model, but does not constitute the limitation on the utility model. In addition, the technical features involved in each embodiment of the utility model described below can be combined with each other as long as they do not conflict with each other.

[0025] Referring to Figures 1 to 5 As shown in the figure, a safety regulation level TO-220 HEMT package lead frame structure includes a plurality of lead frame units, the lead frame unit includes a fin 1, a ceramic substrate 2 and an external pin 5 arranged in sequence, the fin 1 is provided with a carrier area 11 for bearing the ceramic substrate 2, one side of the ceramic substrate 2 is connected with the fin 1, the other side of the ceramic substrate 2 is provided with a plurality of carrier islands, one end of the external pin 5 is connected with the carrier island.

[0026] Among them, the number of carrier islands is multiple and is independently arranged, thereby the multi-chip system level package can be carried out, the different carrier islands can be interconnected through soldering wire according to product design requirements, the lead frame is particularly applied to the packaging of D-mode HEMT power device, in addition, the multi-chip system package is beneficial to improve the product power density, and meanwhile reduces the product packaging cost.

[0027] By arranging the ceramic substrate 2 between the heat sink 1 and the external pin 5, the external pin 5, the chip and the heat sink 1 are electrically isolated, thereby solving the safety hazards such as leakage, sparking and electrical contact during terminal use, and the ceramic substrate 2 provides a heat dissipation channel between the chip and the heat sink 1, so that the lead frame has excellent heat dissipation effect.

[0028] The external pin 5 includes a middle pin 51 and a plurality of side pins 52 distributed on the sides of the middle pin 51, the number of the side pins 52 is optional, and the side pins 52 are connected with pads 53, and the I / O on the chip can be led out to the pads 53 through wire bonding, and then interconnected with the PCB through the side pins 52.

[0029] Specifically, the carrier island includes a first carrier island 3 and a second carrier island 4, the first carrier island 3 is provided with a notch groove 31 and a mounting portion 32 located on the side of the notch groove 31, and the second carrier island 4 is arranged at the notch groove 31; the middle pin 51 includes a first connecting portion 511, a second connecting portion 512 and a third connecting portion 513, the first connecting portion 511 is connected to the mounting portion 32, the second connecting portion 512 is arranged in the space corresponding to the central region of the ceramic substrate 2, that is, the center line of the second connecting portion 512 is aligned with or slightly deviates from the center line of the ceramic substrate 2, and then the third connecting portion 513 is inclinedly connected to the first connecting portion 511 and the second connecting portion 512, and one end of the pad 53 extends towards the second connecting portion 512. Through the above structure, the area of the pad 53 can be increased as much as possible in the relatively narrow space, so that more wire bonding can be installed on the pad 53, and the length of the third connecting portion 513 can be extended, thereby increasing the length of the heat conduction path of the pad 53 when welding, so as to avoid damage to the chip due to heat.

[0030] The pad 53 is provided with a through hole 531 at the diagonal position, which can tightly combine the plastic package and the pad 53 together, and avoid the separation of the plastic package and the pad 53 due to heat during terminal welding, causing the falling off of the welding point.

[0031] The connection between the side pin 52 and the pad 53 is provided with a first shape groove 54, and the first shape groove 54 transversely passes through the second connecting portion 512, and the first shape groove 54 is preferably V-shaped, which is beneficial to the engagement of the plastic package and the external pin 5, and increases the bonding strength; and the first shape groove 54 can effectively prevent external moisture from penetrating into the product through the bonding surface, thereby avoiding the pollution and corrosion of the chip by the moisture.

[0032] The heat sink 1 is provided with a second groove 12, and is divided into a connecting area 13 and a carrier area 11 by the second groove 12. The connecting area 13 is provided with an assembly hole 131 and a connecting rib 132. The second groove 12 is preferably V-shaped, which is beneficial to the engagement of the plastic package and the external pin 5, and increases the bonding strength. The second groove 12 can effectively prevent external moisture from penetrating into the product along the bonding surface, avoiding the pollution and corrosion of the chip by the moisture. The assembly hole 131 is used for fixing the product on the heat sink during terminal use and positioning the lead frame during packaging production.

[0033] The connecting rib 132 connects the heat sinks 1 of two adjacent lead frame units, which is beneficial to strengthening the firmness of the lead frame and reducing the deformation of the lead frame.

[0034] The back of the carrier area 11 is provided with a step 111, which is beneficial to wrapping the edge of the heat sink 1 by the plastic package, increasing the bonding strength between the plastic package and the heat sink 1. The step 111 can effectively prevent external moisture from penetrating into the product along the bonding surface, avoiding the pollution and corrosion of the chip by the moisture.

[0035] The external pin 5 includes a side rib 55 and a middle rib 56 connecting the middle pin 51 and the side pin 52, and the side rib 55 is provided with two or more positioning holes 551. The side rib 55 and the middle rib 56 connect the external pins 5 of two adjacent lead frame units, which is beneficial to strengthening the firmness of the lead frame and reducing the deformation of the lead frame. The positioning holes 551 are beneficial to the positioning of the lead frame during production.

[0036] The connecting rib 132, the side rib 55 and the middle rib 56 can connect the products together, so that the multiple lead frame units are connected into a whole lead frame, which can effectively prevent the deformation of the lead frame during the handling, transportation and use of the product.

[0037] Both end surfaces of the ceramic substrate 2 are provided with a metallized layer 21. The ceramic substrate 2 is formed by a metallization process on both surfaces to form the metallized layer 21. The ceramic substrate 2 is sintered with the carrier area 11 of the heat sink 1 through one of the metallized layers 21, and is sintered with the first connecting part 511 of the external pin 5 through the other metallized layer 21.

[0038] The ceramic substrate 2 is an aluminum nitride ceramic substrate, the thermal conductivity of the aluminum nitride ceramic substrate is very high, and the specific value is about 310 W / mK, a large amount of heat is generated when the island chip, especially the semiconductor power device chip, works, the heat can be transmitted to the cooling fin 1 through the ceramic substrate 2 and then radiated through the radiator, the dielectric constant of aluminum nitride is about 8.8, and aluminum nitride is an excellent electrically insulating material, meanwhile, the breakdown field strength of aluminum nitride is as high as 11.7X106V / cm, so that the aluminum nitride has excellent voltage resistance, the aluminum nitride ceramic substrate can effectively electrically isolate the cooling fin 1 and the external pin 5, and avoid the safety hazards of electric leakage, sparking and electrical contact.

[0039] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0040] In the description of the present application, the terms "first" and "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first" and "second" can explicitly or implicitly include one or more of the features.

[0041] The above is only the preferred embodiment of the present application, and is not used to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A safety-grade TO-220 HEMT package lead frame structure, characterized in that: The device includes several lead frame units, each comprising a heat sink (1), a ceramic substrate (2), and external leads (5) arranged sequentially. The heat sink (1) has a carrier area (11) for supporting the ceramic substrate (2). One side of the ceramic substrate (2) is connected to the heat sink (1), and the other side of the ceramic substrate (2) has several carrier islands. One end of the external leads (5) is connected to the carrier islands. The external pin (5) includes a middle pin (51) and a number of side pins (52) distributed on the side of the middle pin (51). The substrate island includes a first substrate island (3) and a second substrate island (4). The first substrate island (3) is provided with a notch (31) and a mounting portion (32) located on the side of the notch (31). The second substrate island (4) is disposed at the notch (31). The intermediate pin (51) includes a first connecting portion (511), a second connecting portion (512) and a third connecting portion (513). The first connecting portion (511) is connected to the mounting portion (32). The second connecting portion (512) is disposed in the space corresponding to the central area of ​​the ceramic substrate (2). The third connecting portion (513) is obliquely connected to the first connecting portion (511) and the second connecting portion (512).

2. The safety-grade TO-220 HEMT package lead frame structure according to claim 1, characterized in that: The side pin (52) is connected to a pad (53), one end of which extends toward the second connection portion (512).

3. The safety-grade TO-220 HEMT package lead frame structure according to claim 2, characterized in that: The pad (53) has a through hole (531) at the diagonal.

4. The safety-grade TO-220 HEMT package lead frame structure according to claim 3, characterized in that: A first groove (54) is provided at the connection between the side pin (52) and the pad (53).

5. The safety-grade TO-220 HEMT package lead frame structure according to claim 1, characterized in that: The heat sink (1) is also provided with a connection area (13) and a second groove (12) separating the connection area (13) and the carrier area (11), and the connection area (13) is provided with an assembly hole (131).

6. The safety-grade TO-220 HEMT package lead frame structure according to claim 2, characterized in that: The external pin (5) includes a side rib (55) and a middle rib (56) connecting the middle pin (51) and the side pin (52), and the side rib (55) is provided with two or more positioning holes (551).

7. The safety-grade TO-220 HEMT package lead frame structure according to claim 1, characterized in that: The ceramic substrate (2) has metallization layers (21) on both ends.

8. A safety-grade TO-220 HEMT package lead frame structure according to any one of claims 1 to 7, characterized in that: The ceramic substrate (2) is an aluminum nitride ceramic substrate.

Images