HEMT packaging TO-220 double-island lead frame structure

Abstract

The invention provides an HEMT (High Electron Mobility Transistor) packaging TO-220 double-island lead frame structure, which comprises a plurality of cooling fin units, and is characterized in that each cooling fin unit is provided with a chip carrying area which is used for carrying a semiconductor chip and a bonding wire; the chip carrying island is connected with the radiating fin unit and is used for carrying a semiconductor chip and a bonding wire; the radiating fin unit further comprises external pins, the external pins comprise a middle pin and at least one side pin distributed on the side of the middle pin, the middle pin is connected with the chip carrying area, and the side pin is provided with a bonding wire area. The chip carrying island and the chip carrying area of the radiating fin unit are independent from each other, so that system packaging of multiple chips can be realized, electrical interference among different chips is avoided, and the power density of a product is increased; and through the radiating fin unit, a product can be conveniently assembled on a radiator when the terminal is used, the heat of the chip can be timely dissipated, and the product can work in a safe temperature range.

Description

Technical Field

[0001] The invention relates to the field of semiconductor packaging, and in particular to a HEMT packaging TO-220 double island lead frame structure. Background Art

[0002] Semiconductor power device chips and power IC chips generate a lot of heat when working, causing the temperature inside the chip to rise rapidly. The increase in chip temperature will not only lead to performance degradation and reliability reduction, but also may cause safety accidents in extreme cases. Therefore, before terminal use, in addition to the need to lead out the I / O on the chip to connect to the electrodes on the PCB board, it is also necessary to carry out heat dissipation design to ensure that the chip works within a safe temperature range.

[0003] As the carrier of the integrated circuit chip, the lead frame realizes the electrical connection between the internal circuit lead end of the chip and the external lead through the bonding wire, and is a key structural component for forming an electrical circuit. It not only stabilizes the chip and conducts signals, but also is responsible for transmitting heat. In the prior art, a TO-220 lead frame usually has only one chip mounting island, that is, only one high electron mobility transistor (HEMT) can be installed. For example, Chinese patent document CN206210784U discloses a partially insulated TO-220 lead frame.

[0004] In order to realize the assembly of two or more chips, avoid electrical interference between different chips, and meet the heat dissipation requirements, it is necessary to first assemble an insulating substrate on the chip carrier island of the heat sink, and then assemble different semiconductor chips on the insulating substrate. However, the increase of insulating substrates will lead to a longer packaging process and an increase in packaging difficulty, which will lead to a significant increase in packaging costs. Summary of the invention

[0005] In view of the deficiencies in the prior art, the purpose of the present invention is to propose a HEMT package TO-220 double island lead frame structure to solve the problems mentioned in the above background technology section.

[0006] The present invention is achieved through the following technical solutions:

[0007] A HEMT package TO-220 double island lead frame structure includes a plurality of heat sink units, each heat sink unit is provided with a wafer carrier area, and the wafer carrier area is used to carry semiconductor chips and welding wires; it also includes a wafer carrier island connected to the heat sink unit, and the wafer carrier island is used to carry semiconductor chips and welding wires; it also includes external pins, and the external pins include a middle pin and at least one side pin distributed on the side of the middle pin, the middle pin is connected to the wafer carrier area, and the side pin is provided with a welding wire area.

[0008] Furthermore, it also includes an upper transverse rib, a middle transverse rib and a lower transverse rib for connecting two adjacent heat sink units, and the middle transverse rib and the lower transverse rib connect the middle pin and the side pin.

[0009] Furthermore, it also includes connecting ribs for connecting two adjacent heat sink units and the wafer carrier island, and reinforcing ribs connecting the middle transverse ribs and the connecting ribs.

[0010] Furthermore, the heat sink unit, the wafer carrier island and the external pins are integrally formed.

[0011] Furthermore, a first-shaped groove is provided on the front side of the heat sink unit, which is divided into a connection area and the wafer carrier area by the first-shaped groove, and an assembly hole is provided in the connection area.

[0012] Furthermore, the heat sink unit is provided with a through groove in the area located at the first-shaped groove, and the back edge corresponding to the chip-carrying area is provided with a first step.

[0013] Furthermore, a through hole is provided in the welding line area.

[0014] Furthermore, a second step is provided between the wafer carrier area and the wafer carrier island.

[0015] Furthermore, a hollow partition area is provided between the wafer carrier island and the wafer carrier area and the wire bonding area.

[0016] Furthermore, chamfers are provided at the connection points between the side ribs and the middle pins and the side pins.

[0017] The beneficial effects of the present invention are as follows: a HEMT package TO-220 double island lead frame structure includes a plurality of heat sink units, wherein the heat sink units are provided with a chip carrier area, wherein the chip carrier area is used to carry semiconductor chips and welding wires; further includes a chip carrier island connected to the heat sink unit, wherein the chip carrier island is used to carry semiconductor chips and welding wires; further includes an external pin, wherein the external pin includes a middle pin, and at least one side pin distributed on the side of the middle pin, wherein the middle pin is connected to the chip carrier area, and the side pin is provided with a welding wire area. The present invention not only provides a chip carrier area in the heat sink unit, but also A unique carrier island is set up, and the carrier area of ​​the carrier island and the heat sink unit are independent of each other, so that multi-chip system packaging can be realized, while avoiding electrical interference between different chips and increasing the power density of the product; and through the heat sink unit, it is convenient to assemble the product on the radiator when it is used by the terminal, which is beneficial to dissipate the heat of the chip in time and make the product work within a safe temperature range; the carrier area of ​​the carrier island and the heat sink unit are independent of each other, avoiding the use of insulating substrates and reducing material costs. At the same time, the reduction of insulating substrates shortens the process flow and reduces the difficulty of the process, thereby reducing the packaging cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a front view of the lead frame of the present invention.

[0019] Figure 2 It is a front view of a single heat sink unit and a wafer carrier island of the present invention.

[0020] Figure 3 It is a side view of a single heat sink unit and a wafer carrier island of the present invention.

[0021] Figure 4 It is a three-dimensional diagram of a single heat sink unit and a wafer carrier island of the present invention.

[0022] The above drawings include the following reference numerals:

[0023] 1. Heat sink unit; 11. Chip carrier area; 12. Connection area; 121. Assembly hole; 13. Through groove; 14. First-shaped groove; 15. First step; 16. Second step; 2. Chip carrier island; 3. External pin; 31. Middle pin; 32. Side pin; 321. Wire welding area; 3211. Through hole; 33. Chamfer; 34. Notch; 4. Upper horizontal rib; 5. Middle horizontal rib; 6. Lower horizontal rib; 7. Connecting rib; 8. Reinforcing rib; 9. Hollow partition area. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in each embodiment of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0025] Reference Figures 1 to 4 As shown, a HEMT package TO-220 double island lead frame structure includes a plurality of heat sink units 1, wherein the heat sink unit 1 is provided with a wafer carrier area 11, wherein the wafer carrier area 11 is used to carry semiconductor chips and welding wires; further includes a wafer carrier island 2 connected to the heat sink unit 1, wherein the wafer carrier island 2 is used to carry semiconductor chips and welding wires; further includes an external pin 3, wherein the external pin 3 includes a middle pin 31, and at least one side pin 32 distributed on the side of the middle pin 31, wherein the middle pin 31 is connected to the wafer carrier area 11, and the side pin 32 is provided with a welding wire area 321.

[0026] The present invention not only provides a chip carrier area 11 on the heat sink unit 1, but also independently provides a chip carrier island 2. The chip carrier island 2 and the chip carrier area 11 of the heat sink unit 1 are independent of each other, so that a multi-chip system package can be realized, while avoiding electrical interference between different chips and increasing the power density of the product. In addition, through the heat sink unit 1, it is convenient to assemble the product on the radiator when the terminal is used, which is conducive to timely dissipating the heat of the chip and making the product work in a safe temperature range. The chip carrier island 2 and the chip carrier area 11 of the heat sink unit 1 are independent of each other, avoiding the use of an insulating substrate and reducing material costs. At the same time, the reduction of the insulating substrate shortens the process flow and reduces the difficulty of the process, thereby reducing the packaging cost.

[0027] The I / O on the chip can be interconnected with the wafer carrier island 2 or the wafer carrier area 11 by means of wire bonding. In the present invention, the number of the side pins 32 is two, and the number of the side pins 32 is set according to user requirements.

[0028] It also includes an upper transverse rib 4, a middle transverse rib 5 and a lower transverse rib 6 for connecting two adjacent heat sink units 1. The middle transverse rib 5 and the lower transverse rib 6 connect the middle pin 31 and the side pin 32. The arrangement of the upper transverse rib 4, the middle transverse rib 5 and the lower transverse rib 6 is beneficial to increase the strength of the lead frame and avoid deformation of the lead frame during use.

[0029] It also includes a connecting rib 7 for connecting two adjacent heat sink units 1 and the wafer carrier island 2, and a reinforcing rib 8 connecting the middle transverse rib 5 and the connecting rib 7. The cooperation of the connecting rib 7 and the reinforcing rib 8 is conducive to increasing the strength of the lead frame and avoiding deformation of the lead frame during use.

[0030] The heat sink unit 1, the chip carrier island 2 and the external pin 3 are integrally formed. The integral forming technology is used to reduce mold costs, and the integral forming can provide overall strength.

[0031] The heat sink unit 1 is provided with an assembly hole 12. The arrangement of the assembly hole 12 facilitates the positioning of the lead frame during the packaging process and avoids deviation of the lead frame.

[0032] The "popcorn" effect refers to the phenomenon that during the semiconductor chip packaging process, the water absorbed inside the device vaporizes and expands during high-temperature heat treatment (such as reflow soldering, wave soldering, etc.), causing the internal pressure of the device to increase, thereby propping up or even destroying the plastic packaging colloid or substrate. This phenomenon is particularly obvious during the cooling process, because the internal material of the device has inconsistent rates of thermal expansion and contraction, which may cause cracks in the internal material. When the absorbed water vapor content is higher than a certain threshold, the popcorn phenomenon will occur. This effect not only causes device damage, but is often accompanied by a sound similar to popcorn popping when it occurs, hence the name "popcorn" effect.

[0033] The front of the heat sink unit 1 is provided with a first-shaped groove 14, which is divided into a connection area 12 and the wafer carrier area 11. The connection area 12 is provided with an assembly hole 121, and upper transverse ribs 4 are provided at both ends of the connection area 12. The heat sink unit 1 is provided with a through groove 13 in the area located in the first-shaped groove 13, and a first step 15 is provided at the back edge corresponding to the wafer carrier area 11.

[0034] The first groove 14 is preferably V-shaped, and the through groove 13 is U-shaped, so as to facilitate processing and forming.

[0035] The assembly hole 121 is provided to facilitate positioning of the lead frame during the packaging process, thereby preventing deviation of the lead frame.

[0036] The provision of the through groove 13, the first-shaped groove 14 and the first step 15 is beneficial to enhancing the bonding strength between the plastic package and the lead frame, and can effectively prevent the infiltration of water vapor, avoid contamination and corrosion of the semiconductor chip, and avoid the "popcorn" effect of the product when heated.

[0037] The welding line area 321 is provided with a through hole 3211. The provision of the through hole 3211 can increase the bonding strength between the plastic package body and the welding area, and avoid welding line failure caused by delamination.

[0038] The middle pin 31 and the side pin 32 are both provided with a notch 34, which is V-shaped. The notch 34 can increase the bonding strength between the plastic package and the lead frame, effectively prevent water vapor from penetrating, and avoid contamination and corrosion of the welding wire and the "popcorn" effect caused by heating of the product, which may cause the welding point to fall off.

[0039] A second step 16 is provided between the wafer carrier area 11 and the wafer carrier island 2 . The provision of the second step 16 is conducive to the plastic package completely wrapping up the wafer carrier island 2 , thereby achieving insulation isolation between the wafer carrier island 2 and the wafer carrier area 11 .

[0040] A hollow partition area 9 is provided between the wafer carrier island 2 and the wafer carrier area 11 and the wire bonding area 321. Through the setting of the hollow partition area 9, when the wire bonding area 321 is bonding the wire, the heat needs to be conducted to the wafer carrier area 11 via the side pins 32 and the middle pins 31. During this process, the heat will be dissipated, thereby avoiding the possibility of heat being directly conducted to the chip and protecting the chip from thermal damage.

[0041] The connection between the side rib and the middle pin 31 and the side pin 32 is provided with a chamfer 33. The setting of the chamfer 33 is conducive to cutting off the lower transverse rib 6. The chamfer 33 provides a clear cutting edge, which helps to improve the cutting quality and reduce the damage or defective rate caused by inaccurate cutting. When used in the terminal, the chamfer 33 design makes it easier for the pin to be inserted into the corresponding hole. This is because the chamfer 33 can reduce the friction between the pin and the hole wall, so that the pin can pass through the hole more smoothly, thereby improving assembly efficiency and accuracy.

[0042] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0043] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A HEMT package TO-220 double island lead frame structure, characterized in that: It comprises a plurality of heat sink units (1), wherein the heat sink units (1) are provided with a chip carrier area (11), and the chip carrier area (11) is used to carry semiconductor chips and bonding wires; It also includes a chip carrier island (2) connected to the heat sink unit (1), and the chip carrier island (2) is used to carry semiconductor chips and bonding wires; It also includes external pins (3), the external pins (3) including a middle pin (31) and at least one side pin (32) distributed on the side of the middle pin (31), the middle pin (31) is connected to the carrier area (11), and the side pin (32) is provided with a welding wire area (321).

2. A HEMT package TO-220 double island lead frame structure according to claim 1, characterized in that: It also includes an upper transverse rib (4), a middle transverse rib (5) and a lower transverse rib (6) for connecting two adjacent heat sink units (1), wherein the middle transverse rib (5) and the lower transverse rib (6) connect the middle pin (31) and the side pin (32).

3. A HEMT package TO-220 double island lead frame structure according to claim 2, characterized in that: It also includes connecting ribs (7) for connecting two adjacent heat sink units (1) and the wafer carrier island (2), and reinforcing ribs (8) connecting the middle transverse ribs (5) and the connecting ribs (7).

4. The HEMT package TO-220 double island lead frame structure according to claim 1, characterized in that: The heat sink unit (1), the chip carrier island (2) and the external pin (3) are integrally formed.

5. The HEMT package TO-220 double island lead frame structure according to claim 1, characterized in that: The front side of the heat sink unit (1) is provided with a first-shaped groove (14), which is divided into a connection area (12) and a carrier area (11) by the first-shaped groove (14), and the connection area is provided with an assembly hole (121).

6. A HEMT package TO-220 double island lead frame structure according to claim 5, characterized in that: The heat sink unit (1) is provided with a through groove (13) in the area located at the first-shaped groove (13), and a first step (15) is provided at the back edge corresponding to the wafer carrier area (11).

7. The HEMT package TO-220 double island lead frame structure according to claim 1, characterized in that: The welding line area (321) is provided with a through hole (3211).

8. The HEMT package TO-220 double island lead frame structure according to claim 1, characterized in that: A second step (16) is provided between the wafer carrier area (11) and the wafer carrier island (2).

9. The HEMT package TO-220 double island lead frame structure according to claim 1, characterized in that: A hollow partition area (9) is provided between the wafer carrier island (2) and the wafer carrier area (11) and the welding line area (321).

10. The HEMT package TO-220 double island lead frame structure according to claim 2, characterized in that: The connection points between the side ribs and the middle pins (31) and the side pins (32) are all provided with chamfers (33).

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