Packaging structure and radio frequency power amplifier device

Abstract

The utility model provides a packaging structure and a radio frequency power amplifier device, the packaging structure comprises a chip, a diamond composite material layer and a circuit board, the diamond composite material layer is installed on the circuit board, and the chip is installed on one side, far away from the circuit board, of the diamond composite material layer. Compared with a packaging structure in the prior art, according to the packaging structure and the radio frequency power amplifier device, after the second-stage heat sink is arranged to be the diamond composite material layer and installed on the circuit board, the first-stage heat sink is omitted, and the chip is connected to the diamond composite material layer, so that the heat conduction and heat dissipation capacity of the packaging structure is greatly improved, and the thermal stress is reduced; and one-step welding is simplified, so that the process is shortened, the cost is reduced, and the quality risk is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of packaging, in particular to a packaging structure and a radio frequency power amplifier device. Background Art

[0002] The packaging structure of existing RF power amplifier devices is that the LDMOS or GaN chip and the first-level heat sink, and the first-level heat sink and the second-level heat sink are connected together through welding layers, and the second-level heat sink is embedded in the PCB board as a heat dissipation base. However, the packaging structure of existing RF power amplifier devices has a long heat dissipation path, poor heat dissipation effect, large thermal stress between the chip and the first-level heat sink, and between the first-level heat sink and the second-level heat sink, poor reliability, complicated process, and high quality risk. Utility Model Content

[0003] Based on this, it is necessary to provide a packaging structure and a RF power amplifier device to address the problems of existing RF power amplifier device packaging structures, such as long heat dissipation path, poor heat dissipation effect, large thermal stress between the chip and the first-level heat sink and between the first-level heat sink and the second-level heat sink, poor reliability, complicated process and high quality risk.

[0004] The technical solution is as follows:

[0005] On the one hand, a packaging structure is provided, which includes a chip, a diamond composite material layer and a circuit board, wherein the diamond composite material layer is mounted on the circuit board, and the chip is mounted on a side of the diamond composite material layer away from the circuit board.

[0006] The technical solution is further described below:

[0007] In one embodiment, the thermal conductivity of the diamond composite material layer is greater than or equal to 600 W / mK.

[0008] In one embodiment, the thermal expansion coefficient of the diamond composite material layer is greater than or equal to 5 ppm / K and less than or equal to 8 ppm / K.

[0009] In one embodiment, the diamond composite material layer includes at least one of diamond copper, diamond aluminum, diamond silver and diamond magnesium.

[0010] In one embodiment, the circuit board is provided with a connecting portion, and the connecting portion is used for mounting the diamond composite material layer.

[0011] In one of the embodiments, the connecting portion is configured as a groove, and the diamond composite material layer is embedded in the groove.

[0012] In one of the embodiments, the packaging structure further includes an adhesive layer, and the adhesive layer is filled between the outer wall of the diamond composite material layer and the inner wall of the groove to fix the diamond composite material layer on the circuit board.

[0013] In one embodiment, the packaging structure further includes a welding layer, and the welding layer is located between the chip and the diamond composite material layer to fix the chip on the diamond composite material layer.

[0014] In one embodiment, the welding layer is bonded to the chip and the diamond composite material layer.

[0015] On the other hand, a radio frequency power amplifier device is provided, comprising the packaging structure.

[0016] The packaging structure and RF power amplifier device in the above embodiment, when used, after the secondary heat sink is set as a diamond composite material layer and installed on the circuit board, the primary heat sink is cancelled, and the chip is connected to the diamond composite material layer to complete the packaging. The RF power amplifier device in this application has at least the following advantages: 1. The diamond composite material layer has a high thermal conductivity, which increases the thermal conductivity of the secondary heat sink and enhances the thermal conductivity of the RF power amplifier device. 2. The primary heat sink is cancelled, which shortens the heat dissipation path of the packaging structure and improves the heat dissipation efficiency of the packaging structure. 3. The welding layer between the primary heat sink and the secondary heat sink is cancelled, so that the interface thermal resistance of the packaging structure is reduced, the heat dissipation path is shorter, the heat dissipation effect is better, and it can meet the use requirements of higher power PA devices. Due to the strong thermal conductivity and heat dissipation capacity, the junction temperature of the chip will not rise, which is beneficial to the long-term reliability of the RF power amplifier device. 4. The thermal expansion coefficient of the diamond composite material layer is significantly lower than that of the CPC, and is closer to the thermal expansion coefficient of the chip, so the alternating thermal stress during temperature cycling is reduced, which is beneficial to the long-term reliability of the packaging structure. 5. The diamond composite material layer is an integrated structure, and the first-level heat sink is eliminated. There is no problem of cracking of the welding layer between the first-level heat sink and the second-level heat sink due to the large mismatch of thermal expansion coefficient between the first-level heat sink and the second-level heat sink, which improves the reliability of the packaging structure of the RF power amplifier device. 6. The one-step welding process is simplified, which shortens the process of the packaging structure of the RF power amplifier, reduces costs, and reduces quality risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application.

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 A schematic diagram of a packaging structure of an embodiment.

[0020] 10. Packaging structure; 100. Chip; 200. Diamond composite material layer; 300. Circuit board; 310. Connecting part; 311. Groove; 400. Adhesive layer; 500. Welding layer. DETAILED DESCRIPTION

[0021] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0022] The packaging structure of existing RF power amplifier devices has problems such as long heat dissipation path, poor heat dissipation effect, large thermal stress between the chip and the first-level heat sink and between the first-level heat sink and the second-level heat sink, poor reliability, complicated process and high quality risk.

[0023] The inventors have found through research and testing that the packaging structure in the prior art is that the LDMOS or GaN chip and the primary heat sink, and the primary heat sink and the secondary heat sink are connected together through welding layers. The primary heat sink is generally a CPC (copper-molybdenum-copper-copper sandwich heat sink), with a thermal conductivity of 200W / mK to 300W / mK and a CTE (thermal expansion coefficient) of 8ppm / K to 11ppm / K; the secondary heat sink is generally copper or aluminum metal, with thermal conductivities of 400W / mK and 237W / mK, and CTEs of 17.5ppm / K and 23ppm / K, respectively. The secondary heat sink is generally embedded in the PCB board as a heat dissipation base.

[0024] However, the packaging structure in the prior art has the following defects: 1. Poor thermal conductivity and heat dissipation capabilities. The thermal conductivity of the primary heat sink (CPC) is only 200W / mK to 300W / mK, while the thermal conductivity of copper is 400W / mK. In the heat dissipation path, the thermal resistance brought by CPC is large, which is difficult to meet the use requirements of higher power PA (radio frequency power amplifier) ​​devices. Moreover, due to insufficient thermal conductivity and heat dissipation capabilities, the junction temperature of the chip will increase, which is not conducive to long-term reliability. 2. Large thermal stress. The CTE of the primary heat sink (CPC) is generally 8ppm / K to 11ppm / K, and the CTE of the semiconductor chip is generally 4ppm / K to 6ppm / K. The mismatch between the two will cause thermal stress due to temperature changes during packaging or use. Under cyclic stress conditions, the life of the device is greatly reduced. 3. The heat dissipation path is long, the interface thermal resistance is large, the process is cumbersome, and the quality and reliability risks are high. After heat is generated from the chip, it passes through the welding layer, the first-level heat sink, the welding layer, and the second-level heat sink, that is, it passes through two welding layers (two weldings). The thermal conductivity of the welding layer (solder) is generally lower than that of the first-level heat sink and the second-level heat sink, which not only affects the heat dissipation, but also brings risks to the process and quality.

[0025] Based on this, the packaging structure 10 and the RF power amplifier device of the following embodiments of the present application are designed and proposed to solve the above-mentioned technical problems.

[0026] like Figure 1 As shown, in one embodiment, a packaging structure 10 is provided, which includes a chip 100, a diamond composite material layer 200 and a circuit board 300, wherein the diamond composite material layer 200 is mounted on the circuit board 300, and the chip 100 is mounted on a side of the diamond composite material layer 200 away from the circuit board 300.

[0027] When the packaging structure 10 in the above embodiment is used, after the secondary heat sink is set as the diamond composite material layer 200 and installed on the circuit board 300, the primary heat sink is cancelled, and the chip 100 is connected to the diamond composite material layer 200 to complete the packaging. Compared with the packaging structure 10 in the prior art, the packaging structure 10 in the present application has at least the following advantages: 1. The diamond composite material layer 200 has a higher thermal conductivity, which increases the thermal conductivity of the secondary heat sink and enhances the thermal conductivity of the packaging structure 10. 2. The primary heat sink is cancelled, which shortens the heat dissipation path of the packaging structure 10 and improves the heat dissipation efficiency of the packaging structure 10. 3. The welding layer 500 between the primary heat sink and the secondary heat sink is cancelled, which reduces the interface thermal resistance of the packaging structure 10, shortens the heat dissipation path, and improves the heat dissipation effect, which can meet the use requirements of higher power PA devices, and because of the strong thermal conductivity and heat dissipation ability, the junction temperature of the chip 100 will not increase, which improves the reliability of the long-term use of the packaging structure 10. 4. The thermal expansion coefficient of the diamond composite material layer 200 is significantly lower than that of the CPC and is closer to that of the chip 100, so the alternating thermal stress during temperature cycling is reduced, which is beneficial to the long-term reliability of the package structure 10. 5. The diamond composite material layer 200 is an integrated structure, and the first-level heat sink is eliminated. There is no problem of cracking of the welding layer 500 between the first-level heat sink and the second-level heat sink due to a large mismatch in thermal expansion coefficients between the first-level heat sink and the second-level heat sink, which improves the reliability of the package structure 10. 6. The one-step welding process is simplified, so that the process of the package structure 10 is shortened, the cost is reduced, and the quality risk is reduced.

[0028] The diamond composite material layer 200 is made of a material mixed with diamond and other metals. Specifically in this embodiment, the diamond composite material layer 200 includes at least one of diamond copper, diamond aluminum, diamond silver and diamond magnesium. The circuit board 300 can be set as a PCB board.

[0029] The thermal conductivity and thermal expansion coefficient of the diamond composite material layer 200 can be flexibly adjusted according to actual needs.

[0030] Optionally, the thermal conductivity of the diamond composite material layer 200 is greater than or equal to 600 W / mK. Thus, compared with the primary heat sink using CPC, the thermal conductivity of the diamond composite material layer 200 in the present application is significantly improved.

[0031] Optionally, the thermal expansion coefficient of the diamond composite material layer 200 is generally greater than or equal to 5 ppm / K and less than or equal to 8 ppm / K. In this way, the thermal expansion coefficient of the diamond composite material layer 200 is obviously close to the thermal expansion coefficient of the chip 100, so the alternating thermal stress during temperature cycling is small, which is beneficial to the long-term reliability of the package structure 10.

[0032] In other embodiments, based on the packaging structure in the prior art, the first heat sink is replaced by CPC with a diamond composite material layer 200, and the thermal expansion coefficient of the diamond composite material layer 200 is adjusted to 8ppm / K to 11ppm / K to keep consistent with the thermal expansion coefficient of CPC. However, at this time, the thermal conductivity of the diamond composite material layer 200 will drop to 500W / mK, and the higher thermal conductivity of the diamond composite material layer 200 cannot be fully utilized.

[0033] like Figure 1 As shown, in one embodiment, the circuit board 300 is provided with a connecting portion 310, and the connecting portion 310 is used to install the diamond composite material layer 200. In this way, the convenience of assembling the packaging structure 10 is improved.

[0034] The connection portion 310 may be provided with a connection socket, a connection slot or other connection structures.

[0035] Specifically in this embodiment, the connection portion 310 is configured as a groove 311, and the diamond composite material layer 200 is embedded in the groove 311. In this way, during the assembly process, the diamond composite material layer 200 can be pressed into the groove 311 under the action of external force, thereby improving the convenience of assembling the package structure 10.

[0036] The number of the grooves 311 , the diamond composite material layer 200 and the chip 100 can be flexibly adjusted according to actual needs.

[0037] Optionally, the package structure 10 further includes an adhesive layer 400, which is filled between the outer wall of the diamond composite material layer 200 and the inner wall of the groove 311 to fix the diamond composite material layer 200 on the circuit board 300. In this way, the circuit board 300 can be connected to the diamond composite material layer 200 as a whole through the adhesive layer 400, thereby improving the reliability of the package structure 10.

[0038] Specifically in this embodiment, the circuit board 300 is pre-filled with solid glue. When the diamond composite material layer 200 is embedded in the groove 311, the circuit board 300 is heated to melt the solid glue. The melted glue flows into the groove 311 to fill the gap between the outer wall of the diamond composite material layer 200 and the inner wall of the groove 311. The glue between the outer wall of the diamond composite material layer 200 and the inner wall of the groove 311 cools and solidifies to form an adhesive layer 400.

[0039] like Figure 1 As shown, in one embodiment, the package structure 10 further includes a welding layer 500, and the welding layer 500 is located between the chip 100 and the diamond composite material layer 200 to fix the chip 100 on the diamond composite material layer 200. In this way, the convenience of assembling the package structure 10 is improved.

[0040] like Figure 1 As shown, optionally, the welding layer 500 is arranged in contact with the chip 100 and the diamond composite material layer 200. In this way, the welding layer 500 is in surface contact with the chip 100 and the diamond composite material layer 200, so that the heat on the chip 100 is transferred to the diamond composite material layer 200 through the welding layer 500, and the thermal conductivity efficiency is enhanced, thereby improving the thermal conductivity and heat dissipation capacity of the packaging structure 10.

[0041] Specifically in this embodiment, the welding layer 500 is fitted with the chip 100 and the diamond composite material layer 200, which means that the contour shape of the welding layer 500 and the chip 100 that are close to each other are adapted to each other, and the contour shape of the welding layer 500 and the diamond composite material layer 200 that are close to each other are adapted to each other.

[0042] In one embodiment, a radio frequency power amplifier device is provided, comprising the packaging structure 10 in any one of the above embodiments.

[0043] When the RF power amplifier device in the above embodiment is used, after the secondary heat sink is set as the diamond composite material layer 200 and installed on the circuit board 300, the primary heat sink is cancelled, and the chip 100 is connected to the diamond composite material layer 200 to complete the package. The RF power amplifier device in the present application has at least the following advantages: 1. The diamond composite material layer 200 has a high thermal conductivity, which increases the thermal conductivity of the secondary heat sink and enhances the thermal conductivity of the RF power amplifier device. 2. The primary heat sink is cancelled, so that the heat dissipation path of the packaging structure 10 is shortened, and the heat dissipation efficiency of the packaging structure 10 is improved. 3. The welding layer 500 between the primary heat sink and the secondary heat sink is cancelled, so that the interface thermal resistance of the packaging structure 10 is reduced, the heat dissipation path is shorter, and the heat dissipation effect is better, which can meet the use requirements of higher power PA devices, and because of the strong thermal conductivity and heat dissipation ability, the junction temperature of the chip 100 will not increase, which is beneficial to the long-term reliability of the RF power amplifier device. 4. The thermal expansion coefficient of the diamond composite material layer 200 is significantly lower than that of the CPC and is closer to that of the chip 100, so the alternating thermal stress during temperature cycling is reduced, which is beneficial to the long-term reliability of the packaging structure 10. 5. The diamond composite material layer 200 is an integrated structure, and the first-level heat sink is eliminated. There is no problem of cracking of the welding layer 500 between the first-level heat sink and the second-level heat sink due to a large mismatch in thermal expansion coefficients between the first-level heat sink and the second-level heat sink, which improves the reliability of the packaging structure 10 of the RF power amplifier device. 6. The one-step welding process is simplified, so that the process of the packaging structure 10 of the RF power amplifier is shortened, the cost is reduced, and the quality risk is reduced.

[0044] In the description of the present application, it should be understood that if 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. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0045] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0046] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0047] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0048] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0049] It should also be understood that when explaining the connection relationship or positional relationship of elements, although not explicitly described, the connection relationship and positional relationship are interpreted as including an error range, which should be within the acceptable deviation range of a specific value determined by those skilled in the art. For example, "approximately", "approximately" or "substantially" may mean within one or more standard deviations, which are not limited here.

[0050] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0051] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A packaging structure, characterized in that: The packaging structure comprises a chip, a diamond composite material layer and a circuit board, wherein the diamond composite material layer is mounted on the circuit board, and the chip is mounted on a side of the diamond composite material layer away from the circuit board; Wherein, the circuit board is provided with a groove, and the diamond composite material layer is embedded in the groove.

2. The packaging structure according to claim 1, characterized in that: The thermal conductivity of the diamond composite material layer is greater than or equal to 600 W / mK.

3. The packaging structure according to claim 1, characterized in that: The thermal expansion coefficient of the diamond composite material layer is greater than or equal to 5 ppm / K and less than or equal to 8 ppm / K.

4. The packaging structure according to claim 1, characterized in that: The packaging structure further includes an adhesive layer, which is filled between the outer wall of the diamond composite material layer and the inner wall of the groove to fix the diamond composite material layer on the circuit board.

5. The packaging structure according to any one of claims 1 to 3, characterized in that: The packaging structure further includes a welding layer, and the welding layer is located between the chip and the diamond composite material layer to fix the chip on the diamond composite material layer.

6. The packaging structure according to claim 5, characterized in that: The welding layer is bonded to the chip and the diamond composite material layer.

7. A radio frequency power amplifier device, characterized in that: Comprising the packaging structure as claimed in any one of claims 1 to 6.

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