阅读说明：本技术 一种新型SiC IGBT器件一体化底板结构 (Novel integrated bottom plate structure of SiC IGBT device ) 是由 叶娜 李萍 于 2020-11-19 设计创作，主要内容包括：本发明涉及SiC IGBT器件的底板,具体为一种新型SiC IGBT器件一体化底板结构。一种新型SiC IGBT器件一体化底板结构,包括底板本体,底板本体的上表面连接有陶瓷基板,陶瓷基板的上表面连接有铜层,底板本体与陶瓷基板间、陶瓷基板与铜层间均通过活性金属钎焊工艺实现连接,形成一体化底板结构。底板本体与陶瓷基板以及陶瓷基板与铜层之间通过活性钎焊工艺连接,熔点由采用的活性金属决定,解决了现有底板与陶瓷覆铜板的焊接层熔点低问题,能有效发挥SiC IGBT器件在178℃以上高温环境中的应用优势；相较于传统的“底板+DBC结构”,去除了DBC下铜层,获得更低的热膨胀系数,更高的热导率,减小了热阻,提高了散热效率。(The invention relates to a bottom plate of a SiC IGBT device, in particular to a novel integrated bottom plate structure of the SiC IGBT device. The utility model provides a novel SiC IGBT device integration floor structure, includes the bottom plate body, the upper surface of bottom plate body is connected with ceramic substrate, and ceramic substrate's upper surface is connected with the copper layer, all realizes being connected through active metal brazing process between bottom plate body and the ceramic substrate, between ceramic substrate and the copper layer, forms integration floor structure. The base plate body is connected with the ceramic substrate and the ceramic substrate is connected with the copper layer through an active brazing process, the melting point is determined by the adopted active metal, the problem that the melting point of the welding layer of the existing base plate and the ceramic copper-clad plate is low is solved, and the application advantage of the SiC IGBT device in a high-temperature environment above 178 ℃ can be effectively exerted; compared with the traditional 'bottom plate + DBC structure', the lower copper layer of the DBC is removed, the lower thermal expansion coefficient is obtained, the higher thermal conductivity is obtained, the thermal resistance is reduced, and the heat dissipation efficiency is improved.)

1. The utility model provides a novel SiC IGBT device integration bottom plate structure, includes bottom plate body (1.1), its characterized in that: the upper surface of the bottom plate body (1.1) is connected with a ceramic substrate (1.2), the upper surface of the ceramic substrate (1.2) is connected with a copper layer (1.3), and the connection between the bottom plate body (1.1) and the ceramic substrate (1.2) and between the ceramic substrate (1.2) and the copper layer (1.3) is realized through an active metal brazing process to form an integrated bottom plate (1) structure.

2. The novel integrated bottom plate structure of the SiC IGBT device according to claim 1, characterized in that: the bottom plate body (1.1) is made of aluminum silicon carbide or copper.

3. The novel integrated bottom plate structure of the SiC IGBT device according to claim 2, characterized in that: the lower surface of the bottom plate body (1.1) has a certain radian, and the upper surface is a plane.

4. The novel SiC IGBT device integrated baseplate structure as claimed in claim 1, 2 or 3, wherein: the ceramic substrate (1.2) is made of aluminum nitride, silicon nitride or aluminum oxide.

5. The novel SiC IGBT device integrated baseplate structure as claimed in claim 1, 2 or 3, wherein: the corner position of the bottom plate body (1.1) is provided with a mounting hole (1.4).

6. The novel SiC IGBT device integrated baseplate structure as claimed in claim 1, 2 or 3, wherein: the ceramic substrate (1.2) is made of aluminum nitride, silicon nitride or aluminum oxide, and mounting holes (1.4) are formed in the corner positions of the bottom plate body (1.1).

7. The novel integrated bottom plate structure of the SiC IGBT device according to claim 3, characterized in that: after the integrated bottom plate is formed, the nano-silver sintering process of the chip is carried out to realize the connection between the integrated bottom plate and the chip.

8. The novel integrated bottom plate structure of the SiC IGBT device according to claim 7, characterized in that: the SiC chip (3) is fixed on a copper layer (1.3) of the integrated base plate (1) through the nano silver sintering layer (2), and the SiC chip (3), the nano silver sintering layer (2) and the base plate (1) jointly form a heat dissipation channel of the SiC IGBT device.

Technical Field

The invention relates to a bottom plate of a SiC IGBT device, in particular to a novel integrated bottom plate structure of the SiC IGBT device.

Background

SiC is used as a third-generation semiconductor material, and the forbidden band width is 3 times of that of a Si material, so that the SiC can work at higher temperature; the critical breakdown electric field is 10 times of that of the Si material, so that the Si material can meet the higher voltage requirement; the thermal conductivity is 3 times that of the Si material, so that the material has lower junction-to-shell thermal resistance. Particularly, in recent years, the quality of SiC crystals and the process technology of SiC devices are mature day by day, so that the SiC crystals become ideal materials for preparing novel high-power low-power-consumption power electronic devices. However, limited by the packaging technology, the packaging of the SiC IGBT device still adopts the packaging form of the Si-based power device, and is composed of components such as a bottom plate, a ceramic copper clad laminate (DBC), an electrode, a top cover, and a housing, wherein the bottom plate and the ceramic copper clad laminate are connected by a soldering lug in a vacuum reflow soldering manner.

In the packaging process of the Si-based IGBT device, the Si chip is connected with the ceramic copper-clad plate in the first step, an intermetallic compound with the thickness of 1-3 mu m is formed by welding a lead-tin-silver (PbSnAg) soldering lug to realize the connection between the silicon chip and the DBC, and the melting point of the soldering lug is 280 ℃; and in the second step, a lead-tin-silver soldering lug (PbSnAg) with different components is adopted on the lower surface of the copper-clad layer of the base plate and the DBC to perform vacuum reflow soldering to form an intermetallic compound with the thickness of 1-3 mu m so as to realize the connection between the base plate and the DBC, and the melting point of the soldering lug is 178 ℃.

The packaging of the SiC-based IGBT device still adopts the packaging form of a Si-based power device, the welding quality of the base plate and the ceramic copper-clad plate can obviously influence the heat transfer efficiency, and if a welding cavity exists, the thermal resistance can be obviously increased because the heat conduction coefficient of air is far lower than the heat transfer coefficient of metal solder; meanwhile, the welding area of the bottom plate and the ceramic copper-clad plate is large, and the vacuum reflow soldering process is complex and difficult to control. The SiC chip and the ceramic copper-clad plate are connected by adopting a nano-silver sintering process, the melting point is more than 900 ℃, but the melting point of the welding layer of the base plate and the ceramic copper-clad plate is usually 178 ℃. When the SiC-based IGBT device works in a high-temperature environment of more than 200 ℃, a welding layer of the base plate and the ceramic copper-clad plate is melted, the use of the SiC-based IGBT device under a high-temperature condition is severely limited, and the advantage of the high-temperature characteristic of the SiC IGBT device is difficult to exert.

Disclosure of Invention

Aiming at the problem that in the existing SiC IGBT device packaging process, a baseplate and a subunit ceramic copper-clad plate still adopt vacuum reflow soldering in a silicon-based IGBT device packaging mode, and the melting point of a welding layer is 178 ℃; when the SiC-based IGBT device works in a high-temperature environment of more than 200 ℃, the welding layer of the base plate and the ceramic copper-clad plate can be melted, so that the SiC-based IGBT device fails and the advantage of the high-temperature characteristic of the SiC IGBT device is difficult to be exerted. According to the invention, by designing the integrated SiC IGBT device baseplate structure, adopting an active metal brazing process (AMB), and canceling a vacuum reflow soldering process of solder between the baseplate and the subunit, the problem of solder melting when the integrated SiC IGBT device baseplate structure is applied under a high-temperature condition is avoided.

The invention is realized by adopting the following technical scheme: the utility model provides a novel SiC IGBT device integration floor structure, includes the bottom plate body, the upper surface of bottom plate body is connected with ceramic substrate, and ceramic substrate's upper surface is connected with the copper layer, all realizes being connected through active metal brazing process between bottom plate body and the ceramic substrate, between ceramic substrate and the copper layer, forms integration floor structure. The base plate body is connected with the ceramic substrate and the ceramic substrate is connected with the copper layer through an active brazing process, the melting point is determined by the adopted active metal, the problem that the melting point of the welding layer of the existing base plate and the existing ceramic copper-clad plate is low is solved, and the application advantage of the SiC IGBT device in a high-temperature environment above 178 ℃ can be effectively played.

Foretell novel SiC IGBT device integration bottom plate structure, the material of bottom plate body is aluminium carborundum or copper.

Foretell novel SiC IGBT device integration bottom plate structure, bottom plate body lower surface has certain radian, and the upper surface is the plane.

In the novel integrated bottom plate structure of the SiC IGBT device, the ceramic substrate is made of aluminum nitride, silicon nitride or aluminum oxide.

Foretell novel SiC IGBT device integration bottom plate structure, the corner position of bottom plate body is provided with the mounting hole.

Foretell novel SiC IGBT device integration bottom plate structure, ceramic substrate material are aluminium nitride, silicon nitride or aluminium oxide, and the corner position of bottom plate body is provided with the mounting hole.

According to the novel SiC IGBT device integrated bottom plate structure, the integrated bottom plate is formed, and then the nano-silver sintering process of the chip is carried out, so that the integrated bottom plate is connected with the chip.

According to the novel integrated base plate structure of the SiC IGBT device, the SiC chip is fixed on the copper layer of the integrated base plate through the nano silver sintering layer, and the SiC chip, the nano silver sintering layer and the base plate jointly form a heat dissipation channel of the SiC IGBT device.

The invention provides a novel integrated bottom plate structure of a SiC IGBT device, which can effectively reduce the thermal resistance from a chip to the bottom plate, improve the heat dissipation efficiency, simultaneously reduce the difficulty of the packaging process of the SiC IGBT device, improve the production efficiency, solve the problem that the application in a high-temperature environment higher than 178 ℃ is difficult due to the low melting point of a welding layer of the bottom plate and a ceramic copper-clad plate, and is beneficial to exerting the advantage of the high-temperature characteristic of the SiC IGBT device.

Drawings

Fig. 1 is a schematic structural diagram of an integrated bottom plate.

Fig. 2 is a schematic diagram of a SiC IGBT device package.

In the figure: 1.1: bottom plate body, 1.2: ceramic substrate, 1.3: copper layer, 1.4: and (7) installing holes.

1: integrated bottom plate, 2: nano silver sintered layer, 3: and (3) a SiC chip.

Detailed Description

The invention provides a novel integrated bottom plate structure of a SiC IGBT device, which can effectively reduce the thermal resistance between a chip and a bottom plate, improve the heat dissipation efficiency, simultaneously reduce the difficulty of the packaging process of the SiC IGBT device, improve the production efficiency, solve the problem that the welding layer of the bottom plate and a ceramic copper-clad plate can not be applied at a high temperature of more than 178 ℃ due to low melting point, and is beneficial to exerting the advantage of the high-temperature characteristic of the SiC IGBT device.

As shown in fig. 1, a novel SiC IGBT device integrated bottom plate structure is composed of a bottom plate body 1.1, a ceramic substrate 1.2, a copper layer 1.3, and a mounting hole 1.4. The bottom plate body is made of aluminum silicon carbide or copper, the lower surface of the bottom plate body is provided with a certain radian, and the upper surface of the bottom plate body is a plane. The ceramic substrate is made of aluminum nitride, silicon nitride or aluminum oxide. The high-temperature metallurgical bonding connection is realized between the bottom plate body 1.1 and the ceramic substrate 1.2 and between the ceramic substrate 1.2 and the copper layer 1.3 through an active metal brazing process, so that an integrated bottom plate structure is formed. And after the integrated bottom plate is formed, the nano-silver sintering process of the chip is carried out to realize the connection between the integrated bottom plate and the chip.

As shown in fig. 2, the SiC chip 3 is fixed on the copper layer of the integrated bottom plate 1 through the nano silver sintered layer 2, and the SiC chip 3, the nano silver sintered layer 2 and the bottom plate 1 together form a heat dissipation channel of the SiC IGBT device.

Compared with the traditional SiC device, the novel SiC IGBT device bottom plate structure provided by the invention has the following advantages:

(1) compared with the traditional bottom plate + DBC structure, the integrated bottom plate structure removes a lower copper layer of the DBC (the traditional DBC structure comprises a lower copper layer, a middle ceramic layer and an upper copper layer) and a welding layer structure between the lower copper layer of the DBC and the bottom plate, obtains a lower thermal expansion coefficient and a higher thermal conductivity, reduces the thermal resistance and improves the heat dissipation efficiency; and simultaneously, the manufacturing cost of the DBC is reduced.

(2) Compared with the traditional SiC device packaging process, the complex DBC and bottom plate are omitted during packaging

The welding process greatly reduces the difficulty of the packaging process of the SiC IGBT device, improves the production efficiency and reduces the production cost.

(3) Because the base plate body is connected with the ceramic substrate and the ceramic substrate is connected with the copper layer through the active brazing process, the melting point is determined by the adopted active metal, the problem that the melting point of the welding layer of the existing base plate and the ceramic copper-clad plate is low is solved, and the application advantage of the SiC IGBT device in a high-temperature environment above 178 ℃ can be effectively exerted.