Silicon carbide patch type ceramic diode

Abstract

The utility model relates to the technical field of power electronic silicon stack devices, in particular to a silicon carbide patch type ceramic diode. Comprising a ceramic shell, a silicon carbide chip, a lead-in electrode, a lead-out electrode, a copper-clad substrate and a bonding copper sheet, the silicon carbide chips are fixedly connected to the copper-clad substrates, the multiple copper-clad substrates are distributed in a matrix mode, the ceramic shell is of a rectangular box structure with an opening, grooves corresponding to the copper-clad substrates are formed in the inner bottom face of the ceramic shell, and the copper-clad substrates are embedded into the grooves. The leading-in electrode and the leading-out electrode are fixedly connected to the two sides of the copper-clad substrate matrix and connected with the copper-clad substrate and the silicon carbide chip through the bonding copper sheets. And the copper-clad substrates are connected through bonding copper sheets. The heat conductivity can be improved, the packaging process is simplified, and the overall performance is improved.

Description

A silicon carbide surface-mount ceramic diode Technical Field

[0001] This utility model relates to the field of silicon stack device technology, specifically a silicon carbide surface-mount ceramic diode. Background Technology

[0002] Silicon stack devices typically refer to composite devices composed of multiple silicon-based semiconductor devices (such as diodes, thyristors, etc.) connected in series or parallel, used in high-voltage or high-current scenarios.

[0003] However, existing silicon-based devices use silicon-based materials, which have poor thermal conductivity (≤150W / m·K) and are prone to thermal runaway at high temperatures, resulting in short device lifespan and low reliability. Ceramic diodes are widely used under high voltage and high temperature conditions, but traditional ceramic diodes suffer from problems such as low thermal conductivity and complex packaging.

[0004] Silicon carbide (S) i C) As a wide bandgap semiconductor material, silicon carbide possesses significant advantages over traditional silicon-based materials, including a larger bandgap, higher breakdown electric field strength, higher thermal conductivity, and faster electron saturation drift velocity. Surface mount diodes based on silicon carbide, with their small size, high power density, fast switching speed, and resistance to high temperature and high pressure, are widely used in new energy vehicles, photovoltaic power generation, rail transportation, smart grids, and high-frequency power supplies. Summary of the Invention

[0005] To overcome the shortcomings of the existing technology, this utility model provides a silicon carbide surface-mount ceramic diode, which can improve thermal conductivity, simplify the packaging process, and improve overall performance.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A silicon carbide surface-mount ceramic diode includes a ceramic housing, a silicon carbide chip, an input electrode, an output electrode, a copper-clad substrate, and bonding copper sheets. The silicon carbide chip is fixed to the copper-clad substrate, and multiple copper-clad substrates are arranged in a matrix. The ceramic housing is an open rectangular box structure, and the bottom surface of the ceramic housing has grooves corresponding to the copper-clad substrates, into which the copper-clad substrates are embedded. The input electrode and the output electrode are fixed to both sides of the copper-clad substrate matrix and connected to the copper-clad substrate and the silicon carbide chip through bonding copper sheets. The copper-clad substrates are connected to each other through bonding copper sheets.

[0008] Furthermore, the outer surface of the ceramic shell is uniformly covered with strip-shaped grooves to form heat dissipation fins.

[0009] Furthermore, the silicon carbide chip surface is covered with a passivation layer, and grooves are provided at the edges.

[0010] Furthermore, the introduced electrode and the led-out electrode have the same structure, which is a plate with two 90-degree bends, and a boss is provided on the bottom surface of the inner side of the ceramic shell, with one end of the plate fixed to the boss.

[0011] Furthermore, the bonding copper sheet is stepped, with a raised center and edges on both sides.

[0012] Compared with the prior art, the present invention has at least the following technical effects or advantages:

[0013] 1. This utility model features an embedded copper-clad substrate design. A rectangular groove is provided inside the ceramic shell to embed the copper-clad substrate, shortening the heat conduction path, improving thermal conductivity, and simplifying the packaging process. Introducing and leading electrodes are fixed to both sides of the copper-clad substrate matrix and connected to the copper-clad substrate and silicon carbide chip via bonding copper sheets. The copper-clad substrates are also connected to each other via bonding copper sheets. The bonding copper sheets have been optimized, employing pre-formed copper sheets and ultrasonic bonding technology to enhance the connection strength between the silicon carbide chip and the copper-clad substrate.

[0014] 2. The outer surface of the ceramic shell of this invention features evenly distributed strip-shaped grooves, forming wave-shaped heat dissipation fins. By expanding the effective heat dissipation area of ​​the ceramic shell, the heat transfer from the inside of the device to the outside air is accelerated, reducing thermal resistance and improving heat dissipation efficiency.

[0015] 3. The silicon carbide chip of this invention has a passivation layer covering its surface and trenches along its edges. The passivation layer (such as SiO2, Si3N4, or Al2O3) covers the silicon carbide chip. i The C-chip surface is designed to suppress surface leakage current, prevent environmental corrosion, and optimize the electric field distribution. Grooves at the edges reduce on-resistance and enhance thermal stability. The synergistic effect of the passivation layer and the trenches suppresses interface breakdown, optimizes dynamic characteristics, and improves long-term reliability.

[0016] 4. The bonding copper sheet of this utility model is stepped, with a raised center and edges on both sides. The stepped layout reduces current path impedance. Attached Figure Description

[0017] Figure 1 is a three-dimensional structural diagram of this utility model.

[0018] Figure 2 is a three-dimensional structural diagram of this utility model from another angle.

[0019] Figure 3 is a schematic diagram of the three-dimensional structure of the ceramic shell of this utility model.

[0020] Figure 4 is a three-dimensional structural diagram of this utility model (excluding the ceramic shell).

[0021] Figure 5 is a three-dimensional structural diagram of this utility model from another angle (excluding the ceramic shell).

[0022] In the figure: 1. Ceramic shell; 2. Silicon carbide chip; 3. Lead-in electrode; 4. Lead-out electrode; 5. Copper-clad substrate; 6. Bonded copper sheet; 11. Groove; 12. Heat dissipation fin; 13. Boss; 31. First plate; 32. Vertical plate; 33. Second plate; 34. Plug hole; 35. Weight reduction heat dissipation hole. Detailed Implementation

[0023] The embodiments of this utility model are described in detail below. To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this utility model or its application or use. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0024] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0025] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0026] In the description of this utility model, it should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this utility model. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0027] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0028] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this utility model.

[0029] As shown in Figures 1-5, a silicon carbide surface-mount ceramic diode includes a ceramic housing 1, a silicon carbide chip 2, an input electrode 3, an output electrode 4, a copper-clad substrate 5, and a bonding copper sheet 6.

[0030] As shown in Figures 2 and 3, the ceramic shell 1 is made of high thermal conductivity aluminum nitride ceramic material and has a rectangular box structure with an open top. The bottom surface of the ceramic shell 1 has a rectangular groove 11 corresponding to the copper-clad substrate 5, and the copper-clad substrate 5 is embedded in the groove 11. The left and right sides of the bottom surface of the ceramic shell 1 have rectangular protrusions 13 corresponding to the lead-in electrode 3 and the lead-out electrode 4. The lead-in electrode 3 is fixed to the right side of the ceramic shell 1, and the lead-out electrode 4 is fixed to the left side of the ceramic shell 1.

[0031] The bottom outer surface of the ceramic housing 1 is evenly distributed with rectangular grooves, which serve as wave-shaped heat dissipation fins 12. By expanding the effective heat dissipation area of ​​the ceramic housing, the heat transfer from the inside of the device to the outside air is accelerated, the thermal resistance is reduced, and the heat dissipation efficiency is improved.

[0032] As shown in Figures 4 and 5, the surface of the silicon carbide chip 2 is covered with a passivation layer, and trenches are provided at the edges. The passivation layer (such as SiO2, Si3N4, or Al2O3) covering the surface of the SiC chip can suppress surface leakage current, prevent environmental corrosion, and optimize the electric field distribution. The trenches at the edges can reduce the on-resistance and enhance thermal stability. The synergistic effect of the passivation layer and the trenches can suppress interface breakdown, optimize dynamic characteristics, and improve long-term reliability.

[0033] Electrode 3 and electrode 4 have the same structure and are made of gold-plated copper. They are connected to the external circuit via SMT (Surface Mount Technology). The circuit consists of two 90-degree bent boards, comprising a first flat plate 31, a vertical plate 32, and a second flat plate 33. The ends of the vertical plate 32 are perpendicular to both the first flat plate 31 and the second flat plate 33. The first flat plate 31 is fixed to the rectangular boss 13 of the ceramic housing 1, the second flat plate 33 is fixed to the upper surface of the ceramic housing 1, and the vertical plate 32 is fixed to the inner wall of the ceramic housing 1. The first flat plate 31 has plug solder holes 34, and the second flat plate 33 has weight-reducing heat dissipation holes 35.

[0034] The copper-clad substrate 5 is rectangular with a copper layer thickness of 50-100μm. The copper-clad substrate 5 is embedded in the groove 11 and connected to the ceramic shell 1 by laser welding. The copper-clad substrate 5 serves as a lead electrode.

[0035] The bonding copper sheet 6 is stepped, with a raised center and edges on both sides. The stepped layout of the bonding copper sheet 6, serving as the bonding electrode, reduces current path impedance.

[0036] As shown in Figures 1, 4, and 5, multiple copper-clad substrates 5 are arranged in a matrix. In this embodiment, there are a total of 18 copper-clad substrates 5, arranged in three rows and six columns. The silicon carbide chip 2 is formed by pre-formed copper sheets coated with silver paste and hot-pressed at 300°C. The silicon carbide chip 2 is soldered onto the copper-clad substrates 5, with one silicon carbide chip 2 soldered onto each copper-clad substrate 5. The three copper-clad substrates 5 in each column are connected by two vertical bonding copper sheets 6, and the six copper-clad substrates 5 in each row are connected end to end by five horizontal bonding copper sheets 6. One edge of the bonding copper sheet 6 is fixed to the copper-clad substrate 5, and the other edge is fixed to the silicon carbide chip 2.

[0037] The lead-in electrode 3 and the lead-out electrode 4 are fixed on both sides of a matrix composed of multiple copper-clad substrates 5. The lead-in electrode 3 and the lead-out electrode 4 are connected to the copper-clad substrates 5 through bonding copper sheets 6.

[0038] The preparation process of this utility model is as follows:

[0039] Step 1: Ceramic shell 1 machining (CNC engraving to form heat dissipation fins and groove structure).

[0040] Step 2: Pre-soldering of copper-clad substrate 5 (the copper layer is fixed in the ceramic groove by vacuum brazing process).

[0041] Step 3: Silicon carbide chip 2 bonding (pre-formed copper sheet coated with silver paste, hot-pressed and bonded at 300℃).

[0042] Step 4: Resin encapsulation (epoxy resin fills the gaps, and the surface is polished after curing).

[0043] This invention employs a copper-clad substrate embedded design, with a rectangular groove 11 inside the ceramic shell 1 to embed the copper-clad substrate 5, thereby shortening the heat conduction path. Optimized copper bonding is achieved through the use of pre-formed copper sheets and ultrasonic bonding technology, enhancing the connection strength between the silicon carbide chip 2 and the copper-clad substrate 5.

[0044] This invention can improve thermal conductivity, simplify the packaging process, and improve overall performance.

[0045] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A silicon carbide surface-mount ceramic diode, characterized in that: The device includes a ceramic shell, a silicon carbide chip, lead-in electrodes, lead-out electrodes, a copper-clad substrate, and bonding copper sheets. The silicon carbide chip is fixed to the copper-clad substrate, and multiple copper-clad substrates are arranged in a matrix. The ceramic shell is an open rectangular box structure, and the bottom surface of the ceramic shell has a groove corresponding to the copper-clad substrate, into which the copper-clad substrate is embedded. The lead-in electrodes and lead-out electrodes are fixed to both sides of the copper-clad substrate matrix and are connected to the copper-clad substrate and the silicon carbide chip through bonding copper sheets. The copper-clad substrates are connected to each other through bonding copper sheets.

2. The silicon carbide surface-mount ceramic diode according to claim 1, characterized in that: The outer surface of the ceramic shell is evenly distributed with strip-shaped grooves to form heat dissipation fins.

3. A silicon carbide surface-mount ceramic diode according to claim 1, characterized in that: The silicon carbide chip has a passivation layer on its surface and grooves along its edges.

4. A silicon carbide surface-mount ceramic diode according to claim 1, characterized in that: The inlet electrode and outlet electrode have the same structure, consisting of two plates with 90-degree bends. The bottom surface inside the ceramic shell has a boss, and one end of the plate is fixed to the boss.

5. A silicon carbide surface-mount ceramic diode according to claim 1, characterized in that: The bonding copper sheet is stepped, with a raised center and edges on both sides.

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