SMD (Surface Mounted Device) ceramic packaging tube shell adaptive to high-current chip

Abstract

According to the technical scheme, the SMD ceramic packaging tube shell matched with the large-current chip comprises a ceramic piece, metalized areas are arranged on the two sides of the ceramic piece, an enclosure frame and an upper electrode plate are welded to the metalized area on one side of the ceramic piece, and the upper electrode plate is welded to the enclosure frame. A heat sink and a lower electrode plate are welded on the metalized area on the other side of the ceramic piece, and the upper electrode plate and the lower electrode plate are connected through a connecting conductive column penetrating through the ceramic piece. According to the utility model, the upper electrode plate, the enclosure frame, the lower electrode plate and the heat sink are respectively welded on two sides of the ceramic piece, so that the limitation of welding of the ceramic piece and the electrodes on a bonding area in a traditional structure is avoided, and meanwhile, the electrode state is changed from boss or metal slurry through hole conduction to conductive column connection, so that the resistance is reduced, and the overcurrent capability is improved; according to the utility model, the dielectric withstand voltage test of 3000V can be borne, and the requirements of the maximum continuous current of 118A and the pulse current of 400A can be met, so that the high-current chip can be adapted.

Description

Technical Field

[0001] The utility model relates to the technical field of SMD ceramic packaging, in particular to an SMD ceramic packaging shell adapted to high-current chips. Background Technique

[0002] SMD ceramic packaging belongs to a type of hermetic packaging and is one of the main packaging technologies for high-reliability requirements. Its main materials include alumina, beryllium oxide, aluminum nitride, etc. Such ceramic shells use HTCC or LTCC ceramics as circuit substrates, with internal metallized vias or side metallization conduction, and then use metal parts to achieve isolation, airtightness, and heat dissipation functions.

[0003] Existing SMD ceramic shells generally consist of ceramic parts, sealing rings, heat sinks, and electrodes. Among them, the electrodes are mostly directly brazed at the bottom in the shape of bosses or filled with metal paste in the ceramic parts for hole filling, and upper and lower welding electrode plates are used for conduction. However, neither of these two schemes can meet the usage scenarios of high-voltage and high-current chip packaging. Under the impact of continuous high current, obvious leakage increase or arcing phenomena will occur, resulting in packaging failure. Content of the Utility Model

[0004] Aiming at the deficiencies of the existing technology, the purpose of the utility model is to provide an SMD ceramic packaging shell adapted to high-current chips.

[0005] In order to achieve the above purpose, the technical solution of the utility model is as follows:

[0006] An SMD ceramic packaging shell adapted to high-current chips, including a ceramic part. Metallized areas are provided on both sides of the ceramic part. A surrounding frame and an upper electrode plate are welded on the metallized area on one side of the ceramic part. A heat sink and a lower electrode plate are welded on the metallized area on the other side of the ceramic part. And the upper electrode plate and the lower electrode plate are connected by connecting conductive columns penetrating the ceramic part.

[0007] Preferably, the metallized area of the ceramic part is set as tungsten paste plated with nickel, and the thickness of the nickel layer is set to 0.6 - 2.0 um.

[0008] Preferably, the connecting conductive columns are set as copper columns, and the connecting conductive columns are specifically copper columns made of TU1.

[0009] Preferably, the diameter tolerance between the holes of the ceramic part for accommodating the connecting conductive columns and the connecting conductive columns is not greater than 0.04 mm.

[0010] Preferably, the heat sink is set as a bottom plate made of WCu alloy, and the heat sink is specifically a bottom plate made of W85Cu15.

[0011] Preferably, the surface of the heat sink is plated with nickel, and the thickness of the nickel layer is 0.6 - 2.0 um.

[0012] Preferably, the surrounding frame is made of a kovar metal and is specifically a frame made of 4J29 alloy. The upper electrode plate and the lower electrode plate are both electrode plates made of kovar metal and are specifically electrode plates made of 4J42 alloy.

[0013] Preferably, silver-copper solder sheets are placed between the ceramic component, the heat sink and the lower electrode plate, and between the ceramic component, the surrounding frame and the upper electrode plate. The thickness of the silver-copper solder sheet is set to be 0.03 - 0.2 mm.

[0014] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0015] In the present utility model, by welding the upper electrode plate and the surrounding frame to the lower electrode plate and the heat sink on both sides of the ceramic component respectively, the limitation of the bonding area caused by the welding of the ceramic component and the electrode in the traditional structure is avoided. At the same time, by changing the electrode state from conduction through a boss or a metal paste through hole to a copper column connection, the resistance is reduced, the over-current capacity is increased, and it can withstand a dielectric withstand voltage test of 3000V and can meet the requirements of a maximum continuous current of 118A and a pulse current of 400A. Furthermore, it is adapted to high-current chips and the applicable range is increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The disclosure of the present utility model will be described with reference to the accompanying drawings. It should be understood that the drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present utility model. In the drawings, the same reference numerals are used to refer to the same components.

[0017] Among them:

[0018] Figure 1 is a schematic diagram of the overall structure of the present utility model;

[0019] Figure 2 is a top view of the present utility model;

[0020] Figure 3 is a bottom view of the present utility model.

[0021] The reference numerals in the drawings are explained as follows: 1. Surrounding frame; 2. Ceramic component; 3. Heat sink;

[0022] 4. Lower electrode plate; 5. Upper electrode plate; 6. Connecting conductive column. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] It is easy to understand that according to the technical solution of the present utility model, without changing the essential spirit of the present utility model, those of ordinary skill in the art can propose various interchangeable structural forms and implementation methods. Therefore, the following specific embodiments and the accompanying drawings are only illustrative descriptions of the technical solution of the present utility model, and should not be regarded as the whole of the present utility model or as a limitation or restriction on the technical solution of the present utility model.

[0024] As Figure 1 shown, as an SMD ceramic package housing adapted to a high-current chip of the present utility model, it includes a surrounding frame 1, a ceramic part 2, a heat sink 3, a lower electrode plate 4 and an upper electrode plate 5. Metallized areas are provided on both sides of the ceramic part 2. The metallized area of the ceramic part 2 is set as nickel plating on the tungsten paste surface, and the thickness of the nickel layer is set to 1um. As Figure 2 shown, the surrounding frame 1 and the upper electrode plate 5 are welded on the metallized area on one side of the ceramic part 2 through silver-copper solder. As Figure 3 shown, the heat sink 3 and the lower electrode plate 4 are welded on the metallized area on the other side of the ceramic part 2 through silver-copper solder. The nickel layer is beneficial to the welding work. By welding the upper electrode plate 5 and the surrounding frame 1 and the lower electrode plate 4 and the heat sink 3 on both sides of the ceramic part 2 respectively, the limitation of the bonding area caused by the welding of the ceramic part 2 and the electrode in the traditional structure is avoided.

[0025] As Figure 1 shown, holes are provided in the ceramic part 2, and connecting conductive columns 6 are arranged in the holes. The upper electrode plate 5 and the lower electrode plate 4 are connected through the connecting conductive columns 6 passing through the holes in the ceramic part 2. By changing the electrode state from a boss or a metal paste through-hole conduction to the connection of the connecting conductive columns 6, the resistance is reduced, the over-current capacity is increased, and it can withstand a dielectric withstand voltage test of 3000V and can meet the requirements of a maximum continuous current of 118A and a pulse current of 400A. Furthermore, it is adapted to a high-current chip, increasing the scope of application. The connecting conductive columns 6 are set as copper columns, and the connecting conductive columns 6 are specifically set as copper columns made of TU1. The conductive performance of the connecting conductive columns 6 is ensured by the copper columns. At the same time, the conductive performance of the connecting conductive columns 6 is further ensured by the characteristics of extremely low oxygen and impurity content of TU1. The diameter tolerance between the holes in the ceramic part 2 for accommodating the connecting conductive columns 6 and the connecting conductive columns 6 is 0.02mm. On the one hand, the welding strength of the product is ensured by the diameter tolerance, and on the other hand, the airtightness of the welding work is ensured.

[0026] The heat sink 3 is set as a bottom plate made of WCu alloy, and the heat sink 3 is specifically set as a bottom plate made of W85Cu15. The heat sink 3 made of W85Cu15 improves the heat dissipation performance of the product, which is beneficial to increasing the service life of the product. The surface of the heat sink 3 is nickel-plated by chemical plating or electroplating, and the thickness of the nickel layer is 1um. The nickel layer is beneficial to the welding work.

[0027] The surrounding frame 1 is set as a frame made of kovar metal, and specifically, the surrounding frame 1 is set as a frame made of 4J29 alloy. The stability of the product is ensured by the fact that the 4J29 alloy has a linear expansion coefficient similar to that of borosilicate hard glass. The upper electrode plate 5 and the lower electrode plate 4 are both electrode plates made of kovar metal, and specifically, the upper electrode plate 5 and the lower electrode plate 4 are set as electrode plates made of 4J42 alloy. The stability of the product is ensured by the fact that the 4J42 alloy has a low thermal expansion coefficient, good mechanical properties and corrosion resistance.

[0028] Silver-copper solder sheets are placed between the ceramic component 2, the heat sink 3 and the lower electrode plate 4, and between the ceramic component 2, the surrounding frame 1 and the upper electrode plate 5. The thickness of the silver-copper solder sheet is set to 0.1 mm, and the soldering work is completed by melting the silver-copper solder sheet and then flowing the solder.

[0029] During use, after the heat sink 3 and the lower electrode plate 4 are fixed with a fixture, a silver-copper solder sheet is placed between the ceramic component 2, the heat sink 3 and the lower electrode plate 4, a connecting conductive column 6 is placed in the ceramic component 2, a silver-copper solder sheet is placed between the ceramic component 2, the surrounding frame 1 and the upper electrode plate 5, and the temperature is raised in a brazing furnace until the silver-copper solder sheet melts, and the soldering work is completed by flowing the solder.

[0030] The technical scope of the present utility model is not limited to the content described above. Those skilled in the art can make various deformations and modifications to the above embodiments without departing from the technical idea of the present utility model, and these deformations and modifications should all fall within the protection scope of the present utility model.

Claims

1. An SMD ceramic package housing adapted for high-current chips, characterized in that: It includes a ceramic component (2). Metallized areas are provided on both sides of the ceramic component (2). A surrounding frame (1) and an upper electrode plate (5) are welded on the metallized area on one side of the ceramic component (2), and a heat sink (3) and a lower electrode plate (4) are welded on the metallized area on the other side of the ceramic component (2). The upper electrode plate (5) and the lower electrode plate (4) are connected by a connecting conductive column (6) passing through the ceramic component (2).

2. The SMD ceramic package housing adapted to a high-current chip according to claim 1, wherein: The metallized area of the ceramic component (2) is set as nickel-plated tungsten paste, and the thickness of the nickel layer is set to be 0.6 - 2.0 um.

3. The SMD ceramic package case adapted to a high-current chip according to claim 1, wherein: The connecting conductive column (6) is set as a copper column, and the connecting conductive column (6) is specifically a copper column made of TU1.

4. The SMD ceramic package case adapted to a large-current chip according to claim 3, characterized in that: The diameter tolerance of the hole in the ceramic component (2) for accommodating the connecting conductive column (6) and the connecting conductive column (6) is not greater than 0.04 mm.

5. The SMD ceramic package housing adapted to a high-current chip according to claim 1, wherein: The heat sink (3) is set as a bottom plate made of WCu alloy, and the heat sink (3) is specifically a bottom plate made of W85Cu15.

6. The SMD ceramic package case adapted to a high-current chip according to claim 5, wherein: The surface of the heat sink (3) is nickel-plated, and the thickness of the nickel layer is 0.6 - 2.0 um.

7. The SMD ceramic package housing adapted to a high-current chip according to claim 1, wherein: The surrounding frame (1) is set as a frame made of kovar metal, and the surrounding frame (1) is specifically a frame made of 4J29 alloy. The upper electrode plate (5) and the lower electrode plate (4) are both electrode plates made of kovar metal, and the upper electrode plate (5) and the lower electrode plate (4) are specifically electrode plates made of 4J42 alloy.

8. The SMD ceramic package case adapted to a high-current chip according to claim 1, wherein: A silver-copper solder sheet is placed between the ceramic component (2), the heat sink (3) and the lower electrode plate (4). A silver-copper solder sheet is placed between the ceramic component (2), the surrounding frame (1) and the upper electrode plate (5), and the thickness of the silver-copper solder sheet is set to be 0.03 - 0.2 mm.

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