SMD ceramic packaging shell structure

Abstract

The utility model discloses an SMD ceramic packaging shell structure which is suitable for small SMD ceramic packaging of a low-resistance high-power chip, an electrode is divided into an inner polar plate and an outer polar plate, a through hole is processed on a ceramic base, tungsten slurry is printed on the hole wall, silver-copper solder is filled in the through hole, and when the inner polar plate and the outer polar plate are welded on the upper surface and the lower surface of the through hole, the inner polar plate and the outer polar plate are welded on the inner polar plate and the outer polar plate. And the welding flux is adsorbed on the hole wall of the through hole after being melted, so that the risk of air leakage after a polar plate is welded can be effectively reduced under the condition that the boundary dimension of the SMD ceramic shell is small, the requirements of low resistance and high power are met, and the product percent of pass is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of ceramic shell structures of chip packaging, specifically to a kind of SMD (Surface Mounted Devices) ceramic packaging shell structure. BACKGROUND

[0002] SMD ceramic shell is welded by high thermal conductivity electrode, metal sealing ring and ceramic base, belongs to surface mount power device, and is applied in semiconductor integrated circuit, hybrid integrated circuit and other devices.

[0003] At present, to meet the low resistance large power requirement of power device, the high thermal conductivity electrode used by SMD ceramic shell is usually made into boss type, welded in the lower surface of ceramic base, and the boss penetrates through the whole ceramic base, so that the lead-out end on chip can be connected with the top surface of metal electrode of boss type by bonding wire bonding method, so that chip is connected with external circuit through the metal electrode of lower surface of ceramic shell, to complete electrical connection and realize heat conduction.

[0004] However, for small SMD ceramic shell, due to the small size of shell, if electrode is made into boss type, it is difficult to process and the cost is high, and the effective area of electrode welding is small, which greatly increases the risk of gas leakage, and the welding surface is small when used by user, so that thick copper wire cannot be bonded. If the small hole filled with tungsten slurry on the ceramic base is connected with the external metal part, it cannot meet the requirement of low resistance large power and cannot dissipate heat. SUMMARY

[0005] The utility model discloses a kind of ceramic shell structures of chip packaging, specifically to a kind of SMD (Surface Mounted Devices) ceramic packaging shell structure.

[0006] Technical scheme: a kind of SMD ceramic packaging shell structure, comprising: ceramic base, several inner plates, outer plate;The number of inner plates is consistent with the pin number of the packaged chip, the inner plate is distributed on the upper surface of ceramic base, and the outer plate is distributed on the lower surface of ceramic base;The inner plate and the outer plate are arranged oppositely one by one, and a through hole is provided on the ceramic base at the opposite position, and tungsten slurry is printed on the hole wall of the through hole;The through hole is filled with silver copper solder, and the opposite inner plate and outer plate are welded at the upper and lower ends of the through hole, and the silver copper solder is adsorbed on the hole wall of the through hole after melting when plate is welded.

[0007] Further, the ceramic base is provided with a core cavity for accommodating the chip, and the lower surface of the ceramic base is welded with a heat sink covering the bottom of the core cavity.

[0008] Further, the upper surface of the ceramic base is welded with a sealing ring.

[0009] Further, the surface of the metal part of the SMD ceramic packaging shell structure is electroplated with a nickel-gold layer.

[0010] Beneficial effects: the electrode is divided into inner and outer electrode plates, a through hole is processed on the ceramic base, tungsten slurry is printed on the hole wall, silver copper solder is filled in the through hole, and the inner and outer electrode plates are welded on the upper and lower surfaces of the through hole, the solder is adsorbed on the hole wall after melting, the risk of gas leakage after welding the electrode plate is effectively reduced under the condition that the SMD ceramic shell has small size, the requirements of low resistance and high power are realized, and the product qualification rate is improved. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 is the upper surface schematic view of the SMD ceramic base of the utility model;

[0012] Figure 2 is the side cross-sectional schematic view of the SMD ceramic base of the utility model;

[0013] Figure 3 is the lower surface schematic view of the SMD ceramic base of the utility model;

[0014] Figure 4 is the upper surface schematic view of the SMD ceramic packaging shell structure of the utility model;

[0015] Figure 5 is the side cross-sectional schematic view of the SMD ceramic packaging shell structure of the utility model;

[0016] Figure 6 is the lower surface schematic view of the SMD ceramic packaging shell structure of the utility model;

[0017] Figure 7 is the SMD ceramic packaging structure schematic view of the utility model. DETAILED DESCRIPTION

[0018] The utility model will be explained further in combination with the drawings.

[0019] As Figures 1 to 6As shown, an SMD ceramic packaging shell structure includes a ceramic base 1, two inner plates 2, and two outer plates 3. The number of inner plates 2 is consistent with the number of pins of the packaged chip, and the two inner plates 2 are distributed at the two corner positions of one end of the upper surface of the ceramic base 1, and the two outer plates 3 are distributed on the lower surface of the ceramic base 1. The inner plate 2 and the outer plate 3 are arranged opposite to each other. A through hole 4 is provided on the ceramic base 1 at the opposite position of each outer plate 3 and inner plate 2, and a tungsten paste is printed on the hole wall of the through hole 4. The through hole 4 is filled with silver copper solder, and the opposite inner plate 2 and outer plate 3 are welded at the upper and lower ends of the through hole 4, and the silver copper solder is adsorbed on the hole wall of the through hole 4 after melting during plate welding.

[0020] A chip cavity 5 for accommodating a chip is provided on the ceramic base 1, and a heat sink 6 covering the bottom of the chip cavity 5 is welded to the lower surface of the ceramic base 1. A Kovar sealing ring 7 is welded to the upper surface of the ceramic base 1. The surface of the metal part of the SMD ceramic packaging shell structure is electroplated with a nickel-gold layer.

[0021] The process steps for SMD ceramic packaging are as follows:

[0022] a) According to the thickness size of the ceramic base, the corresponding thickness of the film is selected for combination, and then the green ceramic part forming process is performed: punching positioning hole and through hole, through hole wall metallization, printing metal welding pattern, punching chip cavity, then all film laminates are laminated, green ceramic is cut, and then sintering is performed to form mature ceramic parts.

[0023] b) During welding, the ceramic base 1, the sealing ring 7, the inner plate 2 and the outer plate 3 are placed in the mold, and the through hole 4 is filled with silver copper solder for brazing, and finally electroplated to complete the production of the ceramic packaging shell, and obtain the structure as shown in Figure 7 .

[0024] c) The chip 8 is placed in the chip cavity 5, and the lead-out end pad of the chip 8 is connected by bonding wire 9, so that the chip 8 is connected to the external circuit through the outer plate 3 on the lower surface of the ceramic base 1, and then parallel seam welding is performed to weld the cover 10 to the top of the ceramic base 1.

[0025] The number of pins of the SMD device chip is generally small, and the common ones are single pin, two pins or four pins. In this embodiment, the corresponding chip 8 is a two-pin structure.

[0026] The above only describes the preferred embodiments of the present application, and it should be pointed out that for ordinary skilled persons in the technical field, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should be considered as the protection scope of the present application.

Claims

1. An SMD ceramic package housing structure, characterized by, It includes: Ceramic base (1), several inner pole plates (2), outer pole plates (3); the number of inner pole plates (2) is consistent with the pin number of the packaged chip, the inner pole plates (2) are distributed on the upper surface of the ceramic base (1), and the outer pole plates (3) are distributed on the lower surface of the ceramic base (1); the inner pole plates (2) and the outer pole plates (3) are arranged one by one, and a through hole (4) is arranged on the ceramic base (1) at the opposite position, and a tungsten paste is printed on the hole wall of the through hole (4); the through hole (4) is filled with silver copper solder, and the opposite inner pole plate (2) and outer pole plate (3) are welded at the upper and lower ends of the through hole (4), and the silver copper solder is adsorbed on the hole wall of the through hole (4) after melting when the pole plate is welded.

2. The SMD ceramic package housing structure according to claim 1, characterized in that, A core cavity (5) for accommodating a chip is arranged on the ceramic base (1), and a heat sink (6) covering the bottom of the core cavity (5) is welded on the lower surface of the ceramic base (1).

3. The SMD ceramic package housing structure according to claim 1 or 2, characterized in that, The upper surface of the ceramic base (1) is welded with a sealing ring (7).

4. The SMD ceramic package housing structure according to claim 3, characterized in that, The surface of the metal part of the SMD ceramic packaging shell structure is electroplated with a nickel gold layer.

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