A high voltage resistant ceramic insulator structure

Abstract

This invention relates to the field of semiconductor device technology. The invention discloses a high-voltage resistant ceramic insulator structure, including a lead wire, with a ceramic insulator sheathed around the lead wire. The ceramic insulator has a cylindrical structure with a U-shaped cross-section, the U-shaped opening facing outwards from the package housing. A sealing ring is provided between the lead wire and the ceramic insulator, and a frame is fitted around the outer periphery of the ceramic insulator. A base plate is provided at the bottom of the frame, and the base plate and the frame together form a cavity for accommodating semiconductor devices. This invention features high insulation withstand voltage, high current capacity, small size, and high versatility, solving the problems of traditional insulators in simultaneously achieving high insulation withstand voltage, high current capacity, small size, and high versatility. It can be widely used in the packaging housings of various high-reliability devices.

Description

Technical Field

[0001] This invention relates to the field of semiconductor device technology, and in particular to a metal packaging structure with high insulation withstand voltage, high current, high heat dissipation performance, small size, and high versatility. Background Technology

[0002] Discrete semiconductor devices, especially high-power devices, need to withstand high currents and high voltages during operation. Metal packages are the preferred choice for such devices due to their excellent heat dissipation, mechanical properties, and hermeticity.

[0003] In existing technologies, to achieve high-voltage insulation, the common method is to increase the size of the package shell to increase the external creepage distance, such as... Figure 1 As shown, this goes against the trend of miniaturization. Another approach is to add an additional insulating sleeve or silicone wrapping to the outside of the device, which increases process complexity and cost, and may affect heat dissipation efficiency.

[0004] Therefore, there is an urgent need for an innovative metal packaging structure that can fundamentally resolve the contradiction between high pressure resistance and small size. Summary of the Invention

[0005] The purpose of this invention is to provide a high-voltage resistant ceramic insulator structure, which has the characteristics of high insulation withstand voltage, large current, small size and high versatility. It solves the problem that traditional insulators cannot simultaneously achieve high withstand voltage, large current, small size and high versatility, and can be widely used in the packaging shells of various high-reliability devices.

[0006] To solve the above-mentioned technical problems, the present invention provides a high-voltage resistant ceramic insulator structure, including a lead wire, and a ceramic insulator is sleeved on the lead wire; the ceramic insulator has a cylindrical structure with a U-shaped cross-section, and the U-shaped opening faces the outside of the encapsulation shell; a sealing ring is provided between the lead wire and the ceramic insulator, and a frame is sleeved on the outer periphery of the ceramic insulator; a bottom plate is provided at the bottom of the frame, and the bottom plate and the frame together form a cavity for accommodating semiconductor devices.

[0007] The lead wire is made of zirconium copper and extends longitudinally.

[0008] Both the sealing ring and the frame are annular, and the top of the frame is provided with a sealing surface for parallel seam welding.

[0009] The U-shaped structure includes a bottom and two sidewalls extending outward from both sides of the bottom.

[0010] The lead wire passes through the center of the bottom, and the two sidewalls fit against the outer wall of the sealing ring.

[0011] The sealing ring and frame are both made of Kovar alloy 4J29, and the base plate is made of tungsten copper WCu15.

[0012] The cavity is also provided with an insulating and heat-dissipating layer, which is located on the end face of the base plate; the end face of the insulating and heat-dissipating layer is provided with a transition plate, which is connected to the lead wire through a lead post.

[0013] The insulating heat dissipation layer is made of BeO material.

[0014] The transition plate is made of CPC141 material.

[0015] The lead post is made of TU1 material.

[0016] The advantages of this invention compared to the prior art are as follows: 1. Extremely high withstand voltage: The ceramic insulator is designed with a U-shaped structure, which maximizes the creepage distance without increasing the package size, enabling the device to withstand thousands of kilovolts of DC voltage, thus solving the core contradiction between high voltage and miniaturization. 2. Significantly reduced size: Compared with traditional packaging, the packaging volume of this invention can be reduced by 30% to 50% to achieve the same high voltage resistance while maintaining the same large size, which greatly improves power density and saves space; 3. High reliability: It inherits the hermeticity advantage of metal packaging, and the internal chip is fully protected.

[0017] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0018] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0019] Figure 1 This is a schematic diagram of a traditional creepage structure; Figure 2 This is a schematic diagram of the structure of the present invention; Figure 3 This is a dimensional drawing of an embodiment of the present invention; Figure 4 yes Figure 3 The bottom view; Figure 5 yes Figure 3 Side view; Figure 6 yes Figure 5 Cross-sectional view; Figure 7 This is a schematic diagram of the creepage of the present invention.

[0020] In the diagram: 1-lead wire, 2-ceramic insulator, 3-sealing ring, 4-frame, 5-base plate, 6-insulating and heat dissipation layer, 7-transition plate, 8-lead post. Figure 1 In the figure, A is the width of the ceramic insulator extending outwards, which can be adjusted according to the product application; B is the diameter or width of the lead wire. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the embodiments of this invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details are presented in the embodiments of this invention to facilitate a better understanding of this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments. The division of the following embodiments is for ease of description and should not constitute any limitation on the specific implementation of this invention. The embodiments can be combined with and referenced by each other without contradiction.

[0022] Example 1 like Figure 2 As shown, lead 1 is made of zirconium copper to ensure the product's high current carrying capacity and small size. It also possesses excellent bending resistance, remaining unbent under a centrifugal acceleration of 10000g. The ceramic insulator 2 is the insulating part between lead 1 and frame 4. It is made of ceramic, which has advantages such as high hardness, corrosion resistance, good insulation performance, high temperature resistance, light weight, and good thermal conductivity. Its insulation resistance is ≥1× / Ω (DC / 500V), and the ceramic body adopts a U-shaped structure in its shape design. Compared with the traditional structure, this greatly increases the creepage distance and significantly improves the product's withstand voltage capability without changing the volume. Figure 7 As shown; the sealing ring 3 is made of Kovar alloy. The coefficients of thermal expansion of the zirconium copper lead wire and the ceramic differ significantly. To improve the product's resistance to temperature cycling, lead wire 1 and the ceramic are in near-contact. Therefore, to ensure the product's airtightness, a sealing ring is welded externally. Under test condition H1 of method 1071 in GJB128B-2021, the leakage rate is ≤1× / Pa. / s (He); Frame 4 is used for parallel seam welding when sealing the shell. The material is Kovar alloy (4J29). Kovar alloy has the advantages of good thermal stability, easy processing, and corrosion resistance. At the same time, it has good thermal matching with ceramics.

[0023] Example 2 After the design was completed, ceramic insulator 2 adopted 92%... The black ceramic base plate 5 is made of tungsten copper (WCu15), which has good heat dissipation performance and good thermal matching with the frame 4 (4J29). The insulating heat dissipation layer 6 is the insulating part between the core area and the base plate. The material is BeO, which has good heat dissipation performance and a thermal conductivity of 310W / mK. It also has excellent insulation performance. The transition piece 7 is made of CPC141. CPC141 has good thermal matching with the chip and BeO and excellent heat dissipation performance. The lead post 8 is made of TU1 and serves to connect the lead 1 to the core area.

[0024] like Figures 3-6 As shown, dimensions A, C, and R are the length, width, and height of the outer shell, where A = 23.5 mm, C = 23.7 ± 0.4 mm, and R = 9.55 ± 0.2 mm; B and I are the external length and width of the cavity, where B = 12 ± 0.15 mm and I = 16.5 ± 0.15 mm; D is the external extension width of the ceramic insulator, where D = 2.35 ± 0.3 mm; E and F are the internal length and width of the cavity, where E = 14.5 ± 0.15 mm and F = 10 ± 0.15 mm; G and H are the length and width of the BeO, where G = 13.25 ± 0.15 mm and H = 9 ± 0. 15mm; J is the center-to-center spacing of mounting holes on the same side, J=7.1±0.15mm; K is the mounting hole diameter, R=1.1mm; L and M are the center-to-center spacing of the leads, L=4.5mm, M=9mm; N is the distance from the lead to the bottom, N=5.35±0.3mm; P is the base plate thickness, P=1.15mm; Q is the BeO thickness and total CPC thickness, Q=1.6mm; R is the total thickness of the casing, R=9.55±0.2mm; S is the lead diameter, S=1.5±0.1mm; T is the BeO thickness, T=1.3mm.

[0025] The housing is manufactured according to the dimensional drawing. The interior is filled with silicone rubber, and all parts are welded together. Because the selected materials have similar coefficients of thermal expansion, they meet the requirements of GJB923A-2004 General Specification for Semiconductor Discrete Device Housings, with a temperature cycle life of 500 cycles (-55℃~+175℃) and a leakage rate of ≤1× / Pa. The requirements of / s (He) can meet the environmental requirements of aerospace.

[0026] Specifically, the creepage distance has been increased from 3.8mm in the traditional structure to 6.2mm. Based on an air breakdown voltage of 3000V / mm, theoretically, the withstand voltage between the lead and the frame has increased by over 6000V. Furthermore, insulation testing under normal temperature and pressure conditions showed the following withstand voltage between the lead and the frame: the U-shaped structure exhibits an internal lead-frame breakdown. Actual testing demonstrates that the introduction of the U-shaped structure significantly increases its withstand voltage capability.

[0027] In summary, this invention adopts a U-shaped structure design, which achieves high airtightness and small size while ensuring high current and high voltage resistance, which is conducive to product integration and can be widely used in the casing design of high-power products.

[0028] Those skilled in the art will understand that the above embodiments can be modified in form and detail in practical applications without departing from the spirit and scope of the invention.

Claims

1. A high-voltage resistant ceramic insulator structure, characterized in that: Includes a lead wire (1), and a ceramic insulator (2) is provided on the outer sleeve of the lead wire (1); the ceramic insulator (2) has a cylindrical structure with a U-shaped cross-section and the U-shaped opening faces the outside of the encapsulation shell; a sealing ring (3) is provided between the lead wire (1) and the ceramic insulator (2), and a frame (4) is provided on the outer periphery of the ceramic insulator (2); a bottom plate (5) is provided at the bottom of the frame (4), and the bottom plate (5) and the frame (4) together form a cavity for accommodating semiconductor devices.

2. The high-voltage resistant ceramic insulator structure as described in claim 1, characterized in that: The lead (1) is made of zirconium copper material and extends longitudinally.

3. The high-voltage resistant ceramic insulator structure as described in claim 1, characterized in that: Both the sealing ring (3) and the frame (4) are annular, and the top of the frame (4) is provided with a sealing surface for parallel seam welding.

4. The high-voltage resistant ceramic insulator structure as described in claim 1, characterized in that: The U-shaped structure includes a bottom and two sidewalls extending outward from both sides of the bottom.

5. The high-voltage resistant ceramic insulator structure as described in claim 4, characterized in that: The lead wire (1) passes through the center of the bottom, and the two side walls are in contact with the outer wall of the sealing ring (3).

6. The high-voltage resistant ceramic insulator structure as described in claim 1, characterized in that: The sealing ring (3) and the frame (4) are both made of Kovar alloy 4J29, and the base plate (5) is made of tungsten copper WCu15.

7. The high-voltage resistant ceramic insulator structure as described in claim 1, characterized in that: The cavity is also provided with an insulating heat dissipation layer (6), which is located on the end face of the base plate (5); the end face of the insulating heat dissipation layer (6) is provided with a transition piece (7), which is connected to the lead wire (1) through a lead post (8).

8. The high-voltage resistant ceramic insulator structure as described in claim 7, characterized in that: The insulating heat dissipation layer (6) is made of BeO material.

9. The high-voltage resistant ceramic insulator structure as described in claim 7, characterized in that: The transition plate (7) is made of CPC141 material.

10. The high-voltage resistant ceramic insulator structure as described in claim 7, characterized in that: The lead post (8) is made of TU1 material.

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