阅读说明：本技术 一种电子元器件用陶瓷金属封装外壳及陶瓷材料的制备 (Ceramic metal packaging shell for electronic component and preparation of ceramic material ) 是由 袁小意 田晨光 钟永辉 方军 曾辉 史常东 于 2021-09-02 设计创作，主要内容包括：本发明涉及电子元器件气密性封装领域,具体涉及一种电子元器件用陶瓷金属封装外壳及陶瓷材料的制备。包括底板、焊接在底板上的绝缘片和设置在绝缘片四周并焊接在底板上的可伐环框,其特征在于,可伐环框连接引线的一侧设置窗口,窗口内设置陶瓷板,陶瓷板上开设与引线数量相适配的通孔,若干根引线分别穿过通孔进入封装外壳内部；陶瓷板为改性氮化铝陶瓷板。本发明采用陶瓷板的结构代替原有陶瓷珠绝缘子,陶瓷板加工简单,可实现自动化操作。改性的氮化铝陶瓷兼顾了高导热和高热膨胀系数,可提高封装外壳的安全性能。(The invention relates to the field of electronic component air tightness packaging, in particular to a ceramic metal packaging shell for an electronic component and preparation of a ceramic material. The Kovar ring packaging structure comprises a bottom plate, an insulating sheet welded on the bottom plate and a Kovar ring frame arranged around the insulating sheet and welded on the bottom plate, and is characterized in that a window is arranged on one side of the Kovar ring frame, which is connected with leads, a ceramic plate is arranged in the window, through holes matched with the number of the leads are formed in the ceramic plate, and a plurality of leads respectively penetrate through the through holes to enter the packaging shell; the ceramic plate is a modified aluminum nitride ceramic plate. The ceramic plate structure is adopted to replace the original ceramic bead insulator, the ceramic plate is simple to process, and automatic operation can be realized. The modified aluminum nitride ceramic has high heat conductivity and high thermal expansion coefficient, and can improve the safety performance of the packaging shell.)

1. The utility model provides a ceramic metal encapsulates shell for electronic components, includes bottom plate (11), welds insulating piece (12) on bottom plate (11) and sets up kovar ring frame (13) on insulating piece (12) are all around and weld on bottom plate (11), its characterized in that, one side that lead wire (21) are connected to kovar ring frame (11) sets up window (131), set up ceramic plate (30) in window (131), set up through-hole (31) with lead wire (21) quantity looks adaptation on ceramic plate (30), a plurality of lead wires (21) pass respectively through-hole (31) get into encapsulate inside shell (10); the ceramic plate (30) is a modified aluminum nitride ceramic plate.

2. A ceramic metal package for electronic components as claimed in claim 1, wherein said ceramic board (30) is embedded in said window (131), and a joint of said ceramic board (30) and said window (131) is sealed by soldering with pure silver or silver-copper solder.

3. A ceramic metal package casing for electronic component as claimed in claim 1, wherein the surface of the ceramic board (30) is provided with a metalized area, and the inner wall of the through hole (31) is a non-metalized area; the through hole (31) and the lead (21) are sealed by a Kovar transition ring (22).

4. The ceramic metal package casing for electronic components as claimed in claim 1, wherein the insulating sheet (12) is a modified aluminum nitride ceramic insulating sheet.

5. A ceramic metal package shell for an electronic component as claimed in claim 1 or 4, wherein the modified aluminum nitride ceramic comprises aluminum nitride, magnesium oxide and sintering aid in a mass ratio of 1:0.2 (0.03-0.07), and the sintering aid is CaO, Y2O3, CaF₂Any two of the components are mixed according to the mass ratio of 1:1, mixing to obtain the product.

6. A method for preparing the modified aluminum nitride ceramic according to claim 5, comprising the steps of:

s1, weighing aluminum nitride powder according to the mass ratio of 1:0.2 (0.03-0.07): magnesium oxide powder: sintering the auxiliary agent and uniformly mixing;

s2, putting the weighed powder into a ball mill, adding a solvent and a dispersing agent, and carrying out primary ball milling in the ball mill for 16-24 hours; adding an adhesive and a plasticizer for secondary ball milling for 20-26h to obtain slurry;

s3, removing bubbles of the slurry in vacuum, and carrying out tape casting on the slurry after bubble removal by using a tape casting machine to obtain a tape casting blank;

s4, degreasing the casting blank body in inert gas at the degreasing temperature of 400-500 ℃;

s5, placing the degreased casting blank into a sintering furnace, and keeping the temperature of 1500-1600 ℃ for 2-6h in a nitrogen atmosphere.

7. The method for preparing the modified aluminum nitride ceramic according to claim 6, wherein the aluminum nitride powder has an oxygen content of 0.5 to 1.5 wt% and a D50 value of 0.5 to 2 μm; the magnesium oxide powder D50 is 0.5-2 μm.

8. The method for preparing the modified aluminum nitride ceramic according to claim 6, wherein the solvent is prepared by mixing ethanol, isopropanol and butanone according to a mass ratio of 1:1:2, and the dispersant is one or more of oleic acid, glycerol trioleate, fish oil and acrylic resin.

9. The method of preparing a modified aluminum nitride ceramic according to claim 6, wherein the plasticizer is dimethyl phthalate (DMP) and/or Butyl Benzyl Phthalate (BBP); the adhesive is polypropylene carbonate resin.

10. The method for preparing a modified aluminum nitride ceramic according to any one of claims 6 to 9, wherein the mass ratio of the aluminum nitride powder, the magnesium oxide powder, the sintering aid, the dispersant, the binder, the plasticizer and the solvent is 1:0.2 (0.03-0.07): 0.01-0.03): 0.05-0.30): 0.03-0.05): 0.70-0.90.

Technical Field

The invention relates to the field of electronic component packaging, in particular to a ceramic metal packaging shell for an electronic component and preparation of a ceramic material.

Background

With the requirements of integration, miniaturization and high reliability of electronic components, a bare chip is often adopted for airtight packaging, and high voltage, large current and high heat dissipation capacity are taken into consideration. The conventional industrial grade product is packaged by plastic package, the product grade is low, the watertight requirement can only be met, and the airtight and high-reliability packaging shell is gradually packaged by glass or ceramic. For a high-current copper lead shell, only a ceramic packaging mode can be adopted, at present, aluminum oxide ceramic beads are often adopted for internal and external metallization to weld leads, the heat conducting capacity of the ceramic beads is low, and the packaging enables the product to have the problems of poor air tightness consistency, high product price, poor heat conduction and the like and low reliability. Moreover, the insulating sheet arranged in the ceramic package generally adopts a beryllium oxide insulating sheet, but beryllium oxide powder is toxic, and poisoning risks can be brought in the production and use processes.

Disclosure of Invention

In order to solve the problems in the prior art, an object of the present invention is to provide a ceramic metal package casing for an electronic component.

The technical scheme adopted by the invention is as follows: a ceramic metal packaging shell for electronic components comprises a bottom plate, an insulating sheet welded on the bottom plate and a Kovar ring frame arranged around the insulating sheet and welded on the bottom plate, wherein an open window is arranged on one side of a connecting lead of the Kovar ring frame, a ceramic plate is arranged in the window, through holes matched with the number of the leads are formed in the ceramic plate, and a plurality of leads respectively penetrate through the through holes to enter the packaging shell; the ceramic plate is a modified aluminum nitride ceramic plate.

Preferably, the ceramic plate is embedded in the window, and the joint of the ceramic plate and the window is sealed by pure silver or silver-copper solder brazing.

Preferably, a metalized area is arranged on the surface of the ceramic plate, and the inner wall of the through hole is a non-metalized area; a Kovar transition ring is used for sealing between the through hole and the lead wire; the kovar transition ring is arranged on the outer surface side of the ceramic plate.

Preferably, the insulating sheet is a modified aluminum nitride ceramic insulating sheet.

Preferably, the modified aluminum nitride ceramic comprises aluminum nitride, magnesium oxide and a sintering aid in a mass ratio of 1:0.2 (0.03-0.07), wherein the sintering aid is CaO, Y2O3 and CaF₂Any two of the components are mixed according to the mass ratio of 1:1 are mixed to obtain the product.

The second purpose of the invention is to provide a preparation method of the modified aluminum nitride ceramic used for the ceramic packaging shell, which comprises the following steps:

s1, weighing aluminum nitride powder according to the mass ratio of 1:0.2 (0.03-0.07): magnesium oxide powder: sintering the auxiliary agent and uniformly mixing;

s2, putting the weighed powder into a ball mill, adding a solvent and a dispersing agent, and carrying out primary ball milling in the ball mill for 16-24 hours; adding an adhesive and a plasticizer for secondary ball milling for 20-26h to obtain slurry;

s3, removing bubbles of the slurry in vacuum, and carrying out tape casting on the slurry after bubble removal by using a tape casting machine to obtain a tape casting blank;

s4, degreasing the casting blank body in inert gas at the degreasing temperature of 400-500 ℃;

s5, placing the degreased casting blank into a sintering furnace, and keeping the temperature of 1500-1600 ℃ for 2-6h in a nitrogen atmosphere.

Preferably, the oxygen content of the aluminum nitride powder is 0.5-1.5 wt%, and the D50 is 0.5-2 μm; the magnesium oxide powder D50 is 0.5-2 μm.

Preferably, the solvent is prepared by mixing ethanol, isopropanol and butanone according to the mass ratio of 1:1:2, and the dispersing agent is one or more of oleic acid, glycerol trioleate, fish oil and acrylic resin.

Preferably, the plasticizer is dimethyl phthalate DMP and/or butyl benzyl phthalate BBP; the adhesive is polypropylene carbonate resin.

Preferably, the mass ratio of the aluminum nitride powder to the magnesium oxide powder to the sintering aid to the dispersant to the binder to the plasticizer to the solvent is 1:0.2 (0.03-0.07) to 0.01-0.03 (0.05-0.30) to 0.03-0.05 to 0.70-0.90.

The invention has the beneficial effects that:

1) in the prior art, a lead wire penetrates through a packaged kovar ring frame and is sealed by a ceramic bead insulator, a ceramic bead structure needs to be pressed and sintered independently, manual operation or semi-automatic operation can be only adopted for internal and external partial metallization or internal full metallization of the ceramic bead, the overall alignment precision is poor, and the product quality is uncontrolled due to human factors. The ceramic plate is creatively adopted to replace the original ceramic bead insulator, the ceramic plate is simple to process, the metallization only needs to be carried out on two opposite surfaces of the ceramic plate, no metallization is arranged in the through hole, and automatic operation can be realized.

2) The ceramic plate structure replaces independent ceramic beads, and the problems of air tightness and the like caused by inconsistent metallization and the like are solved. The ceramic plate has high surface metallization automation degree, good quality consistency and greatly improved yield, the ceramic cost is about 1/15 of the original imported ceramic beads, the total product cost is about 55 percent of the total product cost of the used ceramic beads, and the ceramic plate is favorable for market popularization of products.

3) The high-power product leads to the length and adopts kovar copper-clad lead wire, and the oxygen-free copper lead wire brings the promotion of lead wire electric current, causes thermal a large amount of accumulations, and the heat can not in time give off the security that will reduce the product. Although the common alumina ceramics has good heat matching with Kovar high-temperature welding, the heat conduction is poor; the aluminum nitride ceramics have high heat conduction but small thermal expansion coefficient, and both are not suitable for serving as insulators of high-power devices to meet the use requirements of the insulators. The ceramic plate uses the modified aluminum nitride ceramic, a certain amount of alkaline earth metal oxide and the like are added into the aluminum nitride ceramic powder to form a glass phase so as to improve the thermal expansion coefficient of the material, the modification of the aluminum nitride ceramic material takes high thermal conductivity and high thermal expansion coefficient into consideration, the high-temperature thermal adaptation with kovar materials can be realized, and the ceramic plate has a larger area and can realize rapid heat dissipation.

4) The modified aluminum nitride ceramic prepared by the invention has the advantages that the glass phase is formed by low-cost aluminum nitride powder and alkaline earth metal, the sintering temperature is reduced by doping sintering aids, the high-temperature sintering temperature above 1800 ℃ can be reduced to below 1600 ℃, and the production cost is reduced. At the same time, the thermal expansion coefficient is increased to 5.8-6.2 x 10^-6The thermal conductivity is obviously improved to be more than 130 w.m/K compared with 15 w.m/K of the alumina ceramic, and meanwhile, the preparation method of the modified aluminum nitride ceramic can reduce the sintering temperature.

5) The ceramic plate insulator is of a square structure, is favorable for positioning the flat head lead, prevents inclination, is particularly favorable for being welded on the ring frame, and can avoid scrapping of the whole product due to poor positioning of the flat head of the lead.

6) The original insulating sheet is made of beryllium oxide ceramic, but beryllium oxide powder is toxic, and occupational health hazards may be caused in the production process. The invention adopts the aluminum nitride ceramic with high thermal conductivity to replace the beryllium oxide insulating sheet, has no toxicity and pollution, and can realize green production and application. The aluminum nitride ceramic thermal conductivity 170-270 w.m/k is equivalent to that of beryllium oxide 150-300 w.m/k, and meanwhile, the thermal expansion coefficient is small, so that the aluminum nitride ceramic is equivalent to a welded bottom plate such as a molybdenum sheet, the thermal stress is small, and the replacement can be completely realized and the product performance can be improved. And when the ceramic insulation sheet is welded on the bottom plate, the whole process can not be cracked and further generate powder toxicity due to collision and the like.

Drawings

FIG. 1 is a schematic structural diagram of a package housing according to the present invention;

FIG. 2 is a top view of FIG. 1;

FIG. 3 is a right side view of FIG. 2;

FIG. 4 is a schematic diagram of a ceramic plate structure according to the present invention, wherein the metallization regions are shaded;

FIG. 5 is a schematic view showing the connection of a ceramic board to a lead wire according to the present invention;

fig. 6 is a left side view of fig. 5.

The notations in the figures have the following meanings:

10-packaging shell 11-bottom plate 111-positioning hole 12-insulating sheet 121-transition sheet

13-ring frame 131-window

21-lead 22-covar transition ring

30-ceramic plate 31-through hole

Detailed Description

The technical solution of the present invention is described below with reference to the accompanying drawings for facilitating understanding of those skilled in the art.

Example 1

As shown in fig. 1 to 3, a ceramic metal package casing 10 for an electronic component includes a base plate 11, an insulating sheet 12 welded to the base plate 11, and a kovar ring frame 13 made of kovar alloy and disposed around the insulating sheet 12 and welded to the base plate 11. The base plate 11 is made of tungsten or molybdenum base material, the insulating sheet 12 is provided with a transition sheet 121, and the base plate 11 is further provided with a positioning hole 111.

An open window 131 is arranged at one side of the Kovar ring frame 13, which is connected with the lead 21, a ceramic plate 30 matched with the window 131 in size is embedded in the window 131, and the joint of the ceramic plate 30 and the window 131 is sealed by pure silver or silver-copper solder in a soldering mode.

The thickness of the ceramic plate 30 may be smaller than or equal to the thickness of the kovar ring frame 13, and in this embodiment, the thickness of the ceramic plate 30 is smaller than the thickness of the kovar ring frame 13, which facilitates the positioning and installation of the ceramic plate 30 on the kovar ring frame 13.

The ceramic board 30 is provided with through holes 31 having the same number as that of the leads 21, the surface of the ceramic board 30 is provided with metalized areas, and the inner walls of the through holes 31 are non-metalized areas. In this embodiment, three leads 21 respectively pass through three through holes 31 and enter the package housing 10, the through holes 31 and the leads 21 are sealed by kovar transition rings 22, and the kovar transition rings 22 are sleeved on the leads and attached to the outer surface of the ceramic board 30 for sealing. In other embodiments, the number of the leads 21 may be one or more according to the electronic component.

The ceramic plate 30 is a modified aluminum nitride ceramic plate. In this embodiment, the insulating sheet 13 is a modified aluminum nitride ceramic plate made of the same material as the ceramic plate.

The modified aluminum nitride ceramic comprises aluminum nitride, magnesium oxide and sintering aid in a mass ratio of 1:0.2 (0.03-0.07), wherein the sintering aid is CaO and Y₂O₃、CaF₂Any two of the components are mixed according to the mass ratio of 1:1 and mixing.

Example 2

The method for preparing the modified aluminum nitride ceramic of example 1 includes the following steps:

s1, weighing aluminum nitride powder, magnesium oxide powder and sintering aid according to the mass ratio of 1:0.2 (0.03-0.07), and uniformly mixing. Wherein the oxygen content of the aluminum nitride powder is 0.5-1.5 wt%, and the D50 is 0.5-2 μm; the magnesium oxide powder D50 is 0.5-2 μm; the sintering aid is CaO and Y₂O₃、CaF₂Any two of the components are mixed according to the mass ratio of 1:1 and mixing.

S2, putting the weighed powder into a ball mill, adding a solvent and a dispersing agent, and carrying out primary ball milling in the ball mill for 16-24 hours; adding an adhesive and a plasticizer for secondary ball milling for 20-26h to obtain slurry;

wherein the solvent is prepared by mixing ethanol, isopropanol and butanone according to the mass ratio of 1:1: 2; the dispersant is one or more of oleic acid, triolein, fish oil and acrylic resin; the plasticizer is dimethyl phthalate DMP and/or butyl benzyl phthalate BBP; the adhesive is polypropylene carbonate resin.

S3, removing bubbles of the slurry in vacuum, and carrying out tape casting on the slurry after bubble removal by using a tape casting machine to obtain a tape casting blank;

s4, degreasing the casting blank body in inert gas at the degreasing temperature of 400-500 ℃;

s5, placing the degreased casting blank into a sintering furnace, and preserving heat for 2-6h at 1500-1600 ℃ in a nitrogen atmosphere to obtain the required modified aluminum nitride ceramic.

In the method, the mass ratio of the aluminum nitride powder to the magnesium oxide powder to the sintering aid to the dispersant to the adhesive to the plasticizer to the solvent is 1:0.2 (0.03-0.07) to 0.01-0.03 (0.05-0.30) to 0.03-0.05 to 0.70-0.90.

The prepared modified aluminum nitride ceramic is processed to obtain a ceramic plate 30 with a through hole 31, and the process of packaging the electronic component by using the ceramic plate 30 is as follows: the insulating plate 12 is first brazed to the base plate 11, and the kovar ring frame 13 is then disposed around the insulating plate 12 and brazed to the base plate 11. The ceramic plate 30 with the through-hole 31 formed therein is connected to the lead 21 to form an insulator assembly, and the ceramic plate 30 is welded to the kovar ring frame 13 in the window 131.

In the present invention, the ceramic plate 30 can be obtained by automatic laser drilling, screen printing, metal sintering and electroplating after the whole ceramic material is set by a machining program, and finally, automatic scribing and cutting by laser or a grinding wheel.

Example 3

With the ceramic metal packaging shell prepared by the application and the existing product for test comparison, three groups of test groups respectively use the modified aluminum nitride provided by the application, the main components of the modified aluminum nitride in the three groups are the same, and the sintering aid is Y in the modified aluminum nitride A₂O₃And CaF₂(ii) a The sintering aid in the modified aluminum nitride B is Y₂O₃And CaO; the sintering aid in the modified aluminum nitride C is CaO and CaF₂(ii) a Comparative examples two groups used commercially available high purity aluminum nitride and high purity alumina ceramics, respectively. The results of the property comparison are shown in Table 1 below

TABLE 1 comparison of the Properties of different Package housings

As can be seen from Table 1, the coefficient of thermal expansion of the modified aluminum nitride ceramic prepared by the invention can reach 5.8-6.2 x 10^-6The thermal conductivity of the alumina ceramic is obviously improved, and the thermal conductivity is improved to 130 w.m/K or more from 15 w.m/K of the alumina ceramic. In the embodiment, the product airtightness is tested by using a temperature cycle method, and the temperature cycle test is implemented by referring to a temperature cycle standard flow under the condition F (100 times, -65 ℃ -175 ℃) in a method 1010.1 in GJB 548B-2005 national military industry Standard microelectronic device test method and program. The results show that the test group has better air tightness than the high-purity aluminum nitride used in comparative example 1, and the test group and the comparative example2, the used high-purity alumina is equivalent, which shows that the invention can not only ensure the use safety, but also meet the air tightness requirement.

The above is only a preferred embodiment of the invention, and is not intended to limit the invention; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that: any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.