CN113896540A

CN113896540A - Preparation method of aluminum nitride ceramic structural member

Info

Publication number: CN113896540A
Application number: CN202111250167.XA
Authority: CN
Inventors: 郭军; 党军杰; 张�浩; 许海仙; 张志成; 刘小东; 曾辉; 史常东; 崔嵩
Original assignee: Hefei Shengda Electronic Technology Industrial Co ltd; CETC 43 Research Institute
Current assignee: Hefei Shengda Electronic Technology Industrial Co ltd; CETC 43 Research Institute
Priority date: 2021-10-26
Filing date: 2021-10-26
Publication date: 2022-01-07
Anticipated expiration: 2041-10-26
Also published as: CN113896540B

Abstract

The invention discloses a preparation method of an aluminum nitride ceramic structural member, belonging to the field of preparation methods of structural members, comprising the following steps: step 1: preparing AlN ceramic substrates required by the assembly units; step 2: processing each ceramic substrate into an assembly unit meeting the precision requirement; and step 3: selecting a component unit and printing silver-copper-titanium active slurry; and 4, step 4: assembling and welding each assembly unit into a structural member; and 5: and (5) cleaning and checking the structural member. The method divides the structural part into a plurality of small unit parts, prints the silver-copper-titanium active slurry on the unit parts, and assembles the unit parts into the structural part through a welding process, does not need CNC (computer numerical control) processing, has easy control of single precision, good consistency, high finished product rate and low cost, and meets the requirements of long-term use within the range of-55-400 ℃, and the like.

Description

Preparation method of aluminum nitride ceramic structural member

Technical Field

The invention relates to the field of a preparation method of a structural member, in particular to a preparation method of an aluminum nitride ceramic structural member.

Background

Along with the increasing multifunctionalization and automation degree of equipment in the industries of electronic information, power electronics, semiconductor laser and the like, the requirements on the service life, the wear resistance and the reliability of equipment are increased, and more ceramic structural members are gradually used, particularly the requirements on the stability and the heat conductivity of materials are higher. The traditional ceramic materials mainly comprise aluminum oxide (Al2O3), zirconium oxide (ZrO2) and beryllium oxide (BeO), wherein the Al2O3 and ZrO2 materials have the advantages of low thermal conductivity (below 30W/m.K), BeO is gradually eliminated due to powder poison generated in the processing process, and AlN has the advantages of high thermal conductivity of 160-230W/m.K, low dielectric constant, no poison, good thermal stability and the like, so that the traditional ceramic materials gradually show great superiority in the fields of high-power module circuits, semiconductor equipment, optoelectronic modules and the like, and have wide market prospects.

The common preparation methods of AlN structural members comprise a CNC (computerized numerical control) machining method, injection molding and the like, and at present, ceramic structural members basically adopt a CNC and an injection molding method, wherein the CNC and the injection molding method need to finely process high-precision products, and the CNC can produce the ceramic structural members with excellent performance and beautiful appearance. However, the method for machining the whole thick ceramic plate by the CNC machine has long time, low material utilization rate and high cost; the injection molding method has high technical requirements on slurry preparation, high glue discharging and sintering process shrinkage deformation control consistency, and the sintered blank can meet the precision requirement only through CNC (computerized numerical control) processing.

Disclosure of Invention

The present invention is directed to a method for manufacturing an aluminum nitride ceramic structural member, so as to solve the problems in the background art.

In order to achieve the purpose, the invention provides the following technical scheme:

a preparation method of an aluminum nitride ceramic structural member comprises the following steps:

step 1: preparing AlN ceramic substrates required by the assembly units;

step 2: processing each ceramic substrate into an assembly unit meeting the precision requirement;

and step 3: selecting a component unit and printing silver-copper-titanium active slurry;

and 4, step 4: assembling and welding each assembly unit into a structural member;

and 5: and (5) cleaning and checking the structural member.

As an improvement scheme of the invention, in the step 2, the planeness of the processed assembly unit is less than or equal to 0.02mm, and the roughness Ra is less than 0.5 mu m.

As an improvement scheme of the invention, in the step 3, the step of selecting the component unit to print the silver-copper-titanium active paste specifically comprises the following steps:

step 3.1: ultrasonically cleaning the selected component units by cleaning fluid and alcohol, drying and printing;

step 3.2: uniformly stirring the silver-copper-titanium active slurry and spreading the silver-copper-titanium active slurry on a printing screen; adjusting the pressure of the frictioning and the mesh spacing speed, and controlling the thickness of the wet film within the range of 30-100 mu m;

step 3.3: putting the printed assembly unit in the step 3.2 into an oven filled with protective gas, and drying for 30-60 min at 120 ℃;

step 3.4: testing the thickness of the dry film, and controlling the thickness to be within the range of 20-90 μm.

As an improvement of the present invention, the assembling and welding of the assembly units into the structural member in step 4 specifically includes:

step 4.1: assembling the assembly units obtained in the

steps

2 and 3, and fixing by adopting a clamp or a heavy object during assembly;

step 4.2: after being assembled, all the assembly units are put into a vacuum welding furnace for vacuum welding, the welding temperature is 750-850 ℃, and the vacuum degree is 8 x 10^-4～15*10^-4And (4) keeping the temperature within the range of Pa for 10-80 min, and naturally cooling to 80 ℃ after the temperature is kept, and discharging.

In step 5, the cleaning mode of the structural part is one or more of acid washing, water washing and alcohol cleaning.

As a modified version of the present invention, in step 1, the preparation of the ceramic substrate includes the following steps:

step 1.1: preparing granulation slurry according to the following mixture ratio: the AlN powder comprises the following components in percentage by weight: 55-58%; the weight percentage of the sintering aid is as follows: 3 percent; the weight percentage of the dispersant is as follows: 0.5 percent; the weight percentage of the binder is as follows: 7-15%; the weight percentage of the solvent is as follows: 26-32%;

step 1.2: and (4) dry-pressing the granulation slurry into a green blank according to the size requirement of each assembly unit, and then discharging glue and sintering to obtain the AlN substrate.

As an improvement scheme of the invention, the AlN powder has the average particle size of 0.5-1.8 mu m, the specific surface area of 2-3.4 square meters per gram and the oxygen content of less than 0.9 percent.

Has the advantages that: the structural member is divided into a plurality of small unit parts, silver, copper and titanium active slurry is printed on the unit parts, and then the ceramic substrate and the ceramic substrate are directly welded through a welding process, so that the structural member is assembled and can be used for a long time within the range of-55-400 ℃. According to the invention, CNC machining is not needed, the cost is effectively reduced, direct welding can be performed between ceramics, high-temperature sintering of tungsten paste on the surface of the ceramic substrate is not needed, nickel electroplating is performed again, and silver-copper welding is used, which is the same as that of the traditional ceramic welding method, so that the process steps are saved, the efficiency is improved, and the adhesive force (more than 14N/mm) of silver-copper-titanium welding is far higher than that of silver-copper welding (6-8N/mm). In addition, due to the adoption of a unit processing method, the flatness control of the structural part can be effectively improved, and the method has the characteristics of easiness in single precision control, good consistency, high yield and the like.

Drawings

FIG. 1 is a schematic process flow diagram of the present invention;

FIG. 2 is a schematic view of the component units and an aluminum nitride structure according to example 1 of the present invention;

FIG. 3 is a schematic view of the component units and an aluminum nitride structure according to example 2 of the present invention;

FIG. 4 is a schematic structural diagram of each component unit according to embodiment 3 of the present invention;

fig. 5 is a schematic structural diagram of each assembly unit of embodiment 3 of the present invention when assembled.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, the method for preparing an aluminum nitride ceramic structural member provided by the invention adopts a multi-component unit mode, prepares each component unit into a required structure, prints active slurry on the component units, and finally assembles the structural member in an integral welding mode. The method does not need CNC integral processing and injection molding, and has the characteristics of easy control precision, good consistency and high yield. The following examples are intended to illustrate the details.

Example 1, as shown in fig. 2, the structure was a single-layer step structure with dimensions of 60mm by 50mm by 12mm (length by width by height) and a step height of 4 mm. In the embodiment, the aluminum nitride structural member is divided into 2 component units, wherein the first component unit 1 corresponds to an AlN substrate I with the size of 60mm x 50mm x 8 mm; the second module cell 2 corresponds to a second AlN substrate of 50mm by 40mm by 4mm in size. The preparation steps of the structural member are as follows:

step 1: preparing a first AlN substrate and a second AlN substrate, specifically, comprising the following steps:

step 1.1: adopting self-made AlN powder, the average particle size of the powder is 1.5 mu m, the specific surface area BET is 3.2 square meters per gram, the oxygen content is less than 0.9 percent, and Y is₂O₃The particle size of the powder is in the range of 0.8-3.0 μm. Preparing the granulating slurry from AlN powder, a sintering aid, a dispersing agent, a binder and a solvent according to the following mixture ratio:

57 percent of AlN powder;

the weight percentage of the sintering aid is 3 percent;

the weight percentage of the dispersant is 0.5 percent;

the weight percentage of the binder is 7.5 percent;

the weight percentage of the solvent is 32 percent;

the sintering aid is one or two of rare earth metal oxides Y2O3 and Sm2O3, the dispersant is one or two of oleic acid, triolein, fish oil and the like, the binder is polyvinyl butyral (PVB), and the solvent is a multi-component mixed system of ethanol, acetone and butanone.

Step 1.2: and dry pressing the granulated powder into green bodies with the specifications of 80mm × 70mm × 10mm and 70mm × 60mm × 5.5mm, and then carrying out gel discharge at 500 ℃ for 60h and sintering at 1820 ℃ for 6h to prepare the AlN substrate I with the specification of 67mm × 58mm × 8.4mm (length × 58mm × width × height) and the AlN substrate II with the specification of 58mm × 50mm × 4.5mm (length × width × height).

Step 2: (1) processing the AlN substrate I to obtain a first assembly unit 1:

1) post-processing-double side lapping

Carrying out double-sided grinding on a 67mm 58mm 8.4mm AlN substrate I, controlling the thickness of the AlN substrate I within 8.00 +/-0.02 mm, controlling the flatness within 0.01mm and controlling the roughness to be Ra less than 0.5 mu m;

2) post-machining-abrasive cutting

Cutting the grinded AlN substrate I on a grinding wheel cutting machine, wherein a diamond blade can be selected, and the scribing speed is controlled to be 1 mm/s; cutting the long edge to 60.00 +/-0.03 mm; the width is controlled to be 50.00 +/-0.03 mm.

(2) Processing the AlN substrate II to obtain a second assembly unit 2:

1) post-processing-double side lapping

Carrying out double-sided grinding on the AlN substrate II, controlling the thickness of the AlN substrate II within 4.00 +/-0.02 mm, controlling the flatness within 0.01mm, and controlling the roughness Ra to be less than 0.5 mu m;

2) post-machining-abrasive cutting

Cutting the grinded AlN substrate II on a grinding wheel cutting machine, wherein a diamond blade can be selected, and the scribing speed is controlled to be 1 mm/s; cutting the long edge to 50.00 +/-0.03 mm; the width is controlled to be 40.00 +/-0.03 mm.

And step 3: printing silver, copper and titanium active slurry on the second assembly unit 2; the method specifically comprises the following steps:

step 3.1: ultrasonically cleaning the second assembly unit 2 by cleaning solution and alcohol respectively, drying and printing;

step 3.2: uniformly stirring the silver-copper-titanium active slurry and spreading the silver-copper-titanium active slurry on a printing screen; adjusting the frictioning pressure to be 0.3MPa and the mesh spacing speed to be 400mm/s, and controlling the thickness of the wet film to be 40-60 mu m;

step 3.3: drying the printed second assembly unit 2 in an oven filled with protective gas at 120 ℃ for 30-60 min;

step 3.4: testing the thickness of the dry film, and controlling the thickness to be within the range of 30-50 μm.

And 4, step 4: assembling and welding each assembly unit into a structural member; the method specifically comprises the following steps:

step 4.1: assembling the printed second assembly unit 2 and the first assembly unit 1, and tightly pressing the top ends of the second assembly unit and the first assembly unit by using a heavy tungsten block;

step 4.2: putting the assembled die into a vacuum welding furnace, vacuumizing and welding, and controlling the vacuum degree to be 8 x 10^-4Keeping the temperature within the range of Pa and at the temperature of 750-820 ℃ for 40min, then naturally cooling, and discharging when the temperature is reduced to 80 ℃;

and 5: and (3) disassembling the tool, putting the structural part obtained in the step (4) into acid degreasing liquid for cleaning for 5min, ultrasonically cleaning in pure water for 3min, then ultrasonically cleaning with alcohol for 2min, drying in an oven for 10min, and then inspecting the surface and the size.

Example 2, as shown in FIG. 3, the structural member was a crucible structure having an outer dimension of

The thickness of the bottom plate and the wall is 2 mm. In the embodiment, the structural member is divided into 2 component units, wherein the first component unit 1 has the corresponding size of

The AlN disk substrate; the second assembly unit 2 corresponds to a size of

The thickness is 2mm AlN round barrel. The preparation steps of the structural member are as follows:

step 1: the preparation method of the AlN disc substrate and the AlN barrel comprises the following steps:

56 percent of AlN powder;

the weight percentage of the sintering aid is 3 percent;

the weight percentage of the dispersant is 0.5 percent;

the weight percentage of the binder is 12 percent;

the weight percentage of the solvent was 28.5%.

The sintering aid is one or two of rare earth metal oxides Y2O3 and Sm2O3, the binder is polyvinyl butyral (PVB), and the solvent is a multi-component mixed system of ethanol, acetone and butanone.

Step 1.2: dry pressing the powder to granulate

Green bodies with two specifications of (bottom surface diameter x height) 2.4mm and 132mm x 2.8mm (length x width x height) are subjected to binder removal at 500 ℃ for 36h and sintered at 1820 ℃ for 4h to obtain the ceramic material

AlN cylinders with a thickness of 2mm and AlN disc substrates of 110mm by 2.3mm (length by width by height).

Step 2: (1) fixing an AlN barrel on a single-side grinding machine, respectively grinding two ends of the AlN barrel, controlling the height to be 78mm +/-0.05 mm, controlling the flatness to be within 0.01mm, and controlling the roughness Ra to be less than 0.5 mu m to obtain a first assembly unit 1:

(2) the AlN disk substrate was double-side polished to control the thickness to 2.00. + -. 0.02mm, the flatness to 0.01mm and the roughness Ra to less than 0.5. mu.m, to obtain a second module unit 2.

step 3.2: uniformly stirring the silver-copper-titanium active slurry and spreading the silver-copper-titanium active slurry on a printing screen; adjusting the frictioning pressure to be 0.3MPa, the mesh spacing speed to be 300mm/s, and controlling the thickness of the wet film to be 60-100 mu m;

step 3.3: after printing, the second assembly unit 2 is placed into an oven filled with protective gas to be dried for 30-60 min at 120 ℃;

step 3.4: testing the thickness of the dry film, and controlling the thickness to be within the range of 50-90 μm.

step 4.2: putting the assembled die into vacuum weldingVacuum welding in furnace with vacuum degree controlled at 8 × 10^-4Controlling the temperature within the range of Pa to be 750-850 ℃, preserving the heat for 10min, then naturally cooling, and discharging when the temperature is reduced to 80 ℃;

Example 3, as shown in fig. 4, the structural member was a cavity structure with an outer dimension of 110mm x 84mm x 20mm (length x width x height) and a base plate thickness of 4 mm. In this embodiment, the structural members are divided into 5 component units, wherein the first component unit 1 corresponds to a first AlN substrate having a size of 106mm × 80mm × 4mm (length × width × height), the second component unit 2 corresponds to a second AlN substrate having a size of 106mm × 20mm × 2mm (length × width × height), the third component unit 3 corresponds to a third AlN substrate having a size of 106mm × 20mm × 2mm (length × width × height), and the fourth component unit 4 and the fifth component unit 5 correspond to fourth AlN substrates and fifth AlN substrates having a size of 84mm × 20mm × 2mm (length × width × height), respectively. The preparation steps of the structural member are as follows:

step 1.1: adopting self-made AlN powder, the average particle size of the powder is 1.5 mu m, the specific surface area BET is 3.2 square meters per gram, the oxygen content is less than 0.9 percent, and Y is₂O₃The particle size of the powder is in the range of 0.6-2.4 μm. Preparing the granulating slurry from AlN powder, a sintering aid, a dispersing agent, a binder and a solvent according to the following mixture ratio:

56 percent of AlN powder;

the weight percentage of the sintering aid is 3 percent;

the weight percentage of the dispersant is 0.5 percent;

the weight percentage of the binder is 8.5 percent;

the weight percentage of the solvent is 32 percent;

Step 1.2: because the width sizes of the second, third, fourth and

fifth component units

2, 3, 4 and 5 are similar, only two specifications of green blanks of 132mm 100mm 5.6mm and 132mm 2.8mm are needed to be prepared, and the green blanks are subjected to glue removal at 500 ℃ for 48h and sintering at 1820 ℃ for 6h to prepare an AlN substrate of 110mm 84mm 4.2mm specification and an AlN master plate of 110mm 2.3 mm.

Step 2: (1) processing the AlN substrate I to obtain a first assembly unit 1:

1) post-processing-double side lapping

Double-sided grinding is carried out on a first AlN substrate of 110mm 84mm 4.2mm, the thickness of the first AlN substrate is controlled to be 4.00 +/-0.02 mm, the flatness is controlled to be within the range of 0.01mm, and the roughness Ra is smaller than 0.5 mu m;

2) post-machining-abrasive cutting

Cutting the grinded AlN substrate I on a grinding wheel cutting machine, wherein a diamond blade can be selected, and the scribing speed is controlled to be 1.5 mm/s; cutting the long edge to 106.00 +/-0.02 mm; the width is controlled to be 80.00 +/-0.02 mm.

(2) Processing the AlN master plate to obtain a second assembly unit 2:

1) post-processing-double side lapping

Carrying out double-sided grinding on an AlN master plate of 110mm 2.3mm, controlling the thickness to be 2.00 +/-0.02 mm and the flatness to be within 0.01mm, and controlling the roughness Ra to be less than 0.5 mu m.

2) Post-machining-abrasive cutting

Opening and cutting the ground AlN master plate on a grinding wheel cutting machine, wherein a fiber laser can be selected, and the cutting speed is controlled to be 2 mm/s; controlling the scribing size of the outline edge to be 30 mm/s; and (4) pickling the cut substrate for 2-4h, and removing cutting residues.

3) Post-machining-abrasive cutting

Marking a grinding wheel cutting line along the scribing line after laser cutting, and cutting an AlN substrate II from the AlN master plate on a grinding wheel cutting machine, wherein a diamond blade can be selected, and the scribing speed is controlled at 3 mm/s; cutting the long edge to 106.00 +/-0.02 mm; the width is controlled to be 20.00 +/-0.02 mm.

(3) Processing the AlN master plate to obtain a third assembly unit 3:

1) post-processing-double-side lapping (if this step is already carried out when preparing the second module unit 2, this step can be omitted, the same applies below)

2) Post-machining-abrasive cutting

Opening and cutting the ground AlN master plate on a grinding wheel cutting machine, wherein a diamond blade can be selected, and the scribing speed is controlled to be 3 mm/s; cutting the long edge to 106.00 +/-0.02 mm; the width is controlled to be 20.00 +/-0.02 mm.

(4) Processing the AlN master plate to obtain a fourth assembly unit 4 and a fifth assembly unit 5:

1) post-processing-double side lapping

Carrying out double-sided grinding on a substrate of which the mother set is 110mm by 2.3mm, controlling the thickness of the substrate within 2.00 +/-0.02 mm, controlling the flatness within 0.01mm and controlling the roughness Ra to be less than 0.5 mu m;

2) post-machining-laser cutting

Opening a hole on the ground substrate on a laser machine for cutting, wherein a fiber laser is selected, the cutting speed is controlled to be 2mm/s, and the outline edge scribing size is controlled to be 30 mm/s; pickling the cut substrate for 2-4h, and removing cutting residues;

3) post-machining-abrasive cutting

Marking a grinding wheel cutting line along the scribing line after laser cutting, cutting an AlN mother plate into an AlN substrate four and an AlN substrate five on a grinding wheel cutting machine, wherein a diamond blade is selected, and the scribing speed is controlled to be 3 mm/s; cutting the long edge to 84.00 +/-0.02 mm; the width is controlled to be 20.00 +/-0.02 mm.

And step 3: printing silver, copper and titanium active slurry on the second, third, fourth and

fifth component units

2, 3, 4 and 5: the method specifically comprises the following steps:

step 3.1: ultrasonically cleaning the second, third, fourth and

fifth component units

2, 3, 4 and 5 by cleaning solution and alcohol respectively, drying and printing;

step 3.3: after printing, the second, third, fourth and

fifth component units

2, 3, 4 and 5 are placed into an oven filled with protective gas to be dried for 30-60 min at 120 ℃;

step 4.1: as shown in fig. 5, the printed second, third, fourth and

fifth component units

2, 3, 4 and 5 are assembled with the first component unit 1, and the periphery is clamped by a limiting frame plate 6 and a cartridge clip 7;

step 4.2: putting the assembled die into a vacuum welding furnace, vacuumizing and welding, and controlling the vacuum degree to be 8 x 10^-4Pa, the highest temperature of 820 ℃, preserving the heat for 20min, then naturally cooling, and discharging when the temperature is reduced to 80 ℃;

According to the embodiment, the structural part is divided into the plurality of assembly units, and the assembly units are respectively processed, so that the flatness control of the cavity structural part can be effectively improved and controlled to be less than or equal to 0.02mm, and the requirement on the flatness in high-precision semiconductors and optical devices is met; and adopt the mode of silver-copper titanium active paste screen printing to the subassembly unit, can be within 0.05mm with the precision control, do not receive the figure to send out miscellaneous degree and influence the product precision, satisfy mass production uniformity requirement simultaneously, can direct welded fastening when the equipment moreover, need not to carry out high temperature sintering tungsten thick liquid, the electric nickel plating and reuse silver-copper welding on the aluminium nitride surface, saved the process, the cost is reduced. The AlN structural member prepared by the preparation method can be used under the conditions of high and low temperatures (-55-400 ℃), and can also meet the surface condition requirements of optical devices and semiconductor equipment due to the final multiple cleaning inspection.

Although the present description is described in terms of embodiments, not every embodiment includes only a single embodiment, and such description is for clarity only, and those skilled in the art should be able to integrate the description as a whole, and the embodiments can be appropriately combined to form other embodiments as will be understood by those skilled in the art.

Therefore, the above description is only a preferred embodiment of the present application, and is not intended to limit the scope of the present application; all changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

1. The preparation method of the aluminum nitride ceramic structural member is characterized by comprising the following steps of:

step 1: preparing AlN ceramic substrates required by the assembly units;

and 5: and (5) cleaning and checking the structural member.

2. The method of claim 1, wherein in step 2, the flatness of the processed assembly unit is less than or equal to 0.02mm, and the roughness Ra is less than 0.5 μm.

3. The method for preparing an aluminum nitride ceramic structural member according to claim 1 or 2, wherein the step of selecting the assembly unit and printing the silver-copper-titanium active paste specifically comprises:

4. The method according to claim 3, wherein the step 4 of assembling and welding the assembly units into the structural member specifically comprises:

step 4.1: assembling the assembly units obtained in the steps 2 and 3, and fixing by adopting a clamp or a heavy object during assembly;

step 4.2: after the assembly units are assembled, putting the assembly units into a vacuum welding furnace for vacuum welding, wherein the welding temperature is 750-850 ℃, and the vacuum degree is 8 x 10^-4～15*10^-4And (4) keeping the temperature within the range of Pa for 10-80 min, and naturally cooling to 80 ℃ after the temperature is kept, and discharging.

5. The method of claim 1 or 4, wherein in step 5, the structure is cleaned by one or more of acid washing, water washing and alcohol washing.

6. The method of claim 1, wherein the step 1 of preparing the ceramic substrate comprises the steps of:

7. The method of claim 6, wherein the method comprises the steps of: the AlN powder has the average particle size of 0.5-1.8 mu m, the specific surface area of 2-3.4 square meters per gram and the oxygen content of less than 0.9 percent.