CN114043606A

CN114043606A - Preparation method of ceramic substrate with island structure

Info

Publication number: CN114043606A
Application number: CN202111496479.9A
Authority: CN
Inventors: 庞锦标; 舒国劲; 韩玉成; 袁世逢; 谭天波; 窦占明; 周存龙; 李淼
Original assignee: China Zhenhua Group Yunke Electronics Co Ltd
Current assignee: China Zhenhua Group Yunke Electronics Co Ltd
Priority date: 2021-12-09
Filing date: 2021-12-09
Publication date: 2022-02-15
Anticipated expiration: 2041-12-09
Also published as: CN114043606B

Abstract

A preparation method of a ceramic substrate with an island structure belongs to the technical field of co-fired ceramics. Preparing a green ceramic substrate with a blind cavity by punching a cavity on a green ceramic sheet, laminating and performing small-pressure prepressing; island unburned bricks preparation, the blind chamber of island unburned bricks embedding china base plate, big pressure isostatic pressing, hot cutting, the binder removal sintering, thereby preparation has obtained a ceramic island structure with high position precision, can be applied to the ceramic structure spare that has island structure, products such as ceramic mould, realize the preparation of 0.5mm ~ 100mm big or small ceramic island, island shape is diversified, contain the square, the rectangle, circular and special-shaped structure, can solve at present through the suppression, modes such as slip casting are difficult to prepare the small-size, the problem of high position precision ceramic island, can save the mould cost simultaneously, the ceramic base plate of taking island structure of preparation has the shape diversification, the depth-diameter ratio is adjustable, characteristics such as processing cycle is short. The method is widely applied to the field of multilayer ceramic substrates with island structures.

Description

Preparation method of ceramic substrate with island structure

Technical Field

The invention belongs to the technical field of multilayer co-fired ceramics, and further relates to the technical field of special-shaped structure ceramics, in particular to a preparation method of a ceramic substrate with a high-position-precision island structure.

Background

The multilayer co-fired ceramic (including LTCC and HTCC) technology is that ceramic powder is made into a green ceramic tape with accurate thickness and compactness, each layer of circuit pattern is made on the green ceramic tape by utilizing the processes of laser drilling, micropore grouting, precise conductor paste printing and the like, and then a ceramic substrate or a circuit board with a three-dimensional structure is prepared in a multilayer contraposition stacking mode. Because only cavities (the area of the cavities is usually required to be 1/2 not exceeding the total area of the green ceramic chips) can be prepared on each layer of the green ceramic chips, and the edges of the cavities are required to be connected with the green ceramic chips with certain strength and cannot be isolated islands, otherwise, the cavities cannot be laminated. Therefore, in the prior art, the ceramic substrate processed based on the LTCC/HTCC process platform only has a cavity structure, and an island boss with high position precision and high size precision cannot be prepared.

With the rapid development of electronic science and technology, the demand of electronic components, systems and the like on high-precision miniaturized ceramic substrate products is continuously increased, the ceramic substrates with the requirements of miniaturization and high precision are difficult to prepare by adopting injection molding, compression molding and other modes, and meanwhile, the problems of long mold opening period, high cost and the like exist.

In view of the above, the present invention is particularly proposed.

Disclosure of Invention

The purpose of the invention is: the problem that island bosses cannot be prepared based on the LTCC/HTCC process technology in the prior art is solved.

The invention provides a method for preparing a ceramic substrate with an island structure, wherein the ceramic substrate with the island structure consists of a cavity structure green ceramic body (A) and a boss green body (B), the boss is an independent ceramic block without overlapped protrusions on the periphery, the green ceramic body with a blind cavity is prepared by adopting the steps of cavity forming, lamination, small-pressure prepressing and the like on a green ceramic chip based on a multilayer co-fired ceramic (including LTCC and HTCC) technology, the boss green body with the blind cavity is prepared by adopting the steps of green ceramic chip lamination, small-pressure prepressing cutting (pressure 500 PSi-2000 PSi), laser and the like, finally, the island green body is embedded into the blind cavity of the green ceramic substrate, the steps of large-pressure isostatic pressing (pressure 3000 PSi-10000 PSi), hot cutting, glue discharging sintering and the like, the ceramic island structure with high position precision is prepared, the shape of the blind cavity is consistent with the shape of the island B, the plane size of the blind cavity is slightly larger than that of the B island, and the thickness of the B island is required to be larger than the depth of the part A of the blind cavity, so that the B island is accurately positioned and nested in the blind cavity.

The preparation method of the ceramic substrate with the island structure comprises the following specific steps:

(1) b, preparing an island boss blank: b is a protruding island part on the ceramic substrate, and a green body of the island B is prepared by the steps of laminating on a green ceramic chip, pre-isostatic pressing with small pressure, cutting and the like;

(2) a, preparing a green porcelain body with a concave cavity structure: a is the other part on the ceramic substrate, and is prepared by punching a positioning hole, punching a cavity, laminating, carrying out small-pressure pre-isostatic pressing and the like on the green ceramic chip, wherein the substrate A is provided with a blind cavity structure, the shape of the blind cavity is consistent with that of the B island, the plane size of the blind cavity is slightly larger than that of the B island, and the height range of the blind cavity is 0.1-1 mm.

(3) Spraying thin-layer ethanol in the blind cavity of the substrate A in a spraying mode and the like, and plugging the green body of the island B obtained by cutting into the blind cavity of the substrate A;

(4) according to the characteristics of the island B, such as height, shape and the like, selecting a proper protection mold, and carrying out vacuum packaging, high-pressure isostatic pressing, hot cutting, binder removal and sintering on the green body of the substrate A + B to obtain the ceramic substrate with the island structure;

optionally, the part a is a main substrate part: multilayer ceramic structures, typically 0.5mm to 5mm thick and typically of a size compatible with LTCC/HTCC process platforms, typically 152.4mm or 203 mm;

optionally, the part B is an island part to be prepared on the substrate a: the size of the multilayer ceramic structure is determined by design, generally ranges from 1mm to 50mm, the shape is diversified, the multilayer ceramic structure comprises square, rectangular, round and special-shaped structures, and the thickness is generally ranges from 0.5mm to 10 mm.

Optionally, the specific processing principle of the blind cavity of the main substrate a is to identify a mechanical or laser-processed positioning hole, and then prepare the blind cavity by conventional laser cavity-forming, laminating and pre-isostatic pressing process steps; the specific processing principle of the part B appearance structure is that the part B appearance structure is prepared by the steps of laminating, pre-isostatic pressing and cutting of conventional green ceramic chips.

Optionally, A, B partial pre-isostatic pressing process parameters are: the water temperature is 60-80 ℃, the pressure is 500-2000 PSi, and the pressure maintaining time is 2-10 min.

Optionally, when the part a is processed, a piece of PET film with a blind cavity pattern needs to be stacked on the upper surface (where an island surface needs to be prepared), when the film is stacked on the plate a, only the blind cavity part of the part a is exposed, and the other part of the part a is protected and covered by the PET film.

Optionally, the cutting of the part B may be performed by milling cutter mechanical cutting, laser cutting, blade mechanical cutting, and the like, the prepared part B has a shape structure consistent with the blind cavity of the substrate a, and the thickness of the part B needs to be greater than the depth of the blind cavity of the part a.

Optionally, for the same product, there are only 1 type of substrate part a, and the island part B can have various forms: b1, B2, B3 and the like, the shape or height of each island is different, and the blind cavities on the A substrate correspond to the B islands one by one.

Optionally, under the protection effect of the PET film, a thin layer of ethanol can be sprayed in the blind cavity B by spraying and the like, the thickness of the ethanol is required to be less than 50 μm, after the ethanol is sprayed, the PET film is torn off within a time range of 30 seconds, and all the cut islands of B (including B1, B2 and B3 …) are correspondingly plugged into the blind cavity of the substrate a one by one.

Optionally, before the green body with the A + B combination is subjected to high-pressure isostatic pressing, different molds need to be selected for protection according to the difference between the height and the size ratio (diameter-depth ratio) of the island B, when the diameter-depth ratio is less than 2, a rigid mold is recommended to be selected for protecting the island, when the diameter-depth ratio is greater than 5, an organic elastic mold can be selected, and both the middle part and the middle part can be selected. After the island and the cavity of the substrate A are well protected by using a mold, vacuum packaging, isostatic pressing, hot cutting and binder removal sintering are carried out, wherein the isostatic pressing process parameters are as follows: the water temperature is 60-80 ℃, the pressure is 3000 PSi-10000 PSi, and the pressure maintaining time is 20-60 min.

Optionally, parameters such as a green body binder removal sintering curve and sintering atmosphere with a + B combination are determined according to ceramic material components, the sintering temperature range is usually 700-1800 ℃, and the sintered a and B form a seamless connection whole.

Compared with the prior art, the invention has the beneficial effects that:

according to the invention, the concave-convex cavities are matched with each other, the preparation of the ceramic island with the size of 0.5-100 mm is realized, the island shape is diversified and comprises square, rectangular, round and special-shaped structures, the problem that the small-size and high-position precision ceramic island is difficult to prepare in the conventional modes of pressing, grouting and the like can be solved, the cost of a mold can be saved, and the prepared ceramic substrate with the island structure has the advantages of diversified shape, adjustable depth-diameter ratio, short processing period and the like.

Drawings

FIG. 1 is a schematic structural diagram of a multi-layer alumina substrate product with an island structure.

In the figure: a is a concave cavity structure substrate, and B is an island.

Detailed Description

Taking the preparation of the high-temperature multilayer co-fired alumina substrate with an island structure as an example, the detailed description of the embodiment is as follows:

(1) preparing the raw ceramic chip

The conventional process technologies of ball milling, pulping, tape casting, cutting and the like are adopted to prepare 99.6 percent alumina green tiles 4 (respectively named as A1, A2, B1 and B2) with the thickness of 0.7mm (0.5 mm after sintering) and the size of 203mm x 203 mm.

(2) Laser machining and pre-lamination

Processing arrayed square through cavities with the size of 7.05mm by 7.05mm on the green ceramic chip A1 by adopting a laser processing mode, and laminating the green ceramic chips A1 and A2 and B1 and B2 with the cavities. After the packaging is finished, isostatic pressing is respectively carried out on two bars of A1+ A2 and B1+ B2 to respectively obtain green A (A1+ A2) and B (B1+ B2) bodies, the water temperature is 65 ℃, the pressure is 1500Psi, and the dwell time is 5 min.

(3) Laser cutting

And processing the pre-pressed B-shaped raw porcelain by adopting an ultraviolet nanosecond laser drilling machine to process square pieces of an array type, wherein the size of each square piece is 7mm by 7mm, and a circular hole of 0.5mm is processed in the middle of each square piece.

(4) Boss stack

Spraying absolute ethyl alcohol in a prepressing round cavity (7.05mm) of A through an atomizer, putting a wafer of 7mm into the round cavity, drying at 60 ℃, then carrying out packaging isostatic pressing, keeping the pressure for 30min at 65 ℃ and 7000Psi, and cutting the wafer into square wafers of 16mm x 16mm according to cutting lines after pressing.

(5) Binder removal sintering

Sintering the square sheet in a high-temperature sintering furnace at the maximum temperature of 1680 ℃ for 2h to obtain the alumina ceramic part with the boss, wherein the boss precision is less than 20 mu m as shown in figure 1.

The foregoing is a further detailed description of the invention in connection with preferred embodiments and is not intended to limit the invention to the precise form disclosed. It will be understood by those skilled in the art that various changes in detail may be effected therein without departing from the scope of the invention as defined by the appended claims.

Claims

1. A preparation method of a ceramic substrate with an island structure is characterized by comprising the following specific steps:

(1) preparing a B island green body with a boss by laminating, pre-isostatic pressing under low pressure and cutting on a green ceramic wafer;

(2) preparing a green ceramic blank A substrate with a concave cavity structure by punching a positioning hole, punching a cavity, laminating and small-pressure pre-isostatic pressing on a green ceramic sheet, wherein the substrate A is provided with a blind cavity structure, the shape of the blind cavity is consistent with that of the B island, the plane size of the blind cavity is slightly larger than that of the B island, and the height range of the blind cavity is 0.1-1 mm;

(3) spraying thin-layer ethanol in the blind cavity of the substrate A in a spraying mode, and plugging a green body of the island B obtained by cutting into the blind cavity of the substrate A;

(4) according to the difference of the diameter-depth ratio of the height and the size of the island B, different molds are selected for protection, when the diameter-depth ratio is less than 2, a rigid mold is selected for protecting the island, when the diameter-depth ratio is greater than 5, an organic elastic mold is selected, and both the molds can be used in the middle part;

(5) carrying out vacuum packaging, high-pressure isostatic pressing, hot cutting and binder removal sintering on the green body of the A + B combined substrate to obtain a ceramic substrate with an island structure; the isostatic pressing technological parameters are as follows: the water temperature is 60-80 ℃, the pressure is 3000 PSi-10000 PSi, and the pressure maintaining time is 20-60 min; the sintering temperature range of the green body of the A + B combined substrate is 700-1800 ℃, and the sintered A and B form a seamless connection whole.

2. The method according to claim 1, wherein A is a multilayer ceramic structure with a thickness of 0.5mm to 5mm and a size of 152.4mm or 203 mm.

3. The method for preparing a ceramic substrate with an island structure according to claim 1, wherein B is a multilayer ceramic structure with a size of 1mm to 50mm, a square, rectangular, circular or irregular structure and a thickness of 0.5mm to 10 mm.

4. The method for preparing a ceramic substrate with an island structure according to claim 1, wherein the blind cavity of A is prepared by identifying a mechanical or laser-processed positioning hole and then by conventional laser cavity-punching, laminating and pre-isostatic pressing process steps, in the preparation process, a PET film punched with a blind cavity pattern is laminated on one surface of the island to be prepared, only the blind cavity part of A is exposed, and other parts of A are protected and covered by the PET film;

the boss island of the part B is prepared by the conventional green ceramic chip laminating, pre-isostatic pressing and cutting processes, cutting is carried out by a milling cutter mechanical cutting, laser cutting or blade mechanical cutting mode, the prepared part B has the same appearance structure as the blind cavity of the part A, and the thickness of the part B is required to be larger than the depth of the blind cavity of the part A.

5. The method for preparing a ceramic substrate with an island structure according to claim 1, wherein the pre-isostatic pressing process parameters of A or B are as follows: the water temperature is 60-80 ℃, the pressure is 500-2000 PSi, and the pressure maintaining time is 2-10 min.

6. The method according to claim 1, wherein the substrate part A has only 1 type, the island part B has islands with different shapes or heights, and the blind cavities on the substrate A correspond to the island part B one by one;

and under the protection action of the PET film, spraying a thin layer of ethanol in the blind cavity B in a spraying mode, wherein the thickness of the ethanol is less than 50 microns, tearing off the PET film within 30 seconds after the ethanol is sprayed, and correspondingly plugging all cut isolated islands B into the blind cavity of the substrate A one by one.

7. The method for preparing a ceramic substrate with an island structure according to claim 1, wherein the specific preparation process comprises the following steps:

(1) preparing a green ceramic chip:

preparing 4 pieces of 99.6 percent alumina green ceramic chips with the thickness of 0.7mm and the size of 203mm by adopting conventional process technologies such as ball milling, pulping, tape casting, cutting and the like, wherein the ceramic chips are respectively named as A1, A2, B1 and B2;

(2) laser processing and pre-laminating:

processing arrayed square through cavities with the size of 7.05mm by 7.05mm on a green ceramic chip A1 by adopting a laser processing mode, laminating the green ceramic chips A1 and A2 with the cavities to obtain an A1+ A2 bar block, laminating B1 and B2 to obtain a B1+ B2 bar block, and respectively carrying out isostatic pressing on the A1+ A2 bar block and the B1+ B2 bar block to respectively obtain an A green body and a B green body; the technological parameters of the isostatic pressing are that the water temperature is 65 ℃, the pressure is 1500Psi, and the pressure maintaining time is 5 min;

(3) laser cutting:

processing the pre-pressed B green body by adopting an ultraviolet nanosecond laser drilling machine, processing array type square sheets with the size of 7mm by 7mm, and processing a circular hole with the size of 0.5mm in the middle of each square sheet;

(4) stacking the bosses:

in a 7.05mm prepressing circular cavity of A, spraying absolute ethyl alcohol through an atomizer, putting a 7mm wafer into the circular cavity, drying at 60 ℃, and then packaging and isostatic pressing, wherein the technological parameters of the isostatic pressing are as follows: cutting into square pieces of 16mm by 16mm according to cutting lines after pressing at 65 deg.C under 7000Psi for 30 min;

(5) and (3) binder removal and sintering:

sintering the square plate in a high-temperature sintering furnace at the sintering temperature of 1680 ℃ for 2 hours to obtain the alumina ceramic part with the boss, wherein the boss precision is less than 20 mu m as shown in figure 1.