Preparation method and material of a copper conductive film with high shrinkage rate

Abstract

The present invention relates to the technical field of copper conductive film preparation, and relates to a preparation method and material of a copper conductive film with a high shrinkage rate, including: preparing a conductive precursor material, an organic solution precursor material, and an inorganic precursor material; mixing the conductive precursor material, the inorganic precursor material and the organic solution precursor material, coating the sintered conductive copper paste obtained by water bath heating on the surface of a ceramic substrate, performing vacuum defoaming treatment and vacuum leveling treatment, and placing the obtained sintered conductive copper paste coating leveling assembly in a protective atmosphere for debinding heat treatment and curing heat treatment to obtain a copper conductive film material with a high shrinkage rate. The present invention can prepare a copper conductive film material with a high shrinkage rate, low resistivity and high bonding strength.

Description

Technical Field

[0001] The present invention relates to the technical field of copper conductive films, and particularly to a preparation method and material of a copper conductive film with a high shrinkage rate. Background Art

[0002] Sintered conductive copper paste has the advantages of low cost, high electrical and thermal conductivity, good printing leveling property, low electron mobility, etc., and is the preferred conductive material for preparing printed ceramic circuit boards (PCBs) and multi-layer ceramic capacitors (MLCCs). After high-temperature sintering, the conductive copper paste forms a copper conductive film, and its properties mainly include resistivity and bonding strength with the substrate. At present, the focus of research on copper conductive films is to reduce the resistivity. To meet the requirements of industrial applications, a series of technologies have been developed to improve the performance of copper conductive films. Currently, the main methods for reducing the resistivity include the following three: one is to increase the proportion of conductive copper powder to exceed its percolation threshold; the second is to introduce copper powder with a smaller size, such as nano-sized copper powder; the third is to improve the sintering process to increase the debinding rate of the organic precursor to improve the bonding between copper powders. The above methods have achieved certain effects in the research of reducing the resistivity of copper conductive films, but there are still the following limitations: 1) Too high a proportion of copper powder will affect the proportion of the organic precursor and the inorganic binder precursor, resulting in a decrease in its printability, leveling property and bonding force with the substrate, so the room for increasing the proportion of copper powder is limited; 2) Nano-sized copper powder has a low melting point and is easy to sinter, which is suitable for the preparation of copper conductive films, but it is costly and not conducive to large-scale applications in the industrial field; 3) Improving the sintering process to increase the debinding rate may lead to the formation of a large number of pores inside the copper conductive film, thus limiting the reduction of the resistivity.

[0003] Therefore, how to overcome the deficiencies in the traditional methods and further reduce the resistivity of copper conductive films has become an urgent problem to be solved. Summary of the Invention

[0004] In view of this, in order to overcome the deficiencies of the prior art, the present invention provides a preparation method and material of a copper conductive film with a high shrinkage rate.

[0005] On the one hand, the present invention provides a preparation method of a copper conductive film with a high shrinkage rate, and the method includes:

[0006] Step 1: Preparation of copper paste precursor materials

[0007] Mix atomized copper powder and reduced copper powder according to the ratio to prepare a conductive precursor material;

[0008] Mix terpineol, ethyl cellulose, polyvinylpyrrolidone K30, polyethylene glycol 200, paraffin wax, and polyoxypropylene according to the ratio to obtain an organic mixed solution, and stir the obtained organic mixed solution under the condition of water bath heating to obtain an organic solution precursor material;

[0009] Mix bismuth oxide, neutral alumina, boric anhydride, and manganese dioxide according to the ratio to obtain an inorganic mixed powder. After sintering the obtained inorganic mixed powder, perform a refinement treatment to obtain an inorganic precursor material.

[0010] Step Two: Preparation of Sintered Conductive Copper Paste

[0011] Mix the conductive precursor material, inorganic precursor material, and organic solution precursor material according to the ratio, and stir evenly under the condition of water bath heating to obtain a sintered conductive copper paste.

[0012] Step Three: Coating and Levelling Treatment of Sintered Conductive Copper Paste

[0013] Evenly coat the sintered conductive copper paste on the surface of the ceramic substrate, and successively perform vacuum defoaming treatment and vacuum levelling treatment on the ceramic substrate coated with the sintered copper paste to obtain a sintered conductive copper paste coating and levelling assembly.

[0014] Step Four: Forming Heat Treatment of Copper Conductive Film

[0015] Place the sintered conductive copper paste coating and levelling assembly in a protective atmosphere for debinding heat treatment and curing heat treatment to obtain a copper conductive film material with a high shrinkage rate.

[0016] Preferably, in the preparation method of the copper conductive film with a high shrinkage rate of the present invention, in step one, the average particle size of the atomized copper powder is 3 - 5 μm, the average particle size of the reduced copper powder is 0.5 - 1 μm, and the conductive precursor material contains 70 - 90 wt.% of atomized copper powder; the weight ratio of terpineol, ethyl cellulose, polyvinylpyrrolidone K30, polyethylene glycol 200, paraffin wax, and polyoxypropylene is 85:5:3:3:2:2; the weight ratio of bismuth oxide, neutral alumina, boric anhydride, and manganese dioxide is 55 - 70:15:15:5.

[0017] Preferably, in the preparation method of the copper conductive film with a high shrinkage rate of the present invention, in step one, the temperature of the water bath heating is 80°C, and the stirring treatment time is 1 h.

[0018] Preferably, in the preparation method of the copper conductive film with a high shrinkage rate of the present invention, in step one, the sintering treatment includes: roll-mill the obtained inorganic mixed powder for 12 h and then heat it to 900 - 1200°C, hold for 1 h, and cool in air.

[0019] Preferably, in the preparation method of the copper conductive film with a high shrinkage rate of the present invention, in step one, the refinement treatment includes: ball-mill the sintered inorganic mixed powder for 24 h under the condition that the ball-to-material ratio is 15:1, and screen the material after ball-milling with a 200-mesh sieve to obtain an inorganic precursor material.

[0020] Preferably, in the preparation method of the high shrinkage rate copper conductive film of the present invention, step two includes: roll-milling and mixing 72-78 parts by weight of a conductive precursor material and 8-12 parts by weight of an inorganic precursor material for 6 hours, mixing the obtained roll-milled and mixed material with 14-18 parts by weight of an organic solution precursor material, and then magnetically stirring for 2 hours under the condition of water bath heating at 60°C to obtain a sintered conductive copper paste.

[0021] Preferably, in step three of the preparation method of the high shrinkage rate copper conductive film of the present invention, uniformly coating the sintered conductive copper paste on the surface of a ceramic substrate includes: printing the sintered copper paste on the surface of the ceramic substrate using a wire mesh with a pore size of 200 meshes. The ceramic substrate is made of alumina material with a purity of not less than 99%, and the average surface roughness of the ceramic substrate is not greater than Ra0.8.

[0022] Preferably, in step three of the preparation method of the high shrinkage rate copper conductive film of the present invention, sequentially performing vacuum defoaming treatment and vacuum leveling treatment on the ceramic substrate coated with the sintered copper paste includes: using a vacuum bubble extraction machine to perform vacuum defoaming treatment on the ceramic substrate coated with the sintered copper paste for 2 hours, and heating the ceramic substrate coated with the sintered copper paste after vacuum defoaming treatment to 80°C in a vacuum and holding for 20 minutes.

[0023] Preferably, in step four of the preparation method of the high shrinkage rate copper conductive film of the present invention, includes: placing the sintered conductive copper paste coating and leveling assembly in a protective atmosphere, heating it at a heating rate of 2°C / min to 700°C and then holding for 2-5 hours, and then heating it at a heating rate of 5°C / min to 750-900°C and holding for 1-2 hours to obtain a high shrinkage rate copper conductive film material.

[0024] On the other hand, the present invention provides a high shrinkage rate copper conductive film material, which is prepared according to the above method.

[0025] The preparation method and material of the high shrinkage rate copper conductive film of the present invention have the following beneficial effects:

[0026] 1. By preparing the conductive precursor material, the adhesiveness during the sintering of the conductive copper paste is improved, so that the sintered conductive copper paste has a higher shrinkage rate and lower resistivity after high-temperature sintering;

[0027] 2. By preparing the organic solution precursor material, the conductive copper paste shrinks under high-temperature sintering to form a denser conductive path, effectively reducing the resistivity and realizing the shrinkage of the sintered conductive copper paste at high temperature;

[0028] 3. By preparing the inorganic precursor material, the fluidity of the conductive paste during the curing process is improved, the internal density of the conductive copper paste is higher, the resistivity is reduced, and the bonding strength between the copper paste and the substrate is increased.

[0029] The copper conductive thin film material with a high shrinkage rate prepared by the present invention has a high shrinkage rate, a uniform and flat surface, low resistivity and high bonding strength, and can meet the requirements of printed ceramic circuit boards (PCBs) and multilayer ceramic capacitors (MLCCs) for the conductivity and bonding strength of conductive pastes. Brief Description of the Drawings

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0031] Figure 1 It is a schematic flow chart of the preparation method of the copper conductive thin film with a high shrinkage rate for exemplary embodiments 1-8 of the present invention;

[0032] Figure 2 It is a macroscopic image of the copper conductive thin film material with a high shrinkage rate prepared according to the method embodiment of the present invention and the copper conductive thin film material prepared in the comparative example;

[0033] Figure 3 It is a SEM micrograph of the copper conductive thin film material with a high shrinkage rate prepared in embodiments 1-8 of the present invention and the copper conductive thin film material prepared in embodiment 9 (comparative example);

[0034] Figure 4 It is an EDS spectrum of the copper conductive thin film material with a high shrinkage rate prepared in embodiment 3 of the present invention;

[0035] Figure 5 It is an EDS spectrum of the copper conductive thin film material with a high shrinkage rate prepared in embodiment 4 of the present invention;

[0036] Figure 6 It is an EDS spectrum of the copper conductive thin film material with a high shrinkage rate prepared in embodiment 8 of the present invention;

[0037] Figure 7 It is a DSC curve of the atomized copper powder in embodiments 1-8 of the present invention and the comparative example;

[0038] Figure 8 It is a DSC curve of the reduced copper powder in embodiments 1-8 of the present invention;

[0039] Figure 9 It is a DSC curve of the inorganic precursor in embodiments 1-6 of the present invention;

[0040] Figure 10 This is the DSC curve of the inorganic precursor in Example 8 of the present invention. Detailed implementation manners

[0041] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0042] It should be noted that, without conflict, the following embodiments and the features in the embodiments may be combined with each other; and, based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present disclosure.

[0043] It should be noted that the following describes various aspects of the embodiments within the scope of the appended claims. It should be apparent that the aspects described herein may be embodied in a wide variety of forms, and any specific structure and / or function described herein is illustrative only. Based on the present disclosure, those skilled in the art should understand that one aspect described herein may be implemented independently of any other aspect, and two or more of these aspects may be combined in various ways. For example, any number of aspects described herein may be used to implement the device and / or practice the method. In addition, this device may be implemented and this method may be practiced using other structures and / or functions in addition to one or more of the aspects described herein.

[0044] By introducing reducible copper powder that is easy to sinter, preparing a new inorganic precursor with a high heat flux value, and improving the organic precursor and other comprehensive measures, the present invention makes the copper conductive film shrink while increasing the debinding rate, reduces the porosity of the copper conductive film and improves its internal denseness and uniformity, thereby further reducing the resistivity of the copper conductive film to meet the preparation requirements of PCBs and MLCCs. Figure 1 This is a schematic flowchart of the method for preparing a high shrinkage rate copper conductive film according to Exemplary Embodiments 1-8 of the present invention. Embodiments 1 to 8 of the present invention are implemented in the Figure 1 manner shown.

[0045] Example 1

[0046] Preparation of a high shrinkage rate copper conductive film:

[0047] Step 1. Preparation of the copper paste precursor material

[0048] Mix atomized copper powder and reducible copper powder according to the ratio to prepare the conductive precursor material. The average particle size of the atomized copper powder is 3-5 μm, the average particle size of the reducible copper powder is 0.5-1 μm, and the conductive precursor material contains 90 wt.% of atomized copper powder;

[0049] Mix terpineol, ethyl cellulose, polyvinylpyrrolidone K30, polyethylene glycol 200, paraffin wax, and polyoxypropylene in a ratio of 85:5:3:3:2:2 by weight to obtain an organic mixed solution. Stir the obtained organic mixed solution for 1 h under the condition of water bath heating at 80 °C to obtain an organic solution precursor material;

[0050] Mix bismuth oxide, neutral alumina, boric anhydride, and manganese dioxide in a ratio of 70:15:15:5 by weight to obtain an inorganic mixed powder. After roll milling the obtained inorganic mixed powder for 12 h, heat it to 900 °C, keep it warm for 1 h, and then air cool it; Under the condition that the ball-to-material ratio is 15:1, ball mill the sintered inorganic mixed powder for 24 h, and screen the milled material with a 200-mesh sieve to obtain an inorganic precursor material;

[0051] Step 2. Preparation of sintered conductive copper paste

[0052] Roll mill and mix 78 parts by weight of the conductive precursor material and 8 parts by weight of the inorganic precursor material for 6 h. Mix the obtained roll milled and mixed material with 14 parts by weight of the organic solution precursor material, and then place it under the condition of water bath heating at 60 °C and stir magnetically for 2 h to obtain a sintered conductive copper paste;

[0053] Step 3. Coating and leveling treatment of sintered conductive copper paste

[0054] Print the sintered copper paste on the surface of a ceramic substrate by using a wire mesh with a pore size of 200 mesh. The ceramic substrate is made of alumina material with a purity of not less than 99%, and the average surface roughness of the ceramic substrate is not greater than Ra0.8; Use a vacuum degassing machine to perform a 2-h vacuum degassing treatment on the ceramic substrate coated with the sintered conductive copper paste, and place the ceramic substrate coated with the sintered conductive copper paste after vacuum degassing treatment in a vacuum and heat it to 80 °C and keep it warm for 20 min to obtain a sintered conductive copper paste coating and leveling assembly;

[0055] Step 4. Forming heat treatment of copper conductive film

[0056] Place the sintered conductive copper paste coating and leveling assembly in a protective atmosphere, heat it to 700 °C at a heating rate of 2 °C / min and then keep it warm for 2 h, and then heat it to 750 °C at a heating rate of 5 °C / min and keep it warm for 1 h to obtain a copper conductive film material with a high shrinkage rate.

[0057] Example 2

[0058] Preparation of copper conductive film with high shrinkage rate:

[0059] Step 1. Preparation of copper paste precursor material

[0060] Mix atomized copper powder and reduced copper powder according to the ratio to prepare a conductive precursor material. The average particle size of the atomized copper powder is 3 - 5 μm, the average particle size of the reduced copper powder is 0.5 - 1 μm, and the conductive precursor material contains 90 wt.% atomized copper powder;

[0061] Mix terpineol, ethyl cellulose, polyvinylpyrrolidone K30, polyethylene glycol 200, paraffin wax, and polyoxypropylene in a weight ratio of 85:5:3:3:2:2 to obtain an organic mixed solution. Stir the obtained organic mixed solution for 1 h under the condition of water bath heating at 80 °C to obtain an organic solution precursor material;

[0062] Mix bismuth oxide, neutral alumina, boric anhydride, and manganese dioxide in a weight ratio of 70:15:15:5 to obtain an inorganic mixed powder. After roller milling the obtained inorganic mixed powder for 12 h, heat it to 900 °C, keep it warm for 1 h, and then air cool it; Under the condition of a ball-to-material ratio of 15:1, ball mill the sintered inorganic mixed powder for 24 h, and screen the milled material with a 200-mesh sieve to obtain an inorganic precursor material;

[0063] Step 2: Preparation of sintered conductive copper paste

[0064] Roller mill and mix 74 parts by weight of the conductive precursor material and 12 parts by weight of the inorganic precursor material for 6 h. Mix the obtained roller milled mixture with 14 parts by weight of the organic solution precursor material, and then place it under the condition of water bath heating at 60 °C and stir magnetically for 2 h to obtain a sintered conductive copper paste;

[0065] Step 3: Coating and leveling treatment of the sintered conductive copper paste

[0066] Print the sintered copper paste on the surface of a ceramic substrate using a 200-mesh screen. The ceramic substrate is made of alumina material with a purity of not less than 99%, and the average surface roughness of the ceramic substrate is not greater than Ra0.8; Use a vacuum degassing machine to perform a 2-h vacuum degassing treatment on the ceramic substrate coated with the sintered copper paste, and place the ceramic substrate coated with the sintered copper paste after vacuum degassing in a vacuum and heat it to 80 °C and keep it warm for 20 min to obtain a sintered conductive copper paste coating and leveling assembly;

[0067] Step 4: Heat treatment for forming a copper conductive film

[0068] Place the sintered conductive copper paste coating and leveling assembly in a protective atmosphere, heat it to 700 °C at a heating rate of 2 °C / min and then keep it warm for 3 h, and then heat it to 750 °C at a heating rate of 5 °C / min and keep it warm for 1 h to obtain a copper conductive film material with a high shrinkage rate.

[0069] Example 3

[0070] Preparation of High Shrinkage Copper Conductive Film:

[0071] Step 1: Preparation of Copper Paste Precursor Materials

[0072] Mix atomized copper powder and reduced copper powder according to the ratio to prepare a conductive precursor material. The average particle size of the atomized copper powder is 3 - 5 μm, and the average particle size of the reduced copper powder is 0.5 - 1 μm. The conductive precursor material contains 90 wt.% atomized copper powder;

[0073] Mix terpineol, ethyl cellulose, polyvinylpyrrolidone K30, polyethylene glycol 200, paraffin wax, and polyoxypropylene in a weight ratio of 85:5:3:3:2:2 to obtain an organic mixed solution. Stir the obtained organic mixed solution for 1 h under the condition of water bath heating at 80 °C to obtain an organic solution precursor material;

[0074] Mix bismuth oxide, neutral alumina, boric anhydride, and manganese dioxide in a weight ratio of 70:15:15:5 to obtain an inorganic mixed powder. After roll-milling the obtained inorganic mixed powder for 12 h, heat it to 900 °C, keep it warm for 1 h, and then air-cool it; Under the condition of a ball-to-material ratio of 15:1, ball-mill the sintered inorganic mixed powder for 24 h, and screen the ball-milled material with a 200-mesh sieve to obtain an inorganic precursor material;

[0075] Step 2: Preparation of Sintered Conductive Copper Paste

[0076] Roll-mill and mix 72 parts by weight of the conductive precursor material and 10 parts by weight of the inorganic precursor material for 6 h. After mixing the obtained roll-milled mixture with 18 parts by weight of the organic solution precursor material, place it under the condition of water bath heating at 60 °C and magnetically stir for 2 h to obtain a sintered conductive copper paste;

[0077] Step 3: Coating and Leveling Treatment of Sintered Conductive Copper Paste

[0078] Print the sintered copper paste on the surface of a ceramic substrate using a 200-mesh screen. The ceramic substrate is made of alumina material with a purity of not less than 99%, and the average surface roughness of the ceramic substrate is not greater than Ra0.8; Use a vacuum degassing machine to perform a 2-h vacuum degassing treatment on the ceramic substrate coated with the sintered copper paste. Place the ceramic substrate coated with the sintered copper paste after vacuum degassing treatment in a vacuum and heat it to 80 °C for 20 min to obtain a sintered conductive copper paste coating and leveling assembly;

[0079] Step 4: Forming Heat Treatment of Copper Conductive Film

[0080] Place the sintered conductive copper paste coating and leveling component in a protective atmosphere, heat it to 700 °C at a heating rate of 2 °C / min and then hold for 4 h, and then heat it to 750 °C at a heating rate of 5 °C / min and hold for 1 h to obtain a copper conductive thin film material with a high shrinkage rate.

[0081] Example 4

[0082] Preparation of copper conductive thin film with high shrinkage rate:

[0083] Step 1. Preparation of copper paste precursor materials

[0084] Mix atomized copper powder and reduced copper powder according to the ratio to prepare a conductive precursor material. The average particle size of the atomized copper powder is 3 - 5 μm, and the average particle size of the reduced copper powder is 0.5 - 1 μm. The conductive precursor material contains 90 wt.% of atomized copper powder;

[0085] Mix terpineol, ethyl cellulose, polyvinylpyrrolidone K30, polyethylene glycol 200, paraffin, and polyoxypropylene in a weight ratio of 85:5:3:3:2:2 to obtain an organic mixed solution, and stir the obtained organic mixed solution for 1 h under the condition of water bath heating at 80 °C to obtain an organic solution precursor material;

[0086] Mix bismuth oxide, neutral alumina, boric anhydride, and manganese dioxide in a weight ratio of 70:15:15:5 to obtain an inorganic mixed powder. After roller milling the obtained inorganic mixed powder for 12 h, heat it to 900 °C, hold for 1 h, and cool it in air; under the condition of a ball-to-material ratio of 15:1, ball mill the sintered inorganic mixed powder for 24 h, and screen the ball-milled material with a 200-mesh sieve to obtain an inorganic precursor material;

[0087] Step 2. Preparation of sintered conductive copper paste

[0088] Roller mill and mix 72 parts by weight of the conductive precursor material and 10 parts by weight of the inorganic precursor material for 6 h, mix the obtained roller-milled mixture with 18 parts by weight of the organic solution precursor material, and then place it under the condition of water bath heating at 60 °C and magnetically stir for 2 h to obtain a sintered conductive copper paste;

[0089] Step 3. Coating and leveling treatment of sintered conductive copper paste

[0090] A wire mesh with a pore size of 200 meshes is used to print the sintered copper paste on the surface of the ceramic substrate. The ceramic substrate is made of alumina material with a purity of not less than 99%, and the average surface roughness of the ceramic substrate is not greater than Ra0.8. A vacuum bubble extractor is used to perform a 2-hour vacuum defoaming treatment on the ceramic substrate coated with the sintered copper paste. The ceramic substrate coated with the sintered copper paste after the vacuum defoaming treatment is placed in a vacuum and heated to 80 °C and held for 20 minutes to obtain a sintered conductive copper paste-coated and leveled component.

[0091] Step 4: Heat treatment for forming the copper conductive film

[0092] The sintered conductive copper paste-coated and leveled component is placed in a protective atmosphere and heated to 700 °C at a heating rate of 2 °C / min and held for 5 h, and then heated to 800 °C at a heating rate of 5 °C / min and held for 1.5 h to obtain a copper conductive film material with a high shrinkage rate.

[0093] Example 5

[0094] Preparation of the copper conductive film with a high shrinkage rate:

[0095] Step 1: Preparation of the copper paste precursor material

[0096] The atomized copper powder and reduced copper powder are mixed according to the ratio to prepare the conductive precursor material. The average particle size of the atomized copper powder is 3 - 5 μm, the average particle size of the reduced copper powder is 0.5 - 1 μm, and the conductive precursor material contains 80 wt.% of the atomized copper powder.

[0097] Terpineol, ethyl cellulose, polyvinylpyrrolidone K30, polyethylene glycol 200, paraffin, and polyoxypropylene are mixed according to the weight ratio of 85:5:3:3:2:2 to obtain an organic mixed solution. The obtained organic mixed solution is stirred for 1 h under the condition of water bath heating at 80 °C to obtain the organic solution precursor material.

[0098] Bismuth oxide, neutral alumina, boric anhydride, and manganese dioxide are mixed according to the weight ratio of 70:15:15:5 to obtain an inorganic mixed powder. The obtained inorganic mixed powder is roll-milled for 12 h and then heated to 900 °C, held for 1 h, and air-cooled. Under the condition of a ball-to-material ratio of 15:1, the sintered inorganic mixed powder is ball-milled for 24 h, and the ball-milled material is screened using a 200-mesh sieve to obtain the inorganic precursor material.

[0099] Step 2: Preparation of the sintered conductive copper paste

[0100] 72 parts by weight of a conductive precursor material and 10 parts by weight of an inorganic precursor material are roll-milled and mixed for 6 h. The obtained roll-milled and mixed material is mixed with 18 parts by weight of an organic solution precursor material and then placed under magnetic stirring at 60 °C in a water bath for 2 h to obtain a sintered conductive copper paste.

[0101] Step 3: Coating and leveling treatment of the sintered conductive copper paste

[0102] The sintered copper paste is printed on the surface of a ceramic substrate using a wire mesh with a pore size of 200 mesh. The ceramic substrate is made of alumina material with a purity of not less than 99%, and the average surface roughness of the ceramic substrate is not greater than Ra0.8. A vacuum defoaming machine is used to perform a 2-h vacuum defoaming treatment on the ceramic substrate coated with the sintered copper paste. The ceramic substrate coated with the sintered copper paste after the vacuum defoaming treatment is placed in a vacuum and heated to 80 °C and held for 20 min to obtain a sintered conductive copper paste coating and leveling assembly.

[0103] Step 4: Heat treatment for forming a copper conductive film

[0104] The sintered conductive copper paste coating and leveling assembly is placed in a protective atmosphere and heated at a heating rate of 2 °C / min to 700 °C and held for 5 h, and then heated at a heating rate of 5 °C / min to 900 °C and held for 2 h to obtain a copper conductive film material with a high shrinkage rate.

[0105] Example 6

[0106] Preparation of a copper conductive film with a high shrinkage rate:

[0107] Step 1: Preparation of a copper paste precursor material

[0108] An atomized copper powder and a reduced copper powder are mixed according to a ratio to prepare a conductive precursor material. The average particle size of the atomized copper powder is 3 - 5 μm, the average particle size of the reduced copper powder is 0.5 - 1 μm, and the conductive precursor material contains 70 wt.% of the atomized copper powder.

[0109] Terpineol, ethyl cellulose, polyvinylpyrrolidone K30, polyethylene glycol 200, paraffin, and polyoxypropylene are mixed in a weight ratio of 85:5:3:3:2:2 to obtain an organic mixed solution. The obtained organic mixed solution is stirred for 1 h under the condition of water bath heating at 80 °C to obtain an organic solution precursor material.

[0110] Mix bismuth oxide, neutral alumina, boric anhydride, and manganese dioxide in a ratio of 70:15:15:5 by weight to obtain an inorganic mixed powder. After roll-milling the obtained inorganic mixed powder for 12 h, heat it to 900 °C, hold for 1 h, and then air-cool. Under the condition of a ball-to-material ratio of 15:1, ball-mill the sintered inorganic mixed powder for 24 h, and screen the ball-milled material with a 200-mesh sieve to obtain an inorganic precursor material;

[0111] Step 2. Preparation of sintered conductive copper paste

[0112] Roll-mill and mix 72 parts by weight of the conductive precursor material and 10 parts by weight of the inorganic precursor material for 6 h. After mixing the obtained roll-milled mixture with 18 parts by weight of the organic solution precursor material, place it under magnetic stirring in a water bath heated to 60 °C for 2 h to obtain a sintered conductive copper paste;

[0113] Step 3. Coating and leveling treatment of the sintered conductive copper paste

[0114] Print the sintered copper paste on the surface of the ceramic substrate using a wire mesh with a pore size of 200 mesh. The ceramic substrate is made of alumina material with a purity of not less than 99%, and the average surface roughness of the ceramic substrate is not greater than Ra0.8. Use a vacuum degassing machine to perform a 2-h vacuum degassing treatment on the ceramic substrate coated with the sintered conductive copper paste. Place the ceramic substrate coated with the sintered conductive copper paste after vacuum degassing treatment in a vacuum and heat it to 80 °C and hold for 20 min to obtain a sintered conductive copper paste coating and leveling assembly;

[0115] Step 4. Forming heat treatment of the copper conductive film

[0116] Place the sintered conductive copper paste coating and leveling assembly in a protective atmosphere, heat it at a heating rate of 2 °C / min to 700 °C and hold for 5 h, and then heat it at a heating rate of 5 °C / min to 900 °C and hold for 2 h to obtain a high shrinkage rate copper conductive film material.

[0117] Example 7

[0118] Preparation of high shrinkage rate copper conductive film:

[0119] Step 1. Preparation of copper paste precursor material

[0120] Mix atomized copper powder and reduced copper powder according to the ratio to prepare a conductive precursor material. The average particle size of the atomized copper powder is 3 - 5 μm, the average particle size of the reduced copper powder is 0.5 - 1 μm, and the conductive precursor material contains 70 wt.% of atomized copper powder;

[0121] Mix terpineol, ethyl cellulose, polyvinylpyrrolidone K30, polyethylene glycol 200, paraffin wax, and polyoxypropylene in a ratio of 85:5:3:3:2:2 by weight to obtain an organic mixed solution. Stir the obtained organic mixed solution for 1 h under the condition of water bath heating at 80 °C to obtain an organic solution precursor material.

[0122] Mix bismuth oxide, neutral alumina, boric anhydride, and manganese dioxide in a ratio of 60:15:15:5 by weight to obtain an inorganic mixed powder. After roll milling the obtained inorganic mixed powder for 12 h, heat it to 1100 °C, keep it warm for 1 h, and then air cool it. Ball mill the sintered inorganic mixed powder for 24 h under the condition of a ball-to-material ratio of 15:1, and screen the material after ball milling with a 200-mesh sieve to obtain an inorganic precursor material.

[0123] Step 2. Preparation of sintered conductive copper paste

[0124] Roll mill and mix 72 parts by weight of the conductive precursor material and 10 parts by weight of the inorganic precursor material for 6 h. Mix the obtained roll milled and mixed material with 18 parts by weight of the organic solution precursor material, and then place it under the condition of water bath heating at 60 °C and magnetically stir for 2 h to obtain a sintered conductive copper paste.

[0125] Step 3. Coating and leveling treatment of the sintered conductive copper paste

[0126] Print the sintered copper paste on the surface of a ceramic substrate using a 200-mesh screen. The ceramic substrate is made of alumina material with a purity of not less than 99%, and the average surface roughness of the ceramic substrate is not greater than Ra0.8. Use a vacuum defoaming machine to perform a 2-h vacuum defoaming treatment on the ceramic substrate coated with the sintered conductive copper paste. Place the ceramic substrate coated with the sintered conductive copper paste after vacuum defoaming treatment in a vacuum and heat it to 80 °C and keep it warm for 20 min to obtain a sintered conductive copper paste coating and leveling assembly.

[0127] Step 4. Forming and heat treatment of the copper conductive film

[0128] Place the sintered conductive copper paste coating and leveling assembly in a protective atmosphere, heat it to 700 °C at a heating rate of 2 °C / min and keep it warm for 5 h, and then heat it to 900 °C at a heating rate of 5 °C / min and keep it warm for 2 h to obtain a copper conductive film material with a high shrinkage rate.

[0129] Example 8

[0130] Preparation of a copper conductive film with a high shrinkage rate:

[0131] Step 1. Preparation of copper paste precursor materials

[0132] Mix atomized copper powder and reduced copper powder according to the ratio to prepare a conductive precursor material. The average particle size of the atomized copper powder is 3 - 5 μm, and the average particle size of the reduced copper powder is 0.5 - 1 μm. The conductive precursor material contains 70 wt.% of atomized copper powder;

[0133] Mix terpineol, ethyl cellulose, polyvinylpyrrolidone K30, polyethylene glycol 200, paraffin, and polyoxypropylene according to a weight ratio of 85:5:3:3:2:2 to obtain an organic mixed solution. Stir the obtained organic mixed solution for 1 h under the condition of water bath heating at 80 °C to obtain an organic solution precursor material;

[0134] Mix bismuth oxide, neutral alumina, boric anhydride, and manganese dioxide according to a weight ratio of 55:15:15:5 to obtain an inorganic mixed powder. After roll-milling the obtained inorganic mixed powder for 12 h, heat it to 1200 °C, keep it warm for 1 h, and then air-cool it; Under the condition that the ball-to-material ratio is 15:1, ball-mill the sintered inorganic mixed powder for 24 h, and screen the material after ball-milling with a 200-mesh sieve to obtain an inorganic precursor material;

[0135] Step Two: Preparation of Sintered Conductive Copper Paste

[0136] Roll-mill and mix 72 parts by weight of the conductive precursor material and 10 parts by weight of the inorganic precursor material for 6 h. After mixing the obtained roll-milled mixture with 18 parts by weight of the organic solution precursor material, place it under the condition of water bath heating at 60 °C and stir magnetically for 2 h to obtain a sintered conductive copper paste;

[0137] Step Three: Coating and Leveling Treatment of Sintered Conductive Copper Paste

[0138] Print the sintered copper paste on the surface of the ceramic substrate using a wire mesh with a pore size of 200 mesh. The ceramic substrate is made of alumina material with a purity of not less than 99%, and the average surface roughness of the ceramic substrate is not greater than Ra0.8; Use a vacuum degassing machine to perform a 2-h vacuum degassing treatment on the ceramic substrate coated with the sintered copper paste. Place the ceramic substrate coated with the sintered copper paste after vacuum degassing in a vacuum and heat it to 80 °C and keep it warm for 20 min to obtain a sintered conductive copper paste coating and leveling assembly;

[0139] Step Four: Forming and Heat Treatment of Copper Conductive Film

[0140] Place the sintered conductive copper paste coating and leveling assembly in a protective atmosphere, heat it at a heating rate of 2 °C / min to 700 °C, then keep it warm for 5 h, and then heat it at a heating rate of 5 °C / min to 900 °C and keep it warm for 2 h to obtain a copper conductive film material with a high shrinkage rate.

[0141] Example 9 (Comparative Example)

[0142] Preparation of Copper Conductive Film:

[0143] Step 1. Preparation of Copper Paste Precursor Materials

[0144] Select atomized copper powder as the conductive precursor material, and the average particle size of the atomized copper powder is 3 - 5 μm;

[0145] Mix terpineol, ethyl cellulose, benzotriazole, polyacrylic acid, and polyoxypropylene in a weight ratio of 80:7:5:4:4 to obtain an organic mixed solution. Stir the obtained organic mixed solution for 1 h under the condition of water bath heating at 80°C to obtain an organic solution precursor material;

[0146] Mix bismuth oxide, neutral alumina, and calcium oxide in a weight ratio of 70:15:15 to obtain an inorganic mixed powder. After roll-milling the obtained inorganic mixed powder for 12 h, heat it to 900°C, keep it warm for 1 h, and then cool it in air; under the condition of a ball-to-material ratio of 15:1, ball-mill the sintered inorganic mixed powder for 24 h, and screen the ball-milled material with a 200-mesh sieve to obtain an inorganic precursor material;

[0147] Step 2. Preparation of Sintered Conductive Copper Paste

[0148] Roll-mill and mix 78 parts by weight of the conductive precursor material with 8 parts by weight of the inorganic precursor material for 6 h. After mixing the obtained roll-milled mixture with 14 parts by weight of the organic solution precursor material, place it under the condition of water bath heating at 60°C and magnetically stir for 2 h to obtain a sintered conductive copper paste;

[0149] Step 3. Coating and Levelling Treatment of Sintered Conductive Copper Paste

[0150] Print the sintered copper paste on the surface of the ceramic substrate using a 200-mesh screen. The ceramic substrate is made of alumina material with a purity of not less than 99%, and the average surface roughness of the ceramic substrate is not greater than Ra0.8; Use a vacuum degassing machine to perform a 2-h vacuum degassing treatment on the ceramic substrate coated with the sintered copper paste. Place the ceramic substrate coated with the sintered copper paste after vacuum degassing treatment in a vacuum and heat it to 80°C and keep it warm for 20 min to obtain a sintered conductive copper paste coating and levelling assembly;

[0151] Step 4. Forming Heat Treatment of Copper Conductive Film

[0152] Place the sintered conductive copper paste coating and levelling assembly in a protective atmosphere, heat it at a heating rate of 2°C / min to 700°C and then keep it warm for 2 h, and then heat it at a heating rate of 5°C / min to 750°C and keep it warm for 1 h to obtain a copper conductive film material.

[0153] Example 10

[0154] Figure 2 Macrographs of the high shrinkage rate copper conductive thin film materials prepared according to the method embodiments of the present invention and the copper conductive thin film materials prepared in the comparative example. Among them, Figure 2 (a), Figure 2 (b), Figure 2 (c), Figure 2 (d) and Figure 2 (e) are macrographs of the high shrinkage rate copper conductive thin film materials prepared in Example 1, Example 3, Example 4, Example 6 and Example 8 respectively, Figure 2 (f) is the macrograph of the copper conductive thin film material prepared in Example 9 (comparative example). As Figure 2 shown, it can be seen from the macrographs of the thin film materials prepared in the examples and the comparative example that after using the high heat flux reduced copper powder and the inorganic precursor and improving the organic precursor, shrinkage occurred during the sintering of the conductive copper paste. With the improvement of the internal components of the conductive copper paste and the adjustment of the sintering process, the shrinkage rate of the copper conductive thin film was further increased.

[0155] The SEM micrographs and EDS characterizations of the high shrinkage rate copper conductive thin film materials prepared in Examples 1-8 and the copper conductive thin film materials prepared in Example 9 (comparative example) were carried out using a Hitachi SU8020 cold field emission scanning electron microscope in Japan. The SEM micrographs of the high shrinkage rate copper conductive thin film materials prepared in Examples 1-8 and the copper conductive thin film materials prepared in Example 9 (comparative example) are shown in Figure 3 ; The EDS spectrum of the high shrinkage rate copper conductive thin film material prepared in Example 3 is shown in Figure 4 , the EDS spectrum of the high shrinkage rate copper conductive thin film material prepared in Example 4 is shown in Figure 5 , the EDS spectrum of the high shrinkage rate copper conductive thin film material prepared in Example 8 is shown in Figure 6 ;

[0156] Figure 3 are the SEM micrographs of the high shrinkage rate copper conductive thin film materials prepared in Examples 1-8 of the present invention and the copper conductive thin film materials prepared in Example 9 (comparative example); among them, Figure 3 (a), Figure 3 (b), Figure 3 (c), Figure 3 (d), Figure 3 (e), Figure 3 (f), Figure 3 (g), Figure 3 (h) are the SEM micrographs of the high shrinkage rate copper conductive thin film materials prepared in Examples 1 to 8 respectively, Figure 3 (i) is the SEM micrograph of the copper conductive thin film material prepared in Example 9 (comparative example). As Figure 3As shown, from the SEM micrographs of the high shrinkage rate copper conductive thin film materials prepared in Examples 1-8 and the copper conductive thin film material prepared in Example 9 (comparative example), it can be seen that after using the high heat flux reduced copper powder and inorganic precursors and improving the organic precursors, as the shrinkage rate of the copper conductive thin film gradually increases, the denseness and uniformity inside the thin film are also improved, the porosity gradually decreases, and the conductive paths become denser.

[0157] Figure 4 The EDS spectrum of the high shrinkage rate copper conductive thin film material prepared in Example 3 of the present invention, where Figure 4 (a) is the micrograph of the high shrinkage rate copper conductive thin film material prepared in Example 3, Figure 4 (b), Figure 4 (c) and Figure 4 (d) are the Cu element distribution, C element distribution and O element distribution maps of the high shrinkage rate copper conductive thin film material prepared in Example 3 respectively;

[0158] Figure 5 The EDS spectrum of the high shrinkage rate copper conductive thin film material prepared in Example 4 of the present invention; where Figure 5 (a) is the micrograph of the high shrinkage rate copper conductive thin film material prepared in Example 4, Figure 5 (b), Figure 5 (c) and Figure 5 (d) are the Cu element distribution, C element distribution and O element distribution maps of the high shrinkage rate copper conductive thin film material prepared in Example 4 respectively;

[0159] Figure 6 The EDS spectrum of the high shrinkage rate copper conductive thin film material prepared in Example 8 of the present invention; where Figure 6 (a) is the micrograph of the high shrinkage rate copper conductive thin film material prepared in Example 4, Figure 6 (b), Figure 6 (c) and Figure 6 (d) are the Cu element distribution, C element distribution and O element distribution maps of the high shrinkage rate copper conductive thin film material prepared in Example 8 respectively;

[0160] As Figure 4 、 Figure 5 and Figure 6 shown, from the EDS spectra of the high shrinkage rate copper conductive thin film materials prepared in Example 3, Example 4, and Example 8, it can be seen that after increasing the debinding temperature of the conductive copper paste and extending the debinding time, the organic precursors inside the copper conductive thin film decrease, indicating that the volatilization amount of the organic precursors during the debinding process increases, which is beneficial to reducing the resistivity of the copper conductive thin film.

[0161] Table 1 shows the performance parameters of the conductive copper pastes prepared in Exemplary Embodiments 1-8 and Embodiment 9 (comparative example) of the present invention. Among them, the debinding rate of the copper conductive film is the ratio of the sintering loss weight to the initial weight, and the weight is measured by an AS-FA3204 type high-precision electronic balance. The area shrinkage rate of the copper conductive film is the ratio of the residual area after sintering to the initial area before sintering, and the area is obtained by measuring the length with a vernier caliper and calculating using the area formula; the resistivity of the copper conductive film is obtained by the four-probe test method, and the measuring instrument is a CXT 2516 type resistivity meter, referring to the test standard "GB / T 17473.3-2022 Test Methods for Precious Metal Pastes for Microelectronic Technology - Part 3: Determination of Sheet Resistance", where mΩ / □ represents milliohm per square centimeter; the bonding strength of the copper conductive film is measured by a ZQ-21A type tensile testing machine, referring to the test standard GB / T 17473.4-2022 Test Methods for Precious Metal Pastes for Microelectronic Technology - Part 4: Determination of Adhesion.

[0162] It can be seen from Embodiments 1-8 and the comparative example that by introducing easily sintered reduced copper powder, preparing a new inorganic precursor with a high heat flux value, and improving the organic precursor and other comprehensive measures, the copper conductive film shrinks and the resistivity decreases. It can be seen from Embodiment 1, Embodiment 3, Embodiment 4, and Embodiment 8 that after increasing the proportion of the organic precursor and extending the debinding time, the debinding rate increases, which is beneficial to improving the shrinkage rate of the copper conductive film and further reducing the resistivity. It can be seen from Embodiment 4 and Embodiment 8 that by increasing the reduced copper powder in the conductive copper paste and reducing the mass fraction of bismuth oxide in the inorganic precursor, the sintering density of the conductive copper paste can be improved, the resistivity of the copper conductive film can be reduced, and the bonding strength between the film and the substrate can be increased.

[0163] Table 1

[0164]

[0165] The thermal properties of the atomized copper powder in Embodiments 1-8 and the comparative example of the present invention, the reduced copper powder in Embodiments 1-8, and the inorganic precursors in Embodiments 1-6 and the inorganic precursor in Embodiment 8 were respectively tested using a German STA 449F3 type synchronous thermal analyzer. The DSC curves of the atomized copper powder in Embodiments 1-8 and the comparative example are shown in Figure 7 ; the DSC curves of the reduced copper powder in Embodiments 1-8 are shown in Figure 8 ; the DSC curves of the inorganic precursors in Embodiments 1-6 are shown in Figure 9 , and the DSC curve of the inorganic precursor in Embodiment 8 is shown in Figure 10 .

[0166] According to Figure 7 the atomized copper powder in the indicated Embodiments 1-8 and the comparative example and Figure 8DSC curves of the reduced copper powder in Examples 1-8 shown. The heat flow of the reduced copper powder at the sintering temperature (700-900 °C) is significantly higher than that of the atomized copper powder. Combining with the performance of the high shrinkage rate copper conductive thin film materials in Examples 4 and 8, it can be seen that increasing the proportion of the reduced copper powder can effectively improve the adhesion between copper powders during sintering, improve the densification of the conductive copper paste, and thus reduce the resistivity.

[0167] According to Figure 9 the DSC curves of the inorganic precursors in Examples 1-6 shown and Figure 10 the DSC curve of the inorganic precursor in Example 8 shown. Combining with the high shrinkage rate copper conductive thin film materials in Examples 4 and 8, it can be seen that reducing the mass fraction of bismuth oxide in the inorganic precursor, the heat flow peaks of the inorganic precursor are more concentrated, and the heat flow during melting is enhanced, which helps to improve the uniformity and densification of the copper conductive thin film.

[0168] The preparation method of the high shrinkage rate copper conductive thin film of the present invention and the corresponding materials have the following beneficial technical effects:

[0169] 1. By preparing the conductive precursor material, the adhesion during sintering of the conductive copper paste is improved, and a higher shrinkage rate and lower resistivity are achieved after high-temperature sintering of the sintered conductive copper paste;

[0170] 2. By preparing the organic solution precursor material, the conductive copper paste shrinks under high-temperature sintering to form a denser conductive path, effectively reducing the resistivity and realizing the shrinkage of the sintered conductive copper paste at high temperature;

[0171] 3. By preparing the inorganic precursor material, the fluidity of the conductive paste during the curing process is improved, the internal densification of the conductive copper paste is higher, the resistivity is reduced, and the bonding strength between the copper paste and the substrate is improved.

[0172] The high shrinkage rate copper conductive thin film material prepared by the present invention has a high shrinkage rate, a uniform and flat surface, low resistivity and high bonding strength, and can meet the requirements of printed ceramic circuit boards (PCBs) and multilayer ceramic capacitors (MLCCs) for the conductivity and bonding strength of conductive pastes.

[0173] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A method for preparing a high shrinkage copper conductive film, characterized in that: The method comprises: Atomized copper powder and reduced copper powder are mixed according to a ratio to prepare a conductive precursor material, wherein the average particle size of the atomized copper powder is 3-5 μm, the average particle size of the reduced copper powder is 0.5-1 μm, and the conductive precursor material contains 70-90 wt.% of the atomized copper powder; Mix terpineol, ethyl cellulose, polyvinyl pyrrolidone K30, polyethylene glycol 200, paraffin wax, and polyoxypropylene according to a ratio to obtain an organic mixed solution, stir the obtained organic mixed solution under a water bath heating condition to obtain an organic solution precursor material, wherein the weight ratio of terpineol, ethyl cellulose, polyvinyl pyrrolidone K30, polyethylene glycol 200, paraffin wax, and polyoxypropylene is 85:5:3:3:2:2; Bismuth oxide, neutral aluminum oxide, boric anhydride, and manganese dioxide are mixed in a ratio to obtain an inorganic mixed powder, and the obtained inorganic mixed powder is sintered and then refined to obtain an inorganic precursor material, wherein the weight ratio of bismuth oxide, neutral aluminum oxide, boric anhydride, and manganese dioxide is 55-70:15:15:5; The conductive precursor material, the inorganic precursor material and the organic solution precursor material are mixed according to a proportion, and stirred evenly under a water bath heating condition to obtain a sintered conductive copper slurry; The sintered conductive copper paste is uniformly coated on the surface of the ceramic substrate, and the ceramic substrate coated with the sintered copper paste is subjected to vacuum defoaming treatment and vacuum leveling treatment in sequence to obtain a sintered conductive copper paste coated leveling component; The sintered conductive copper slurry coated leveling component is placed in a protective atmosphere for debinding heat treatment and curing heat treatment to obtain a high shrinkage copper conductive film material.

2. The method for preparing a high shrinkage copper conductive film according to claim 1, characterized in that: When the obtained organic mixed solution is stirred under the condition of water bath heating, the water bath heating temperature is 80° C. and the stirring time is 1 hour.

3. The method for preparing a high shrinkage copper conductive film according to claim 1, characterized in that: The sintering process includes: roller milling the obtained inorganic mixed powder for 12 hours, heating it to 900-1200° C., keeping it warm for 1 hour, and air cooling it.

4. The method for preparing a high shrinkage copper conductive film according to claim 1, characterized in that: The refinement treatment includes: ball milling the sintered inorganic mixed powder for 24 hours at a ball-to-material ratio of 15:1, and screening the ball-milled material with a 200-mesh screen to obtain an inorganic precursor material.

5. The method for preparing a high shrinkage copper conductive film according to claim 1, characterized in that: The conductive precursor material, the inorganic precursor material and the organic solution precursor material are mixed according to a proportion, and stirred evenly under water bath heating conditions to obtain a sintered conductive copper paste, including: 72-78 parts by weight of the conductive precursor material and 8-12 parts by weight of the inorganic precursor material are roller-milled for 6 hours, the roller-milled mixture obtained is mixed with 14-18 parts by weight of the organic solution precursor material, and then placed in a water bath heating condition of 60°C and magnetically stirred for 2 hours to obtain a sintered conductive copper paste.

6. The method for preparing a high shrinkage copper conductive film according to claim 1, characterized in that: The sintered conductive copper paste is uniformly coated on the surface of a ceramic substrate, including: using a screen with an aperture of 200 meshes to print the sintered copper paste on the surface of the ceramic substrate, the ceramic substrate is made of an aluminum oxide material with a purity of not less than 99%, and the average surface roughness of the ceramic substrate is not greater than Ra0.

8.

7. The method for preparing a high shrinkage copper conductive film according to claim 1, characterized in that: The ceramic substrate coated with the sintered copper paste is subjected to vacuum defoaming treatment and vacuum leveling treatment in sequence, including: using a vacuum defoaming machine to perform vacuum defoaming treatment on the ceramic substrate coated with the sintered copper paste for 2 hours, placing the ceramic substrate coated with the sintered copper paste that has undergone vacuum defoaming treatment in a vacuum and heating it to 80° C. for 20 minutes.

8. The method for preparing a high shrinkage copper conductive film according to claim 1, characterized in that: Placing the sintered conductive copper slurry coated leveling component in a protective atmosphere for debinding heat treatment and curing heat treatment to obtain a high shrinkage copper conductive film material includes: placing the sintered conductive copper slurry coated leveling component in a protective atmosphere, heating the temperature to 700°C at a heating rate of 2°C / min and then keeping the temperature for 2-5 hours, heating the temperature to 750-900°C at a heating rate of 5°C / min and then keeping the temperature for 1-2 hours to obtain a high shrinkage copper conductive film material.

9. A high shrinkage copper conductive film material, characterized in that: The high shrinkage copper conductive film material is prepared according to any one of claims 1-8.

Images