Tungsten copper electrode paste, method for preparing the same and metal electrode
By using the medium-temperature co-firing technology of tungsten copper composite powder and titanium diboride powder, the problems of high energy consumption in high-temperature sintering of HTCC and insufficient mechanical strength of LTCC have been solved, achieving a balance between high conductivity and mechanical strength, which is suitable for electronic packaging of high-frequency signal transmission and high-power devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NO 43 INST OF CHINA ELECTRONICS TECH GRP CETC
- Filing Date
- 2026-02-05
- Publication Date
- 2026-06-02
AI Technical Summary
The high-temperature sintering of existing HTCC technology results in high energy consumption and low conductivity of conductive materials, making it difficult to meet the requirements of high-frequency signal transmission. On the other hand, LTCC technology lacks mechanical strength, making it difficult to apply in high-power devices.
Tungsten-copper composite powder is used as the conductive phase, combined with titanium diboride powder, and densification is achieved through medium-temperature co-firing to improve conductivity. The printing performance and adhesion are improved by organic carrier and binder.
It achieves a balance between high conductivity and mechanical strength at medium temperatures, making it suitable for electronic packaging of high-frequency signal transmission and high-power devices.
Smart Images
Figure CN122127169A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electronic materials technology, and in particular to a tungsten-copper electrode paste, its preparation method, and a metal electrode. Background Technology
[0002] In the field of electronic packaging, high-temperature co-fired ceramic (HTCC) technology, with its superior mechanical strength, excellent thermal stability, and reliable chemical inertness, has been widely and maturely applied in aerospace, military electronics, and high-power power electronics applications where packaging reliability requirements are stringent. This technology involves simultaneously sintering ceramic green tape and metal paste at temperatures above 1500°C to form a dense, well-bonded packaging substrate, effectively protecting the internal chips from external environmental interference.
[0003] However, HTCC technology has gradually revealed two inherent challenges that are difficult to avoid in long-term applications: First, its sintering temperature is usually as high as 1500℃~1700℃. This extreme temperature condition not only leads to huge energy consumption in the production process, but also puts high demands on sintering equipment. Second, due to such a harsh high-temperature sintering environment, the conductive phase material can only be high-melting-point metals such as tungsten and molybdenum (melting points are all above 2600℃). However, the room temperature conductivity of these metals is only 20~30S / m (tungsten is 23S / m and molybdenum is 28S / m), which is far lower than that of excellent conductors such as silver (63S / m) and copper (59S / m). This directly leads to the problem of high inherent resistance and severe signal transmission attenuation in the final circuit. Especially in high-frequency signal transmission scenarios, the insertion loss increases significantly, making it difficult to meet the urgent needs of modern electronic devices such as 5G communication and high-performance computing for high-frequency transmission, high power density, low signal loss and miniaturized integration. To overcome the high-temperature bottleneck of HTCC technology, low-temperature co-fired ceramic (LTCC) technology emerged. This technology, by adding low-melting-point sintering aids such as borates and glass powders to the ceramic powder, successfully lowered the sintering temperature to a milder range of 850℃ to 900℃. This temperature condition allows the use of highly conductive metals such as silver (Ag) and gold (Au) as the conductive phase, thereby significantly reducing circuit resistance, improving signal transmission efficiency, and perfectly adapting to high-frequency, low-loss applications. However, LTCC technology also has significant drawbacks: due to the addition of a large amount of low-melting-point aids, its substrate material has a mechanical strength of approximately 150~200 MPa, typically significantly lower than that of HTCC materials (mechanical strength above 300 MPa), making it unsuitable for the complex environmental mechanical protection requirements of high-power devices. Therefore, the electronic packaging field urgently needs to develop a new type of electrode paste that can achieve highly conductive metal electrodes while ensuring the substrate has mechanical strength close to that of HTCC. This will achieve a better balance between different performance characteristics of packaged products, providing core technological support for the high-density, high-performance packaging of next-generation electronic devices. Summary of the Invention
[0004] Based on this, the purpose of the present invention is to provide a tungsten-copper electrode slurry, its preparation method and metal electrode, which can achieve dense co-firing in the medium temperature sintering temperature range (1200℃~1500℃) and obtain better conductivity than traditional HTCC tungsten or molybdenum electrodes.
[0005] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a tungsten-copper electrode paste, which is prepared from the following components in mass percentage: 65%~85% tungsten-copper composite powder, 12%~20% organic carrier, 0.5%~10.0% binder, 0.1%~2.0% titanium diboride powder, and 0~3.0% additives.
[0006] The tungsten-copper electrode slurry provided by this invention uses tungsten-copper composite powder as the conductive phase, replacing the pure tungsten or pure molybdenum used in traditional HTCCs. By introducing copper components, dense co-firing can be achieved at medium temperature (1200℃~1500℃), and superior conductivity can be obtained compared to traditional HTCC tungsten or molybdenum motors. At the same time, the introduction of titanium diboride powder suppresses the loss of copper elements during medium-temperature co-firing, thereby ensuring the conductivity of the conductive film layer.
[0007] As a further improvement to the above-mentioned solution of the present invention, the mass ratio of tungsten powder to copper powder in the tungsten-copper composite powder is 1~9:1; the tungsten-copper composite powder is a submicron-sized spherical or near-spherical powder with a D50 of 0.5~5.0 μm. The preparation method of the tungsten-copper composite powder involves placing the tungsten-copper composite powder, grinding fluid, and grinding media in a grinding container according to a certain formula ratio, performing a single grinding process, and using a laser particle size analyzer to test the particle size of the processed tungsten-copper composite powder. Then, by optimizing the grinding formula ratio and grinding time, the particle size of the tungsten-copper composite powder is controlled within the desired range (D50 of 0.5~5.0 μm). Preferably, the particle size of the tungsten-copper composite powder is 1 μm. Controlling the tungsten-copper ratio in the tungsten-copper composite powder can achieve an optimal balance between conductivity, strength / stability, and thermal expansion matching.
[0008] As a further improvement to the above-described scheme of the present invention, the organic carrier comprises a polymer and an organic solvent. The polymer is selected from at least one of nitrocellulose, ethylcellulose, and polyacrylic acid resin, and the organic solvent is selected from at least one of diethylene glycol butyl ether, xylene, terpineol, and propylene glycol methyl ether acetate. The organic carrier is prepared by placing the organic solvent in a mixing container and mixing thoroughly by mechanical stirring; weighing the polymer into the organic solvent and stirring thoroughly by mechanical stirring until a transparent solution or colloid without obvious insoluble substances is formed, which is the organic carrier. The concentration of the polymer in the organic carrier is 5wt%~50wt%; preferably 10wt%. The high polymer content of the organic carrier improves the printing performance of the electrode paste.
[0009] As a further improvement to the above-described solution of the present invention, the binder is selected from at least one of oxides and glasses. The oxide is selected from at least one of metal oxides and non-metal oxides, such as silicon dioxide, aluminum oxide, copper oxide, etc. The glass is a P-Zn-Sn-Al system glass, comprising the following components by mass percentage: P2O5 47wt%~72wt%, ZnO 16wt%~34wt%, SnO 7wt%~23wt%, Al2O3 5wt%~10wt%. The binder is prepared by: thoroughly mixing one or more oxides and / or glasses by mechanical stirring, and then grinding them to form a powder with a certain particle size distribution (0.5μm~15μm, preferably 1μm), thus obtaining the binder. The oxides and / or glasses enhance the bonding force between the metal electrode and the ceramic substrate, ensuring that the metal conductive film layer does not detach after co-firing.
[0010] As a further improvement to the above-described solution of the present invention, the preparation method of the titanium diboride powder is as follows: titanium diboride powder, grinding slurry, and grinding media are placed in a grinding container for grinding treatment, and the particle size of the treated titanium diboride powder is tested using a laser particle size analyzer to control the particle size of the titanium diboride powder within the required range. Preferably, the particle size of titanium diboride is 2 μm.
[0011] As a further improvement to the above-described solution of the present invention, the additive is selected from at least one of lecithin dispersants and polyester-type superdispersants. The printing performance of the electrode paste is optimized by the additive.
[0012] As a further improvement to the above-mentioned solution of the present invention, the sintering temperature of the tungsten copper electrode slurry is 1200℃~1500℃.
[0013] The present invention also provides a method for preparing the tungsten copper electrode slurry as described above, which includes the following steps: mixing tungsten copper composite powder, organic carrier, binder, titanium diboride powder and additives in proportion to form an initial slurry mixing system; and rolling the initial slurry mixing system to form the tungsten copper electrode slurry.
[0014] The present invention also provides a metal electrode prepared using the tungsten-copper electrode slurry as described above.
[0015] As a further improvement to the above-mentioned solution of the present invention, the preparation method includes the following steps: forming a circuit pattern with a line resolution ≥100μm on a green ceramic sheet by means of screen printing or additive manufacturing of the tungsten copper electrode paste, and then sintering to obtain a metal electrode.
[0016] As a further improvement to the above-mentioned solution of the present invention, the sintering atmosphere is argon or nitrogen, and the sintering temperature is 1200℃~1500℃.
[0017] Compared with the prior art, the present invention has the following beneficial effects: The tungsten-copper electrode paste proposed in this invention significantly improves conductivity by introducing copper, while maintaining thermal stability and strength using a tungsten framework, laying the material basis for achieving high conductivity at medium temperatures. At the same time, titanium diboride is introduced to achieve a copper loss prevention mechanism. Titanium diboride ensures that copper is effectively retained in the electrode through multiple mechanisms such as physically blocking diffusion paths and pinning grain boundaries to prevent copper oxidation. Attached Figure Description
[0018] Figure 1 This is a photograph of the tungsten-copper electrode paste prepared in Example 1 of the present invention. Figure 2 This is a schematic diagram of the multilayer ceramic substrate structure obtained in Embodiment 1 of the present invention. Detailed Implementation
[0019] To facilitate understanding of the present invention, a more comprehensive description will be given below with reference to specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention.
[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
[0021] Example 1 This embodiment proposes a tungsten-copper electrode paste, the preparation method of which includes the following five steps (1)-(5): (1) Preparation of metal powder: Weigh 100g of tungsten-copper composite powder (the mass ratio of tungsten powder to copper powder is 60:40), 200g of anhydrous ethanol, and 200g of grinding balls and add them to a ball mill jar. Process the powder at a ball milling speed of 400r / min for 1h, then filter and dry to obtain metal powder with a particle size of 1μm. (2) Adhesive preparation: Weigh 94g of phosphorus pentoxide, 60g of zinc oxide, 30g of stannous oxide, 16g of aluminum oxide, 200g of anhydrous ethanol and 200g of grinding balls and add them to a ball mill jar. Process the mixture at a ball milling speed of 100r / min for 1 hour, then filter and dry to obtain a glass mixture system. 150g of glass mixture was placed in a platinum crucible and melted at 1500℃, then quenched in water to make glass; 100g of glass, 150g of anhydrous ethanol and 100g of grinding balls were added to a ball mill jar and milled at 400r / min for 4h, then filtered and dried to obtain glass powder. Weigh 15g of alumina, 30g of silicon dioxide, 10g of copper oxide, 45g of the prepared glass powder, 200g of anhydrous ethanol and 100g of grinding balls and add them to a ball mill jar. Process the mixture at a ball milling speed of 400r / min for 2h, then filter and dry to obtain a powdery binder with a particle size of 1μm. (3) Titanium diboride powder treatment: Weigh 100g titanium diboride, 100g anhydrous ethanol and 100g grinding balls and add them to the ball mill jar. Process at a ball milling speed of 200r / min for 1h, then filter and dry to obtain titanium diboride powder with a particle size of 2μm. (4) Preparation of organic carrier: Weigh 100g of diethylene glycol butyl ether, 200g of terpineol and 100g of propylene glycol methyl ether acetate and place them in a beaker. Stir mechanically for 1h to obtain organic solvent. Weigh 8g of ethyl cellulose and 6g of nitrocellulose and add them to 86g of organic solvent. Heat and stir at 65℃ for 4h to fully dissolve and obtain organic carrier. (5) Preparation of tungsten-copper electrode slurry: Weigh 81g of metal powder, 14g of organic carrier, 3.5g of binder, 1g of titanium diboride powder and 0.5g of lecithin, and mechanically mix them at 1000r / min for 10min to obtain the initial tungsten-copper electrode slurry; place the initial tungsten-copper electrode slurry in a three-roll mill and roll it for 30min to obtain the tungsten-copper electrode slurry, as shown below. Figure 1 As shown.
[0022] The tungsten-copper electrode paste prepared in this embodiment was used to screen print circuit patterns onto a green ceramic sheet. The green ceramic sheet with the patterns was then dried, stacked, and pressed to obtain a sample to be fired. The sample was placed in an atmosphere sintering furnace, argon gas was introduced, and the temperature was increased from room temperature to 650°C at a rate of 2°C / min and held for 2 hours. Then, the temperature was increased to 1400°C at a rate of 2°C / min and held for 2 hours. It was then allowed to cool naturally to room temperature to obtain a multilayer metal electrode, such as... Figure 2 As shown. After testing, the sheet resistance of the multilayer metal electrode fabricated in this embodiment is 7.3 mΩ / .
[0023] Example 2 This embodiment proposes a tungsten-copper electrode paste, the preparation method of which includes the following five steps (1)-(5): (1) Preparation of metal powder: Weigh 100g of tungsten-copper composite powder (the mass ratio of tungsten powder to copper powder is 90:10), 100g of anhydrous ethanol and 100g of grinding balls and add them to a ball mill jar. Process the powder at a ball milling speed of 400r / min for 1h, then filter and dry to obtain metal powder with a particle size of 1μm. (2) Adhesive preparation: Weigh 130g of phosphorus pentoxide, 40g of zinc oxide, 24g of stannous oxide, 6g of aluminum oxide, 400g of anhydrous ethanol and 200g of grinding balls and add them to a ball mill jar. Process the mixture at a ball milling speed of 100r / min for 1 hour, then filter and dry to obtain a glass mixture system. 150g of glass mixture was placed in a platinum crucible and melted at 1400℃, then quenched in water to make glass; 100g of glass, 200g of anhydrous ethanol and 100g of grinding balls were added to a ball mill jar and processed at a ball milling speed of 400r / min for 2h, then filtered and dried to obtain glass powder. Weigh 25g of alumina, 35g of silica, 40g of glass powder, 200g of anhydrous ethanol and 100g of grinding balls and add them to a ball mill jar. Process the mixture at a ball milling speed of 400r / min for 2 hours, then filter and dry to obtain a powdery binder with a particle size of 1μm. (3) Titanium diboride powder treatment: Weigh 100g titanium diboride, 200g anhydrous ethanol and 100g grinding balls and add them to the ball mill jar. Process at a ball milling speed of 200r / min for 2h, then filter and dry to obtain titanium diboride powder with a particle size of 2μm. (4) Preparation of organic carrier: Weigh 100g xylene and 200g terpineol and place them in a beaker. Stir mechanically for 1h to obtain organic solvent. Weigh 5g ethyl cellulose and 5g polyacrylic acid resin and add them to 90g organic solvent. Heat and stir at 65℃ for 4h to fully dissolve and obtain organic carrier. (5) Preparation of tungsten copper electrode slurry: Weigh 80g of metal powder, 16g of organic carrier, 2g of binder, 1.5g of titanium diboride powder and 0.5g of polyester superdispersant, and mechanically mix them at a speed of 1000r / min for 10min to obtain the initial tungsten copper electrode slurry; place the initial tungsten copper electrode slurry in a three-roll mill and roll it for 30min to obtain the tungsten copper electrode slurry.
[0024] The tungsten-copper electrode paste prepared in this embodiment was used to screen print circuit patterns onto a green ceramic sheet. The patterned green ceramic sheet was then dried, stacked, and pressed to obtain a sample for firing. The sample was placed in an atmosphere sintering furnace, nitrogen gas was introduced, and the temperature was increased from room temperature to 550°C at a rate of 2°C / min, held for 2 hours, and then increased to 1300°C at a rate of 2°C / min, held for 2 hours. It was then allowed to cool naturally to room temperature to obtain a multilayer metal electrode. Testing showed that the sheet resistance of the multilayer metal electrode prepared in this embodiment was 8.7 mΩ / min. .
[0025] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0026] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.
Claims
1. A tungsten-copper electrode paste, characterized in that, It is prepared from the following components by mass percentage: 65%~85% tungsten-copper composite powder, 12%~20% organic carrier, 0.5%~10.0% binder, 0.1%~2.0% titanium diboride powder, and 0~3.0% additives.
2. The tungsten-copper electrode paste according to claim 1, characterized in that, In the tungsten-copper composite powder, the mass ratio of tungsten powder to copper powder is 1~9:1; the tungsten-copper composite powder is a submicron-sized spherical or near-spherical powder with a D50 of 0.5~5.0μm.
3. The tungsten-copper electrode paste according to claim 1, characterized in that, The organic carrier comprises a polymer and an organic solvent, wherein the polymer is selected from at least one of nitrocellulose, ethylcellulose and polyacrylic acid resin, and the organic solvent is selected from at least one of diethylene glycol butyl ether, xylene, terpineol and propylene glycol methyl ether acetate.
4. The tungsten-copper electrode paste according to claim 1, characterized in that, The binder is selected from at least one of oxides and glass; the oxide is selected from at least one of metal oxides and non-metal oxides; the glass is a P-Zn-Sn-Al system glass, and the glass contains the following components by mass percentage: P2O5 47wt%~72 wt%, ZnO 16wt%~34wt%, SnO 7wt%~23wt%, Al2O3 5wt%~10 wt%.
5. The tungsten-copper electrode paste according to claim 1, characterized in that, The additive is selected from at least one of lecithin dispersants and polyester-type superdispersants.
6. The tungsten-copper electrode paste according to claim 1, characterized in that, The sintering temperature of the tungsten copper electrode slurry is 1200℃~1500℃.
7. A method for preparing a tungsten-copper electrode paste as described in any one of claims 1-6, characterized in that, It includes the following steps: Tungsten-copper composite powder, organic carrier, binder, titanium diboride powder, and additives are mixed evenly in proportion to form an initial slurry mixing system; the initial slurry mixing system is then rolled to form a tungsten-copper electrode slurry.
8. A metal electrode, characterized in that, It is prepared using the tungsten-copper electrode paste as described in any one of claims 1-6.
9. The metal electrode according to claim 8, characterized in that, The preparation method includes the following steps: forming a circuit pattern on a green ceramic sheet by screen printing or additive manufacturing of the tungsten copper electrode paste, and then sintering to obtain a metal electrode.
10. The metal electrode according to claim 9, characterized in that, The sintering atmosphere is argon or nitrogen, and the sintering temperature is 1200℃~1500℃.