TW202213391A - Conducting wire with high conductivity, alloy and manufacturing method of new-shape terminal electrode for converting the thick-film aluminum electrode into a thick-film metal or alloy electrode with high conductivity by chemical redox conversion - Google Patents

Abstract

Disclosed are a conducting wire with high conductivity, an alloy and a manufacturing method of a new-shape terminal electrode, in which two innovating material methods are provided for improving the conductivity of a thick-film aluminum electrode to be equal to or approximately equal to the conductivity of a thick-film printed silver electrode or a copper electrode sintered at a reducing atmosphere, and a new-shape terminal electrode of a laminated ceramic component is manufactured by using such a novel material. The material is manufactured by the steps of: converting the thick-film aluminum electrode into a thick-film metal or alloy electrode with high conductivity by chemical redox conversion; chemically or physically coating the surface of a metal aluminum particle with a thin film to form a core-shell structure, performing sintering to raise the temperature for generating a film-coated metal and aluminum alloy, and liquefying the alloy to connect closest stacked aluminum particles so as to achieve a thick-film printed aluminum electrode with ultra high conductivity. The innovative electrode shape enables such a technology to be applicable to the terminal electrode of the laminated ceramic component, and a five-side terminal electrode manufactured by immersion plating and high-temperature sintering is changed into a low-temperature two/three-side terminal electrode manufactured by printing and wet electroplating or chemical deposition.

Description

High-conductivity wire, alloy and new-shaped terminal electrode fabrication method

The invention relates to a high-conductivity wire, an alloy and a new-shaped laminated ceramic The invention relates to a method for making a terminal electrode of a ceramic element, especially to a high-conductivity wire and an alloy that can improve the conductivity of a thick-film aluminum electrode that is equal to or close to that of a thick-film printed silver electrode or a copper electrode sintered in a reducing atmosphere, In particular, it refers to a thick-film aluminum electrode (including replacement metal) that uses chemical redox substitution to replace a thick-film copper electrode with high conductivity or other metals such as nickel and alloys; the other refers to thick-film printed aluminum (including replacement metal). ) Electrode sintering does not require further chemical replacement treatment, that is, high-conductivity wires or other metals such as nickel and alloys can be obtained with the conductivity of sintered printed silver electrodes under air or sintered copper electrodes under reducing atmosphere. The application of the new shape of the innovative electrode changes the current passive element multilayer ceramic element using immersion plating and high-temperature sintering to the low-temperature two- to three-side terminal electrode produced by printing and wet electroplating or electroless plating.

At present, the mainstream material of metallization technology is thick-film printed silver electrodes. It can be sintered in air, but metallic silver is a precious metal, and the material cost is expensive. Another alternative material is thick-film printed copper electrodes. Although it is a low-cost copper material, metal copper is easily oxidized when sintered at high temperatures. Therefore, oxidation of copper electrodes must be avoided under a reducing atmosphere such as nitrogen protection, resulting in expensive manufacturing process. In addition, when the ultra-low temperature sintering is less than 200°C, nano-silver powder must be used to make nano-silver paste to obtain dense and high-conductivity silver electrodes. However, the price of nano-silver powder is very expensive, almost ten times the price of current silver powder. Therefore, thick-film printing silver paste or nano-silver paste is a precious metal material, and the cost is very high. On the other hand, in the past, these base metal conductive thick film or alloy thick film printing conductive pastes required high temperature and special reducing atmosphere. For example, the thick-film printing copper paste must be sintered in a nitrogen atmosphere to prevent oxidation, resulting in an expensive manufacturing process.

Thick-film printed aluminum electrodes can be sintered in air with low process costs, and the raw materials are not Very cheap, the only biggest disadvantage is that there will be a very thin aluminum oxide film on the surface of the thick film metal aluminum powder particles, which causes the metal aluminum powder of the thick film printed aluminum electrode to be unable to shrink during sintering to achieve the purpose of densification and the existence of the aluminum oxide layer. Block the contact of metal aluminum particles, so the conductivity of thick film aluminum electrode is much lower than that of general thick film silver electrode or copper electrode, and its conductivity is only silver electrode sintered under thick film printing air or copper sintered under reducing atmosphere 1/500 to 1/1000 of the electrode, currently only solar cells are used as a reflective and large-area back electrode in the thick film conductor market.

In addition, for the electrode shape, please refer to Table 1. There are currently two main techniques for making terminal electrodes for passive components. The first is the pentagonal terminal electrode technology. 1 is stacked in the ceramic body 2, and the two ends are terminal electrodes 3. The main process is shown in Figure 18. It is integrally formed by immersion plating process, and then undergoes high temperature heat treatment. If it is copper or nickel conductive paste, it needs to be in a reducing atmosphere. The heat treatment process that must avoid oxidation; the second is the three-sided electrode technology, its structure is shown in Figure 17 (b), the main process is to use screen printing to make the front end electrode 4, the back end electrode 5 and the sintering. Then, the side terminal electrodes 6 are formed by sputtering. In terms of the appearance of the formed terminal electrode, the first type of terminal electrode integrally formed by immersion plating is likely to have a moon edge shape, as shown in Figure 19 (a), where the arrow points to the moon edge shape; Two kinds of three-sided terminal electrodes formed by printing and sputtering have a square shape without a moon edge, as shown in Figure 19(b), where the arrow points indicate that the terminal electrode has a square shape without a moon edge. Table I Pentagonal electrode technology Trilateral terminal electrode technology shape and process 1. Pentagonal terminal electrode 2. Dip plating + sintering 1. Trilateral terminal electrode 2. Printing + sintering + sputtering application Multilayer Ceramic Capacitors Chip resistors Schematic As shown in Figure 17(a) As shown in Figure 17(b) actual sample As shown in Figure 19(a) As shown in Figure 19(b) feature 1. The terminal electrode shape has a moon edge 2. The dip-plated terminal electrode is integrally formed (five sides) 1. The shape of the terminal electrode is square and no moon side. 2. The terminal electrode is formed twice by printing the front and back electrodes (two sides) and the sputtering side electrode (one side).

At present, the technology of multilayer ceramic capacitors often utilizes thin dielectric layers and high multi-layer internal electrodes. The capacitance value develops in the direction. Because the multi-layer ceramic and the inner electrode are shared, the internal stress is easily generated due to the mismatch between the shrinkage of the metal electrode and the ceramic green embryo. When the terminal electrode is sintered at high temperature, the internal stress is easy to release energy and cause component cracks. Therefore, the lower the sintering temperature of the terminal electrode, the better is the current research and development trend. In addition, the size of the components of the multilayer ceramic capacitor is getting smaller and smaller, the production of the terminal electrode also needs to be more and more precise, and the shape and square requirements are also becoming more and more important. high.

In view of the above-mentioned problems of the prior art, in order to solve them both, a This can improve the conductivity of thick film printed aluminum electrodes to be comparable to or close to that of silver electrodes sintered in thick film printing air or copper electrodes sintered in reducing atmosphere, and can be further combined with new material innovation, using chip-like The invention of the three-side terminal electrode technology of the resistor to make the multilayer ceramic capacitor is really necessary.

The main purpose of the present invention is to overcome the above-mentioned problems encountered in the prior art, And provide a high-conductivity wire, alloy and new shape terminal electrode manufacturing method, and propose two innovative methods The conductivity of thick-film aluminum electrodes can be improved to be comparable or close to those of thick-film printed silver electrodes or copper electrodes sintered in a reducing atmosphere.

Another object of the present invention is to provide a high-conductivity wire, an alloy and a new With the method for making the shaped end electrode, the sintering of the thick-film printed aluminum electrode does not require further chemical replacement treatment, so that the conductivity can be comparable to that of the printed silver electrode sintered in air or the sintered copper electrode in a reducing atmosphere.

In order to achieve the above purpose, the present invention is a high-conductivity wire, an alloy and a new shape The method for making terminal electrodes is to coat a thin metal film on the surface of several metal aluminum particles by chemical or physical means to form a core aluminum shell metal structure, and use sintering and heating to make the shell metal and the outside of the core aluminum form an aluminum shell The metal alloy is heated to a sintering temperature of 300-660°C exceeding the melting point of the aluminum shell metal alloy, and the aluminum shell metal alloy is liquefied to connect the most densely packed metal aluminum particles around without further chemical replacement treatment. A high-conductivity thick-film aluminum paste for high-conductivity thick-film aluminum electrodes is produced.

In the above-mentioned embodiment of the present invention, the metal film of the coating is a silver metal film, and the metal alloy of the aluminum shell is an aluminum-silver alloy (Ag ₂ Al).

In the above embodiments of the present invention, the metal aluminum particles are 5 μm in size and particle size Arranged in the most densely packed form with 2 μm.

In the above embodiments of the present invention, the high-conductivity thick-film aluminum paste can be printed on various disks Surface electrodes of shaped and bulk ceramic components, such as safety capacitors, GPS antennas, thermistors (NTC, PTC), varistors or all components that can be used as electrodes on the surface.

In the above-mentioned embodiments of the present invention, the high-conductivity thick-film aluminum electrode is suitable for Porcelain components, metal plates, glass substrates, or co-fired internal electrodes with low-temperature ceramic green embryos.

Another object of the present invention is to provide an integrated thick film printing and electroplating deposition technology, using thick film printing and sintering under air, and then using metal redox deposition technology to make base A method for making high-conductivity wires, alloys and new-shaped terminal electrodes of metal conductive thick film or alloy thick film.

In order to achieve the above purpose, the present invention is a high-conductivity wire, an alloy and a new shape The method of making the terminal electrode is to use a thick film to print a thick film aluminum layer with a high oxidation potential (including a replacement metal), and then place it in a metal solution with a low oxidation potential, and control the solution temperature and immersion time for chemical oxidation. The reduction-replacement reaction results in a thick-film metal layer with a low oxidation potential.

In the above embodiments of the present invention, the metal solution can be copper sulfate, nickel sulfate, sulfur Manganese acid, chromium sulfate, silicon compounds or combinations thereof.

In the above embodiments of the present invention, the thick-film metal layer may be a thick-film copper layer, a thick-film nickel layer layer, thick-film copper-nickel alloy layer, thick-film copper-manganese-nickel alloy layer, or thick-film nickel-chromium-silicon alloy layer.

In the above-mentioned embodiments of the present invention, the thick film metal layer is sintered under air to form a High conductivity copper electrode or copper die-bonding electrode.

In the above-mentioned embodiment of the present invention, the copper electrode can be applied to be fabricated from low temperature heat treatment To high temperature sintered plastic flexible boards, glass substrates, solar silicon substrates and ceramic substrates, as well as new shape terminal electrodes for the production of innovative multilayer ceramic capacitors, where the processing temperature of the plastic flexible board is a low temperature of 70-200°C, and the processing temperature of the glass substrate is It is a medium temperature of 500-600°C, the processing temperature of the solar silicon substrate is a medium temperature of 500-600°C, and the processing temperature of the ceramic substrate is a high temperature of 850-1000°C.

In the above-mentioned embodiments of the present invention, the terminal electrodes of the multilayer ceramic capacitor with a new shape are The copper or nickel side end electrodes of the multilayer ceramic capacitor are made by copper or nickel substitution plating. New shape terminal electrode.

In the above-mentioned embodiment of the present invention, the side terminal electrode of the multilayer ceramic capacitor can be further Fabrication of copper or nickel sides of MLCCs by general (conventional) electroless plating, electroplating and sputtering electrode.

Please refer to "Fig. 1 to Fig. 16C", which are schematic diagrams of the redox reaction of copper particles replacing aluminum particles and copper thick film replacing aluminum thick film, the present invention using the redox reaction of metal to replace the schematic diagram, The high-conductivity copper electrode of the present invention is applied to the front and back sides of various substrates. The present invention utilizes large and small coated metal aluminum particles to achieve the most densely packed arrangement of thick-film aluminum electrodes. The multilayer ceramic capacitor of the present invention 2～ A schematic diagram of the comparison of the structure of the three-side terminal electrode and the conventional MLCC five-sided terminal electrode, the schematic diagram of the increase of the inner electrode density on the side of the two-to-three-sided terminal electrode of the multilayer ceramic capacitor of the present invention, the two-to-three-sided terminal of the MLCC of the present invention The schematic diagram of increasing the density of the inner electrode on the side of the electrode, the schematic diagram of increasing the density of the inner electrode on the side of the low-temperature ceramic co-fired LTCC filter of the present invention, the schematic diagram of increasing the density of the inner electrode on the side of the low-temperature ceramic co-fired LTCC filter, the present invention converts the back aluminum electrode of the double-sided solar energy into a high-conductivity copper electrode The schematic diagram of the present invention, the back aluminum electrode of the double-sided solar energy of the present invention is converted into a high-conductivity copper electrode, and the photoelectric conversion efficiency of the solar cell is improved. The schematic diagram of the manufacturing process of the two to three side terminal electrodes of the multilayer ceramic capacitor of the present invention, the present invention uses low-temperature aluminum paste to make the terminal electrodes of the multilayer ceramic element, and then replaces it with copper sulfate. The schematic diagram of the electroplating (electroless plating) of the side electrode, the result of the structure of the nickel side electrode of the multilayer ceramic capacitor of the present invention by using the dense nickel inner electrode on the side by wet chemical treatment, the two to three side ends of the multilayer ceramic capacitor of the present invention Electrode results diagram, schematic diagram of the conductivity of the thick film printing silver-coated aluminum metal paste of the present invention sintered at different temperatures, XRD patterns of Ag ₂ Al generated by the present invention as the sintering temperature increases, and silver-coated aluminum metal paste of the present invention at different temperatures SEM image of the sintered microstructure. As shown in the figure: the present invention is a method for making high-conductivity wires, alloys and new-shaped terminal electrodes. The high-conductivity wires and alloys can be applied to flexible board RFID antennas, PCB packaging solid crystals, solar cells, and ceramic components terminal electrodes. , LED heat dissipation substrate and glass substrate, two innovative methods are proposed to improve the conductivity of thick-film aluminum electrodes and thick-film printed silver electrodes or copper electrodes sintered in a reducing atmosphere.

The first innovative approach involves chemical substitution of thick-film aluminum electrodes (containing substitutional metals) into high-conductivity Electricity thick film copper electrodes. This innovative method integrates thick film printing and electroplating deposition technology, uses thick film printing and sintering under air, and then uses metal redox deposition technology to produce base metal conductive thick film or alloy thick film.

The principle of this innovative method is to use the redox reaction of the metal to replace, such as the first 1 and 2 as shown in Fig. In Figure 1(a), a single metal aluminum particle 11 with a high oxidation potential can be immersed in a metal solution 12 with a low oxidation potential for redox replacement reaction. In this embodiment, the aluminum particle 11 is replaced by a copper particle 13 . Similarly, in Figure 1(b), if a layer of thick-film aluminum layer 21 (containing the replacement metal) with a high oxidation potential printed after sintering is immersed in a metal solution 22 with a low oxidation potential, it can also be immersed for a period of time. The redox substitution reaction is performed to form a thick-film metal layer with a low oxidation potential. In this embodiment, the thick-film aluminum layer 21 is replaced with a thick-film copper layer 23 .

Because aluminum metal powder is quite cheap and has high oxidation potential, it is surface pretreated with hydrofluoric acid. It can then be used as a sacrificial layer. As shown in Fig. 2, the thick film metal aluminum layer 21 has a high oxidation potential, and many low oxidation potential metal solutions 22 such as copper sulfate, nickel sulfate, manganese sulfate, chromium sulfate, and silicon compounds can be used to replace the thick film The aluminum layer 21 becomes a thick-film copper layer 23 or a thick-film nickel layer 24, or even a thick-film copper-nickel alloy layer 25 or a copper-manganese-nickel, nickel-chromium-silicon alloy layer.

As shown in Figure 3, the innovative method is used on various substrates, as shown in the figure by From left to right are high-conductivity copper wires made of ceramics, PET film (thick sheet), PET film (thin sheet), glass substrate and aluminum alloy casing that do not need to be sintered in a reducing atmosphere. The upper row is the substrate. The front side, the bottom row is the back side of the substrate.

The second innovative method is high conductivity thick film aluminum electrodes pretreated with aluminum powder. in order to change To improve the conductivity of thick film aluminum electrodes, this innovative method is based on several metal aluminum particles of different sizes31 The surface is coated with a thin metal film 32 by chemical or physical methods to form a core (aluminum) shell (metal) structure, and the shell metal and the outside of the core aluminum form an aluminum shell metal alloy 33 by heating up by sintering. When the sintering temperature exceeds the melting point of the aluminum shell metal alloy at 300-660°C, the aluminum shell metal alloy is liquefied to connect the most densely packed metal aluminum particles 31 around to improve the conductivity of the overall thick-film aluminum electrode. As shown in Figure 4, in order to achieve the highest conductivity of the thick-film aluminum electrode, the most densely packed arrangement of the thick-film aluminum electrode is achieved by using metal aluminum particles 31 in the form of a large particle size of 5 μm and a small particle size of 2 μm. First, the front-coated metal film 32 is used to form an alloy of metal-film aluminum and liquefy and connect each metal aluminum powder to achieve a thick-film aluminum electrode with the same conductivity as the current mainstream thick-film silver electrode or copper electrode.

The present invention utilizes the above-mentioned innovative high-conductivity material to make an innovative multilayer ceramic element The application of the new shape of the terminal electrode changes the shape of the current pentagonal terminal electrode using immersion plating and high temperature sintering into a triangular terminal electrode using printing and electroplating or electroless plating.

The comparison results of the innovative multilayer ceramic capacitor (MLCC) terminal electrode technology of the present invention and the currently known MLCC terminal electrode technology in terms of structure, process, materials and characteristics are shown in Table 2 and Figure 5. Figure 5(a) is the second-to-three-side terminal electrode of the multilayer ceramic capacitor produced by the innovative multilayer ceramic capacitor terminal electrode (chip resistor-like terminal electrode) technology of the present invention, and Figure 5(b) is currently known. The terminal electrode of the multilayer ceramic capacitor is made by the terminal electrode technology of the multilayer ceramic capacitor. Table 2 shows that this innovative technology changes the shape of the terminal electrodes on the five sides of the current multilayer ceramic capacitor to the shape of the terminal electrodes on the three sides of the current chip resistor. Follow the change. Table II Current MLCC terminal electrodes The present invention innovates MLCC terminal electrodes (chip resistor-like terminal electrodes) Schematic As shown in Figure 5(a) As shown in Figure 5(b) structure pentagonal electrode Trilateral electrode Process Immersion plating integrated molding + high temperature heat treatment in reducing atmosphere Screen printing front and back electrodes (co-fired) + electroplating, electroless plating, sputtering Material Thick Film Copper Conductive Paste Copper and nickel solution feature 1. The printing shape of the terminal electrode is better than the immersion plating shape, especially for small-sized components. 2. Low temperature process (<100°C) 3. The current MLCC immersion plating process and copper sintering process are omitted. 4. The use of copper and nickel solutions has low material cost

From the above comparison, it can be seen that the process is changed from the original immersion plating integrated forming and sintering heat treatment. The front and back electrodes are printed and co-fired with the ceramic green body, and then the third side electrodes are made by low temperature electroplating, electroless plating or sputtering process.

This multilayer ceramic capacitor innovative two-to-three-side terminal electrode technology and the current five-side terminal electrode technology There are at least four advantages to the extreme technology comparison: 1. The printing process replaces the immersion plating process to make the terminal electrode shape square without a moon edge, which can improve the quality of the terminal electrode shape, especially for small-sized MLCCs. 2. The ultra-low temperature process is less than 100°C, which improves and reduces the internal stress caused by the heat treatment of the terminal electrode in a high-temperature reducing atmosphere. The quality problem, and the innovative high-density and thin layer of the terminal electrode can improve the current use of glass-containing copper paste for high-temperature dipping. Quality problems of sintered copper terminal electrodes. 3. The current immersion plating process of multilayer ceramic capacitors and the process of high-temperature sintering of terminal electrodes in a reducing atmosphere are omitted, which greatly reduces the process cost. 4. It is not necessary to use thick-film copper conductive paste, and it can be changed to copper or nickel chemical solution, which greatly reduces the material cost.

In addition, the novel two- to three-sided terminal electrodes can be applied to laminated ceramic components, such as Multilayer ceramic capacitors (as shown in Fig. 6(a), Fig. 6(b)), multilayer ceramic inductors (as shown in Fig. 7(a), Fig. 7(b)) and low temperature ceramic co-fired LTCC Filters (as shown in Figure 8(a), Figure 8(b)), etc., can be printed on both ends of the component to make side electrodes of two to three side electrodes when the inner layer electrodes are screen-printed. Seed electrodes, increase the electrode density of the side electrodes (as shown in Figure 6(b), Figure 7(b) and Figure 8(b)), in order to facilitate the use of electroplating or electroless plating in the subsequent process to make two ~ The side electrodes of the trilateral end electrodes. Among them, in Fig. 7(a), a1 is a coil, a2 is an external electrode, and a3 is a non-magnetic ceramic.

The following examples are only examples for understanding the details and connotations of the present invention, but are not intended to limit formulate the scope of the patent application of the present invention.

[Embodiment 1: Solar Cell] Figure 9A shows the back aluminum electrode of the solar electrode. Through the innovative process proposed by the present invention, the original back aluminum electrode of the double-sided solar energy can be converted into a high-conductivity copper electrode. Due to the increase of the electrode conductivity, the photoelectric conversion efficiency of the solar cell is improved. It is also improved, as shown in Fig. 9B, the optimal state of the bifacial solar module and the data of the front and rear surfaces in this state. In the same production method, the current positive silver electrode of the solar cell can be reprinted into a high-conductivity positive-aluminum electrode, and then the positive-aluminum electrode can be immersed in a copper sulfate solution to convert it into a high-conductivity positive copper electrode. The innovative air-sintered positive copper electrode of the present invention replaces the current solar positive silver electrode.

[Embodiment 2: Encapsulation and bonding] At present, tin-lead is used as the main material for the bonding adhesive. In addition to the environmental protection issue, the insufficient thermal conductivity when applied to high-power bonding is also another issue. Rice silver is used to replace the current tin-lead solid crystal paste. However, nano-silver is quite expensive to use as solid crystal paste. The innovative process of the present invention sinters high-conductivity solid crystal copper at low temperature and replaces aluminum paste (containing copper sulfate crystals) to become low temperature. Compared with the nano-bonded silver paste b2 (Heraeus) currently on the market, copper-bonded b1 can produce very low-cost copper electrodes, and in terms of characteristics, Figure 10 (a) and Table 3 can illustrate this innovation. The test results of the characteristics (such as adhesion, thermal conductivity and electrical conductivity) of the low-temperature copper bonding during the process are comparable to the current nano-silver bonding. Figure 10(b) is the low-temperature copper described in Figure 10(a). The microstructure of solid crystal (copper replaced aluminum), where c1 is a diode, c2 is copper replaced aluminum, and c3 is a gold-plated substrate. Table 4 shows that the adhesion of the low-temperature copper solid crystal (copper substituted aluminum) of the present invention is comparable to that of the current nano-silver solid crystal (Heraeus). Table 3 project Heraeus (ASP 295-79P2) Alpha (ATROX_800HT2V) Kyocera (XT2773R7) this invention silver content 86±1% none 91.1% 80% Silver glue thickness ~20μm 18~20μm 18~22μm 20μm Sintering maximum temperature 230°C (60min) under air, nitrogen 200°C (120min) under air 200°C (90min) under air 250°C (90min) under nitrogen <200°C under air Applicable attachment Pt/Au/Ag Au/Ag/Cu Au/Ag/Cu Au/Ag/Cu modulus 15~40 Gpa(25°C) 9.1 Gpa (25°C) 1.9 Gpa (260°C) 26.2 Gpa(25°C) 18.3 Gpa(260°C) 15~40 Gpa(25°C) conductivity 1x10 ^-6 (Ω*m) 2x10 ^-6 (Ω*m) 4.1x10 ^-6 (Ω*m) 5x10 ^-7 (Ω*m) thermal conductivity 100~170W/mk 140W/mk 200W/mk 200W/mk cost 3.6 USD/g(10kg) 4.7~4.9 USD/g(4kg) 7.7 USD/g(1kg) 5.1 USD/g(10kg) 0.008~0.01 USD/g Table 4 Adhesion (kgf) Adhesion (Mpa) Silver Paste (85%) - Heraeus 7.5 15.9 The Invention - Copper Replaces Aluminum 7.8 16.8

[Embodiment 3: RFID Antenna] Generally, a radio frequency identification (RFID) antenna is currently made by sticking an aluminum foil or copper foil of about 10 μm on a polyethylene terephthalate (PET) film. The RFID antenna is fabricated by the subtractive process of complex printing, baking, exposure, development and etching; another method is the innovative process and material of the present invention, printing thick-film aluminum paste (containing copper sulfate crystals), baking and then chemically Replacement in the copper sulfate solution after 30 minutes to become a high-conductivity RFID copper antenna (in which the immersion time is controlled to form 0 min of aluminum; 5 min of slight copper; 10 min of partial copper; 20 min of chemical replacement of copper), this process is addition. The process reduces material waste, the process equipment is simple, and the return loss of the antenna characteristic is -24.248 dB better than the -14.707 dB of the etched RFID aluminum antenna, as shown in Table 5 below. Table 5 RFID Antenna Material Process characteristic Traditional RFID Antenna Aluminum foil 9 μm Print photoresist, bake, expose, develop, etch Frequency: 956.25 MHz Return Loss: -14.707 dB RFID antenna of the present invention Aluminum paste + copper sulfate solution Thick film printed aluminum electrodes, baked chemically replaced with copper electrodes Frequency: 937.5 MHz Return Loss: -24.248 dB

[Embodiment 4: Pre-treated silver-coated high-conductivity aluminum electrodes are applied to safety capacitors] Please refer to Figure 11 and Figure 18 to compare the process of manufacturing two- to three-side terminal electrode multilayer ceramic capacitors in the present invention and the current standard manufacturing five-side The flow chart of the manufacturing process of the terminal electrode multilayer ceramic capacitor, it can be seen that the two-to-three side terminal electrode multilayer ceramic capacitor of the present invention is in the original process of printing and sintering the inner nickel electrode, printing and sintering the upper and lower nickel terminal electrodes at the same time. The process uses electroplating or electroless plating to make the side terminal electrodes to form a new type of multilayer ceramic capacitor two- to three-side terminal electrodes. This innovative process can reduce two processes compared to the original five-side terminal electrode multilayer ceramic capacitors, including removing the original terminal electrodes. The immersion copper paste process and the copper terminal electrode are sintered at high temperature in a reducing atmosphere (nitrogen). The terminal electrode process of the two-to-three-side terminal electrode MLCC is to make both sides of the front and back electrodes respectively in the screen-printed inner electrode process, and then replace the copper side terminal electrodes with aluminum electrodes or use the electroplating or electroless plating terminal electrode process to make the other side. side electrodes. (a) Aluminum electrode replaces the side copper terminal electrode of electroless plating. First, the low temperature aluminum paste is dipped and baked to make the aluminum terminal electrode of the multilayer ceramic element, as shown in Figure 12(a), and then the aluminum terminal electrode is immersed. Copper sulfate solution, replace the aluminum terminal electrode with a copper terminal electrode, as shown in Figure 12 (b), the upper figure shows the surface of the copper terminal electrode, and the lower figure is a cross-sectional view of the copper terminal electrode. (b) Direct electroplating or electroless plating of side copper or nickel terminal electrodes Using electroplating technology, the multilayer ceramic capacitor is immersed in the cathode of copper sulfate or nickel sulfate solution. As shown in Figure 13, the anode nickel metal or copper metal can be oxidized to form copper or nickel ions. Due to the high density of the side electrodes of the MLCC as the cathode, copper ions or nickel ions can be reduced on the side electrodes of the MLCC to form side copper electrodes or side nickel electrodes, as shown in Figure 14. The multilayer ceramic capacitor uses the dense nickel inner electrode on the side, and uses wet chemical treatment (electroplating, general electroplating, substitution electroplating) to guide the structure of the nickel side terminal electrode. The left picture shows the surface of the nickel side terminal electrode, the middle picture and The figure on the right is a cross-sectional view of the nickel-side terminal electrode. At the same time, the results of the three-side nickel terminal electrode of the new laminated ceramic element are shown in Figure 15. The upper and lower nickel terminal electrodes are simultaneously fabricated by printing the inner nickel electrodes, and then the side dense nickel inner electrodes are used to wet chemical treatment (electroplating). , general chemical plating, displacement chemical plating) to produce three-sided nickel terminal electrodes. The electrical test, mechanical strength test and solderability test of the innovative two-to-three-side terminal electrode of the present invention and the original five-side terminal electrode are shown in Table 6. The results show that the test results of the two-to-three-side terminal electrode of the laminated ceramic component are slightly different. Better than the current pentagon electrode. Table 6 1206 Cap. μF tanD IR MΩ Pull test Bend test temperature cycle test Solderability test Innovative trilateral electrode 24.5 0.6% 10 ＞4kg ＞4.5mm 0/20 0/20 Original pentagonal electrode 22.7 0.5% 9 ＞3.5kg ＞4mm 0/20 0/20

[Embodiment 5: Pre-treated silver-coated high-conductivity aluminum electrodes are applied to safety capacitors]. In the present invention, an aluminum-silver core-shell structure is formed by chemically replacing the coated silver metal film on the metal aluminum powder, and then an aluminum-silver alloy (Ag ₂ Al) is formed by heat treatment. The conductivity of silver electrodes is close. Figure 16A shows that the thick-film printed silver-coated aluminum metal paste was sintered at 450°C, 500°C, 550°C, and 600°C, and its electrical conductivity was ^1x10-1 Ω*m, ^3x10-3 Ω*m, ^6x10-5 Ω*m, ^1x10-5 Ω*m; X-ray diffraction (XRD) analysis of Figure 16B shows that with the increase of sintering temperature, in addition to metal aluminum and metal silver, there is another The formation of Ag ₂ Al, the melting point of this item is about 550 ° C; the electron microstructure provided by scanning electron microscopy (SEM) in Figure 16C shows that all silver-coated aluminum metal pastes sintered at 550 ° C and At 600 °C, the microstructure has obvious changes, and there is a connection between the metal aluminum particles and the aluminum particles of Ag ₂ Al generation phase. Table 7 shows the characteristics of the current silver electrode used in safety capacitors. Although the conductivity of the innovative high-conductivity aluminum electrode of the present invention is slightly lower than that of the ordinary precious metal silver electrode, the safety capacitor is used as the electrode. The dielectric properties (C value = 0.35 nF and tanδ = 0.92%) and mechanical strength properties (tensile force = 1.75 kg) of the capacitors made from the new high-conductivity aluminum electrodes are comparable. Table 7 Electrode material Sintering temperature Electrode conductivity Safety Capacitor Capacitance Value Safety capacitor dissipation factor pull silver electrode 600~850°C 9x10 ^-6 (Ω*m) 0.36nF 0.91% 1.8kg

Therefore, the main technical features of the present invention are as follows: 1. After printing aluminum electrodes with thick film (containing copper sulfate crystals), they are placed in a copper solution, and the solution temperature and immersion time are controlled for chemical redox replacement. It becomes a kind of sintering under air, which can make high-conductivity copper electrodes. This copper electrode can be used in plastic flexible boards (low temperature 70-200°C), glass substrates (medium temperature 500-600°C), solar silicon Substrate (medium temperature 500-600°C), and ceramic substrate (high temperature 850-1000°C). 2. Applying this process to the solar front and back electrodes can replace the current front silver back aluminum electrodes of solar cells as copper electrodes, which can not only improve the photoelectric conversion efficiency but also greatly reduce the material cost. 3. Use solid crystal glue aluminum, or solid crystal tin compound paste (containing copper sulfate crystals), place it in copper solution, control the solution temperature and immersion time to carry out chemical redox replacement to become a kind of air sintering to become conductive. , High thermal conductivity copper solid crystal electrode. 4. The application of this process to chip packaging can replace the current tin and tin-lead solidification paste, which can meet the requirements of lead-free environmental protection and power electronic solidification packaging that requires high thermal conductivity. 5. Applying this process to RFID antenna production can achieve low material cost and low process cost, and the antenna characteristics are better than the current aluminum-copper film antenna. 6. The innovative high-conductivity copper electrode technology of the present invention can also be applied to medium-temperature glass substrates or high-temperature ceramic substrates. Aluminum electrodes are printed with thick films, sintered at different temperatures, such as packaged glass substrates or LED ceramic heat-dissipating substrates, and then immersed. In the copper solution, the temperature of the solution and the immersion time are controlled to carry out chemical redox replacement to become a high-conductivity copper solid crystal or copper electrode by sintering under air. 7. The present invention uses a chemical or physical coating film to form a core-shell structure on the surface of metal aluminum particles, uses sintering and heating to generate coated metal and aluminum alloy, and uses liquefaction of the alloy to connect the most densely packed aluminum particles to achieve ultra-high conductivity. For film-printed aluminum electrodes, this innovative technology follows the general thick-film printing and sintering process without further chemical replacement treatment, and can obtain a conductivity comparable to that of sintered printed silver electrodes in air or sintered copper electrodes in a reducing atmosphere. 8. The present invention uses this high-conductivity thick-film aluminum paste that does not require further chemical replacement treatment, and can be printed on the surface electrodes of various disc-shaped and block-shaped ceramic components, such as safety capacitors, GPS antennas, thermistors (NTC, PTC) , varistor, etc. can be applied to all the components of the electrode on the surface. Since the conductivity is matched with silver, the component characteristics are comparable to the current precious metal silver electrodes, but the material cost can be greatly reduced. 9. The terminal electrode of the multilayer ceramic component is a two- to three-side terminal electrode structure, including a front electrode, a back electrode and a front side electrode three sides. The electrodes have three sides with the positive side electrodes, and two electrodes on the left and right sides. 10. The front and back electrodes are made by screen printing and sintering, and the front and side electrodes are made by low temperature electroplating or electroless plating (electroless plating) process, or sputtering process. 11. Use nickel, copper or silver screen printing conductive paste to make front and back end electrodes, and use chemical solution copper, nickel, silver electroplating or electroless plating to make side third electrodes. 12. In order to increase the inner electrode density on the side of the laminated ceramic element, the inner electrode of the laminated ceramic element is printed on the green ceramic embryo, and the terminal electrode near the end of the element is also screen printed to increase the density of the side electrode, so as to facilitate subsequent electroplating or chemical treatment. Plating chemical treatment.

And, the key technical feature difference between the present invention and the prior art is: 1. It can be sintered in air without sintering in a reducing atmosphere to produce copper electrodes with high conductivity and copper solidification technology. 2. It can be sintered in air without chemical treatment to produce high-conductivity aluminum electrodes and aluminum solid crystal technology. 3. The low-temperature and high-conductivity copper electrodes or solid-crystal properties produced by this innovative technology at temperatures below 200°C are comparable to the current low-temperature high-conductivity silver electrodes or solid-state silver electrodes made with very expensive nano-silver pastes on the market. . 4. Pre-treatment coated metal high-conductivity thick-film aluminum electrodes can be applied to disc-shaped ceramic components, metal plates, glass substrates, or co-fired internal electrodes with low-temperature ceramic green embryos. 5. The printing of laminated ceramic components, low-temperature electroplating, and electroless plating are used to make two to three-sided terminal electrodes to replace the current five-sided terminal electrodes that use immersion plating and high-temperature sintering.

This innovative technology utilizes low-cost aluminum paste to print and sinter (containing copper sulfate crystals) before placement Replacing copper electrodes can meet the two major demands of low material and low process cost. The commercial application includes replacing relevant precious metal electrodes with copper electrodes, mainly replacing the screen-printed silver electrodes currently used in mass production in the industry as the primary application area.

1. Green energy industry (a) Solar front and back electrodes: the front and back electrodes of silicon-based solar cells are applied, and the copper paste of screen-printed copper electrodes is used to replace the current silver paste of solar screen-printed front and back silver electrodes. Generally, the average cost of copper paste for making copper electrodes is one tenth of that for making silver electrodes, and this innovative copper electrode manufacturing process can also make ultra-fine wires (<30 μm) to improve solar cell efficiency. (b) LED heat-dissipating ceramic substrate electrodes: metal wires applied to LED heat-dissipating ceramic substrates (Al ₂ O ₃ , AlN) are replaced by screen-printed copper electrodes for simple thick-film projects using vacuum sputtering, yellow light Compared with the complex process technology of the electroplating process, the manufacturing cost can be greatly reduced due to the simplification of the process.

2. Communication industry (a) Planar inductor electrode: replace the low temperature silver electrode of the touch panel or the electroplated copper electrode by vacuum sputtering. (b) Low-temperature ceramic co-fired components or module electrodes: applied to metal electrodes used in light, thin, short and small laminated ceramic communication passive components, and high aspect ratio metal copper electrode planar inductors are produced by printing, exposure, and etching to replace the current use of silver paste. When the inner electrode of the multilayer ceramic inductor is used, both the metal material cost and the process cost can be greatly reduced. (c) Touch panel electrodes: It can be applied to ceramic substrates or ceramic green embryos. It can be used to make thin wires, and the multilayer ceramic process can be used to develop ultra-small communication modules, which meet the technical requirements of short, light and thin portable communication products.

3. Semiconductor packaging industry It can be applied to wires, pads and die-bonding in the packaging industry, especially power electronic packaging that requires high thermal conductivity.

4. Passive component industry (a) Multilayer ceramic capacitors: Using this innovative electroplating or electroless copper or nickel electrode technology, the terminal electrodes of laminated ceramic capacitors can be made, and copper or nickel substitution electroless plating technology, or direct electroplating or direct electroless plating can be used. Copper and Nickel The side terminal electrodes of the multilayer ceramic capacitor are made of copper or nickel side terminal electrodes. The multilayer ceramic capacitor of the present invention utilizes nickel inner electrode chemical wet treatment to lead out copper or nickel side terminal electrodes. (b) Chip resistance: This innovative technology can produce ultra-low resistance copper-nickel, copper-manganese-nickel and nickel-chromium-silicon alloys. (c) Inductors: This innovative technology can produce thin film inductors and chips with copper electrodes fired under air The three-sided copper terminal electrode of the inductor. (d) Low Temperature Co-fired Ceramic (LTCC) element: this innovation The technology can produce surface copper electrodes and three-sided copper terminal electrodes of low-temperature co-fired ceramic components that burn copper electrodes under air.

To sum up, the present invention relates to a method for making a high-conductivity wire and an alloy material and the The innovative trilateral shape terminal electrode manufacturing method for multilayer ceramic components can effectively improve the conventional shortcomings. A high-conductivity electrode manufacturing process using base metal aluminum material and sintering in air is proposed, which can meet the requirements of low material and low process cost. It can be applied to various substrates, including plastic flexible boards (low temperature), glass substrates (medium temperature), solar silicon substrates (medium temperature) and ceramic substrates (high temperature). The proposed two innovative material methods can improve thick film The conductivity of the aluminum electrode is comparable or close to that of the thick-film printed silver electrode or the copper electrode sintered in a reducing atmosphere. The problems of product quality and high material process cost of pentagon electrode plating and high temperature reducing atmosphere sintering make the invention more advanced, more practical, and more in line with the needs of users, which has indeed met the requirements of the invention patent application , to file a patent application in accordance with the law.

However, the above descriptions are only preferred embodiments of the present invention, and should not be limited to this Therefore, any simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the contents of the description of the invention should still fall within the scope covered by the patent of the present invention.

(Part of the present invention) 11: Aluminum particles 12: Metal solution 13: Copper particles 21: Thick film aluminum layer 22: Metal solution 23: Thick film copper layer 24: thick film nickel layer 25: Thick film copper-nickel alloy layer 31: Aluminum particles 32: Metal film 33: Aluminum shell metal alloy 41: Nickel inner electrode 42: Guide copper electrodes 43: Copper terminal electrode (habitual part) 1: Internal electrode 2: Ceramic body 3: Terminal electrode 4: Front end electrode 5: Back end electrode 6: Side electrode

Fig. 1 is a schematic diagram of the redox reaction of copper particles replacing aluminum particles and copper thick film replacing aluminum thick film of the present invention. Figure 2 is a schematic diagram of the present invention utilizing the redox reaction of metals to perform replacement. Figure 3 is a schematic diagram of the front and back of the high-conductivity copper electrode of the present invention applied to various substrates. Fig. 4 is a schematic diagram of the present invention using large and small coated metal aluminum particles to achieve the most densely packed arrangement of thick film aluminum electrodes. Figure 5 is a schematic diagram showing the comparison of the structures of the two-to-three-side terminal electrodes of the multilayer ceramic capacitor of the present invention and the conventional five-side terminal electrodes of the multilayer ceramic capacitor. Fig. 6 is a schematic diagram of the increase of the density of the inner electrodes on the side of the two to three side end electrodes of the multilayer ceramic capacitor of the present invention. Fig. 7 is a schematic diagram of the increase of the density of the inner electrodes on the side of the two to three side end electrodes of the multilayer ceramic inductor of the present invention. Figure 8 is a schematic diagram of the increase of the density of the inner electrodes on the side of the two to three side end electrodes of the low temperature ceramic co-fired LTCC filter of the present invention. Figure 9A is a schematic diagram of the present invention converting the back aluminum electrode of the double-sided solar energy into a high-conductivity copper electrode. Fig. 9B is a schematic diagram of improving the photoelectric conversion efficiency of the solar cell after converting the back aluminum electrode of the double-sided solar energy into a high-conductivity copper electrode according to the present invention. Figure 10 is a schematic diagram of the adhesion test results between the low-temperature copper solidification of the present invention and the nanosilver solidification currently on the market. Fig. 11 is a schematic diagram of the manufacturing process of the two- to three-side terminal electrodes of the multilayer ceramic capacitor of the present invention. Fig. 12 shows the result of the present invention using low-temperature aluminum paste to fabricate the terminal electrode of the laminated ceramic element, and then replacing it with copper sulfate into the copper terminal electrode. Figure 13 is a schematic diagram of the present invention using electroplating (electroless plating) of the side electrodes of the multilayer ceramic capacitor. Fig. 14 is the result of the structure of the multilayer ceramic capacitor of the present invention, which uses the dense nickel inner electrode on the side to lead out the nickel side terminal electrode by wet chemical treatment. Fig. 15 is the result of the two-to-three-side terminal electrodes of the multilayer ceramic capacitor of the present invention. Figure 16A is a schematic diagram of the electrical conductivity of the thick-film printing silver-coated aluminum metal paste of the present invention sintered at different temperatures. Figure 16B is the XRD pattern of Ag ₂ Al formed in the present invention as the sintering temperature increases. Figure 16C is a SEM image of the microstructure of the silver-coated aluminum metal paste of the present invention sintered at different temperatures. Fig. 17 is a schematic diagram of the structure of the conventional five-side terminal multilayer ceramic capacitor and the conventional three-side terminal chip resistor. Figure 18 is a schematic diagram of the manufacturing process of the conventional MLCC's penta-terminal electrodes. Figure 19 is a schematic diagram of the actual sample of the conventional five-side terminal multilayer ceramic capacitor and the conventional three-side terminal chip resistor.

31: Aluminum particles

32: Metal film

33: Aluminum shell metal alloy

Claims (12)

A method for manufacturing high-conductivity wires, alloys and new-shaped terminal electrodes, which is to coat a thin metal film on the surface of several metal aluminum particles by chemical or physical methods to form a core-aluminum-shell metal structure, and use sintering and heating to make the shell metal An aluminum shell metal alloy is formed with the outside of the core aluminum, and then the temperature is raised to a sintering temperature of 300-660°C exceeding the melting point of the aluminum shell metal alloy, and the aluminum shell metal alloy is liquefied to connect the most densely packed surrounding metal aluminum particles. , you can make high-conductivity thick-film aluminum paste for high-conductivity thick-film aluminum electrodes. According to the method for manufacturing high-conductivity wires, alloys and new-shaped terminal electrodes as described in item 1 of the scope of the patent application, the metal film of the coating is a silver metal film, and the metal alloy of the aluminum shell is an aluminum-silver alloy (Ag ₂ Al). According to the method for manufacturing high-conductivity wires, alloys and new-shaped terminal electrodes as described in item 1 of the scope of the patent application, the metal aluminum particles are arranged in the form of the most densely packed with particle sizes of 5 μm and 2 μm. According to the method for manufacturing high-conductivity wires, alloys and new-shaped terminal electrodes as described in item 1 of the scope of the patent application, the high-conductivity thick-film aluminum paste can be printed on safety capacitors, GPS antennas, thermistors (NTC, PTC, etc.) ), varistor or all components that can be applied as electrodes on the surface. According to the method for manufacturing high-conductivity wires, alloys, and new-shaped terminal electrodes as described in item 1 of the scope of the patent application, the high-conductivity thick-film aluminum electrodes are suitable for use in disc-shaped ceramic components, metal plates, glass substrates, or other Low temperature ceramic green embryo co-firing inner electrode is used. A method for making high-conductivity wires, alloys and new-shaped terminal electrodes. After printing a thick-film aluminum layer with a high oxidation potential using a thick film, it is placed in a metal solution with a low oxidation potential, and the solution temperature and immersion are controlled. time to undergo chemical redox displacement reactions into thick film metal layers with low oxidation potential. According to the method for manufacturing high-conductivity wires, alloys and new-shaped terminal electrodes as described in item 6 of the claimed scope, the metal solution is copper sulfate, nickel sulfate, manganese sulfate, chromium sulfate, silicon compound or a combination thereof. According to the method for manufacturing high-conductivity wires, alloys and new-shaped terminal electrodes as described in item 6 of the patent application scope, the thick-film metal layer is a thick-film copper layer, a thick-film nickel layer, a thick-film copper-nickel alloy layer, a thick-film copper-nickel alloy layer, a thick-film Thin-film copper-manganese-nickel alloy layer, or thick-film nickel-chromium-silicon alloy layer. According to the method for manufacturing high-conductivity wires, alloys and new-shaped terminal electrodes as described in item 6 of the scope of the patent application, the thick-film metal layer is sintered in air to become high-conductivity copper electrodes or copper solid-state electrodes. According to the method for manufacturing high-conductivity wires, alloys, and new-shaped terminal electrodes as described in item 9 of the scope of the patent application, the copper electrodes are used in the manufacture of plastic flexible boards, glass substrates, solar silicon substrates and other materials ranging from low-temperature heat treatment to high-temperature sintering. A ceramic substrate and a new shape terminal electrode for making a multilayer ceramic capacitor, wherein the processing temperature of the plastic soft board is a low temperature of 70-200°C, the processing temperature of the glass substrate is a medium temperature of 500-600°C, and the processing temperature of the solar silicon substrate is The medium temperature is 500-600°C, and the processing temperature of the ceramic substrate is a high temperature of 850-1000°C. The method for manufacturing high-conductivity wires, alloys, and new-shaped terminal electrodes according to item 10 of the scope of the patent application, wherein the new-shaped terminal electrodes of the multilayer ceramic capacitor use copper or nickel to replace the copper or nickel of the multilayer ceramic capacitor by electroless plating. The side terminal electrodes of the multilayer ceramic capacitor, the low temperature side terminal electrode manufacturing process of the multilayer ceramic capacitor plus the printing of the inner electrodes to make the upper and lower terminal electrodes, can produce the three-sided new shape terminal electrodes of the multilayer ceramic capacitor. The method for manufacturing high-conductivity wires, alloys and new-shaped terminal electrodes according to claim 11, wherein the side terminal electrodes of the multilayer ceramic capacitor are fabricated by conventional electroplating, electroplating, and sputtering methods to make the copper of the multilayer ceramic capacitor. or nickel side electrodes.

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