WO2022246589A1 - Method for manufacturing high-conductivity wire, alloy and new-shaped terminal electrode - Google Patents

Abstract

A method for manufacturing a high-conductivity wire, an alloy and a new-shaped terminal electrode, which improves the conductivity of a thick-film aluminum electrode, such that the conductivity thereof is equal to or close to that of a thick-film printed silver electrode or a copper electrode, which is sintered in a reducing atmosphere, and manufacturing the terminal electrode of a new-shaped laminated ceramic assembly comprises replacing the thick-film aluminum electrode with a high-conductivity thick-film metal or alloy electrode by means of chemical oxidation-reduction replacement; and coating a thin film on the surface of metal aluminum particles by means of a chemical or physical process to form a core-shell structure, sintering and heating same to generate a film-coated metal and aluminum alloy, and then liquefying the alloy to connect same with the closest packed aluminum particles to obtain a thick-film printed aluminum electrode with ultra-high conductivity. By being applied to the terminal electrodes of laminated ceramic assemblies, pentagonal terminal electrodes, which are dipped and sintered at a high temperature, are changed into low-temperature two-three-sided terminal electrodes, which are printed and made by wet electroplating or chemical plating.

Description

High Conductivity Wire, Alloy and New Shape Terminal Electrode Manufacturing Method technical field

The invention relates to a high-conductivity wire, an alloy and a method for making a terminal electrode of a laminated ceramic assembly with a new shape, and in particular to a method that can improve the conductivity of a thick-film aluminum electrode and a thick-film printed silver electrode or a reducing atmosphere High-conductivity wires and alloys with comparable or close electrical conductivity to the lower sintered copper electrode, especially a thick-film aluminum electrode (including replacement metal) replaced by a high-conductivity thick-film copper electrode or It is other metals such as nickel and alloys; the other refers to the sintering of thick-film printed aluminum (including replacement metal) electrodes without further chemical replacement treatment, that is, the electrical conductivity of sintered printed silver electrodes in air or sintered copper electrodes in reducing atmosphere can be obtained Correspondingly high-conductivity wires or other metals such as nickel and alloys; using this material innovation technology can innovate the application of new electrode shapes, and the current multilayer ceramic components of passive components can be transformed into five-sided terminal electrodes that are dipped and high-temperature fired. It can be used as a low-temperature two-to-three-sided terminal electrode for printing and wet electroplating or electroless plating.

Background technique

At present, the mainstream material of metallization technology in the market is thick-film printed silver electrodes. Although the manufacturing process can be sintered under air, 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 temperature, so it must be protected under a reducing atmosphere such as nitrogen to avoid oxidation of copper electrodes, which leads to expensive process costs. In addition, when the ultra-low temperature sintering is less than 200°C, it is necessary to use nano-silver powder to make nano-silver paste to obtain a dense and high-conductivity silver electrode. 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 are precious metal materials, 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. Processing to produce, resulting in a substantial increase in production costs, which is not conducive to competition in the market; for example, thick film printing copper paste must be sintered in a nitrogen atmosphere to prevent oxidation, resulting in expensive process costs.

Thick-film printed aluminum electrodes can be sintered in air with low process cost, and the raw materials are also very cheap. The only biggest disadvantage is that there will be an extremely thin aluminum oxide film on the surface of thick-film metal aluminum powder particles, resulting in the metal of thick-film printed aluminum electrodes Aluminum powder cannot shrink during sintering to achieve densification, and the presence of aluminum oxide layer blocks the contact of metal aluminum particles, so the conductivity of thick-film aluminum electrodes is much lower than that of general thick-film silver electrodes or copper electrodes, and its conductivity is only Thick-film printing silver electrodes sintered under air or copper electrodes sintered under reducing atmosphere are 1/500 to 1/1000. At present, only solar cells are used as reflective and large-area back electrodes in the thick-film conductor market.

In addition, in terms of electrode shape, please refer to Table 1 below. At present, there are mainly two types of terminal electrode manufacturing technologies for passive components. The first is the five-sided terminal electrode technology. Its structure is shown in Figure 17a. The internal electrode 1 is stacked on the ceramic body Inside 2, both ends are terminal electrodes 3. The main process is shown in Figure 18. It is integrally formed by dip-plating process, and then undergoes high-temperature heat treatment. If it is copper or nickel conductive paste, it must be heat-treated in a reducing atmosphere to avoid oxidation. The second is the three-sided terminal electrode technology, its structure is shown in Figure 17b, the main process is to use screen printing to make the front terminal electrode 4, the back terminal electrode 5 and burn, and then use sputtering to make the side terminal electrodes 6. In terms of the appearance shape of the formed terminal electrode, the first type of terminal electrode formed by immersion plating is likely to have a moon edge shape, as shown in Figure 19a, and the second type of terminal electrode formed by printing and sputtering on three sides is square No moon edge shape, as shown in Figure 19b.

Table 1 Comparison of two terminal electrode fabrication technologies for current passive components

At present, the technology of multilayer ceramic capacitors is developing towards the direction of using thin dielectric layers and high capacitance values of multi-layer internal electrodes. Because the multilayer ceramics and internal electrodes share the same back, internal stress is likely to be generated due to the shrinkage mismatch between the metal electrodes and the ceramic green body. , when the terminal electrode is fired at high temperature, the internal stress is easy to release energy and cause cracks in the component. Therefore, the lower the firing temperature of the terminal electrode, the better is the current research and development trend. In addition, the component size of the laminated ceramic capacitor is also getting smaller. The smaller the size, the more precise the manufacturing of the terminal electrodes, and the higher the requirements for the squareness of the shape.

In view of the problems of the above-mentioned known technologies, in order to solve both problems, develop a method that can improve the conductivity of thick-film printed aluminum electrodes and conduct electricity with thick-film printed silver electrodes sintered under air or copper electrodes sintered under reducing atmosphere. The rate is quite or close, and can be further combined with new material innovations. It is necessary to use the three-sided terminal electrode technology of similar chip resistors to make multilayer ceramic capacitors.

Contents of the invention

The main purpose of the present invention is to overcome the above-mentioned problems encountered by the known technology, and provide a method for manufacturing high-conductivity wires, alloys and new-shaped terminal electrodes, and propose two innovative methods that can improve the conductivity and conductivity of thick-film aluminum electrodes. The conductivity of thick-film printed silver electrode or copper electrode sintered in reducing atmosphere is equal or close.

Another object of the present invention is to provide a method for manufacturing high-conductivity wires, alloys, and terminal electrodes with new shapes. The sintering of thick-film printed aluminum electrodes does not require further chemical replacement treatment, that is, sintered printed silver electrodes under air or reduced The electrical conductivity of the sintered copper electrode under the atmosphere is equivalent.

In order to achieve the above purpose, the technical solution adopted by the present invention is: a method for manufacturing high-conductivity wires, alloys and new-shaped terminal electrodes. Metal film to form a core aluminum shell metal structure, use sintering to raise the temperature to form an aluminum shell metal alloy between the shell metal and the outside of the core aluminum, and then raise the temperature to 300-660 ° C above the sintering temperature of the aluminum shell metal alloy melting point, use liquefaction The aluminum shell metal alloy is used to connect the most densely packed and arranged metal aluminum particles around, and without further chemical replacement treatment, a high-conductivity thick-film aluminum paste for a high-conductivity thick-film aluminum electrode can be produced.

In the above-mentioned embodiments of the present invention, the metal film of the covering film 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 arranged in the most densely packed form with particle sizes of 5 μm and 2 μm.

In the above embodiments of the present invention, the high-conductivity thick-film aluminum paste 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), pressure sensitive Resistors or all components that can be applied on a surface as electrodes.

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

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 produce a base metal conductive thick film or alloy thick film with high conductivity High-efficiency wires, alloys and methods for making terminal electrodes with new shapes.

In order to achieve the above purpose, the present invention adopts a method for manufacturing high-conductivity wires, alloys, and new-shaped terminal electrodes. The method is to use a thick film to print a high-oxidation potential thick-film aluminum layer (including replacement metal), and then place Put it in a metal solution with low oxidation potential, control the solution temperature and immersion time to carry out chemical redox replacement reaction to form a thick metal layer with low oxidation potential.

In the above embodiments of the present invention, the metal solution may be copper sulfate, nickel sulfate, manganese sulfate, chromium sulfate, silicon compound or a combination thereof.

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

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

In the above-mentioned embodiments of the present invention, the copper electrode can be applied to plastic soft boards, glass substrates, solar silicon substrates and ceramic substrates from low-temperature heat treatment to high-temperature sintering, and to make new-shaped terminal electrodes of innovative multilayer ceramic capacitors. The processing temperature of the plastic flexible board is low temperature 70-200°C, the glass substrate processing temperature is medium temperature 500-600°C, the solar silicon substrate processing temperature is medium temperature 500-600°C, and the ceramic substrate processing temperature is high temperature 850-1000°C.

In the above-mentioned embodiment of the present invention, the terminal electrode of the new shape of the multilayer ceramic capacitor is the side electrode of copper or nickel of the multilayer ceramic capacitor made of copper or nickel substitution electroplating, and the low-temperature side electrode manufacturing process of the multilayer ceramic capacitor is In addition to the printing of the inner electrode to produce the upper and lower end electrodes, it can be used to produce two-side or three-side new-shaped end electrodes of MLCCs.

In the above-mentioned embodiments of the present invention, the side-end electrodes of the MLCC can be further fabricated into copper or nickel side-end electrodes of the MLCC by common (conventional) electroless plating, electroplating and sputtering.

Description of drawings

Fig. 1 is the schematic diagram of redox reaction copper particle replacement aluminum particle and copper thick film replacement aluminum thick film of the present invention,

Among them: a is the replacement of aluminum particles by copper particles, and b is the replacement of aluminum thick films by copper thick films.

Fig. 2 is a schematic diagram of the present invention utilizing metal oxidation-reduction reactions for replacement.

Fig. 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 most densely packed arrangement of the thick-film aluminum electrodes achieved by using large and small film-coated aluminum particles in the present invention.

Fig. 5 is a comparative schematic diagram of two to three side terminal electrodes of a multilayer ceramic capacitor of the present invention and a known five side terminal electrode structure of a multilayer ceramic capacitor,

Wherein: a is the second to third terminal electrodes of the multilayer ceramic capacitor of the present invention, and b is the five-side terminal electrode of the known multilayer ceramic capacitor.

Fig. 6 is a schematic diagram of increasing the inner electrode density of the side electrodes of the multilayer ceramic capacitor of the present invention from two to three side electrodes,

Among them: a is a multilayer ceramic capacitor, and b is the cross-section of a to increase the electrode density on the side.

Fig. 7 is a schematic diagram of increasing the inner electrode density on the side of the multilayer ceramic inductor of the present invention by increasing the electrode density on two to three sides,

Among them: a is the multilayer ceramic inductor, b is the cross-section a increases the inner electrode density on the side; a1-coil, a2-external electrode, a3-non-magnetic ceramics.

Fig. 8 is a schematic diagram of increasing the inner electrode density of the side electrodes of the low-temperature ceramic co-fired LTCC filter of the present invention on two to three sides,

Among them: a is a low-temperature ceramic co-fired LTCC filter, and b is the cross-section of a to increase the electrode density on the side.

Fig. 9a is a schematic diagram of converting the back aluminum electrode of double-sided solar energy into a copper electrode with high conductivity according to the present invention.

Figure 9b is a schematic diagram of the improvement of 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 in the present invention. The figure shows the best state of the double-sided solar module and the front surface and data on the back surface.

Figure 10a is a schematic diagram of the test results of the adhesion between the low-temperature copper crystal bonding of the present invention and the nano-silver crystal bonding currently on the market,

Among them: a1-low temperature copper solidification (copper replacement aluminum), a2-Heraeu.

Fig. 10b is a microstructure diagram of low-temperature copper crystal solidification (copper replacement for aluminum) of the present invention,

Among them: b1-diode, b2-copper replacement aluminum, b3-gold-plated substrate.

Fig. 11 is a schematic diagram of the manufacturing process of the second to third side terminal electrodes of the laminated ceramic capacitor of the present invention.

Fig. 12a is a diagram of terminal electrodes of a laminated ceramic assembly made of low-temperature aluminum paste according to the present invention.

Fig. 12b is a diagram of the result of submerging the terminal electrode of the laminated ceramic component in a copper sulfate solution and replacing it with a copper terminal electrode according to the present invention,

Among them: the upper figure shows the surface of the copper terminal electrode, and the lower figure is the cross-sectional view of the copper terminal electrode.

Fig. 13 is a schematic diagram of the present invention using electroplating (electroless plating) on the side end electrodes of a laminated ceramic capacitor.

Fig. 14 is a result diagram of the structure of the nickel side end electrode guided by the wet chemical treatment of the multilayer ceramic capacitor of the present invention using the side dense nickel inner electrode,

Among them: the left picture is the surface of the nickel side end electrode, the middle picture and the right picture are the cross-sectional views of the nickel side end electrode.

Fig. 15 is a diagram showing the results of the three-sided terminal electrodes of the multilayer ceramic capacitor of the present invention.

Fig. 16a is a schematic diagram of the electrical conductivity of the thick-film printing silver-clad aluminum metal paste of the present invention sintered at different temperatures.

Fig. 16b is the XRD pattern of Ag2Al formed with the increase of sintering temperature in the present invention.

Fig. 16c is an SEM image of the microstructure of the silver-clad aluminum metal paste of the present invention sintered at different temperatures.

Fig. 17 is a structural schematic diagram of a known five-sided multilayer ceramic capacitor and a known three-sided chip resistor,

Among them: a-the five-sided terminal electrode, b-the second-three-sided terminal electrode.

Fig. 18 is a schematic diagram of the manufacturing process of the five-sided terminal electrode of the known laminated ceramic capacitor.

Figure 19 is a schematic diagram of actual samples of a known five-sided multilayer ceramic capacitor and a known three-sided chip resistor,

Among them: a-the five-sided terminal electrode, the arrow points to the shape of the moon; b-the two-three-sided terminal electrode, the arrow indicates that the terminal electrode is square without the shape of the moon.

Label comparison:

Aluminum particles 11

Metal Solution 12

Copper Particles 13

Thick film aluminum layer 21

Metal solution 22

thick film copper layer 23

thick film nickel layer 24

Thick film copper-nickel alloy layer 25

Aluminum particles 31

Metal film 32

Aluminum shell metal alloy 33

Nickel inner electrode 41

Guide copper electrode 42

Copper terminal electrodes 43 .

Detailed ways

Please refer to Figures 1-16c, which are the schematic diagrams of redox reaction copper particles replacing aluminum particles and copper thick film replacing aluminum thick film in the present invention, the replacement schematic diagram of metal redox reaction in the present invention, and the highly conductive film of the present invention. Schematic diagram of the application of high-rate copper electrodes on the front and back of various substrates, the present invention uses large and small film-coated aluminum particles to achieve the most densely packed arrangement of thick-film aluminum electrodes, and the second to third sides of the multilayer ceramic capacitor of the present invention Schematic diagram of electrode structure comparison with known multilayer ceramic capacitor five-side terminal electrode, multilayer ceramic capacitor of the present invention with two to three side terminal electrodes increasing side electrode density schematic diagram, multilayer ceramic inductor of the present invention with two to three sides Schematic diagram of terminal electrode increasing side inner electrode density, low-temperature ceramic co-fired LTCC filter of the present invention on two to three side end electrodes increasing side inner electrode density schematic diagram, this invention converts the back aluminum electrode of double-sided solar energy into high conductivity copper The schematic diagram of the electrode, the schematic diagram of the photoelectric conversion efficiency improvement of the solar cell after the double-sided solar energy back aluminum electrode of the present invention is converted into a high-conductivity copper electrode, the attachment of the low-temperature copper crystal bonding of the present invention and the currently known nano-silver crystal bonding Schematic diagram of test results, a schematic diagram of the production process of the second to third side terminal electrodes of the multilayer ceramic capacitor of the present invention, a diagram of the terminal electrodes of the multilayer ceramic component made of low-temperature aluminum paste in the present invention, and the terminal electrode of the multilayer ceramic component dipped in sulfuric acid in the present invention Substitution of copper solution into copper terminal electrode results, the present invention utilizes the electroplating (electroless plating) of the side terminal electrodes of the multilayer ceramic capacitor to make the schematic diagram, and the multilayer ceramic capacitor of the present invention utilizes the side dense nickel inner electrode to lead out the nickel by wet chemical treatment The result diagram of the side electrode structure, the result diagram of the second to third side electrode of the multilayer ceramic capacitor of the present invention, the schematic diagram of the conductivity of the thick film printing silver-clad aluminum metal paste of the present invention sintered at different temperatures, and the present invention as the sintering temperature increases The XRD pattern of Ag ₂ Al and the SEM pattern of the silver-coated aluminum metal paste of the present invention sintered at different temperatures. As shown in the figure: the present invention is a method for manufacturing 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 crystals, solar cells, and ceramic component terminals. Electrodes, LED heat dissipation substrates and glass substrates. Two innovative methods are proposed to improve the conductivity of thick-film aluminum electrodes, which is equivalent or close to that of thick-film printed silver electrodes or copper electrodes sintered in a reducing atmosphere.

The first innovative method is the chemical replacement of thick-film aluminum electrodes (including replacement metals) with high-conductivity 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 metals to replace, as shown in Figure 1 and Figure 2. In FIG. 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 to perform a redox replacement reaction. In this embodiment, the aluminum particle 11 is replaced with a copper particle 13 . Similarly, in Figure 1b, if a layer of thick-film aluminum layer 21 with high oxidation potential (including replacement metal) is printed after sintering and immersed in a metal solution 22 with low oxidation potential, redox can also be performed after a period of immersion time. The substitution reaction becomes a thick-film metal layer with low oxidation potential. In this embodiment, the thick-film aluminum layer 21 is replaced by the thick-film copper layer 23 .

Because aluminum metal powder is quite cheap and has a high oxidation potential, it can be used as a sacrificial layer after surface pretreatment with hydrofluoric acid. As shown in Figure 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 thick-film aluminum Layer 21 becomes thick-film copper layer 23 or thick-film nickel layer 24, or even thick-film copper-nickel alloy layer 25 or copper-manganese-nickel, nickel-chromium-silicon alloy layer.

As shown in Figure 3, this innovative method is used to manufacture various substrates, from left to right in the figure are ceramics, PET film (thick sheet), PET film (thin sheet), glass substrate and aluminum alloy casing. A high-conductivity copper wire that does not need to be sintered in a reducing atmosphere is produced. The upper row is the front of the substrate, and the lower row is the back of the substrate.

The second innovative method is a high-conductivity thick-film aluminum electrode with aluminum powder pretreatment. In order to improve the conductivity of thick-film aluminum electrodes, this innovative method is to coat a layer of thin metal film 32 chemically or physically on the surface of metal aluminum particles 31 with different particle sizes to form a core (aluminum) shell (metal ) structure, using sintering to raise the temperature to form an aluminum shell metal alloy 33 between the shell metal and the core aluminum, and then heat up to 300-660°C to a sintering temperature exceeding the melting point of the aluminum shell metal alloy to liquefy the aluminum shell metal alloy To connect the surrounding metal aluminum particles 31 densely packed and arranged to improve the conductivity of the overall thick-film aluminum electrode. Metal aluminum particles 31 with a small particle size of 2 μm are used to achieve the most densely packed arrangement of thick-film aluminum electrodes. In this way, the front-coated metal film 32 is used to form a metal-film aluminum alloy and liquefy to connect each metal aluminum powder. The conductivity of thick-film aluminum electrodes is equivalent to that of mainstream thick-film silver electrodes or copper electrodes in the current market.

The present invention uses the above-mentioned innovative high-conductivity materials to make a new shape of the terminal electrode of an innovative laminated ceramic component, and changes the shape of the pentagonal terminal electrode that is currently used for immersion plating and high-temperature firing to one that is deposited by printing and electroplating or electroless plating. Bilateral or triangular terminal electrodes.

Table 2 and Figure 5 show the results of the comparison between the terminal electrode technology of the innovative multi-layer ceramic capacitors (MLCC) of the present invention and the currently known terminal electrode technology of multi-layer ceramic capacitors in terms of structure, process, material and characteristics Shown, wherein Fig. 5 a is the multilayer ceramic capacitor terminal electrode that the present invention's innovative multilayer ceramic capacitor terminal electrode (like chip resistor terminal electrode) technology makes, and Fig. 5 b is that the presently known multilayer ceramic capacitor terminal electrode technology makes Multilayer ceramic capacitor terminal electrodes. Table 2 can explain that this innovative technology is to change 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. As the shape of the terminal electrodes changes, the process method and materials used Also follow the change.

Table 2 Comparison table between the innovative MLCC terminal electrodes of the present invention and the known MLCC terminal electrodes

From the above comparison, it can be seen that the manufacturing process has been changed from the original immersion-plating integral forming and sintering heat treatment to printing the front and back electrodes and then co-firing with the ceramic green body, and then making the third side by low-temperature electroplating, electroless plating or sputtering processes. terminal electrode.

Compared with the current five-sided terminal electrode technology, the innovative two- to three-sided terminal electrode technology of this multilayer ceramic capacitor has at least four advantages:

1. The printing process replaces the immersion plating process to produce a square shape of the terminal electrode without a moon shape, which can improve the quality of the terminal electrode shape, especially for small-sized multilayer ceramic capacitors.

2. The ultra-low temperature process <100°C can improve and reduce the internal stress caused by the cracks caused by heat treatment of the terminal electrode in a high-temperature reducing atmosphere, and the innovative high-density and thin layer of the terminal electrode can improve the high-temperature sintering of the current copper paste containing glass. Copper terminal electrode quality problem.

3. Omit the current immersion plating process and reducing atmosphere high-temperature firing process for terminal electrodes of multilayer ceramic capacitors, which greatly reduces the process cost.

4. It is not necessary to use thick-film copper conductive paste, but to use copper or nickel chemical solution, which greatly reduces the cost of materials.

In addition, the novel two-three-sided terminal electrodes can be applied to multilayer ceramic components, such as multilayer ceramic capacitors (as shown in Figure 6a and Figure 6b), multilayer ceramic inductors (as shown in Figure 7a and Figure 7b) Co-fired LTCC filters with low-temperature ceramics (as shown in Figure 8a and Figure 8b), etc., can be printed on both ends of the component when the inner electrode is screen-printed. Electrodes, increase the electrode density of the side electrodes (as shown in FIG. 6b, FIG. 7b and FIG. 8b ), so that the side electrodes of the two to three side electrodes can be fabricated by electroplating or electroless plating in the later process.

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

Implementation Mode 1: Solar Cell

Figure 9A shows the back aluminum electrode of the solar electrode. After the innovative process proposed by the present invention, the original back aluminum electrode of double-sided solar energy can be converted into a high-conductivity copper electrode. Due to the increase in the conductivity of the electrode, the photoelectric conversion efficiency of the solar cell is also improved. As a result, the optimal state of the double-sided solar module and the data of the front surface and the rear surface in this optimal state are shown in FIG. 9B .

In the same manufacturing method, the current positive silver electrode of the solar cell can be printed into a high-conductivity positive aluminum electrode, and then the positive aluminum electrode is immersed in 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.

Implementation Mode 2: Encapsulation and Die Bonding

At present, tin-lead is the main material of die-bonding glue. In addition to environmental protection issues, insufficient thermal conductivity is another issue when it is applied to high-power die-bonding. Therefore, the current industry uses nano-silver that can be sintered at low temperature to replace the current tin-lead die-bonding. However, nano-silver is very expensive to use as a crystal-bonding paste. The innovative process of the present invention sinters high-conductivity crystal-bonding copper replacement aluminum paste (containing copper sulfate crystals) under low-temperature air to become low-temperature copper crystal-bonding and is currently on the market. Die-bonding silver paste (Heraeus) can produce very low-cost copper electrodes, and in terms of characteristics comparison, Figure 10a and Table 3 can illustrate the characteristics of this innovative process of low-temperature copper die-bonding (such as: adhesion, thermal conductivity and electrical conductivity) test results can be equivalent to the current nano-silver solid crystal, Figure 10b is the microstructure of the low-temperature copper solid crystal (copper replacement aluminum) described in Figure 10a, and Table 4 can show that the low-temperature copper solid crystal of the present invention The adhesion of the crystal (copper replacement aluminum) is comparable to that of the current nano-silver solid crystal (Heraeus).

Table 3 characteristic test result table of the present invention

Table 4 The adhesion comparison table of the present invention's low-temperature copper crystal bonding and nano-silver crystal bonding

the	Adhesion (kgf)	Adhesion (Mpa)
Silver Paste (85%) - Heraeus	7.5	15.9
The present invention - copper replacement aluminum	7.8	16.8

Implementation Mode Three: RFID Antenna

Generally, for making radio frequency identification (RFID) antennas, about 10 μm aluminum foil or copper foil is pasted on polyethylene terephthalate (PET) film, and then complicated printing, baking, and exposure , developing and etching subtractive processes to make RFID antennas; another method is the innovative process and materials of the present invention, which is to print thick film aluminum paste (containing copper sulfate crystals), bake and then perform chemical replacement in copper sulfate solution for 30 minutes Become a high-conductivity RFID copper antenna (in which the immersion time is controlled to form 0min aluminum; 5min slightly copper; 10min partial copper; 20min copper chemical replacement treatment), this process is an additive process to reduce material waste, the process equipment is simple, and the antenna The characteristic return loss is also -24.248dB better than -14.707dB of the etched RFID aluminum antenna, see Table 5 below.

Table 5 The low-temperature copper electrode application RFID antenna of the present invention and the traditional test result comparison of utilizing exposure development RFID aluminum antenna

Implementation Mode 4: Pre-treatment of silver-coated high-conductivity aluminum electrodes and application of safety capacitors

Please refer to FIG. 11 and FIG. 18 , comparing the flow charts of the manufacturing process of the multilayer ceramic capacitor with two- to three-side terminal electrodes and the currently known standard manufacturing process of the multilayer ceramic capacitor with five-side terminal electrodes, it can be seen that the innovation of the present invention is two ～Three-sided terminal electrode multilayer ceramic capacitors, in the original process of printing and sintering inner nickel electrodes, simultaneously print and sinter the upper and lower nickel terminal electrodes, and use electroplating or chemical plating to make side terminal electrodes in the original electroplating process, forming a new type The two- to three-side terminal electrodes of the multilayer ceramic capacitors. This innovative process can reduce two processes compared with the original five-side terminal electrode multilayer ceramic capacitors, including removing the immersion copper paste process made by the original terminal electrodes and the reduction of copper terminal electrodes. High temperature sintering process under atmosphere (nitrogen). For the terminal electrode process of two-to-three-side terminal electrode MLCC, the two sides of the front and back electrodes are produced respectively in the screen printing inner electrode process, and then the aluminum electrode is used to replace the copper side terminal electrode or the other is made by electroplating or chemical plating terminal electrode process. side electrodes.

(a) Aluminum electrode replaces electroless plating side copper terminal electrode

First, the low-temperature aluminum paste is dipped and baked to form an aluminum terminal electrode of a laminated ceramic component, as shown in Figure 12a, and then the aluminum terminal electrode is immersed in a copper sulfate solution to replace the aluminum terminal electrode with a copper terminal electrode. As shown in Figure 12b.

(b) Direct electroplating or electroless plating of side copper or nickel terminal electrodes

Using electroplating technology to immerse the laminated ceramic capacitor 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 generate copper ions or nickel ions. Due to the high density of the side electrode of the multilayer ceramic capacitor as the cathode, the copper ions or nickel ions can be reduced on the side electrode of the multilayer ceramic capacitor to form a side copper electrode or a side nickel electrode, 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 chemical plating, replacement electroplating) to guide the structure diagram of the nickel side end electrode, and the results of the new multilayer ceramic component three-side nickel end electrode As shown in Figure 15, the upper and lower nickel terminal electrodes are produced at the same time as the inner nickel electrode is printed, and then the side dense nickel inner electrode is used to produce three-sided Nickel terminal electrodes.

The electrical test, the mechanical strength test and the weldability test of the innovative two-three-side terminal electrodes of the present invention and the original five-side terminal electrodes are shown in Table 6, and the results show the test results of the two-three-side terminal electrodes of the multilayer ceramic component. Slightly better than the current five-sided terminal electrode.

Table 6 The present invention's innovative two-three-side terminal electrodes and the test comparison of known five-side terminal electrodes

Implementation Mode 5: Pre-treatment of silver-coated high-conductivity aluminum electrodes and application of safety capacitors

In the present invention, the aluminum-silver core-shell structure is formed by chemically displacing the film-coated silver metal film on the metal aluminum powder, and then an aluminum-silver alloy (Ag ₂ Al) is formed through heat treatment. The conductivity of the silver electrode is close. Figure 16a shows that the thick film printing silver-clad aluminum metal paste is sintered at 450°C, 500°C, 550°C and 600°C, and its conductivity is 1x10 ^-1 Ω*m, 3x10 ^-3 Ω*m, 6x10 ^-5 Ω *m, 1x10 ^-5 Ω*m; X-ray diffraction (XRD) analysis in Figure 16b shows that with the increase of sintering temperature, besides the metal aluminum and metal silver, there is another Ag ₂ Al formation , the melting point of this item is about 550°C; Figure 16c shows that the electron microstructure provided by Scanning electron microscopy (SEM) shows that all silver-coated aluminum metal pastes are sintered at 550°C and 600°C. Change, there is a connection of Ag ₂ Al generation phase between the metal aluminum particles and the aluminum particles.

Table 7 shows the characteristics of current silver electrodes used in safety capacitors. Although the conductivity of the innovative high-conductivity aluminum electrodes of the present invention is slightly lower than that of ordinary noble metal silver electrodes, the safety capacitors used as electrodes are comparable between ordinary silver electrodes and this The dielectric characteristics (C value = 0.35nF and tanδ = 0.92%) and the mechanical strength characteristics (pull force = 1.75kg) of the capacitor made of innovative high-conductivity aluminum electrodes are equivalent.

Table 7 Characteristics of current silver electrodes used in safety capacitors

Therefore, main technical feature of the present invention is as follows:

1. After printing aluminum electrodes (containing copper sulfate crystals) with a thick film, they are placed in a copper solution, and the temperature of the solution and the immersion time are controlled to carry out chemical redox replacement, which can be sintered under air to make high conductivity copper electrodes. , this copper electrode can be applied to plastic soft boards (low temperature 70-200 °C), glass substrates (medium temperature 500-600 °C), solar silicon substrates (medium temperature 500 °C) sintered from low temperature (70 °C) to high temperature (1000 °C) ~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 solar cell front and back aluminum electrodes with copper electrodes, which can not only improve the photoelectric conversion efficiency but also greatly reduce the cost of materials.

3. Use crystal-bonding aluminum or crystal-bonding tin compound paste (containing copper sulfate crystals), place it in the copper solution, control the solution temperature and immersion time to carry out chemical oxidation-reduction replacement to become a kind of sintering under air. Conductive, high thermal conductivity copper die-bonding electrodes.

4. Applying this process to chip packaging die bonding can replace the current tin and tin-lead die bonding paste, and can meet the requirements of lead-free environmental protection and the application of power electronic die bonding packaging that requires high thermal conductivity.

5. Applying this process to the manufacture of RFID antennas can achieve low material cost and low process cost, and the characteristics of the manufactured antenna 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 In the copper solution, the temperature of the solution and the immersion time are controlled to carry out chemical redox replacement and sinter in the air to form a highly conductive copper crystal or copper electrode.

7. The present invention utilizes a chemical or physical film to form a core-shell structure on the surface of metal aluminum particles, uses sintering to raise the temperature to generate film-coated metal and aluminum alloy, and liquefies the alloy to connect the most densely packed aluminum particles to achieve ultra-high conductivity. Film-printed aluminum electrodes, this innovative technology follows the general thick-film printing and sintering without further chemical replacement treatment, which can obtain the same conductivity as sintering printed silver electrodes in air or sintering copper electrodes in reducing atmosphere.

8. The present invention utilizes this high-conductivity thick-film aluminum paste without further chemical replacement treatment, which can be printed onto electrodes on the surface of various disc-shaped and block-shaped ceramic components, such as safety capacitors, GPS antennas, thermistors (NTC, PTC ), piezoresistors, etc. can be applied to all components on the surface as electrodes. Since the conductivity matches silver, the characteristics of the components are equivalent to the current noble metal silver electrodes, but the cost of materials can be greatly reduced.

9. The terminal electrode of the multilayer ceramic component is a two-to-three-sided terminal electrode structure, including three sides of the front electrode, the back electrode and the positive side electrode, which is different from the traditional multilayer ceramic capacitor which has a five-sided terminal electrode structure, including the front electrode. 1, the back electrode and the positive side electrode three sides, 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 electrodes at both ends of the front and back, and use chemical solution copper, nickel, silver electroplating or electroless plating to make the third electrode on the side.

12. In order to increase the electrode density on the side of the laminated ceramic component, the internal electrode of the laminated ceramic component is screen-printed on the ceramic green body, and the terminal electrode close to the end of the component is also screen-printed to increase the electrode density on the side for subsequent electroplating or It is electroless chemical treatment.

And, the key technical feature difference between the present invention and prior art is:

1. Can be sintered in air, without sintering in reducing atmosphere, can produce copper electrodes with high conductivity and copper solid crystal technology.

2. It can be sintered in the air without chemical treatment, and can produce high-conductivity aluminum electrodes and aluminum crystal-bonding technology.

3. The low-temperature high-conductivity copper electrodes or crystal-bonding characteristics manufactured by this innovative technology at temperatures below 200°C are comparable to the low-temperature high-conductivity silver electrodes or crystal-bonding made by using very expensive nano-silver powder paste on the market.

4. Pre-treatment Film-coated metal high-conductivity thick-film aluminum electrodes can be used in disc-shaped ceramic components, metal plates, glass substrates, or co-fired internal electrodes with low-temperature ceramic green bodies.

5. Printing of laminated ceramic components, low-temperature electroplating, and electroless plating to produce two to three-sided terminal electrodes to replace the current five-sided terminal electrodes that use immersion plating and high-temperature firing.

This innovative technology uses low-cost aluminum paste printing and sintering (containing copper sulfate crystals) and then replaces it with copper electrodes to meet the two major needs of low material and low process costs. It can be applied to commercial industries including replacing related precious metal electrodes with copper electrodes, mainly At present, the screen printing silver electrode used in mass production in the industry is the primary application field.

1. Green energy industry

(a) Front and back electrodes of solar energy: the front and back electrodes of silicon-based solar cells are used, 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, copper electrodes are produced on average The cost of the copper paste is one-tenth of the silver paste for making silver electrodes, and the innovative copper electrode process can also make ultra-fine wires (<30μm) to improve the efficiency of solar cells.

(b) LED heat-dissipating ceramic substrate electrodes: Metal wires applied to LED heat-dissipating ceramic substrates (Al ₂ O ₃ , AlN), replace the current application of thin-film engineering vacuum sputtering, yellow light with screen-printed copper electrodes of simple thick film engineering With the complex process technology of electroplating process, the manufacturing cost can be greatly reduced due to the simplification of the process.

2. Communication industry

(a) Planar inductive electrode: replace the low-temperature silver electrode of the touch panel or the copper electrode of vacuum sputtering plating.

(b) Low-temperature ceramic co-fired components or module electrodes: applied to metal electrodes used in thin, short and small multilayer ceramic communication passive components. Printing, exposure, and etching are used to make planar inductors with high aspect ratio metal copper electrodes to replace the current use of silver paste. When the inner electrode is used as a multilayer ceramic inductor, both the metal material cost and the manufacturing process cost can be greatly reduced.

(c) Touch panel electrodes: It can be applied to ceramic substrates or ceramic green bodies, using its ability to produce thin lines, and laminated ceramic manufacturing processes 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 (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: use this innovative electroplating or chemical plating copper or nickel electrode technology to make multilayer ceramic capacitor terminal electrodes, and use copper or nickel replacement electroplating technology, or direct electroplating or direct electroplating Electroless copper and nickel plating The side terminal electrodes on the boundary of the multilayer ceramic capacitor are made of copper or nickel side terminal electrodes.

The multilayer ceramic capacitor of the present invention utilizes nickel internal 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 three-sided copper terminal electrodes of chip inductors with copper electrodes burned out under air.

(d) Low Temperature Co-fired Ceramic (LTCC) components: This innovative technology can produce copper electrodes on the surface of low temperature co-fired ceramic components and three-sided copper terminal electrodes that are fired under air.

In summary, the present invention is a method for manufacturing high-conductivity wires and alloy materials and a method for manufacturing innovative triangular-shaped terminal electrodes of laminated ceramic components, which can effectively improve various shortcomings of the prior art, and propose the use of base metal aluminum materials and The high-conductivity electrode process produced by sintering in air can meet the two major requirements of low material and low process cost, and can be applied to various substrates, including plastic flexible boards (low temperature), glass substrates (medium temperature), and solar silicon substrates ( medium temperature) and ceramic substrate (high temperature), the proposed two innovative material methods can improve the conductivity of thick-film aluminum electrodes to be equal or close to those of thick-film printed silver electrodes or copper electrodes sintered in reducing atmosphere. The low-temperature terminal electrode manufacturing method of the new three-sided shape of the multilayer ceramic component can improve the product quality and high material process cost of the five-sided terminal electrode sintered by immersion plating and high-temperature reducing atmosphere in the current multilayer ceramic component, and then make the production capacity of the present invention It is more advanced, more practical, and more in line with the needs of users. It has indeed met the requirements for patent applications for inventions, and patent applications are filed in accordance with the law.

But the above is only a preferred embodiment of the present invention, and should not limit the scope of the present invention; All should still belong to the scope that the patent of the present invention covers.

Claims (12)

1. A method for manufacturing high-conductivity wires, alloys and new-shaped terminal electrodes, characterized in that the method is to chemically or physically coat a layer of thin metal film on the surface of several metal aluminum particles to form a core-aluminum-shell metal structure, Use sintering to raise the temperature to form an aluminum shell metal alloy between the shell metal and the core aluminum, and then raise the temperature to 300-660°C above the sintering temperature of the aluminum shell metal alloy melting point, and use the liquefaction of the aluminum shell metal alloy to connect the most dense surrounding A high-conductivity thick-film aluminum paste for a high-conductivity thick-film aluminum electrode can be produced by stacking and arranging metal aluminum particles.
2. The method for manufacturing high-conductivity wires, alloys, and new-shaped terminal electrodes according to claim 1, wherein the metal thin film of the coating is a silver metal thin film, and the metal alloy of the aluminum shell is an aluminum-silver alloy.
3. The method for manufacturing high-conductivity wires, alloys, and new-shaped terminal electrodes according to claim 1, wherein the metal aluminum particles are arranged in the most densely packed form with particle sizes of 5 μm and 2 μm.
4. The method for manufacturing high-conductivity wires, alloys, and new-shaped terminal electrodes according to claim 1, wherein the high-conductivity thick film aluminum paste can be printed on safety capacitors, GPS antennas, thermistors, pressure sensitive Resistors or all components that can be applied on a surface as electrodes.
5. The method for manufacturing high-conductivity wires, alloys, and new-shaped terminal electrodes according to claim 1, wherein the high-conductivity thick-film aluminum electrodes are suitable for use in disc-shaped ceramic components, metal plates, and glass substrates, or in conjunction with Low-temperature ceramic green body co-fired inner electrodes are used.
6. A method for manufacturing high-conductivity wires, alloys and new-shaped terminal electrodes, characterized in that the method is to use a thick film to print a thick-film aluminum layer with a high oxidation potential, and then place it in a metal solution with a low oxidation potential , control the solution temperature and immersion time to carry out chemical redox substitution reaction to form a thick metal layer with low oxidation potential.
7. The method for manufacturing high-conductivity wires, alloys and new-shaped terminal electrodes according to claim 6, wherein the metal solution is copper sulfate, nickel sulfate, manganese sulfate, chromium sulfate, silicon compounds or combinations thereof.
8. The manufacturing method of high-conductivity wires, alloys and new-shaped terminal electrodes as claimed in claim 6, wherein 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 metal layer Copper-manganese-nickel alloy layer, or thick-film nickel-chromium-silicon alloy layer.
9. The method for manufacturing high-conductivity wires, alloys and new-shaped terminal electrodes according to claim 6, wherein the thick-film metal layer is sintered in air to form a high-conductivity copper electrode or a copper crystal-bonding electrode.
10. The method for manufacturing high-conductivity wires, alloys, and new-shaped terminal electrodes as claimed in claim 9, wherein the copper electrodes are applied to plastic soft boards, glass substrates, solar silicon substrates and Ceramic substrates, and the production of new-shaped terminal electrodes for laminated ceramic capacitors, in which the plastic flexible board is treated at a low temperature of 70-200°C, the glass substrate is treated at a medium temperature of 500-600°C, and the solar silicon substrate is treated at a medium temperature of 500°C ~600°C, the processing temperature of the ceramic substrate is a high temperature of 850~1000°C.
11. The method for manufacturing high-conductivity wires, alloys, and new-shaped terminal electrodes as claimed in claim 10, wherein the new-shaped terminal electrodes of the laminated ceramic capacitors are made of copper or nickel-substituted electroless plating to produce laminated ceramic capacitors. Or nickel side-end electrodes, the low-temperature side-end-electrode manufacturing process of the multilayer ceramic capacitor plus the printing of the inner electrode to make the upper and lower end electrodes can produce two-side or three-side new-shaped end electrodes of the multilayer ceramic capacitor.
12. 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 capacitors are manufactured by conventional electroplating, electroplating and sputtering methods. side end electrodes of copper or nickel.

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