KR20240041514A - Multilayer ceramic substrate, and method for manufacturing the same - Google Patents

Abstract

The present invention relates to one or more ceramic layers; and an electrode formed on at least a portion of the ceramic layer, wherein the electrode includes a metal composite in which a copper layer is formed on at least a portion of the surface of the molybdenum particles. The present invention relates to a multilayer ceramic substrate and a method of manufacturing the same.

Description

Multilayer ceramic substrate and method of manufacturing the same {MULTILAYER CERAMIC SUBSTRATE, AND METHOD FOR MANUFACTURING THE SAME}

The present invention relates to a method of manufacturing a multilayer ceramic substrate including a molybdenum-copper metal composite electrode and having excellent mechanical strength and chemical resistance while having low resistance.

The reliability of the wafer on which a plurality of integrated circuit chips are formed through a wafer fabrication process is verified by electrical die sorting (EDS).

Testing equipment consisting of a tester, probe station, and probe card is usually used to inspect electrical properties. The probe card includes a space converter with multiple probe pins, a printed circuit board, a reinforcement plate, and an interposer. It is composed including.

The tester generates inspection signals and reads inspection result data. The probe station is responsible for loading and unloading the wafer, allowing the tester to perform its function, and the probe card performs the function of electrically connecting the wafer and the tester.

As the degree of integration of semiconductor integrated circuit devices increases, inspection devices that perform inspection processes for semiconductor integrated circuits also require high precision.

For example, in order to meet the inspection process for highly integrated semiconductor integrated circuit chips, fine pitch of probe pins connected to the semiconductor integrated circuit chips must be implemented.

For this purpose, a so-called space transformer (STF) is used, which compensates for the difference between the pitch of the probes and the pitch of the semiconductor integrated circuit.

In particular, the use of space converters made of ceramic is increasing because they have a thermal expansion coefficient similar to that of a silicon wafer and have excellent mechanical strength and chemical resistance.

However, the HTCC method has the disadvantage of having to use electrode materials with high resistance, such as molybdenum and tungsten, because it is fired at a high temperature of over 1,500°C.

On the other hand, a multilayer ceramic substrate manufactured using the LTCC method can use silver or copper electrodes with low resistance. Recently, the need for various circuit designs and heat dissipation designs using low-resistance characteristics has been highlighted.

However, the LTCC method has a problem of insufficient reliability due to lack of mechanical strength and chemical resistance due to the substrate material.

Therefore, there is a need to develop electrode materials that can be applied at higher firing temperatures and have low resistance.

The present invention is intended to solve the above-mentioned problems, and the purpose of the present invention is to provide a multilayer ceramic substrate including a molybdenum-copper metal composite electrode that is applicable to high firing temperatures and has low resistance.

According to one aspect of the invention, one or more ceramic layers; and an electrode formed on at least a portion of the ceramic layer, wherein the electrode includes a metal composite in which a copper layer is formed on at least a portion of the surface of the molybdenum particles. A multilayer ceramic substrate is provided.

In one embodiment, the metal composite may be fired at 1,300°C or higher.

In one embodiment, the metal composite may have a weight ratio of molybdenum and copper of 50 to 90:10 to 50, respectively.

In one embodiment, the metal composite may have a resistivity of 2.5 to 5.0×10 ^-6 Ω·cm at 20°C.

In one embodiment, at least one ceramic layer may include one or more through holes.

In one embodiment, the ceramic layer may be obtained by firing a ceramic composition containing 20 to 50% by weight of cordierite, 10 to 60% by weight of mullite, and 10 to 60% by weight of alumina.

According to another aspect of the present invention, manufacturing spherical copper powder by condensing copper powder after gas phase conversion; Pasteing the spherical copper powder and molybdenum powder and printing the spherical copper powder and molybdenum powder on at least one ceramic green sheet; A method for manufacturing a multilayer ceramic substrate is provided, including the step of laminating and firing one or more ceramic green sheets.

In one embodiment, the gas phase transformation may be performed by a plasma heat source.

In one embodiment, the weight ratio of the molybdenum and the copper may be 50 to 90:10 to 50, respectively.

In one embodiment, the firing may be performed at a temperature of 1,300°C or higher.

According to the present invention, it is possible to provide a multilayer ceramic substrate including a molybdenum-copper metal composite electrode that can be applied to a high temperature firing process and has low resistance.

Therefore, low resistance characteristics can be realized while using a highly reliable ceramic material with excellent mechanical strength and chemical resistance.

The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the configuration of the invention described in the detailed description or claims of the present invention.

Figure 1 shows an SEM image of an electrode included in a multilayer ceramic substrate according to an embodiment of the present invention.
Figure 2 shows an SEM image of an electrode included in a multilayer ceramic substrate according to another embodiment of the present invention.

The terms used in this specification are general terms that are currently widely used as much as possible while considering the function in the present invention, but this may vary depending on the intention or precedent of a person skilled in the art, the emergence of new technology, etc. In addition, in certain cases, there are terms arbitrarily selected by the applicant, and in this case, the meaning will be described in detail in the description of the relevant invention. Therefore, the terms used in the present invention should be defined based on the meaning of the term and the overall content of the present invention, rather than simply the name of the term.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and unless clearly defined in the present application, should not be interpreted in an ideal or excessively formal sense. No.

The numerical range includes the values defined in the range above. Every maximum numerical limit given throughout this specification includes all lower numerical limits as if the lower numerical limit were explicitly written out. Every minimum numerical limit given throughout this specification includes every higher numerical limit as if such higher numerical limit was clearly written. All numerical limits given throughout this specification will include all better numerical ranges within the broader numerical range, as if the narrower numerical limits were clearly written.

Hereinafter, examples of the present invention will be described in detail, but it is obvious that the present invention is not limited to the following examples.

Multilayer ceramic substrate

One aspect of the invention is one or more ceramic layers; and an electrode formed on at least a portion of the ceramic layer, wherein the electrode includes a metal composite in which a copper layer is formed on at least a portion of the surface of the molybdenum particles.

A multilayer ceramic board is a type of three-dimensional circuit board in which one or more ceramic layers are stacked. These multilayer ceramic substrates can be applied to various products such as wireless transmission/reception modules, sensors, photoelectric housings, multi-chip devices, LED mounting substrates, semiconductor packaging substrates, and space converters for probe cards.

Each ceramic layer may be a thick film formed by molding a ceramic composition into a predetermined plate shape. This ceramic composition may be formed by mixing at least one ceramic powder and an organic material. Ceramic powder can be synthesized to have specific properties by calcining a plurality of raw materials containing each composition component (or element).

Examples of such ceramic powders include cordierite, mullite, zirconia, and alumina. The ceramic composition may further include additives (or sintering aids) to increase sintering density.

Cordierite is a compound (2MgO-2Al ₂ O ₃ -5SiO ₂ ) with a sintering temperature of 1,200 to 1,300°C. It has a low thermal expansion coefficient of about 0.3 ppm/°C at 200°C and a flexural strength of about 100 MPa. Cordierite melts when fired at a high temperature of 1,300°C or higher and can act as a sintering aid.

Mullite is an alumina-silica-based compound (3Al ₂ O ₃ -2SiO ₂ ) with a sintering temperature of 1,500 to 1,600°C and has a flexural strength of about 250 MPa. Mullite exists as a stable intermediate phase even at high temperatures and has excellent thermal and chemical stability and heat resistance.

Alumina is an oxide of aluminum (Al ₂ O ₃ ) with a sintering temperature of 1,400 to 1,600°C, and has a thermal conductivity of about 11 W/m·K and a flexural strength of about 300 MPa.

Examples of additives include MgO, Y ₂ O ₃ , TiO ₂ , CaO, Cr ₂ O ₃ , V ₂ O ₅ , etc. By including these additives, the sintering temperature of the ceramic composition can be adjusted or the properties of the ceramic substrate can be controlled.

The ceramic composition can be mixed with an organic solvent such as water or ethanol and used in the form of a ceramic slurry. Ceramic slurry can be mixed by conventional methods such as ball milling or basket milling.

The mixed ceramic slurry can be dried to remove the liquid medium by various methods. A ceramic molded body can be formed by adding and mixing organic substances such as PVA (polyvinyl alcohol), PVB (polyvinyl butyral), and MC (methyl cellulose) as binders to the ceramic slurry from which the liquid medium has been removed.

The ceramic molded body may be molded into a plate shape and then sintered at a high temperature of 1,000°C to 2,000°C to be used as a ceramic green sheet that constitutes a multilayer ceramic substrate.

Each ceramic green sheet may be filled with a conductive material after punching through holes to form vias for inter-layer electrical conduction, or an electrode circuit pattern may be printed. A multilayer ceramic substrate can be manufactured by stacking a plurality of ceramic green sheets and firing them simultaneously.

Accordingly, the multilayer ceramic substrate includes one or more ceramic layers formed from ceramic green sheets, and at least some of these ceramic layers may include electrodes. These electrodes may be formed through printing on at least a portion of one side or the other side of the ceramic layer, or may be formed by injecting a conductive material into a through hole of the ceramic layer.

The number of ceramic layers is not particularly limited, and 10 to 100 layers may be stacked depending on the degree of integration of the semiconductor circuit pattern implemented on the semiconductor wafer.

Multilayer ceramic substrates are classified into High Temperature Co-fired Ceramic (HTCC) substrates or Low Temperature Co-fired Ceramic (LTCC) substrates depending on the firing temperature.

HTCC substrates are generally sintered at temperatures above 1,500°C, so ceramic powders with high sintering temperatures such as alumina and mullite are used. HTCC substrates have excellent flexural strength, chemical resistance, and high-frequency dielectric loss characteristics, but because sintering is performed at a temperature higher than the melting point of materials with low resistivity such as silver (962℃) and copper (1,084℃), molybdenum (molybdenum) with high resistivity is used. 2,623℃), tungsten (3,422℃), etc. should be used as electrode materials, and the thermal conductivity of the substrate is high.

LTCC substrates are generally fired at temperatures below 1,000°C, so glass and ceramic fillers are used. The dielectric constant of the LTCC substrate is easy to control, and materials with low resistivity such as silver and copper can be used as electrode materials, but its flexural strength and chemical resistance are insufficient compared to HTCC.

As an example, when manufacturing a space converter for a probe card, usable substrates are classified depending on the method of attaching the MEMS probe pin.

When forming a bumper pad using a semiconductor process and then attaching the MEMS probe pin by heat sealing, or forming a 3D MEMS probe pin on a ceramic substrate, a strong alkaline solution must be treated, so an HTCC substrate with excellent chemical resistance must be used. .

On the other hand, the laser adhesion method, which attaches MEMS probe pins individually after two-dimensional formation, has the problem of reduced adhesion when applied to HTCC substrates with high thermal conductivity, so it is mainly used on LTCC substrates.

According to one embodiment, a ceramic composition containing cordierite, mullite, and alumina may have a sintering temperature of 1,300 to 1,500°C. A ceramic layer manufactured from this ceramic composition can harmoniously implement the advantages of the above-described HTCC substrate and LTCC substrate.

The electrode of the multilayer ceramic substrate according to one aspect of the present invention may include a core-shell type metal composite in which a copper layer is formed on at least a portion of the surface of the molybdenum particles.

According to the phase equilibrium diagram of molybdenum-copper, when molybdenum and copper are simply mixed and the temperature is increased, copper exists in a liquid phase at a temperature of 1,084°C or higher. For this reason, when forming an electrode containing copper through firing at a temperature of 1,300°C or higher, there is a problem in that the copper is volatilized and the electrode circuit pattern is destroyed.

However, the metal composite according to one aspect of the present invention can form an electrode with low specific resistance even when fired at a temperature of 1,300°C or higher using copper treated through a specific process.

In one embodiment, the electrode may be formed by baking a conductive paste in which spherical copper particles and molybdenum particles are dispersed in a solvent.

Conductive paste is a material that disperses conductive fillers and binders in a solvent and is an essential material for the manufacture of printed electronic devices.

Conductive fillers used in common conductive pastes include metal powders such as gold, silver, copper, nickel, and aluminum.

Silver paste made by dispersing silver powder in a solvent or copper paste made by dispersing copper powder in a solvent has low resistance and excellent conductivity, but it is difficult to maintain the circuit pattern during high temperature firing due to their low melting points of 962℃ and 1,084℃, respectively. Alternatively, there is a problem of it being lost due to volatilization.

On the other hand, pastes using metal materials such as molybdenum and tungsten have high melting points of 2,623°C and 3,422°C, so they can be easily applied to high-temperature firing processes, but have the disadvantage of having a high resistivity of the material itself.

The electrode according to one aspect of the present invention is manufactured by dispersing spherical copper particles and molybdenum particles in a solvent, so that it can be applied to a high temperature sintering process and have low specific resistance.

Here, the spherical copper particles may be manufactured by rapidly cooling molten or evaporated copper using a plasma heat source. Although the exact mechanism of action is not known, mixing these spherical copper particles with molybdenum particles can improve the problem of copper volatilizing when fired at a high temperature above the melting point of copper.

The conductive paste in which spherical copper particles and molybdenum particles are dispersed goes through a sintering process to form a core-shell metal composite in which a copper shell is formed on at least a portion of the surface of the molybdenum core.

That is, the metal complex is heated above 1,300°C, for example, 1,300°C, 1,305°C, 1,310°C, 1,315°C, 1,320°C, 1,325°C, 1,330°C, 1,335°C, 1,340°C, 1,345°C, 1,350°C, 1,355°C, 1,360℃, 1,365℃, 1,370℃, 1,375℃, 1,380℃, 1,385℃, 1,390℃, 1,395℃, 1,400℃, 1,405℃, 1,410℃, 1,415℃, 1,420℃, 1,425℃, 1,430℃, 1,4 35℃, 1,440℃ , 1,445°C, 1,450°C, or a temperature range between the two values may have low resistivity.

In this metal complex, the weight ratio of molybdenum and copper may be 50 to 90:10 to 50, respectively. For example, the weight ratio of molybdenum to copper is 50:50, 55:45, 60:40, 65:35, 70:30, 75:25, 80:20, 85:15, 90:10, or two of these values. It may be in the range between, but is not limited to this. If the ratio of molybdenum is too small, high temperature sintering may be difficult, and if the ratio of molybdenum is too high, the specific resistance of the electrode circuit layer may increase.

The metal composite has a resistivity at 20°C of 2.5 to 5.0×10 ^-6 Ω·cm, for example, 2.5×10 ^-6 Ω·cm, 2.6×10 ^-6 Ω·cm, 2.7×10 ^-6 Ω·cm, 2.8×10 ^-6 Ω·cm, 2.9×10 ^-6 Ω·cm, 3.0×10 ^-6 Ω·cm, 3.1×10 ^-6 Ω·cm, 3.2×10 ^-6 Ω·cm, 3.3×10 ^-6 Ω·cm, 3.4×10 ^-6 Ω·cm, 3.5×10 ^-6 Ω·cm, 3.6×10 ^-6 Ω·cm, 3.7×10 ^-6 Ω·cm, 3.8×10 ^-6 Ω·cm, 3.9 ×10 ^-6 Ω·cm, 4.0×10 ^-6 Ω·cm, 4.1×10 ^-6 Ω·cm, 4.2×10 ^-6 Ω·cm, 4.3×10 ^-6 Ω·cm, 4.4×10 ^-6 Ω ·cm, 4.5×10 ^-6 Ω·cm, 4.6×10 ^-6 Ω·cm, 4.7×10 ^-6 Ω·cm, 4.8×10 ^-6 Ω·cm, 4.9×10 ^-6 Ω·cm, 5.0× It may be 10 ^-6 Ω·cm or a range between these two values. The resistivity of the metal composite may vary depending on the ratio of molybdenum and copper or the sintering process, but may have a lower value than the resistivity of molybdenum.

Each ceramic layer included in the multilayer ceramic substrate is a dielectric material and can electrically insulate electrodes formed on different ceramic layers or electrodes formed on one side and the other side of one ceramic layer.

However, at least one ceramic layer may include one or more through holes. These through holes are also called through holes or via holes, and can electrically connect electrodes located on one side of the ceramic layer to electrodes located on the other side. In one example, such a through hole may be formed through several ceramic layers.

The through hole may have a conductive layer formed on its inner wall, or may include an electrode filled with a conductive material or a non-conductive material. Through this type of electrode, through-holes can make electrical connections between different electrodes insulated with a ceramic layer.

Among through holes, those for mounting electronic components are called through holes, and those for interlayer connection without mounting separate components are called via holes. A via hole filled with a conductive material can be called a via fill.

That is, the multilayer ceramic substrate according to one aspect of the present invention is a molybdenum-copper metal composite in which at least some of the electrodes including the electrode circuit layer, through holes, via holes, via fills, etc. formed on the surface of the ceramic layer include spherical copper particles. may include.

In a non-limiting example of the present invention, the ceramic layer may be a fired ceramic composition containing 20 to 50% by weight of cordierite, 10 to 60% by weight of mullite, and 10 to 60% by weight of alumina, but is limited thereto. That is not the case. If the ceramic composition has the above-described composition, it can have a sintering temperature of 1,300 to 1,500°C.

The ceramic composition contains 20 to 50% by weight of cordierite, for example, 20% by weight, 22.5% by weight, 25% by weight, 27.5% by weight, 30% by weight, 32.5% by weight, 35% by weight, 37.5% by weight. , 40% by weight, 42.5% by weight, 45% by weight, 47.5% by weight, 50% by weight, or a range between any two of these values. If the content of cordierite in the ceramic composition is too small, the strength of the ceramic layer may decrease. If the content of cordierite in the ceramic composition is too high, the shrinkage rate of the ceramic layer may increase during firing.

The ceramic composition contains 10 to 60% by weight of mullite, for example, 10% by weight, 12.5% by weight, 15% by weight, 17.5% by weight, 20% by weight, 22.5% by weight, 25% by weight, 27.5% by weight, 30% by weight. %, 32.5% by weight, 35% by weight, 37.5% by weight, 40% by weight, 42.5% by weight, 45% by weight, 47.5% by weight, 50% by weight, 52.5% by weight, 55% by weight, 57.5% by weight, 60% by weight Or it may be a range between two of these values. If the content of mullite in the ceramic composition is too small, the thermal expansion coefficient of the ceramic layer may increase. If the content of mullite in the ceramic composition is too high, the sintering temperature may increase.

The ceramic composition contains 10 to 60% by weight of alumina, for example, 10% by weight, 12.5% by weight, 15% by weight, 17.5% by weight, 20% by weight, 22.5% by weight, 25% by weight, 27.5% by weight, 30% by weight. %, 32.5% by weight, 35% by weight, 37.5% by weight, 40% by weight, 42.5% by weight, 45% by weight, 47.5% by weight, 50% by weight, 52.5% by weight, 55% by weight, 57.5% by weight, 60% by weight Or it may be a range between two of these values. If the alumina content in the ceramic composition is too small, the substrate strength of the ceramic layer may be lowered. If the alumina content in the ceramic composition is too high, the coefficient of thermal expansion may increase.

Manufacturing method of multilayer ceramic substrate

Another aspect of the present invention includes manufacturing spherical copper powder by condensing copper powder after gas phase conversion; Pasteing the spherical copper powder and molybdenum powder and printing the spherical copper powder and molybdenum powder on at least one ceramic green sheet; and the step of laminating and firing one or more ceramic green sheets.

When spherical copper powder prepared by condensing copper powder after gas phase conversion is mixed with molybdenum powder, a molybdenum-copper metal complex with low resistivity can be formed even when fired at a temperature above 1,084°C, which is the melting point of copper. The characteristics of the metal composite are as described above.

Gas phase conversion of copper powder can be performed by a plasma heat source. For example, spherical copper powder can be manufactured by rapidly converting the vapor phase using plasma arc vapor discharge, plasma atomization, etc. and then cooling it.

The manufactured spherical copper powder can be converted into a conductive paste form by mixing it with molybdenum powder, a binder, a solvent, etc. Here, the ratio of copper and molybdenum and conditions during firing are the same as described above.

At least one ceramic green sheet may include one or more through holes. The characteristics of the through hole of the ceramic green sheet can be referred to as those of the through hole of the ceramic layer described above.

A conductive paste containing spherical copper powder may be applied to the surface of at least one ceramic green sheet or to the through hole of at least one ceramic green sheet to form an internal electrode of the multilayer ceramic substrate.

A multilayer ceramic substrate having the above-described characteristics may satisfy at least one of the physical properties (i) to (v) below: (i) shrinkage rate of 20% or less; (ii) thermal expansion coefficient of 5 ppm/℃ or less; (iii) thermal conductivity of 3 to 5 W/m·K, (iv) dielectric constant of 6.5 to 8, (v) flexural strength of 200 MPa or more.

For example, the multilayer ceramic substrate has a shrinkage rate of 20% or less by volume before and after firing, for example, 20%, 19.8%, 19.6%, 19.4%, 19.2%, 19%, 18.8%, 18.6%, 18.4%, 18.2%. , 18%, 17.8%, 17.6%, 17.4%, 17.2%, 17%, 16.8%, 16.6%, 16.4%, 16.2%, 16%, 15.8%, 15.6%, 15.4%, 15.2%, 15% or these It can fall in the range between two values.

As another example, the multilayer ceramic substrate is heated from room temperature (25°C) to 150°C and the measured thermal expansion coefficient is 5 ppm/°C or less, for example, 5 ppm/°C, 4.95 ppm/°C, 4.9 ppm/°C, 4.85 ppm. /℃, 4.8 ppm/℃, 4.75 ppm/℃, 4.7 ppm/℃, 4.65 ppm/℃, 4.6 ppm/℃, 4.55 ppm/℃, 4.5 ppm/℃, 4.45 ppm/℃, 4.4 ppm/℃, 4.35 ppm /℃, 4.3 ppm/℃, 4.25 ppm/℃, 4.2 ppm/℃, 4.15 ppm/℃, 4.1 ppm/℃, 4.05 ppm/℃, 4 ppm/℃, 3.95 ppm/℃, 3.9 ppm/℃, 3.85 ppm /°C, 3.8 ppm/°C, 3.75 ppm/°C, 3.7 ppm/°C, 3.65 ppm/°C, 3.6 ppm/°C, 3.55 ppm/°C, 3.5 ppm/°C, or a range between any two of these values.

As another example, the multilayer ceramic substrate has a thermal conductivity of 3 to 5 W/m·K, for example, 3 W/m·K, 3.05 W/m·K, 3.1 W/m·K, 3.15 W/m·K. , 3.2 W/m·K, 3.25 W/m·K, 3.3 W/m·K, 3.35 W/m·K, 3.4 W/m·K, 3.45 W/m·K, 3.5 W/m·K, 3.55 W/m·K, 3.6 W/m·K, 3.65 W/m·K, 3.7 W/m·K, 3.75 W/m·K, 3.8 W/m·K, 3.85 W/m·K, 3.9 W/m·K, 3.95 W/m·K, 4 W/m·K, 4.05 W/m·K, 4.1 W/m·K, 4.15 W/m·K, 4.2 W/m·K, 4.25 W /m·K, 4.3 W/m·K, 4.35 W/m·K, 4.4 W/m·K, 4.45 W/m·K, 4.5 W/m·K, 4.55 W/m·K, 4.6 W/ m·K, 4.65 W/m·K, 4.7 W/m·K, 4.75 W/m·K, 4.8 W/m·K, 4.85 W/m·K, 4.9 W/m·K, 4.95 W/m ·K, 5 W/m·K, or the range between these two values can be satisfied.

As another example, the multilayer ceramic substrate has a dielectric constant measured at a frequency of 1 MHz of 6.5 to 8, for example, 6.5, 6.55, 6.6, 6.65, 6.7, 6.75, 6.8, 6.85, 6.9, 6.95, 7, 7.05, 7.1, It can be 7.15, 7.2, 7.25, 7.3, 7.35, 7.4, 7.45, 7.5, 7.55, 7.6, 7.65, 7.7, 7.75, 7.8, 7.85, 7.9, 7.95, 8, or a range between any two of these values.

In another example, the flexural strength of the multilayer ceramic substrate is 200 MPa or more, for example, 200 MPa, 205 MPa, 210 MPa, 215 MPa, 220 MPa, 225 MPa, 230 MPa, 235 MPa, 240 MPa, 245 MPa, 250 MPa. MPa, 255 MPa, 260 MPa, 265 MPa, 270 MPa, 275 MPa, 280 MPa, 285 MPa, 290 MPa, 295 MPa, 300 MPa, 305 MPa, 310 MPa, 315 MPa, 320 MPa, 325 MPa, 330 MPa, It may be 335 MPa, 340 MPa, 345 MPa, 350 MPa, or a range between these two values.

However, these physical properties are one of the various properties that can be realized depending on the purpose of use of the above-mentioned multilayer ceramic substrate, and all of these physical properties do not have to be satisfied.

The present invention will be described in further detail through the following examples, but it is obvious that the present invention is not limited by the following examples.

Example 1

Copper powder was evaporated using an arc plasma combustion device and then rapidly cooled to produce spherical copper powder. The arc plasma combustion device was adjusted to spray plasma with a temperature of 20,000 K at the center and 11,000 K at the outside to an area of 10 mm in distance and 10 mm in diameter.

The evaporated copper was passed through a water-cooled cooling device to obtain the form of spherical copper powder. The arc plasma combustion device supplied nitrogen to the crucible at a flow rate of 5 to 30 l/min and generated plasma with a power of 50 to 150 V and 150 to 450 A to melt and evaporate copper.

A conductive paste was prepared by uniformly dispersing spherical copper powder and molybdenum powder in a mixed solution of ethylcellulose dissolved in alpha-terpineol.

Example 2

A conductive paste was prepared in the same manner as in Example 1, except that spherical copper powder and molybdenum powder were uniformly dispersed in a mixed solution of polystyrene sulfonate dissolved in distilled water.

Example 3

A conductive paste was manufactured in the same manner as in Example 1, except that spherical copper powder was manufactured using a plasma atomization process of melting a copper wire with a plasma gun in an arc plasma combustion device.

Comparative Example 1

A conductive paste was prepared in the same manner as Example 1, except that copper powder was used instead of spherical copper powder.

Comparative Example 2

A conductive paste was prepared in the same manner as Example 1, except that copper powder was used alone, except for molybdenum powder.

Comparative Example 3

A conductive paste was prepared in the same manner as Example 1, except that molybdenum powder was used alone, except for the spherical copper powder.

Manufacturing example

A ceramic green sheet was manufactured using a ceramic composition having the composition ratio shown in Table 1 below as the main component.

division cordier light mullite alumina Manufacturing example 1 50 25 25 Production example 2 30 45 25 Production example 3 35 40 25 Production example 4 40 35 25 Production example 5 30 25 45 Production example 6 30 35 35 Production example 7 20 50 30 Production example 8 20 30 50 Production example 9 30 60 10 Production example 10 30 10 60

Experimental Example 1: Evaluation of electrode characteristics

An electrode pattern was formed on the ceramic green sheet of Preparation Example 9 using the conductive paste of Examples and Comparative Examples, and then a plurality of ceramic green sheets were stacked and fired at a temperature of 1,450°C to prepare a multilayer ceramic substrate.

The electrode characteristics of the manufactured multilayer ceramic substrate are shown in Table 2 below. Scanning electron microscope (SEM) photographs of the metal composite forming the electrode of Example 1 are shown in Figures 1 and 2.

division electrode material Specific resistance (20℃) Example 1-1 80Mo-20Cu (old) 3.5×10 ^-6 Ω·cm Example 1-2 70Mo-30Cu (old) 3.3×10 ^-6 Ω·cm Example 1-3 50Mo-50Cu (spherical) 2.9×10 ^-6 Ω·cm Example 2 70Mo-30Cu (old) 3.4×10 ^-6 Ω·cm Example 3 60Mo-40Cu (old) 3.1×10 ^-6 Ω·cm Comparative Example 1 80Mo-20Cu 6.9×10 ^-6 Ω·cm Comparative Example 2 Cu - Comparative Example 3 Mo 7.0×10 ^-6 Ω·cm

Referring to Table 2, it can be seen that the electrodes of Examples 1 to 3 have a lower specific resistance compared to the molybdenum electrode.

Referring to Figure 1, it can be seen that the electrode exists as a core-shell metal composite in which a copper layer is formed on the surface of the molybdenum particles.

Referring to Figure 2, it can be seen that the copper layer formed on the surface of the molybdenum particles in the electrode to which spherical copper powder was applied formed a kind of network structure.

On the other hand, it can be confirmed that the electrode of Comparative Example 1, in which ordinary copper powder rather than plasma-treated spherical copper powder was applied, had characteristics similar to molybdenum due to the volatilization of copper.

In Comparative Example 2, an electrode was not formed as the copper powder was melted and volatilized at high temperature.

These results suggest that molybdenum-copper metal composite can be applied as an electrode material with low specific resistance at high temperatures above 1,300°C.

Experimental Example 2: Evaluation of ceramic substrate properties

The mechanical properties of the ceramic substrate manufactured through the manufacturing example were evaluated and are shown in Table 3 below.

division firing temperature shrinkage rate
(%) thermal expansion coefficient
(ppm/℃)
Room temperature~150℃ thermal conductivity
(W/m·K) permittivity
(Measurement frequency 1MHz) Flexural strength
(MPa) Manufacturing Example 1 1,350 17.3 3.27 4.54 6.92 243 Production example 2 1,450 16.3 3.84 4.87 6.74 258 Production example 3 1,450 16.1 3.98 4.75 6.85 253 Production example 4 1,400 16.1 3.96 4.79 6.58 248 Production example 5 1,450 16.0 4.12 4.63 6.97 249 Production example 6 1,450 16.0 3.92 4.88 7.14 245 Production example 7 1,450 15.8 3.37 4.76 6.72 214 Production example 8 1,450 15.8 3.69 4.64 6.54 220 Production example 9 1,450 15.4 3.14 4.86 6.88 251 Production example 10 1,450 15.7 3.92 4.92 7.12 252

The description of the present invention described above is for illustrative purposes, and those skilled in the art will understand that the present invention can be easily modified into other specific forms without changing the technical idea or essential features of the present invention. will be.

Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive. For example, each component described as a single type may be implemented in a dispersed form, and similarly, components described as distributed may also be implemented in a combined form. The scope of the present invention is defined by the patent claims described later. It is indicated by, and the meaning and scope of the patent claims and all changes or modified forms derived from the equivalent concept should be construed as being included in the scope of the present invention.

Claims (10)

one or more ceramic layers; and
Includes an electrode formed on at least a portion of the ceramic layer,
The electrode is a multilayer ceramic substrate comprising a metal composite in which a copper layer is formed on at least a portion of the molybdenum particle surface. According to paragraph 1,
The metal composite is a multilayer ceramic substrate fired at 1,300°C or higher. According to paragraph 1,
The metal composite is a multilayer ceramic substrate in which the weight ratio of molybdenum and copper is 50 to 90:10 to 50, respectively. According to paragraph 1,
The metal composite is a multilayer ceramic substrate having a resistivity of 2.5 to 5.0×10 ^-6 Ω·cm at 20°C. According to paragraph 1,
At least one ceramic layer includes one or more through holes. According to paragraph 1,
The ceramic layer is a multilayer ceramic substrate in which a ceramic composition containing 20 to 50% by weight of cordierite, 10 to 60% by weight of mullite, and 10 to 60% by weight of alumina is fired. Condensing copper powder after gas phase conversion to produce spherical copper powder;
Pasteing the spherical copper powder and molybdenum powder and printing the spherical copper powder and molybdenum powder on at least one ceramic green sheet; and
A method of manufacturing a multilayer ceramic substrate, comprising the step of laminating and firing one or more ceramic green sheets. In clause 7,
A method of manufacturing a multilayer ceramic substrate, wherein the gas phase conversion is performed by a plasma heat source. In clause 7,
A method of manufacturing a multilayer ceramic substrate, wherein the weight ratio of the molybdenum and the copper is 50 to 90:10 to 50, respectively. In clause 7,
A method of manufacturing a multilayer ceramic substrate, wherein the firing is performed at a temperature of 1,300°C or higher.