阅读说明：本技术 陶瓷层与铜粉糊烧结体的积层体 (Laminate of ceramic layer and copper powder paste sintered body ) 是由 古泽秀树 于 2019-07-25 设计创作，主要内容包括：本发明涉及一种陶瓷层与铜粉糊烧结体的积层体。具体地,提供一种积层体,其是通过铜粉糊的烧结所制造的烧结体与陶瓷基材的积层体,且烧成体与陶瓷基材的密接性优异。本发明的积层体在陶瓷层积层有铜粉糊烧结体,且在铜粉糊烧结体中,根据EBSD图像所求出的利用面积分数法(Area Fraction Method)获得的铜的结晶粒径为10μm以下,且分析区域的平均可靠性指数(CI值)为0.5以上。(The present invention relates to a laminate of a ceramic layer and a sintered copper powder paste. Specifically disclosed is a laminate of a sintered body produced by sintering a copper powder paste and a ceramic base material, which is excellent in adhesion between the sintered body and the ceramic base material. The laminate of the present invention comprises a copper powder paste sintered body laminated on a ceramic layer, wherein the copper powder paste sintered body has a crystal grain size of copper obtained by an Area Fraction Method (Area Fraction Method) determined from an EBSD image of 10[ mu ] m or less and an average reliability index (CI value) in an analysis region of 0.5 or more.)

1. A laminate comprising a non-metallic laminate layer and a sintered copper powder paste

In the copper powder paste sintered body, the grain size of copper obtained by an Area Fraction Method (Area Fraction Method) determined from an EBSD image is 10[ mu ] m or less, and the average reliability index (CI value) in an analysis region is 0.5 or more.

2. The laminate according to claim 1, wherein the copper powder paste sintered body contains ceramic particles in grain boundaries or crystal grains.

3. The laminate according to claim 2, wherein the maximum particle diameter of the ceramic particles is 100nm or less.

4. The laminate according to claim 3, wherein the non-metal layer is a layer containing at least 1 of a ceramic, a Si wafer, and a resin film.

5. The laminate according to claim 4, wherein the non-metallic layer is a ceramic layer.

6. The laminate according to claim 1, wherein the crystal grain size of copper obtained by an area fraction method as determined from an EBSD image is 1 μm or more and 10 μm or less.

7. The laminate as claimed in claim 1, wherein the sintered body of copper powder paste is a sintered body of copper powder paste containing no glass frit.

8. The laminate as claimed in claim 1, wherein the copper powder paste sintered body has a specific surface area of 1m²g^-1The above sintered body of copper powder paste.

9. The laminate according to claim 1, wherein the non-metal layer is an aluminum oxide layer, a layer containing barium titanate as a main component, a sintered body layer of CuNiZn ferrite particles, an aluminum nitride layer or a silicon nitride layer.

10. The laminate according to claim 1, wherein the non-metal layer is a ceramic layer, and an element having the highest atomic concentration among elements other than O in the ceramic of the ceramic layer is Si, and a next highest element is Al.

11. A copper-ceramic composite body comprising the laminate body of any one of claims 1 to 10.

12. An electronic part having the laminate as defined in any one of claims 1 to 10.

Technical Field

The present invention relates to a laminate of a ceramic layer and a sintered copper powder paste.

Background

As the frequency band of use of electronic devices shifts to the high frequency side, demand for a multilayer component using ceramics as an insulating substrate is increasing. MLCC in the case of a capacitor and LTCC in the case of a substrate. As the electrode material, nickel powder for internal electrodes and copper powder for external electrodes are used or studied for the former, and silver powder or copper powder is used or studied for the latter. Copper powder is cheaper than silver powder and is more advantageous than nickel from the viewpoint of electrical resistance, so copper powder has been attracting attention as an electrode material.

Metal powder as an electrode material is mixed with a solvent, a binder resin, and the like to be processed into paste, and the paste is printed on a ceramic substrate or a green sheet made of ceramic particles. The laminate is fired in a non-oxidizing atmosphere or a reducing atmosphere at 600 ℃ or higher, for example, to sinter the metal powders, thereby obtaining an electrode. The thermal expansion coefficient of metal is large relative to the ceramic of the substrate, and there is a case where the fired electrode is peeled from the ceramic substrate due to a difference in expansion and contraction during firing. In order to avoid this, ceramic particles constituting the ceramic layer, or glass frit (glass frit) particles, are added to the metal paste to secure the adhesion force between the fired electrode and the ceramic substrate.

In the MLCC, the size of the components is limited, but if the number of layers can be increased, the capacitance of each component can be increased, and therefore, in order to realize this, it is necessary to thin the electrode paste. In addition, in the case of LTCC, since the mounting density of the substrate can be increased as long as the circuit width can be narrowed, it is advantageous that the printing can be performed at a narrow pitch without breaking. In order to meet such a demand, attempts have been made to improve metal powder pastes and metal powders used for the metal powder pastes (patent documents 1 and 2).

[ Prior art documents ]

[ patent document ]

[ patent document 1] International publication No. 2013/125659

[ patent document 2] International publication No. 2013/118893

Disclosure of Invention

[ problems to be solved by the invention ]

As described above, the sintered electrode (sintered body) is produced by sintering a paste of metal powder such as copper powder. On the other hand, in the case of using a composite of the fired body and a ceramic substrate in a wide temperature range for use in a vehicle, etc., the number of cases is increasing. Therefore, the fired body is required to have strong adhesion to the ceramic substrate so that the fired body and the ceramic substrate do not peel off even in the wide temperature range.

Accordingly, an object of the present invention is to provide a laminate of a sintered body produced by sintering a copper powder paste and a ceramic base material, which is excellent in adhesion between the sintered body and the ceramic base material.

[ means for solving the problems ]

The present inventors have conducted extensive studies and, as a result, have found that the above object can be achieved by a composite described below, and have completed the present invention.

Accordingly, the present invention includes the following (1).

(1)

A laminate comprising a non-metallic laminate layer and a sintered copper powder paste

In the copper powder paste sintered body, the crystal grain size of copper obtained by an area fraction method (area fraction method) determined from an EBSD image is 10[ mu ] m or less, and the average reliability index (CI value) in an analysis region is 0.5 or more.

[ Effect of the invention ]

According to the present invention, a laminate of a sintered body produced by sintering a copper powder paste and a ceramic base material can be obtained, and the sintered body and the ceramic base material have excellent adhesion.

Drawings

FIG. 1 is a crystal orientation map (IPF map) of example 1.

FIG. 2 is a crystal orientation map (IPF map) of example 3.

Fig. 3 shows STEM observation and EDS analysis results of the vicinity of the grain boundary in example 3.

FIG. 4 is a crystal orientation map (IPF map) of comparative example 1.

Detailed Description

The present invention will be described in detail below with reference to embodiments. The present invention is not limited to the specific embodiments described below.

[ laminate having sintered copper powder paste in non-metallic laminate layer ]

The laminate of the present invention has a copper powder paste sintered body in a non-metal laminated layer, and in the copper powder paste sintered body, the crystal grain size of copper obtained by an area fraction method obtained from an EBSD image is 10[ mu ] m or less, and the average reliability index (CI value) in an analysis region is 0.5 or more.

In a preferred embodiment, a laminate having a sintered copper powder paste as a non-metal laminate layer comprises: a laminate comprising such a laminate structure. For example, the laminate includes a copper powder paste sintered body layer laminated on a non-metal layer and a non-metal layer laminated on the copper powder paste sintered body layer, and the laminate includes a laminate formed by repeatedly laminating them. The layer is a term for explaining the orientation of the build-up layer, and is not limited to the vertical direction.

In a preferred embodiment, the non-metallic layer can be provided as a ceramic layer. In the present specification, a ceramic layer may be specifically described as a suitable non-metal layer.

[ sintered copper powder paste ]

The laminate of the present invention can be produced by laminating a sintered copper powder paste on a non-metal layer, for example, a ceramic layer. The copper powder paste sintered body is prepared by sintering the coated copper powder paste.

In a preferred embodiment, the sintering for preparing the copper powder paste sintered body may be performed by a known method, and for example, the sintering may be performed by maintaining the temperature at 500 to 1000 ℃ for 0.1 to 10 hours in a non-oxidizing environment, a weakly reducing environment, or a steam environment.

Copper powder paste is applied to the surface of a non-metallic layer, such as a ceramic layer, prior to sintering. In a preferred embodiment, the coating can be performed by a known method, for example, screen printing or a dispensing method.

[ copper powder paste ]

The copper powder paste can be prepared using surface-treated copper powder by a known method. In a preferred embodiment, the surface-treated copper powder is prepared by kneading the surface-treated copper powder with a solvent, a binder resin, and known additives. In a preferred embodiment, a known solvent can be used as the solvent, and examples of such a solvent include: an alcohol solvent (e.g., 1 or more selected from the group consisting of terpineol, dihydroterpineol, isopropanol, butyl carbitol, terpinoxyethanol, and dihydroterpinoxyethanol), a glycol ether solvent (e.g., butyl carbitol), an acetate solvent (e.g., 1 or more selected from the group consisting of butyl carbitol acetate, dihydroterpineol acetate, dihydrocarbitol acetate, carbitol acetate, linalyl acetate, and terpinyl acetate), a ketone solvent (e.g., methyl ethyl ketone), a hydrocarbon solvent (e.g., 1 or more selected from the group consisting of toluene and cyclohexane), a cellosolve (e.g., 1 or more selected from the group consisting of ethyl cellosolve and butyl cellosolve), diethyl phthalate, or a propionate-based solvent (e.g., selected from the group consisting of dihydroterpinyl propionate, dihydrocaryl propionate), At least 1 of isobornyl propionate). In a preferred embodiment, a known binder resin can be used as the binder resin, and examples of such a binder resin include: cellulose-based resin, acrylic resin, alkyd resin, polyvinyl alcohol-based resin, polyvinyl acetal, ketone resin, urea resin, melamine resin, polyester, polyamide, and polyurethane (polyurethane).

In a preferred embodiment, as the copper powder paste, a paste to which no glass frit is added may be used.

[ surface-treated copper powder ]

The surface-treated copper powder is used to prepare a copper powder paste. In a preferred embodiment, the copper powder for surface treatment may be, for example, submicron copper powder, copper powder prepared by a wet method, copper powder prepared by a disproportionation method or a chemical reduction method, or the like. In a preferred embodiment, the surface treatment of the copper powder may be performed by mixing with a copper powder surface treatment agent solution, and for example, the copper powder surface treatment agents disclosed in patent document 1 (international publication No. 2013/125659) and patent document 2 (international publication No. 2013/118893) may be used according to the procedures disclosed in the above documents to perform the surface treatment.

In a suitable embodiment, the surface-treated copper powder may have a specific surface area of, for example, 1m²g^-1Above, preferably 2m²g^-1The above copper powder.

[ non-metallic layer ]

In a preferred embodiment, at least 1 type of layer including a ceramic, a Si wafer, and a film (e.g., a resin film) is used as the non-metal layer. In a preferred embodiment, a ceramic layer is used as the non-metallic layer.

[ ceramic layer ]

In a preferred embodiment, a ceramic substrate is used as the ceramic layer. As the ceramic of the ceramic substrate, known ceramics can be used, and examples of such ceramics include ceramics mainly composed of alumina and barium titanate, sintered ceramics of CuNiZn ferrite particles, ceramics containing aluminum nitride, silicon nitride, and CaZrO₃、CaTiO₃、HfO₂、BaTi₂O₅、(K,Na)NbO₃A ceramic of any one or more of. These ceramics can be prepared from known materials by known means, respectively.

In a preferred embodiment, as the ceramic, a ceramic in which the element having the highest atomic concentration among elements other than O (oxygen) is Si and the next highest element is Al may be used.

[ grain size of copper crystals and CI value obtained by area fraction method ]

In a preferred embodiment, the copper powder paste sintered body of the laminate has a crystal grain size of copper obtained by an area fraction method as determined from an EBSD image, which is, for example, 10 μm or less, preferably 5 μm or less, more preferably 3 μm or less, and is, for example, 0.5 μm or more, preferably 1 μm or more. The crystal grain size of copper obtained by the area fraction method can be specifically determined by the means described below in examples.

The crystal grain size of copper was measured by an area fraction method, and an average reliability index (CI value) indicating how much the crystal orientation can be identified in the analysis region was obtained. The average reliability index (CI value) can be specifically determined by the means described below in examples. In a preferred embodiment, the average reliability index (CI value) of the analysis region is, for example, 0.5 or more, preferably 0.55 or more, for example, in the range of 0.55 to 1.0.

The present inventors have found that: when the copper powder paste sintered body is used as an index, the layers laminated by the laminate exhibit excellent adhesion, and the result of the tape peeling test is good, and the copper powder paste sintered body has good specific resistance, thereby completing the present invention. The mechanism is not clear, but the present inventors speculate that: when such recrystallized grains are 10 μm or less and CI value is 0.5 or more, the strength of the fired body is high (Hall-Petch law) and the grains are uniform, so that strain is not easily locally accumulated, thereby achieving excellent adhesion. Further, the present inventors considered that: in order to bring the recrystallized grains to 10 μm or less and CI to 0.5 or more, it is effective to sufficiently disperse the surface-treated copper powder in the copper powder paste in the paste. More specifically, the present inventors considered that: if the dispersibility of the copper powder in the paste is poor, that is, if aggregates are present in the paste, irregularities are formed on the EBSD measurement surface of the fired copper, and the crystal orientation discrimination (CI value) is lowered.

[ ceramic particles in copper powder paste sintered body ]

In a preferred embodiment, in the copper powder paste sintered body, ceramic particles are present in the grain boundaries or crystal grains of copper. The particle size of the ceramic particles present can be, for example, 100nm or less at the maximum, preferably 50nm at the maximum. In a preferred embodiment, ceramic particles having an average particle diameter in the range of 0.1nm to 100nm, preferably 1nm to 50nm, may be present in the copper powder paste sintered body at grain boundaries or in the grains of copper.

[ specific resistance ]

In a preferred embodiment, the copper powder paste sintered body of the laminate in which the copper powder paste sintered bodies are laminated on the nonmetal layers exhibits excellent specific resistance. In a preferred embodiment, the concentration of the metal oxide is set to a range of, for example, 1.7 to 10[ mu ] Ω · cm ] or 1.8 to 3.4[ mu ] Ω · cm ]. The specific resistance can be measured by a known method.

[ peeling test ]

In a preferred embodiment, the laminate having the sintered copper powder paste in the non-metal laminate layer exhibits excellent characteristics, i.e., excellent adhesion, in a tape peeling test. The tape peel test can be performed according to the procedure of the examples described below.

[ preferred embodiments ]

In a preferred embodiment, the present invention also resides in the following (1) and (b).

(1)

A laminate comprising a non-metallic laminate layer and a sintered copper powder paste

In the copper powder paste sintered body, the grain size of copper obtained by an area fraction method obtained from an EBSD image is 10 μm or less, and the average reliability index (CI value) in an analysis region is 0.5 or more.

(2)

The laminate according to item (1), wherein the copper powder paste sintered body contains ceramic particles in grain boundaries or crystal grains.

(3)

The laminate according to item (2), wherein the maximum particle diameter of the ceramic particles is 100nm or less.

(4)

The laminate according to any one of (1) to (3), wherein the non-metal layer is a layer containing at least 1 of a ceramic, a Si wafer, and a film (e.g., a resin film).

(5)

The laminate as set forth in (4), wherein the non-metal layer is a ceramic layer.

(6)

The laminate according to any one of (1) to (5), wherein the crystal grain size of copper obtained by an area fraction method as determined from an EBSD image is 1 μm or more and 10 μm or less.

(7)

The laminate according to any one of (1) to (6), wherein the copper powder paste sintered body is a sintered body of copper powder paste containing no glass frit.

(8)

The laminate as set forth in any one of (1) to (7), wherein the copper powder paste sintered body has a specific surface area of 1m²g^-1The above sintered body of copper powder paste.

(9)

The laminate according to any one of (1) to (8), wherein the non-metal layer is an aluminum oxide layer, a layer containing barium titanate as a main component, a sintered body layer of CuNiZn ferrite particles, an aluminum nitride layer or a silicon nitride layer.

(10)

The laminate according to any one of (1) to (9), wherein the non-metal layer is a ceramic layer, and an element having the highest atomic concentration among elements other than O in the ceramic of the ceramic layer is Si, and the next highest element is Al.

(11)

A copper-ceramic composite body comprising the laminate of any one of (1) to (10).

(12)

An electronic part having the laminate of any one of (1) to (10).

The present invention includes the above-described laminate, a copper-ceramic composite including the above-described laminate, an electronic component including the above-described laminate, and an electronic device having the above-described electronic component mounted thereon.

As described above, the laminate of the present invention has excellent adhesion between the non-metal layer and the sintered copper powder paste layer. As described later in examples, the sintered copper metal structure of the copper powder paste sintered body has a crystal grain size of less than 10 μm even when sintered at a high temperature of, for example, 500 ℃.

In a preferred embodiment, the laminate of the present invention can be produced as a part of an electronic component, and can be provided as a part of a substrate such as a capacitor of an MLCC or an LTCC, for example. In a preferred embodiment, the laminate of the present invention comprises the following forms: in a ceramic multilayer substrate, a hole is formed in the substrate for interlayer connection, and copper powder paste is filled in the hole and fired to produce the ceramic multilayer substrate. In a preferred embodiment, the laminate of the present invention comprises a copper powder paste sintered body as an electrode, and for example, the electrode has a thickness of 0.1 to 1000. mu.m, preferably 0.3 to 100. mu.m, and more preferably 0.5 to 50 μm. In a preferred embodiment, the laminate of the present invention includes a copper powder paste sintered body as wiring of a circuit, and for example, a wiring pitch (circuit width) of 1 to 5000 μm, preferably 5 to 3000 μm is used.