JP3209304B2 - Laminated electronic component and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer electronic component such as an LC composite component, an inductor, a capacitor and the like used for forming various electronic circuits, and a method of manufacturing the same .

[0002]

2. Description of the Related Art Conventional multilayer electronic components have been manufactured by printing a conductor on a green sheet, stacking the sheets and integrally firing the sheets. However, this manufacturing method has a problem that conductor dimensions vary due to variations in sheet shrinkage during firing, and it is difficult to stably mass-produce electronic components having predetermined electrical characteristics.

[0003] Therefore, as a manufacturing method to solve this problem,
A manufacturing method using photolithography has been proposed. That is, a high-precision conductor is formed by photolithography on the surface of a fired substrate whose surface is mirror-polished, and then an adhesive is applied. Next, another fired substrate is stacked on the substrate, and vacuum-heat-compression bonding is performed to be integrated to obtain a product. In this manufacturing method, since the conductor is formed on the surface of the fired substrate, there is no need to worry about variations in sheet shrinkage during firing,
The dimensions of the conductor become highly accurate.

However, in this manufacturing method, a new problem arises in that the bonding strength between the substrates varies, and the bonding strength tends to be insufficient. Accordingly, an object of the present invention is to provide a multilayer electronic component having a small variation in adhesive strength between substrates and improved reliability of adhesive strength, and a method of manufacturing the same.
Is to provide a law .

[0005]

In order to solve the above problems, a laminated electronic component according to the present invention has a structure in which the upper and lower surfaces are ±
A plurality of fired ceramic substrates having a smoothness of 2 μm, and a conductor disposed between the plurality of fired ceramic substrates, wherein the fired ceramic substrate sandwiching the conductor is a vacuum. It is characterized in that bonding is performed by means of thermocompression bonding via a high heat resistant adhesive having a thickness of at least twice the conductor thickness. As a material for the ceramic substrate, a dielectric, a magnetic, a semiconductor ceramic, or a glass ceramic is used. As a material of the high heat resistant adhesive, any one of a polyimide resin and a polyamide resin is used. As the conductor, for example, there is a strip line. In the method for manufacturing a multilayer electronic component according to the present invention, a conductor is disposed between a plurality of fired ceramic substrates having upper and lower surfaces having a smoothness of ± 2 μm, and the conductor is sandwiched between the substrates. The baked ceramic substrate is bonded by means of vacuum heat compression through one of a polyimide adhesive and a polyamide adhesive having a heat resistance of at least twice the conductor thickness. And The high heat resistant adhesive is applied to the surface of the fired ceramic substrate by a spin coater.

[0006] In the above configuration, by setting the thickness of the high heat resistant adhesive to be at least twice the thickness of the conductor, the unevenness of the bonding surface is reduced. Therefore, the gap formed at the bonding interface is small, and even if the amount of plastic deformation of the adhesive during the vacuum heating and pressure bonding is small, the gap is sufficiently filled with the adhesive, thereby reducing bonding defects.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a multilayer electronic component according to the present invention and the same will be described.
One embodiment of the manufacturing method will be described with reference to the accompanying drawings. In the present embodiment, a strip line filter will be described as an example. As shown in FIG. 1, the strip line filter 15 is formed by bonding two fired ceramic substrates 1 and 6. Ceramic substrates 1, 6
Is obtained by kneading an insulator powder and a binder, molding the mixture, and firing the mixture. The ceramic substrates 1 and 6
The upper and lower surfaces are mirror polished, the plate thickness is 0.6 mm,
The upper and lower surfaces have a smoothness of ± 2 μm.

A pair of strip lines 2 and 3 and a ground conductor 4 are formed on the upper and lower surfaces of the ceramic substrate 1 by photolithography. The photolithographic technique is a known technique. The lead portion 2a of the strip line 2 is exposed at the left edge of the ceramic substrate 1, and the lead portion 2b is exposed at a position on the left side of the front edge of the substrate 1. Leader 3a of strip line 3
Is exposed on the right side edge of the ceramic substrate 1 and the drawer 3
b is exposed at a position on the right side of the front edge of the ceramic substrate 1. The ground conductor 4 is formed on the entire surface of the ceramic substrate 1. The strip lines 2 and 3 and the ground conductor 4 are made of Ag, Ag-Pd, Cu, or the like.

The above-mentioned two ceramic substrates 1 and 6 are bonded by the procedure described below. A high heat-resistant and thermoplastic polyimide adhesive in a molten state is uniformly applied to the upper surface of the ceramic substrate 1 by a spin coater. Similarly, the polyimide adhesive is uniformly applied to the lower surface of the ceramic substrate 6. At this time, the thickness of the polyimide adhesive applied to the ceramic substrates 1 and 6 is determined by the polyimide adhesive layer 14 (FIG. 2) after the ceramic substrates 1 and 6 are bonded.
And FIG. 3) is set to be twice or more the thickness of the strip lines 2 and 3. Therefore, the polyimide adhesive is applied relatively thickly.

The ceramic substrates 1 and 6 coated with the polyimide adhesive are pre-dried at a temperature of 150 ° C. for one hour.
The solvent component of the polyimide adhesive is removed. The surface of the polyimide adhesive applied to the ceramic substrate 1 has small irregularities. This is because the thicker polyimide adhesive is applied to the strip lines 2 and 3 provided on the upper surface of the ceramic substrate 1.
This is because most of the steps due to the above are absorbed. On the other hand, the surface of the polyimide adhesive applied to the ceramic substrate 6 is
Almost no irregularities.

Next, the ceramic substrates 1 and 6 are stacked together with their surfaces coated with a polyimide adhesive so that the strip lines 2 and 3 are disposed therebetween, and are vacuum-heat-pressed. Since the surface of the polyimide adhesive applied to the ceramic substrates 1 and 6 is small even if it has irregularities, the gap formed at the bonding interface is small, and even if the amount of plastic deformation of the adhesive during vacuum heating and pressure bonding is small, Then, the gap is sufficiently filled with the adhesive, and as shown in FIGS. 2 and 3, the polyimide adhesive layer 14 having no adhesion failure is formed. Thus, a strip line filter 15 having a structure in which the ceramic substrates 1 and 6 are joined via the polyimide adhesive layer 14 is obtained. An input / output electrode 7 is provided on the left end surface of the strip line filter 15 in a state of being electrically connected to the lead portion 2a of the strip line 2. Similarly, an input / output electrode 8 is provided on the right end face portion while being electrically connected to the lead portion 3a of the strip line 3. Ground electrodes 9, 10, and 11 are provided on the end face on the near side.

FIG. 4 is an equivalent electric circuit diagram of the strip line filter 15. The inductance L1 of the strip line 2 and the capacitance C1 formed between the strip line 2 and the ground conductor 4 constitute one resonance circuit, and the inductance L2 of the strip line 3
The capacitance C2 formed between the strip line 3 and the ground conductor 4 constitutes the other resonance circuit. The two resonance circuits are electrically coupled by a mutual inductance M.

Further, the results of an adhesive strength test and a heat cycle test of samples manufactured by varying the thickness of the polyimide adhesive applied to the ceramic substrates 1 and 6 will be described. In this test, the conditions of the vacuum heating and compression bonding were as follows: the degree of vacuum was 10 ⁻² Torr, the heating temperature was 350 ° C.,
The pressure was set at 10 kg / cm ² . The thickness of the strip lines 2 and 3 is 7 μm. The heat cycle test was carried out at a temperature of −55 ° C. for 30 minutes and then at 125 ° C.
Letting it stand at this temperature for 30 minutes was defined as one cycle, and this was repeated 100 cycles. When the thickness of the polyimide adhesive layer 14 after bonding was in the range of 2 to 13 μm, the bonding strength was 1 kg / mm ² or less. Then, when the peripheral portions of the strip lines 2 and 3 were cut out and observed with a microscope, gaps 17a and 17b were generated at the bonding interface as shown in FIG. Further, in the sample after the heat cycle test, peeling was observed at the bonding interface.

On the other hand, when the thickness of the polyimide adhesive layer 14 after bonding is in the range of 14 to 24 μm, the bonding strength is 1 kg / kg.
mm ² or more, and even when the peripheral portions of the strip lines 2 and 3 were cut out and observed with a microscope, no gap was observed at the bonding interface as shown in FIG. No abnormality was observed in the sample after the heat cycle test. The multilayer electronic component and the method of manufacturing the same according to the present invention are not limited to the above-described embodiment, but can be variously modified within the scope of the invention.

It is not necessary to use a high-heat-resistant adhesive in a molten state, and a sheet-like high-heat-resistant adhesive is sandwiched between two substrates, and the substrates are bonded by vacuum heating and pressure bonding. There may be. The material may be a polyamide adhesive. Further, although the above-described embodiment describes a stripline filter, the present invention is not limited to this, and may be a laminated electronic component such as an inductor, a capacitor, or an LC filter.

[0016]

As is apparent from the above description, according to the present invention, since the thickness of the high heat resistant adhesive is set to be twice or more the thickness of the conductor, the unevenness of the bonding surface is reduced. Thus, the gap formed at the bonding interface becomes smaller. Therefore, even if the amount of plastic deformation of the adhesive during the vacuum heating and pressure bonding is small, the gap is sufficiently filled with the adhesive, thereby reducing bonding defects and improving the reliability of the bonding strength. In addition, since it is difficult for gas such as moisture or flux contained in the outside air to enter the inside of the component from the bonding surface, the conductor is protected from erosion by moisture or flux.

[Brief description of the drawings]

FIG. 1 is an assembled perspective view showing one embodiment of a multilayer electronic component according to the present invention.

FIG. 2 is a perspective view showing an appearance of the strip line filter shown in FIG.

FIG. 3 is a sectional view taken along the line III-III of FIG. 2;

FIG. 4 is an equivalent electric circuit diagram of the strip line filter shown in FIG. 2;

FIG. 5 is an enlarged cross-sectional view around a strip line of a test sample.

FIG. 6 is an enlarged cross-sectional view around a strip line of a test sample.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Ceramic substrate 2, 3 ... Strip line 6 ... Ceramic substrate 14 ... High heat resistant adhesive layer 15 ... Strip line filter

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-54-104555 (JP, A) JP-A-55-65280 (JP, A) JP-A-58-204521 (JP, A) JP-A-4- 111304 (JP, A) JP-A-5-14101 (JP, A)

Claims (3)

(57) [Claims] A plurality of fired ceramic substrates having upper and lower surfaces having a smoothness of ± 2 μm; and a conductor disposed between the plurality of fired ceramic substrates. The sandwiched and fired ceramic substrate is joined by means of vacuum heating and pressure bonding via a high heat resistant adhesive of one of a polyimide adhesive and a polyamide adhesive having a thickness of at least twice the conductor thickness. A laminated electronic component characterized by the above-mentioned. 2. The multilayer electronic component according to claim 1, wherein said conductor is a strip line. 3. A conductor is provided between a plurality of fired ceramic substrates whose upper and lower surfaces have a smoothness of ± 2 μm,
Any one of a polyimide adhesive and a polyamide adhesive having a thickness of at least twice the conductor thickness obtained by coating the fired ceramic substrate with the conductor interposed therebetween on a surface of the fired ceramic substrate by a spin coater. A method of manufacturing a laminated electronic component, comprising joining the two electronic components by means of vacuum heat compression through two high heat resistant adhesives.