JP2001189602A - High frequency component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high frequency component having a strip line, with which a sintering action difference or thermal expansion difference between a substrate and a conductor is reduced and a conductor loss is not damaged even when an additional component contained in the conductor is a little. SOLUTION: Concerning the high frequency component constituted by locating strip lines 2-4 having thickness more than that of at least one dielectric layer 1b inside a laminate substrate 1, with which plural dielectric layers composed of dielectric ceramic materials are laminated, the strip lines 2-4 are formed by being sintered integrally with the laminate substrate while using conductive paste having silver powder coated with at least one kind of organic metals Mg, Al and Ca so as to become 0.1 to 2 pts.wt. and β quartz of 7 to 9 pts.wt. in 100 pts.wt. silver powder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a high-frequency component used for, for example, a resonator, a filter, and the like.

[0002]

2. Description of the Related Art With the sintering of dielectric materials at low temperatures, high-frequency components for forming electronic circuits operating at high frequencies have been developed by using low-resistance materials such as silver and copper as materials for predetermined wiring patterns inside or on the surface. It has become very promising.

[0003] As this high-frequency component, an antenna circuit,
Examples include a resonance circuit using a strip line, a voltage-controlled oscillation circuit, a local oscillation signal forming circuit, and a power amplifier.

For example, an antenna circuit includes a laminated substrate on which dielectric layers are laminated, an internal wiring pattern such as a strip line disposed between the dielectric layers, and a surface wiring pattern disposed on the surface of the substrate. I was

FIG. 5 shows, for example, a dielectric layer on the lower surface side of a laminated substrate having a two-layer structure and its internal wiring pattern.

More specifically, three strip lines 3 are provided on the joint surface of the lower dielectric layer 31a constituting the laminated substrate.
An internal wiring pattern consisting of 2, 33 and 34 is formed.

An input terminal electrode 36 is formed on one side surface of the dielectric layer 31a, and an output terminal electrode 36 is formed on the other side surface. On the lower surface of the dielectric layer 31a, a conductor pattern 37 for coupling the input terminal electrode 35 and the strip line 32 and a conductor pattern 38 for coupling the output terminal electrode 36 and the strip line 34 are formed. Further, a ground conductor film is formed on the outer peripheral surface of the laminated substrate so that the various conductor patterns formed on the outer periphery of the substrate do not conduct. In FIG. 5, the ground conductor film 39 is formed on the surface except for the joint surface. Note that one end sides of the strip lines 32 and 33, which are internal wiring patterns, face a part of the conductor pattern 37 to form a coupling capacitance. One end of the strip line 34 faces a part of the conductor pattern 38 to form a coupling capacitance. The other end of each of the strip lines 32, 33, 34 is connected to a ground conductor film 39 formed on the outer periphery of the substrate.

As a result, the strip line 32 forms an LC resonance circuit with the ground conductor film 39 on the outer periphery of the substrate, and serves as a high-frequency trap circuit. The strip lines 33 and 34 constitute an LC resonance circuit by themselves, and are electromagnetically coupled to each other to form a high-frequency filter.

The other ends of the strip lines 32, 33, and 34 extend to the end face of the substrate as they are and are connected to the ground conductor film. The ground conductor film on the lower surface may be connected. Further, a surface wiring pattern for mounting other electronic component elements other than the ground conductor film can be formed on the front surface side of the substrate.

Also, the dielectric layer 3 of such a high-frequency component
For 1a and the like, a dielectric material that can be fired at a low temperature is used, and the strip lines 32, 33, and 34 and other conductor patterns are made of a low-resistance material such as Ag powder, Cu powder, or Au powder, glass frit, or organic powder. It is formed using a conductive paste obtained by kneading a vehicle. In addition, Au paste is
It has excellent conductivity, is chemically stable at all, and has good adhesion to the substrate. In particular, it has excellent weather resistance, but has the disadvantage of being very expensive.

The Cu paste, which is a main component of the Cu paste, is inexpensive and has excellent conductivity, but requires calcination in a reducing atmosphere, so that the calcination process becomes expensive. Therefore, in order to solve these difficulties, Ag paste is frequently used.

The use of an Ag paste as a conductive material is excellent in conductivity, the Ag powder as a main component is relatively inexpensive, and baking can be performed in the air.

In such a high-frequency component, strip lines 32 to 34 and conductor films to be various conductor patterns 37, 38 and 39 are formed on a green sheet serving as a dielectric layer by printing an Ag paste, and then each green sheet is formed. The sheets were laminated and formed by simultaneous firing. Thereafter, the ground conductor film 39 on the end face, the input / output terminal electrodes 35 and 36, and, if necessary, the surface wiring pattern and the like are formed by baking a conductive paste or the like. That is, in order to simplify the manufacturing process, it is formed by simultaneously firing a dielectric layer as a substrate material and a strip line as an internal wiring pattern.

In the high frequency component thus formed, the characteristics are greatly influenced by the resonance circuit characteristics of the strip lines 32 to 34. For example, conductor loss,
It is determined by dielectric loss and radiation loss.

Particularly, the conductor loss has a great influence, and the strip line formed on the dielectric green sheet by the conventional conductive paste screen printing method has a lens-shaped cross section at both ends and a thin conductor end. In this case, the loss of the electromagnetic field at that portion increases.

To prevent this, as shown in FIGS. 2 and 3, the strip lines 2, 3, and 4 are not formed by a screen printing method, but are formed in advance.
By forming holes in the regions to be 3 and 4 by punching in a groove shape and filling the groove portions with a conductive material, the cross-sectional shape of the strip lines 2, 3 and 4 is made substantially square, and The loss can be suppressed, the deterioration of the Q value of the resonator can be suppressed, and the insertion loss of the filter can be reduced.

Further, in the case where an IC chip or the like is mounted on the surface of a laminated substrate, for example, a heat sink can be formed in the mounting area by a method similar to the method of forming a filled strip line by filling. The effect of radiating heat from the chip can be promoted.

[0018]

In the above-mentioned high-frequency component, when a strip line corresponding to the thickness of at least one of the plurality of dielectric layers made of dielectric ceramic is formed, the volume of the conductor increases. . Therefore, warping of the substrate due to a difference in shrinkage behavior between the substrate and the conductor, and cracking of the substrate due to a difference in thermal shrinkage occur.

As a preventive measure, the addition of a glass having a low softening point has been used to match the shrinkage behavior with the substrate material. Also, the material used for the substrate material is
Added into the conductive paste forming the strip line,
There has been a method for minimizing the difference in heat shrinkage between a conductor and a substrate. Even with such a method, the difference in thermal expansion between the conductor and the substrate is reduced, but the thermal contraction of the conductor is not smaller than the thermal contraction of the substrate material. Therefore, a large amount of addition is required to reduce the thermal expansion difference, and the conductor loss increases.

In either method, the amount of glass or substrate material (substantially glass) in the conductive paste increases,
For this reason, the conductor loss of the strip line becomes large, and the characteristics of the resonance circuit are deteriorated.

The present invention has been devised in view of the above-mentioned problems, and has as its object to reduce the difference in sintering behavior and thermal expansion difference between a substrate and a conductor, even if the amount of additive contained in the conductor is small. An object of the present invention is to provide a high-frequency component having a strip line which is reduced in size and does not impair conductor loss.

[0022]

According to the present invention, silver having a thickness of at least one dielectric layer is mainly contained in a laminated substrate on which a plurality of dielectric layers made of a dielectric ceramic material are laminated. A high-frequency component having a strip line disposed therein, wherein the strip line is coated with 0.1 to 2 parts by weight of an organic compound of at least one metal of Mg, Al and Ca per 100 parts by weight of a silver component. A high-frequency component characterized by being formed integrally with a laminated substrate using a conductive paste having silver powder obtained and 7 to 9 parts by weight of β-quartz per 100 parts by weight of the silver powder. It is.

[0023]

The conductor material forming the strip line according to the present invention comprises:
By using silver powder as the main component, it can be made relatively inexpensively. Stable high-frequency characteristics can be obtained.

The silver powder is a powder coated with an organic metal. The silver powder described above can uniformly form a coating film of an organic compound of at least one metal of Mg, Al, and Ca on its surface. For this reason, sintering of silver powder can be effectively suppressed as compared with a conductive paste in which at least one metal of Mg, Al, Ca or an oxide thereof is added simultaneously with silver powder. Thus, the difference in shrinkage behavior between the substrate material and the conductor containing silver as a main component, which is generated during firing, can be reduced, and the warpage of the fired laminated substrate can be reduced.

Further, by adding 7 to 9 parts by weight of β-quartz glass to 100 parts by weight of silver powder coated with an organic metal, the difference in thermal expansion between the substrate material and the conductor material can be reduced. it can. In particular, since the coefficient of thermal expansion of β quartz glass is smaller than the coefficient of thermal expansion of the substrate material, even if a small amount of β quartz glass is added, the difference in thermal expansion between the substrate material and the conductor material of the strip line is reduced, and And the loss of the conductor can be reduced at the same time.

Taking into account only the difference in thermal expansion, 7 to 9 parts by weight is a small addition amount, but the addition of about 60% of the addition amount that theoretically eliminates the difference in thermal expansion due to the flexibility of the silver conductor itself makes it difficult for the substrate. Cracks can be prevented.

Even if a strip line having a film thickness of at least one dielectric layer is formed by using such a conductor paste, the laminated substrate has a small warp, no substrate crack due to a difference in thermal expansion, and a conductor A strip line with small loss is obtained, and as a result, the high-frequency characteristics are stabilized.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A high-frequency component according to the present invention will be described below with reference to the drawings.

FIG. 1 is an external perspective view of an antenna filter which is an example of the high-frequency component of the present invention. 2 is a sectional structural view, FIG. 3 is an exploded perspective view, and FIG. 4 is an equivalent circuit diagram.

In the figure, reference numeral 1 denotes a laminated substrate,
1c is a dielectric layer made of a dielectric ceramic material and an oxide or a low-melting glass material that can be fired at a low temperature;
2 to 4 are strip lines, 5 is a cavity portion,
Reference numeral 6 denotes a SAW filter.

Further, strip lines 2 to 4 forming a predetermined resonator are formed inside the laminated substrate 1. Specifically, the strip lines 2 to 4 partially have a thickness equivalent to the thickness of one dielectric layer, for example, 1b. Further, between the dielectric layers 1b and 1c, internal wiring patterns 11 to 14 for joining with the strip lines 2 to 4 and constituting a predetermined filter circuit are formed. Further, through holes 5a and 5b for forming the cavity 5 in which the SAW filter 6 is arranged are formed in the dielectric layers 1a and 1b.

The input terminal electrode 8 and the output terminal electrode 9 are provided on the side surfaces of the laminate 1 formed by laminating the dielectric layers 1a to 1c.
Are formed, and the ground conductor film 1 is formed around the input terminal electrode 8 and the output terminal electrode 9 so as not to conduct.
0 is formed.

A SAW filter 6 is disposed in the cavity 5, and its opening is covered with a lid 7.

The internal wiring pattern 11 disposed between the dielectric layer 1b and the dielectric layer 1c is a pattern for coupling the input terminal 8 and the strip line 3, and the internal wiring pattern 12 is This is a pattern for connecting to the SAW filter 6, and the internal wiring pattern 13
This is a pattern for connecting the W filter 6 and the output terminal electrode 9, and the internal wiring pattern 14 is a ground conductor film for mounting the SAW filter 6.

With such a configuration, the strip line 2
The first resonator is formed as a distributed constant from the inductance component of itself and the capacitance component between the ground conductor film 10 and the like. Further, the strip line 3 forms a second resonator centered on the strip line 3, and the strip line 4 forms a third resonator centered on the strip line. The second resonator and the third resonator are electromagnetically coupled to each other to form a filter having a predetermined pass band. Such a first resonator (trap circuit), a filter section, and the SAW filter 6 are connected in series with each other, and as a whole, an equivalent circuit shown in FIG. 4 is obtained.

The method of manufacturing the above-described high-frequency component will be briefly described. First, green sheets to be used as the dielectric layers 1a to 1c are prepared. For example, the green sheet is, for example, an inorganic filler of dielectric ceramic powder, for example, a low-melting glass powder for low-temperature firing, an organic binder such as alkyl methacrylate, a plasticizer such as DBP, and a toluene, for example. And the like, and kneaded with a ball mill for 48 hours to prepare a slurry. Here, the mixing ratio of the ceramic powder and the glass powder was 97 wt% of the ceramic powder and 3 wt% of the glass powder.

The slurry is formed into a tape by a doctor blade method or the like, and cut into a predetermined size to form a green sheet.

Then, a through hole serving as the cavity 5a is formed in the green sheet serving as the dielectric layer 1a, and at the same time, the ground conductor film 10 and the conductor serving as the input / output terminal electrodes 8 and 9 are formed on the front main surface thereof. The film is formed using a conductive paste containing silver as a main component.

Further, in the green sheet serving as the dielectric layer 1b, a through hole serving as the cavity portion 5b is formed, and a groove-like through hole forming a part of the strip lines 2-4 is formed.

Then, the inside of the groove-shaped through-holes forming a part of the strip lines 2 to 4 is filled with a conductive paste, and the strip lines 2 to 4 are formed on the surface of the dielectric layer 1b.
Is formed by printing a conductive paste.

On the green sheet to be the dielectric layer 1c, a conductive film to be the internal wiring patterns 11 to 14 is formed using a conductive paste containing silver as a main component.

Further, a conductor film serving as the ground conductor film 10 is provided on the main surface on the back side of the green sheet serving as the dielectric layer 1c.
It is formed using a conductive paste containing silver as a main component.

The dielectric layers 1a to 1c thus formed are laminated and integrally fired. Specifically, the baking treatment includes a binder removal step up to around 600 ° C.
And a firing step up to 0 ° C.

Thereafter, the input / output terminal electrodes 8 and 9 and the ground conductor film 10 are formed on the side surfaces of the laminated substrate 1 by baking a conductive paste.

Further, a SAW filter 6 having a predetermined filter characteristic is mounted in the cavity 5 and hermetically sealed with a lid 7 in a predetermined atmosphere.

In the above-described manufacturing process, the laminated substrate 1
The ground conductor film 10 and the input / output terminal electrodes 8 and 9 attached to the outer periphery of the substrate may not be formed on the green sheet but may be baked on the laminated substrate 1 after firing. Also, the green sheets were not formed in a lump, but, for example, after the green sheet serving as the dielectric layer 1c and the green sheet serving as the dielectric layer 1b were laminated, the green sheet serving as the dielectric layer 1b was formed. The conductive paste may be filled in the groove-shaped through-holes, and thereafter, a green sheet serving as the dielectric layer 1a may be laminated.

Here, the strip lines 2 to 4 have dielectrics in most areas from the open ends where a part is connected to the internal wiring patterns 11 and 12 to the short-circuit ends which are connected to the ground conductor film 10. It is composed of a conductor film having a thickness corresponding to the thickness of the body layer 1b (indicated by a dotted line in FIG. 3), and a portion on the short-circuit end side is thinner as in a normal internal wiring pattern.

A part of the short-circuit end portion extends from between the dielectric layer 1b and the dielectric layer 1c so as to be connected to the ground conductor film 10. Membrane (Figure 3
A via-hole conductor penetrating through the dielectric layers 1a and 1c may be formed at the short-circuited end portion (indicated by a dotted line).

Here, the conductive paste forming the internal wiring patterns 11 to 14 includes, for example, a predetermined amount of a metal powder such as an Ag powder, and if necessary, for example, a predetermined amount of a borosilicate low melting point glass. An organic binder such as ethyl cellulose and, for example, 2.2.4-trimethyl-1.3
An organic solvent such as pentadiol monoisobutyrate is mixed and kneaded with a three-roll mill.

Here, in order to form the film thickness portions of the strip lines 2 to 4, the conductive paste filled in the groove-shaped through-holes of the dielectric layer 1b is made of silver powder having an average particle size of 1 to 3 μm.
A powder coated with 0.1 to 2 parts by weight of an organic metal such as g, Al, or Ca is used.

If the amount is less than 0.1 part by weight, substrate warpage occurs, and if it exceeds 2 parts by weight, conductor loss increases and the Q value decreases. Further, 7 to 9 parts by weight of β quartz is added to the paste.

If the amount is less than 7 parts by weight, a crack is generated in the substrate due to a difference in thermal expansion between the conductor and the substrate. If the amount is more than 9 parts by weight, the conductor loss increases and the Q value decreases. A predetermined amount of the silver powder and β quartz are used, and an organic binder such as ethyl cellulose and an organic solvent such as 2.2.4-trimethyl-1.3-pentadiol monoisobutyrate are mixed. Knead to make.

Further, the conductive paste to be a conductive film to be adhered to the surface of the laminate 1 is, for example, a predetermined amount of Ag powder,
A metal powder such as Pt powder, a predetermined amount of the same dielectric ceramic material powder as the substrate, an organic binder such as ethyl cellulose, and 2.2.4-trimethyl-1.3, for example.
An organic solvent such as pentadiol monoisobutyrate is mixed and kneaded with a three-roll mill.

[0054]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, as a conductive paste for forming strip lines 2 to 4, Mg and A were added to Ag powder having an average particle size of 1 to 3 μm.
l, a powder coated with an organic metal such as Ca and β quartz glass are weighed and mixed as shown in Table 1, and an organic binder such as ethyl cellulose is used as a vehicle in an organic solvent such as pentadiol isobutrate as a vehicle. And a dispersant were added thereto and mixed well using a three-roll mill.

Further, the viscosity was adjusted using an organic solvent such as the above-mentioned pentadiol isobutrate to obtain a desired conductive paste.

[0056]

[Table 1]

First, in preparing a substrate material, MgTiO ₃ , CaTiO ₃ , B
Raw material powders of glass components such as ₂ O ₃ and Li ₂ CO ₃ are weighed, and pure water is added to the raw material powders as a medium for 24 hours.
After mixing in a ball mill using rO ₂ balls, the mixture was dried and then calcined at 750 ° C. for 3 hours in the atmosphere.

An acrylic acid-based binder, a plasticizer and the like were added to the obtained calcined product, and a green sheet was obtained by a doctor blade method.

Next, a conductor paste is printed on the green sheets corresponding to the first dielectric layers 1a and 1c by a screen printing method, and the green sheets corresponding to the first dielectric layers 1b are previously positioned at predetermined positions. A groove-like hole is formed, and the above-mentioned filling paste is filled.

These three green sheets were heated and pressed, and then fired at 950 ° C.

The warpage of the ceramic fired product thus obtained, cracks around the film thickness portions of the strip lines 2 to 4, and conductor loss were measured.

It should be noted that the warpage was 10 μm or less, good without cracks, and the Q value was good at 200 or more.

Table 1 shows the results.

It can be seen from Tables 1 and 2 that cracks occur due to the difference in thermal expansion between the substrate and the conductor as the volume of the conductor portion of the film thickness of the strip lines 2 to 4 increases.

When the amount of β-quartz is less than 7 parts by weight based on 100 parts by weight of silver powder, cracks occur due to the difference in thermal expansion from the samples Nos. 3, 4, 5 and 6 in Table 1, and 9 parts by weight If it exceeds, the amount of glass in the conductor increases and the Q value deteriorates. Therefore, the optimal amount of β-quartz is 7 to 9 parts by weight with respect to 100 parts by weight of silver powder.

Sample Nos. 4, 7, 8, 9, and 10 in Table 1 show the amount of the coating of the organometallic product on the silver powder,
It is the result of changing from 0 to 3 parts by weight with respect to parts by weight. When the coating amount is 0.1 parts by weight or more, warpage is reduced. When the coating amount exceeded 2 parts by weight, deterioration of the Q value was observed.

Sample No. 4 and Sample No. 11 in Table 1 are different from low-softening point glass or coated products added for reducing warpage. Low softening point glass must be added up to 4 parts by weight in order to reduce warpage, and the Q value is impaired. Since the sintering behavior can be controlled with a smaller addition amount by using the organometallic coating product, the warpage can be improved without impairing the Q value.

In the above-described example, an example in which an antenna filter is used is shown. However, a resonance circuit using a strip line, a voltage-controlled oscillation circuit using a strip line, and a local oscillation signal forming circuit using a strip line are described. Also, the present invention can be widely applied to power amplifiers and the like using strip lines.

[0069]

As described above, according to the present invention, a strip line having a thickness corresponding to at least one layer of a dielectric layer is formed by using an organometallic coating product on silver powder and adding β quartz. It is formed using the conductor material described above.

As a result, the warpage of the substrate is effectively suppressed, cracks around the strip line are prevented, and an excellent strip line with little deterioration of the Q value is obtained. As a result, a high-frequency component with improved characteristics is obtained.

[Brief description of the drawings]

FIG. 1 is an external perspective view of an antenna filter which is an example of a high-frequency component of the present invention.

FIG. 2 is a structural view showing a cross section taken along line XX in FIG.

FIG. 3 is an exploded perspective view of the high antenna filter of the present invention.

FIG. 4 is an equivalent circuit diagram thereof.

FIG. 5 is a perspective view of a part of a conventional high-frequency component.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Laminated substrate 2-4 ... Strip line 5 ... Cavity part 6 ... SAW filter

Claims (1)

[Claims] A strip line mainly composed of silver having a thickness of at least one dielectric layer is arranged inside a laminated substrate on which a plurality of dielectric layers made of a dielectric ceramic material are laminated. In the high-frequency component, the strip line is based on 100 parts by weight of a silver component.
A conductive material having 0.1 to 2 parts by weight of a silver powder coated with an organic compound of at least one metal of Mg, Al and Ca, and 7 to 9 parts by weight of β-quartz per 100 parts by weight of the silver powder A high-frequency component characterized by being formed integrally with a laminate substrate using a conductive paste.