JP2003323816A - Conductor composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductor composition which is approximate in heat shrinking behavior to an LTCC green sheet, can lessen deformation or warpage of a circuit substrate in simultaneous calcination to the minimum, has sufficient adhesion to the substrate and can be used in both inner layer and surface layer electrodes. <P>SOLUTION: The conductor composition is obtained by adding metal powder containing Ag or Ag and one or both of Pd and Pt and an organic vehicle, and optionally at least one of glass frit and a metal oxide and besides a solvent- resistant resin having solvent resistance to a solvent used in the organic vehicle and thermally decomposed in a temperature range of 200-700°C. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductor composition used for simultaneous firing of inner layer or surface layer electrodes in a multilayer circuit board or laminated electronic component made of low temperature fired ceramics.

[0002]

2. Description of the Related Art Low temperature firing ceramics (hereinafter referred to as "LTC
(C) is abbreviated as a multi-layer structure and capacitors and resistors can be formed at the same time. Therefore, it has been put to practical use as a circuit board for high-frequency circuit boards, high-frequency components, supercomputers, etc., and its demand is growing.

Since such LTCC can be fired at a lower temperature of about 800 to 1000 ° C. as compared with the conventional alumina multilayer substrate, it has a resistivity instead of molybdenum (Mo) or tungsten (W). It has become possible to use Ag-based conductors having a low value for the inner layer electrode and the surface layer electrode.

Further, since the surface layer electrode of the circuit board manufactured by LTCC is subjected to a plating process or the like in a later process,
The required characteristics are required according to those processes,
Since the surface layer electrode needs to have sufficient adhesion to the substrate, it is generally formed by using a conductor composition such as a paste different from that of the inner layer electrode.

[0005]

However, in general, LTCC green sheets have a large shrinkage onset temperature in the range of 600 to 900 ° C., whereas a conductor composition such as a paste containing Ag as a main component is usually 400 It shrinks largely at 600 ° C, and in the range of 600 ° C to 900 ° C, sintering does not proceed so much and shrinkage is small. Therefore, due to the difference in the heat shrinkage behavior between the two, LTCC green sheet and A
When a conductor composition such as a paste containing g as a main component is co-fired, the circuit board may be deformed or warped, and dimensional accuracy may not be obtained.

That is, when the conductor composition such as the paste for the surface layer electrode is fired separately from the LTCC green sheet, the deformation or warpage of the circuit board does not become a problem.
In many cases, a conductor composition such as a paste which has been used for a thick film wiring board such as a conventional 96% alumina board can be applied. However, if the conductor composition such as the paste for the surface electrode is L
When co-fired with the TCC green sheet, the circuit board may be deformed or warped as described above, and thus it is difficult to use as it is. LTCC for adhesion
It was necessary to design the conductor composition according to the type of.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems in the conventional conductor composition, and the thermal contraction behavior is similar to that of the LTCC green sheet, and the deformation and warpage of the circuit board during co-firing are prevented. It is an object of the present invention to provide a conductor composition which can be minimized and has sufficient adhesion to a substrate and can be used for both the inner layer and surface layer electrodes.

[0008]

The conductor composition according to the present invention has solvent resistance to a conductive metal powder, an organic vehicle, and an organic solvent used for the organic vehicle,
And a conductor composition composed of a resin that thermally decomposes at 200 to 700 ° C., wherein the metal powder is Ag or Ag.
The composition containing one or both metals of Pd and Pt, or the composition further containing at least one of a glass frit and a metal oxide, if necessary, solves the above problem in the conductor composition. It is characterized in that it is a means for doing.

In a preferred embodiment of the conductor composition according to the present invention, the content of the resin having solvent resistance to the organic solvent used for the organic vehicle and thermally decomposing at 200 to 700 ° C. 0.6 to 3 of the total amount of metal powder
5.4%, and in a further preferred embodiment, the conductor composition is used for forming electrodes for simultaneous firing of a multilayer circuit board or a laminated electronic component made of low temperature firing ceramics. It has a feature. In addition, all the numerical values of the percentage in this specification mean a mass ratio.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The conductor composition of the present invention will be described in detail below. In this specification, all numerical values of percentages and component composition ratios mean mass ratios unless otherwise specified. The conductor composition according to the present invention, in addition to the metal powder and the organic vehicle, has solvent resistance to the organic solvent used for the organic vehicle, and more than 200 to 7
The resin contains a resin that thermally decomposes in the temperature range of 00 ° C. The resin acts as an inclusion in the Ag thick film to be formed during co-firing with the LTCC green sheet.
The shrinkage and densification of the film due to the sintering of the particles are difficult to proceed. Further, even after the thermal decomposition of the resin, the densification of the Ag thick film does not rapidly proceed until the temperature range in which the glass component of the LTCC green sheet begins to soften and flow, and thus the pattern is schematically shown in FIG. As shown, the Ag thick film is maintained in a porous state. After the glass component of the LTCC green sheet softens and flows and starts shrinking, A
Since the glass component is sucked up into the baked film and the glass component of the LTCC green sheet penetrates into the Ag thick film,
The migration of Ag through the glass component is promoted, the sintering of Ag progresses at an accelerated rate, and the Ag thick film is densified.

Due to such an action, the heat shrinkage behaviors of the LTCC green sheet and the Ag thick film become close to each other,
Even in the co-firing, the deformation and warpage of the circuit board can be minimized. Further, the glass component is efficiently infiltrated into the Ag thick film, so that the adhesion with the substrate is improved after the co-firing.

At this time, from the viewpoint of further improving the adhesion to the substrate, glass frit and / or metal oxide may be added, if necessary. As the glass frit, borosilicate glass, phosphosilicate glass, or the like can be used and is not particularly limited. Also,
As the metal oxide, bismuth oxide (Bi ₂ O ₃ ), copper oxide (Cu ₂ O) and the like can be used, but the metal oxide is not particularly limited. When the glass frit and the metal oxide are added, it is desirable that the content is about 0.2 to 3.0% with respect to the total amount of the conductive metal powder, but this is not particularly limited.

The content of the above-mentioned resin having solvent resistance to the organic solvent used for the organic vehicle and thermally decomposing at 200 to 700 ° C. is 0 with respect to the total amount of the conductive metal powder. It is preferably contained in the range of 0.6 to 35.4%. That is, if the addition amount is less than 0.6%, the effect of addition is poor, while if the addition amount exceeds 35.4%, the glass component of the LTCC green sheet that has penetrated during co-firing is the Ag fired film surface. This is not preferable because the adhesion of the plating deteriorates when the Ag fired film is plated in a later step.

As the size of the above solvent resistant resin, it is preferable to use one having an average particle size of 0.5 to 15.0 μm for ease of paste production and screen printing of the paste, but its shape. The particle size is not necessarily limited to the above range. In order to avoid the occurrence of disconnection due to the local generation of voids in the sintered electrode, the grain size of 1/2 or less of the dry film thickness is formed. Is desirable.

It has solvent resistance to the organic solvent used in such an organic vehicle and has a temperature of 200 to 700 ° C.
As the resin that is thermally decomposed by, use of highly crosslinked acrylic powder, crystalline cellulose powder, highly crosslinked polystyrene powder, polyethylene powder, etc. as shown in Table 1 as an example of solvent resistance when combined with various organic solvents. You can That is, as shown in Table 1, these resin powders are resistant to organic solvents such as terpionell, mentanol and 2,2,4-trimethyl-3-hydroxypentylisobutyrate used in organic vehicles. It has been confirmed that it has sex.

[0016]

[Table 1]

It is also preferable that the conductive metal powder contains at least one metal selected from Pt and Pd in addition to Ag. This is because the solder resistance is better than that of Ag alone, and can be added when it is necessary to add solder resistance depending on the application. When Pt or Pd is added, the content of Pt in the whole metal powder is 0.5 to 3.0%, Pd
The content of Ag is preferably about 5.0 to 30.0%, and the content of Ag is preferably 65.0% or more, but is not particularly limited. In addition, in order to add Pt and Pd to the metal powder, all of them may be mixed in a powder state.
Alternatively, all or part of g, Pt, and Pd may be alloyed in advance and then powdered.

When the metal powder does not contain Pt or Pd, the content of Ag in the whole metal powder is 9%.
It is desirable to set it to 0.0% or more.

When Ag is used as the metal powder,
It is preferable that the average particle size is 0.5 to 15.0 μm for ease of paste production and screen printing of the paste, but the shape and particle size are not necessarily limited to the above range. is not. Also, Ag
When Pd or Pt is used in addition to the above, the average particle diameter of these is preferably 0.1 to 10.0 μm,
Similarly, it is not necessarily limited to this range.

The type of vehicle used in the conductor composition according to the present invention is not particularly limited, and a general conductive paste such as one prepared by dissolving ethyl cellulose in an organic solvent such as terpineol or menthanol. What is used for can be used. It is also possible to use an organic component containing a photosensitive compound to prepare a photosensitive conductive paste. The content of the organic vehicle is 7.0 to 10% of the total amount of the conductive composition.
It is desirable to set it to about 60.0%, but it is not particularly limited.

[0021]

EXAMPLES The present invention will be described below in more detail based on examples, but the present invention is not limited to these examples.

Examples 1 to 15 Ag powder having an average particle size of 2.4 μm, Pt powder having an average particle size of 0.5 μm, and highly crosslinked acrylic powder having an average particle size of 5.0 μm as a solvent-resistant resin (decomposition temperature : 280 to 380 ° C.), a crystalline cellulose powder having an average particle size of 14.0 μm (decomposition temperature: 200 to 660 ° C.) as a solvent resistant resin, and B ₂ O ₃ —SiO _2.
2- Al ₂ O ₃ -based glass frit and an organic vehicle in which ethyl cellulose was dissolved in menthanol were prepared at the ratios shown in Table 2, and were kneaded with a three-roll mill to obtain a conductive composition according to the present invention. Different types of conductive paste were prepared.

Comparative Example 1 The conductive paste according to Comparative Example 1 was obtained by similarly kneading only Ag powder and organic vehicle without mixing solvent resistant resin powder such as highly crosslinked acrylic powder and crystalline cellulose powder. Got ready.

Then, the conductive pastes according to these examples and comparative examples were prepared by using Al ₂ O ₃ powder and CaO-Al ₂ O _3-.
LTCC green sheet (thickness: 0..0) having a contraction start temperature of 730 ° C., which contains B ₂ O ₃ —SiO ₂ glass as a main component.
31 mm), a line-shaped pattern having a line width of 200 μm and a pad-shaped pattern of 5 mm × 5 mm and 2 mm × 2 mm are screen-printed, and then baked at 890 ° C. in a conveyor furnace to give a film thickness of 10 to 14 μm.
m Ag electrode was formed on the LTCC.

Next, the substrate deformation amount (substrate warpage amount) of the Ag electrode portion of the formed 5 mm × 5 mm pad-shaped pattern portion was measured. Further, an annealed copper wire having a diameter of 0.6 mm was soldered to the 2 mm × 2 mm pad-shaped pattern portion, and the adhesion strength was measured by a peel test. The measurement results are also shown in Table 2.

[0026]

[Table 2]

As is clear from the results shown in Table 1, the conductor composition according to the present invention containing a resin having solvent resistance to the organic solvent used for the organic vehicle and thermally decomposing at 200 to 700 ° C. It was confirmed that the amount of substrate deformation was small and the adhesion strength was excellent as compared with the case of the conductor composition of Comparative Example 1 containing no such solvent resistant resin.
However, in the conductor composition (Example 1) in which the ratio of the above resin is 0.3% with respect to the total content of the conductive metal powder, the effect of suppressing the substrate deformation is small, and the adhesion strength is relatively high. Turned out to be low. Further, in the conductor compositions (Examples 10 and 11) in which the ratio of the resin is 44.3% and 59.9% with respect to the metal powder content, the substrate deformation amount is small, but a viscosity suitable for screen printing is imparted. It is difficult to do this, and moreover, LTC penetrated during co-firing
It was confirmed that the glass component of the C green sheet covered the surface of the Ag fired film, and it is predicted that the adhesion of the plating would deteriorate when the Ag fired film was plated in a later step.

FIG. 2 is a SEM (scanning electron microscope) image of the surface of the fired film at each firing temperature in the case where the conductor composition according to the fifth embodiment is used as a representative example of the above-mentioned examples, in which a solvent resistant resin is added. Although not shown in comparison with the case of using the conductor composition of Comparative Example 1 which is not used, in Example 5 in which the highly crosslinked acrylic resin powder was added, 700 to 900 ° C.
It can be confirmed that the Ag fired film is rapidly densified in Comparative Example 1. However, in the case of the comparative example in which such a resin is not added, the densification is almost completed at 700 ° C. (before the start of LTCC shrinkage). It is recognized that they are doing.

[0029]

As described above, the conductor composition according to the present invention contains Ag, or Pd and P together with Ag.
In addition to at least one of a metal powder containing one or both of t, an organic vehicle, and optionally a glass frit and a metal oxide, and having solvent resistance to the organic solvent used in the organic vehicle, Moreover, 200-700
Since it is made of a resin that thermally decomposes in the temperature range of ℃, by using the conductor composition, it is possible to minimize the substrate deformation and warpage of the circuit board during co-firing, and it is possible to obtain a sufficient substrate Since it has adhesiveness, it can be applied to both formation of the inner layer electrode and formation of the surface layer electrode. As a result, it is possible to obtain high dimensional accuracy in the production of a circuit board by LTCC or in the production of a laminated electronic component, and it is possible to reduce the load of material management because the number of types of electrode forming materials is reduced, which is an extremely excellent effect. Is brought about.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a cross section of a fired film at each firing temperature in a case where a solvent resistant resin is added and a case where a solvent resistant resin is not added.

FIG. 2 is a scanning electron micrograph showing the state of the surface of a fired film at each firing temperature for Examples of the present invention to which a solvent resistant resin was added and Comparative Examples not added.

Claims (4)

[Claims] 1. A conductive metal powder, an organic vehicle,
A conductor composition comprising a resin having solvent resistance to an organic solvent used for the organic vehicle and thermally decomposing at 200 to 700 ° C., wherein the metal powder is silver (Ag) or silver (Ag). ), Palladium (Pd) and platinum (P
t) A conductor composition containing one or both metals. 2. A conductive metal powder, an organic vehicle,
One or both of glass frit and metal oxide,
A conductor composition comprising a resin having solvent resistance to an organic solvent used for the organic vehicle and thermally decomposing at 200 to 700 ° C., wherein the metal powder is silver (Ag),
Alternatively, a conductor composition containing silver (Ag) and one or both metals of palladium (Pd) and platinum (Pt). 3. The conductor composition according to claim 1, wherein the content of the resin is 0.6 to 35.4% of the total amount of the metal powder. 4. A multi-layer circuit board made of low-temperature fired ceramics or a laminated electronic component, which is used for forming an electrode for simultaneous firing.
The conductor composition according to one item.