JPH1116418A - Copper metallized composition and glass ceramic wiring board using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition in which an abnormal shape such as the projection of a via hole conductor on a glass ceramic surface is reduced by including glass frit having the specified softening point in Cu, Cu2 O, a mixture of CuCuO2 or a mixture of Cu-CuO. SOLUTION: A copper metallized composition of via hole has Cu, Cu2 O, a mixture of Cu-Cute, or a mixture of Cu-CuO as the main component, and glass frit for mutually diffusing with glass ceramic has a softening point of 700-1000 deg.C, and a content to the main component of 0.5-35.0 wt.% based on the total weight containing organic vehicle. The main component of the copper metallized composition is preferable to be globular powder having a mean particle size of 1-10 μm, preferably 3-6 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper metallized composition for via holes which can be co-fired with glass ceramic porcelain, and a glass ceramic porcelain co-fired with the glass ceramic porcelain using the copper metallized composition. The present invention relates to a glass-ceramic wiring board suitable for various circuit boards, high-frequency multilayer wiring boards, etc., on which low-resistance via-hole conductors having high adhesive strength due to good contraction matching with an insulating substrate are formed.

[0002]

2. Description of the Related Art Conventionally, as an insulating base for various wiring substrates such as a package for accommodating a semiconductor element such as an IC or an LSI or a hybrid integrated circuit device having various electronic components mounted thereon in addition to the semiconductor element. Alumina ceramics have been widely used because of their excellent properties such as electrical insulation and chemical stability.

However, in recent years, a wiring board on which a semiconductor element such as an IC or an LSI which has been operated at a higher frequency and a higher density is mounted has a lower dielectric constant and a lower wiring resistance than the insulating base made of alumina ceramics. Glass insulators are required as such insulating substrates, and low-resistance conductors that can be co-fired with the glass ceramics and have low firing temperatures include, for example, copper (Cu), gold (Au), and silver (Ag). ), The formation of a wiring layer has attracted attention.

An insulating substrate made of the above glass ceramic has been developed as a glass ceramic wiring board combined with a low-resistance conductor for a wiring board used in a communication field where the frequency and density are increasing. Wiring using Cu as a resistance conductor has been eagerly developed.

[0005] Such a glass ceramic wiring board is generally formed by forming a slurry prepared using a glass ceramic raw material powder, an organic binder and a solvent by a sheet forming method such as a doctor blade method, and then forming a via hole in the obtained glass ceramic green sheet. After punching and filling the via hole with a copper paste containing a copper metallizing composition, a predetermined wiring pattern is formed on the green sheet using a similar copper paste by a conventionally known thick film method such as a screen printing method. It has been produced by laminating a plurality of print-formed sheets under pressure, then heating the laminate to remove the binder, and then firing.

[0006] As a copper metallized composition applied for the above purpose, a low-temperature sintering type conductive paste containing copper or a copper alloy as a main component has been proposed (Japanese Patent Laid-Open No. 1-11 / 1991).
2605, JP-A-63-301405).

[0007]

However, when the above-mentioned conductive paste is filled in a via hole formed in a glass ceramic green sheet, there is a problem in wettability with the glass ceramic. There was a problem that the adhesive strength with glass ceramic porcelain was weak.

In addition, when co-firing with glass ceramic, the sintering start temperature of the copper metallized composition and the glass ceramic porcelain are different, resulting in a shift in shrinkage during the sintering process. Inadvertently protruding from the surface, as a result, there is a problem that a connection failure due to unevenness of a silicon chip connection portion of a semiconductor element, a connection failure of various chip components, or a connection failure of wire bonding occurs.

[0009]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to first co-fire a copper metallized composition filled in a via hole and glass ceramic porcelain. The adhesive strength at the interface between the via-hole conductor obtained and the glass ceramic porcelain is high,
Stable adhesive strength is obtained, and there is no abnormal form such as the via-hole conductor protruding in the via-hole on the surface of the glass ceramic porcelain with the same shrinkage rate in the firing process. It is an object of the present invention to provide a glass-ceramic wiring board suitable for various circuit boards having the above and multilayer wiring boards for high frequencies.

[0010]

Means for Solving the Problems The present inventors have conducted intensive studies and found that a copper metallized composition for via holes containing Cu or Cu ₂ O or a Cu—Cu ₂ O mixture or a Cu—CuO mixture as a main component. By controlling the softening point of the glass frit contained therein to 700 to 1000 ° C. and controlling the difference in thermal expansion between the insulating substrate and the glass ceramic porcelain to 1 ppm / ° C. or less, the copper metallized composition filled in the via hole and the glass ceramic porcelain It has been found that an abnormal form such as protrusion of the via-hole conductor from the surface of the glass ceramic porcelain can be reduced while maintaining a high adhesive strength with the glass ceramic porcelain.

That is, the copper metallized composition of the present invention comprises:
A copper metallized composition for via holes that can be co-fired with glass ceramic porcelain at a temperature of 00 to 1000 ° C,
The composition contains, as a main component, a glass frit having a softening point of 700 to 1000 ° C. in Cu or Cu ₂ O, or a Cu—Cu ₂ O mixture or a Cu—CuO mixture with respect to the total amount including an organic vehicle. -35.0% by weight.

In particular, it is more preferable that the content of the glass frit is 15.0 to 25.0% by weight in total.

The glass-ceramic wiring board using the copper metallized composition of the present invention has a softening point of 700 to 10.
The glass frit of 00 ° C. is added in an amount of 0.5 to 35.0% by weight based on the total amount including the organic vehicle, based on Cu or Cu ₂ O, or a main component consisting of a Cu—Cu ₂ O mixture or a Cu—CuO mixture. It has a via-hole conductor formed by simultaneously firing the contained copper metallized composition and glass ceramic porcelain at a temperature of 800 to 1000 ° C. in a nitrogen atmosphere.

In particular, it is more desirable that the total content of glass frit in the copper metallized composition is 15.0 to 25.0% by weight.

[0015]

According to the present invention, since the copper metallized composition for via holes contains a glass frit having a softening point of 700 to 1000 ° C., it can be simultaneously fired at a temperature of 800 to 1000 ° C. Since coexistence of the coefficient of thermal expansion is obtained, when co-firing at the above-mentioned temperature, the glass frit reacts with the glass ceramic porcelain, and the glass in the copper metallization and the glass ceramic porcelain of the insulating substrate interdiffuse, thereby reducing the adhesive strength. In other words, the adhesive strength between the via-hole conductor and the glass ceramic porcelain is improved, and the shrinkage of the glass frit by firing and the mutual diffusion of the glass into the glass ceramic porcelain promote the shrinkage of the copper metallized composition filled in the via hole. As a result, abnormal forms such as protrusion of via-hole conductors on the surface of glass ceramic porcelain are extremely small. There can be obtained a glass ceramic wiring board.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the copper metallized composition of the present invention and a glass ceramic wiring board using the same will be described in detail.

The copper metallized composition of the present invention may be Cu or Cu ₂ O, or a Cu—Cu ₂ O mixture or Cu—C
As a glass frit containing a uO mixture as a main component and interdiffusing with a glass ceramic porcelain, its softening point is 700 to
At 1000 ° C., the content of the main component accounts for 0.5 to 35.0% by weight based on the total amount including the organic vehicle.

In the present invention, the main component in the copper metallized composition has an average particle size of 1 to 10 μm (specific surface area by BET method is 0.1 to 0.5 m ² / g), preferably 3 ~ 6 μm (specific surface area by BET method is 0.2 ~
It is preferable to use spherical powder of 0.4 m ² / g).

The main component Cu or Cu ₂ O, or a Cu—Cu ₂ O mixture or a Cu—CuO mixture is reduced to Cu after sintering to become a conductor. and the protruding suppressed and from the viewpoint of reducing the specific resistance, Cu-Cu ₂ O mixture or Cu-CuO mixture is more preferable.

Next, as the glass frit in the present invention, for example, lead borosilicate glass, borosilicate glass,
Zinc borosilicate glass, lithium silicate glass, silica (SiO ₂ ) and the like can be mentioned, and borosilicate glass and silica (SiO ₂ ) are particularly desirable from the viewpoint of component compatibility with glass ceramic porcelain.

The glass frit is a spherical powder having an average particle size of 0.5 to 10 μm, preferably 2 to 7 μm.
m is optimal.

On the other hand, the softening point of the glass frit is 70
If the temperature is lower than 0 ° C., the sintering is inconsistent with the glass ceramic porcelain, unilaterally diffuses into the glass ceramic, and the adhesive strength is not developed.
If the temperature exceeds 0 ° C., as described above, sintering mismatch may cause poor sintering of the copper metallized composition. Therefore, the softening point of the glass frit of the present invention is specified at 700 to 1000 ° C.,
In particular, those having a softening point of 800 to 1000 ° C. are most desirable in terms of consistency of the sintering temperature.

On the other hand, the content of the glass frit is
When the amount is less than 0.5% by weight based on the total amount of the main component containing the organic vehicle, the effect of suppressing the protrusion of the via-hole conductor is extremely small. Exceeds 10 μΩ · cm, the content is specified in the range of 0.5 to 35.0% by weight.

In particular, the content of the glass frit is more preferably 15.0 to 25.0% by weight from the viewpoint of achieving both the protrusion of the via hole conductor and the specific resistance of the via hole portion.

Next, the glass-ceramic wiring board of the present invention is characterized in that the copper metallized composition is treated in a nitrogen atmosphere at 800 to
It has a via-hole conductor formed by simultaneous firing with a glass ceramic porcelain at a temperature of 1000 ° C.

That is, the via-hole conductor is fired under the above-mentioned firing conditions using the copper metallized composition of the present invention, whereby a sintered product obtained by simultaneously firing the glass ceramic wiring board and the copper metallized composition is obtained. In this case, no problems occur due to the adhesive strength or the protrusion of the via-hole conductor.

Next, when a copper paste is prepared using the copper metallized composition, the binder in the organic vehicle added to the copper metallized composition includes acrylic having excellent thermal decomposability in a nitrogen atmosphere. The binder is preferably an acrylic resin having a molecular weight of 500,000 or less, and the solvent for the vehicle is dibutyl phthalate,
Dioctyl phthalate or the like is preferable, and the copper paste contains a binder in an amount of 1.0 to 1.0 parts by weight based on 100 parts by weight of an inorganic component.
It is prepared by adding and mixing 10.0 parts by weight and a solvent.

As the glass ceramic porcelain composition applied to the present invention, one composed of a glass component and a ceramic filler component is used, and the glass component is not particularly limited. Desirable lithium-based crystallized glass that can reduce the difference,
The adhesive strength with the via-hole conductor can be improved.

When the glass component in the glass ceramic porcelain is a lithium silicate glass, particularly a crystalline glass, the copper metallized composition contains Al as a metal oxide.
By adding a metal such as ₂ O ₃ or Ni, or a combination thereof, the viscosity of the glass component is effectively reduced, and the glass component is reduced to Cu.
It can also penetrate between particles.

On the other hand, as the ceramic filler component, Al ₂ O ₃ , SiO ₂ , MgO, CaO, forsterite and the like can be used.

Next, the insulating base of the glass ceramic wiring board is prepared by, for example, adding an organic binder excellent in thermal decomposability and having a molecular weight of 500,000 or less and a plasticizer in a nitrogen atmosphere to a raw material powder composed of lithium silicate glass and ceramic filler; The slurry prepared by appropriately adding a solvent or the like is formed by a well-known sheet forming method.

At predetermined positions on the surface of the green sheet thus obtained, the paste containing the copper metallizing composition as described above is used to fill the via holes, and a conductive pattern is formed using the same paste. A plurality of sheets are pressed and laminated while being aligned.

Thereafter, the laminate is subjected to a heat treatment to remove the binder, and subsequently, 800 to 1000 in a nitrogen atmosphere.
By simultaneously firing the glass ceramic porcelain and the copper metallized composition at a temperature of 850 ° C., more preferably 850 to 950 ° C., a glass ceramic wiring board having a via-hole conductor made of the copper metallized composition of the present invention can be obtained.

[0034]

EXAMPLE The copper metallized composition of the present invention and a glass ceramic wiring board using the same were evaluated as follows based on one example.

First, with respect to the main component of the copper metallized composition having an average particle size of 5 μm, various glass frit having different softening points were weighed at the ratio shown in Table 1 with respect to the total amount including the organic vehicle, and the molecular weight was calculated. Then, an organic binder and a solvent, whose amounts were appropriately adjusted, were added and kneaded to prepare paste-like copper metallization samples for via holes and conductor patterns.

On the other hand, an organic binder of an acrylic resin, a plasticizer, and a solvent are added to raw material powder obtained by adding ceramic powder as a filler component to lithium silicate glass so as to have a composition that sinters at a temperature of 800 to 1000 ° C. The slurry thus prepared was formed into a green sheet having a thickness of 0.2 mm constituting an insulating substrate by a doctor blade method.

After drilling a via hole having a hole diameter of 0.15 mm in the green sheet thus obtained using an NC punching apparatus, the via hole is filled with a copper metallizing sample for the via hole by a printing method, and a conductor is further formed on the upper surface thereof. A predetermined pattern was formed by printing using a copper metallizing sample for a pattern.

Next, a copper metallizing sample is filled in a via hole, a plurality of the green sheets having a predetermined pattern are laminated, and the green sheet is heated in a nitrogen atmosphere to remove the binder. Then, the via hole is heated at a temperature shown in Table 1. A conductor, a wiring conductor, and an insulating substrate were simultaneously fired to produce a glass ceramic wiring substrate for evaluation.

Using the glass-ceramic wiring board for evaluation, a via hole penetrating both sides of the wiring board was formed by four holes.
The resistance was measured by the terminal method, the thickness of the wiring board and the diameter of the via hole were measured, the specific resistance was calculated, and the average value was obtained.

The protruding height of the via hole is measured by a stylus method using a surface roughness meter, and the average value is obtained. A silicon chip is mounted on the via hole and a void immediately below the silicon chip is formed. After investigating the occurrence of
Those with a protrusion height of less than 35 μm have a void generation rate of 10%
It was within, and what exceeded it was judged to be defective.

Next, the plating property is firstly set to N in the via hole.
The i-plate was coated with a thickness of 3 μm and the Au plating was coated with a thickness of 1 μm to evaluate the presence or absence of chipping.

On the other hand, with respect to the connection reliability with the silicon chip, the void immediately below the silicon chip was measured by an ultrasonic flaw detection method, and the void generation rate was 5% or less, 10% or less good and 10% or more. Was determined to be defective.

Based on the individual evaluations described above, the overall evaluation was excellent, good, and poor.

[0044]

[Table 1]

As can be seen from the table, all of the components outside the scope of the present invention have a large specific resistance in the via hole portion, have a projection height of 35 μm or more, have a lack of plating, have a silicon chip. It can be understood that the connection reliability of the via hole portion is not satisfied, and that all the items are not satisfied.

The present invention is not limited to the above-described embodiment.

[0047]

As described in detail above, the copper metallized composition of the present invention and the glass-ceramic wiring board using the same are made of Cu or Cu ₂ O, a Cu—Cu ₂ O mixture or a Cu—CuO mixture. For via holes that can be co-fired with glass-ceramic porcelain containing 0.5 to 35.0% by weight, based on the total amount of glass frit having a softening point of 700 to 1000 ° C. as the main component and the organic vehicle. Since the glass frit in the copper metallized composition reacts with the glass ceramic porcelain serving as the insulating substrate, the shrinkage of the copper metallized composition for the via hole is promoted, and the glass ceramic porcelain is manufactured by using the copper metallized composition. Glass ceramics that maintain high bonding strength with the glass ceramic and that the via-hole conductors protrude very little from the glass ceramic porcelain surface. It can be obtained click wiring board.

Continued on the front page. (72) Inventor Yoji Kokubo 1-4-4 Yamashita-cho, Kokubu-shi, Kagoshima Inside Kyocera Research Institute (72) Inventor Tatsuya Tashiro 1-1-1, Yamashita-cho, Kokubu-shi, Kagoshima Kyocera Corporation Kagoshima Inside the Kokubu factory

Claims (4)

[Claims] 1. A copper metallized composition for via holes which can be co-fired with glass ceramic porcelain at a temperature of 800 to 1000 ° C., wherein the main component is Cu or Cu ₂ O, or a Cu—Cu ₂ O mixture or Cu— A copper metallized composition comprising a glass frit having a softening point of 700 to 1000 ° C in a total amount of 0.5 to 35.0% by weight based on a CuO mixture. 2. The glass frit is used in a total amount of 15.0 to 2
2. The copper metallized composition according to claim 1, wherein the composition is contained in an amount of 5.0% by weight. 3. The main component of Cu or Cu ₂ O or Cu
A copper metallized composition containing a glass frit having a softening point of 700 to 1000 ° C. in a total amount of 0.5 to 35.0% by weight with respect to a Cu ₂ O mixture or a Cu—CuO mixture in a nitrogen atmosphere at 800 to A glass-ceramic wiring board comprising a via-hole conductor formed by simultaneous firing with a glass-ceramic ceramic at a temperature of 1000 ° C. 4. The glass-ceramic wiring board according to claim 3, wherein the total content of glass frit in the copper metallized composition is 15.0 to 25.0% by weight.