JPS60180952A - Circuit substrate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to a circuit board.

[Technical background of the invention and its problems]

Alumina has been conventionally used as a ceramic material for circuit boards. Alumina is commonly used because it has good insulation properties.

However, when alumina is used, the firing temperature is as high as 1,500 to 1,600°C, which limits the conductor paste that can be used. It was necessary to use a conductive paste made of tungsten, molybdenum, etc. that could sufficiently withstand the firing temperatures of However, the resistivity of W and Mo is on the side of 5.2 x 10-'Ω· compared to 1.6 x 10-'Ω· of Ag.

5.5 x 10"-'Ω・It is about three times as thick as the scratch. Therefore, in order to obtain a conductor path with the same conductivity, the conductor width must be made three times as wide at once, making high-density wiring impossible. There were drawbacks.

In order to eliminate these drawbacks, it is desired to develop a circuit board that can be fired at low temperatures without deteriorating properties such as insulation.

In response to such demands, the present inventors first developed Ba0
, 8n02, 1300℃ with B2O3 as the main component
We proposed a low-temperature sintered substrate that can be sintered at the following levels. The electrical properties such as insulation resistance and dielectric constant are equal to or higher than those of 11203, and it can be sintered at low temperatures, making it a very effective material.The inventors further investigated this substrate material. It was found that the tan δ of a specific composition is increased.

[Purpose of the invention]

The present invention has been made in consideration of the above points, and an object of the present invention is to provide a circuit board that can be fired at a low temperature and has a small dielectric loss.

[Summary of the invention]

The present invention is based on Ba8n(BO3)2 50-95 mo1%5n02
The circuit board is characterized in that it uses an oxide sintered body containing 5 to 50 mo% of the oxide.

By adopting such a composition, a circuit board that can be fired at a low temperature of 1300° C. or lower can be obtained. This board has a coefficient of thermal expansion α of about 6 to 9 (X 1 o-'/c), which is comparable to that of commercially available thick film paste for alumina boards, and there is little warping even when it is baked together with a conductor layer, making it suitable for use in circuit boards. suitable for Also other properties, such as dielectric constant g, 8.
6 to 10.0, dielectric loss Tan δ1 to 2 (X10-
3) It has insulation resistance ρ13 to 10 (X1013Ω/sub), which has sufficient characteristics as a circuit board. Also, the bending strength is 10
It has sufficient strength of 00 Kt/4 or more.

In the present invention, each component is limited for the following reasons.

First of all, Barn (BO3)2 itself has excellent characteristics as a circuit board, with a dielectric constant of 8.1 (IMHz
).

tan δ = 3.0 x 10-3(IM)lz)
, resistivity 14. ．． 0X1013Ω・α.

The coefficient of thermal expansion is 4.5 x 1 o-'/°C. Also Ba
rn (BOa )2 is a low-temperature firing composition that is densely sintered at an atmospheric width of about 1000°C.

Therefore, Ba8n(BO3)2 is 50moA! % or more is preferable, and the upper limit 95mo does not eliminate the effect of 5n02.
Limited to 1% or less.

Next is 5n02, which originally has semiconductor properties, so
Insulation resistance decreases, and the characteristics as an insulating substrate are no longer satisfied, and dielectric loss (tan δ) and relative permittivity (ε,) both increase, and the coefficient of thermal expansion (α) increases, etc. Generally speaking, it is thought that a problem occurs when tan
On the contrary, it was newly confirmed that it has a favorable characteristic that δ becomes smaller.

Furthermore, the melting point of 5n02 is 1620℃ and Burn (80
3) 2 If the reeds are too high and there is a lot of residue, the sintering temperature will rise, and at 8n0250 mol 1%, the temperature will be about 1300°C, which is the upper limit temperature for simultaneous sintering with metals such as Ag, Au, and Cu. Ag, Au, Cu, N
The melting points of i are 961℃, 1063℃, and 1084℃, respectively.
, 1452°C, Pd as a sintering agent,
A composition containing Pt, u203, 5i02, etc. is required.

The amount of 5n02 has a peak with favorable characteristics at 30-40mo7%.

The lower limit is 5mo1% at which the effect first appears.

Therefore, the range of 8n02 is limited to 5-50m01%,
Particularly suitable is 30 to 40 moJ%.

As described above, according to the present invention, it is possible to obtain an insulating substrate with a firing temperature of 1300°C or less, and in the case of M2O3, W
, Mo etc., Ag, Ag-Pd, Ag-
Since low-temperature firing pastes with low sheet resistance such as Ag-based pastes such as P 2 pastes and Cu pastes can be used, high-density wiring can be achieved, which is very effective. Furthermore, by lowering the firing temperature, energy costs during production can be reduced significantly.

An example of forming a co-sintered multilayer wiring board using the insulating substrate of the present invention will be described.

First, the desired BaO, 8n02. A slurry containing raw material powder having a B2O3 composition ratio is produced. The slurry consists of raw material powder, a binder such as polyvinyl butyral, a star-forming agent such as octyl phthalate, polyethylene glycol, etc.
Manufactured by adding a deflocculant such as menhaden oil and a solvent such as ethyl alcohol or trichloroethylene. Using this slurry, a green sheet is manufactured by a doctor blade method. Next, a first conductor layer is printed and applied using a conductor paste such as Ag-based and dried. Then the desired Bad, 8
n02, B2O3.

An insulating paste containing raw material powder having a composition ratio of kll 203 and Si02 is printed and coated on the first conductor layer, and after drying, a second conductor layer is formed in the same manner.

The insulating paste is made into a paste by adding butyl carpitol acetate, terpineol, ethyl cellulose, etc., and then applied.

The green sheets provided with two-layer wiring in this manner are simultaneously fired in an electric furnace at, for example, about 1000° C. for 3 hours to produce a multilayer wiring board.

The circuit board of the present invention is particularly suitable for use as a co-firing board having multilayer wiring. According to the present invention, it is possible to provide an insulating layer that can be fired at a low temperature, so instead of the conventional W, Mo, etc., Ag-based, Cu-based, Au-based, Ni-based, etc. with low sheet resistance can be used as the conductive layer. Paste can be used. In particular, since it does not contain a glass component, it has few pores and has a dense structure, so even if Ag-based materials are used, problems such as migration will not occur. Therefore, it is possible to increase the wiring density and achieve higher density. Also, A
For example, the amount of Pd in the g-based paste can be reduced, and a cost-effective substrate can be provided.

Conventionally, when a conductive paste such as W or Mo was used for M2O3, it was necessary to perform simultaneous sintering in a reducing atmosphere, but since Ag and Au can be used, it is possible to sinter in the air. It is also possible to obtain effects such as ease of manufacture and reduction in cost. In addition, since there is no glass component in the substrate, Ag
migration is less likely to occur.

Further, although this example is a printed multilayer, the same applies to a so-called green sheet multilayer.

Further, in the case of a printed multilayer, the circuit board of the present invention may be used as the substrate, but other substrates such as an M2O3 substrate or a mullite substrate may also be used.

The conventionally used 1203 board has M2O3 of 92~
Sintering temperature of about 1,500 to 16,000 for those containing 93%, εs = 10.5 to 12. tanδ=2~5X
10-3. ρ=0.2~5X1013. α':l:8
X 10-'/°C. In the present invention, as mentioned above, the sintering temperature is significantly lower than that of M2O3, and other properties can be obtained that are equivalent or higher. As required to increase transverse rupture strength, etc.

Other components such as IJ203, 5i02, etc. can also be added.

In addition, as mentioned above, since simultaneous firing is possible using a low-temperature firing paste, effects such as reduction in manufacturing costs can be obtained, but furthermore, by using Ag and lLu-based pastes, firing in the atmosphere is possible. There are also great effects such as increased production capacity, simplification of manufacturing equipment, and ease of work.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to obtain a circuit board that can be fired at a low temperature of about 130° C. or less, particularly about 800 to 1200° C.

Therefore, it is effective for high-density wiring, especially for multilayer wiring boards formed by integral sintering.

Therefore, it is also effective as a substrate for high-density non-bridled ICs on which LSI chips and the like are directly mounted.

[Embodiments of the invention]

The present invention will be explained in detail below. The circuit board of this example was manufactured as follows.

First, Bad, 8203,
A raw material powder of 5n02 was prepared, and the prepared powder was placed in an alumina pot together with alumina balls, and wet-pulverized for about 16 hours using a vibration mill.

This raw material powder may be used as something added to the oxide after sintering, such as carbonate, and in this example BaCO3, H
3BO3 and 5n02 were used. Then, it is dehydrated and dried,
After calcining by heat treatment at 1000 to 1400° C. for about 3 hours, it was placed again in an alumina pot and wet-pulverized for about 30 hours. Next, a binder such as polyvinyl alcohol (PV-A) was added and granulated to produce aggregates.

Thereafter, the aggregates were filled into a mold, pressure-molded at a pressure of about 1000 Kf/d, and fired in the atmosphere at 800 to 1200°C for 3 hours to prepare a sample.

As samples, a disk-shaped sample of 22 mφX 1 wm t and a bar-shaped sample of 20 x 3.5 x 3.5 tm+ were prepared, and various objects were measured. The results are shown in Table 1. The relative dielectric constant (ε, ), dielectric loss (tan δ), and resistivity (ρ) were determined by printing Ag paste in concentric circles on both sides of a disc-shaped sample by screen printing with 325 meshes, and after drying in the air. Baking treatment was performed at 750℃ for 20 minutes, and the
Measurements were made by forming a circular electrode with a diameter of 15 μm.

εS and tanδ are values at l MHz, and ρ is 25
This is the lowest value 1 minute after applying 100V under the conditions of 50% humidity and 50% humidity. Further, the coefficient of thermal expansion (α) was measured using a rod-shaped sample under the condition of a temperature change of 25 to 500C.

↓Kusen f. As is clear from Table 1 of the mortar, the embodiment of the present invention (2°3.4
), all of them were able to achieve a firing temperature of 1300°C or less, and other properties were also satisfactory. For example, even in a thermal shock test from 400°C to 25°C, there was no cracking or nematode. Although the bending strength is not shown, in any case it is 1
000~ or more. Alumina cracked during the Hook thermal shock test.

As is clear from Table 1, the addition of 8n02 increases tan
It was found that as δ decreases, it has static characteristics.

Also, in the case of a single component of Barn(BO3)2, α is 4.6X1
0-'/C, which caused warpage when fired together with commercially available AJgOs thick film paste, but this composition has α of 6 to 9X10-6/C and is a commercially available AJgOs thick film paste.
- Pd, Au eCu, kg - Same as Pt thick film paste, it has the characteristic of reducing warpage because it flops.

Agent Patent attorney Kensuke Norichika (and 1 other person) Procedural amendment (spontaneous) 1. Indication of the case Patent Application No. 59-34159 2. Name of the invention circuit board 3. Relationship of the person making the amendment to the case Patent Applicant (307) Toshiba Corporation 4, Agent Address: 105 Shibaura-Chome, Minato-ku, Tokyo 1-1 The scope of the claims of the specification is filed as attached.

A circuit board characterized in that an oxide sintered body according to the claims is used as an insulator.

Claims (1)

[Scope of Claim] A circuit board characterized in that an oxide sintered body containing 50 to 95 mo191 of Ba8n(803)2; and 5 to 50 mo1% of 5n02 is used as an insulator.