JPS61219741A - Oxide dielectric material - Google Patents

Abstract

PURPOSE:To obtain the titled material which is excellent in the electrical characteristics and the strength, capable of the low-temp. calcination and suitable for a multilayered wiring substrate by constituting the material of glass ceramic contg. Mg2SiO4 forsterite and barium borosilicate glass in the specified weight ratio. CONSTITUTION:The powder of a raw material wherein Mg, Si, Ba and B are contained in 20-40wt% MgO, 34-40wt% SiO2, 9-28wt% BaO and 4-12wt% B2O3 expressed in terms of oxide is produced by mixing 40-80wt% Mg2SiO4 forsterite and 60-20wt% barium borosilicate glass and crushing the mixture. The slurry is produced by adding a binder (e.g. polyvinyl butyral) and a solvent (e.g. 1,1,1-trichloroethane). Successively the aimed oxide dielectric material is obtained by defoaming the slurry, deaerating he residual air, forming a green sheet with a general method and calcining it.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to oxide dielectric materials, and more particularly, to oxide dielectric materials having excellent electrical and mechanical properties.

The present invention relates to an oxide dielectric material that can be fired at low temperatures and is excellent particularly for use in circuit boards.

[Technical background of the invention and its problems] The development of microelectronics (ME) has rapidly pushed down the size of office automation equipment and home electronics equipment.

Miniaturized microelectronic devices are becoming commonplace. Relatively high-density multilayer wiring boards are widely used in microelectronic devices, but
As the material, alumina ceramic has been mainly used from the viewpoints of electrical properties, mechanical properties, and mass productivity. Such a multilayer wiring board can usually be obtained by alternately laminating dielectric layers and conductor layers, which serve as interlayer insulation, and then integrally firing them.

Although alumina (A 12o3) has excellent insulating properties, its firing temperature is as high as 1,500 to 1,800°C, so the conductor layer that can be used is molybdenum (A 12o3), which can withstand this firing temperature.
'No), and is limited to those made of high melting point metals such as tungsten (Ill). These materials, such as No. and W, have a high resistivity, so there is a limit to how much the wiring width can be reduced, which not only goes against the demand for miniaturization of devices due to high-density wiring, but also requires firing at high temperatures in a reducing atmosphere. Because of this, it was difficult to maintain and manage the firing equipment, which hindered efforts to reduce the number of man-hours.

On the other hand, platinum-silver (platinum-silver) has a lower resistivity than W, No.
Considering the use of pastes such as Pt-Ag), silver-gold (Ag-Au), and copper (Cu), it is desirable that the firing temperature of the dielectric material be about 1000°C or lower. In response to these demands, there is a method that uses glass-based ceramics containing lead oxide as a main component as a dielectric material (Japanese Patent Application Laid-open No. 78418/1983), and this material is A!
Although the firing temperature is lower than L203, it is still not sufficient.Furthermore, in systems containing lead oxide, some of the lead oxide is reduced during firing in a low partial pressure oxygen atmosphere (for Cu paste sintering), and the temperature is reduced as metallic lead. It precipitates out.

This significantly lowers the volume resistivity of the insulator layer made of dielectric material and causes signal leakage between wirings.

Furthermore, as devices become more compact and have higher-density wiring and faster speeds, the influence of the dielectric layer on signal propagation can no longer be ignored. So = 33.38 E (PS/
am), τ: delay time per l am), ε is preferably small. Also, dielectric loss (tan δ) has a large effect on signal loss, and if tan δ is large, the signal current causes electromagnetic damage to the dielectric layer around the wiring. fields are formed and converted into thermal energy, leading to signal loss. This thermal energy leads to an increase in the temperature of the board, causing troubles such as destruction of IC chips and melting of solder. Therefore, it is desired that tan δ be small.

As described above, it is desirable that the dielectric constant and dielectric loss of the dielectric material used for the substrate be small, and the conventional A1203. Glass ceramics (ε near-20, tan δ: 2X10
−3 to 4×10°” (at l MHz)) was not sufficient.

[Object of the Invention] An object of the present invention is to solve the above-mentioned problems, and to provide a device with excellent electrical and mechanical properties.

An object of the present invention is to provide an oxide dielectric material that can be fired at low temperatures.

[Summary of the Invention] The present invention is characterized in that Mg, Si, B, and Ba are respectively converted into oxides, Mg020 to 40% by weight, S+02 34 to
40% by weight.

This is an oxide dielectric material characterized by containing 9 to 28% by weight of Ba0 and 34 to 12% by weight of B2O and constituting a glass ceramic of Mg2SiO4 forsterite and barium borosilicate glass.

Silicon dioxide (Si02) in the dielectric material of the present invention dissolves in solid solution with magnesium oxide during firing, and forms a solid solution with NgSiO2.
If the ratio calculated as SiO2, which plays the role of forming 2-forsterite and forming a melt with boron oxide and barium oxide, is less than 34% by weight, magnesium oxide and the remaining components will separate and become impossible to sinter. .

If it exceeds 40% by weight, the transferability of the conductor paste (
Deterioration of volume resistance occurs due to migration (migration). Preferably it is 3B to 38% by weight.

Magnesium oxide (NgO) partially forms a solid solution with silicon dioxide to form a compound, and plays a role in imparting mechanical strength to the dielectric material of the present invention. Sufficient bending strength could not be obtained at 6 kg/Zenzen 2, which was lower than the required 15 kg/Layer 2,
If it exceeds 40% by weight in MgO terms, 1000℃
It becomes impossible to sinter at a lower temperature, and low temperature sintering cannot be achieved.
Preferably it is 27 to 32% by weight.

Barium oxide acts as a network-modifying oxide on network-forming oxides that form glass alone, such as silicon dioxide and boron oxide, forming a stable glass phase and playing a role in lowering the sintering temperature. If it is less than 9% by weight, the sintering temperature will rise, making it difficult to perform low-temperature sintering below 1000°C, and if it exceeds 28% by weight (calculated as BaO), foaming will occur during sintering and the mechanical strength will deteriorate. decreases to 15 kg/■■2 or less. Preferably it is 16 to 20% by weight.

Boron oxide becomes a network-forming oxide and forms a glass phase with silicon dioxide and barium oxide. It also plays a role in promoting sintering of a compound consisting of magnesium oxide and silicon dioxide and glass to obtain glass-ceramics of both. If it is less than 4% by weight, low-temperature sintering at 1000°C or less will be difficult, and if it exceeds 12% by weight, there will be too much fluid component, making it impossible to maintain the molded shape and leaving bubbles on the surface. This greatly affects paste printability, accuracy, etc. Preferably it is 7 to 9% by weight.

The material of the present invention may be prepared by mixing each of the constituent elements using oxides or salts that are converted into oxides by firing, and then sintering after firing, or by mixing Mg2SiO4 and B2O3-
SiO2-BaO glass may be used as a raw material to be crushed, mixed and sintered. In this case, it is difficult to sinter with Mg2SiO4 alone, and generally 1 in Ng2Si04 containing a sintering aid such as A fL203 is used. It is contained in an amount of about 3% by weight. If the amount is too high, the firing temperature of the material of the present invention may be increased to 1000℃.
℃ or more, but if the amount is about the same as a sintering aid, it will not have a particularly bad effect on the material of the present invention.Also, although the glass components also contain components that are unavoidable during manufacturing, If the amount is equivalent to that of an impurity, the same problem will not occur. For example, Cab, SrO.

Examples include K2O, TiO2, Fe2O3, Na2O, ZrO2 and the like.

Generally, there is no problem if it is 5% by weight or less, preferably 2% by weight or less, and PbO may also be contained, but as mentioned above, it has an adverse effect on the electrical characteristics, so if it is about 0.1% by weight. This is the limit.

The material of the present invention is Mg2SiO4 and B2O3-Si02-B.
Constructs glass ceramics with aO glass. Habo M
The amount of Mg2SiO4 is determined by the amount of gO, but M
When g2SiO4 is 40 to 80% by weight, a material with excellent mechanical strength and isovolume properties can be obtained. Since the best value is around 80% by weight, a more preferable range is 55 to 65% by weight. If the amount of glass is large, the mechanical strength will be poor, and if the amount is small, the sintering temperature will be high.

Next, one method for producing the oxide derivative material of the present invention will be explained.

Weigh a predetermined amount of Mg25f04 forsterite and barium borosilicate glass, and measure the average particle size using a wet vibrating mill. ,0
Mix and grind to about 1.13-.

A binder,
Add solvent etc. to make slurry. The binder and solvent can be selected as appropriate, but for example, PV, B (polyvinyl butyral) 5 to 5% as a binder to 100% by weight of the raw material powder.
20% by weight as solvent 1.1. ! ) Lichloroethane 25-35% by weight, n-butanol 10-22% by weight,
One containing 8 to 18% by weight of tetrachlorethylene and 4 to 13% by weight of tributyl phosphate is used. During mixing, the viscosity is reduced to 500CP to ensure uniform dispersion of raw materials! + degree. Thereafter, this slurry is defoamed to remove air dissolved in the slurry, and the slurry is made to have a viscosity of about 20,000 cpa in order to flatten the surface of the green sheet to be formed in the subsequent process and adjust its strength.

Using this slurry, a green sheet is prepared by a common method and fired in the air and nitrogen atmosphere to obtain the oxide derivative material of the present invention.

In the above method, forsterite and glass were used as raw materials, but each constituent raw material (MgO, SiO2゜Bad
, B2O3 or various salts in place of oxides by calcination, etc.) may be mixed, and forsterite may be formed by pyrolysis, etc. A slight deviation from the stoichiometric ratio does not affect the present invention, or In this case, it is effective to contain 1 to 3% by weight of ai2o3 as a sintering aid for Ng2S i04.

Especially Si0 38-38% by weight, IIIgo 27-3
2% by weight, Ba01B ~20 heavy weight X1B2O37~9
Those containing weight% are ε: 8.8~? ,0,ta
It has the characteristics of nδ: 4X104 or less and volume resistivity near X1G' or more.

It is particularly preferred because it allows firing at a low temperature of 980° C. or lower.

This is because the dielectric material of the present invention does not contain lead oxide.

There is no fear of precipitation of metallic lead, and the firing can be carried out regardless of the firing atmosphere. Therefore, various conductor pastes can be used, which is a great advantage in manufacturing circuit boards.

EXAMPLES Below, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

[Embodiment of the Invention] 1112 Forsterite (Mg2Si04) and barium borosilicate glass were weighed at a predetermined ratio and mixed in a non-aqueous wet mixing mill etc. so that the average particle size was about 1.0 to 2.0 mm. Mixed and pulverized to obtain a raw material powder, PVB (polyvinyl butyral) as a binder and 1 as a solvent were added to this raw powder as a binder.
,1. l-) Lichloroethane, n-butanol, tetrachlorethylene, tributyl phosphate, etc. were added to prepare a slurry. Viscosity is 500 cps due to uniform dispersion, etc.
It was set as the degree. After that, this slurry is degassed, the air dissolved in the slurry is degassed, and the surface of the green sheet to be formed in the subsequent process is flattened. 9 In order to adjust the strength, etc.,
The viscosity was approximately cps.

Similarly, products outside the scope of the present invention (Comparative Examples 1 to 5) were also produced.

A green sheet was prepared using this slurry according to a general method, and its properties are shown in Table 0. Incidentally, the calcination was performed in the air and in a nitrogen atmosphere to obtain the oxide derivative material of the present invention.

ε, 'tan δ, and ρ were printed concentrically with Ag paste on both sides of a disk-shaped sample by screen printing with 325 meshes, and after drying, were baked at 750°C for 20 minutes in the air.17.5■ A circular electrode with a shoulder diameter of φX15- was prepared and measured. @, tan δ is the value at I MHz,
ρ is applied at 25℃ and 50% humidity,
This is the lowest value after 1 minute.

The table also shows the composition after sintering. A
J1203 is a sintering aid in forsterite, and impurities include alkali metals, ZnO, etc.

In all cases, PbO was 0.07% by weight or less.

As is clear from the table, the dielectric material of the present invention has a
Possible to sinter at low temperatures below ℃, and resistance strength:
The mechanical properties are excellent at 15 kg/layer 2 or more, and the dielectric constant (
ε) Near ~ 8.0, dielectric loss tangent (tan δ): 3 x 104
~6×104 and volume resistance (Rma): 9X1G13~1
．． 3 X to'' electrical characteristics should also be satisfactory. Therefore, a material with such good characteristics should be
Because it can be fired at low temperatures, for example, conventional tungsten (W) and molybdenum (
Instead of NO), low-resistance materials such as copper (Cu), silver (Ag)-palladium (Pd), silver (Ag)-gold (Au), and resistance pastes such as RuO can be used, making the device compact. The goal is to achieve high-density wiring and reduce the number of manufacturing steps.

On the other hand, although Comparative Example 5 satisfied the required mechanical properties, the firing temperature was 1000°C or higher.

Comparative Example 3 can be fired at temperatures below 1000°C but does not satisfy the required mechanical properties.Comparative Example 1 has the required firing temperature and mechanical properties, and Comparative Examples 2 and 4 have the required firing temperature and It is difficult to use it practically because it cannot satisfy the physical and electrical characteristics.

[Effects of the Invention] As detailed above, the oxide dielectric material of the present invention has excellent electrical and mechanical properties and can be fired at low temperatures. For the required multilayer wiring board, or because ε and tan δ are small,
It can be expected to be used as a substrate for high-density hybrids equipped with LSIs, and its practical value is extremely large.

Claims (1)

[Scope of Claims] (I) Mg, Si, B, and Ba each contain 20 to 40% by weight of MgO, 234 to 40% by weight of SiO, 9 to 28% by weight of BaO, and 34 to 12% by weight of B_2O_ in terms of oxides. An oxide dielectric material comprising a glass ceramic of Mg_2SiO_4 forsterite and barium borosilicate glass. (2) Mg_2SiO_4 forsterite 40-8
The oxide dielectric material according to claim 1, containing 0% by weight. (3) Mg_2SiO_4 forsterite 55-6
The oxide dielectric material according to claim 1, containing 5% by weight.