JP2002080240A - Low dielectric constant alkali-free glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low dielectric constant alkali-free glass enabling simultaneous firing with a silver electrode and keeping insulation level of an electronic circuit substrate which can be directed to a green sheet for an electronic circuit substrate. SOLUTION: This low dielectric constant alkali-free glass substantially comprises in mol% 60-80 of SiO2, 12 to 25 of B2O3, 0.5 to 8 of PbO, 0 to 9 of Al2O3 and 0 to 7 of MgO+CaO+ZnO.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a low dielectric constant alkali-free glass suitable for a green sheet for an electronic circuit board.

[0002]

2. Description of the Related Art Alumina substrates made by sintering alumina powder have been widely used as electronic circuit substrates. However, the sintering temperature of alumina powder is about 160
Since the temperature is as high as 0 ° C., tungsten (melting point: 3400
° C) and molybdenum (melting point: 2620 ° C). That is, on the alumina substrate,
Silver having a lower specific resistance than these refractory metals (melting point: 96
(2 ° C.) cannot be used as an electrode material to be fired simultaneously with the production of the substrate.

In order to solve this problem, a method has been developed in which an alkali borosilicate glass powder having a low dielectric constant and a low dielectric loss is formed into a green sheet, which is fired to obtain an electronic circuit board. The firing temperature in this method is typically 900 ° C. or lower, and for example, silver can be used as a material for an electrode which is fired simultaneously with the production of the substrate.

[0004]

The conventional alkali borosilicate glass used for the green sheet has the following problems. That is, in an electronic circuit board manufactured by firing a green sheet using alkali borosilicate glass, silver is diffused into the electronic circuit board by simultaneous firing with a silver electrode, thereby lowering the insulating property of the electronic circuit board. There was a problem. An object of the present invention is to provide a low dielectric constant alkali-free glass that solves the above-mentioned problems.

[0005]

SUMMARY OF THE INVENTION The present invention, in mol% based on the following _{oxides, SiO 2 60~80%, B 2} O 3 12~25%, PbO 0.5~8%, Al 2 O _A low dielectric constant alkali-free glass consisting essentially of _{30 to} 9%, MgO + CaO + ZnO 0 to 7%.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The low dielectric constant alkali-free glass of the present invention (hereinafter simply referred to as the glass of the present invention) is usually powdered into glass powder. When this glass powder is used for producing an electronic circuit board, it is usually used as a green sheet. That is, the glass powder is mixed with the resin.
At the time of the mixing, an inorganic powder such as a ceramic filler, a plasticizer and the like are added as necessary. Next, a slurry is formed by adding a solvent or the like, and the slurry is formed into a sheet shape on a film such as polyethylene terephthalate by a doctor blade method or the like. Finally, it is dried to remove the solvent and the like to obtain a green sheet.

As the resin, polyvinyl butyral,
Acrylic resin, etc., as the ceramic filler,
α-quartz, amorphous silica, alumina, magnesia, forsterite, cordierite, mullite, zircon,
Examples of the plasticizer include powders of zirconia and the like, and examples of the plasticizer include dibutyl phthalate, dioctyl phthalate, and butylbenzyl phthalate.

The firing temperature T _B of the glass of the present invention is 9
It is preferably 50 ° C. or lower. If the temperature exceeds 950 ° C., simultaneous firing with a silver electrode becomes difficult. More preferably 900 ° C
It is as follows. The term “sinterable” as used herein is as follows. That is, 20 g of glass powder having an average particle size in the range of 1 to 5 μm is pressure-formed into a columnar shape having a diameter of 12.7 mm, and the resultant is heated to a temperature T, baked for 30 minutes, cooled, and then cooled. The fired body thus obtained is immersed in a red penetrant (red ink), taken out and washed with water, and the case where no coloration is observed in the fired body is referred to as “bakable”. T is 95
0 ℃ firing if T _B when it is 950 ° C. or less.

The dielectric constant ε at 1 MHz at 20 ° C. of the glass of the present invention is preferably 5.4 or less. 5.
If it exceeds 4, application to a green sheet for an electronic circuit board may be difficult. It is more preferably at most 4.9, particularly preferably at most 4.4.

The dielectric loss tan δ at 1 MHz at 20 ° C. of the glass of the present invention is preferably 0.0010 or less. If it exceeds 0.001, application to a green sheet for an electronic circuit board may be difficult. It is more preferably 0.0008 or less, particularly preferably 0.0006 or less.

Next, the composition of the glass of the present invention will be described below by simply writing mol% as%. SiO ₂ is a network former and a component that lowers ε, and is essential. If it is less than 60%, the chemical durability decreases or ε increases. Preferably it is at least 65%. The 80% glass melting temperature becomes too high, or, T _B becomes too high softening point may become 950 ° C. greater. Preferably it is 77% or less.

B ₂ O ₃ is a network former and is essential. If it is less than 12%, the glass melting temperature becomes too high and vitrification becomes difficult. Preferably it is 16% or more. If it exceeds 25%, the chemical durability decreases. Preferably it is 23% or less.

[0013] PbO component lowering the T _B or tan,
It is a component that reduces δ and is essential. Is T _B becomes high with less than 0.5%. It is preferably at least 2%. 8%
Above that, ε increases. It is preferably at most 7%, preferably at most 6%.

Al ₂ O ₃ is not essential, but may be contained up to 9% in order to stabilize the glass or suppress phase separation. If it exceeds 9%, the glass melting temperature may be too high, or ε may be too high.

Although MgO, CaO and ZnO are not essential, they may be contained in a total content of these three components up to 7% in order to lower the glass melting temperature. If it exceeds 7%, the glass may be devitrified. It is preferably at most 6%.

The glass of the present invention consists essentially of the above-mentioned components, but may contain other components as long as the object of the present invention is not impaired. The total content of the "other components" is preferably 7% or less. If it exceeds 7%, the glass may be devitrified. It is more preferably at most 5%.

The following are examples of the "other components". That is, in order to lower the glass melting temperature or to lower T _B , TiO ₂ , Zr
O ₂ , SrO, BaO, Bi ₂ O ₃ , and P ₂ O ₅ may be contained. Further, in order to color the glass, Fe ₂ O ₃ , Mn
Coloring components such as O, CuO, CoO, V ₂ O ₅ and Cr ₂ O ₃ may be contained.

The glass of the present invention is made of Li ₂ O, Na ₂ O, K ₂
It does not substantially contain an alkali metal oxide such as O, and the total content of these alkali metal oxides is typically 0.5
% Or less.

[0019]

EXAMPLES The raw materials were prepared and mixed so as to have the composition indicated by mol% in the column of SiO _{2 to} K ₂ O in the table, and the mixed raw materials were put in a platinum crucible and melted at 1650 ° C. for 120 minutes. Thereafter, the molten glass was poured out. A part of the obtained glass was pulverized with an alumina ball mill for 10 hours to obtain glass powder. The remaining glass was gradually cooled in a lump state at a temperature near the glass transition point T _g . Examples 1 to 5 are working examples, and example 6 is a comparative example.

For the glasses of Examples 1 to 6, T _g (unit:
° C), the firing state, ε, tan δ were measured or evaluated.
The results are shown in the table. T _g : Measured from room temperature to 1000 ° C. at a heating rate of 10 ° C./min by differential thermal analysis using glass powder as a sample. Alumina powder was used as a standard substance.

Firing state: 2 g of glass powder was 12.7 in diameter.
The sample was pressure-molded into a column of mm. The fired body obtained by holding the sample at 900 ° C. or 950 ° C. for 30 minutes was immersed in a red penetrant (Supertech UP-G3, manufactured by Martec), taken out, and washed with water. No color was observed in the fired body at 900 ° C (T _B ≤900
° C), and coloration was observed in the fired body at 900 ° C.
No color was observed in the fired body at 50 ° C. (90
0 ° C <T _B ≦ 950 ° C.) was evaluated as Δ, and a fired body at 950 ° C. that was colored (950 ° C. <T _B ) was evaluated as x.

Ε, tan δ: 60 g of 40 g of glass powder
Pressed into a m × 60 mm mold,
It was baked at 0 ° C. for 30 minutes. The obtained fired body is 50 mm ×
It was processed to 50 mm × 3 mm, and the dielectric constant and the dielectric loss at 1 MHz at 20 ° C. were measured using an LCR meter.

[0023]

[Table 1]

[0024]

By using the glass of the present invention for a green sheet for an electronic circuit board, copper (melting point: 1083) can be obtained.
℃), electrodes made of silver etc. can be fired simultaneously,
The insulating property of an electronic circuit board manufactured using the green sheet can be increased.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yumi Negishi 1150 Hazawa-cho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture F-term (reference) 4G062 AA10 AA18 BB05 CC10 DA06 DA07 DB01 DB02 DB03 DC04 DD01 DE01 DE02 DE03 DF02 DF03 EA01 EA10 EB01 EC01 ED01 ED02 ED03 EE01 EE02 EE03 EF01 EG01 FA01 FA10 FB01 FC01 FD01 FE01 FF01 FG01 FH01 FJ01 FK01 FL01 GA01 GA10 GB01 GC01 GD01 GE01 HH01 HH03 HH05 HH07 H01 KK01 GD01 GE01 MM27

Claims (3)

[Claims] In 1. A following oxides represented by _{mol%, SiO 2 60~80%, B 2} O 3 12~25%, PbO 0.5~8%, Al 2 O 3 0~9%, MgO + CaO + ZnO 0 ~ 7%, a low dielectric constant alkali-free glass consisting essentially of 2. The dielectric constant at 1 MHz at 20.degree.
The low dielectric constant alkali-free glass according to claim 1, which is 4 or less. 3. The low dielectric constant alkali-free glass according to claim 1, wherein the dielectric loss at 1 MHz at 20 ° C. is 0.0010 or less.