JPH09268025A - Low-dielectric constant glass powder and printed circuit board using the same and resin-mixed material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain glass powder suitable for printed circuit boards and peripheral members thereof requiring both low dielectric constant and dielectric dissipation factor, and to obtain a printed circuit board and resin-mixed material by using this glass powder. SOLUTION: This glass powder is obtained from a glass having composition comprising 50-60wt.% SiO2 , 10-20wt.% Al2 O3 , 20-30wt.% B2 O3 , 0-5wt.% CaO, 0-4wt.% MgO, 0-0.5wt.% (Li2 O+Na2 O+K2 O) and 0.5-5wt.% TiO2 . The 2nd objective printed circuit board is obtained using this glass powder. The 3rd objective resin-mixed material suitable for the injection molding for peripheral members of the above sort of printed circuit board is obtained by mixing the glass powder with a resin and reinforcing fibers.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass powder, and more particularly to a glass powder suitable as an inorganic filler for a printed wiring board which is required to have a low dielectric constant and a low dielectric loss tangent or a plastic member around the printed wiring board. Further, the present invention relates to a printed wiring board using the glass powder as an inorganic filler and a resin mixture material for injection molding.

[0002]

2. Description of the Related Art In recent years, with the advent of an advanced information society, communication devices such as satellite broadcasting and mobile radio have tended to be digitized and have high-speed signal processing. It is desired that the substrate and the plastics member around the substrate have a low dielectric constant and a low dielectric loss tangent.
On the other hand, a technique for directly mounting an IC (printed wiring board) chip on a substrate has been introduced, and a high degree of dimensional stability is required for the printed wiring board, and a small thermal expansion is required. . In order to reduce the thermal expansion, conventionally, inorganic fillers such as glass powder have been widely used. In addition, as the plastics member around the printed wiring board, injection molded products of thermoplastic resin and thermosetting resin composition are often used, but since the surface hardness is low, an inorganic filler such as glass powder is used. It is also being added to increase the surface hardness.

However, since all the glass powders used for these have the composition of E glass which has been widely used as a filler for a long time, the dielectric constant and the dielectric loss tangent are large and the quality is sufficient. Was not. In addition, all other inorganic fillers such as calcium carbonate have a large dielectric constant and a large dielectric loss tangent, and are insufficient in quality.

[0004]

Generally, when an alternating current is passed through glass, the glass absorbs the alternating current as energy and absorbs it as heat. The absorbed dielectric loss energy is proportional to the dielectric constant and the dielectric loss tangent determined by the composition and structure of glass, and is represented by the following formula. W = kfv ² × εtan θ W is the dielectric loss energy, k is a constant, f is the frequency, v ²
Represents a potential gradient, ε represents a dielectric constant, and tan θ represents a dielectric loss tangent.
From this equation, it can be seen that the dielectric loss increases as the dielectric constant and the dielectric loss tangent increase, and the frequency increases.

However, since E glass has a relatively high dielectric constant and dielectric loss tangent, the plastics member using E glass cannot sufficiently meet the requirements. Further, as a glass showing a value lower than that of E glass, there is D glass having a relatively high ratio of SiO ₂ and B ₂ O _{3 in} the glass composition, but the fibers of D glass have poor meltability and striae and bubbles are generated. Since it is easy to do, there is a problem that the fiber is often cut in the spinning process, and productivity and workability are poor, which is not common. There is also the problem of poor water resistance.

[0006]

In order to solve the above problems, the present invention provides a glass powder from a glass which has a low dielectric constant and a low dielectric loss tangent and is excellent in solubility and water resistance. I am trying.

The glass composition of such chopped strands has a SiO ₂ content of 60% or less and TiO ₂ content.
Is set to 0.5 to 5% and the solubility of glass is improved while the total of Li ₂ O, Na ₂ O and K ₂ O is set to 0.5% or less, that is, in terms of weight%, SiO ₂ 50-6
0%, Al ₂ O ₃ 10 to 20%, B ₂ O ₃ 20 to ₃
0%, CaO 0-5%, MgO 0-4%, Li ₂ O
+ Na ₂ O + K ₂ O 0-0.5%, TiO ₂ 0.5
It is to be ~ 5%.

A glass powder having this glass composition is added to a thermoplastic resin or a thermosetting resin and molded to obtain a flat plate for a printed wiring board or its peripheral members which are required to have a low dielectric constant and a low dielectric loss tangent. A plastics material is obtained.

The glass powder of the present invention is preferably
% By weight, SiO ₂ 50-56%, Al ₂ O ₃ 14
-18%, B ₂ O ₃ 24-28%, CaO 0-2.
5%, MgO 0-2.5%, Li ₂ O 0-0.15
%, Na ₂ O 0 to 0.15%, K ₂ O 0 to 0.15
%, TiO ₂ 1 to 4%.

The reasons for limiting the composition of the glass fiber of the present invention are as follows. SiO ₂ is Al ₂ O ₃ , B ₂ O ₃
Together with the component forming the glass skeleton,
If it is less than%, the dielectric constant becomes too large. If it exceeds 60%, the viscosity becomes too high, the elution amount becomes low during spinning, the productivity decreases, and in some cases, fiberization becomes difficult. It is preferably 50 to 56%.

If Al ₂ O ₃ is less than 10%, a phase separation is likely to occur, resulting in poor water resistance. If it exceeds 20%, the liquidus temperature rises and the spinnability deteriorates. Therefore, Al ₂ O ₃ is limited to 10 to 20%, preferably 14 to 18%.

B ₂ O ₃ is a component used as a fluxing agent to lower the viscosity and facilitate melting, but if it is less than 20%, the dielectric loss tangent becomes too large. If it exceeds 30%, the water resistance tends to be poor. Therefore, B ₂ O ₃ is 10-20%
It is limited to, and preferably 24 to 28%.

CaO and MgO are both components that improve water resistance. However, when CaO exceeds 5% and MgO exceeds 4%, the dielectric constant and dielectric loss tangent become too large, so CaO is 0 to 5%, and MgO is It is limited to 0 to 4%, preferably C
aO is 0 to 2.5% and MgO is 0 to 2.5%.

Li ₂ O, Na ₂ O and K ₂ O are all used as fluxing agents, but if the total amount of these exceeds 0.5%, the dielectric loss tangent becomes too high and the water resistance becomes poor. Thus _{Li 2 O + Na 2 O +} K 2 O is limited to 0 to 0.5%, preferably Li ₂ O0~0.15%, Na ₂ O
It is 0 to 0.15% and K ₂ O is 0 to 0.15%.

TiO ₂ is effective in lowering the viscosity and the dielectric loss tangent, but if it is less than 0.5%, striae and unmelting occur during spinning, and the meltability deteriorates, and the dielectric constant is reduced. , The dielectric loss tangent becomes high. On the other hand, if it exceeds 5%, phase separation is likely to occur, resulting in poor chemical durability. Therefore, TiO ₂
Is limited to 0.5 to 5%, preferably 1 to 4%.

In the present invention, in addition to the above components, components such as ZrO ₂ F ₂ and SO ₃ can be contained up to 3% to the extent that glass properties are not impaired.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The glass powder of the present invention will be described in detail. First, SiO ₂ 50-60%, Al ₂ O ₃ 10-
_{20%, B 2 O 3 20~30} %, CaO 0~5%,
MgO 0-4%, Li ₂ O + Na ₂ O + K ₂ O0
A batch prepared to have a glass composition of 0.5% and TiO ₂ 0.5 to 5% is put in a platinum crucible and melted in an electric furnace at 1500 to 1550 ° C. for 8 hours under stirring. . Next, this molten glass was poured onto a carbon plate to form a glass bulk.

The glass powder of the present invention may be pulverized as it is, or may be pulverized after further melt-spinning the glass bulk to form fibers. For crushing glass bulk or fiberized glass, known methods such as a ball mill, a fred mill, a hammer mill, an orient mill, and an impeller mill can be used alone or in combination.

As the matrix resin which can be used for the resin mixture material for the printed wiring board or the injection molding of the present invention, for example, if it is a thermosetting resin, unsaturated polyester resin, phenol resin, epoxy resin, etc. Examples of the thermoplastic resin include polyethylene terephthalate resin, polybutylene terephthalate resin, polyacetal resin, polyamide resin, polyphenylene sulfide resin, fluororesin, and polyphenylene oxide resin. In particular, as a resin for printed wiring boards,
Epoxy resin, polyimide resin, unsaturated polyester resin, and fluororesin are preferable.

The ratio of the glass powder of the present invention to be mixed as an inorganic filler with respect to the matrix resin of the printed wiring board and the resin mixture material for injection molding is not particularly limited, but the volume content is not limited. At a rate of 1-5
0% is preferred. If it is less than 1%, the effect of lowering the coefficient of thermal expansion of the molded product cannot be seen, or if it exceeds 50%,
The impregnation may be poor.

The average particle size of the glass powder is not particularly limited, but is preferably 1 to 100 μm. When it is less than 1 μm, it becomes difficult to handle, and when it exceeds 100 μm, the surface smoothness of the molded product obtained when the laminate is molded or the injection molding is performed at the time of producing the printed wiring board. May get worse.

The resin mixture material for injection molding using the powder of the present invention as an inorganic filler is a mixture containing at least a matrix resin and chopped strands of reinforcing fibers, and glass powder as an inorganic filler. To obtain an injection-molded article from a resin mixed material containing the powder of the present invention as an inorganic filler, for example, pellets of a matrix resin, chopped strands of reinforcing fibers and the glass powder of the present invention are heated to form a matrix resin. A plastic molded member can be obtained by kneading the pellets while melting them to produce a resin mixture material in the form of pellets, and then injection-molding the obtained pellets of the resin mixture. The reinforcing fiber may be a reinforcing fiber normally used for fiber reinforced plastics, and for example, glass fiber,
Carbon fiber, aramid fiber, etc. can be used.

[0023]

Example The glass powder of the present invention shown below was prepared. Glass composition SiO ₂ 54.7%, Al ₂ O ₃ 14.0%, B ₂ O ₃
26.0%, CaO 1.0%, MgO 3.0%, L
i ₂ O 0.15%, Na ₂ O 0.015%, K ₂ O
0.00%, TiO ₂ 1.0% Average particle size (calculated from volume average) 29 μm When the dielectric constant and dielectric loss tangent of this glass powder were measured, the dielectric constant (1 MHz) was 4.4 and the dielectric loss tangent (1 MH).
z) was 0.0006.

As a comparative example, a glass powder having the following E glass composition was prepared. Glass composition SiO ₂ 54.5%, Al ₂ O ₃ 14.0%, B ₂ O ₃
7.0%, CaO 22.4%, MgO 0.6%, L
i ₂ O 0.2%, Na ₂ O 0.3%, K ₂ O 0.
015%, TiO ₂ 0.2% average particle diameter (number average) 29 μm The dielectric constant and dielectric loss tangent of the glass powder of this E glass composition were measured, and the dielectric constant (1 MHz) was 6.6 and the dielectric loss tangent (1 MHz). Was 0.0012.

Example 1 First, a varnish having the following ratio was prepared. Unsaturated polyester resin 100 parts by weight (Takeda Yakuhin Polymer 6304) Benzoyl peroxide (Kawaguchi Yakuhin) 2.2 parts by weight The glass powder of the present invention is kneaded into a varnish at a volume fraction of 50%. The kneaded product was added to glass paper (E glass, manufactured by Olivebest Co., 75 g / m ² ) at a resin content of 80% by weight, and to glass cloth (E glass, Nitto Boseki, 7628 type) at a resin content of 40% by weight. Then, the intermediate layer was impregnated with four pieces of glass paper, both surface layers were impregnated with glass cloth, and the copper foil was laminated on both upper and lower surfaces of the obtained laminate. The pieces were combined and heat-pressed to obtain a printed wiring board having a thickness of 1.6 mm.

After the copper foil of the obtained printed wiring board was removed by etching, the dielectric constant, dielectric loss tangent and thermal expansion coefficient were measured. The dielectric constant (1 MHz) was 3.8 and the dielectric loss tangent (1 MHz) was 0.0059, coefficient of thermal expansion (70 ~
(100 ° C.) was 31 × 10 ⁻⁶ / ° C.

[Example 2] 20% by weight of a glass chopped strand (manufactured by Nitto Boseki Co., E glass, fiber length 3 mm, fiber diameter 13 µm) in polyphenylene sulfide resin (T-4, manufactured by Topren Co., Ltd.) 20% by weight of glass powder was kneaded to obtain a resin material mixture, which was then injection molded to form a flat plate having a thickness of 2 mm.

The dielectric constant, dielectric loss tangent, and surface hardness (Rockwell hardness) of the obtained flat plate were measured. As a result, the dielectric constant (1M
Hz) is 3.9, and the dielectric loss tangent (1 MHz) is 0.001.
1, the surface hardness was 90.

Comparative Example 1 A glass circuit board having a thickness of 1.6 mm was obtained by molding the glass powder in the same manner as in Example 1 except that the glass powder having the E glass composition was used.

After removing the copper foil of the obtained printed wiring board by etching, the dielectric constant, dielectric loss tangent and thermal expansion coefficient were measured. The dielectric constant (1 MHz) was 4.2 and the dielectric loss tangent (1 MHz) was 0.012, coefficient of thermal expansion (70-1
(00 ° C.) was 35 × 10 ⁻⁶ / ° C.

Comparative Example 2 A flat plate having a thickness of 2 mm was obtained by molding in the same manner as in Example 2 except that the glass powder having the above E glass composition was used.

The dielectric constant, dielectric loss tangent, and surface hardness (Rockwell hardness) of the obtained flat plate were measured. As a result, the dielectric constant (1M
Hz) is 4.2, and dissipation factor (1 MHz) is 0.001
5, the surface hardness was 90.

[0033]

The glass powder of the present invention has a low dielectric constant and a low dielectric loss tangent as compared with the conventional E glass glass powder and the like, and also has a low coefficient of thermal expansion.
It is excellent for printed wiring boards that require low dielectric loss tangent, and the resulting printed wiring boards are also useful for communication equipment such as satellite broadcasting and mobile radio that require low dielectric constant and low dielectric loss tangent. . Further, a plastics member obtained by injection molding a resin mixed material containing the glass powder of the present invention as an inorganic filler is a conventional E
Since it has a surface hardness similar to that of plastics moldings containing glass powder of glass as an inorganic filler, it can be used as a plastics material that requires low dielectric constant and low dielectric loss tangent, such as around printed wiring boards. Are better.

Claims (4)

[Claims] 1. SiO ₂ 50-60% by weight, A
_{l 2 O 3 10~20%, B} 2 O 3 20~30%, C
aO 0-5%, MgO 0-4%, Li ₂ O + Na ₂
O + K ₂ O 0~0.5%, low dielectric constant glass powder characterized by having a glass composition of TiO ₂ 0.5 to 5%. 2. SiO ₂ 50-56% by weight, A
_{l 2 O 3 14~18%, B} 2 O 3 24~28%, C
aO 0-2.5%, MgO 0-2.5%, Li ₂ O
0 to 0.15%, Na ₂ O 0 to 0.15%, K ₂ O
The low dielectric constant glass powder according to claim 1, which has a glass composition of 0 to 0.15% and TiO _{2 of} 1 to 4%. 3. A printed wiring board containing the glass powder according to claim 1 or 2 as an inorganic filler. 4. A resin mixture material for injection molding containing the glass powder according to claim 1 or 2 as an inorganic filler.