JPH04322007A - Glass composition and board for circuit - Google Patents

Abstract

PURPOSE:To provide a glass composition having adaptability to be formed into fibers, excellent dielectric characteristic in a high frequency zone, and enough chemical durability. CONSTITUTION:A glass composition containing respectively 40-65 percentage by mol of SiO2, 20-45 percentage by mol of at least one of MgO, CaO, SrO and BaO, 5-25 percentage by mol of at least one of TiO2 and ZrO2, and 0.5-15 percentage by mol of NbO5/2, the total amount of these oxides being 85 percentage by mol or more, having 9 or more of dielectric constant (1MHz, 25 deg.C), and having adaptability to be formed into fibers.

Description

[Detailed description of the invention]

0001

FIELD OF THE INVENTION This invention relates to a glass composition and a circuit board.

0002

BACKGROUND OF THE INVENTION In the age of advanced information technology, information transmission tends to become faster and more frequent. In new media such as mobile radios such as car telephones and personal radios, satellite broadcasting, satellite communications, and CATV, devices are becoming more compact, and as a result, microwave circuit elements such as dielectric resonators are becoming more compact. There is also a strong desire for miniaturization.

The size of a microwave circuit element is based on the wavelength of the electromagnetic waves used. The wavelength λ of an electromagnetic wave propagating in a dielectric material with relative permittivity εr is the propagation wavelength in vacuum λ0
Then, λ=λ0/(εr)0.5. Therefore, the larger the dielectric constant of the printed circuit board used, the smaller the device will be. Further, when the dielectric constant of the substrate is high, electromagnetic energy is concentrated within the substrate, which is advantageous because there is less leakage of electromagnetic waves.

[0004] As the above-mentioned printed circuit board, there is a board made by reinforcing a resin with a reinforcing material made of fibers of a glass composition (hereinafter referred to as "glass reinforcing material"). This printed circuit board is superior to ceramic substrates such as alumina in terms of cost and post-processing (cutting, hole punching, etc.). As a way to increase the dielectric constant of this printed circuit board,
Polyvinylidene fluoride (εr = 13) and cyano resin (
There is a method of using a resin with a high dielectric constant such as εr = 16 to 20), but in this case, the dielectric loss is large and there is also a problem with the stability of the dielectric properties in the high frequency range. It cannot be said to be an appropriate countermeasure because it lacks suitability as a countermeasure.

[0005] Also, high dielectric constant inorganic particles (for example, Ti
There is a method to improve the dielectric constant by using a resin in which O2 particles, BaTiO3 particles) are dispersed, but there is a problem that non-uniformity of the dielectric constant occurs on the substrate surface due to non-uniform dispersion of high dielectric constant inorganic particles. Since the appearance of the particle/resin interface is unfavorable in terms of long-term reliability, it cannot be said to be an appropriate countermeasure.

[0006] In addition to the above, there is a measure to improve the dielectric constant by using a glass reinforcing material (eg, glass cloth) with a high dielectric constant. Glass cloth for ordinary reinforcing materials is made of fibers of a SiO2-Al2O3-CaO-based glass composition called E-glass. More specifically, this E glass contains SiO2: 50 to 60% by weight, Al2O3:
13-16% by weight, B2O3: 5-9% by weight, Mg
O: 0-6% by weight, CaO: 15-25% by weight, Na2
O+K2 has a composition of O: 0 to 1% by weight, F: 0 to 1% by weight, and has a relative dielectric constant of about 6 to 7,
The dielectric constant is not so high.

[0007] As a glass composition having a high dielectric constant, Pb
There are lead-based glass compositions containing a large amount of O. for example,
PbO: 72% by weight, SiO2: 26% by weight, B2
A lead-based glass composition having a composition of 1.5% by weight of O3 and 0.5% by weight of K2O has a dielectric constant of 12.2. However, in the case of lead-based glass compositions, fiberization (diameter 7-9
There is a problem in that it is difficult to measure (μm). Pb during glass melting
The evaporation of O is intense and the fiber becomes non-uniform, resulting in frequent yarn breakage during the spinning process. Further, in the case of a lead-based glass composition, there is a problem in that it is difficult to form a glass cloth that is very suitable as a reinforcing material. In the case of manufacturing glass cloth, there is a heat treatment process to remove the primary binder, but lead-based glass compositions have a low strain point and easily deteriorate, so it is difficult to perform sufficient treatment. Glass cloth that is not sufficiently treated to remove the primary binder will cause a decline in the long-term reliability of the substrate. In addition, in the case of lead-based glass compositions, there is the problem that lead is toxic and it is not easy to handle.
There is also a problem that the dielectric loss (tan δ) is large in a high frequency range of z or higher.

Glass used as a reinforcing material for printed circuit boards also needs to have chemical durability. This is because the reinforcing material must not be damaged by the various chemical treatments that are used to form circuits on printed circuit boards.

[0009]

[Problems to be Solved by the Invention] In view of the above circumstances, the present invention aims to provide a glass composition that is suitable for fiberization, has excellent dielectric properties even in a high frequency range, and is highly chemically durable. The first challenge is to provide a circuit board with excellent dielectric properties even in the high frequency range and high long-term reliability.
This will be the subject of this study.

0010

[Means for Solving the Problems] In order to solve the above problems, the inventors have developed SiO2-BaO-TiO2-Zr
We focused on O2-based glass compositions. This is because this glass composition is lead-free, has good dielectric properties, and is rich in chemical durability (acid resistance, alkali resistance, and water resistance). However, there is a problem in that the devitrification temperature is high and fiberization is difficult. When obtaining glass fibers, the melt is drawn out from the small holes of a platinum pot called a bushing, which has 200 to 800 small holes in the bottom.
If the devitrification temperature is high, crystals due to devitrification will form at the bottom of the bushing, preventing the melt from flowing out and causing thread breakage. Normally, glass fiber is obtained while suppressing devitrification by controlling the temperature at the bottom of the bushing and the winding speed of the fiber, but the devitrification temperature exceeds the temperature at which the melt viscosity becomes 102.5 poise (316 poise). It cannot be completely controlled. If the viscosity of the melt is too low, control becomes impossible. In other words, the conventional high dielectric constant (εr is 9 or more) SiO2-BaO-TiO
The devitrification temperature of the 2-ZrO2-based glass composition exceeded the temperature at which the melt viscosity was 102.5 poise (316 poise), and it lacked suitability for fiberization.

[0011] Therefore, the inventors continued to conduct intensive studies in search of a way to provide fiberization suitability while ensuring the necessary dielectric properties and chemical durability, and found that the problem could be solved by adding an appropriate amount of NbO5/2. I was able to complete this invention by discovering what I could do. Therefore, in order to solve the first problem, the glass composition of the invention according to claim 1 is made of SiO
20 to 65 mol%, at least one of MgO, CaO, SrO and BaO, 20 to 45 mol%, Ti
At least one of O2 and ZrO2 at 5 to 25
mol%, NbO5/2, respectively, from 0.5 to 15 mol%, the total amount of these oxides is 85 mol% or more, and has a specific dielectric constant (1 MHz, 25°C) of 9 or more, which is suitable for fiber formation. In addition, the glass composition of the invention according to claim 2 has an SiO2 content of 46 to 60 mol%,
The content of at least one of MgO, CaO, SrO and BaO is 25 to 40 mol%, TiO2 and Zr
The content of at least one of O2 is 7 to 24 mol%,
The glass composition of the invention according to claim 3 has a structure in which the content of NbO5/2 is 1 to 10 mol%,
In addition, the content of at least one of MgO, CaO, SrO and BaO is 28 to 35 mol%, NbO5/2
The content is 2 to 9 mol%.

[0012] In order to solve the second problem,
A circuit board according to a fourth aspect of the invention has a structure in which a resin is reinforced with a reinforcing material made of fibers of the glass composition according to any one of claims 1 to 3. This invention will be explained in detail below. The glass composition of this invention is
Since the composition has the above composition, excellent properties such as a dielectric constant of 9 or more (1 MHz, 25° C.) and suitability for fiberization can be ensured as described below.

[0013] Specific dielectric constant (1 MHz, 25°C): High dielectric constant of 9 or more. ■ Dielectric loss (1MHz, 25°C), that is, tanδ0.
The loss is low, less than 6%. (2) Even in the high frequency range of 100 MHz, the above-mentioned dielectric constant and dielectric loss change only slightly, providing excellent high frequency dielectric properties. ■ Chemical durability (acid resistance, alkali resistance, water resistance)
rich in

■ The devitrification temperature and the melt viscosity are 102.5.
It is below the temperature at which it becomes poise, and has suitability for fiberization. There is a proportional relationship between the temperature difference between the devitrification temperature and the temperature at which the melt viscosity becomes 102.5 poise and the ease of fiberization. ■ The strain point is high at approximately 600℃. The reason why the composition range of the glass composition of the present invention is limited as described above is as follows.

SiO2: 40 to 65 mol% (more preferably 46 to 60 mol%) SiO2 is a component that forms the skeleton of glass, and
If it is less than 0 mol %, the devitrification temperature will increase and the melt viscosity will decrease, making it difficult to ensure the necessary fiberization suitability, and the chemical durability will also be insufficient. 9 if it exceeds 65 mol%
It is difficult to ensure the above dielectric constant, and the glass viscosity is high, making it difficult to melt and form into fibers.

At least one of MgO, CaO, SrO and BaO: 20 to 45 mol% (more preferably 2
(5 to 40 mol%) MgO, CaO, SrO, and BaO act as modifying ions of the glass structure and facilitate melting. Also,
Combined use results in a lower devitrification temperature. CaO, SrO
and BaO function to increase the dielectric constant. 20
If it is less than mol%, it is difficult to obtain a melt and the suitability for forming fibers decreases, and it is also difficult to ensure a dielectric constant of 9 or more. 45 mol%
If it exceeds this, the devitrification temperature increases and the melt viscosity decreases, making it difficult to ensure the necessary fiberization suitability.

At least one of TiO2 and ZrO2: 5 to 25 mol % (more preferably 7 to 24 mol %) TiO 2 and ZrO 2 have the function of increasing the dielectric constant and the chemical durability. TiO2 and Z
It is desirable to use rO2 in combination, and TiO2 is often used in a larger amount than ZrO2. If it is less than 5 mol%, it is difficult to ensure a dielectric constant of 9 or more and the necessary chemical durability. If it exceeds 25 mol%, the devitrification temperature increases and the suitability for forming fibers is lost.

NbO5/2: 0.5 to 15 mol% (more preferably 1 to 10 mol%) NbO5/2 has the function of greatly lowering the devitrification temperature without lowering the relative dielectric constant. If it is less than 0.5 mol %, the necessary addition effect will not be obtained, and if it exceeds 15 mol %, the devitrification temperature will increase. As claimed in claim 3, when the content of at least one of MgO, CaO, SrO and BaO is 28 to 35 mol% and the content of NbO5/2 is 2 to 9 mol%, the devitrification temperature This is preferred because there is a strong tendency for the difference between the temperatures at which the melt viscosity becomes 102.5 poise and the temperature at which the melt viscosity becomes 102.5 poise to become significant, and it is easy to ensure fiberization suitability.

Further, if the total amount of the above oxides is less than 85 mol %, it will be difficult to secure a dielectric constant of 9 or more, or it will be difficult to secure the necessary suitability for forming fibers. Note that the glass composition of the present invention contains TaO5/2 in a range of 15 mol% or less.
, AlO3/2 , LaO3/2 , CeO2
, ZnO, Li2O, Na2O, K2O, MnO
It may contain at least one oxide such as 2, BO3/2, etc.

[0020] Various compounds such as oxides (including composite oxides), carbonates, sulfates, chlorides, and fluorides can be used as raw materials for producing the above glass composition. All you have to do is let it happen. In the case of the circuit board of the present invention, the resin is reinforced with a reinforcing material made of fibers of the above-mentioned glass composition, and a printed circuit is built into the resin. Glass fiber reinforcement improves the mechanical strength and dimensional stability of printed circuit boards.

[0021] The shape of the glass fiber reinforcing material includes not only a cross shape but also a mat shape and a simple filament shape. In the case of cloth or mat, the fiber diameter is usually 0.
A material having a thickness of about 5 to 20 μm and a thickness of about 15 μm to 1.5 mm is used. In the case of filaments, the fiber diameter is usually 2 to 5.
0 μm and a length of about 20 to 300 μm are used.

The resin to be composited with the reinforcing material is not particularly limited, but in applications in the high frequency range, resins with low high frequency loss (
Low tan δ) resins are preferred, such as PPO (polyphenylene oxide) resins, fluororesins (e.g., Teflon: polyfluoroethylene resins such as DuPont's trade name), polycarbonate, polyethylene, polyethylene terephthalate, polypropylene, polystyrene, etc. Can be mentioned. The dielectric constant εr of these resins is usually about 2.0 to 3.2. Resins with higher dielectric constants (for example, epoxy resins, polyester resins, polyvinylidene fluoride, phenol resins, etc.) are preferable in terms of dielectric constant, but have large dielectric losses and are not particularly suitable for high frequencies.

[0023] Printed circuit boards usually have a thickness of 0.
It is about 1-2 mm, and the ratio (volume ratio) of resin and reinforcing material is usually resin: 30-95% by volume, reinforcing material: 5-7
It is 0% by volume. When manufacturing printed circuit boards,
For example, a glass cloth is impregnated with a resin varnish prepared in advance and dried, and then multiple pieces of the resulting resin-impregnated cloth are laminated and metal foil is placed on the surface (if necessary). , to be molded under heat and pressure using a mold. Then, as shown in FIG. 1, a printed circuit board 4 is formed by combining resin 2 with glass cloth 1 and having metal foil 3 on the surface.
is completed.

[0024]

[Operation] The glass composition of the present invention contains 40% of SiO2.
~65 mol%, 20-45 mol% of at least one of MgO, CaO, SrO and BaO, 5-25 mol% of at least one of TiO2 and ZrO2, N
The composition includes 0.5 to 15 mol% of bO5/2, and the total amount of these oxides is 85 mol% or more.

Therefore, this glass composition and a circuit board using a reinforcing material made of fibers of the glass composition have the following characteristics. First, the glass composition and reinforcing material have a high dielectric constant (1 MHz, 25°C) of 9 or more, and have a low dielectric loss (1 MHz, 25°C), that is, tan.
Low loss of δ0.6% or less, and 100MH
Even in the high frequency range of z, the above-mentioned dielectric constant and dielectric loss change slightly, and the material has excellent high frequency dielectric properties. Furthermore, it has excellent chemical durability (acid resistance, alkali resistance, water resistance) (
(Much superior to E-glass), there is no problem of damage caused by chemical treatment during processing. Further, there are no problems such as toxicity caused by lead-based glass containing a large amount of PbO.

As for the glass composition, since the devitrification temperature is below the temperature at which the melt viscosity becomes 102.5 poise, it is suitable for fiberization and can be used as a glass fiber for reinforcing materials. Since the glass cloth has a high temperature of about 600° C. and the primary binder removal process can be carried out appropriately during cloth formation, it can be used as an appropriate glass cloth useful as a reinforcing material. The circuit board according to the present invention has a structure in which the dielectric properties are enhanced by a reinforcing material, and not a structure in which the dielectric properties are enhanced by high relative permittivity inorganic particles, and therefore has good long-term reliability.

[0027]

[Examples] Examples and comparative examples will be explained below. "Examples and comparative examples of glass compositions" - Examples 1 to 2
5 and Comparative Examples 1 and 2 - Glass composition raw materials were prepared to have the compositions shown in Tables 1 to 3, placed in a platinum crucible, and heated (4 hours, 1500° C.) to melt. In addition, as raw materials, SiO2 is used for SiO2, MgO, CaO,
Carbonate is used for SrO and BaO, anatase type TiO2 is used for TiO2, ZrO2 is used for ZrO2,
For NbO5/2, a primary reagent of NbO5/2 was used.

Next, the melt was poured onto a carbon plate, formed into a plate shape, and annealed to obtain a plate glass. The following data were obtained for the sheet glass of each Example and Comparative Example. -Relative permittivity and dielectric loss- First, a portion of the obtained sheet glass was cut and polished to prepare a sample for dielectric property evaluation. Next, gold electrodes were deposited on both sides of this sample, and the relative dielectric constant and dielectric loss (dielectric loss tangent) were measured using an impedance analyzer. The measurement frequencies were 1 MHz and 1 GHz, and the temperature was 25°C.

-102.5 Poise Temperature - A part of the plate glass was melted and the viscosity of the melt was measured by the platinum ball pulling method to determine the 102.5 poise temperature. -Devitrification temperature- A part of the plate glass is made into a powder of 297 to 500 μm, then put into a platinum boat and kept in an electric furnace with a temperature gradient for 16 hours, then allowed to cool in the air, and the position where devitrification appears is determined under a microscope. It was measured by

- Suitability for making fibers - The remainder of the plate glass is crushed and placed in a platinum bushing, the platinum bushing is directly energized to melt the glass, the bushing temperature is set at 102.5 poise, and the bottom of the bushing is Glass fiber was obtained by pulling it out through a small hole (nozzle) and winding it up.

The above data are shown in Tables 1-6. In the above embodiments, glass fibers were obtained by forming sheet glass and then remelting it, but glass fibers may be obtained directly from the initial melt. Glass fibers can likewise be obtained. For mass production, it is appropriate to obtain the glass fibers directly from the initial melt.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

[Table 3]

[0035]

[Table 4]

[0036]

[Table 5]

[0037]

[Table 6]

[0038] Although all of the examples were able to be made into fibers,
Comparative Example 1 contains too much TiO2 and ZrO2 and does not contain NbO5/2, and Comparative Example 2 contains too much NbO2 and ZrO2.
Since it did not contain 5/2, it could not be made into fibers. 102
．． 5 (316) Poise temperature and devitrification temperature data well support the presence or absence of fiberization suitability. Note that the dielectric properties of the examples are good including in the high frequency range.

"Examples and Comparative Examples of Printed Circuit Boards" - Examples A to E and Comparative Examples A and B - Glass cloth was obtained by a conventional method using the fibers obtained from the glass composition of Example 3. Ta. This glass cloth is a plain weave glass cloth, thickness: 100 μm, fiber diameter: 7 μm, weaving density: 25
There are 60 vertical lines and 58 horizontal lines per mm.

For comparison, glass cloths using lead-based glass and E glass having the following compositions were also produced. "Lead glass" Composition PbO: 41.2 mol%, SiO2: 55.
3 mol%, B2 O3: 2.8 mol%, K2 O: 0
．． 7 mol% dielectric constant 1MHz: 13.0, 1GHz
:12.9 dielectric loss 1MHz: 0.09%, 1GH
z: 0.54% "E glass" Composition SiO2: 57.9 mol%, Al2 O3
:8.7 mol%, B2O3: 7.3 mol%, CaO
:24.2 mol%, MgO: 1.6 mol%, K2O:
0.3 mol% dielectric constant 1MHz: 6.5, 1GHz
:6.5 dielectric loss 1MHz: 0.15%, 1GHz
: 0.28% On the other hand, a resin varnish was prepared by adding 150 parts by volume of trichlene to 100 parts by volume of the PPO resin and stirring to completely dissolve the PPO resin.

[0041] Next, a glass cloth was impregnated with the resin varnish and then dried. The amount of impregnation was adjusted so that the volume ratio of PPO resin and glass cloth was as shown in Tables 4 and 5. The varnish-impregnated glass cloth thus obtained was
Copper foil (thickness 17 μm) was placed on the top and bottom of the stack, and the temperature was 25
Molding was carried out under the conditions of 0° C., pressure of 33 kg/cm 2 , and 10 minutes to obtain a printed circuit board with copper foil on both sides.

The relative permittivity and dielectric loss of the substrates of Examples and Comparative Examples were measured. The measurement results are shown in Tables 7 and 8.

[0043]

[Table 7]

[0044]

[Table 8]

As shown in Tables 7 and 8, the printed circuit board of Example A has a lower dielectric loss at 1 GHz than that of Comparative Example A using lead glass, and has a lower dielectric loss than that of Comparative Example A using E glass. It can be clearly seen that the dielectric constant is higher than that of the substrate B, making it suitable as a circuit board for high frequency range.

[0046]

Effects of the Invention As described above, the glass composition of the present invention contains 40 to 65 mol% of SiO2, MgO, Ca
At least one of O, SrO and BaO is 20 to 4
5 mol%, at least one of TiO2 and ZrO2 from 5 to 25 mol%, and NbO5/2 from 0.5 to 15 mol%.
It has a composition in which the total amount of these oxides is 85 mol% or more, has a high dielectric constant (9 or more), is suitable for fiberization, has excellent high frequency dielectric properties, and has excellent chemical durability. It is suitable as a reinforcing material for circuit boards.

Since the circuit board of the present invention has enhanced dielectric properties with the reinforcing material made of fibers of the glass composition having the above composition, it has excellent high frequency dielectric properties and is a useful board with high long-term reliability. ing.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing a configuration example of a printed circuit board according to a fourth aspect of the invention.

[Explanation of symbols]

1 Glass cloth (reinforcing material) 2 Resin 3 Metal foil 4 Printed circuit board

Claims (4)

[Claims] Claim 1: 40 to 65 mol% of SiO2, Mg
20 to 45 mol % of at least one of O, CaO, SrO and BaO, 5 to 25 mol % of at least one of TiO2 and ZrO2, and 0.5 mol % of NbO5/2.
5 to 15 mol% each, the total amount of these oxides is 85 mol% or more, and the dielectric constant (1 MHz, 25 ° C.
) A glass composition having a fiberization suitability of 9 or more. Claim 2: The content of SiO2 is 46 to 60 mol%, the content of at least one of MgO, CaO, SrO, and BaO is 25 to 40 mol%, and the content of at least one of TiO2 and ZrO2 is 7 to 24 mol%. %, the content of NbO5/2 is 1 to 10 mol%. [Claim 3] MgO, CaO, SrO and BaO
The content of at least one of 28 to 35 mol%, Nb
The glass composition according to claim 2, wherein the content of O5/2 is 2 to 9 mol%. 4. A circuit board comprising a resin reinforced with a reinforcing material made of fibers of the glass composition according to claim 1.