JPH04367537A - Glass composition and substrate for circuit - Google Patents

Abstract

PURPOSE:To provide a glass composition having improved fiber-forming adaptability, excellent dielectric characteristics even in a high-frequency band and good chemical durability. CONSTITUTION:A glass composition comprising 40-65mol% SiO2, 20-45mol% at least one of CaO, SrO and Bad, 5-25mol% at least one of TiO2 and ZrO2, 0.5-15mol% NbO5/2 and 0.5-15mol AlO3/2 and >=85mol total of these oxides, having >=9 dielectric constant (1MHz, 25 deg.C) and fiber-forming adaptability.

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 whose primary binder is not removed sufficiently may 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 provides a glass composition that has good suitability for forming into fibers, has excellent dielectric properties even in a high frequency range, and is rich in chemical durability. The first problem is to provide a circuit board that has excellent dielectric properties even in a high frequency range and has high long-term reliability.

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.

[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.
An appropriate amount of NbO5 is added to the O2-ZrO2-based glass composition.
/2 is added, the devitrification temperature and the melt viscosity are 102
．． It was found that this is effective in preventing the temperature from exceeding 5 poise (316 poise).

However, it has been difficult to provide sufficient fiberization suitability just by adding NbO5/2. This is because the difference between the devitrification temperature and the temperature at which the melt viscosity becomes 102.5 poise does not become sufficiently large. If the difference between the devitrification temperature and the melt viscosity is 102.5 poise temperature, the temperature change inside the bushing will cause a partial drop in the glass melt temperature, which will cause crystallization due to devitrification and cause thread breakage. Therefore, it is very difficult to control fiberization, and its suitability for fiberization cannot be said to be sufficient.

[0013] Therefore, the inventors continued their studies and added an appropriate amount of AlO3/2 in addition to NbO5/2.
We were able to obtain the knowledge that adding . That is, SiO2 -BaO-
TiO2-ZrO2-based glass compositions are mainly composed of SiO2-based cristobalite crystals and BaO-TiO due to devitrification within the composition range that can ensure the necessary dielectric properties.
2-ZrO2-based crystals are precipitated, but the addition of an appropriate amount of NbO5/2 results in the precipitation of the latter BaO-TiO2
Although the devitrification temperature is lowered to suppress the precipitation of -ZrO2-based crystals, the precipitation of the former SiO2-based cristobalite crystals cannot be suppressed completely, and there is a limit to the extent to which the devitrification temperature can be lowered. Therefore, by adding an appropriate amount of AlO3/2 at the same time, it is possible to sufficiently suppress the precipitation of SiO2-based cristobalite crystals, further lowering the devitrification temperature, and also increasing the melt viscosity. It was discovered that the difference from the 102.5 poise temperature can be made larger. Addition of AlO3/2 alone without NbO5/2 does not bring the devitrification temperature below 102.5 poise temperature.

[0014] Therefore, in order to solve the first problem,
The glass composition of the invention according to claim 1 contains 4 SiO2
0 to 65 mol%, 20 to 45 mol% of at least one of CaO, SrO and BaO, TiO2 and Zr
5 to 25 mol% of at least one of O2, NbO5
/2 0.5 to 15 mol%, AlO3/2 0.5
~15 mol% each, the total amount of these oxides is 85 mol% or more, and the dielectric constant (1 MHz, 25 ° C.)
The glass composition of the invention according to claim 2 has a structure having a fiberization suitability of 9 or more, and further has a SiO2 content of 46 to 60 mol% and a content of at least one of CaO, SrO, and BaO. 25-40 mol%, TiO2
and the content of at least one of ZrO2 is 7~
24 mol%, NbO5/2 content is 1-10 mol%
, the content of AlO3/2 is 1 to 10 mol%.

[0015] In order to solve the second problem,
The circuit board according to the third 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 the first or second aspect. This invention will be explained in detail below. Since the glass composition of the present invention has the above composition, it has a dielectric constant of 9 or more (1
MHz, 25° C.) and good suitability for fiberization.

[0016] Specific dielectric constant (1 MHz, 25°C): High dielectric constant of 9 or more. ■ Dielectric loss (1MHz, 25
℃), that is, the loss is low with a tan δ of 0.6% or less. ■
Even in the high frequency range of 100 MHz, the above-mentioned dielectric constant and dielectric loss change slightly, and the material has excellent high frequency dielectric properties. ■
Rich in chemical durability (acid resistance, alkali resistance, water resistance).

■ The devitrification temperature and the melt viscosity are 102.5.
It is much lower than the temperature at which it becomes poise, and has extremely good fiberization suitability. The temperature difference between the devitrification temperature and the 102.5 poise temperature is more than 85°C. ■ 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 4
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 CaO, SrO and BaO: 20 to 45 mol% (more preferably 25 to 40 mol%)
(mol %) CaO, SrO and BaO act as modifying ions of the glass structure and facilitate the melting. Moreover, the combined use results in a decrease in the devitrification temperature. CaO, SrO and B
aO functions to increase the dielectric constant. If it is less than 20 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. If it exceeds 45 mol %, 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%) TiO2 and ZrO2 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. AlO3/2: 0.5 to 15 mol% (more preferably 1 to 10 mol%) AlO3/2 is a component that forms the skeleton of glass,
This results in a decrease in devitrification temperature and an increase in melt viscosity. 0.5
If it is less than 15 mol %, the necessary addition effect will not be obtained, and if it exceeds 15 mol %, the dielectric constant will decrease and the viscosity of the glass will increase excessively, making it difficult to form into a melt and to form into fibers.

[0022] If the total amount of the oxides is less than 85 mol%, it will be difficult to ensure a dielectric constant of 9 or more, or it will be difficult to ensure the necessary suitability for forming fibers. Note that the glass composition of the present invention contains Li2O,
Na2O, K2O, ZnO, MnO2, TaO5
/2, BO3/2, LaO3/2, CeO2
It may contain at least one oxide such as.

[0023] 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.

The shape of the glass fiber reinforcing material includes, in addition to the cross shape, the mat shape and the 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.

[0026] The printed circuit board usually has 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.

[0027]

[Operation] The glass composition of the present invention contains 40% of SiO2.
~65 mol%, 20-45 mol% of at least one of CaO, SrO and BaO, TiO2 and ZrO
2 at least one of 5 to 25 mol%, NbO5/
2 from 0.5 to 15 mol%, AlO3/2 from 0.5 to 15 mol%
15 mol% each, bringing the total amount of these oxides to 8
The composition is 5 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 far lower than the temperature at which the melt viscosity becomes 102.5 poise, it has excellent fiberization suitability and can be easily made into glass fiber for reinforcing materials. In addition, since the strain point is as high as about 600° C. and the primary binder removal process can be performed appropriately during cloth formation, it can be made into an appropriate glass cloth useful as a reinforcing material.

Regarding the circuit board according to the present invention,
It 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, so long-term reliability is also good.

[0031]

[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 to 4 - Glass composition raw materials were prepared to have the compositions shown in Tables 1 to 3, and were placed in a platinum crucible and heated (4 hours, 1500° C.) to melt. The raw materials used were SiO2 for SiO2, carbonate for CaO, SrO and BaO, anatase TiO2 for TiO2, ZrO2 for ZrO2, and NbO5.
/2 is NbO5/2 primary reagent, AlO3/2
A primary reagent of AlO3/2 was used for each.

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 fiberization- 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 1-3. 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.

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

[Table 3]

In the case of the example, the difference between the devitrification temperature and the 102.5 poise temperature was larger than that in Comparative Examples 1 and 2, and the sample had sufficient suitability for fiberization, so it could be easily fiberized. In the case of Comparative Examples 1 and 2, it was possible to form fibers, but the difference between the devitrification temperature and the 102.5 poise temperature was small, and strict temperature control was required to prevent devitrification during the work. The work was not easy. Comparative Examples 3 and 4 are N
Since it did not contain bO5/2 and had a devitrification temperature higher than 102.5 poise temperature, it could not be made into fibers.

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 - Using the fibers obtained from the glass compositions of Example 2, glass cloth was obtained by a conventional method. This glass cloth is a plain-woven glass cloth, with a thickness of 100 μm, a fiber diameter of 7 μm, and a weaving density of 25 mm, with 60 fibers lengthwise and 58 fibers widthwise.

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.

[0042] 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 4 and 5.

[0044]

[Table 4]

[0045]

[Table 5]

As shown in Tables 4 and 5, 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 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.

[0047]

Effects of the Invention As described above, the glass composition of the present invention contains 40 to 65 mol% of SiO2, CaO, Sr.
20 to 45 mol% of at least one of O and BaO
, TiO2 and ZrO2.
~25 mol%, NbO5/2 0.5-15 mol%,
The composition contains 0.5 to 15 mol% of AlO3/2, and the total amount of these oxides is 85 mol% or more,
It has a high relative dielectric constant (9 or more), ensuring good suitability for forming into fibers, and also has excellent high-frequency dielectric properties and chemical durability, making it suitable as a reinforcing material for circuit boards. ing.

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

[Brief explanation of drawings]

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

[Explanation of symbols]

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

Claims (3)

[Claims] Claim 1: 40 to 65 mol% of SiO2, 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%.
glass containing 0.5 to 15 mol% of AlO3/2, the total amount of these oxides being 85 mol% or more, and having a dielectric constant (1MHz, 25°C) of 9 or more and suitability for fiber formation. Composition. 2. The content of SiO2 is 46 to 60 mol%, the content of at least one of CaO, SrO and BaO is 25 to 40 mol%, and the content of TiO2 and ZrO2 is 25 to 40 mol%.
The content of at least one of 7 to 24 mol%, NbO
The glass composition according to claim 1, wherein the content of 5/2 is 1 to 10 mol%, and the content of AlO3/2 is 1 to 10 mol%. 3. A circuit board comprising a resin reinforced with a reinforcing material made of fibers of the glass composition according to claim 1 or 2.