JP2000234239A - Glass cloth and printed circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain inexpensive glass cloth for printed circuit boards capable of providing circuit boards correspondable to low dielectric constant and high frequency property required for speeding-up of arithmetic processing and excellent in drill processing property by using a glass having low dielectric constant as glass different from characteristics which it originally has, capable of uniformly expressing newly obtainable characteristics by combining different kinds of glass yarns to make glass fiber uniform and especially being different kind. SOLUTION: In this glass cloth constituted of warp and weft, either one of warp and weft is E glass and the other is glass different from E glass and glass yarn composed of the glass is flattened and further, average space between adjacent glass yarn bundles is <=10% based on average yarn bundle width. It is especially preferable that weft comprises a glass different from E glass and the glass comprises D glass among glasses different from E glass.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a printed wiring board used in the fields of electronics and electricity. In particular, the present invention relates to an improvement in a high-density printed wiring board and a glass cloth used for the wiring board.

[0002]

2. Description of the Related Art In recent years, with the era of advanced information technology in which computers and communications are integrated, the amount of information has dramatically increased, the speed of computer processing has been increased, and the use of higher frequencies and smaller sizes due to the spread of portable communication devices have increased. As a result, the characteristics required for a printed wiring board are also diversified, and new characteristics different from the past are required for the glass base material, resin, and the like as the substrate material. In particular, in order to realize high-density wiring of a printed wiring board and high-speed operation processing of a computer, it is necessary to reduce the dielectric constant of the printed wiring board and to cope with high-frequency characteristics. The relative permittivity of a printed wiring board is approximately expressed as the sum of the relative permittivity of the base material that constitutes it and the volume percentage of the relative permittivity of the resin itself. Must have a low dielectric constant.

In order to cope with high frequency characteristics, it is necessary to lower the dielectric loss tangent of the substrate. Further, in recent years, with the increase in frequency, there is a concern about the influence of the woven structure of the glass cloth. That is, the glass cloth generally has a plain weave structure in which warp yarns and weft yarns alternately float and sink, in which case, a portion where the yarns overlap, a portion where one of the yarns exists, a basket hole and the like. It is anticipated that there will be a mixture of the three states of the so-called glass-free portion surrounded by the warp and weft yarns, and this structure will cause various problems in the microscopic region. For example, there is a problem that the impedance of the substrate in the high frequency region cannot be matched.

Conventionally, non-alkali glass fibers called E glass have been widely used for glass fiber reinforced printed wiring boards because of their good electrical insulation, easy fiber, low cost and good workability. However, since the relative permittivity is 6 to 7, the relative permittivity of a printed wiring board when an epoxy resin, which is widely used as a binder, is about 5, which is necessary for high-speed arithmetic processing. Not compatible with relative permittivity. Further, in the high-frequency region, the E glass has a remarkably increased dielectric tangent, which causes problems such as signal attenuation. In order to obtain a substrate having a low dielectric constant and a low dielectric loss tangent, a glass having a low dielectric constant and a low dielectric loss tangent called D glass (JP-A-63-2831) has been developed. Compared to glass yarns, they are very brittle and have poor weaving properties. As a result, the yield increases as the quality decreases,
Glass cloth woven with only D glass yarn is very expensive. In addition, the D glass cloth has extremely poor drill wear, hole position accuracy, and the like, as compared with the laminated plate using the E glass cloth as a base material.

Therefore, by changing the glass composition,
Glasses with improved workability and the like (Japanese Patent Application Laid-Open No. 6-219780) have also been proposed, but are not preferred because they are not widely used and are expensive. Further, a glass cloth having a low dielectric constant and a low dielectric tangent (Japanese Patent Laid-Open No. 10-310967) has been proposed by combining an E glass thread with a different kind of low dielectric glass thread. Since it is not formed, it cannot cope with high-frequency characteristics, and the workability of the drill is also affected by the woven structure of the glass cloth, and the characteristics of abrasion and hole position accuracy are not sufficient.

[0006] Therefore, it is possible to cope with various characteristics required for the printed wiring board as described above, and in particular, it is possible to cope with low dielectric constant and high frequency characteristics of the substrate, and it is excellent in drillability and low cost glass cloth. The development of is desired.

[0007]

SUMMARY OF THE INVENTION According to the present invention, by combining different kinds of glass yarns to make the glass fibers uniform, it is possible to uniformly exhibit newly required properties different from the inherent properties. In particular, the use of low-dielectric-constant glass as a dissimilar glass makes it possible to obtain a substrate that has a low-dielectric constant required for high-speed arithmetic processing and that can respond to high-frequency characteristics. It is an object of the present invention to provide a glass cloth for a printed wiring board.

[0008]

Means for Solving the Problems As a result of diligent studies on the above-mentioned problems, the present inventors focused on the structure and structure of the glass yarn forming the glass cloth, and formed a glass different from the E glass out of the warp and the weft. E glass is used for either one of them, and furthermore, the distribution of the glass thread in the surface direction is made uniform, and specifically, the thickness and width of the thread bundle of the glass thread and the gap between adjacent thread bundles are limited. Compared with a substrate using a cloth or a cloth made of simple dissimilar glass as a base material, it has been found that characteristics different from those of the related art can be uniformly exhibited, and the present invention has been completed. In particular, by using D glass as a different kind of glass, it becomes possible to obtain a substrate having a low dielectric constant required for a printed wiring board,
We found that impedance matching, which is a concern at higher frequencies, is maintained by the uniformity of glass fibers, and that the drillability of the substrate is improved compared to conventionally used low-permittivity glass cloth. The invention has been completed. Furthermore, the warp yarn is made of E glass yarn having excellent weaving properties, and the weft yarn is made of a glass different from E glass, thereby preventing a decrease in quality due to friction of a reed or the like, greatly reducing the yield, and providing an inexpensive glass cloth. Finding what you can get,
The present invention has been completed.

That is, the present invention provides a glass cloth comprising a warp yarn and a weft yarn, wherein one of the warp yarn and the weft yarn is E glass, and the other is a glass different from the E glass, and is composed of the glass. Provided is a glass cloth in which glass yarns are flattened and the average gap between adjacent glass yarn bundles is 10% or less of the average yarn width of the yarn bundles. Further, (however, the flattened glass yarn referred to herein is defined as a yarn having an average thickness of 70% or less and an average yarn width of 20% or more as compared with a normal glass yarn.) It is also characterized in that the weft yarn is a glass different from E glass. Another characteristic is that, out of glass different from E glass, the glass is D glass. Further, there is provided a printed wiring board using the glass cloth described in any of the above as a base material.

Hereinafter, the present invention will be described in detail. (i) Features of the glass cloth of the present invention 1) In order to uniformly exhibit characteristics different from those originally possessed by the glass cloth, not only a glass different from E glass but also a uniform glass Is important. That is, in the glass yarn different from the E glass, the gap between adjacent yarn bundles is equalized to 10% or less, preferably 5% or less of the cross-sectional width of the yarn bundle, and more preferably the surface direction is made uniform until there is no gap. Is desirable.

2) In order to make the glass cloth uniform in the thickness direction, a glass yarn different from E glass is flattened, and the average thickness of the yarn bundle is smaller than the average thickness of ordinary glass yarn. It is desirable to satisfy a relationship of 70% or less, preferably 60% or less. (The normal glass thread here is E
E corresponding to the same thread thickness as a glass thread different from glass
Shows a glass thread. The reason is that if the flatness is larger than 70%, the glass component existing in the thickness direction at the center of the yarn bundle increases,
This is because uniformity in the thickness direction cannot be achieved, and uniform development of new characteristics and adverse effects on drill workability and the like.

3) According to the present invention, a combination of different kinds of glass exhibits characteristics different from those of the conventional E glass cloth.
By using glass, a substrate having a low dielectric constant and a low dielectric loss tangent can be obtained. Further, in this case, as an effect of the uniform glass, the impedance matching of the substrate in the high frequency region is maintained.

4) Warp yarns constituting the glass cloth
Or by using E-glass for one of the weft threads,
Increased cost, improved drill workability, and improved weaving
By making the excellent E-glass yarn into warp yarn,
Prevent quality deterioration due to rubbing and greatly reduce yield
Thus, a cheaper and higher quality glass cloth can be obtained. Departure
The D glass used for the light glass cloth is described in, for example,
As disclosed in JP-A-63-2831, weight percent
At the rate_TwoO 70.0-80.0%, Al_TwoO_Three
0 to 2.0%, B_TwoO_Three 15.0-21.5%, Mg
O 0-1.0%, CaO 0-2.0, Li_TwoO 0
~ 2.0%, Na_TwoO 0-3.0%, K_TwoO 0
3.0%, Li_TwoO + Na_TwoO + K_TwoO 2.0-5.
It consists of 0%. In addition, the glass cloth of the present invention
The E-glass used for, for example, by weight percentage, Si_Two
O 52.0-56.0%, Al_TwoO_Three12.0-1
6.0%, B_TwoO _Three 8.0-13.0%, MgO 0
~ 6.0%, alkali metal oxide (R_TwoO) 0-3.
It consists of 0%.

(Ii) Production of glass cloth: 1) To obtain the glass cloth of the present invention, the thickness of the yarn,
Although the filament diameter and the number of twists of the yarn are not particularly limited, the total number of filaments constituting the glass yarn is 400
It is desirable not to exceed the book. 2) The filament diameter is also preferably not more than G yarn, preferably not more than E yarn in nominal diameter. 3) Further, the twist of the glass thread is usually 0.7 to
The number of twists of 1.0 turns / inch may be reduced, that is, the number of twists of the glass yarn may be set to 0.5 times / inch or less, preferably 0.3 to 0 times / inch. The reason for this is that, by adopting the above-described glass yarn configuration, the yarn width is easily expanded, and a structure in which the filaments are uniformly distributed in the thickness direction of the yarn bundle is easily formed. 4) In addition, in order to obtain the glass cloth of the present invention, for example, the yarn is flattened by performing opening by water pressure, opening by high-frequency vibration using a liquid medium, processing by pressing with a roll, or the like. As a result, the yarn width increases, the cross-sectional shape of the yarn itself approaches the shape of a flat plate from an elliptical shape, the distribution of the glass fibers in the glass cloth becomes more uniform, and the same effect as that of lower twisting of the yarn can be obtained. 5) Further, processing in a state in which an organic substance such as a lubricant is attached to the glass thread, or a combination of these methods is more effective.

(Iii) Production of laminated board: 1) The printed wiring board of the present invention may be prepared by a conventional method. For example, a glass cloth of the present invention is impregnated with a matrix resin such as an epoxy resin. A resin-impregnated prepreg is prepared, and a plurality of the prepregs are laminated, or a plurality or one of the prepregs is laminated on an inner layer core plate, and is subjected to heat and pressure molding. As the resin used for the printed wiring board, epoxy resin, unsaturated polyester resin,
Thermosetting resins such as polyimide resin, BT resin, and cyanate resin; thermoplastic resins such as PPO resin, polyetherimide resin, and fluororesin; and combinations of these resins. 2) Further, a resin in which an inorganic filler such as aluminum hydroxide or the like and other known additives such as an elastomer are mixed in the resin may be used.

[0016]

The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the invention thereto. The physical properties of the glass cloth, the thickness and width of the cross section of the yarn bundle of the glass cloth, the method of preparing a laminate using the glass cloth, and the test method in the examples and comparative examples were measured by the following methods. Measurement method for physical properties of glass cloth: Measured according to JISR3420. Measuring method of thickness and width of yarn bundle cross section: Glass cloth is embedded in cold-cured epoxy and polished to cut out the yarn bundle cross section of different glass, and an electron microscope [S, manufactured by Hitachi, Ltd.
-570], the thickness, width and gap of the yarn bundle cross section shown in FIG. 1 were measured.

A method for producing a laminate for a printed wiring board:
A glass cloth was impregnated with an epoxy resin varnish and dried to obtain a prepreg. Eight prepregs are laminated, and a copper foil having a thickness of 12 μm is laminated on top and bottom of the prepregs.
The laminate was obtained by heating and pressing at kg / cm ² . Evaluation of processability of printed wiring board: A laminate was prepared by the method described above, and the processability was evaluated by the following method. <Workability evaluation conditions> Test piece: two laminated boards Drill: PDS030 [manufactured by Toshiba Tungaloy Co., Ltd.] Drill diameter: 0.3 mm Drill rotation speed: 70,000 rpm Feed speed: 1.4 m / min This plate: 0.15mm aluminum disc: 1.6mm bake

<Evaluation method> (1) Evaluation of drill abrasion The abrasion state of the drill tip when cutting each number of holes (500 holes and 1000 holes) was observed with a microscope.
During abrasion, x: Large abrasion was evaluated. (2) Evaluation of Hole Position Accuracy The through hole on the back surface of the two stacked sheets and the deviation from the set drilling position were measured with a hole position accuracy measuring device [Takeuchi Seisakusho Co., Ltd. pixel].

(Embodiment 1) As a glass cloth, a warp yarn is ECE225 which is an E glass yarn having a relative dielectric constant of 6.5.
1/0 1.0Z, the weft yarn uses DCE225 1/0 1.0Z which is a D glass yarn having a relative dielectric constant of 4.2,
In an air jet loom, a glass cloth is woven at a woven density of 60 warps / 25 mm and 57 wefts / 25 mm, and the obtained greige fabric is flattened by high-pressure water flow (processing pressure: 30 kg / cm ² ). The method was adopted.
Thereafter, high-temperature desizing was performed at 400 ° C. for 24 hours. Subsequently, SZ6032 which is a silane coupling agent is used as a surface treatment.
Example 1 having a treatment liquid using [Toray Dow Corning Co., Ltd.], immersing a glass cloth, squeezing, drying at 120 ° C. for 1 minute, weighing 104 g / m ² , and having a thickness of 0.105 mm. Glass cloth was obtained. Using this glass cloth, a laminate was prepared by the method described above.

(Example 2) As a glass cloth, ECE225 which is an E glass yarn having a relative dielectric constant of 6.5 was used for the warp yarn.
1/0 1.0Z, the weft yarn uses DCE225 1/0 1.0Z which is a D glass yarn having a relative dielectric constant of 4.2,
In an air jet loom, a glass cloth is woven with a woven fabric density of 60 warp yarns / 25 mm and weft yarns 47 yarns / 25 mm, and the obtained greige is opened by a high-pressure water flow (processing pressure 3).
0 kg / cm ² ) method. Thereafter, high-temperature desizing was performed at 400 ° C. for 24 hours. Subsequently, surface treatment was performed in the same manner as in Example 1 to obtain a glass cloth of Example 2 having a weight of 95 g / m ² and a thickness of 0.088 mm. Using this glass cloth, a laminate was prepared by the method described above.

(Embodiment 3) As a glass cloth, a warp yarn is ECE225 which is an E glass yarn having a relative dielectric constant of 6.5.
1/0 1.0Z, and weft made of DCE225 1/0 1.0Z, which is a D glass having a relative dielectric constant of 4.2, was woven in an air jet loom with 47 warps / 25 mm and 60 wefts / 25 mm. Weave glass cloth with density,
The obtained greige fabric is opened by high-pressure water flow (processing pressure 30k
g / cm ² ) method. Then, at 400 ° C. for 24 hours
High temperature desizing for hours. Subsequently, surface treatment was performed in the same manner as in Example 1 to obtain a glass cloth of Example 3 having a weight of 105 g / m ² and a thickness of 0.100 mm. Using this glass cloth, a laminate was prepared by the method described above.

(Comparative Example 1) ECE2 which is E glass having a relative dielectric constant of 6.5 was used for warp and weft as glass cloth.
Using 25 1/0 1.0Z, in an air jet loom, 60 warps / 25 mm, wefts 57/25 mm
Weave a glass cloth with a fabric density of
C. for 24 hours. Subsequently, a surface treatment was performed in the same manner as in Example 1, and the weight was 105 g / m ² and the thickness was 0.094.
mm of the glass cloth of Comparative Example 1. Using this glass cloth, a laminate was prepared by the method described above.

(Comparative Example 2) As a glass cloth, E-glass ECE225 1/0 having a relative dielectric constant of 6.5 was used for the warp yarn.
For the 1.0Z and the weft, DCE2251 / 0 1.0Z, which is a D glass having a relative dielectric constant of 4.2, is used. In an air jet loom, 60 warps / 25 mm, 57 wefts /
A glass cloth was woven at a woven fabric density of 25 mm, and the obtained green fabric was subjected to high-temperature desizing at 400 ° C. for 24 hours. Subsequently, surface treatment was performed in the same manner as in Example 1 to obtain a glass cloth of Comparative Example 2 having a weight of 104 g / m ² and a thickness of 0.101 mm. Using this glass cloth, a laminate was prepared by the method described above. The results are summarized in Table 1 below.

[0024]

[Table 1] (Note) The normal yarn defining flattening was the weft yarn of Comparative Example 1.

[0025]

The use of the printed wiring board having the glass cloth as a base material of the present invention makes it possible to express new characteristics uniformly. Particularly, when combined with D glass, low cost and low cost can be achieved. It is possible to obtain a substrate having a low dielectric constant and a high frequency, and to provide a printed wiring board excellent in drill workability.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating the thickness and width of a cross section of a warp or weft yarn bundle of a glass yarn constituting a glass cloth.

[Explanation of symbols]

 A Thread bundle cross-section width B Thread bundle cross-section thickness C Thread bundle gap

Continued on the front page F term (reference) 4F100 AB17B AB33B AG00A AK53A BA02 DG12A DG18A DH01A GB43 JG05 JL01 JL02 4L048 AA00 AA03 AB00 AC00 BA02 CA00 CA15 DA43 EA01 EB00

Claims (4)

[Claims] 1. A glass cloth comprising a warp and a weft, wherein one of the warp and the weft is E glass, the other is a glass different from the E glass, and the glass thread formed of the glass is flat. A glass cloth, wherein the average gap between adjacent glass yarn bundles is 10% or less of the average yarn width of the yarn bundle. 2. The glass cloth according to claim 1, wherein the weft is glass different from E glass. 3. The glass according to claim 1, wherein said glass is D glass among glasses different from E glass.
Glass cloth as described. 4. A printed wiring board using the glass cloth according to claim 1 as a substrate.