JPH09316749A - Glass cloth - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a glass cloth which is reduced in irregularity of dimensional variation of the substrate plate, particularly having reduced anisotropy in the warp and weft directions in the process for producing printed circuit boards from copper-clad laminates by specifying the interval between glass fiber strands in the warp and weft directions as well as specifying the warp strands and/or the weft strands. SOLUTION: The interval (x) between glass fiber strands in both warp and weft directions is controlled less than 0.1mm on the average, preferably less than 0.1mm at most, while the warp strands and/or the weft strands are adjusted to (G75 I/O or G68 I/O according to JIS R341. In the corrective operation for scale factor, no sophisticated technique is not required and the automatic insertion of the parts can be smoothly done with reduced number of part-positioning marks.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass cloth for laminated boards for printed wiring boards used in the fields of electricity and electronics.

[0002]

2. Description of the Related Art Generally, a printed wiring board is made by a known processing method such as drilling holes, washing holes, electroless copper plating, etc. on a copper-clad laminate. Is generally known to change. The copper-clad laminate used here is manufactured by laminating and molding a prepreg obtained by impregnating a glass cloth with a thermosetting resin such as an epoxy resin by a press machine. The glass cloth used for this is JIS R3414. Those shown in are commonly used.

[0003] The glass cloth to be used is selected in consideration of the configuration of the laminated plate and the like in order to reduce the dimensional change, warpage, and twist of the laminated plate. It is not a fundamental solution,
A glass cloth having a new configuration is desired. For example, since the distance between the adjacent glass yarns constituting the glass cloth is wide, a large amount of resin is distributed in the gap between the yarns in the prepreg, and there is a variation in curing shrinkage of the resin. The yarn is easy to move due to the large spacing,
Or, there is a problem of variation in the dimensional change of the laminated plate due to unbalance due to the difference in weaving density in the vertical direction and the horizontal direction, and anisotropy in the vertical direction and the horizontal direction (hereinafter, anisotropy). .

As the circuit pattern becomes denser as recently, advanced technology is required for correcting the scale factor required for producing a negative of the circuit pattern or for forming a through hole. In particular, when the size of the work of the printed wiring board is large, many parts positioning marks are required.

On the other hand, a glass cloth specified in JIS standard is subjected to physical processing such as opening to expand the yarn bundle, and glass having the same weaving density in the vertical direction and the horizontal direction. Cross proposals have been made, but
None of them are sufficient and the problem has not been solved yet.

[0006]

SUMMARY OF THE INVENTION The present invention does not require a high-level technique for the scale factor correction work, and enables easy automatic insertion of parts with a small number of part positioning marks. To provide a glass cloth capable of reducing variation in dimensional change of a board during a process of producing a printed wiring board from a copper-clad laminate, and particularly reducing anisotropy in the vertical direction and the horizontal direction. It is in.

[0007]

As a result of various studies on the above problems, the present inventor found that a glass cloth suitable for a laminated board for a printed wiring board can be provided by devising a woven structure of the glass cloth. The present invention has been completed.

According to the present invention: In a glass cloth woven from a warp yarn and a weft yarn, a distance x between the glass yarn and the glass yarn constituting the glass cloth in the warp direction and the weft direction is 0.1 mm or less, and Either or both of the glass warp warp yarn and the weft yarn are designated in JIS R3413. Thread designation G75
A glass cloth which is 1/0 or G68 1/0 is provided (however, the distance between the yarns referred to here means the distance x shown in FIG. 1). It is also characterized in that the weaving shrinkage ratio of the glass yarns in the direction in which the number of the weaving glass yarns per unit length is large is higher than the weaving shrinkage ratio of the glass yarns in the direction in which the number of the weaving fibers is small. Another characteristic is that the ratio of the warp shrinkage ratio of the warp yarns to the weave shrinkage ratio of the weft yarns is 0.7 to 1.3.

Hereinafter, the present invention will be described in detail. The count here means the mass of the glass yarn per unit length as shown in JIS R3413, and the weaving shrinkage ratio was measured according to the weaving shrinkage ratio measuring method described in JIS L1096. By using the specific glass cloth of the present invention, it becomes possible to reduce the amount of the resin existing in the gaps between the glass yarns in the laminated plate using the glass cloth, and the number of the glass yarns and the weaving number of the glass yarns. The balance of shrinkage ratio can be optimized, and the variation in dimensional change of the laminated plate can be reduced without using glass cloth which has been increased by one step by physical processing such as opening processing, and the anisotropy is remarkably improved. I found that

The dimensional change of the laminated plate is governed by how the glass cloth as the base material suppresses the volume change such as curing shrinkage of the matrix resin, and the variation of the dimensional change is caused by the uneven distribution of the resin in the laminated plate. Dependent. Further, the anisotropy largely depends on the amounts of the glass yarns in the vertical direction and the horizontal direction, but also depends on the magnitude of the reinforcing effect in the plane direction of the glass yarn in each direction.

For example, even if the weaving density is high, if the yarn waviness is large, the reinforcing effect of the glass yarn is largely dispersed in the thickness direction, and the reinforcing effect in the plane direction, that is, the effect of suppressing the dimensional change of the laminated plate. Becomes smaller. Therefore, in order to reduce the dimensional change of the laminated plate, reduce the variation, and reduce the anisotropy, it is possible to increase the glass yarn amount in the vertical direction and the horizontal direction and reduce the gap between the glass yarns. It becomes necessary, and preferably, the relationship between the weaving density and the weaving shrinkage ratio of the yarn needs to be optimized.

(I) In order to bring out the effect of the present invention, the average gap x between the glass yarns in both the vertical direction and the horizontal direction is 0.
1 mm or less, preferably the maximum value is 0.1 mm
It is desirable that: Of course, it is most desirable that the lower limit of the gap x be 0 or a value close to 0 (claim 1). To measure the gap between glass yarns, embed the glass cloth in epoxy resin that cures at room temperature, grind out the cross section of the glass yarn, observe with an electron microscope, optical microscope, etc., and measure the length between the yarns. Obtained.

(Ii) Moreover, in particular, either or both of the warp yarn and the weft yarn of the glass yarn constituting the glass yarn are JI.
In the case where the yarn designated by S R3413 is called G75 1/0 or G68 1/0 and the yarn count is greater than 60, the thickness of the glass cloth made using the glass yarn becomes thick and the same plate thickness is obtained. The number of the glass cloths constituting the laminated board is less than that of the glass cloths prepared by using the yarn having the count less than 50 as in JIS R3413. Therefore, the non-uniform distribution of the resin in the glass cloth gap due to the number of laminated sheets cannot be compensated in the laminated plate, and the variation in the dimensional change of the laminated plate appears more significantly. Therefore, the effect of the present invention is more remarkable in the glass cloth using thick yarn (claim 1).

(Iii) Further, from the woven structure, even if the warp yarn and the weft yarn have the same weaving density, the weaving shrinkage ratios are not the same, so that the weaving shrinkage of the yarn in the direction of high weaving density is increased. As a result, it becomes possible to make the reinforcing effect in the laminate by glass yarns in both vertical and horizontal directions to the same degree. Similarly, it is expected to be effective in reducing warpage and twisting of laminated plates (claim 2).

(Iv) Furthermore, when the weaving density of the glass cloth is increased and, as a result, the cloth weight of the glass cloth is increased, the thickness of the glass cloth is generally increased. However, in a laminated board, especially a multilayer board, the thickness between layers is important, and an increase in the thickness of the glass cloth is not preferable. Generally, in the case of woven fabric, when the warp and weft shrinkage ratios are the same,
The thickness of the fabric approaches the value obtained by adding the thickness of the warp yarn and the thickness of the weft yarn, and as a result, the thickness of the fabric approaches the minimum value among cloths using the same type of yarn.

It is necessary that the ratio of the warp shrinkage ratio of the warp yarn to the weave shrinkage ratio of the weft yarn is 0.7 to 1.3, preferably 0.8 to 1.2 (claim 3). As a result, even if the cloth weight of the glass cloth increases, it is possible to create a glass cloth that maintains the thickness. When the ratio of the weaving shrinkage ratio of both is less than 0.7, the waviness of the weft yarn becomes significantly large, and when the ratio exceeds 1.3, the waviness of the warp yarn becomes significantly large, and as a result, In either case, the thickness of the glass cloth becomes thick, which causes a change in the thickness between the layers of the laminated plate, which is not preferable.

(V) Although glass called E glass (non-alkali glass) is usually used for the glass cloth of the laminated board used for the printed wiring board, D glass, S glass, high dielectric glass, etc. are used. However, the effect of the present invention is not impaired by the glass type. The laminated plate 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 to prepare a resin-impregnated prepreg, and a plurality of these are laminated, or It is obtained by laminating in combination with a resin impregnated prepreg made of a normal glass cloth, and heat-pressing.

When a glass cloth and a non-woven fabric are used in combination as the substrate, the object of the present invention can be achieved by using the glass cloth of the present invention in the surface layer. The resin used for the laminate is an epoxy resin,
Unsaturated polyester resin, polyamide resin, BT resin,
Examples thereof include thermosetting resins such as cyanate resins, thermoplastic resins such as PPO resins, polyetherimide resins, and fluorine resins, and mixed resins thereof. Further, a resin in which an inorganic filler such as aluminum hydroxide is mixed in the resin may be used.

[0019]

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 laminated plates in the examples were prepared by the following method, and the dimensional change was J
It was measured according to IS6481. Table 1 shows the measurement results. Method for producing laminated plate: The glass cloth of the present invention was impregnated with an epoxy resin and dried to obtain a prepreg. Four prepregs were laminated, copper foils of 35 μm were further laminated on the top and bottom, and heat and pressure were applied at 175 ° C. and 40 kg / cm ² to obtain a laminated plate.

(Example 1) ECG75 1/0 for warp yarn
ECG75 1/0 is used for the weft yarn, and the weaving density is 40 yarns / 25 mm for the warp yarn and 38 yarns / 25 mm for the weft yarn, and the fabric weight is 214 g / m ² using the air jet jet in the plain weave design. A glass cloth having an average thickness of 0.19 mm was woven. The space between the warp yarns and the yarn was 0 mm (adjacent yarns were overlapped with the weft yarns therebetween, or were in substantially the same position), and the space between the weft yarns was 0.08 mm.

(Example 2) ECG75 1/0 for warp yarn
ECG68 1/0 is used for the weft yarn, and the weaving density is 40 yarns / 25 mm for the warp yarn and 38 yarns / 25 mm for the weft yarn, and the fabric weight is 220 g / m ² using the air-jet rum in the plain weave design. A glass cloth having an average thickness of 0.19 mm was woven. The space between the warp yarn and the yarn was 0 mm, and the space between the weft yarn and the yarn was 0.05 mm.

(Example 3) ECG75 1/0 for warp yarn
ECG75 1/0 is used for the weft yarn, and the weaving density is 44 yarns / 25 mm for the warp yarn and 38 yarns / 25 mm for the weft yarn, and the fabric weight is 223 g / m ² using the air-jet looms in the plain weave design. A glass cloth having an average thickness of 0.20 mm was woven. The distance between the warp yarn and the yarn was 0 mm, and the distance between the weft yarn and the yarn was 0.08 mm.

(Comparative Example 1) ECG75 1/0 for warp yarn
ECG75 1/0 is used for the weft yarns, with a weaving density of 44 warp yarns / 25mm, 32.5 weft yarns / 25mm weft, and a plain weave fabric with an air jet jet fabric weight of 210g / A glass cloth having an average thickness of m ² and an average thickness of 0.19 mm was woven. The space between the vertical threads is 0 mm,
The space between the weft threads was 0.18 mm.

(Comparative Example 2) ECG75 1/0 for warp yarn
ECG75 1/0 is used for the weft yarn, and the weaving density is 40 yarns / 25 mm for the warp yarn and 36 yarns / 25 mm for the weft yarn, and the fabric weight is 210 g / m ² using the air-jet rum with the plain weave design. A glass cloth having an average thickness of 0.19 mm was woven. The space between the warp yarn and the yarn was 0 mm, and the space between the weft yarn and the yarn was 0.11 mm.

[0025]

[Table 1]

[0026]

[Table 2] From the results in Table 1, it was found that when the glass cloth of the present invention was used, the dimensional change behavior of the laminate was significantly improved.

[0027]

EFFECT OF THE INVENTION The laminated board for printed wiring boards using the glass cloth of the present invention has a small dimensional change and its variation at the time of manufacturing, and its anisotropy is smaller than that of the conventional one.
Even if the circuit pattern has a high density, the scale factor need not be corrected, and the component positioning mark can be used to position the component only with the reference hole.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining a distance x between a glass thread forming a glass cloth and a glass thread.

Claims (3)

[Claims] 1. A glass cloth woven from a warp yarn and a weft yarn, wherein a distance x between the glass yarn and the glass yarn constituting the glass cloth is 0.1 in both the warp direction and the weft direction.
A glass cloth characterized in that it is less than or equal to mm, and either or both of the glass warp warp yarn and the weft yarn are G75 1/0 or G68 1/0 designated by JIS R3413. (However, the distance between the yarns referred to here indicates the distance x shown in FIG. 1.) 2. The weaving shrinkage ratio of the glass yarn in the direction in which the number of the weaving glass yarns per unit length is large is larger than the weaving shrinkage ratio of the glass yarn in the direction in which the number of the weaving yarns is small. Glass cloth. 3. The glass cloth according to claim 1, wherein the ratio of the weaving shrinkage ratio of the warp yarns to the weaving shrinkage ratio of the weft yarns is 0.7 to 1.3.