TWI851261B - Glass fiber cloth, surface treated glass fiber cloth, prepreg and printed circuit board - Google Patents

Abstract

The present invention provides a glass fiber cloth having both good fiber opening degree and good fiber opening uniformity, and a surface treated glass fiber cloth, a prepreg, and a printed circuit board made using the glass fiber cloth. The glass fiber cloth is woven from a plurality of warp yarns and a plurality of weft yarns of glass fiber yarns. The average open modulus per unit area SD of the glass fiber cloth is 0.35 to 0.75, the average uniformity coefficient per unit area RA is 0.10 to 0.40, and the RA/SD value is 0.10 to 1.10. The definitions of the SD and the RA are as follows: W is the average width of the warp yarns, F is the average width of the weft yarns, _Dw is the average weaving density of the warp yarns, _Df is the average weaving density of the weft yarns, _Rw is the width full distance of the warp yarns, and _Rf is the width full distance of the weft yarns. SD = ; RA = .

Description

Glass fiber cloth, surface treated glass fiber cloth, prepreg and printed circuit board

The present invention relates to a fiber cloth, in particular to a glass fiber cloth and its application.

With the rapid development of technology, electronic products are being researched and developed with the goal of multifunctionality, fast transmission, lightness, and compactness, which has promoted the glass fiber cloth (hereinafter referred to as glass fiber cloth) used to manufacture printed circuit boards (PCBs) to move forward with the goal of making the thickness thinner. In order to make the thickness of the glass fiber cloth thinner, glass fiber yarns with a smaller average single filament diameter are used as warp yarns and weft yarns for weaving, but this will make the yarn window (i.e. the gap between the warp yarns and weft yarns in the glass fiber cloth) of the produced glass fiber cloth account for a higher area. When the area of the screen is too high, a fiber weave effect is likely to occur when the signal passes through a printed circuit board made of such glass fiber cloth, causing a negative impact on the transmission rate of the signal.

In order to solve the above problems, the commonly used solution strategy is to increase the fiber opening (also called fiber splitting) of the glass fiber cloth. The fiber opening refers to the technology of opening and evenly spreading the multiple single filaments constituting the glass fiber yarn to increase the surface area of the glass fiber yarn, thereby reducing the yarn window of the glass fiber cloth. For example, Patent Publication No. 720996 of the Republic of China and Patent Publication No. 723117 of the Republic of China both disclose a glass fiber cloth with a specific fiber opening degree.

However, the inventors have discovered that if the fiberglass cloth only meets the declared fiber opening degree but has poor fiber opening uniformity, that is, the size difference of each screen in the fiberglass cloth is too large, the prepreg made using the fiberglass cloth will have microvoids. In the process of manufacturing the printed circuit board, the prepreg will have excessive shrinkage and deformation, thereby causing the printed circuit board to bend and warp, thereby resulting in a poor yield of the printed circuit board.

Therefore, the first object of the present invention is to provide a glass fiber cloth having both good fiber opening degree and good fiber opening uniformity.

Therefore, the glass fiber cloth of the present invention is woven from a plurality of warp yarns and a plurality of weft yarns of glass fiber yarns, and the average fiber spreading modulus per unit area SD of the glass fiber cloth is between 0.35 and 0.75, the average uniformity modulus per unit area RA is between 0.10 and 0.40, and the RA/SD value is between 0.10 and 1.10, and the definitions of the SD and the RA are as follows: SD = and RA = ; wherein W is the average width of the warp yarns, F is the average width of the weft yarns, _Dw is the average weaving density of the warp yarns, _Df is the average weaving density of the weft yarns, _Rw is the width of the warp yarns and _Rf is the width of the weft yarns.

The second object of the present invention is to provide a surface treated glass fiber cloth.

Therefore, the surface treated glass fiber cloth of the present invention is made by surface treating the above-mentioned glass fiber cloth, wherein the surface treatment comprises reacting the glass fiber cloth with a treatment liquid to change the property of the glass fiber cloth, and the treatment liquid is made using a treatment agent selected from aminosilane coupling agent, alkenylsilane coupling agent, acryloxysilane coupling agent or any combination thereof.

The third object of the present invention is to provide a prepreg.

Therefore, the prepreg of the present invention is formed by partially curing an impregnated cloth comprising a resin and the above-mentioned surface-treated glass fiber cloth.

The fourth object of the present invention is to provide a printed circuit board.

Therefore, the printed circuit board of the present invention is made using the prepreg mentioned above.

The effect of the present invention is that the inventor comprehensively considers the average width, average weaving density and width of the warp yarns and the weft yarns to design the SD and the RA, and limits the SD to be between 0.35 and 0.75, the RA to be between 0.10 and 0.40, and the RA/SD value to be between 0.10 and 1.10, so that the glass fiber cloth of the present invention has both good fiber opening degree and good The fiber opening uniformity makes the surface-treated glass fiber cloth of the present invention made by using the glass fiber cloth also have the advantages of good fiber opening degree and good fiber opening uniformity, so that the prepreg of the present invention made by using the surface-treated glass fiber cloth has a good appearance and no glue holes, and then the printed circuit board of the present invention made by using the prepreg not only has a high yield but also has the advantage of fast signal transmission.

The present invention provides a glass fiber cloth, a surface-treated glass fiber cloth made using the glass fiber cloth, a prepreg made using the surface-treated glass fiber cloth, and a printed circuit board made using the prepreg. The present invention is described in detail below.

〈Fiberglass cloth〉

The glass fiber cloth of the present invention is woven from a plurality of warp yarns and a plurality of weft yarns of glass fiber yarns. The average fiber spreading modulus per unit area SD of the glass fiber cloth is between 0.35 and 0.75, the average uniformity modulus per unit area RA is between 0.10 and 0.40, and the RA/SD value is between 0.10 and 1.10.

The SD and the RA are defined as follows: SD = RA = ; W is the average width of the warp yarns; F is the average width of the weft yarns; _Dw is the average weaving density of the warp yarns; _Df is the average weaving density of the weft yarns; _Rw is the width full range of the warp yarns, that is, the difference between the maximum width and the minimum width of the warp yarns; and _Rf is the width full range of the weft yarns, that is, the difference between the maximum width and the minimum width of the weft yarns.

The average fiber opening coefficient per unit area SD represents the "fiber opening degree" of the glass fiber cloth. It represents the average overlapping area of the warp yarns and the weft yarns. 25400 is the unit of weaving density (root/25.4mm=root/25400μm), which represents the maximum width that each warp yarn and each weft yarn can be assigned, so It refers to the maximum area that each warp yarn and each weft yarn can be allocated to, which includes the area of each warp yarn overlapping with each weft yarn (see Area A of Figure 1), the area of each warp yarn not overlapping with each weft yarn (see Area B of Figure 1), the area of each weft yarn not overlapping with each warp yarn (see Area C of Figure 1), and the area of each screen window (see Area D of Figure 1).

The average unit area uniformity coefficient RA represents the "fiber opening uniformity" of the glass fiber cloth. represents the full width factor of the warp yarns (that is, the ratio of the full width of the warp yarns to the average width), represents the full-range coefficient of the equal-latitude yarn (i.e. the ratio of the full-range width of the equal-latitude yarn to the average width), so It refers to the geometric mean of the full-distance coefficients of the warp yarns and the weft yarns, which shows the distribution of the warp yarns and the weft yarns in the fiberglass cloth, that is, the size difference of the warp yarns and the weft yarns in the fiberglass cloth, which corresponds to the size difference of each screen window in the fiberglass cloth.

By controlling the SD and the RA and keeping the RA/SD value within the above range, the glass fiber cloth can have both good fiber opening degree and good fiber opening uniformity, that is, the screen area of the glass fiber cloth is low and the size difference of each screen in the glass fiber cloth is small, so that the surface-treated glass fiber cloth made using the glass fiber cloth also has the advantages of good fiber opening degree and good fiber opening uniformity, so that the prepreg made using the surface-treated glass fiber cloth has a good appearance and no glue holes, and then the printed circuit board made using the prepreg not only has a high yield but also has the advantage of fast signal transmission.

If the SD is less than 0.35, the fiber opening degree of the glass fiber cloth will be lower, that is, the window area of the glass fiber cloth will be higher, and the glass fiber effect will easily occur when the signal passes through the printed circuit board made of the glass fiber cloth, causing the transmission rate of the signal to be adversely affected. Generally, in order to increase the fiber opening degree of the glass fiber cloth, the water pressure used for fiber opening during the production of the glass fiber cloth will be increased accordingly. If the SD is greater than 0.75, it means that the fiber opening degree of the glass fiber cloth is relatively high. However, the multiple warp yarns and multiple weft yarns in the glass fiber cloth may break due to the excessively high water pressure during fiber opening, resulting in the fiber surface of the glass fiber cloth having hairiness defects, causing the prepreg made using the glass fiber cloth to have particle defects, and causing the printed circuit board made using the prepreg to have bump defects.

If the RA is greater than 0.40, the fiber opening uniformity of the glass fiber cloth will be poor, that is, the size difference of each screen in the glass fiber cloth will be large, resulting in the presence of glue holes in the prepreg made using the glass fiber cloth. In the process of manufacturing the printed circuit board, the prepreg will have excessive shrinkage and deformation, thereby causing the printed circuit board to bend and warp, thereby causing the yield of the printed circuit board to be poor.

If the RA/SD value is greater than 1.10, even if the SD is between 0.35 and 0.75 and the RA is between 0.10 and 0.40, the prepreg made using the glass fiber cloth will still have a poor appearance and glue holes, resulting in a poor yield of the printed circuit board made using the prepreg. In order to make the prepreg have a better appearance, preferably, the RA/SD value is between 0.20 and 1.00; more preferably, the RA/SD value is between 0.20 and 0.90.

In some embodiments of the present invention, each warp yarn and each weft yarn are respectively composed of a plurality of single filaments, the average single filament diameter in each warp yarn ranges from 3.0 μm to 5.0 μm and the average single filament number ranges from 30 to 200, and the average single filament diameter in each weft yarn ranges from 3.0 μm to 5.0 μm and the average single filament number ranges from 30 to 200. The single filaments are made by spinning glass raw materials, and the glass raw materials are, for example but not limited to, conventional electronic grade glass (such as E-glass) raw materials, low dielectric constant (low K) glass raw materials, low thermal expansion coefficient (low CTE) glass raw materials, or glass raw materials with both low dielectric constant and low thermal expansion coefficient.

In some embodiments of the present invention, the average thickness of the glass fiber cloth ranges from 10.0 μm to 50.0 μm; and the average basis weight of the glass fiber cloth ranges from 10.0 g/m ² to 50.0 g/m ² .

In some embodiments of the present invention, based on the average area of the glass fiber cloth, the average weaving density of the warp yarns ranges from 50 yarns/25.4 mm to 100 yarns/25.4 mm, and the average weaving density of the weft yarns ranges from 50 yarns/25.4 mm to 100 yarns/25.4 mm.

The glass fiber cloth is made from an unfibered glass fiber cloth through a process including a fiber opening treatment. As long as the glass fiber cloth has an SD value of 0.35 to 0.75, an RA value of 0.10 to 0.40, and an RA/SD value of 0.10 to 1.10, any known fiber opening treatment operation method and equipment are applicable to making the glass fiber cloth, without limiting the specific operation method and equipment of the fiber opening treatment. In some embodiments of the present invention, the fiber opening process is performed by spraying a high-pressure water column onto the unfibered glass fiber cloth with a fiber opening machine and applying a tension to the unfibered glass fiber cloth to open the fiber. The tension range is, for example but not limited to, 50N to 300N, and the water pressure range of the high-pressure water column is, for example but not limited to, 20kg to 80kg.

〈Surface treated fiberglass cloth〉

The surface treated fiberglass cloth of the present invention is made by surface treating the fiberglass cloth as described above, wherein the surface treatment comprises reacting the fiberglass cloth with a treatment liquid to change the properties of the fiberglass cloth so that the surface treated fiberglass cloth can react with resin in the back-end process. Since the fiberglass cloth has the advantages of good fiber opening degree and good fiber opening uniformity, the surface treated fiberglass cloth also has the advantages of good fiber opening degree and good fiber opening uniformity.

In some embodiments of the present invention, the treatment solution is prepared by using a treatment agent, which is selected from aminosilane coupling agents, alkenylsilane coupling agents, acryloxysilane coupling agents, or any combination thereof. The aminosilane coupling agent is, for example, but not limited to (3-aminopropyl)trimethoxysilane, etc. The alkenylsilane coupling agent is, for example, but not limited to vinyltrimethoxysilane, etc. The acryloxysilane coupling agent is, for example, but not limited to 3-(methacryloyloxy)propyltrimethoxysilane, etc. In some embodiments of the present invention, the aminosilane coupling agent is (3-aminopropyl)trimethoxysilane, the alkenylsilane coupling agent is vinyltrimethoxysilane, and the acryloxysilane coupling agent is 3-(methacryloxy)propyltrimethoxysilane.

〈Prepreg〉

The prepreg of the present invention is formed by partially curing an impregnated cloth comprising a resin and the surface-treated glass fiber cloth as described above. More specifically, the preparation of the prepreg includes impregnating the surface-treated glass fiber cloth serving as both a reinforcement and an insulation material into the resin to obtain the impregnated cloth, and then partially curing the impregnated cloth to become a partially hardened state (B-stage). Since the surface-treated glass fiber cloth has the advantages of good fiber opening degree and good fiber opening uniformity, that is, the screen area of the surface-treated glass fiber cloth is low and the size difference of each screen in the surface-treated glass fiber cloth is small, the area of the surface-treated glass fiber cloth that can be filled with the resin is relatively small, so that the prepreg made of the surface-treated glass fiber cloth has a good appearance and does not have glue holes.

The resin is, for example, but not limited to, a thermosetting resin or a UV curable resin. In some embodiments of the present invention, the resin is a thermosetting resin. The thermosetting resin is, for example, but not limited to, a polyphenylene ether resin, a phenolic resin, an epoxy resin, a urea-formaldehyde resin, an unsaturated polyester, a melamine resin, a fluororesin, or a bismaleimide triazine resin (BT resin, also known as bismaleimide triazine resin). The photocurable resin is, for example, but not limited to, a photosensitive polyurethane resin or a photosensitive acrylic resin. In some embodiments of the present invention, the thermosetting resin is selected from epoxy resin, polyphenylene ether resin or dimaleimide-triazine resin.

A back-end application of the prepreg includes stacking multiple layers of the prepreg and adding a copper foil layer on at least one side to obtain a laminate, and then hot pressing the laminate to obtain a copper clad laminate (CCL). In some embodiments of the present invention, the preparation of the prepreg also includes using an inorganic filler to prepare the impregnated cloth, so the prepreg formed by partially curing the impregnated cloth also includes an inorganic filler to adjust the properties of the copper foil laminate made using the prepreg, such as thermal conductivity, laser drilling properties, and thermal expansion properties, so that a printed circuit board made using the copper foil laminate has better reliability.

〈Printed Circuit Board〉

The printed circuit board of the present invention is made using the prepreg as described above. More specifically, the back-end application of the prepreg also includes drilling holes, gold plating and etching circuit patterns on the copper foil substrate to produce the printed circuit board. Therefore, since the prepreg has a good appearance and does not have glue holes, the printed circuit board produced using the prepreg will not have the problem of poor yield.

The present invention will be further described with respect to the following embodiments, but it should be understood that the embodiments are only for illustration and description and should not be construed as limitations on the implementation of the present invention.

〈Implementation Example 1 〉

Manufacturing of fiberglass cloth: Multiple fiberglass yarns as warp yarns are slurried and processed in sequence to obtain a weaving shaft. Then, the weaving shaft is placed in an air jet weaving machine (brand: Toyota, Japan; model: JAT710) and interwoven with multiple fiberglass yarns as weft yarns to form an un-fibered fiberglass. The unopened glass fiber cloth is subjected to a desizing treatment and a fiber opening treatment in sequence to obtain a glass fiber cloth, wherein the original yarn specifications of the warp yarns and the weft yarns (average single filament diameter and average single filament number), the tension applied to the unopened glass fiber cloth during the fiber opening treatment, and the water pressure of the high-pressure water column are shown in Table 1.

Preparation of surface treated glass fiber cloth: The glass fiber cloth is soaked in the treatment solution for 30 seconds and then dried at 150°C to obtain the surface treated glass fiber cloth. The treatment solution is prepared by hydrolyzing an aminosilane coupling agent and an acetic acid aqueous solution for 30 minutes under a pH range of 3.5 to 5.5. The amount of the aminosilane coupling agent is 0.08wt%, based on the total amount of the aminosilane coupling agent and the acetic acid aqueous solution being 100wt%.

The manufacturing method of the prepreg is as follows: the surface treated glass fiber cloth is impregnated in a resin solution to obtain an impregnated cloth, and then the impregnated cloth is cured at 210°C for 6 minutes to obtain a partially hardened prepreg. The resin solution is obtained by mixing a resin (specifically bismaleimide-triazine resin; brand is Suiye Industrial Co., Ltd.; model number is BT-0001) and a solvent (specifically butanone), and the content of the resin is 50wt% based on the total amount of the resin solution as 100wt%.

〈Implementation Example 2 to 13 and Comparison Examples 1 to 7 〉

The differences between Examples 2 to 13 and Comparative Examples 1 to 7 and Example 1 are shown in Tables 1 to 3. Glass fiber fabrics with different fiber opening degrees and different fiber opening uniformities are obtained by using warp yarns and weft yarns of different raw yarn specifications and different fiber opening treatment conditions. In the resin solutions used in Examples 2 to 13 and Comparative Examples 1 to 7, if the specific type of the resin is epoxy resin (brand name: Nan Ya Plastics Co., Ltd.; model number: NPEB475 K70), the corresponding solvent is propylene glycol methyl ether, and the content of the resin is 60wt% based on the total amount of the resin solution as 100wt%, and the impregnated cloth is cured at 190°C for 6 minutes; if the specific type of the resin is polyphenylene ether resin (brand name: SABIC; model number: NORYL SA9000), the corresponding solvent is butanone, and the content of the resin is 65wt% based on the total amount of the resin solution as 100wt%, and the impregnated cloth is cured at 180°C for 4 minutes.

〈Evaluation Items〉

The following uses Example 1 as an example to explain the specification measurement method of the glass fiber cloth in Examples 1 to 13 and Comparative Examples 1 to 7, as well as the specification measurement method and appearance evaluation method of the prepreg. The measurement results and appearance evaluation results are shown in Tables 1 to 3.

Measurement of the average weaving density of warp yarns ( _Dw ) and the average weaving density of weft yarns ( _Df ): The surface of the glass fiber fabric of Example 1 was measured using a fabric warp and weft density tester (brand: Textest Instruments; model: FX3250) to obtain the average weaving density of multiple warp yarns and the average weaving density of multiple weft yarns in the glass fiber fabric of Example 1.

Measurement of the average width of the warp yarn (W) and the average width of the weft yarn (F): A glass fiber cloth of Example 1 with a length of 30 cm was taken and divided into five measurement areas along the width direction. The glass fiber cloth was placed under a microscope (brand: NIKON; model: ME600; magnification: 5x) to take pictures of the measurement areas respectively to obtain 5 pictures. Then, the image length measurement software (named TS-Link) is used to measure the width of each warp yarn and each weft yarn in the photos respectively. Finally, the measured width data of the measurement areas (i.e., a total of 5 width data) are averaged to obtain the average width of multiple warp yarns and the average width of multiple weft yarns in the glass fiber cloth of Example 1.

The calculation method of the full width of the warp yarn (Rw) and the full width of the weft yarn ( _Rf ) is: _Rw = the difference between the maximum width and the minimum width among multiple warp yarns; _Rf = the difference between the maximum width and the minimum width among multiple weft yarns.

Measurement of average thickness of glass fiber cloth: The glass fiber cloth of Example 1 having a length of 30 cm and divided into five measuring areas is placed in an electronic micrometer caliper (brand: TESA MICROMASTER IP54; minimum measurement accuracy: 0.001 mm) to measure the thickness of the measuring areas respectively. Finally, the thickness data of the measuring areas measured (i.e., a total of 5 thickness data) are averaged to obtain the average thickness of the glass fiber cloth of Example 1.

Measurement of average basis weight of glass fiber cloth: The glass fiber cloth of Example 1 was cut into three equal parts, and each equal part was cut into samples of 30 cm×30 cm in size. Then, the samples were placed in an electronic balance (brand: OHAUS PR224; minimum measurement accuracy: 0.0001 g) for weight measurement, and the basis weights of the samples were calculated using the following formula. Finally, the basis weights of the samples (i.e., a total of 3 basis weight data) were averaged to obtain the average basis weight of the glass fiber cloth of Example 1. The formula is: basis weight of sample = weight of sample/area of sample.

Measurement of resin content in prepreg: According to the standard test method of IPC-TM-650 2.3.16.1 (1994 edition) "Resin Content of Prepreg Material (Treated Weight)", the glass fiber cloth of Example 1 and the prepreg of Example 1 were cut into samples with a size of 20 cm × 20 cm, and then the samples were placed in the electronic balance for weight measurement, and the resin content in the prepreg of Example 1 was calculated using the following formula. The formula is: Resin content in prepreg = (1-sample weight of glass fiber cloth/sample weight of prepreg) × 100%.

Measurement of average thickness of prepreg: A prepreg of Example 1 with a length of 30 cm was taken, and the prepreg was evenly divided into five measuring areas along the width direction. The prepreg was placed in the electronic micrometer to measure the thickness of the measuring areas respectively. Finally, the thickness data of the measuring areas measured (i.e., a total of 5 thickness data) were averaged to obtain the average thickness of the prepreg of Example 1.

Measurement of the number of glue holes in the prepreg and evaluation of the appearance of the prepreg: The prepreg of Example 1 was cut into samples of 5 cm × 5 cm in size, and then the sample was placed under the microscope for observation. If pinhole-sized holes were seen on the surface of the sample, they were glue holes, and the number of pinhole-shaped glue holes on the surface of the sample was calculated. When the number of glue holes in the prepreg was 0, the appearance of the prepreg was evaluated as good; when the number of glue holes in the prepreg was 1 to 100, the appearance of the prepreg was evaluated as having some pinholes; when the number of glue holes in the prepreg was more than 101, the appearance of the prepreg was evaluated as having obvious pinholes.

Table 1 Embodiment 1 2 3 4 5 6 7 Warp Average single filament diameter (μm) 4.0 4.0 4.0 4.0 4.0 4.0 4.5 Average number of single filaments (filaments) 40 40 50 50 100 100 100 Weaving Average single filament diameter (μm) 4.0 4.0 4.0 4.0 4.0 4.0 4.5 Average number of single filaments (filaments) 40 40 50 50 100 100 100 Fiber opening treatment Tension(N) 50 50 100 50 100 150 100 Water pressure(kg) 20 30 30 30 50 60 50 Glass fiber cloth Warp D _w (root/25.4mm) 95 95 95 95 75 75 70 W (μm) 139 141 135 154 203 187 210 R _w (μm) 27 59 45 31 62 92 37 Weaving D _f (root/25.4mm) 95 95 95 95 75 75 73 F (μm) 193 191 202 223 303 318 333 _Rf (μm) 32 27 35 28 30 99 42 SD 0.38 0.38 0.38 0.48 0.54 0.52 0.55 RA 0.18 0.24 0.24 0.16 0.17 0.39 0.15 RA/SD value 0.48 0.65 0.63 0.33 0.32 0.75 0.27 Average thickness (μm) 12.0 12.0 14.0 14.0 18.0 18.0 22.0 Average basis weight (g/m ² ) 10.1 10.1 12.3 12.3 19.5 19.5 23.0 Surface treated glass fiber cloth Type of treatment agent Aminosilane coupling agent Aminosilane coupling agent Aminosilane coupling agent Aminosilane coupling agent Vinyl Silane Coupling Agent Vinyl Silane Coupling Agent Aminosilane coupling agent Prepreg Resin type BT resin BT resin Epoxy Epoxy Polyphenylene ether resin Polyphenylene ether resin Epoxy Resin content (%) 80.7 81.1 76.7 76.0 73.7 74.2 71.5 Average thickness (μm) 15.3 14.8 18.2 18.1 23.9 24.2 26.5 Number of glue holes 0 0 0 0 0 0 0 Appearance good good good good good good good Note: a. The specific type of aminosilane coupling agent is (3-aminopropyl)trimethoxysilane. b. The specific type of vinylsilane coupling agent is vinyltrimethoxysilane. c. BT resin is the abbreviation of bismaleimide-triazine benzene resin.

Table 2 Embodiment 8 9 10 11 12 13 Warp Average single filament diameter (μm) 4.5 5.0 5.0 5.0 5.0 5.0 Average number of single filaments (filaments) 100 100 100 100 200 200 Weaving Average single filament diameter (μm) 4.5 5.0 5.0 5.0 5.0 5.0 Average number of single filaments (filaments) 100 100 100 100 200 200 Fiber opening treatment Tension(N) 150 250 250 200 250 300 Water pressure(kg) 50 40 50 40 60 80 Glass fiber cloth Warp D _w (root/25.4mm) 70 66 66 56 60 54 W (μm) 203 180 193 196 345 282 R _w (μm) 97 44 72 82 72 128 Weaving D _f (root/25.4mm) 73 68 68 56 47 54 F (μm) 301 347 337 398 487 433 _Rf (μm) 97 40 49 62 92 104 SD 0.48 0.43 0.45 0.38 0.73 0.55 RA 0.39 0.17 0.23 0.26 0.20 0.33 RA/SD value 0.81 0.39 0.51 0.67 0.27 0.60 Average thickness (μm) 22.0 28.0 28.0 25.0 40.0 43.0 Average basis weight (g/m ² ) 23.0 29.5 29.5 24.0 47.0 43.5 Surface treated glass fiber cloth Type of treatment agent Aminosilane coupling agent Acryloyl Silane Coupling Agent Acryloyl Silane Coupling Agent Aminosilane coupling agent Aminosilane coupling agent Aminosilane coupling agent Prepreg Resin type Epoxy Polyphenylene ether resin Polyphenylene ether resin Epoxy Epoxy Epoxy Resin content (%) 71.8 68.6 68.9 68.3 63.8 65.9 Average thickness (μm) 26.7 33.8 34.0 30.6 50.8 51.3 Number of glue holes 0 0 0 0 0 0 Appearance good good good good good good Note: a. The specific type of aminosilane coupling agent is (3-aminopropyl)trimethoxysilane. b. The specific type of acryloxysilane coupling agent is 3-(methacryloyloxy)propyltrimethoxysilane.

Table 3 Comparison Example 1 2 3 4 5 6 7 Warp Average single filament diameter (μm) 4.0 4.0 4.0 4.0 4.5 5.0 5.0 Average number of single filaments (filaments) 40 40 50 100 100 100 100 Weaving Average single filament diameter (μm) 4.0 4.0 4.0 4.0 4.5 5.0 5.0 Average number of single filaments (filaments) 40 40 50 100 100 100 100 Fiber opening treatment Tension(N) 150 100 100 100 200 250 250 Water pressure(kg) 40 30 50 60 50 60 50 Glass fiber cloth Warp D _w (root/25.4mm) 95 95 95 75 70 66 56 W (μm) 107 122 137 199 187 161 184 R _w (μm) 79 54 65 129 144 97 97 Weaving D _f (root/25.4mm) 95 95 95 75 73 68 56 F (μm) 150 175 182 270 309 311 338 _Rf (μm) 54 61 61 141 114 77 119 SD 0.22 0.30 0.35 0.47 0.46 0.35 0.30 RA 0.52 0.39 0.40 0.58 0.53 0.39 0.43 RA/SD value 2.30 1.32 1.14 1.24 1.16 1.11 1.43 Average thickness (μm) 12.0 12.0 14.0 18.0 22.0 28.0 25.0 Average basis weight (g/m ² ) 10.0 10.0 12.3 19.5 23.0 29.5 24.0 Surface treated glass fiber cloth Type of treatment agent Aminosilane coupling agent Aminosilane coupling agent Aminosilane coupling agent Vinyl Silane Coupling Agent Aminosilane coupling agent Acryloyl Silane Coupling Agent Aminosilane coupling agent Prepreg Resin type BT resin BT resin Epoxy Polyphenylene ether resin Epoxy Polyphenylene ether resin Epoxy Resin content (%) 80.5 81.0 76.5 74.5 72.1 68.5 68.6 Average thickness (μm) 14.9 15.1 18.5 24.3 26.8 33.7 30.9 Number of glue holes 361 244 48 198 71 35 213 Appearance Obvious pinhole Obvious pinhole Some pinholes Obvious pinhole Some pinholes Some pinholes Obvious pinhole Note: a. The specific type of aminosilane coupling agent is (3-aminopropyl)trimethoxysilane. b. The specific type of alkenylsilane coupling agent is vinyltrimethoxysilane. c. The specific type of acryloxysilane coupling agent is 3-(methacryloyloxy)propyltrimethoxysilane. d. BT resin is the abbreviation of bismaleimide-triazine resin.

As can be seen from Tables 1 to 3, the glass fiber cloths of Examples 1 to 13 fully meet the requirements of SD between 0.35 and 0.75, RA between 0.10 and 0.40, and RA/SD value between 0.10 and 1.10, and there are no glue holes on the surface of the prepreg, so the appearance is good. On the other hand, the glass fiber cloths of Comparative Examples 1 to 7 do not fully meet the requirements of SD between 0.35 and 0.75, RA between 0.10 and 0.40, and RA/SD value between 0.10 and 1.10, and there are glue holes on the surface of the prepreg. By comparison, it is proved that Examples 1 to 13 indeed successfully make the surface of the prepreg free of any glue holes by making the glass fiber cloth fully meet the requirements of SD being between 0.35 and 0.75, RA being between 0.10 and 0.40, and RA/SD value being between 0.10 and 1.10.

In summary, the glass fiber cloth of the present invention has the SD between 0.35 and 0.75, the RA between 0.10 and 0.40, and the RA/SD value between 0.10 and 1.10, and thus successfully has both good fiber opening degree and good fiber opening uniformity. As a result, the surface-treated glass fiber cloth of the present invention made using the glass fiber cloth also has good fiber opening degree and good fiber opening uniformity, so that the prepreg of the present invention made using the surface-treated glass fiber cloth has a good appearance and no glue holes. Then, the printed circuit board of the present invention made using the prepreg not only has a high yield but also has the advantage of fast signal transmission, so the purpose of the present invention can be achieved.

However, the above is only an example of the present invention and should not be used to limit the scope of the present invention. All simple equivalent changes and modifications made according to the scope of the patent application and the content of the patent specification of the present invention are still within the scope of the present patent.

A: The overlapping area of each warp yarn and each weft yarn

B: The area of each warp yarn that does not overlap with each weft yarn

C: The area of each weft yarn that does not overlap with each warp yarn

D: Area of each screen

Other features and effects of the present invention will be clearly presented in the implementation method with reference to the drawings, wherein: FIG. 1 is a partial schematic diagram of the glass fiber cloth of the present invention, wherein A represents the area of each warp yarn overlapping with each weft yarn, B represents the area of each warp yarn not overlapping with each weft yarn, C represents the area of each weft yarn not overlapping with each warp yarn, and D represents the area of each screen window.

A: The overlapping area of each warp yarn and each weft yarn

B: The area of each warp yarn that does not overlap with each weft yarn

C: The area of each weft yarn that does not overlap with each warp yarn

D: Area of each screen window

Claims (10)

A glass fiber cloth is woven from a plurality of warp yarns and a plurality of weft yarns of glass fiber yarns, wherein the average fiber spreading modulus per unit area SD of the glass fiber cloth is between 0.35 and 0.75, the average uniformity modulus per unit area RA is between 0.10 and 0.40, and the RA/SD value is between 0.10 and 1.10, wherein the definitions of the SD and the RA are as follows:

Wherein, W is the average width of the warp yarns, F is the average width of the weft yarns, _Dw is the average weaving density of the warp yarns, _Df is the average weaving density of the weft yarns, _Rw is the width of the warp yarns, and _Rf is the width of the weft yarns. The glass fiber cloth as described in claim 1, wherein the RA/SD value is between 0.20 and 1.00. The glass fiber cloth as described in claim 2, wherein the RA/SD value is between 0.20 and 0.90. The glass fiber cloth as described in claim 1, wherein each warp yarn and each weft yarn are each composed of a plurality of single filaments, the average single filament diameter in each warp yarn ranges from 3.0 μm to 5.0 μm and the average number of single filaments ranges from 30 to 200, and the average single filament diameter in each weft yarn ranges from 3.0 μm to 5.0 μm and the average number of single filaments ranges from 30 to 200. The glass fiber cloth as claimed in claim 1, wherein the average thickness of the glass fiber cloth ranges from 10.0 μm to 50.0 μm; the average basis weight of the glass fiber cloth, calculated based on the average area of the glass fiber cloth, ranges from 10.0 g/m ² to 50.0 g/m ² ; the average weaving density of the warp yarns ranges from 50 yarns/25.4 mm to 100 yarns/25.4 mm, and the average weaving density of the weft yarns ranges from 50 yarns/25.4 mm to 100 yarns/25.4 mm. A surface treated glass fiber cloth is obtained by surface treating the glass fiber cloth as described in any one of claims 1 to 5, wherein the surface treatment comprises reacting the glass fiber cloth with a treatment liquid to change the properties of the glass fiber cloth, wherein the treatment liquid is prepared using a treatment agent selected from aminosilane coupling agents, alkenylsilane coupling agents, acryloxysilane coupling agents or any combination thereof. A prepreg formed by partially curing an impregnated cloth comprising a resin and a surface-treated glass fiber cloth as described in claim 6. The prepreg as described in claim 7, wherein the resin is a thermosetting resin. The prepreg as described in claim 8, wherein the thermosetting resin is selected from epoxy resin, polyphenylene ether resin or dimaleimide-triazine resin. A printed circuit board is made using a prepreg as described in any one of claims 7 to 9.

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