Glass cloth, prepreg, printed circuit boards, integrated circuits, and electronic devices

Abstract

The present invention provides a glass cloth that can achieve excellent dimensional stability in prepregs and printed wiring boards, and can suppress pinholes in the prepreg. The glass cloth of the present invention comprises glass yarn as warp and weft yarn, and the weaving density of the warp and weft yarn is 50 to 110 yarns / 25 mm, the thickness of the glass cloth is less than 20 μm, and the average gap spacing in the weft direction and the warp direction of forming cage-like holes is 162 to 240 μm and 65 to 200 μm, respectively.

Description

Technical Field

[0001] This invention relates to a glass cloth, a prepreg, and a printed wiring board, etc. Prior Technology

[0002] In recent years, with the miniaturization of electronic devices, there has been a strong demand for lightweight printed circuit boards (PCBs). In order to achieve low-weight materials used in PCBs, low-weight glass cloth contained in the prepreg is also required.

[0003] Patent documents 1-4 report a method for producing a prepreg using low-quality glass cloth. All of patent documents 1-4 attempt to suppress pinholes in the prepreg by controlling the openness of the glass cloth or the gap between the yarn widths. Furthermore, Patent Document 5 reports a method for manufacturing printed wiring boards using low-quality glass cloth. Also, Patent Document 6 reports a method for manufacturing printed wiring boards using low-quality glass cloth, and attempts to improve the dimensional stability and mechanical properties of the printed wiring board by controlling the value of the "surface glass cloth coverage rate". [Previous Technical Documents] [Patent Literature]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2021-075805 [Patent Document 2] Japanese Patent Application Publication No. 2017-043873 [Patent Document 3] Japanese Patent Application Publication No. 2018-021274 [Patent Document 4] WO2019 / 163159 Publication No. [Patent Document 5] WO2015 / 033731 Publication No. [Patent Document 6] Japanese Patent Application Publication No. 2005-213656 Summary of the Invention

[0005] [The problem the invention aims to solve] In recent years, with the increasing demands for high functionality and miniaturization of digital machines, there has been a growing demand for printed circuit boards (PCBs) to be even smaller, thinner, and with finer and higher-density wiring. Therefore, for glass cloth and prepregs used in applications such as PCBs, thinner fabrics and prepregs are required not only to be thinner but also to have greater dimensional stability.

[0006] Generally speaking, using glass yarn with a lower TEX value (mass per 1000 m of glass yarn) and weaving it with a high density is beneficial for the thin film formation of glass cloth and prepreg.

[0007] Here, in glass cloth, the gaps between the warp and weft yarns are called "basket holes." Because these basket holes are not fully filled by the thermosetting resin, defects called "pinholes" may occur in the prepreg. It is known that by controlling the weave density to a high density, the following advantages can be obtained: it is easier to suppress the formation of defects (pinholes) in the prepreg, and the glass cloth is less prone to wrinkling during transport.

[0008] However, the inventors discovered that if the weave density is controlled to be high, the amount of thermosetting resin on the front and back sides of the prepreg is likely to differ, which in turn leads to a decrease in the dimensional stability of the prepreg and the obtained printed wiring board.

[0009] Therefore, the purpose of this invention is to provide a glass cloth that can achieve excellent dimensional stability in prepregs and printed wiring boards, and can suppress pinholes in the prepreg. Furthermore, the present invention aims to provide a prepreg obtained using the glass cloth, and a printed wiring board, etc. [Technical means to solve the problem]

[0010] One aspect of the present invention is described below. [1] A type of glass cloth, comprising glass yarn as warp and weft yarn, and The weave density of the aforementioned warp and weft yarns is 50-110 yarns / 25 mm. The thickness of the aforementioned glass cloth is less than 20 μm. The average gaps in the weft and warp directions forming the cage-like holes are 162~240 μm and 65~200 μm, respectively. [2] The glass cloth described in Project 1 has a TEX value of 0.2~2.0 g / 1000 m. [3] The glass cloth described in Project 1 or 2 has an average area of ​​15,000 to 45,000 μm². [4] The glass cloth described in any of items 1 to 3 contains the aforementioned cage-like pores with an area of ​​15,000 to 45,000 μm². [5] As described in any of items 1 to 4, the glass cloth contains a plurality of glass filaments. The diameter of the glass filaments in the aforementioned glass yarn is 2.0~4.5 μm. The number of glass filaments mentioned above is 10 to 50. [6] For example, the glass cloth described in any of items 1 to 5, wherein the ratio (short side / long side) of the cage-shaped holes is 0.4 to 0.8. [7] The glass cloth described in any of items 1 to 6 has an average open fiber ratio of 70 to 110% for the warp yarns and / or an average open fiber ratio of 90 to 140% for the weft yarns. [8] For example, in any of the glass cloths described in items 1 to 7, the ratio of the aforementioned glass yarns (warp yarn density / weft yarn density) does not reach 1.0. [9] The glass cloth described in any of items 1 to 8, wherein the glass yarn is surface-treated with a silane coupling agent.

[10] The glass cloth described in Project 9 contains a silane coupling agent comprising the silane coupling agent represented by the following general formula (1): X(R) 3-nSiY n···(1) (In the formula, X is an organic functional group having one or more amine groups.) Organic functional groups having one or more unsaturated double bonds with free radical reactivity, or Organic functional groups possessing one or more amine groups and one or more unsaturated double bonds with free radical reactivity. Y is an alkoxy group, n is an integer from 1 to 3, and R is an alkoxy group selected from the group consisting of methyl, ethyl, and phenyl groups.

[11] A prepreg comprising a glass cloth as described in any one of items 1 to 10, and a thermosetting resin.

[12] A printed wiring board comprising a prepreg as described in item 11.

[13] An integrated circuit comprising a printed wiring board as described in Item 12.

[14] An electronic device comprising a printed wiring board as described in item 12. [Effects of the Invention]

[0011] The present invention can provide the following, etc. According to the present invention, a glass cloth can be provided that can achieve excellent dimensional stability in prepregs and printed wiring boards, and can suppress pinholes in the prepreg. Furthermore, according to the present invention, a prepreg, printed wiring board, integrated circuit, and electronic device obtained using the glass cloth can be provided. Implementation

[0012] Hereinafter, embodiments of the present invention (hereinafter referred to as "this embodiment") will be described. However, the present invention is not limited to this embodiment, and therefore various changes can be made to the present invention without departing from its spirit.

[0013] In this specification, when multiple structures represented by the same symbol exist in the same formula, unless otherwise specified, each structure can be selected independently, and these structures can be the same or different from each other. Similarly, when multiple structures represented by the same symbol exist in different formulas, unless otherwise specified, each structure can also be selected independently, and these structures can be the same or different from each other. In this specification, the upper or lower limit values ​​within the numerical range described in stages can be replaced with corresponding upper or lower limit values ​​within the numerical range described in other stages, and further, can be replaced with the corresponding values ​​described in the embodiments.

[0014] Furthermore, in this specification, the term "step" is included not only when it is an independent step, but also when it cannot be clearly distinguished from other steps, as long as the function of the step can be achieved. In the contents shown in the figures, for the purpose of further clarity, there are instances where the scale, shape, and length are exaggerated.

[0015] [First Implementation] The glass cloth in this embodiment includes glass yarn as both warp and weft yarns, and The warp and weft yarn density is 50-110 yarns / 25 mm. The thickness of the glass cloth is less than 20 μm. The average gaps in the weft and warp directions forming the cage-like holes are 162~240 μm and 65~200 μm, respectively.

[0016] In terms of easily suppressing defects (pinholes) in the prepreg, it is advantageous to control the weave density of the glass cloth to be high. However, on the other hand, the inventors have discovered a disadvantage in the following aspect: the amount of thermosetting resin on the front and back sides of the prepreg is prone to differ. In this regard, the inventors have also discovered that if the weave density of the glass cloth is controlled to be high, not only is the amount of thermosetting resin on the front and back sides of the prepreg prone to differ, but the number of interlacing points is also prone to increase. In this case, the residual deformation margin for allowing the glass cloth to stretch in the warp and weft directions becomes larger, which in turn has an adverse effect on the dimensional stability of the prepreg and the printed wiring board. Based on the above-described considerations of the inventors, this embodiment allows for the effective suppression of pinholes in the prepreg and improvement of dimensional stability by appropriately adjusting the weave density of the glass yarn in the glass cloth and appropriately opening the warp yarns. The glass cloth according to this embodiment can also meet the expectations for thin-film production.

[0017] [Glass cloth] The glass cloth of this embodiment includes glass yarn as warp and weft yarns, and in one sample, the glass cloth of this embodiment is woven from glass yarn containing a plurality of glass filaments as warp and weft yarns. Preferably, the glass cloth has been surface-treated with the following surface treatment agent.

[0018] [Types of Glass] The glass type used in glass cloth, especially in glass cloth used for printed circuit boards, is preferably E-glass (alkali-free glass). Other suitable types include L-glass, NE-glass, D-glass, L2-glass, S-glass, T-glass, silica glass, and quartz glass. From the viewpoint of easily achieving excellent dielectric properties, L-glass, L2-glass, silica glass, and quartz glass are preferred, with silica glass and quartz glass being more preferred. Furthermore, from the viewpoint of easily improving the dimensional stability of laminates containing glass cloth, S-glass, T-glass, silica glass, and quartz glass are preferred, with silica glass and quartz glass being more preferred.

[0019] The elemental content in glass can be determined using methods such as atomic absorption spectrophotometry and inductively coupled plasma (ICP) emission spectrometry. For example, a calibration curve can be prepared in advance using a sample with a known concentration, such as ICP-AES or ICP-MS, and the elemental content in each glass can be determined based on the calibration curve.

[0020] [Dielectric constant and dielectric loss factor of glass at 10 GHz] The glass used in the glass cloth of this embodiment preferably has a dielectric constant of 7.0 F / m or less at 10 GHz, more preferably 6.0 or less, further preferably 5.0 or less, further preferably 4.5 or less, and especially preferably 4.0 or less. Furthermore, the glass used in the glass cloth of this embodiment preferably has a dielectric loss factor of 0.0070 or less at 10 GHz, more preferably 0.0065 or less, further preferably 0.0045 or less, further preferably 0.0030 or less, and especially preferably 0.0020 or less. By ensuring that the dielectric constant and / or dielectric loss factor of the glass are within the above ranges, the transmission loss of the printed circuit board can be easily reduced.

[0021] [Coefficient of thermal expansion (CTE) of glass] The CTE of the glass used in the glass cloth of this embodiment is preferably 6.0 ppm / ℃ or less, more preferably 5.0 ppm / ℃ or less, further preferably 3.5 ppm / ℃ or less, further preferably 3.0 ppm / ℃ or less, and particularly preferably 2.0 ppm / ℃ or less. By keeping the CTE of the glass within the above range, the dimensional stability of the prepreg and the printed wiring board can be easily improved.

[0022] [TEX value of glass yarn] The TEX value (mass of glass yarn per 1000 m) of the glass cloth used in this embodiment is preferably 0.2~2.0 g / 1000 m. More preferably 0.3~1.8 g / 1000 m, further preferably 0.4~1.6 g / 1000 m, further preferably 0.5~1.4 g / 1000 m, and particularly preferably 0.6~1.2 g / 1000 m. By keeping the TEX value of the glass yarn within the above range, it is easy to thin the glass cloth, prepreg, and printed wiring board.

[0023] [The physical properties and composition of glass cloth] According to JIS R3420, the mass of the glass cloth in this embodiment, measured by mass per unit area, can be 15.0 g / m² or less. From the viewpoint of thinning the prepreg or printed wiring board including the glass cloth, the mass of the glass cloth is preferably 12.0 g / m² or less, more preferably 11.0 g / m² or less, further preferably 10.0 g / m² or less, and particularly preferably 9.0 g / m² or less. Furthermore, the lower limit of the mass per unit area of ​​the glass cloth can, for example, exceed 0 g / m² or be 0.1 g / m² or more.

[0024] When controlling the quality of glass cloth to below 15.0 g / m², it is preferable to use finer glass yarn as the warp and weft yarns of the glass cloth. The diameter of the glass filaments in the glass yarn (filament diameter) is preferably 2.0~4.5 μm, more preferably 2.5~4.0 μm, further preferably 3.0~3.9 μm, and particularly preferably 3.2~3.8 μm. If the filament diameter is 2.0 μm or more, it is easier to ensure the breaking strength of the filaments, thus easily suppressing the formation of fine fibers. Furthermore, if the filament diameter is below 4.5 μm, it is difficult to control the quality of the glass cloth to below 15.0 g / m².

[0025] In this embodiment of the glass cloth, it is preferable that the warp yarn openness is 70-110% and / or the weft yarn openness is 90-140%. More preferably, the warp yarn openness is 75-108% and / or the weft yarn openness is 92-138%. Further preferably, the warp yarn openness is 80-106% and / or the weft yarn openness is 94-135%. Even more preferably, the warp yarn openness is 82-104% and / or the weft yarn openness is 95-130%. Particularly preferably, the warp yarn openness is 85-103% and / or the weft yarn openness is 96-128%. By controlling the warp and / or weft yarn openness of the glass cloth within the above ranges, wrinkles during glass cloth handling and pinholes in the prepreg can be easily suppressed. By keeping the openness below the upper limit of the aforementioned range, it is easy to prevent the openness from becoming too high, thus easily suppressing wrinkles during the handling of the glass cloth. On the other hand, by keeping the openness above the lower limit of the aforementioned numerical range, it is easy to reduce the pinhole rate during the production of the prepreg. The openness of the warp yarns can be adjusted through the openness step of the glass cloth, and can also be adjusted by the following operation: during warping, pressure (clamping) is applied to the warp yarns with a specified load using clamping rollers, and then the warp yarns are flattened. From the viewpoint that it is only easy to adjust the yarn width of the warp yarns, the openness of the warp yarns is preferably adjusted by flattening during warping. In this case, it is also easy to obtain the advantage of easily adjusting the openness of both the warp and weft yarns to the aforementioned range. The openness of the weft yarns can be adjusted through the openness step of the glass cloth. For example, by adjusting the pressure during high-pressure openness using a sprayer, the openness of the weft yarns can be easily adjusted to the aforementioned range.

[0026] The average open fiber density of the glass cloth in this embodiment is preferably 80-150%, more preferably 82%-140%, further preferably 84-135%, further preferably 85-130%, and most preferably 86-128%. By keeping the average open fiber density of the glass cloth within the above range, wrinkles during glass cloth handling and pinholes in the prepreg are easily and effectively suppressed. Furthermore, the average open fiber density of the glass cloth is expressed as the average of the open fiber density of the warp yarns and the open fiber density of the weft yarns.

[0027] In this embodiment, the number of glass filaments used in the warp and weft yarns of the glass cloth is preferably 10 to 50, more preferably 15 to 45, further preferably 20 to 43, and most preferably 25 to 40. If the number of filaments is 50 or less, it is easier to prevent insufficient widening when the glass cloth undergoes flattening processes such as fiber opening. Furthermore, if the number of filaments is 10 or more, it is easier to suppress the formation of fine fibers in the glass cloth. Glass filaments within the above-mentioned number range can be bundled during the formation of the glass yarn.

[0028] In this embodiment, the warp and weft yarn density of the glass cloth is in the range of 50 to 110 yarns / 25 mm. From the viewpoint that the effects of the present invention can be readily and significantly demonstrated, the warp and weft yarn density of the glass cloth in this embodiment is preferably 55 to 100 yarns / 25 mm, more preferably 60 to 98 yarns / 25 mm, further preferably 65 to 96 yarns / 25 mm, and most preferably 70 to 95 yarns / 25 mm. The weave density of the warp and weft yarns can also be different from each other. The weave density of the warp yarns can be greater than that of the weft yarns, and the weave density of the warp yarns can also be less than that of the weft yarns. Regarding the warp and / or weft yarns, if the weave density is less than 50 threads / 25 mm, not only are pinholes easily formed in the prepreg, but the rigidity of the glass cloth used as the core material of the resin substrate also becomes insufficient. As a result, it adversely affects the stability of dimensional changes. On the other hand, regarding the warp and / or weft yarns, if the weave density is greater than 110 threads / 25 mm, it is difficult to adjust the average gap interval in the weft direction and / or warp direction to within the range of this embodiment. In this case, it is difficult to improve the dimensional stability of the resin substrate.

[0029] The overlapping point of the warp and weft yarns of the glass cloth, i.e., the interlacing point, is the part that restrains the glass yarn. There is a small amount of residual deformation leeway at this interlacing point. Here, the inventors have discovered that when manufacturing the glass cloth, especially when tension is applied to the glass cloth, the residual deformation leeway near the interlacing point causes the glass cloth to elongate in the direction of the applied tension. Therefore, the inventors have discovered that reducing the number of interlacing points in the glass cloth is effective in improving the dimensional stability of the glass cloth, the prepreg, and the printed wiring board. By keeping the warp and weft yarn densities of the glass cloth within the aforementioned range, pinholes are prevented from forming in the prepreg. If the densities are within the aforementioned upper limit, excellent dimensional stability can be easily achieved.

[0030] In this embodiment, the ratio (warp density / weft density) in the glass cloth is preferably less than 1.0. More preferably, it is 0.9 or less, and even more preferably, it is 0.8 or less. Accordingly, it is easy to simultaneously suppress pinholes in the prepreg and improve the dimensional stability of the substrate.

[0031] In this embodiment, the thickness of the glass cloth is 20 μm or less. More preferably, the thickness of the glass cloth is 18 μm or less, further preferably 16 μm or less, even more preferably 13 μm or less, and most preferably 10 μm or less. By adjusting the thickness of the glass cloth to 20 μm or less, the expectation of thin-film fabrication for glass cloth, prepreg, and printed circuit boards can be adequately met. Furthermore, the thickness of the glass cloth can be 3 μm or more.

[0032] In this embodiment, "cage-like holes" refers to the gaps between the warp and weft yarns in the glass cloth. Furthermore, in this embodiment, "pinholes" refers to voids or defects in the prepreg. These spatial defects may occur, for example, due to the thermosetting resin not completely filling the cage-like holes. Generally speaking, if the average area of ​​the cage-like pores is made smaller, pinholes are less likely to occur, but the varnish is difficult to flow through the cage-like pores from the front to the back of the glass cloth (or from the back to the front). In this case, the resin layers on both sides of the obtained prepreg are prone to thickness differences, thus reducing dimensional stability. In this embodiment, in order to prevent pinholes from forming in the prepreg and to improve the dimensional stability of the substrate, the following fiber-opening method is performed on the average gap spacing in the weft direction (also known as the gap spacing between adjacent warp yarns) and the average gap spacing in the warp direction (also known as the gap spacing between adjacent weft yarns), thereby adjusting them to within a specified range.

[0033] The average gap spacing in the weft direction is 162~240 μm. More preferably, it is 165~235 μm, further preferably 170~230 μm, further preferably 172~225 μm, and most preferably 174~220 μm. If the average gap spacing in the weft direction is higher than the above range, the fiber opening of the glass cloth is prone to be insufficient, and therefore the prepreg is prone to pinholes. If the average gap spacing in the weft direction is lower than the above range, during the production of the prepreg, the varnish is difficult to flow from the front to the back (or from the back to the front) of the glass cloth. In this case, the resin layer on both sides of the obtained prepreg is prone to thickness difference, and therefore the dimensional stability is prone to decrease.

[0034] The average gap spacing in the warp direction is 65~200 μm. More preferably, it is 70~195 μm, further preferably 80~180 μm, further preferably 85~170 μm, and most preferably 90~160 μm. If the average gap spacing in the warp direction is higher than the above range, the fiber opening of the glass cloth is prone to be insufficient, and therefore the prepreg is prone to pinholes. If the average gap spacing in the warp direction is lower than the above range, during the production of the prepreg, the varnish is difficult to flow from the front to the back (or from the back to the front) of the glass cloth. In this case, the resin layer on both sides of the obtained prepreg is prone to thickness difference, and therefore the dimensional stability is prone to decrease.

[0035] The average gap interval in the weft direction can be the same as the average gap interval in the warp direction, or the average gap interval in the weft direction can be greater than the average gap interval in the warp direction, or the average gap interval in the weft direction can be less than the average gap interval in the warp direction. By comparing the average gap spacing in the weft direction with that in the warp direction, the larger gap spacing can be treated as the "long side" of the cage-like opening, and the smaller gap spacing as the "short side". Furthermore, when the average gap spacing in the weft direction and the average gap spacing in the warp direction are the same, either one can be treated as the "long side" and the other as the "short side". In this embodiment, the ratio (short side / long side) of the cage-like holes is preferably 0.4 to 0.8, and particularly preferably 0.5 to 0.7. If the ratio (short side / long side) of the cage-like holes is within the above range, it is easy to suppress pinholes in the prepreg and improve the dimensional stability of the substrate.

[0036] The average area of ​​pinholes is preferably 15,000~45,000 μm², more preferably 16,000~42,000 μm², further preferably 1,700~40,000 μm², further preferably 18,000~39,000 μm², and particularly preferably 20,000~37,000 μm². If the average area of ​​pinholes in the glass cloth is within the above range, it is easy to suppress pinhole formation in the prepreg and improve the dimensional stability of the substrate.

[0037] [Surface treatment agent (silane coupling agent)] The glass yarn (including glass filaments) constituting the glass cloth is preferably surface-treated with a surface treatment agent such as a silane coupling agent. As a silane coupling agent, for example, a silane coupling agent represented by the following general formula (1) is preferred: X(R) 3-nSiY n···(1) {In formula (1), X is an organic functional group having one or more amine groups, an organic functional group having one or more unsaturated double bonds with free radical reactivity, or an organic functional group having one or more amine groups and one or more unsaturated double bonds with free radical reactivity, Y is independently an alkoxy group, n is an integer between 1 and 3, and R is independently a group selected from the group consisting of methyl, ethyl and phenyl groups}.

[0038] In the above general formula (1), X can be, for example, an organic functional group having at least one carbon-carbon double bond or other unsaturated double bond group with free radical reactivity, an organic functional group having at least one amine group, or an organic functional group having both at least one unsaturated double bond group with free radical reactivity and at least one amine group. The amine group can be, for example, a primary amine group, a secondary amine group, a tertiary amine group, or a quaternary ammonium salt. Regarding Y in the above general formula (1), as an alkoxy group, any form can be used, but for the purpose of stabilizing the glass cloth, it is preferred to be an alkoxy group with 5 or fewer carbon atoms.

[0039] As a surface treatment agent, the silane coupling agent shown in general formula (1) can be used as a single component, or two or more silane coupling agents of different X in general formula (1) can be mixed and used. Furthermore, examples of silane coupling agents shown in general formula (1) include: N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane and its hydrochloride, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropylmethyldimethoxysilane and its hydrochloride, N-β-(N-di(vinylbenzyl)aminoethyl)-γ-aminopropyltrimethoxysilane and its hydrochloride, N-β-(N-di(vinylbenzyl)aminoethyl)-N-γ-(N-vinylbenzyl)-γ-aminopropyltrimethoxysilane and its hydrochloride, N-β-(N-di(vinylbenzyl)aminoethyl)-N-γ-(N-vinylbenzyl)-γ-aminopropyltrimethoxysilane, and N-β-(N-di(vinylbenzyl)aminoethyl)-N-γ-(N-vinylbenzyl)-γ-aminopropyltrimethoxysilane, etc. Silanes and their hydrochlorides, N-β-(N-benzylaminoethyl)-γ-aminopropyltrimethoxysilanes and their hydrochlorides, N-β-(N-benzylaminoethyl)-γ-aminopropyltriethoxysilanes and their hydrochlorides, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropyltriethoxysilane, aminopropyltrimethoxysilane, vinyltrimethoxysilane, methacryloxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, and other known single components, or mixtures thereof.

[0040] [Manufacturing Method of Fiberglass Cloth] One embodiment of this invention is a method for manufacturing glass cloth. The manufacturing method includes, for example, a step of weaving glass yarn containing a plurality of glass filaments as warp and weft yarns to obtain glass cloth (weaving step). Preferably, it further includes at least one of the following steps: before the weaving step, a warping step of doubling and flattening the glass yarn, followed by coating with a sizing agent; and a step of heating and degreasing the adhesive component attached to the glass yarn after the warping step, and before, during, or after the weaving step (heating and degreasing step). Furthermore, it is preferred to further include at least one of the following steps: after the heating and degreasing step, a step of surface treating the glass surface with a surface treatment liquid (surface treatment step); and a step of opening the glass yarn after the surface treatment step. By including these steps, the insulation reliability of the glass cloth can be easily improved.

[0041] [Steps for warping glass yarn] The manufacturing method described in this embodiment may also include the following steps: flattening the glass yarn bundle; and then sizing the glass yarn (a process for applying a sizing agent to the glass yarn). This process allows the sizing agent to be applied to the glass yarn (applying a paste) while the yarn width is increased, thus facilitating the widening of the yarn width in the woven glass cloth state. In this case, it is easy to adjust the average gap interval in the weft direction of the obtained glass cloth to the aforementioned range. As a method for flattening the glass yarn bundle, for example, the following method can be used: applying pressure to the glass yarn using a clamping roller. From the viewpoint of easily suppressing the generation of fine hairs and flattening the yarn bundle, the pressure applied to the glass yarn in this case is preferably 1.0 kg / cm² to 6.0 kg / cm², more preferably 2.0 kg / cm² to 5.0 kg / cm², and even more preferably 2.5 kg / cm² to 5.5 kg / cm².

[0042] [Weaving steps of glass cloth base fabric] Glass yarn can be used as both warp and weft yarns and woven into the fabric using a loom. This allows, for example, the manufacture of a glass cloth prefabricated fabric with a plain weave structure. To suppress fine fibers during the spinning and warping of the glass yarn, the glass yarn used in the glass cloth prefabricated fabric is preferably surface-treated with a sizing agent primarily composed of starch and polyvinyl alcohol. Furthermore, in this specification, "glass cloth prefabricated fabric" refers to glass cloth before heat degreasing.

[0043] [Reduce the steps of applying sizing agents (heating and degreasing steps)] The step of reducing sizing agent can include, for example, a desizing step (heating and degreasing step) that heats the glass cloth blank at a temperature of 300°C to 1600°C. This easily reduces the amount of sizing agent in the glass. Furthermore, the heating and degreasing conditions can be adjusted according to the type of glass and the thickness of the glass cloth. By reducing the amount of residual trace amounts of sizing agent that remain physically attached to the glass surface due to thermal oxidation, the increase in the dielectric loss factor of the obtained glass cloth can be easily and effectively suppressed. The heating time can be selected from 1 minute to 72 hours, and can be adjusted appropriately according to the heating temperature and the type of glass.

[0044] Heating the glass cloth preform can be performed by heating it to a degreasing temperature range of 300°C to 1600°C, using known heating methods, heating media, heating mechanisms, heating devices, and heating components. Examples of heating methods include: (1) heating the glass cloth preform in a heating furnace; (2) bringing the glass cloth preform into contact with the heating element; and (3) bringing high-temperature steam into contact with the glass cloth preform. By heating the glass cloth preform to a degreasing temperature range of 300°C to 1600°C, organic matter adhering to the surface of the glass cloth preform can be easily and efficiently removed, or the removal time of organic matter can be shortened. Heating the glass cloth preform can be performed sequentially or continuously in a closed or open system, or a combination of closed and open systems can be used.

[0045] In the case of a closed system, from the viewpoint of using a heating method for appropriate heating, it is preferable to place the glass cloth preform inside the heating furnace, and / or from the viewpoint of storage space and heating range, it is preferable to store the glass cloth preform in a roll while heating. Furthermore, from the viewpoint of easily improving the removal efficiency of organic matter or shortening the removal time of organic matter, it is also preferable to heat the glass cloth preform while it is being moved inside the heating furnace.

[0046] In the case of an open system, from the perspective of the heated area, it is preferable to heat the glass cloth fabric while it is being transported. The transport of the glass cloth fabric can be carried out, for example, by a roll-out mechanism and a take-up mechanism, such as a roll-to-roll method.

[0047] [Fiber Opening Steps for Glass Cloth] In this step, the glass cloth undergoes a fiber-opening process. This step facilitates the improvement of resin impregnation in the glass cloth, thereby making it easier to adjust the average gap spacing in both the weft and warp directions of the obtained glass cloth to the aforementioned range. Examples of this fiber-opening process include: fiber-opening by applying water pressure to the glass cloth; fiber-opening by high-frequency vibration using water (e.g., degassed water, ion-exchanged water, deionized water, electrolyzed cation water, or electrolyzed anion water) as a medium; and processing using pressure applied by rollers. This fiber-opening process can be performed simultaneously with or after weaving. It can also be performed before or after heat degreasing, or simultaneously with heat degreasing. Furthermore, it can be performed simultaneously with or after the surface treatment step.

[0048] From the viewpoint that it is easy to adjust the average gap spacing in the weft and warp directions of the glass cloth to the aforementioned range, the fiber-opening step preferably includes the following steps: after the heating and degreasing step and before the surface treatment step, the glass cloth is washed and opened while being transported in a liquid. Furthermore, the transport speed of the glass cloth during this process is preferably 50 m / min or less. By performing the washing and fiber-opening process on the glass cloth after the heating and degreasing step and before the surface treatment step, it is easy to remove the combustion residue from the heating and degreasing process. In this case, it is easy to prevent the adhesion between filaments caused by the combustion residue acting as an adhesive. Furthermore, by performing fiber-opening before the surface treatment, it is also easy to prevent the adhesion between filaments during the surface treatment step. As a result, not only is it easy to adjust the average gap spacing in the weft and warp directions of the glass cloth, but it is also easy to improve insulation reliability.

[0049] The preferred steps for cleaning and fiber splitting the glass cloth include the following (ultrasonic cleaning step): irradiating the glass cloth in a liquid after the heating and degreasing step and before the surface treatment step with ultrasound; thereby primarily cleaning the combustion residue from the heating and degreasing process from the glass cloth and splitting the glass fibers. The preferred steps for cleaning and fiber splitting include the following: handling the glass cloth in a roll-to-roll manner in a liquid irradiated with ultrasound.

[0050] Water or organic solvents can be used as the liquid for ultrasonic cleaning, but from the perspective of safety and environmental protection, it is preferable to use a liquid with water as the main component. To improve cleaning efficiency, surfactants and pH adjusters can also be added to the cleaning liquid.

[0051] There are no particular restrictions on the temperature of the liquid used for ultrasonic cleaning, but from the perspective of improving cleaning effectiveness, a temperature of 5°C or higher is preferred. However, from a safety perspective, the temperature of the cleaning liquid is preferably below 60°C.

[0052] By moving the glass cloth in a liquid irradiated with ultrasound, the glass cloth can be irradiated with ultrasound in the liquid and then cleaned. The tension of the warp yarns during the cleaning process is preferably 30~500 N / m.

[0053] Ultrasonic cleaning can be performed using ultrasound with a frequency of 20–200 kHz. The preferred frequency is 20–50 kHz, and more preferably 20–30 kHz. Using ultrasound with a frequency of 20–200 kHz helps prevent larger defects such as fiberglass banding and facilitates cleaning.

[0054] Ultrasonic cleaning is best performed using ultrasonic power ranging from 0.07 to 3.60 W / cm². The preferred range for ultrasonic power is 0.14 to 2.16 W / cm², and further preferably 0.21 to 1.44 W / cm². Ultrasonic power of 0.07 W / cm² or higher facilitates effective cleaning, while power below 3.60 W / cm² helps prevent larger defects such as yarn fraying and ensures uniform cleaning.

[0055] During ultrasonic cleaning, the conveying speed of the glass cloth is preferably below 50 m / min, more preferably below 40 m / min, and even more preferably below 30 m / min. If the conveying speed of the glass cloth is below 50 m / min, it is easier to effectively clean and open the glass cloth or its intermediate materials. Furthermore, it is easier to suppress the generation of fine lint and loose threads caused by damage during the conveying process.

[0056] The liquid used for ultrasonic cleaning typically contains dissolved air, primarily composed of nitrogen and oxygen. The dissolved oxygen content (by mass) is preferably 1–20 ppm, more preferably 3–17 ppm, and even more preferably 4–14 ppm. By managing the dissolved oxygen content, the amount of dissolved gas can be indirectly controlled, thus facilitating the control of the ultrasonic attenuation caused by the dissolved gas. If the dissolved oxygen content is above 1 ppm, uniform fiber opening is easily achieved. If the dissolved oxygen content is below 20 ppm, good cleaning properties are easily imparted to the fibrous fabric. In other words, a uniform and good fiber opening effect is easily obtained when the dissolved oxygen content is between 1 and 20 ppm.

[0057] [Surface treatment steps for glass cloth] A surface treatment method for glass cloth can be exemplified by a method comprising the following steps: a coating step, in which the surface of the glass filament is covered with a silane coupling agent by a treatment solution containing a silane coupling agent; and a fixing step, in which the silane coupling agent is fixed to the surface of the glass filament by heating and drying. The treatment solution preferably contains 0.1% to 3.0% by mass of a silane coupling agent. Preferably, the coating step is used to almost completely cover the surface of the glass filament with the silane coupling agent.

[0058] As a method for coating the treatment solution onto glass cloth, the following methods can be used: (i) accumulating the treatment solution in a bath and immersing the glass cloth in it (hereinafter referred to as the "immersion method"); (ii) directly coating the glass cloth with the treatment solution using a roller coater, a die coater, or a gravure coater. When coating is performed using the immersion method described in (i) above, it is preferable to select an immersion time of 0.5 seconds to 1 minute for the glass cloth in the treatment solution.

[0059] The heating and drying temperature is preferably above 90°C, and more preferably above 100°C, to ensure that the silane coupling agent reacts fully with the glass. Furthermore, to prevent the deterioration of the organic functional groups of the silane coupling agent, the heating and drying temperature is preferably below 300°C, and more preferably below 200°C.

[0060] The surface treatment method for glass cloth may include the following steps: cleaning at least a portion of the silane coupling agent fixed to the surface of the glass filaments using a cleaning solution such as water; and then adjusting the amount of silane coupling agent adhering to the surface (adjustment step). Cleaning can be performed using high-pressure water spray or the like.

[0061] As a solvent for dissolving or dispersing the silane coupling agent, either water or an organic solvent can be used, but from the perspective of safety and environmental protection, water is preferred as the main solvent. As a method for obtaining a treatment solution with water as the main solvent, it is preferably one of the following methods: directly adding the silane coupling agent to water; or dissolving the silane coupling agent in a water-soluble organic solvent to prepare an organic solvent solution, and then adding the organic solvent solution to water. To improve the water dispersibility or stability of the silane coupling agent in the treatment solution, a surfactant can also be used in conjunction.

[0062] [Fiber opening step after surface treatment] In the fiber-opening step of the glass filaments after surface treatment, methods such as spraying water (high-pressure water fiber opening), vibrating cleaner, ultrasonic water, or rolling mill can be used to open the glass cloth. During this fiber-opening process, there is a tendency to increase the yarn width by reducing the tension applied to the glass cloth. Furthermore, to suppress the formation of fine fibers in the glass cloth due to the fiber-opening process, it is preferable to implement measures such as reducing friction between the glass yarn and contacting components during weaving, and optimizing and increasing the adhesion of the surface treatment agent.

[0063] [Regarding each step] The steps described above do not necessarily need to be performed in separate steps; multiple steps can be combined into one. The composition of the glass cloth usually remains unchanged before and after fiber opening. Furthermore, the manufacturing method of glass cloth can include any steps besides those described above. For example, a step for cutting the cloth into strips of a specified width can be performed after the fiber opening step. Also, if possible, the order of the above steps can be reversed.

[0064] According to the glass cloth manufacturing method described above, the average gap interval in the weft and warp directions can be easily adjusted to the above-mentioned range. Therefore, a glass cloth that can effectively suppress pinholes in the prepreg and improve the dimensional stability of the substrate can be obtained. The glass cloth of this embodiment can be used, for example, as a material for manufacturing printed wiring boards.

[0065] [Prepreg] Another embodiment of this invention is a prepreg comprising the aforementioned glass cloth and a thermosetting resin. The prepreg can be manufactured according to conventional methods. For example, a thermosetting resin varnish (also referred to as "varnish" in this specification) can be prepared, which is obtained by diluting a base resin such as epoxy resin with an organic solvent. The aforementioned glass cloth is impregnated in the thermosetting resin varnish, and the organic solvent is evaporated in a drying oven, allowing the thermosetting resin to harden to stage B (semi-hardened state). Furthermore, regarding the amount of thermosetting resin adhering to the glass cloth, it is preferable to adjust it such that the mass of the varnish solids component is 20-80% by mass relative to the total mass of the varnish solids component and the glass cloth.

[0066] Examples of matrix resins used in prepregs include: thermosetting resins such as epoxy resins, unsaturated polyester resins, polyimide resins, bismaleimide triazine (BT) resins, and cyanate ester resins; thermoplastic resins such as polyphenylene oxide (PPO) resins, polyetherimide resins, and fluoropolymers; and mixtures thereof. Additionally, resins containing inorganic fillers such as aluminum hydroxide, talc, and silica can also be used.

[0067] Printed wiring board Another embodiment of this invention is a printed wiring board comprising the aforementioned prepreg. The printed wiring board comprises one or more of the aforementioned prepregs. That is, the printed wiring board has the aforementioned glass cloth and a cured form containing a matrix resin composition impregnated in the aforementioned glass cloth. The printed wiring board of this embodiment exhibits high adhesion to the resin and excellent dielectric properties.

[0068] [Integrated circuits and electronic devices] Another embodiment of this invention is an integrated circuit and an electronic device that includes the aforementioned printed circuit board. The integrated circuit and electronic device obtained using the printed circuit board of this embodiment exhibit excellent characteristics. [Example]

[0069] The embodiments and comparative examples used to illustrate this implementation are described below. However, this implementation is not limited to the following embodiments. Unless otherwise specified, all manufacturing, measurement, and evaluation processes in the embodiments and comparative examples are conducted at room temperature (25°C) and atmospheric pressure.

[0070] [Measurement and Evaluation] [physical properties] [TEX value, number of filaments, weaving density, and thickness] According to JIS R3420, the physical properties of glass yarn and glass cloth are determined, specifically the TEX value, the number of filaments, the weaving density of warp and weft yarns (weave density), and the thickness of glass cloth.

[0071] [Average filament diameter of glass yarn] For glass yarn, a cross-section of 30 strands from an arbitrary location was obtained, and the cross-section was observed using a scanning electron microscope. The average filament diameter was calculated from the observed image, and the average filament diameter (μm) of the glass yarn was determined from this.

[0072] [Average number of filaments in glass yarn] The number of filaments is determined according to JIS R3420. The average number of filaments is then calculated based on this number.

[0073] [Warp and weft yarn width] Using a camera with a field of view of approximately 2.3 × 1.7 mm and a resolution of 2.26 μm / pixel, images were taken at 1 mm intervals along the MD or TD direction of the glass cloth. Based on the obtained data, the average yarn width (μm) of both the warp and weft yarns of the glass cloth was calculated. Then, the average yarn width (μm) was calculated using the yarn widths obtained from more than 100 glass yarns.

[0074] [Fiber opening degree of glass cloth] For the warp and weft yarns of glass cloth, the open fiber density [%] is calculated according to the following formula: Warp yarn openness [%] = {warp yarn width [μm] / (number of warp filaments [threads] × warp filament diameter [μm])} × 100 The opening density of the weft yarn [%] = {the width of the weft yarn [μm] / (the number of filaments of the weft yarn [number] × the diameter of the filaments of the weft yarn [μm])} × 100. Then, calculate the average opening density of the warp and weft yarns, and use this to determine the average opening density (%) of the glass cloth.

[0075] [The average gap between the warp and weft yarns in the glass cloth] The average gap spacing in the warp and weft directions of the glass cloth can be calculated using the following formula: The average gap between warp yarns (the gap between adjacent weft yarns) [μm] = {25000 - (weft yarn width [μm] × weft yarn density [threads / 25 mm])} / (weft yarn density [threads / 25 mm] - 1) Average gap spacing in the weft direction (gap spacing between adjacent warp yarns) [μm] = {(25000 - warp yarn width [μm] × warp yarn density [threads / 25 mm])} / (warp yarn density [threads / 25 mm] - 1).

[0076] [Average area of ​​cage-shaped openings and the ratio of the cage-shaped openings (short side / long side)] The average area of ​​the cage-like openings in the glass cloth can be calculated using the following formula: The average area of ​​the cage-like hole [μm 2] = the average gap interval in the warp direction [μm] × the average gap interval in the weft direction [μm].

[0077] The average gap interval [μm] in the warp direction and the average gap interval [μm] in the weft direction are compared. The longer one (in this embodiment, the average gap interval in the warp direction) is regarded as the long side, and the shorter one (in this embodiment, the average gap interval in the weft direction) is regarded as the short side. Then, calculate the ratio (short side / long side) in the cage-like opening according to the following formula: The ratio of the cage-shaped holes (short side / long side) = the average gap spacing [μm] in the weft direction / the average gap spacing [μm] in the warp direction.

[0078] [Dielectric constant and dielectric loss factor] According to IEC 62562, the dielectric constant and dielectric loss factor of each glass were determined. Specifically, glass plate samples were obtained and adjusted to the dimensions required for measurement using a split-cylinder resonator. These samples were then stored in a constant temperature and humidity oven at 23°C and 50%RH for at least 8 hours, followed by humidity control. Subsequently, the dielectric properties were measured at 10 GHz using a split-cylinder resonator (manufactured by EM Labs) and an impedance analyzer (manufactured by Agilent Technologies). Five measurements were performed on each sample, and the average value was calculated.

[0079] [Volume dielectric constant and volume dielectric loss factor] A glass plate with a thickness of 300 μm was prepared, which had the same kind, and the same composition as the respective glass cloth for which the dielectric loss factor was determined. Then, the volumetric dielectric constant, and volumetric dielectric loss factor at 10 GHz were determined using the same method as the above determination of the dielectric loss factor using the thickness obtained according to the thickness determination of that glass plate. In the table, the items denoting the volumetric dielectric constant as “Dk@10 GHz” and the item denoting the volumetric dielectric loss factor as “Df@10 GHz”, respectively.

[0080] [Coefficient of Thermal Expansion (CTE) of Glass] Assay was performed according to JIS R3102-1995. Specifically, a diamond cutter, and a grinder were used to process the broken glass into 4 mm × 4 mm × 20 mm samples, thereby preparing the samples for CTE assay. The obtained samples were heated at a temperature rise rate of 5°C / min, and then the elongation in the temperature range of 50~200°C was determined, according to which the thermal expansion coefficient of the glass was determined.

[0081] [Example 1] [Making of glass cloth] The glass A described in the following table was taken as the glass type, and the warp yarn was warped using a glass yarn with an average filament diameter of 3.6 μm, a filament root number of 38, and a pin number of 1.0 Z. In this case, the yarn is pressurized (held) by the clamp roller at the prescribed load on the warp yarn that has been folded at the prescribed carrying speed, thereby carrying out the flattening of the glass yarn. Here, the warping conditions for warp yarns are described below. (Warping Conditions for Warp Yarns) Transport speed of warp yarn: 60 m / min Holding load: 3.0 kg / cm

[0082] Thereafter, a sizing agent with polyvinyl alcohol (PVA) resin as the main component was allowed to attach to the glass yarn according to the following steps. That is, an aqueous solution with a concentration of 5% by mass was prepared for PVA (trade name: PVA403, manufactured by Cola Company), in which 2% by mass of hydrogenated castor oil was prepared as a lubricant, thereby obtaining a sizing agent. The pulping agent is attached to the glass yarn by allowing the temperature to be maintained at 60°C, followed by drying, thereby performing the pulping treatment. Thereafter, an air-jet shuttleless loom was used to weave glass fabric embryo fabric at a weaving density of 75 strands / mm of warp and 100 strands / mm of weft yarn. At this point, weaving was carried out in such a way that the cloth width reached 1300 mm. Furthermore, the weft yarn uses the same glass yarn as the warp yarn.

[0083] The slurry adhering to the glass surface is removed by heating the obtained glass cloth in roll form at 360°C for 72 hours (heating and degreasing step). Then, the glass cloth is moved in water at a conveying tension of 150 N and a linear speed of 30 m / min, and is irradiated with ultrasound at a frequency of 25 GHz and a power of 0.72 W / cm² to remove residue (cleaning and fiber opening step).

[0084] Next, a treatment solution was prepared by dispersing 1.0% by mass of N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane hydrochloride (manufactured by Toray Dow Corning, Z6032) in pure water adjusted to pH=3 with acetic acid. The fabric was immersed in the treatment solution, then squeezed out, and heated and dried at 130°C for 60 seconds to fix the silane coupling agent. Subsequently, the fabric was subjected to high-pressure fiber opening (a fiber opening step after surface treatment) using a sprayer at a pressure of 2.0 kg / cm², followed by drying at 130°C for 1 minute to obtain the glass cloth.

[0085] [Preparation of prepreg] An epoxy resin varnish was prepared by mixing 80 parts by weight of low-brominated bisphenol A type epoxy resin, 20 parts by weight of cresol phenolic varnish type epoxy resin, 2 parts by weight of dicyandiamide, 0.2 parts by weight of 2-ethyl-4-methylimidazolium, and 100 parts by weight of 2-methoxy-ethanol. Then, a glass cloth was impregnated in the epoxy resin varnish while being conveyed at a speed of 3 m / min. Excess varnish was scraped off the glass cloth by passing it through an adjusted slit with an epoxy resin varnish content of 68% by weight. The mixture was then dried at a drying temperature of 170°C for 1 minute and 30 seconds to obtain a prepreg.

[0086] [Ratio of the front to the back resin layers in the prepreg] The obtained prepreg was embedded in resin (Epomount base and hardener II, manufactured by Refine Tec). A cross-section of the prepreg, along with the resin, was cut out with the glass filaments having a roundness of 0.9 or higher, and then ground. This cross-section was observed using an optical microscope at magnification (e.g., 1000x) to obtain an image containing the glass cloth layer and the resin layer on top of the glass cloth. The thickness of the resin layer on the front and back sides of the prepreg was determined from this image. Then, the resin layer ratio was calculated by dividing the lower value by the higher value.

[0087] At this point, within the observation area, the region extending up to the area containing the glass filaments closest to the resin layer is designated as the "glass cloth layer," and the region closer to the resin layer than the glass cloth layer is designated as the "resin layer." The thickness of the resin layer on the front and back sides is thus determined. This operation is performed a total of 30 times, changing the measurement position on both the front and back sides, and the average value of the obtained values ​​is calculated. The ratio of the resin layer on the front to the back side in the prepreg is then determined.

[0088] [Yield rate of prepreg (suppression rate of pinhole formation)] Samples of 400 mm × 400 mm size were obtained from the prepreg. After obtaining a total of 150 samples of the above size, the number of pinholes in each sample was counted by visual inspection. Prepregs with 4 or fewer pinholes per piece were recorded as good products, and the yield rate (%) of the 150 pieces was evaluated.

[0089] [Evaluation method for dimensional stability of substrate] A 12 μm copper foil was placed on both sides of a prepreg sheet with dimensions of 340 mm in length and 340 mm in width, obtained using the prepreg fabrication method described above. The sheet was then heated and pressurized at 175°C and 3.9 MPa for 1 hour. This yielded a 1-ply substrate for dimensional stability evaluation.

[0090] On the obtained substrate, nine markings (three in the warp direction and three in the weft direction) were made at 125 mm intervals. The interval between six adjacent markings was measured in both the warp and weft directions (measurement value a). After removing the copper foil through etching, the substrate was heated at 170°C for 30 minutes. The marking interval was then measured again (measurement value b). The dimensional change rate was then calculated using the following formula: Dimensional change rate (%) = percentage of {(difference between measured value a and measured value b) / measured value a} (%).

[0091] Then, the absolute value of the difference between the maximum and minimum values ​​of the six dimensional change rates is calculated in both the warp and weft directions, and this value is taken as the "difference in dimensional change rate".

[0092] [Example 2]~[Example 3] Except for changing the items listed in the table below, such as the weave density of the glass yarn and the warp and weft yarns in the glass cloth, the glass cloth was obtained using the same method as in Example 1.

[0093] [Example 4] Except for changing the items listed in the table below, such as the weave density of the glass yarn and the warp and weft yarns in the glass cloth, and changing the warping conditions as described below, the glass cloth was obtained using the same method as in Example 1. (Conditions for warping the warp yarn) Warp speed: 60 m / min Holding load: 4.0 kg / cm² 0000 [Example 5] Except for changing the items listed in the table below, such as the weave density of the glass yarn and the warp and weft yarns in the glass cloth, the glass cloth was obtained using the same method as in Example 1.

[0094] [Example 6] Except for changing the items listed in the table below, such as the weave density of the glass yarn and the warp and weft yarns in the glass cloth, and changing the warping conditions as described below, the glass cloth was obtained using the same method as in Example 1. (Conditions for warping the warp yarn) Warp speed: 30 m / min Holding load: 4.2 kg / cm²

[0095] [Example 7] Except for changing the items listed in the table below, such as the weave density of the glass yarn and the warp and weft yarns in the glass cloth, and changing the warping conditions as described below, the glass cloth was obtained using the same method as in Example 1. (Conditions for warping the warp yarn) Warp speed: 20 m / min Holding load: 4.6 kg / cm²

[0096] [Example 8] Except for changing the items listed in the table below, such as the weave density of the glass yarn and the warp and weft yarns in the glass cloth, and changing the warping conditions as described below, the glass cloth was obtained using the same method as in Example 1. (Conditions for warping the warp yarn) Transport speed of warp yarn: 40 m / min Holding load: 3.0 kg / cm

[0097] [Comparative Example 1] The glass A described in the following table was taken as the glass type, and the warp yarn was warped using a glass yarn with an average filament diameter of 3.6 μm, a filament root number of 38, and a pin number of 1.0 Z. At this time, according to the following step sequence, the sizing agent with polyvinyl alcohol (PVA) resin as the main component was attached to the warp yarn that was merged at a carry speed of 60 m / min. That is, an aqueous solution with a concentration of 5% by mass was prepared for PVA (trade name: PVA403, manufactured by Cola Company), in which 2% by mass of hydrogenated castor oil was prepared as a lubricant, thereby obtaining a sizing agent. The pulping agent is attached to the glass yarn by allowing the temperature to be maintained at 60°C, followed by drying, thereby performing the pulping treatment. Thereafter, an air-jet shuttleless loom was used to weave glass fabric embryo fabrics at a weaving density of 103 strands / mm for warp and 108 strands / mm for weft yarn. At this point, weaving was carried out in such a way that the cloth width reached 1300 mm. Furthermore, the weft yarn uses the same glass yarn as the warp yarn.

[0098] The sizing agent attached to the glass surface was removed by heating the obtained glass cloth embryo fabric in the state of a roll at 360°C for 72 h (heating degreasing step). Following this, a treatment solution was prepared, which was obtained by dispersing a hydrochloride salt of 1.0 mass% of N-β-(N-vinylbenzylamineethyl)-γ-aminopropyltrimethoxysilane (manufactured by Toray Road Corning, Z6032) in pure water that had been adjusted to pH=3 using acetic acid. The silane coupling agent was immobilized by immersing the cloth in the treatment solution, followed by squeezing, and heating and drying at 130°C for 60 seconds. Subsequently, a high-pressure opening fiber (opening step after surface treatment) was performed on the cloth using a sprayer at a pressure of 2.0 kg / cm

[0099] [Comparative Example 2] The glass A described in the following table was used as the glass type, and the warp yarn was warped using a glass yarn with an average filament diameter of 4.0 μm, a filament root number of 34, and a pin number of 1.0 Z. At this time, according to the following step sequence, the sizing agent with polyvinyl alcohol (PVA) resin as the main component was attached to the warp yarn that was merged at a carry speed of 60 m / min. That is, an aqueous solution with a concentration of 5% by mass was prepared for PVA (trade name: PVA403, manufactured by Cola Company), in which 2% by mass of hydrogenated castor oil was prepared as a lubricant, thereby obtaining a sizing agent. The pulping agent is attached to the glass yarn by allowing the temperature to be maintained at 60°C, followed by drying, thereby performing the pulping treatment. Thereafter, an air-jet shuttleless loom was used to weave the glass fabric embryo at a weaving density of 105 strands / mm of warp and 105 strands / mm of weft yarn. At this point, weaving was carried out in such a way that the cloth width reached 1300 mm. Furthermore, the weft yarn uses the same glass yarn as the warp yarn.

[0100] The sizing agent attached to the glass surface was removed by heating the obtained glass cloth embryo cloth in the state of a roll at 400°C for 40 hours (heating degreasing step). Following this, a treatment solution was prepared, which was obtained by dispersing a hydrochloride salt of 1.0 mass% of N-β-(N-vinylbenzylamineethyl)-γ-aminopropyltrimethoxysilane (manufactured by Toray Road Corning, Z6032) in pure water that had been adjusted to pH=3 using acetic acid. The silane coupling agent was immobilized by immersing the cloth in the treatment solution, followed by squeezing, and heating and drying at 130°C for 60 seconds. Subsequently, a high-pressure opening fiber (opening step after surface treatment) was performed on the cloth using a sprayer at a pressure of 10 kg / cm

[0101] [Comparative Example 3] The glass cloth was obtained using the same method as in Example 1 except that the glass yarn was not flattened by means of a clamp roll during the warping of the warp yarn, and the purge-opening step was not performed.

[0102] [Compare Example 4] Glass cloth was obtained using the same method as in Comparative Example 3, except for the high-pressure fibre opening after no surface treatment (the opening fibre step after surface treatment).

[0103] [Compare Example 5] The same method as in Example 1 was utilized to obtain the glass cloth, except to make changes to the items noted in the following table as shown in the table below, except for the woven density of the glass yarn, and the warp yarn in the glass cloth, and the weft yarn.

[0104] [Comparative Example 6] The items listed in the table below, such as the weave density of the glass yarn and the warp and weft yarns in the glass cloth, were changed as shown in the table below. The glass yarn was not flattened by the clamping roller during the warping of the warp yarn, and the cleaning and fiber opening step was not performed. Otherwise, the glass cloth was obtained by the same method as in Example 1.

[0105] The results related to the measurement and evaluation are shown in the table below. In the table, the yield of the prepreg (the rate of suppression of pinhole formation) can be confirmed based on the "Yield Rate" item, and the dimensional stability of the substrate can be confirmed based on the "Difference in Dimensional Change Rate" item. Here, if a prepreg with excellent dimensional stability is used, it is easy to manufacture a substrate with excellent dimensional stability. Therefore, in examples where the "Difference in Dimensional Change Rate" result of the substrate is good, it is inferred that the prepreg used as its raw material also has excellent dimensional stability.

[0106] [Table 1] Table 1 Glass A Glass B Glass C Glass D Glass E Glass composition SiO 2 wt% 53 54 >99 65 53.0 B 2O 3 wt% 8 16 - - 20.0 Al₂O₃ wt% 15 18 - twenty four 15.0 CaO wt% twenty one 2 - - 4 MgO wt% 2 2 - 11 4 Volumetric properties Dk@10 GHz μm 6.8 4.6 3.8 4.9 4.8 Df@10 GHz root 0.0061 0.0039 0.0002 0.00068 0.0025 CTE ppm / ℃ 5.6 2.7 0.5 2.8 3.3

[0107] [Table 2] Table 2 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Glass yarn warp yarn Types of glass - A B C D E B C B Average filament diameter μm 3.6 3.6 3.6 3.6 3.6 3.3 3.3 3.3 Number of filaments root 38 38 38 38 38 30 30 30 TEX g / 1000 m 1.0 0.9 0.9 1.0 0.9 0.6 0.6 0.6 weft yarn Types of glass - A B C D E B C C Average filament diameter μm 3.6 3.6 3.6 3.6 3.6 3.3 3.3 3.3 Number of filaments root 38 38 38 38 38 30 30 30 TEX g / 1000 m 1.0 0.9 0.9 1.0 0.9 0.6 0.6 0.6 Fiberglass cloth Fabric density warp yarn Root / 25mm 75 83 83 75 80 93 93 80 weft yarn Root / 25mm 100 94 94 100 90 100 100 90 warp density / weft density - 0.8 0.9 0.9 0.8 0.9 0.9 0.9 0.9 Glass cloth properties thickness μm 9.0 9.0 9.0 9.0 9.0 8.0 8.0 7.0 quality g / m 2 7.1 6.7 6.0 6.7 6.0 4.9 4.4 4.3 Yarn width warp yarn μm 120 127 123 130 114 96 99 84 weft yarn μm 157 150 150 153 164 113 109 99 Open fiber density warp yarn % 88 93 90 95 83 97 100 85 weft yarn % 115 110 110 112 120 114 110 100 average % 102 102 100 104 102 106 105 93 Average gap spacing in the weft direction μm 216 176 180 206 201 175 172 231 Average gap spacing in the warp direction μm 94 117 117 98 115 139 143 181 Cage-shaped hole Average area μm 2 20205 20555 21039 20151 23148 24196 24466 41805 short side / long side μm 0.4 0.7 0.6 0.5 0.6 0.8 0.8 0.8 Prepreg Yield % 93 99 99 94 95 100 100 90 The ratio of resin layers on the front to the back - 1.0 1.1 1.1 1.0 1.0 1.1 1.1 1.0 Substrate characteristics Difference in the rate of change of size via % 0.013 0.016 0.015 0.014 0.014 0.016 0.016 0.012 Latitudinal % 0.013 0.016 0.015 0.014 0.014 0.016 0.016 0.012 average % 0.013 0.016 0.015 0.014 0.014 0.016 0.016 0.012

[0108] [Table 3] Table 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Glass yarn warp yarn Types of glass - A A A A A A Average filament diameter μm 3.6 4.0 3.6 3.6 3.6 3.6 Number of filaments root 38 34 38 38 38 38 TEX g / 1000 m 1.0 1.1 1.0 1.0 1.0 1.0 weft yarn Types of glass - A A A A A A Average filament diameter μm 3.6 4.0 3.6 3.6 3.6 3.6 Number of filaments root 38 34 38 38 38 38 TEX g / 1000 m 1.0 1.1 1.0 1.0 1.0 1.0 Fiberglass cloth Fabric density warp yarn Root / 25mm 103 95 75 75 48 75 weft yarn Root / 25mm 108 95 100 100 100 70 warp density / weft density - 1.0 1.0 0.8 0.8 0.5 1.1 Glass cloth properties thickness μm 10.0 12.0 10.0 12.0 9.0 9.5 quality g / m 2 8.6 8.3 7.1 7.1 6.0 5.9 Yarn width warp yarn μm 116 116 93 55 97 93 weft yarn μm 150 171 150 96 150 150 Open fiber density warp yarn % 85 85 68 40 71 68 weft yarn % 110 126 110 70 110 110 average % 98 106 89 55 91 89 Average gap spacing in the weft direction μm 127 149 244 282 433 244 Average gap spacing in the warp direction μm 81 93 101 156 101 210 Cage-shaped hole Average area μm 2 10298 13835 24484 43994 43499 51064 short side / long side μm 0.6 0.6 0.4 0.6 0.2 0.9 Prepreg Yield % 100 100 88 81 60 50 The ratio of resin layers on the front to the back - 1.2 1.1 1.0 0.9 1.0 1.0 Substrate characteristics Difference in the rate of change of size via % 0.019 0.018 0.011 0.009 0.031 0.011 Latitudinal % 0.022 0.021 0.021 0.017 0.026 0.013 average % 0.021 0.019 0.016 0.013 0.029 0.012

[0109] Based on the results in the table above, it is clear that, according to the embodiments, a prepreg and a printed wiring board that can achieve excellent dimensional stability and a glass cloth that can suppress pinholes in the prepreg can be provided. In particular, according to the embodiment, it is specified that both the "difference in the rate of change of dimensions in the warp direction" and the "difference in the rate of change of dimensions in the weft direction" are below a specified value. [Industrial Applicability]

[0110] This invention is suitable for applications related to glass cloth, prepregs, and printed wiring boards.

Claims

1. A glass cloth comprising glass yarn as warp and weft, wherein the weaving density of the warp and weft is 50 to 110 yarns / 25 mm, the thickness of the glass cloth is 20 μm or less, and the average gap spacing in the weft direction and the warp direction forming the cage-like holes is 162 to 240 μm and 65 to 200 μm, respectively.

2. The glass cloth as requested in item 1, wherein the TEX value of the glass yarn is 0.2 to 2.0 g / 1000 m.

3. The glass cloth as requested in item 1 or 2, wherein the average area of ​​the cage-like pores is 15,000 to 45,000 μm².

4. The glass cloth as claimed in claim 1 or 2, which contains the aforementioned cage-like pores with an area of ​​15,000 to 45,000 μm².

5. The glass cloth of claim 1 or 2, wherein the glass yarn comprises a plurality of glass filaments, the diameter of the glass filaments in the glass yarn is 2.0 to 4.5 μm, and the number of glass filaments is 10 to 50.

6. The glass cloth as requested in item 1 or 2, wherein the ratio (short side / long side) of the cage-shaped holes is 0.4 to 0.

8.

7. The glass cloth of claim 1 or 2, wherein the average open fiber ratio of the warp yarns is 70 to 110%, and / or the average open fiber ratio of the weft yarns is 90 to 140%.

8. For the glass cloth of request item 1 or 2, wherein the ratio of the glass yarn (warp density / weft density) is less than 1.

0.

9. The glass cloth of claim 1 or 2, wherein the glass yarn has been surface-treated with a silane coupling agent.

10. The glass cloth of claim 9, wherein the silane coupling agent comprises a silane coupling agent represented by the following general formula (1): X(R) 3-nSiY n・・・(1) (where X is an organic functional group having one or more amine groups, an organic functional group having one or more unsaturated double bonds with free radical reactivity, or an organic functional group having one or more amine groups and one or more unsaturated double bonds with free radical reactivity, Y is independently alkoxy, n is an integer from 1 to 3, and R is independently selected from the group consisting of methyl, ethyl, and phenyl groups).

11. A prepreg comprising a glass cloth as claimed in claim 1 or 2, and a thermosetting resin.

12. A printed wiring board comprising a prepreg as claimed in claim 11.

13. An integrated circuit comprising a printed wiring board as claimed in claim 12.

14. An electronic machine comprising a printed wiring board as claimed in claim 12.