JPH06344503A - Production of laminated sheet and composite film for laminated sheet - Google Patents

Abstract

PURPOSE:To produce a laminated sheet of a low dielectric constant enhanced in the thickness accuracy, reduced in the coefficient of linear expansion in a thickness direction, excellent in solder heat resistance, reduced in the mixing with foreign matter and enhanced in bonding strength. CONSTITUTION:A base material 1 is impregnated with a dispersion of a PTFE resin 2 and the impregnated base material is dried at a temp. lower than the m.p. of the PTFE resin 2 and impregnation and drying are repeated to form a non-sintered prepreg 3 holding a necessary amt. of the resin while a composite film 6 for a laminated sheet having a two-layered structure consisting one layer composed of a PTFE resin and other layer formed from fluororesin 5 whose m.p. is lower than that of the PTFE resin 4 is formed. A metal foil 23 is arranged on at least the single outer layer of the non-sintered prepreg 3 through the composite film 6 and the whole is pressed at a temp. higher than the melting points of the PTFE resins 2,4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a laminate such as a low dielectric constant laminate used as a high frequency printed wiring board, and a composite film for a laminate.

[0002]

2. Description of the Related Art Conventionally, as a method for manufacturing a laminated plate, there are various manufacturing methods as described below. The first manufacturing method is
A base material is impregnated with a PTFE resin (polytetrafluoroethylene, tetrafluoride resin), and this is dried and fired to form a prepreg (pre-preg), and a PFA resin (4 Fluorinated ethylene / perfluoroalkyl vinyl ether copolymer resin film or FE
This is a method for producing a laminated plate by interposing a P resin (perfluoroethylene propylene resin) film, and interposing the film also between the metal foil and the prepreg arranged in the outermost layer, and carrying out lamination molding. .

According to this first manufacturing method, by interposing the film, the adhesive strength between the metal foil and the prepreg is maintained, and the adhesive force between the prepreg layers is maintained,
On the other hand, there is an advantage that the resin content ratio in the laminated plate can be adjusted. On the other hand, the above-mentioned film is generally melt-kneaded with a screw extruder and injection-molded through a T-type die.
During the manufacturing process of this film, a considerable amount of metal particles and metal powder are mixed in the film, and since the metal particles and metal powder have conductivity, they cause a short circuit of the printed circuit board, a disconnection, etc. There was a problem that it was difficult to use.

In the second manufacturing method, the base material is impregnated with the first fluororesin, dried and fired, then impregnated with PFA or FEP as the second fluororesin, dried and fired. In this method, a metal foil is placed on the outermost layer of the formed prepreg and then laminated forming is performed to produce a laminated plate.

According to this second manufacturing method, the first fluororesin impregnated in the base material is dried and then baked at a temperature above the melting point of the resin. Thus, when the fluororesin is baked above the melting point, Since the surface energy is low and the wettability is extremely deteriorated, even if an attempt is made to hold PFA or FEP on the fluororesin, the PFA or FEP is removed during the drying and baking steps, and a uniform and highly accurate film is formed. It is difficult to obtain a laminated board with stable performance because the adhesive strength between the prepreg and the metal foil, the mutual adhesive strength between the prepregs, and the resin content are partially different and the characteristic values vary. was there.

The third manufacturing method is to form a fluororesin layer on the surface of a cloth-like substrate, form a prepreg in the vicinity of the surface of the fluororesin layer which is unsintered, and apply a metal foil to the surface of the prepreg. After arranging, it is a method of manufacturing a laminated board by heating and pressurizing and adhering the above metal foil to the prepreg.

According to the third manufacturing method, the fluororesin layer impregnated in the cloth-like base material is unsintered only in the vicinity of the surface thereof, and the core portion of the base material and the vicinity of the base material are sintered. According to this third manufacturing method, there is an advantage that the adhesive strength between the prepreg and the metal foil can be secured to some extent, but on the other hand, in a large-sized laminated plate, it is difficult to obtain a uniform adhesive force over the entire surface, In the case of a laminate with a large variation and a low resin content, the chemical solution penetrates from the resin surface after the metal foil is removed by etching during circuit formation, and the solder heat resistance is poor and the metal foil swells. There is a problem that the defect of occurs. In addition, since a sintered layer and a non-sintered layer are mixed in the prepreg, there is a problem that defects such as warp and twist are likely to occur when the laminated plate is thin.

A fourth manufacturing method is to impregnate a cloth base material with PFA or FEP, dry and fire the prepreg to form a prepreg, place a metal foil on the prepreg, and form a laminate to laminate the laminate. Is a method of manufacturing.

According to the fourth manufacturing method, the adhesive strength between the prepreg and the metal foil, the mutual adhesive strength between the prepregs, and the adhesive strength between the cloth base material and the fluororesin of PFA or FEP are all stable. On the other hand, since PFA or FEP has a low viscosity and a large fluidity at a temperature higher than its melting point, PFA or FEP has a high flowability during the heating and pressurizing step during lamination molding.
There is a problem that P easily flows, and as a result, the thickness accuracy of the laminated plate deteriorates, and the cost of PFA or FEP is higher than that of PTFE.

In the fifth method, the base material is impregnated with the first fluororesin, dried and sintered, and the second fluororesin having a lower melting point than the first fluororesin for the upper layer. To form a prepreg, and after placing a metal foil on the prepreg, laminate molding is performed under a temperature condition that is lower than the melting point of the first fluororesin and higher than the melting point of the second fluororesin. This is a method for producing a laminated board.

According to the fifth manufacturing method, since the above-mentioned first fluororesin exhibits cushioning property due to the shape memory property peculiar to the resin at the time of laminating and pressurizing the laminated plate, the characteristics of the laminating plate may vary. In addition to being stable, since the first fluororesin is fired at a temperature equal to or higher than the melting point of the first fluororesin during firing, the surface energy is low and the wettability is deteriorated. Even if the second fluororesin is held, there is a problem that it becomes difficult to form a uniform film with high accuracy because it falls off during the drying and baking steps.

On the other hand, for example, in order to obtain a low dielectric constant substrate having a relative dielectric constant of εr = 2.4 or less, it is necessary to form a prepreg having a high resin content, for example, 80 vol% or more. It was difficult to form a prepreg with a high resin content. That is, when the glass cloth base material is impregnated with the resin, and then dried and sintered repeatedly, the resin shrinks in the resin sintering step described above, so that it becomes possible to thickly coat the resin on the glass cloth base material. However, by repeating the above operation, the base material cannot withstand the shrinkage force and is deformed into a wavy shape, so that unevenness in thickness is generated in the formed prepreg, and the thickness accuracy is deteriorated.

Therefore, conventionally, as seen in the above-described first manufacturing method, there is a method of increasing the resin content by interposing a PFA film or FEP film between each layer and between the prepreg and the metal foil. However, according to such a conventional method, as described above, a metal short piece or a metal powder is mixed into the PFA film or the FEP film, which causes a trouble such as a short circuit or a disconnection of a circuit. Further, when the PFA film and the FEP film are frequently used, it is easy to reduce the dielectric constant of the laminated plate, but on the other hand, the bending elastic modulus is lowered and the thermal expansion coefficient is increased, so that the laminated plate itself is weakened.

[0014]

The invention according to claim 1 of the present invention is such that after impregnation of the PTFE resin dispersion into the substrate, it is dried under a low temperature condition not exceeding the melting point of the PTFE resin, and this unsintered In this state, impregnation and drying are repeated to form an unsintered prepreg having a required resin retention amount, and the resin amount is adjusted with the unsintered prepreg, and a composite film having an ultrathin two-layer structure is used to form a laminated plate. By manufacturing, the thickness accuracy is high, the linear expansion coefficient in the thickness direction is small, and the solder heat resistance is excellent, the inclusion of foreign matter is small, and further, the adhesion strength can be improved. It is intended to provide a method for manufacturing a laminated board.

According to a second aspect of the present invention, there is provided a PTFE resin formed by a casting method and the PTFE resin.
By using a two-layer composite film with a low melting point fluororesin relative to the resin, there is no mixing of metal powder or carbonized fine powder,
It is an object of the present invention to provide a composite film for a laminate, which can have an ultrathin structure of 10 μm or less.

In addition to the object of the invention described in claim 2, the invention described in claim 3 of the present invention can standardize the manufacturing process of the prepreg by selecting various kinds of composite films having a two-layer structure. It is an object of the present invention to provide a composite film that can be laminated.

In the invention according to claim 4 of the present invention, even when the secondary molding is carried out when the laminated board is made into multiple layers, there is no gap between the layers or flow of the circuit part, that is, so-called swimming phenomenon, and the circuit part and the composite film are formed. It is an object of the present invention to provide a method for producing a laminated plate, which is excellent in solder heat resistance, thermal shock resistance, and dimensional stability and can be formed into multiple layers without forming voids between them.

According to the invention of claim 5 of the present invention, in addition to the object of the invention of claim 4, an unsintered prepreg is interposed between the composite films to arbitrarily set the interlayer thickness of the circuit. An object of the present invention is to provide a method for manufacturing a laminated plate that can be set.

In the invention according to claim 6 of the present invention, in addition to the object of the invention according to claim 4, a sintered prepreg is provided between the composite films to arbitrarily set the interlayer thickness of the circuit. It is an object of the present invention to provide a method for manufacturing a laminated plate that can be manufactured.

In the invention according to claim 7 of the present invention, even when secondary molding is carried out when the laminated board is made into multiple layers, there is no gap between layers or flow of the circuit part, so-called swimming phenomenon, and the circuit part and the composite film are formed. By forming a thermosetting prepreg between the composite films, in addition to having excellent heat resistance, thermal shock resistance and dimensional stability of solder without forming voids between The thickness of the circuit layer can be set arbitrarily, and the thermosetting prepreg described above is used to improve the rigidity of the entire laminated board, and is applied to a test board where compression and restoring forces are repeatedly applied. However, it is an object of the present invention to provide a method for manufacturing a laminated plate that can improve durability and can be attached to a chassis or the like after mounting components.

In addition to the object of the invention described in claim 7, the invention described in claim 8 of the present invention can standardize the manufacturing process of the prepreg by selecting various kinds of composite films having a two-layer structure. An object of the present invention is to provide a method for producing a laminated board using the composite film for laminated boards that can be used.

[0022]

According to a first aspect of the present invention, a base material is impregnated with a PTFE resin dispersion and dried at a low temperature relative to the melting point of the PTFE resin,
A two-layer structure in which the above-mentioned impregnation and drying are repeated to form an unsintered prepreg having a required resin holding amount, while one layer is made of PTFE resin and the other layer is made of fluorine resin having a low melting point with respect to the PTFE resin. After forming the composite film for laminated plate of the above, and arranging the metal foil on the outer surface of at least one side of the above-mentioned unsintered prepreg via the above composite film, PTFE
It is characterized in that it is a method for producing a laminated plate which is heated and pressed at a high temperature relative to the melting point of the resin.

The invention according to claim 2 of the present invention is the PTF.
After the E resin dispersion was deposited on the plate to form a thin layer, the two-layer structure film having the fluororesin dispersion having a low melting point with respect to the PTFE resin deposited on the thin layer surface was peeled from the plate. It is characterized by being the formed composite film for laminated plates.

In the invention according to claim 3 of the present invention, in addition to the constitution of the invention according to claim 2, the low melting point fluororesin dispersion is PFA, FEP, ETFE,
One of the ECTFE and PCTFE is a fluororesin dispersion composite film for laminated plate.

According to a fourth aspect of the present invention, the base material is impregnated with the fluororesin dispersion and then dried to form an unsintered prepreg, and a metal foil is disposed on at least one surface of the unsintered prepreg. Then, a plurality of circuit layers for inner layer and outer layer having a circuit portion heated and pressed at a temperature higher than the melting point of the fluororesin is formed, and between the plurality of circuit layers,
A composite film having a two-layer structure in which one layer is made of a PTFE resin and the other layer is made of a fluororesin having a low melting point with respect to the PTFE resin is interposed, and one layer side of the composite film is opposite to the circuit side and the other layer. And a circuit part side, the PFA or FEP interposing film is interposed between the composite film one-layer side and the facing member, and the laminated plate is heated and pressed at a temperature higher than the melting point of PTFE. It is characterized by

According to the invention of claim 5 of the present invention, in addition to the constitution of the invention of claim 4, a plurality of the composite films are provided between the plurality of circuit layers, and the plurality of composite films are provided between the plurality of circuit films. The method for producing a laminated plate is characterized in that a base material is impregnated with a fluororesin, and then a dry green prepreg is interposed.

According to a sixth aspect of the present invention, in addition to the structure of the fourth aspect of the invention, a plurality of the composite films are provided between the plurality of circuit layers, and the plurality of composite films are provided between the plurality of composite films. The method for producing a laminated plate is characterized by including a sintered prepreg obtained by impregnating a base material with a fluororesin, and then drying and sintering the same.

According to a seventh aspect of the present invention, the substrate is impregnated with the fluororesin dispersion and then dried to form an unsintered prepreg, and a metal foil is disposed on at least one surface of the unsintered prepreg. Then, a plurality of circuit layers for inner layer and outer layer having a circuit portion heated and pressed at a temperature higher than the melting point of the fluororesin is formed, and between the plurality of circuit layers,
A composite film having a two-layer structure in which one layer is made of a PTFE resin and the other layer is made of a fluororesin having a low melting point with respect to the PTFE resin is interposed, and one layer side of the composite film is opposite to the circuit side and the other layer. Side is opposed to the circuit part side and heat-sealed, and the surface opposite to the circuit side is surface-modified to a contact angle of 70 degrees or less, and the temperature between the plurality of circuit layers is lower than that of the epoxy-based or polyimide-based fluororesin. A PT that forms a composite film having a two-layer structure by interposing a thermosetting prepreg that is baked and solidified by
It is characterized in that it is a method for producing a laminated plate, which comprises heating and pressing at a low temperature with respect to the melting point of a fluororesin having a melting point lower than that of FE.

According to the invention of claim 8 of the present invention, in addition to the constitution of the invention of claim 7, the low melting point fluororesin is one of PFA, FEP, ETFE, ECTFE and PCTFE. It is characterized in that it is a method of manufacturing a laminated plate made of resin.

[0030]

According to the invention described in claim 1 of the present invention, since the unsintered prepreg having the required resin holding amount is formed by repeating the impregnation and the drying, the resin amount can be adjusted in this unsintered prepreg. It can be done, and it is very thin 2
Since a laminated board is manufactured using a composite film having a layered structure,
This composite film can be used for bonding without being used for adjusting the amount of resin, has high thickness accuracy, has a small linear expansion coefficient in the thickness direction, and is excellent in solder heat resistance, and has less foreign matter mixed in. There is an effect that the adhesive strength can be improved and a low dielectric constant laminate having a large amount of resin held can be manufactured.

According to the second aspect of the present invention,
The composite film for laminated plate formed by the casting method may be a film having a two-layer structure of PTFE resin and fluororesin having a low melting point with respect to the PTFE resin,
There is an effect that a metal powder and a carbonized fine powder are not mixed in, the electric insulation is excellent, and an extremely thin structure of 10 μm or less can be formed.

According to the invention of claim 3 of the present invention,
In addition to the effect of the invention of claim 2, the PTFE resin (melting point 327 ° C.) that constitutes one layer of the composite film is made of PFA (melting point 31
0 ° C tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer), FEP (tetrafluoroethylene hexafluoropropylene copolymer having a melting point of 275 ° C), ETFE (tetrafluoroethylene / ethylene copolymer having a melting point of 270 ° C), ECTFE (Chlorotrifluoroethylene / ethylene copolymer having a melting point of 245 ° C), P
Since it is possible to select from various low melting point fluorocarbon resins such as CTFE (polychlorotrifluoroethylene having a melting point of 220 ° C.), it is possible to obtain various types of ultra-thin composite films having a two-layer structure. This has the effect of standardizing the manufacturing process.

According to the invention of claim 4 of the present invention,
A composite film is interposed between a plurality of circuit layers having a circuit portion, one side of the composite film made of PTFE resin is an anti-circuit side, and the other layer side made of a fluororesin having a low melting point with respect to the PTFE resin is a circuit side. Since it is manufactured by arranging it in a multi-layered structure, the voids between the circuit part of the circuit layer and the composite film can be filled with the melt flow of the low melting point fluororesin even if the secondary molding is performed when the laminated board is made into multiple layers. The gap between the layers and the flow of the circuit portion, so-called swimming phenomenon, can be prevented by the PTFE resin on one side of the composite film.

As a result, even if the laminated plate is made into a multi-layer, there is no gap between the layers or flow of the circuit portion (swimming phenomenon), no void is formed between the circuit portion and the composite film, and the circuit is not formed. By producing a layer from the above-mentioned unsintered prepreg, solder heat resistance, thermal shock resistance, excellent dimensional stability,
In addition, there is an effect that it can be multi-layered.

According to the invention of claim 5 of the present invention,
In addition to the effect of the invention described in claim 4, since the unsintered prepreg is interposed between the plurality of composite films, there is an effect that the unsintered prepreg can arbitrarily set the interlayer thickness of the circuit. is there.

According to the invention of claim 6 of the present invention,
In addition to the effect of the invention described in claim 4, since the sintered prepreg is provided between the plurality of composite films, there is an effect that the interlayer thickness of the circuit can be arbitrarily set by the sintered prepreg.

According to the invention of claim 7 of the present invention,
A composite film is interposed between a plurality of circuit layers having a circuit portion, one side of the composite film made of PTFE resin is an anti-circuit side, and the other layer side made of a fluororesin having a low melting point with respect to the PTFE resin is a circuit side. Since it is manufactured by arranging it in a multi-layered structure, the voids between the circuit part of the circuit layer and the composite film can be filled with the melt flow of the low melting point fluororesin even if the secondary molding is performed when the laminated board is made into multiple layers. In addition to preventing the gap between layers and the flow phenomenon of the circuit part, so-called swimming phenomenon, by the PTFE resin on the one side of the composite film, the thermosetting prepreg is provided between the plurality of composite films.
The thermosetting prepreg allows the interlayer thickness of the circuit to be arbitrarily set, and the interposition of the thermosetting prepreg can improve the rigidity of the entire laminated plate. Even if it is applied to a test board that is repeatedly biased, its durability can be improved sufficiently, and the above-mentioned thermosetting prepreg is used as a mounting seat to mount the laminated board to the chassis etc. after mounting the components. Therefore, there is an effect that the laminated plate can be fixed with screws.

In addition, since the opposing surface of the composite film which is in contact with the thermosetting prepreg is surface-modified to a contact angle of 70 degrees or less, both of these (thermosetting prepreg and composite film) are used.
There is an effect that the bondability of can be improved.

According to the invention of claim 8 of the present invention,
In addition to the effect of the invention described in claim 7, the fluororesin constituting the other layer with respect to the PTFE resin (melting point 327 ° C.) constituting one layer of the composite film is PFA, FEP,
Since it is possible to select from various low melting point fluororesins such as ETFE, ECTFE, and PCTFE, it is possible to obtain various kinds of ultra-thin composite films having a two-layer structure. Therefore, thermosetting prepregs and unsintered prepregs are used. There is an effect that the manufacturing process of the laminated plate can be standardized.

[0040]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. The drawing shows a method for manufacturing a laminated plate and a composite film for a laminated plate. First, as shown in FIG. 1, a glass cloth substrate 1 having a basis weight of 48 g / m ² is coated with PTFE resin 2, specifically PTFE.
A resin dispersion is impregnated, and the PTFE resin 2 is dried at a melting point of 327 ° C. at a low temperature of 305 ° C. to hold the unsintered resin on the glass cloth substrate 1. Such impregnation and drying treatment under low temperature conditions are repeated to form a plurality of layers of the unsintered prepreg 3 having a resin retention amount within the range of 80 to 96 vol%, for example, 90 vol%.

On the other hand, as shown in FIG. 3, one layer of the PTFE resin 4 and the other layer of the fluororesin 5 having a low melting point with respect to the PTFE resin 4 are prepared by the casting method using the apparatus for producing a laminated plate composite film shown in FIG. The composite film 6 having the ultra-thin and two-layer structure formed in 1 is formed. Here, as the above-mentioned low melting point fluororesin 5, PFA, FEP, ETFE,
One of ECTFE and PCTFE, eg PFA
Is selected.

The above-described manufacturing apparatus shown in FIG. 2 stores a carrier 7 made of a stainless thin plate (specifically, SUS foil) which moves between the feeding position A and the winding position B, and a PTFE resin dispersion 8. The first container 9, the second container 11 storing the PFA resin dispersion 10, the first heaters 12 and 12 for heating, and the second heaters 13 and 13
And guide rollers 14 to 22 arranged at necessary positions.

Then, the carrier 7 made of SUS foil is conveyed into the PTFE resin dispersion 8 of the first container 9, the PTFE resin dispersion 8 is adhered (coated) on both surfaces of the carrier 7, and then the carrier 7 described above. Is dried between the first heaters 12 and 12 at, for example, 370 ° C., and then the carrier 7 coated with the PTFE resin 4 on both sides is conveyed into the PFA resin dispersion 10 of the next second container 11 to remove the PTFE resin 4 PF on the surface of
A resin dispersion 10 is adhered (coated), then the above-mentioned carrier 7 is dried between the second heaters 13 and 13, and then the above-mentioned two-layer composite film 6 is removed from the carrier 7 at the peeling position C. When peeled off, an extremely thin composite film 6 having an isotropic property of 10 μm or less can be manufactured.

Here, the above-mentioned composite film 6 has a thickness of the PTFE resin 4 shown in FIG.
Since the thickness of the low melting point fluororesin 5 such as A can be adjusted in the range of 3 to 20 μm, the composite film 6 having a minimum thickness of 7 μm can be obtained.

In the manufacturing apparatus of FIG. 2, the container and the heater have a front and rear two-stage structure. However, in the manufacturing apparatus having only one side and one step, the PTFE resin 4 is coated on the SUS foil and the PTFE resin after peeling is coated. 4 may be coated with a PFA resin.

Further, since the PTFE resin 4 is first coated on the carrier 7 made of SUS foil, the releasability at the peeling position C is good and the surface of the PTFE resin 4 is coated with the PFA resin. The adhesiveness to the PTFE resin 4 becomes good.

A plurality of layers of the green prepreg 3 are formed,
For example, four layers are superposed, and C having a thickness of about 35 μm as a metal foil is formed on the upper and lower outer layers with the above-mentioned composite films 6 and 6 interposed therebetween.
For the one in which u foils 23, 23 are arranged, the above PTFE
As a result of lamination molding under the conditions of the temperature of 380 ° C., which is higher than the melting point 327 ° C. of the resins 2 and 4, and the surface pressure of 3.4 MPa and the pressurizing time of about 60 minutes, the thickness is as shown in FIG. A double-sided copper foil-clad laminate 24 (Example product in the following Table 1) having a thickness of 0.8 mm and a relative permittivity εr = 2.32 could be manufactured.

On the other hand, as a comparative example, a glass cloth substrate having a basis weight of 48 g / m ² was impregnated with PTFE resin dispersion, dried and then sintered at 380 ° C. The impregnation, drying and sintering were repeated to maintain a resin retention amount of 75 vol. % Sintered prepreg is formed, and the conventional PFA film (thickness of about 25 μm is provided between the two sets of two layers of the sintered prepreg and between the two sets of one set of the sintered prepreg and the Cu foil having a thickness of about 35 μm, respectively. ) Is placed under the conditions of a high temperature of 380 ° C., a surface pressure of 3.4 MPa, and a pressing time of about 60 minutes to perform laminate molding, and the overall thickness is 0.8 mm and the relative permittivity εr = A double-sided copper foil-clad laminate of 2.6 (Comparative Product 1 in Table 1 below) was produced.

Similarly, as a comparative example, a glass cloth substrate having a basis weight of 48 g / m ² was impregnated with PTFE resin dispersion, dried and then sintered at 380 ° C. This impregnation, drying and sintering were repeated to maintain the resin retention amount. A total of three layers of 80 vol% sintered prepregs were formed, and the conventional PFA film (thickness: 50 μm) was interposed between each of these sintered prepregs and between the sintered prepreg and a Cu foil having a thickness of about 35 μm. Then, under high temperature conditions of 380 ° C., lamination molding was performed under surface pressure of 3.4 MPa and pressurization time of about 60 minutes, and the total thickness was 0.6 mm and the relative permittivity εr = 2.33. A double-sided copper foil-clad laminate (Comparative Product 2 in Table 1 below) was produced.

The following Table 1 shows the results of various measurements and tests performed on the above-described example product, comparative product 1 and comparative product 2.

[0051]

[Table 1]

As is clear from Table 1 above, in the case of the example product, the variation R in plate thickness (where R is the value obtained by subtracting the minimum dimension from the maximum dimension) is as small as 0.012 mm, and the solder heat resistance is also good. The linear expansion coefficient was 180 × 10 ⁻⁶ / k, which was a good value. Note that x in Table 1 above indicates the plate thickness.

In summary, according to the manufacturing method of this embodiment (corresponding to claim 1), the impregnation and the drying are repeated to form the unsintered prepreg 3 having the required resin holding amount (for example, 90 vol%). The amount of resin can be adjusted in this unsintered prepreg 3, and since the laminated plate 24 is manufactured using the composite film 6 having an ultrathin two-layer structure, the composite film 6 can be used for adjusting the amount of resin. Instead, it can be used for bonding. As a result, the thickness accuracy is high, the linear expansion coefficient in the thickness direction is small, the solder heat resistance is excellent, the inclusion of foreign matter is small, and the adhesive strength can be improved. There is an effect that the laminated plate 24 having a dielectric constant can be manufactured.

The composite film 6 for laminates formed by the casting method of the above-described embodiment (corresponding to claims 2 and 3) comprises the PTFE resin 4 and the fluororesin 5 having a low melting point with respect to the PTFE resin 4. A film having a two-layer structure can be formed, and since metal powder and carbonized fine powder are not mixed in, it is excellent in electrical insulation and has an effect that an extremely thin structure of 10 μm or less can be formed.

Further, the low melting point fluororesin 5 constituting another layer in addition to the PTFE resin 4 constituting one layer of the composite film 6 is made of PFA, FEP, ETFE, ECTF.
Since it is possible to select from various kinds of low melting point fluororesins such as E and PCTFE, it is possible to obtain various kinds of ultra-thin composite films 6 having a two-layer structure, and thus standardize the manufacturing process of the above-mentioned unsintered prepreg 3. There is an effect that can be.

FIG. 4 shows another embodiment (corresponding to claim 4) of a method for manufacturing a laminated plate, in which a glass cloth substrate 25 is impregnated with a fluororesin dispersion, for example, a dispersion of PTFE resin 26, and then dried. However, the resin retention amount is 60 to 7
0 vol% of unsintered prepreg 27 is formed, and Cu foils 28, 28 are formed on both sides of at least one unsintered prepreg 27.
Is placed at a temperature higher than the melting point of the PTFE resin 26 (for example, 3
A plurality of circuit layers G, G for outer layers, which are heated and pressed at 80 ° C.), are formed, and Cu foils 28, 28 on one surface of the circuit layers G, G are etched as shown in FIG. Form a circuit pattern.

Next, between the above-mentioned plurality of circuit layers G, G, one layer is made of PTFE resin 4, and the other layer is made of fluororesin 5 having a low melting point with respect to the PTFE resin 4, and thus has an extremely thin two-layer structure. The same composite films 6 and 6 as described above are provided, and the PTFE resin 4 side of these composite films 6 and 6 faces the non-circuit part side and the low melting point fluororesin 5 side faces the circuit part 29 side, and An intervening film 30 of PFA or FEP (film used as a fluidized bed) is interposed between the composite films 6 and 6, and heated and pressed at a temperature higher than the melting point of PTFE (for example, 380 ° C.) to manufacture a multilayer printed wiring board 31. .

In this way, the composite film 6 is interposed between the plurality of circuit layers G having the circuit portion 29, and the one side of the composite film 6 made of the PTFE resin 4 is the opposite circuit side, and P is the opposite side.
Since the other layer side made of the fluororesin 5 having a low melting point with respect to the TFE resin 4 is disposed on the side of the circuit portion 29 for manufacturing, even if the secondary molding is performed at the time of manufacturing the multilayer board, the structure shown in FIG. As shown in (partial cross-sectional view after completion), the gap between the circuit portion 29 of the circuit layer G and the composite film 6 can be filled with the melt flow of the low melting point fluororesin 5, resulting in a gap between layers and a circuit portion. Two
The flow phenomenon of 9 (so-called swimming phenomenon) can be prevented by the PTFE resin 4 on one side of the composite film 6.

As a result, even if the laminated plates are made into multiple layers, there is no gap between the layers or flow of the circuit portion 29 (swimming phenomenon), and no void is formed between the circuit portion 29 and the composite film 6. In addition, the production from the unsintered prepreg 27 has the effects of excellent solder heat resistance, thermal shock resistance, and dimensional stability, and also capable of forming multiple layers.

As a comparative example of this example, when only the PTFE film was used instead of the composite film 6 as shown in FIG. 6, the melt viscosity was 10 ¹⁰ to 10 ¹⁰ at 380 ° C.
Because of the high poise of ¹¹ poise, the PTFE resin does not flow into the corners of the circuit portion 29, and the void 32 (including the case where it is formed by the contraction when the PTFE resin solidifies) remains between the circuit portion 29 and the PTFE film. The adhesive strength was weak, and it was inferior to both solder heat resistance and thermal shock resistance.

Further, as a comparative example of the above-mentioned examples, when only the PFA film was used in place of the composite film 6, the melt viscosity was 10 ⁴ to 10 ⁵ poises under the condition of 380 ° C., and the melt fluidity was Since it is large, a gap between layers and a flow of the circuit portion 29 occur.

FIG. 7 shows another embodiment (corresponding to claim 4) of the method for manufacturing a laminated plate, in which the glass cloth substrate 25 is impregnated with a fluororesin dispersion, for example, a dispersion of PTFE resin 26, and then dried. However, the resin retention amount is 60 to 7
0 vol% of unsintered prepreg 27 is formed, and Cu foils 28, 28 are formed on both sides of at least one unsintered prepreg 27.
To form the circuit layer N for the inner layer, which is heated and pressed at a temperature higher than the melting point of the PTFE resin 26 (for example, 380 ° C.),
The Cu foils 28, 28 on both surfaces of the circuit layer N are etched as shown in FIG. 7 to form circuit portions 29, 29.

Circuit layers G, G for outer layers formed on the upper and lower surfaces of the circuit layer N for inner layers through the composite films 6, 6 and the interposing films 30, 30 by the same manufacturing method as in the embodiment of FIG. And was heated and pressed at 380 ° C., which is higher than the melting point of PTFE, to manufacture a multilayer printed wiring board 33.

Even with such a configuration, the same operation and effect as those of the embodiment of FIG. 4 can be obtained. Therefore, in FIG. 7, the same parts as those of FIG. Is omitted.

FIG. 8 shows still another embodiment (corresponding to claim 4) of the method for producing a laminated plate, in which the composite films 6 and 6, the interposing films 30 and 30, are formed on the upper and lower surfaces of the circuit layer N for the inner layer.
The composite films 6 and 6 and the circuit layer G for the outer layer are provided, and PT
The multilayer printed wiring board 34 is manufactured by heating and pressing at 380 ° C., which is higher than the melting point of FE.

Even with such a configuration, the same operation and effect as those of the respective embodiments of FIGS. 4 and 7 can be obtained. Therefore, in FIG. 8, the same parts as those in the previous figure are designated by the same reference numerals and symbols. , Its detailed description is omitted.

FIG. 9 shows still another embodiment (corresponding to claim 5) of the method for manufacturing a laminated board, in which a plurality of composite films 6 and 6 are provided between a plurality of circuit layers G for outer layers. ,
Between the composite films 6 and 6, after impregnating the glass cloth base material 35 with a dispersion of PTFE resin 36, for example,
A dry unsintered prepreg 37 (used as an electric insulating layer) is interposed, and interposing films 30, 30 are provided on both upper and lower surfaces of this unsintered prepreg 37, and a multilayer printed wiring is manufactured by the same manufacturing method as described above. The plate 38 is manufactured.

With such a structure, there is an effect that the green thickness of the circuit can be arbitrarily set by the above-mentioned green prepreg 37. In addition, in other respects, the same operation and effect as those of the respective embodiments described above are obtained, and therefore, FIG.
In the figure, the same parts as those in the previous figure are designated by the same reference numerals and their detailed description will be omitted.

FIG. 10 shows still another embodiment of the method for manufacturing a laminated board (corresponding to claim 5), in which the composite film 6, the interposing film 30, the unsintered prepreg are formed on the upper and lower surfaces of the circuit layer N for the inner layer. 37, the interposer film 30, the composite film 6, and the circuit layer G for the outer layer are respectively arranged in this order, and the multilayer printed wiring board 39 is manufactured by heating and pressing at 380 ° C., which is higher than the melting point of PTFE.

Even with this configuration, the same operation and effect as those of the embodiment of FIG. 9 can be obtained. Therefore, in FIG. 10, the same parts as those in the previous figure are designated by the same reference numerals and symbols, and detailed description thereof will be given. Is omitted.

FIG. 11 shows still another embodiment (corresponding to claim 6) of the method for manufacturing a laminated plate, in which a plurality of composite films 6 and 6 are provided between a plurality of outer circuit layers G and G. ,
Between the composite films 6 and 6, after impregnating the glass cloth base material 40 with a dispersion of the PTFE resin 41, for example,
A dried and sintered sintered prepreg 42 (used as an electric insulating layer) is interposed, and interposing films 30, 30 are provided on both upper and lower surfaces of this sintered prepreg 42, and a multilayer printing is performed by the same manufacturing method as described above. The wiring board 43 is manufactured.

In the case of such a construction, there is an effect that the above-mentioned sintered prepreg 42 can arbitrarily set the interlayer thickness of the circuit. In addition, in other respects, the same operation and effect as those of the above-described respective embodiments are achieved, and therefore, FIG.
In the figure, the same parts as those in the previous figure are designated by the same reference numerals and their detailed description will be omitted.

FIG. 12 shows still another embodiment of the method for manufacturing a laminated board (corresponding to claim 7) in which a plurality of composite films 6 and 6 are provided between a plurality of outer circuit layers G. A thermosetting prepreg 46 that is heat-fused and is baked and solidified at a low temperature with respect to the epoxy-based or polyimide-based fluororesin on the glass cloth base material 44 between the plurality of composite films 6 and 6.
(Also serves as an electric insulation layer), and the composite film 6, 6
The multilayer printed wiring board 47 is manufactured by heating and pressurizing at a temperature lower than the melting point of the fluororesin having a melting point lower than that of PTFE.

Here, the surfaces 4a and 4a of the composite films 6 and 6 facing the thermosetting prepreg 46 are brought into contact with water (H ₂ 0) by a plasma treatment method, a corona discharge treatment method, a chemical treatment method, or the like. Surface is preliminarily modified to an angle of 70 ° or less.

In the case of such a structure, the thermosetting prepreg 46 interposed between the plurality of composite films 6 and 6 is provided.
By using the thermosetting prepreg 46, it is possible to improve the rigidity of the entire multilayer printed wiring board 47 by using the thermosetting prepreg 46. Even if it is applied to a biased test board, the durability can be sufficiently improved, and in order to mount the multilayer printed wiring board 47 on the chassis after mounting the components, for example, each upper element G in FIG. , 6, 30 can be provided with holes for disposing screw heads, and the above-mentioned thermosetting prepreg 46 can be used as a mounting seat, so that the multilayer printed wiring board 47 can be screwed and fixed. .

In addition, since the opposing surfaces 4a, 4a of the composite film 6 that are in contact with the thermosetting prepreg 46 described above are surface-modified so that the contact angle with H ₂ O is 70 degrees or less,
There is an effect that a sufficient bondability of these both 46 and 6 can be secured.

Further, the low melting point fluororesin 5 constituting another layer in addition to the PTFE resin 4 constituting one layer of the composite film 6 is made of PFA, FEP, ETFE, ECTF.
Since it is possible to select from various kinds of low melting point fluororesins such as E and PCTFE, it is possible to obtain various kinds of ultra-thin composite films 6 having a two-layer structure. Therefore, the above-mentioned thermosetting prepreg 46 and unsintered prepreg are used. There is an effect that the manufacturing process of the used laminated plate can be standardized.

In the correspondence between the constitution of the present invention and the above-mentioned embodiments, the base material of the present invention corresponds to the glass cloth base materials 1, 25, 35 and 40 of the embodiments, and the same applies to the metal foil. , Cu foils 23 and 28, the present invention is not limited to the configurations of the above-described embodiments.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a laminated board manufactured by a method for manufacturing a laminated board of the present invention.

FIG. 2 is an explanatory view of a manufacturing apparatus used for manufacturing the composite film for laminated plate of the present invention.

FIG. 3 is a cross-sectional view of the composite film for laminated plate of the present invention.

FIG. 4 is an exploded sectional view showing another embodiment of the method for manufacturing a laminated board.

FIG. 5 is a partial cross-sectional view after completion of secondary molding.

FIG. 6 is a partial cross-sectional view showing a comparative example.

FIG. 7 is an exploded sectional view showing still another embodiment of the method for manufacturing a laminated board.

FIG. 8 is an exploded sectional view showing still another embodiment of the method for manufacturing a laminated board.

FIG. 9 is an exploded sectional view showing still another embodiment of the method for manufacturing a laminated board.

FIG. 10 is an exploded sectional view showing still another embodiment of the method for manufacturing a laminated board.

FIG. 11 is an exploded cross-sectional view showing still another embodiment of the method for manufacturing a laminated board.

FIG. 12 is an exploded cross-sectional view showing still another embodiment of the method for manufacturing a laminated board.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Glass cloth base material 2 ... PTFE resin 3 ... Unsintered prepreg 4 ... PTFE resin 4a ... Opposing surface 5 ... Low melting point fluororesin 6 ... Composite film 23 ... Cu foil 25, 35, 40 ... Glass cloth base material 27 ... Unsintered prepreg 28 ... Cu foil 29 ... Circuit part G, N ... Circuit layer 30 ... Insertion film 37 ... Unsintered prepreg 42 ... Sintered prepreg 46 ... Thermosetting prepreg

Claims (8)

[Claims] 1. A base material is impregnated with a PTFE resin dispersion, which is dried at a low temperature with respect to the melting point of the PTFE resin, and the impregnation and drying are repeated to form a green prepreg having a required resin retention amount. On the other hand, one layer is PTFE
A composite film for a laminated plate having a two-layer structure in which the other layer is made of a resin and a fluororesin having a low melting point with respect to the PTFE resin is formed. After placing the metal foil, PTF
A method for producing a laminated plate, which comprises heating and pressing at a high temperature with respect to the melting point of E resin. 2. A two-layer structure film comprising a PTFE resin dispersion deposited on a plate to form a thin layer, and a fluorine resin dispersion having a low melting point with respect to PTFE resin deposited on the thin layer surface. A composite film for laminated plates formed by peeling from a plate. 3. The low melting point fluororesin dispersion comprises PFA, FEP, ETFE, ECTFE and PC.
The composite film for a laminate according to claim 2, which is one of TFEs made of a fluororesin dispersion. 4. A base material impregnated with a fluororesin dispersion and then dried to form an unsintered prepreg, and a metal foil is disposed on at least one surface of the unsintered prepreg, and the temperature is higher than the melting point of the fluororesin. A plurality of circuit layers for the inner layer and the outer layer having a circuit portion heated and pressed by the above are formed, and one layer is a PTFE resin and the other layer is the P layer between the plurality of circuit layers.
Made of fluororesin with a low melting point for TFE resin 2
A composite film having a layered structure is interposed, one side of the composite film is opposed to the circuit side and the other side is opposed to the circuit side, and the PFA is provided between the composite film one side and the facing member.
Alternatively, a method for producing a laminated plate, in which an FEP interposing film is interposed and heating and pressing are performed at a temperature higher than the melting point of PTFE. 5. A non-sintered prepreg, which is obtained by impregnating a base material with a fluororesin and then drying, between the plurality of circuit films, wherein a plurality of the composite films are provided between the plurality of circuit layers. 4. The method for producing a laminated plate as described in 4. 6. A plurality of the composite films are provided between the plurality of circuit layers, and a sintered prepreg obtained by impregnating a base material with a fluororesin and then drying and sintering is provided between the plurality of composite films. The method for manufacturing a laminated board according to claim 4. 7. A substrate is impregnated with a fluororesin dispersion and then dried to form an unsintered prepreg, and a metal foil is disposed on at least one surface of the unsintered prepreg, and the temperature is higher than the melting point of the fluororesin. A plurality of circuit layers for the inner layer and the outer layer having a circuit portion heated and pressed by the above are formed, and one layer is a PTFE resin and the other layer is the P layer between the plurality of circuit layers.
Made of fluororesin with a low melting point for TFE resin 2
A composite film having a layered structure is interposed, and one side of the composite film is opposed to the circuit side and the other side is opposed to the circuit side for heat fusion, and the surface opposite the circuit side has a contact angle of 70 degrees or less. The surface of the two or more circuit layers is thermoset prepreg which is baked and solidified at a low temperature with respect to the epoxy or polyimide fluororesin, and is lower than the PTFE constituting the two-layer structure composite film. A method for producing a laminated plate, which comprises heating and pressurizing at a low temperature with respect to the melting point of the fluororesin. 8. The low melting point fluororesin is PFA or FE.
1 of P, ETFE, ECTFE and PCTFE
The method for manufacturing a laminated board according to claim 7, wherein two fluororesins are used.