KR20210118765A - Method for manufacturing laminated board, method for manufacturing printed wiring board, and laminated board - Google Patents

Abstract

An objective of the present disclosure is to provide a manufacturing method of a laminate (12), which can be used for manufacturing a printed wiring board and which can prevent warpage of the printed wiring board. The manufacturing method of a laminate (12) includes: a lamination process of manufacturing a laminated object (11) by layering a resin sheet (2B) and a metallic foil (33) in this order on a first conductor layer (34) of a core material (14) in which a first conductor layer (34), a first insulating layer (21), and a second conductor layer (38) are layered in this order; and a heating process of heating the laminated object (11) to manufacture a laminate (12) in which the core material (14), a second insulating layer (22) manufactured from the resin sheet (2B), and a third conductor layer (39) manufactured from the metallic foil (33) are layered in this order. The second insulating layer (22) has a resin content higher than a resin content of the first insulating layer (21). In the heating process, the laminated object (11) is heated in a state that the outer surface (3A) of the metallic foil (33) is curved to be convex.

Description

The manufacturing method of a laminated board, the manufacturing method of a printed wiring board, and a laminated board TECHNICAL FIELD

The present disclosure relates to a method for manufacturing a laminate, a method for manufacturing a printed wiring board, and a laminate.

Patent Document 1 discloses a method for manufacturing a multilayer laminate. This manufacturing method comprises disposing a first prepreg layer between the first and second metal foils, forming a first insulating layer by thermosetting the first prepreg layer under pressure, and forming a wiring on the first metal foil. and forming the first conductor wiring by performing The above manufacturing method is a multilayer laminate by laminating a second prepreg layer and a third metal foil in this order on the first conductor wiring, and thermosetting the second prepreg layer under pressure to form a second insulating layer. It further includes obtaining

Japanese Patent Laid-Open No. 2016-129264

According to the inventor's investigation, in the case of patent document 1, if a conductor wiring is produced from each of 2nd and 3rd metal foil, a multilayer printed wiring board (printed wiring board) can be obtained. However, in this case, it may become easy to produce curvature in a printed wiring board.

The object of the present disclosure is a method for manufacturing a laminated board that can be used for manufacturing a printed wiring board and which can make it difficult to cause warpage in a printed wiring board, a method for manufacturing a printed wiring board using this laminated board, and a method for manufacturing a printed wiring board using the laminated board, which can be used to produce a printed wiring board To provide a laminate.

In the method for manufacturing a laminate according to an aspect of the present disclosure, a resin sheet and a metal foil are applied to the first conductor layer of a core material in which a first conductor layer, a first insulating layer, and a second conductor layer are laminated in this order in this order A laminated sheet in which the core material, the second insulating layer made from the resin sheet, and the third conductor layer made from the metal foil are laminated in this order by a lamination process of producing a laminated product and heating the laminated product It includes a heating process to manufacture. The resin content is higher in the second insulating layer than in the first insulating layer. The said heating process WHEREIN: The said laminated body is heated in the state curved so that the outer surface of the said metal foil might become convex.

A method for manufacturing a printed wiring board according to an aspect of the present disclosure includes a wiring forming step of manufacturing a conductor wiring by removing a part of at least one of the second conductor layer and the third conductor layer in the laminate. .

A laminate according to an aspect of the present disclosure includes a core material provided to laminate a first conductor layer, a first insulating layer, and a second conductor layer in this order, a second insulating layer, and a third conductor layer, The second insulating layer and the third conductor layer are overlapped in this order on the first conductor layer of the core material. The resin content is higher in the second insulating layer than in the first insulating layer. The said laminated board has the roll shape wound so that the outer surface of the said 3rd conductor layer might become convex.

1 is a cross-sectional view of a laminate according to an embodiment of the present disclosure.
FIG. 2 is an explanatory diagram of an example of a step of laminating a first conductor layer, a first insulating layer, and a second conductor layer in the embodiment.
Fig. 3A is a cross-sectional view of a core material of a first example according to the embodiment. Fig. 3B is a cross-sectional view of the core material of the second example according to the embodiment.
4 : is explanatory drawing of an example of the process of overlapping a resin sheet and metal foil on the 1st conductor layer in the said embodiment.
5A is a perspective view of a state in which the laminate according to the embodiment is wound. 5B is a cross-sectional view of the laminate.
Fig. 6 is a cross-sectional view of the printed wiring board according to the embodiment.

First, an outline of one embodiment of the present disclosure will be described.

The manufacturing method of the laminated board 12 which concerns on this embodiment is the core material 14 in which the 1st conductor layer 34, the 1st insulating layer 21, and the 2nd conductor layer 38 were laminated|stacked in this order, A lamination step (refer to Figs. 2 to 4) of stacking the resin sheet 2B and the metal foil 33 on the first conductor layer 34 in this order to produce the laminate 11 is included. In this method, by heating the laminate 11 , the core material 14 , the second insulating layer 22 made from the resin sheet 2B, and the third conductor layer 39 made from the metal foil 33 . ) further includes a heating step (see Fig. 1 and Figs. 5A to 5B) for manufacturing the laminated plates 12 laminated in this order. The resin content of the second insulating layer 22 is higher than that of the first insulating layer 21 . A heating process WHEREIN: The laminated body 11 is heated in the state curved so that the outer surface of the metal foil 33 might become convex.

By removing a part of each of the second conductor layer 38 and the third conductor layer 39 in the laminate 12, the first conductor from the second conductor layer 38 and the third conductor layer 39, respectively. The wiring 35 and the second conductor wiring 36 can be manufactured. Thereby, the printed wiring board 13 can be manufactured.

According to this embodiment, it can make it hard to produce curvature in the printed wiring board 13. The reason is assumed to be as follows. However, the present disclosure is not limited by the following reasons.

When the laminate 12 is produced by heating the laminate 11 , a stress in the direction in which the second insulating layer 22 is reduced is likely to occur inside the second insulating layer 22 . This is because the resin content of the second insulating layer 22 is higher than that of the first insulating layer 21, so that when cooled after heating, the second insulating layer 22 tends to shrink more easily than the first insulating layer 21. This is because, when the resin sheet 2B has thermosetting properties, the second insulating layer 22 is more likely to contract due to curing shrinkage due to the curing of the resin sheet 2B. Therefore, if the heating step is performed without bending the laminate 11 , the second conductor layer 38 and the third conductor layer 39 are removed by removing a part of each of the second conductor layer 38 and the third conductor layer 39 . When each conductor wiring is made from the conductor layer 39, the stress in the second insulating layer 22 is released by loosening the restraints applied to the second insulating layer 22, and the second insulating layer 22 ) shrinks, and warpage tends to occur in the printed wiring board.

However, in the present embodiment, as described above, in the heating step, the laminate 11 is curved so that the outer surface 3A of the metal foil 33 is convex. It is easy to bend in the opposite direction to the bending that occurs. Therefore, when the printed wiring board 13 is manufactured from the laminated board 12, the tendency of the curvature which arose at the time of manufacture of the laminated body 11, and the shrinkage|contraction of the 2nd insulating layer 22 at the time of manufacture of the printed wiring board 13. It is thought that the tendency of the curvature which arises is canceled and it becomes difficult to produce curvature in the printed wiring board 13.

Next, with reference to FIGS. 1-6, this embodiment is demonstrated in more detail.

As shown in FIG. 1, the laminated board 12 manufactured in this embodiment has the 2nd conductor layer 38, the 1st insulating layer 21, the 1st conductor layer 34, and the 2nd insulating layer. (22) and the third conductor layer 39 have a structure in which they are stacked in this order. That is, the laminated board 12 includes a core material 14 provided so that the first conductor layer 34 , the first insulating layer 21 , and the second conductor layer 38 are laminated in this order, and the second insulating layer. (22) and a third conductor layer (39), wherein the first conductor layer (34) of the core material (14), the second insulating layer (22) and the third conductor layer (39) are formed in this order are overlapping The laminated board 12 may be curved so that the outer surface of the 3rd conductor layer 39 may become a convex shape. That is, the laminated board 12 may be curved so that it may protrude toward the direction D1 which goes from the 1st insulating layer 21 toward the 2nd insulating layer 22. As shown in FIG. The laminated board 12 may have the roll shape wound so that the outer surface of the 3rd conductor layer 39 may become convex.

The first conductor layer 34 is a layer produced from the first metal foil 31 (refer to FIG. 2 ), and is embedded between the first insulating layer 21 and the second insulating layer 22 . In the example of FIG. 1 , the first conductor layer 34 is a wiring 37 . In addition, the 1st conductor layer 34 may not be the wiring 37, but metal foil may be sufficient as it, for example. When the first conductor layer 34 is the wiring 37, the first conductor layer 34 is formed by, for example, etching a part of the first metal foil 31 laminated on the first insulating layer 21 by etching. formed by removing

The second conductor layer 38 is a layer produced from the second metal foil 32 , and is formed in close contact with the first insulating layer 21 .

The third conductor layer 39 is a layer produced from metal foil (third metal foil) 33 , and is formed in close contact with the second insulating layer 22 .

The first insulating layer 21 is an electrically insulating layer, and is formed by bringing the first resin sheet 2A (see FIG. 2 ) into close contact with the first conductor layer 34 and the second conductor layer 38 . When the first conductor layer 34 is the wiring 37 , the first insulating layer 21 is also in close contact with the second insulating layer 22 .

As the 1st resin sheet 2A, a liquid crystal polymer film, a polyimide film, a prepreg, etc. are mentioned, for example.

The first resin sheet 2A contains, for example, a thermosetting resin. In this case, it is preferable that 2 A of 1st resin sheets are prepreg.

When the first resin sheet 2A is a prepreg, the prepreg impregnates a reinforcing material with a thermosetting resin composition (hereinafter, sometimes referred to as composition (X)), and then heats the composition (X) as needed. It is obtained by drying.

Composition (X) contains a thermosetting resin.

The thermosetting resin may contain, for example, at least one resin selected from the group consisting of an epoxy resin, a phenol resin, a cyanate resin, a melamine resin, and an imide resin. As an epoxy resin, a polyfunctional epoxy resin, a bisphenol-type epoxy resin, a novolak-type epoxy resin, a biphenyl-type epoxy resin, etc. are mentioned, for example.

Composition (X) may further contain fillers.

It is preferable that a filler is an inorganic filler. The inorganic filler may contain, for example, at least one selected from the group consisting of silica, aluminum hydroxide, magnesium hydroxide, calcium carbonate, talc, and alumina.

It is preferable that the ratio of the filler with respect to the composition (X) whole quantity is 30 mass % or more and 80 mass % or less. When the ratio of the filler is 30 mass % or more, the dimensional change before and after an etching process and the dimensional change from after an etching process to after an aging process can be made smaller. Moreover, if the ratio of a filler is 80 mass % or less, a composition (X) can be impregnated into a reinforcing material.

The composition (X) may further contain a curing agent and a curing accelerator.

As a hardening|curing agent, a phenol type hardening|curing agent, a dicyandiamide hardening|curing agent, etc. are mentioned, for example.

Examples of the curing accelerator include imidazoles, phenol compounds, amines, and organic phosphines.

Composition (X) may further contain a solvent. This solvent is used in order to dilute the component in composition (X). Composition (X) containing a solvent is also called a varnish. As a solvent, methyl ethyl ketone, toluene, styrene, methoxypropanol etc. are mentioned, for example.

The prepreg, as described above, contains a reinforcing material. Examples of the reinforcing material include inorganic fibers such as glass cloth, glass paper and glass mat, and organic fibers such as aramid cloth. When a reinforcing material is a glass cloth, a glass woven fabric may be sufficient as a reinforcing material, and a glass nonwoven fabric may be sufficient as it.

Although the thickness of a prepreg is 0.013 mm or more and 0.500 mm or less, for example, it is not limited to this.

The second insulating layer 22 is an electrically insulating layer, and the resin sheet (second resin sheet) 2B (see FIG. 4 ) is in close contact with the first conductor layer 34 and the third conductor layer 39 . is formed by As such a 2nd resin sheet 2B, a polyimide film, a prepreg, etc. are mentioned, for example.

The second resin sheet 2B contains, for example, a thermosetting resin. In this case, it is preferable that the 2nd resin sheet 2B is a prepreg. When the second resin sheet 2B contains a thermosetting resin, cure shrinkage occurs when the second resin sheet 2B is heated, but in this embodiment, as described above, the second resin sheet 2B causes cure shrinkage. Even if it does, it is hard to produce curvature in the printed wiring board 13.

When the 2nd resin sheet 2B is a prepreg, this prepreg is carried out similarly to the case where 2 A of 1st resin sheets are a prepreg, and is formed. That is, this prepreg contains a reinforcing material and a composition (X).

When the composition (X) contains a polyfunctional epoxy resin as a thermosetting resin, a crosslinked structure is formed upon curing of the composition (X), so that the second resin sheet 2B is cured to prepare the second insulating layer 22 When it becomes, cure shrinkage is especially easy to occur. However, in this embodiment, even if the composition (X) contains a polyfunctional epoxy resin, as described above, in the heating step, the laminate 11 is curved so that the outer surface 3A of the metal foil 33 is convex. It can be made difficult to produce the curvature resulting from cure shrinkage of the 2nd resin sheet 2B in the wiring board 13. As shown in FIG.

As described above, the resin content of the second insulating layer 22 is higher than that of the first insulating layer 21 . That is, the 2nd resin sheet 2B is produced so that the resin content rate of the 2nd insulating layer 22 may become higher than the resin content rate of the 1st insulating layer 21 . In this embodiment, even if the resin content rate of the 2nd insulating layer 22 is higher than the resin content rate of the 1st insulating layer 21 in this way, the curvature of the printed wiring board 13 can be made difficult to occur. Although the difference in particular between the resin content rate of the 2nd insulating layer 22 and the resin content rate of the 1st insulating layer 21 is not restrict|limited, For example, The resin content rate of the 2nd insulating layer 22 is 66 mass % or more and 74 mass %. Below, the resin content rate of the 1st insulating layer 21 is 64 mass % or more and 72 mass % or less, and the difference between them is 1 mass % or more and 3 mass % or less.

The material of the 1st metal foil 31, the 2nd metal foil 32, and the 3rd metal foil 33 may be same or different. Each of the 1st metal foil 31, the 2nd metal foil 32, and the 3rd metal foil 33 is copper foil, aluminum foil, or stainless steel foil etc., for example. Although each thickness of the 1st metal foil 31, the 2nd metal foil 32, and the 3rd metal foil 33 is 2 micrometers or more and 70 micrometers or less, for example, it is not limited to this.

The manufacturing method of the laminated board 12 which concerns on this embodiment includes a lamination|stacking process and a heating process.

In the lamination step, a resin sheet and a metal foil are laminated in this order on the first conductor layer of the core material 14 in which the first conductor layer, the first insulating layer, and the second conductor layer are laminated in this order to produce a laminate. do.

The manufacturing method of the laminated board 12 may further include the process of manufacturing the core material 14 (henceforth a core manufacturing process) before a lamination|stacking process. In the core production step, for example, as shown in Fig. 2, first, the first metal foil 31, the first resin sheet 2A, and the second metal foil 32 are laminated in this order to form a first laminate. produce By hot-pressing a 1st laminated body, the 1st metal foil 31, the 1st resin sheet 2A, and the 2nd metal foil 32 are laminated and integrated. Thereby, the 1st conductor layer 34 produced from the 1st metal foil 31, the 1st insulating layer 21 produced from the 1st resin sheet 2A, and the 2nd metal foil 32 produced from The core material 14 in which the 2 conductor layers 38 were laminated|stacked in this order is obtained.

In hot-pressing the first laminate, for example, a double belt press method can be employed. This double belt press method can be implemented with the manufacturing apparatus shown in FIG. This manufacturing apparatus is equipped with the double belt press apparatus 7 .

The double belt press device 7 includes a pair of endless belts 4 , a drum 9 , and a pair of thermo-pressing devices 10 . A pair of endless belts 4 are arrange|positioned up and down so that a 1st laminated body may be pinched|interposed between them. Among the pair of endless belts 4 , one endless belt 4 is hooked between the two drums 9 , and the other endless belt 4 is hooked between the two drums 9 . . A pair of thermo-pressing apparatus 10 is provided so that the endless belts 4 and 4 and the 1st laminated body may be pinched|interposed between them. And the hot-pressing apparatus 10 hot-presses the 1st laminated body via the endless belt 4 . The thermo-pressure device 10 includes, for example, a hydraulic plate. The hydraulic plate is configured to hot press the first laminate through the endless belt 4 by the hydraulic pressure of the heated liquid.

Although the endless belt 4 is not limited, For example, it is made of metal.

Moreover, a pair of drums 9 which oppose up and down rotate so that the core material 14 produced from the 1st laminate may be sent toward the winder 8A. In accordance with this rotation, the pair of endless belts 4 rotate.

In hot-pressing the first laminate, the first metal foil 31 , the first resin sheet 2A, and the second metal foil 32 are continuously supplied to the double belt press apparatus 7 . A first laminate in which the first metal foil 31, the first resin sheet 2A, and the second metal foil 32 are laminated in this order is formed immediately before being fed into the double belt press apparatus 7, The first laminate is hot-pressed by a double belt press method.

By employing the double belt press method, a uniform pressure is applied to the entire pressing surface of the first laminate through a pair of endless belts 4 . Thereby, it becomes difficult to produce a dispersion|variation in the pressure applied to the 1st resin sheet 2A between the 1st metal foil 31 and the 2nd metal foil 32. As shown in FIG.

When hot-pressing the first laminate, for example, the first laminate is heated as it approaches the double belt press device 7 . Next, the first laminate is further heated when passing through the drum 9 , and is hot-pressed through the endless belt 4 while passing through the thermo-pressurizing device 10 . And the hot-pressed first stack is cooled as it passes through the drum ( 9 ) and away from the thermo-pressing device ( 10 ). And the produced core material 14 is wound up in roll shape by the winding machine 8A, and is formed into the 1st winding body 81. As shown in FIG.

Conditions for hot pressing the first laminate include, for example, a heating temperature of 200°C or more and 320°C or less, a pressure of 1 MPa or more and 5 MPa or less, and a heating time of 2 minutes or more and 5 minutes or less. The heating time of the first laminate is the time required for the first laminate to pass through the thermo-pressurizing device 10 . The conditions at the time of hot-pressing a 1st laminated body are not limited to the above.

When the 1st resin sheet 2A contains a thermosetting resin, it is preferable that the 1st insulating layer 21 contains the thermosetting resin by which the 1st insulating layer 21 is not fully hardened|cured in the core material 14 used in a lamination|stacking process. For that purpose, it is preferable that the conditions for hot-pressing the first laminate in the core production step are such that the first resin sheet 2A is not completely cured. In this case, since curing shrinkage of the first insulating layer 21 occurs when the second resin sheet 2B is heated in a state in which the second resin sheet 2B is superposed on the core material 14, the first insulating layer 21 and the second insulating layer ( 22), it becomes easy to relieve|moderate the difference of the dimensional change, Therefore, it becomes difficult to produce especially the curvature of the printed wiring board 13.

In this embodiment, the core material 14 continuously sent out from the double belt press apparatus 7 is wound up in roll shape with the winder 8A, and is formed into the 1st winding body 81. As shown in FIG.

In the core production step, the first conductor layer 34 may be formed as the wiring 37 . In this case, by removing a part of the first conductor layer 34, the first conductor layer 34 can be formed as the wiring 37 (refer to Fig. 3B). In forming the wiring 37 , for example, the core material 14 is drawn out from the first winding 81 and transported, and the first conductor layer 34 is etched to form the wiring 37 . Then, the core material 14 is wound up in roll shape at a position facing the first winding body 81 . As the etching process, for example, a subtractive method can be employed.

In this embodiment, the core material 14 provided with the 1st conductor layer 34 formed as the wiring 37 shown in FIG. 3B is used in the lamination|stacking process. On the other hand, without forming the first conductor layer 34 as the wiring 37, as shown in Fig. 3A, the first conductor layer 34 is a uniform metal layer, and the core material 14 is used in the lamination process. do.

In the lamination step, a resin sheet (second resin sheet) 2B and a metal foil (third metal foil) 33 are stacked in this order on the first conductor layer 34 of the core material 14 to form a laminate (second resin sheet) It is a process of manufacturing the laminated body) 11 (refer FIG. 4).

In the lamination step, it is preferable to hot press the second laminate 11 . In hot-pressing the second laminate 11, for example, a double belt press method can be employed. This double belt press method can be implemented by the manufacturing apparatus shown in FIG. This manufacturing apparatus is equipped with the double belt press apparatus 7 . In this manufacturing apparatus, the core material 14 wound in roll shape is provided in the feeding machine 8B.

The double belt press device 7 includes a pair of endless belts 4 , a drum 9 , and a pair of thermo-pressing devices 10 . A pair of endless belts 4 are arrange|positioned up and down so that the 2nd laminated body 11 may be pinched|interposed between them. Among the pair of endless belts 4 , one endless belt 4 is hooked between the two drums 9 , and the other endless belt 4 is hooked between the two drums 9 . . A pair of thermo-pressurizing apparatus 10 is provided so that the endless belts 4 and 4 and the 2nd laminated body 11 may be pinched|interposed between them. And the hot-pressing apparatus 10 hot-presses the 2nd laminated body 11 via the endless belt 4 interposing. The thermo-pressure device 10 includes, for example, a hydraulic plate. The hydraulic plate is configured to heat press the second laminate 11 through the endless belt 4 by the hydraulic pressure of the heated liquid.

Although the endless belt 4 is not limited, For example, it is made of metal.

Moreover, a pair of drums 9 which oppose up and down rotate so that the 2nd laminated body 11 may be sent toward 8 C of winding machines. In accordance with this rotation, the pair of endless belts 4 rotate.

During the lamination process, the core material 14 , the second resin sheet 2B, and the third metal foil 33 are continuously supplied to the double belt press apparatus 7 . The 2nd laminated body 11 which laminated|stacked the core material 14, the 2nd resin sheet 2B, and the 3rd metal foil 33 in this order is the feeder 8B and the double belt press apparatus 7 It is formed in between, and this 2nd laminated body 11 is hot-pressed by the double belt press method.

By employing the double belt press method for the second lamination process, a uniform pressure is applied to the entire pressurized surface of the second laminate 11 via a pair of endless belts 4 . Thereby, it becomes difficult to produce a dispersion|variation in the pressure applied to the 2nd resin sheet 2B between the 3rd metal foil 33 and the core material 14. As shown in FIG. When the 2nd laminated body 11 is hot-pressed, the 2nd resin sheet 2B and the 3rd metal foil 33 closely_contact|adhere.

When the second laminate 11 is hot-pressed, for example, the second laminate 11 is heated as it approaches the double belt press device 7 . Next, the 2nd laminated body 11 is heated further when passing through the drum 9, and is hot-pressed via the endless belt 4, passing through the thermo-pressing apparatus 10. As shown in FIG. And the hot-pressed second stack 11 is cooled as it passes through the drum 9 and away from the thermo-pressurizing device 10 . And the 2nd laminated body 11 is wound up in roll shape by 8 C of winding machines, and is formed into the 2nd winding body 82. As shown in FIG.

Conditions for hot pressing the second laminate 11 include, for example, a heating temperature of 200° C. or more and 320° C. or less, a pressure of 1 MPa or more and 5 MPa or less, and a heating time of 2 minutes or more and 5 minutes or less. The heating time of the second laminate 11 is a time required for the second laminate 11 to pass through the thermo-pressurizing device 10 . The conditions at the time of hot-pressing the 2nd laminated body 11 are not limited to the above.

In this embodiment, the 2nd laminated body 11 continuously sent out from the double belt press apparatus 7 is wound up in roll shape with the winding machine 8C, and is formed into the 2nd winding body 82 (FIG. 4 and 5A). Such a second laminate 11 is curved such that the outer surface 3A of the third metal foil 33 is convex (refer to Fig. 5B). In other words, the second laminate 11 is curved so as to protrude from the first insulating layer 21 toward the direction D1 toward the second resin sheet 2B. As for the curvature of the second laminate 11, the outer surface of the third metal foil 33 (the surface 3A not in contact with the second resin sheet 2B) faces outward when the second winding body 82 is formed. This is realized by winding up the second laminate 11 with the winder 8C.

The second winding body 82 as shown in FIG. 5A has an inner peripheral surface 83 and an outer peripheral surface 84 . The inner peripheral surface 83 is an inner peripheral surface of a cylinder constituted by the second winding body 82 , and the outer peripheral surface 84 is an outer peripheral surface of the above-described cylinder.

When the 2nd resin sheet 2B has thermosetting property, in the 2nd laminated body 11 obtained by the lamination process, it is preferable that the 2nd resin sheet 2B is not hardened|cured completely. Specifically, it is preferable that the 2nd resin sheet 2B contains the thermosetting resin which is not hardened|cured completely.

In addition, when the 1st resin sheet 2A contains a thermosetting resin, the 1st insulating layer 21 produced from the 1st resin sheet 2A is the 2nd laminated body 11 after the hot press in the lamination process. ), may or may not be completely cured. It is more preferable that the 1st insulating layer 21 is not fully hardened|cured. Specifically, it is preferable that the 1st insulating layer 21 contains the thermosetting resin which is not hardened|cured completely. That is, in the lamination process, it is preferable to heat-press the second laminate 11 under conditions in which the first insulating layer 21 is not completely cured.

When the first insulating layer 21 in the second laminate 11 is not completely cured, for example, when the first insulating layer 21 is completely cured, its glass transition temperature is 280°C or more and 320°C or more. When set to °C or less, it is preferable that the glass transition temperatures of the 1st insulating layer 21 in the 2nd laminated body 11 are 190 degreeC or more and 220 degrees C or less. In addition, the glass transition temperature of the 2nd resin sheet 2B in case the 2nd resin sheet 2B has not hardened|cured completely may be the same as the above.

In the lamination process, when the second laminate 11 is hot-pressed under a condition in which the first insulating layer 21 is not completely cured, it is possible to make the printed wiring board 13 less warp. The reason is assumed to be as follows. At the time of heating in a heating process, the 1st insulating layer 21 and the 2nd resin sheet 2B in the state which curved the 2nd laminated body 11 so that the outer surface 3A of the 3rd metal foil 33 might become convex shape. When cured completely, curing shrinkage also occurs in the first insulating layer 21 , so that stress due to cure shrinkage of the second resin sheet 2B is easily relieved. Therefore, the tendency of the curvature which arises by shrinkage|contraction of the 2nd insulating layer 22 at the time of manufacture of the printed wiring board 13 becomes small, and it is thought that it becomes difficult to produce curvature in the printed wiring board 13. As shown in FIG.

In this embodiment, a heating process is performed after a lamination|stacking process.

The heating step is a step of manufacturing the laminated sheet 12 by heating the second laminate 11 in a state in which the outer surface 3A of the third conductor layer 39 is curved so as to be convex. In this laminated board 12, the 2nd insulating layer 22 produced from the 2nd conductor layer 38, the 1st insulating layer 21, the 1st conductor layer 34, and the 2nd resin sheet 2B. ) and the third conductor layer 39 produced from the third metal foil 33 are laminated in this order.

During the heating process, the thermosetting resin in the second laminate 11 may be cured. For this reason, the heating process in this embodiment is also an after-cure process.

It is preferable that the curvature radii of the curved 2nd laminated body 11 in a heating process are 2.5 mm or more and 500 mm or less. The radius of curvature of the second laminate 11 is the radius of curvature of the outer surface 3A of the third metal foil 33 in the cross section in the thickness direction of the second laminate 11 . This radius of curvature is a preferable condition for the degree of curvature of the second laminate 11 when heating the second laminate 11 in the heating step. If the radius of curvature of the second laminate 11 is within the above range, the laminate 12 having a curved shape such that the outer surface 3A of the third conductor layer 39 is convex can be easily obtained, and the laminated sheet ( In the printed wiring board 13 produced using 12), it becomes difficult to produce curvature.

In the heating step, it is preferable to heat the second laminate 11 as it is in the state of the second winding body 82 . That is, when heating the 2nd laminated body 11 in the state which curved so that the outer surface 3A of the metal foil 33 might become convex shape, it is preferable to make it curved by winding the 2nd laminated body 11 in roll shape. In this case, the second winding body 82 can be heated at once, and the laminated board 12 can be easily imparted with a bending habit of bending the laminated board 12 in the opposite direction to the bending that occurs when the printed wiring board 13 is manufactured. can The second winding body 82 can be heated in a furnace in which the furnace temperature is set to a predetermined temperature suitable for curing the second laminate 11 .

When the second laminate 11 is heated as it is in the state of the second winding 82, the radius of curvature of the outer peripheral surface 84 of the second winding 82 is preferably 2.5 mm or more and 500 mm or less, and the inner peripheral surface 83. It is preferable that the radius of curvature of is 2.5 mm or more and 500 mm or less.

Said "state of the 2nd winding body 82" means that when the 2nd laminated body 11 is heated, the 2nd laminated body 11 is wound and curved in roll shape. However, the second laminate 11 may be heated in a state other than the state of the second winding body 82 as long as it is heated in a state in which the outer surface 3A of the third metal foil 33 is curved to be convex.

It is preferable that the thermosetting resin in the 2nd laminated body 11 is fully hardened by a heating process. Specifically, it is preferable that the first insulating layer 21 and the second resin sheet 2B are completely cured by a heating process. On the other hand, as mentioned above, the 2nd insulating layer 22 is produced from the 2nd resin sheet 2B, and the 3rd conductor layer 39 is produced from the 3rd metal foil 33 by a heating process. Although the heating time of a heating process is 0.5 hour or more and 5.0 hours or less, for example, it is not limited to this. In addition, although the heating temperature of a heating process is 200 degreeC or more and 300 degrees C or less, for example, it is not limited to this.

Although the thickness of the 1st insulating layer 21 is 15 micrometers or more and 50 micrometers or less, for example, it is not limited to this. In addition, although the thickness of the 2nd insulating layer 22 is 15 micrometers or more and 50 micrometers or less, for example, it is not limited to this.

The printed wiring board 13 of this embodiment includes producing a conductor wiring by removing at least one part of the 2nd conductor layer 38 and the 3rd conductor layer 39 in the laminated board 12 .

In the wiring forming step, for example, the second conductor layer 38 and the third conductor layer are removed by removing a part of each of the second conductor layer 38 and the third conductor layer 39 in the laminate 12 . From (39), the first conductor wiring 35 and the second conductor wiring 36 are respectively produced. In the wiring formation process, in order to produce the 1st conductor wiring 35 and the 2nd conductor wiring 36, an etching process is employable.

The printed wiring board 13 is manufactured by removing a part of each of the 2nd conductor layer 38 and the 3rd conductor layer 39 by a wiring formation process. In this printed wiring board 13, it becomes difficult to produce curvature as mentioned above.

In this embodiment, a cutting process is performed after a heating process. This cutting process may be performed between a heating process and a wiring formation process, and may be performed after a wiring formation process. When the cutting process is performed between the heating process and the wiring forming process, the laminated board 12 is cut to a size suitable for manufacture of the printed wiring board 13 . Also, when the cutting process is performed after the wiring forming process, the product of the wiring forming process is cut to a size suitable for the printed wiring board 13 . Since the printed wiring board 13 is less prone to warping, even if the printed wiring board 13 is once stored in the magazine rack, it becomes difficult to fall from the magazine rack. For this reason, it becomes easy to convey the printed wiring board 13 in the state stored in the magazine rack.

As shown in Fig. 6, the printed wiring board 13 includes a first conductor wiring 35, a first insulating layer 21, a first conductor layer 34, a second insulating layer 22, and a second conductor wiring ( 36) has a stacked structure in this order. The first conductor layer 34 is buried between the first insulating layer 21 and the second insulating layer 22 . The first conductor wiring 35 is in close contact with the surface of the first insulating layer 21 . The second conductor wiring 36 is in close contact with the surface of the second insulating layer 22 .

When the first conductor layer 34 is the wiring 37 , the first insulating layer 21 and the second insulating layer 22 are in close contact with each other at portions other than the wiring 37 .

In the above embodiment, a double belt press method is employed in order to produce the second laminate 11 in the lamination step. Instead of the double belt press method, a vacuum press method, a linear pressure roll method, or a vacuum laminator method is employed. You can do it.

In the said embodiment, in the heating process, although the 2nd laminated body 11 was heated as it is the 2nd winding body 82, the 2nd laminated body 11 has, for example, two hot discs each each having a curved surface. You may prepare and heat the 2nd laminated body 11 between the curved surfaces of two hot discs. In this case, the second laminate 11 can be heated while the second laminate 11 is curved by the curved surface.

Example

Hereinafter, the present disclosure will be specifically described by way of Examples.

<Examples and Comparative Examples>

Each Example and Comparative Example was performed using the following materials.

Thermosetting resin (polyfunctional epoxy resin): Nippon Kayaku Co., Ltd. make, EPPN-502H.

Hardening|curing agent (phenolic hardening|curing agent): DIC Corporation make, TD-209060M.

Silica: Made by Admatex Co., Ltd., SC-2050MTX.

Talc: Nippon Talc Co., Ltd. product, D-800.

Aluminum hydroxide: Sumitomo Chemical Co., Ltd. make, CL-303.

Reinforcing material: Asahi Kasei Co., Ltd. make, 1017 cloth.

1st metal foil: Mitsui Metals Mining Co., Ltd. make, 3EC-M3-VLP (copper foil; thickness 9 micrometers, coefficient of linear expansion 16 ppm/K).

2nd metal foil: Mitsui Metals Mining Co., Ltd. make, MT18Ex (copper foil; thickness 3 micrometers, coefficient of linear expansion 16 ppm/K).

3rd metal foil: Mitsui Metals Mining Co., Ltd. make, MT18Ex (copper foil; thickness 3 micrometers, coefficient of linear expansion 16 ppm/K).

[Example 1]

(1) Core manufacturing process

The component shown in the column of "1st resin composition" of Table 1 was mix|blended in a container, and the 1st resin composition which is a varnish was prepared by mixing these.

Next, the prepreg which is a 1st resin sheet was produced by making a reinforcing material impregnate the 1st resin composition so that the resin content rate (resin content) after hardening might be set to 68 mass %, and then, drying. This prepreg was sandwiched between the first and second metal foils to produce a first laminate. Then, this first laminate was hot-pressed by a double belt press method. This double belt press system was implemented by the manufacturing apparatus shown in FIG. When the first laminate was hot-pressed, the pressure was 4.0 MPa, the maximum heating temperature was 300° C., and the heating time was 4 minutes. Here, the maximum heating temperature is the set temperature of the thermo-pressurizing device, and the heating time is the time during which the first laminate passes through the thermo-pressing device. Thereby, the core material provided with the 1st conductor layer produced from the 1st metal foil, the 1st insulating layer produced from the 1st resin sheet (prepreg), and the 2nd conductor layer produced from the 2nd metal foil was obtained.

Next, after winding the core material in roll shape to form a first winding, etching treatment is performed only on the first conductor layer of the core material using an etching solution containing cupric chloride or the like as a main component, whereby the first A conductor layer was formed as wiring. And this core material was wound up in roll shape.

(2) Lamination process

The component shown in the column of "2nd resin composition" of Table 1 was mix|blended in a container, and the 2nd resin composition which is a varnish was prepared by mixing these.

Next, the prepreg which is a 2nd resin sheet was produced by making a reinforcing material impregnate a 2nd resin composition so that the resin content rate (resin content) after hardening might become 70 mass %, and then, drying.

Next, a 2nd laminate is produced by laminating|stacking a 2nd resin sheet and 3rd metal foil in this order on the wiring of a core material, and using the manufacturing apparatus shown in FIG. 4, the 2nd laminated body is double belt press. heat-pressed in a way. When the second laminate was hot-pressed, the pressure was 4.5 MPa, the maximum heating temperature was 300° C., and the heating time was 3 minutes. The conditions of this hot press were set so that the 2nd insulating layer produced from the 2nd resin sheet (prepreg) might not harden|cure completely. Here, the maximum heating temperature is the set temperature of the thermo-pressurizing device, and the heating time is the time during which the second laminate passes through the thermo-pressing device.

(3) heating process

Next, the hot-pressed 2nd laminate was wound up in roll shape, and the 2nd winding body was produced. And by heating the 2nd winding body for 2 hours in the heating furnace whose furnace temperature was set to 200 degreeC, it heated in the state which curved the 2nd laminated body so that the outer surface of metal foil (3rd metal foil) might become convex shape. The conditions of this heat press were set so that the 2nd insulating layer produced from the 2nd resin sheet might harden|cure completely.

Thereby, the 2nd conductor layer, the 1st insulating layer, the wiring which is a 1st conductor layer, the 2nd insulating layer produced from the 2nd resin sheet, and the 3rd conductor layer produced from the 3rd metal foil are in this order. A laminated board having a laminated structure was produced.

(4) wiring forming process

Next, the 2nd conductor layer and the 3rd conductor layer in a laminated board were etched using the etching liquid which has cupric chloride etc. as a main component, and 1st conductor wiring and 2nd conductor wiring were formed. Thereby, the printed wiring board which has this 1st conductor wiring and 2nd conductor wiring was obtained. This printed wiring board WHEREIN: The thickness of the 1st insulating layer which is a hardened|cured material of a 1st resin sheet was 23 micrometers, and the thickness of the 2nd insulating layer which is a hardened|cured material of a 2nd resin sheet was 25 micrometers. In addition, the coefficient of linear expansion of the first insulating layer was 15 ppm/K, and the coefficient of linear expansion of the second insulating layer was 15 ppm/K.

[Example 2]

The maximum heating temperature at the time of hot pressing in the core material production process was 270°C, and the heating time was 3 minutes. The conditions of this hot press were set so that the 1st insulating layer produced from the 1st resin sheet (prepreg) might not harden|cure completely. Other than that, it carried out similarly to Example 1, and obtained the laminated board and the printed wiring board.

[Comparative Example 1]

The heating process WHEREIN: The 2nd laminated body was heated in the state made into the flat shape, without winding up in roll shape. Other than that, it carried out similarly to Example 1, and obtained the laminated board and the printed wiring board.

[Comparative Example 2]

The heating process WHEREIN: The 2nd laminated body was heated in the state made into the flat shape, without winding up in roll shape. Other than that, it carried out similarly to Example 2, and obtained the laminated board and the printed wiring board.

<Evaluation>

[Glass transition temperature of the first insulating layer in the second laminate]

In each Example and Comparative Example, the glass transition temperature (Tg) of the first insulating layer in the second laminate after hot pressing in the lamination step was measured by dynamic viscoelasticity measurement. When measuring this glass transition temperature (Tg), the viscoelastic spectrometer "DMS100" manufactured by Seiko Instruments Co., Ltd. was used. In this measurement, tan δ was measured with a bending modulus under the conditions of a frequency of 10 Hz, a temperature increase rate of 5° C./min, and a temperature range of room temperature to 340° C., and the temperature at which tan δ maximizes was taken as the glass transition temperature (Tg). The results are shown in Table 1.

According to these results, the first insulating layer in the second laminate after heat pressing in the lamination step, that is, in the second laminate before the heating step, is completely cured in Example 1 and Comparative Example 1, , in Example 2 and Comparative Example 2, it can be determined that the second laminate is not completely cured.

[Evaluation of the amount of warpage of a printed wiring board]

In each Example and Comparative Example, a sample having a planar view dimension of 24 cm x 8 cm was cut out from the laminate obtained in the heating step. After removing all the 2nd conductor layer and 3rd conductor layer of this sample by the etching process using the said etching liquid, this sample was heated at 200 degreeC for 1 hour.

Next, the sample was placed on the measuring table so that the second insulating layer was positioned above the first insulating layer. In this state, the amount of warpage of the sample was measured. The amount of deflection is the maximum value of the vertical dimension between the measuring table and the surface opposite to the measuring table in the sample, and when the sample has warp in a convex shape above it, it is defined as a positive value, and warps in a convex shape below. When this occurred, it was defined as a negative value. The results are shown in Table 1.

According to the above results, the resin content of the second insulating layer is higher than that of the first insulating layer, and in the heating step, the second laminate is curved so that the outer surface of the third metal foil is convex, so that the resin content is higher than that of the first insulating layer. It has been confirmed that when the 2nd resin sheet is made into a larger stretched state and heated in that state, curvature can be made difficult to occur in the sample when the 2nd conductor layer and the 3rd conductor layer are removed from the sample. On the other hand, when the heating process was performed in the state which made the 2nd laminated body flat like the comparative example, the curvature became large. As a result, when the second conductor layer and the third conductor layer are removed from the sample, the shrinkage of the second insulating layer is greater than that of the first insulating layer. It can be judged that the relaxation was possible by heating the second laminate in a curved state. Moreover, like Example 2, when the heating process was performed in the state in which the 1st insulating layer in a 2nd laminated product was not fully hardened|cured, curvature was suppressed compared with Example 1. Therefore, it has been confirmed that, in the second laminate obtained in the lamination process, when not only the second insulating sheet but also the first insulating layer contain a thermosetting resin that has not been completely cured, the effect of suppressing curvature is high.

11 laminate
12 Laminate
14 core material
2B resin sheet
21 first insulating layer
22 second insulating layer
2B resin sheet
33 metal foil
34 first conductor layer
38 second conductor layer
39 third conductor layer
3A outside

Claims (8)

a lamination step of stacking a resin sheet and metal foil on the first conductor layer of a core material in which a first conductor layer, a first insulating layer, and a second conductor layer are laminated in this order to produce a laminate;
a heating step of producing a laminate in which the core material, the second insulating layer made from the resin sheet, and the third conductor layer made from the metal foil are laminated in this order by heating the laminate;
The resin content of the second insulating layer is higher than that of the first insulating layer,
In the heating step, the laminate is heated in a curved state so that the outer surface of the metal foil becomes convex,
A method for manufacturing a laminate. The method of claim 1,
The resin sheet contains a thermosetting resin,
A method for manufacturing a laminate. 3. The method according to claim 1 or 2,
The resin sheet is a prepreg,
A method for manufacturing a laminate. 3. The method according to claim 1 or 2,
The core material used in the lamination process contains a thermosetting resin in which the first insulating layer is not completely cured,
A method for manufacturing a laminate. 5. The method of claim 4,
In the lamination process, the laminate is hot-pressed under a condition that the first insulating layer is not completely cured,
A method for manufacturing a laminate. 3. The method according to claim 1 or 2,
In the heating step, the laminate is curved by winding it in a roll shape,
A method for manufacturing a laminate. A wiring forming step of producing a conductor wiring by removing a part of at least one of the second conductor layer and the third conductor layer in the laminated sheet manufactured by the method for manufacturing a laminated sheet according to claim 1 or 2; doing,
A method for manufacturing a printed wiring board. A core material including a first conductor layer, a first insulating layer, and a second conductor layer laminated in this order, a second insulating layer, and a third conductor layer, the first conductor layer of the core material comprising: The second insulating layer and the third conductor layer are overlapped in this order,
The resin content of the second insulating layer is higher than that of the first insulating layer,
a roll shape wound so that the outer surface of the third conductor layer is convex,
laminated plate.

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