KR20160037070A - Method for manufacturing double-faced metal laminate, method for manufacturing printed circuit board, method for manufacturing multiple layered laminate, and method for manufacturing multiple layered printed circuit board - Google Patents

Abstract

The present invention relates to a manufacturing method of a double-sided metal laminate, a manufacturing method of a printed circuit board, and a manufacturing method of a multilayer laminate, and a manufacturing method of a multilayer printed circuit board. The manufacturing method of a double-sided metal laminate includes the following steps: forming lamination by inserting a first prepreg layer between a first metal foil and a second metal foil; and molding a laminate by heating and pressurizing the laminate after pre-heating the laminate.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a double-sided metal laminates, a method for manufacturing a printed circuit board, a method for manufacturing a multilayer laminate, AND METHOD FOR MANUFACTURING MULTIPLE LAYERED PRINTED CIRCUIT BOARD}

The present disclosure relates to a method of manufacturing a double-sided metal laminate, a method of manufacturing a printed wiring board, a method of manufacturing a multilayer laminate, and a method of manufacturing a multilayer printed wiring board. More particularly, the present invention relates to a method for producing a multilayer printed circuit board widely applicable to various electronic apparatuses such as a computer, a mobile communication telephone, and a video camera, and a method for manufacturing a double-sided metal laminate, a printed wiring board and a multilayer laminate .

2. Description of the Related Art In recent years, electronic components tend to become smaller and more highly integrated, faster, and multi-pinned as electronic components become more sophisticated and denser. Along with this, there is a growing demand for printed wiring boards in terms of high density, small size, light weight, and thinness.

In order to comply with these demands, in general, in addition to reducing the width of wirings and gaps of wirings, the thickness of the insulating layer and wiring layers constituting the printed wiring board is reduced. In addition, conventionally, a multilayer printed wiring board (four-layer board) having four wiring layers and a multilayer printed wiring board (six-layer board) having six wiring layers are widely used. On the other hand, the thickness of the printed wiring board is also reduced by using a multi-layer printed wiring board such as a three-layer board or a five-layer board in which the number of wirings is reduced from those of the multilayer printed wiring board.

Next, a conventional three-layer plate manufacturing method will be described. 3A to 3F are cross-sectional views showing a conventional double-sided metal laminate 711, a printed wiring board 11, a multi-layer laminate board 721, and a method of manufacturing the multilayer printed wiring board 101. FIG. First, as shown in FIG. 3A, a first prepreg layer 311 is disposed between the first metal foil 211 and the second metal foil 221 to form a laminate 611. The first prepreg layer 311 is cured to form the first insulation layer 411 by heating and pressing the laminate 611. As shown in Fig. 3B, the first insulation layer 411, A double-side metal laminate plate 711 having a first metal foil 211 and a second metal foil 221 is obtained. Only the first metal foil 211 among the first metal foil 211 and the second metal foil 221 in the double-sided metal laminate 711 is subjected to the wiring forming process. As a result, a printed wiring board 11 having a second metal foil 221, a first insulating layer 411, and a first wiring 511 is obtained as shown in Fig. 3C. A multilayer laminate 621 is formed as shown in FIG. 3D by laminating a second prepreg layer 321 and a third metal foil 231 on the first wiring 511 of the printed wiring board 11 in this order do. The multilayer laminate 621 is heated and pressed. As a result, the second prepreg layer 321 is cured to form the second insulating layer 421, and as shown in FIG. 3E, the second metal foil 221, the first insulating layer 411, A multilayer laminate 721 is obtained in which the first wiring 511, the second insulating layer 421, and the third metal foil 231 are laminated in this order. A second wiring 521 and a third wiring 531 are formed by subjecting the second metal foil 221 and the third metal foil 231 of the multilayer laminate 721 to a wiring forming process. 3F, a multilayer printed wiring board 101 (three-layer printed wiring board) having three layers of wiring (first wiring 511, second wiring 521, and third wiring 531) ) Is obtained.

However, warpage is likely to occur in the three-layer board. The mechanism of the occurrence of warpage is thought to be as follows.

3B) is generated in the first insulating layer 411 of the double-side metal laminate plate 711 shown in Fig. 3B due to curing shrinkage (arrow 811 in Fig. 3B). The first metal foil 211 in this double-sided metal laminate plate 711 is subjected to wiring forming treatment to form the first wiring 511, whereby the printed wiring board 11 is manufactured. As a result, internal stress is released from the first wiring 511 side of the first insulating layer 411, thereby causing warping in the printed wiring board 11 as shown in Fig. 3C. As a result, the three-layered board obtained by multilayering the printed wiring board 11 is likely to be warped.

As shown in FIG. 3D and FIG. 3E, when the multilayer laminate 721 is obtained by heating and pressing the multilayer laminate 621, the second insulating layer 421 of the multilayer laminate 721 , And an internal stress (arrow 831 in FIG. 3E) due to curing shrinkage occurs. As shown in FIG. 3F, the internal stress is released by performing the wiring forming process. As a result, warpage occurs in the multilayered printed circuit board 101 as shown in Fig. 3F.

One of the methods for suppressing warping in such a three-ply board is disclosed in Patent Document 1. [ In this method, a core substrate having a first copper foil layer on each side of the substrate is used, wiring formation processing is performed on one side of the core substrate to form an inner-layer circuit wiring, To remove the first copper foil layer. And a second copper foil layer for forming an outer layer circuit wiring is laminated on both surfaces of the core substrate via a prepreg layer. And each of the second copper foil layers is subjected to a wiring forming process to form an outer layer circuit wiring. By this method, three layers of copper foil are formed.

Japanese Patent Application Laid-Open No. 2010-056373

In the method for producing a double-sided metal clad laminate of the present disclosure, a laminate is formed by sandwiching a first prepreg layer between a first metal foil and a second metal foil,

After preheating the laminate, the laminate is heated and pressed.

In the manufacturing method of a printed wiring board of the present disclosure, the first wiring is formed by performing a wiring forming process on the first metal foil of the double-sided metal laminate plate manufactured as described above.

Further, in the manufacturing method of the multi-layered laminate of the present disclosure,

A second prepreg layer was laminated on the first surface of the printed wiring board manufactured as described above on which the first wiring was formed,

A multilayer laminate is produced by laminating a third metal foil on the second prepreg layer,

After preheating the multilayer laminate, the multilayer laminate is heated and pressed.

Further, in the manufacturing method of the multilayered printed circuit board of the present disclosure,

The second wiring is formed by performing a wiring forming process on at least one of the second metal foil and the third metal foil of the multilayer laminate produced by the above.

In addition, the manufacturing method of the multi-

A printed wiring board having an insulating layer, a first wiring formed on a first surface of the insulating layer, and a metal layer formed on a second surface opposite to the first surface of the insulating layer,

A second prepreg layer is laminated on the first surface of the insulating layer on which the first wiring is formed,

A multilayer laminate is produced by laminating a third metal foil on the second prepreg layer,

After preheating the multilayer laminate, the multilayer laminate is heated and pressed.

Further, in the manufacturing method of the multilayered printed circuit board of the present disclosure,

The second wiring is formed by performing a wiring forming process on at least one of the metal layer and the third metal foil of the multilayer laminate produced as described above.

1A to 1F are cross-sectional views showing a double-sided metal laminate plate, a printed wiring board, a multilayer laminate plate, and a method of manufacturing a multilayer printed wiring board according to an embodiment of the present invention.
2 is a graph showing the relationship between the temperature and the dimensional change amount of the metal foil and the prepreg layer.
3A to 3F are cross-sectional views showing a conventional double-side metal laminate plate, a printed wiring board, a multilayer laminate, and a method of manufacturing a multilayer printed wiring board.

The method described in Patent Document 1 is basically the same as the method of manufacturing a four-layer board. The three-layer board obtained by this method is a structure in which one wiring layer is removed from the four-layer board. That is, the three-layer board manufactured by the method described in Patent Document 1 has three wiring layers, three insulating layers (two prepreg layers, and one substrate). In the method described in Patent Document 1, since the base material is required, the entire thickness can not be sufficiently reduced.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1A to 1F are sectional views showing a method of manufacturing the double-side metal laminate plate 71, the printed wiring board 1, the multilayer laminate plate 72 and the multilayer printed wiring board 10 according to the embodiment of the present invention to be.

The double-sided metal laminate plate 71 is manufactured by forming a laminate 61 by sandwiching the first prepreg layer 31 between the first metal foil 21 and the second metal foil 22, After preheating the water 61, the laminate 61 is heated and pressed.

In this embodiment, a metal foil and a prepreg layer are prepared as the material of the printed wiring board 1 and the multilayer printed wiring board 10. [ Here, the metal foil is a generic name of the first metal foil 21, the second metal foil 22, and the third metal foil 23. The prepreg layer is a generic name of the first prepreg layer 31 and the second prepreg layer 32.

The coefficient of linear expansion of the metal foil is preferably in the range of 16 ppm / K or more and 20 ppm / K or less. As the metal foil, a copper foil is preferable, and for example, an electrolytic copper foil or a rolled copper foil is used. However, the metal foil may not be a copper foil, and may be, for example, an aluminum foil or a stainless foil. The thickness of the metal foil is preferably within a range of, for example, 0.001 mm or more and 0.070 mm or less.

In the present embodiment, the prepreg layer is a layer composed of a single prepreg or a plurality of prepregs, and is a layer formed by laminating a plurality of prepregs.

The prepreg can be obtained, for example, by impregnating a reinforcing material with a thermosetting resin composition and then heat-drying the thermosetting resin composition if necessary.

As the reinforcing material, it is preferable to use a glass woven fabric. However, the reinforcing material may be a glass nonwoven fabric. The reinforcing material is selected from the group consisting of aramid fibers, PBO (polyparaphenylenebenzobisoxazole) fibers, PBI (polybenzimidazole) fibers, PTFE (polytetrafluoroethylene) fibers, PBZT (polyparaphenylenebenzobisthiazole) A woven fabric made of organic fibers such as wholly aromatic polyester fibers, or a nonwoven fabric. The reinforcing material may be woven or nonwoven fabric made of inorganic fibers other than glass fibers.

The thermosetting resin in the thermosetting resin composition preferably contains an epoxy resin. However, the thermosetting resin may contain a polyimide resin, a phenol resin, a bismaleimide triazine resin, or the like. The thermosetting resin composition may contain an inorganic filler.

The prepreg does not need to have a reinforcement. A prepreg without a reinforcing material is obtained, for example, by molding the thermosetting resin composition into a sheet form and then heating and drying as required.

The thickness of the prepreg is preferably in the range of, for example, 0.013 mm or more and 0.500 mm or less.

The coefficient of linear expansion of the prepreg layer at a temperature lower than the glass transition temperature is preferably in the range of 3 ppm / K to 30 ppm / K, and the coefficient of linear expansion at the glass transition temperature or higher is in the range of 4 ppm / K to 40 ppm / K . The coefficient of linear expansion of the prepreg layer is adjusted by appropriately adjusting the kind of the thermosetting resin in the thermosetting resin composition as the material of the prepreg layer, the kind and amount of the filler in the thermosetting resin composition, the kind of the reinforcing material as the material of the prepreg layer .

The glass transition temperature of the prepreg layer is the glass transition temperature of the prepreg contained in the prepreg layer. The glass transition temperature of the prepreg is measured by thermomechanical analysis (TMA).

Hereinafter, a method of manufacturing the printed wiring board 1 and a method of manufacturing the multilayer printed wiring board 10 in the present embodiment will be described in detail.

First, as shown in Fig. 1A, the first prepreg layer 31 is disposed between the first metal foil 21 and the second metal foil 22 to form a laminate 61. [

Next, after the laminate 61 is preheated, the laminate 61 is heated and pressed.

The heating temperature at the time of preliminary heating of the laminate 61 is within the range of the glass transition temperature of the first prepreg layer 31 of 占 0 占 폚 and the maximum value at the time of heating and press molding of the laminate 61 It is preferable to be lower than the heating temperature. That is, it is preferable that the heating temperature at the time of preliminary heating of the laminate 61 is within a range from 20 占 폚 or less of the glass transition temperature of the first prepreg layer 31 to 20 占 폚 or more of the glass transition temperature. It is preferable that no artificial compressive force is applied to the laminate 61 while the laminate 61 is preliminarily heated. The time for preheating the laminate 61 is preferably in the range of 5 seconds or more and 300 seconds or less.

The glass transition temperature of the first prepreg layer 31 is, for example, in the range of 80 占 폚 to 180 占 폚. In this case, the heating temperature at the time of preliminary heating of the laminate 61 is set to a range of, for example, 60 ° C or more and 200 ° C or less. As described above, the heating temperature for the preliminary heating is set to the temperature corresponding to the glass transition temperature of the first prepreg layer 31.

As a preheating method of the laminate 61, for example, a drying oven is used.

After the laminate 61 is preliminarily heated and the laminate 61 is heated and pressed, the first prepreg layer 31 is thermally cured to form the first insulation layer 41. As a result, a double-sided metal laminate plate 71 having the first metal foil 21, the first insulating layer 41, and the second metal foil 22 is obtained as shown in Fig. 1B. Here, the first insulating layer 41 is on the second metal foil 22. The first metal foil 21 is located on the first insulating layer 41.

It is preferable that the timing of starting the heating and press forming of the laminate 61 is immediately after the preheating of the laminate 61 is completed. In other words, it is preferable to start the heating / press forming of the laminate 61 after the preheating of the laminate 61 is finished and before the temperature of the laminate 61 lowers.

Examples of the method of heating and pressing the laminate 61 include a multi-stage vacuum press, a double belt press, a linear roll, and a molding method using a vacuum laminator.

The maximum heating temperature when heating and pressing the laminate 61 is higher than the heating temperature when the laminate 61 is preheated. The conditions for heating and pressing the laminate 61 are set so that the first prepreg layer 31 is sufficiently thermally cured. For example, it is preferable that the heating time in the heating and press forming is in the range of 80 ° C or higher and 350 ° C or lower, the molding pressure is in the range of 0.5 MPa or higher and 6.0 MPa or lower, Within the following range.

The heating temperature may be changed stepwise while the laminate 61 is heated / pressed. For example, the laminate 61 is molded at a heating temperature within a range of 80 ° C or higher and 180 ° C or lower for 1 minute and then heated at a heating temperature within a range of 180 ° C or higher and 350 ° C or lower for 1 minute or more and 240 minutes or less May be formed.

Next, of the first metal foil 21 and the second metal foil 22 in the double-sided metal laminate plate 71, only the first metal foil 21 is subjected to wiring forming treatment to form the first wiring 51 . The wiring formation processing is processing for forming wiring by, for example, the subtractive method or the additive method. As a result, a printed wiring board 1 having a planar metal layer 2 made of the second metal foil 22, the first insulating layer 41, and the first wiring 51 is obtained. Here, the first insulating layer 41 is on the second metal foil 22 (metal layer 2). The first wiring (51) is on the first insulating layer (41).

When the printed wiring board 1 is used for manufacturing the multilayer printed wiring board 10, the printed wiring board 1 is preferably manufactured by a method including the preheating of the laminate 61 as described above . However, the printed wiring board 1 may be manufactured by a method other than the above. For example, in the case of preheating the multilayer laminate 62 at the time of manufacturing the printed wiring board 1, the laminate 61 may not be preheated.

1D, a second prepreg layer 32 and a third metal foil 23 are laminated in this order on the first wiring 51 of the printed wiring board 1 to form a multilayer laminate ( 62). That is, the second prepreg layer 32 is laminated on the surface (first surface) of the printed wiring board 1 on which the first wiring 51 is formed and the third metal foil 23 ) To form a multilayer laminate 62.

Next, after the multi-layer laminate 62 is preheated, the multi-layer laminate 62 is heated and pressed.

The heating temperature at the time of preliminary heating of the multilayer laminate 62 is at least 50 占 폚 higher than the glass transition temperature of the second prepreg layer 32 and at the same time when the multilayer laminate 62 is heated / It is preferable to be lower than the maximum heating temperature. This heating temperature is, for example, within a range of a temperature higher than the glass transition temperature of the second prepreg layer 32 by 50 占 폚 and a temperature lower than the glass transition temperature of the second prepreg layer 32 by 150 占 폚. The glass transition temperature of the second prepreg layer 32 is, for example, in the range of 80 ° C or higher and 180 ° C or lower. In this case, the heating temperature at the time of preliminary heating of the multilayer laminate 62 is set to, for example, within the range of 130 ° C or higher and 330 ° C or lower. As described above, the heating temperature for the preliminary heating is set to a temperature corresponding to the glass transition temperature of the second prepreg layer 32. While the multi-layer laminate 62 is preheated, it is desirable that no artificial compressive force be applied to the multi-layer laminate 62. [ The time for preliminary heating of the multilayer laminate 62 is preferably in the range of 5 seconds or more and 300 seconds or less.

As a preliminary heating method for the multilayer laminate 62, for example, a drying oven is used.

Next, the multilayer laminate 62 is heated and pressed. As a result, the second prepreg layer 32 is thermally cured to form the second insulating layer 42. As a result, the metal layer 2, the first insulating layer 41, the first wiring 51, the second insulating layer 42, and the third metal foil 23 are formed as shown in Fig. Layer laminate 72 is obtained. Here, the first insulating layer 41 is on the metal layer 2. The first wiring (51) is on the first insulating layer (41). The second insulating layer 42 is on the first wiring 51. The third metal foil 23 is on the second insulating layer 42.

It is preferable that the timing of starting the heating / pressurizing of the multilayer laminate 62 is immediately after the preheating of the multilayer laminate 62 is completed. In other words, it is preferable to start the heating / press forming of the multilayer laminate 62 before the temperature of the multilayer laminate 62 lowers after the preheating of the multilayer laminate 62 is completed.

Examples of the method of heating and pressing the multilayer laminate 62 include a multi-stage vacuum press, a double belt press, a linear roll, and a molding method using a vacuum laminator.

The maximum heating temperature when heating and pressing the multilayer laminate 62 is higher than the heating temperature when the multilayer laminate 62 is preheated. The conditions for heating and pressing the multilayer laminate 62 are set so that the second prepreg is sufficiently thermally cured. For example, when the heating temperature at the time of heating and pressure-forming the multilayer laminate 62 is in the range of 130 占 폚 or more and 350 占 폚 or less and the molding pressure is in the range of 0.5 MPa or more and 6.0 MPa or less, The molding time is within a range of, for example, 1 minute to 240 minutes.

The heating temperature may be changed stepwise while the multi-layer laminate 62 is heated / pressed. For example, the multilayer laminate 62 is formed at a heating temperature within a range of 130 ° C or higher and 230 ° C or lower for 1 minute and then heated at a heating temperature within a range of 180 ° C or higher and 350 ° C or lower for 1 minute or more and 240 minutes or less May be formed.

Next, the metal layer 2 of the multilayer laminate 72 is subjected to a wiring forming process to form the second wiring 52. Next, as shown in Fig. The third metal foil 23 in the multilayer laminate 72 is subjected to a wiring forming process to form the third wiring 53. [ In addition, wiring formation treatment may be performed on only one of the metal layer 2 and the third metal foil 23. The wiring formation processing is processing for forming wiring by, for example, the subtractive method or the additive method. The multilayered printed circuit board including the second wiring 52, the first insulating layer 41, the first wiring 51, the second insulating layer 42, and the third wiring 53, (10) is obtained. Here, the first insulating layer 41 is on the second wiring 52. The first wiring (51) is on the first insulating layer (41). The second insulating layer 42 is on the first wiring 51. The third wiring 53 is on the second insulating layer 42.

In the present embodiment, the printed wiring board 1 and the multilayer printed wiring board 10 in which the warp is reduced can be obtained without increasing the thickness. Means that the means for reducing the warpage of the printed wiring board 1 and the multilayer printed wiring board 10 according to the present embodiment is a printed wiring board 1 and a multilayer printed wiring board 10 Quot;) " does not need to be increased. It does not mean that the thickness dimension of the printed wiring board 1 and the multilayer printed wiring board 10 in the present embodiment is smaller than the thickness dimension of the conventional printed wiring board 1 and the multilayer printed wiring board 10. [

In the present embodiment, it is considered that the printed wiring board 1 and the multilayer printed wiring board 10 with reduced warpage are as follows.

In the present embodiment, as shown in Fig. 1A, when the laminate 61 is preheated and then heated and pressed, first prepreg layer 31 and first metal foil 21 ) And the second metal foil 22 thermally expand, respectively. Thus, the relative positional relationship between the first prepreg layer 31, the first metal foil 21, and the second metal foil 22 is determined. The first prepreg layer 31 is bonded to the first metal foil 21 and the second metal foil 22 and the first prepreg layer 31 is bonded to the first prepreg layer 31, And the first metal foil 21 and the second metal foil 22 expand and contract according to the temperature change. Therefore, in order to examine the mechanism of the occurrence of the warpage of the printed wiring board 1, the first prepreg layer 31, the first metal foil 21 and the second metal foil 22 ) Must be taken into consideration.

With respect to the temperature at the time of preliminary heating, as factors of the dimensional change of the first prepreg layer 31, the first metal foil 21, and the second metal foil 22 generated by the heating and press forming, The dimensional change due to the curing shrinkage of the prepreg layer 31 and the dimensional change of the first metal foil 21, the second metal foil 22, the first prepreg layer 31 and the first insulating layer 41, And expansion and contraction due to the temperature change depending on the temperature.

2 is a graph showing an example of the relationship between the temperature and the dimensional change amount of the metal foil and the prepreg layer. The abscissa of Fig. 2 represents the temperature, and the ordinate represents the dimensional change with reference to 25 占 폚. Tg represents the glass transition temperature of the prepreg layer. In general, the dimensional change of the cured product (insulating layer) of the prepreg layer is almost the same as the dimensional change of the prepreg layer below the glass transition temperature.

2, when the stacked body 61 is preheated from room temperature, the amount of increase in the dimensions of the first metal foil 21 and the second metal foil 22 is larger than the increase in the dimension of the first prepreg layer 31 Big. The first prepreg layer 31 and the first metal foil 21 and the second metal foil 22 adhere to each other by the preliminary heating and their relative positional relationship is fixed.

Considering only the curing shrinkage that occurs when the first insulating layer 41 is formed due to thermal curing of the first prepreg, the thickness of the first insulating layer 41 ) Becomes smaller.

On the other hand, only the expansion and contraction due to the temperature change of the first metal foil 21, the second metal foil 22, the first prepreg layer 31 and the first insulation layer 41, The dimensional changes caused by the following are as follows.

The temperature of the laminate 61 is further increased by heating and pressing the laminate 61 so that the amount of increase in the dimension of the first metal foil 21 and the second metal foil 22 is smaller than the amount of increase in the dimension of the first metal foil 21 and the second metal foil 22, The amount of increase of the dimension of the base 31 is increased. That is, the dimension of the first prepreg layer 31 is larger than the dimensions of the first metal foil 21 and the second metal foil 22.

Subsequently, the first prepreg layer 31 is thermally cured by heating and press forming to form the first insulating layer 41. Thereafter, the first metal foil 21, the second metal foil 22, 1 The first metal foil 21, the second metal foil 22 and the first insulating layer 41 shrink when the insulating layer 41 is cooled to room temperature. As described above, the dimensional change of the first insulating layer 41 is substantially the same as the dimensional change of the first prepreg layer 31 below the glass transition temperature. Therefore, referring to FIG. 2, the first metal foil 21, And the second metal foil 22 is larger than the reduction amount of the dimension of the first insulating layer 41. [ Therefore, at the normal temperature, the dimension of the first insulating layer 41 is larger than the dimension of the first metal foil 21 and the second metal foil 22, and the difference in dimension becomes larger than in the case of heating and press forming.

In this way, considering only the expansion and contraction due to the temperature change, the size of the first insulating layer 41 becomes larger than the dimensions of the first metal foil 21 and the second metal foil 22 by performing the preliminary heating.

Considering only the dimensional change due to the curing shrinkage caused by the thermal curing of the first prepreg, the dimension of the first insulating layer 41 is smaller than the dimension of the first metal foil 21 and the second metal foil 22 Lt; / RTI > However, considering only the dimensional change due to the expansion and contraction due to the temperature change, the dimension of the first insulating layer 41 is larger than the dimensions of the first metal foil 21 and the second metal foil 22. The dimensional difference between the first metal foil 21 and the second metal foil 22 and the first insulating layer 41 is reduced due to the simultaneous two dimensional changes. In addition, the absolute value of the dimensional difference generated when only the dimensional change caused by the shrinkage of the cure is considered is larger than the absolute value of the dimensional difference generated when only the dimensional change due to the expansion and contraction due to the temperature change is considered. However, in the present embodiment, by performing the preheating, the difference in the absolute value of the dimensional difference becomes smaller.

In the double-sided metal laminate plate 71, the first insulating layer 41 is bound by the first metal foil 21 and the second metal foil 22. A difference in dimension does not actually occur between the first metal foil 21 and the second metal foil 22 and the first insulating layer 41 and the first insulating layer 41 The internal stress is generated in the direction in which the first and second electrodes 41 and 41 contract (the direction indicated by the arrow 81 in Fig. 1B). In the present embodiment, the internal stress is smaller than when the preheating is not performed (see Fig. 3B).

The first metal foil 21 of the double-sided metal laminate plate 71 is subjected to the wiring forming treatment to form the first wiring 51 to obtain the printed wiring board 1. [ As a result, the internal stress of the first insulating layer 41 is released, and warping occurs in the printed wiring board 1 as shown in Fig. 1C. This warpage occurs when the laminate 61 is not preheated See Fig. 3C).

2, the dimensions of the first metal foil 21 and the second metal foil 22 and the dimensional difference of the first insulation layer 41 in the case where only expansion and contraction due to the temperature change are considered, ) Is preliminarily heated in the vicinity of the glass transition temperature of the first prepreg layer 31 is particularly large. Therefore, in order to effectively suppress warping of the printed wiring board 1, it is preferable that the heating temperature at the time of preliminary heating of the laminate 61 is in the vicinity of the glass transition temperature of the first prepreg layer 31, It is preferable that the glass transition temperature of the first prepreg layer 31 is within a range of 占 0 占 폚.

2, when the heating temperature at the time of preliminary heating of the laminate 61 is higher than the vicinity of the glass transition temperature of the first prepreg layer 31, the warpage of the printed wiring board 1 Can be further reduced. This is because, when the heating temperature at the time of preliminary heating of the laminate 61 is high, the temperature change at the time of cooling based on the preliminary heating becomes large. Therefore, when only the dimensional change due to the expansion and contraction due to the temperature change is considered This is because the difference in dimension between the first metal foil 21 and the second metal foil 22 and the first prepreg layer 31 generated becomes larger. However, referring to FIG. 2, when the temperature of the first prepreg layer 31 becomes higher than the glass transition temperature, the coefficient of thermal expansion thereof rapidly increases. Thus, if the heating temperature at the time of preliminary heating of the laminate 61 is higher than the vicinity of the glass transition temperature of the first prepreg layer 31, The dimension difference between the second metal foil 22 and the first prepreg layer 31 may be greatly influenced. As a result, the elastic modulus may have a large influence on the warpage of the printed wiring board 1 having a small elastic modulus.

In order to stably control the dimensional changes of the first metal foil 21, the second metal foil 22 and the prepreg layer to suppress the warpage of the printed wiring board 1, The heating temperature is preferably not too high as compared with the glass transition temperature of the first prepreg layer 31. The glass transition temperature of the first prepreg layer 31 is preferably within a range of 占 0 占 폚.

1D, when the multilayer laminate 62 is preliminarily heated and then subjected to heating and pressure molding, first preliminary heating is performed to form the second prepreg layer 32 and the second prepreg layer 32, 3 metal foil 23 and the printed wiring board 1 are thermally expanded. Thus, the relative positional relationship between the second prepreg layer 32, the third metal foil 23, and the printed wiring board 1 is determined. Subsequently, when the multilayer laminate 62 is heated and pressed, the second prepreg layer 32, the third metal foil 23 and the printed wiring board 1 are bonded together, and the second prepreg layer 32, The layer 32, the third metal foil 23, and the printed wiring board 1 expand and contract in accordance with the temperature change, respectively. Therefore, in order to examine the mechanism of the occurrence of the warpage of the multilayered printed circuit board 10, it is preferable that the second prepreg layer 32, the third metal foil 23, the printed wiring board 1, , Each of the dimensional changes must be considered. Particularly, it is considered that the dimensional change of the second prepreg layer 32 having a large elastic modulus and the dimensional change of the printed wiring board 1 dominate the occurrence of warpage of the multilayered printed circuit board 10. [

On the basis of the temperature at the time of preliminary heating, as a factor of the dimensional change of the second prepreg layer 32 and the printed wiring board 1 caused by heating and pressing, the second prepreg layer 32 is thermally cured The dimensions of the third metal foil 23, the second prepreg layer 32, and the printed wiring board 1, which are caused by the curing shrinkage that occurs when the second insulating layer 42 is formed, And expansion and contraction due to the temperature change depending on the temperature. Since the printed wiring board 1 is a composite in which the metal layer 2, the first insulating layer 41 and the first wiring 51 are laminated, It is considered to be dominant over the whole dimensional change.

Therefore, it is assumed that the third metal foil 23, the second prepreg layer 32, and the metal layer 2 are laminated. In this case, the second insulating layer 42 is formed by thermally curing the second prepreg layer 32 in the present embodiment by performing the preliminary heating for the same reason as in the case of manufacturing the printed wiring board 1, The dimensional difference between the third metal foil 23 and the metal layer 2 becomes small. As a result, the internal stress generated in the second insulating layer 42 of the multilayer laminate plate 72 is reduced by preliminary heating. As a result, warping of the multilayered printed circuit board 10 is suppressed.

2, considering the expansion and contraction due to the temperature change, the amount of shrinkage of the metal layer 2 is set to be larger than the shrinkage amount of the second insulation layer 2, Is greater than the shrinkage amount of the layer (42). The difference between the shrinkage amount of the metal layer 2 and the shrinkage amount of the second insulating layer 42 becomes larger as the preheating temperature is higher. This difference in shrinkage amount can offset the curing shrinkage that occurs when the second prepreg layer 32 is thermally cured and the second insulating layer 42 is formed. As a result, warping of the multilayered printed circuit board 10 is suppressed.

The higher the heating temperature at the time of preheating the multilayer laminate 62, the larger the difference between the contraction amount of the metal layer 2 and the second insulating layer 42 due to the expansion and contraction due to the temperature change. As a result, the shrinkage amount of the metal layer 2 can be larger than the shrinkage amount of the second insulating layer 42, even if the shrinkage occurs when the second insulating layer 42 is formed. Thus, even if warpage is generated in the printed wiring board 1, a force is applied to the printed wiring board 1 in order to eliminate warpage. This also suppresses the warpage of the multilayered printed circuit board 10.

In order to suppress warpage of the multilayer printed wiring board 10 by eliminating the warpage of the printed wiring board 1, the heating temperature at the time of preliminary heating of the multilayer laminate 62, as described above, 2 < / RTI > higher than the glass transition temperature of the prepreg layer 32,

The multilayer laminate 62 of the present embodiment is used as the core substrate and the multilayer laminate 62 is further multilayered to form a multilayer printed wiring board having five or more odd wiring layers, . Warpage of the core substrate is suppressed, so that warping of the multilayered printed circuit board having five or more wiring layers can be suppressed.

[Example]

Hereinafter, the present invention will be described in detail with reference to examples.

(Example 1)

First, a prepreg layer (first prepreg layer 31) is formed in the following order.

19 parts by mass of a thermosetting resin, 65 parts by mass of an inorganic filler, 16 parts by mass of a curing agent and 0.02 parts by mass of a curing accelerator are prepared. Further, a woven fabric substrate is prepared. Here, as the thermosetting resin, "EPPN502H" manufactured by Nippon Yakushi Kasei Co., Ltd., which is a polyfunctional epoxy resin, is used. As the inorganic filler, spherical silica "SO-C6" (average particle diameter 2 μm) manufactured by Admatech Co., Ltd. is used. As the curing agent, "MEH7600" manufactured by Meiwa Chemical Industry Co., Ltd., which is a phenolic curing agent, is used. As the curing accelerator, 2-ethyl-4-methylimidazole (manufactured by Shikoku Chemical Industry Co., Ltd.) is used. As the woven fabric substrate, " 1017 cross " (thickness 15 占 퐉) manufactured by Asahi Kasei Corporation, which is a glass cloth, is used.

The thermosetting resin composition, the inorganic filler, the curing agent and the curing accelerator are mixed and diluted with a solvent (methyl ethyl ketone) to prepare a varnish-type thermosetting resin composition.

The thermosetting resin composition is impregnated in the above woven fabric substrate and then heated in the range of not less than 100 ° C. and not more than 200 ° C. for not less than 5 minutes and not more than 15 minutes until the thermosetting resin composition becomes semi- Heat drying (primary heating) in the drying furnace. It is further heated and dried (secondary heating) at 120 DEG C for 2 minutes. As a result, a prepreg having a linear expansion coefficient of 16 ppm / K at a glass transition temperature of 120 占 폚, a glass transition temperature of less than 16 ppm / K, a linear expansion coefficient of 20 ppm / K at a glass transition temperature of more than 20 ppm / K, Layer is obtained. The percentage (resin content) of the thermosetting resin composition in the prepreg layer with respect to the total amount of the prepreg layer was 75 mass%.

Next, the prepreg layer is used to produce the printed wiring board 1 in the following procedure.

The prepreg layer is disposed as the first prepreg layer 31 between the two copper foils (the first metal foil 21 and the second metal foil 22) to obtain a laminate 61 . Here, "3EC-VLP" manufactured by Mitsui Metal Mining Co., Ltd. having a thickness of 12 μm and a coefficient of linear expansion of 18 ppm / K is used as the copper foil. This laminate 61 is preliminarily heated at 120 占 폚, which is the glass transition temperature of the prepreg layer, for 1 minute. Subsequently, while maintaining the temperature of the laminate 61 at 120 占 폚, the laminate 61 is placed on a plate heated at 120 占 폚 and heated and pressed under this condition by a heating and pressing method using a multi-stage vacuum press . In the heating and press forming, the laminate 61 was first molded under the conditions of a heating temperature of 120 占 폚, a pressing force of 4.5 MPa, and a molding time of 1 minute. Subsequently, under the conditions of a heating temperature of 220 占 폚, a pressing force of 4.5 MPa, . Thus, the double-sided metal laminate plate 71 is obtained.

Only the copper foil of the double-sided metal laminate plate 71 is subjected to the wiring forming process by the subtractive method to form the wiring (the first wiring 51). Thus, the printed wiring board 1 is obtained.

Next, the multilayer printed wiring board 10 is manufactured using the printed wiring board 1 in the following order.

The multilayer laminate 62 is obtained by laminating the prepreg layer and the copper foil as the second prepreg layer 32 in this order on the wiring of the printed wiring board 1 in this order. Here, as the copper foil, "3EC-VLP" manufactured by Mitsui Metal Mining Co., Ltd. having a thickness of 12 μm is used. The multilayer laminate 62 is first preheated at 220 占 폚 for 1 minute. Subsequently, while maintaining the temperature of the multilayer laminate 62 at 220 占 폚, the multilayer laminate 62 was placed on a plate heated at 220 占 폚, and in this state, the multilayer laminate 62 was heated and pressurized in a heating and pressing manner using a multi- . In the heating and press forming, the multilayer laminate 62 is molded under the conditions of a heating temperature of 220 占 폚, a pressing force of 4.5 MPa, and a molding time of 160 minutes. Thus, a multilayer laminate 72 is obtained.

(Example 2)

The heating temperature at the time of preliminary heating of the laminate (61) is set at 100 캜. A multilayer laminate was produced under the same conditions as in Example 1 except for the above.

(Example 3)

The heating temperature at the time of preliminary heating of the laminate 61 is set at 140 占 폚. A multilayer laminate was produced under the same conditions as in Example 1 except for the above.

(Example 4)

The heating temperature at the time of preliminary heating of the multilayer laminate 62 is set at 170 占 폚. A multilayer laminate was produced under the same conditions as in Example 1 except for the above.

(Example 5)

The heating temperature at the time of preliminary heating of the laminate 61 is 80 占 폚. A multilayer laminate was produced under the same conditions as in Example 1 except for the above.

(Example 6)

The heating temperature at the time of preliminary heating of the laminate 61 is set at 160 캜. A multilayer laminate was produced under the same conditions as in Example 1 except for the above.

(Example 7)

The heating temperature at the time of preheating the multilayer laminate 62 is set at 150 캜. A multilayer laminate was produced under the same conditions as in Example 1 except for the above.

(Comparative Example)

The multilayer laminate is subjected to heating and pressure molding without preheating the laminate, and heating and pressure molding without preheating the multilayer laminate. A multilayer laminate was produced under the same conditions as in Example 1 except for the above.

(Evaluation of Deflection of Multilayer Printed Wiring Board)

From the multi-layer laminate obtained in each of the Examples and Comparative Examples, a sample having a size of 20 cm x 20 cm as viewed from a plane was cut. All the copper foils on both sides of this sample were removed by etching, and the sample was heated at 200 占 폚 for 1 hour.

Subsequently, the sample is arranged so that the wiring formed at the time of manufacturing the printed wiring board is located above the insulating layer formed at the time of manufacturing the printed wiring board. In this state, the amount of deflection of the sample is measured. The amount of bending is defined as a positive value when the bending occurs in a convex shape above the sample, and is defined as a negative value when bending occurs in a downward convex shape. The results are shown in Table 1. In Table 1, the unit of linear expansion coefficient is ppm / K.

[Table 1]

As apparent from Table 1, in each of the examples, warping of the printed wiring board and the multilayer printed wiring board is suppressed as compared with the comparative example.

Particularly, in Examples 1 to 4, the heating temperature at the time of preliminary heating of the laminate 61 is within the range of the glass transition temperature of the prepreg layer (first prepreg layer 31) ± 20 ° C, , The heating temperature at the time of preheating the multilayer laminate 62 is higher than the glass transition temperature of the prepreg layer (second prepreg layer 32) in the multilayer laminate 62 by 50 ° C or more. As a result, the deflection amount is very small.

In Examples 5 and 6, the heating temperature at the time of preheating the multilayer laminate 62 is higher than the glass transition temperature of the prepreg layer in the multilayer laminate 62 by 50 ° C or more. However, the heating temperature at the time of preliminary heating of the laminate 61 is not within the range of the glass transition temperature of the prepreg layer +/- 20 占 폚. As a result, the bending amounts of Examples 5 and 6 are smaller than those of Comparative Examples, but larger than those of Examples 1 to 4.

In Example 7, the heating temperature at the time of preliminary heating of the laminate 61 is within the range of the glass transition temperature of the prepreg layer ± 20 ° C. However, the heating temperature at the time of preheating the multilayer laminate 62 is not higher than the glass transition temperature of the prepreg layer in the multilayer laminate 62 by 50 deg. C or more. Therefore, the amount of warping of Example 7 is smaller than that of Comparative Example, but larger than that of Examples 1 to 4.

 INDUSTRIAL APPLICABILITY As described above, the present invention can provide a method of manufacturing a multilayered printed circuit board capable of suppressing warping of a multilayered printed circuit board without increasing the thickness of the multilayered printed circuit board.

Further, the present invention can provide a method of manufacturing a double-sided metal laminate with reduced internal stress, a method of manufacturing a printed wiring board with reduced warpage, and a method of manufacturing a multilayer laminate board with reduced internal stress.

1, 11 printed wiring board
10, 101 multilayer printed wiring board
2 metal layer
21, 211 First metal foil
22, 221 2nd metal foil
23, 231 3rd metal foil
31, 311 A first prepreg layer
32, 321 second prepreg layer
41, 411 First insulation layer
42, 421 Second insulating layer
51, 511 first wiring
52, 521 Second Wiring
53, 531 Third Wiring
62, 621 multilayer laminate
71, 711 Double-sided metal laminate
72, 721 multilayer laminate
81, 811, 831 Arrow

Claims (13)

A first prepreg layer is sandwiched between the first metal foil and the second metal foil to form a laminate,
Sided metal clad laminate, preliminarily heating the laminate, and then heating and pressing the laminate. The method according to claim 1,
The heating temperature at the time of preliminary heating of the laminate is in a range from 20 DEG C or less of the glass transition temperature of the first prepreg layer to 20 DEG C or more of the glass transition temperature, Sided metal clad laminate is lower than the maximum heating temperature at the time of molding. The method of claim 2,
The coefficient of linear expansion of the first prepreg layer at a temperature lower than the glass transition temperature is in the range of 3 ppm / K or more and 30 ppm / K or less, and the coefficient of linear expansion at the glass transition temperature or more is 4 ppm / K < / RTI > or less. The method of claim 2,
Wherein the coefficient of linear expansion of the first metal foil and the second metal foil is in a range of 16 ppm / K or more and 20 ppm / K or less. A method for producing a printed wiring board, comprising the steps of: preparing a double-sided metal laminate by the method according to claim 1 or claim 2; A printed wiring board is manufactured by the method described in claim 5,
A second prepreg layer is formed on the first surface of the printed wiring board on which the first wiring is formed,
Layered laminate is produced by laminating a third metal foil on the second prepreg layer,
Wherein the multi-layer laminate is preliminarily heated, and then the multi-layer laminate is heated and pressed. An insulating layer,
A first wiring formed on a first surface of the insulating layer,
A printed wiring board having a metal layer formed on a second surface opposite to the first surface of the insulating layer,
A second prepreg layer is stacked on the first surface of the insulating layer on which the first wiring is formed,
Layer laminate is produced by laminating a third metal foil on the second prepreg layer,
Wherein the multi-layer laminate is preliminarily heated, and then the multi-layer laminate is heated and pressed. The method of claim 6,
Wherein the heating temperature at the time of preliminary heating of the multilayer laminate is at least 50 占 폚 higher than the glass transition temperature of the second prepreg layer in the multilayer laminate and the maximum temperature at which the multilayer laminate is heated / Wherein the heating temperature is lower than the heating temperature. The method of claim 8,
Wherein the heating temperature at the time of preheating the multilayer laminate is 150 DEG C or higher than the glass transition temperature of the second prepreg layer in the multilayer laminate. A multi-layered laminate is produced by the method described in claim 6,
And forming a second wiring by subjecting at least one of the second metal foil and the third metal foil to a wiring forming process. A multi-layer laminate is produced by the method described in claim 7,
Wherein the second wiring is formed by performing a wiring forming process on at least one of the metal layer and the third metal foil. The method of claim 7,
Wherein the heating temperature at the time of preliminary heating of the multilayer laminate is at least 50 占 폚 higher than the glass transition temperature of the second prepreg layer in the multilayer laminate and the maximum temperature at which the multilayer laminate is heated / Wherein the heating temperature is lower than the heating temperature. The method of claim 12,
Wherein the heating temperature at the time of preheating the multilayer laminate is 150 DEG C or higher than the glass transition temperature of the second prepreg layer in the multilayer laminate.

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