JP2020036010A - Method for manufacturing multilayer printed wiring board, resin film and multilayer printed wiring board - Google Patents

Abstract

To provide a resin film capable of manufacturing a multilayer printed wiring board excellent in transmission performance.SOLUTION: A resin film contains a thermosetting compound and an inorganic filler, and has exothermic peak top temperature of 130°C or higher and 200°C or lower in measurement with a differential scanning calorimeter, in which among exothermic peaks having an exothermic peak top temperature of 130°C or higher and 200°C or lower, when a peak temperature of the exothermic peak having the maximum peak height is represented by T°C, a dielectric loss tangent at a frequency of 10 GHz of a cured product of a resin film when being cured at (T+50)°C for 1.5 hours is represented by Df, and a dielectric loss tangent at a frequency of 10 GHz of a cured product of a resin film when being cured at (T+50)°C for 7.5 hours is represented by Df, a ratio of Dfto Dfis 0.9 or more and 1.15 or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a resin film containing a thermosetting compound and an inorganic filler. The present invention also relates to a method for manufacturing a multilayer printed wiring board using the above resin film and a multilayer printed wiring board.

  In a multilayer printed wiring board, a resin film in which a resin material is formed into a film may be used to form an insulating layer for insulating internal layers or to form an insulating layer located on a surface portion. is there. On the surface of the insulating layer, a wiring generally made of metal is laminated.

  The method for manufacturing a multilayer printed wiring board generally includes the following steps (1) to (4). (1) A step of laminating a resin film on the surface of the wiring circuit layer. (2) A step of curing the resin film to form an insulating layer. (3) A step of disposing a wiring circuit layer on the surface of the insulating layer. (4) A step of repeating the above (1) to (3). The wiring circuit layer may be a wiring circuit formed by plating and etching, or a wiring circuit formed by a laser method or an inkjet method.

  As an example of a resin composition that can be used for the resin film, Patent Document 1 below discloses a curable epoxy composition containing an epoxy compound, an active ester compound, and a filler. Patent Document 1 describes that a cured product of the curable epoxy composition (resin film) can be used as an insulating layer of a multilayer printed wiring board or the like.

JP 2015-143302 A

  In a method for manufacturing a multilayer printed wiring board, an insulating layer is formed by heating and curing a resin film. Therefore, when the above-mentioned steps (1) to (3) are repeated, the resin film laminated at an earlier stage is heated more times and for a longer time than the resin film laminated at a later stage. When the resin film (insulating layer) is repeatedly heated, the electrical characteristics (dielectric constant and dielectric loss tangent) of the insulating layer may change. As a result, in the obtained multilayer printed wiring board, a mismatch may occur in the impedance of the transmission line, and the transmission loss may increase. In addition, when the dielectric loss tangent of the insulating layer is increased, the transmission loss may be further increased.

  Note that if the heating temperature in the late stage is moderated in order to suppress the change in the electrical characteristics of the insulating layer formed by being laminated initially, it is difficult to sufficiently cure the resin material laminated in the latter stage. . Slowing the heating temperature in the latter stage and heating for a long time is not preferable because the production time becomes long.

  Furthermore, since the insulating layer is exposed to a high temperature (for example, 260 ° C. or higher) during the reflow process, the electrical characteristics of the insulating layer change, and the transmission performance of the multilayer printed wiring board tends to deteriorate.

  With a conventional resin material, it is difficult to improve the electrical characteristics of both an insulating layer formed by lamination at an early stage and an insulating layer formed by lamination at a later stage.

  An object of the present invention is to provide a resin film capable of manufacturing a multilayer printed wiring board having excellent transmission performance. Another object of the present invention is to provide a multilayer printed wiring board having excellent transmission performance and a method for manufacturing the multilayer printed wiring board.

According to a broad aspect of the present invention, there is provided a method of manufacturing a multilayer printed wiring board having a structure in which insulating layers and wiring circuit layers are alternately stacked on a circuit board, wherein a plurality of insulating layers are formed using a resin film. A method of manufacturing a multilayer printed wiring board for forming a layer, wherein a first insulating layer is formed on a circuit board using a resin film, and a first wiring circuit is formed on the first insulating layer. Forming a layer to form a first insulating-wiring circuit composite layer, and forming a second insulating layer using a resin film on the first insulating-wiring circuit composite layer; Forming a second wiring circuit layer on the second insulating layer to form a second insulating-wiring circuit composite layer; and forming a second insulating-wiring circuit composite layer on the second insulating circuit layer. Forming a third insulating layer using a resin film, and forming a third wiring circuit layer on the third insulating layer. Forming a third insulating-wiring circuit composite layer, forming a fourth insulating layer using a resin film on the third insulating-wiring circuit composite layer, Forming a fourth wiring circuit layer on the fourth insulating layer to form a fourth insulating-wiring circuit composite layer; and forming a resin on the fourth insulating-wiring circuit composite layer. Forming a fifth insulating layer using a film, forming a fifth wiring circuit layer on the fifth insulating layer, and forming a fifth insulating-wiring circuit composite layer; And forming a sixth insulating layer using a resin film on the fifth insulating-wiring circuit composite layer, and forming a sixth wiring circuit layer on the sixth insulating layer. Forming a sixth insulating-wiring circuit composite layer, wherein the resin film contains a thermosetting compound and an inorganic filler, and In the measurement with the differential scanning calorimeter, the peak has an exothermic peak top temperature of 130 ° C or higher and 200 ° C or lower, and the maximum peak height among the exothermic peaks having the exothermic peak top temperature of 130 ° C or higher and 200 ° C or lower. When the peak temperature of the heat generation peak having T is set to T ° C., in each of the steps of forming the first to sixth layers of the insulating-wiring circuit composite layer, the heating temperature for fully curing the resin film is , (T + 30) ℃ least (T + 80) ℃ or less, the transmission loss of the first-layer wiring circuit layer in a multilayer printed wiring board obtained absolute value as IL _1, 5-layer in the multilayer printed wiring board obtained in when the absolute value of the transmission loss of the wiring circuit layer has a IL _5, the ratio of IL ₅ of IL _1, to 0.96 to 1.05, a method for manufacturing a multilayer printed circuit board It is provided.

In a specific aspect of the method for manufacturing a multilayer printed wiring board according to the present invention, the dielectric loss tangent in the frequency 10GHz of first insulating layer in the multilayer printed wiring board obtained as Df _1, in the multilayer printed wiring board obtained the dielectric loss tangent in the frequency 10GHz five-layer insulating layer when the Df _5, the ratio Df ₅ of Df _1, to 0.9 to 1.15.

  In a specific aspect of the method for manufacturing a multilayer printed wiring board according to the present invention, the heating temperature for fully curing the resin film is 190 ° C or more and 200 ° C or less.

  In a specific aspect of the method for manufacturing a multilayer printed wiring board according to the present invention, an insulating layer is formed using a resin film on an insulating-wiring circuit composite layer, and a wiring circuit layer is formed on the insulating layer. By repeating the process, seven or more insulating-wiring circuit composite layers are formed.

  In a specific aspect of the method for manufacturing a multilayer printed wiring board according to the present invention, the thermosetting compound includes an epoxy compound.

According to a wide aspect of the present invention, it includes a thermosetting compound and an inorganic filler, and has an exothermic peak top temperature of 130 ° C. or more and 200 ° C. or less, as measured by a differential scanning calorimeter, and has a temperature of 130 ° C. or more. Among the exothermic peaks having exothermic peak top temperatures of 200 ° C. or less, the peak temperature of the exothermic peak having the maximum peak height is defined as T ° C., and the frequency of the cured product of the resin film cured at (T + 50) ° C. for 1.5 hours. the dielectric loss tangent at 10GHz and _{Df 1.5 h,} the dielectric loss tangent in the frequency 10GHz of the cured product of the resin film was cured for 7.5 hours at (T + 50) ℃ when the _{Df 7.5h, Df 7.5h Wherein} the ratio of Df to _{1.5 h} is 0.9 or more and 1.15 or less.

  In a specific aspect of the resin film according to the present invention, the thermosetting compound includes an epoxy compound.

  The resin film according to the present invention is suitably used for heating at 190 ° C. or more and 200 ° C. or less to fully cure the resin film to form an insulating layer.

  The resin film according to the present invention is suitably used for forming a plurality of insulating layers in a multilayer printed wiring board having a structure in which insulating layers and wiring circuit layers are alternately laminated on a circuit board.

According to a broad aspect of the present invention, a circuit board, an insulating layer formed of a resin film, and a wiring circuit layer are provided, and the insulating layer and the wiring circuit layer are alternately laminated on the circuit board. A first insulating-wiring circuit composite layer composed of a first insulating layer and a first wiring circuit layer on the circuit board, and a second insulating layer And a second insulating-wiring circuit composite layer configured by the second wiring circuit layer and a third insulating-wiring circuit configured by the third insulating layer and the third wiring circuit layer Composed of a composite layer, a fourth insulating-wiring circuit composite layer composed of a fourth insulating layer and a fourth wiring circuit layer, and a fifth insulating layer and a fifth wiring circuit layer Composed of a fifth insulating-wiring circuit composite layer, a sixth insulating layer and a sixth wiring circuit layer At least a layer of an insulating-wiring circuit composite layer, wherein the resin film contains a thermosetting compound and an inorganic filler, and the resin film has a temperature of 130 ° C. or higher, as measured by a differential scanning calorimeter. When the exothermic peak top temperature is below 200 ° C. and the absolute value of the transmission loss of the first wiring circuit layer is IL ₁ and the absolute value of the transmission loss of the fifth wiring circuit layer is IL ₅ , Wherein the ratio of IL ₁ to IL ₅ is 0.96 or more and 1.05 or less.

The method for manufacturing a multilayer printed wiring board according to the present invention is a method for manufacturing a multilayer printed wiring board having a structure in which insulating layers and wiring circuit layers are alternately laminated on a circuit board, using a resin film. And a method of manufacturing a multilayer printed wiring board in which a plurality of insulating layers are formed. According to a method of manufacturing a multilayer printed wiring board according to the present invention, a first insulating layer is formed on a circuit board using a resin film, and a first wiring circuit layer is formed on the first insulating layer. To form a first insulating-wiring circuit composite layer. The method for manufacturing a multilayer printed wiring board according to the present invention includes forming a second insulating layer using a resin film on the first insulating-wiring circuit composite layer, and forming the second insulating layer on the second insulating layer. Forming a second wiring circuit layer, and forming a second insulating-wiring circuit composite layer. The method of manufacturing a multilayer printed wiring board according to the present invention includes forming a third insulating layer using a resin film on the second insulating-wiring circuit composite layer, and forming the third insulating layer on the third insulating layer. Forming a third wiring circuit layer to form a third insulating-wiring circuit composite layer. The method for manufacturing a multilayer printed wiring board according to the present invention includes forming a fourth insulating layer using a resin film on the third insulating-wiring circuit composite layer, and forming the fourth insulating layer on the fourth insulating layer. Forming a fourth wiring circuit layer, and forming a fourth insulating-wiring circuit composite layer. The method for manufacturing a multilayer printed wiring board according to the present invention includes forming a fifth insulating layer using a resin film on a fourth insulating-wiring circuit composite layer, and forming the fifth insulating layer on the fifth insulating layer. Forming a fifth wiring circuit layer, and forming a fifth insulating-wiring circuit composite layer. The method for manufacturing a multilayer printed wiring board according to the present invention includes forming a sixth insulating layer using a resin film on the fifth insulating-wiring circuit composite layer, and forming the sixth insulating layer on the sixth insulating layer. Forming a sixth wiring circuit layer, and forming a sixth insulating-wiring circuit composite layer. In the method for manufacturing a multilayer printed wiring board according to the present invention, the resin film includes a thermosetting compound and an inorganic filler. In the method for manufacturing a multilayer printed wiring board according to the present invention, the resin film has an exothermic peak top temperature of 130 ° C. or more and 200 ° C. or less as measured by a differential scanning calorimeter. In the method for manufacturing a multilayer printed wiring board according to the present invention, the peak temperature of the exothermic peak having the maximum peak height among the exothermic peaks having exothermic peak top temperatures of 130 ° C. or more and 200 ° C. or less is defined as T ° C. In the method for manufacturing a multilayer printed wiring board according to the present invention, in each of the steps of forming the first to sixth layers of the insulating-wiring circuit composite layer, the heating temperature for completely curing the resin film is ( (T + 30) ° C. or higher and (T + 80) ° C. or lower. The method for manufacturing a multilayer printed wiring board according to the present invention, the resulting absolute value and IL ₁ of the transmission loss of the first-layer wiring circuit layer in a multilayer printed wiring board, the fifth layer in the resulting multilayer printed circuit board wiring the absolute value of the transmission loss of the circuit layer is taken as IL _5, the ratio of IL ₅ of IL _1, to 0.96 to 1.05. In the method for manufacturing a multilayer printed wiring board according to the present invention, since the above configuration is provided, a multilayer printed wiring board having excellent transmission performance can be obtained.

The resin film according to the present invention contains a thermosetting compound and an inorganic filler, and has an exothermic peak top temperature of 130 ° C. or more and 200 ° C. or less as measured by a differential scanning calorimeter. In the resin film according to the present invention, the peak temperature of the exothermic peak having the maximum peak height among the exothermic peaks having exothermic peak top temperatures of 130 ° C. or more and 200 ° C. or less is defined as T ° C. In the resin film according to the present invention, the cured product of the resin film cured at (T + 50) ° C. for 1.5 hours has a dielectric loss tangent at a frequency of 10 GHz of Df _1.5h, and is cured at (T + 50) ° C. for 7.5 hours. The dielectric loss tangent of the cured resin film at a frequency of 10 GHz is Df _7.5h . In the resin film according to the present invention, the ratio of Df _7.5h to Df _1.5h is 0.9 or more and 1.15 or less. Since the resin film according to the present invention has the above configuration, it is possible to obtain a multilayer printed wiring board having excellent transmission performance.

The multilayer printed wiring board according to the present invention includes a circuit board, an insulating layer formed of a resin film, and a wiring circuit layer, and the insulating layer and the wiring circuit layer are alternately formed on the circuit board. It has a laminated structure. The multilayer printed wiring board according to the present invention has at least the following first to sixth insulating / wiring circuit composite layers. A first insulating-wiring circuit composite layer including a first insulating layer and a first wiring circuit layer on the circuit board. A second insulating-wiring circuit composite layer including a second insulating layer and a second wiring circuit layer. A third insulating-wiring circuit composite layer including a third insulating layer and a third wiring circuit layer. A fourth insulating-wiring circuit composite layer including a fourth insulating layer and a fourth wiring circuit layer. A fifth insulating-wiring circuit composite layer including a fifth insulating layer and a fifth wiring circuit layer. A sixth insulating-wiring circuit composite layer including a sixth insulating layer and a sixth wiring circuit layer. In the multilayer printed wiring board according to the present invention, the resin film contains a thermosetting compound and an inorganic filler, and the resin film generates heat from 130 ° C. to 200 ° C. in a measurement with a differential scanning calorimeter. Has a peak top temperature. In the multilayer printed wiring board according to the present invention, when the absolute value of the transmission loss of the first wiring circuit layer is IL ₁ and the absolute value of the transmission loss of the fifth wiring circuit layer is IL ₅ , _The ratio of ₁ to IL ₅ is 0.96 or more and 1.05 or less. The multilayer printed wiring board according to the present invention has the above-described configuration, and thus has excellent transmission performance.

FIG. 1 is a cross-sectional view schematically showing a multilayer printed wiring board using a resin film according to one embodiment of the present invention. 2A to 2D are cross-sectional views for explaining a method for obtaining the multilayer printed wiring board shown in FIG. 3A to 3C are cross-sectional views for explaining a method for obtaining the multilayer printed wiring board shown in FIG. 4A to 4F are cross-sectional views illustrating a method for obtaining the multilayer printed wiring board shown in FIG. FIG. 5 is a schematic partial cross-sectional view showing, in an enlarged manner, the vicinity of a signal layer of each of the evaluation substrates manufactured in Examples and Comparative Examples.

  Hereinafter, the present invention will be described in detail.

  The method for manufacturing a multilayer printed wiring board according to the present invention is a method for manufacturing a multilayer printed wiring board having a structure in which insulating layers and wiring circuit layers are alternately laminated on a circuit board, using a resin film. And a method of manufacturing a multilayer printed wiring board in which a plurality of insulating layers are formed.

  According to a method of manufacturing a multilayer printed wiring board according to the present invention, a first insulating layer is formed on a circuit board using a resin film, and a first wiring circuit layer is formed on the first insulating layer. To form a first insulating-wiring circuit composite layer. The method for manufacturing a multilayer printed wiring board according to the present invention includes forming a second insulating layer using a resin film on the first insulating-wiring circuit composite layer, and forming the second insulating layer on the second insulating layer. Forming a second wiring circuit layer, and forming a second insulating-wiring circuit composite layer. The method of manufacturing a multilayer printed wiring board according to the present invention includes forming a third insulating layer using a resin film on the second insulating-wiring circuit composite layer, and forming the third insulating layer on the third insulating layer. Forming a third wiring circuit layer to form a third insulating-wiring circuit composite layer. The method for manufacturing a multilayer printed wiring board according to the present invention includes forming a fourth insulating layer using a resin film on the third insulating-wiring circuit composite layer, and forming the fourth insulating layer on the fourth insulating layer. Forming a fourth wiring circuit layer, and forming a fourth insulating-wiring circuit composite layer. The method for manufacturing a multilayer printed wiring board according to the present invention includes forming a fifth insulating layer using a resin film on a fourth insulating-wiring circuit composite layer, and forming the fifth insulating layer on the fifth insulating layer. Forming a fifth wiring circuit layer, and forming a fifth insulating-wiring circuit composite layer. The method for manufacturing a multilayer printed wiring board according to the present invention includes forming a sixth insulating layer using a resin film on the fifth insulating-wiring circuit composite layer, and forming the sixth insulating layer on the sixth insulating layer. Forming a sixth wiring circuit layer, and forming a sixth insulating-wiring circuit composite layer.

  In the method for manufacturing a multilayer printed wiring board according to the present invention, the resin film includes a thermosetting compound and an inorganic filler.

  In the method for manufacturing a multilayer printed wiring board according to the present invention, the resin film has an exothermic peak top temperature of 130 ° C. or more and 200 ° C. or less as measured by a differential scanning calorimeter.

  In the method for manufacturing a multilayer printed wiring board according to the present invention, the peak temperature of the exothermic peak having the maximum peak height among the exothermic peaks having exothermic peak top temperatures of 130 ° C. or more and 200 ° C. or less is defined as T ° C. In the method for manufacturing a multilayer printed wiring board according to the present invention, in each of the steps of forming the first to sixth layers of the insulating-wiring circuit composite layer, the heating temperature for completely curing the resin film is ( (T + 30) ° C. or higher and (T + 80) ° C. or lower.

The method for manufacturing a multilayer printed wiring board according to the present invention, the resulting absolute value and IL ₁ of the transmission loss of the first-layer wiring circuit layer in a multilayer printed wiring board, the fifth layer in the resulting multilayer printed circuit board wiring the absolute value of the transmission loss of the circuit layer is taken as IL _5, the ratio of IL ₅ of IL _1, to 0.96 to 1.05.

  In the method for manufacturing a multilayer printed wiring board according to the present invention, since the above configuration is provided, a multilayer printed wiring board having excellent transmission performance can be obtained.

  In the method for manufacturing a multilayer printed wiring board according to the present invention, the first wiring circuit layer and the fifth wiring circuit layer are preferably metal layers, and more preferably signal layers.

  In the method for manufacturing a multilayer printed wiring board according to the present invention, the second wiring circuit layer, the third wiring circuit layer, the fourth wiring circuit layer, and the sixth wiring circuit layer each include: , A metal layer, and a power supply layer or a ground layer.

  Therefore, in the method for manufacturing a multilayer printed wiring board according to the present invention, it is preferable that the ratio of the transmission loss in the two signal layers is within the above-described range.

  In the method for manufacturing a multilayer printed wiring board according to the present invention, since the above configuration is provided, it is possible to obtain a multilayer printed wiring board excellent in transmission performance regardless of the position of a wiring circuit layer (for example, a signal layer). .

The resin film according to the present invention contains a thermosetting compound and an inorganic filler, and has an exothermic peak top temperature of 130 ° C. or more and 200 ° C. or less as measured by a differential scanning calorimeter. In the resin film according to the present invention, the peak temperature of the exothermic peak having the maximum peak height among the exothermic peaks having exothermic peak top temperatures of 130 ° C. or more and 200 ° C. or less is defined as T ° C. In the resin film according to the present invention, the cured product of the resin film cured at (T + 50) ° C. for 1.5 hours has a dielectric loss tangent at a frequency of 10 GHz of Df _1.5h, and is cured at (T + 50) ° C. for 7.5 hours. The dielectric loss tangent of the cured resin film at a frequency of 10 GHz is Df _7.5h . In the resin film according to the present invention, the ratio of Df _7.5h to Df _1.5h is 0.9 or more and 1.15 or less.

  Since the resin film according to the present invention has the above configuration, it is possible to obtain a multilayer printed wiring board having excellent transmission performance.

  Since the resin film according to the present invention has the above configuration, a multilayer printed wiring board having excellent transmission performance can be obtained regardless of the position of the wiring circuit layer (for example, the signal layer).

  The resin film according to the present invention is preferably used for forming six or more insulating layers in a multilayer printed wiring board. The resin film according to the present invention can also be used to form five or less insulating layers in a multilayer printed wiring board. Even if the resin film according to the present invention is used to form five or less insulating layers, transmission performance can be improved.

  The multilayer printed wiring board according to the present invention includes a circuit board, an insulating layer formed of a resin film, and a wiring circuit layer, and the insulating layer and the wiring circuit layer are alternately formed on the circuit board. It has a laminated structure. The multilayer printed wiring board according to the present invention has at least the following first to sixth insulating / wiring circuit composite layers. A first insulating-wiring circuit composite layer including a first insulating layer and a first wiring circuit layer on the circuit board. A second insulating-wiring circuit composite layer including a second insulating layer and a second wiring circuit layer. A third insulating-wiring circuit composite layer including a third insulating layer and a third wiring circuit layer. A fourth insulating-wiring circuit composite layer including a fourth insulating layer and a fourth wiring circuit layer. A fifth insulating-wiring circuit composite layer including a fifth insulating layer and a fifth wiring circuit layer. A sixth insulating-wiring circuit composite layer including a sixth insulating layer and a sixth wiring circuit layer.

  In the multilayer printed wiring board according to the present invention, the resin film contains a thermosetting compound and an inorganic filler, and the resin film generates heat from 130 ° C. to 200 ° C. in a measurement with a differential scanning calorimeter. Has a peak top temperature.

In the multilayer printed wiring board according to the present invention, when the absolute value of the transmission loss of the first wiring circuit layer is IL ₁ and the absolute value of the transmission loss of the fifth wiring circuit layer is IL ₅ , _The ratio of ₁ to IL ₅ is 0.96 or more and 1.05 or less.

  The multilayer printed wiring board according to the present invention has the above-described configuration, and thus has excellent transmission performance.

  In the multilayer printed wiring board according to the present invention, the first wiring circuit layer and the fifth wiring circuit layer are preferably metal layers, and more preferably signal layers.

  In the multilayer printed wiring board according to the present invention, the second wiring circuit layer, the third wiring circuit layer, the fourth wiring circuit layer, and the sixth wiring circuit layer are each a metal layer. And preferably a power supply layer or a ground layer.

  Therefore, in the multilayer printed wiring board according to the present invention, it is preferable that the ratio of the transmission loss in the two signal layers is within the above-described range.

  Since the multilayer printed wiring board according to the present invention has the above-described configuration, the transmission performance is excellent regardless of the position of the wiring circuit layer (for example, the signal layer).

  The present inventor has found that a change in dielectric constant and a change in dielectric loss tangent due to heating of a cured product (insulating layer) of a resin film are correlated with a transmission loss of a multilayer printed wiring board. If the present inventors have a specific exothermic peak top temperature and cure a resin film in a specific temperature range, the change in the dielectric constant and the change in the dielectric loss tangent due to the heating of the cured product (insulating layer) of the resin film Was found to be smaller. The present inventor has found that the transmission performance of a multilayer printed wiring board can be improved if the change in the dielectric constant and the change in the dielectric loss tangent due to heating of a cured product (insulating layer) of a resin film can be reduced.

  In a conventional multilayer printed wiring board and a multilayer printed wiring board obtained by a method for manufacturing a conventional multilayer printed wiring board, both an insulating layer formed by being initially laminated and an insulating layer formed by being laminated later are both used. Therefore, it is difficult to improve the electrical characteristics, and as a result, the transmission performance of the multilayer printed wiring board may be reduced. On the other hand, in the multilayer printed wiring board according to the present invention and the multilayer printed wiring board obtained by the method for manufacturing a multilayer printed wiring board according to the present invention, the specific resin film is used. Hard to change and excellent in transmission performance.

  In the measurement of the resin film with a differential scanning calorimeter, the exothermic peak is specifically measured as follows.

  A differential scanning calorimeter (for example, “Q2000” manufactured by TA Instruments) is prepared. Take 8 mg of the resin film in a special aluminum pan and cover with a special jig. This dedicated aluminum pan and an empty aluminum pan (reference) are set in a heating unit, and heated at a rate of 3 ° C./min from −30 ° C. to 250 ° C. in a nitrogen atmosphere, reverse heat flow and non-reverse flow. Observe the heat flow. The exothermic peak observed in the non-reverse heat flow is defined as the exothermic peak of the resin film.

  The resin film has an exothermic peak top temperature of 130 ° C. or more and 200 ° C. or less as measured by a differential scanning calorimeter. If the exothermic peak top temperature is lower than 130 ° C., the storage stability of the resin film may deteriorate. If the heat generation peak top temperature exceeds 200 ° C., the temperature variation of the drying furnace may increase, and it may be difficult to manufacture a multilayer printed wiring board.

  From the viewpoint of further improving the curing reaction of the resin film, the exothermic peak top temperature is preferably 140 ° C. or higher, and more preferably 170 ° C. or lower.

  Among the exothermic peaks having exothermic peak top temperatures of 130 ° C. or more and 200 ° C. or less, the peak temperature of the exothermic peak having the maximum peak height is defined as T ° C. The resin film has at least one exothermic peak top temperature of 130 ° C. or more and 200 ° C. or less as measured by a differential scanning calorimeter. When there is one exothermic peak having an exothermic peak top temperature between 130 ° C. and 200 ° C., the peak temperature T of the exothermic peak having the maximum peak height is the peak temperature of the exothermic peak. When there are a plurality of exothermic peaks having an exothermic peak top temperature of 130 ° C. or more and 200 ° C. or less, the peak temperature T of the exothermic peak having the maximum peak height is the maximum peak height among the exothermic peaks. This is the peak temperature of the exothermic peak.

  Therefore, the peak temperature T of the exothermic peak having the maximum peak height is 130 ° C. or more and 200 ° C. or less. If the peak temperature T is lower than 130 ° C., curing tends to proceed during storage, and the pot life of the resin film may be shortened.

  The peak temperature T is preferably 140 ° C. or higher, preferably 170 ° C. or lower. When the peak temperature T is 170 ° C. or lower, variation in curing of the resin film in the manufacturing process and uncured residue can be suppressed as compared with a case where the peak temperature T exceeds 170 ° C.

  Further, the surface roughness of the surface of the resin film (semi-cured product) after the roughening treatment in the semi-additive process (SAP process) is preferably 200 nm or less. Control of the surface roughness of the surface of the resin film (semi-cured material) after the roughening treatment is greatly affected by the degree of curing of the resin film (semi-cured material) after the roughening treatment. From the viewpoint of controlling the degree of curing of the semi-cured product before the roughening treatment and sufficiently curing in the final cure after the roughening treatment, the peak temperature T is preferably in the above-mentioned temperature range.

  The cured product of the resin film according to the present invention, the multilayer printed wiring board obtained by the method for manufacturing a multilayer printed wiring board according to the present invention, and the dielectric loss tangent at a frequency of 10 GHz of the insulating layer of the multilayer printed wiring board according to the present invention are hollow. Measured at 23 ° C. by the resonance method.

  The dielectric loss tangent at a frequency of 10 GHz of the multilayer printed wiring board obtained by the method for manufacturing a multilayer printed wiring board according to the present invention and the insulating layer of the multilayer printed wiring board according to the present invention was used for the multilayer printed wiring board. The same resin film as the resin film may be cured, and the cured resin film (insulating layer) may be determined.

In the multilayer printed wiring board obtained by the method for manufacturing a multilayer printed wiring board according to the present invention and the multilayer printed wiring board according to the present invention, the dielectric loss tangent of the _first insulating layer at a frequency of 10 GHz is Df1, and the fifth layer is dielectric loss tangent in the frequency 10GHz of the insulating layer and Df _5. When ten or more insulating-wiring circuit composite layers are formed, the dielectric loss tangent of the _tenth insulating layer at a frequency of 10 GHz is Df10. Note that the first insulating layer, the fifth insulating layer, and the tenth insulating layer are preferably insulating layers after the main curing. The insulating layer after the main curing may be pre-cured before the main curing. It is preferable that the insulating layer after the main curing is an insulating layer that is fully cured after the preliminary curing.

The insulating layer used in the manufacturing method and a multilayer printed wiring board of the multilayer printed wiring board according to the present invention, the ratio above Df ₅ of the _{Df 1 (Df 1 / Df 5} ) is 0.9 to 1.15 Preferably, there is. When the ratio (Df ₁ / Df ₅ ) is less than 0.9, the resin component may be excessively volatilized by heating after curing, and as a result, the flexibility of the resin film and the insulating layer may be reduced. The resin film and the insulating layer may be cracked or chipped. If the ratio (Df ₁ / Df ₅ ) is less than 0.9, the gas may accumulate inside due to the lamination of the upper layer, and blisters may be generated. If the above ratio (Df ₁ / Df ₅ ) exceeds 1.15, the transmission performance may be poor.

The insulating layer used in the manufacturing method and a multilayer printed wiring board of the multilayer printed wiring board according to the present invention, the ratio above Df ₅ of the _{Df 1 (Df 1 / Df 5} ) is more preferably 0.95 or more, further It is preferably at least 0.99, particularly preferably at least 1.0, more preferably at most 1.14, even more preferably at most 1.13. When the ratio (Df ₁ / Df ₅ ) is equal to or higher than the lower limit and equal to or lower than the upper limit, the transmission performance can be further improved.

The insulating layer used in the manufacturing method and a multilayer printed wiring board of the multilayer printed wiring board according to the present invention, the ratio above _{Df 10} of the _{Df 1 (Df 1 / Df 10} ) is preferably 0.95 or more, more preferably Is 0.99 or more, more preferably 1.0 or more, preferably 1.25 or less, more preferably 1.2 or less. When the ratio (Df ₁ / Df ₁₀ ) is equal to or higher than the lower limit and equal to or lower than the upper limit, the transmission performance can be further improved.

For enhancing a transmission performance further, it said Df ₁ is preferably 0.008 or less, more preferably 0.005 or less.

The dielectric loss tangent (Df ₁ , Df _5, and Df ₁₀ ) of the _first , _fifth, and _tenth insulating layers is measured using the insulating layers provided on the multilayer printed wiring board. It is difficult. Therefore, Df ₁ , Df ₅ and Df ₁₀ are measured as follows.

A resin film having the same composition as the resin film used when manufacturing the multilayer printed wiring board is prepared. In the manufacturing process of the multilayer printed wiring board, the resin film is cured at the same heating temperature and heating time as the temperature and time when the first insulating layer is heated, and the dielectric property of the obtained cured product (insulating layer) is increased. the tangent measured, and Df _1. In the manufacturing process of the multilayer printed wiring board, the resin film is cured at the same heating temperature and time as the temperature and time at which the fifth insulating layer is heated, and the dielectric property of the obtained cured product (insulating layer) is increased. the tangent measured, and Df _5. In the manufacturing process of the multilayer printed wiring board, the resin film is cured at a heating temperature and a heating time equivalent to the temperature and the time at which the tenth insulating layer is heated, and the dielectric property of the obtained cured product (insulating layer) is increased. the tangent measured, and _{Df 10.} In the manufacturing process of the multilayer printed wiring board, heating is performed for a long time in the order of the first insulating layer> the fifth insulating layer> the tenth insulating layer.

In the resin film according to the present invention, the dielectric loss tangent at a frequency of 10 GHz of a cured product of the resin film cured at (T + 50) ° C. for 1.5 hours is set to Df _1.5h . In the resin film according to the present invention, the dielectric loss tangent at a frequency of 10 GHz of the cured product of the resin film cured at (T + 50) ° C. for 7.5 hours is set to Df _7.5h . In the resin film according to the present invention, the dielectric loss tangent at a frequency of 10 GHz of a cured product of the resin film cured at (T + 50) ° C. for 15 hours is Df _15h .

The resin film according to the present invention, the ratio above _{Df 1.5 h} the _{Df 7.5h (Df 7.5h / Df 1.5h} ) is 0.9 to 1.15. If the above ratio (Df _7.5h / Df _1.5h ) is less than 0.9, the resin component may be excessively volatilized by heating after curing, and as a result, the resin film and the insulating layer Of the resin film and the insulating layer may be cracked or chipped. When the ratio (Df _7.5h / Df _1.5h ) is less than 0.9, the gas is accumulated in the upper layer and blisters may be generated due to the lamination in the upper layer. If the ratio (Df _7.5h / Df _1.5h ) exceeds 1.15, the transmission performance may be poor.

The resin film according to the present invention, the ratio above _{Df 1.5 h} the _{Df 7.5h (Df 7.5h / Df 1.5h} ) is preferably 0.95 or more, more preferably 0.99 or more, further Preferably it is 1.0 or more, preferably 1.14 or less, more preferably 1.13 or less. When the ratio _{(Df 7.5h /} Df _1.5h) is below the lower limit or more and the upper limit, it is possible to further increase the transmission performance.

The resin film according to the present invention, the ratio above _{Df 1.5 h} the _{Df 15h (Df 15h / Df 1.5h} ) is preferably 0.9 or more, more preferably 0.95 or more, more preferably 0. It is 99 or more, particularly preferably 1.0 or more, preferably 1.25 or less, and more preferably 1.2 or less. When the ratio (Df _15h / Df _1.5h ) is equal to or higher than the lower limit and equal to or lower than the upper limit, the transmission performance can be further improved.

From the viewpoint of further improving the transmission performance, the Df _7.5h is preferably 0.008 or less, more preferably 0.005 or less.

In the resin film according to the present invention, the dielectric loss tangent at a frequency of 10 GHz of a cured product of the resin film cured at (T + 30) ° C. or more and (T + 80) ° C. or less for 1.5 hours is Df ′ _{1.5 h} . In the resin film according to the present invention, the dielectric loss tangent at a frequency of 10 GHz of a cured product of the resin film cured at (T + 30) ° C. or higher and (T + 80) ° C. or lower for 7.5 hours is Df ′ _7.5h . In the resin film according to the present invention, the dielectric loss tangent at a frequency of 10 GHz of a cured product of the resin film cured at (T + 30) ° C. or higher and (T + 80) ° C. or lower for 15 hours is Df ′ _15h .

The resin film according to the present invention, the ratio of _{1.5 h} 'above Df of _{7.5 h'} above _{Df (Df '7.5h / Df'} 1.5h) is preferably 1.01 or more, more preferably 1. 02 or more, more preferably 1.03 or more, preferably 1.15 or less, more preferably 1.14 or less, and still more preferably 1.13 or less. When the ratio _{(Df '7.5h / Df' 1.5h} ) is below the lower limit or more and the upper limit, it is possible to further increase the transmission performance.

The ratio of _{1.5 h} 'above Df of _{7.5 h'} above _{Df (Df '7.5h / Df'} 1.5h) is lower than the lower limit and the upper limit or less, (T + 30) ℃ least (T + 80) ℃ This means that the ratio satisfies the lower limit or more and the upper limit or less in a temperature range of half or more of the following. In the entire temperature range of (T + 30) ° C. or more and (T + 80) ° C. or less, it is particularly preferable that the above ratio satisfies the above lower limit and the above upper limit.

  The transmission loss of the multilayer printed wiring board obtained by the method for manufacturing a multilayer printed wiring board according to the present invention, and the transmission loss of the wiring circuit layer of the multilayer printed wiring board according to the present invention are in a range of 100 MHz to 40 GHz using a network analyzer. Is measured. The multilayer printed wiring board obtained by the method for manufacturing a multilayer printed wiring board according to the present invention, and the transmission loss of the wiring circuit layer of the multilayer printed wiring board according to the present invention preferably satisfy the following ratio at least at 38 GHz. . In a wiring circuit layer (for example, a signal layer) where transmission loss is measured, it is preferable that the wiring circuit layer be provided with an extraction electrode so that only the transmission loss in the wiring circuit layer can be measured.

In the multilayer printed wiring board according to the multilayer printed wiring board and the present invention obtained by the production method of the multilayer printed wiring board according to the present invention, the absolute value of the transmission loss of the first wiring circuit layer and IL _1, 5-layer the absolute value of the transmission loss of the wiring circuit layer and IL _5. Further, when ten or more insulating-wiring circuit composite layers are formed, the transmission loss of the tenth insulating layer wiring circuit layer (the tenth wiring circuit layer is preferably a signal layer). to the absolute value and _{IL 10.}

The manufacturing method and a multilayer printed wiring board of the multilayer printed wiring board according to the present invention, the ratio above IL ₅ of the _{IL 1 (IL 1 / IL 5} ) is 0.96 to 1.05. When the ratio (IL ₁ / IL ₅ ) is less than 0.96, the resin component may be excessively volatilized by heating after curing, and as a result, the flexibility of the resin film and the insulating layer is reduced. However, cracking or chipping of the resin film and the insulating layer may occur. If the above ratio (IL ₁ / IL ₅ ) is less than 0.96, gas may accumulate inside and blisters may occur due to the lamination of the upper layer. When the ratio (IL ₁ / IL ₅ ) exceeds 1.05, the transmission performance of the multilayer printed wiring board may be poor.

The manufacturing method and a multilayer printed wiring board of the multilayer printed wiring board according to the present invention, the ratio above IL ₅ of the _{IL 1 (IL 1 / IL 5} ) is preferably 1.03 or less, more preferably 1.01 or less It is. When the ratio (IL ₁ / IL ₅ ) is equal to or less than the upper limit, the transmission performance of the multilayer printed wiring board can be further improved.

The manufacturing method and a multilayer printed wiring board of the multilayer printed wiring board according to the present invention, the ratio above _{IL 10} of the _{IL 1 (IL 1 / IL 10} ) is preferably 1.03 or less, more preferably 1.01 or less It is. When the ratio (IL ₁ / IL ₁₀ ) is equal to or less than the upper limit, the transmission performance of the multilayer printed wiring board can be further improved.

From the viewpoint of further improving the transmission performance, the IL ₁ is preferably 0.2 dB / mm or less, more preferably 0.15 dB / mm or less. Although the measurement result of the transmission loss is a negative value, since the IL ₁ is the absolute value of the transmission loss of the first wiring circuit layer as described above, it is represented by a value of 0 or more.

  The resin film according to the present invention is suitably used as a method for manufacturing a multilayer printed wiring board according to the present invention and a resin film used for the multilayer printed wiring board.

  The resin film is preferably a B-stage film.

(Multilayer printed wiring board and method of manufacturing multilayer printed wiring board)
Hereinafter, the present invention will be clarified by describing specific embodiments and examples of the present invention with reference to the drawings.

  FIG. 1 is a cross-sectional view schematically showing a multilayer printed wiring board using a resin film according to one embodiment of the present invention.

  The multilayer printed wiring board 1 includes a substrate 11 and a wiring circuit layer 12. The multilayer printed wiring board 1 includes a first insulating layer 13, a first wiring circuit layer 14, a second insulating layer 15, a second wiring circuit layer 16, and a third insulating layer. Layer 17, third wiring circuit layer 18, fourth insulating layer 19, fourth wiring circuit layer 20, fifth insulating layer 21, and fifth wiring circuit layer 22 And a sixth insulating layer 23 and a sixth wiring circuit layer 24. The multilayer printed wiring board 1 includes a solder resist film 31. A circuit board is constituted by the board 11 and the wiring circuit layer 12. The first insulating layer 13 and the first wiring circuit layer 14 constitute a first insulating-wiring circuit composite layer. The second insulating layer 15 and the second wiring circuit layer 16 form a second insulating-wiring circuit composite layer. The third insulating layer 17 and the third wiring circuit layer 18 constitute a third insulating-wiring circuit composite layer. The fourth insulating layer 19 and the fourth wiring circuit layer 20 constitute a fourth insulating-wiring circuit composite layer. The fifth insulating layer 21 and the fifth wiring circuit layer 22 constitute a fifth insulating-wiring circuit composite layer. The sixth insulating layer 23 and the sixth wiring circuit layer 24 constitute a sixth insulating-wiring circuit composite layer.

  The substrate 11 has a hole 11a. The hole 11a is a through hole. The substrate 11 is an insulating substrate.

  The wiring circuit layers 12, 14, 16, 18, 20, 22, and 24 are metal layers. The wiring circuit layer 12 is a power supply layer. The wiring circuit layers 14 and 24 are signal layers. The wiring circuit layers 16, 18, 20, 22 are power supply layers or ground layers.

  The solder resist film 31 forms the outermost layer.

  The wiring circuit layer 12 is arranged on the surface of the substrate 11. Further, the wiring circuit layers 12 are partially arranged on the surfaces on both sides of the substrate 11. The wiring circuit layer 12 is also arranged in the hole 11 a of the substrate 11. The portions of the wiring circuit layer 12 located on the surfaces on both sides (the lower side is not shown) are electrically connected by the portions of the wiring circuit layer 12 arranged in the holes 11a. The hole 11a of the substrate 11 is also called a via hole.

  The insulating layer 13 is laminated on the surface of the wiring circuit layer 12. The insulating layer 13 has a hole opened so that the surface of the wiring circuit layer 12 is partially exposed. The holes are also called via holes.

  The wiring circuit layer 14 is disposed on the surface of the insulating layer 13. The insulating layer 13 and the wiring circuit layer 14 constitute a first insulating / wiring circuit composite layer. The wiring circuit layer 14 is partially disposed on the surface of the insulating layer 13 opposite to the wiring circuit layer 12 side. The wiring circuit layer 14 is also arranged in the hole of the insulating layer 13. The surface of the wiring circuit layer 12 and the surface of the wiring circuit layer 14 are connected by the wiring circuit layer 14 disposed in the hole. The wiring circuit layer 12 and the wiring circuit layer 14 are electrically connected.

  An insulating layer 15 is laminated on the surface of the wiring circuit layer 14. The insulating layer 15 has a hole that is opened so that the surface of the wiring circuit layer 14 is partially exposed.

  The wiring circuit layer 16 is arranged on the surface of the insulating layer 15. The insulating layer 15 and the wiring circuit layer 16 constitute a second insulating-wiring circuit composite layer. The wiring circuit layer 16 is partially disposed on the surface of the insulating layer 15 opposite to the wiring circuit layer 14 side. The wiring circuit layer 16 is also arranged in the hole of the insulating layer 15. The surface of the wiring circuit layer 14 and the surface of the wiring circuit layer 16 are connected by the wiring circuit layer 16 disposed in the hole. The wiring circuit layer 14 and the wiring circuit layer 16 are electrically connected.

  An insulating layer 17 is laminated on the surface of the wiring circuit layer 16. The insulating layer 17 has a hole that is opened so that the surface of the wiring circuit layer 16 is partially exposed.

  The wiring circuit layer 18 is disposed on the surface of the insulating layer 17. The insulating layer 17 and the wiring circuit layer 18 form a third insulating-wiring circuit composite layer. The wiring circuit layer 18 is partially arranged on the surface of the insulating layer 17 opposite to the wiring circuit layer 16 side. The wiring circuit layer 18 is also arranged in the hole of the insulating layer 17. The surface of the wiring circuit layer 16 and the surface of the wiring circuit layer 18 are connected by the wiring circuit layer 18 disposed in the hole. The wiring circuit layer 16 and the wiring circuit layer 18 are electrically connected.

  Similarly, fourth to sixth insulating / wiring circuit composite layers are formed.

  In the multilayer printed wiring board 1, the first to sixth insulating-wiring circuit composite layers are formed, but the seventh and subsequent insulating-wiring circuit composite layers may be further formed.

  Further, the circuit board itself may have an insulating-wiring circuit composite layer of the insulating layer and the wiring circuit layer. The circuit board before forming the insulating layer using the specific resin film may be a circuit board having an insulating-wiring circuit composite layer of the insulating layer and the wiring circuit layer. The first insulating-wiring circuit composite layer formed by the resin film may be formed so as to be in contact with the insulating-wiring circuit composite layer on the circuit board. In the present invention, the first insulating-wiring circuit composite layer can be formed using a specific resin film. Using a specific resin film, an insulating-wiring circuit composite layer formed first is defined as a first insulating-wiring circuit composite layer.

  In the printed wiring board, an insulating-wiring circuit composite layer may be formed on both sides of the substrate 11.

  Next, with reference to FIGS. 2A to 2D, 3A to 3C, and 4A to 4F, a method for obtaining the multilayer printed wiring board 1 shown in FIG. 1 will be described. This will be specifically described.

  First, a circuit board on which the wiring circuit layer 12 is disposed on the surface of the board 11 is prepared (FIG. 2A).

  After laminating a resin film on the surface of the wiring circuit layer 12 of the circuit board, curing is advanced by heating to form an insulating layer 13A (FIG. 2B).

  Next, the insulating layer 13A is irradiated with a laser or the like to obtain an insulating layer 13B having holes (FIG. 2C). Examples of the laser include a UV laser, a carbon dioxide laser, an excimer laser, and the like.

  Next, the inside of the hole of the insulating layer 13B is desmeared to obtain the insulating layer 13 in which the inside of the hole is desmeared (FIG. 2D). The inside of the hole is cleaned by the desmear treatment, and the smear is removed. When performing the desmear treatment, it is preferable to roughen the surface of the insulating layer 13B in order to increase the roughness of the surface of the insulating layer 13B. It is preferable that the surface of the insulating layer 13 is roughened. It is preferable that the surface of the insulating layer 13B is roughened and the inside of the hole is cleaned.

  It is preferable to use the same processing liquid for the desmear treatment and the roughening treatment for increasing the roughness of the surface of the insulating layer, and the desmear treatment and the roughening treatment for increasing the roughness of the surface of the insulating layer are preferable. Is preferably performed simultaneously.

  After the desmear process, the surface (land portion, surface to be roughened) of the wiring circuit layer 12 exposed from the opening of the hole may be roughened. Thereby, the wiring circuit layer 12 whose surface has been roughened can be obtained. The desmear process for cleaning the inside of the hole and the roughening process for roughening the surface of the wiring circuit layer 12 may be performed as separate steps. By the roughening treatment after the desmearing treatment, the roughness of the roughened surface of the wiring circuit layer 12 increases. As a result, the contact area of the contact interface between the surface of the wiring circuit layer 12 and the surface of the wiring circuit layer 14 increases. Accordingly, the reliability of conduction between the wiring circuit layer 12 and the wiring circuit layer 14 against thermal shock is increased. For example, in the obtained multilayer printed wiring board 1, cracks are less likely to occur at the contact interface between the wiring circuit layers 12 and 14.

  Next, the surface of the insulating layer 13 is preferably subjected to electroless plating. Thereby, conductivity is imparted to the surface of the insulating layer 13 and it becomes easy to form the wiring circuit layer 14 on the surface of the insulating layer 13 by electrolytic plating or the like.

  Next, a dry film resist is laminated on the surface of the insulating layer 13 to form a resist pattern 51 (FIG. 3A). However, the resist pattern 51 need not always be formed. By forming the resist pattern 51, by performing electroplating or the like on a portion not covered by the resist pattern 51, a conductor layer (wiring circuit layer) can be selectively formed on the surface of the insulating layer 13.

  Next, the wiring circuit layer 14 is formed on the surface of the insulating layer 13 and in the hole of the insulating layer 13 by performing electroplating or the like (FIG. 3B). The wiring circuit layer 12 and the wiring circuit layer 14 are electrically connected by connecting the surface of the wiring circuit layer 12 that has been roughened after the desmear processing and the surface of the wiring circuit layer 14.

  Next, the resist pattern 51 is removed by peeling it off with an alkaline aqueous solution containing sodium hydroxide or the like (FIG. 3C). Next, the electroless copper plating layer formed at the time of forming the wiring circuit layer 14 is removed with an acidic etching solution (for example, “SAC process” manufactured by JCU). Thus, a first insulating-wiring circuit composite layer composed of the first insulating layer 13 and the first wiring circuit layer 14 is formed. When the first insulating-wiring circuit composite layer is formed, the resin film is heated at a heating temperature of (T + 30) ° C. or more and (T + 80) ° C. or less in order to completely cure the resin film. The main curing of the resin film may be performed at the time of forming the insulating layer 13A, or may be performed after forming the wiring circuit layer 14 on the insulating layer 13.

  Next, after a resin film is laminated on the surface of the first insulating-wiring circuit composite layer, curing is advanced by heating to form an insulating layer 15A (FIG. 4A).

  Next, the insulating layer 15A is irradiated with a laser or the like to obtain an insulating layer 15B having holes (FIG. 4B).

  Next, the inside of the hole of the insulating layer 15B is desmeared to obtain the insulating layer 15 in which the inside of the hole is desmeared (FIG. 4C). The inside of the hole is cleaned by the desmear treatment, and the smear is removed. When performing the desmear treatment, it is preferable to roughen the surface of the insulating layer 15B in order to increase the roughness of the surface of the insulating layer 15B.

  It is preferable to use the same processing liquid for the desmear treatment and the roughening treatment for increasing the roughness of the surface of the insulating layer, and the desmear treatment and the roughening treatment for increasing the roughness of the surface of the insulating layer are preferable. Is preferably performed simultaneously.

  After the desmear process, the surface (land portion, surface to be roughened) of the wiring circuit layer 14 exposed from the opening of the hole may be roughened. Thereby, the wiring circuit layer 14 whose surface is roughened can be obtained.

  Next, the surface of the insulating layer 15 is preferably subjected to electroless plating. Thereby, conductivity is imparted to the surface of the insulating layer 15 and it becomes easy to form the wiring circuit layer 16 on the surface of the insulating layer 15 by electrolytic plating or the like.

  Next, a dry film resist is laminated on the surface of the insulating layer 15 to form a resist pattern 52 (FIG. 4D).

  Next, the wiring circuit layer 16 is formed on the surface of the insulating layer 15 and in the hole of the insulating layer 15 by performing electroplating or the like (FIG. 4E). By connecting the surface of the wiring circuit layer 14 that has been roughened after the desmearing process and the surface of the wiring circuit layer 16, the wiring circuit layer 14 and the wiring circuit layer 16 are conducted.

  Next, the resist pattern 52 is removed by peeling it off with an alkaline aqueous solution containing sodium hydroxide or the like (FIG. 4F). In this way, a second insulating-wiring circuit composite layer composed of the second insulating layer 15 and the second wiring circuit layer 16 is formed. When the second insulating-wiring circuit composite layer is formed, the resin film is heated at a heating temperature of (T + 30) ° C. or more and (T + 80) ° C. or less in order to fully cure the resin film. The main curing of the resin film may be performed at the time of forming the insulating layer 15A, or may be performed after forming the wiring circuit layer 16 on the insulating layer 15.

By repeating the above steps, the third and subsequent insulating-wiring circuit composite layers are formed. Thus, the multilayer printed wiring board 1 can be obtained. In the method of manufacturing the multilayer printed wiring board 1, when forming the second insulating layer, the first insulating layer is exposed to a hardening environment for forming the second insulating layer. When forming the third insulating layer, each of the first insulating layer and the second insulating layer is exposed to a hardening environment for forming the third insulating layer. When forming the fourth insulating layer, each of the first insulating layer, the second insulating layer, and the third insulating layer is a hardened environment for forming the fourth insulating layer. Exposed to When the fifth insulating layer is formed, each of the first insulating layer, the second insulating layer, the third insulating layer, and the fourth insulating layer becomes the fifth insulating layer. Exposed to a hardening environment to form When the sixth insulating layer is formed, each of the first insulating layer, the second insulating layer, the third insulating layer, the fourth insulating layer, and the fifth insulating layer And a hardening environment for forming a sixth insulating layer. The first insulating layer is exposed to a curing environment by the number of times of the number of insulating layers to be formed. The second insulating layer is exposed to a curing environment by the number of times of the number of insulating layers to be formed minus one. The third insulating layer is exposed to the curing environment by the number of times equal to the number of insulating layers to be formed-2. The fourth insulating layer is exposed to a hardened environment by the number of times equal to the number of insulating layers to be formed-3. The fifth insulating layer is exposed to a hardened environment by the number of times equal to the number of insulating layers to be formed-4. The sixth insulating layer is exposed to the curing environment by the number of times equal to the number of insulating layers to be formed minus five. The n-th insulating layer is exposed to a curing environment by the number of insulating layers to be formed-(n-1) times. By setting the ratio of IL ₁ to IL ₅ to be 0.96 or more and 1.05 or less, multilayer printed wiring board 1 having excellent transmission performance can be obtained.

  Like the above-described method for manufacturing a printed wiring board, the method for manufacturing a multilayer printed wiring board according to the present invention includes forming a first insulating layer on a circuit board using a resin film, and forming the first insulating layer on the circuit board. Forming a first wiring circuit layer on the insulating layer, and forming a first insulating-wiring circuit composite layer.

  The resin film for forming the first insulating layer is laminated on wiring (circuit) arranged on the surface of the circuit board. The resin film is in contact with a wiring circuit layer (metal layer) portion on the circuit board and a portion where the wiring circuit layer (metal layer) is not formed.

  The method for manufacturing a multilayer printed wiring board according to the present invention includes forming a second insulating layer using a resin film on the first insulating-wiring circuit composite layer, and forming the second insulating layer on the second insulating layer. Forming a second wiring circuit layer, and forming a second insulating-wiring circuit composite layer.

  The method of manufacturing a multilayer printed wiring board according to the present invention includes forming a third insulating layer using a resin film on the second insulating-wiring circuit composite layer, and forming the third insulating layer on the third insulating layer. Forming a third wiring circuit layer to form a third insulating-wiring circuit composite layer.

  The method for manufacturing a multilayer printed wiring board according to the present invention includes forming a fourth insulating layer using a resin film on the third insulating-wiring circuit composite layer, and forming the fourth insulating layer on the fourth insulating layer. Forming a fourth wiring circuit layer, and forming a fourth insulating-wiring circuit composite layer.

  The method for manufacturing a multilayer printed wiring board according to the present invention includes forming a fifth insulating layer using a resin film on a fourth insulating-wiring circuit composite layer, and forming the fifth insulating layer on the fifth insulating layer. Forming a fifth wiring circuit layer, and forming a fifth insulating-wiring circuit composite layer.

  The method for manufacturing a multilayer printed wiring board according to the present invention includes forming a sixth insulating layer using a resin film on the fifth insulating-wiring circuit composite layer, and forming the sixth insulating layer on the sixth insulating layer. Forming a sixth wiring circuit layer, and forming a sixth insulating-wiring circuit composite layer.

  In the present invention, the number of laminated insulating-wiring circuit composite layers of the multilayer printed wiring board is not limited to six. The number of laminated insulating-wiring circuit composite layers may be six, six or more, or seven or more.

  When the number of laminated insulating-wiring circuit composite layers in the multilayer printed wiring board is 7 or more, the n-th insulating layer (n is an integer of 7 or more) is (n-1) th layer. Forming an n-th insulating layer using a resin film on the insulating-wiring circuit composite layer of the eye, and forming an n-th wiring circuit layer on the n-th insulating layer; can do.

  The number of layers of the insulating-wiring circuit composite layer (that is, n) is preferably 7 or more. That is, in the method for manufacturing a multilayer printed wiring board according to the present invention, the steps of forming an insulating layer using a resin film on the insulating-wiring circuit composite layer and forming the wiring circuit layer on the insulating layer are repeated. Thus, it is preferable to form seven or more insulating-wiring circuit composite layers.

  The number of layers (that is, n) of the insulating-wiring circuit composite layer is preferably 7 or more, more preferably 8 or more, preferably 20 or less, and more preferably 15 or less. When the number of the insulating-wiring circuit composite layers (that is, n) is equal to or more than the lower limit and equal to or less than the upper limit, the transmission performance can be further improved.

  In the method for manufacturing a multilayer printed wiring board according to the present invention, after forming an m-th (m is an integer of 1 or more) insulating layer (insulating layer forming step), and on the m-th insulating layer, Before forming the m-th wiring circuit layer (wiring circuit layer forming step), it is preferable to provide a via hole forming step and a desmear processing step in this order. Before or after the desmearing step, a swelling step may be performed, or a roughening step may be performed. The desmearing process may also serve as a roughening process. The swelling step and the roughening step may be performed before the via hole forming step, or may be performed after the via hole forming step. Hereinafter, the insulating layer forming step, the swelling step, the roughening step, the via hole forming step, the desmearing step, the wiring circuit layer forming step, and the main curing step will be specifically described.

<Insulating layer forming step>
The insulating layer is formed by curing a resin film. The insulating layer when the wiring circuit layer is formed can be obtained by accelerating the curing of the resin film. The above-mentioned curing may be preliminary curing or full curing. The above-mentioned curing includes pre-curing which can be further cured. From the viewpoint of suppressing the deterioration of the insulating layer, the above-mentioned curing is preferably preliminary curing. The insulating layer may be a pre-cured product layer of a resin film or a cured product layer of a resin film. The insulating layer is preferably a pre-cured layer of a resin film. In the case where the above-mentioned curing is preliminary curing in the above-described insulating layer forming step, it is preferable to perform a main curing step described later.

  The curing of the resin film is performed by heating.

  In the insulating layer forming step, when pre-curing the resin film, the heating temperature of the resin film is preferably 90 ° C or higher, more preferably 100 ° C or higher, preferably 190 ° C or lower, more preferably 180 ° C or lower. It is. When the heating temperature is equal to or higher than the lower limit and equal to or lower than the upper limit, rapid volatilization of a solvent or a liquid component due to heating can be suppressed.

  When the resin film is pre-cured in the insulating layer forming step, the heating time of the resin film is preferably 0.5 hours or more, more preferably 1 hour or more, preferably 2 hours or less, more preferably 1 hour or less. .75 hours or less. When the heating time is equal to or greater than the lower limit and equal to or less than the upper limit, the amount of resin to be etched in the roughening treatment step can be controlled, and the surface roughness can be reduced. Transmission performance can be improved.

  In the case where the resin film is completely cured in the insulating layer forming step, the heating temperature of the resin film is (T + 30) ° C or more and (T + 80) ° C or less. By setting the heating temperature of the resin film when the resin film is fully cured in the above range, it is possible to suppress a decrease in the electrical characteristics of the insulating layer and to improve the transmission performance of the obtained multilayer printed wiring board. .

  In the case where the resin film is fully cured in the insulating layer forming step, the heating temperature of the resin film is preferably 180 ° C. or higher, more preferably 185 ° C. or higher, further more preferably 190 ° C. or higher, and preferably 210 ° C. or lower. , More preferably at most 205 ° C, even more preferably at most 200 ° C. When the resin film is fully cured, the heating temperature of the resin film is preferably (T + 40) ° C. or higher, and more preferably (T + 60) ° C. or lower. When the heating temperature is equal to or higher than the lower limit and equal to or lower than the upper limit, a decrease in the electrical characteristics of the insulating layer can be more effectively suppressed, and the transmission performance of the obtained multilayer printed wiring board can be further improved. In particular, the resin film according to the present invention is suitably used for heating at 190 ° C. or more and 200 ° C. or less to fully cure the resin film to form an insulating layer.

  In the case where the resin film is completely cured in the insulating layer forming step, the heating time of the resin film is preferably 0.5 hours or more, more preferably 1 hour or more, preferably 2 hours or less, more preferably 1 hour or less. .75 hours or less. When the heating time is equal to or greater than the lower limit and equal to or less than the upper limit, a decrease in electrical characteristics of the insulating layer can be suppressed, and the transmission performance of the obtained multilayer printed wiring board can be increased.

  The curing of the resin film may be performed in a nitrogen environment, or may be performed in an air environment.

  The wiring circuit layer is preferably a wiring circuit formed by plating and etching. The method for forming the wiring circuit layer will be described later.

<Swelling process>
The method for manufacturing a multilayer printed wiring board according to the present invention preferably includes a step of swelling the insulating layer (swelling step). By performing the above-mentioned swelling treatment, a swelling-treated insulating layer can be obtained. By performing the swelling treatment step, the efficiency of the roughening treatment in the roughening treatment step described later is increased. In addition, even when performing the above-mentioned roughening process, the above-mentioned swelling process does not necessarily need to be performed. In the swelling step, a conventionally known swelling method can be employed.

  Examples of the swelling treatment include a method of treating an insulating layer (a cured product (precured product) of a resin film) with a swelling liquid such as an aqueous solution of a compound containing ethylene glycol or the like as a main component or an organic solvent dispersion. .

  The swelling liquid generally contains an alkali as a pH adjuster or the like. The swelling liquid preferably contains sodium hydroxide.

  Specifically, the swelling treatment is performed by treating the insulating layer at a temperature of 30 ° C. to 85 ° C. for 1 minute to 30 minutes using a swelling liquid containing, for example, a 40% by weight aqueous solution of ethylene glycol. The temperature of the swelling treatment is preferably 50 ° C. or more and 85 ° C. or less. If the temperature of the swelling treatment is too low, the swelling treatment requires a long time, and the adhesive strength between the insulating layer and the wiring circuit layer tends to decrease.

<Roughening process>
The method for manufacturing a multilayer printed wiring board according to the present invention preferably includes a step of performing a roughening treatment (roughening treatment step) on the insulating layer. By performing the above roughening treatment, a roughened insulating layer can be obtained. When the swelling process is performed, the roughening process is performed on the swelled insulating layer. By performing the roughening treatment step, small irregularities can be formed on the surface of the insulating layer (the cured product (precured product) of the resin film). In the roughening treatment step, a conventionally known roughening treatment method can be adopted.

  The above-mentioned roughening treatment is performed by using a roughening solution in which water or an organic solvent is added to a chemical oxidizing agent such as a manganese compound, a chromium compound or a persulfate compound to form an insulating layer (a cured product (precured product) of a resin film). And the like.

  Examples of the manganese compound include potassium permanganate and sodium permanganate. Examples of the chromium compound include potassium bichromate and anhydrous potassium chromate. Examples of the above persulfate compound include sodium persulfate, potassium persulfate, and ammonium persulfate.

  The roughening solution generally contains an alkali as a pH adjuster or the like. The above roughening liquid preferably contains sodium hydroxide.

  The temperature of the above roughening treatment is preferably 40 ° C. or more and 85 ° C. or less. The time for the roughening treatment is preferably 5 minutes or more and 45 minutes or less.

<Via hole forming process>
The method for manufacturing a multilayer printed wiring board according to the present invention preferably includes a step of forming a via hole in the insulating layer (a step of forming a via hole). When the method for manufacturing a multilayer printed wiring board according to the present invention includes the swelling step and the roughening step, the method is preferably performed after the roughening step. By performing the via hole forming step, the wiring circuit layer forming step, and the like, an insulating layer in which a via hole is formed can be obtained, and the layers can be electrically connected. In the via hole forming step, a conventionally known via hole forming method can be employed.

  The via hole is preferably formed by irradiating a laser.

Examples of the laser include a CO ₂ laser and the like.

From the viewpoint of workability, the laser is preferably a CO ₂ laser.

  The diameter of the via hole formed is not particularly limited, but is preferably 60 μm or more, and more preferably 80 μm or less.

<Desmear treatment process>
The method for manufacturing a multilayer printed wiring board according to the present invention preferably includes a step (desmear processing step) of removing smear inside the via hole by desmear processing after the via hole forming step. By performing the desmear treatment, an insulating layer subjected to the desmear treatment can be obtained. By performing the desmear treatment, it is possible to effectively remove smear, which is a resin residue derived from the resin component formed in the via hole forming step.

  As the desmear treatment, the insulating layer (cured product (precured product) of the resin film) is treated with a desmear treatment solution in which water or an organic solvent is added to a chemical oxidizing agent such as a manganese compound, a chromium compound or a persulfate compound. There is a method of processing.

  The desmear treatment liquid generally contains an alkali. The desmear treatment liquid preferably contains sodium hydroxide.

  The desmearing step may also serve as the roughening step.

  It is preferable that the temperature of the desmear treatment is 60 ° C. or more and 100 ° C. or less. The desmearing time is preferably 5 minutes or more and 45 minutes or less.

<Wiring circuit layer forming step>
The formation of the wiring circuit layer is preferably performed by an electroless plating step, an electrolytic plating step, and an etching step. By the electroless plating step, the inside of the via hole can be plated, and the layers can be electrically connected. A wiring circuit (wiring circuit layer) can be favorably formed by the electrolytic plating step and the etching step.

  The electroless plating step is preferably an electroless copper plating step.

  In the electroless copper plating step, a conventionally known electroless copper plating method can be employed.

  As the chemical copper solution used in the electroless copper plating process, Atotech Japan's "Basic Print Gant MSK-DK", Atotech Japan's "Copper Print Gant MSK", Atotech Japan's "Stabilizer Print Gant MSK", And a mixed solution of "Reducer Cu" manufactured by Atotech Japan.

  The electrolytic plating step is preferably an electrolytic copper plating step.

  For the electrolytic copper plating step, a conventionally known electrolytic copper plating method can be adopted.

  Examples of the electrolytic copper plating method include a subtractive method such as a panel plating method and a pattern plating method, and a semi-additive method.

  Examples of the aqueous solution of copper sulfate used in the electrolytic copper plating step include “copper sulfate pentahydrate” manufactured by Wako Pure Chemical Industries, “sulfuric acid” manufactured by Wako Pure Chemical Industries, and “Basic Leveler Caparaside HL” manufactured by Atotech Japan. And a mixed solution of "Correcting agent Capalaside GS" manufactured by Atotech Japan.

  In the etching step, a conventionally known etching method can be adopted.

  Examples of the etchant used in the above etching step include an acidic etchant containing 150 g / L of sodium persulfate.

<Main curing step>
In the method for manufacturing a multilayer printed wiring board according to the present invention, when the resin film is preliminarily cured in the insulating layer forming step, after the wiring circuit layer is formed on the insulating layer, Process. In the case where the resin film has been fully cured in the insulating layer forming step, the following main curing step may not be provided.

  The curing of the insulating layer in the main curing step is performed by heating.

  The heating temperature in the main curing step is (T + 30) ° C or more and (T + 80) ° C or less. By setting the heating temperature of the resin film when the resin film is fully cured in the above range, it is possible to suppress a decrease in the electrical characteristics of the insulating layer and to improve the transmission performance of the obtained multilayer printed wiring board. .

  The heating temperature in the main curing step is preferably higher than the heating temperature for pre-curing the resin film in the insulating layer forming step, and the resin film is pre-cured in the insulating layer forming step. It is preferable that the temperature is lower than 100 ° C. and higher than the heating temperature.

  The heating temperature in the main curing step is preferably 180 ° C. or higher, more preferably 185 ° C. or higher, still more preferably 190 ° C. or higher, preferably 210 ° C. or lower, more preferably 205 ° C. or lower, and further preferably 200 ° C. or lower. . The heating temperature in the main curing step is preferably (T + 40) ° C. or higher, and more preferably (T + 60) ° C. or lower. When the heating temperature is equal to or higher than the lower limit and equal to or lower than the upper limit, a decrease in the electrical characteristics of the insulating layer can be suppressed, and the transmission performance of the obtained multilayer printed wiring board can be enhanced. In particular, the resin film according to the present invention is suitably used for heating at 190 ° C. or more and 200 ° C. or less to fully cure the resin film to form an insulating layer.

  The heating time in the main curing step is preferably 0.5 hours or more, more preferably 1 hour or more, preferably 2 hours or less, more preferably 1.75 hours or less. When the heating time is equal to or greater than the lower limit and equal to or less than the upper limit, a decrease in electrical characteristics of the insulating layer can be suppressed, and the transmission performance of the obtained multilayer printed wiring board can be increased.

  In the method for manufacturing a multilayer printed wiring board according to the present invention, for example, the insulating layer forming step, the swelling step, the roughening step, the via hole forming step, the desmear processing step, the wiring circuit layer forming step, and By repeating the main curing step, a multilayer printed wiring board can be obtained.

  In the method for manufacturing a multilayer printed wiring board according to the present invention, after performing the step of forming the final insulating-wiring circuit composite layer, the insulating-wiring circuit composite layer is further formed under the same conditions as in the main curing step. May be heated.

  Hereinafter, the method for producing the multilayer printed wiring board according to the present invention, details of the resin film used for the multilayer printed wiring board and each component of the resin film according to the present invention, and the use of the resin film according to the present invention will be described.

[Thermosetting compound]
The resin film contains a thermosetting compound. Examples of the thermosetting compound include styrene compounds, phenoxy compounds, oxetane compounds, epoxy compounds, maleimide compounds, episulfide compounds, (meth) acrylic compounds, phenol compounds, amino compounds, unsaturated polyester compounds, polyurethane compounds, polyphenylene ether compounds, Examples thereof include a divinylbenzyl ether compound, a polyarylate compound, a diallyl phthalate compound, a benzoxazole compound, an acrylate compound, and a silicone compound. Only one kind of the thermosetting compound may be used, or two or more kinds thereof may be used in combination.

  From the viewpoint of enhancing transmission performance, the thermosetting compound preferably contains the epoxy compound or the maleimide compound, and more preferably contains the epoxy compound.

  From the viewpoint of enhancing transmission performance, the maleimide compound is preferably an alkylmaleimide compound.

  Examples of the epoxy compound include a bisphenol A epoxy compound, a bisphenol F epoxy compound, a bisphenol S epoxy compound, a phenol novolak epoxy compound, a biphenyl epoxy compound, a biphenyl novolak epoxy compound, a biphenol epoxy compound, and a naphthalene epoxy compound. , Fluorene type epoxy compound, phenol aralkyl type epoxy compound, naphthol aralkyl type epoxy compound, dicyclopentadiene type epoxy compound, anthracene type epoxy compound, epoxy compound having an adamantane skeleton, epoxy compound having a tricyclodecane skeleton, naphthylene ether type An epoxy compound and an epoxy compound having a triazine nucleus in a skeleton are exemplified.

  From the viewpoint of further lowering the dielectric loss tangent and improving the coefficient of linear thermal expansion (CTE) of the cured product, the epoxy compound preferably contains an epoxy compound having an aromatic skeleton, and has a naphthalene skeleton or a phenyl skeleton. It is preferable that the epoxy compound has an epoxy compound having an aromatic skeleton.

  From the viewpoint of further lowering the dielectric loss tangent and improving the thermal expansion coefficient (CTE) of the cured product and enhancing the flexibility of the resin film and the insulating layer, the epoxy compound is a liquid epoxy compound at 25 ° C. And an epoxy compound which is solid at 25 ° C.

  The viscosity at 25 ° C. of the liquid epoxy compound at 25 ° C. is preferably 1,000 mPa · s or less, more preferably 500 mPa · s or less.

  When measuring the viscosity of the epoxy compound, for example, a dynamic viscoelasticity measuring device (“VAR-100” manufactured by Rheologicals Instruments) is used.

  The molecular weight of the epoxy compound is more preferably 1,000 or less. In this case, a resin material having high fluidity at the time of forming the insulating layer can be obtained even when the content of the inorganic filler in the resin film is 100% by weight and the content of the inorganic filler is 50% by weight or more. For this reason, when the uncured resin material or the B-staged resin film is laminated on the circuit board, the inorganic filler can be uniformly present.

  The molecular weight of the epoxy compound means a molecular weight that can be calculated from the structural formula when the epoxy compound is not a polymer or when the structural formula of the epoxy compound can be specified. When the epoxy compound is a polymer, it means a weight average molecular weight.

  From the viewpoint of further increasing the adhesive strength between the cured product and the wiring circuit layer, the content of the epoxy compound is preferably 20% by weight or more, more preferably 30% by weight, based on 100% by weight of the components excluding the solvent in the resin film. % By weight, preferably 60% by weight or less, more preferably 50% by weight or less.

[Inorganic filler]
The resin film contains an inorganic filler. By using the inorganic filler, the dielectric loss tangent of the cured product is further reduced, and the electrical characteristics can be improved. In addition, the use of the inorganic filler further reduces the dimensional change of the cured product due to heat. As the inorganic filler, only one kind may be used, or two or more kinds may be used in combination.

  Examples of the inorganic filler include silica, talc, clay, mica, hydrotalcite, alumina, magnesium oxide, aluminum hydroxide, aluminum nitride, and boron nitride.

  Reduces the surface roughness of the surface of the cured product, further increases the adhesive strength between the cured product and the wiring circuit layer, forms finer wiring on the surface of the cured product, and provides better insulation reliability with the cured product From the viewpoint of imparting properties, the inorganic filler is preferably silica or alumina, more preferably silica, and even more preferably fused silica. By using silica, the coefficient of thermal expansion of the cured product is further reduced, and the dielectric loss tangent of the cured product is further reduced. In addition, by using silica, the surface roughness of the surface of the cured product is effectively reduced, and the adhesive strength between the cured product and the wiring circuit layer is effectively increased. The shape of the silica is preferably spherical.

  Regardless of the curing environment, advance the curing of the resin, effectively increase the glass transition temperature of the cured product, from the viewpoint of effectively reducing the coefficient of linear thermal expansion of the cured product, the inorganic filler is spherical silica Is preferred.

  The average particle size of the inorganic filler is preferably 50 nm or more, more preferably 100 nm or more, further preferably 500 nm or more, preferably 5 μm or less, more preferably 2 μm or less, and still more preferably 1 μm or less. When the average particle size of the inorganic filler is not less than the lower limit and not more than the upper limit, it is easy to control the surface roughness of the surface of the cured product after the roughening treatment, and the adhesion between the insulating layer and the wiring circuit layer is more improved. Can be further enhanced.

  As the average particle diameter of the inorganic filler, a value of the median diameter (d50) which becomes 50% is adopted. The average particle size can be measured using a laser diffraction scattering type particle size distribution measuring device.

  The inorganic filler is preferably spherical, and more preferably spherical silica. In this case, the surface roughness of the surface of the cured product is effectively reduced, and the adhesive strength between the cured product and the wiring circuit layer is effectively increased. When the inorganic filler is spherical, the aspect ratio of the inorganic filler is preferably 2 or less, more preferably 1.5 or less.

  The inorganic filler is preferably surface-treated, more preferably a surface-treated product with a coupling agent, and even more preferably a surface-treated product with a silane coupling agent. By the surface treatment of the inorganic filler, the surface roughness of the surface of the roughened and cured product is further reduced, and the adhesive strength between the cured product and the wiring circuit layer is further increased. Further, since the inorganic filler is subjected to the surface treatment, finer wiring can be formed on the surface of the cured product, and more favorable inter-wiring insulation reliability and interlayer insulation reliability can be obtained in the cured product. Can be granted.

  Examples of the coupling agent include a silane coupling agent, a titanium coupling agent, and an aluminum coupling agent. Examples of the silane coupling agent include methacryl silane, acryl silane, amino silane, imidazole silane, vinyl silane, and epoxy silane.

  The content of the inorganic filler is preferably 50% by weight or more, more preferably 60% by weight or more, still more preferably 65% by weight or more, particularly preferably 68% by weight, based on 100% by weight of the components excluding the solvent in the resin film. %, Preferably 90% by weight or less, more preferably 80% by weight or less, further preferably 75% by weight or less, particularly preferably 73% by weight or less. When the content of the inorganic filler is equal to or more than the lower limit, the dielectric loss tangent is effectively reduced. When the content of the inorganic filler is equal to or greater than the lower limit and equal to or less than the upper limit, the surface roughness of the surface of the cured product can be further reduced, and finer wiring can be formed on the surface of the cured product. Can be. Further, with this amount of the inorganic filler, it is possible to lower the coefficient of thermal expansion of the cured product and at the same time to improve the smear removal property.

[Curing agent]
The resin film preferably contains a curing agent. The curing agent is not particularly limited. As the curing agent, a conventionally known curing agent can be used. One of the above curing agents may be used alone, or two or more thereof may be used in combination.

  Examples of the curing agent include amine compounds (amine curing agents), thiol compounds (thiol curing agents), imidazole compounds, phosphine compounds, dicyandiamide, phenol compounds (phenol curing agents), cyanate compounds (cyanate curing agents), acid anhydrides, Active ester compounds, carbodiimide compounds (carbodiimide curing agents), benzoxazine compounds (benzoxazine curing agents), and the like can be given. The curing agent preferably has a functional group capable of reacting with the epoxy group of the epoxy compound.

  From the viewpoint of further increasing the thermal dimensional stability and reducing the dielectric loss tangent, the curing agent is at least one of a phenol compound, a cyanate compound, an acid anhydride, an active ester compound, a carbodiimide compound, and a benzoxazine compound. It is preferable to include the component of That is, the resin film preferably contains a curing agent containing at least one component among phenol compounds, cyanate compounds, acid anhydrides, active ester compounds, carbodiimide compounds, and benzoxazine compounds.

  In the present specification, “at least one component among phenol compounds, cyanate compounds, acid anhydrides, active ester compounds, carbodiimide compounds, and benzoxazine compounds” may be referred to as “component X”.

  Therefore, the resin film preferably contains a curing agent containing the component X. As the component X, only one type may be used, or two or more types may be used in combination.

  Examples of the phenol compound include novolak-type phenol, biphenol-type phenol, naphthalene-type phenol, dicyclopentadiene-type phenol, aralkyl-type phenol, and dicyclopentadiene-type phenol.

  Commercially available phenol compounds include novolak phenol ("TD-2091" manufactured by DIC), biphenyl novolak phenol ("MEH-7851" manufactured by Meiwa Kasei), and aralkyl phenol compounds ("MEH" manufactured by Meiwa Kasei). -7800 "), and phenols having an aminotriazine skeleton (" LA1356 "and" LA3018-50P "manufactured by DIC).

  The cyanate compound may be a cyanate ester compound (cyanate ester curing agent).

  Examples of the cyanate ester compound include a novolak-type cyanate ester resin, a bisphenol-type cyanate ester resin, and a prepolymer in which these are partially trimerized. Examples of the novolak type cyanate ester resin include a phenol novolak type cyanate ester resin and an alkylphenol type cyanate ester resin. Examples of the bisphenol type cyanate ester resin include a bisphenol A type cyanate ester resin, a bisphenol E type cyanate ester resin, and a tetramethyl bisphenol F type cyanate ester resin.

  Commercially available cyanate ester compounds include phenol novolak type cyanate ester resins (“PT-30” and “PT-60” manufactured by Lonza Japan) and prepolymers obtained by trimerizing bisphenol type cyanate ester resins (Lonza Japan). “BA-230S”, “BA-3000S”, “BTP-1000S” and “BTP-6020S”).

  Examples of the acid anhydride include tetrahydrophthalic anhydride and an alkylstyrene-maleic anhydride copolymer.

  Commercial products of the above-mentioned acid anhydride include "Rikashid TDA-100" manufactured by Shin Nippon Rika Co., Ltd.

  The active ester compound refers to a compound having at least one ester bond in the structure and having an aliphatic chain, an aliphatic ring, or an aromatic ring bonded to both sides of the ester bond. The active ester compound is obtained, for example, by a condensation reaction of a carboxylic acid compound or a thiocarboxylic acid compound with a hydroxy compound or a thiol compound. Examples of the active ester compound include a compound represented by the following formula (1).

  In the above formula (1), X1 represents a group containing an aliphatic chain, a group containing an aliphatic ring, or a group containing an aromatic ring, and X2 represents a group containing an aromatic ring. Preferred examples of the group containing an aromatic ring include a benzene ring which may have a substituent and a naphthalene ring which may have a substituent. Examples of the substituent include a hydrocarbon group. The number of carbon atoms of the hydrocarbon group is preferably 12 or less, more preferably 6 or less, and still more preferably 4 or less.

  Examples of the combination of X1 and X2 include a combination of a benzene ring which may have a substituent and a benzene ring which may have a substituent, a benzene ring which may have a substituent, And a combination with a naphthalene ring which may have a group. Further, examples of the combination of X1 and X2 include a combination of a naphthalene ring which may have a substituent and a naphthalene ring which may have a substituent.

  The active ester compound is not particularly limited. From the viewpoint of further improving thermal dimensional stability and flame retardancy, the active ester is preferably an active ester compound having two or more aromatic skeletons. From the viewpoint of reducing the dielectric loss tangent of the cured product and increasing the thermal dimensional stability of the cured product, it is more preferable that the active ester has a naphthalene ring in the main chain skeleton.

  Commercial products of the active ester compound include “HPC-8000-65T”, “EXB9416-70BK”, and “EXB8100-65T” manufactured by DIC.

  The carbodiimide compound has a structural unit represented by the following formula (2). In the following formula (2), the right end and the left end are binding sites to other groups. One kind of the carbodiimide compound may be used alone, or two or more kinds may be used in combination.

  In the above formula (2), X is an alkylene group, a group having a substituent bonded to an alkylene group, a cycloalkylene group, a group having a substituent bonded to a cycloalkylene group, an arylene group, or a substituent having been bonded to an arylene group. And p represents an integer of 1 to 5. When there are a plurality of Xs, the plurality of Xs may be the same or different.

  In a preferred embodiment, at least one X is an alkylene group, a group having a substituent bonded to an alkylene group, a cycloalkylene group, or a group having a substituent bonded to a cycloalkylene group.

  Commercially available carbodiimide compounds include Nisshinbo Chemical's "Carbodilite V-02B", "Carbodilite V-03", "Carbodilite V-04K", "Carbodilite V-07", "Carbodilite V-09", and "Carbodilite V-09". 10M-SP "and" Carbodilite 10M-SP (revised) ", as well as" STABAXOL P "," STABAXOL P400 ", and" HIKAZIL 510 "manufactured by Rhine Chemie.

  Examples of the benzoxazine compound include Pd-type benzoxazine and Fa-type benzoxazine.

  Commercially available benzoxazine compounds include "Pd type" manufactured by Shikoku Chemicals.

  The content of the component X is preferably 70 parts by weight or more, more preferably 85 parts by weight or more, preferably 150 parts by weight or less, more preferably 120 parts by weight or less with respect to 100 parts by weight of the thermosetting compound. is there. When the content of the component X is equal to or higher than the lower limit and equal to or lower than the upper limit, the curability is further improved, the thermal dimensional stability is further increased, and the volatilization of the remaining unreacted component can be further suppressed.

  In 100% by weight of the component excluding the inorganic filler and the solvent in the resin film, the total content of the thermosetting compound and the component X is preferably at least 50% by weight, more preferably at least 60% by weight, It is preferably at most 95% by weight, more preferably at most 90% by weight. When the total content of the thermosetting compound and the component X is not less than the lower limit and not more than the upper limit, the curability is more excellent, and the thermal dimensional stability can be further improved.

[Curing accelerator]
The resin film preferably contains a curing accelerator. The use of the curing accelerator further increases the curing speed. By rapidly curing the resin film, the crosslinked structure in the cured product becomes uniform, and the number of unreacted functional groups decreases, resulting in a higher crosslink density. The curing accelerator is not particularly limited, and a conventionally known curing accelerator can be used. One type of the above-mentioned curing accelerator may be used alone, or two or more types may be used in combination.

  Examples of the curing accelerator include anionic curing accelerators such as imidazole compounds, cationic curing accelerators such as amine compounds, and curing accelerators other than anionic and cationic curing accelerators such as phosphorus compounds and organometallic compounds. Agents and the like.

  Examples of the imidazole compound include 2-undecylimidazole, 2-heptadecylimidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl- 2-methylimidazole, 1-benzyl-2-phenylimidazole, 1,2-dimethylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-un Decyl imidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6- [2 ′ -Methyl Midazolyl- (1 ′)]-ethyl-s-triazine, 2,4-diamino-6- [2′-undecylimidazolyl- (1 ′)]-ethyl-s-triazine, 2,4-diamino-6 [2'-ethyl-4'-methylimidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino-6- [2'-methylimidazolyl- (1')]-ethyl-s-triazine Isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-methylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole and 2-phenyl-4-methyl-5-dihydroxymethylimidazole No.

  Examples of the amine compound include diethylamine, triethylamine, diethylenetetramine, triethylenetetramine, 4,4-dimethylaminopyridine, and diazabicyclononene.

  Examples of the phosphorus compound include triphenylphosphine.

  Examples of the organometallic compound include zinc naphthenate, cobalt naphthenate, tin octylate, cobalt octylate, bisacetylacetonatocobalt (II), and trisacetylacetonatocobalt (III).

  From the viewpoint of further lowering the curing temperature, the curing accelerator preferably contains the anionic curing accelerator, and more preferably contains the imidazole compound.

  From the viewpoint of further reducing the curing temperature, the content of the anionic curing accelerator in 100% by weight of the curing accelerator is preferably 20% by weight or more, more preferably 50% by weight or more, and further preferably 80% by weight or more. % Or more, most preferably 100% by weight (total).

  The content of the curing accelerator is not particularly limited. The content of the curing accelerator is preferably 0.01% by weight or more, more preferably 0.05% by weight or more, and preferably 5% by weight or less in 100% by weight of the components excluding the inorganic filler and the solvent in the resin film. , More preferably 3% by weight or less. When the content of the curing accelerator is not less than the lower limit and not more than the upper limit, the resin film is efficiently cured. When the content of the curing accelerator is in the more preferable range, the storage stability of the resin film is further increased, and a more favorable cured product is obtained.

[Thermoplastic resin]
The resin film preferably contains a thermoplastic resin. Examples of the thermoplastic resin include a polyvinyl acetal resin, a phenoxy resin, and a polyimide. The polyimide is preferably a soluble polyimide, and is preferably soluble in other components in the resin film. Only one kind of the thermoplastic resin may be used, or two or more kinds may be used in combination.

  Regardless of the curing environment, the thermoplastic resin is preferably a phenoxy resin or a polyimide from the viewpoint of effectively reducing the dielectric loss tangent and effectively improving the adhesion of the metal wiring. By using a phenoxy resin or a polyimide, it is possible to suppress deterioration of the embedding property of the resin film into holes or irregularities of the circuit board and nonuniformity of the inorganic filler. In addition, by using a phenoxy resin or a soluble polyimide, the dispersibility of the inorganic filler is improved because the melt viscosity can be adjusted, and during the curing process, the resin composition or the B-staged material spreads in an unintended area. It becomes difficult.

  The phenoxy resin contained in the resin film is not particularly limited. As the phenoxy resin, a conventionally known phenoxy resin can be used. The phenoxy resin may be used alone or in combination of two or more.

  Examples of the phenoxy resin include a phenoxy resin having a skeleton such as a bisphenol A skeleton, a bisphenol F skeleton, a bisphenol S skeleton, a biphenyl skeleton, a novolak skeleton, a naphthalene skeleton, and an imide skeleton.

  Commercially available phenoxy resins include, for example, "YP50", "YP55" and "YP70" manufactured by Nippon Steel & Sumitomo Metal Corporation, and "1256B40", "4250", "4256H40", and "4256H40" manufactured by Mitsubishi Chemical Corporation. 4275 "," YX6954BH30 "and" YX8100BH30 ".

  From the viewpoint of obtaining a resin film having better storage stability, the weight average molecular weight of the thermoplastic resin and the phenoxy resin is preferably 5,000 or more, more preferably 10,000 or more, preferably 100,000 or less, more preferably 50,000 or less. It is.

  The weight average molecular weight of the thermoplastic resin and the phenoxy resin indicates a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

  The contents of the thermoplastic resin and the phenoxy resin are not particularly limited. The content of the thermoplastic resin (when the thermoplastic resin is a phenoxy resin, the content of the phenoxy resin) is preferably 1% in 100% by weight of the components excluding the inorganic filler and the solvent in the resin film. %, More preferably 2% by weight or more, preferably 30% by weight or less, more preferably 20% by weight or less. When the content of the thermoplastic resin is equal to or more than the lower limit and equal to or less than the upper limit, the embedding property of the resin film into holes or irregularities of the circuit board is improved. When the content of the thermoplastic resin is equal to or more than the above lower limit, formation of a resin film is further facilitated, and a better insulating layer is obtained. When the content of the thermoplastic resin is equal to or less than the upper limit, the coefficient of thermal expansion of the cured product is further reduced. When the content of the thermoplastic resin is equal to or less than the upper limit, the surface roughness of the surface of the cured product is further reduced, and the adhesive strength between the cured product and the wiring circuit layer is further increased.

[solvent]
The resin film does not contain or contains a solvent. By using the solvent, the viscosity of the resin film can be controlled in a suitable range, and the coating property of the resin film can be improved. Further, the solvent may be used to obtain a slurry containing the inorganic filler. The solvent may be used alone or in combination of two or more.

  Examples of the solvent include acetone, methanol, ethanol, butanol, 2-propanol, 2-methoxyethanol, 2-ethoxyethanol, 1-methoxy-2-propanol, 2-acetoxy-1-methoxypropane, toluene, xylene, methyl ethyl ketone, Examples thereof include N, N-dimethylformamide, methyl isobutyl ketone, N-methyl-pyrrolidone, n-hexane, cyclohexane, cyclohexanone and naphtha which is a mixture.

  Most of the solvent is preferably removed when the resin composition is formed into a film. Therefore, the boiling point of the solvent is preferably 200 ° C. or lower, more preferably 180 ° C. or lower. The content of the solvent in the resin composition is not particularly limited. The content of the solvent can be appropriately changed in consideration of the coatability of the resin composition and the like.

[Other components]
For the purpose of improving impact resistance, heat resistance, compatibility of resin, workability, and the like, the above resin film includes a leveling agent, a flame retardant, a coupling agent, a coloring agent, an antioxidant, an ultraviolet ray deterioration inhibitor, A foaming agent, a thickener, a thixotropic agent and the like may be added.

  Examples of the coupling agent include a silane coupling agent, a titanium coupling agent, and an aluminum coupling agent. Examples of the silane coupling agent include vinyl silane, amino silane, imidazole silane and epoxy silane.

(Resin film)
By molding the resin composition into a film, a resin film (B-staged product / B-stage film) is obtained. The resin film is preferably a B-stage film. The resin film is preferably a thermosetting resin film.

  As a method of forming the resin composition into a film shape to obtain a resin film, the following method is exemplified. An extrusion molding method in which a resin composition is melt-kneaded using an extruder, extruded, and then formed into a film by a T-die or a circular die. A casting method in which a resin composition containing a solvent is cast to form a film. Other known film forming methods. The extrusion molding method or the casting molding method is preferable because it can cope with thinning. The film includes a sheet.

  The resin composition which is a B-stage film can be obtained by forming the resin composition into a film and heating and drying at 50 ° C. to 150 ° C. for 1 minute to 10 minutes to such an extent that curing by heat does not proceed excessively. it can.

  The film-shaped resin composition obtained by the above-described drying step is referred to as a B-stage film. The B stage film is in a semi-cured state. The semi-cured product is not completely cured, and curing may proceed further.

  The resin film need not be a prepreg. When the resin film is not a prepreg, migration does not occur along a glass cloth or the like. Further, when laminating or pre-curing the resin film, the surface does not have irregularities due to the glass cloth. The resin film can be used in the form of a laminated film including a metal foil or a base material and a resin film laminated on the surface of the metal foil or the base material. The metal foil is preferably a copper foil.

  Examples of the base material of the laminated film include polyester resin films such as polyethylene terephthalate film and polybutylene terephthalate film, olefin resin films such as polyethylene film and polypropylene film, and polyimide resin films. The surface of the base material may be subjected to a release treatment, if necessary.

  From the viewpoint of more uniformly controlling the degree of cure of the resin film, the thickness of the resin film is preferably 5 μm or more, and more preferably 200 μm or less. When the resin film is used as an insulating layer of a circuit, the thickness of the insulating layer formed by the resin film is preferably equal to or greater than the thickness of a conductor layer (wiring circuit layer) forming a circuit. The thickness of the insulating layer is preferably 5 μm or more, and more preferably 200 μm or less.

  The arithmetic average roughness Ra of the surface of the cured product of the resin film is preferably 10 nm or more, preferably less than 300 nm, more preferably less than 200 nm, and even more preferably less than 150 nm. In this case, the adhesive strength between the cured product and the wiring circuit layer increases, and further finer wiring is formed on the surface of the insulating layer. Furthermore, conductor loss can be suppressed, and signal loss can be suppressed low. The arithmetic average roughness Ra is measured according to JIS B0601: 1994.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. The present invention is not limited to the following examples.

(Thermosetting compound)
Epoxy compound:
Biphenyl type epoxy compound ("NC-3000" manufactured by Nippon Kayaku)
Naphthalene type epoxy compound ("HP-4032D" manufactured by DIC)
Naphthol aralkyl epoxy compound (“ESN-475V” manufactured by Nippon Steel & Sumitomo Metal Corporation)
Maleimide compound:
N-phenylmaleimide compound ("BMI-4000" manufactured by Daiwa Chemical Industry Co., Ltd.)
N-alkyl bismaleimide compound (“BMI-1500” manufactured by Designer Molecular Inc.)

(Inorganic filler)
Silica-containing slurry (silica 75% by weight: “SC4050-HOA” manufactured by Admatechs, average particle size 1.0 μm, aminosilane treatment, cyclohexanone 25% by weight)

(Curing agent)
Component X:
Phenol novolak compound ("LA-1356" manufactured by DIC)
Liquid containing active ester compound ("EXB-9416-70BK" manufactured by DIC, solid content 70% by weight)
Liquid containing carbodiimide compound (“V-03” manufactured by Nisshinbo Chemical Inc., solid content 50% by weight)
Benzoxazine compound (“Pd type” manufactured by Shikoku Chemicals)

(Curing accelerator)
Diazabicyclononene (DBN)
Dimethylaminopyridine (“DMAP” manufactured by Wako Pure Chemical Industries, Ltd.)
Imidazole compound (2-phenyl-4-methylimidazole, "2P4MZ" manufactured by Shikoku Chemicals, anionic curing accelerator)

(Thermoplastic resin)
Polyimide compound (soluble polyimide):
A polyimide-containing solution (non-volatile content: 26.8% by weight), which is a reaction product of tetracarboxylic dianhydride and dimer diamine, was synthesized according to Synthesis Example 1 below.

(Synthesis example 1)
In a reaction vessel equipped with a stirrer, a water separator, a thermometer and a nitrogen gas inlet tube, 300.0 g of tetracarboxylic dianhydride (“BisDA-1000” manufactured by SABIC Japan GK) and 665.5 g of cyclohexanone were placed. And the solution in the reaction vessel was heated to 60 ° C. Next, 89.0 g of dimer diamine ("PRIAMINE 1075", manufactured by Croda Japan) and 54.7 g of 1,3-bisaminomethylcyclohexane (manufactured by Mitsubishi Gas Chemical Company) were dropped into the reaction vessel. Next, 121.0 g of methylcyclohexane and 423.5 g of ethylene glycol dimethyl ether were added to the reaction vessel, and an imidization reaction was performed at 140 ° C. for 10 hours. Thus, a polyimide compound-containing solution (non-volatile content: 26.8% by weight) was obtained. The molecular weight (weight average molecular weight determined by the following GPC measurement) of the obtained polyimide compound was 20,000. The molar ratio of the acid component / amine component was 1.04.

GPC (gel permeation chromatography) measurement:
Using a high performance liquid chromatograph system manufactured by Shimadzu Corporation, the measurement was performed at a column temperature of 40 ° C. and a flow rate of 1.0 ml / min using tetrahydrofuran (THF) as a developing medium. "SPD-10A" was used as a detector, and two columns of "KF-804L" (exclusion limit molecular weight: 400,000) manufactured by Shodex were connected in series. The weight average molecular weight Mw = 354,000, 189,000, 98,900, 37,200, 17,100, 9,830, 5,870,2, using "TSK standard polystyrene" manufactured by Tosoh Corporation as standard polystyrene. Calibration curves were created using 500, 1,050, 500 substances and molecular weights were calculated.

(Examples 1 to 3 and Comparative Examples 1 and 2)
The components shown in Table 1 below were blended in the amounts shown in Table 1 (units: parts by weight of solids), and stirred at room temperature until a uniform solution was obtained, to obtain a resin material.

Preparation of resin film:
Using an applicator, the obtained resin material was applied on the release-treated surface of a release-treated PET film (“XG284” manufactured by Toray Industries, Inc., thickness: 25 μm), and then, in a gear oven at 100 ° C. for 3 minutes. Dry and evaporate the solvent. Thus, a laminated film (a laminated film of a PET film and a resin film) in which a resin film (B-stage film) having a thickness of 40 μm was laminated on the PET film was obtained.

(Evaluation)
(1) Peak temperature T
The exothermic peak accompanying the curing of the obtained resin film (B-stage film) was evaluated using a differential scanning calorimeter ("Q2000" manufactured by TA Instruments). 8 mg of the resin film was placed in a special aluminum pan, and capped with a special jig. This dedicated aluminum pan and an empty aluminum pan (reference) are set in a heating unit, and heated at a rate of 3 ° C./min from −30 ° C. to 250 ° C. in a nitrogen atmosphere, reverse heat flow and non-reverse flow. The heat flow was observed. The exothermic peak observed in the non-reverse heat flow was defined as the exothermic peak of the resin film. Among the obtained exothermic peaks, the peak temperature T of the exothermic peak having the maximum peak height among the exothermic peaks having exothermic peak top temperatures of 130 ° C. or more and 200 ° C. or less was determined.

(2) Dielectric loss tangent The obtained resin film was cut into a size of 2 mm in width and 80 mm in length, and five sheets were overlapped to obtain a laminate having a thickness of 200 µm.

  The obtained laminate was heated at 130 ° C. for 1 hour to obtain a pre-cured resin film. This resin film was heated at (T + 50) ° C. for 1.5 hours to obtain a cured resin film (1).

  The obtained laminate was heated at 130 ° C. for 1 hour to obtain a pre-cured resin film. This resin film was heated at (T + 50) ° C. for 7.5 hours to obtain a cured product (2) of the resin film (a heating time five times longer than the heating time of the cured product (1) of the resin film). ).

  The obtained laminate was heated at 130 ° C. for 1 hour to obtain a pre-cured resin film. The resin film was heated at (T + 50) ° C. for 15 hours to obtain a cured product (3) of the resin film (a heating time ten times longer than the heating time of the cured product (1) of the resin film).

  The above T at the above curing temperature means a peak temperature T. As shown in Table 1, the resin film was cured in an air environment or a nitrogen environment.

  For the cured products (1) to (3) of the obtained resin films, using “Cavity Resonance Perturbation Method Permittivity Measurement Apparatus CP521” manufactured by Kanto Electronics Application Development Co., Ltd. and “Network Analyzer N5224A PNA” manufactured by Keysight Technology, Inc. The dielectric loss tangent was measured at room temperature (23 ° C.) at a frequency of 10 GHz by the cavity resonance method.

The measured dielectric loss tangent Df of the cured resin film (1) is _{1.5 h} , the dielectric loss tangent Df of the cured resin film (2) is _{7.5 h,} and the dielectric loss tangent Df of the cured resin film (3) is _{15 h.} From the above, the following was calculated.

The ratio of Df _7.5h to Df _1.5h (Df _7.5h / Df _1.5h )
Ratio of Df _15h to Df _1.5h (Df _15h / Df _1.5h )

[Judgment criteria for dielectric loss tangent]
A: Ratio (Df _7.5h / Df _1.5h ) is 0.9 or more and 1.15 or less B: Ratio (Df _7.5h / Df _1.5h ) is less than 0.9 or 1.15 A: ratio (Df _15h / Df _1.5h ) is 0.9 or more and 1.2 or less B: ratio (Df _15h / Df _1.5h ) is less than 0.9 or exceeds 1.2

(3) Transmission Loss An evaluation board for measuring a transmission loss (an evaluation board including a copper-clad laminate and six insulating-wiring circuit composite layers) was prepared as follows.

Formation of the first insulation-wiring circuit composite layer:
(A1) Laminating step:
A double-sided copper-clad laminate (a copper foil thickness of 18 μm on each surface, a substrate thickness of 0.7 mm, a substrate size of 100 mm × 100 mm, “MCL-E679FG” manufactured by Hitachi Chemical Co., Ltd.) was prepared. Both surfaces of the copper foil surface of this double-sided copper-clad laminate were immersed in “Cz8101” manufactured by MEC to roughen the surface of the copper foil. The resin film (B stage film) side of the laminated film is copper-clad laminated on both sides of the roughened copper-clad laminate using “Machine Seisakusho's“ batch type vacuum laminator MVLP-500 / 600-IIA ””. They were laminated on a board. The laminating conditions were such that the pressure was reduced to 13 hPa or less by reducing the pressure for 30 seconds, and then the pressing was performed at 100 ° C. and a pressure of 0.4 MPa for 30 seconds. After peeling off the PET film, it was heated at 130 ° C. for 60 minutes to semi-cure (preliminarily cure) the resin film. Thus, a laminate (1) in which the semi-cured resin film was laminated on the CCL substrate was obtained.

(B1) Via-hole forming step:
Using a CO ₂ laser beam machine (“LC-4KF212” manufactured by Via Mechanics Co., Ltd.), a via hole having a diameter of about 60 μm was formed under the conditions of burst mode, energy 0.4 mJ, pulse 27 μsec, and 3 shots.

(C1) Desmear treatment and roughening treatment:
(C1-1) Swelling treatment:
The obtained laminate (1) was placed in a swelling liquid at 60 ° C. (“Swelling Dip Securiganto P” manufactured by Atotech Japan) and rocked for 10 minutes. Thereafter, the substrate was washed with pure water.

(C1-2) Permanganate treatment (roughening treatment and desmear treatment):
The layered product (1) after the swelling treatment was put into a roughened aqueous solution of potassium permanganate (“Concentrate Compact CP” manufactured by Atotech Japan) at 80 ° C. and rocked for 30 minutes. Next, after treating for 2 minutes using a cleaning liquid at 25 ° C. (“Reduction Securiganto P” manufactured by Atotech Japan Co., Ltd.), the substrate was washed with pure water to obtain a laminate (1) after a roughening treatment.

(C1-3) Measurement of surface roughness:
The surface of the layered product (1) (cured material subjected to the roughening treatment) after the roughening treatment was measured using a non-contact three-dimensional surface shape measuring device (“Contour GT-K” manufactured by Bruker) to 95.6 μm × The arithmetic average roughness Ra was measured in a measurement area of 71.7 μm. The arithmetic average roughness Ra was measured in accordance with JIS B0601: 1994. It was confirmed that the surface roughness of the roughened cured product was 200 nm or less.

(D1) Electroless plating treatment:
The surface of the cured product of the laminate (1) after the roughening treatment was treated with an alkaline cleaner at 60 ° C. (“Cleaner Securigant 902” manufactured by Atotech Japan) for 5 minutes, and degreased and washed. After washing, the cured product was treated with a pre-dip liquid at 25 ° C. (“Pre-Dip Neo Gant B” manufactured by Atotech Japan) for 2 minutes. Thereafter, the cured product was treated with an activator solution ("Activator Neo Gant 834" manufactured by Atotech Japan) at 40 ° C for 5 minutes to attach a palladium catalyst. Next, the cured product was treated with a reducing solution at 30 ° C. (“Reducer Neogant WA” manufactured by Atotech Japan) for 5 minutes.

  Next, the cured product is placed in a chemical copper solution (“Basic Print Gant MSK-DK”, “Copper Print Gant MSK”, “Stabilizer Print Gant MSK”, and “Reducer Cu” manufactured by Atotech Japan), and electroless plating is performed. Was carried out until the plating thickness became about 0.5 μm. After the electroless plating, annealing was performed at a temperature of 120 ° C. for 30 minutes in order to remove the remaining hydrogen gas. In addition, all the processes up to the process of the electroless plating were performed while making the treatment liquid 2 L on a beaker scale and oscillating the cured product.

(E1) Resist formation:
A dry film resist (“RY5125” manufactured by Hitachi Chemical Co., Ltd.) was attached using a hot roll laminator. The laminating conditions were such that the temperature was 100 ° C., the pressure was 0.4 MPa, and the laminating speed was 1.5 m / min. Next, after exposure at 85 mJ / cm ² , development was performed by spraying a 1 wt% aqueous solution of sodium carbonate at 27 ° C. and a spray pressure of 1.2 MPa for 30 seconds.

(F1) Electroplating treatment:
Next, electrolytic plating was performed on the cured product subjected to the electroless plating until the plating thickness became 25 μm. Copper sulfate solution ("Copper sulfate pentahydrate" manufactured by Wako Pure Chemical Industries, "Sulfuric acid" manufactured by Wako Pure Chemical Industries, "Basic Leveler Capparaside HL" manufactured by Atotech Japan, "Atotech Japan" A current of 0.6 A / cm ² was passed using a compensating agent Capparaside GS ”) to perform electrolytic plating until the plating thickness became about 25 μm.

(G1) DFR peeling and etching treatment:
The dry film resist (DFR) was peeled off by spraying using a 3 wt% aqueous solution of sodium hydroxide. Next, quick etching was performed using a persulfuric acid-based acidic etching solution (“SAC process” manufactured by JCU).

(H1) Full curing step:
It heated at (T + 50) degreeC with respect to the peak temperature T for 1.5 hours.

  Thus, the first insulating-wiring circuit composite layer was formed on the copper-clad laminate.

Formation of the second insulation-wiring circuit composite layer:
(A2) Laminating step:
(A1) The first wiring circuit layer was subjected to the roughening treatment under the same conditions as the roughening treatment performed in the laminating step. Thereafter, the resin film (B-stage film) side of the laminated film was laminated on the first insulating-wiring circuit composite layer under the laminating conditions performed in the (a1) laminating step. Then, after peeling off the PET film, the resin film was pre-cured by heating at 130 ° C. for 60 minutes. Thus, a laminate (2) in which a semi-cured resin film was laminated on the first insulating-wiring circuit composite layer was obtained.

(B2) Via hole forming step:
(B1) A via hole was formed in the same manner as in the step of forming the via hole except that the layered product (1) was changed to the layered product (2).

(C2) Desmear treatment and roughening treatment:
(C1) The laminate (2) after the roughening treatment was obtained in the same manner as the steps performed in the desmear treatment and the roughening treatment, except that the laminate (1) was changed to the laminate (2).

(D2) Electroless plating treatment:
(D1) The electroless plating treatment was performed in the same manner except that the step performed in the electroless plating treatment was changed from the roughened laminate (1) to the roughened laminate (2). Was.

(F2) Electroplating treatment:
(D2) After performing the electroless plating treatment, the electroless plating treatment was performed in the same manner as in (f1) electrolytic plating treatment.

(H2) Full curing step:
(H1) Heated at (T + 50) ° C. for 1.5 hours in the same manner as in the main curing step.

  Thus, a second insulating-wiring circuit composite layer was formed on the first insulating-wiring circuit composite layer.

Formation of third insulating-wiring circuit composite layer:
A third insulating-wiring circuit composite layer was formed on the second insulating-wiring circuit composite layer in the same manner as in the step of forming the second insulating-wiring circuit composite layer.

Formation of fourth insulation-wiring circuit composite layer:
A fourth insulating-wiring circuit composite layer was formed on the third insulating-wiring circuit composite layer in the same manner as in the step of forming the second insulating-wiring circuit composite layer.

Formation of the fifth insulation-wiring circuit composite layer:
(A5) Laminating step:
(A2) A laminate (5) was obtained in which a semi-cured resin film was laminated on the fourth insulating-wiring circuit composite layer in the same manner as in the laminating step.

(B5) Via hole forming step:
(B1) A via hole was formed in the same manner as in the step of forming the via hole, except that the laminate (1) was changed to the laminate (5).

(C5) Desmear treatment and roughening treatment:
(C1) A laminate (5) after the roughening treatment was obtained in the same manner as the steps performed in the desmear treatment and the roughening treatment, except that the laminate (1) was changed to the laminate (5).

(D5) Electroless plating treatment:
(D1) The electroless plating was performed in the same manner except that the step performed in the electroless plating was changed from the layered body (1) after the roughening to the layered body (5) after the roughening. Was.

(E5) Resist formation:
(E1) Development was performed in the same manner as in the step of forming the resist.

(F5) Electroplating treatment:
After the pattern of the dry film resist was formed, an electroless plating process was performed in the same manner as the (f1) electrolytic plating process.

(G5) DFR peeling and etching treatment:
(G1) DFR peeling and etching were performed in the same manner as in the steps performed in DFR peeling and etching.

(H5) Main curing step:
(H1) Heated at (T + 50) ° C. for 1.5 hours in the same manner as in the main curing step.

  Thus, a fifth insulating-wiring circuit composite layer was formed on the fourth insulating-wiring circuit composite layer.

Formation of sixth insulation-wiring circuit composite layer:
A sixth insulating-wiring circuit composite layer was formed on the fifth insulating-wiring circuit composite layer in the same manner as in the step of forming the second insulating-wiring circuit composite layer.

  In this way, an evaluation substrate having the first to sixth insulating-wiring circuit composite layers formed on the copper-clad laminate was produced. In the obtained evaluation board, only the first and fifth wiring circuit layers among the first to sixth wiring circuit layers have patterns. The first and fifth wiring circuit layers are signal layers.

  FIG. 5 is a schematic partial cross-sectional view showing, in an enlarged manner, the vicinity of a signal layer of each of the evaluation substrates manufactured in Examples and Comparative Examples. In FIG. 5, reference numeral 43 indicates a wiring circuit layer (signal layer), reference numerals 41 and 45 indicate wiring circuit layers (ground layers) different from the signal layer, and reference numerals 42 and 44 indicate insulating layers. In the obtained evaluation substrate, the width W1 of the upper surface and the width W2 of the lower surface of the signal layer 43 were each 20 μm, the thickness t of the signal layer 43 was 15 μm, and the thicknesses H1 and H2 of the insulating layer were each 30 μm. .

  The transmission loss of the transmission line of the first wiring circuit layer (signal layer) and the transmission line of the fifth wiring circuit layer (signal layer) were measured according to the following procedure.

Evaluation of transmission loss:
The obtained evaluation board is placed on a measurement table of a probe station M150 (manufactured by Cascade Microtech) on which a 40 GHz air coplanar probe (“ACP40-A-GSG-150” manufactured by Cascade Microtech) is set. did. Next, after calibrating the measurement system using an LRM impedance reference substrate (manufactured by Cascade Microtech) and “Vector Network Analyzer N5224A” manufactured by Keysight Technology, a 40 GHz air coplanar is placed at a measurement point on the evaluation substrate. -The probe was brought into contact with both end pads of the transmission path. Using the key site Technologies Inc. "Vector Network Analyzer N5224A", in the range of 40GHz the frequency 100 MHz, the absolute value IL ₁ and 5 layer wiring circuit of the transmission loss of the first wiring circuit layer (signal layer) the absolute value IL ₅ of the transmission loss of the layer (signal layer) was measured. Note that the transmission loss was obtained by calculating 20 Log (S21) from S12 (calculated from Touchstone Format) measured by a vector network analyzer.

[Transmission loss criteria]
：: The ratio of IL ₁ to IL _{5 at} 38 GHz (IL ₁ / IL ₅ ) was 0.96 or more and 1.05 or less. ×: The ratio of IL ₁ to IL _{5 at} 38 GHz (IL ₁ / IL ₅ ) was 1.05. Exceed

  The composition and results are shown in Table 1 below. In this evaluation, the transmission measurement of each layer is experimentally performed, but if there is a large difference in this value, it is considered that the transmission loss in the actual substrate also increases.

DESCRIPTION OF SYMBOLS 1 ... Multilayer printed wiring board 11 ... Substrate 11a ... Hole 12 ... Wiring circuit layer 13, 13A, 13B ... Insulating layer (1st insulating layer)
14. Wiring circuit layer (first wiring circuit layer)
15, 15A, 15B ... insulating layer (second insulating layer)
16. Wiring circuit layer (second wiring circuit layer)
17 ... insulating layer (third insulating layer)
18. Wiring circuit layer (third wiring circuit layer)
19 ... insulating layer (fourth insulating layer)
20: Wiring circuit layer (fourth wiring circuit layer)
21 ... insulating layer (fifth insulating layer)
22. Wiring circuit layer (fifth wiring circuit layer)
23 ... insulating layer (sixth insulating layer)
24. Wiring circuit layer (sixth wiring circuit layer)
31: Solder resist film 41: Wiring circuit layer (ground layer)
42: insulating layer 43: wiring circuit layer (signal layer)
44: insulating layer 45: wiring circuit layer (ground layer)
51, 52 ... resist pattern

Claims (10)

A method of manufacturing a multilayer printed wiring board having a structure in which insulating layers and wiring circuit layers are alternately stacked on a circuit board,
A method of manufacturing a multilayer printed wiring board to form a plurality of insulating layers using a resin film,
Forming a first insulating layer using a resin film on a circuit board, and forming a first wiring circuit layer on the first insulating layer, forming a first insulating-wiring circuit; Forming a composite layer;
Forming a second insulating layer using a resin film on the first insulating-wiring circuit composite layer, and forming a second wiring circuit layer on the second insulating layer; Forming a second insulating-wiring circuit composite layer;
Forming a third insulating layer using a resin film on the second insulating-wiring circuit composite layer, and forming a third wiring circuit layer on the third insulating layer; Forming a third insulating-wiring circuit composite layer;
Forming a fourth insulating layer using a resin film on the third insulating-wiring circuit composite layer, and forming a fourth wiring circuit layer on the fourth insulating layer; Forming a fourth insulation-wiring circuit composite layer;
Forming a fifth insulating layer using a resin film on the fourth insulating-wiring circuit composite layer, and forming a fifth wiring circuit layer on the fifth insulating layer; Forming a fifth insulating-wiring circuit composite layer;
Forming a sixth insulating layer using a resin film on the fifth insulating-wiring circuit composite layer, and forming a sixth wiring circuit layer on the sixth insulating layer; Forming a sixth insulation-wiring circuit composite layer;
The resin film includes a thermosetting compound and an inorganic filler,
The resin film has an exothermic peak top temperature of 130 ° C. or more and 200 ° C. or less, as measured by a differential scanning calorimeter,
When the peak temperature of the exothermic peak having the maximum peak height among the exothermic peaks having exothermic peak top temperatures of 130 ° C. or more and 200 ° C. or less is T ° C., the insulation-wiring of the first to sixth layers is used. In each of the steps of forming the circuit composite layer, a heating temperature for fully curing the resin film is (T + 30) ° C or more and (T + 80) ° C or less,
The absolute value of the transmission loss of the first wiring circuit layers in the resulting multi-layer printed wiring board as IL _1,
The absolute value of the transmission loss of 5-layer wiring circuit layer in a multilayer printed wiring board when the IL ₅ obtained,
A method for manufacturing a multilayer printed wiring board, wherein the ratio of IL ₁ to IL ₅ is 0.96 or more and 1.05 or less. The dielectric loss tangent in the frequency 10GHz of first insulating layers in the resulting multi-layer printed wiring board as Df _1,
The dielectric loss tangent in the frequency 10GHz five-layer insulating layer when the Df ₅ in the resulting multi-layer printed wiring board,
The ratio Df ₅ of Df _1, to 0.9 to 1.15, a method for manufacturing a multilayer printed wiring board according to claim 1.   The method for producing a multilayer printed wiring board according to claim 1, wherein the heating temperature for fully curing the resin film is 190 ° C. or more and 200 ° C. or less.   Forming an insulating layer using a resin film on the insulating-wiring circuit composite layer and repeating the process of forming the wiring circuit layer on the insulating layer to form seven or more insulating-wiring circuit composite layers The method for producing a multilayer printed wiring board according to any one of claims 1 to 3.   The method for manufacturing a multilayer printed wiring board according to any one of claims 1 to 4, wherein the thermosetting compound includes an epoxy compound. Including a thermosetting compound and an inorganic filler,
In the measurement with a differential scanning calorimeter, the exothermic peak top temperature is 130 ° C or more and 200 ° C or less,
Of the exothermic peak having an exothermic peak top temperature of 130 ° C. or more and 200 ° C. or less, a peak temperature of an exothermic peak having a maximum peak height is defined as T ° C.,
The dielectric loss tangent at a frequency of 10 GHz of the cured product of the resin film cured at (T + 50) ° C. for 1.5 hours is Df _1.5h ,
When the dielectric loss tangent at a frequency of 10 GHz of the cured product of the resin film cured at (T + 50) ° C. for 7.5 hours is Df _7.5h ,
A resin film wherein the ratio of Df _7.5h to Df _1.5h is 0.9 or more and 1.15 or less.   The resin film according to claim 6, wherein the thermosetting compound includes an epoxy compound.   The resin film according to claim 6, wherein the resin film is heated to 190 ° C. or more and 200 ° C. or less to fully cure the resin film to form an insulating layer.   The multilayer printed wiring board having a structure in which insulating layers and wiring circuit layers are alternately stacked on a circuit board, the multilayer printed wiring board being used to form a plurality of insulating layers. 3. The resin film according to 1. Comprising a circuit board, an insulating layer formed of a resin film, and a wiring circuit layer,
On the circuit board, having a structure in which the insulating layer and the wiring circuit layer are alternately laminated,
A first insulating-wiring circuit composite layer composed of a first insulating layer and a first wiring circuit layer, and a second insulating layer and a second wiring circuit on the circuit board. A second insulating-wiring circuit composite layer composed of layers, a third insulating-wiring circuit composite layer composed of a third insulating layer and a third wiring circuit layer, and a fourth layer The fourth insulation-wiring circuit composite layer composed of the insulating layer and the fourth wiring circuit layer, and the fifth insulation layer composed of the fifth insulating layer and the fifth wiring circuit layer -Having at least a wiring circuit composite layer and a sixth insulating-wiring circuit composite layer composed of a sixth insulating layer and a sixth wiring circuit layer;
The resin film includes a thermosetting compound and an inorganic filler,
The resin film has an exothermic peak top temperature of 130 ° C. or more and 200 ° C. or less, as measured by a differential scanning calorimeter,
The absolute value of the transmission loss of the first wiring circuit layer and IL _1,
The absolute value of the transmission loss of 5-layer wiring circuit layer is taken as IL _5,
A multilayer printed wiring board, wherein the ratio of IL ₁ to IL ₅ is 0.96 or more and 1.05 or less.

Images