JP6978472B2 - Manufacturing method of multi-layer printed wiring board, resin film and multi-layer printed wiring board - Google Patents

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 made of a resin material may be used to form an insulating layer for insulating the internal layers and to form an insulating layer located on the surface layer portion. be. Wiring, which is generally metal, is laminated on the surface of the insulating layer.

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 a wiring circuit layer. (2) A step of curing a resin film to form an insulating layer. (3) A step of arranging 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 a plating process and an etching process, or may be a wiring circuit formed by a laser method or an inkjet method.

As an example of the 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 this curable epoxy composition (resin film) can be used as an insulating layer of a multilayer printed wiring board or the like.

JP-A-2015-143302

In the method for manufacturing a multilayer printed wiring board, an insulating layer is formed by heating and curing a resin film. Therefore, when the above steps (1) to (3) are repeated, the resin film laminated in the early stage is heated more times and for a longer time than the resin film laminated in the later stage. When the resin film (insulating layer) is repeatedly heated, the dimensional stability (linear expansion coefficient) of the insulating layer may change. As a result, in the obtained multilayer printed wiring board, a difference may occur in the linear expansion coefficient of the insulating layer of each layer, and cracks or cracks may occur in the insulating layer and the wiring circuit layer. In particular, in the vicinity of the via hole, stress is likely to be concentrated, and cracks or cracks in the insulating layer and the wiring circuit layer (connection portion between the wiring circuit layers) of the via portion are more likely to occur. Cracks or cracks in the insulation layer and wiring circuit layer can reduce connection reliability.

If the heating temperature in the latter stage is moderated in order to suppress the change in the dimensional stability (linear expansion coefficient) of the insulating layer formed by being laminated in the initial stage, the resin material laminated in the later stage is sufficiently cured. It is difficult to make it. Further, it is not preferable to moderate the heating temperature in the latter stage and to heat for a long time because the production time becomes long.

Further, since the insulating layer is exposed to a high temperature (for example, 260 ° C. or higher) during the reflow step, if the linear expansion coefficients of the laminated insulating layers are different, the insulating layer and the wiring circuit layer (particularly the insulating layer around the via hole). And the wiring circuit layer of the via part) is prone to cracking or cracking.

With conventional resin materials, it is difficult to reduce the change in dimensional stability (linear expansion coefficient) between the insulating layer formed by being laminated in the early stage and the insulating layer formed by being laminated in the later stage. Therefore, with the conventional resin material, it is difficult to prevent the occurrence of cracks or cracks in the insulating layer, and in particular, it is even more difficult to prevent the occurrence of cracks or cracks in the insulating layer around the via hole. Further, with the conventional resin material, it is difficult to prevent the occurrence of cracks or cracks in the wiring circuit layer, and in particular, it is even more difficult to prevent the occurrence of cracks or cracks in the wiring circuit layer in the via portion.

An object of the present invention is to provide a resin film capable of preventing the occurrence of cracks or cracks in the insulating layer around the via hole and the wiring circuit layer in the via portion, and improving the connection reliability. Another object of the present invention is to provide a multilayer printed wiring board and a method for manufacturing a multilayer printed wiring board using the above resin film.

According to a broad aspect of the present invention, there 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, and a plurality of insulations are made by using a resin film. It is a method of manufacturing a multilayer printed wiring board for forming a layer, in which a first-layer insulating layer is formed on a circuit board by using a resin film, and a first-layer wiring circuit is formed on the first insulating layer. A step of forming a layer to form a first layer of an insulating-wiring circuit composite layer and a second layer of an insulating layer using a resin film on the first layer of the insulating-wiring circuit composite layer are formed. In addition, a step of forming a second wiring circuit layer on the second insulating layer to form a second insulating-wiring circuit composite layer and a step of forming a second insulating-wiring circuit composite layer on the second insulating-wiring circuit composite layer. , A third insulating layer is formed using a resin film, and a third wiring circuit layer is formed on the third insulating layer to form a third insulating-wiring circuit composite layer. And the fourth layer of the insulation circuit layer is formed on the third layer of the insulation-wiring circuit composite layer by using a resin film, and the fourth layer of the wiring circuit layer is formed on the fourth layer of the insulation layer. The step of forming the fourth layer of the insulation-wiring circuit composite layer and the fifth layer of the insulation-wiring circuit composite layer using a resin film are formed on the fourth layer of the insulation-wiring circuit composite layer. A step of forming a fifth wiring circuit layer on the fifth insulating layer to form a fifth insulating-wiring circuit composite layer, and a resin on the fifth insulating-wiring circuit composite layer. A step of forming a sixth insulating layer using a film and forming a sixth wiring circuit layer on the sixth insulating layer to form a sixth insulating-wiring circuit composite layer. The resin film contains a thermosetting compound and an inorganic filler, and the resin film has an exothermic peak top temperature of 130 ° C. or higher and 200 ° C. or lower as measured by a differential scanning calorimeter. 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 exothermic peak having the maximum peak height is T ° C., the insulation of the first to sixth layers- In each of the steps of forming the wiring circuit composite layer, the heating temperature for main curing the resin film is (T + 30) ° C. or higher and (T + 80) ° C. or lower, and the first layer of insulation in the obtained multilayer printed wiring board is insulated. When the average thermal expansion coefficient of the layer is 25 ° C or higher and 150 ° C or lower is CTE _1, and the average thermal expansion coefficient of the fifth insulating layer of the obtained multilayer printed wiring board is 25 ° C or higher and 150 ° C or lower is CTE _5. , The _{ratio of CTE 1} to CTE ₅ is 0.75 or more. A method for manufacturing a multilayer printed wiring board having a thickness of 1.4 or less is provided.

In a specific aspect of the method for manufacturing a multilayer printed wiring board according to the present invention, _{the absolute value of the difference between the CTE 1} and the CTE ₅ is set to 7 ppm / ° C. or less.

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

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

In certain aspects of the method for manufacturing a multilayer printed wiring board according to the present invention, the thermosetting compound comprises an epoxy compound.

According to a broad aspect of the present invention, it contains a thermosetting compound and an inorganic filler, has an exothermic peak top temperature of 130 ° C. or higher and 200 ° C. or lower in measurement with a differential scanning calorimeter, and has a heat generation peak top temperature of 130 ° C. or higher. Of the heat generation peaks having a heat generation peak top temperature of 200 ° C. or lower, the peak temperature of the heat generation peak having the maximum peak height is set to T ° C., and 25 of the cured resin film cured at (T + 50) ° C. for 1.5 hours. _{The average thermal expansion coefficient of CTE 1.5 h} is defined as CTE 1.5 h or more and 150 ° C or lower, and the average thermal expansion coefficient of 25 ° C or higher and 150 ° C or lower of the cured resin film cured at (T + 50) ° C for 7.5 hours is CTE _{7. A} resin film is provided in which the ratio of CTE _7.5h to CTE _{1.5h is 0.75 or more and 1.4 or less at 5h.}

In a specific aspect of the resin film according to the present invention, _{the absolute value of the difference between the CTE 1.5h} and the CTE _7.5h is 7 ppm / ° C. or less.

In certain aspects of the resin film according to the present invention, the thermosetting compound comprises an epoxy compound.

The resin film according to the present invention is suitably used for forming an insulating layer by main curing the resin film by heating at 190 ° C. or higher and 200 ° C. or lower.

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-layer insulation-wiring circuit composite layer composed of a first-layer insulating layer and a first-layer wiring circuit layer, and a second-layer insulating layer on the circuit board. And the second layer of insulation-wiring circuit composed of the second layer of wiring circuit layer, and the third layer of insulation-wiring circuit composed of the third layer of insulation layer and the third layer of wiring circuit layer. It is composed of a 4th insulation-wiring circuit composite layer composed of a composite layer, a 4th insulating layer and a 4th wiring circuit layer, a 5th insulating layer and a 5th wiring circuit layer. It has at least a fifth layer of insulation-wiring circuit composite layer and a sixth layer of insulation-wiring circuit composite layer composed of a sixth layer of insulation layer and a sixth layer of wiring circuit layer, and the resin. The film contains a thermosetting compound and an inorganic filler, and the resin film has a heat generation peak top temperature of 130 ° C. or higher and 200 ° C. or lower as measured by a differential scanning calorimeter, and is the first layer of insulation. When the average thermal expansion coefficient of the layer from 25 ° C to 150 ° C is set to CTE ₁ and the average thermal expansion coefficient of the fifth insulating layer from 25 ° C to 150 ° C is set to CTE ₅ , the average thermal expansion coefficient of the CTE ₁ is relative to _{CTE 5.} A multilayer printed wiring board having a ratio of 0.75 or more and 1.4 or less is provided.

In a particular aspect of the multilayer printed wiring board according to the present invention, _{the absolute value of the difference between the CTE 1} and the CTE ₅ is 7 ppm / ° C. 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, and a resin film is used. This is a method for manufacturing a multilayer printed wiring board that forms a plurality of insulating layers. In the method for manufacturing a multilayer printed wiring board according to the present invention, a first insulating layer is formed on a circuit board by using a resin film, and the first wiring circuit layer is formed on the first insulating layer. The step of forming the first layer of the insulation-wiring circuit composite layer is provided. In the method for manufacturing a multilayer printed wiring board according to the present invention, a second insulating layer is formed on the first insulating-wiring circuit composite layer by using a resin film, and the second insulating layer is formed. A second layer of the wiring circuit layer is formed in the above, and a step of forming the second layer of the insulation-wiring circuit composite layer is provided. In the method for manufacturing a multilayer printed wiring board according to the present invention, a third insulating layer is formed on the second insulating-wiring circuit composite layer by using a resin film, and the third insulating layer is formed. A third layer of the wiring circuit layer is formed in the above, and a step of forming the third layer of the insulation-wiring circuit composite layer is provided. In the method for manufacturing a multilayer printed wiring board according to the present invention, a fourth insulating layer is formed on the third insulating-wiring circuit composite layer by using a resin film, and the fourth insulating layer is formed. A step of forming a fourth layer of the wiring circuit layer and forming the fourth layer of the insulation-wiring circuit composite layer is provided. In the method for manufacturing a multilayer printed wiring board according to the present invention, a fifth insulating layer is formed on the fourth insulating-wiring circuit composite layer by using a resin film, and the fifth insulating layer is formed. A step of forming the fifth layer of the wiring circuit layer and forming the fifth layer of the insulation-wiring circuit composite layer is provided. In the method for manufacturing a multilayer printed wiring board according to the present invention, a sixth insulating layer is formed on the fifth insulating-wiring circuit composite layer by using a resin film, and the sixth insulating layer is formed. A step of forming the sixth layer of the wiring circuit layer and forming the sixth layer of the insulation-wiring circuit composite layer is provided. In the method for producing a multilayer printed wiring board according to the present invention, the resin film contains 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 a heat generation peak top temperature of 130 ° C. or higher and 200 ° C. or lower as measured by a differential scanning calorimeter. In the method for manufacturing a multilayer printed wiring board according to the present invention, among the heat generation peaks having a heat generation peak top temperature of 130 ° C. or higher and 200 ° C. or lower, the peak temperature of the heat generation peak having the maximum peak height is set to 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 insulation-wiring circuit composite layer of the first layer to the sixth layer, the heating temperature for main curing the resin film is (1). T + 30) ° C. or higher (T + 80) ° C. or lower. The average coefficient of thermal expansion of the first insulating layer in the obtained multilayer printed wiring board is 25 ° C or higher and 150 ° C or lower as CTE _1, and the average thermal expansion coefficient of the fifth insulating layer in the obtained multilayer printed wiring board is 25 ° C or higher and 150 ° C or lower. Let the average coefficient of thermal expansion of be CTE ₅ . In the method for manufacturing a multilayer printed wiring board according to the present invention, the _{ratio of CTE 1} to CTE _{5 is set} to 0.75 or more and 1.4 or less. Since the above-mentioned configuration is provided in the method for manufacturing a multilayer printed wiring board according to the present invention, it is possible to prevent cracks or cracks in the insulating layer around the via hole and the wiring circuit layer in the via portion, and the connection reliability can be prevented. It is possible to obtain a multi-layer printed wiring board that can enhance.

The resin film according to the present invention contains a thermosetting compound and an inorganic filler, and has a heat generation peak top temperature of 130 ° C. or higher and 200 ° C. or lower as measured by a differential scanning calorimeter. In the resin film according to the present invention, among the heat generation peaks having a heat generation peak top temperature of 130 ° C. or higher and 200 ° C. or lower, the peak temperature of the heat generation peak having the maximum peak height is defined as T ° C. In the resin film according to the present invention, the thermal expansion coefficient of the cured product of the resin film cured at (T + 50) ° C. for 1.5 hours is set to CTE _1.5h, and the resin film cured at (T + 50) ° C. for 7.5 hours. When the thermal expansion coefficient of the cured product is CTE _7.5h , the _{ratio of CTE 7.5h} to CTE _1.5h is 0.75 or more and 1.4 or less. Since the resin film according to the present invention has the above configuration, it is possible to prevent cracks or cracks in the insulating layer around the via hole and the wiring circuit layer in the via portion, and it is possible to improve the connection reliability. ..

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 arranged 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 layers of insulation-wiring circuit composite layers. A first-layer insulation-wiring circuit composite layer composed of a first-layer insulating layer and a first-layer wiring circuit layer on the circuit board. A second insulating-wiring circuit composite layer composed of a second insulating layer and a second wiring circuit layer. A third-layer insulation-wiring circuit composite layer composed of a third-layer insulating layer and a third-layer wiring circuit layer. A fourth insulating-wiring circuit composite layer composed of a fourth insulating layer and a fourth wiring circuit layer. A fifth insulating-wiring circuit composite layer composed of a fifth insulating layer and a fifth wiring circuit layer. A sixth insulating-wiring circuit composite layer composed of 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 at 130 ° C. or higher and 200 ° C. or lower as measured by a differential scanning calorimeter. Has a peak top temperature. In the multilayer printed wiring board according to the present invention, the average coefficient of thermal expansion of the first insulating layer of 25 ° C. or higher and 150 ° C. or lower is set to CTE _1, and the average thermal expansion of the fifth insulating layer of 25 ° C. or higher and 150 ° C. or lower is set. When the coefficient is CTE ₅ , the _{ratio of CTE 1} to CTE ₅ is 0.75 or more and 1.4 or less. Since the multilayer printed wiring board according to the present invention has the above configuration, it is possible to prevent cracks or cracks in the insulating layer around the via hole and the wiring circuit layer in the via portion, and to improve the connection reliability. Can be done.

FIG. 1 is a cross-sectional view schematically showing a multilayer printed wiring board using a resin film according to an embodiment of the present invention. 2 (a) to 2 (d) are cross-sectional views for explaining a method of obtaining the multilayer printed wiring board shown in FIG. 1. 3A to 3C are cross-sectional views for explaining a method of obtaining the multilayer printed wiring board shown in FIG. 1. 4 (a) to 4 (f) are cross-sectional views for explaining a method of obtaining the multilayer printed wiring board shown in FIG. 1.

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, and a resin film is used. This is a method for manufacturing a multilayer printed wiring board that forms a plurality of insulating layers. In the method for manufacturing a multilayer printed wiring board according to the present invention, a first insulating layer is formed on a circuit board by using a resin film, and the first wiring circuit layer is formed on the first insulating layer. The step of forming the first layer of the insulation-wiring circuit composite layer is provided. In the method for manufacturing a multilayer printed wiring board according to the present invention, a second insulating layer is formed on the first insulating-wiring circuit composite layer by using a resin film, and the second insulating layer is formed. A second layer of the wiring circuit layer is formed in the above, and a step of forming the second layer of the insulation-wiring circuit composite layer is provided. In the method for manufacturing a multilayer printed wiring board according to the present invention, a third insulating layer is formed on the second insulating-wiring circuit composite layer by using a resin film, and the third insulating layer is formed. A third layer of the wiring circuit layer is formed in the above, and a step of forming the third layer of the insulation-wiring circuit composite layer is provided. In the method for manufacturing a multilayer printed wiring board according to the present invention, a fourth insulating layer is formed on the third insulating-wiring circuit composite layer by using a resin film, and the fourth insulating layer is formed. A step of forming a fourth layer of the wiring circuit layer and forming the fourth layer of the insulation-wiring circuit composite layer is provided. In the method for manufacturing a multilayer printed wiring board according to the present invention, a fifth insulating layer is formed on the fourth insulating-wiring circuit composite layer by using a resin film, and the fifth insulating layer is formed. A step of forming the fifth layer of the wiring circuit layer and forming the fifth layer of the insulation-wiring circuit composite layer is provided. In the method for manufacturing a multilayer printed wiring board according to the present invention, a sixth insulating layer is formed on the fifth insulating-wiring circuit composite layer by using a resin film, and the sixth insulating layer is formed. A step of forming the sixth layer of the wiring circuit layer and forming the sixth layer of the insulation-wiring circuit composite layer is provided. In the method for producing a multilayer printed wiring board according to the present invention, the resin film contains 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 a heat generation peak top temperature of 130 ° C. or higher and 200 ° C. or lower as measured by a differential scanning calorimeter. In the method for manufacturing a multilayer printed wiring board according to the present invention, when the peak temperature of the heat generation peak having the maximum peak height is set to T ° C. among the heat generation peaks having the heat generation peak top temperature of 130 ° C. or higher and 200 ° C. or lower. In each of the steps of forming the insulation-wiring circuit composite layer of the first to sixth layers, the heating temperature for main curing the resin film is (T + 30) ° C. or higher and (T + 80) ° C. or lower. The average coefficient of thermal expansion of the first insulating layer in the obtained multilayer printed wiring board is 25 ° C or higher and 150 ° C or lower as CTE _1, and the average thermal expansion coefficient of the fifth insulating layer in the obtained multilayer printed wiring board is 25 ° C or higher and 150 ° C or lower. Let the average coefficient of thermal expansion of be CTE ₅ . In the method for manufacturing a multilayer printed wiring board according to the present invention, the _{ratio of CTE 1} to CTE _{5 is set} to 0.75 or more and 1.4 or less.

Since the above-mentioned configuration is provided in the method for manufacturing a multilayer printed wiring board according to the present invention, it is possible to prevent cracks or cracks in the insulating layer around the via hole and the wiring circuit layer in the via portion, and the connection reliability can be prevented. It is possible to obtain a multi-layer printed wiring board that can enhance.

Since the above-mentioned configuration is provided in the method for manufacturing a multilayer printed wiring board according to the present invention, it is possible to prevent cracks or cracks in the insulating layer and the wiring circuit layer in the portion other than the vicinity of the via hole. That is, in the method for manufacturing a multilayer printed wiring board according to the present invention, it is possible to prevent the occurrence of cracks or cracks in the entire insulating layer and the entire wiring circuit layer.

The resin film according to the present invention contains a thermosetting compound and an inorganic filler, and has a heat generation peak top temperature of 130 ° C. or higher and 200 ° C. or lower as measured by a differential scanning calorimeter. In the resin film according to the present invention, among the heat generation peaks having a heat generation peak top temperature of 130 ° C. or higher and 200 ° C. or lower, the peak temperature of the heat generation peak having the maximum peak height is defined as T ° C. In the resin film according to the present invention, the average thermal expansion coefficient of the cured product of the resin film cured at (T + 50) ° C. for 1.5 hours is 25 ° C. or higher and 150 ° C. or lower as CTE _1.5h, and 7 at (T + 50) ° C. The average thermal expansion coefficient of the cured product of the resin film cured for 5. hours at 25 ° C. or higher and 150 ° C. or lower is _defined as CTE 7.5h. In the resin film according to the present invention, the _{ratio of CTE 7.5h} to CTE _1.5h is 0.75 or more and 1.4 or less.

Since the resin film according to the present invention has the above configuration, it is possible to prevent cracks or cracks in the insulating layer around the via hole and the wiring circuit layer in the via portion, and it is possible to improve the connection reliability. ..

Since the resin film according to the present invention has the above-mentioned configuration, it is possible to prevent cracks or cracks in the insulating layer and the wiring circuit layer in the portion other than the vicinity of the via hole. That is, the resin film according to the present invention can prevent cracks or cracks in the entire insulating layer and the entire wiring circuit layer.

The resin film according to the present invention is preferably used for forming an insulating layer of 6 or more in a multilayer printed wiring board. The resin film according to the present invention can also be used to form an insulating layer of 5 or less in a multilayer printed wiring board. Even if the resin film according to the present invention is used to form an insulating layer of 5 or less, it is possible to prevent cracks or cracks in the insulating layer around the via hole and the wiring circuit layer in the via portion, and the connection reliability is high. Can be enhanced.

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 arranged 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 layers of insulation-wiring circuit composite layers. A first-layer insulation-wiring circuit composite layer composed of a first-layer insulating layer and a first-layer wiring circuit layer on the circuit board. A second insulating-wiring circuit composite layer composed of a second insulating layer and a second wiring circuit layer. A third-layer insulation-wiring circuit composite layer composed of a third-layer insulating layer and a third-layer wiring circuit layer. A fourth insulating-wiring circuit composite layer composed of a fourth insulating layer and a fourth wiring circuit layer. A fifth insulating-wiring circuit composite layer composed of a fifth insulating layer and a fifth wiring circuit layer. A sixth insulating-wiring circuit composite layer composed of 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 at 130 ° C. or higher and 200 ° C. or lower as measured by a differential scanning calorimeter. Has a peak top temperature. In the multilayer printed wiring board according to the present invention, the average coefficient of thermal expansion of the first insulating layer of 25 ° C. or higher and 150 ° C. or lower is set to CTE _1, and the average thermal expansion of the fifth insulating layer of 25 ° C. or higher and 150 ° C. or lower is set. When the coefficient is CTE ₅ , the _{ratio of CTE 1} to CTE ₅ is 0.75 or more and 1.4 or less.

Since the multilayer printed wiring board according to the present invention has the above configuration, it is possible to prevent cracks or cracks in the insulating layer around the via hole and the wiring circuit layer in the via portion, and to improve the connection reliability. Can be done.

Since the multilayer printed wiring board according to the present invention has the above configuration, it is possible to prevent cracks or cracks in the insulating layer and the wiring circuit layer in the portion other than the vicinity of the via hole. That is, in the multilayer printed wiring board according to the present invention, it is possible to prevent the occurrence of cracks or cracks in the entire insulating layer and the entire wiring circuit layer.

In the conventional method for manufacturing a multilayer printed wiring board, a resin film, and a multilayer printed wiring board, the dimensional stability of the insulating layer is formed by an insulating layer formed by being laminated at an early stage and an insulating layer formed by being laminated at a later stage. Changes. For this reason, stress may be concentrated on the insulating layer due to temperature changes during the reflow process and in reliability tests such as the thermal cycle, and cracks or cracks may occur in the insulating layer and the wiring circuit layer. In this case, stress is particularly likely to be concentrated on the via hole portion, cracks or cracks are likely to occur in the insulating layer around the via hole, and cracks or cracks are likely to occur in the wiring circuit layer of the via portion. Further, when the stack via is formed, cracks or cracks are more likely to occur in the insulating layer around the via hole and the wiring circuit layer of the stack via portion. On the other hand, in the method for manufacturing a multilayer printed wiring board, a resin film, and a multilayer printed wiring board according to the present invention, since a specific resin film is used, the dimensional stability of the insulating layer is unlikely to change, and the area around the via hole is not easily changed. It is possible to prevent the occurrence of cracks or cracks in the insulating layer and the wiring circuit layer of the via portion, and it is possible to improve the connection reliability. In the method for manufacturing a multilayer printed wiring board, a resin film, and a multilayer printed wiring board according to the present invention, even when stack vias are formed, cracks or cracks occur in the insulating layer around the via hole and the wiring circuit layer in the via portion. Can be prevented.

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

Prepare a differential scanning calorimetry device (for example, "Q2000" manufactured by TA Instrument Co., Ltd.). Take 8 mg of resin film on a special aluminum pan and cover it with a special jig. This dedicated aluminum pan and an empty aluminum pan (reference) are installed in the heating unit and heated from -30 ° C to 250 ° C at a heating rate of 3 ° C / min under a nitrogen atmosphere, and reverse heat flow and non-reverse. Observe the heat flow. The heat generation peak observed in the non-reverse heat flow is defined as the heat generation peak of the resin film.

The resin film has a heat generation peak top temperature of 130 ° C. or higher and 200 ° C. or lower as measured by a differential scanning calorimeter. If the exothermic peak top temperature is less than 130 ° C., the storage stability of the resin film may deteriorate. If the exothermic peak top temperature exceeds 200 ° C., the temperature variation of the drying furnace may become large, and it may be difficult to manufacture the 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, preferably 170 ° C. or lower.

Among the exothermic peaks having the exothermic peak top temperature at 130 ° C. or higher 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 at 130 ° C. or higher and 200 ° C. or lower in the measurement of the differential scanning calorimeter. When there is one exothermic peak having the exothermic peak top temperature at 130 ° C. or higher and 200 ° C. or less, 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 at 130 ° C. or higher and 200 ° C. or less, the peak temperature T of the exothermic peak having the maximum peak height is the maximum peak height of the exothermic peaks. It 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 higher and 200 ° C. or lower. If the peak temperature T is less 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, it is possible to suppress variations in curing and residual curing of the resin film in the manufacturing process as compared with the case where the temperature 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 step (SAP step) is preferably 200 nm or less. The degree of curing of the resin film (semi-cured product) after the roughening treatment has a great influence on the control of the surface roughness of the surface of the resin film (semi-cured product) after the roughening treatment. The peak temperature T is preferably in the above-mentioned temperature range from the viewpoint of controlling the degree of curing of the semi-cured product before the roughening treatment and sufficiently curing the semi-cured product in the final cure after the roughening treatment.

The temperature of 25 ° C. or higher and 150 ° C. or lower of the cured product of the resin film according to the present invention, the multilayer printed wiring board obtained by the method for manufacturing the multilayer printed wiring board according to the present invention, and the insulating layer of the multilayer printed wiring board according to the present invention. The average coefficient of thermal expansion (coefficient of linear expansion) can be measured as follows.

Using a thermomechanical analyzer (for example, "EXSTAR TMA / SS6100" manufactured by SII Nanotechnology Co., Ltd.), a cured product of a resin film or an insulating layer under the conditions of a tensile load of 33 mN and a heating rate of 5 ° C./min. The average coefficient of thermal expansion (ppm / ° C.) of 25 ° C. or higher and 150 ° C. or lower is calculated.

The average thermal expansion coefficient of the insulating layer of the multilayer printed wiring board obtained by the method for manufacturing the multilayer printed wiring board according to the present invention and the insulating layer of the multilayer printed wiring board according to the present invention is 25 ° C. or higher and 150 ° C. or lower. The same resin film as the resin film used for the plate may be cured to obtain the cured resin film (insulating layer).

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 average coefficient of thermal expansion of the first insulating layer at 25 ° C. or higher and 150 ° C. or lower is CTE _1. The average coefficient of thermal expansion of the fifth insulating layer at 25 ° C. or higher and 150 ° C. or lower is defined as CTE ₅ . When 10 or more insulation-wiring circuit composite layers are formed, the average coefficient of thermal expansion of the 10th insulation layer at 25 ° C. or higher and 150 ° C. or lower is defined as CTE ₁₀ . It is preferable that the first insulating layer, the fifth insulating layer, and the tenth insulating layer are each the insulating layer after the main curing. The insulating layer after the main curing may be pre-cured before the main curing. The insulating layer after the main curing is preferably an insulating layer that has been finally cured after the pre-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 CTE ₅ of the _{CTE 1 (CTE 1 / CTE 5} ) is 0.75 to 1.4 be. When the above ratio (CTE ₁ / CTE ₅ ) is less than 0.75, cracks or cracks in the insulating layer are likely to occur. If the above ratio (CTE ₁ / CTE ₅ ) exceeds 1.4, the resin component may volatilize due to heating after curing, and as a result, the flexibility of the resin film and the insulating layer decreases, and insulation is performed. The film may crack or chip.

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 CTE ₅ of the _{CTE 1 (CTE 1 / CTE 5} ) is preferably 0.76 or more, more preferably Is 0.8 or more, preferably 1.2 or less, and more preferably 1.1 or less. When the ratio (CTE ₁ / CTE ₅ ) is equal to or higher than the lower limit and lower than the upper limit, cracks or cracks in the insulating layer around the via hole and the wiring circuit layer in the via portion can be more effectively suppressed.

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 _{CTE 10} of the _{CTE 1 (CTE 1 / CTE 10} ) is preferably 0.7 or more, more preferably Is 0.75 or more, preferably 1.2 or less, and more preferably 1.1 or less. When the ratio (CTE ₁ / CTE ₁₀ ) is equal to or higher than the lower limit and lower than the upper limit, it is possible to more effectively suppress the occurrence of cracks or cracks in the insulating layer around the via hole and the wiring circuit layer in the via portion. ..

From the viewpoint of effectively suppressing the occurrence of cracks or cracks in the insulating layer around the via hole and the wiring circuit layer in the via portion, _{the absolute value of the difference between the above CTE 1} and the above CTE ₅ is preferably 7 ppm / ° C. or less. It is preferably 5 ppm / ° C. or lower.

From the viewpoint of effectively suppressing the occurrence of cracks or cracks in the insulating layer around the via hole and the wiring circuit layer in the via portion, _{the absolute value of the difference between the above CTE 1} and the above CTE ₁₀ is preferably 7 ppm / ° C. or less. It is preferably 5 ppm / ° C. or lower.

The coefficient of linear expansion of the first, fifth, and tenth insulating layers (CTE ₁ , CTE _5, and CTE ₁₀ above) is measured using the insulating layer provided on the multilayer printed wiring board. That is difficult. Therefore, the above-mentioned CTE ₁ , the above-mentioned CTE ₅ and the above-mentioned CTE ₁₀ are measured as follows.

Prepare a resin film having the same composition as the resin film used in manufacturing the multilayer printed wiring board. A wire of a cured product (insulating layer) obtained by curing the resin film at a heating temperature and heating time equivalent to the heating temperature and time of the first insulating layer in the manufacturing process of the multilayer printed wiring board. The expansion coefficient is measured and set to CTE ₁ . A wire of a cured product (insulating layer) obtained by curing the resin film at a heating temperature and heating time equivalent to the heating temperature and time of the fifth insulating layer in the manufacturing process of the multilayer printed wiring board. The expansion coefficient is measured and set to CTE ₅ . A wire of a cured product (insulating layer) obtained by curing the resin film at a heating temperature and heating time equivalent to the heating temperature and time of the tenth insulating layer in the manufacturing process of the multilayer printed wiring board. The expansion coefficient is measured and used as CTE ₁₀ . In the manufacturing process of the multilayer printed wiring board, the heating is performed for a long time in the order of the first insulating layer> the fifth insulating layer> the tenth insulating layer.

From the viewpoint of more effectively suppressing the occurrence of cracks or cracks in the insulating layer around the via hole and the wiring circuit layer in the via portion, the CTE ₁ is preferably 17 ppm / ° C. or higher, preferably 33 ppm / ° C. or lower, more preferably. Is 25 ppm / ° C or less.

In the resin film according to the present invention, the average coefficient of thermal expansion of the cured product of the resin film cured at (T + 50) ° C. for 1.5 hours is set to CTE _1.5h at 25 ° C. or higher and 150 ° C. or lower. In the resin film according to the present invention, the average coefficient of thermal expansion of the cured product of the resin film cured at (T + 50) ° C. for 7.5 hours is set to CTE _7.5h at 25 ° C. or higher and 150 ° C. or lower. In the resin film according to the present invention, the average coefficient of thermal expansion of the cured product of the resin film cured at (T + 50) ° C. for 15 hours is 25 ° C. or higher and 150 ° C. or lower as CTE _15h .

The resin film may be heated at a temperature lower than the peak temperature T before the measurement of the average coefficient of thermal expansion. For example, when the peak temperature T of the resin film is 145 ° C., the resin film may be heated at 130 ° C. for 60 minutes before measuring the average coefficient of thermal expansion. Even if the resin film is heated at a temperature _lower than the peak temperature T, the measurement results of the _{CTE 1.5h} , the CTE 7.5h, and the CTE _{15h are unlikely to change.}

The resin film according to the present invention, the ratio above _{CTE 1.5 h} the _{CTE 7.5h (CTE 7.5h / CTE 1.5h} ) is 0.75 to 1.4. When the above ratio (CTE _7.5h / CTE _1.5h ) is less than 0.7 or more than 1.4, the insulating layer and the wiring circuit layer (particularly the insulating layer around the via hole, the wiring circuit layer of the via portion and the via portion). Cracks or cracks may occur at the base of the beer.

The resin film according to the present invention, the _{CTE 7.5 h} ratio above _{CTE 1.5 h} of _(CTE 7.5h _/ CTE _1.5h) is preferably 0.76 or more, more preferably 0.8 or more, preferably It is 1.2 or less, more preferably 1.1 or less. When the above ratio (CTE _7.5h / CTE _1.5h ) is equal to or higher than the lower limit and lower than the upper limit, cracks or cracks in the insulating layer around the via hole and the wiring circuit layer in the via portion are more effectively suppressed. be able to.

The resin film according to the present invention, the ratio above _{CTE 1.5 h} the _{CTE 15h (CTE 15h / CTE 1.5h} ) is preferably 0.7 or more, more preferably 0.75 or more, preferably 1.2 Below, it is more preferably 1.1 or less. When the above ratio (CTE _15h / CTE _1.5h ) is equal to or higher than the lower limit and lower than the upper limit, the occurrence of cracks or cracks in the insulating layer around the via hole and the wiring circuit layer in the via portion is further effectively suppressed. Can be done.

From the viewpoint of effectively suppressing the occurrence of cracks or cracks in the insulating layer around the via hole and the wiring circuit layer in the via portion, the absolute value of the difference between the _{CTE 1.5h} and the CTE _{7.5h is preferably 7 ppm /.} It is ℃ or less, more preferably 5 ppm / ℃ or less.

From the viewpoint of effectively suppressing the occurrence of cracks or cracks in the insulating layer around the via hole and the wiring circuit layer in the via portion, _{the absolute value of the difference between the above CTE 1.5h} and the above CTE _15h is preferably 8 ppm / ° C. or less. , More preferably 6 ppm / ° C. or less.

From the viewpoint of more effectively suppressing the occurrence of cracks or cracks in the insulating layer around the via hole and the wiring circuit layer in the via portion, the CTE _1.5h is preferably 17 ppm / ° C. or higher, preferably 33 ppm / ° C. or lower. More preferably, it is 25 ppm / ° C. or lower.

In the resin film according to the present invention, the average coefficient of thermal expansion of the cured product of the resin film cured at (T + 30) ° C. or higher (T + 80) ° C. for 1.5 hours is CTE ' _1.5h . do. In the resin film according to the present invention, the average coefficient of thermal expansion of the cured product of the resin film cured at (T + 30) ° C. or higher (T + 80) ° C. for 7.5 hours is CTE ' _7.5h . do. In the resin film according to the present invention, the average coefficient of thermal expansion of the cured product of the resin film cured at (T + 30) ° C. or higher (T + 80) ° C. for 15 hours is 25 ° C. or higher and 150 ° C. or lower as CTE _'15 h.

The resin film according to the present invention, the ratio of _{1.5 h} 'above the CTE of _{7.5 h'} above _{CTE (CTE '7.5h / CTE'} 1.5h) is preferably 0.75 or more, more preferably 0. It is 76 or more, more preferably 0.8 or more, preferably 1.4 or less, more preferably 1.2 or less, still more preferably 1.1 or less. When the ratio _{(CTE '7.5h / CTE' 1.5h} ) is below the lower limit or more and the upper limit, effectively suppressing the occurrence cracking or breakage of the wiring circuit layer of the insulating layer and the via portion around the via hole be able to.

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

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 as a resin film used for a multilayer printed wiring board.

The resin film is preferably a B stage film.

(Manufacturing method of multilayer printed wiring board and multilayer printed wiring board)
Hereinafter, the present invention will be clarified by explaining 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 an 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 has a first layer of insulating layer 13, a first layer of wiring circuit layer 14, a second layer of insulating layer 15, a second layer of wiring circuit layer 16, and a third layer of insulation. Layer 17, third layer wiring circuit layer 18, fourth layer insulating layer 19, fourth layer wiring circuit layer 20, fifth layer insulating layer 21, fifth layer wiring circuit layer 22 And a sixth layer of the insulating layer 23 and a sixth layer of the wiring circuit layer 24. A circuit board is composed of a board 11 and a wiring circuit layer 12. The first insulating layer 13 and the first wiring circuit layer 14 form 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 form a third insulating-wiring circuit composite layer. The fourth insulating layer 19 and the fourth wiring circuit layer 20 form a fourth insulating-wiring circuit composite layer. The fifth insulating layer 21 and the fifth wiring circuit layer 22 form a fifth insulating-wiring circuit composite layer. The sixth insulating layer 23 and the sixth wiring circuit layer 24 form a sixth insulating-wiring circuit composite layer.

The substrate 11 has a hole 11a. 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 arranged on the surface of the substrate 11. Further, the wiring circuit layer 12 is partially arranged on the surfaces on both sides of the substrate 11. The wiring circuit layer 12 is also arranged in the hole 11a of the substrate 11. The wiring circuit layer 12 portion arranged in the hole 11a conducts the wiring circuit layer 12 portion located on the surface on both sides (the lower side is not shown). 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 holes that are open so that the surface of the wiring circuit layer 12 is partially exposed. The hole is also called a beer hole.

The wiring circuit layer 14 is arranged on the surface of the insulating layer 13. The insulating layer 13 and the wiring circuit layer 14 form a first insulating-wiring circuit composite layer. The wiring circuit layer 14 is partially arranged 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 portion arranged in the hole. The wiring circuit layer 12 and the wiring circuit layer 14 are electrically connected to each other.

The insulating layer 15 is laminated on the surface of the wiring circuit layer 14. The insulating layer 15 has holes that are open 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 form a second insulating-wiring circuit composite layer. The wiring circuit layer 16 is partially arranged 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 portion arranged in the hole. The wiring circuit layer 14 and the wiring circuit layer 16 are electrically connected to each other.

The insulating layer 17 is laminated on the surface of the wiring circuit layer 16. The insulating layer 17 has holes that are open so that the surface of the wiring circuit layer 16 is partially exposed.

The wiring circuit layer 18 is arranged 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 portion arranged in the hole. The wiring circuit layer 16 and the wiring circuit layer 18 are electrically connected to each other.

Similarly, the fourth to sixth layers of the insulation-wiring circuit composite layer are formed.

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

Further, a solder resist film or the like may be formed on the outermost layer.

Further, the circuit board itself may have an insulation-wiring circuit composite layer of an insulating layer and a wiring circuit layer. The circuit board before forming the insulating layer using the specific resin film may be a circuit board having an insulation-wiring circuit composite layer of the insulating layer and the wiring circuit layer. The first insulating-wiring circuit composite layer formed of 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 by using a specific resin film. The first insulating-wiring circuit composite layer formed using a specific resin film is used as the first insulating-wiring circuit composite layer.

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

Next, a method for obtaining the multilayer printed wiring board 1 shown in FIG. 1 will be described with reference to FIGS. 2 (a) to 2 (d), FIGS. 3 (a) to 3 (c) and FIGS. 4 (a) to 4 (f). This will be described in detail.

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

A resin film is laminated on the surface of the wiring circuit layer 12 of the circuit board, and then cured by heating to form the 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. 2 (c)). Examples of the laser include a UV laser, a carbon dioxide gas laser, an excimer laser and the like.

Next, the inside of the hole of the insulating layer 13B is desmear-treated to obtain the insulating layer 13 whose inside of the hole is desmear-treated (FIG. 2 (d)). The desmear treatment cleans the inside of the hole and removes the smear. 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 treatment liquid for the desmear treatment and the roughening treatment for increasing the surface roughness of the insulating layer, and the desmear treatment and the roughening treatment for increasing the surface roughness of the insulating layer are preferable. It is preferable that the above is performed at the same time.

Further, after the desmear treatment, 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 treatment for cleaning the inside of the hole and the roughening treatment for roughening the surface of the wiring circuit layer 12 may be performed as separate steps. The roughness treatment after the desmear treatment increases the roughness of the roughened surface of the wiring circuit layer 12. 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 becomes large. Therefore, the continuity reliability 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 layer 12 and the wiring circuit layer 14.

Next, it is preferable to perform electroless plating on the surface of the insulating layer 13. As a result, 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 does not necessarily have to be formed. By forming the resist pattern 51, a conductor layer (wiring circuit layer) can be selectively formed on the surface of the insulating layer 13 by performing electroplating or the like on a portion not covered by the resist pattern 51.

Next, by performing electroplating or the like, the wiring circuit layer 14 is formed on the surface of the insulating layer 13 and in the hole of the insulating layer 13 (FIG. 3 (b)). By connecting the surface of the wiring circuit layer 12 that has been roughened after the desmear treatment and the surface of the wiring circuit layer 14, the wiring circuit layer 12 and the wiring circuit layer 14 are made conductive.

Next, the resist pattern 51 is peeled off with an alkaline aqueous solution or the like containing sodium hydroxide or the like and removed (FIG. 3 (c)). 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). In this way, the first insulating-wiring circuit composite layer composed of the first insulating layer 13 and the first wiring circuit layer 14 is formed. When forming the first insulating-wiring circuit composite layer, the resin film is heated at a heating temperature of (T + 30) ° C. or higher and (T + 80) ° C. or lower in order to main 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, a resin film is laminated on the surface of the first insulating-wiring circuit composite layer, and then cured 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. 4 (b)).

Next, the inside of the hole of the insulating layer 15B is desmear-treated to obtain the insulating layer 15 whose inside of the hole is desmear-treated (FIG. 4 (c)). The desmear treatment cleans the inside of the hole and removes the smear. When the desmear treatment is performed, 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 treatment liquid for the desmear treatment and the roughening treatment for increasing the surface roughness of the insulating layer, and the desmear treatment and the roughening treatment for increasing the surface roughness of the insulating layer are preferable. It is preferable that the above is performed at the same time.

Further, after the desmear treatment, 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 has been roughened can be obtained.

Next, it is preferable to perform electroless plating on the surface of the insulating layer 15. As a result, 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. 4 (d)).

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

Next, the resist pattern 52 is peeled off with an alkaline aqueous solution or the like containing sodium hydroxide or the like and removed (FIG. 4 (f)). In this way, the second insulating-wiring circuit composite layer composed of the second insulating layer 15 and the second wiring circuit layer 16 is formed. When forming the second insulating-wiring circuit composite layer, the resin film is heated at a heating temperature of (T + 30) ° C. or higher and (T + 80) ° C. or lower in order to actually 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.

The above steps are repeated to form the third and subsequent insulation-wiring circuit composite layers. In this way, the multilayer printed wiring board 1 can be obtained. In the method for manufacturing the multilayer printed wiring board 1, when the second insulating layer is formed, the first insulating layer is exposed to a curing 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 curing 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 curing environment for forming the fourth insulating layer. Be exposed to. When forming the fifth insulating layer, each of the first insulating layer, the second insulating layer, the third insulating layer, and the fourth insulating layer is the fifth insulating layer. Is exposed to a curing environment to form. When forming the sixth insulating layer, each of the first insulating layer, the second insulating layer, the third insulating layer, the fourth insulating layer, and the fifth insulating layer is formed. , Is exposed to a curing environment for forming the sixth insulating layer. The first insulating layer is exposed to a curing environment depending on the number of layers of the insulating layer to be formed. The second insulating layer is exposed to a curing environment as many times as the number of layers of the insulating layer to be formed-1. The third insulating layer is exposed to a curing environment as many times as the number of layers of the insulating layer formed-2. The fourth insulating layer is exposed to a curing environment as many times as the number of layers of the insulating layer formed-3. The fifth insulating layer is exposed to a curing environment as many times as the number of layers of the insulating layer to be formed-4. The sixth insulating layer is exposed to a curing environment as many times as the number of layers of the insulating layer to be formed −5. The nth insulating layer is exposed to the curing environment by the number of layers of the insulating layer formed − (n-1). By _{setting the ratio of CTE 1} to CTE ₅ to 0.75 or more and 1.4 or less, it is possible to obtain a multilayer printed wiring board 1 capable of preventing the occurrence of cracks or cracks in the insulating layer and the wiring circuit layer.

Like the method for manufacturing a printed wiring board described above, the method for manufacturing a multilayer printed wiring board according to the present invention forms a first insulating layer on a circuit board using a resin film, and the first layer is formed. A step of forming the first wiring circuit layer on the insulating layer of the above and forming the first insulating-wiring circuit composite layer is provided.

The resin film for forming the first insulating layer is laminated on the 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.

In the method for manufacturing a multilayer printed wiring board according to the present invention, a second insulating layer is formed on the first insulating-wiring circuit composite layer by using a resin film, and the second insulating layer is formed. A second layer of the wiring circuit layer is formed in the above, and a step of forming the second layer of the insulation-wiring circuit composite layer is provided.

In the method for manufacturing a multilayer printed wiring board according to the present invention, a third insulating layer is formed on the second insulating-wiring circuit composite layer by using a resin film, and the third insulating layer is formed. A third layer of the wiring circuit layer is formed in the above, and a step of forming the third layer of the insulation-wiring circuit composite layer is provided.

In the method for manufacturing a multilayer printed wiring board according to the present invention, a fourth insulating layer is formed on the third insulating-wiring circuit composite layer by using a resin film, and the fourth insulating layer is formed. A step of forming a fourth layer of the wiring circuit layer and forming the fourth layer of the insulation-wiring circuit composite layer is provided.

In the method for manufacturing a multilayer printed wiring board according to the present invention, a fifth insulating layer is formed on the fourth insulating-wiring circuit composite layer by using a resin film, and the fifth insulating layer is formed. A step of forming the fifth layer of the wiring circuit layer and forming the fifth layer of the insulation-wiring circuit composite layer is provided.

In the method for manufacturing a multilayer printed wiring board according to the present invention, a sixth insulating layer is formed on the fifth insulating-wiring circuit composite layer by using a resin film, and the sixth insulating layer is formed. A step of forming the sixth layer of the wiring circuit layer and forming the sixth layer of the insulation-wiring circuit composite layer is provided.

In the present invention, the number of layers of the insulation-wiring circuit composite layer of the multilayer printed wiring board is not limited to six. The number of layers of the insulation-wiring circuit composite layer may be 6 layers, 6 layers or more, or 7 layers or more.

When the number of layers of the insulation-wiring circuit composite layer in the multilayer printed wiring board is 7 or more, the nth layer (n is an integer of 7 or more) is the (n-1) layer. Formed by forming the nth insulating layer on the insulation-wiring circuit composite layer of the eyes using a resin film and forming the nth wiring circuit layer on the nth insulating layer. can do.

The number of layers (that is, n) of the insulation-wiring circuit composite layer 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 on an insulating-wiring circuit composite layer using a resin film and forming a wiring circuit layer on the insulating layer are repeated. Therefore, it is preferable to form an insulation-wiring circuit composite layer of 7 or more layers.

The number of layers (that is, n) of the insulation-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 layers (that is, n) of the insulation-wiring circuit composite layer is not less than the lower limit and not more 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 the m-th layer (m is an integer of 1 or more) insulating layer is formed (insulation layer forming step), and on the m-th layer insulating layer. Before forming the wiring circuit layer of the mth layer (wiring circuit layer forming step), it is preferable to provide a via hole forming step and a desmear processing step in this order. The swelling treatment step may be performed or the roughening treatment step may be performed before or after the desmear treatment step. The desmear treatment step may also serve as a roughening treatment step. The swelling treatment step and the roughening treatment 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 treatment step, the roughening treatment step, the via hole forming step, the desmear treatment step, the wiring circuit layer forming step, and the main curing step will be specifically described.

<Insulation layer forming process>
The insulating layer is formed by curing a resin film. The insulating layer when the wiring circuit layer is formed is obtained by advancing the curing of the resin film. The above-mentioned curing may be pre-curing or main curing. The above-mentioned curing includes pre-curing that can be further cured. From the viewpoint of suppressing deterioration of the insulating layer, the above-mentioned curing is preferably pre-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 material layer of a resin film. When the curing is pre-curing in the insulating layer forming step, it is preferable that the main curing step described later is performed.

The curing of the resin film is performed by heating.

When the resin film is pre-cured in the insulating layer forming step, the heating temperature of the resin film is preferably 90 ° C. or higher, more preferably 100 ° C. or higher, preferably 190 ° C. or lower, and more preferably 180 ° C. or lower. Is. When the heating temperature is equal to or higher than the lower limit and lower than the upper limit, rapid volatilization of the solvent or 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, and more preferably 1. .75 hours or less. When the heating time is equal to or more than the above lower limit and not more than the above upper limit, the amount of resin etched in the roughening treatment step can be controlled and the surface roughness can be reduced, so that the obtained multilayer printed wiring board can be obtained. It is possible to suppress the occurrence of cracks or cracks in the insulating layer and the wiring circuit layer.

When the resin film is finally cured in the insulating layer forming step, the heating temperature of the resin film is (T + 30) ° C. or higher and (T + 80) ° C. or lower. By setting the heating temperature of the resin film in the case of main curing of the resin film within the above range, it is possible to suppress the occurrence of cracks or cracks in the insulating layer and the wiring circuit layer.

When the resin film is finally 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, still more preferably 190 ° C. or higher, preferably 210 ° C. or lower. , More preferably 205 ° C or lower, still more preferably 200 ° C or lower. Further, in the case of main curing of the resin film, the heating temperature of the resin film is preferably (T + 40) ° C. or higher, preferably (T + 60) ° C. or lower. When the heating temperature is equal to or higher than the lower limit and lower than the upper limit, it is possible to suppress the occurrence of cracks or cracks in the insulating layer and the wiring circuit layer. In particular, the resin film according to the present invention is suitably used for forming an insulating layer by main curing the resin film by heating at 190 ° C. or higher and 200 ° C. or lower.

When the resin film is finally 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, and more preferably 1. .75 hours or less. When the heating time is not less than the above lower limit and not more than the above upper limit, it is possible to suppress the occurrence of cracks or cracks in the insulating layer and the wiring circuit layer.

The curing of the resin film may be carried out in a nitrogen environment or in an atmospheric environment.

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

<Swelling treatment 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 treatment step). By performing the above 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. Even when the roughening treatment step is performed, the swelling treatment step does not necessarily have to be performed. In the swelling treatment step, a conventionally known swelling treatment method can be adopted.

Examples of the swelling treatment include a method of treating an insulating layer (cured product (pre-cured 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 solution. ..

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 carried out by treating the insulating layer at a temperature of 30 ° C. to 85 ° C. for 1 minute to 30 minutes using, for example, a swelling liquid containing a 40 wt% ethylene glycol aqueous solution or the like. The temperature of the swelling treatment is preferably 50 ° C. or higher and 85 ° C. or lower. If the temperature of the swelling treatment is too low, the swelling treatment takes a long time, and the adhesive strength between the insulating layer and the wiring circuit layer tends to be low.

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

The roughening treatment involves 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, and an insulating layer (a cured product of a resin film (pre-cured product)). A method of processing the above can be mentioned.

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

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

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

<Beer hall 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 via hole forming step). When the method for manufacturing a multilayer printed wiring board according to the present invention includes the swelling treatment step and the roughening treatment step, it is preferable that the method is performed after the roughening treatment step. By performing the via hole forming step, the wiring circuit layer forming step, and the like, an insulating layer in which the 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 adopted.

The via hole is preferably formed by irradiating the 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 to be formed is not particularly limited, but is preferably 60 μm or more, preferably 80 μm or less.

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

In the desmear treatment, an insulating layer (cured product (pre-cured product) of a resin film) is formed by a desmear treatment liquid 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. A method of processing and the like can be mentioned.

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

The desmear treatment step may also serve as the roughening treatment step.

The temperature of the desmear treatment is preferably 60 ° C. or higher and 100 ° C. or lower. The time for the desmear treatment is preferably 5 minutes or more and 45 minutes or less.

<Wiring circuit layer forming process>
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. The wiring circuit (wiring circuit layer) can be satisfactorily 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 adopted.

Examples of the chemical copper liquid used in the electrolytic copper plating process include "Basic Print Gantt MSK-DK" manufactured by Atotech Japan, "Copper Print Gantt MSK" manufactured by Atotech Japan, and "Stabilizer Print Gantt MSK" manufactured by Atotech Japan. And a mixed solution of "Reducer Cu" manufactured by Atotech Japan.

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

In 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.

The copper sulfate aqueous solution used in the electrolytic copper plating process includes "copper sulfate pentahydrate" manufactured by Wako Pure Chemical Industries, Ltd., "sulfuric acid" manufactured by Wako Pure Chemical Industries, Ltd., and "basic leveler capallaside HL" manufactured by Atotech Japan. , And a mixed solution of "corrector Kapalaside GS" manufactured by Atotech Japan.

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

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

<Main curing process>
In the method for manufacturing a multilayer printed wiring board according to the present invention, when the resin film is pre-cured in the insulating layer forming step, after the wiring circuit layer is formed on the insulating layer, the following main curing is performed. Equipped with a process. If the resin film is mainly cured in the insulating layer forming step, the following main curing step may not be provided.

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 higher and (T + 80) ° C. or lower. By setting the heating temperature of the resin film in the case of main curing of the resin film within the above range, the difference in CTE of the insulating layer can be suppressed to a small size, and cracks or cracks in the insulating layer of the obtained multilayer printed wiring board can be suppressed. The occurrence can be suppressed.

The heating temperature in the main curing step is preferably a temperature 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 for the purpose.

The heating temperature in the main curing step is preferably 180 ° C. or higher, more preferably 185 ° C. or higher, further preferably 190 ° C. or higher, preferably 210 ° C. or lower, more preferably 205 ° C. or lower, still more preferably 200 ° C. or lower. .. The heating temperature in the main curing step is preferably (T + 40) ° C. or higher, preferably (T + 60) ° C. or lower. When the heating temperature is equal to or higher than the lower limit and lower than the upper limit, the difference in CTE of the insulating layer can be suppressed to a small size, and cracks or cracks in the insulating layer and the wiring circuit layer of the obtained multilayer printed wiring board can be further suppressed. It can be effectively suppressed. In particular, the resin film according to the present invention is suitably used for forming an insulating layer by main curing the resin film by heating at 190 ° C. or higher and 200 ° C. or lower.

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, and more preferably 1.75 hours or less. When the heating time is not less than the above lower limit and not more than the above upper limit, the difference in CTE of the insulating layer can be suppressed to a small size, and the occurrence of cracks or cracks in the insulating layer and the wiring circuit layer of the obtained multilayer printed wiring board is further increased. It can be effectively suppressed.

In the method for manufacturing a multilayer printed wiring board according to the present invention, for example, the insulating layer forming step, the swelling treatment step, the roughening treatment step, the via hole forming step, the desmear treatment step, the wiring circuit layer forming step, and the wiring circuit layer forming step. By repeating this 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 the final step of forming the insulation-wiring circuit composite layer is performed, the insulation-wiring circuit composite layer is further subjected to the same conditions as the main curing step. May be heated.

Hereinafter, the method for manufacturing the multilayer printed wiring board according to the present invention, the details of the resin film used for the multilayer printed wiring board, the details of each component of the resin film according to the present invention, the use of the resin film according to the present invention, and the like 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, and the like. Examples thereof include divinylbenzyl ether compounds, polyarylate compounds, diallylphthalate compounds, benzoxazole compounds, acrylate compounds and silicone compounds. Only one kind of the thermosetting compound may be used, or two or more kinds may be used in combination.

From the viewpoint of improving the coefficient of thermal expansion, the thermosetting compound preferably contains the epoxy compound or the maleimide compound, and more preferably contains the epoxy compound.

From the viewpoint of more effectively suppressing the occurrence of cracks or cracks in the insulating layer around the via hole, the maleimide compound is preferably an alkylmaleimide compound.

Examples of the epoxy compound include bisphenol A type epoxy compound, bisphenol F type epoxy compound, bisphenol S type epoxy compound, phenol novolac type epoxy compound, biphenyl type epoxy compound, biphenyl novolac type epoxy compound, biphenol type epoxy compound, and naphthalene type epoxy compound. , Fluolene type epoxy compound, phenol aralkyl type epoxy compound, naphthol aralkyl type epoxy compound, dicyclopentadiene type epoxy compound, anthracene type epoxy compound, adamantan skeleton epoxy compound, tricyclodecane skeleton epoxy compound, naphthylene ether type Examples thereof include epoxy compounds and epoxy compounds having a triazine nucleus as a skeleton.

From the viewpoint of further lowering the dielectric loss tangent, the epoxy compound preferably contains an epoxy compound having an aromatic skeleton, preferably contains an epoxy compound having a naphthalene skeleton or a phenyl skeleton, and an epoxy having an aromatic skeleton. More preferably, it is a compound.

From the viewpoint of further lowering the dielectric loss tangent and increasing the flexibility of the resin film and the insulating layer, the epoxy compound preferably contains a liquid epoxy compound at 25 ° C. and a solid epoxy compound at 25 ° C. ..

The viscosity of the epoxy compound liquid at 25 ° C. at 25 ° C. is preferably 1000 mPa · s or less, and 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 Leologica Instruments) or the like is used.

The molecular weight of the epoxy compound is more preferably 1000 or less. In this case, even if the component excluding the solvent in the resin film is 100% by weight and the content of the inorganic filler is 50% by weight or more, a resin material having high fluidity at the time of forming the insulating layer can be obtained. Therefore, when the uncured resin film or the B-staged product 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 and 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% in 100% by weight of the components excluding the solvent in the resin film. By weight or more, 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 lowered, and the electrical characteristics can be improved. Further, by using the inorganic filler, the dimensional change due to the heat of the cured product is further reduced. 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, talcite, clay, mica, hydrotalcite, alumina, magnesium oxide, aluminum hydroxide, aluminum nitride, and boron nitride.

The surface roughness of the surface of the cured product is reduced, the adhesive strength between the cured product and the wiring circuit layer is further increased, finer wiring is formed on the surface of the cured product, and better insulation reliability is achieved by 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. Further, 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 silica is preferably spherical.

The inorganic filler is spherical silica from the viewpoint of advancing the curing of the resin regardless of the curing environment, effectively increasing the glass transition temperature of the cured product, and effectively reducing the coefficient of thermal expansion of the cured product. Is preferable.

The average particle size of the inorganic filler is preferably 50 nm or more, more preferably 100 nm or more, still more preferably 500 nm or more, preferably 5 μm or less, more preferably 2 μm or less, still more preferably 1 μm or less. When the average particle size of the inorganic filler is not less than the above lower limit and not more than the above 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 further improved. It can be further enhanced.

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

The inorganic filler is preferably spherical, 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 surface-treating the inorganic filler, the surface roughness of the surface of the roughened 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 surface-treated, finer wiring can be formed on the surface of the cured product, and even better 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, an aluminum coupling agent, and the like. Examples of the silane coupling agent include methacrylsilane, acrylicsilane, aminosilane, imidazolesilane, vinylsilane, and epoxysilane.

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, and particularly preferably 68% by weight in 100% by weight of the component excluding the solvent in the resin film. % Or more, preferably 90% by weight or less, more preferably 80% by weight or less, still more preferably 75% by weight or less, and particularly preferably 73% by weight or less. When the content of the inorganic filler is at least the above lower limit, the dielectric loss tangent is effectively lowered. When the content of the inorganic filler is not less than the above lower limit and not more than the above 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 done. Further, with this amount of the inorganic filler, it is possible to reduce 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 above-mentioned curing agent is not particularly limited. Conventionally known curing agents can be used as the curing agent. Only one kind of the above-mentioned curing agent may be used, or two or more kinds may be used in combination.

Examples of the curing agent include an amine compound (amine curing agent), a thiol compound (thiol curing agent), an imidazole compound, a phosphine compound, a dicyandiamide, a phenol compound (phenol curing agent), a cyanate compound (cyanate curing agent), and an acid anhydride. Examples thereof include an active ester compound, a carbodiimide compound (carbodiimide curing agent), and a benzoxazine compound (benzoxazine curing agent). The curing agent preferably has a functional group capable of reacting with the epoxy group of the epoxy compound.

From the viewpoint of further enhancing the thermal dimensional stability and lowering the dielectric adjacency, 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 contain the component of. That is, the resin film preferably contains a curing agent containing at least one component of a phenol compound, a cyanate compound, an acid anhydride, an active ester compound, a carbodiimide compound, and a benzoxazine compound.

In the present specification, "at least one component of a phenol compound, a cyanate compound, an acid anhydride, an active ester compound, a carbodiimide compound, and a benzoxazine compound" may be referred to as "component X".

Therefore, it is preferable that the resin film contains a curing agent containing the component X. As the component X, only one kind may be used, or two or more kinds 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 products of the above phenol compounds include novolak-type phenol (“TD-2091” manufactured by DIC), biphenyl novolac-type phenol (“MEH-7851” manufactured by Meiwa Kasei Co., Ltd.), and aralkyl-type phenol compound (“MEH” manufactured by Meiwa Kasei Co., Ltd.). -7800 "), and phenols having an aminotriazine skeleton ("LA1356 "and" LA3018-50P "manufactured by DIC) and the like can be mentioned.

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 triquantized. Examples of the novolak type cyanate ester resin include phenol novolac type cyanate ester resin and alkylphenol type cyanate ester resin. Examples of the bisphenol type cyanate ester resin include bisphenol A type cyanate ester resin, bisphenol E type cyanate ester resin, and tetramethyl bisphenol F type cyanate ester resin.

Commercially available products of the above cyanate ester compounds include a phenol novolac type cyanate ester resin (“PT-30” and “PT-60” manufactured by Lonza Japan Co., Ltd.) and a prepolymer in which a bisphenol type cyanate ester resin is triquantized (Lonza Japan). Examples thereof include "BA-230S", "BA-3000S", "BTP-1000S" and "BTP-6020S") manufactured by the same company.

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

Examples of the commercially available product of the acid anhydride include "Ricacid TDA-100" manufactured by Shin Nihon Rika Co., Ltd.

The active ester compound means a compound containing 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 between a carboxylic acid compound or a thiocarboxylic acid compound and 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, a naphthalene ring which may have a substituent, and the like. Examples of the substituent include a hydrocarbon group. The hydrocarbon group has preferably 12 or less carbon atoms, more preferably 6 or less carbon atoms, and even more preferably 4 or less carbon atoms.

The combination of X1 and X2 includes a combination of a benzene ring which may have a substituent and a benzene ring which may have a substituent, and a benzene ring which may have a substituent. Examples thereof include 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 above active ester compound is not particularly limited. From the viewpoint of further enhancing 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 lowering the dielectric loss tangent of the cured product and increasing the thermal dimensional stability of the cured product, it is more preferable to have a naphthalene ring in the main chain skeleton of the active ester.

Examples of commercially available products of the active ester compound include "HPC-8000-65T", "EXB9416-70BK" and "EXB8100-65T" manufactured by DIC Corporation.

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 for other groups. Only one kind of the carbodiimide compound may be used, or two or more kinds thereof may be used in combination.

In the above formula (2), X is an alkylene group, a group in which a substituent is bonded to an alkylene group, a cycloalkylene group, a group in which a substituent is bonded to a cycloalkylene group, an arylene group, or a substituent bonded to an arylene group. It represents a group and p represents an integer of 1-5. When there are a plurality of X's, the plurality of X's may be the same or different.

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

Commercially available products of the above carbodiimide compounds include "carbodilite V-02B", "carbodilite V-03", "carbodilite V-04K", "carbodilite V-07", "carbodilite V-09", and "carbodilite" manufactured by Nisshinbo Chemical Co., Ltd. Examples thereof include "10M-SP" and "Carbodilite 10M-SP (revised)", and "Stavaxol P", "Stavaxol P400" and "Hikazil 510" manufactured by Rheinchemy.

Examples of the benzoxazine compound include P-d type benzoxazine and Fa type benzoxazine.

Examples of commercially available products of the benzoxazine compound include "P-d type" manufactured by Shikoku Chemicals Corporation.

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, and more preferably 120 parts by weight or less with respect to 100 parts by weight of the thermosetting compound. be. When the content of the component X is not less than the above lower limit and not more than the above upper limit, the curability is further improved, the thermal dimensional stability is further enhanced, and the volatilization of the residual unreacted component can be further suppressed.

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

[Hardening accelerator]
The resin film preferably contains a curing accelerator. By using the above-mentioned curing accelerator, the curing rate becomes even faster. By rapidly curing the resin film, the crosslinked structure in the cured product becomes uniform, the number of unreacted functional groups decreases, and as a result, the crosslinked density increases. The curing accelerator is not particularly limited, and conventionally known curing accelerators can be used. As the curing accelerator, only one kind may be used, or two or more kinds 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 organic metal compounds. Agents and the like can be mentioned.

Examples of the imidazole compound include 2-undecylimidazole, 2-heptadecylimidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, and 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 Decylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6- [2' -Methylimidazolyl- (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 And so on.

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

Examples of the phosphorus compound include triphenylphosphine and the like.

Examples of the organic metal compound include zinc naphthenate, cobalt naphthenate, tin octylate, cobalt octylate, bisacetylacetonate cobalt (II) and trisacetylacetonate cobalt (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 lowering the curing temperature, the content of the anionic curing accelerator is preferably 20% by weight or more, more preferably 50% by weight or more, still more preferably 80% by weight in 100% by weight of the curing accelerator. It is 100% by weight or more, most preferably 100% by weight (total amount).

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 above lower limit and not more than the above upper limit, the resin film is efficiently cured. When the content of the curing accelerator is in a more preferable range, the storage stability of the resin film is further improved, and a better cured product can be obtained.

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

The thermoplastic resin is preferably a phenoxy resin or polyimide from the viewpoint of effectively lowering the dielectric loss tangent and effectively enhancing the adhesion of the metal wiring regardless of the curing environment. By using the phenoxy resin or polyimide, deterioration of embedding property in holes or irregularities of the circuit board of the resin film and non-uniformity of the inorganic filler can be suppressed. Further, by using the phenoxy resin or polyimide, the melt viscosity can be adjusted, so that the dispersibility of the inorganic filler is improved, and the resin composition or the B-staged product is less likely to wet and spread in an unintended region during the curing process. Become.

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

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

Examples of commercially available phenoxy resins include "YP50", "YP55" and "YP70" manufactured by Nippon Steel & Sumitomo Metal Corporation, and "1256B40", "4250", "4256H40" and "4256H40" manufactured by Mitsubishi Chemical Corporation. 4275 ”,“ YX6954BH30 ”,“ YX8100BH30 ”and the like.

From the viewpoint of obtaining a resin film having better storage stability, the weight average molecular weights of the thermoplastic resin and the phenoxy resin are preferably 5000 or more, more preferably 10,000 or more, preferably 100,000 or less, and more preferably 50,000 or less. Is.

The weight average molecular weight of the thermoplastic resin and the phenoxy resin indicates the polystyrene-equivalent weight average molecular weight 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 (the content of the phenoxy resin when the thermoplastic resin is a phenoxy resin) is preferably 1 weight in 100% by weight of the components excluding the inorganic filler and the solvent in the resin film. % Or more, more preferably 2% by weight or more, preferably 30% by weight or less, and more preferably 20% by weight or less. When the content of the thermoplastic resin is not less than the above lower limit and not more than the above upper limit, the embedding property of the resin film in the holes or irregularities of the circuit board is improved. When the content of the thermoplastic resin is at least the above lower limit, the formation of the resin film becomes easier and a better insulating layer can be obtained. When the content of the thermoplastic resin is not more than the upper limit, the coefficient of thermal expansion of the cured product is further lowered. When the content of the thermoplastic resin is not more than the above 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 above solvent, the viscosity of the resin film can be controlled in a suitable range, and the coatability of the resin film can be improved. Further, the solvent may be used to obtain a slurry containing the inorganic filler. Only one kind of the solvent may be used, or two or more kinds may be used in combination.

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, and methyl ethyl ketone. Examples thereof include N, N-dimethylformamide, methyl isobutyl ketone, N-methyl-pyrrolidone, n-hexane, cyclohexane, cyclohexanone and naphtha as 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 ingredients]
For the purpose of improving impact resistance, heat resistance, resin compatibility, workability, etc., the above resin film includes a leveling agent, a flame retardant, a coupling agent, a coloring agent, an antioxidant, an ultraviolet deterioration inhibitor, and an extinguishing agent. Foaming agents, thickening agents, rocking denaturing agents and the like may be added.

Examples of the coupling agent include a silane coupling agent, a titanium coupling agent, an aluminum coupling agent, and the like. Examples of the silane coupling agent include vinylsilane, aminosilane, imidazolesilane, and epoxysilane.

(Resin film)
A resin film (B-staged product / B-stage film) can be obtained by molding the resin composition into a film. The resin film is preferably a B stage film. The resin film is preferably a thermosetting resin film.

Examples of a method for obtaining a resin film by molding the resin composition into a film form include the following methods. An extrusion molding method in which a resin composition is melt-kneaded using an extruder, extruded, and then molded into a film by a T-die, a circular die, or the like. A casting molding method in which a resin composition containing a solvent is cast and molded into a film. Other conventionally known film forming methods. The extrusion molding method or the casting molding method is preferable because it can be made thinner. The film includes a sheet.

A resin film as a B stage film can be obtained by molding the resin composition into a film and heating and drying it at 50 ° C. to 150 ° C. for 1 to 10 minutes to the extent that curing by heat does not proceed too much. can.

The film-like resin composition obtained by the drying step as described above 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 can be further cured.

The resin film does not have to be a prepreg. When the resin film is not a prepreg, migration does not occur along the glass cloth or the like. Further, when the resin film is laminated or pre-cured, unevenness due to the glass cloth does not occur on the surface. 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 mold-released, if necessary.

From the viewpoint of controlling the degree of curing of the resin film more uniformly, the thickness of the resin film is preferably 5 μm or more, preferably 200 μm or less. When the resin film is used as the insulating layer of the circuit, the thickness of the insulating layer formed by the resin film is preferably equal to or larger than the thickness of the conductor layer (wiring circuit layer) forming the circuit. The thickness of the insulating layer is preferably 5 μm or more, and 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 further preferably less than 150 nm. In this case, the adhesive strength between the cured product and the wiring circuit layer is increased, and the surface of the insulating layer forms finer wiring. Further, the conductor loss can be suppressed and the signal loss can be suppressed low. The arithmetic mean 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 Co., Ltd.)
Naphthalene type epoxy compound ("HP-4032D" manufactured by DIC Corporation)
Naphthol aralkyl type epoxy compound (“ESN-475V” manufactured by Nippon Steel & Sumitomo Metal Corporation) Maleimide compound:
N-Phenylmaleimide compound ("BMI-4000" manufactured by Daiwa Kasei Kogyo Co., Ltd.)
N-alkylbismaleimide compound (“BMI-1500” manufactured by Designer Molecules Inc.)

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

(Hardener)
Ingredient X:
Phenol novolac compound ("LA-1356" manufactured by DIC Corporation)
Active ester compound-containing liquid ("EXB-9416-70BK" manufactured by DIC Corporation, solid content 70% by weight)
Carbodiimide compound-containing liquid ("V-03" manufactured by Nisshinbo Chemical Co., Ltd., solid content 50% by weight)
Benzoxazine compound ("P-d type" manufactured by Shikoku Chemicals Corporation)

(Hardening accelerator)
Diazabicyclononen (DBN)
Dimethylaminopyridine ("DMAP" manufactured by Wako Pure Chemical Industries, Ltd.)
2-Phenyl-4-methylimidazole ("2P4MZ" manufactured by Shikoku Chemicals Corporation, anionic curing accelerator)

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

(Synthesis Example 1)
300.0 g of tetracarboxylic dianhydride (“BisDA-1000” manufactured by SABIC Japan GK) and 665.5 g of cyclohexanone were placed in a reaction vessel equipped with a stirrer, water divider, thermometer and nitrogen gas introduction tube. 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 Co., Ltd.) and 54.7 g of 1,3-bisaminomethylcyclohexane (manufactured by Mitsubishi Gas Chemical Company, Inc.) were added dropwise to 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 carried out at 140 ° C. for 10 hours. In this way, a polyimide compound-containing solution (nonvolatile content 26.8% by weight) was obtained. The molecular weight of the obtained polyimide compound (weight average molecular weight obtained by the following GPC measurement) was 20000. The molar ratio of the acid component / amine component was 1.04.

GPC (Gel Permeation Chromatography) Measurement:
A high performance liquid chromatograph system manufactured by Shimadzu Corporation was used, and measurement was carried out using tetrahydrofuran (THF) as a developing medium at a column temperature of 40 ° C. and a flow velocity of 1.0 ml / min. "SPD-10A" was used as a detector, and two columns of "KF-804L" (exclusion limit molecular weight 400,000) manufactured by Shodex Co., Ltd. were connected in series. Tosoh's "TSK standard polystyrene" is used as the standard polystyrene, and the weight average molecular weight Mw = 354,000, 189,000, 98,900, 37,200, 17,100, 9,830, 5,870, 2, Calibration curves were made using 500, 1,050, and 500 materials and the molecular weight was calculated.

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

Preparation of resin film:
After applying the obtained resin material on the release-treated surface of the release-treated PET film (Toray Industries, Inc. "XG284", thickness 25 μm) using an applicator, it is placed in a gear oven at 100 ° C. for 3 minutes. It was dried and the solvent was volatilized. In this way, a laminated film (laminated film of PET film and resin film) in which a resin film (B stage film) having a thickness of 40 μm is laminated on the PET film was obtained.

(evaluation)
(1) Peak temperature T
The exothermic peak associated with the curing of the obtained resin film (B stage film) was evaluated using a differential scanning calorimetry device (“Q2000” manufactured by TA Instrument Co., Ltd.). 8 mg of the resin film was taken on a special aluminum pan and covered with a special jig. This dedicated aluminum pan and an empty aluminum pan (reference) are installed in the heating unit and heated from -30 ° C to 250 ° C at a heating rate of 3 ° C / min under a nitrogen atmosphere, and reverse heat flow and non-reverse. The heat flow was observed. The heat generation peak observed in the non-reverse heat flow was defined as the heat generation peak of the resin film. In the obtained exothermic peak, the peak temperature T of the exothermic peak having the maximum peak height was obtained among the exothermic peaks having the exothermic peak top temperature of 130 ° C. or higher and 200 ° C. or lower.

(2) Average coefficient of thermal expansion (CTE)
The resin film was peeled off from the obtained laminated film.

This resin film 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 product (1) of the resin film.

This resin film 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 (heating time 5 times longer than the heating time obtained from the cured product (1) of the resin film). ).

This resin film 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 15 hours to obtain a cured product (3) of the resin film (heating time 10 times longer than the heating time obtained from the cured product (1) of the resin film).

The T at the curing temperature means the peak temperature T. Further, as shown in Table 1, the resin film was cured in an atmospheric environment or a nitrogen environment.

The cured products (1) to (3) of the obtained resin film were cut into a size of 3 mm × 25 mm × thickness 40 μm. Using a thermomechanical analyzer (“EXSTAR TMA / SS6100” manufactured by SII Nanotechnology Co., Ltd.), the cured product cut at 25 ° C or higher and 150 ° C under the conditions of a tensile load of 33 mN and a heating rate of 5 ° C / min. The following average coefficient of thermal expansion (ppm / ° C) was calculated.

_{The measured average thermal expansion coefficient CTE 1.5h} of the cured product (1) of the resin film, the average thermal expansion coefficient CTE _7.5h of the cured product (2) of the resin film, and the cured product (3) of the resin film. The following was calculated from the average thermal expansion coefficient CTE _15h.

_Ratio of CTE 7.5h to CTE _1.5h (CTE _7.5h / CTE _1.5h )
Ratio of CTE _15h to CTE _{1.5h (CTE 15h} / CTE _1.5h )
Absolute value of the difference between CTE _1.5h and CTE _7.5h Absolute value of the difference between CTE _1.5h and CTE _15h

[Criteria for determining the average coefficient of thermal expansion]
A: Ratio (CTE _7.5h / CTE _1.5h ) is 0.75 or more and 1.4 or less B: Ratio (CTE _7.5h / CTE _1.5h ) is less than 0.75 or 1.4 A: Ratio (CTE _15h / CTE _1.5h ) is 0.75 or more and 1.2 or less B: Ratio (CTE _15h / CTE _1.5h ) is less than 0.75 or more than 1.2

(3) Cold Impact Test An evaluation board for a cold shock test (an evaluation board including a copper-clad laminate and a 6-layer insulation-wiring circuit composite layer) was produced according to the following. In the evaluation substrate, via holes formed in each layer are connected. That is, the following evaluation was performed on an evaluation board having a multi-stage stack via.

Formation of first layer of insulation-wiring circuit composite layer:
(A1) Laminating process:
A double-sided copper-clad laminate (copper foil thickness of 18 μm on each side, substrate thickness of 0.7 mm, substrate size of 100 mm × 100 mm, “MCL-E679FG” manufactured by Hitachi Kasei Co., Ltd.) was prepared. Both sides 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 was copper-clad laminated on both sides of the roughened copper-clad laminate using "Batch type vacuum laminator MVLP-500 / 600-IIA" manufactured by Meiki Co., Ltd. It was laminated on a board. The laminating conditions were such that the pressure was reduced for 30 seconds to reduce the atmospheric pressure to 13 hPa or less, 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, the resin film was semi-cured (pre-cured) by heating at 130 ° C. for 60 minutes. In this way, a laminated body (1) in which a semi-cured product of a resin film was laminated on a CCL substrate was obtained.

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

(C1) Desmear treatment and roughening treatment:
(C1-1) Swelling treatment:
The obtained laminate (1) was placed in a swelling solution at 60 ° C. (“Swelling Dip Securigant P” manufactured by Atotech Japan) and shaken for 10 minutes. Then, it was washed with pure water.

(C1-2) Permanganate treatment (roughening treatment and desmear treatment):
The swelling-treated laminate (1) was placed in a crude aqueous solution of potassium permanganate (“Concentrate Compact CP” manufactured by Atotech Japan) at 80 ° C. and shaken for 30 minutes. Next, after treating for 2 minutes with a cleaning liquid at 25 ° C. (“Reduction Securigant P” manufactured by Atotech Japan), cleaning was performed with pure water to obtain a laminated body (1) after roughening treatment.

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

(D1) Electroless plating treatment:
The surface of the cured product of the laminated body (1) after the roughening treatment was treated with an alkaline cleaner at 60 ° C. (“Cleaner Securigant 902” manufactured by Atotech Japan Co., Ltd.) for 5 minutes, and degreased and washed. After washing, the cured product was treated with a predip solution (“Predip Neogant B” manufactured by Atotech Japan) at 25 ° C. for 2 minutes. Then, the cured product was treated with an activator solution at 40 ° C. (“Activator Neogant 834” manufactured by Atotech Japan Co., Ltd.) for 5 minutes, and a palladium catalyst was attached. 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 was placed in a chemical copper solution (Atotech Japan's "Basic Print Gantt MSK-DK", "Copper Print Gantt MSK", "Stabilizer Print Gantt MSK", and "Reducer Cu") for electroless plating. Was carried out until the plating thickness became about 0.5 μm. After electroless plating, annealing treatment was performed at a temperature of 120 ° C. for 30 minutes in order to remove residual hydrogen gas. All the steps up to the electroless plating step were carried out using a beaker scale with 2 L of the treatment liquid and shaking the cured product.

(E1) Resist formation:
A dry film resist (“RY5125” manufactured by Hitachi Kasei Co., Ltd.) was attached using a hot roll laminator. The laminating conditions were a temperature of 100 ° C., a pressure of 0.4 MPa, and a laminating speed of 1.5 m / min, and then held for 15 minutes. Then, after exposure at 85 mJ / cm ² , a 1 wt% sodium carbonate aqueous solution was spray-treated at 27 ° C. at a spray pressure of 1.2 MPa for 30 seconds for development.

(F1) Electroplating treatment:
Next, electrolytic plating was performed on the cured product subjected to electroless plating until the plating thickness became 25 μm. Copper sulfate solution for electrolytic copper plating ("Copper sulfate pentahydrate" manufactured by Wako Pure Chemical Industries, Ltd., "Sulfate" manufactured by Wako Pure Chemical Industries, Ltd., "Basic Leveler Capallaside HL" manufactured by Atotech Japan, "Basic Leveler Capallaside HL" manufactured by Atotech Japan. Using the corrective agent Kapalacid GS ”), ^{electrolytic plating was carried out by passing a current of 0.6 A / cm 2} until the plating thickness became about 25 μm.

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

(H1) Main curing step:
It was heated at (T + 50) ° C. for 1.5 hours with respect to the peak temperature T.

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

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

(B2) Via hole forming step:
(B1) Via holes were formed in the same manner as in the step carried out in the via hole forming step, except that the laminated body (1) was changed to the laminated body (2).

(C2) Desmear treatment and roughening treatment:
(C1) The steps carried out in the desmear treatment and the roughening treatment were carried out in the same manner except that the laminated body (1) was changed to the laminated body (2), and the laminated body (2) after the roughening treatment was obtained.

(D2) Electroless plating treatment:
(D1) The electroless plating treatment was performed in the same manner as in the process carried out in the electroless plating treatment, except that the laminated body (1) after the roughening treatment was changed to the laminated body (2) after the roughening treatment. rice field.

(F2) Electroplating treatment:
After the (d2) electroless plating treatment, the electroless plating treatment was performed in the same manner as in the (f1) electrolytic plating treatment.

(H2) Main curing step:
(H1) In the same manner as in the main curing step, the mixture was heated at (T + 50) ° C. for 1.5 hours.

In this way, the second layer of the insulation-wiring circuit composite layer was formed on the first layer of the insulation-wiring circuit composite layer.

Formation of third insulation-wiring circuit composite layer:
A third layer of insulation-wiring circuit composite layer was formed on the second layer of insulation-wiring circuit composite layer in the same manner as in the process performed in the formation of the second layer of insulation-wiring circuit composite layer.

Formation of 4th insulation-wiring circuit composite layer:
A fourth layer of insulation-wiring circuit composite layer was formed on the third layer of insulation-wiring circuit composite layer in the same manner as in the process performed in the formation of the second layer of insulation-wiring circuit composite layer.

Formation of 5th insulation-wiring circuit composite layer:
(A5) Laminating process:
(A2) In the same manner as in the step carried out in the laminating step, a laminated body (5) in which a semi-cured resin film was laminated on the fourth layer of the insulating-wiring circuit composite layer was obtained.

(B5) Via hole forming step:
(B1) Via holes were formed in the same manner as in the step carried out in the via hole forming step, except that the laminated body (1) was changed to the laminated body (5).

(C5) Desmear treatment and roughening treatment:
(C1) The steps carried out in the desmear treatment and the roughening treatment were carried out in the same manner except that the laminated body (1) was changed to the laminated body (5), and the laminated body (5) after the roughening treatment was obtained.

(D5) Electroless plating treatment:
(D1) The electroless plating treatment was performed in the same manner as in the process carried out in the electroless plating treatment, except that the laminated body (1) after the roughening treatment was changed to the laminated body (5) after the roughening treatment. rice field.

(E5) Resist formation:
(E1) Development was carried out in the same manner as in the process carried out in resist formation.

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

(G5) DFR peeling and etching treatment:
(G1) The DFR peeling and etching treatments were carried out in the same manner as in the steps carried out in the DFR peeling and etching treatments.

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

In this way, the fifth layer of the insulation-wiring circuit composite layer was formed on the fourth layer of the insulation-wiring circuit composite layer.

Formation of 6th insulation-wiring circuit composite layer:
A sixth layer of insulation-wiring circuit composite layer was formed on the fifth layer of insulation-wiring circuit composite layer in the same manner as in the process performed in the formation of the second layer of insulation-wiring circuit composite layer.

In this way, an evaluation substrate in which the first to sixth layers of the insulation-wiring circuit composite layer were formed on the copper-clad laminate was produced. In the obtained evaluation board, of the wiring circuit layers of the first to sixth layers, only the first and fifth wiring circuit layers have a pattern.

Evaluation of thermal shock test (cracking or cracking of insulating layer):
The obtained evaluation substrate was subjected to a liquid tank cold heat impact test under the following two conditions.

Test condition 1: -55 ° C to 125 ° C, 5 minutes each, 1000 cycles Test condition 2: -65 ° C to 150 ° C, 5 minutes each, 1000 cycles

(I) Cracks or cracks in the insulating layer and wiring circuit layer Observe the insulating layer around the via hole and the wiring circuit layer in the via part using a scanning electron microscope (SEM) on the evaluation substrate that has been subjected to the liquid tank thermal shock test. did. In addition, the insulating layer and the wiring circuit layer in the region other than the area around the via hole were also observed.

[Criteria for cracking or cracking (around via holes) in the insulating layer and wiring circuit layer]
◯: No cracks or cracks occur in the insulating layer around the via hole and the wiring circuit layer in the via part ×: There are cracks or cracks in the insulating layer around the via hole or the wiring circuit layer in the via part.

[Criteria for cracking or cracking the insulating layer and wiring circuit layer (other than around the via hole)]
◯: No cracks or cracks occur in the insulating layer or wiring circuit layer in the area other than the area around the via hole ×: Cracks or cracks occur in the insulating layer or wiring circuit layer in the area other than the area around the via hole.

(Ii) Connection reliability Before and after the liquid tank thermal shock test, the resistance of the via connection part was measured using a resistance tester (“RM3545” manufactured by Hioki Electric Co., Ltd.). Before and after the liquid tank cold heat impact test was carried out, the rate of change in the resistance value of the evaluation board (resistance value after the liquid tank cold heat shock test / resistance value after the liquid tank cold heat shock test × 100) was determined.

[Criteria for connection reliability]
◯: Resistance value change rate is less than 10% ×: Resistance value change rate is 10% or more

The composition and results are shown in Table 1 below.

1 ... Multi-layer printed wiring board 11 ... Board 11a ... Hole 12 ... Wiring circuit layer 13, 13A, 13B ... Insulation layer (first insulation layer)
14 ... Wiring circuit layer (first wiring circuit layer)
15, 15A, 15B ... Insulation layer (second insulation layer)
16 ... Wiring circuit layer (second wiring circuit layer)
17 ... Insulation layer (third insulation layer)
18 ... Wiring circuit layer (third wiring circuit layer)
19 ... Insulation layer (fourth insulation layer)
20 ... Wiring circuit layer (fourth wiring circuit layer)
21 ... Insulation layer (fifth insulation layer)
22 ... Wiring circuit layer (fifth wiring circuit layer)
23 ... Insulation layer (sixth insulation layer)
24 ... Wiring circuit layer (6th wiring circuit layer)
51, 52 ... Resist pattern

Claims (12)

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.
It is a method for manufacturing a multilayer printed wiring board that forms a plurality of insulating layers using a resin film.
A resin film is used to form a first insulating layer on a circuit board, and a wiring circuit layer of the first layer is formed on the insulating layer of the first layer to form an insulating-wiring circuit of the first layer. The process of forming the composite layer and
A second insulating layer is formed on the first insulating-wiring circuit composite layer using a resin film, and a second wiring circuit layer is formed on the second insulating layer. The process of forming the second layer of insulation-wiring circuit composite layer,
A resin film is used to form a third insulating layer on the second insulating-wiring circuit composite layer, and a third wiring circuit layer is formed on the third insulating layer. The process of forming the third layer of insulation-wiring circuit composite layer,
A resin film is used to form a fourth insulating layer on the third insulating-wiring circuit composite layer, and a fourth wiring circuit layer is formed on the fourth insulating layer. The process of forming the fourth layer of insulation-wiring circuit composite layer,
A fifth insulating layer is formed on the fourth insulating-wiring circuit composite layer using a resin film, and a fifth wiring circuit layer is formed on the fifth insulating layer. The process of forming the fifth layer of insulation-wiring circuit composite layer,
A sixth insulating layer is formed on the fifth insulating-wiring circuit composite layer using a resin film, and a sixth wiring circuit layer is formed on the sixth insulating layer. The sixth layer is provided with a step of forming an insulation-wiring circuit composite layer.
The resin film contains a thermosetting compound and an inorganic filler.
The resin film has a heat generation peak top temperature of 130 ° C. or higher and 200 ° C. or lower as measured by a differential scanning calorimeter.
Of the heat generation peaks having a heat generation peak top temperature of 130 ° C. or higher and 200 ° C. or lower, when the peak temperature of the heat generation peak having the maximum peak height is T ° C., the insulation-wiring of the first to sixth layers. In each of the steps of forming the circuit composite layer, the heating temperature for main curing the resin film is (T + 30) ° C. or higher and (T + 80) ° C. or lower.
The average coefficient of thermal expansion of the first insulating layer of the obtained multilayer printed wiring board at 25 ° C. or higher and 150 ° C. or lower is set to CTE ₁ .
When the average coefficient of thermal expansion of 25 ° C. or higher and 150 ° C. or lower of the fifth insulating layer in the obtained multilayer printed wiring board is set to CTE ₅ .
A method for manufacturing a multilayer printed wiring board in which the ratio of _{CTE 1} to CTE _{5 is 0.75 or more and 1.4 or less.} The method for manufacturing a multilayer printed wiring board according to claim ₁ , wherein the absolute value of the difference between the CTE 1 and the CTE _{5 is 7 ppm / ° C. or less.} The method for manufacturing a multilayer printed wiring board according to claim 1 or 2, wherein the heating temperature for main curing the resin film is 190 ° C. or higher and 200 ° C. or lower. By repeating the steps of forming an insulating layer on the insulating-wiring circuit composite layer using a resin film and forming the wiring circuit layer on the insulating layer, seven or more insulating-wiring circuit composite layers are formed. The method for manufacturing a multilayer printed wiring board according to any one of claims 1 to 3. The method for producing a multilayer printed wiring board according to any one of claims 1 to 4, wherein the thermosetting compound contains an epoxy compound. Contains thermosetting compounds and inorganic fillers
In the measurement with a differential scanning calorimeter, it has a heat generation peak top temperature of 130 ° C or higher and 200 ° C or lower.
Among the exothermic peaks having the exothermic peak top temperature at 130 ° C. or higher and 200 ° C. or less, the peak temperature of the exothermic peak having the maximum peak height is defined as T ° C.
The average coefficient of thermal expansion of the cured product of the resin film cured at (T + 50) ° C. for 1.5 hours at 25 ° C. or higher and 150 ° C. or lower is set to CTE _1.5h .
When the average coefficient of thermal expansion of the cured product of the resin film cured at (T + 50) ° C. for 7.5 hours is 25 ° C. or higher and 150 ° C. or lower, and the average thermal expansion coefficient is CTE _7.5h .
A _{resin film in which the ratio of CTE 7.5h} to CTE _1.5h is 0.75 or more and 1.4 or less. The resin film according to claim 6, wherein the absolute value of the difference between the CTE _1.5h and the CTE _7.5h is 7 ppm / ° C. or less. The resin film according to claim 6 or 7, wherein the thermosetting compound contains an epoxy compound. The resin film according to any one of claims 6 to 8, which is used for main curing the resin film to form an insulating layer by heating at 190 ° C. or higher and 200 ° C. or lower. One of claims 6 to 9, which is 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. The resin film described in. A circuit board, an insulating layer formed of a resin film, and a wiring circuit layer are provided.
It has a structure in which the insulating layer and the wiring circuit layer are alternately laminated on the circuit board.
On the circuit board, the first layer of the insulation-wiring circuit composite layer composed of the first layer of the insulating layer and the first layer of the wiring circuit layer, the second layer of the insulating layer, and the second layer of the wiring circuit. The second insulation-wiring circuit composite layer composed of layers, the third insulation-wiring circuit composite layer composed of the third insulation layer and the third wiring circuit layer, and the fourth layer. Insulation-wiring circuit composite layer of the 4th layer composed of the insulation layer and the wiring circuit layer of the 4th layer, and the insulation of the 5th layer composed of the insulation layer of the 5th layer and the wiring circuit layer of the 5th layer. -Having at least a wiring circuit composite layer and a sixth insulation-wiring circuit composite layer composed of a sixth insulating layer and a sixth wiring circuit layer.
The resin film contains a thermosetting compound and an inorganic filler.
The resin film has a heat generation peak top temperature of 130 ° C. or higher and 200 ° C. or lower as measured by a differential scanning calorimeter.
The average coefficient of thermal expansion of the first insulating layer at 25 ° C or higher and 150 ° C or lower is defined as CTE ₁ .
When the average coefficient of thermal expansion of the fifth insulating layer between 25 ° C and 150 ° C is set to CTE ₅ .
A multilayer printed wiring board in which the ratio of _{CTE 1} to CTE _{5 is 0.75 or more and 1.4 or less.} The multilayer printed wiring board according to claim 11, wherein the absolute value of the difference between the CTE ₁ and the CTE _{5 is 7 ppm / ° C. or less.}

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