JP2022053025A - Metal-clad laminate and manufacturing method thereof - Google Patents

Abstract

To provide a metal-clad laminate and a manufacturing method thereof capable of suppressing a decrease in the adhesiveness of a metal layer to an insulating layer having a thermosetting polyimide layer in a long-term use accompanied by a temperature change.SOLUTION: A metal-clad laminate 11 includes an insulating layer 12 and a metal layer 13 laminated on one or both sides of the insulating layer 12. The insulating layer 12 includes a thermosetting polyimide layer 21 and a thermosetting resin layer 31 provided between the thermosetting polyimide layer 21 and the metal layer 13. The water absorption rate of the thermosetting resin layer 31 is lower than the water absorption rate of the thermosetting polyimide layer 21.SELECTED DRAWING: Figure 1

Description

The present invention relates to a metal-clad laminate and a method for manufacturing the same.

In recent years, with the utilization of IoT (Internet of Things), electronic devices such as sensors tend to be used in various environments. For example, millimeter waves used in sensors and the like are highly stable to light, weather, and the environment, so they are used in millimeter wave radars of automobiles and are expected to be used in harsher environments. As described above, recent electronic devices may be used in more harsh environments, and along with this, improvement in the environmental resistance performance of the electronic devices is required. Here, for the printed wiring board installed in the electronic device, for example, a metal-clad laminated board as disclosed in Patent Document 1 is used. The metal-clad laminate has, for example, a laminated structure of a polyimide layer as an insulating layer and a copper layer as a metal layer. Even for such metal-clad laminates, there is a tendency that environmental resistance is required for the adhesiveness between the insulating layer and the metal layer from the viewpoint of improving the environmental resistance of electronic devices.

Japanese Unexamined Patent Publication No. 2016-187913

When a thermosetting polyimide layer is used as the insulating layer in the above-mentioned metal-clad laminate, the dimensional stability of the metal-clad laminate can be easily ensured, but the thermosetting is performed in a long-term use accompanied by temperature change. There was a risk that the adhesiveness between the polyimide layer and the metal layer would decrease.

The metal-clad laminate that solves the above problems is a metal-clad laminate comprising an insulating layer and a metal layer laminated on one or both sides of the insulating layer, and the insulating layer is a thermosetting polyimide layer. A thermosetting resin layer provided between the thermosetting polyimide layer and the metal layer is provided, and the water absorption rate of the thermosetting resin layer is lower than that of the thermosetting polyimide layer.

According to this configuration, it is presumed that by suppressing water absorption and dehydration of the heat-sealed resin layer bonded to the metal layer, it is possible to suppress a change in the state of the interface between the metal layer and the heat-sealed resin layer. As a result, it is possible to suppress a decrease in the adhesiveness of the metal layer to the insulating layer having the thermosetting polyimide layer in long-term use accompanied by a temperature change.

In the metal-clad laminate, the heat-sealed resin layer preferably has a water absorption rate of 0.1% or less. According to this configuration, it is possible to further suppress a decrease in the adhesiveness of the metal layer to the insulating layer having the thermosetting polyimide layer in long-term use accompanied by a temperature change.

In the metal-clad laminate, the heat-sealed resin layer preferably has a melting point of 280 ° C. or higher. According to this configuration, the solder heat resistance of the metal-clad laminate can be easily increased.
In the metal-clad laminate, the metal layer is preferably composed of a metal foil having a ten-point average roughness (Rzjis) of 2.0 or less on the main surface to be adhered to the heat-sealed resin layer. According to this configuration, by improving the smoothness of the main surface of the metal foil, it is possible to suppress the skin effect in which the current in the high frequency band concentrates on the surface of the metal layer. It can be fully demonstrated.

In the metal-clad laminate, the coefficient of linear expansion of the thermosetting polyimide layer is preferably in the range of 10 ppm / K or more and 26 ppm / K or less. According to this configuration, for example, the dimensional stability of the metal-clad laminate can be improved.

In the metal-clad laminate, the heat-sealed resin layer is preferably composed of a fluororesin. According to this configuration, the dielectric constant of the insulating layer can be suppressed to a low level, so that, for example, the electrical characteristics in the high frequency band can be sufficiently exhibited.

The above-mentioned metal-clad laminate was measured after performing a heat cycle test under the conditions that the temperature range was -50 ° C to 150 ° C, the holding time was 0 minutes, and the number of repetitions of temperature raising and lowering was 3000 times. The peel strength of the metal layer is preferably 80% or more when the peel strength of the metal layer before the heat cycle test is 100%.

The method for manufacturing a metal-clad laminate includes an insulating layer and a metal layer laminated on one side or both sides of the insulating layer, and the insulating layer includes a thermosetting polyimide layer, the thermosetting polyimide layer, and the above. A metal-clad laminate provided with a heat-sealed resin layer provided between the metal layer and the metal-clad laminate having a water absorption rate lower than that of the thermosetting polyimide layer. The method for producing the above method, wherein the thermoplastic resin film to be the heat-sealed resin layer is arranged between the heat-curable polyimide film to be the heat-curable polyimide layer and the metal foil to be the metal layer. It is preferable to include a step of heat-pressing the body.

According to the present invention, it is possible to suppress a decrease in the adhesiveness of a metal layer to an insulating layer having a thermosetting polyimide layer in a long-term use accompanied by a temperature change.

It is sectional drawing which shows the metal-clad laminated board of this embodiment. It is a schematic diagram explaining the manufacturing method of a metal-clad laminated board.

Hereinafter, an embodiment of a metal-clad laminate and a method for manufacturing the same will be described. In the drawings, the thickness of each layer constituting the metal-clad laminate may be exaggerated.
As shown in FIG. 1, the metal-clad laminate 11 includes an insulating layer 12 and a metal layer 13 laminated on the insulating layer 12. The metal layer 13 of the present embodiment is composed of a first metal layer 13a laminated on one main surface of the insulating layer 12 and a second metal layer 13b laminated on the other main surface of the insulating layer 12. There is.

The insulating layer 12 includes a thermosetting polyimide layer 21 and a thermosetting resin layer 31. The thermosetting resin layer 31 is composed of a first thermosetting resin layer 31a provided between the thermosetting polyimide layer 21 and the first metal layer 13a, and the thermosetting polyimide layer 21 and the second metal layer 13b. It is composed of a second thermosetting resin layer 31b provided between them. As described above, the metal-clad laminate 11 of the present embodiment has the insulating layer 12 having a three-layer structure composed of the thermosetting polyimide layer 21, the first thermosetting resin layer 31a, and the second thermosetting resin layer 31b. It is a double-sided metal-clad laminate having a five-layer structure having metal layers 13 laminated on both sides of the insulating layer 12.

<Thermosetting polyimide layer 21>
The thermosetting polyimide layer 21 can be made of a thermosetting polyimide film. The thermosetting polyimide film is obtained from an acid component and a diamine component. Examples of the acid component include 3,3', 4,4'-biphenyltetracarboxylic dianhydride (s-BPDA), pyromellitic acid and the like. Examples of the diamine component include p-phenylenediamine (PPD), 4,4-diaminodiphenyl ether, m-tridin, 4,4'-diaminobenzanilide and the like. Examples of commercially available thermosetting polyimide films include Upirex-S (trade name) and Upirex-SGA (trade name) manufactured by Ube Kosan Co., Ltd.

The thermosetting polyimide layer 21 contains 3,3', 4,4'-biphenyltetracarboxylic acid dianhydride and p-phenylenediamine from the viewpoint of excellent low dielectric constant, low dielectric loss tangent and other low dielectric properties. It is preferably contained as a copolymerization component. The content of 3,3', 4,4'-biphenyltetracarboxylic acid dianhydride in the thermosetting polyimide layer 21 is preferably 50 mol% or more when the total acid component is 100 mol%. , More preferably 70 mol% or more. The content of p-phenylenediamine in the thermosetting polyimide layer 21 is preferably 50 mol% or more, more preferably 70 mol% or more, when the total diamine component is 100 mol%. As a commercially available thermosetting polyimide film containing 3,3', 4,4'-biphenyltetracarboxylic acid dianhydride and p-phenylenediamine as a copolymerization component, for example, Ube Kosan Co., Ltd. Upirex-SGA (trade name) can be mentioned.

In the thermosetting polyimide film, the main surface to be adhered to the thermosetting resin layer 31 is subjected to a discharge treatment from the viewpoint of enhancing the adhesiveness between the thermosetting polyimide layer 21 and the thermosetting resin layer 31. It is preferable to have. Examples of the discharge treatment include corona discharge treatment, atmospheric pressure plasma discharge treatment, vacuum plasma discharge treatment, and the like. The discharge treatment is preferably performed so that the water contact angle of the main surface to be adhered to the heat-sealed resin layer 31 is 20 ° or less, more preferably 17 ° or less, still more preferably 14 °. It is as follows. The water contact angle of the thermosetting polyimide film is preferably 5 ° or more, more preferably 6 ° or more, for example, from the viewpoint of productivity and the like. The water contact angle can be measured by the sessile drop method using a contact angle meter.

The thickness of the thermosetting polyimide layer 21 is preferably 125 μm or less, for example. The water absorption rate of the thermosetting polyimide layer 21 is preferably in the range of, for example, 1.0% or more and 2.0% or less.

<Heat fusion resin layer 31>
The water absorption rate of the thermosetting resin layer 31 is lower than the water absorption rate of the thermosetting polyimide layer 21. The water absorption rate of the heat-sealed resin layer 31 is preferably 0.1% or less, more preferably 0.07% or less, and further preferably 0.05% or less.

The heat-sealed resin layer 31 preferably has a melting point of 280 ° C. or higher, for example, from the viewpoint of easily increasing the heat resistance of the solder. The melting point of the heat-sealed resin layer 31 is preferably 320 ° C. or lower from the viewpoint of ease of heat-sealing.

The thickness of the first heat-sealed resin layer 31a and the thickness of the second heat-sealed resin layer 31b are preferably 5 μm or more, more preferably 10 μm or more, still more preferably 12.5 μm. That is all. The thickness of the first heat-sealed resin layer 31a and the thickness of the second heat-sealed resin layer 31b are preferably 150 μm or less, more preferably 120 μm or less, still more preferably 100 μm or less. be. The thickness of the first heat-sealed resin layer 31a and the thickness of the second heat-sealed resin layer 31b may be the same or different from each other. From the viewpoint of suppressing twisting and warping of the metal-clad laminate 11, the difference between the thickness of the first heat-sealed resin layer 31a and the thickness of the second heat-sealed resin layer 31b is preferably 3 μm or less. It is preferably 2 μm or less, and more preferably 1 μm or less.

The thickness of the insulating layer 12 of the present embodiment is preferably 10 μm or more, more preferably 20 μm or more, still more preferably 25 μm or more. The thickness of the insulating layer 12 of the present embodiment is preferably 400 μm or less, more preferably 300 μm or less, for example, from the viewpoint of further enhancing flexibility.

The heat-sealed resin layer 31 is preferably made of a fluororesin, for example, from the viewpoint of keeping the dielectric constant low. Among fluororesins, tetrafluoroethylene-hexafluoropropylene copolymer (FEP) or tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA) is used from the viewpoint of having good low dielectric properties and good adhesiveness. ) Is preferable.

<Metal layer 13>
Examples of the metal of the metal layer 13 include gold, silver, copper, copper alloys, aluminum, and aluminum alloys. The first metal layer 13a and the second metal layer 13b may be made of the same metal or may be made of different metals. The metal layer 13 can be formed by using, for example, a copper foil. Examples of the copper foil include electrolytic copper foil and rolled copper foil. The metal foil forming the first metal layer 13a and the metal foil forming the second metal layer 13b may be obtained by the same manufacturing method or may be obtained by different manufacturing methods. ..

The thickness of the first metal layer 13a and the thickness of the second metal layer 13b are preferably in the range of 2 μm or more and 105 μm or less, and more preferably in the range of 2 μm or more and 35 μm or less, respectively. The thickness of the first metal layer 13a and the thickness of the second metal layer 13b may be the same as each other or may be different from each other.

Here, the adhesive strength between the metal layer 13 and the heat-sealed resin layer 31 tends to increase as the surface roughness of the main surface to be adhered to the heat-sealed resin layer 31 becomes coarser in the metal foil. On the other hand, since the main surface of the metal foil is smoother, the skin effect in which the current in the high frequency band is concentrated on the surface of the metal layer 13 is suppressed, so that the electrical characteristics in the high frequency band can be fully exhibited. can. In recent years, as the frequency of electronic devices such as 5G smartphones has increased, the demand for printed wiring boards having a smaller transmission loss has increased. Therefore, when the metal-clad laminate 11 is used as a printed wiring board corresponding to a high frequency band, the metal layer 13 has a ten-point average roughness (Rzjis) of a main surface bonded to the heat-sealed resin layer 31. It is preferably composed of a metal foil of 0 or less. The ten-point average roughness (Rzjis) is defined in JIS B0601 (2001). The ten-point average roughness (Rzjis) on the main surface of the metal foil is more preferably 1.5 or less, still more preferably 1.0 or less.

<Linear expansion coefficient>
By making the coefficient of linear expansion of the insulating layer 12 close to the coefficient of linear expansion of the metal layer 13, the dimensional stability of the metal-clad laminate 11 can be improved. For example, the coefficient of linear expansion of copper is 18 ppm / K. When the metal layer 13 is a copper layer, the coefficient of linear expansion of the insulating layer 12 is preferably in the range of, for example, 10 ppm / K or more and 40 ppm / K or less. The coefficient of linear expansion of the thermosetting polyimide layer 21 constituting the insulating layer 12 is preferably in the range of 10 ppm / K or more and 26 ppm / K or less. For example, even when the coefficient of linear expansion of the thermosetting resin layer 31 is larger than the coefficient of linear expansion of the thermosetting polyimide layer 21, the coefficient of linear expansion of the thermosetting polyimide layer 21 can be set within the above range. The dimensional stability of the metal-clad laminate 11 can be improved.

<Peeling strength of metal layer>
In the metal-clad laminate 11 of the present embodiment, the peel strength of the metal layer 13 measured after performing the heat cycle test under the following conditions is 100% of the peel strength of the metal layer 13 before the heat cycle test. When it is, it is preferably 80% or more.

(Conditions for heat cycle test)
Temperature range: -50 ° C to 150 ° C
Holding time: 0 minutes Raising time: 2 hours Temperature lowering time: 2 hours Number of repetitions of raising and lowering temperature: 3000 times <Manufacturing method of metal-clad laminate 11>
Next, a method for manufacturing the metal-clad laminate 11 will be described.

As shown in FIG. 2, the method for manufacturing the metal-clad laminate 11 includes a step of thermocompression bonding the laminate 111 in which the thermoplastic resin film 131 is arranged between the thermosetting polyimide film 121 and the metal foil 113. There is. The thermosetting polyimide film 121 forms the thermosetting polyimide layer 21 described above. The first thermoplastic resin film 131a and the second thermoplastic resin film 131b form a first heat-sealing resin layer 31a and a second heat-sealing resin layer 31b, respectively. The first metal foil 113a and the second metal foil 113b form the first metal layer 13a and the second metal layer 13b, respectively.

In the step of thermocompression bonding the laminate 111, the laminate 111 is heated so that the temperature of the thermoplastic resin film 131 is equal to or higher than the melting point. The maximum temperature in the step of thermocompression bonding the laminate 111 is preferably Tm + 70 ° C. or lower when the melting point of the thermoplastic resin film 131 is Tm ° C.

The pressure in the step of thermocompression bonding the laminate 111 is preferably in the range of, for example, 0.5 N / mm ² or more and 10 N / mm ² or less, and more preferably 2 N / mm ² or more and 6 N / mm ² or less. Is within the range of.

The heating time in the step of thermocompression bonding the laminate 111 is preferably in the range of, for example, 10 seconds or more and 600 seconds or less, and more preferably 30 seconds or more and 500 seconds or less.
The step of thermocompression bonding the laminated body 111 is preferably performed by using a double belt press device 51. The double belt press device 51 heats and pressurizes while conveying the laminated body 111. The double belt press device 51 has a first transport unit 52 located on the upstream side in the transport direction of the laminated body 111, and a second transport unit 53 located on the downstream side.

The upper first drum 52a and the lower first drum 52b are mounted on the first transport unit 52. The upper second drum 53a and the lower second drum 53b are mounted on the second transport unit 53. An endless upper belt 54 is bridged to the upper first drum 52a and the upper second drum 53a. An endless lower belt 55 is bridged to the lower first drum 52b and the lower second drum 53b. The first drums 52a and 52b are configured to be driven via the belts 54 and 55 by the drive of the second drums 53a and 53b. Each belt 54, 55 is formed of a metal such as stainless steel.

An upper temperature control device 56 and a lower temperature control device 57 are arranged between the first transport unit 52 and the second transport unit 53 so as to face each other with the belts 54 and 55 interposed therebetween. The upper temperature control device 56 and the lower temperature control device 57 heat and pressurize the laminate 111 via the upper belt 54 and the lower belt 55. The upper temperature control device 56 and the lower temperature control device 57 heat and pressurize the upper belt 54 and the lower belt 55 with a heat medium such as oil, for example.

By using the double belt press device 51, the metal-clad laminate 11 can be continuously obtained. By winding up the long metal-clad laminate 11, it is stored or transported as a roll product of the metal-clad laminate 11. The metal-clad laminate 11 can be used for, for example, a printed wiring board such as a flexible printed wiring board.

Next, the operation and effect of this embodiment will be described.
(1) The insulating layer 12 of the metal-clad laminate 11 includes a thermosetting polyimide layer 21 and a thermosetting resin layer 31 provided between the thermosetting polyimide layer 21 and the metal layer 13. The water absorption rate of the thermosetting resin layer 31 is lower than the water absorption rate of the thermosetting polyimide layer 21.

According to this configuration, by suppressing water absorption and dehydration of the heat-sealed resin layer 31 bonded to the metal layer 13, it is possible to suppress a change in the state of the interface between the metal layer 13 and the heat-sealed resin layer 31. Guessed. As a result, it is possible to suppress a decrease in the adhesiveness of the metal layer 13 to the insulating layer 12 having the thermosetting polyimide layer 21 in a long-term use accompanied by a temperature change. Further, since the insulating layer 12 has the thermosetting polyimide layer 21, the dimensional stability of the metal-clad laminate 11 can be easily ensured.

(2) The heat-sealed resin layer 31 preferably has a water absorption rate of 0.1% or less. In this case, it is possible to further suppress a decrease in the adhesiveness of the metal layer 13 to the insulating layer 12 having the thermosetting polyimide layer 21 in a long-term use accompanied by a temperature change.

(3) The heat-sealed resin layer 31 preferably has a melting point of 280 ° C. or higher. In this case, the solder heat resistance of the metal-clad laminate 11 can be easily increased.
(4) The metal layer 13 is preferably made of a metal foil having a ten-point average roughness (Rzjis) of 2.0 or less on the main surface to be adhered to the heat-sealed resin layer 31. In this case, by increasing the smoothness of the main surface of the metal foil, it is possible to suppress the skin effect in which the current in the high frequency band concentrates on the surface of the metal layer 13, so that the electrical characteristics in the high frequency band are sufficiently satisfied in the metal layer 13. Can be demonstrated.

(5) The coefficient of linear expansion of the thermosetting polyimide layer 21 is preferably in the range of 10 ppm / K or more and 26 ppm / K or less. In this case, the dimensional stability of the metal-clad laminate 11 can be improved.

(6) The heat-sealed resin layer 31 is preferably made of a fluororesin. In this case, since the dielectric constant of the insulating layer 12 can be suppressed to a low level, for example, the electrical characteristics in the high frequency band can be sufficiently exhibited.

(7) The peel strength of the metal layer 13 measured after the heat cycle test is preferably 80% or more when the peel strength of the metal layer 13 before the heat cycle test is 100%. As described above, it is possible to provide the metal-clad laminate 11 in which the deterioration of the adhesiveness of the metal layer 13 to the heat-sealed resin layer 31 is suppressed.

(8) The method for manufacturing the metal-clad laminate 11 is a thermoplastic method in which a thermosetting resin layer 31 is formed between a thermosetting polyimide film 121 to be a thermosetting polyimide layer 21 and a metal foil 113 to be a metal layer 13. It is provided with a step of heat-pressing the laminated body 111 on which the resin film 131 is arranged. In this case, the metal-clad laminate 11 can be efficiently manufactured. Further, in the step of thermocompression bonding the laminated body 111, the metal-clad laminate 11 can be continuously manufactured by using the double belt press device 51, so that the manufacturing efficiency of the metal-clad laminate 11 can be easily improved. be able to.

(Change example)
The above embodiment may be modified as follows. The above embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.

The metal-clad laminate 11 can also be manufactured by using a laminating device other than the double belt press device 51. Further, in the above embodiment, the long metal-clad laminate 11 is continuously manufactured, but the metal-clad laminate 11 having a predetermined size may be manufactured one by one.

-In the above embodiment, the metal-clad laminate 11 is manufactured by one-step thermocompression bonding, but it can also be manufactured by a plurality of steps of thermocompression bonding. For example, a metal-clad laminate 11 is manufactured by a step of obtaining a laminated film by heat-pressing a thermosetting polyimide film 121 and a thermoplastic resin film 131, and a step of heat-pressing the laminated film and a metal foil 113. You may.

In the metal-clad laminate 11, a laminated structure composed of a first heat-sealed resin layer 31a and a first metal layer 13a, and a laminated structure composed of a second heat-sealed resin layer 31b and a second metal layer 13b. Either one of the laminated structures may be omitted. That is, the metal-clad laminate has an insulating layer having a two-layer structure of a thermosetting polyimide layer and a thermosetting resin layer, and is a single-sided metal-clad laminate having a metal layer laminated on one side of the insulating layer. You may. In the case of a single-sided metal-clad laminate, the thickness of the insulating layer is preferably 5 μm or more, more preferably 10 μm or more, still more preferably 12.5 μm or more. In the case of a single-sided metal-clad laminate, the thickness of the insulating layer is preferably 200 μm or less, more preferably 150 μm or less, for example, from the viewpoint of further enhancing flexibility.

Next, Examples and Comparative Examples will be described.
(Example 1)
In Example 1, a metal-clad laminate in which metal layers were laminated on both sides of the insulating layer was manufactured. The thermosetting polyimide layer of the insulating layer is a thermosetting polyimide film (manufactured by Ube Kosan Co., Ltd., trade name: UPIREX-SGA) on which both sides are subjected to corona discharge treatment under the condition of a discharge amount of 155 W · min / m ² . Was formed using. Both the first heat-fused resin layer and the second heat-fused resin layer of the insulating layer were formed by using a fluorine-based resin film (manufactured by AGC Inc., trade name: EA-2000, melting point: 298 ° C.). The metal layer was formed by using a copper foil (manufactured by Mitsui Mining & Smelting Co., Ltd., trade name: TQ-M4-VSP). A double belt press device was used in the process of thermocompression bonding the film and the copper foil. Table 1 shows the physical characteristics of each layer and the conditions of thermocompression bonding.

The water absorption rates of the thermosetting polyimide layer and the thermosetting resin layer shown in Table 1 are based on JIS K7209: 2000 (ASTM D570), and the weight of the film forming each layer after being immersed in water at 23 ° C. for 24 hours. It is a value obtained from the measured value of the rate of change.

(Example 2)
In Example 2, similarly to Example 1, a metal-clad laminate in which metal layers were laminated on both sides of the insulating layer was manufactured. The thermosetting polyimide layer of Example 2 is a thermosetting polyimide film (manufactured by Ube Kosan Co., Ltd., trade name: UPIREX-S) different from that of Example 1 under the condition of a discharge amount of 520 W · min / m ² on both sides. It was formed by using a vacuum plasma discharge treatment. The first heat-fused resin layer and the second heat-fused resin layer of Example 2 are fluororesin films having different thicknesses from those of Example 1 (manufactured by AGC Inc., trade name: EA-2000, melting point: 298). ℃) was formed. The metal layer of Example 2 was formed by using the same copper foil as that of Example 1. In the step of thermocompression bonding the film and the copper foil, the same double belt press device as in Example 1 was used. Table 1 shows the physical characteristics of each layer and the conditions of thermocompression bonding.

(Example 3)
In Example 3, similarly to Example 1, a metal-clad laminate in which metal layers were laminated on both sides of the insulating layer was manufactured. The thermosetting polyimide layer of Example 3 is a thermosetting polyimide film (manufactured by Ube Kosan Co., Ltd., trade name: UPIREX-S) different from that of Example 1 under the condition of a discharge amount of 520 W · min / m ² on both sides. It was formed by using a vacuum plasma discharge treatment. The first heat-fused resin layer and the second heat-fused resin layer of Example 3 are fluororesin films having different thicknesses from those of Example 1 (manufactured by AGC Inc., trade name: EA-2000, melting point: 298). ℃) was formed. In Example 3, the metal layer was formed by using a copper foil having a ten-point average roughness (Rzjis) different from that of the copper foil of Example 1. In the step of thermocompression bonding the film and the copper foil, the same double belt press device as in Example 1 was used. Table 1 shows the physical characteristics of each layer and the conditions of thermocompression bonding.

(Comparative Example 1)
In Comparative Example 1, the thermosetting resin layer was omitted, and a metal-clad laminate in which a metal layer was laminated on both sides of the thermosetting polyimide layer was manufactured. The thermosetting polyimide layer of Comparative Example 1 uses a thermosetting polyimide film (manufactured by Ube Kosan Co., Ltd., trade name: Upirex-VT) having a different water absorption rate and the like from the thermosetting polyimide film of Example 1. Formed. The metal foil of Comparative Example 3 was formed by using the same copper foil as that of Example 1. In the step of thermocompression bonding the film and the copper foil, the same double belt press device as in Example 1 was used. Table 1 shows the physical characteristics of each layer and the conditions of thermocompression bonding.

(Comparative Example 2)
In Comparative Example 2, the thermosetting polyimide film was omitted, and a metal-clad laminate in which a metal layer was laminated on both sides of the thermosetting resin layer was manufactured. For the heat-sealed resin layer of Comparative Example 2, a fluorine-based resin film (manufactured by AGC Inc., trade name: EA-2000, melting point: 298 ° C.) having a thickness different from that of the fluorine-based resin film of Example 1 was used. Formed. The metal layer of Comparative Example 2 was formed by using the same copper foil as in Example 1. The step of thermocompression bonding the film and the copper foil was performed using the same double belt press device as in Example 1. Table 1 shows the physical characteristics of each layer and the conditions of thermocompression bonding.

<Peeling strength>
A sample is prepared by cutting the metal-clad laminate obtained in each example with a width dimension of 3 mm, and the peel strength of the metal layer is obtained by "Method A" (90 ° direction peeling method) specified in JIS C6471. Was measured. When the value of the peel strength of the metal layer was 0.6 N / mm or more, it was judged as good (◯), and when it was less than 0.6 N / mm, it was judged as defective (×). The results are shown in the "Peeling strength of metal layer (initial)" column in Table 1.

Further, after preparing a sample by cutting the metal-clad laminate obtained in each example with a width dimension of 3 mm, a heat cycle test of the sample was performed under the above-mentioned conditions.
The peel strength of the sample after the heat cycle test was measured, and the retention rate of the peel strength when the initial peel strength was 100% was calculated. When the retention rate of the peel strength was 80% or more, it was judged to be good (◯), and when the retention rate of the peel strength was less than 80%, it was judged to be defective (×). The results are shown in the "Peeling strength of metal layer (after heat cycle test)" column in Table 1.

<Dimensional change rate>
A sample was prepared by dividing the metal-clad laminate of each example into three pieces, the center in the width direction and both ends in the width direction, and cutting each piece to the dimensions of MD: 200 mm and TD: 160 mm. A plurality of 1 mmφ holes (mark points) were formed in each sample with an electric drill or a punch so as to be evenly spaced. The total number of reference points was 16, and the distance between the reference points was MD5 and TD5.

According to JIS C6471, the distances of 5 points in the MD direction and 5 points in the TD direction were measured, and the dimensional change rate was measured.
The dimensional change rate was measured after etching the metal layer and after heat treatment at 150 ° C. and 250 ° C., and judged according to the following criteria.

The dimensional change rate after etching was determined to be good (◯) within ± 0.10%, and defective (×) when it was outside the range of ± 0.10%. The results are shown in the "Dimensional change rate (after etching)" column in Table 1.

The dimensional change rate after heating at 150 ° C. was judged to be good (◯) when it was within ± 0.10%, and defective (×) when it was outside the range of ± 0.10%. The results are shown in the "Dimensional change rate (after heating at 150 ° C.)" column in Table 1.

The dimensional change rate after heating at 250 ° C. was judged to be good (◯) when it was within ± 0.15%, and defective (×) when it was outside the range of ± 0.15%. The results are shown in the "Dimensional change rate (after heating at 250 ° C.)" column in Table 1.

<Solder heat resistance test>
For the metal-clad laminates of each example, two samples at different positions in the TD direction were prepared, and a solder heat resistance test was performed according to JIS C6471. First, each sample was dried at 105 ° C. for 60 minutes or more, and then immediately immersed in a solder bath at 300 ° C. for 60 seconds. Next, after leaving the sample in a standard state for 1 hour, both sides of the sample were observed to confirm the presence or absence of abnormalities such as foaming and color unevenness. Those with no abnormality in the sample were judged to be good (◯), and those with abnormalities in the sample were judged to be defective (×). The results are shown in the "Solder heat resistance test" column in Table 1.

<High frequency transmission characteristics>
A sample was prepared in which a microstrip line having a circuit length of 100 mm and an impedance of 50 Ω was formed by etching the metal layer in the metal-clad laminate of each example. For this sample, an insertion loss (S21) of 40 GHz was measured with a network analyzer (manufactured by Keysight Technology, trade name: E8633B).

When the absolute value of the insertion loss (S21) is less than 0.4 dB / cm, the high frequency transmission characteristics are good (◯), and when it is 0.4 dB / cm or more and less than 0.5 dB / cm, the high frequency transmission characteristics are slightly inferior (◯). When it was 0.5 dB / cm or more, it was judged that the high frequency transmission characteristic was inferior (×). The results are shown in the "High frequency transmission characteristics" column in Table 1.

表１に示すように、実施例１～３では、ヒートサイクル試験後の金属層の剥離強度について良好な評価結果が得られることが分かる。また、実施例１～３では、寸法変化率についても良好な評価結果が得られることが分かる。

As shown in Table 1, it can be seen that in Examples 1 to 3, good evaluation results can be obtained for the peel strength of the metal layer after the heat cycle test. Further, in Examples 1 to 3, it can be seen that good evaluation results can be obtained with respect to the dimensional change rate.

In Examples 1 and 2, since the metal layer is formed by using a metal foil having a main surface having high smoothness, it can be seen that good evaluation results can be obtained also for high frequency transmission characteristics.
On the other hand, as shown in Comparative Example 1, it can be seen that when the heat-sealed resin layer is omitted, good evaluation results cannot be obtained for the peel strength after the heat cycle test. Further, as shown in Comparative Example 2, when the thermosetting polyimide layer was omitted, the obtained metal-clad laminate had a large warp, and the peel strength and the like could not be evaluated.

11 ... Metal-clad laminate 12 ... Insulation layer 13 ... Metal layer 21 ... Thermosetting polyimide layer 31 ... Heat-fused resin layer 111 ... Laminated 113 ... Metal leaf 121 ... Thermosetting polyimide film 131 ... Thermoplastic resin film

Claims (8)

A metal-clad laminate comprising an insulating layer and a metal layer laminated on one or both sides of the insulating layer.
The insulating layer includes a thermosetting polyimide layer and a thermosetting resin layer provided between the thermosetting polyimide layer and the metal layer.
A metal-clad laminate in which the water absorption rate of the thermosetting resin layer is lower than the water absorption rate of the thermosetting polyimide layer. The metal-clad laminate according to claim 1, wherein the heat-sealed resin layer has a water absorption rate of 0.1% or less. The metal-clad laminate according to claim 1 or 2, wherein the heat-sealed resin layer has a melting point of 280 ° C. or higher. Any one of claims 1 to 3, wherein the metal layer is composed of a metal foil having a ten-point average roughness (Rzjis) of 2.0 or less on the main surface to be adhered to the heat-sealed resin layer. The metal-clad laminate described in the section. The metal-clad laminate according to any one of claims 1 to 4, wherein the coefficient of linear expansion of the thermosetting polyimide layer is in the range of 10 ppm / K or more and 26 ppm / K or less. The metal-clad laminate according to any one of claims 1 to 5, wherein the heat-sealed resin layer is made of a fluororesin. The peel strength of the metal layer measured after performing a heat cycle test under the conditions that the temperature range is -50 ° C to 150 ° C, the holding time is 0 minutes, and the number of repeated temperature raising and lowering is 3000 times is determined. The metal-clad laminate according to any one of claims 1 to 6, wherein the peel strength of the metal layer before the heat cycle test is 80% or more. The insulating layer is provided with a metal layer laminated on one side or both sides of the insulating layer.
The insulating layer includes a thermosetting polyimide layer and a thermosetting resin layer provided between the thermosetting polyimide layer and the metal layer, and the water absorption rate of the thermosetting resin layer is thermosetting. A method for manufacturing a metal-clad laminate having a water absorption rate lower than that of the sex polyimide layer.
A step of thermally pressure-bonding a laminate in which a thermoplastic resin film to be a thermosetting resin layer is arranged between a thermosetting polyimide film to be a thermosetting polyimide layer and a metal foil to be a metal layer. A method for manufacturing a metal-clad laminate.

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