TW202224934A - Metal-clad laminate and method for manufacturing the same - Google Patents

Abstract

The present invention addresses the problem of providing: a metal-clad laminated board configured to be able to increase the adhesiveness between a heat-curable polyimide layer and a heat-fusible resin layer that is adhesive with respect to a metal layer; and a method for manufacturing the same. A metal-clad laminated board (11) comprises an insulating layer (12) and a metal layer (13) laminated on one side or both sides of the insulating layer (12). The insulating layer (12) comprises a heat-curable polyimide layer (21) and a heat-fusible resin layer (31) provided between the heat-curable polyimide layer (21) and the metal layer (13). The heat-curable polyimide layer (21) is composed of a heat-curable polyimide film in which the water contact angle on the main surface of the film, the main surface being configured to be bonded to the heat-fusible resin layer (31), is no more than 20 DEG.

Description

Metal-clad laminate and method of making the same

The present invention relates to a metal-clad laminate and a manufacturing method thereof.

In recent years, with the utilization of the Internet of Things (Internet of Things), there is a tendency to use electronic devices such as sensors in various environments. For example, the ultra-high frequency used in sensors, etc., has high stability to light, weather, and environment, so in addition to the ultra-high frequency radar used in automobiles, it is also assumed to be used in harsh environments. Therefore, in recent years, electronic devices are sometimes used in harsh environments, and along with this, improvement in the environmental resistance performance of electronic devices is currently being sought. In this regard, a printed circuit board equipped with electronic equipment is a metal-clad laminate having a laminate structure formed of a polyimide layer as an insulating layer and a copper layer as a metal layer. For example, Patent Document 1 discloses a polyimide film suitable for a polyimide layer of a metal-clad laminate.

prior art literature Patent Literature Patent Document 1: Japanese Patent Laid-Open No. 2008-106137

The problem to be solved by the invention In the metal-clad laminate as described above, by disposing the heat-sealing resin layer between the thermosetting polyimide layer and the metal layer, the insulating layer and the metal layer having the thermosetting polyimide layer and the heat-sealing resin layer can be improved. Bondability between layers. Therefore, there is still room for improvement in the bondability between the thermal fusion resin layer having bondability to the metal layer and the thermosetting polyimide layer.

means of solving problems An aspect of the present invention for solving the above-mentioned problems provides a metal-clad laminate including an insulating layer and a metal layer laminated on one side or both sides of the insulating layer. The insulating layer includes a thermosetting polyimide layer and a thermal fusion resin layer provided between the thermosetting polyimide layer and the metal layer, and the thermosetting polyimide layer is mainly composed of a main material bonded to the thermal fusion resin layer. The water contact angle of the surface is composed of a thermosetting polyimide film with a water contact angle of 20° or less.

According to this configuration, since the main surface of the thermosetting polyimide film bonded to the heat-sealing resin layer is in a state of being easily hydrogen-bonded, for example, the bonding force between the thermosetting polyimide layer and the heat-sealing resin layer can be improved.

In the above-mentioned metal-clad laminate, it is preferable that the above-mentioned thermosetting polyimide layer contains 3,3',4,4'-biphenyltetracarboxylic dianhydride and p-phenylenediamine as copolymerization components. According to this configuration, excellent low dielectric properties can be exhibited.

In the above-mentioned metal-clad laminate, it is preferable that the above-mentioned thermal fusion resin layer 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 improved.

In the above-mentioned metal-clad laminate, it is preferable that the above-mentioned metal layer is formed of a metal foil having a ten-point average roughness (Rzjis) of a main surface bonded to the above-mentioned thermal fusion resin layer of 2.0 or less. According to this configuration, since the smoothness of the main surface of the metal foil is improved, the skin effect in which the current in the high frequency band is concentrated on the surface of the metal layer can be suppressed, so that the electronic characteristics of the high frequency band in the metal layer can be fully exhibited.

In the metal-clad laminate, it is preferable that the linear expansion coefficient of the thermosetting polyimide layer is 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 above-mentioned metal-clad laminate, it is preferable that the water absorption rate of the thermal fusion resin layer is lower than the water absorption rate of the thermosetting polyimide layer. According to this configuration, it is presumed that by suppressing water absorption or dehydration of the heat-sealing resin layer bonded to the metal layer, the state of the interface between the metal layer and the heat-sealing resin layer can be suppressed from changing. In this way, it is possible to suppress a decrease in the bondability of the metal layer to the insulating layer having the thermosetting polyimide layer under long-term use with temperature change.

In the above-mentioned metal-clad laminate, it is preferable that the peel strength between the above-mentioned thermosetting polyimide layer and the above-mentioned thermal fusion resin layer is 0.6 N/mm or more.

In the above-mentioned metal-clad laminate, it is preferable that the above-mentioned thermal fusion resin layer is formed of a fluorine-based resin. According to this configuration, since the permittivity of the insulating layer can be reduced, for example, the electronic characteristics of the high frequency band can be sufficiently exhibited.

In the above-mentioned metal-clad laminate, it is preferable that the above-mentioned thermosetting polyimide layer is formed of a thermosetting polyimide film disposed on the main surface on the side of the heat-sealing resin layer and subjected to discharge treatment, and X-ray photoelectric spectroscopy is used. In the surface analysis of the thermosetting polyimide film by the analytical method, from the accumulated value A1 of 527 to 536 eV before the discharge treatment and the accumulated value A2 of 527 to 536 eV after the discharge treatment, it was calculated by the following formula (1) The ratio R is 1.35 or more. R=A2/A1・・・（1）

In the above-mentioned metal-clad laminate, it is preferable that the above-mentioned thermosetting polyimide layer is formed of a thermosetting polyimide film disposed on the main surface on the side of the heat-sealing resin layer and subjected to discharge treatment, and X-ray photoelectric spectroscopy is used. In the surface analysis of the above-mentioned thermosetting polyimide film of the analytical method, the sum of the accumulated values of 278 to 298 eV, 391 to 411 eV, 523 to 543 eV, and 94 to 114 eV was taken as 100%, and the total of 100% was taken into account. When the ratio occupied by the integrated value of 523 to 543 eV is set as the content of oxygen atoms, the following formula is obtained from the content B1 (%) of oxygen atoms before the above-mentioned discharge treatment and the content of oxygen atoms after the above-mentioned discharge treatment B2 (%) (2) The calculated change amount C (%) of oxygen atoms is 5% or more. C（%）＝B2-B1・・・（2）

Another aspect of the present invention provides a method for producing a metal-clad laminate including an insulating layer and a metal layer laminated on one side or both sides of the insulating layer. The insulating layer includes a thermosetting polyimide layer and a thermal fusion resin layer provided between the thermosetting polyimide layer and the metal layer, and the thermosetting polyimide layer is mainly composed of a main material bonded to the thermal fusion resin layer. The water contact angle of the surface is composed of a thermosetting polyimide film with a water contact angle of 20° or less. The method for producing a metal-clad laminate preferably includes a step of arranging a laminate in which the thermoplastic resin film as the heat-fusible resin layer is disposed between the thermosetting polyimide film and the metal foil as the metal layer. Perform thermocompression bonding.

Invention effect ADVANTAGE OF THE INVENTION According to this invention, the adhesiveness between the heat fusion resin layer which has adhesiveness to a metal layer, and a thermosetting polyimide layer can be improved.

Hereinafter, one embodiment of the metal-clad laminate and its manufacturing method will be described. However, the thickness of each layer constituting the metal-clad laminate may be exaggerated in the drawings.

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 13 a laminated on one main surface of the insulating layer 12 and a second metal layer 13 b laminated on the other main surface of the insulating layer 12 .

The insulating layer 12 includes a thermosetting polyimide layer 21 and a thermal fusion resin layer 31 . The thermal fusion resin layer 31 is composed of a first thermal fusion resin layer 31a provided between the thermosetting polyimide layer 21 and the first metal layer 13a and a thermal fusion resin layer 31a provided between the thermosetting polyimide layer 21 and the second metal layer 13b The second heat-sealing resin layer 31b is formed. Therefore, the metal-clad laminate 11 of the present embodiment is a double-sided metal-clad laminate having a five-layer structure, and has a thermosetting polyimide layer 21 , a first thermal fusion resin layer 31 a , and a second thermal fusion resin layer. The insulating layer 12 having a three-layer structure constituted by 31b has a metal layer 13 laminated on both sides of the insulating layer 12, respectively.

<Thermosetting polyimide layer 21> The thermosetting polyimide layer 21 is composed of a thermosetting polyimide film having a water contact angle of a main surface bonded to the thermal fusion resin layer 31 of 20° or less. The water contact angle of the main surface of the thermosetting polyimide film is preferably 17° or less, more preferably 14° or less. From the viewpoint of productivity and the like, the water contact angle of the main surface of the thermosetting polyimide film is preferably, for example, 5° or more, and more preferably 6° or more. A thermosetting polyimide film having a main surface with a water contact angle of 20° or less can be obtained, for example, by subjecting the main surface of the thermosetting polyimide film to discharge treatment. That is, a hydrophilic group can be introduced into the main surface of the thermosetting polyimide film by discharge treatment. Therefore, the water contact angle of the main surface of the thermosetting polyimide film can be reduced by the introduced hydrophilic group.

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. The diamine component includes p-phenylenediamine (PPD), 4,4-diaminodiphenyl ether, m-toluidine, 4,4'-diaminobenzylaniline, and the like. As a commercial item of a thermosetting polyimide film, UPILEX-S (trade name), UPILEX-SGA (trade name) by Ube Kosan Co., Ltd., etc. are mentioned, for example.

From the viewpoint of excellent low dielectric properties such as low permittivity and low dielectric tangent, the thermosetting polyimide layer 21 preferably contains 3,3',4,4'-biphenyltetracarboxylic dianhydride and para- Phenylenediamine is used as a copolymerization component. When the total acid component is set to 100 mol%, the content of 3,3',4,4'-biphenyltetracarboxylic dianhydride in the thermosetting polyimide layer 21 is preferably 50 mol% or more, more preferably is more than 70 mol%. When the entire diamine component is set to 100 mol %, the content of p-phenylenediamine in the thermosetting polyimide layer 21 is preferably 50 mol % or more, more preferably 70 mol % or more. Among them, commercial products of thermosetting polyimide films containing 3,3',4,4'-biphenyltetracarboxylic dianhydride and p-phenylenediamine as copolymerization components include, for example, Ube Industries Co., Ltd. Made UPILEX-SGA (trade name).

The discharge treatment of the thermosetting polyimide film includes, for example, corona discharge treatment, atmospheric pressure plasma discharge treatment, vacuum plasma discharge treatment, and the like. Among the discharge treatments, the corona discharge treatment is preferred from the viewpoint of reducing facility cost and improving productivity. The conditions of the discharge treatment may be adjusted so that the water contact angle of the main surface of the thermosetting polyimide film can be adjusted to the above-mentioned value. For example, in the corona discharge treatment, the discharge amount can be set in the range of 20 W·min/m ² or more and 500 W·min/m ² or less.

In a thermosetting polyimide film having a main surface with a water contact angle of 20° or less, oxygen atoms are detected by hydrophilic groups in surface analysis using X-ray photoelectron spectroscopy (XPS: X-ray Photoelectron Spectroscopy). In the surface analysis of the thermosetting polyimide film using this XPS, the ratio calculated by the following formula (1) from the cumulative value A1 of 527 to 536 eV before the discharge treatment and the cumulative value A2 of 527 to 536 eV after the discharge treatment R is preferably 1.35 or more. R=A2/A1・・・（1）

In the surface analysis of the thermosetting polyimide film using XPS, the content of oxygen atoms can be expressed based on the total of carbon atoms, nitrogen atoms, oxygen atoms, and silicon atoms. That is, the total of the respective accumulated values of 278 to 298 eV (carbon atom), 391 to 411 eV (nitrogen atom), 523 to 543 eV (oxygen atom), and 94 to 114 eV (silicon atom) is assumed to be 100%. The proportion occupied by the accumulated value of 523 to 543 eV (oxygen atoms) in the total 100% can be expressed as the content of oxygen atoms. The amount of change C (%) of oxygen atoms calculated by the following formula (2) from the content B1 (%) of oxygen atoms before the discharge treatment and the content B2 (%) of oxygen atoms after the discharge treatment is preferably 5% above. C（%）＝B2-B1・・・（2）

The thickness of the thermosetting polyimide layer 21 is preferably, for example, 125 μm or less. 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.

<Thermal fusion resin layer 31> The water absorption rate of the thermal fusion resin layer 31 is preferably lower than that of the thermosetting polyimide layer 21, more preferably 0.1% or less, further 0.07% or less, and most preferably 0.05% or less.

From the viewpoint of easily improving the solder heat resistance, the thermal fusion resin layer 31 preferably has a melting point of 280° C. or higher, for example. On the other hand, from the viewpoint of the ease of thermal fusion, the melting point of the thermal fusion resin layer 31 is preferably 320° C. or lower.

The thickness of the first heat-sealing resin layer 31a and the thickness of the second heat-sealing resin layer 31b are preferably 5 μm or more, more preferably 10 μm or more, and most preferably 12.5 μm or more. The thickness of the first heat-sealing resin layer 31a and the thickness of the second heat-sealing resin layer 31b are preferably 150 μm or less, more preferably 120 μm or less, and most preferably 100 μm or less. The thickness of the first thermal fusion resin layer 31a and the thickness of the second thermal fusion resin layer 31b may be the same or different. The difference between the thickness of the first heat-sealing resin layer 31a and the thickness of the second heat-sealing resin layer 31b is preferably 3 μm or less, and more preferably 2 μm or less, from the viewpoint of suppressing distortion or warpage of the metal-clad laminate 11 , the best is 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, and most preferably 25 μm or more. From the viewpoint of further improving flexibility, the thickness of the insulating layer 12 of the present embodiment is preferably, for example, 400 μm or less, and more preferably 300 μm or less.

From the viewpoint of lowering the permittivity, the thermal fusion resin layer 31 is preferably composed of, for example, a fluorine-based resin. From the viewpoint of having good low dielectric properties or good bonding properties, among fluorine-based resins, tetrafluoroethylene-hexafluoropropylene copolymer (FEP), or tetrafluoroethylene-perfluoroalkyl vinyl ether Copolymers (PFA) are preferred.

<Metal layer 13> The metal of the metal layer 13 includes, for example, gold, silver, copper, copper alloy, aluminum, aluminum alloy, and the like. The first metal layer 13a and the second metal layer 13b may be formed of the same metal, or may be formed of different metals. The metal layer 13 can be formed using, for example, copper foil. As a copper foil, an electrolytic copper foil and a rolled copper foil are mentioned, for example. 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 within a range of 2 μm or more and 105 μm or less, and more preferably within a range of 2 μm or more and 35 μm or less. The thickness of the first metal layer 13a and the thickness of the second metal layer 13b may be the same thickness or different thicknesses.

Here, the rougher the surface roughness of the main surface of the metal foil bonded to the thermal fusion resin layer 31 is, the higher the bonding strength between the metal layer 13 and the thermal fusion resin layer 31 tends to be. On the other hand, if the main surface of the metal foil is relatively smooth, the skin effect in which the current in the high frequency band is concentrated on the surface of the metal layer 13 can be suppressed, whereby the electronic characteristics of the high frequency band can be fully exhibited. In recent years, with the increase in frequency of electronic devices such as 5G smartphones, the demand for printed circuit boards with smaller transmission loss has gradually increased. Therefore, when the metal-clad laminate 11 is used as a printed circuit board corresponding to a high frequency band, the metal layer 13 preferably has a ten-point average roughness (Rzjis) of the principal surface bonded to the thermal fusion resin layer 31 of 2.0 or less. Made of metal foil. The ten-point average roughness (Rzjis) is specified in JIS B0601 (2001). JIS B0601 corresponds to ISO4287. The ten-point average roughness (Rzjis) of the main surface of the metal foil is more preferably 1.5 or less, and most preferably 1.0 or less.

<Linear expansion coefficient and peel strength> By making the linear expansion coefficient of the insulating layer 12 approach the linear expansion coefficient 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 18ppm/K. When the metal layer 13 is a copper layer, the linear expansion coefficient 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 linear expansion coefficient 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 if the coefficient of linear expansion of the thermal fusion resin layer 31 is larger than the coefficient of linear expansion of the thermosetting polyimide layer 21, by setting the coefficient of linear expansion of the thermosetting polyimide layer 21 within the above-mentioned range, the metal coating can be made. The dimensional stability of the laminate 11 is improved.

The peel strength between the thermosetting polyimide layer 21 and the thermal fusion resin layer 31 is preferably 0.6 N/mm or more.

<Manufacturing method of metal-clad laminate 11 > Next, the manufacturing method of the metal-clad laminate 11 will be described.

As shown in FIG. 2 , the method of manufacturing the metal-clad laminate 11 includes a step of thermocompression bonding of the laminate 111 in which the thermoplastic resin film 131 is arranged between the thermosetting polyimide film 121 and the metal foil 113 . The thermosetting polyimide film 121 forms the above-described thermosetting polyimide layer 21 . The first thermoplastic resin film 131a and the second thermoplastic resin film 131b form the first heat-sealing resin layer 31a and the 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 of the laminated body 111, the laminated body 111 is heated so that the thermoplastic resin film 131 has a temperature equal to or higher than the melting point. When the melting point of the thermoplastic resin film 131 is set to Tm°C, the maximum temperature in the step of thermocompression bonding of the laminate 111 is preferably Tm+70°C or lower.

The pressure in the step of thermocompression bonding the laminated body 111 is preferably, 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.

The heating time in the step of thermocompression bonding of the laminated body 111 is preferably within a range of, for example, 10 seconds or more and 600 seconds or less, and more preferably within a range of 30 seconds or more and 500 seconds or less.

In the step of thermocompression bonding of the laminated body 111 , it is preferable to use the double belt press apparatus 51 . The double belt press apparatus 51 is heated and pressurized while conveying the laminated body 111 . The double belt press apparatus 51 has a first conveyance part 52 located on the upstream side in the conveyance direction of the layered body 111 and a second conveyance part 53 located on the downstream side.

The 1st conveyance part 52 is equipped with the upper side 1st roller 52a and the lower side 1st roller 52b. The 2nd conveyance part 53 is equipped with the upper side 2nd roller 53a and the lower side 2nd roller 53b. The upper side 1st roller 52a and the upper side 2nd roller 53a are stretched by the endless upper side belt 54. As shown in FIG. The endless lower belt 55 is stretched over the lower first roller 52b and the lower second roller 53b. Moreover, each 1st roller 52a, 52b is comprised so that it may be driven by each 2nd roller 53a, 53b through each belt 54, 55, and is driven. Each of the belts 54 and 55 is formed of metal such as stainless steel, for example.

An upper temperature adjustment device 56 and a lower temperature adjustment device 57 are arranged between the first conveyance portion 52 and the second conveyance portion 53 , and are interposed between the belts 54 and 55 to face each other. The upper temperature adjustment device 56 and the lower temperature adjustment device 57 heat and pressurize the layered body 111 via the upper belt 54 and the lower belt 55 . The upper temperature adjustment device 56 and the lower temperature adjustment device 57 heat and pressurize the upper belt 54 and the lower belt 55 by a heat medium such as oil, for example.

The metal-clad laminate 11 can be continuously obtained by using the double belt pressing device 51 . The elongated metal-clad laminate 11 is wound up and stored or transported as a cylinder of the metal-clad laminate 11 . The metal-clad laminate 11 can be used for printed circuit boards such as flexible printed circuit boards.

Next, the action and effect of the present embodiment will be described.

(1) The insulating layer 12 of the metal-clad laminate 11 includes a thermosetting polyimide layer 21 and a thermal fusion resin layer 31 provided between the thermosetting polyimide layer 21 and the metal layer 13 . The thermosetting polyimide layer 21 is composed of a thermosetting polyimide film 121 having a water contact angle of a main surface bonded to the thermal fusion resin layer 31 of 20° or less.

According to this configuration, since the main surface of the thermosetting polyimide film 121 bonded to the heat-sealing resin layer 31 is in a state of being easily hydrogen-bonded, for example, the interlayer between the thermosetting polyimide layer 21 and the heat-sealing resin layer 31 can be improved. binding force. In this way, the adhesiveness between the thermal fusion resin layer 31 having adhesiveness to the metal layer 13 and the thermosetting polyimide layer 21 can be improved.

(2) The thermosetting polyimide layer 21 preferably contains 3,3',4,4'-biphenyltetracarboxylic dianhydride and p-phenylenediamine as copolymerization components. In this case, excellent low dielectric properties can be exhibited.

(3) The thermal fusion 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 improved.

(4) The metal layer 13 is preferably composed of a metal foil having a ten-point average roughness (Rzjis) of the main surface bonded to the thermal fusion resin layer 31 of 2.0 or less. At this time, since the smoothness of the main surface of the metal foil is improved, the skin effect in which the current in the high frequency band is concentrated on the surface of the metal layer 13 can be suppressed, so that the electronic characteristics of the high frequency band in the metal layer 13 can be fully exhibited.

(5) The linear expansion coefficient 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 water absorption rate of the thermal fusion resin layer 31 is preferably lower than the water absorption rate of the thermosetting polyimide layer 21 . At this time, it is estimated that the state change of the interface between the metal layer 13 and the thermal fusion resin layer 31 can be suppressed by suppressing water absorption or dehydration of the thermal fusion resin layer 31 bonded to the metal layer 13 . In this way, it is possible to suppress a decrease in the adhesion of the metal layer 13 to the insulating layer 12 having the thermosetting polyimide layer 21 under long-term use with temperature changes.

(7) The peel strength between the thermosetting polyimide layer 21 and the thermal fusion resin layer 31 is preferably 0.6 N/mm or more. Therefore, the bondability between the thermosetting polyimide layer 21 and the thermal fusion resin layer 31 can be ensured.

(8) The thermal fusion resin layer 31 is preferably made of a fluorine-based resin. At this time, since the permittivity of the insulating layer 12 can be lowered, for example, the electronic characteristics of the high frequency band can be sufficiently exhibited.

(9) In the surface analysis of the thermosetting polyimide film 121 using X-ray photoelectric spectrometry, calculated from the above-mentioned accumulated value A1 of 527 to 536 eV before the discharge treatment and the accumulated value A2 of 527 to 536 eV after the discharge treatment The ratio R is preferably 1.35 or more. Therefore, the thermosetting polyimide film 121 modified by the discharge treatment can be used as the thermosetting polyimide layer 21 .

(10) Calculated from the content B1 (%) of oxygen atoms before the discharge treatment and the content of oxygen atoms after the discharge treatment B2 (%) in the surface analysis of the thermosetting polyimide film by X-ray photoelectric spectrometry The amount of change C (%) of the oxygen atoms in , is preferably 5% or more. Therefore, the thermosetting polyimide film 121 modified by the discharge treatment can be used as the thermosetting polyimide layer 21 .

(11) A method of manufacturing the metal-clad laminate 11 , which includes the step of disposing a thermal film between the thermosetting polyimide film 121 as the thermosetting polyimide layer 21 and the metal foil 113 as the metal layer 13 . The laminated body 111 of the thermoplastic resin film 131 of the fusion resin layer 31 is thermocompression-bonded. In this case, the metal-clad laminate 11 can be efficiently produced. In addition, in the step of thermocompression bonding of the laminated body 111 , since the metal-clad laminated board 11 can be continuously manufactured by using the double belt press apparatus 51 , the manufacturing efficiency of the metal-clad laminated board 11 can be easily improved.

(change example) The above-described embodiment may be modified in the following manner. The above-described embodiment and the following modifications can be implemented in combination with each other within a technically non-contradictory range.

・The metal-clad laminate 11 can also be produced using a laminate apparatus other than the double belt press apparatus 51 or the like. Further, in the above-described embodiment, the elongated metal-clad laminate 11 is continuously manufactured, but a metal-clad laminate of a predetermined size may be manufactured piece by piece.

- In the above-described embodiment, the metal-clad laminate 11 is manufactured by one-stage thermocompression bonding, but it may also be manufactured by multi-stage thermocompression bonding. For example, the metal-clad laminate can also be produced by a step of thermocompression bonding of the thermosetting polyimide film 121 and the thermoplastic resin film 131 to obtain a laminate film, and a step of thermocompression bonding of the laminate film and the metal foil 113 . board 11.

・In the above-mentioned metal-clad laminate 11, the laminate structure composed of the first thermal fusion resin layer 31a and the first metal layer 13a, and the laminate structure composed of the second thermal fusion resin layer 31b and the second metal layer 13b may be omitted The laminated structure of any one of the laminated structures. That is to say, the metal-clad laminate can also be a single-sided metal-clad laminate, that is, an insulating layer with a two-layer structure of a thermosetting polyimide layer and a heat-sealing resin layer, and a single-layer laminate on the insulating layer. surface metal layer. 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, and most preferably 12.5 μm or more. In the case of a single-sided metal-clad laminate, from the viewpoint of further improving flexibility, the thickness of the insulating layer is preferably, for example, 200 μm or less, and more preferably 150 μm or less.

Example

Next, Examples and Comparative Examples will be described.

(Example 1) In Example 1, a double-area metal-clad laminate with an insulating layer was produced. The thermosetting polyimide layer of the insulating layer is composed of a thermosetting polyimide film with a water contact angle of 12° on the two main surfaces. The thermosetting polyimide film was obtained by discharging a commercially available thermosetting polyimide film (manufactured by Ube Industries, Ltd., trade name: UPILEX-SGA). The discharge treatment was a corona discharge treatment with a discharge amount of 155 W·min/m ² .

Both the first heat-sealing resin layer and the second heat-sealing resin layer of the insulating layer were formed using a fluororesin film (manufactured by AGC Co., Ltd., trade name: EA-2000). The metal layer was formed using copper foil (manufactured by Mitsui Metal Mining Co., Ltd., trade name: TQ-M4-VSP). The step of thermocompression-bonding the film and the copper foil is to use a double tape press device.

Table 1 shows the physical properties of each layer and the conditions for thermocompression bonding.

The "water contact angle" shown in Table 1 was measured by the droplet method using a contact angle meter (manufactured by Kyowa Interface Science Co., Ltd., trade name: DMs-401) on the thermosetting polyimide film after discharge treatment 3 average value of times.

In addition, surface analysis of the thermosetting polyimide film before and after discharge treatment was performed using X-ray photoelectron spectroscopy (XPS). The surface analysis was performed using an X-ray photoelectric spectroscopic analyzer (manufactured by ULVAC・PHI Co., Ltd., trade name: PHI 5000 Versa Probe II). In addition, the X-ray source for surface analysis was AlKα line (1486.6 eV).

In the surface analysis of the thermosetting polyimide film using XPS, the ratio R was calculated by the above formula (1) from the accumulated value A1 of 527 to 536 eV before the discharge treatment and the accumulated value A2 of 527 to 536 eV after the discharge treatment. In Table 1, in the column "Amount of increase of oxygen atoms", the ratio R was shown as "◯" when the ratio R was 1.35 or more, and was shown as "x" when the ratio R was less than 1.35.

In addition, in the surface analysis of the thermosetting polyimide film using XPS, oxygen atom content B1 (%) before discharge treatment and oxygen atom content B2 (%) after discharge treatment were calculated by the following (2) Atomic change C (%). The results are shown in the column of "change amount of oxygen atom" in Table 1.

The water absorption rates of the thermosetting polyimide layer and the heat-sealing resin layer shown in Table 1 were measured according to JIS K7209:2000 (ASTM D570), from the measurement of the weight change rate after immersing the film forming each layer in water at 23°C for 24 hours The value sought. JIS K7209:2000 corresponds to ISO62:1999.

(Example 2) In Example 2, a metal-clad laminate was produced in the same manner as in Example 1, except that the thicknesses of the first heat-sealing resin layer and the second heat-sealing resin layer were changed. For the step of thermocompression bonding of the film and the copper foil, the same double tape press apparatus as in Example 1 was used. Table 1 shows the physical properties of each layer and the conditions for thermocompression bonding.

(Example 3) In Example 3, the thermosetting polyimide layer other than the insulating layer was composed of a thermosetting polyimide film having a water contact angle of 8° on both main surfaces, and the first thermal fusion resin layer and A metal-clad laminate was produced in the same manner as in Example 1 except that the thickness of the second thermal fusion resin layer was changed. The thermosetting polyimide film was obtained by discharging a commercially available thermosetting polyimide film (manufactured by Ube Industries, Ltd., trade name: UPILEX-SGA). The discharge treatment was a corona discharge treatment with a discharge amount of 200 W·min/m ² . For the step of thermocompression bonding of the film and the copper foil, the same double tape press apparatus as in Example 1 was used. Table 1 shows the physical properties of each layer and the conditions for thermocompression bonding.

(Example 4) Example 4 is the same as Example 1, except that the thermosetting polyimide layer of the insulating layer is composed of a thermosetting polyimide film with a water contact angle of 15° on the two main surfaces. Metal clad laminates were fabricated in the same manner. The thermosetting polyimide film was obtained by discharging a commercially available thermosetting polyimide film (manufactured by Ube Industries, Ltd., trade name: UPILEX-SGA). The discharge treatment was a corona discharge treatment with a discharge amount of 310 W·min/m ² . For the step of thermocompression bonding of the film and the copper foil, the same double tape press apparatus as in Example 1 was used. Table 1 shows the physical properties of each layer and the conditions for thermocompression bonding.

(Example 5) In Example 5, the thermosetting polyimide layer other than the insulating layer was composed of a thermosetting polyimide film with a water contact angle of 18° on both main surfaces and a thickness of 25 μm, and the first heat A metal-clad laminate was produced in the same manner as in Example 1, except that the thicknesses of the fusion resin layer and the second heat fusion resin layer were changed. The thermosetting polyimide film was obtained by discharging a commercially available thermosetting polyimide film (manufactured by Ube Industries, Ltd., trade name: UPILEX-SGA). The discharge treatment was a corona discharge treatment with a discharge amount of 155 W·min/m ² . For the step of thermocompression bonding of the film and the copper foil, the same double tape press apparatus as in Example 1 was used. Table 1 shows the physical properties of each layer and the conditions for thermocompression bonding.

(Example 6) In Example 6, a metal-clad laminate was produced in the same manner as in Example 1, except that the metal layer was formed using a copper foil having a ten-point average roughness (Rzjis) different from that of the copper foil of Example 1. For the step of thermocompression bonding of the film and the copper foil, the same double tape press apparatus as in Example 1 was used. The physical properties of each layer and the conditions of thermocompression bonding are shown in Table 2.

(Comparative Example 1) In Comparative Example 1, except that the thermosetting polyimide layer of the insulating layer is composed of a thermosetting polyimide film with a water contact angle of 24° on both main surfaces, the rest is the same as that of Example 1. way to manufacture metal-clad laminates. The thermosetting polyimide film was obtained by discharging a commercially available thermosetting polyimide film (manufactured by Ube Industries, Ltd., trade name: UPILEX-S). The discharge treatment was a corona discharge treatment with a discharge amount of 155 W·min/m ² . For the step of thermocompression bonding of the film and the copper foil, the same double tape press apparatus as in Example 1 was used. The physical properties of each layer and the conditions of thermocompression bonding are shown in Table 2.

(Comparative Example 2) In Comparative Example 2, the thermosetting polyimide layer other than the insulating layer was composed of a thermosetting polyimide film having a water contact angle of 29° on both main surfaces, and the first thermal fusion resin layer and A metal-clad laminate was produced in the same manner as in Example 1 except that the thickness of the second thermal fusion resin layer was changed. The thermosetting polyimide film was obtained by discharging a commercially available thermosetting polyimide film (manufactured by Ube Industries, Ltd., trade name: UPILEX-VT). The discharge treatment was a corona discharge treatment with a discharge amount of 155 W·min/m ² . For the step of thermocompression bonding of the film and the copper foil, the same double tape press apparatus as in Example 1 was used. The physical properties of each layer and the conditions of thermocompression bonding are shown in Table 2.

(Comparative Example 3) In Comparative Example 3, the thermosetting polyimide layer other than the insulating layer was composed of a thermosetting polyimide film having a water contact angle of 79.5° on both main surfaces, and the first thermal fusion resin layer and the second thermal fusion resin were used. A metal-clad laminate was produced in the same manner as in Example 1 except that the thickness of the layers was changed. The thermosetting polyimide film is a commercially available thermosetting polyimide film (manufactured by Ube Industries, Ltd., trade name: UPILEX-SGA). For the step of thermocompression bonding of the film and the copper foil, the same double tape press apparatus as in Example 1 was used. The physical properties of each layer and the conditions of thermocompression bonding are shown in Table 2.

(Comparative Example 4) In Comparative Example 4, a metal was produced in the same manner as in Example 1, except that the thermosetting polyimide layer of the insulating layer was composed of a thermosetting polyimide film having a water contact angle of 76° on both main surfaces. Clad laminate. The thermosetting polyimide film is a commercially available thermosetting polyimide film (manufactured by Ube Industries, Ltd., trade name: UPILEX-S). For the step of thermocompression bonding of the film and the copper foil, the same double tape press apparatus as in Example 1 was used. The physical properties of each layer and the conditions of thermocompression bonding are shown in Table 2.

<Appearance inspection> A sample of 500 mm×500 mm was taken from the metal-clad laminate obtained in each example, and the appearance of the sample was visually observed. Those with no wrinkles on the sample were judged to be good (○), and those with wrinkles on the sample were judged to be poor (x). The results are shown in the column of "Appearance Inspection" in Tables 1 and 2.

<Peel Strength> The metal-clad laminate obtained in each example was cut into a square shape with a width of 10 mm to prepare a sample, and the thermosetting polyimide layer was measured by "method A" (peeling method in the 90° direction) specified in JIS C6471. Peel strength between layers with thermal fusion resin layers. JIS C6471-1995 corresponds to IEC249-1 (1982). When the value of the peel strength 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 poor (×). The results are shown in the column of "peel strength" in Tables 1 and 2.

<Transmission characteristics of high frequency> A sample was prepared, and the metal layer in the metal-clad laminate of each example was etched to form a microstrip line with a circuit length of 100 mm and an impedance of 50Ω. For this sample, the insertion loss at 40 GHz was measured with a network analyzer (manufactured by Keysight Technologies, trade name: E8363B) ( S21 ).

When the absolute value of the insertion loss (S21) is less than 0.4dB/cm, it is judged that the transmission characteristics of high frequency are good (○), and that the absolute value of insertion loss (S21) is less than 0.4dB/cm, and it is judged that the transmission characteristics of high frequency are slightly poor ( △), and the case of 0.5dB/cm or more was judged to be poor in high-frequency transmission characteristics (×). The results are shown in the column "Transmission characteristics of high frequency" in Tables 1 and 2.

Table 1 Example 1 Example 2 Example 3 Example 4 Example 5 Insulation Thermoset Polyimide Layer Water contact angle [°] 12 12 8 15 18 increase in oxygen atoms ○ ○ ○ ○ ○ Change of oxygen atom [%] 5.7 5.7 5.9 5.4 5.1 Water absorption [%] 1.4 1.4 1.4 1.4 1.2 Linear expansion coefficient [ppm/K] 14 14 14 14 13 Thickness [μm] 50 50 50 50 25 Thermal fusion resin layer Thickness [μm] 25 12.5 12.5 25 12.5 Water absorption [%] 0.01 0.01 0.01 0.01 0.01 metal layer Thickness [μm] 12 12 12 12 12 Rzjis[μm] 0.5 0.5 0.5 0.5 0.5 Conditions for thermocompression bonding Maximum temperature [℃] 330 330 330 330 330 Pressure [N/mm ² ] 4.0 4.0 4.0 4.0 4.0 Heating time [seconds] 210 210 210 210 175 Visual inspection ○ ○ ○ ○ ○ peel strength ○ ○ ○ ○ ○ High frequency transmission characteristics ○ ○ ○ ○ ○

Table 2 Example 6 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Insulation Thermoset Polyimide Layer Water contact angle [°] 12 twenty four 29 79.5 76 increase in oxygen atoms ○ × × - - Change of oxygen atom [%] 5.7 4.65 5.4 - - Water absorption [%] 1.4 1.4 1.4 1.4 1.4 Linear expansion coefficient [ppm/K] 14 16 20 14 16 Thickness [μm] 50 50 50 50 50 Thermal fusion resin layer Thickness [μm] 25 25 12.5 12.5 25 Water absorption [%] 0.01 0.01 0.01 0.01 0.01 metal layer Thickness [μm] 12 12 12 12 12 Rzjis[μm] 2.5 0.5 0.5 0.5 0.5 Conditions for thermocompression bonding Maximum temperature [℃] 330 330 330 330 330 Pressure [N/mm ² ] 4.0 4.0 4.0 4.0 4.0 Heating time [seconds] 210 210 210 210 210 Visual inspection ○ ○ ○ ○ ○ peel strength ○ × × × × High frequency transmission characteristics × ○ ○ ○ ○

As shown in Table 1, in Examples 1 to 6, good evaluation results were obtained regarding the peel strength between the thermosetting polyimide layer and the thermal fusion resin layer. Moreover, in Examples 1-5, since the metal layer was formed using the metal foil which has a high smoothness main surface, the favorable evaluation result was obtained also about the transmission characteristic of a high frequency.

On the other hand, as shown in Comparative Examples 1 to 4, when a thermosetting polyimide film having a water contact angle exceeding 20° was used, the peel strength between the thermosetting polyimide layer and the heat-sealing resin layer was not satisfactory. evaluation results.

11: Metal clad laminate 12: Insulation layer 13: Metal layer 21: Thermosetting polyimide layer 31: Thermal fusion resin layer 111: Laminate 113: Metal Foil 121: Thermosetting Polyimide Film 131: Thermoplastic resin film

FIG. 1 is a cross-sectional view showing a metal-clad laminate of the present embodiment. FIG. 2 is a schematic diagram illustrating a method of manufacturing a metal-clad laminate.

11: Metal clad laminate

12: Insulation layer

13: Metal layer

21: Thermosetting polyimide layer

31: Thermal fusion resin layer

Claims (11)

A metal-clad laminate, comprising an insulating layer and a metal layer laminated on one side or both sides of the insulating layer, The insulating layer includes a thermosetting polyimide layer and a thermal fusion resin layer disposed between the thermosetting polyimide layer and the metal layer, The said thermosetting polyimide layer consists of the thermosetting polyimide film whose water contact angle with the main surface of the said heat-sealing resin layer is 20 degrees or less. The metal-clad laminate of claim 1, wherein The above-mentioned thermosetting polyimide layer contains 3,3',4,4'-biphenyltetracarboxylic dianhydride and p-phenylenediamine as copolymerization components. The metal-clad laminate of claim 1 or claim 2, wherein The above-mentioned thermal fusion resin layer has a melting point of 280° C. or higher. The metal-clad laminate according to any one of Claims 1 to 3, wherein The said metal layer is comprised from the metal foil whose ten-point mean roughness (Rzjis) of the main surface joined with the said thermal fusion resin layer is 2.0 or less. The metal-clad laminate according to any one of claim 1 to claim 4, wherein The linear expansion coefficient of the said thermosetting polyimide layer exists 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 water absorption rate of the thermal fusion resin layer is lower than the water absorption rate of the thermosetting polyimide layer. The metal-clad laminate according to any one of Claims 1 to 6, wherein The peeling strength between the said thermosetting polyimide layer and the said heat fusion resin layer is 0.6 N/mm or more. The metal-clad laminate according to any one of claim 1 to claim 7, wherein The above-mentioned thermal fusion resin layer is formed of a fluorine-based resin. The metal-clad laminate according to any one of claim 1 to claim 8, wherein The above-mentioned thermosetting polyimide layer is composed of a thermosetting polyimide film disposed on the main surface on the side of the above-mentioned thermal fusion resin layer and subjected to discharge treatment, In the surface analysis of the above-mentioned thermosetting polyimide film using X-ray photoelectric spectroscopic analysis, the following formula was obtained from the integrated value A1 of 527 to 536 eV before the above-mentioned discharge treatment and the integrated value of 527 to 536 eV after the above-mentioned discharge treatment. (1) The calculated ratio R is 1.35 or more, R=A2/A1・・・(1). The metal-clad laminate according to any one of Claims 1 to 9, wherein The above-mentioned thermosetting polyimide layer is composed of a thermosetting polyimide film disposed on the main surface on the side of the above-mentioned thermal fusion resin layer and subjected to discharge treatment, In the surface analysis of the above-mentioned thermosetting polyimide film using X-ray photoelectric spectrometry, the sum of the respective cumulative values of 278 to 298 eV, 391 to 411 eV, 523 to 543 eV, and 94 to 114 eV was taken as 100%, and When the proportion occupied by the accumulated value of 523 to 543 eV in the total 100% is defined as the content of oxygen atoms, The amount of change C (%) of oxygen atoms calculated by the following formula (2) from the content B1 (%) of oxygen atoms before the discharge treatment and the content B2 (%) of oxygen atoms after the discharge treatment was 5% above, C(%)=B2-B1・・・(2). A method for manufacturing a metal-clad laminate, the metal-clad laminate comprising an insulating layer and a metal layer laminated on one side or both sides of the insulating layer, The insulating layer is provided with a thermosetting polyimide layer and a thermal fusion resin layer disposed between the thermosetting polyimide layer and the metal layer; The water contact angle of the surface is composed of a thermosetting polyimide film with a water contact angle of 20° or less. This production method includes a step of thermocompression bonding of a laminate in which the thermoplastic resin film as the thermal fusion resin layer is arranged between the thermosetting polyimide film and the metal foil as the metal layer.

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