JP7325899B2 - METHOD FOR MANUFACTURING METAL-CLAD LAMINATE, METHOD FOR MANUFACTURE AND REPAIR METHOD FOR COATED PRESSURE ROLL - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a metal-clad laminate used for flexible printed circuits (FPC) used in electronic products, and a method for manufacturing and repairing a covering pressure roll that can be used in the method.

An FPC is manufactured by etching a copper layer of a copper clad laminate (CCL) in which a resin layer and a copper layer are laminated to form circuit wiring. CCLs used in FPCs include single-sided copper-clad laminates (hereinafter referred to as single-sided CCL) in which copper foil is laminated only on one side of a resin layer, and double-sided copper-clad laminates (hereinafter referred to as double-sided copper-clad laminates in which copper foil is laminated on both sides of a resin layer). CCL) are known.

As a method for producing CCL, for example, a lamination method is known in which a copper foil and a resin film are thermocompressed using a metal press roll (see, for example, Patent Documents 1 and 2).

Regarding the lamination method, when laminating the liquid crystal polymer film and the metal foil, in order to improve the appearance of the laminate, a fluororubber or silicone rubber having a thickness of 0.02 to 5 mm is applied to the surface of a metal press roll. Alternatively, it has been proposed to use one provided with a polyimide resin coating layer (see, for example, Patent Document 3).

Japanese Patent Application Laid-Open No. 2001-129918 (Claims etc.) Japanese Patent Application Laid-Open No. 2009-66911 (Fig. 2, etc.) Japanese Patent No. 4398179 (Claims etc.)

2. Description of the Related Art In recent years, due to the high definition and multi-functionality of displays in mobile devices such as smartphones, finer wiring is progressing in FPCs used to connect components inside the housings of these devices. Along with this, in the CCL, which functions as a connection part by processing laminated copper foils to form wiring, the quality requirements for the adhesiveness between the copper foil and the resin layer are becoming stricter. However, when a metal foil and a polyimide film are laminated by a lamination method, the adhesiveness of the bonding surface and the filling of the thermocompression bonding surface tend to be insufficient, which causes peeling of the wiring when fine wiring is processed.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a metal-clad laminate in which the polyimide film evenly fills the irregularities on the surface of the metal foil and has high adhesiveness between the polyimide film and the metal foil.

As a result of extensive studies, the present inventors have found that when manufacturing a metal-clad laminate by the lamination method, the pressure surface of at least one of the pair of pressure rolls is covered with a film-like cushioning material. The present inventors have found that the above problems can be solved by performing thermocompression bonding in a state in which they are held together, and completed the present invention.

That is, in the method for producing a metal-clad laminate of the present invention, a polyimide film and a metal foil are superimposed and continuously passed through a pair of pressure rolls to bond the polyimide film and the metal foil together by thermocompression. It is a method of manufacturing a metal-clad laminate by In the method for manufacturing a metal-clad laminate of the present invention, the pressure surface of at least one pressure roll of the pair of pressure rolls is moved in synchronization with the pressure roll by a film-like cushioning material. Thermocompression bonding is performed in a covered state, and the film-like cushioning material includes a non-thermoplastic polyimide layer made of non-thermoplastic polyimide.

In the method for manufacturing a metal-clad laminate of the present invention, the film-like cushioning material may form a coating layer that covers the surface of the pressure roll on one side in the circumferential direction.

In the method for producing a metal-clad laminate of the present invention, the pressure roll on one side may be a coated pressure roll having the coating layer, and the pressure roll on the other side may be a metal roll.

In the method for manufacturing a metal-clad laminate of the present invention, the metal roll may be arranged on the metal foil side.

In the method for manufacturing a metal-clad laminate of the present invention, the film-like cushioning material may be formed in an annular shape, or may be rotatably formed by the pressure roll on one side and a plurality of guide rolls. good.

In the method for manufacturing a metal-clad laminate of the present invention, the film-like cushioning material may be formed in a long length and transported in a roll-to-roll manner.

In the method for producing a metal-clad laminate of the present invention, the film-like cushioning material may have a thickness of 1 to 200 μm.

In the method for producing a metal-clad laminate of the present invention, the polyimide film may contain a single or multiple layers of polyimide layers, at least one layer may be a non-thermoplastic polyimide, and at least the metal A thermoplastic polyimide layer may be provided on the surface of the side to be thermocompressed with the foil.

In the method for producing a metal-clad laminate of the present invention, the polyimide film may be a laminate structure including a substrate and a polyimide layer laminated on the substrate.

In the method for producing a metal-clad laminate of the present invention, the base material may be copper foil.

In the method for producing a coated pressure roll of the present invention, a polyimide film and a metal foil are superimposed and continuously passed between a pair of pressure rolls to bond the polyimide film and the metal foil by thermocompression. A method for manufacturing a coated pressure roll used when manufacturing a metal-clad laminate. In the method for manufacturing a coated pressure roll of the present invention, the coated pressure roll has a metal roll and a coating layer that covers the surface of the metal roll in the circumferential direction,
A step of applying a resin solution of polyimide or a polyimide precursor to the surface of the metal roll;
forming the coating layer by completing heat treatment of the resin solution on the metal roll;
characterized by comprising

In the method for manufacturing a coated pressure roll of the present invention, the resin solution may be applied to the surface of the metal roll while the roll is being rotated. In this case, the resin solution may be applied while relatively moving the applying means in the rotating shaft direction of the metal roll.

In the method for manufacturing a coated pressure roll of the present invention, the resin solution may be heat-treated by heating the metal roll using a heating mechanism for the metal roll.

In the method for repairing a covering pressure roll of the present invention, the polyimide film and the metal foil are thermally compressed by overlapping the polyimide film and the metal foil and passing them continuously between a pair of pressure rolls. A method for repairing a coated pressure roll used in manufacturing a metal-clad laminate. In the method for repairing a coated pressure roll of the present invention, the coated pressure roll has a metal roll and a coating layer circumferentially coating the surface of the metal roll,
A step of applying a resin solution of polyimide or a polyimide precursor to at least part of the surface of the coating layer;
completing heat treatment of the resin solution on the coated pressure roll;
characterized by comprising

According to the present invention, it is possible to manufacture a metal-clad laminate in which the polyimide film evenly fills the irregularities on the surface of the metal foil, and in which the polyimide film and the metal foil are firmly bonded. By using the metal-clad laminate thus produced as a material for circuit boards such as FPCs, it is possible to produce circuit boards having excellent adhesion between the miniaturized wiring and the insulating resin layer. Therefore, according to the present invention, the yield and reliability of circuit boards and electronic products using circuit boards can be improved.
Further, when a metal roll is used as the pressure roll, the pressure applied to the pressing surface tends to be non-uniform due to unevenness in the thickness of the polyimide film and variation in diameter of the metal roll in the width direction. At this time, a problem may arise in that the polyimide film does not sufficiently fill the irregularities on the surface of the metal foil at locations where the pressure is low. In the method of the present invention, by using a film-like cushioning material, this pressure unevenness is made uniform, and it is possible to manufacture a metal-clad laminate in which the unevenness of the surface of the metal foil is sufficiently filled with the polyimide film over the entire surface and firmly adhered. becomes.

BRIEF DESCRIPTION OF THE DRAWINGS It is drawing explaining the manufacturing method of the metal clad laminated board of the 1st Embodiment of this invention. FIG. 3 is a cross-sectional view showing the structure of a covering pressure roll; It is drawing explaining the manufacturing method of a covering pressure roll. It is drawing explaining the repair method of a covering pressure roll. It is drawing explaining the modification of the manufacturing method of the metal clad laminated board of 1st Embodiment. It is drawing explaining the manufacturing method of the metal clad laminated board of the 2nd Embodiment of this invention. It is drawing explaining the modification of the manufacturing method of the metal clad laminated board of 2nd Embodiment. It is drawing explaining the manufacturing method of the metal clad laminated board of the 3rd Embodiment of this invention. It is drawing explaining the modification of the manufacturing method of the metal clad laminated board of 3rd Embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings as appropriate. In the method for producing a metal-clad laminate of the present invention, a polyimide film and a metal foil are superimposed and continuously passed through a pair of pressure rolls, whereby the polyimide film and the metal foil are thermocompression bonded to form a metal-clad laminate. Manufacture laminates. At this time, thermocompression bonding is performed in a state in which the pressing surface of at least one pressure roll of the pair of pressure rolls is covered with a film-like cushioning material that can move in synchronism with the pressure roll. Here, the film-like cushioning material includes a non-thermoplastic polyimide layer made of non-thermoplastic polyimide. The term "non-thermoplastic polyimide" generally refers to polyimide that does not soften or exhibit adhesiveness when heated. A polyimide having a storage modulus of 1.0×10 ⁹ Pa or more at °C and a storage modulus of 3.0×10 ⁸ Pa or more at 300°C. Further, "thermoplastic polyimide" generally refers to a polyimide whose glass transition temperature (Tg) can be clearly confirmed. A polyimide having a storage modulus of 1.0×10 ⁹ Pa or more at 320° C. and less than 3.0×10 ⁸ Pa at 320° C.

Preferred aspects of the "film-like cushioning material" used in the method of the present invention will be described below with reference to first to third embodiments.

[First embodiment]
FIG. 1 is an explanatory diagram of a method for manufacturing a metal-clad laminate according to the first embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of the main part of the covering pressure roll used in this method. In the present embodiment, the polyimide film 10 and the metal foil 20 are superimposed and continuously passed between a pair of pressure rolls 30 and 40, whereby the polyimide film 10 and the metal foil 20 are thermocompression bonded and metal-clad. A laminate 100 is manufactured. The film-like cushioning material forms a coating layer 50 that covers the surface of the pressure roll 30 in the circumferential direction. That is, the pressure roll 30 on one side is a coated pressure roll having the coating layer 50 . Therefore, in the present embodiment, the pressure surface of at least one of the pressure rolls 30 and 40 out of the pair of pressure rolls 30 and 40 is a covering layer as a film-like cushioning material that can move in synchronization with the pressure roll 30. Thermal compression bonding is performed in the state covered with 50 . Here, the "pressing surface" of the pressure roll 30 is the surface of the rotating pressure roll 30, and the portion that presses the polyimide film 10 toward the metal foil 20 (the other pressure roll 40). means. The pressing surfaces are sequentially replaced by the rotation of the pressure roll 30 . Further, the portion of the coating layer 50 that is pressed against the polyimide film 10 is also sequentially replaced in synchronism with the rotation of the pressure roll 30 . Arrows in FIG. 1 indicate the direction of conveyance and the direction of rotation, and illustration of an unwinding roll, a winding roll, a guide roll, and the like is omitted. Also, the pair of pressure rolls 30 and 40 are each provided with a heating mechanism (not shown).

In FIG. 1, the other pressure roll 40 is a metal roll that does not have the coating layer 50, but both of the pressure rolls 30 and 40 may be coated pressure rolls that have the coating layer 50. FIG. Using coated pressure rolls as both of the pressure rolls 30 and 40 is effective in reducing variations in pressure during thermocompression bonding in the width direction of the rolls.
On the other hand, setting one of the pressure rolls 30 and 40 as a coated pressure roll and the other roll as a metal roll without the coating layer 50 is effective for efficiently conducting heat to the pressure bonding portion. In this case, as shown in FIG. 1, the pressure roll 40 that presses from the metal foil 20 side is preferably a metal roll that does not have the coating layer 50 . By arranging the metal roll on the metal foil 20 side, the heat can be more efficiently transferred to the crimping portion. That is, by bringing the metal pressure roll 40 and the metal foil 20 into direct contact, the pressure roll 40 heated by a heating mechanism (not shown) and the polyimide film 10 through the metal foil 20 with high thermal conductivity. Since heat can be quickly transferred to the pressure-bonded portion, the efficiency of thermocompression bonding is increased, and the adhesion between the polyimide film 10 and the metal foil 20 is improved.

<Coated pressure roll>
As shown in FIG. 2, the pressure roll 30 includes a core metal roll 31, an adhesive layer 33 surrounding the metal roll 31, and the metal roll 31 covered with the adhesive layer 33. A polyimide coating layer 35 is included. A coating layer 50 is composed of the adhesive layer 33 and the polyimide coating layer 35 . Note that the adhesive layer 33 may not be provided.

The adhesive layer 33 is preferably made of a polyimide adhesive. The adhesive layer 33 ensures adhesion between the metal roll 31 and the polyimide coating layer 35 . The polyimide-based adhesive refers to an adhesive having an imide bond, and includes, for example, siloxane polyimide, polyetherimide, and the like.

On the other hand, the polyimide coating layer 35 is preferably made of non-thermoplastic polyimide. By forming the polyimide coating layer 35 that is in direct contact with the polyimide film 10 from a non-thermoplastic polyimide, the polyimide coating layer 35 is partially heat-sealed to the polyimide film 10, causing appearance abnormalities such as wrinkles and stains. can be prevented.
The polyimide forming the polyimide coating layer 35 is preferably a heat-resistant polyimide having a glass transition temperature (Tg) of 300° C. or higher, for example. By using polyimide with a Tg of 300° C. or more, it is possible to avoid deformation and damage due to heating during thermocompression bonding, and increase the durability of the coating layer 50 .
From the same point of view, the Tg of the polyimide forming the polyimide coating layer 35 is preferably higher than the Tg of the thermoplastic polyimide (described later) forming part of the polyimide film 10 by, for example, 10° C. or more.
Moreover, the polyimide coating layer 35 preferably has a thermal conductivity of less than 0.2 W/m·K from the viewpoint of mitigating the thermal shock to the polyimide film 10 during thermocompression bonding.

In addition, in order to suppress dimensional changes due to temperature changes during thermocompression bonding and to ensure followability to the polyimide film 10 that is conveyed, the thermal expansion coefficient E of the polyimide coating layer 35 constituting the coating layer 50 is It is preferable that the coefficient of thermal expansion E1 of the film 10 as a whole satisfies, for example, 0.5×E≦E1≦1.5×E.

The thickness of the coating layer 50 (meaning the total thickness of the adhesive layer 33 and the polyimide coating layer 35 in the present embodiment) is not particularly limited, but is preferably in the range of 1 to 200 μm, It is more preferably within the range of 10 to 100 μm. The upper limit of the thickness is preferably 200 μm or less for efficient heat transfer. Further, as will be described later, when the coating layer 50 is formed by applying a polyimide or polyimide precursor resin solution to the surface of the metal roll 31 and then performing heat treatment, the coating layer 50 can be easily formed. 100 μm or less is more preferable. Furthermore, in order to prevent temperature variations in the width direction of the metal roll 31, the thickness of the coating layer 50 is preferably 25 μm or less. The lower limit of the thickness is preferably 1 μm or more, more preferably 5 μm or more, so as to withstand repeated use.

The coating layer 50 as a film-like cushioning material has the effect of alleviating pressure imbalance during thermocompression bonding and evenly distributing the pressure, and has the effect of uniformly bonding the polyimide film 10 and the metal foil 20 . Therefore, the polyimide film 10 evenly fills the irregularities on the surface of the metal foil 20, and the metal-clad laminate 100 in which the polyimide film 10 and the metal foil 20 are strongly bonded can be manufactured.

A film containing at least a non-thermoplastic polyimide can be preferably used for the coating layer 50, but a film consisting of only the non-thermoplastic polyimide may be used, or may contain other components as necessary. Other components specifically include resins other than non-thermoplastic polyimide, various additives for improving various properties of the coating layer 50, and the like. In addition, non-thermoplastic polyimides may also be used in combination. Moreover, a filler or the like may also be contained.

<Manufacturing method of coated pressure roll>
The pressure roll 30 having the metal roll 31 and the coating layer 50 that covers the surface of the metal roll 31 in the circumferential direction, for example, the following steps a and b;
a) a step of applying a resin solution of polyimide or a polyimide precursor to the surface of the metal roll 31;
b) forming the coating layer 50 by completing the heat treatment of the resin solution on the metal roll 31;
It can be manufactured by a method including

In step a, it is preferable to apply the resin solution to the surface of the metal roll 31 while rotating it. As a method of applying the resin solution onto the metal roll 31, for example, a coating means such as a coater or a spray may be used. good. When the resin solution is applied to the surface of the metal roll 31 using a coating means such as a coater or a sprayer, the resin solution is applied while the coating means is relatively moved in the rotational axis direction of the metal roll 31. is more preferred. For example, as shown in FIG. 3, the ejection port of the coating means 61 is brought close to or in contact with the surface of the metal roll 31, and while the metal roll 31 is rotated, the ejection port is moved in the direction of the rotation axis of the metal roll 31. It is preferable to continuously supply the resin solution 63 to the surface of the metal roll 31 from the discharge port while moving it relatively. Here, "relatively moving the outlet in the direction of the rotation axis of the metal roll 31" means moving from one end of the rotating metal roll 31 to the other end. Therefore, the resin solution 63 is spirally applied to the surface of the metal roll 31 . After applying the resin solution 63 to the surface of the metal roll 31 , the metal roll 31 may be rotated before starting the heat treatment for the purpose of uniforming the thickness of the resin solution 63 .

In step b, the heat treatment is completed by heating on the metal roll 31 to form the coating layer 50 . Heating may be performed by placing the metal roll 31 in an oven to heat the entire surface, or by applying hot air to the surface of the metal roll 31 from a heater. Alternatively, the inside of the metal roll 31 may be heated using a heating mechanism (not shown) of the metal roll 31 itself.

The heat treatment conditions vary depending on the chemical structure, thickness and area of the polyimide constituting the coating layer 50, the type of solvent of the resin solution 63, etc., but the maximum temperature is preferably in the range of 300° C. or higher and 500° C. or lower. Moreover, rapid heating may generate outgassing at the time of temperature rise and generate air bubbles. Therefore, it is preferable to raise the temperature to the maximum temperature over a period of 30 minutes or longer, for example.

When the coating layer 50 is composed of a plurality of polyimide layers, the above steps a and b may be repeated, or step a may be repeated a predetermined number of times and then step b may be collectively performed.

<Method for repairing coated pressure roll>
When forming the coating layer 50 on the surface of the metal roll 31, the coating layer 50 may have defects such as air bubbles, surface roughness, and adhesion of foreign substances. Also, similar defects may occur in the use of the pressure roll 30 having the coating layer 50 , that is, in the manufacture of the metal-clad laminate 100 . If a defect occurs in the coating layer 50 of the pressure roll 30, the defect can be repaired. The repair of the pressure roll 30 having the coating layer 50 is performed, for example, by the following steps c and d;
c) applying a polyimide or polyimide precursor resin solution to at least a portion of the surface of the coating layer 50 (e.g., the defective portion and its surroundings);
d) completing the heat treatment of the resin solution on the pressure roll 30 with the coating layer 50;
can include

In step c, for example, as shown in FIG. 4, the ejection port of coating means 61 such as a syringe is brought close to or in contact with the surface of the metal roll 31, and the resin solution 63 is locally applied to the surface of the metal roll 31 from the ejection port. apply evenly.

The heat treatment in step d can be carried out in the same manner as in step b in the manufacturing method of the coated pressure roll.

Prior to step c, the step c may be performed after removing the defects and the coating layer 50 therearound from the surface of the metal roll 31 . Further, after the heat treatment in step d is completed, a treatment for smoothing the surface of the coating layer 50, for example, polishing with an abrasive may be performed.

<Polyimide film>
The polyimide film 10 to be thermocompression-bonded to the metal foil 20 includes a single-layer or multiple-layer polyimide layer, and may include any layer other than the polyimide layer. In this case, it is preferable that at least one layer is a non-thermoplastic polyimide layer, and at least the surface of the metal foil 20 that is thermocompression bonded is a thermoplastic polyimide layer. In this case, in order to ensure adhesion with the metal foil 20, the glass transition temperature (Tg) of the thermoplastic polyimide is preferably within the range of 200 to 350°C, more preferably within the range of 280 to 320°C. stomach.

The thickness of the polyimide film 10 is, for example, preferably in the range of 1 to 150 μm, more preferably in the range of 2 to 100 μm, from the viewpoint of realizing a thinner circuit board such as an FPC obtained by processing the metal-clad laminate 100. more preferred. If the thickness of the polyimide film 10 is less than 1 μm, functions such as electrical insulation may be impaired. When the thickness of the polyimide film 10 exceeds 150 μm, it becomes difficult to reduce the thickness of circuit boards such as FPCs.

It is preferable that the thermal expansion coefficient of the entire polyimide film 10 approximates that of the metal foil 20 as closely as possible. By bringing the coefficient of thermal expansion of the polyimide film 10 close to that of the metal foil 20, it is possible to suppress the occurrence of warping during the processing of the FPC. From this point of view, in the metal-clad laminate 100, the coefficient of thermal expansion E1 of the entire polyimide film 10 and the coefficient of thermal expansion E2 of the metal foil 20 are, for example, 0.7×E1≦E2≦1.1×E1. It is preferable to have a relationship of

Moreover, the polyimide film 10 may be in the form of a laminated structure containing arbitrary layers other than the polyimide layer. Optional layers include, for example, a substrate and a release film. A preferred embodiment of the polyimide film 10 is a polyimide film 10A having a laminated structure including a substrate 71 and a polyimide layer 73 laminated on the substrate 71, as shown in FIG. Here, as the base material 71, for example, a metal foil such as a copper foil can be used. When the base material 71 is copper foil, the polyimide film 10A is single-sided CCL. The use of a single-sided CCL as the polyimide film 10A is particularly advantageous because it enables the manufacture of a double-sided CCL (double-sided copper-clad laminate) used for a double-sided circuit board capable of high-density wiring. Further, when a single-sided CCL is used as the polyimide film 10A, it is preferable that the pressure roll 30 having the coating layer 50 is placed in pressure contact with the copper foil layer side of the single-sided CCL. This is because the coating layer 50 of the pressure roll 30 intervenes, so that the copper foil as the base material 71 can be prevented from being subjected to excessive heat history. In addition, by arranging the pressure roll 30 having the coating layer 50 on the copper foil layer side of the single-sided CCL so as to be in pressure contact, the pressure roll 30 is prevented from coming into close contact with the copper foil as the base material 71, Transportability can be maintained, and micro-sized defects in the copper foil can be prevented.

The single-sided CCL as the polyimide film 10A is manufactured by a casting method in which a resin solution of polyimide or a polyimide precursor is applied onto the substrate 71, dried, and then heat-treated to form the polyimide layer 73. A single-sided CCL is preferred. Also, the polyimide layer 73 may be formed of only a single layer, but it is preferable that it be formed of multiple layers in consideration of the adhesiveness and dimensional stability between the polyimide layer 73 and the copper foil. When the polyimide layer 73 is formed as a plurality of layers, it can be formed by sequentially applying other polyimides or polyimide precursor resin solutions having different components on a polyimide or polyimide precursor resin solution. When the polyimide layer 73 is composed of multiple layers, the same resin solution may be used two or more times. In addition, the single-sided CCL manufactured by the casting method is an advantageous embodiment with excellent dimensional stability. can be kept low. When using a single-sided CCL as the polyimide film 10A, the metal-clad laminate 100A obtained is a double-sided CCL (double-sided copper-clad laminate).

When the polyimide layer 73 in the single-sided CCL has a laminated structure of a non-thermoplastic polyimide layer and a thermoplastic polyimide layer, the thickness ratio of the non-thermoplastic polyimide layer and the thermoplastic polyimide layer (non-thermoplastic polyimide layer/ thermoplastic polyimide layer) is preferably in the range of 1.5 to 10.0. If the value of this ratio is less than 1.5, the non-thermoplastic polyimide layer becomes thin with respect to the entire polyimide layer 73, so the dimensional change rate when etching the copper foil tends to increase. Since the plastic polyimide layer becomes thin, the adhesion reliability between the polyimide layer 73 and the copper foil tends to be lowered.

<Metal foil>
Examples of metals for the metal foil 20 include copper, aluminum, stainless steel, iron, silver, palladium, nickel, chromium, molybdenum, tungsten, zirconium, gold, cobalt, titanium, tantalum, zinc, lead, tin, silicon, bismuth, and indium. Alternatively, metals selected from these alloys can be used. A metal foil of copper or a copper alloy is particularly preferable in terms of conductivity. In order to continuously produce the metal-clad laminates 100 and 100A, a long metal foil 20 having a predetermined thickness wound into a roll is used.

The surface roughness of the surface of the metal foil 20 that is in direct contact with the polyimide film 10 is preferably, for example, 0.1 to 7 μm in terms of Rz. This is because within this range, the adhesive strength with the polyimide film 10 is sufficiently good. Furthermore, it is more preferable if Rz is 0.3 to 3.0 μm. Here, Rz indicates the ten-point average roughness specified in JIS B 0601 (1994).

<Thermal compression bonding conditions>
A heating method for the pressure rolls 30 and 40 is not particularly limited as long as it can be heated at a predetermined temperature. The pressurization method is not particularly limited as long as it can apply a predetermined pressure, and examples thereof include a hydraulic method, an air pressure method, and a gap pressure method.

The pressure during thermocompression bonding between the polyimide film 10 and the metal foil 20 by the pressure rolls 30 and 40 is not particularly limited, but is preferably in the range of 0.1 to 50 MPa, for example.

The temperature during thermocompression bonding is preferably 280.degree. C. or higher, more preferably within the range of 300.degree.

[Second embodiment]
FIG. 6 is an explanatory diagram of a method for manufacturing a metal-clad laminate according to the second embodiment of the present invention. In this embodiment, the film-like cushioning material is formed in an annular shape. That is, in the present embodiment, the annular polyimide film 50A is arranged on the outer periphery of at least one pressure roll 40A of the pair of metal pressure rolls 40A and 40B, and this is used as a film cushioning material. Here, "annular" includes a cylindrical shape. In FIG. 6, the film-like cushioning material is not arranged on the side of the other pressure roll 40B, but the thermocompression bonding may be performed in a state in which both the pressure rolls 40A and 40B are covered with the film-like cushioning material. .

The inner diameter of the annular polyimide film 50A is larger than the outer diameter of the pressure roll 40A, and is rotatable by the pressure roll 40A on one side and the guide rolls 80A and 80B. By rotating the annular polyimide film 50A in the same direction as the rotation direction of the pressure roll 40A, the pressing surface of the pressure roll 40A is covered with the annular polyimide film 50A movable in synchronization with the pressure roll 40A. Thermal compression bonding can be performed at The number of guide rolls is not limited to two, and one or three or more may be arranged.

As described above, since the inner diameter of the annular polyimide film 50A is larger than the outer diameter of the pressure roll 40A, the annular polyimide film 50A is not fixed to the pressure roll 40A. Polyimide has a hygroscopic property, and there is concern that moisture contained in the annular polyimide film 50A may rapidly volatilize during thermocompression bonding, causing the appearance of the metal-clad laminate 100 to be poor. When the inner diameter of the annular polyimide film 50A is sufficiently larger than the outer diameter of the pressure roll 40A, before the annular polyimide film 50A reaches the thermocompression bonding surface, the pressure roll 40A is partially covered and preheated. Therefore, the water contained in the annular polyimide film 50A can be reduced. It is preferable that the time for which the annular polyimide film 50A is in contact with the pressure roll 40A is 1 second or longer.

Although the thickness of the cyclic polyimide film 50A is not particularly limited, it is preferably in the range of 1 to 200 μm, more preferably in the range of 10 to 100 μm . The upper limit of the thickness is preferably 200 μm or less in order to efficiently conduct heat, and is preferably 25 μm or less in order to prevent temperature variations in the width direction of the pressure roll 40A. The lower limit of the thickness is preferably 1 μm or more, more preferably 5 μm or more, so as to withstand repeated use.

For the annular polyimide film 50A, for example, a resin solution of polyimide or a polyimide precursor is applied to the surface of a cylindrical or cylindrical release material, the resin solution is completely heat-treated on the release material, and then peeled off from the release material. It can be manufactured by The method of applying the resin solution to the release material and the heat treatment conditions can be carried out according to the steps a and b in the method of manufacturing the coated pressure roll.

The annular polyimide film 50A may include a single or multiple polyimide layers. In this case, it is preferable that at least one layer is a non-thermoplastic polyimide layer, and at least the surface (inner peripheral surface) in contact with the pressure roll 40A is a thermoplastic polyimide layer. In other words, the annular polyimide film 50A may be easily adhered to the surface of the metal pressure roll 40A by using a highly adhesive thermoplastic polyimide layer.

On the other hand, in the annular polyimide film 50A, the surface (peripheral surface) of the side that is in direct contact with the polyimide film 10 is preferably made of non-thermoplastic polyimide. By forming the surface in direct contact with the polyimide film 10 with a non-thermoplastic polyimide layer, it is possible to prevent appearance abnormalities such as wrinkles and stains due to partial heat-sealing of the annular polyimide film 50A to the polyimide film 10. can. The polyimide constituting the non-thermoplastic polyimide layer in the cyclic polyimide film 50A is preferably a heat-resistant polyimide having a glass transition temperature (Tg) of 300° C. or higher, for example. By using a polyimide having a Tg of 300° C. or more, it is possible to avoid deformation and damage due to heat during thermocompression bonding, and increase the durability of the annular polyimide film 50A.
Also, from the same point of view, the Tg of the non-thermoplastic polyimide layer in the annular polyimide film 50A is preferably higher than the Tg of the thermoplastic polyimide (described later) forming part of the polyimide film 10 by, for example, 10° C. or more.

In addition, in order to suppress dimensional changes due to temperature changes during thermocompression bonding and to ensure precise followability to the polyimide film 10 being conveyed, the thermal expansion coefficient E3 of the entire annular polyimide film 50A is It is preferable to satisfy the relationship of, for example, 0.5×E3≦E1≦1.5×E3 with respect to the thermal expansion coefficient E1 of the whole.

A ring-shaped metal-clad laminate such as a ring-shaped CCL may also be used as the ring-shaped polyimide film 50A. By using a ring-shaped metal-clad laminate as the ring-shaped polyimide film 50A, handleability and durability can be improved. From the viewpoint of durability, the annular metal-clad laminate used as the annular polyimide film 50A is preferably an annular metal-clad laminate produced by a casting method.

The annular polyimide film 50A as a film-like cushioning material has the effect of relieving and evenly distributing the pressure during thermocompression bonding, and has the effect of uniformly bonding the polyimide film 10 and the metal foil 20 together.

Other configurations and effects in this embodiment are the same as those in the first embodiment. Also in this embodiment, as a modification, metal-clad laminate 100A can be manufactured by using polyimide film 10A having a laminated structure instead of polyimide film 10, as shown in FIG.

It is preferable that the annular polyimide film 50A is preheated to reduce the water content before the thermocompression bonding. For example, the polyimide that constitutes the annular polyimide film 50A has a hygroscopic property, and the accompanying moisture volatilizes at the time of thermocompression bonding. There is When the annular polyimide film 50A is used for thermocompression bonding, the annular polyimide film 50A is heated by increasing the angle of insertion, for example, to allow time for contact with the pressure roll 40A before reaching the thermocompression bonding surface. It is possible to preheat the annular polyimide film 50A by contacting it so as to cover a part of the pressure roll 40A. At this time, the contact time of the annular polyimide film 50A with the pressure roll 40A is preferably 1 second or longer.

[Third Embodiment]
FIG. 8 is an explanatory diagram of a method for manufacturing a metal-clad laminate according to the third embodiment of the present invention. In this embodiment, the film-like cushioning material is formed in a long length and is transported in a roll-to-roll manner. That is, in the present embodiment, the long polyimide film 50B is arranged between the pressure roll 40A on at least one side of the pair of metal pressure rolls 40A and 40B and the polyimide film 10. cushioning material. In FIG. 8, the film-like cushioning material is not arranged on the side of the other pressure roll 40B, but the thermocompression bonding may be performed in a state in which both the pressure rolls 40A and 40B are covered with the film-like cushioning material. .

The long polyimide film 50B is formed so as to be transportable by the pressure roll 40A, the unwind roll 90A, and the winding roll 90B. The long polyimide film 50B is transported in the same direction as the rotation direction of the pressure roll 40A so that the pressing surface of the pressure roll 40A can move in synchronization with the pressure roll 40A. Thermocompression bonding can be performed in a state covered by. In addition, one or more guide rolls may optionally be provided in order to adjust the angle at the time of contact with the pressure roll 40A and the angle at the time of separation.

As described above, the long polyimide film 50B is not fixed to the pressure roll 40A. As in the case of the annular polyimide film 50A in the second embodiment, the long polyimide film 50B, which is conveyed at the same speed as the pressure roll 40A, reaches one of the pressure rolls 40A before reaching the thermocompression bonding surface. Since it is possible to preheat by contacting the part so as to cover it, the moisture contained in the long polyimide film 50B can be reduced. It is preferable that the long polyimide film 50B is in contact with the pressure roll 40A for 1 second or longer.

Although the thickness of the long polyimide film 50B is not particularly limited, it is preferably in the range of 1 to 200 μm, more preferably in the range of 10 to 100 μm . The upper limit of the thickness is preferably 200 μm or less in order to efficiently conduct heat, and is preferably 25 μm or less in order to prevent temperature variations in the width direction of the pressure roll 40A. The lower limit of the thickness is preferably 1 μm or more, more preferably 5 μm or more, so as to withstand repeated use.

The long polyimide film 50B may include a single or multiple polyimide layers. In this case, it is preferable that at least one layer is a non-thermoplastic polyimide layer, and at least the surface that contacts the pressure roll 40A is a thermoplastic polyimide layer. In other words, the elongated polyimide film 50B may be easily adhered to the surface of the metal pressure roll 40A by using a highly adhesive thermoplastic polyimide layer.

On the other hand, it is preferable that the surface of the long polyimide film 50B that is in direct contact with the polyimide film 10 is made of non-thermoplastic polyimide. By forming the surface in direct contact with the polyimide film 10 with a non-thermoplastic polyimide layer, it is possible to prevent appearance abnormalities such as wrinkles and stains due to partial fusion of the long polyimide film 50B to the polyimide film 10. can. The polyimide constituting the non-thermoplastic polyimide layer in the elongated polyimide film 50B is preferably a heat-resistant polyimide with a glass transition temperature (Tg) of 300° C. or higher, for example. By using polyimide with a Tg of 300° C. or more, deformation and damage due to heat during thermocompression bonding can be avoided, and the durability of the long polyimide film 50B can be increased.
Also, from the same point of view, the Tg of the non-thermoplastic polyimide layer in the long polyimide film 50B is preferably higher than the Tg of the thermoplastic polyimide (described later) that constitutes a part of the polyimide film 10 by, for example, 10° C. or more. .

In addition, in order to suppress dimensional changes due to temperature changes during thermocompression bonding and to ensure precise followability to the polyimide film 10 being conveyed, the thermal expansion coefficient E4 of the entire long polyimide film 50B is set to polyimide to be described later. It is preferable that the coefficient of thermal expansion E1 of the film 10 as a whole satisfies, for example, 0.5×E4≦E1≦1.3×E4.

As the long polyimide film 50B, commercially available polyimide films such as Kapton V (trade name) manufactured by Toray DuPont and Upilex S (trade name) manufactured by Ube Industries, Ltd. may be used.

Also, a long metal-clad laminate such as CCL may be used as the long polyimide film 50B. By using a metal-clad laminate as the elongated polyimide film 50B, it is possible to improve handling properties and durability. The metal-clad laminate used as the long polyimide film 50B is preferably a metal-clad laminate manufactured by a casting method from the viewpoint of durability and thickness uniformity.

The long polyimide film 50B as a film-like cushioning material has the effect of relieving and evenly distributing the pressure during thermocompression bonding, and has the effect of uniformly bonding the polyimide film 10 and the metal foil 20 together.

Other configurations and effects in this embodiment are the same as those in the first and second embodiments. Also in this embodiment, as a modification, metal-clad laminate 100A can be manufactured by using polyimide film 10A having a laminated structure instead of polyimide film 10, as shown in FIG.

It is preferable that the elongated polyimide film 50B is preheated to reduce the water content before the thermocompression bonding. For example, the polyimide that constitutes the long polyimide film 50B has a hygroscopic property, and the moisture contained accompanying this evaporates during thermocompression bonding. There are concerns that arise. When the long polyimide film 50B is used for thermocompression bonding, the long polyimide film 50B is allowed to contact with the pressure roll 40A before reaching the thermocompression bonding surface by, for example, increasing the insertion angle. The long polyimide film 50B can be heated in advance by contacting the film 50B so as to partially cover the pressure roll 40A. At this time, the length of time that the long polyimide film 50B is in contact with the pressure roll 40A is preferably 1 second or longer.

As described above, in the metal-clad laminates 100 and 100A obtained in the first to third embodiments, the polyimide films 10 and 10A evenly fill the irregularities on the surface of the metal foil 20, and the polyimide films 10 and 10A and the metal foil 20 are strongly bonded. The adhesive strength (peel strength) between the polyimide films 10 and 10A and the metal foil 20 can be controlled by the type and ratio of raw material monomers of polyimide constituting the polyimide films 10 and 10A, heat treatment conditions, and the like.

[Polyimide]
Next, the polyimide constituting part or all of the polyimide films 10, 10A, the coating layer 50, the annular polyimide film 50A, or the elongated polyimide film 50B in the first to third embodiments will be described. Polyimide is produced by imidizing polyamic acid, which is a precursor, and is produced by reacting a specific acid anhydride with a diamine compound. A specific example is understood. In the present invention, the term "polyimide" means a resin composed of a polymer having an imide group in its molecular structure, such as polyamideimide, polyetherimide, polyesterimide, polysiloxaneimide, and polybenzimidazoleimide, in addition to polyimide.

Aromatic diamine compounds, aliphatic diamine compounds, and the like can be used as the diamine compound as a raw material of the polyimide. For example, an aromatic diamine compound represented by NH ₂ —Ar1—NH ₂ is preferable. Here, Ar1 is selected from the groups represented by the following formulas, and the substitution position of the amino group is arbitrary, but the p and p' positions are preferred. Ar1 may have a substituent, but it preferably does not have one, or if it has one, the substituent is preferably a lower alkyl or lower alkoxy group having 1 to 6 carbon atoms. These aromatic diamine compounds may be used alone or in combination of two or more.

As the acid anhydride to be reacted with the diamine compound, an aromatic tetracarboxylic acid anhydride is preferable from the viewpoint of ease of synthesizing polyamic acid. The aromatic tetracarboxylic acid anhydride is not particularly limited, but suitable examples thereof include compounds represented by O(CO) ₂ Ar2(CO) ₂ O. Here, Ar2 is preferably a tetravalent aromatic group represented by the following formula, and although the substitution position of the acid anhydride group [(CO) ₂ O] is arbitrary, symmetrical positions are preferred. Ar2 may have a substituent, but it preferably has no substituent, or if it does, the substituent is preferably a lower alkyl group having 1 to 6 carbon atoms.

The polyimide films 10, 10A, the coating layer 50, the annular polyimide film 50A, and the elongated polyimide film 50B can have a multilayer structure including a thermoplastic polyimide layer and a non-thermoplastic polyimide layer. Preferable examples of the acid anhydride and the diamine compound used for each of are described below.

Thermoplastic polyimide:
When the polyimide is a thermoplastic polyimide, it is not particularly limited, but examples of the diamino component of the raw material include 3,4'-diaminodiphenyl ether, 1,3-bis(4-aminophenoxy)benzene, 1,4- It is preferable to use a diamine compound containing 50 mol % or more of one or more selected from bis(4-aminophenoxy)benzene and 2,2-bis[4-(4-aminophenoxy)phenyl]propane. In addition, although not particularly limited, as the acid anhydride component of the raw material, for example, pyromellitic dianhydride, 3,3′,4,4′-biphenyltetracarboxylic dianhydride, benzophenonetetracarboxylic dianhydride, Using an acid anhydride containing 50 mol % or more of one or more selected from anhydride, 3,3′,4,4′-diphenylsulfonetetracarboxylic dianhydride, and 4,4′-oxydiphthalic anhydride is preferred. By using a predetermined amount of these diamine compounds and acid anhydrides, the adhesiveness of the thermoplastic polyimide is sufficiently exhibited, and the thermocompression bondability is enhanced.

Non-Thermoplastic Polyimide:
When the polyimide is a non-thermoplastic polyimide, it is not particularly limited, but examples of the diamino component of the raw material include 1,3-phenylenediamine, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2, It is preferable to use a diamine compound containing 60 mol % or more of one or more selected from 2'-bis(trifluoromethyl)benzidine and 3,4'-diaminodiphenyl ether. In addition, although not particularly limited, as the acid anhydride component of the raw material, for example, one or more selected from pyromellitic dianhydride and 3,3′,4,4′-biphenyltetracarboxylic dianhydride It is preferable to use an acid anhydride containing 60 mol % or more of. By using a predetermined amount of these diamine compounds and acid anhydrides, the properties of non-thermoplastic polyimide such as heat resistance and dimensional stability are exhibited.

In the thermoplastic polyimide and non-thermoplastic polyimide, the thermal expansion coefficient, storage modulus, glass transition temperature, etc. can be controlled by selecting the types of diamine compounds and acid anhydrides and their respective molar ratios.

When the thermoplastic polyimide and the non-thermoplastic polyimide have a plurality of polyimide structural units, they may be present as blocks or randomly, but are preferably present randomly.

For polyimide, for example, in a solvent, the above diamine compound and acid anhydride are mixed in a substantially equimolar ratio and reacted at a reaction temperature of 0 to 200 ° C., preferably 0 to 100 ° C. to produce polyamic acid. can be obtained by obtaining a resin solution of and further imidizing it. Examples of solvents include N-methylpyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc), dimethylsulfoxide (DMSO), dimethyl sulfate, sulfolane, butyrolactone, cresol, phenol, halogenated phenol, Cyclohexanone, dioxane, tetrahydrofuran, diglyme, triglyme and the like.

Synthesis of polyamic acid is usually carried out in a reaction vessel or the like. For example, a polyimide layer can be obtained by coating a polyamic acid resin solution on an arbitrary substrate, drying to form a polyamic acid layer, and imidizing the polyamic acid layer by subsequent heat treatment. The application may be repeated on top of an already formed polyamic acid layer or on a polyimide layer. Alternatively, the polyimide layer may be formed by coating the surface of any base material in the form of a solution obtained by dissolving preliminarily imidized polyimide in a solvent and drying the solution. When the polyimide films 10 and 10A, the coating layer 50, the cyclic polyimide film 50A, and the long polyimide film 50B have a multilayer structure, a plurality of polyamic acid resin solutions are sequentially applied on an arbitrary substrate and dried. Although the method of imidizing them all at once later is preferable, it is not limited to this method. That is, a plurality of polyamic acid resin solutions are applied to an arbitrary base material at once using a multi-layer die or the like, dried, and then imidized by heat treatment at once to form a plurality of polyimide layers. may Alternatively, the polyimide layers may be formed one by one by successively performing the processes from application and drying of a plurality of polyamic acid resin solutions to imidization. Each of these treatments can be combined arbitrarily to form a plurality of polyimide layers.

The method of applying the polyimide solution or polyamic acid resin solution onto any substrate is not particularly limited, and can be applied by a coating means represented by a coater such as a comma, die, knife, lip, or the like. It is possible. When forming multiple polyimide layers, it is preferable to repeat the operation of applying a polyimide solution (or polyamic acid resin solution) to a base material and drying it.

As a method for drying and heat imidization treatment, any method such as a batch treatment method or a continuous treatment method can be selected. In the batch processing method, after coating a polyamic acid resin solution on a long metal foil, the laminate is wound into a roll without being imidized, and dried in a hot air drying oven that can be set to a predetermined temperature. is left at rest for a certain period of time, and finally imidization is completed by heat-treating at a high temperature of 200° C. or higher. In the continuous processing method, after applying a resin solution of polyamic acid to a long metal foil, it is continuously moved in a drying furnace to secure a predetermined heat treatment time, and finally heated to a high temperature of 200 ° C or higher. It is a method of performing heat treatment by Any of these methods may be selected from the viewpoint of productivity, yield, etc., but the heat treatment at a high temperature of 200 ° C. or higher is performed in a reduced pressure environment, in a reducing gas atmosphere, or in a reducing gas atmosphere and a reduced pressure environment. It is preferable to perform The solvent of the polyamic acid resin is removed and imidized by heating in the drying and imidization treatment steps. At this time, if the heat treatment is performed rapidly at a high temperature, a skin layer is formed on the resin surface and the solvent is difficult to evaporate. It is preferable to perform the heat treatment while gradually increasing the temperature from a low temperature to a high temperature. Further, in the thermal imidization step, it is preferable to finally heat-treat at a temperature of 300 to 400°C.

EXAMPLES Examples are given below to more specifically describe the features of the present invention. However, the scope of the present invention is not limited to the examples. In the following examples, unless otherwise specified, various measurements and evaluations are as follows.

[Coefficient of thermal expansion (CTE)]
A polyimide film having a size of 3 mm × 20 mm is heated from 30 ° C. to 265 ° C. at a constant heating rate while applying a load of 5.0 g using a thermomechanical analyzer (manufactured by Bruker, trade name: 4000SA). Further, after holding at that temperature for 10 minutes, it was cooled at a rate of 5°C/min, and the average thermal expansion coefficient (linear thermal expansion coefficient) from 240°C to 100°C was determined.

[Glass transition temperature (Tg)]
For the glass transition temperature, a polyimide film having a size of 5 mm × 20 mm was measured using a dynamic viscoelasticity measuring device (DMA: manufactured by UBM, trade name: E4000F), and the temperature was increased from 30 ° C. to 400 ° C. Measurement was performed at 4° C./min and a frequency of 11 Hz, and the temperature at which the change in elastic modulus (tan δ) was maximum was taken as the glass transition temperature.

[Measurement of viscosity]
The viscosity was measured at 25° C. using an E-type viscometer (manufactured by Brookfield, trade name: DV-II+Pro). The rotation speed was set so that the torque was 10% to 90%, and after 2 minutes from the start of measurement, the value was read when the viscosity stabilized.

[Peel strength]
The peel strength was measured using a Tensilon tester (manufactured by Toyo Seiki Seisakusho Co., Ltd., trade name: Strograph VE-1D), and the metal on the conductor layer side was processed into wiring with a width of 1 mm. It was fixed to the SUS plate with a tape, and the force when peeling the metal wiring from the resin layer was obtained at a speed of 50 mm/min in the direction of 180°.

[Filling state of thermocompression surface]
After etching the entire width of the copper foil of the copper-clad laminate after thermocompression bonding, the surface of the polyimide film was visually observed. did.

Abbreviations used in Examples and the like indicate the following compounds.
BAPP: 2,2-bis[4-(4-aminophenoxy)phenyl]propane m-TB: 2,2'-dimethyl-4,4'-diaminobiphenyl PMDA: pyromellitic dianhydride BPDA: 3,3 ',4,4'-Biphenyltetracarboxylic dianhydride DMAc: N,N-dimethylacetamide

<Synthesis of polyamic acid solution>
(Synthesis example 1)
87.5 kg of DMAc was placed in a reaction vessel equipped with a thermocouple and a stirrer and capable of introducing nitrogen, and 8.11 kg of BAPP was added to the reaction vessel and dissolved while stirring in the vessel. Then 4.10 kg of PMDA was charged. Thereafter, stirring was continued for 3 hours to carry out a polymerization reaction to obtain a resin solution 1 of polyamic acid a. Resin solution 1 (solid content: 12.5%) had a viscosity of 1,300 cps. In addition, the polyimide obtained by imidating polyamic acid a is thermoplastic, and the coefficient of thermal expansion (CTE) of a 25 μm-thick polyimide film formed from polyamic acid a is 55×10 ⁻⁶ /K, and glass The transition temperature was 320°C.

(Synthesis example 2)
212.5 kg of DMAc was put into a reaction vessel equipped with a thermocouple and a stirrer and capable of introducing nitrogen, and 17.9 kg of m-TB was added to the reaction vessel and dissolved while stirring in the vessel. . Then 4.94 kg BPDA and 14.7 kg PMDA were charged. Thereafter, stirring was continued for 3 hours to carry out a polymerization reaction to obtain a resin solution 2 of polyamic acid b. Resin solution 2 (solid content: 15%) had a viscosity of 26,500 cps. In addition, the polyimide obtained by imidating the polyamic acid b is non-thermoplastic, and the thermal expansion coefficient (CTE) of the 25 μm-thick polyimide film formed from the polyamic acid b was 22×10 ⁻⁶ /K. .

[Manufacture of polyimide-coated roll]
While rotating the metal roll equipped with a heater inside, the resin solution 2 prepared in Synthesis Example 2 was applied to the surface of the metal roll using a coater, and then the metal roll was heated with the heater to cool from room temperature. The temperature was raised to 360° C. over one hour to obtain a polyimide-coated roll having a polyimide coating layer with a predetermined thickness on the surface.

(Example 1)
Using a long copper foil 1 (rolled copper foil, thickness: 12 μm, width: 500 mm) as a base material, using a die coater on the roughened surface of the copper foil 1, the resin solution 1 prepared in Synthesis Example 1 was applied. It was applied uniformly so that the thickness after curing was 2.5 μm, and then dried by heating at 130° C. to remove the solvent. Next, the resin solution 2 prepared in Synthesis Example 2 was uniformly applied to the coating surface so that the thickness after curing would be 20 μm, and dried by heating at 120° C. to remove the solvent. Furthermore, the same resin solution 1 as that applied in the first layer was applied to the coated surface side uniformly so that the thickness after curing was 2.5 μm, and dried by heating at 130° C. to remove the solvent. C. to obtain a single-sided copper-clad laminate 1a having a polyimide film with a thickness of 25 .mu.m.

Using a heating and pressing device having a pair of pressure rolls, a polyimide coating roll 1 (polyimide coating layer thickness: 50 μm) is placed on the copper foil 1 side of the single-sided copper-clad laminate 1a, and single-sided copper-clad lamination is performed. A long copper foil 2 (electrolytic copper foil, thickness: 12 μm, width: 540 mm) is placed on the polyimide layer side of the plate 1a, and a metal roll is placed on the side opposite to the thermocompression bonding surface of the copper foil 2. did. While transporting these via guide rolls, under a nitrogen atmosphere, the roll surface temperature: 300 to 400 ° C., the linear pressure of the press roll: within the range of 38.6 to 115.8 kgf / cm, the transport speed: 4. A double-sided copper-clad laminate 1b was obtained by continuous thermocompression bonding under the condition of .0 m/min. The appearance of the copper foil surface on the coating side of the obtained double-sided copper-clad laminate 1b was good throughout, and the peel strength of the copper foil on the compression side was 1.6 kN/m.

(Comparative example 1)
A double-sided copper-clad laminate 1b' was obtained in the same manner as in Example 1, except that both pressure rolls were metal rolls. The appearance of the copper foil surface on the coating side of the obtained double-sided copper-clad laminate 1b' was partially defective, and the peel strength of the copper foil on the compression side was 1.2 kN/m.

The results of Example 1 and Comparative Example 1 are shown in Table 1.

(Example 2)
A double-sided copper-clad laminate 2b was obtained in the same manner as in Example 1, except that the polyimide-coated roll 2 (polyimide coating layer thickness: 75 μm) was used. The appearance of the copper foil surface on the coating side of the obtained double-sided copper-clad laminate 2b was good throughout, and the peel strength of the copper foil on the pressure bonding side was 1.6 kN/m.

(Example 3)
A double-sided copper-clad laminate 3b was obtained in the same manner as in Example 1, except that the polyimide-coated roll 3 (polyimide coating layer thickness: 25 μm) was used. The appearance of the copper foil surface on the coating side of the obtained double-sided copper-clad laminate 3b was good throughout, and the peel strength of the copper foil on the compression side was 1.6 kN/m.

(Example 4)
A double-sided copper-clad laminate 4b was obtained in the same manner as in Example 1, except that the polyimide-coated roll 4 (polyimide coating layer thickness: 20 μm) was used. The appearance of the copper foil surface on the coating side of the obtained double-sided copper clad laminate 4b was good throughout, and the peel strength of the copper foil on the compression side was 1.6 kN/m.

(Example 5)
A double-sided copper-clad laminate 5b was obtained in the same manner as in Example 1, except that the polyimide-coated roll 5 (polyimide coating layer thickness: 15 μm) was used. The appearance of the copper foil surface on the coating side of the obtained double-sided copper-clad laminate 5b was good throughout, and the peel strength of the copper foil on the compression side was 1.6 kN/m.

(Example 6)
A double-sided copper-clad laminate 6b was obtained in the same manner as in Example 1, except that the polyimide-coated roll 6 (polyimide coating layer thickness; 12 μm) was used. The appearance of the copper foil surface on the coating side of the obtained double-sided copper clad laminate 6b was good throughout, and the peel strength of the copper foil on the compression side was 1.6 kN/m.

(Example 7)
A double-sided copper-clad laminate 7b was obtained in the same manner as in Example 1, except that the polyimide-coated roll 7 (polyimide coating layer thickness: 10 μm) was used. The appearance of the copper foil surface on the coated side of the obtained double-sided copper-clad laminate 7b was good throughout, and the peel strength of the copper foil on the compression side was 1.6 kN/m.

(Example 8)
A double-sided copper-clad laminate 8b was obtained in the same manner as in Example 1, except that the polyimide-coated roll 8 (polyimide coating layer thickness: 8 μm) was used. The appearance of the copper foil surface on the coating side of the obtained double-sided copper-clad laminate 8b was good throughout, and the peel strength of the copper foil on the compression side was 1.6 kN/m.

(Example 9)
A double-sided copper-clad laminate 9b was obtained in the same manner as in Example 1, except that the polyimide-coated roll 9 (polyimide coating layer thickness: 100 μm) was used. The appearance of the copper foil surface on the coating side of the obtained double-sided copper clad laminate 9b was good throughout, and the peel strength of the copper foil on the compression side was 1.6 kN/m.

(Example 10)
Instead of placing the polyimide coating roll 1 on the copper foil 1 side of the single-sided copper clad laminate 1a in Example 1, a polyimide belt 10 (thickness: 20 μm, tensile strength: 400 MPa, tensile modulus ; 9 GPa, seamless type) was arranged in the same manner as in Example 1 to obtain a double-sided copper-clad laminate 10b. The appearance of the copper foil surface on the coating side of the obtained double-sided copper-clad laminate 10b was good throughout, and the peel strength of the copper foil on the compression side was 1.6 kN/m. The contact time of the polyimide belt 10 with the pressure roll was 2 seconds.

(Example 11)
Instead of placing the polyimide coating roll 1 on the copper foil 1 side of the single-sided copper clad laminate 1a in Example 1, a commercially available polyimide film 11 (thickness: 25 μm) from which moisture was removed by preheating was placed. A double-sided copper-clad laminate 11b was obtained in the same manner as in Example 1. The appearance of the copper foil surface on the coating side of the obtained double-sided copper-clad laminate 11b was good throughout, and the peel strength of the copper foil on the compression side was 1.6 kN/m. The insertion angle of the polyimide film 11 into the pressure roll was 70°.

As described above in detail, according to the method for manufacturing a metal-clad laminate of the present embodiment, the polyimide film evenly fills the irregularities on the surface of the metal foil, and the polyimide film and the metal foil are firmly bonded. A bonded metal-clad laminate is obtained. By using the metal-clad laminate thus produced as a material for circuit boards such as FPCs, it is possible to produce circuit boards having excellent adhesion between the miniaturized wiring and the insulating resin layer. Therefore, according to the present invention, the yield and reliability of circuit boards and electronic products using circuit boards can be improved.

Although the embodiments of the present invention have been described in detail for purposes of illustration, the present invention is not limited to the above embodiments.

10, 10A Polyimide film 20 Metal foil 30 Pressure roll (coated pressure roll) 31 Metal roll 33 Adhesive layer 35 Polyimide coating layer 40 Pressure roll 50 Coating layer 50A... cyclic polyimide film, 50B... long polyimide film, 61... application means, 63... resin solution, 71... base material, 73... polyimide layer, 80A, 80B... guide roll, 90A... unwinding roll, 90B... Winding roll, 100, 100A... Metal-clad laminate

Claims (8)

A method for producing a metal-clad laminate by thermally compressing the polyimide film and the metal foil by superimposing the polyimide film and the metal foil and continuously passing them through a pair of pressure rolls,
The polyimide film is a single-sided copper-clad laminate including a copper foil and a polyimide layer laminated on one side of the copper foil, and the metal foil is thermocompression bonded to the polyimide layer side. can be,
Of the pair of pressure rolls, the pressure surface of one of the pressure rolls is covered with a film-like cushioning material that can move in synchronization with the one-side pressure roll , and the film-like cushioning material is A metal-clad laminate characterized in that it is placed only on the copper foil side of the single-sided copper-clad laminate and subjected to thermocompression bonding, and the film-like cushioning material includes a non-thermoplastic polyimide layer made of non-thermoplastic polyimide. Board manufacturing method. 2. The method for producing a metal-clad laminate according to claim 1, wherein the film-like cushioning material forms a covering layer that covers the surface of the pressure roll on one side in the circumferential direction. 3. The method for producing a metal-clad laminate according to claim 2, wherein the pressure roll on one side is a coated pressure roll having the coating layer, and the pressure roll on the other side is a metal roll. 4. The method for producing a metal-clad laminate according to claim 3, wherein the metal roll is placed on the metal foil side. 2. The method of manufacturing a metal-clad laminate according to claim 1, wherein said film-like cushioning material is formed in a ring shape and is rotatable by means of said pressure roll on one side and a plurality of guide rolls. 2. The method for manufacturing a metal-clad laminate according to claim 1, wherein the film-like cushioning material is formed in a long length and is conveyed in a roll-to-roll manner. 7. The method for producing a metal-clad laminate according to any one of claims 1 to 6, wherein the film-like cushioning material has a thickness in the range of 1 to 200 µm. 1. The polyimide film comprises a single layer or multiple layers of polyimide layers, at least one layer of which is a non-thermoplastic polyimide layer, and at least a surface of which is thermally bonded to the metal foil is a thermoplastic polyimide layer. 8. The method for producing a metal-clad laminate according to any one of 7 above.

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