JP7173221B2 - Double-sided plated laminate - Google Patents

Description

The present invention relates to a double-sided plated laminate and a method for producing a double-sided plated laminate.

In addition to mobile communications such as mobile phones and car phones, the demand for smaller and lighter portable electronic devices such as tablets, e-book terminals, smartphones, MP3 players, and electronic game consoles is increasing. Expectations for high-density mounting, which is equipped with high density in Along with this, multilayering of printed wiring boards, narrowing of wiring pitches, miniaturization of via holes, and miniaturization of IC packages with a large number of pins are being promoted. Passive elements such as capacitors and resistors are also being miniaturized, integrated, and surface-mounted.

In particular, the technique of directly mounting electronic components on the surface of a printed wiring board or the like, or in the inside thereof, not only achieves high-density mounting, but also contributes to improved reliability. For these reasons, the required level of dimensional accuracy of the printed wiring board, that is, the accuracy of the wiring pitch, is becoming higher, and the printed wiring board is also required to have dimensional thermal stability.

As a printed wiring board, a plastic wiring board having a metal layer or the like arranged on the surface of a plastic film is generally used.

As a method of manufacturing a plastic wiring board, the following two typical manufacturing methods are known.

As a first method, there is a method of laminating a metal foil and a plastic film used for conductors forming a circuit by a thermocompression bonding (laminating) method.

As a second method, a thin seed layer and a first metal layer are formed on a plastic film by a dry plating method such as a sputtering method, an ion plating method, or a vacuum deposition method, and then electroless plating is performed thereon. Alternatively, there is a metallizing method in which a second metal layer is further formed by a wet plating method such as an electrolytic plating method.

A specific example of a method for manufacturing a plastic wiring board by the metallizing method is disclosed in Patent Document 1 and Patent Document 2.

For example, in Patent Document 1, a metal seed layer made of nickel, chromium, or an alloy thereof is formed on a thermoplastic liquid crystal polymer film using a sputtering method. An example is disclosed in which a copper conductive layer is then formed, and the copper conductive layer is formed on the copper conductive layer by electrolytic copper plating, electroless copper plating, or a combination of both.

By the way, a plastic wiring board may be required to be a double-sided plated laminate in which metal layers are arranged on both sides of a plastic film in order to mount electronic components and the like at high density.

For example, Patent Document 3 discloses a double-sided metal clad laminate in which metal sheets are bonded to both surfaces of a thermoplastic liquid crystal polymer film.

A double-sided plated laminate can also be produced by a metallizing method.

JP-A-2005-297405 JP 2009-026990 A Japanese Patent Application Laid-Open No. 2006-137011

However, when the metal laminate of the double-sided plated laminate in which a seed layer, a first metal layer and a second metal layer are laminated in that order on both sides of a plastic film is patterned and the plastic film is exposed, the plastic film absorbs moisture and expands. , there was a problem that a large dimensional change occurs.

In view of the above problems of the prior art, in one aspect of the present invention, a double-sided plated laminate in which a metal laminate disposed on the surface of a plastic film is etched to suppress dimensional change even when a part of the plastic film is exposed The purpose is to provide the body.

In order to solve the above problems, in one aspect of the present invention,
a plastic film;
a seed layer disposed directly on both sides of the plastic film;
a first metal layer disposed on the seed layer;
A double-sided plated laminate having a second metal layer disposed on the first metal layer,
The water absorption rate of the plastic film at 23.0° C.±2.0° C. is 70% or more and less than 100%,
The dimensional change rate of MD and TD according to IPC-TM-650, 2.2.4, Method B is within ±0.05%,
Provide a double-sided plated laminate having a dimensional change rate in MD and TD according to IPC-TM-650, 2.2.4, Method C within ±0.05%.

According to one aspect of the present invention, it is possible to provide a double-sided plated laminate in which a dimensional change is suppressed even when the metal laminate disposed on the surface of the plastic film is etched to partially expose the plastic film. can.

BRIEF DESCRIPTION OF THE DRAWINGS The cross-sectional schematic diagram of the double-sided plating laminated body which concerns on embodiment of this invention. Explanatory drawing of the structural example of a continuous electroplating apparatus. Explanatory drawing of the structural example of the film-forming apparatus using the dry plating method.

An embodiment of the plating apparatus of the present invention will be described below.
[Double-sided plated laminate]
The double-sided plated laminate of this embodiment includes a plastic film, a seed layer directly disposed on both sides of the plastic film, a first metal layer disposed on the seed layer, and a and a second metal layer.
The double-sided plated laminate of the present embodiment has a dimensional change rate of ±0.05% or less in MD and TD according to IPC-TM-650, 2.2.4, Method B, and IPC-TM-650, 2.2.4. 2.4 The dimensional change rate of MD and TD by Method C can be within ±0.05%.

First, the structure of the double-sided plated laminate of this embodiment will be described with reference to FIG. FIG. 1 schematically shows a cross-sectional view of the double-sided plated laminate 10 in a plane perpendicular to the main surface of the plastic film 11 .

The double-sided plated laminate 10 has a seed layer 12A, a first metal layer 13A, and a second metal layer 14A laminated in that order on one surface 11a of the plastic film 11 from the plastic film 11 side. Also on the other surface 11b of the plastic film 11, a seed layer 12B, a first metal layer 13B, and a second metal layer 14B are laminated in that order from the plastic film 11 side.

That is, it has a structure in which seed layers 12A and 12B, first metal layers 13A and 13B, and second metal layers 14A and 14B are laminated in this order on both surfaces (both main surfaces) of the plastic film 11, respectively.

The seed layers 12A and 12B are directly arranged on both sides of the plastic film 11. As shown in FIG. That is, they are arranged without an adhesive or the like. Also, between the layers, that is, between the seed layers 12A, 12B and the first metal layers 13A, 13B, and between the first metal layers 13A, 13B and the second metal layers 14A, 14B It can be configured to be in direct contact without intervening.

Each member will be described in detail below.

First, the plastic film will be explained.

The material of the plastic film is not particularly limited, and films made of various plastic materials can be used.

Examples of plastic film materials include heat-resistant resins such as polyimide and polyethylene terephthalate, polyamide-based resins, polyester-based resins, polytetrafluoroethylene-based resins, polyphenylene sulfide-based resins, polyethylene naphthalate-based resins, and liquid crystal polymer-based resins. One or more selected resins can be used.

A material obtained by mixing two or more resins can also be used as the material of the plastic film.

As a material for the plastic film, polyimide resin is preferably used because of its excellent heat resistance and insulating properties. That is, the plastic film is preferably a polyimide film.

Polyimide has a structure represented by chemical formula (1). In the chemical formula (1), when R and R' are aromatic, it is called an aromatic polyimide and is widely used industrially. Aromatic polyimides are generally obtained by a polycondensation reaction between an aromatic acid anhydride and a diamine. Therefore, depending on the combination of the acid component and the diamine component, polyimides with various structures can be obtained, and physical properties such as heat resistance may vary depending on the chemical (molecular) structure. However, when polyimide is used as the material of the plastic film of the double-sided plated laminate of the present embodiment, the structure of the polyimide is not particularly limited, and various types of polyimide can be used.

例えば化学式（２）、および／または化学式（３）で表される構造を有するポリイミドを、プラスチックフィルムの材料として用いることができる。

For example, polyimide having a structure represented by chemical formula (2) and/or chemical formula (3) can be used as the material of the plastic film.

Chemical formula (2) is an acid component pyromellitic dianhydride (PMDA) and a diamine component 4,4'-diaminodiphenyl ether (alias: 4,4'-oxybisbenzenamine, 4,4'-oxydi Aniline=ODA) can be prepared by polymerizing in an organic solvent.

化学式（３）は、酸成分としてビフェニルテトラカルボン酸二無水物（ＢＰＤＡ）を使用しており、ベンゼン環とイミド結合のみの分子構造を有している。このＢＰＤＡを酸成分に用いることで、ＰＭＤＡを用いた化学式（２）の構造を有するポリイミドと比べて、より剛直な構造になっている等、特性に違いがみられる。

Chemical formula (3) uses biphenyltetracarboxylic dianhydride (BPDA) as the acid component and has a molecular structure consisting only of benzene rings and imide bonds. By using this BPDA as an acid component, the polyimide has a more rigid structure than the polyimide having the structure of the chemical formula (2) using PMDA.

化学式（３）のように、イミド結合により直接結合された芳香族環は共役構造を取るため、上述のように剛直で強固な構造をもつ。また、芳香族環が同一平面に配列して分子鎖が互いに密に充填（パッキング）され、極性の高いイミド結合が強い分子間力を有することから、分子鎖間の結合力も強固となる。

As shown in chemical formula (3), the aromatic rings directly linked by the imide bond have a conjugated structure, and thus have a rigid and strong structure as described above. In addition, since the aromatic rings are arranged on the same plane and the molecular chains are densely packed (packed), and the highly polar imide bond has a strong intermolecular force, the bonding force between the molecular chains is also strong.

When a polyimide film is used as the plastic film, a commercially available polyimide film can also be used. ) series, etc. can also be used.

Although the water absorption rate of the plastic film is not particularly limited, it is preferably, for example, 1.0% or more and 1.9% or less. The water absorption rate referred to here is the water absorption amount (saturated water absorption amount) when immersed in water until it is saturated by the A method specified in JIS K 7209 (2000), and the water absorption amount is used. It means the calculated water absorption (saturated water absorption).

For the plastic film, for example, heat treatment may be performed in advance, and surface treatment such as plasma irradiation may be performed on one side or both sides. Adhesion to the seed layer or the like can be enhanced by surface treatment.

Although the thickness of the plastic film is not particularly limited, it is preferably 5 μm or more, more preferably 10 μm or more. The upper limit of the thickness of the plastic film is also not particularly limited, but if it is excessively thick, there is a possibility that the handleability of the double-sided plated laminate may deteriorate, so it is preferably 80 μm or less, for example.

Next, the configuration of the seed layer will be described.

The seed layer has the function of enhancing adhesion between, for example, the plastic film and the first metal layer.

Although the material of the seed layer is not particularly limited, it is preferable to use, for example, a metal material from the viewpoint of enhancing adhesion to the first metal layer. Materials for the seed layer include, for example, nickel, chromium, molybdenum, titanium, vanadium, tin, gold, silver, zinc, palladium, ruthenium, rhodium, iron, aluminum, lead, carbon, and lead-tin solder alloys. It is preferably a metal or alloy containing one or more of these metals. In particular, the material of the seed layer is more preferably one selected from nickel, chromium, an alloy containing nickel, an alloy containing chromium, and an alloy containing nickel and chromium. A Cr alloy is more preferable. That is, it is more preferable that the seed layer is made of a Ni--Cr alloy. Even if the seed layer is made of a Ni--Cr alloy, it does not exclude the inclusion of unavoidable components and the like that are mixed in, for example, the manufacturing process.

Although the thickness of the seed layer is not particularly limited, it is preferably, for example, 3 nm or more and 50 nm or less. This is because when the seed layer has a thickness of less than 3 nm, it is corroded by the etchant during patterning to form wiring and the like, and the etchant penetrates between the seed layer and the plastic film, causing the wiring to float. This is because it may be lost. On the other hand, if the thickness of the seed layer exceeds 50 nm, the portion of the seed layer that should be removed cannot be completely removed by etching when patterning is performed to form a wiring or the like. This is because there is a risk of occurrence.

Next, the first metal layer and the second metal layer will be described.

Materials for the first metal layer and the second metal layer are not particularly limited, and a material having electrical conductivity suitable for the application can be selected. is preferably a copper alloy of Cu and at least one or more metals selected from Ni, Mo, Ta, Ti, V, Cr, Fe, Mn, Co, W, or a material containing copper . Alternatively, the first metal layer and the second metal layer may be copper layers made of copper.

The first metal layer and the second metal layer can be made of the same material, or can be made of different materials.

In particular, since copper is commonly used as a material for wiring boards, the first metal layer and the second metal layer are preferably layers made of copper, that is, copper layers. Note that even if the first metal layer and the second metal layer are layers made of copper, it is not excluded that they contain unavoidable components mixed in, for example, the manufacturing process.

The thickness of the first metal layer and the second metal layer is not particularly limited. can be arbitrarily selected according to the conditions of For example, the sum of the thickness of the first metal layer and the thickness of the second metal layer is preferably 0.1 μm or more and 20 μm or less.

Methods for forming wiring using the double-sided plated laminate of the present embodiment include a subtractive method and a semi-additive method. For example, when wiring is formed by a semi-additive method, a first metal layer and a second metal layer are selectively grown to process the wiring.

By setting the sum of the thickness of the first metal layer and the thickness of the second metal layer to 0.1 μm or more, for example, when wiring is formed on the double-sided plated laminate of the present embodiment to form a wiring board, This is because a sufficient current can be supplied to the first metal layer and the second metal layer forming the wiring.
On the other hand, by setting the sum of the thickness of the first metal layer and the thickness of the second metal layer to 20 μm or less, it is possible to maintain a sufficiently high production even when performing wiring processing by etching, and the wiring board can be used as a wiring board. This is because the total thickness of is also sufficiently suppressed, which is preferable.

More preferably, the sum of the thickness of the first metal layer and the thickness of the second metal layer is 0.3 μm or more and 15 μm or less.

Although the thickness of the first metal layer alone is not particularly limited, it is preferably 10 nm or more and 300 nm or less, for example. As will be described later, the second metal layer can be formed, for example, by a wet plating method. By setting the thickness of the first metal layer to 10 nm or more, a sufficient amount of power supply can be secured and uniform This is because the second metal layer can be formed. In addition, by setting the thickness of the first metal layer to 300 nm or less, the seed layer and the first metal layer can sufficiently transmit moisture, so when manufacturing the double-sided plated laminate of this embodiment, This is because the plastic film can be made to sufficiently absorb moisture and the dimensional stability can be enhanced.

As described above, the double-sided plated laminate of this embodiment can have a dimensional change rate in MD and TD according to IPC-TM-650, 2.2.4, Method B within ±0.05%. Also, the dimensional change rate of MD and TD according to IPC-TM-650, 2.2.4, Method C can be within ±0.05%.

The dimensional change rates of MD and TD according to IPC-TM-650, 2.2.4, Method B and Method C are defined in IPC-TM-650, No. Means the dimensional change rates of MD and TD evaluated by the test methods of Method B and Method C disclosed in 2.2.4 (Revision C).

MD means machine dimension, which means the longitudinal direction of the double-sided plated laminate. Also, TD means a transverse dimension (horizontal axis direction), which means a direction orthogonal to MD.

In the index of dimensional change rate, shrinkage is indicated by a negative value, and elongation is indicated by a positive value.

Then, according to the above Method B, the seed layer, the first metal layer, and the second metal layer of the double-sided plated laminate of the present embodiment (hereinafter, these layers are also collectively referred to as "metal laminate") The dimensional change rate during etching can be evaluated. Further, according to Method C, the dimensional change rate can be evaluated after the metal laminate is etched and then subjected to heat treatment at 150° C. for 30 minutes.

Therefore, according to the double-sided plated laminate of the present embodiment, in which the MD and TD dimensional change rates of Method B and Method C are within ±0.05%, the metal laminate disposed on the surface of the plastic film This means that even when the body is etched and part of the plastic film is exposed, dimensional changes are stably suppressed. It also means that even when the metal laminate is etched and heated in a state where a part of the plastic film is exposed, the dimensional change can be suppressed.

In the double-sided plated laminate of the present embodiment, the dimensional change rate in MD and TD according to Method B is more preferably within ±0.04%. Further, in the double-sided plated laminate of the present embodiment, the dimensional change rate in MD and TD according to Method C is more preferably within ±0.04%.

According to the double-sided plated laminate of the present embodiment described above, even if the metal laminate disposed on the surface of the plastic film is etched to form wiring and the like, and a part of the plastic film is exposed, Dimensional change can be suppressed. In addition, even when wiring or the like is formed and the plastic film is partially exposed and heated, the dimensional change can be suppressed.

Therefore, the double-sided plated laminate of the present embodiment can be suitably used in various applications that particularly require suppression of dimensional change, such as wiring boards for high-density mounting. More specifically, for example, the double-sided plated laminate of the present embodiment is very useful as a material for a wiring board that joins, electrically connects, and mechanically fixes electronic components.
[Manufacturing method of double-sided plated laminate]
Next, a configuration example of the method for manufacturing the double-sided plated laminate of the present embodiment will be described. The above-described double-sided plated laminate can be produced by the method for producing a double-sided plated laminate according to the present embodiment. For this reason, the description of the matters already described when describing the double-sided plated laminate is partially omitted.

One structural example of the manufacturing method of the double-sided plated laminate of the present embodiment can have the following steps.

Moisture absorption step in which the seed layer and the first metal layer formed by the dry plating method are directly arranged on both sides of the plastic film in that order, and the plastic film absorbs moisture so that the water absorption rate of the plastic film at room temperature is 70% or more. .

A second metal layer forming step of forming a second metal layer by a wet plating method after the moisture absorption step.

The inventors of the present invention have found that in a double-sided plated laminate in which metal laminates are formed on both sides of a plastic film, the metal laminate disposed on the surface of the plastic film is etched to expose a part of the plastic film. , and investigated the cause of the large dimensional change, and found the following points.

A double-sided plated laminate, for example, has a structure in which a seed layer, a first metal layer, and a second metal layer are laminated on both sides of a plastic film in this order from the plastic film side. The first metal layer can be formed by dry plating, and the second metal layer can be formed by wet plating.

When the first metal layer is formed by dry plating, the plastic film is removed before or in parallel with the dry plating process in order to prevent contamination of the metal laminate with moisture from the plastic film and other gas components. It is common to heat-dry the substrate containing the substrate under reduced pressure. Moisture and other degassing components can be removed from the plastic film by such an operation. Therefore, immediately after the formation of the first metal layer, the plastic film has almost no moisture, for example, it is dried to an absolute dry state, contains less moisture, and is in a shrunk state. Since the size of the plastic film is not sufficiently fixed with the seed layer and the first metal layer formed, the plastic film can shrink and expand.

When the second metal layer is formed by a wet plating method, the second metal layer is formed by electroplating or electroless plating in a plating solution. The laminate with the first metal layer is immersed in a plating solution. At this time, the total thickness of the seed layer and the thickness of the first metal layer is very thin, for example, 350 nm or less. , the seed layer, and the first metal layer, the plastic film absorbs moisture. However, when forming the second metal layer, if the seed layer and the first metal layer are arranged on both sides of the plastic film, the moisture absorption rate of the plastic film slows down. During this time, the amount of water contained in the plastic film does not reach saturation or near saturation.

Then, the dimension of the plastic film is fixed by forming the second metal layer. Therefore, when the seed layer, the first metal layer, and the second metal layer are partially removed by etching or the like in order to form wiring or the like, and the surface of the plastic film is exposed, moisture absorption progresses from the exposed portion. However, a large dimensional change occurred.

Therefore, in one configuration example of the method for manufacturing a double-sided plated laminate of the present embodiment, as described above, the seed layer and the first metal layer formed by the dry plating method are directly arranged on both surfaces in that order. It can have a moisture absorption step of absorbing moisture to the plastic film having a water absorption rate of 70% or more of the water absorption rate of the plastic film at room temperature.

The water absorption rate of the plastic film at room temperature as used herein refers to the water absorption amount (saturated water absorption amount) when immersed in water until it is saturated by Method A specified in JIS K 7209 (2000). It means the water absorption rate (saturated water absorption rate) calculated using the water absorption amount. Therefore, normal temperature means 23.0°C±2.0°C.

As already mentioned, the sum of the thickness of the seed layer and the thickness of the first metal layer is very thin, so even if the seed layer and the first metal layer are located on both sides of the plastic film, the plastic The film can absorb moisture. By carrying out the moisture absorption step in this manner, the plastic film has a water absorption rate (saturated water absorption rate) of 70% or more at room temperature. Since the moisture content of the plastic film further increases in the second metal layer forming step, which will be described later, the moisture content of the plastic film is saturated or saturated when the second metal layer forming step is completed. be in the vicinity.

Therefore, even if the opening is formed by etching the metal laminate including the seed layer, the first metal layer, and the second metal layer after forming the second metal layer, and the plastic film is exposed from the opening, Since the plastic film hardly absorbs moisture, the dimensional change of the plastic film due to moisture absorption can be suppressed. Therefore, it is possible to suppress the dimensional change of the double-sided plated laminate.

In the moisture absorption step, there is no particular limitation on the method by which the seed layer and the first metal layer formed by the dry plating method absorb (humidify) the plastic film directly arranged on both sides in that order.

For example, in the moisture absorption step, a plastic film having a seed layer and a first metal layer formed by dry plating on both sides in that order is wrapped in an atmosphere with a humidity of 60% or more and 100% or less. By alternately conveying, the plastic film can be made to absorb moisture. In the moisture absorption step, the upper limit of the humidity of the atmosphere when rewinding and conveying the plastic film having the seed layer and the first metal layer formed by the dry plating method on both sides in that order is as described above. For example, it can be 100% or less, but by suppressing condensation of moisture on the surface of the first metal layer, the operation after the moisture absorption step can be particularly easy, so for example, it is 80% or less. is more preferred.

In this specification, humidity means relative humidity.

As described above, in the moisture absorption step, the temperature of the atmosphere when rewinding and conveying the plastic film having the seed layer and the first metal layer formed by the dry plating method on both sides in that order is Although not particularly limited, it is preferably 23°C ± 2°C, for example.

In the moisture absorption step, a plastic film having a seed layer and a first metal layer formed by a dry plating method on both sides in that order is wound into a roll, for example. The plastic film can also be made to absorb moisture by holding it in an atmosphere in which the is 60% or more and 100% or less. However, in this case, it is necessary to keep the plastic film in the above atmosphere for a long time, for example, 24 hours or more, in order to absorb moisture so that the water absorption rate of the plastic film at room temperature is 70% or more. Therefore, from the viewpoint of productivity, it is preferable to carry out rewinding and conveying under a predetermined humidity atmosphere as described above.

Also, in the moisture absorption step, the plastic film having the seed layer and the first metal layer formed by the dry plating method formed on both sides in that order can be immersed in water to absorb moisture.

As described above, in the moisture absorption step, when the seed layer and the first metal layer formed by the dry plating method are sequentially formed on both sides of the plastic film and the plastic film is immersed in water, the temperature of the water is Although not particularly limited, it is preferably 23°C ± 2°C, for example.

In the moisture absorption step, the seed layer and the first metal layer formed by the dry plating method are limited to one method for moisture absorption (humidity conditioning) of the plastic film directly arranged on both sides in that order. not something. For example, a plastic film having a seed layer and a first metal layer formed by dry plating on both sides in that order is rewound and transported in an atmosphere with a humidity of 60% or more and 100% or less. In addition, a combination of methods of immersion in water may be used.

Then, as described above, one structural example of the method for manufacturing a double-sided plated laminate of the present embodiment includes a second metal layer forming step of forming a second metal layer by a wet plating method after the moisture absorption step described above. can have

In the second metal layer forming step, the second metal layer can be formed on each side of the plastic film. However, from the viewpoint of productivity, it is preferable to simultaneously form the second metal layer on both surfaces of the plastic film in the second metal layer forming step. That is, it is preferable to simultaneously form the second metal layer on the first metal layer formed on one side of the plastic film and on the first metal layer formed on the other side of the plastic film.

In the second metal layer forming step, the specific conditions for forming the second metal layer by the wet plating method are not particularly limited. For example, the film can be formed by an electrolytic plating method or an electroless plating method.

When forming the second metal layer by electroplating, for example, the continuous electroplating apparatus 20 shown in FIG. 2 can be used. In the electroplating treatment, as described above, either single-sided film formation or double-sided simultaneous film formation may be performed. 1 shows a configuration example of an electrolytic plating apparatus.

FIG. 2 shows a cross-sectional view of the continuous electrolytic plating apparatus 20 in a plane parallel to the conveying direction of the double-sided plated laminate precursor F1.

The continuous electrolytic plating apparatus 20 includes an unwinding roll 21 for unwinding a double-sided plated laminate precursor F1, which is a plastic film having a seed layer and a first metal layer arranged in that order on both sides, and a plating solution filled. plating solution tank 22, anodes (anode) 23a to 23p arranged parallel to each other inside the plating solution tank 22, and double-sided plated laminate precursor F1 inside the plating solution tank 22 up and down in the conveying direction. Immersion rolls 24a to 24d to be reversed, power supply rolls 25a to 25e outside the plating solution tank 22 to supply electric power to the double-sided plated laminate precursor F1, and electroplating to the double-sided plated laminate precursor F1. A winding roll 26 is provided for winding the double-sided plated laminate F2 obtained by the above.

The unwinding roll 21, the dipping rolls 24a to 24d, the power supply rolls 25a to 25e, and the winding roll 26 constitute a means for transporting the double-sided plated laminate precursor F1, whereby the double-sided plated laminate precursor F1 is While keeping the width direction horizontal, it can be transported in the longitudinal direction by a roll-to-roll method and immersed in the plating solution multiple times.

The feed roll and the adjacent anode form an electrical pair. Specifically, between the power supply roll 25a and the anodes 23a and 23b, between the power supply roll 25b and the anodes 23c to 23f, between the power supply roll 25c and the anodes 23g to 23j, and between the power supply roll 25d and the anodes 23k to 23n. and between the feed roll 25e and the anodes 23o and 23p, respectively. Each pair is powered by an independent power supply (not shown), with separate current control between different pairs.

The anodes (anodes) 23a to 23p are not particularly limited, and can be arbitrarily selected according to the plating solution to be used. For example, soluble anodes and insoluble anodes can be used. The plating solution to be put in the plating solution bath 22 can be arbitrarily selected according to the composition of the second metal layer. can be used.

When a copper sulfate plating solution is used as the plating solution, the copper sulfate plating solution can contain copper sulfate, sulfuric acid, trace amounts of chloride ions, various additives, etc., and its composition can be appropriately selected according to the purpose. can. When a copper sulfate plating solution is used as the plating solution, copper ions in the plating solution are reduced, and a copper layer having a desired thickness can be easily formed on the seed layer of the double-sided plated laminate precursor F1. .

In addition, the method for manufacturing the double-sided plated laminate of the present embodiment can have arbitrary steps other than the above-described moisture absorption step and second metal layer formation step.

For example, the following steps for producing a double-sided plated laminate precursor in which the seed layer and the first metal layer are directly arranged in that order on both sides of the plastic film supplied to the moisture absorption step.

A plastic film preparation process for preparing a plastic film.
A seed layer forming step for forming seed layers on both sides of the plastic film.

a first metal layer forming step of forming a first metal layer on the seed layer;

The plastic film preparation step is a step of preparing a plastic film to be supplied to the seed layer forming step, and specific operations are not particularly limited. For example, a plastic film may be cut into a desired size, the plastic may be subjected to heat treatment or the like, or both surfaces thereof may be subjected to surface treatment such as plasma irradiation.

In the seed layer forming step, a seed layer can be formed on the surface of the plastic film. Although the method for forming the seed layer is not particularly limited, it is preferable to use a dry plating method such as a vapor deposition method or a sputtering method. As a method for forming the seed layer, it is more preferable to use a sputtering method because it is particularly easy to control the film thickness. In the seed layer forming step, the specific conditions for forming the seed layer are not particularly limited, and can be arbitrarily selected according to the material of the seed layer, the performance required of the seed layer, and the like. .

In the seed layer forming step, the seed layers can be formed on both sides of the plastic film at the same time, but can also be formed on one side at a time.

In the first metal layer forming step, a first metal layer can be formed on the seed layer. The method of forming the first metal layer is also not particularly limited, but it is preferable to use a vapor deposition method or a dry plating method such as a sputtering method. As a method for forming the first metal layer, it is more preferable to use a sputtering method because it is particularly easy to control the film thickness.

In the first metal layer forming step, the specific conditions for forming the first metal layer are not particularly limited. can be selected arbitrarily.

In the first metal layer forming step, the first metal layers may be simultaneously formed on the seed layers respectively formed on both sides of the plastic film, or the first metal layers may be formed on one side at a time.

Here, a configuration example of a film forming apparatus using a dry plating method, which can be suitably used when forming the seed layer and the first metal layer, will be described with reference to FIG.

FIG. 3 is a diagram schematically showing the configuration of the film forming apparatus 30. As shown in FIG.

A film forming apparatus 30 in FIG. 3 is an apparatus for forming a film by a sputtering method, and is also called a sputtering film coater. As will be described later, by changing the configuration of the magnetron sputtering cathodes 41a to 41d, etc., it is also possible to make a film forming apparatus using or using film forming methods other than the sputtering method.

The film forming apparatus 30 holds a film-forming object, which is continuously transported in a roll-to-roll manner, on a holding surface of a can roll 32 as holding means, that is, on an outer peripheral surface of the film-forming object. A film can be formed by depositing film-forming particles emitted from the film-forming means toward a film-forming object on the surface of the film-forming object.

In addition, a cooling means (not shown) can be provided inside the can roll 32, so that even in the case of the dry plating method with a high thermal load, continuous can be processed.

Each element constituting the film forming apparatus 30 and the film forming procedure of the seed layer, the first metal layer, etc. will be specifically described.

An unwinding roll 33 and a winding roll 34 are provided in a vacuum chamber 31 as a decompression container. You can carry things. The shape and material of the vacuum chamber 31 are not particularly limited as long as they can withstand the reduced pressure, and various types can be used.

A conveying route of the plastic film F will be described. First, a long plastic film F, which is an object to be deposited, is supplied from the feed roll 33 . When only the first metal layer is formed, a long plastic film F having a seed layer formed on one or both surfaces thereof can be used.

The transport path from the unwinding roll 33 to the can roll 32 includes, for example, a free roll 35 that guides the plastic film F, a tension sensor roll 36 that measures the tension of the plastic film F, and a tension sensor roll 36 that measures the tension of the plastic film F. A motor-driven feed roll 37, which introduces the plastic film F fed from the sensor roll 36 into the can roll 32, can be arranged in this order.

Also, in the transport path from the can roll 32 to the take-up roll 34, the feed roll 38 driven by a motor and the tension sensor roll 39 for measuring the tension of the plastic film F are provided. , and the free roll 40 for guiding the plastic film F can be arranged in this order.

The feed rolls 37 and 38 provided in the vicinity of the can roll 32 are preferably rotationally driven by a motor so that the peripheral speed of the can roll 32 can be adjusted. Further, the unwinding roll 33 can be configured to keep the tension balance of the plastic film F by using torque control by a powder clutch or the like. With this configuration, the plastic film F unwound while its tension is adjusted is cooled by the feed rolls 37 and 38 rotating in conjunction with the can roll 32 in close contact with the outer peripheral surface of the can roll 32. , is dry-plated and can be taken up by a motor-driven take-up roll 34 .

Plate-shaped magnetron sputtering cathodes 41a to 41d, which are film forming means, are arranged along the transport path of the plastic film F at positions facing the outer peripheral surface of the can roll 32. As shown in FIG. As a result, the surface of the plastic film F being transported can be subjected to a sputtering film forming process, which is a dry plating process.

The dry plating process performed by the film forming apparatus 30 is not limited to the above sputtering method. Sputtering methods can also be used in combination with other vacuum deposition methods such as CVD (chemical vapor deposition), ion plating, vacuum deposition, and the like. Also, instead of the sputtering method, other vacuum deposition methods described above can be used. When using these other vacuum film forming methods, predetermined vacuum film forming means can be provided in place of some or all of the magnetron sputtering cathodes 41a to 41d.

Various means (not shown) can be optionally connected to the vacuum chamber 31 in addition to the means described above. For example, exhaust means such as a dry pump, turbo-molecular pump, and cryo coil, and various atmosphere control means such as gas supply means for supplying gas into the vacuum chamber 31 can be connected. Further, a heater (not shown) or the like can be installed along the transport path of the plastic film so as to remove moisture from the plastic film supplied from the unwinding roll 33, for example.

When the seed layer and the first metal layer are formed on both sides of the plastic film by the film forming apparatus 30 described above, for example, the seed layer and the first metal layer are first formed on one side of the plastic film. can be formed. Then, after rewinding, the other side of the plastic film may be subjected to the same treatment to form a seed layer and a first metal layer on both sides of the plastic film.

Both the seed layer and the first metal layer can be preferably formed by dry plating. Therefore, for example, the first metal layer can be continuously processed, that is, continuously formed, in the vacuum chamber in which the seed layer was formed.

A configuration example in which the seed layer and the first metal layer are continuously formed using the film forming apparatus 30 described above will be described.

First, a plastic film is attached to the unwinding roll 33 .

Further, for example, a seed layer target having a composition corresponding to the seed layer is attached to the magnetron sputtering cathode 41a, and a first metal layer target having a composition corresponding to the first metal layer is attached to the magnetron sputtering cathodes 41b to 41d. .

Next, the inside of the vacuum chamber 31 is evacuated by an evacuation means (not shown), and after the pressure inside the vacuum chamber 31 is reduced to about 10 ⁻⁴ Pa, a sputtering gas is introduced by a gas supply means (not shown) to reduce the inside of the vacuum chamber 31 to zero. . Adjust the pressure to about 1 Pa or more and 10 Pa or less. As the sputtering gas, an inert gas such as argon can be suitably used, and a gas such as oxygen can be added depending on the purpose.

By applying a voltage to the magnetron sputtering cathodes 41a to 41d while supplying the plastic film from the unwinding roll 33, the seed layer and the first metal layer can be laminated on the plastic film.

Next, another configuration example of the method for manufacturing the double-sided plated laminate of the present embodiment will be described.

Another configuration example of the method for manufacturing a double-sided plated laminate according to the present embodiment can have the following steps.

A seed layer and a first metal layer formed by a dry plating method are directly arranged on one surface of a plastic film in that order. A second metal layer is formed by a wet plating method on the first metal layer. a second metal layer first forming step;
A seed layer/first metal layer forming step of forming a seed layer and a first metal layer on the other surface of the plastic film by dry plating.
a second metal layer forming step of forming a second metal layer by wet plating on the first metal layer formed on the other surface of the plastic film in the seed layer/first metal layer forming step;

In another configuration example of the method for producing a double-sided plated laminate of the present embodiment, a seed layer and a first metal layer are formed in advance on one surface of the plastic film, and on the first metal layer A second metal layer is formed (second metal layer first forming step). The method for producing the second metal layer is the same as the second metal layer forming step in the above-described one configuration example of the method for producing a double-sided plated laminate, except that the second metal layer is formed only on one surface. can be implemented in the same way.

Next, a seed layer and a first metal layer are formed on the other surface of the plastic film by dry plating (seed layer/first metal layer forming step). The method for producing the seed layer and the first metal layer at this time is the already explained seed layer forming step and the first metal layer forming step in the above-described one structural example of the method for producing the double-sided plated laminate, and the other step. It can be carried out in the same manner except that the seed layer and the first metal layer are formed only on the surface. The seed layer and the first metal layer can be formed continuously in one vacuum chamber as described above, but they can also be formed separately.

Then, a second metal layer is formed by wet plating on the first metal layer formed on the other surface of the plastic film (second metal layer second forming step). The method for producing the second metal layer differs from the second metal layer forming step in one configuration example of the above-described method for producing a double-sided plated laminate, in that the second metal layer is formed only on the other surface. It can be carried out in the same manner except for

As described above, when the second metal layer is formed, if the seed layer and the first metal layer are arranged on both sides of the plastic film, the moisture absorption speed of the plastic film slows down. If not implemented, the amount of water contained in the plastic film does not reach or near saturation during the formation of the second metal layer.

Then, the dimension of the plastic film is fixed by forming the second metal layer. Therefore, when the seed layer, the first metal layer, and the second metal layer are partially removed by etching or the like in order to form wiring or the like, and the surface of the plastic film is exposed, moisture absorption progresses from the exposed portion. However, a large dimensional change rate occurred.

On the other hand, when forming the second metal layer, the seed layer and the first metal layer are provided only on one surface of the plastic film, and the plastic film is exposed on the other surface. When forming the second metal layer, moisture absorption proceeds rapidly from the exposed surface of the plastic film. At the same time, the surface on which the seed layer and the first metal layer are formed also absorbs moisture, although the moisture absorption rate is slow.

Therefore, when the seed layer and the first metal layer are provided only on one side of the plastic film, unlike the case where the seed layer and the first metal layer are provided on both sides, wet process When forming the second metal layer by plating, the plastic film can absorb moisture to a saturated state. That is, when forming the second metal layer by the wet plating method, the plastic film can be in a state of maximum expansion.

When the plastic film expands to its maximum, the dimensions of the plastic film are fixed by laminating a second metal layer on one side of the plastic film by wet plating. In order to arrange the second metal layer on one side of the plastic film and fix the dimensions of the plastic film, the thickness of the second metal layer is preferably 0.3 μm or more.

As described above, the dimensions of the plastic film are fixed by forming a second metal layer on one side of the plastic film while the plastic film is in its fully expanded state. Therefore, even when the plastic film is dried to form a seed layer and a first metal layer on the other surface of the plastic film, the dimensions of the plastic film are fixed in the maximum expanded state. Further, for the double-sided plated laminate obtained by further forming the second metal layer on the other surface, even if the plastic film is exposed by etching the metal laminate and the exposed plastic film absorbs moisture, The dimensional change rate can be sufficiently suppressed.

Other configuration examples of the method for manufacturing a double-sided plated laminate according to the present embodiment may also include further optional steps.

For example, on one side of the plastic film supplied to the second metal layer first formation step, the seed layer and the first metal layer are directly arranged in that order to produce a precursor. can also

A plastic film preparation process for preparing a plastic film.
A seed layer forming step of forming a seed layer on one surface of the plastic film.

a first metal layer forming step of forming a first metal layer on the seed layer;

Note that the plastic film preparation step can be configured in the same manner as the plastic film preparation step described in the one configuration example of the manufacturing method of the double-sided plated laminate described above, so description thereof will be omitted.

In addition, with regard to the seed layer forming step and the first metal layer forming step, the seed layer forming step, the first metal layer forming step, and the plastic film described in the one structural example of the manufacturing method of the double-sided plated laminate are performed. Since the configuration can be the same except that the seed layer and the first metal layer are formed only on one surface of , the description is omitted.

According to the method for manufacturing a double-sided plated laminate of the present embodiment described above, the metal laminate disposed on the surface of the plastic film is etched to form wiring and the like, and a part of the plastic film is exposed. Even in this case, a double-sided plated laminate with suppressed dimensional change can be obtained. In addition, a double-sided plated laminate can be obtained in which wiring or the like is formed and the dimensional change is suppressed even when the plastic film is partially exposed and heated.

Therefore, the double-sided plated laminate obtained by the method for producing a double-sided plated laminate according to the present embodiment can be suitably used in various applications that particularly require suppression of dimensional changes such as wiring boards for high-density mounting. . More specifically, for example, the double-sided plated laminate obtained by the method for producing a double-sided plated laminate of the present embodiment is used as a material for a wiring board that joins electronic components, electrically connects them, and mechanically fixes them. Very useful.

A wiring board can also be produced using the double-sided plated laminate of this embodiment or the double-sided plated laminate obtained by the method for producing a double-sided plated laminate of this embodiment. For this reason, for example, a method of manufacturing a wiring board can be provided that includes a wiring forming step of forming wiring on the double-sided plated laminate of the present embodiment.

The wiring of the wiring board can be formed by, for example, a subtractive method or a semi-additive method.

The subtractive method is a method of chemically etching and removing unnecessary portions not included in the wiring pattern from a metal laminate including a seed layer, a first metal layer, and a second metal layer.

A semi-additive method is a method of selectively growing a plating film to form a circuit.

Taking the case of forming wiring by the subtractive method as an example, the wiring forming process can have the following steps.

A resist placement step of providing a resist having a shape corresponding to the wiring pattern to be formed on the second metal layer.

An etching step in which an etchant is supplied from the upper surface of the resist and chemical etching is performed to remove unnecessary portions of the metal laminate.

A cleaning step for cleaning the double-sided plated laminate to remove remaining etchant and the like.

Through the above steps, a wiring board having desired wiring can be formed.

Moreover, when forming wiring by a semi-additive method, the following processes can be further included.

After forming the first metal layer and before forming the second metal layer, a resist arrangement step of providing a resist having a shape corresponding to the wiring pattern to be formed on the first metal layer.
A resist removing step of removing the resist after forming the second metal layer.
An etching step to remove the seed layer and the first metal layer exposed by removing the resist.
A cleaning step for cleaning the double-sided plated laminate in order to remove remaining etchant and the like.

In the case of forming wiring by a semi-additive method, when forming a double-sided plating layer by one configuration example of the above-described method for manufacturing a double-sided plating layer, the above resist is applied before the above-described second metal layer forming step. A placement step can be performed. In particular, it is preferable to perform the resist placement step after the moisture absorption step.

Then, after the second metal layer forming process, the resist removing process and the etching process can be performed.

Further, when wiring is formed by a semi-additive method and a double-sided plated layer is formed by another configuration example of the above-described double-sided plated layer manufacturing method, the above-described second metal layer first formation step, and before the second metal layer second forming step, the resist disposing step can be performed.

Then, the resist removing step and the etching step can be performed after the second metal layer first forming step and the second metal layer second forming step, respectively. Also, the resist removal step and the etching step may be collectively performed after the second metal layer second formation step.

According to the method for manufacturing a wiring board described above, since the above-described double-sided plated laminate is used, a wiring board with high dimensional stability can be obtained. In addition, it is possible to obtain a wiring board having excellent thermal dimensional stability, which can sufficiently suppress dimensional change even when heated up to about 150°C. For this reason, it can be suitably used, for example, as a wiring board that requires high-density mounting.

Although specific examples and comparative examples will be given below, the present invention is not limited to these examples.

Here, a method for evaluating the obtained double-sided plated laminate will be described first.

The obtained double-sided plated laminate was measured for dimensional change according to IPC-TM-650, 2.2.4, Method B and Method C to evaluate dimensional stability.

In the index of dimensional change rate, shrinkage is indicated by a negative value and expansion is indicated by a positive value.

The dimensional change rate when etching the metal laminate was measured according to IPC-TM-650, 2.2.4, Method B. Furthermore, the dimensional change rate after heat treatment at 150° C. for 30 minutes was measured according to IPC-TM-650, 2.2.4, Method C.

The manufacturing conditions for the double-sided plated laminates in each example and comparative example will be described below.
[Example 1]
Kapton 150EN-C (manufactured by DuPont-Toray Co., Ltd.), which is a polyimide film having a width of 0.5 m and a length of 3000 m, was prepared as a plastic film (plastic film preparation step). The Kapton 150EN-C used had a thickness of 37.5 μm and a water absorption rate (saturated water absorption rate) of 1.7%. there is

The water absorption rate is calculated using the water absorption amount (saturated water absorption amount) measured when immersed in water until saturated by the A method specified in JIS K 7209 (2000). It means water absorption (saturated water absorption). Hereinafter, water absorption has the same meaning.

Next, Ni-20% Cr alloy layers with a thickness of 8 nm were formed as seed layers on both surfaces of the plastic film by a sputtering method (seed layer forming step). The Ni-20% Cr alloy means a Ni--Cr alloy composed of 20% by mass of Cr and the balance, that is, 80% by mass of Ni.

A copper layer having a thickness of 0.1 μm was formed as a first metal layer on the seed layers formed on both sides of the plastic film (first metal layer forming step).

The seed layer forming process and the first metal layer forming process were continuously performed using the film forming apparatus 30 shown in FIG. At the time of film formation, the inside of the vacuum chamber 31 is once evacuated to 1×10 ⁻⁴ Pa or less, and then argon gas is introduced to set the pressure inside the vacuum chamber 31 to 0.3 Pa. Then, one surface of the plastic film is A seed layer and a first metal layer were successively deposited on top. Next, after rewinding, a seed layer and a first metal layer were successively formed on the other surface in the same manner. Since the configuration of the film forming apparatus 30 has already been described, the description thereof is omitted.

The seed layer and the first metal layer formed on both sides of the plastic film were rewound and transported at a speed of 0.5 m/min in an atmosphere with a humidity of 65% and a temperature of 23°C (moisture absorption process).

By performing the moisture absorption step, it was possible to contain water up to 70% of the water absorption rate (saturated water absorption rate) of the plastic film at room temperature (23.0° C.±2.0° C.). In addition, Table 1 shows the above values as a ratio of the amount of water contained in the plastic film after the moisture absorption process to the saturated water absorption rate. The ratio of the amount of water contained in the plastic film after the moisture absorption process to the saturated water absorption rate was calculated from the weight change of the plastic film.

Then, a copper layer having a thickness of 8 μm was simultaneously formed on both sides of the plastic film as a second metal layer by electroplating. The second metal layer was formed using a continuous electroplating apparatus having the same configuration as the continuous electroplating apparatus 20 shown in FIG. When forming the second metal layer, the initial value of the current density is 0.05 A/dm ² , then it is gradually increased by increments of 0.04 A/dm ² , and finally increased to 2 A/dm ² . rice field. A copper sulfate plating solution was used as the plating solution.

The obtained double-sided laminate was evaluated for dimensional stability. Table 1 shows the results.
[Example 2]
Regarding the moisture absorption step, the double-sided plated laminate precursor, which is a plastic film in which the seed layer and the first metal layer are arranged in that order on both sides, is wound on a roll without rewinding and conveying, and the humidity is 65. %, and a double-sided plated laminate was obtained in the same manner as in Example 1, except that the temperature was allowed to stand in an atmosphere of 23° C. for 72 hours.

Table 1 shows the evaluation results.
[Example 3]
In the moisture absorption step, while the double-sided plated laminate precursor, which is a plastic film having a seed layer and a first metal layer arranged in that order on both sides, is wound into a roll, water having a temperature of 23 ° C. is added to the moisture absorption water tank. A double-sided plated laminate was obtained in the same manner as in Example 1, except that it was immersed in and held for 72 hours.

The humidity around the water tank was 50%.

Table 1 shows the evaluation results.
[Example 4]
As a plastic film, the same Kapton 150EN-C (manufactured by DuPont-Toray Co., Ltd.) as in Example 1 was prepared (plastic film preparation step).

Next, a Ni-20% Cr alloy layer having a thickness of 8 nm was formed as a seed layer on one surface of the plastic film by a sputtering method (seed layer forming step).

A copper layer having a thickness of 0.1 μm was formed as a first metal layer on the seed layer formed on one surface of the plastic film (first metal layer forming step).

The seed layer forming process and the first metal layer forming process were continuously performed using the film forming apparatus 30 shown in FIG. At the time of film formation, the inside of the vacuum chamber 31 is once evacuated to 1×10 ⁻⁴ Pa or less, and then argon gas is introduced to set the pressure inside the vacuum chamber to 0.3 Pa. Then, one surface of the plastic film is A seed layer and a first metal layer were successively deposited on top. Since the configuration of the film forming apparatus 30 has already been described, the description thereof is omitted.

A copper layer with a thickness of 8 μm was formed as a second metal layer by electroplating on the first metal layer formed on one surface of the plastic film via a seed layer (first formation of the second metal layer). process). The second metal layer was formed using a continuous electroplating apparatus having the same configuration as the continuous electroplating apparatus 20 shown in FIG. When forming the second metal layer, the current density is set to an initial value of 0.05 A/ ^dm2 , then gradually increased in increments of 0.04 A/ ^dm2 , and finally increased to ² A/dm2. rice field. A copper sulfate plating solution was used as the plating solution.

Then, on the other surface of the plastic film, a seed layer and a first metal layer were formed in that order from the plastic film side by a sputtering method (seed layer/first metal layer forming step).

In addition, the seed layer and the first metal layer were continuously formed under the same conditions as in the case of forming on one surface of the plastic film.

Next, a second metal layer was formed on the first metal layer of the seed layer formed on the other surface of the plastic film and the first metal layer (second metal layer second forming step).

In addition, the second metal layer was formed under the same conditions as in the case of forming it on one surface of the plastic film.

The obtained double-sided laminate was evaluated for dimensional stability. Table 1 shows the results.
[Example 5]
Same as Example 1 except that the plastic film was changed to Upilex 35SGA V1 (hereinafter simply referred to as "Upilex V1") (manufactured by Ube Industries, Ltd.), which is a polyimide film having a width of 0.5 m and a length of 3000 m. to obtain a double-sided plated laminate. The Upilex V1 used has a thickness of 34 μm and a water absorption rate (saturated water absorption rate) of 1.2%, and the same plastic film is used in Examples 6 to 8 below.

Table 1 shows the evaluation results.
[Example 6]
A double-sided plated laminate was obtained in the same manner as in Example 2, except that the plastic film was changed to Upilex V1 (manufactured by Ube Industries, Ltd.).

Table 1 shows the evaluation results.
[Example 7]
A double-sided plated laminate was obtained in the same manner as in Example 3, except that the plastic film was changed to Upilex V1 (manufactured by Ube Industries, Ltd.).

Table 1 shows the evaluation results.
[Example 8]
A double-sided plated laminate was obtained in the same manner as in Example 4, except that the plastic film was changed to Upilex V1 (manufactured by Ube Industries, Ltd.).

Table 1 shows the evaluation results.
[Comparative Example 1]
The procedure was the same as in Example 1, except that after performing the first metal layer forming step, the second metal layer forming step was performed without performing the moisture absorption step after being left in the air atmosphere (humidity 50%) for 6 hours. to obtain a double-sided plated laminate. In addition, the water content of the double-sided plated laminate precursor, which is a plastic film in which the seed layer and the first metal layer are arranged in that order on both sides, subjected to the second metal layer forming step, the water content of the plastic film, It was confirmed that the ratio to the water absorption rate (saturated water absorption rate) at room temperature was less than 70%.

Table 1 shows the evaluation results.
[Comparative Example 2]
Regarding the moisture absorption step, the plastic film having the seed layer and the first metal layer formed on both sides was wound on a roll without rewinding and conveying, and placed in an atmosphere with a humidity of 50% and a temperature of 23°C for 72 hours. A double-sided plated laminate was obtained in the same manner as in Example 1, except that it was left to stand.

Table 1 shows the evaluation results.

表１に示した結果から、実施例１～実施例８においては、ＩＰＣ－ＴＭ－６５０、２．２.４、Ｍｅｔｈｏｄ Ｂ及びＣの評価結果が±０．０５％以内になっていることが確認できた。一方比較例１、２では、上記評価結果について±０．０５％を超える場合があることを確認できた。

From the results shown in Table 1, in Examples 1 to 8, the evaluation results of IPC-TM-650, 2.2.4, Methods B and C are within ±0.05%. It could be confirmed. On the other hand, in Comparative Examples 1 and 2, it was confirmed that the above evaluation results sometimes exceeded ±0.05%.

In Examples 1 to 3 and Examples 5 to 7, the double-sided plated laminate precursor, which is a plastic film having a seed layer and a first metal layer arranged in that order on both sides, was subjected to a moisture absorption step, and The water absorption rate (saturated water absorption rate) of the plastic film is 70% or more. Therefore, the second metal layer is formed in a state in which the plastic film absorbs moisture sufficiently and expands to the maximum, and the dimension is fixed, so that the metal laminate of the seed layer, the first metal layer, and the second metal layer is formed. is partly etched, exposing the plastic film and absorbing moisture, the dimensional change hardly occurs.

In Examples 4 and 8, the seed layer, the first metal layer, and the second metal layer were first formed on one surface of the plastic film, and the plastic film was formed when the second metal layer was formed. A second metal layer is formed when the film is sufficiently hygroscopic and expanded to the maximum, and the dimensions are fixed. Therefore, even when dried to form the seed layer and the first metal layer on the other surface of the plastic film, the dimensions of the plastic film are fixed in the maximum expanded state. Further, for the double-sided plated laminate obtained by further forming the second metal layer on the other surface, even if the plastic film is exposed by etching the metal laminate and the exposed plastic film absorbs moisture, It is considered that the dimensional change rate was sufficiently suppressed.

On the other hand, in Comparative Example 1, the moisture absorption step was not performed. Also, in Comparative Example 2, a moisture absorption step is performed, but the degree of moisture absorption is not sufficient.

For this reason, when the second metal layer is formed, the plastic film is not sufficiently moisture-absorbed, so part of the metal laminate is etched, and the plastic film is exposed to absorb moisture, resulting in a large dimensional change rate. It is considered to have become

10 double-sided plated laminate 11 plastic films 12A, 12B seed layers 13A, 13B first metal layers 14A, 14B second metal layers

Claims (5)

a plastic film;
a seed layer disposed directly on both sides of the plastic film;
a first metal layer disposed on the seed layer;
A double-sided plated laminate having a second metal layer disposed on the first metal layer,
The water absorption rate of the plastic film at 23.0° C.±2.0° C. is 70% or more and less than 100%,
The dimensional change rate of MD and TD according to IPC-TM-650, 2.2.4, Method B is within ±0.05%,
IPC-TM-650, 2.2.4, a double-sided plated laminate whose dimensional change rate in MD and TD according to Method C is within ±0.05%. 2. The double-sided plated laminate according to claim 1, wherein said plastic film is a polyimide film. 3. The double-sided plated laminate according to claim 1, wherein the seed layer is a layer made of Ni--Cr alloy. The double-sided plated laminate according to any one of claims 1 to 3, wherein the first metal layer and the second metal layer are layers made of copper. The double-sided plated laminate according to any one of claims 1 to 4, wherein the sum of the thickness of the first metal layer and the thickness of the second metal layer is 0.1 µm or more and 20 µm or less.

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