JP2023022645A - Surface-treated copper material, copper-clad laminate sheet, method for manufacturing surface-treated copper material and method for manufacturing copper-clad laminate sheet - Google Patents

Abstract

To improve retention property of adhesion force between a surface of a surface-treated copper material and a resin part joined to the surface after exposed to a high-temperature environment for a long time.SOLUTION: A surface-treated copper material includes an oxidized surface including a cuprous oxide and a copper oxide. In the oxidized surface, the total of thickness (T1) of the cuprous oxide and thickness (T2) of the copper oxide is 1 nm or more and 40 nm or less which is determined by continuous electrochemical reduction analysis and a ratio (T2/T1) of the thickness (T2) of the copper oxide to the thickness (T1) of the cuprous oxide is 1 or more and 9 or less.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a surface-treated copper material, a copper-clad laminate, a method for producing a surface-treated copper material, and a method for producing a copper-clad laminate.

A copper-clad laminate in which an insulating layer and a copper layer are laminated is used as a material for manufacturing a flexible printed wiring board, for example. Such a copper-clad laminate is manufactured, for example, by laminating a copper foil and a resin sheet forming an insulating layer.

In Patent Documents 1 and 2, a copper layer and an insulating layer in a copper-clad laminate are formed by roughening the surface of the copper foil used in the production of the copper-clad laminate through oxidation-reduction treatment. A technique for increasing the peel strength between the resin layer as a is disclosed. In Patent Document 1, the thickness of copper oxide determined by continuous electrochemical reduction analysis is 1 nm or more and 20 nm or less, and the thickness of cuprous oxide is 15 nm or more and 70 nm or less. A method for manufacturing a copper clad laminate is disclosed. In Patent Document 2, the thickness of cuprous oxide determined by continuous electrochemical reduction analysis is 71 nm or more and 300 nm or less, and the thickness of copper oxide is 0 nm or more and 20 nm or less. A method for manufacturing a copper clad laminate is disclosed.

Japanese Patent No. 6178035 JP 2019-218602 A

In recent years, with the utilization of IoT (Internet of Things), electronic devices such as sensors tend to be used in various environments. For example, millimeter waves used in sensors, etc. are highly stable against light, weather, and environment. In this way, recent electronic devices are sometimes used in harsher environments, and along with this, there is a demand for improved environmental resistance performance of the electronic devices.

For example, in a flexible printed wiring board mounted on an electronic device used in a harsh environment, the adhesive strength between the copper layer and the resin layer is maintained even after being exposed to a high-temperature environment for a long time. is required. The copper-clad laminates produced by the methods described in Patent Documents 1 and 2 have room for improvement in terms of retention of adhesion after being exposed to high-temperature environments for a long period of time.

The surface-treated copper material that solves the above problems is a surface-treated copper material having an oxidized surface containing cuprous oxide and copper oxide, wherein the oxidized surface has a thickness of cuprous oxide determined by continuous electrochemical reduction analysis The total thickness (T1) and copper oxide thickness (T2) is 1 nm or more and 40 nm or less, and the ratio (T2/T1) of the copper oxide thickness (T2) to the cuprous oxide thickness (T1) is 1 9 or less.

In the surface-treated copper material, the thickness (T1) of cuprous oxide on the oxidized surface is preferably 0.1 nm or more and 20 nm or less.
In the surface-treated copper material, the thickness (T2) of copper oxide on the oxidized surface is preferably 0.9 nm or more and 36 nm or less.

A copper-clad laminate that solves the above problems includes a copper layer composed of the surface-treated copper material, and an insulating resin layer laminated on the oxidized surface of the copper layer.
In the above copper-clad laminate, the resin forming the insulating resin layer preferably contains a thermoplastic resin.

In the above copper-clad laminate, the thermoplastic resin is polyimide, liquid crystal polymer, polyether ether ketone, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, polytetrafluoroethylene. It is preferably at least one selected from.

A method for producing a surface-treated copper material that solves the above problems has a surface treatment step of forming an oxidized surface containing cuprous oxide and copper oxide on the surface of the copper material, and in the surface treatment step, continuous electrochemical reduction The sum of the thickness of cuprous oxide (T1) and the thickness of copper oxide (T2) determined by analysis is 1 nm or more and 40 nm or less, and the thickness of copper oxide (T2) relative to the thickness of cuprous oxide (T1) ), the surface of the copper material is oxidized so that the ratio (T2/T1) of 1 or more and 9 or less.

A method for producing a copper clad laminate that solves the above problems is a method for producing a copper clad laminate comprising a copper layer and an insulating resin layer laminated on the surface of the copper layer, wherein the surface-treated copper material is A lamination step of laminating and bonding an insulating resin to the oxidized surface is provided.

ADVANTAGE OF THE INVENTION According to this invention, the retention of the adhesive force between the surface of the surface-treated copper material and the resin portion bonded to the surface is improved after being exposed to a high-temperature environment for a long time.

An embodiment of the present invention will be described below.
<Surface treatment copper material>
The surface-treated copper material of this embodiment is a copper material having a specific oxidized surface.

The form of the surface-treated copper material is not particularly limited. Examples of the form of the surface-treated copper material include foil and plate. Examples of the foil-shaped surface-treated copper material include rolled copper foil and electrolytic copper foil. The thickness of the surface-treated copper material in the form of foil or plate can be appropriately set according to the application of the surface-treated copper material. For example, when used for a flexible printed circuit board, the thickness of the surface-treated copper material is, for example, 2 μm or more and 105 μm or less, preferably 2 μm or more and 70 μm or less. When used for semiconductor manufacturing equipment, thermoelectric conversion members, etc., the thickness of the surface-treated copper material is, for example, 100 μm or more and 1000 μm or less, preferably 300 μm or more and 700 μm or less.

The oxidized surface of the surface-treated copper material may be only one surface of the surface-treated copper material, or may be two or more surfaces. For example, when the surface-treated copper material is foil-shaped or plate-shaped, one side of the surface-treated copper material may be an oxidized surface, or both sides of the surface-treated copper material may be oxidized surfaces.

The oxidized surface has specific ranges for the first and second parameters based on the thickness of the cuprous oxide (T1) and the thickness of the copper oxide (T2), respectively, determined by continuous electrochemical reduction analysis (SERA). It is the surface.

The first parameter is the sum of the cuprous oxide thickness (T1) and the copper oxide thickness (T2). The first parameter is 1 nm or more and 40 nm or less. Also, the first parameter is preferably 1.2 nm or more, more preferably 1.5 nm or more. The first parameter is preferably 35 nm or less, more preferably 20 nm or less.

The second parameter is the ratio (T2/T1) of the cuprous oxide thickness (T2) to the cuprous oxide thickness (T1). The second parameter is 1 or more and 9 or less. Also, the second parameter is preferably 1.2 (55/45) or more, more preferably 1.5 (60/40) or more, and even more preferably 3 or more. The second parameter is preferably 8.1 (89/11) or less, more preferably 7.3 (88/12) or less, and more preferably 6 or less. Among these, the second parameter is particularly preferably 3 or more and 6 or less.

The thickness (T1) of cuprous oxide is, for example, 0.1 nm or more, preferably 0.2 nm or more, and more preferably 0.3 nm or more. The thickness (T1) of cuprous oxide is, for example, 20 nm or less, preferably 15 nm or less, and more preferably 5 nm or less.

The thickness (T2) of copper oxide is, for example, 0.9 nm or more, preferably 1.0 nm or more, and more preferably 1.2 nm or more. The thickness (T2) of copper oxide is, for example, 36 nm or less, preferably 20 nm or less, and more preferably 15 nm or less.

Continuous electrochemical reduction analysis to determine cuprous oxide thickness (T1) and copper oxide thickness (T2) can be performed using a commercially available measurement device such as the ECI TECHNOLOGY QC-100. can be done. An example method for determining cuprous oxide thickness (T1) and copper oxide thickness (T2) based on continuous electrochemical reduction analysis is described below.

A circular area with a diameter of 0.16 cm on the surface-treated copper material to be measured is isolated by a ring gasket, injected with electrolyte and saturated with nitrogen. The electrolytic solution is, for example, a pH 8.4 borate buffer prepared with pure water so as to contain 6.18 g/L of boric acid and 9.55 g/L of sodium tetraborate decahydrate. A current density of 150 μA/cm ² was applied to the above region, and the reduction reaction time (seconds) appearing at −0.35 to −0.60 V (Cu ₂ O) and −0.60 to −0.85 V (CuO) was measured. measure. Based on the measured reduction reaction times, the thickness of Cu ₂ O (T1) and the thickness of CuO (T2) are calculated using the following equations.

T1 (nm) = 0.001236 x current density (μA/cm ² ) x reduction time (seconds)
T2 (nm) = 0.000639 x current density (μA/cm ² ) x reduction time (seconds)
The oxidized surface of the surface-treated copper material may have an antirust layer. As the antirust layer, one that is generally applied to a copper material can be used. The rust preventive layer is preferably an organic rust preventive layer, and more preferably an organic rust preventive layer containing at least one of a triazole-based rust preventive agent and a silane coupling-based rust preventive agent. Examples of triazole-based rust inhibitors and silane-coupling-based rust inhibitors include the compounds described in Patent Document 2.

<Method for producing surface-treated copper material>
A method for producing a surface-treated copper material has a surface treatment step of forming the above-described oxidized surface on the surface of the copper material. Examples of the surface treatment performed in the surface treatment step include heat treatment for heating the surface of the copper material in an oxidizing atmosphere, and oxidation-reduction treatment for sequentially performing oxidation treatment and reduction treatment on the surface of the copper material. From the viewpoint of reducing the environmental load caused by the waste liquid, the surface treatment step is preferably a heat treatment that does not use various treatment liquids that require post-treatment.

The heat treatment is a treatment of heating the surface of the copper material in an oxidizing atmosphere using a heating device. As the heating device, for example, a known heating device such as a far-infrared heating furnace and a blowing furnace can be used. The heating device preferably has a mechanism for making the temperature in the furnace uniform.

The heating temperature in the heat treatment is, for example, 150° C. or higher and 200° C. or lower.
The heating time in the heat treatment is, for example, 120 seconds or more and 1200 seconds or less.
Examples of the oxidizing atmosphere in the heat treatment include air, oxygen, ozone, and carbon dioxide.

When heat treatment is used as the surface treatment step, for example, the first parameter and the second parameter can be adjusted by adjusting the heating temperature, heating time, and composition of the oxidizing atmosphere.

The formation process of the oxidized surface by heat treatment is considered as follows. As the first stage, which is the initial stage of the heat treatment, a reaction proceeds in which cuprous oxide present on the surface of the copper material is oxidized to copper oxide. Then, when further heated, as a second step, a reaction in which the inner copper is oxidized to cuprous oxide and a reaction in which one or both of the inner copper and cuprous oxide are oxidized to copper oxide are performed in parallel. proceed.

Therefore, the first parameter, which is the sum of the cuprous oxide thickness (T1) and the copper oxide thickness (T2), increases as the progress of the second stage reaction increases. Therefore, when the first parameter is increased, the degree of progress of the reaction in the second stage may be increased, and when the first parameter is decreased, the degree of progress of the reaction in the second stage is decreased, or in the middle of the first stage. The heat treatment should be terminated with .

Also, in the second stage reaction, cuprous oxide is oxidized to copper oxide, while copper oxide is accumulated as it is, so the thickness of cuprous oxide (T2) with respect to the thickness of cuprous oxide (T1) The second parameter, which is the ratio of (T2/T1), increases as the total amount of copper oxide increases. Therefore, when increasing the second parameter, the degree of progress of the reaction in the second stage should be increased, and when decreasing the second parameter, the degree of progress of the reaction in the second stage should be decreased. In the case of ending the heat treatment in the middle of the first step, if the second parameter is increased, the degree of progress of the reaction in the first step should be increased, and if the second parameter is decreased, the first step The degree of progress of the reaction of can be reduced.

The degree of progress of the reaction in the second stage is increased by any one or more of increasing the heating temperature, lengthening the heating time, and increasing the oxygen-rich degree of the oxidizing atmosphere. change to If the heat treatment is terminated in the middle of the first stage, the heating time is shortened. The degree of progress of the first stage is increased by further performing any one or more of increasing the heating temperature and increasing the oxygen-rich degree of the oxidizing atmosphere under the condition that the heating time is shortened. change to Using these tendencies, the heat treatment is performed so that the first parameter and the second parameter are within the specific ranges described above.

In the oxidation-reduction treatment, first, a specific surface of the copper material is subjected to an oxidation treatment to obtain an oxidized copper material having a copper compound containing copper oxide formed on the specific surface. Then, the specific surface of the oxidized copper material is subjected to a reduction treatment to convert a part of the copper oxide contained in the copper compound on the specific surface to cuprous oxide, so that copper containing cuprous oxide and copper oxide A surface-treated copper material having a compound formed on a specific surface is obtained. The oxidation treatment and reduction treatment are not particularly limited, and a conventionally known method such as a wet method using an oxidation treatment liquid and a reduction treatment liquid disclosed in Patent Document 2 can be applied.

When oxidation-reduction treatment is used as the surface treatment step, the above first parameter and second parameter can be adjusted, for example, by adjusting the times of oxidation treatment and reduction treatment. For example, increasing the oxidation treatment time tends to increase the first parameter, which is the sum of the cuprous oxide thickness (T1) and the copper oxide thickness (T2). In addition, when the treatment time of the reduction treatment is lengthened, the second parameter, which is the ratio (T2/T1) of the thickness (T2) of cuprous oxide to the thickness (T1) of cuprous oxide, tends to decrease. Utilizing these tendencies, the oxidation-reduction treatment is performed so that the first parameter and the second parameter are within the specific ranges described above.

Moreover, the surface treatment process may be performed continuously on the copper material continuously supplied from a film roll or the like, or may be performed batchwise for each predetermined unit.
<Copper clad laminate>
A copper-clad laminate is a laminate comprising a copper layer and an insulating resin layer laminated on the copper layer.

The copper layer is a layer composed of a surface-treated copper material, and at least one surface is the oxidized surface described above. The thickness of the copper layer is the same as the thickness of the surface-treated copper material.
The insulating resin layer is a layer laminated and bonded to the surface of the copper layer composed of the oxidized surface of the surface-treated copper material. The resin constituting the insulating resin layer is not particularly limited, and known resins used for substrates of flexible printed wiring boards, semiconductor manufacturing equipment, and thermoelectric conversion members can be used.

Examples of the resin constituting the insulating resin layer include polyimide (PI), liquid crystal polymer (LCP), polyetheretherketone (PEEK), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene- Hexafluoropropylene copolymer (FEP), polytetrafluoroethylene (PTFE), tetrafluoroethylene-ethylene copolymer (ETFE), polyamideimide (PAI), cycloolefin polymer (COP), polyphenylene sulfide (PPS), Syndi Occult polystyrene (SPS) can be mentioned. The resin constituting the insulating resin layer may be of only one type, or may be a combination of two or more types.

Also, the insulating resin layer preferably contains a thermoplastic resin. In this case, when the copper layer and the insulating resin layer are joined together, the thermoplastic resin contained in the insulating resin layer softens and enters into the fine irregularities formed on the oxidized surface of the copper layer. The adhesion between the copper layer and the insulating resin layer is improved based on the anchor effect. In this case, among the above resins, polyimide (PI), liquid crystal polymer (LCP), polyether ether ketone (PEEK), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer It is particularly preferable to use at least one thermoplastic resin selected from polymers (FEP) and polytetrafluoroethylene (PTFE).

The thickness of the insulating resin layer is not particularly limited, and can be appropriately set according to the use of the copper-clad laminate. The thickness of the insulating resin layer is, for example, 1 μm or more and 1000 μm or less, preferably 5 μm or more and 200 μm or less, and more preferably 12.5 μm or more and 100 μm or less.

The insulating resin layer may have a single layer structure, or may have a laminated structure in which a plurality of resin layers are laminated.
The insulating resin layer may be provided only on one surface of the copper layer, or may be provided on both surfaces of the copper layer. When insulating resin layers are provided on both surfaces of the copper layer, both surfaces of the copper layer are preferably oxidized surfaces.

<Method for producing copper-clad laminate>
Next, a method for manufacturing a copper-clad laminate will be described.
A method of manufacturing a copper-clad laminate includes a lamination step of laminating and bonding an insulating resin to the oxidized surface of the surface-treated copper material. As the lamination process, for example, a process of thermocompression bonding a resin film made of an insulating thermoplastic resin, a process of applying a molten insulating resin to the oxidized surface of the surface-treated copper material and solidifying it, a process of solidifying the surface-treated copper material a process of adhering an insulating resin film to the oxidized surface of the substrate via a resin adhesive. As an example, the thermocompression bonding process will be specifically described below.

In the thermocompression bonding, a resin film is superimposed on the oxidized surface of the surface-treated copper material, and the surface-treated copper material and the resin film are heated and pressurized with a predetermined pressure using a heating and pressurizing device. The thermocompression bonding may be performed continuously on the surface-treated copper material and the resin film which are continuously supplied from a film roll or the like, or may be performed batchwise for each predetermined unit.

The heating temperature in the thermocompression bonding process is, for example, 300° C. or higher and 400° C. or lower. The heating time in the thermocompression bonding process is, for example, 1 minute or more and 30 minutes or less. In the thermocompression bonding process, the pressure applied to the surface-treated copper material and the resin film is, for example, 2 MPa or more and 12 MPa or less.

The heating and pressurizing device is not particularly limited as long as it can satisfy the above conditions. As the heating and pressurizing device, for example, a heat press machine having a flat heating and pressurizing part, a vacuum batch press machine, a multi-stage press machine, a heating roll press machine, and a double belt press device that heats and presses between belts. is mentioned.

Next, the operation and effects of this embodiment will be described.
(1) The surface-treated copper material is used as a component of an article having a resin portion bonded to the oxidized surface of the surface-treated copper material. Examples of the article include a copper-clad laminate including a copper layer and an insulating resin layer laminated on the surface of the copper layer.

The surface-treated copper material has an oxidized surface that includes cuprous oxide and copper oxide. The oxidized surface has a total of 1 nm or more and 40 nm or less of the cuprous oxide thickness (T1) and the cuprous oxide thickness (T2) determined by continuous electrochemical reduction analysis, and the cuprous oxide thickness (T1) The ratio (T2/T1) of the thickness (T2) of the copper oxide to the copper oxide is 1 or more and 9 or less.

By setting the sum and ratio (T2/T1) of the thickness (T1) of cuprous oxide and the thickness (T2) of cuprous oxide on the oxidized surface of the surface-treated copper material to the above specific range, oxidation of the surface-treated copper material It is possible to increase the adhesion force of the joint portion of the article formed by joining the resin portion to the surface. In addition, even after the article is exposed to a high-temperature environment for a long period of time, it is possible to suppress a decrease in the adhesive strength of the joint portion and maintain the adhesive strength favorably.

(2) The ratio (T2/T1) of the thickness (T2) of cuprous oxide to the thickness (T1) of cuprous oxide is 3 or more and 6 or less. In this case, the above effect (1) can be obtained remarkably.
(3) The thickness (T1) of cuprous oxide on the oxidized surface is 0.1 nm or more and 20 nm or less. In this case, the above effect (1) can be obtained remarkably.

(4) The thickness (T2) of copper oxide on the oxidized surface is 0.9 nm or more and 36 nm or less. In this case, the above effect (1) can be obtained remarkably.
(5) The resin forming the insulating resin layer includes a thermoplastic resin.

In this case, the thermoplastic resin contained in the insulating resin layer is softened and penetrates into the fine uneven structure formed on the oxidized surface of the copper layer, so that the copper layer and the insulating resin are bonded together based on the anchor effect. Improves adhesion to layers.

(6) The thermoplastic resin constituting the insulating resin layer is polyimide, liquid crystal polymer, polyether ether ketone, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, polytetrafluoro It is at least one selected from ethylene. In this case, the above effect (5) can be obtained remarkably.

(7) A method for producing a surface-treated copper material has a surface treatment step of forming an oxidized surface containing cuprous oxide and copper oxide on the surface of the copper material. In the surface treatment step, the sum of the cuprous oxide thickness (T1) and the copper oxide thickness (T2) determined by continuous electrochemical reduction analysis is 1 nm or more and 40 nm or less, and the cuprous oxide thickness (T1 ), the surface of the copper material is heated in an oxidizing atmosphere so that the ratio (T2/T1) of the thickness (T2) of the copper oxide to ) is 1 or more and 9 or less.

According to the above configuration, the thickness of cuprous oxide and the thickness of copper oxide can be increased without using various treatment solutions that require post-treatment such as oxidation treatment solutions and reduction treatment solutions used in wet oxidation-reduction treatment. can form an oxidized surface having a specific range of sums and ratios of Therefore, it is possible to reduce the load on the environment due to the waste liquid generated in the production of the surface-treated copper material.

In addition, thick copper materials used in semiconductor manufacturing equipment and thermoelectric conversion members, for example, copper materials with a thickness of 100 μm or more are roughened by the methods disclosed in Patent Documents 1 and 2. difficult to do According to the above configuration, it is possible to form a surface having high adhesion to resin even for a thick copper material.

Further, according to the above configuration, the surface on which the rust-preventive layer is formed can be oxidized by performing the above-described heat treatment on the surface of the copper material on which the rust-preventive layer is formed. In other words, the oxidized surface can be formed after the formation of the antirust layer.

It should be noted that the above embodiment can be implemented with the following modifications. The above embodiments and the following modifications can be combined with each other within a technically consistent range.

- The application of the surface-treated copper material of the above embodiment is not limited to a copper-clad laminate obtained by laminating an insulating resin layer on the surface-treated copper material. The surface-treated copper material of the above-described embodiment can be applied to general components of an article having a resin portion bonded to the oxidized surface of the surface-treated copper material. In this case, the resin bonded to the oxidized surface of the surface-treated copper material is not limited to insulating resin.

・By continuously performing a surface treatment process for forming an oxidized surface on the surface of the copper material and a lamination process for laminating and bonding an insulating resin to the oxidized surface of the surface-treated copper material obtained by the surface treatment process. , a copper clad laminate may be produced.

- The copper-clad laminate may include layers other than the copper layer and the insulating resin layer.

Next, the embodiment will be described more specifically with reference to examples and comparative examples.
(Examples 1 to 7 and Comparative Examples 1 to 4)
The surface-treated copper materials of Examples 1 to 7 and Comparative Examples 1 to 4 were produced by putting the copper foil into an air blowing oven set at a predetermined temperature and performing heat treatment for a predetermined time. As shown in Table 1, the surface-treated copper materials of each example differed in the type and thickness of the copper foil used, as well as the temperature and time of heat treatment. As the copper foil, HCL-02Z or C1020 foil manufactured by Hitachi Metals Neomaterial was used. Comparative Example 1 is a copper foil that is not heat-treated.

(Continuous electrochemical reduction analysis)
A measurement sample cut from the surface-treated copper material of each example and each comparative example was immersed in a butyl cellosolve solution for 20 minutes, and then ultrasonically cleaned in a 2-propanol solution for 5 minutes to remove foreign matter. After that, using a measuring device (ECI TECHNOLOGY QC-100), the thickness (T1) of cuprous oxide (Cu ₂ O) and the thickness (T2) of copper oxide (CuO) contained in the oxidized surface of the test sample ) was measured by continuous electrochemical reduction analysis (SERA).

First, a circular area of 0.16 cm diameter in the test sample was isolated by a ring gasket, injected with electrolyte and saturated with nitrogen. As the electrolytic solution, a borate buffer solution of pH 8.4 prepared with pure water so as to contain 6.18 g/L of boric acid and 9.55 g/L of sodium tetraborate decahydrate was used. After that, a current density of 150 μA/cm ² was applied, and the reduction reaction time (seconds) appearing at −0.35 to −0.60 V (Cu ₂ O) and −0.60 to −0.85 V (CuO) was measured. bottom.

Based on the measured reduction reaction time, the thickness of Cu ₂ O (T1) and the thickness of CuO (T2) were calculated using the following equations. Also, the total thickness (T1+T2) and the thickness ratio (T2/T1) were calculated from the calculated thickness (T1) of Cu ₂ O and thickness (T2) of CuO. Those results are shown in Table 1.

T1 (nm) = 0.001236 x current density (μA/cm ² ) x reduction time (seconds)
T2 (nm) = 0.000639 x current density (μA/cm ² ) x reduction time (seconds)

加熱処理における温度及び時間を変更することにより、第１パラメータである厚さ合計（Ｔ１＋Ｔ２）、及び第２パラメータである厚さ比（Ｔ２／Ｔ１）がそれぞれ異なる酸化表面を有する実施例１～７及び比較例１～４の表面処理銅材が得られた。なお、比較例２は、酸化銅の厚さの値よりも亜酸化銅の厚さの値が大きいことから、特許文献１及び特許文献２の実施例欄に開示される実験例に相当する。また、得られた各例の表面処理銅材の酸化表面を目視にて観察した結果、変色及び加熱むらは確認されなかった。

By changing the temperature and time in the heat treatment, the first parameter, the total thickness (T1 + T2), and the second parameter, the thickness ratio (T2/T1), are different from each other Examples 1 to 7 having an oxidized surface And surface-treated copper materials of Comparative Examples 1 to 4 were obtained. Comparative Example 2 corresponds to the experimental example disclosed in the Examples column of Patent Documents 1 and 2, since the value of the thickness of cuprous oxide is larger than the value of the thickness of copper oxide. Moreover, as a result of visually observing the oxidized surface of the surface-treated copper material obtained in each example, no discoloration or uneven heating was observed.

(Test Examples 1 to 12)
A 25 μm-thick resin film was laminated on the oxidized surface of the surface-treated copper material of each example and each comparative example and thermocompression bonded by a batch press to obtain a copper layer made of the surface-treated copper material and a resin layer made of the resin film. Copper clad laminates of Test Examples 1 to 12 were produced. Table 2 shows the combination of the surface-treated copper material and the resin film and the type of the resin film in each test example. Details of the types of resin films and thermocompression bonding conditions shown in Table 2 are as described below.

PI-A: polyimide film (Upilex-VT manufactured by Ube Industries, Ltd.)
LCP: liquid crystal polymer film (CTZ manufactured by Kuraray Co., Ltd.)
PI-B: polyimide film (Kapton AENC manufactured by Toray DuPont Co., Ltd.)
Condition 1: maximum temperature of 330°C, pressure of 106 kg/cm ² , heating time of 30 minutes Condition 2: maximum temperature of 305°C, pressure of 106 kg/cm ² , heating time of 10 minutes (Evaluation of Adhesion)
After the production, test samples were prepared by cutting the copper-clad laminate of each test example stored at normal temperature and normal pressure into strips having a width of 10 mm. Based on "Method A" specified in JIS C6471 (90 ° direction peeling method, however, the method of peeling off the resin layer in the direction of 90 ° to the surface where the resin layer is laminated in the copper layer) The peel strength between the copper layer and the resin layer of the sample was measured. The value measured here was taken as the normal peel strength. Table 2 shows the results.

Next, the copper-clad laminate of the test example having a normal peel strength of 1.0 N / mm or more was exposed to a high temperature environment of 150 ° C. for 1000 hours. Test samples were prepared by cutting into . The peel strength between the copper layer and the resin layer of the test sample obtained from the copper-clad laminate after the exposure treatment was measured by the same method as above. Using the measured value as the peel strength after exposure to high temperature, the retention rate of peel strength before and after the exposure treatment was calculated using the following formula. Table 2 shows the results.

Retention rate (%) = (peel strength after high temperature exposure/normal peel strength) x 100

表２に示すように、試験例１～７は、厚さ合計（Ｔ１＋Ｔ２）が１ｎｍ以上４０ｎｍ以下であり、厚さ比（Ｔ２／Ｔ１）が１以上９以下である実施例１～７の表面処理銅材を用いている。試験例１～７の常態の剥離強度は、比較例１の表面処理銅材を用いた試験例８及び試験例１２と比較して高い値であった。加えて、試験例１～７の剥離強度の保持率は、６０％以上であった。試験例１～７のなかでも、厚さ比（Ｔ２／Ｔ１）が３以上６以下である実施例１～４の表面処理銅材を用いた試験例１～４は、７０％以上という高い保持率であった。また、これらの効果は、銅箔の種別及び厚さ、並びに樹脂の種別を変更した場合にも得られたことから、銅箔の種別及び厚さ、並びに樹脂の種別に依存しない効果であると考えられる。

As shown in Table 2, Test Examples 1 to 7 have a total thickness (T1+T2) of 1 nm or more and 40 nm or less, and a thickness ratio (T2/T1) of 1 or more and 9 or less. Treated copper material is used. The normal peel strengths of Test Examples 1 to 7 were higher than those of Test Examples 8 and 12 using the surface-treated copper material of Comparative Example 1. In addition, the peel strength retention rate of Test Examples 1 to 7 was 60% or more. Among Test Examples 1 to 7, Test Examples 1 to 4 using the surface-treated copper materials of Examples 1 to 4 having a thickness ratio (T2/T1) of 3 to 6 have a high retention of 70% or more. was the rate. In addition, since these effects were obtained even when the type and thickness of the copper foil and the type of resin were changed, it was concluded that the effects were independent of the type and thickness of the copper foil and the type of resin. Conceivable.

Test Examples 9 and 11 using the surface-treated copper materials of Comparative Examples 2 and 4, in which the total thickness (T1+T2) is within the above range and the thickness ratio (T2/T1) is outside the above range, were normal. Although the peel strength of was comparable to that of Test Examples 1 to 7, the peel strength retention rate was substantially zero. From this result, it is considered important to form an oxidized surface containing more copper oxide than cuprous oxide in order to maintain the peel strength even after high temperature exposure.

In addition, Test Example 10 using the surface-treated copper material of Comparative Example 3, in which both the total thickness (T1+T2) and the thickness ratio (T2/T1) are outside the above ranges, had peel strength in the normal state of Test Examples 1 to 7. , and the effect of improving the peel strength by heat treatment was not obtained. It is considered that the oxidized surface of the surface-treated copper material of Comparative Example 3 used in Test Example 10 became structurally fragile due to the excessive formation of copper oxide.

Claims (8)

A surface-treated copper material having an oxidized surface containing cuprous oxide and copper oxide,
The oxidized surface has a total of 1 nm or more and 40 nm or less of the cuprous oxide thickness (T1) and the copper oxide thickness (T2) determined by continuous electrochemical reduction analysis, and the cuprous oxide thickness (T1 ), wherein the ratio (T2/T1) of the thickness (T2) of copper oxide to ) is 1 or more and 9 or less. The surface-treated copper material according to claim 1, wherein the thickness (T1) of the cuprous oxide on the oxidized surface is 0.1 nm or more and 20 nm or less. The surface-treated copper material according to claim 1 or 2, wherein the thickness (T2) of the copper oxide on the oxidized surface is 0.9 nm or more and 36 nm or less. A copper-clad laminate comprising a copper layer composed of the surface-treated copper material according to any one of claims 1 to 3, and an insulating resin layer laminated on the oxidized surface of the copper layer. 5. The copper-clad laminate according to claim 4, wherein the resin constituting the insulating resin layer contains a thermoplastic resin. The thermoplastic resin is at least one selected from polyimide, liquid crystal polymer, polyetheretherketone, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and polytetrafluoroethylene. The copper-clad laminate according to claim 5. Having a surface treatment step of forming an oxidized surface containing cuprous oxide and copper oxide on the surface of the copper material,
In the surface treatment step, the sum of the cuprous oxide thickness (T1) and the copper oxide thickness (T2) determined by continuous electrochemical reduction analysis is 1 nm or more and 40 nm or less, and the cuprous oxide thickness ( A method for producing a surface-treated copper material, wherein the surface of the copper material is oxidized so that the ratio (T2/T1) of the thickness (T2) of the copper oxide to T1) is 1 or more and 9 or less. A method for manufacturing a copper clad laminate comprising a copper layer and an insulating resin layer laminated on the surface of the copper layer,
A method for producing a copper-clad laminate, comprising a lamination step of laminating and bonding an insulating resin to the oxidized surface of the surface-treated copper material according to any one of claims 1 to 3.