JP6060836B2 - Surface treatment method for resin film and method for producing copper clad laminate including the same - Google Patents

Description

  The present invention relates to a surface treatment method applied to a resin film before the film formation process of the resin film, and in particular, for improving adhesion before performing film formation such as sputtering while conveying a long resin film. The present invention relates to a surface treatment method applied to the long resin film.

  In a liquid crystal panel, a notebook computer, a digital camera, a mobile phone, and the like, a flexible wiring board in which a wiring pattern is formed on a heat resistant resin film is used. This flexible wiring board can be obtained by patterning a copper-clad laminate in which a copper thin film is formed on one side or both sides of a heat resistant resin film. In recent years, wiring patterns tend to be more delicate and denser, and accordingly, copper-clad laminates themselves are required to be smooth without wrinkles.

  As a method for producing a heat-resistant resin film with a metal film typified by the copper-clad laminate described above, conventionally, a method for producing a metal foil attached to a heat-resistant resin film with an adhesive (a method for producing a three-layer substrate), A metal film coated with a heat-resistant resin solution on a metal foil and dried (casting method), a vacuum film-forming method alone on a heat-resistant resin film, or a combination of a vacuum film-forming method and a wet plating method. A method (metalizing method) for producing a film by forming a film is known. Examples of the vacuum film forming method used for the metalizing method include a vacuum deposition method, a sputtering method, an ion plating method, and an ion beam sputtering method.

  Regarding the metallizing method, Patent Document 1 describes a method of forming a conductor layer by sputtering copper after sputtering a chromium layer on a polyimide insulating layer. Patent Document 2 discloses a flexible circuit in which a first metal thin film formed by sputtering using a copper-nickel alloy as a target and a second metal thin film formed by sputtering using a copper as a target are formed in this order on a polyimide film. A substrate material is disclosed.

  Film formation by these sputtering methods is generally excellent in adhesion, but it is said that the heat load applied to the heat-resistant resin film as a base material is larger than that in the vacuum evaporation method. It is also known that when a large heat load is applied to the heat resistant resin film during film formation, the film is likely to be wrinkled. Therefore, in order to prevent the generation of wrinkles, a sputtering web coater is generally used in the process of forming a heat resistant resin film with a metal film by forming a film on a heat resistant resin film such as a polyimide film by a vacuum film forming method. Is used. This apparatus includes a can roll in which a refrigerant is circulated, and a long heat-resistant resin film conveyed by roll-to-roll is wound around the outer peripheral surface of the can roll and cooled from the back side. Sputtering is performed.

  By the way, in the production process of the heat-resistant resin film with a metal film as described above, in order to further improve the adhesion between the heat-resistant resin film and the metal film, the heat-resistant resin film is previously subjected to plasma treatment or ion beam irradiation treatment. Application is known to be effective. For example, Patent Document 3 discloses not only initial adhesion but also adhesion in a high-temperature environment and a high-temperature and high-humidity environment by regulating the thickness of the modified layer on the polyimide film surface formed by plasma treatment to a predetermined value or less. The technology to improve the balance is shown. Further, in Patent Document 4, when the surface modification of polyimide is performed by a dry method, only the initial adhesion force can be obtained by suppressing the thickness of the mixed layer of polyimide and metal formed by the modification to a predetermined value or less. A technique for improving the adhesion after aging is disclosed.

Japanese Patent Laid-Open No. 2-98994 Japanese Patent No. 3447070 JP 2007-318177 A International Publication No. 2010/098236 Pamphlet

  However, in the plasma treatment, if excessive plasma treatment is performed to improve the initial peel strength, the PCT peel strength (Pressure Cooker Test 121 ° C. × 95% × 2 atm × 100), which is an index of adhesion in a high temperature and high humidity environment. The heat-resistant peel strength (150 ° C. × 168 hours), which is an index of adhesion strength in a high temperature environment, may be significantly reduced compared to (time). This reduction in heat-resistant peel strength results in the formation of a thick modified layer on the polyimide surface due to excessive plasma treatment, and the oxygen contained in the modified layer oxidizes the underlying metal layer, reducing the adhesion to the polyimide. I think that.

  The present invention has been made paying attention to such conventional problems, and in the step of forming a metal film on a resin film by sputtering, the resin film and the metal film can be formed without reducing the heat-resistant peel strength. An object of the present invention is to provide a pretreatment method capable of increasing the adhesion.

  In order to solve the above-mentioned problems, the present inventor has conducted intensive research. As a result, in a film forming apparatus that performs vacuum film formation by winding a long resin film conveyed by roll-to-roll in a vacuum chamber around the outer surface of a can roll. The present inventors have found that good results can be obtained by irradiating an ion beam after the plasma treatment before film formation to improve the adhesion between the long resin film and the base metal layer. It was.

That is, the surface treatment method of a resin film of the present invention is a surface treatment method prior to the film formation by a dry plating method on a resin film in a reduced pressure atmosphere, irradiating the flop plasma on at least one surface of the resin film to subjected to a plasma treatment is intended to remove the surface of the modified layer modified with the plasma treatment by subjecting an ion beam processing of irradiating an ion beam on the surface irradiated with the plasma, the ion beam In the processing, in the correlation between the ion beam voltage and the peel strength obtained in advance, when the ion beam voltage is lowered, the ion beam voltage is higher than the ion beam voltage when the heat-resistant peel strength starts to drop and the ion beam voltage is raised. the PCT peel strength to apply an ion beam voltage of the ion beam voltage following range when starts to decrease when Tsu It is characterized.

  According to the present invention, in addition to having a high initial peel strength, it is possible to provide a copper-clad laminate board that has both a high PCT peel strength and a high heat-resistant peel strength. It becomes possible.

It is a typical front view of the vacuum film-forming apparatus which can suitably implement one specific example of the pretreatment method concerning the present invention. It is a typical front view of the vacuum film-forming apparatus which can carry out other specific examples of the pretreatment method concerning the present invention suitably. It is a typical front view of the vacuum film-forming apparatus which can implement the pre-processing method of a comparative example. In Example 1, it is a graph which shows the relationship between the ion beam voltage and peel strength in the conveyance speed of 6 m / min. In Example 1, it is a graph which shows the relationship between the ion beam voltage and peel strength in the conveyance speed of 8 m / min.

  First, a long resin film vacuum film forming apparatus that can suitably carry out the pretreatment method of the present invention will be described with reference to FIG. 1 by taking a roll-to-roll sputtering apparatus as an example. 1 is a continuous film forming apparatus also called a sputtering web coater, and is a long heat-resistant resin film (hereinafter referred to as unrolled roll) in an unwinding chamber 210. F is first pre-treated in the plasma chamber 234 and the ion beam chamber 239, and then subjected to film formation in the film formation chamber 211, and is taken up by a take-up roll 229 in the take-up chamber 212. It has become.

  More specifically, the resin film F is unwound from the unwinding roll 214 in the unwinding chamber 210, and is measured in the tension sensor roll 215 before being sent into the heater box 216, where the heater 217, The front and back surfaces are dried by 218. The dried resin film F is sent to the plasma chamber 234 through the free roll 219.

  In the plasma chamber 234, it is guided to the first cooling roll 236 through the free roll 235, where the resin film F is wound around the outer peripheral surface of the first cooling roll 236 and cooled from the back side, and is subjected to a plasma treatment with a heat load. Is given. This plasma treatment is performed by irradiating the resin film F with plasma from a plasma generator 238 provided to face the outer peripheral surface of the first cooling roll 236. The plasma-treated resin film F is sent to the ion beam chamber 239 through a free roll 237.

  In the ion beam chamber 239, the ion beam is guided to the second cooling roll 241 through the free roll 240, and the resin film F is wound around the outer peripheral surface of the second cooling roll 241 and cooled from the back side while being subjected to heat load. Beam processing is performed. This ion beam treatment is performed by irradiating the resin film F with an ion beam from an ion beam generator 243 provided so as to face the outer peripheral surface of the second cooling roll 241. The resin film F subjected to the ion beam treatment in the ion beam chamber 239 then enters the film formation chamber 211. The plasma chamber 234 and the ion beam chamber 239 are isolated from each other, and the atmosphere gas composition and pressure can be controlled separately so that the processing atmospheres are different from each other.

  In the film forming chamber 211, the resin film F is guided to the water-cooled can roll 223 through the free roll 220, the tension sensor roll 221, and the front feed roll 222. Here, while the resin film F is wound around the outer peripheral surface of the water-cooled can roll 223 and cooled from the back surface side, a film forming process is performed by the sputtering cathodes 230, 231, 232, and 233.

  By attaching a plate-like sputtering target to the sputtering cathodes 230 to 233, for example, a metal layer made of a nickel-chromium alloy as a base metal layer and a copper thin film layer made of a copper layer as a metal layer thereon are formed. A film can be formed, thereby obtaining a copper clad laminate. In the plate-like sputtering target, nodules (foreign substance growth) may occur on the target. When this becomes a problem, a cylindrical rotary target that does not generate nodules and has high target use efficiency may be used. In addition, the composition of the base metal layer is selected according to desired characteristics such as electrical insulation and migration resistance of the copper clad laminate, and the material is Ni—Cr alloy, Inconel, Constantan, Monel, etc. Alloys can be used.

In the film formation chamber 211, for the above-described sputtering film formation, a pressure reduction to an ultimate pressure of about 10 ⁻⁴ Pa and a subsequent pressure adjustment of about 0.1 to 10 Pa by introduction of a sputtering gas are performed. A known gas such as argon is used as the sputtering gas, and a gas such as oxygen is further added according to the purpose. Therefore, various devices such as a dry pump, a turbo molecular pump, and a cryocoil (not shown) are provided. Note that there are no particular limitations on the shape or material of the vacuum chamber that forms the film formation chamber 211, as long as it can withstand such a reduced pressure state, and various types can be used. The resin film F that has been subjected to film formation is sent to the take-up chamber 212 via a rear feed roll 224, a tension sensor roll 225, and a free roll 226.

  The resin film F that has entered the take-up chamber 212 passes through the free roll 227 and the tension sensor roll 228, and is then taken up by the take-up roll 229. In FIG. 1, some free rolls and vacuum exhaust equipment for changing the transport direction of the resin film F are not shown. Further, the rotation speeds of the unwinding roll, the front feed roll, the rear feed roll, and the cooling roll are controlled by each tension sensor roll.

  A resin film with a metal thin film in which a metal layer having a predetermined film thickness is laminated by the above-described continuous series of treatments is obtained. In addition, depending on the film thickness of the target copper layer, when the copper-clad laminate is completed only with the resin film with the metal thin film, the surface of the copper thin film layer is further subjected to copper plating by wet plating, and the film thickness of the copper layer May be completed as a copper-clad laminate with increased thickness. In this wet plating method, there are a case where a metal film is formed only by an electroplating treatment, and an electroless plating treatment as a primary plating and an electrolytic plating treatment as a secondary plating are combined. In addition, various conditions of a general wet plating method can be employed for these wet plating processes.

  Next, plasma processing and ion beam processing will be examined in more detail. The plasma treatment is performed on the resin film F and its surface by introducing hydrophilic functional groups such as carboxyl groups and hydroxyl groups into the surface portion of the long resin film by appropriately adjusting the atmospheric gas composition and the like. This improves the adhesion with the metal film. For example, in the case of oxygen plasma, oxygen atoms can be added to the surface of the resin film F to introduce functional groups such as OH groups. However, if the plasma treatment is excessively performed to improve the initial peel strength (adhesion), the heat-resistant peel strength (150 ° C. × 168 hours) compared to the PCT peel strength (121 ° C. × 95% × 2 atm × 100 hours). ) Significantly decreases, and the heat-resistant peel strength and the PCT peel strength may not be balanced in a balanced manner.

  In order to select treatment conditions that do not cause excessive plasma treatment, it may be possible to weaken the voltage applied to the plasma generator, but in this case, the surface modification treatment that introduces functional groups or the like may be unstable depending on the conditions. Thus, it becomes difficult to achieve both the desired heat-resistant peel strength and PCT peel strength. In consideration of the circumstances of such plasma treatment, a desired result can be obtained if the conditions under which the plasma is stabilized can be selected even if the plasma treatment is excessive, and the excessive surface treatment can be removed.

  Therefore, in the present invention, ion beam processing is performed after plasma processing. The ion beam treatment has a high directivity of the ion beam to be irradiated, and has an action of scraping the surface of the object to be processed by sputtering the surface of the object to be processed with the ion beam to knock out the particles. By performing the ion beam irradiation treatment after the plasma treatment using this action, the surface of the modified layer that has been excessively modified by the plasma treatment in the previous stage can be removed. Since the plasma treatment conditions and the ion beam treatment conditions vary depending on the surface treatment apparatus and the long resin film, the treatment conditions may be appropriately determined by the following procedure.

  That is, first, the resin film F such as polyimide is dried by the heaters 217 and 218 at a drying temperature of 180 ° C. The dried resin film F is sent to the plasma chamber 234, where the plasma film is brought into close contact with the outer peripheral surface of the first cooling roll 236 in which the cooling water adjusted to 10 ° C. is circulating. For example, 200 sccm of oxygen gas is introduced into the generator 238 and plasma treatment is performed at a plasma voltage of 2000V. This plasma voltage is excessive for a polyimide film having a thickness of 25 μm. Here, the excessive plasma treatment is a treatment condition in which the PCT peel strength after processing a long resin film into a copper clad laminate is increased, but the heat-resistant peel strength is lowered. Note that nitrogen gas may be introduced into the plasma generator 238.

  Next, the resin film F subjected to the plasma treatment is sent to the ion beam chamber 239, where the resin film F is placed on the outer peripheral surface of the second cooling roll 241 in which the cooling water whose temperature is adjusted to 10 ° C. is circulated. While in close contact, for example, 50 sccm of oxygen gas is introduced into the ion beam generator 243 and the ion beam voltage is changed stepwise from 600 V to 3000 V to perform ion beam processing. In addition, the conveyance distance (namely, distance from the one end part of the longitudinal direction of the resin film F) of the resin film F when changing an ion beam voltage is recorded. And after performing the wet plating process as necessary to thicken the film, the obtained copper-clad laminate is subjected to each ion beam voltage area (from the transport distance when the ion beam voltage described above is changed). A test piece is cut out, and linear patterning is performed on each test piece to measure initial peel strength, PCT peel strength, and heat-resistant peel strength. Thereby, it is possible to define operating conditions that can favorably remove the surface of the modified layer that has been excessively modified by the plasma treatment by the ion beam treatment.

  Note that nitrogen gas may be introduced into the ion beam generator 243. In a series of these plasma treatment and ion beam treatment, the plasma treatment has a higher operating pressure, that is, the atmospheric gas pressure, than the ion beam treatment. Therefore, even if an ion beam is irradiated with the atmospheric pressure of the plasma treatment, the ion beam is not turned on and cannot be irradiated. Therefore, the plasma chamber 234 and the ion beam chamber 239 are isolated from each other and can be controlled separately so as to have different processing atmospheres.

  Next, another specific example of the surface treatment method of the present invention will be described with reference to FIG. The sputtering web coater shown in FIG. 2 is processed in the same manner as the apparatus shown in FIG. 1 except for the plasma chamber 334 and the ion beam chamber 339. 2 and 1, devices having the same code when the three-digit code hundreds are removed are the same devices. In the apparatus shown in FIG. 2, the plasma chamber 334 is not provided with a cooling roll. Therefore, the resin film F is not cooled from the back side, and plasma is irradiated from the plasma generator 338 in a so-called floating state.

  Also, the ion beam chamber 339 is not provided with a cooling roll, and therefore the resin film F is irradiated with an ion beam from the ion beam generator 343 in a floating state without being cooled from the back like the plasma chamber 334. . A resin film having a thickness of more than 25 μm can withstand a thermal load during plasma processing or ion beam processing, and thus plasma irradiation or ion beam irradiation can be performed even in a floating state. Also in the case of FIG. 2, the plasma chamber 334 and the ion beam chamber 339 are isolated from each other, and the atmospheric gas composition and pressure can be controlled separately.

  As described above, as a pre-treatment for the sputtering film forming treatment of the long resin film, after excessive plasma treatment is performed to increase the adhesion between the long resin film and the metal film, the plasma treatment is excessively modified. High quality copper-clad laminate with high initial peel strength, high PCT peel strength and high heat-resistant peel strength, and high adhesion by removing the surface of the modified layer by ion beam irradiation treatment A board substrate can be manufactured with high productivity.

  A flexible wiring board can be obtained by patterning this copper-clad laminate by, for example, a subtractive method. That is, a resist is formed on a copper clad laminate, a pattern is formed by a general method, and a metal film (for example, copper layer) portion not covered with the patterned resist is removed by etching. Thus, a flexible wiring board having a desired circuit pattern can be manufactured. As described above, the flexible printed circuit board thus produced has high adhesion and high quality, so that it can be used in devices that can be used in harsh environments such as notebook computers, digital cameras, and mobile phones. Therefore, the reliability of these devices can be improved.

  Since the vacuum film forming apparatus shown in FIGS. 1 and 2 performs the sputtering process, the magnetron sputtering cathode is provided as the film forming means. However, in the case of performing another vacuum film forming process. As a film forming means, CVD (chemical vapor deposition), vacuum deposition, or the like is provided. Further, as the copper-clad laminate, a structure in which a metal film such as a nickel-chromium alloy or copper is laminated on a long resin film is exemplified. In addition to the metal film, an oxide film and a nitride may be used depending on the purpose. The film forming method of the present invention can be used for forming a film, a carbide film or the like.

  Examples of the heat-resistant resin film used for the copper-clad laminate include a polyimide film, a polyamide film, a polyester film, a polytetrafluoroethylene film, a polyphenylene sulfide film, a polyethylene terephthalate film, and a polyethylene naphthalate film. Alternatively, a resin film such as a liquid crystal polymer film can be used. These resin films are preferable from the viewpoints of flexibility as a flexible substrate with a metal film, strength necessary for practical use, and electrical insulation suitable as a wiring material. Furthermore, the advantageous effects as described above can be obtained even if a single-wafer type resin film is subjected to surface treatment according to the above-described procedure of the surface treatment method for a long resin film.

[Comparative example]
Using a film-forming apparatus (sputtering web coater) for the resin film F shown in FIG. 3, a heat-resistant resin film with a metal film was prepared by sputtering film formation on a long heat-resistant resin film. A polyimide film “Kapton (registered trademark)” manufactured by Toray DuPont Co., Ltd. having a width of 500 mm, a length of 1000 m, and a thickness of 25 μm was used for a long heat-resistant resin film (hereinafter also referred to as resin film F). Of the devices indicated by the three-digit code in FIGS. 3 and 1, the devices that have the same code when the three-digit code hundreds are removed are the same device.

  For the can roll 123, a cylindrical member having a diameter of 800 mm and a width of 800 mm was used, and hard chromium plating was applied to the outer peripheral surface thereof. In addition, an IH heating roll having a diameter of 150 mm and an effective width of 500 mm is used for the front feed roll 122, and the peripheral speed of the can roll 123 is determined based on the speed reference so that the resin film F is strongly adhered to the outer peripheral surface of the can roll 123. It rotated at a speed 0.1% slower than the peripheral speed. The temperature of the can roll 123 was controlled to 60 ° C., and the temperature of the heaters 117 and 118 was controlled to 180 ° C.

The tension between the unwinding roll 114 and the winding roll 129 was 100N. A long resin film F wound around the unwinding roll 114 was set, and the tip of the resin film F was pulled out and attached to the winding roll 129 via a roll group such as a can roll 123. In this state, after evacuating the unwinding chamber 110, the plasma chamber 134, the film forming chamber 111, and the winding chamber 112 to 5 Pa with a plurality of dry pumps, further using a plurality of turbo molecular pumps and cryocoils. The air was exhausted to 3 × 10 ⁻³ Pa.

  A line type DC plasma generator was used as the plasma generator 138 used for improving the adhesion between the resin film F and the nickel-chromium thin film as the underlying metal layer. In addition, in order to reduce the thermal load of the plasma received by the resin film F, the resin film F was irradiated with plasma from the plasma generator 138 while being in close contact with the first cooling roll 136. The plasma generator 138 is connected to a DC power source (not shown), and the plasma intensity can be adjusted to a plasma voltage of 500 to 3000 V by voltage control. In this comparative example, the plasma voltage was 2000V. The plasma generator 138 was introduced with 500 sccm of oxygen gas.

  As a metal film to be formed on the resin film F, a nickel-chrome target is attached to the magnetron sputtering cathode 130 in order to form a copper thin film on a base metal layer made of a nickel-chromium thin film, and a magnetron sputtering cathode 131 is formed. A copper target was attached to ˜133. The transfer speed of the resin film F is set to 8 m / min, and the applied power to each sputtering cathode is adjusted so that a nickel-chromium thin film with a film thickness of about 10 nm and a copper thin film with a film thickness of about 100 nm thereon can be formed. did. Then, 300 sccm of argon gas was introduced into each cathode, and the film formation was started by controlling the power applied to each sputtering cathode.

  When conveyance of the long resin film F of 1000 m was completed, the voltage supply to the line type DC plasma generator 138 was stopped, and the supply of oxygen gas was also stopped. Subsequently, the power to the magnetron sputtering cathodes 130 to 133 was stopped, the supply of Ar gas was stopped, and the transport of the resin film F was stopped. Thereafter, the plurality of dry pumps, the plurality of turbo molecular pumps, and the cryocoil in the unwinding chamber 110, the plasma chamber 134, the film forming chamber 111, and the winding chamber 112 were stopped. Then, after introducing the atmosphere into the unwinding chamber 110, the plasma chamber 134, the film forming chamber 111, and the winding chamber 112, the resin film on which the metal film was formed was taken out.

A part of the resin film on which the metal film is formed by the above sputtering film formation is cut out, and copper copper plating is performed thereon to thicken the copper thin film layer, and the copper clad laminate having a copper layer with a film thickness of 8 μm The test piece was obtained. In accordance with JPCA BM01-11.5.3, an initial peel strength, a heat-resistant peel strength (150 ° C. × 168 hours), and a PCT peel strength (121 ° C. × 95% × 2 atm) were applied to the test piece of this copper-clad laminate. × 100 hours). As a result, the initial peel strength was 650 N / m, the heat-resistant peel strength was 300 N / m, and the PCT peel strength was 500 N / m.

[Example 1]
A long heat-resistant resin film was formed by sputtering using a long resin film vacuum film forming apparatus (sputtering web coater) shown in FIG. 1 to produce a heat-resistant resin film with a metal film. The vacuum film forming apparatus shown in FIG. 1 is the same as the empty film forming apparatus shown in FIG. 3 except that an ion beam chamber 239 is provided between the plasma chamber 234 and the film forming chamber 211. That is, in Example 1, after excessive plasma treatment was performed under the same conditions as in the comparative example, the surface of the excessively modified layer was removed by ion beam treatment. Specifically, the ion beam was irradiated from the ion beam generator 243 in a state where the resin film F was wound around the second cooling roll 241 and cooled from the back side after the plasma treatment.

  A line type DC ion beam generator was used as the ion beam generator 243, and oxygen gas was introduced at 50 sccm. A DC power source (not shown) is connected to the ion beam generator 243 so that the intensity of the ion beam can be adjusted with an ion beam voltage of 500 to 3000 V by voltage control. Then, the film formation was started by setting the transport speed of the resin film F to 8 m / min so that a nickel-chromium thin film having a thickness of about 10 nm and a copper thin film having a thickness of about 100 nm thereon could be formed. During film formation, the ion beam voltage was changed stepwise from 600V to 3000V at 200V intervals. The transport distance of the resin film F when the ion beam voltage was changed was recorded.

  And when the long resin film F was conveyed about 500 m with the conveyance speed of 8 m / min, the conveyance speed was changed to 6 m / min. When the conveyance speed of the resin film F is set to 6 m / min, the applied power to each sputtering cathode is set so that a nickel-chromium thin film with a film thickness of about 10 nm and a copper thin film with a film thickness of about 100 nm thereon can be formed. It was adjusted. Then, the ion beam voltage was changed stepwise from 600 V to 3000 V in steps of 200 V while recording the transport distance of the resin film F as described above. Thus, the film-forming process was performed until 1000 m conveyance of the long resin film F was completed. When the transfer speed was 8 m / min, the total power applied to the sputtering cathode was 80 kW, and when the transfer speed was 6 m / min, the total power applied to the sputtering cathode was 60 kW. A copper clad laminate was produced in the same manner as in the comparative example except for the above.

[Example 2]
A long heat-resistant resin film was used to form a heat-resistant resin film with a metal film by performing sputtering film formation on the long heat-resistant resin film using a long-film-resin vacuum film forming apparatus (sputtering web coater) shown in FIG. In the vacuum film forming apparatus shown in FIG. 2, the plasma chamber 334 and the ion beam chamber 339 are not provided with cooling rolls. Therefore, in Example 2, plasma processing and ion beam processing were performed in a floating state. A copper clad laminate was produced in the same manner as in Example 1 except for the above.

[Evaluation]
A test piece was cut out for each ion beam irradiation condition from the resin film on which the metal film was formed in Example 1 at a conveyance speed of 8 m / min, and the ion beam was also applied to the part formed at a conveyance speed of 6 m / min. A test piece was cut out for each irradiation condition. Electrolytic copper plating was performed on the surface of the copper thin film layer for these test pieces, so that the film thickness of the copper layer was 8 μm. The initial peel strength, heat-resistant peel strength (150 ° C. × 168 hours), and PCT peel strength (121 ° C. × 95% × 2 atm × 100 hours) were measured according to JPCA BM01-11.5.3. These peel strength data are plotted in FIGS. 4 and 5, respectively.

  From the graphs of FIGS. 4 and 5, it can be seen that as the ion beam voltage increases, the PCT peel strength decreases and the heat-resistant peel strength improves. As described above, the heat-resistant resin film substrate is subjected to plasma treatment in which hydrophilic functional groups such as carboxyl groups and hydroxyl groups are introduced in the vicinity of the surface in order to improve the adhesion with the metal film. If the plasma treatment is performed, the modified layer of polyimide becomes too thick, and the underlying metal layer is oxidized due to oxygen contained in the modified layer. As a result, the heat-resistant peel strength (150 ° C. × 168 hours) is significantly reduced compared to the PCT peel strength (121 ° C. × 95% × 2 atm × 100 hours).

  It can be seen that the effect of removing the surface of the excessively modified layer by this plasma treatment depends on the voltage of the ion beam. That is, when the ion beam voltage is increased from 600 V, an optimum region in which high PCT peel strength and high heat-resistant peel strength are compatible with each other by appropriately removing the modified layer appears. When the voltage of the ion beam is further increased, this modified layer is almost removed and the effect of the plasma treatment is lowered. By performing the subsequent operation under the conditions of this optimum region, it is possible to produce a copper-clad laminate with high initial peel strength and high adhesion that combines high PCT peel strength and high heat-resistant peel strength. become.

  The resin film formed in Example 2 was similarly cut out and thickened to a thickness of 8 μm, and the initial peel strength, heat-resistant peel strength, and PCT peel strength were measured. Results were obtained. From this result, it was found that the polyimide film having a thickness of 25 μm can be pretreated well even in the floating state.

F Long resin film 110 Unwinding chamber 111 Deposition chamber 112 Winding chamber 114 Unwinding roll 115, 121, 125, 128 Tension sensor roll 116 Heater box 117, 118 Heater 119, 120, 126, 127, 135, 137 Free Roll 122 Front feed roll 123 Can roll 124 Rear feed roll 129 Winding rolls 130, 131, 132, 133 Magnetron sputtering cathode 134 Plasma chamber 136 Cooling roll 138 Plasma irradiation device 210 Unwinding chamber 211 Film forming chamber 212 Winding chamber 214 Winding Out roll 215, 221, 225, 228 Tension sensor roll 216 Heater box 217, 218 Heater 219, 220, 226, 227, 235, 237, 240, 2 2 Free roll 222 Front feed roll 223 Can roll 224 Rear feed roll 229 Winding roll 230, 131, 132, 133 Magnetron sputtering cathode 234 Plasma chamber 236, 214 Cooling roll 238 Plasma irradiation device 239 Ion beam chamber 243 Ion beam generator 310 Unwinding chamber 311 Deposition chamber 312 Winding chamber 313 Heat resistant resin film substrate 314 Unwinding roll 315, 321, 325, 328 Tension sensor roll 316 Heater box 317, 318 Heater 319, 320, 326, 327, 335, 337, 340, 342 Free roll 322 Front feed roll 323 Can roll 324 Rear feed roll 329 Winding roll 330, 331, 332, 333 Magne Ron sputtering cathodes 334 plasma chamber 338 plasma generator 339 ion beam chamber 343 ion beam generator

Claims (8)

A surface treatment method prior to the film formation by a dry plating method on a resin film in a reduced pressure atmosphere, after performing plasma processing of irradiating flop plasma on at least one surface of the resin film was irradiated with the plasma The surface of the modified layer modified by the plasma treatment is removed by performing an ion beam treatment that irradiates the surface with an ion beam. In the ion beam treatment, a previously determined ion beam voltage and peel strength are obtained. In the above correlation, when the ion beam voltage is decreased, the ion beam voltage is equal to or higher than the ion beam voltage when the heat-resistant peel strength starts to decrease and when the ion beam voltage is increased, the ion when the PCT peel strength starts to decrease. A resin film surface treatment method comprising applying an ion beam voltage within a range of a beam voltage or less . 2. The surface of the resin film according to claim 1, wherein the plasma treatment irradiates the plasma under a condition that a PCT peel strength after processing into a copper clad laminate by the film formation is higher than a heat-resistant peel strength. Processing method.   The resin film surface treatment method according to claim 1, wherein a treatment atmosphere of the plasma treatment and a treatment atmosphere of the ion beam treatment are different from each other.   The surface treatment method for a resin film according to any one of claims 1 to 3, wherein the resin film is a long resin film conveyed by roll-to-roll.   The long resin film is cooled from a surface opposite to a surface irradiated with the plasma and the ion beam on the surface of the long resin film. Item 5. A resin film surface treatment method according to Item 4. A method of forming a film on a long resin film under a reduced pressure atmosphere,
The surface of the long resin film is subjected to the surface treatment by the surface treatment method according to claim 4 or 5, and thereafter, the surface of the long resin film is subjected to the surface treatment and is formed by a dry plating method. Film forming method. A method for producing a copper clad laminate having a laminate structure by forming a base metal layer on the surface of a long resin film without using an adhesive, and forming a copper layer on the surface of the base metal layer,
The surface of the long resin film is subjected to surface treatment by the surface treatment method according to claim 4 or 5, and then the base metal layer and the copper layer are sequentially formed by a dry plating method. A manufacturing method of a laminated board. The method for producing a copper-clad laminate according to claim 7, wherein the dry plating method is a sputtering method.

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