JP2008284844A - Film with conductive thin film and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain a desired sheet resistance in a large area uniformly even in the case when a film thickness of a metal film is so thin as about 10 nm, to attain, specifically, a means for making the sheet resistance uniform by only adjusting the film thickness by finding a means for easily forming the film having a continuous structure, to make it unnecessary to make the surface atomic composition or structure of a conductive thin film distributed, by making the sheet resistance adjustable by only adjusting the film thickness, and thereby to attain the metal film having a uniform surface tension. <P>SOLUTION: This film with the conductive thin film has a constitution that at least one side of a flexible base being ≥500 mm wide and consisting of a polymer is covered with the conductive thin film satisfying the conditions (1) to (3): (1) the distribution of the sheet resistance in the width direction of the base is <15%; (2) the distribution of the film thickness in the width direction of the base is ≥15%; and (3) the distribution of the film thickness in the width direction of the base is convex downward. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sensor member or circuit member that is lightweight, flexible, high quality, and inexpensive. In particular, the present invention relates to a film with a conductive thin film having uniform sheet resistance and surface tension even when the thickness of the conductive thin film is as thin as about 10 nm.

  Conductive thin films are widely used for touch panels, chemical sensors, antenna circuits, film resistors, and the like. In the conductive films used for these, the uniformity of sheet resistance is regarded as important. For example, in the case of a relatively large area such as a touch panel, it is desired that the electrical characteristics have no in-plane distribution and have linearity with respect to the distance between the electrodes. Further, in the case of a relatively small area such as a chemical sensor, it is desired to reduce individual differences in sheet resistance as much as possible. Furthermore, in a position sensor, a chemical sensor, etc., in order to easily detect a minute current signal as a stable voltage signal, it is desired to increase the sheet resistance of the conductive thin film to about 10Ω / □ to 1 kΩ / □, for example. . In addition, it is one of the important required characteristics that a resist or a protective film can be uniformly applied to the conductive thin film.

  On the other hand, these conductive thin films are generally formed by processes such as vapor-deposition, sputtering and plating using a roll-to-roll method using a flexible base material in order to produce them at low cost. In order to realize sheet resistance and surface coatability by such a manufacturing method, strict condition management in the width direction and the length direction is often required.

  For example, in a vacuum process such as vapor deposition or sputtering, the gas composition, plasma state, or substrate temperature in the vacuum apparatus is slightly nonuniform in the width direction or length direction (that is, processing time) of the substrate. . For this reason, as a result, it may cause non-uniformity in sheet resistance, surface tension, and the like of the conductive thin film. Further, in a submerged process such as plating, the concentration, flow rate, temperature, and the like of the liquid are slightly uneven in the width direction and the length direction of the substrate. For this reason, it may cause non-uniformity in sheet resistance, surface tension, and the like of the conductive thin film.

  Furthermore, when the thickness of the conductive thin film is as thin as 10 nm or less, the resistivity and surface tension are sensitively affected by the unstable crystal structure of the conductive thin film and the unintentional impurities mixed in the conductive thin film. Tend to be. In particular, when the substrate is organic, the molecular level shape of the substrate surface and the precipitation of organic components affect the formation of crystal nuclei in the conductive thin film, and the causal relationship between process conditions and film properties is well understood. It is extremely difficult to achieve uniform sheet resistance and surface tension.

As a general means for making the sheet resistance of a thin conductive thin film uniform, the film resistance is increased so that a desired sheet resistivity can be obtained by increasing the film thickness to a level at which uniform sheet resistance can be easily achieved. Increasing the rate can be mentioned. For example, in Patent Document 1, a means for realizing a film having a good resistance value distribution of 100 kΩ / □ to several MΩ / □ by setting the film thickness to 20 nm to 300 nm and the resistivity to about 10 ⁻² Ω · cm. It is disclosed.

As another means for making the sheet resistance uniform, a method of performing resistance control by partially performing ion implantation or impurity addition according to the resistance distribution of the produced conductive thin film is conceivable. However, this means complicates the process, and is limited to a small area and high value-added application such as an integrated circuit.
JP-A-8-337436

However, as in the method described in Patent Document 1, in order to realize a thin film having a resistivity of about 10 ⁻² Ω · cm, a limited method such as a sputtering method is used for a limited material such as an oxide semiconductor. It is necessary to create in. For this reason, a process and an installation will also become complicated and expensive. On the other hand, when a thin film of 100Ω / □ or more is to be realized with a metal film, it is necessary to make the film thickness as thin as about 10 nm or less. For this reason, it has been extremely difficult to realize a stable and uniform sheet resistance. In addition, increasing the resistivity of the thin film to increase the thickness of the thin film is undesirable in terms of economy and environmental load because it increases material costs, input energy during production, and requires production time. .

  As described above, as a factor that makes it difficult to realize a film having a uniform sheet resistance, in a thin film having a thickness of approximately 10 nm or less, crystal nuclei are dissipatively present on the surface of the base material and do not grow into a sufficiently continuous film. It seems that they are involved.

  Accordingly, an object of the present invention is to achieve a desired sheet resistance uniformly in a large area even when the thickness of the metal film is as thin as about 10 nm. Specifically, by finding a means for easily forming a film having a structure in which crystal nuclei are continuously present, it is possible to realize a means for making the sheet resistance uniform only by adjusting the film thickness. Further, in the present invention, by making it possible to adjust the sheet resistance only by adjusting the film thickness, it is not necessary to have a distribution in the surface atomic composition and structure of the conductive thin film, and a metal film having a uniform surface tension is realized. For the purpose.

The above problems are solved by the present invention described below. That is, the film with a conductive thin film according to the present invention has a conductive thin film satisfying the following conditions (1) to (3) on at least one surface of a flexible substrate made of a polymer having a width of 500 mm or more. It is covered.
(1) Substrate width direction distribution of sheet resistance of the conductive thin film is less than 15% (2) Substrate width direction distribution of film thickness is 15% or more (3) Substrate width direction distribution of film thickness protrudes downward

  The sheet resistance value of the conductive thin film may be 50Ω / □ to 300Ω / □.

  The film thickness of the conductive thin film is preferably in the range of 5 nm to 15 nm.

  The distribution of the contact angle of the conductive thin film with pure water in the substrate width direction is preferably within a range of 10 degrees.

  The conductive thin film includes at least one noble metal selected from the group consisting of palladium, gold, platinum, silver, rhodium, iridium, and ruthenium with 95 atm% or more of elements constituting the conductive thin film, or any of the noble metals An alloy containing 95 atm% or more is preferable.

  In the conductive thin film, it is preferable that 95 atm% or more of elements constituting the conductive thin film is palladium.

  You may have the layer which contains a transition metal element 50atm% or more in the interface of the said conductive thin film and the flexible base material which consists of the said polymer.

  The flexible substrate is preferably made of polyethylene terephthalate or polyethylene naphthalate and has a thickness in the range of 10 μm to 250 μm.

  The film with a conductive thin film is a metal element supplied in a rare gas atmosphere of 10 Pa or less while winding a flexible substrate made of a polymer, and when the conductive thin film is continuously formed by a sputtering method, Manufacture can be achieved by increasing the amount of the supplied metal element at both ends of the substrate in the width direction of the substrate as compared with the central portion in the width direction of the substrate.

  The amount of the metal element supplied may be a preset distribution amount in the width direction.

  In the film with a conductive thin film of the present invention, a film having a structure in which crystal nuclei exist continuously is formed. As a result, the sheet resistance can be made uniform only by adjusting the film thickness, so that a desired sheet resistance can be realized uniformly in a large area.

  Further, the sheet resistance can be adjusted only by adjusting the film thickness. As a result, a metal film having a uniform surface tension can be formed.

  Hereinafter, the film with a conductive thin film of this invention is demonstrated in detail using drawing. FIG. 1 is a conceptual diagram illustrating the concept of a film with a conductive thin film having a structure in which a transition metal layer is provided between a flexible substrate and a conductive thin film. In the example of FIG. 1, the structure of the cross section in the width direction of the film with an electroconductive thin film in which the electroconductive thin film 3 was provided on the flexible base material 1 via the transition metal layer 2 is shown.

  In the example of this figure, a transition metal layer 2 is provided. On the other hand, the film with a conductive thin film of the present invention may have a configuration in which a conductive thin film satisfying a predetermined condition is coated on at least one surface of a predetermined flexible substrate. With this configuration, even if no transition metal layer is provided, a desired sheet resistance can be achieved uniformly in a large area, and the distribution of the surface atomic composition and structure of the conductive thin film is not required. It has the effect of the present invention that a conductive thin film having a uniform surface tension can be obtained.

[Flexible substrate]
The flexible substrate 1 used in the film with a conductive thin film of the present invention may be a polymer. The flexible substrate 1 is not a glass but a polymer is used for the following reason. When a material such as glass with strong interatomic bonds is used as the base material, it is difficult for the atoms to mix on the surface of the base material. It is considered that it is difficult to form a continuous film until the film thickness is sufficiently thick. On the other hand, when the bonding energy between atoms constituting the substrate surface is relatively small like a polymer, the substrate surface is formed in the process where the atoms forming the conductive thin film aggregate on the substrate surface to form a film. It is thought that this is because part of the atoms constituting the electrode and part of the atoms forming the conductive thin film are mixed to easily form a continuous high resistance thin film in the plane direction. Therefore, when a polymer is used as the substrate, it is easy to form a conductive thin film having a uniform sheet resistance with a continuous structure. In addition, by increasing the width of the base material, the conductive thin film may be formed on the base material surface having a large area per unit time.

  Specific examples of the polymer are preferably polyethylene terephthalate or polyethylene naphthalate. Polyethylene terephthalate or polyethylene naphthalate is preferable because it has a six-membered ring in the molecular structure and is mechanically and thermally strong. Further, it is preferable to have a six-membered ring because the adhesion to the transition metal can be increased. Furthermore, it is preferable because it is less expensive than polyimide and polyamide.

  A more preferred flexible substrate 1 is polyethylene terephthalate. This is because polyethylene terephthalate is easy to form the conductive thin film 3 and is easily adaptable to various processes such as cutting, bending and laminating in the final processing step. Polyethylene terephthalate is preferable because it has good insulating properties, so that the sheet resistance can be determined only by the characteristics of the conductive thin film 3.

  The film thickness of the flexible substrate 1 is preferably in the range of 10 μm to 250 μm and the length in the range of 500 m to 5000 m. It is preferable that the thickness of the flexible substrate 1 is 10 μm or more because sufficient mechanical and thermal strength can be obtained and processability can be improved. Moreover, since the external shape of a roll can be restrained by setting it as 250 micrometers or less, continuous processing can be lengthened. This is preferable because the conditions of the conductive thin film forming process are stable and variations in sheet resistance can be suppressed.

  The width of the flexible substrate 1 is preferably in the range of 500 mm to 3000 mm. In the present invention, even when a relatively thin conductive thin film 3 is formed, a film having a continuous structure can be formed. Therefore, even when the substrate width is increased to about 3000 mm, the conductive thin film 3 having a uniform sheet resistance can be realized. When the substrate width is 500 mm or less, the productivity is low, so it is preferable to set the width to 500 mm or more. On the other hand, in a narrow film having a substrate width of 500 mm or less, a sheet resistance having a distribution in the substrate width direction of less than 15% can be easily obtained. On the other hand, if the thickness is 3000 mm or more, the conductive thin film forming apparatus is undesirably increased in size and cost and the factory space is increased. If a flexible long substrate is used, the conductive thin film can be easily and continuously coated at a relatively low cost by the roll-to-roll method.

[Transition metal layer]
When the transition metal layer 2 is provided at the interface between the conductive thin film 3 and the flexible substrate 1 made of the polymer, the transition metal easily binds to the carbon atoms constituting the polymer, and also forms a complex with the six-membered ring. Easy to do. Therefore, it is effective for realizing a structure that is strongly bonded to the polymer surface and is thermally stable. Therefore, when a transition metal is imparted to the surface of the flexible substrate 1, it can be used as an anchor when forming a noble metal film having low reactivity such as palladium. When the amount of transition metal at the interface is small, a metal that is difficult to bind to the polymer tends to form islands and form a discontinuous film.

  Examples of the transition metal that can be used include known transition metals. Specifically, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, molybdenum, or an alloy containing any of these can be given. In particular, titanium, vanadium, chromium, nickel, molybdenum, or an alloy containing any of these is preferable because it is difficult to chemically corrode. Further, since nickel is a magnetic material by itself, it is difficult to make a thin film by magnetron sputtering, and therefore an alloy with another metal is preferably used as a target. More preferably, an alloy containing 70 to 95% by weight of nickel and 5 to 30% by weight of chromium or titanium is used as a target material and is formed by magnetron sputtering.

  The transition metal layer 2 is a mixed layer that is substantially homogeneous in the width direction and includes atoms constituting the surface of the flexible substrate 1 and noble metal atoms constituting the conductive thin film 3. In the transition metal layer 2, it is preferable that these transition metal elements contain 50 atm% or more.

  The transition metal layer 2 is sufficient if it has a thickness of several atomic layers. When a transition metal layer containing a transition metal element of 50 atm% or more is provided at the interface between the flexible substrate 1 made of a polymer and the conductive thin film 3, the conductive thin film 3 has a continuous structure even at a thin film thickness of about 10 nm. Is preferable because it is easy to form.

[Conductive thin film]
The material used for the conductive thin film 3 of the film with a conductive thin film of the present invention is, for example, a noble metal such as palladium, gold, platinum, silver, rhodium, iridium, ruthenium, or an alloy composed of these noble metals. Good. When a noble metal is used as the material of the conductive thin film 3, it is less susceptible to chemical reactions such as oxidation, hydroxylation, acid corrosion, sulfidation, and salt damage during film formation and storage or use after film formation. preferable. Among these noble metals, palladium is preferable because of its relatively high chemical stability and particularly low price among these noble metals.

  The content of these metals in the conductive thin film 3 is not particularly limited but is preferably 95 atm% or more. In the case of using an alloy, it may be configured to contain 95 atm% or more of any of the noble metals. It is preferable to contain 95 atm% or more of these metals in the conductive thin film 3 because the chemical stability of the surface is increased.

  The conductive thin film 3 has (1) a base material width direction distribution of sheet resistance of the conductive thin film 3 of less than 15%, (2) a base material width direction distribution of film thickness of 15% or more, ( 3) It is necessary to satisfy the three conditions that the distribution of the film thickness in the substrate width direction is convex downward. By satisfying this condition, even when the thickness of the conductive thin film 3 is as thin as about 10 nm, a film having a structure in which crystal nuclei exist continuously can be obtained.

(Distribution of sheet resistance in the substrate width direction)
The sheet resistance value of the conductive thin film is preferably in the range of 50Ω / □ to 300Ω / □. More preferably, it is 60Ω / □ to 250Ω / □, and further preferably 70Ω / □ to 200Ω / □. A sheet resistance of 50 Ω / □ or more is preferable because a sufficient output can be easily obtained when a current signal is detected as a voltage signal when used for a position sensor, a chemical sensor, or the like. If the sheet resistance is higher than 300Ω / □, it is difficult to flow a weak current.

  In the present invention, the “width” of the film substrate with a conductive thin film refers to a direction perpendicular to the winding direction if the film is a roll. If the film is a single sheet and the winding direction of the film can be identified, the direction is perpendicular to the winding direction. If the film is a single sheet and the winding direction of the film cannot be discriminated, if either direction satisfies the above conditions, that direction is taken as the width direction.

  Further, “the distribution of the sheet resistance in the width direction of the substrate is less than 15%” means that the position 50 mm from one end in the width direction of the substrate is X1, the position in the width direction center of the substrate is X3, and the other of the substrate Let X5 be the position 50 mm from the end of X1, X2 be the position of one end and the midpoint of X3, and X4 be the position of the other end and the midpoint of X3. When the sheet resistance values at positions X1, X2, X3, X4, and X5 are R1, R2, R3, R4, and R5, the maximum value of R1 to R5 is Rmax, and the minimum value is Rmin, {(Rmax−Rmin ) / Rmin × 100} <15 (%).

  The smaller the distribution of the sheet resistance of the conductive thin film in the substrate width direction, the better. However, if it is less than 15%, it is acceptable because it is within the allowable range and the yield can be increased.

(Thickness distribution in the substrate width direction)
The distribution of the film thickness in the substrate width direction is such that the film thicknesses at the positions X1, X2, X3, X4, and X5 are T1, T2, T3, T4, and T5, respectively, the maximum value of T1 to T5 is Tmax, and the minimum value is When Tmin, {(Tmax−Tmin) / Tmin × 100} ≧ 15 (%) may be satisfied.

  When the film quality (for example, density, impurity concentration, crystal state, etc.) of the conductive thin film 3 in the width direction is different, it is difficult to realize a uniform sheet resistance in the width direction. Therefore, by making the thickness direction distribution of the film thickness larger than the width direction distribution of the sheet resistance, a uniform sheet resistance in the width direction can be easily realized.

  The distribution of the film thickness in the substrate width direction may be distributed so as to protrude downward. Specifically, if the film thicknesses at the positions X1, X2, X3, X4, and X5 are T1, T2, T3, T4, and T5, T1> T2> T3 and T3 <T4 <T5 are satisfied. Good.

  If the film quality of the conductive thin film 3 in the width direction of the base material (for example, density, impurity concentration, crystal state, etc.) is constant, the thickness of the conductive thin film 3 in the width direction of the base material is made constant. The sheet resistance in the width direction can be less than 15%. However, in practice, it is difficult to reduce the sheet resistance in the width direction of the base material to less than 15% simply by forming the conductive thin film 3 having a continuous structure as described above. It turns out that it tends to be high. The reason for this is not clear, but it is presumed that the density of the conductive thin film 3 is smaller at the end portion in the substrate width direction than at the center portion in the substrate width direction. Therefore, in the present invention, in order to make the sheet resistance in the substrate width direction of the conductive thin film 3 constant, the film thickness in the substrate width direction of the conductive thin film 3 is not made constant, but the substrate width is dared. The film thickness at both ends in the direction is made larger than the film thickness at the center in the width direction. Specifically, the substrate width direction distribution of the film thickness is convex downward, and the substrate width direction distribution of the film thickness is 15% or more, that is, more deliberately than the substrate width direction distribution of the sheet resistance. Make it bigger.

In the present invention, the thickness of the conductive thin film 3 is preferably in the range of 5 nm to 15 nm. When the thickness of the conductive thin film 3 exceeds 15 nm, a special material such as an oxide semiconductor having a resistivity of 3 × 10 ⁻⁴ Ω · cm or more is used in order to make the sheet resistance 300Ω / □ or less. There is a need. On the other hand, when the film thickness of the conductive thin film 3 is 15 nm or less, a conductor material having a resistivity of 3 × 10 ⁻⁴ Ω · cm can be used, and a metal material can be used, which is preferable. Moreover, when the film thickness of the conductive thin film 3 is less than 5 nm, it becomes difficult to form a continuous film, and it tends to greatly vary in the direction in which the sheet resistance increases. Therefore, the thickness of the conductive thin film 3 is preferably 5 nm or more.

[Contact angle]
In the film with a conductive thin film of the present invention, the distribution of the contact angle with the pure water of the conductive thin film 3 in the substrate width direction is preferably within 10 degrees. The “distribution of the contact angle in the substrate width direction” means a difference between the maximum value and the minimum value (maximum value−minimum value) among the contact angles at the positions X1, X2, X3, X4, and X5. When the distribution of contact angles in the substrate width direction is within 10 degrees, it is preferable that the extent of the contour becomes uniform when pattern printing is performed on ink, silver paste, resist, and the like.

  The contact angle may be measured by a known method. For example, the sample for measurement is allowed to stand for 24 hours in an atmosphere at a temperature of 25 ° C. and a relative humidity of 50%, and then the contact angle of a predetermined amount of distilled water is measured using a contact angle meter.

(Production method)
The film with a conductive thin film of the present invention can be produced as follows.
In the present invention, the conductive thin film is continuously formed by sputtering in a rare gas atmosphere in the range of 0.2 Pa to 2.0 Pa while winding the flexible substrate.

  When the conductive thin film 3 is formed using a sputtering method, a mixed layer of a very thin metal and an organic material is formed on the surface of a flexible substrate made of a polymer, and the dissipative nucleus of the conductive thin film material is suppressed. It is preferable because it is easy.

  As a condition when forming the conductive thin film 3 by the sputtering method, when the pressure is set in a range of 0.2 Pa to 2.0 Pa and a deposition rate of 1 nm / s or more in a rare gas atmosphere of 99% or more, It is preferable because sheet resistance and surface tension can be obtained stably. In particular, when the pressure in the sputtering atmosphere is 10 Pa or less, high kinetic energy particles flying toward the flexible substrate can be prevented from losing kinetic energy due to collision, and the number is sufficient to break the polymer bond. It becomes possible to supply the flexible substrate with energy of about eV. Thereby, it is easy to suppress nucleation of the conductive thin film, and it is preferable because it is easy to realize a conductive thin film having a stable sheet resistance even at a thin film thickness of about 10 nm.

  As the rare gas to be used, any of argon, helium, neon, krypton, and xenon can be used. In particular, it is preferable to use argon because sheet resistance and surface tension can be obtained stably.

  In the method for producing a film with a conductive thin film of the present invention, it is preferable to supply a predetermined amount of metal in the substrate width direction distribution to the surface of the flexible substrate. A method for supplying a predetermined amount of metal in the width direction distribution onto the substrate surface can be realized by installing a correction plate for adjusting the opening width between the target material of the sputtering apparatus and the substrate holding portion. . It is preferable to select a material having a linear expansion coefficient close to that of the conductive thin film 3 for the correction plate because the film attached to the correction plate is less likely to fall off during the film formation. Further, it is preferable to select a non-magnetic correction plate, since it does not adversely affect the magnetic field when performing magnetron sputtering.

  Thus, by increasing the amount of the metal element supplied to the flexible substrate at both ends of the substrate width direction compared to the center portion of the substrate width direction, The film thickness can be increased, and consequently the sheet width direction distribution of the conductive thin film can be made less than 15%.

  Since the conductive thin film thus obtained can have a continuous structure even if the film thickness is as thin as about 5 nm, the sheet resistance can be changed only by changing the film thickness even in the film thickness range of 5 to 15 nm. Can be adjusted. Therefore, it is preferable because it is easy to realize a uniform sheet resistance in the substrate width direction only by the film thickness.

  In addition, the film with a conductive thin film of the present invention and the manufacturing method thereof are not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

  EXAMPLES Examples will be given below to describe the present invention in detail, but the present invention is not limited to the examples.

[Evaluation of base material]
Hereinafter, the results of examining the dependence of the resistance value of the palladium film on the thickness of the sputtered film when the base material is glass and polyethylene terephthalate (hereinafter referred to as “PET”) will be described.

(Experiment 1) Comparison of Pd / Glass Substrate and Pd / PET Sample First, a specific sputtering method will be described below. The substrate is a 25 mm × 50 mm size crown glass (thickness 1 mm, flatness 0.01 mm or less [JIS R3703 test method]) or a polyester film (Toray Industries, Inc., product number E20, thickness 100 μm). Installed in a state where the resistance value between two opposing sides in a 25 mm rectangular area can be measured.The cathode is a magnetron type and circular with a diameter of 76 mm.The distance between the target and the substrate is 100 mm, and a shutter that can be opened and closed in the middle. In addition, a quartz oscillator film thickness meter was placed at a position within 30 cm on the same plane as the base material, and the sputter film thickness was measured, and after purging the inside of the sputter chamber to the 10 ⁻³ Pa level, purity 99 .99% Argon was introduced at 10 sccm, and the opening ratio of the exhaust valve was adjusted to adjust the pressure in the chamber to 1.0 Pa. After closing the shutter, DC current 0.05A was applied and pre-sputtering was performed for 10 seconds, and then the shutter was opened to form a film for 10 seconds. After reading the value promptly, pre-sputtering and film formation were carried out again, and the film thickness dependency of the resistance value was examined by repeating this operation, where “sccm” means 0 ° C., 1.013 × 10 It is a numerical value representing the volume flow rate at ⁵ Pa (1 atm (atm)) in units of ml / min.

  In addition, the film thickness corrected the value of the quartz-crystal-type film thickness meter with the value which measured the palladium film produced on the glass substrate with the surface roughness meter (model number: SE-3400) made from Kosaka Laboratory. . Specifically, a palladium film having a film thickness of approximately 1 μm was prepared, and a step between the substrate and the palladium surface determined by a surface roughness meter was defined as a palladium film thickness. A calibration curve is created by obtaining the film thickness measured by the surface roughness meter and the value of the crystal resonator type film thickness meter, and the value (film thickness value) of the crystal resonator type film thickness meter by the value of the surface roughness meter ( (Film thickness value). In addition, the sheet resistance value is corrected by a value obtained by measuring the sheet resistance of the palladium film formed on the surface of each of the glass substrate and the polyethylene terephthalate film using Loresta (Loresta GP, model number: MCP-T600) manufactured by Dia Instruments Co., Ltd. did. Using a TFP probe manufactured by Dia Instruments Co., Ltd., the sheet resistance value at the center of the 25 mm × 25 mm square sample (intersection of diagonal lines of the square) was measured. Further, the ratio of the product of palladium film thickness and sheet resistance value at palladium film thicknesses of 10 nm and 30 nm {(sheet resistance value at palladium film thickness of 10 nm) × 10 nm} / {(sheet resistance value at palladium film thickness of 30 nm) × 30 nm} Was calculated. When the palladium film has continuity, the sheet resistance value is inversely proportional to the palladium film thickness in accordance with Ohm's law, so that the product ratio is ideally a minimum value of 1. If the product ratio is 1.5 or less, the change in the resistance value with respect to the change in the film thickness is small, and the resistance value can be easily adjusted by controlling the palladium film thickness, which is good.

  FIG. 2 is a double logarithmic graph showing the film thickness dependence of the resistance value of the palladium sputtered film when a glass substrate or a polyethylene terephthalate film is used as a base material. 2. “Pd / PET” in FIG. 2 is a result in the case where a palladium sputtered film is provided on glass, and “Pd / PET” is a result in the case of providing a paradium sputtered film on a polyethylene terephthalate film. In this way, a bending point is observed in the vicinity of a film thickness of 10 nm when any base material is used, but the use of a glass substrate is more remarkable. When the glass substrate is used, the ratio of the product of the palladium film thickness and the sheet resistance is as large as 160. The main cause of this is that palladium is dissipatively aggregated on the glass substrate to form island-like nuclei below about 10 nm. However, it is considered that the sheet resistance value increases due to a decrease in continuity in the surface direction.

  On the other hand, in the case of a polyethylene terephthalate substrate, the ratio of the product of the palladium film thickness and the sheet resistance value is 1.4, which is asymptotic to 1, so that it is difficult for palladium to form a nucleus, and a continuous structure is developed. it seems to do. Although the cause of such a result is not known in the case of a polyethylene terephthalate substrate, some of the elements constituting the surface of a polymer material such as polyethylene terephthalate are in the palladium film due to the incidence of high-speed particles such as palladium or argon. There is a possibility that a so-called mixing phenomenon that is taken in is occurring. As a result, the interface between the polymer base material such as polyethylene terephthalate and the conductive thin film such as palladium has a continuous structure with a gradient composition in the thickness direction, and as a result a continuous structure in the surface direction. Even when the thickness of the layer is small, it is considered that conductivity is easily developed. Such a mixing phenomenon at the interface is not limited to that caused by the kinetic energy of particles in the sputtering method, but is also caused by thermal energy in the vapor deposition method, electrochemical energy in the plating method, and the like. This is considered to be remarkable when a material having a relatively low binding energy is used as a substrate. That is, it can be seen that by using a polymer such as polyethylene terephthalate as a substrate, the sheet resistance can be easily controlled by adjusting the film thickness even at a very thin film thickness of about 10 nm.

(Experiment 2) Pd / NiCr / PET
Next, the result of investigating the film thickness dependence of the resistance value when a nickel chromium alloy layer is formed as a transition metal layer on the surface of the polyethylene terephthalate substrate and then a palladium film is formed thereon as a conductive layer will be described. The composition ratio of nickel chromium was 80% nickel and 20% chromium. The same sputtering apparatus as in Experiment 1 was used, and the setting was the same as in Experiment 1 except that the target was replaced with nickel chrome. Thereafter, the inside of the sputter chamber was evacuated to a level of 10 ⁻³ Pa, and then 10 sccm of argon having a purity of 99.9999% was introduced, the opening ratio of the exhaust valve was adjusted, and the pressure in the chamber was adjusted to 1.0 Pa. Thereafter, a direct current of 0.05 A was applied with the shutter closed, and pre-sputtering was performed for 10 seconds. Thereafter, the shutter was opened and a film corresponding to about 1 nm was formed in 3 seconds. At this time, the resistance value between the substrate terminals was 50 MΩ or more and could not be measured. Thereafter, the chamber was once opened and the target was exchanged with palladium, and then the film thickness dependency of the resistance value was examined by the same method and conditions as in Experiment 1.

  The results are shown together with the results of Experiment 1 in FIG. “Pd / NiCr / PET” in FIG. 2 is a result when a nickel chrome alloy layer and a palladium sputtered film are provided on a polyethylene terephthalate film. Thus, when a palladium film is formed on a polyester substrate via a nickel chromium layer, it is possible to suppress an increase in resistance in a region where the film thickness is about 10 nm or less than when a nickel chromium layer is not used. Recognize. Further, since the ratio of the product of the palladium film thickness and the resistance value is 1.4, which is asymptotic to 1, it can be determined that the palladium film has continuity. It can be seen that the sheet resistance of the conductive layer can be more easily controlled by the film thickness by using the nickel chromium layer at the interface between the polymer substrate and the conductive layer.

[Example]
The measuring method of each physical property value in Examples and Comparative Examples of the present invention is as follows. The position of 50 mm from one end of the roll sample is X1, the position of the center of the base in the width direction is X3, the position of 50 mm from the other end of the base is X5, and the position of one end and the middle point of X3 is The position of the middle point of X2, the other end and X3 is X4. In the case of a substrate having a width of 1000 mm, the positions are 50, 250, 500, 750, and 950 mm from the end.

(1) Sheet resistance value of conductive thin film A 100 mm square measurement sample centered on the positions of X1, X2, X3, X4, and X5 was cut out from the roll sample. After leaving the sample in an atmosphere of 20 ° C. and 50% relative humidity for 24 hours, based on JIS-C-2151 (2006 edition), a surface resistance meter (Loresta GP, model number: MCP-) manufactured by Dia Instruments Co., Ltd. T600) and a probe (model number: TFP) were used, and sheet resistance was measured at a test voltage of 10V. The center point of the measurement sample was measured. Five measurement samples were measured at each measurement position, and the average value was taken as the sheet resistance value at each position of the roll sample.

  The distribution of the sheet resistance in the substrate width direction is a numerical value (%) representing the difference between the maximum value and the minimum value of the sheet resistance value at each position as a percentage of the minimum value {(maximum value−minimum value) × 100 / minimum value}. If the distribution of the sheet resistance in the substrate width direction is less than 15%, the uniformity of the sheet resistance in the substrate width direction is good.

(2) Film thickness of conductive thin film A 100 mm square measurement sample centered on the positions of X1, X2, X3, X4, and X5 was cut out from the roll sample. The film thickness of the conductive thin film was calculated from the intensity (unit: cps) of fluorescent X-rays using an energy dispersive X-ray fluorescence analyzer (model number: OURSTEX 160) manufactured by Hours Tech Co., Ltd. First, a conductive thin film having a film thickness of about 1 μm was prepared, and the substrate and the surface of the conductive thin film were measured using fluorescent X-ray intensity and a surface roughness meter (model number: SE-3400) manufactured by Kosaka Laboratory. The film thickness of the conductive thin film was measured from the step. The center point of each measurement sample was measured. Next, since the intensity of fluorescent X-rays of the conductive thin film is proportional to the film thickness, the film thickness of the conductive thin film of the sample was calculated (the film thickness of the conductive thin film of the sample (nm) = approximately 1 nm thick). Film thickness (measured value) of conductive thin film (nm) × fluorescent X-ray intensity (cps) of sample / X-ray intensity (cps) of conductive thin film having a thickness of approximately 1 μm. Five measurement samples were measured at each measurement position, and the average value was taken as the film thickness at each position of the roll sample.

  The substrate width direction distribution of the thickness of the conductive thin film is a numerical value (%) representing the difference between the maximum value and the minimum value of the thickness of the conductive thin film at each position as a percentage of the minimum value (%) {( Maximum value−minimum value) × 100 / minimum value}.

(3) Contact angle A 100 mm square measurement sample centered on the position of X1, X2, X3, X4, and X5 was cut out from the roll sample. A sample for measurement was allowed to stand for 24 hours in an atmosphere at a temperature of 25 ° C. and a relative humidity of 50%, and then a distilled water with a dropping amount of 1.6 mg was used using a contact angle meter (model number: CA-X) manufactured by Kyowa Interface Science Co., Ltd. The contact angle of was measured. The center point of the measurement sample was measured. The measurement was performed within 3 minutes from the time when the measurement sample was cut out from the roll sample. Five measurement samples were measured at each measurement position, and the average value was defined as the contact angle at each position of the roll sample.

  The distribution of the contact angle of the conductive thin film in the substrate width direction is a numerical value (%) representing the difference between the maximum value and the minimum value of the contact angle of the conductive thin film at each position as a percentage of the minimum value (%) {( Maximum value−minimum value) × 100 / minimum value}.

(4) Atm% of outermost surface element and its metal species A 100 mm square measurement sample centered on the position of X3 was cut out from the roll sample. Using an X-ray photoelectron spectrometer (model number: SSX-100) manufactured by SSI, the metal species of the outermost surface element is obtained from the photoelectron energy, and the ratio of the outermost surface element (atm%) from the photoelectron peak intensity ratio of each surface element. ) The center point of the measurement sample was measured. Five samples for measurement were measured, and the average value was defined as atm% of the outermost surface element of the sample.

(5) Atm% of transition metal at interface and metal species A 100 mm square measurement sample centered on the position of X3 was cut out from a roll sample. Using a PHI X-ray photoelectron spectrometer (product name: Quantera SXM), the metal species of the transition metal at the interface was determined from the photoelectron energy. In addition, the element composition profile in the depth direction of the conductive thin film was measured by Ar ion etching, and the maximum value of the transition metal ratio at the interface obtained from the peak intensity ratio of the photoelectrons was set to atm%. The center point of the measurement sample was measured. Five samples for measurement were measured, and the average value was defined as atm% of the transition metal at the interface of the sample.

(6) Thickness of base material A 100 mm square measurement sample centered on the position of X3 was cut out from the roll sample. Based on JIS-C-2151 (2006 edition), it measured using the micrometer. The center point of the measurement sample was measured. Five samples for measurement were measured, and the average value was taken as the thickness of the sample substrate.

Example 1
A palladium thin film was continuously formed on the film by a sputtering method while winding a polyester film (Toray "Lumirror" E20) roll having a thickness of 188 µm and a width of 1000 mm in a vacuum chamber. Sputtering was performed in a state where argon gas was flowed into the vacuum chamber evacuated until the pressure became 5 × 10 ⁻³ Pa or less so that the pressure became 0.2 Pa. In Example 1, a correction plate was installed between the target material of the sputtering apparatus and the base material holding part.

(Comparative Example 1)
A palladium thin film was formed on the polyester film in the same manner as in Example 1 except that the correction plate was not installed.

The film which formed and wound the palladium thin film of Example 1 and Comparative Example 1 was taken out from the vacuum chamber, and rewound in the atmosphere by a film winder. The pass line from the roll on the feeding side to the roll on the winding side was 15 m, and the time when the palladium surface was in contact with the air by rewinding at a speed of 5 m / min was 3 minutes. The room where rewinding was performed was adjusted so that the temperature was 23 ° C. Furthermore, it adjusted so that absolute humidity might be set to 9.27 g / m < ³ > using the humidifier and the dehumidifier.

  In both Example 1 and Comparative Example 1, the outermost layer of palladium was 99.99 atm%. The contact angle was in the range of 35 to 45 degrees.

(Example 2)
A nickel chrome thin film was continuously formed on the film by sputtering while winding a polyester film (Toray "Lumirror" E20) roll having a thickness of 188 µm and a width of 1000 mm in a vacuum chamber. Sputtering was performed in a state where argon gas was flowed into the vacuum chamber evacuated until the pressure became 5 × 10 ⁻³ Pa or less so that the pressure became 0.2 Pa. Next, a palladium film was formed on the nickel chromium layer by the same method as in Example 1.

The film formed by forming the nickel chrome thin film and the palladium thin film was taken out from the vacuum chamber and rewound in the atmosphere by a film winder. The pass line from the roll on the feeding side to the roll on the winding side was 15 m, and the time when the palladium surface was in contact with the air by rewinding at a speed of 5 m / min was 3 minutes. The room where rewinding was performed was adjusted so that the temperature was 23 ° C. Furthermore, it adjusted so that absolute humidity might be set to 9.27 g / m < ³ > using the humidifier and the dehumidifier.

  The palladium on the outermost layer of the membrane was 99.99 atm%. The abundance of the nickel chromium layer at the palladium-film interface was 50 atm%. The contact angle was in the range of 35 to 45 degrees.

Table 1 shows the sheet resistance value and palladium film thickness of the outermost layer of Example 1, Example 2, and Comparative Example 1. The film thicknesses at the positions X1, X2, X3, X4, and X5 in Example 1 and Example 2 satisfy the relationship of T1>T2> T3 and T3 <T4 <T5, respectively, and the substrate width of the palladium film thickness The direction distribution has a downwardly convex shape. The substrate width distribution of the film thickness was 17%, which was 15% or more. As a result, the sheet resistance at the center in the width direction of the substrate can be made equal to the sheet resistance at both ends in the width direction, and the distribution of the sheet resistance in the width direction of the substrate is good at less than 15%. On the other hand, in Comparative Example 1, the palladium film thickness distribution in the substrate width direction was formed to be 4% smaller. The film thicknesses at the positions X1, X2, X3, X4, and X5 do not satisfy the relationship of T1>T2> T3 and T3 <T4 <T5. For this reason, the distribution of the sheet resistance in the substrate width direction was 15% or more, which was poor.

  The film with metal film and the method for producing the same of the present invention can be applied to a touch panel, a chemical sensor, an antenna circuit, a film resistor, and the like.

FIG. 1 is a conceptual diagram illustrating a film with a conductive thin film according to the present invention. FIG. 2 is a diagram showing the results of investigating the dependence of the resistance value of the palladium film on the sputtering film thickness when the base material of the present invention is glass and polyethylene terephthalate (hereinafter referred to as “PET”).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flexible base material 2 Transition metal layer 3 Conductive thin film

Claims (10)

A film with a conductive thin film, wherein a conductive thin film satisfying the following conditions (1) to (3) is coated on at least one surface of a flexible substrate made of a polymer having a width of 500 mm or more.
(1) Substrate width direction distribution of sheet resistance is less than 15% (2) Substrate width direction distribution of film thickness is 15% or more (3) Substrate width direction distribution of film thickness protrudes downward   The film with a conductive thin film according to claim 1, wherein a sheet resistance value of the conductive thin film is 50Ω / □ to 300Ω / □.   The film with a conductive thin film according to claim 1 or 2, wherein a film thickness of the conductive thin film is in a range of 5 nm to 15 nm.   The base film width direction distribution of the contact angle with the pure water of the said conductive thin film is a range within 10 degrees, The film with a conductive thin film in any one of Claims 1-3.   The conductive thin film includes at least one noble metal selected from the group consisting of palladium, gold, platinum, silver, rhodium, iridium, and ruthenium with 95 atm% or more of elements constituting the conductive thin film, or any of the noble metals The film with a conductive thin film according to any one of claims 1 to 4, which is an alloy including 95 atm% or more.   The conductive thin film-attached film according to any one of claims 1 to 4, wherein 95% or more of elements constituting the conductive thin film is palladium.   The film with a conductive thin film according to any one of claims 1 to 6, further comprising a transition metal layer containing a transition metal element of 50 atm% or more at an interface between the conductive thin film and the flexible base material made of the polymer.   The film with a conductive thin film according to claim 1, wherein the flexible substrate is made of polyethylene terephthalate or polyethylene naphthalate and has a thickness in the range of 10 μm to 250 μm. While winding a flexible substrate made of a polymer, supplying a metal element in a rare gas atmosphere of 10 Pa or less, and when forming a conductive thin film continuously by a sputtering method,
The manufacturing method of the film with an electroconductive thin film in any one of Claims 1-8 whose quantity of the said metal element supplied is large in the base-material width direction both ends compared with a base-material width direction center part. The method for producing a film with a conductive thin film according to claim 9, wherein the amount of the metal element to be supplied is a preset distribution amount in the width direction.

Images