JP2015201629A - Laminate for circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate for a circuit hardly causing disconnection due to damage to a resin base material even when a circuit is formed using a subtractive method, without using a high-cost protective film and a wet-type hard coat layer, in order to solve such a problem that damage present in a resin base material is not filled even when a metal layer is deposited thereon by means of a dry coat method or the like, so that a discontinuous part is formed in the metal layer, and a defect of circuit disconnection easily occurs when a wiring circuit is formed so as to straddle the discontinuous part using a subtractive method.SOLUTION: A laminate for a circuit includes a metal layer on at least one side of a resin base material, the metal layer having a total stress of -250 N/m or more and 0 N/m or less, or a laminate for a circuit includes a metal layer on at least one side of a resin base material, the metal layer having a residual distortion of -3×10or more and -1×10or less.

Description

  The present invention relates to a circuit laminate that can be suitably used as a material for a circuit board manufactured by a subtractive method. In particular, the present invention relates to a circuit laminate which is a material for forming a circuit having a line width of 200 μm or less.

  In manufacturing a circuit board, a laminate in which a metal layer is formed on an insulating substrate is used as a material.

  As a manufacturing method of the laminate, a three-layer type in which a metal foil and an insulating substrate are bonded with an adhesive, and a method in which good adhesion strength such as a sputtering method is easily obtained on the insulating substrate without using an adhesive. There is known a two-layer type in which a metal layer is formed and then the metal layer is increased by electrolytic plating as necessary (Patent Document 1). The thickness of the metal foil is limited in the three-layer type (for example, when the metal is copper, it can be easily obtained except for a special product with a carrier is 9 to 35 μm), whereas in the two-layer type, Since the metal layer thickness can be selected from a wider range, the metal layer thickness is suitably used for thin demands such as 0.05 to 10 μm.

  When the metal layer is thin, there are advantages that the processing speed when forming a circuit by the subtractive method can be increased, high-precision processing such as a line width of 10 μm or less can be performed, and that the bending resistance is excellent. In addition, since the step between the etched portion and the non-etched portion is small, there is an advantage that bubbles are not easily caught when the wiring circuit is formed and bonded to another base material via an adhesive.

JP 2010-163654 A

  However, the laminate described in Patent Document 1 may be caused by scratches on the base material, and scratches may remain on the metal layer formed thereon, and the formed wiring circuit may be disconnected. In other words, even if the metal layer is formed by vapor deposition or the like, scratches existing on the base material are not buried even when the metal layer is formed by a vapor deposition method. Forming a wiring circuit by the active method tends to cause a problem of circuit disconnection.

  As a method for solving this problem, it is conceivable to arrange a protective film on the base material from immediately after the base material preparation to immediately before the metal layer film formation so that the base material is not damaged. In some cases, a protective film winding mechanism in the metal layer deposition apparatus is required, which is not preferable.

  In addition, a hard coat layer composed of a silica component, an acrylic component, etc. can be provided by wet coating after scratches have occurred on the substrate, so that the scratches can be filled and not damaged by subsequent transport. The cost may increase by the amount, which may be undesirable.

  Also, if the method of forming the circuit is not a subtractive method but a semi-additive method, the metal layers on both sides of the scratch can be grown by wet plating to eliminate the scratch, but the process is more than that of the subtractive method. It may become complicated and a plating facility may be required.

  The present invention has been made in view of the above circumstances, and even if a substrate is damaged, even if a circuit is formed by a subtractive method without using an expensive protective film or wet hard coat layer, the substrate is An object of the present invention is to provide a laminate for a circuit that is less likely to cause disconnection due to scratches.

In order to solve the above problems, the circuit laminate of the present invention has the following configuration.
(1) A circuit laminate having a metal layer on at least one side of a resin base material, wherein the total stress of the metal layer is −250 N / m or more and 0 N / m or less.
(2) A laminate for a circuit having a metal layer on at least one surface of a resin base material, and the residual strain of the metal layer is -3 × 10 ⁻³ or more and −1 × 10 ⁻⁴ or less.
(3) The laminate for a circuit according to (1) or (2), wherein an easy-adhesion layer is provided on at least one side of the resin base material.
(4) The laminated body for a circuit according to (3), wherein the easily adhesive layer has a thickness of 10 nm to 300 nm.
(5) The laminate for a circuit according to any one of (1) to (4), wherein the metal layer has a thickness of 0.05 μm or more and 10 μm or less.

  According to the present invention, as described below, even if the resin base material has a scratch, even if a circuit is formed by the subtractive method without using a protective film or a wet hard coat layer, the breakage due to the resin base material scratch Thus, it is possible to provide a laminated body for a circuit that is less likely to cause the problem.

It is a cross-sectional schematic diagram of an example of the laminated body for circuits of 1st embodiment of this invention. It is a cross-sectional schematic diagram of an example of the laminated body for circuits of 1st embodiment of this invention. It is a cross-sectional schematic diagram which shows the total stress direction of the metal layer of the laminated body for circuits of a prior art. It is a cross-sectional schematic diagram which shows the total stress direction of the metal layer of the laminated body for circuits of 1st embodiment of this invention. It is a cross-sectional schematic diagram of an example of the laminated body for circuits of 2nd embodiment of this invention. It is a top view of an evaluation pattern. It is a side surface schematic diagram at the time of calculating | requiring a curvature radius from the curvature of the laminated body for circuits.

  The circuit laminate of the present invention has a metal layer on at least one side of the resin substrate. For example, a layer such as an easy adhesion layer or an adhesion layer may be sandwiched between the resin base and the metal layer, or another layer may be provided on the opposite side of the metal layer from the resin base.

  As the resin substrate constituting the circuit laminate of the present invention, known resins such as PET (polyethylene terephthalate), PEN (polyethylene naphthalate), polyaramid, polyimide, polycarbonate, polyethylene, and polypropylene can be used. The resin base material may have scratches with a depth of submicron to several microns on its surface during its manufacture or during conveyance during processing. In particular, a resin substrate having a softer surface than glass or ceramics may be easily damaged. There are various mechanisms for generating scratches. For example, there are protrusions on the transport roll and rubbing, or dust of a size of several microns is placed on the resin substrate and pressed by the transport roll. In particular, a film that has undergone a longitudinal stretching process due to a difference in peripheral speed of the roll (for example, a sequential biaxially stretched polyester film that undergoes lateral stretching after the longitudinal stretching process) is excellent in optical characteristics and mechanical properties, while in the longitudinal stretching process. May cause scratches.

  The occurrence of scratches can be reduced by improving the precision of the transport mechanism and strengthening the cleaning, but it is difficult to completely eliminate the damage, and the cost may increase due to the precision of the transport mechanism and the enhanced cleaning for reducing the damage. However, if it has this invention, even if the above-mentioned damage | wound exists in a resin base material, when forming a wiring circuit by a subtractive method, the laminated body for circuits with a low possibility of producing a disconnection can be provided. Details will be described below.

  An object of the present invention is that the scratches on the resin base material remain even after the metal layer is formed, causing disconnection during circuit formation. For example, even if there is a scratch on the resin base material, the surface of the scratch should be connected and not broken if the metal layer is formed so as to grow in the vertical direction. However, in reality, the problem of disconnection has occurred.

  As a result of intensive studies, the authors have found that the tensile stress of the metal layer is one of the reasons why the scratches are not buried during the formation of the metal layer. That is, during the formation of the metal layer, a new tear is formed on the surface of the resin base material due to the tensile stress of the metal layer, so that even if the metal layer is formed beyond the depth of the scratch, it is disconnected.

  In the circuit laminate of the present invention, the total stress of the metal layer is −250 N / m or more and 0 N / m or less. In the present invention, when the total stress of the metal layer is less than 0 N / m, compressive stress (that is, curl with the metal layer facing outward), and when the total stress is greater than 0 N / m, tensile stress (that is, metal Curl with the layer inward). Further, when the total stress is zero, that is, 0 N / m, it means that neither compressive stress nor tensile stress exists.

  In the present invention, if the total stress of the metal layer is -250 N / m or more and 0 N / m or less, that is, if the total stress is the compressive stress or the total stress is zero, the circuit laminate is less prone to disconnection. Even if the total stress is less than −250 N / m (that is, even if the compressive stress is larger), the effect of preventing the formation of a new tear on the surface of the resin substrate during the formation of the metal layer remains the same, but the curl increases. Therefore, handling such as film conveyance and alignment becomes difficult. From the viewpoint of curling suppression, the total stress of the metal layer is more preferably −100 N / m or more and 0 N / m or less, further preferably −30 N / m or more and 0 N / m or less, and −15 N / m or more and 0 N / m or less. Particularly preferred.

As another aspect of the laminate for a circuit of the present invention, it is preferable that the residual strain of the metal layer is -3 × 10 ⁻³ or more and −1 × 10 ⁻⁴ or less. The residual strain is expressed using the strain tensor ε, and a negative value indicates compression. Compression means that the interstitial distance is narrower than the interstitial distance of the bulk metal. A residual strain of −1 × 10 ⁻⁴ or less is preferred because the metal atoms tend to spread as much as possible to a more stable interstitial distance, so that it becomes difficult for new tears to occur on the surface of the resin substrate during the formation of the metal layer. Even if the residual strain is smaller than −3 × 10 ⁻³ , there is no change in the effect that it is difficult to generate a new tear on the surface of the resin substrate during the formation of the metal layer. Handling may be difficult.

The circuit laminate of the present invention preferably has an easy adhesion layer on at least one side of the resin substrate. The easy-adhesion layer is a layer disposed to increase the adhesion strength when the resin base material is coated with wet or dry, and a soft resin having a glass transition temperature lower than that of the resin base material is often used. For example, polyester resin or acrylic resin. There are two types of easy-adhesion layers: an in-line coat that coats the resin base material at the time of manufacture, and an off-line coat that winds up once after the resin base material is manufactured and then unwinds and applies the easy-adhesion layer. There are merits in the many choices of materials. On the other hand, due to the softness of the easy-adhesion layer, there may be a problem that the surface is easily damaged during the process, which may be a trade-off with the adhesion enhancement with the coating layer. In that case, the effect of using the metal layer having the above-described compressive stress or the metal layer having no total stress, or the metal layer having a residual strain of −3 × 10 ⁻³ or more and −1 × 10 ⁻⁴ or less. The effect of using becomes remarkable.

  The thickness of the easy adhesion layer is preferably 10 nm or more and 300 nm or less, more preferably 30 nm or more and 200 nm or less, further preferably 50 nm or more and 150 nm or less, and particularly preferably 80 nm or more and 120 nm or less.

  If it is less than 10 nm, it is difficult to coat uniformly, and it may become mottled and the adhesion strength may vary depending on the position. When the thickness exceeds 300 nm, a soft resin is present on the surface, and a deep flaw may be caused by contact with the roll of the process.

  The metal layer of the present invention preferably has a thickness of 0.05 μm or more and 10 μm or less. If the thickness of the metal layer is less than 0.05 μm, the circuit may be disconnected when a circuit having a large number of pinholes and smaller than the pinhole size is formed. If the thickness exceeds 10 μm, the etching in the horizontal direction also proceeds while the etching in the vertical direction takes a long time with respect to the resin base material, so that it may be difficult to process into a fine pattern by the subtractive method.

  The metal layer in the present invention preferably contains at least one metal element selected from the group consisting of gold, silver, copper, aluminum, magnesium, tungsten, cobalt, zinc, titanium, nickel, chromium and iron. From the viewpoint of imparting high conductivity, the metal layer is more preferably composed of at least one metal element selected from the group consisting of gold, silver, copper, and aluminum, and considering the balance with cost More preferably, the metal layer is made of copper.

  Hereinafter, the present invention including the first embodiment will be described in detail with reference to the drawings showing the embodiment.

[First embodiment]
FIG. 1 is a conceptual diagram illustrating a first embodiment of the present invention.

  The resin substrate 1 is made of, for example, PET (polyethylene terephthalate), PEN (polyethylene naphthalate), polyaramid, polyimide, polycarbonate, polyethylene, polypropylene, or the like. Since the resin base material is easily available in a roll form as compared with a glass or ceramic base material, it can be processed with a roll-to-roll and has excellent productivity.

  In order to prevent a short circuit of the formed circuit, it is preferable that the surface of the resin base material 1 has an insulating property. If the material of the resin base material 1 is not insulating, the surface insulating property is given by, for example, a surface oxidation treatment or the like. It is preferable to do.

  Although the thickness of the resin base material 1 is not specifically limited, Preferably it is 1 micrometer or more and 5,000 micrometers or less, More preferably, they are 10 micrometers or more and 500 micrometers or less, More preferably, they are 20 micrometers or more and 250 micrometers or less. If the resin base material is too thin, it may be difficult to handle such as being easily broken in the middle of conveyance, and if it is too thick, the volume occupied by the circuit board in the electronic device may become large, and downsizing of the device may be difficult.

  It is preferable that the resin base material 1 has transparency because it can be applied to an electromagnetic wave shielding film, a transparent conductive film for a touch panel, a transparent heater, and the like. In the present invention, the resin base material having transparency means that the total light transmittance of the resin base material is 20% or more, and preferably 50% or more.

  The easy adhesion layer 3 is preferably applied to the surface of the resin substrate 1. Examples of the resin used for the easy adhesion layer include polyester resin and acrylic resin.

  The resin substrate 1 may have scratches 2. As for the size of the scratch, the width and depth are often several tens of nm to several μm. If the width and depth of the scratch 2 present on the resin substrate 1 are several tens of nanometers or less, they are often buried when the easy-adhesion layer 3 is formed. Scratches larger than 10 μm often cause problems in appearance in addition to the problem of disconnection, and it is often difficult to identify the cause of occurrence.

  As shown in FIG. 2, the scratch 2 may be present in the easy-adhesion layer 3. In this case, the depth of the scratch 2 is shallower than the film thickness of the easy-adhesion layer 3, and it seems that the scratch 2 is buried during the subsequent formation of the metal layer 4 and no disconnection occurs. Depending on the direction and size, a part of the scratch 3 may break and expand, which may cause disconnection.

  A metal layer 4 is present on the side of the easy adhesion layer 3 opposite to the resin substrate 1. The metal layer 4 has a total stress of −250 N / m or more and 0 N / m or less. As described above, when the metal layer has a tensile stress, a stress in a direction such as the stress direction 5 of the metal layer in FIG. 3 works. This stress propagates through the metal layer 4 to the inside of the wound 2. In general, since the total stress of the layer is proportional to the thickness, this stress increases as the thickness increases in the process of forming the metal layer. As a result, the edge portion 6 of the scratch 2 is thinner than the portion deposited on the plane, and is cracked by stress. If the metal layer 4 is cracked, the resin base material 1 and the easy-adhesion layer 3 are less rigid than the metal layer 4, and therefore follow the metal layer 4, resulting in a tear 7. Even if the metal layer 4 is further formed (increased) after the tear 7 has occurred, the tear 7 further spreads due to the increase in tensile stress due to the increase in thickness. Therefore, the metal layer 4 is straddled across the tear 7. It is difficult to connect.

  However, when the total stress of the metal layer 4 is −250 N / m or more and 0 N / m or less as in the present invention, the edge portion 6 of the scratch 2 having a low strength of the metal layer 4 is pushed from both sides. It becomes difficult to break (FIG. 4). Thus, even if there is a scratch 2 on the resin substrate 1, it is possible to produce a circuit laminate that does not cause a discontinuous portion of the metal layer 4 that causes disconnection.

  Even if the total stress of the metal layer 4 is less than −250 N / m, the effect of preventing the discontinuity of the metal layer 4 from being lost is not lost, but the curl of the resin base material becomes large, so that the handling point May be undesirable.

The residual strain of the metal layer 4 is preferably −3 × 10 ⁻³ or more and −1 × 10 ⁻⁴ or less. If it is −1 × 10 ⁻⁴ or less, the metal atoms tend to spread as much as possible to a more stable interstitial distance, so that it becomes difficult for new tears to occur on the surface of the resin substrate during formation of the metal layer.

  The metal layer 4 preferably has a thickness of 0.05 μm to 10 μm, more preferably 0.2 μm to 5 μm, further preferably 0.3 μm to 3 μm, and more preferably 0.5 μm to 1 μm. It is particularly preferred that

  The metal layer 4 is more preferably a layer having a total content of metal elements (on the basis of the number of atoms) of 50 atomic% or more and 100 atomic% or less, more preferably 95 atoms in the total 100 atomic% of the metal layer 4. % Or more and 100 atomic% or less. Similarly, when the metal layer is present on both sides of the resin base material, the total metal element content (on the basis of the number of atoms) of the metal layer on the other side is 100 atomic% or more in 100 atomic% of the entire metal layer. The layer is more preferably an atomic% or less layer, more preferably a 95 atomic% or more and 100 atomic% or less layer.

  The metal layer 4 may contain nonmetallic elements such as oxygen, nitrogen, and carbon, but the total content of nonmetallic elements (based on the number of atoms) in 100 atomic% of the entire metal layer 4 is 5 atomic%. The following is preferable. When the total content of the nonmetallic elements in the metal layer 4 exceeds 5 atomic%, sufficient conductivity may not be obtained.

The metal layer 4 can be formed by a known method such as a vacuum deposition method, an ion plating method, or a sputtering method, or a combination thereof such as a plating method after the sputtering method. The point that adhesion strength with the resin base material is easily obtained, the point that the total stress of the metal layer 4 is easily controlled to −250 N / m or more and 0 N / m or less, or the residual strain of the metal layer 4 is −3 × 10 ^{− The} ion plating method and the sputtering method are more preferable because they are easily controlled to ³ or more and −1 × 10 ⁻⁴ or less. In order to set the total stress to −250 N / m or more and 0 or less, or to set the residual strain to −3 × 10 ⁻³ or more and −1 × 10 ⁻⁴ or less, high-energy metal atoms are implanted into the metal layer 4 being formed. It is considered effective. The atoms in the metal layer 4 become more packed than the stable position by the implanted metal atoms, and the total stress is −250 N / m or more and 0 N / m or less (ie, compressive stress or total stress). Is zero), or the residual strain is -3 × 10 ⁻³ or more and −1 × 10 ⁻⁴ or less. With metal particles having low energy, the implantation becomes shallow, and the generation of compressive stress may be limited.

If the resin substrate is cooled during film formation of the metal layer or the film formation speed is increased, if the metal layer 4 is rapidly cooled after film formation, the phenomenon that the implanted metal atoms move to a stable position It can be limited by depriving the free energy of metal atoms, and a metal layer having a residual strain of less than −250 N / m or a residual strain of less than −3 × 10 ⁻³ can also be obtained. May become difficult to handle.

  In the ion plating method, the metal atoms vaporized from the molten metal material are partially cationized, and the film formation particles are accelerated by being attracted electrically toward the resin substrate. Can be easily supplied to the resin base material.

  In the sputtering method, ions of an inert gas such as argon collide with a target such as a metal, and thereby metal atoms ejected from the target adhere to the surface of an adherend (a film is deposited by sputtering). And the energy of the ejected metal atoms is larger than the energy of the metal particles by the vacuum deposition method.

  In addition to the film forming method, the film forming pressure is also important when supplying high-energy film forming particles to the resin substrate. When the film forming pressure is high, there are many gases and film forming particles present in the chamber, and there is a possibility that energy is lost due to collision and scattering with the gas before the film forming particles reach the resin substrate. Therefore, it is preferable that the film forming pressure is lower.

  A blackening layer (not shown) may be provided on the opposite side of the metal layer 4 from the resin base material 1. The blackening layer means that the contrast of the transmitted image is affected by the color and gloss of the surface of the metal layer when it is used in applications where this circuit laminate is visible, such as the electrode of an electromagnetic shielding film, the electrode of a touch panel, or the electrode of a transparent heater. It is suitable because it has an effect of preventing the decrease.

The blackening layer is preferably a solid film, and the reflection color when the circuit laminate is viewed from the side opposite to the resin base material is L ^* a ^* b ^* color system value L ^* ≦ 65 and − It is preferable that 20 ≦ a ^* ≦ 20 and −20 ≦ b ^* ≦ 20. The material for the blackening layer is not particularly limited, and examples thereof include nickel nitride, copper nitride, nickel oxide, and copper oxide.

  Although the thickness of a blackening layer is not specifically limited, 5 nm or more and 5,000 nm or less are preferable, and 10 nm or more and 1,000 nm or less are more preferable. When the thickness of the blackened layer is less than 5 nm, the amount of light transmitted through the blackened layer increases, and the above-described effects may not be sufficiently exhibited. If the thickness of the blackened layer exceeds 5,000 nm, there may be a resistance when conduction is obtained from the blackened layer surface with a contact type pin probe.

[Second Embodiment]
FIG. 5 is a conceptual diagram illustrating a second embodiment of the present invention.

  In the second embodiment, the adhesion layer 8 is provided between the easy adhesion layer 3 and the metal layer 4. The adhesion layer 8 is provided to ensure adhesion strength between the easy adhesion layer 3 and the metal layer 4, and the thickness is preferably 0.5 nm or more and 500 nm or less, and more preferably 1 nm or more and 100 nm or less. Yes, 1 nm to 50 nm is more preferable. If the thickness of the adhesion layer is smaller than 0.5 nm, a sufficient adhesion effect may not be obtained. In addition, even if the thickness of the adhesion layer exceeds 500 nm, the obtained adhesion does not increase further. From the viewpoint of cost, the thickness of the adhesion layer is preferably 500 nm or less.

  The adhesion layer 8 preferably contains at least one selected from the group consisting of titanium, nickel and chromium, for example. Since these elements have high activity, it is easy to form elements and compounds that constitute another layer. A layer containing a pure metal such as titanium, nickel, or chromium may be used, or a layer containing a compound containing titanium, nickel, or chromium such as nickel nitride or nichrome may be used.

  Note that the adhesion layer is preferably a layer in which the total content of titanium, nickel, and chromium elements (on the basis of the number of atoms) is 50 atomic% or more and 100 atomic% in the entire layer of 100 atomic%. When the ratio of elements other than these elements becomes large, it may be difficult to obtain the effects described above. Except for the presence of the adhesion layer 8, it is the same as the first embodiment.

[Third embodiment]
In the third embodiment, the metal layer 4 is formed by a vacuum deposition method in a low vacuum.

In general, the vacuum deposition method is easy to obtain a high film formation rate as compared with the sputtering method, and is suitable for producing a metal layer of 0.5 μm or more with high productivity. On the other hand, since the energy of metal atoms at the time of film formation is lower than that of the sputtering method, it is difficult to obtain the implantation effect, the total stress of the metal layer 4 is larger than 0 N / m (that is, tensile stress), and the residual strain is −1 ×. It tends to be larger than 10 ⁻⁴ .

  By introducing a gas into the chamber during vacuum deposition and lowering the degree of vacuum, a large number of minor cracks that do not reach the resin substrate can be generated uniformly on the surface of the metal layer, and the stress and strain of the metal layer can be dispersed. .

  That is, by introducing the gas, the possibility that the metal particles collide with the gas during the film formation is increased, and if the energy is made smaller than that in the normal vacuum deposition method, the stable position is reached after reaching the resin substrate. The phenomenon in which the metal atoms move to the surface of the metal film can be significantly suppressed, and new metal atoms arrive before the metal atoms become a uniform film, and fine cracks are likely to occur on the surface of the metal film. The tensile stress of a metal layer propagates as the number of constituent atoms increases, and concentrates on the edge of the metal layer. Actively utilizing the fact that tensile stress does not propagate over cracks, and forming a large number and uniform cracks to divide the metal layer into islands and limit the number of atoms that make up each island To disperse the stress applied to the ends of the island-like metal layer.

By doing so, the total stress of the metal layer can be −250 N / m or more and 0 N / m or less, or the residual strain of the metal layer can be −3 × 10 ⁻³ or more and −1 × 10 ⁻⁴ or less.

Examples of the gas to be introduced include inert gases such as argon and neon, oxygen, nitrogen, and the like. The degree of vacuum in the chamber is preferably 0.1 Pa or more and 10 Pa or less. When the degree of vacuum is higher than 0.1 Pa (the pressure is low), the collision between the metal particles and the gas is insufficient, and the total stress of the metal layer is −250 N / m or more and 0 N / m or less, or the residual strain of the metal layer is − It may not be 3 × 10 ⁻³ or more and −1 × 10 ⁻⁴ or less. If the degree of vacuum is lower than 10 Pa (high pressure), the probability that the metal particles are scattered by the gas increases, resulting in a decrease in the film formation rate and a decrease in the use efficiency of the material due to an increase in metal adhesion to the apparatus wall surface. There is a case.

[Usage]
By using the present invention, it is possible to provide a laminated body for a circuit that is less likely to cause disconnection when a wiring circuit is formed by a subtractive method even if a scratch is present on the resin base material. The present invention is for a circuit as a material for a transparent electrode for a touch panel, in which a long circuit having a width of several μm to several tens of μm and a long circuit extending from several m to several hundreds m is used as a lead-out wiring that cannot be disconnected even at one place. It is particularly suitable for a laminate.

(Measuring method)
(1) Total light transmittance of resin base material The total light transmittance of the resin base material was measured in accordance with JIS K7361-1 (established in 1997) using NDH4000 manufactured by Nippon Denshoku Industries Co., Ltd. The one with the larger value measured from both sides of the resin substrate was adopted.

(2) Thickness of resin base material The thickness of the resin base material was measured using a Digimatic indicator ID-CX manufactured by Mitutoyo Corporation. When measuring the resin base material which has an easily bonding layer on the surface, thickness was measured including the easily bonding layer, and it calculated | required by subtracting the thickness of the easily bonding layer calculated | required by the method of (3).

(3) Layer thickness The layer thickness was measured by cutting the circuit laminate by FIB (focused ion beam) method and observing the cross section by TEM (transmission electron microscope). The thickness of each layer was measured by selecting a layer formed on a non-scratched portion of the resin base material. In the easy-adhesive layer, particles made of silica or acrylic may be blended in order to impart easy slipping, but in measuring the thickness, the portion without particles was selected and measured. When it was difficult to distinguish between the easy-adhesion layer and the resin substrate, RuO ₄ staining, OsO ₄ staining, or double staining of both was performed on the sample cut out by the ultrathin section method in order to increase the contrast of the TEM image. You may perform said measurement later.

(4) Reflection color The reflection color was measured from the side opposite to the resin substrate of the circuit laminate using a spectrocolorimeter CM-2600d manufactured by Konica Minolta Co., Ltd. compliant with JIS Z8722 (established in 2009). . The C light source was used as the light source, and the 2 ° visual field and SCI (including specular reflection light) were measured.

(5) Disconnection rate As for the disconnection rate, dry film resist (trade name: Sunfort ADH-151) manufactured by Asahi Kasei E-Materials was bonded to the metal layer side of the circuit laminate, and exposed and developed through a photomask. .

  Next, the metal layer and the adhesion layer were partially removed with a ferric chloride aqueous solution, and the disconnection rate evaluation pattern circuit of FIG. 6 was obtained (in FIG. 6, either the metal layer or the adhesion layer was not removed. A portion remaining on the surface of the resin base material is defined as a line portion 21, and a portion from which all of the layers are removed is defined as a space portion 22. The pattern of the wiring circuit has a ninety-nine fold shape in which the width of the line portion 21 is 30 μm, the width of the space portion 22 is 50 μm, and a 40 mm long line is folded back and forth 25 times, and electrode pads 23 are arranged at both ends.

  Fifty patterns were prepared, and the disconnection rate was determined by measuring the resistance between the pads. The case where the pad-to-pad resistance exceeded 10 kΩ was regarded as a disconnection.

(6) Adhesion strength The adhesion strength of the metal layer to the resin substrate was evaluated by a cross-cut method according to JIS K5600-5-6 (established in 1999). Nichiban Co., Ltd. No. 405 and Nitto Denko Corporation No. Two types of No. 756 were used (No. 756 has higher adhesive strength).

(7) Total Stress of Metal Layer In determining the total stress of the metal layer, first, the film stress σ was determined from (Formula 1) from the warp of the circuit laminate after the metal layer was formed. When the adhesion layer was present, it was determined from the warp of the resin substrate after the adhesion layer and the metal layer were formed. In the present invention, the formation of a compressive stress metal layer having a total stress of −250 N / m or more and 0 N / m or less suppresses the formation of tears on the surface of the resin substrate. This is because it can also be applied to a metal layer.
σ = {E _S / 6 (1-ν _S )} × (h ² / l) × (1 / R ₀ ) (Formula 1)
(Equation 1) in, E _S is the Young's modulus of the resin substrate, [nu _S is Poisson's ratio of the resin base material, h is the thickness of the resin substrate, l (el) is a metal layer thickness, R ₀ is the warp Represents the radius of curvature. When the adhesion layer exists, l (el) is the total thickness of the metal layer and the adhesion layer.

  The Young's modulus and Poisson's ratio of the resin substrate were measured by the methods described later after the metal layer was removed by etching (if the adhesion layer is present, the adhesion layer and the metal layer). When the easy-adhesion layer was present, the measurement was performed with the resin base material and the easy-adhesion layer combined, and the Young's modulus of the resin base material of Formula 1 and the Poisson's ratio of the resin base material were used. The etching solution may be appropriately selected depending on the material constituting the metal layer or the adhesion layer. For example, when the material constituting the metal layer or the adhesion layer is copper, iron, or nickel, ferric chloride or cupric chloride is preferable, and when the material is gold, silver, or platinum, aqua regia is preferable. .

The curvature radius R ₀ of the warp of the resin base material was determined by cutting the laminate after forming the metal layer into a strip shape having a width of 10 mm and a length of 50 mm, and placing the cut sample on the flat surface 31 so that the metal layer side is on top. Was obtained from (Equation 2) as an arc when viewed from the long side.

R ₀ = (4H ² + D ² ) / 8H (Formula 2)
In Equation 2, R ₀ is the radius of curvature, H is the arrow height 32 of the arc, and D is the chord length 33 of the arc (FIG. 7).
Here, the sample was cut from the resin base material in four directions every 30 ° around an arbitrary point of the laminate, the four samples were measured, and the average value was defined as the film stress σ. .

  The total stress S of the metal layer was determined from (Equation 3). l (el) is the thickness of the metal layer. When the adhesion layer is present, l is the total thickness of the metal layer and the adhesion layer.

  S = σ × l (Formula 3).

  In addition, in the case of the laminated body which has a metal layer on both sides of a resin base material, the sample which removed the metal layer of one side by the method mentioned above is prepared, and total stress is measured. Similarly, a sample from which the metal layer on the other side has been removed is prepared, and the total stress is measured. In the present application, if the total stress of the metal layer on at least one side is −250 N / m or more and 0 N / m or less, “the resin substrate has a metal layer on at least one side, and the total stress of the metal layer is −250 N / m or more and 0 N / m or less ”.

(8) Young's modulus of resin base material Using a tensile tester (Tensilon UCT-100 manufactured by Orientec Co., Ltd.), a sample film having a width of 10 mm was set to a length between chucks of 50 mm (initial sample length), and the temperature A tensile test was performed at a tensile speed of 300 mm / min under the conditions of 25 ° C. and humidity 65% RH. The Young's modulus was obtained from the tangent of the rising portion of the stress-strain curve recorded in the tensile test.

(9) Poisson's ratio of resin base material The resin base material was cut into a strip shape having a length of 120 mm and a width of 20 mm, and a 10 mm square lattice was written in the center of the strip. In an atmosphere of 23 ° C. and 65% RH, set to a sheet width measuring device manufactured by Ayaha Engineering Co., Ltd. so as to have a test length of 110 mm, and using two high-performance laser dimension measuring devices manufactured by Keyence Co., Ltd. The dimensions of the long side direction and the short side direction of the lattice were each read. Thereafter, a load of 50 MPa was applied in the long side direction of the strip, and the dimensions in the long side direction and the short side direction of the lattice were read in the same manner. From the dimension before and after the load is applied, the change rate of the dimension in the long side direction (ΔL _L %) of the strip and the change rate of the dimension in the short side direction of the resin substrate (ΔL _S %) are calculated. The Poisson's ratio was calculated.
Poisson's ratio = (ΔL _S / ΔL _L ) (Formula 4).

(10) Residual strain of metal layer The residual strain of the metal layer was determined by a 2D method using a wide-angle X-ray diffraction method (microscopic X-ray diffraction).

  The resin base material with a metal layer was cut into a strip of approximately 12 mm × 9 mm, and fixed to the sample holder with a double-sided tape so that the metal layer was on the surface. At this time, when the laminate was curled with the metal layer inside, a double-sided tape of 2 mm × 2 mm was applied to the center position of the sample holder, and placed gently so that the approximate center of the laminate and the double-sided tape overlapped. If the laminate is curled with the metal layer on the outside, a 9 mm x 2 mm double-sided tape is applied to each end of the laminate in the longitudinal direction (the sample length is 12 mm, the same applies hereinafter) on the sample holder. Gently put it on.

  X-ray diffractometer is D8 DISCOVER μHR Hybrid manufactured by BrukerAXS, X-ray source is CuKα ray (using multilayer mirror), output is 50 kV, 22 mA, slit diameter is 1 mmφ pinhole, detector is 2D PSPC, camera length is It was 15 cm. The measurement range is 2θ = 89.8 °, ω = 44.9 ° (Cu (311) diffraction peak), φ = 20 °, 50 °, φ = 0 to 180 ° (30 ° step) in total 14 frames, The integration time was 600 seconds / frame.

  Here, the sample starts from an arbitrary angle, cut into four different directions every 30 °, and measured each. The residual strain perpendicular to the longitudinal direction of the sample is ε11, and the residual strain parallel to the longitudinal direction is ε22. These arithmetic average values were used as the residual strain of the metal layer.

In addition, in the case of the laminated body which has a metal layer on both sides of a resin base material, the sample which removed the metal layer of one side by the method mentioned above is prepared, and a residual distortion is measured. Similarly, a sample from which the metal layer on the other side has been removed is prepared, and the residual strain is measured. In the present application, if the residual strain of the metal layer on at least one side is −3 × 10 ⁻³ or more and −1 × 10 ⁻⁴ or less, “having a metal layer on at least one side of the resin substrate, the metal The residual strain of the layer is -3 × 10 ⁻³ or more and −1 × 10 ⁻⁴ or less ”.

(Example 1)
This will be described with reference to FIG.
A biaxially stretched PET (polyethylene terephthalate) film was used as the resin substrate 1. The thickness of the resin base material was 100 μm. The total light transmittance of the resin base material 1 was 92%. The easy adhesion layer 3 mainly composed of polyester having a thickness of 100 nm was applied to the resin substrate 1 by in-line coating.

A metal layer 4 (copper) was formed on one surface side of the resin base material (this is the upper surface side) by a DC magnetron sputtering method so as to have a thickness of approximately 1 μm by roll-to-roll. At this time, the distance between the surface of the copper target facing the resin substrate was 100 mm, and the power density supplied to the target was 3.79 kW / m ² . Further, argon was used as the sputtering gas, and the flow rate was adjusted so that the pressure in the chamber was 0.3 Pa.

  The thickness of the obtained metal layer was 0.96 μm, and the total stress of the metal layer was −26 N / m.

The residual strain of the obtained metal layer was −8.4 × 10 ⁻⁴ .

  The adhesion strength of the obtained laminate was No. When the tape of 405 is used, it is classified as 0 (no peeling on any grid). When 756 tape was used, category 2 peeling occurred. When a predetermined pattern was formed, the disconnection rate was 0%.

(Example 2)
This will be described with reference to FIG.
A biaxially stretched PET (polyethylene terephthalate) film was used as the resin substrate 1. The thickness of the resin base material was 100 μm. The total light transmittance of the resin base material 1 was 92%. The easy adhesion layer 3 mainly composed of polyester having a thickness of 100 nm was applied to the resin substrate 1 by in-line coating.

The adhesion layer 8 (nickel) was formed on one surface side of the resin base material (this is the upper surface side) by a DC magnetron sputtering method so as to have a thickness of 10 nm by roll-to-roll. At this time, the distance between the resin base material surface and the opposing nickel target surface was 100 mm, and the power density input to the target was 3.79 kW / m ² . Further, argon was used as the sputtering gas, and the flow rate was adjusted so that the pressure was 0.3 Pa.

Next, a metal layer (copper) was formed on the upper surface side of the adhesion layer in FIG. 1 by a DC magnetron sputtering method so as to have a thickness of approximately 1 μm by roll-to-roll. At this time, the distance between the surface of the copper target facing the resin substrate was 100 mm, and the power density supplied to the target was 3.79 kW / m ² . Further, argon was used as the sputtering gas, and the flow rate was adjusted so that the pressure was 0.3 Pa.

  The thickness of the obtained adhesion layer was 10 nm, the thickness of the metal layer was 1.02 μm, and the total stress of the metal layer was −26 N / m.

The residual strain of the obtained metal layer was −8.4 × 10 ⁻⁴ .

The adhesion strength of the obtained laminate was No. When the tape of 405 is used, it is classified as 0 (no peeling on any grid). When 756 tape was used, it was also classified as 0.
When a predetermined pattern was formed, the disconnection rate was 2%.

(Example 3)
Fabrication and evaluation were performed in the same manner as in Example 2 except that the thickness of the metal layer 4 was aimed at 2 μm. The measurement and evaluation results are shown in Table 1 together with other examples and comparative examples.

Example 4
Production and evaluation were performed in the same manner as in Example 2 except that the thickness of the metal layer 4 was aimed at 0.5 μm. The measurement and evaluation results are shown in Table 1 together with other examples and comparative examples.

(Example 5)
Fabrication and evaluation were performed in the same manner as in Example 2 except that the thickness of the metal layer 4 was aimed at 0.1 μm. The measurement and evaluation results are shown in Table 1 together with other examples and comparative examples.

(Example 6)
A biaxially stretched PET (polyethylene terephthalate) film was used as the resin substrate 1. The thickness of the base material was 98 μm. The total light transmittance of the resin base material 1 was 92%. The easy adhesion layer 3 mainly composed of polyester having a thickness of 190 nm was applied to the resin substrate 1 by in-line coating. Except for the resin substrate 1, it was produced and evaluated in the same manner as in Example 2. The measurement and evaluation results are shown in Table 1 together with other examples and comparative examples.

(Example 7)
A biaxially stretched PET film (trade name: “Lumirror” (registered trademark) T60) was used as the resin substrate 1. The thickness of the resin base material was 100 μm. The total light transmittance of the resin base material 1 was 91%. After the formation of the adhesion layer, the same procedure as in Example 2 was performed.

  The measurement and evaluation results are shown in Table 1.

(Example 8)
A biaxially stretched PET (polyethylene terephthalate) film was used as the resin substrate 1. The thickness of the resin substrate 1 was 100 μm. The total light transmittance of the resin base material 1 was 92%. The easy adhesion layer 3 mainly composed of polyester having a thickness of 100 nm was applied to the resin substrate 1 by in-line coating.

The adhesion layer 8 (nickel) was formed on one surface side of the resin base material (this is the upper surface side) by a DC magnetron sputtering method so as to have a thickness of 10 nm by roll-to-roll. At this time, the distance between the resin base material surface and the opposing nickel target surface was 100 mm, and the power density input to the target was 3.79 kW / m ² . Further, argon was used as the sputtering gas, and the flow rate was adjusted so that the pressure was 0.3 Pa. The distance between the crucible surface of the vapor deposition source and the cooling drum surface holding the resin substrate was 400 mm, and the pressure in the chamber was 0.02 Pa.

  Next, a metal layer (copper) was formed by roll-to-roll on the upper surface side of the adhesion layer in FIG. 1 by an electron beam low vacuum deposition method so that the thickness was approximately 1 μm. As a result of introducing nitrogen gas at 2.0 L / min to bring the inside of the chamber into a low vacuum state, the pressure in the chamber was 0.15 Pa. The distance between the crucible surface of the vapor deposition source and the cooling drum surface holding the resin base material was 400 mm.

  The measurement and evaluation results are shown in Table 1.

(Comparative Example 1)
A biaxially stretched PET (polyethylene terephthalate) film was used as the resin substrate 1. The thickness of the substrate was 100 μm. The total light transmittance of the resin base material 1 was 92%. The easy adhesion layer 3 mainly composed of polyester having a thickness of 100 nm was applied to the resin substrate 1 by in-line coating.

  A metal layer 4 (copper) was formed by roll-to-roll on one surface side of the resin base material (this is the upper surface side) by an electron beam vacuum deposition method so that the thickness was approximately 1 μm. . The output of the electron gun was 53.5 kW / m with respect to the film forming width. The distance between the crucible surface of the vapor deposition source and the cooling drum surface holding the resin substrate was 400 mm, and the pressure in the chamber was 0.02 Pa.

  The measurement and evaluation results are shown in Table 1.

(Comparative Example 2)
This will be described with reference to FIG.
A biaxially stretched PET (polyethylene terephthalate) film was used as the resin substrate 1. The thickness of the resin base material was 100 μm. The total light transmittance of the resin base material 1 was 92%. The easy adhesion layer 3 mainly composed of polyester having a thickness of 100 nm was applied to the resin substrate 1 by in-line coating.

The adhesion layer 8 (nickel) was formed on one surface side of the resin base material (this is the upper surface side) by a DC magnetron sputtering method so as to have a thickness of 10 nm by roll-to-roll. At this time, the distance between the resin base material surface and the opposing nickel target surface was 100 mm, and the power density input to the target was 3.79 kW / m ² . Further, argon was used as the sputtering gas, and the flow rate was adjusted so that the pressure was 0.3 Pa.

  Thereafter, in the same manner as in Comparative Example 1, the metal layer 4 was formed by vacuum deposition so that the thickness was approximately 1 μm.

  The measurement and evaluation results are shown in Table 1.

(Comparative Example 3)
Comparative Example 2 was performed except that the thickness of the metal layer was aimed at 0.5 μm. The measurement and evaluation results are shown in Table 1.

From the comparison between Example 1 and Comparative Example 1 and the comparison between Examples 2-8 and Comparative Examples 2-3, the total stress of the metal layer is −250 N / m or more and 0 or less, or the residual strain is −3. It turns out that it is a big effect with respect to a disconnection rate that it is * 10 < ^-3 > or more and -1 * 10 < ^-4 > or less.

  The present invention is suitable for manufacturing a laminate that is a raw material for forming a wiring circuit by a subtractive method that is less expensive than the semi-additive method. In particular, when applied to a roll-to-roll process where the resin substrate surface is often touched with a roll during transport, the resin substrate surface is susceptible to scratches from submicron to several microns in depth. Since the possibility of inducing is high, the effect of the present invention appears remarkably.

1: Resin base material 2: Scratch 3: Easy adhesion layer 4: Metal layer 5: Stress direction of metal layer 6: Scratch edge portion 7: Crack 8: Adhesion layer 21: Line portion 22: Space portion 23: Electrode pad 31: Plane 32: Arrow height of arc 33: Chord length of arc

Claims (5)

A laminate for a circuit, comprising a metal layer on at least one side of a resin base material, wherein the total stress of the metal layer is −250 N / m or more and 0 N / m or less. A laminate for a circuit having a metal layer on at least one surface of a resin base material, wherein the residual strain of the metal layer is -3 × 10 ⁻³ or more and −1 × 10 ⁻⁴ or less. The circuit laminate according to claim 1, further comprising an easy-adhesion layer on at least one side of the resin base material. The thickness of the said easily bonding layer is 10 nm or more and 300 nm or less, The laminated body for circuits of Claim 3 characterized by the above-mentioned. The thickness of the said metal layer is 0.05 micrometer or more and 10 micrometers or less, The laminated body for circuits in any one of Claims 1-4 characterized by the above-mentioned.

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