Abstract:
It is an major object to ravel out the drawbacks that it is difficult to form a sectional shape of a metal pattern in square and it is also difficult to obtain a constant line width in the conventional full additive method and semi additive method, and to solve the problem that it is difficult to secure dimensional accuracy and positional accuracy at a high level in the above method using conductive ink and a photoresist since this method is carried out by utilizing printing. To attain the above object, in the present invention, a conductive pattern  12   a  is obtained by forming concavo-convex on a substrate  1  by using a pattern substrate  4 , and forming a conductive thin layer  9 , then coating with a layer  10  of a photosensitive resin, exposing and developing by using the pattern substrate  4  again to bare a conductive thin layer  9   a  on the convex portion and carrying out electrolytic plating. The conductive thin layer  9  and the layer of the photosensitive resin on the concave portion may be removed.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a method for manufacturing a substrate having a conductive pattern, the method capable of forming a conductive pattern selectively on a concave portion or a convex portion by forming desired pattern-wise concavo-convex on the surface of a substrate.  
           [0003]    2. Description of the Related Art  
           [0004]    In order to form a metal conductive pattern on the surface of a substrate, there is a subtractive method in which first, a metal layer is provided on the entire surface, a photoresist layer is laminated thereon, resist pattern is formed by pattern exposing and developing, and then etched. By this subtractive method, since the most of the metal layer once formed is generally removed, giving rise to a problem as to the recovery of the metal, and also arousing the necessity for treating a large amount of etching effluent.  
           [0005]    There are also a full-additive method in which a plating resist pattern is provided on a surface of a substrate, and a metal pattern is provided by electroless plating on the exposed portion which is not coated with the plating resist pattern, or a semi-additive method in which a plating resist pattern is provided on a metal layer provided by electroless plating on the surface of a substrate or the like, and a metal pattern is provided by electrolytic plating on the exposed portion which is not coated with the plating resist pattern. Because a metal layer can be provided pattern-wise on necessary places in these full-additive method and semi-additive method, the drawbacks of the aforementioned subtractive method are eliminated.  
           [0006]    However, in these full-additive method and semi-additive method, although the metal pattern is determined by the shape of an opening portion of the plating resist pattern, it grows by plating so that these methods have the drawbacks that it is difficult to form a square sectional shape and it is also difficult to obtain a constant line width.  
           [0007]    In Japanese Patent Application Laid-Open (JP-A) No. 2000-265087, a method is described in which a pattern is printed by conductive ink on a transparent base material, coated with a negative type photoresist layer thicker than the film thickness of the pattern, exposed to light from the backside of the base material, developed to remove the photoresist layer on the pattern, and then a metal pattern is formed on the pattern by electrolytic plating. In this method, however, since the first pattern is formed by printing, it is difficult to secure dimensional accuracy and positional accuracy at a high level.  
         SUMMARY OF THE INVENTION  
         [0008]    An object of the present invention is to ravel out the drawbacks that it is difficult to form a metal pattern in a square sectional shape and it is also difficult to obtain a constant line width in the conventional full-additive method and semi-additive method, and to solve the problem that it is difficult to secure dimensional accuracy and positional accuracy at a high level in the above method using conductive ink and a photoresist since this method is carried out by printing.  
           [0009]    The above object can be achieved by the following processes. As shown schematically in FIG. 5, instead of the formation of a plating resist pattern and the formation of a conductive ink pattern in the conventional method, a concavo-convex layer  7  which is a cured curing resin composition  5  was formed on a substrate  1  by using a pattern substrate  4  (concavo-convex type). After forming a conductive thin layer  9  on the entire surface by vapor deposition or the like, the whole surface was coated with a layer of the photosensitive resin  10 , and exposed using the pattern substrate  4  as a light shielding pattern substrate  11 , for example, the conductive thin layer  9   a  on the convex portion is selectively exposed, and the bared conductive thin layer  9   a  was plated. Whereby a conductive pattern substrate  13   a  having a conductive pattern  12   a  with a good sectional shape and a line width can be obtained.  
           [0010]    The first invention relates to a method for manufacturing a conductive pattern substrate wherein each following processes (1) to (4) are carried out in sequence: (1) a process of forming a concavo-convex layer, on a substrate A, formed of a cured product of a curing resin composition, and comprising a concave portion corresponding to portions with a light shielding layer of a pattern layer and a convex portion corresponding to portions without the light shielding layer, by laminating a substrate A on a pattern substrate C, on which a pattern layer constituted of parts with layer laminated and parts without layer laminated on another substrate B, via the curing resin composition such that the pattern layer is facing the substrate A, then cure the curing resin composition between the substrate A and the pattern substrate C, and peeling the pattern substrate C after curing, (2) a process of forming a conductive thin layer on the concavo-convex layer by a gas phase method on the bottom of the concave portion of the concavo-convex layer and on the top of the convex portion of the concavo-convex layer, (3) a process of laminating a photosensitive resin composition layer on the entire surface of the thin layer formed on the concavo-convex layer such that the concavo-convex derives from the concavo-convex layer is flattened, exposing the laminated photosensitive resin composition layer via a light shielding pattern substrate D having the same pattern of the light shielding pattern as the pattern layer of the pattern substrate C, and developing after the exposure to remove the photosensitive resin composition layer laminated on either of the bottom of the concave portion or the top of the convex portion, thereby baring the conductive thin layer and (4) a process of forming a conductive pattern by plating the bared layer of the conductive thin layer with a metal.  
           [0011]    The second invention relates to a method for manufacturing a conductive pattern substrate according to the first invention, wherein the photosensitive resin composition is a positive type, and after conducting (4) the process of forming a conductive pattern, (5) a process of exposing the entire surface of the photosensitive resin composition layer, and carrying out etching after the exposure of the entire surface to remove the photosensitive resin composition layer on the conductive thin layer of the concave portion, is conducted.  
           [0012]    The third invention relates to a method for manufacturing a conductive pattern substrate according to the second invention, wherein in the process (5), the conductive thin layer on the concave portion is also removed in addition to the removal of the photosensitive resin composition layer on the concave portion.  
           [0013]    The fourth invention relates to a method for manufacturing a conductive pattern substrate according to the first invention, wherein the photosensitive resin composition is a negative type, and after conducting (4) the process of forming a conductive pattern, (5′) a process of carrying out etching to remove the photosensitive resin composition layer on the conductive thin layer of the convex portion, is conducted.  
           [0014]    The fifth invention relates to a method for manufacturing a conductive pattern substrate according to the fourth invention, wherein in the process (5′), the conductive thin layer on the convex portion is also removed in addition to the removal of the photosensitive resin composition layer on the convex portion.  
           [0015]    According to the first invention, the formation of concavo-convex and the selective removal, of the conductive thin layer formed on the concavo-convex, are carried out by using pattern having the same plane shape. Therefore, the pattern of the conductive thin layer, which is a base when the conductive pattern is formed, is well reproduced to the pattern substrate. Therefore, a method for manufacturing a conductive pattern substrate capable of forming a highly precise conductive pattern can be provided.  
           [0016]    According to the second invention, in addition to the effect of the first invention, since the photosensitive resin composition is a positive type, the photosensitive resin composition on the convex portion and on the concave portion is solubilized by exposure so that it is easy to remove selectively. Therefore, a method for manufacturing a conductive pattern substrate capable of forming highly precise conductive pattern only on the convex portion can be provided.  
           [0017]    According to the third invention, in addition to the effect of the second invention, a method for manufacturing a conductive pattern substrate can be provided, wherein the conductive thin layer on the bottom of the concave portion is also removable.  
           [0018]    According to the fourth invention, in addition to the effect of the first invention, since the photosensitive resin composition is a negative type, a method for manufacturing a conductive pattern substrate can be provided, wherein an unexposed photosensitive resin composition on the concave portion can be removed selectively with ease, so that a highly precise conductive pattern can be formed only on the concave portion.  
           [0019]    According to the fifth invention, in addition to the effect of the fourth invention, a method for manufacturing a conductive pattern substrate can be provided wherein the conductive thin layer on the top of the convex portion can also be removed. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]    [0020]FIG. 1 is a view showing a process for manufacturing a substrate, a pattern substrate and a concavo-convex laminated body.  
         [0021]    [0021]FIG. 2 is a view showing a process of forming a conductive thin layer and a process of laminating and exposing a photosensitive resin composition layer.  
         [0022]    [0022]FIG. 3 is a view showing a process of forming a conductive pattern in the case of using a positive type photosensitive resin.  
         [0023]    [0023]FIG. 4 is a view showing a process of forming a conductive pattern in the case of using a negative type photosensitive resin.  
         [0024]    [0024]FIG. 5 is a view showing the outline of a manufacturing method in the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0025]    All of FIGS.  1  to  4  are views showing each process in a method of manufacturing a substrate having a conductive pattern of the present invention. As will be mentioned later, the order of the processes shown in the figures is roughly classified into two types depending on the type of photosensitive resin composition to be used, namely, the order of FIG. 1→FIG. 2→FIG. 3 and the order of FIG. 1→FIG. 2→FIG. 4.  
         [0026]    First, a substrate A (symbol  1  in the figures) is prepared. The substrate A constitutes a circuit substrate and the like, and specifically formed from an inorganic base material such as glass, a silicon wafer or quartz, or an organic base material such as those exemplified in the following. Examples of the organic base material may include a polyamide, polyacetal, polybutylene terephthalate, polyethylene terephthalate, polyethylene naphthalate, or syndiotactic polystyrene or the like, polyphenylene sulfide, polyether ether ketone, a liquid crystal polymer, fluorine resin, or polyether nitrile, polycarbonate, denatured polyphenylene ether, polycyclohexene, or polynorbornane type resin, or the like, or polysulfone, polyether sulfone, polyarylate, polyamideimide, polyether imide, or thermoplastic polyimide. Base materials made of typical plastics may also be used. Particularly, in the case where the substrate A is an organic base material, the use of a thin flexible film formed material having a thickness about 5 μcm to 300 μm is desirable because the resulting substrate having a conductive pattern can be made flexible.  
         [0027]    Next, a pattern substrate C (symbol  4  in the figures), on which a pattern layer P (symbol  3  in the figures) is laminated on a substrate B (symbol  2  in the figures) which is different from the substrate A, is prepared. A raw material constituting the substrate B is principally the same as that constituting the substrate A. However, as will be mentioned later, because the pattern substrate C is used as a mask pattern when exposing a photosensitive resin composition layer, the substrate B is preferably transparent to exposing light. Although the thickness of the substrate B is unprescribed, the substrate is preferably thicker from the viewpoint of dimensional stability. The thickness of the substrate B is about 1 mm to 5 mm if the substrate B is made of glass or quartz among the aforementioned inorganic base materials, and about 50 μm to 300 μm if the substrate B is made of the aforementioned organic base material.  
         [0028]    The pattern layer P is constituted from a patterned light shielding layer. The light shielding layer may be either of a thin film layer of an inorganic material such as chromium, or a layer of a resin composition containing a light shielding agent such as a dye and a pigment. When the pattern layer P is constituted of the presence and absence of a thin film layer of an inorganic material such as chromium, the formation of the pattern layer P may be carried out by using the same photoetching method that is used for manufacturing a photomask for manufacturing a semiconductor. Or the formation of the pattern layer P may also be carried out by using a method of subjecting pattern exposure and developing to a photosensitive resin layer formed on a base material by coating or lamination.  
         [0029]    In this case, the pattern layer P is constituted of a part where the light shielding layer is present and a part where the light shielding layer is not present. When a layer of a photosensitive resin used afterwards is a positive type, the pattern layer P is structured such that the part where the light shielding layer is not present has a conductive pattern shape. Supposing that the pattern substrate C only serves as a mask pattern substrate, the thickness of the light shielding layer may be very thin. However, in the pattern substrate C used in the present invention, the thickness of the light shielding layer determines the depth of the concave portion of the concavo-convex layer to be formed on the substrate A, and the thickness of the light shielding layer is therefore preferably about 10 nm to 1 μm although it depends on a substrate having a conductive pattern to be intended. The widths of the part where the light shielding layer is present and the part where the light shielding layer is not present are also preferably 10 nm to 1 μm, same as the thickness. Also, the sectional shape of each part of the pattern layer P is preferably as close to square as possible. Even if the corner portion of the sectional shape is rounded, the curvature radius r of the round corner is preferably {fraction (1/10)} or less of the thickness of the light shielding layer.  
         [0030]    The reason why the pattern layer P is constituted of the presence and absence of the light shielding layer is that the pattern substrate C is also used when the photosensitive resin composition is subjected to pattern exposure in the subsequent process. However, if the pattern substrate C is only used when deciding the depth of the concave portion of the concavo-convex layer formed on the substrate A, and if a different pattern substrate is used in the subsequent pattern exposure of the photosensitive resin composition, the pattern layer P may be constituted of a light transmitting layer, not of a light shielding layer. If the pattern layer P is constituted of a light transmitting layer, light is transmitted through the pattern layer P when exposed from the substrate B side of the pattern substrate C, and it is therefore possible to cure the curing resin placed in between the substrate A and the pattern substrate C by irradiating light from the pattern substrate C side.  
         [0031]    The substrate A and the pattern substrate C are laminated on each other such that the pattern layer P is on the substrate A side, and also the curing resin composition  4  is interposed between the both. The material to be sandwiched in between the both is not necessarily to be a curing resin composition. However, it is preferable to use a curing resin composition having high heat resistance and other durability in consideration of the heat to be applied when a metal thin layer is formed in the subsequent process and the use of a substrate having a conductive pattern.  
         [0032]    Given as examples of the above curing resin composition are a curing resin by itself, or mixtures of curing resins such as an unsaturated polyester, melamine, epoxy, polyester (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, polyether (meth) acrylate, polyol (meth) acrylate, melamine (meth) acrylate, triazine type acrylate, and the like. A curing agent, a photo polymerization initiator, and the like may be added to these curing resin compositions according to the need. These curing resin compositions may be used as curing resin compositions of thermosetting resin compositions or ionizing radiation curing resin compositions such as ultraviolet curing resin compositions or the like. The curing resin composition preferably has a viscosity suitable for coating and it is preferable to adjust the viscosity by compounding a solvent or a monomer.  
         [0033]    The lamination of the substrate A and the pattern substrate C via the curing resin composition  4  can be carried out by coating the curing resin composition on either or both of the surface of the substrate A and the surface of the pattern layer P side of the pattern substrate C and laminating on each other, or fixing the both with a space, in advance, and then injecting the curing resin composition in between them.  
         [0034]    After laminating the substrate A and the pattern substrate C via the curing resin composition, the curing resin composition interposed between the both is cured. When the thermosetting resin composition is used, it is cured by allowing it to stand for the time required at normal temperature or under heating, or when an ionizing radiation curing resin composition such as ultraviolet ray curing resin composition is used, it is cured by irradiating with ionizing radiation such as ultraviolet rays  6 . When the curing is carried out by irradiating ionizing radiation, the radiation is irradiated from the ionizing radiation transmitting substrate side among the substrate A and the pattern substrate C. Therefore, in the case where the substrate A is constituted of an ionizing radiation transmitting raw material and ultraviolet rays are irradiated, it is constituted of a transparent material, or when the substrate B constituting the pattern substrate C and the pattern layer P are constituted of an ionizing radiation transmitting raw material and ultraviolet rays are irradiated, the both are constituted of a transparent material. If electron rays are irradiated, since the penetrability of electron rays is relatively high, transparency is not necessary required and it is not limited as long as it transmits electron ray.  
         [0035]    After curing the curing resin composition interposed between the substrate A and the pattern substrate C, the pattern substrate C is peeled off to thereby obtain an concavo-convex laminated body  8  in which a concavo-convex layer  7 , constituted of a convex portion  7   a  corresponding to the portion of the pattern layer P where the light shielding layer is not present, and a concave portion  7   b  corresponding to the portion of the pattern layer P where the light shielding layer is present and which is constituted of the cured product of the curing resin composition is laminated on the substrate A. The concavo-convex layer  7 , as shown in FIG. 3, may be one continuous layer as a whole, with thin concave portion, or there may be no cured product of the curing resin composition in the concave portion  7   b . In the latter case, the total thickness of the concavo-convex layer  7  is about 10 nm to 1 μm which is the thickness of the light shielding layer, and in the former case, the total thickness of the concavo-convex layer  7  is about 100 nm to 10 μm.  
         [0036]    As shown in FIG. 2A, on the concavo-convex layer  7  of the concavo-convex laminated body  8 , by a gas phase method such as a vapor deposition method or sputtering method, conductive thin layers  9   a  and  9   b  are respectively formed on the bottom of the concave portion  7   b  and on the top of the convex portion  7   a . By gas phase method, since a raw material used to form a thin layer adheres in a more orientating manner as compared with a liquid phase method such as plating, the conductive thin layer  9  is not substantially formed on the side surface of the convex portion  7   a.    
         [0037]    As the raw material constituting the conductive thin layer  9 , a high conductive material such as Fe, Ni, Cr, Cu, Ti, Hf, Zn, Zr, Mo, Ta, or the like is desirable. The conductive thin layer  9  may either be constituted of a single layer made of the same metal, or it may be constituted of two or more layers comprising metals differing from each other. For example, a highly adhesive thin layer of Cr is formed on the concavo-convex layer  7  made of the cured product of the photosensitive resin composition, and then a thin layer of Cu is formed. The thickness of the conductive thin film  9  constituted of the above metals is preferably about 20 nm to 500 nm.  
         [0038]    A photosensitive resin composition layer  10  is laminated on the entire surface of the concavo-convex layer  7 , on which the conductive thin layer  9  is formed, so as to flatten the concavo-convex derived from the concavo-convex layer  7 . In order to flatten the concavo-convex, it is only required to make the thickness of the photosensitive resin composition layer  10  higher than the height of the convex portion (difference in altitude between the convex portion and the concave portion). Accordingly, the thickness of the photosensitive resin composition layer  10  is preferably about 10 nm to 20 μm.  
         [0039]    Examples of the photosensitive resin composition include a positive type photosensitive resin, for example, a photolysis soluble type quinonediazide type photosensitive resin as a major component, or a negative type photosensitive resin comprising, for example, a photolysis crosslinking type azide type photosensitive resin, photolysis insoluble type diazo type photosensitive resin, photo dimerization type cinnamate type photosensitive resin, photo polymerization type unsaturated polyester type photosensitive resin, photo polymerization type acrylate resin or cationic polymerization type resin as a component. In addition to these photosensitive resin compositions, a photo polymerization initiator, sensitizing dyes and the like are accompanied, as needed.  
         [0040]    The laminated photosensitive resin composition layer  10  is exposed via a light shielding pattern substrate D (symbol  11  in the figures) having the same plane shape shielding pattern as the pattern substrate C. It is preferable to use the pattern substrate C having a pattern layer constituted of a patterned light shielding layer, as the light shielding pattern substrate D. However, in this case, since the light shielding pattern substrate D is used for pattern exposure, not for the purpose of forming concavo-convex, thickness of the pattern layer P is not necessary required. Therefore, the light shielding pattern substrate D may be the one different from the pattern substrate C on which thin light shielding pattern layers are laminated, however, the one with the same plane shape pattern as the pattern substrate C is used. In any case, the substrate A and the light shielding pattern substrate D are aligned such that the horizontal positional relationship of the light shielding pattern substrate D, laminated on the photosensitive resin composition layer  10 , to the substrate A is the same as the positional relationship of the former pattern substrate C to the substrate A when the pattern substrate C is used.  
         [0041]    The exposure is carried out by irradiating with ultraviolet rays at 0.1 to 10,000 mJ/cm 2  and preferably 10 to 1,000 mJ/cm 2  using a light source such as an extra high pressure mercury lamp, high pressure mercury lamp, carbon arc, xenon arc or metal halide lamp or the like.  
         [0042]    The exposed part is solubilized by the exposure when the photosensitive resin composition layer  10  contains a positive type photosensitive resin as its major component. Therefore, by developing after the exposure, the solubilized part of the photosensitive resin composition layer on the convex portion  7   a  of the concavo-convex layer  7  is dissolved and removed by a developer. As a consequence, the conductive thin layer  9   a  formed on the top of the convex portion  7   a  is bared, and the conductive thin layer  9   b  formed on the bottom of the concave portion  7   b  remains coated with the photosensitive resin composition layer  10   b . By emphasizing the condition of development, the photosensitive resin composition layer  10   b  on the concave portion  7   b  may be made thinner compared with the original photosensitive resin composition layer  10 , and to be removed to an extent that the concave portion  7   b  is filled (FIG. 3A).  
         [0043]    The exposed part is insolubilized by the above exposure when the photosensitive resin composition layer  10  contains a negative type photosensitive resin as its major component. Therefore, by developing after the exposure, the part of the photosensitive resin composition layer  10  on the concave portion  7   b  of the concavo-convex layer  7 , which is not insolubilized, is dissolved and removed by a developer. As a consequence, the conductive thin layer  9   b  formed on the bottom of the concave portion  7   b  is bared and the conductive thin layer  9   a  formed on the top of the convex portion  7   a  remains coated with the insolubilized photosensitive resin composition layer  10   a.    
         [0044]    The conductive thin layer  9   b  on the top of the convex portion and the conductive thin layer  9   b  on the bottom of the concave portion, which are bared by the exposure and developing of the photosensitive resin composition layer  10 , are subjected to electrolyticmetal plating to form a conductive pattern  12   a  (FIG. 3B) or  12   b  (FIG. 4B).  
         [0045]    The metal used to constitute the conductive patterns  12   a  and  12   b  is basically the same as those exemplified as the raw material constituting the conductive thin layer  9 , Cu which has high conductivity is preferable, or may be gold, silver or the like. The thickness of the conductive patterns  12   a  and  12   b  is preferably 100 nm to 20 μm and more preferably about 1 μm to 10 μm though it depends on the line width or the degree of conductivity required.  
         [0046]    As shown in FIG. 4B, when the conductive thin layer  9   b  on the bottom of the concave portion  7   b  is plated with metal to form the conductive pattern  12   b , the conductive thin layer  9   a  on the top of the convex portion  7   a  and the insolubilized photosensitive resin composition layer  10   a  on the conductive thin layer  9   a  are remained. In the case where the conductive thin layer  9   a  is not necessary, the photosensitive resin composition layer  10   a  and the conductive thin layer  9   a  are etched one by one by changing an etching solution, or etched by using an etching solution capable of removing the both, whereby a conductive pattern substrate  13   b , from which the conductive thin layer  9   a  on the top of the convex portion  7   a  and the photosensitive resin composition layer  10   a  are removed, can be obtained (FIG. 4C). When removing the conductive thin film  9   a  on the top of the convex portion  7   a  and the photosensitive resin composition layer  10   a , the conductive pattern  12   b  is also affected, and therefore the conductive pattern  12   b  possibly becomes thinner than when it is formed. The thickness of the aforementioned conductive pattern  12   b  is preferably determined by calculating backwards from the thickness required for the final conductive pattern substrate  13   b , considering that the conductive pattern becomes thinner as mentioned above.  
         [0047]    As shown in FIG. 3B, when forming the conductive pattern  12   a  by plating metal to the conductive thin layer  9   b  on the convex portion  7   a , the conductive thin film layer  9   b  and the photosensitive resin composition layer  10   b , which is difficult to be dissolved and removed as it is, are laminated on the bottom of the concave portion  7   b . Therefore, in order to remove the both in the case where these are not necessary, first, exposure is carried out, from the side on which the photosensitive resin composition layer  10   b  is laminated, to solubilize the photosensitive resin composition layer  10   b  (FIG. 3C). Then the solubilized photosensitive resin composition layer  10   b  and the conductive thin layer  9   b  are etched one by one by changing an etching solution, or etched by using an etching solution capable of removing the both, whereby a conductive pattern substrate  13   a  (FIG. 3D), from which the conductive thin layer  9   b  and the photosensitive resin composition layer  10   b  on the bottom of the concave portion  7   b  are removed can be obtained. In this case, the conductive pattern  12   a  is also affected and possibly becomes thinner. Therefore, the thickness of the aforementioned conductive pattern  12   a  is preferably determined by calculating backwards from the thickness required for the final conductive pattern substrate  13   a.    
         [0048]    When the conductive pattern  12   a  is formed on the convex portion  7   a  as shown in FIGS. 4A and 4B, the conductive thin layer  9   b  remains on the bottom of the concave portion  7   b , whereas when the conductive pattern  12   b  is formed on the concave portion  7   b , the conductive thin layer  9   a  remains on the top of the convex portion  7   a . This may be used as a conductive pattern substrate, as it is. However, because a little of the conductive thin layer possibly adheres also to the side surface of the convex portion  7   a  when the conductive thin film is formed in the previous process. Since there is a risk that the conductive thin layer  9   a  on the top of the convex portion  7   a  is electrically conducted to the conductive thin layer  9   b  on the bottom of the concave portion  7   b , it is desired to remove the conductive thin layer on the side surface of the convex portion  7   a , which is very thin if produced, by carrying out etching for a short time.  
       EXAMPLES  
     Example 1  
       [0049]    A Cr thin film layer of 300 nm thickness is formed on a glass substrate by a photoetching method, in a pattern of fine lines having a line width of 500 nm with a pitch of 1 μm, to make a pattern substrate for forming concavo-convex. An uncured transparent ultraviolet curing resin was sandwiched and laminated in between the pattern side of this pattern substrate for forming concavo-convex and a polycarbonate film of 100 μm in thickness. The above was exposed from the polycarbonate film side to cure the ultraviolet curing resin. Then by peeling the pattern substrate for forming concavo-convex, a concavo-convex pattern, whose width of the convex portion and the width of the concave portion was 500 nm and the height difference between the convex portion and the concave portion was 300 nm, that the concavo-convex of the pattern substrate for forming concavo-convex is transferred to the polycarbonate film, is formed.  
         [0050]    On the resulting concavo-convex pattern, a Cu thin layer was formed on the top of the convex portion and the bottom of the concave portion in the concavo-convex pattern by sputtering method such that the thickness of the Cu thin layer was 100 nm. Then, the concavo-convex pattern was coated with a positive type photosensitive resin composition (trade name; “PMER P-LA900”, manufactured by Tokyo Ohka Kogyo Co., Ltd.) by a spinner, heated at 80° C. for 30 minutes to form a layer of the positive type photosensitive resin composition having a thickness of 8 μm and a flat upper surface.  
         [0051]    On the layer of the positive type photosensitive resin composition, the pattern substrate for forming concavo-convex first used was aligned so as the pattern side is in contact with the layer of the positive type photosensitive resin composition, and also aligned with the same position on the polycarbonate film as that of when forming the concavo-convex pattern, was brought into close contact, and was exposed to ultraviolet rays from the glass substrate side of the pattern substrate for forming concavo-convex. After the exposure, developing was carried out using a developer (trade name; “PMER Dev P-7G”, manufactured by Tokyo Ohka Kogyo Co., Ltd.) to remove the solubilized part which was the exposed part of the positive type photosensitive resin composition on the convex portion, thereby baring the thin layer of Cu on the convex portion. Utilizing this thin layer, electrolytic plating was carried out by using a copper sulfate plating bath to form a Cu plating layer of 3 μm thickness on the convex portion.  
         [0052]    Thereafter, the side on which the Cu plating layer was formed was exposed to ultraviolet rays to solubilize the layer of the positive type photosensitive resin composition remaining in the concave portion, and the solubilized layer of the positive type photosensitive resin composition in the concave portion was removed by using a developer (trade name; “PMER Dev P-7G”, manufactured by Tokyo Ohka Kogyo Co., Ltd.). Then, the resulting substrate was further dipped in an aqueous sodium persulfate solution (sodium persulfate; 20 g and HCl; 10 ml were contained in 1000 cm 3 ) for 3 minutes and in an aqueous potassium permanganate solution (potassium permanganate; 50 g and NaOH; 30 g were contained in 1000 cm 3 ) for 4 minutes to remove the Cu thin film on the bottom of the concave portion, thereby obtaining a conductive pattern substrate.