Patent Publication Number: US-2012030938-A1

Title: Method of manufacturing printed circuit board

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a U.S. divisional application filed under 37 CFR 1.53(b) claiming priority benefit of U.S. patent application Ser. No. 12/285,871 filed in the United States on Oct. 15, 2008, which claims earlier priority benefit to Korean Patent Application No. 10-2008-0030831 filed with the Korean Intellectual Property Office on Apr. 2, 2008 and Korean Patent Application No. 10-2008-0076989 filed with the Korean Intellectual Property Office on Aug. 6, 2008, the disclosures of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Field 
     The present invention relates to a printed circuit board. 
     2. Description of the Related Art 
     With the development of the electronics industry, electronic components such as a portable device require high efficiency, high performance and miniaturization. Accordingly, studies are in progress to manufacture a printed circuit board for a high density surface mounted component, for example, a system in package (SIP) and a 3D package. 
     A conventional multi-layer circuit board for manufacturing a printed circuit board for a high density mounted component is manufactured through the steps of: processing a hole on a double-sided CCL (copper-clad laminate) by using a drill; plating the inside of the hole; forming a circuit pattern by etching the copper foil of both the upper and lower surfaces; interposing, heating and pressurizing prepreg, i.e., an insulating adhesive between many double-sided printed circuit boards having the circuit patterns; forming a hole at a predetermined position of the laminated multi-layer circuit board by using a drill; forming a plated layer inside the hole by plating the multi-layer circuit board so that an inner layer through is completed; and forming a desired circuit pattern by etching an outermost layer. 
     However, with the conventional manufacturing process of the multi-layer circuit board, it is difficult to reduce the thickness of the printed circuit board due to the complicated working process, difficulty of forming a fine pattern and the thick printed circuit board. 
     SUMMARY 
     The present invention provides a printed circuit board that can be made thin, are highly reliable, and can be manufactured with a short lead time, and a manufacturing method thereof. 
     An aspect of the present invention features a method of manufacturing a printed circuit board. The method in accordance with an embodiment of the present invention can include: providing a first resin layer having a first pattern on one surface thereof; forming a conductive bump on one surface of the first resin layer, the conductive bump being electrically connected to the first pattern; compressing an insulation layer and the first resin layer such that the conductive bump passes through the insulation layer; laminating a second resin layer on the insulation layer, the second resin layer having a second pattern on a surface thereof facing the insulation layer; and forming an opening by etching a part of at least one of the first resin layer and the second resin layer. 
     The forming of the opening can be performed through a laser etching method or a plasma etching method. 
     The method can further include forming a surface treatment layer in the opening, and forming a solder ball on the surface treatment layer. At least one of the first resin layer and the second resin layer can be made of a material including one of Liquid Crystal Polymer (LCP), Polyimide (PI), Polytetrafluoroethylene (PTFE) and Polyetheretherketon (PEEK). 
     Particularly, when at least one of the first resin layer and the second resin layer is made of a material including the Polyimide (PI), the insulation layer can be made of a material including Liquid Crystal Polymer (LCP). 
     Also, the first resin layer, the insulation layer and the second resin layer can be all made of a material including liquid crystal polymer. In this case, the insulation layer can have a lower melting point than those of the first resin layer and the second resin layer. 
     At least one of the first resin layer and the second resin layer can be a photo solder resist (PSR) and the forming of the opening can be performed by exposing the photo solder resist to light and developing the photo solder resist. 
     At least one of the first pattern and the second pattern can be formed by laminating a metal layer on one surface of the photo solder resist; forming a first photosensitive material layer on the metal layer; selectively exposing to light and developing the first photosensitive material layer; etching the metal layer; and removing the first photosensitive material layer. 
     The method can further include forming a second photosensitive material layer on the other surface of the photo solder resist, and further include removing the second photosensitive material layer before the forming of the opening. 
     The photo solder resist can further include a protective layer on the other surface thereof, and can further include removing the protective layer before the forming of the opening. In this case, the protective layer can be made of a material including polyethylene terephthalate (PET). The protective layer can be opaque. 
     Another aspect of the present invention features a printed circuit board. The printed circuit board in accordance with an embodiment of the present invention can include: an insulation layer; a first pattern buried in one surface of the insulation layer; a first resin layer laminated on one surface of the insulation layer to cover the first pattern; a second pattern buried in the other surface of the insulation layer; a via electrically connecting the first pattern to the second pattern; and a second resin layer laminated on the other surface of the insulation layer to cover the second pattern. 
     At least one of the first resin layer and the second resin layer is made of a material including one of Liquid Crystal Polymer (LCP), Polyimide (PI), Polytetrafluoroethylene (PTFE), Polyetheretherketon (PEEK) and photo solder resist (PSR). 
     Particularly, when at least one of the first resin layer and the second resin layer is made of a material including Polyimide (PI), the insulation layer can be made of a material including Liquid Crystal Polymer (LCP). 
     The first resin layer, the insulation layer and the second resin layer can be all made of a material including liquid crystal polymer. In this case, the insulation layer can have a lower melting point than those of the first resin layer and the second resin layer. 
     The via can be a bump formed by curing conductive paste. An opening can be formed on the first resin layer such that a part of the first pattern is exposed. In this case, a solder ball can be formed in the opening. 
     Yet another aspect of the present invention features a method of manufacturing a printed circuit board. The method of manufacturing printed circuit board in accordance with an embodiment of the present invention can include: providing a first resin layer having a first pattern on one surface thereof; forming a first conductive bump on the one surface of the first resin layer, the first conductive bump being electrically connected to the first pattern; interposing a first insulation layer and compressing one surface of the first resin layer and one surface of an inner layer substrate part; and forming an opening by etching a part of the first resin layer. 
     Also, the printed circuit board manufacturing method can further perform: providing a second resin layer having a second pattern on one surface thereof; forming a second conductive bump on the one surface of the second resin layer, the second conductive bump being electrically connected to the second pattern; interposing a second insulation layer and compressing one surface of the second resin layer and the other surface of the inner layer substrate part; and forming an opening by etching a part of the second resin layer. 
     The first resin layer can be made of a material including one of Liquid Crystal Polymer (LCP), Polyimide (PI), Polytetrafluoroethylene (PTFE) and Polyetheretherketon (PEEK). 
     Particularly, when the first resin layer is made of a material including Polyimide (PI), the first insulation layer can be made of a material including Liquid Crystal Polymer (LCP). 
     The first resin layer is a photo solder resist, and the forming of the opening can be performed by exposing the photo solder resist to light and developing the photo solder resist. 
     Here, the first pattern can be formed by laminating a metal layer on one surface of the photo solder resist; forming a photosensitive material layer on the metal layer; selectively exposing to light and developing the photosensitive material layer; etching the metal layer; and removing the photosensitive material layer. 
     The method can further include forming a second photosensitive material layer on the other surface of the photo solder resist, and further include removing the second photosensitive material layer before the forming of the opening. 
     The photo solder resist can further include a protective layer on the other surface thereof, and can further include removing the protective layer before the forming of the opening. In this case, the protective layer can be made of a material including polyethylene terephthalate (PET). The protective layer can be opaque. 
     Still another aspect of the present invention features a printed circuit board. The printed circuit board in accordance with an embodiment of the present invention can include: an inner layer substrate part; a first insulation layer laminated on one surface of the inner layer substrate part; a first pattern buried in one surface of the first insulation layer; a first resin layer laminated on one surface of the first insulation layer to cover the first pattern; and a first via electrically connecting the first pattern with the inner layer substrate part. The first resin layer is made of a material comprising one of Liquid Crystal Polymer (LCP), Polyimide (PI), Polytetrafluoroethylene (PTFE). Polyetheretherketon (PEEK) and a photo solder resist. 
     The printed circuit board can further include: a second insulation layer laminated on the other surface of the inner layer substrate part; a second pattern buried in the other surface of the second insulation layer; a second resin layer laminated on the other surface of the second insulation layer to cover the second pattern; and a second via electrically connecting the second pattern with the inner layer substrate part. 
     When the first resin layer is made of a material including Polyimide (PI), the first insulation layer can be made of a material including Liquid Crystal Polymer (LCP). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a flowchart showing a method of manufacturing a printed circuit board according to an embodiment of the present invention. 
         FIGS. 2 to 8  illustrate cross sectional views showing each process of a method of manufacturing a printed circuit board according to an embodiment of the present invention. 
         FIG. 9  illustrates a flowchart showing a method of manufacturing a printed circuit board according to another embodiment of the present invention. 
         FIGS. 10 to 16  illustrate cross sectional views showing each process of a method of manufacturing a printed circuit board according to another embodiment of the present invention. 
         FIG. 17  illustrates a flowchart showing a method of manufacturing a printed circuit board according to yet another embodiment of the present invention. 
         FIGS. 18 to 28  illustrate cross sectional views showing each process of a method of manufacturing a printed circuit board according to yet another embodiment of the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Since there can be a variety of permutations and embodiments of the present invention, certain embodiments will be illustrated and described with reference to the accompanying drawings. This, however, is by no means to restrict the present invention to certain embodiments, and shall be construed as including all permutations, equivalents and substitutes covered by the spirit and scope of the present invention. In the following description of the present invention, the detailed description of known technologies incorporated herein will be omitted when it may make the subject matter unclear. 
     Terms such as “first” and “second” can be used in describing various elements, but the above elements shall not be restricted to the above terms. The above terms are used only to distinguish one element from the other. 
     The terms used in the description are intended to describe certain embodiments only, and shall by no means restrict the present invention. Unless clearly used otherwise, expressions in the singular number include a plural meaning. In the present description, an expression such as “comprising” or “consisting of” is intended to designate a characteristic, a number, a step, an operation, an element, a part or combinations thereof, and shall not be construed to preclude any presence or possibility of one or more other characteristics, numbers, steps, operations, elements, parts or combinations thereof. 
     Hereinafter, certain embodiments of a printed circuit board and a manufacturing method thereof according to the present invention will be described in detail with reference to the accompanying drawings. Throughout the following description with reference to the accompanying drawings, identical or corresponding elements will be given the same reference numerals, and any redundant description of the identical or corresponding elements will not be repeated. 
       FIG. 1  illustrates a flowchart showing a method of manufacturing a printed circuit board according to an embodiment of the present invention.  FIGS. 2 to 8  illustrate cross section views showing each process of a method of manufacturing a printed circuit board according to an embodiment of the present invention. Illustrated in  FIGS. 2 to 8  are a first resin layer  10 , openings  11  and  21 , a first pattern  12 , a first pad  12   a,  surface treatment layers  13  and  23 , a conductive bump  34 , a second resin layer  20 , a second pattern  22 , a second pad  22   a,  an insulation layer  30  and a solder ball  40 . 
     First, as illustrated in  FIG. 2 , the first resin layer  10  having the first pattern  12  on one surface thereof is provided in the step represented by S 110 . In order to form the first pattern  12 , after either a substrate of resin coated copper (RCC) including the first resin layer  10  and a copper foil laminated on the first resin layer  10  or a substrate of flexible copper clad laminate (FCCL) is prepared, a part of the copper foil may be etched. It is also possible to plate the copper foil. 
     The main material of the first resin layer  10  can be any one of Liquid Crystal Polymer (LCP), Polyimide (PI), Polytetrafluoroethylene (PTFE) and Polyetheretherketon (PEEK). 
     Then, as illustrated in  FIG. 3 , after the conductive bump  34 , which is electrically connected to the first pattern  12 , is formed on one surface of the first resin layer  10  in the step represented by S 120 , the insulation layer  30  and the first resin layer  10  are compressed such that the conductive bump  34  passes through the insulation layer  30  in the step represented by S 130 . 
     The conductive bump  34  can be formed on a pad, which is a part of the first pattern  12 , and function as a via for an inner layer through by passing through the insulation layer  30 . Such a conductive bump  34  can be formed by printing a conductive material through a screen printing process or an ink jet printing process and then curing the printed conductive material. 
     The insulation layer  30  can be selectively used according to the kind of the first resin layer  10 . For example, if the main material of the first resin layer  10  is Polyimide (PI), liquid crystal polymer film can be used as the insulation layer  30 . If the main material of the first resin layer  10  is liquid crystal polymer (LCP), liquid crystal polymer film of the same kind with a melting point that is lower by as much as about 30° C. to 70° C. can be used as the insulation layer  30 . It is also possible that prepreg and ABF are used as the insulation layer  30 . 
     Then, as illustrated in  FIG. 5 , the second resin layer  20  having the second pattern  22  on the surface thereof facing the insulation layer  30  is laminated on the insulation layer  30  in the step represented by S 140 . The second pattern  22  and the upper part of the conductive bump  34  can be in contact with each other, and as a result the first pattern  12  can be electrically connected to the second pattern  22 . Like the first pattern  12 , the second pattern  22  can be also buried in the insulation layer  30 . 
     If prepreg and ABF are used as the insulation layer  30 , the main material of the second resin layer  20  can be any one of Liquid Crystal Polymer (LCP), Polyimide (PI), Polytetrafluoroethylene (PTFE) and Polyetheretherketon (PEEK), like the first resin layer  10 . If an LCP having a low melting point (between about 260° C. and 280° C.) is used as the insulation layer  30 , an LCP having a higher melting point by 30° C. to 50° C. than that of the insulation layer  30  can be used as the second resin layer  20 . 
     Subsequently, the openings  11  and  21  are formed by etching a part of at least one of the first resin layer  10  and the second resin layer  20  in the step represented by S 150 . A laser etching method and a plasma etching method, as well as various other methods, can be employed to form the openings  11  and  21 . As illustrated in  FIG. 6 , while the openings  11  and  21  are formed on both the first resin layer  10  and the second resin layer  20 , there can be various numbers and locations of the openings  11  and  21 , depending on the design. 
     Meanwhile, the first resin layer  10  and the second resin layer  20  are not entirely removed, and can function to protect the first pattern  12  and the second pattern  22 . That is, an existing solder resist can be substituted by the first resin layer  10  and the second resin layer  20 , thereby simplifying the process with no necessity of performing an extra process for forming the solder resist so that it is possible to remarkably reduce a lead time. 
     Then, as illustrated in  FIG. 7 , surface treatment layers  13  and  23  are formed on the pads  12   a  and  22   a,  which are exposed by the openings  11  and  21 , in the step represented by S 160 , and solder balls  40  are formed on the surface treatment layers  13  and  23  in the step represented by S 170 . Accordingly, it is possible to construct a structure that is capable of providing electrical connection to a mother board or an electronic element such as a semiconductor chip. In order to form the surface treatment layers  13  and  23 , nickel/gold plating, OSP processing, ENIG or ENEPIG, etc., can be used. 
     The printed circuit board manufactured as described above is illustrated in  FIG. 8 . The printed circuit board manufactured by the process described above can mainly include the insulation layer  30 , the first pattern  12 , which is buried in one surface of the insulation layer  30 , the first resin layer  10 , which is laminated on the one surface of the insulation layer  30  and configured to cover the first pattern  12 , the second pattern  22 , which is buried in the other surface of the insulation layer  30 , the via electrically connecting the first pattern  12  with the second pattern  22 , and the second resin layer  20 , which is laminated on the other surface of the insulation layer  30  and configured to cover the second pattern  22 . The main material of at least one of the first resin layer  10  and the second resin layer  20  can be any one of Liquid Crystal Polymer (LCP), Polyimide (PI), Polytetrafluoroethylene (PTFE) and Polyetheretherketon (PEEK). 
     While a printed circuit board according to a related art protects an outer layer by using a solder resist having a coefficient of thermal expansion of more than 50 ppm/° C., the printed circuit board according to this embodiment of the present invention presents a configuration which protects the pattern of the outer layer by using materials, such as Liquid Crystal Polymer (LCP), Polyimide (PI), Polytetrafluoroethylene (PTFE) and Polyetheretherketon (PEEK), which have relatively low coefficient of thermal expansion. 
     By substituting a conventional solder resist by a material having a low coefficient of thermal expansion, it is possible to the coefficient of thermal expansion can be reduced to between 1/2 and 1/10 times of the coefficient of thermal expansion of the conventional solder resist. 
     The thinner the printed circuit board becomes, the greater the ratio of the thickness of the solder resist protecting the pattern of the outer layer becomes. Thus, substitution of the conventional solder resist by a material having a low coefficient of thermal expansion can have a great significance in manufacturing the printed circuit board having a low coefficient of thermal expansion. 
     In addition, by implementing an inner layer connection using a conductive bump  34  as a via, which is formed by printing and curing the conductive paste, it is possible to simplify the manufacturing process, thereby reducing a lead time. 
     If the first resin layer  10 , the insulation layer  30  and the second resin layer  20  are all made of liquid crystal polymer, it is also possible to implement a thin printed circuit board that is highly dielectric. 
     Next, a method of manufacturing a printed circuit board according to another embodiment of the present invention will be described. 
       FIG. 9  illustrates a flowchart showing a method of manufacturing a printed circuit board manufacturing method according to another embodiment of the present invention.  FIGS. 10 to 16  illustrate cross section views showing each process of a method of manufacturing a printed circuit board according to another embodiment of the present invention. Illustrated in  FIGS. 10 to 16  are a first resin layer  10 , openings  11  and  21 , a first pattern  12 , a first pad  12   a , surface treatment layers  13  and  23 , a first conductive bump  34 , a second resin layer  20 , a second pattern  22 , a second pad  22   a,  a second conductive bump  24 , a first insulation layer  31 , a second insulation layer  32 , a solder ball  40 , an inner layer substrate part  50 , an inner layer circuits  51  and  53  and a via  52 . 
     The method of manufacturing the printed circuit board according to this embodiment differs from the manufacturing method of the embodiment described above in that the printed circuit board has more than two layers. Hereinafter, the difference from the embodiment described above will be described, and description of identical or corresponding elements will not be repeated. 
     First, as illustrated in  FIG. 10 , the first resin layer  10  having the first pattern  12  on one surface thereof is provided in the step represented by S 210 . As illustrated in  FIG. 11 , the first conductive bump  34 , which is electrically connected to the first pattern  12 , is formed on one surface of the first resin layer  10  in the step represented by S 220 . 
     Then, as illustrated in  FIG. 12 , the first insulation layer  31  is interposed, and becomes compressed by one surface of the first resin layer  10  and one surface of the inner layer substrate part  50 , in the step represented by S 230 . Subsequently, as illustrated in  FIG. 13 , the opening  11  is formed by etching a part of the first resin layer  10  in the step represented by S 240 . 
     The second resin layer  20  having the second pattern  22  on one surface thereof is provided in the step represented by S 250 , and the second conductive bump  24 , which is electrically connected to the second pattern  22 , is formed on one surface of the second resin layer  20  in the step represented by S 260 . Then, the second insulation layer  32  is interposed, and becomes compressed by one surface of the second resin layer  20  and the other surface of the inner layer substrate part  50 , in the step represented by S 270 . 
     Subsequently, the opening  21  can be formed by etching a part of the second resin layer  20  in the step represented by S 280 . 
     Thereafter, the solder ball  40  is formed in each of the openings  11  and  21 , constructing a structure capable of providing electrical connection to a mother board or an electronic element such as a semiconductor chip. 
     The printed circuit board manufactured through the above process is illustrated in  FIG. 15 . 
     With this embodiment, the inner layer substrate part  50  is located between the first resin layer  10  and the second resin layer  20 , unlike the earlier embodiment. By varying the configuration of the inner layer substrate part  50  and the number of layers, it is possible to manufacture a multi-layer printed circuit board of any number of layers. The inner layer substrate part  50  can accommodate the via  52  and inner layer circuits  51  and  53 . 
     While the first resin layer  10  and the second resin layer  20  are sequentially compressed with both sides of the inner layer substrate part  50  in  FIGS. 10 to 15 , it is also possible to collectively laminate the layers, as illustrated in  FIG. 16 . 
     In the following description, a method of manufacturing a printed circuit board according to yet another embodiment of the present invention will be described. 
       FIG. 17  illustrates a flowchart showing a method of manufacturing a printed circuit board according to yet another embodiment of the present invention.  FIGS. 18 to 28  illustrate cross sectional views showing each process of a method of manufacturing a printed circuit board according to yet another embodiment of the present invention. Illustrated in  FIGS. 18 to 28  are a first resin layer  10 , openings  11  and  21 , a metal layer  12 ′, a first pattern  12 , a first pad  12   a,  protective layers  15  and  25 , a first photosensitive material layer  26 , second photosensitive material layers  17  and  27 , a second resin layer  20 , a second pattern  22 , a second pad  22   a,  an insulation layer  30 , a conductive bump  34  and a solder ball  40 . 
     The embodiment of the present invention features that at least one of the first resin layer  10  and the second resin layer  20  is a photo solder resist. 
     First, the first resin layer  10  having the first pattern  12  is formed on one surface thereof in the step represented by S 310 . A subtractive method can be used in order to form the first pattern  12 . 
     As illustrated in  FIG. 18 , the metal layer  12 ′ is laminated on one surface of the first resin layer  10 , which has the protective layer  15  formed on the other surface thereof, in the step represented by S 311 . Since the metal layer  12 ′ is etched to become a circuit pattern of the printed circuit board, a conductive material, such as copper (Cu) or gold (Au), can be used. 
     The protective layer  15  is later removed when the manufacturing of a substrate is completed and is not absolutely necessary. However, by using the photo solder resist, on which the protective layer  15  is formed on the other surface thereof, the process of forming a substrate can be much more stable because the protective layer functions similar to a carrier so as to protect the photo solder resist. 
     The protective layer  15  can be made of a material including polyethylene terephthalate (PET). If the protective layer  15  is particularly made of an opaque material, the photo solder resist can be protected from being exposed to light during the process of exposing the photosensitive material layer to light when forming a pattern by etching in subsequent steps. 
     Then, as illustrated in  FIGS. 19 and 20 , the first photosensitive material layer  16  is formed on the metal layer  12 ′ and then is selectively exposed to light and developed, in the steps represented by S 313  and S 315 . The first photosensitive material layer is exposed to light and developed such that it remains on the metal layer  12 ′ in the shape corresponding to that of the first pattern  12 . The second photosensitive material layer  17  can be formed on the other surface of the first resin layer  10 , or on the other surface of the protective layer  15  if the protective layer  15  does exist. The second photosensitive material layer  17  cured by being exposed to light can strengthen any weak intensity because the protective layer  15  functions as a carrier. 
     Next, the metal layer  12 ′ is etched to form the first pattern  12 , and then the first photosensitive material layer  16  is removed in the steps represented by S 317  and S 319 . Since the metal layer  12 ′ in the area where the first photosensitive material remains is protected during the etching, the metal layer  12 ′ exposed to the surface by removing the first photosensitive material layer  16  after etching becomes the first pattern  12  (see reference numerals  21  and  22 ). 
     This process can be also applied to form not only the first pattern  12  but also the second pattern  22  in the same manner. 
     Then, as illustrated in  FIG. 23 , the first conductive bump  34 , which is electrically connected to the first pattern  12 , is formed in the step represented by S 320 . The insulation layer  30  and the first resin layer  10  are compressed such that the conductive bump  34  passes through the insulation layer  30  in the step represented by S 330 , as illustrated in  FIG. 24 . Subsequently, as illustrated in  FIG. 25 , the second resin layer  20 , which has the second pattern  22  formed on the surface thereof facing the insulation layer  30 , is laminated on the insulation layer  30  in the step represented by S 340 . 
     The first resin layer  10  and the second resin layer  20  are then exposed by removing the protective layer  15  in the step represented by S 345 . When the substrate surface treatment process is left to be performed only, the protective layer  15  and the second photosensitive material layer  17  are not needed any more. Accordingly, the protective layer  15  and the second photosensitive material layer  17  are removed. As illustrated in  FIG. 26 , when the second photosensitive material layer  17  is formed on the protective layer  15 , the photosensitive material layer  17  can be removed together with the protective layer  15 . 
     A part of at least one of the first resin layer  10  and the second resin layer  20  is exposed to light and developed such that the opening is formed in the step represented by S 350 . Unlike the embodiment described above, since at least one of the first resin layer  10  and the second resin layer  20  is a photo solder resist, the part of at least one of the first resin layer  10  and the second resin layer  20  is selectively removed by being exposed to light and developed such that the opening can be formed without a drilling process or a laser process. Each of the openings  11  and  21  has a solder ball  40  formed therein so that it is possible to construct a structure capable of providing electrical connection to a mother board or an electronic element such as a semiconductor chip. 
     Illustrated in  FIG. 26  is a printed circuit board manufactured through the process. 
     Since it is not necessary to separately form a solder resist in this embodiment of the present invention, the lead time can be reduced. Moreover, since the first resin layer  10  and the second resin layer  20  are photo solder resists, the drilling process is unnecessary during the forming of an opening, causing less damage to the pattern. In addition, because the protective layer  15  and the second photosensitive material layer  17  can function as a carrier, it is possible to perform a process of forming the printed circuit board without using a separate carrier. 
     That is, an existing solder resist can be substituted by the first resin layer  10  and the second resin layer  20 , thereby simplifying the process without performing an extra process of forming the solder resist and thus remarkably reducing the lead time. 
     While the present invention has been described with reference to certain embodiments thereof, it will be understood by those skilled in the art that various changes and modification in forms and details may be made without departing from the spirit and scope of the present invention as defined by the appended claims. 
     Numerous embodiments other than the embodiments described above are included within the scope of the present invention.