Patent Publication Number: US-2023137656-A1

Title: Wiring circuit board

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims priority from Japanese Patent Application No. 2021-178086 filed on Oct. 29, 2021, the contents of which are hereby incorporated by reference into this application. 
     BACKGROUND ART 
     The present invention relates to a wiring circuit board. 
     Wiring circuit boards each including an insulating base layer, wires with different thicknesses from each other, and an insulating cover layer sequentially toward an upper side are known (for example, see Patent document 1 below). The wires are electrically connected with terminals, respectively. 
     The upper surface of the insulating cover layer, which covers the thickest wire among the wires of the suspension board with circuit of Patent document 1, is located at an upper side as compared to the upper surface of the terminal continuing to the thickest wire. 
     CITATION LIST 
     Patent Document 
     Patent Document 1: Japanese Unexamined Patent Publication No. 2015-158963 
     SUMMARY OF THE INVENTION 
     Problem to be Solved by the Invention 
     An element may electrically be connected with the terminals in an up-down direction by moving the element downward to the upper sides of the terminals. When being projected in the up-down direction, the element overlaps the terminals and the insulating cover layer that is located in proximity to the terminals. The lower surface of the element is flat. Then, the lower surface of the element is brought into contact with the upper surface of the insulating cover layer covering the thickest wire before the lower surface of the element is brought into contact with the upper surface of the first terminal. Thus, there is a disadvantage that the element fails to smoothly be connected to the first terminal. 
     The present invention provides a wiring circuit board that allows the electrical connection of the element with the terminals to be easy and sure. 
     Means For Solving the Problem 
     The present invention [1] includes a wiring circuit board including: an insulating base layer; a plurality of wires with different thicknesses from each other; and an insulating cover layer sequentially toward an upper side, wherein the plurality of wires include a first wire being the thickest wire among the plurality of wires, the wiring circuit board further comprises a plurality of terminals disposed on an upper surface of the insulating base layer, the terminals are electrically connected with the wires, respectively, and an upper surface of each of the terminals is located at an upper side as compared to an upper surface of the insulating cover layer covering the first wire. 
     In the wiring circuit board, the upper surface of each of the terminals is located at an upper side as compared to the upper surface of the insulating cover layer covering the first wire. Thus, when the element is moved downward to the terminals, the contact of the element with the upper surface of the insulating cover layer covering the first wire is suppressed. Thus, the lower surface of the element is easily and surely connected to the upper surfaces of the terminals. 
     The present invention [2] includes the wiring circuit board in [1], wherein the upper surface of each of the terminals is located 1 μm or more above the upper surface of the insulating cover layer. 
     In the wiring circuit board, the contact of the element with the upper surface of the insulating cover layer covering the first wire is more surely suppressed. 
     The present invention [3] includes the wiring circuit board described in [1] or [2], further including a protective metal layer disposed on the upper surface of each of the terminals. 
     In the wiring circuit board, the protective metal layer prevents the corrosion of the terminals. 
     The present invention [4] includes the wiring circuit board described in described in any one of [1] to [3] , wherein at least one of the terminals includes a plurality of conductive layers sequentially toward an upper side. 
     The present invention [5] includes the wiring circuit board described in described in [4], further including: a first conductive layer and a second conductive layer, the first conductive layer and the second conductive layer are sequentially disposed at an upper side of the insulating base layer, wherein at least one of the terminals includes the first conductive layer and the second conductive layer, and each of the wires includes one selected from the group consisting of the first conductive layer and the second conductive layer. 
     The wiring circuit board has a simple structure in which the conductive pattern varies in thickness depending on the functions. 
     The present invention [6] includes the wiring circuit board described in described in [5], wherein at least one of the terminals includes a raising member disposed between the first conductive layer and the second conductive layer. 
     In the wiring circuit board, a terminal includes the raising member. Thus, the upper surface of the terminal is surely located at an upper side as compared to the upper surface of the insulating cover layer covering the first wire. 
     The present invention [7] includes the wiring circuit board described in described in [4], further including: a first conductive layer; a second conductive layer; and a third conductive layer, the first conductive layer, the second conductive layer, and the third conductive layer are sequentially disposed at an upper side of the insulating base layer, wherein at least one of the terminals includes the first conductive layer, the second conductive layer, and the third conductive layer, and each of the wires includes one selected from the group consisting of the first conductive layer, the second conductive layer, and the third conductive layer. 
     The wiring circuit board has a simple structure while the conductive pattern varies in thickness depending on the functions. 
     Effects of the Invention 
     The wiring circuit board of the present invention allows the electrical connection between the element and the terminals to be easy and sure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a plan view partially enlarging one embodiment of the wiring circuit board of the present invention. 
         FIG.  2    is a cross-sectional view of the wiring circuit board of  FIG.  1   , taken along line A-B. 
         FIG.  3 A  to  FIG.  3 D  illustrate the steps of producing the wiring circuit board of  FIG.  2   .  FIG.  3 A  illustrates a step of forming a first conductive layer.  FIG.  3 B  illustrates a step of forming a second conductive layer.  FIG.  3 C  illustrates a step of forming an insulating cover layer.  FIG.  3 D  illustrates a step of forming a protective metal layer. 
         FIG.  4    is a cross-sectional view of the first variation. 
         FIG.  5    is a cross-sectional view of the second variation. 
         FIG.  6    is a cross-sectional view of the third variation. 
         FIG.  7    is a cross-sectional view of the fourth variation. 
     
    
    
     DESCRIPTION OF THE EMBODIMENT 
     1. Wiring Circuit Board  1   
     One embodiment of the wiring circuit board of the present invention is described with reference to  FIG.  1    and  FIG.  2   . A wiring circuit board  1  has a sheet shape with a thickness. The thickness is a length in an up-down direction of  FIG.  2   . The wiring circuit board  1  extends in a surface direction. The surface direction is orthogonal to the up-down direction. The wiring circuit board  1  includes a lower surface  11  and an upper surface  12 . The lower surface  11  is flat. The upper surface  12  is separated upward from the lower surface  11  by an interval therebetween. 
     The wiring circuit board  1  includes an insulating base layer  2 , a conductive pattern  3 , an insulating cover layer  4 , and a protective metal layer  5 . In the present embodiment, the wiring circuit board  1  preferably includes only the insulating base layer  2 , the conductive pattern  3 , the insulating cover layer  4 , and the protective metal layer  5 . 
     1.1 Insulating Base Layer  2   
     The insulating base layer  2  has an outer shape identical to that of the wiring circuit board  1 . The insulating base layer  2  forms the lower surface  11  of the wiring circuit board  1 . The insulating base layer  2  has a sheet shape with a thickness. The insulating base layer  2  has a lower surface and an upper surface, both of which are flat. The upper surface is parallel to the lower surface. Examples of the material of the insulating base layer  2  include insulating resin. Examples of the insulating resin include polyimide. The insulating base layer  2  has a thickness of, for example, 1 μm or more, for example, 1000 μm or less. 
     1.2 Conductive Pattern  3   
     The conductive pattern  3  is disposed on an upper surface of the insulating base layer  2 . Examples of the material of the conductive pattern  3  include copper, silver, gold, iron, aluminum, chromium, and alloys thereof. To achieve good electric properties, copper and a copper alloy are preferable as the material of the conductive layer  3 . The conductive pattern  3  includes a plurality of wires  31  and a plurality of terminals  32 . 
     The wires  31  vary in thickness, that is, the wires  31  have different thicknesses from each other. The wires  31  include a first wire  311  and a second wire  312 . 
     Each of the first wire  311  and the second wire  312  extends in a first direction. The first direction is included in the surface direction. The first wire  311  and the second wire  312  are separated from each other by an interval therebetween in a second direction. The second direction is included in the surface direction and orthogonal to the first direction. The first wire  311  is thicker than the second wire  312 . In other words, in the present embodiment, the first wire  311  is the thickest among the wires  31 . 
     The first wire  311  is, for example, a large current wire for transmitting a relatively large amount of current (a large amount of current of, for example, 1 A or more or 10 A or more). Examples of the first wire  311  include power wires (power source wires). The first wire  311  has a thickness of, for example, 2 μm or more, preferably 5 μm or more, more preferably 10 μm or more, and, for example, 300 μm or less. 
     The second wire  312  is independent (electrically independent) from the first wire  311 . The second wire  312  is, for example, a small current wire for transmitting a small amount of current (for example, of 1 A) as compared to the current (large current) transmitted by the first wire  311 . Examples of the second wire  312  include signal wires (such as differential wires) and ground wires (such as grounding wires). The second wire  312  has a thickness of, for example, 200 μm or less, preferably 100 μm or less, more preferably 50 μm or less, and, for example, 1 μm or more. The ratio of the thickness of the first wire  311  to the thickness of the second wire  312  is, for example, 1.1 or more, preferably 1.25 or more, more preferably 1.5 or more, even more preferably 1.75 or more, particularly preferably 2.0 or more, and, for example, 100 or less, preferably 50 or less. 
     The layer structure of each of the wires  31  is described below. 
     The terminals  32  are provided corresponding to the wires  31 . The terminals  32  are disposed in parallel and separated from each other by an interval therebetween in the second direction. The terminals  32  include a first terminal  321  and a second terminal  322 . 
     The first terminal  321  continues to one edge of the first wire  311  in the first direction. The first terminal  321  is electrically connected to the first wire  311 . In the plan view, the first terminal  321  has a rectangular land shape with a long side in the first direction. Examples of the first terminal  321  include signal terminals and grounding terminals. A signal terminal inputs and outputs a power source current to/from an element  8  (described below). 
     The first terminal  321  is thicker than the first wire  311 . Specifically, an upper surface  321 A of the first terminal  321  is located at an upper side as compared to an upper surface  311 A of the first wire  311 . The number of the first terminals  321  may be one, or two or more. 
     The second terminal  322  continues to one edge of the second wire  312  in the first direction. The second terminal  322  is electrically connected to the second wire  312 . In the plan view, the second terminal  322  has a rectangular land shape with a long side in the first direction. Examples of the second terminal  322  include power source terminals. A power source terminal inputs and outputs a signal, for example, to/from the element  8 . The second terminal  322  is thicker than the second wire  312 . Specifically, an upper surface  322 A of the second terminal  322  is located at an upper side as compared to an upper surface  312 A of the second wire  312 . The number of the second terminals  322  may be one, or two or more. 
     In the present embodiment, for example, the first terminal  321  and the second terminal  322  have the same thickness. Specifically, the upper surface  321 A of the first terminal  321  and the upper surface  322 A of the second terminal  322  are located at the same location in the up-down direction. In the present embodiment, the upper surface  321 A of the first terminal  321  and the upper surface  322 A of the second terminal  322  are located at the uppermost side of the conductive pattern  3 . 
     1.2.1 Layer Structure of Conductive Pattern  3   
     The layer structure of the conductive pattern  3  is described. In the present embodiment, among the terminals  32 , each of the first terminal  321  and the second terminal  322  sequentially includes a plurality of conductive layers  33 . The conductive layers  33  include a first conductive layer  331  and a second conductive layer  332  sequentially toward an upper side. In the present embodiment, each of the first terminal  321  and the second terminal  322  includes a first conductive layer  331  and a second conductive layer  332  sequentially toward an upper side. At one side, the first wire  311  consists of the second conductive layer  332 . At the other side, the second wire  312  consists of the first conductive layer  331 . 
     1.2.2 First Conductive Layer  331   
     The first conductive layers  331  are disposed on the upper surface of the insulating base layer  2 . The first conductive layers  331  are included in the first terminal  321 , the second terminal  322 , and the second wire  312 , respectively. 
     1.2.3 Second Conductive Layer  332   
     In the present embodiment, the second conductive layer  332  is thicker than the first conductive layer  331 . The second conductive layers  332  corresponding to the wires  31  are disposed on the upper surface of the insulating base layer  2 . The second conductive layers  332  corresponding to the terminals  32  are disposed on the upper surface of the first conductive layers  331  corresponding to the terminals  32 . In other words, the second conductive layers  332  are included in the first terminal  321 , the second terminal  322 , and the first wire  311 , respectively. As described above, the first terminal  321  and the second terminal  322  are thicker than the first wire  311  and the second wire  312 , respectively. In other words, each of the upper surface  321 A of the first terminal  321  and the upper surface  322 A of the second terminal  322  is located at an upper side as compared to each of the upper surface  311 A of the first wire  311  and the upper surface  312 A of the second wire  312 . 
     1.3 Insulating Cover Layer  4   
     The insulating cover layer  4  is disposed on the upper surface of the insulating base layer  2 . Further, the insulating cover layer  4  covers the wires  31 . The insulating cover layer  4  is disposed on the upper surface and side surfaces of each of the wires  31 . In this manner, the wiring circuit board  1  includes the insulating base layer  2 , the wires  31 , and the insulating cover layer  4  toward the upper side. Meanwhile, the terminals  32  are exposed from the insulating cover layer  4 . Specifically, when being projected in the up-down direction, the insulating cover layer  4  does not overlap the terminals  32 . Examples of the material of the insulating cover layer  4  include insulating resin. Examples of the insulating resin include polyimide. 
     The insulating cover layer  4  covering the first wire  311  is described. Hereinafter, the insulating cover layer  4  covering the first wire  311  is referred to as a wire covering portion  41 . An upper surface  41 A of the wire covering portion  41  is located at a lower side as compared each of the upper surface  321 A of the first terminal  321  and the upper surface  322 A of the second terminal  322 . In other words, each of the upper surface  321 A of the first terminal  321  and the upper surface  322 A of the second terminal  322  is located at an upper side as compared to the upper surface  41 A of the wire covering portion  41 . 
     Each of the upper surface  321 A of the first terminal  321  and the upper surface  322 A of the second terminal  322  is, for example, 1 μm or more, preferably 2 μm or more, more preferably 5 μm or more above the upper surface  41 A of the wire covering portion  41 , and, for example, 100 μm or less above the upper surface  41 A of the wire covering portion  41 . In other words, the difference D between each of the upper surface  321 A of the first terminal  321  and the upper surface  322 A of the second terminal  322 , and the upper surface  41 A of the wire covering portion  41  is, for example, 1 μm or more, preferably 2 μm or more, more preferably 5 μm or more, and, for example, 100 μm or less in the up-down direction. Thus, when the element  8  is moved downward to the first terminal  321  and the second terminal  322 , the contact of the element  8  with the upper surface  41 A of the wire covering portion  41  can surely be suppressed. 
     In the present embodiment, the wire covering portion  41  is thinner than, for example, each of the first conductive layer  331  and the second conductive layer  332 . Particularly, the wire covering portion  40  is thinner than the first conductive layer  331 . The thickness of the wire covering portion  41  is a length between the upper surface of the wire covering portion  41  and the upper surface  311 A of the first wire  311  in the up-down direction. The thickness of the wire covering portion  41  is, for example, 100 μm or less, preferably 50 μm or less, more preferably 20 μm or less, and, for example, 1 μm or more. 
     1.4 Protective Metal Layer  5   
     The protective metal layer  5  is disposed on the upper surface and side surfaces of each of the terminals  32 . The protective metal layer  5  protects the upper surface and side surfaces of each of the terminals  32 . The protective metal layer  5  has a thin film shape in conformity with the shape of the surface of each of the terminals  32 . The thickness of the protective metal layer  5  is smaller than the thickness of the wire covering portion  41 . Specifically, the thickness of the protective metal layer  5  is, for example, 0.01 μm or more, preferably 0.02 μm or more, more preferably 0.05 μm or more, and, for example, 10 μm or less. The ratio of the thickness of the protective metal layer  5  to the thickness of the insulating cover layer  4  is, for example, 0.1 or less, preferably 0.01 or less, and, for example, 0.00001 or more. Examples of the material of the protective metal layer  5  include corrosion-resistant materials. Examples of the corrosion-resistant material include nickel and gold. In the present embodiment, the material of the protective metal layer  5  is preferably different from that of the conductive pattern  3 . The protective metal layer  5  is single-layered or multiple-layered. 
     1.5 Method of Producing Wiring Circuit Board  1   
     A method of producing the wiring circuit board  1  is described with reference to  FIGS.  3 A to  3 D . As illustrated in  FIGS.  3 A to  3 D , the method of producing the wiring circuit board  1  includes, for example, a first step, a second step, a third step, a fourth step, and a fifth step. 
     1.5.1 The First Step 
     As illustrated in  FIG.  3 A , the insulating base layer  2  is prepared in the first step. For example, the above-described resin is applied on the surface of a supporting sheet not illustrated, and, as necessary, photolithography is carried out to form the insulating base layer  2  into an appropriate pattern. Alternatively, an insulating base layer  2  that is formed into a sheet shape in advance is prepared without any change. 
     1.5.2 The Second Step 
     As illustrated in  FIG.  3 A  and  FIG.  3 B , the conductive pattern  3  is formed on the upper surface of the insulating base layer  2  in the second step. The second step includes a step of forming the first conductive layer  331  and a step of forming the second conductive layer  332 . 
     1.5.2.1 Step of Forming First Conductive Layer  331   
     As illustrated in  FIG.  3 A , in the step of forming the first conductive layer  331 , the first conductive layer  331  is formed on the upper surface of the insulating base layer  2  by an additive method or a subtractive method. In this manner, the second wire  312  consisting of the first conductive layer  331  is formed. 
     1.5.2.2 Step of Forming Second Conductive Layer  332   
     Next, as illustrated in  FIG.  3 B , the second conductive layer  332  is formed on the upper surfaces of parts of the first conductive layer  331  corresponding to the first terminal  321  and the second terminal  322  and on the upper surface of the insulating base layer  2  by an additive method or a subtractive method. In this manner, the first wire  311  consisting of the second conductive layer  332  is formed. At the same time, each of the first terminal  321  and the second terminal  322 , in both of which the first conductive layer  331  and the second conductive layer  332  are sequentially disposed, are formed. 
     1.5.3 The Third Step 
     As illustrated in  FIG.  3 C , in the third step, the insulating cover layer  4  is disposed on a one-side surface in the thickness direction of the insulating base layer  2  to cover the wires  31 . For example, a photosensitive resin is applied to the insulating base layer  2  and the conductive pattern  3 , and photolithography is carried out to form a pattern from which the terminals  32  are exposed. 
     1.5.4 The Fourth Step 
     As illustrated in  FIG.  3 D , in the fourth step, the protective metal layer  5  is formed on the surface of the terminal  32 , for example, by plating. 
     1.6 Connection between Wiring Circuit Board  1  and Element  8   
     As the phantom lines of  FIG.  2    show, the element  8  is disposed at an upper side of the terminals  32  in the wiring circuit board  1 , being separated from the terminals  32  by an interval therebetween. The element  8  has an approximate box shape in the cross-sectional view. A lower surface  80  of the element  8  is flat. The lower surface  80  of the element  8  includes a first electrode  81  and a second electrode  82 . The first electrode  81  is, for example, a power source electrode. The second electrode  82  is, for example, a signal electrode or a grounding electrode. 
     Next, the element  8  is moved closer to the upper surface  12  of the wiring circuit board  1 . Specifically, the first electrode  81  is moved closer to the upper surface  321 A of the first terminal  321 . The second electrode  82  is moved closer to the upper surface  322 A of the second terminal  322 . 
     In this manner, the first terminal  321  is electrically connected to the first electrode  81 . The second terminal  322  is electrically connected to the second electrode  82 . 
     2. Operations and Effects of One Embodiment 
     In the wiring circuit board  1 , each of the upper surface  321 A of the first terminal  321  and the upper surface  322 A of the second terminal  322  is located at an upper side as compared to the upper surface  41 A of the wire covering portion  41 . Thus, when the element  8  is moved downward to the first terminal  321  and the second terminal  322 , the contact of the lower surface  80  of the element  8  with the upper surface  41 A of the wire covering portion  41  is suppressed. Therefore, the first electrode  81  and the second electrode  82  are easily and surely connected to the upper surface  321 A of the first terminal  321  and the upper surface  322 A of the second terminal  322 , respectively. 
     In the wiring circuit board  1 , each of the upper surface  321 A of the first terminal  321  and the upper surface  322 A of the second terminal  322  is, for example, 1 μm or more above the upper surface  41 A of the wire covering portion  41 . Thus, the contact of the lower surface  80  of the element  8  with the upper surface  41 A of the wire covering portion  41  is more surely suppressed. 
     The wiring circuit board  1  further includes the protective metal layer  5 . Thus, the corrosion of the terminals  32  is prevented. 
     In the wiring circuit board  1 , each of the first terminal  321  and the second terminal  322  includes the first conductive layer  331  and the second conductive layer  332 . Meanwhile, the first wire  311  consists of the second conductive layer  332  whereas the second wire  312  consists of the first conductive layer  331 . As described above, in the conductive pattern  3 , the wires  31 , which have different thicknesses from each other, and the terminals  32 , which are thicker than the wires  31  and have the same thickness, are formed from the above-described first conductive layer  331  and second conductive layer  332 . Thus, the wiring circuit board  1  has a simple structure while the conductive pattern  3  varies in thickness depending of the functions. 
     3. Variations 
     In each of the variations, the same members and steps as in one embodiment will be given the same reference numerals and the detailed descriptions thereof will be omitted. Further, each of the variations can have the same operations and effects as those of one embodiment unless especially described otherwise. Furthermore, one embodiment and the variations can appropriately be combined. 
     3.1 The First Variation 
     As illustrated as  FIG.  4   , the conductive pattern  3  further includes a third conductive layer  333 . 
     As shown at the left side of  FIG.  4   , for example, the third conductive layer  333  is disposed on the upper surface of the second conductive layer  332  of each of the first terminal  321  and the second terminal  322 . 
     In the first variation, each of the first terminal  321  and the second terminal  322  includes the first conductive layer  331 , the second conductive layer  332 , and the third conductive layer  333  sequentially toward an upper side. Thus, each of the upper surface  321 A of the first terminal  321  and the upper surface  322 A of the second terminal  322  is surely located at an upper side as compared to the upper surface  41 A of the wire covering portion  41 . 
     The first variation has a simple structure while the conductive pattern  3  including the first conductive layer  331 , the second conductive layer  332 , and the third conductive layer  33  varies in thickness depending on their functions. 
     3.2 The Second Variation 
     As illustrated in  FIG.  5   , the third conductive layer  333  is included also in the first wire  311 . On the other hand, the second conductive layer  332  is not included in the first wire  311 . 
     3.3 The Third Variation 
     As illustrated in  FIG.  6   , each of the first terminal  321  and the second terminal  322  includes a raising member  6 . The raising member  6  raises each of the upper surface  321 A of the first terminal  321  and the upper surface  322 A of the second terminal  322  to an upper side. The raising member  6  has a board shape. The raising member  6  is included in the outer shape of each of the first terminal  321  and the second terminal  322  when being projected in the up-down direction. In each of the first terminal  321  and the second terminal  322 , the peripheral edge portion of the first conductive layer  331  is in contact with the peripheral edge portion of the second conductive layer  332  around the raising member  6 . In the present embodiment, the material of the raising member  6  is an insulating material. In the present embodiment, the material of the raising member  6  is the same as that of the insulating cover layer  4  (preferably, polyimide). The raising member  6  has a thickness of, for example, 1 μm or more, preferably 2 μm or more, more preferably 5 μm or more, and, for example, 100 μm or less. Preferably, the thickness of the raising member  6  is identical to the thickness of the insulating cover layer  4 . 
     In the third variation, each of the first terminal  321  and the second terminal  322  includes the raising member  6 . Thus, each of the upper surface  321 A of the first terminal  321  and the upper surface  322 A of the second terminal  322  is surely located at an upper side as compared to the upper surface  41 A of the wire covering portion  41 . 
     3.4 The Fourth Variation 
     As illustrated in  FIG.  7   , the second terminal  322  may intervene in an intermediate part of the second wire  312  in the first direction. 
     3.5 The Fifth Variation 
     As the phantom lines of  FIG.  2    show, the wiring circuit board  1  further include a metal supporting board  7 . The metal supporting board  7  is disposed on the lower surface of the insulating base layer  2 . Examples of the material of the metal supporting board  7  include iron, stainless steels, copper, and copper alloys. 
     While the illustrative embodiments of the present invention are provided in the above description, such is for illustrative purpose only and it is not to be construed as limiting in any manner Modification and variation of the present invention that will be obvious to those skilled in the art is to be covered by the following claims. 
     DESCRIPTION OF REFERENCE NUMERALS 
       1  wiring circuit board 
       2  insulating base layer 
       3  conductive pattern 
       31  wires 
       32  terminals 
       33  conductive layers 
       311  first wire 
       311 A upper surface of the first wire 
       321 A upper surface of the first terminal 
       322 A upper surface of the second terminal 
       331  first conductive layer 
       332  second conductive layer 
       333  third conductive layer 
       4  insulating cover layer 
       41 A upper surface of the wire covering portion 
       5  protective metal layer 
       6  raising member