JP5302831B2 - Wiring board manufacturing method - Google Patents

Description

  The present invention provides a wiring board comprising: a wiring provided on a surface of a substrate having a through hole provided with no electrode; and a through wiring provided on an inner surface of the through hole and electrically connected to the wiring. It relates to a manufacturing method.

Conventionally, the following method has been disclosed as a method for manufacturing a double-sided wiring board in which wirings are formed on both surfaces of a substrate and these wirings are electrically connected to each other through through holes.
A first wiring pattern is formed on the surface of the substrate provided with the through hole by a conductive paste such as a silver paste having flowability by a screen printing method or the like. At this time, printing is also performed on the through hole.
As described above, when the conductive paste is printed on the surface of the substrate, the conductive paste immediately flows down the inner surface of the through hole and stops at the center of the through hole.

After heating the board | substrate with which the 1st wiring pattern was formed and drying an electrically conductive paste, a board | substrate is turned upside down and a back surface side is arrange | positioned upward.
Next, a second wiring pattern is formed on the back surface of the substrate with a conductive paste having flowability by screen printing or the like. At this time, printing is also performed on the through hole.
Thus, when the conductive paste is printed on the back surface of the substrate, the conductive paste immediately flows down the inner surface of the through hole, and the tip of the conductive paste from the back surface of the substrate is conductive from the front surface side of the substrate. The conductive paste contacts the tip of the paste and slightly overlaps the conductive paste.
By performing a drying process in this state, the conductive paste on the front side of the substrate and the conductive paste on the back side of the substrate are fixed in a state of being electrically connected through a through hole (for example, Patent Document 1-3).

Japanese Patent Laid-Open No. 8-236891 Japanese Patent Laid-Open No. 2003-6589 JP 2004-310718 A

In the conventional method for manufacturing a double-sided wiring board, if the force for applying the conductive paste to the substrate at the time of printing is weak, the conductive paste is not sufficiently filled in the through hole. Then, the conductive paste printed on the through hole flows down into the through hole. Then, since the conductive paste such as silver paste has a heavy specific gravity of conductive particles such as silver particles contained therein, the conductive paste falls without staying inside the through hole. Therefore, the conductive paste printed on the front or back surface of the substrate and the conductive paste that has flowed down into the through hole are at the boundary between the front or back surface of the substrate and the through hole (opening end of the through hole). As a result, the conductive paste does not remain inside the through hole, and as a result, there is a problem that no wiring is formed inside the through hole. Even if the conductive paste remains on the inner surface of the through hole, the amount of the conductive paste is small, and the conductive paste shrinks due to drying. There is a problem that the formed wiring and the wiring formed on the inner surface of the through hole are disconnected at the opening end of the through hole.
In addition, the conductive paste may cover the opening of the through hole without falling down from the through hole. In this case, since air accumulates in the through hole, there is a problem that the conductive paste does not remain on the inner surface of the through hole.

  Therefore, the present inventors have formed the wiring pattern made of the conductive paste by printing, and provided the uncoated portion of the conductive paste including at least the central portion of the through hole in the wiring pattern, thereby solving the above-mentioned problem. I found that it can be solved. That is, the present inventors formed a wiring pattern made of a conductive paste by printing so that an uncoated portion of the conductive paste is opposed to the opening of the through hole. It was found that the conductive paste can be sufficiently applied.

  However, in the manufacture of such a double-sided wiring board, after forming a through hole in the substrate, the conductive paste is printed on both sides of the base material, and the conductive paste is also printed on the through hole. The conductive paste is filled therein, and in that case, the position of the uncoated portion may be shifted in printing the conductive paste on the through hole. Therefore, there is a problem that the conductive paste cannot be sufficiently applied to the inner side surface of the through hole.

  The present invention has been made in view of the above circumstances, in which wiring is formed with a conductive paste on one surface or the other surface of a substrate, and the inner surface of a through-hole formed in the substrate is electrically conductive. It is an object of the present invention to provide a method of manufacturing a wiring board that can reliably form a through wiring electrically connected to a wiring formed on one surface or the other surface of the substrate by using a paste.

  The method for manufacturing a wiring board according to the present invention includes a board, a wiring provided on the board, a land portion connected to the wiring, and an inner surface of a through hole of the board, and is electrically connected to the wiring. And a through wiring for electrically connecting to the other surface, wherein the conductive paste is printed on one surface of the substrate provided with at least one through hole by printing. And a land portion pattern made of the conductive paste that includes the open end of the through-hole and is connected to the wiring pattern, and the land portion pattern has an unexposed portion of the conductive paste. Forming a conductive pattern made of the conductive paste on the inner surface of the through-hole by providing a slit forming region in which a plurality of coated portions are provided at regular intervals in a slit shape; Pattern B, the land portion pattern and the conductive pattern are cured to form a wiring, a land portion and a through wiring, and in the step A, the through hole is arranged at the center of the slit forming region. In this case, the diameter of the through hole is D, the pitch between two uncoated portions adjacent to each other among the plurality of uncoated portions is P, the width of the uncoated portion is W, the length of the uncoated portion is L, In the land pattern, the slit forming region satisfying the relationship of D> W, D> P−W, and L ≧ D + 2α, where 2α is a positional deviation allowable in the length direction of the uncoated portion. The land part pattern having the following is formed.

  According to the method for manufacturing a wiring board of the present invention, the printed circuit board includes the conductive paste that includes the opening end of the through hole and is connected to the wiring pattern by printing on one surface of the board provided with at least one through hole. The land portion pattern is formed, and the land portion pattern is formed of a conductive paste on the inner surface of the through hole by providing a slit forming region in which a plurality of uncoated portions of the conductive paste are provided in a slit shape at equal intervals. In the step A of forming the conductive pattern, when a through hole is arranged at the center of the slit forming region, the diameter of the through hole is D, the pitch of two uncoated portions adjacent to each other among the plurality of uncoated portions is P, uncoated If the width of the portion is W, the length of the uncoated portion is L, and the width of the positional deviation allowed in the length direction of the uncoated portion in the land pattern is 2α, D> W, D> P−W Since the land portion pattern having the slit forming region satisfying the relationship of L ≧ D + 2α is formed, even if the position of the land portion pattern forming region of the printing plate is displaced, the uncoated portion of the conductive paste (air Since at least a part of the hole overlaps the opening of the through hole, the unapplied part (air hole) makes it difficult for air to accumulate in the through hole, and the conductive paste flows smoothly into the through hole. An appropriate amount of conductive paste can be applied to the inner surface of the through hole. Therefore, since no disconnection occurs in the through wiring formed by curing the conductive pattern made of the conductive paste applied to the inner side surface of the through hole, the conductivity of the through wiring can be further improved.

It is a schematic plan view which shows one Embodiment of the wiring board produced by the manufacturing method of the wiring board of this invention, (a) is a top view, (b) is a bottom view. It is a schematic plan view which shows one Embodiment of the manufacturing method of the wiring board of this invention. It is a schematic plan view which shows one Embodiment of the manufacturing method of the wiring board of this invention. FIG. 4 is a schematic plan view showing a first embodiment of a process A in an embodiment of a method for manufacturing a wiring board of the present invention, and is an enlarged view of a portion indicated by reference sign α in FIG. 3. FIG. 4 is a schematic plan view showing a second embodiment of the process A in an embodiment of the method for manufacturing a wiring board of the present invention, and is an enlarged view of a portion indicated by reference sign α in FIG. 3.

An embodiment of a method for manufacturing a wiring board according to the present invention will be described.
This embodiment is specifically described for better understanding of the gist of the invention, and does not limit the present invention unless otherwise specified.

FIG. 1 is a schematic plan view showing an embodiment of a wiring board manufactured by the method for manufacturing a wiring board according to the present invention, wherein (a) is a top view and (b) is a bottom view.
The wiring substrate 10 of this embodiment includes a substrate 11, a wiring 12 provided on one surface 11a of the substrate 11, a wiring 13 provided on the other surface 11b of the substrate 11, and one surface 11a of the substrate 11. The land portions 14 and 15 connected to the wiring 12, the land portions 16 and 17 connected to the other surface 11 b of the substrate 11, and the inner surfaces of the through holes 18 and 19 of the substrate 11. And a through wiring 20 that electrically connects the land portion 14 and the land portion 16, and a through wiring 21 that electrically connects the land portion 15 and the land portion 17.

  The wiring 12 is formed in a coil shape on one surface 11a of the substrate 11 with the land portion 14 as a starting end and the land portion 15 as an end. The land portion 14 and the land portion 15 are provided with a predetermined interval.

The through holes 18 and 19 are circular pores in a plan view provided so as to penetrate the substrate 11 in the thickness direction. That is, the through holes 18 and 19 are provided perpendicular to the one surface 11 a and the other surface 11 b of the substrate 11.
Further, the through hole 18 and the through hole 19 are provided at a predetermined interval.

  The land portions 14 and 15 are regions to which conductive paste is applied in order to form the through wirings 20 and 21 in the through holes 18 and 19. The land portions 14 and 15 are electrically conductive with respect to the through holes 18 and 19 in this region. This is a region that allows positional deviation in the application of the adhesive paste. That is, the land portion 14 is provided so as to include at least the opening end portion 18 a of the through hole 18. Similarly, the land portion 15 is provided so as to include at least the opening end portion 19 a of the through hole 19.

  The wiring 13 is formed on the other surface 11 b of the substrate 11 in a straight line shape having a land portion 16 as a starting end and a land portion 17 as a terminating end. The land portion 16 and the land portion 17 are provided at a predetermined interval.

  The land portions 16 and 17 are regions to which conductive paste is applied in order to form the through wirings 20 and 21 in the through holes 18 and 19. The land portions 16 and 17 are electrically conductive with respect to the through holes 18 and 19 in this region. This is a region that allows positional deviation in the application of the adhesive paste. That is, the land portion 16 is provided so as to include at least the opening end portion 18 a of the through hole 18. Similarly, the land portion 17 is provided so as to include at least the opening end portion 19 a of the through hole 19.

  The wiring 12 provided on one surface 11 a of the substrate 11 and the wiring 13 provided on the other surface 11 b of the substrate 11 are electrically connected via the through wirings 20 and 21, The wiring 13 forms one circuit.

  As the substrate 11, at least in the surface layer portion, a woven fabric made of inorganic fibers such as glass fibers or alumina fibers, a nonwoven fabric, a mat, paper, or a combination thereof, or a woven fabric made of organic fibers such as polyester fibers or polyamide fibers. Cloth, non-woven fabric, mat, paper, etc., or a combination thereof, or a covering member formed by impregnating them with a resin varnish, polyamide resin substrate, polyester resin substrate, polyolefin resin substrate, polyimide resin substrate , Ethylene-vinyl alcohol copolymer substrate, polyvinyl alcohol resin substrate, polyvinyl chloride resin substrate, polyvinylidene chloride resin substrate, polystyrene resin substrate, polycarbonate resin substrate, acrylonitrile butadiene styrene copolymer resin substrate, poly Ether sulfone Resin substrates, plastic substrates such as (glass) epoxy resin substrates, or mat processing, corona discharge processing, plasma processing, ultraviolet irradiation processing, electron beam irradiation processing, flame plasma processing, ozone processing, or various types of easy adhesion processing. Selected from known materials such as those subjected to surface treatment.

The wirings 12, 13 and the land portions 14, 15, 16, 17 are formed by screen printing in a predetermined pattern using a conductive paste.
The through wirings 20 and 21 are formed of conductive paste simultaneously with the formation of the land portions 14 and 15 and the land portions 16 and 17.

  As the conductive paste, a silver paste in which silver fine particles are blended in a resin composition, a carbon paste in which carbon fine particles are blended in a resin composition, or the like is used.

  If a thermosetting resin is used as the resin composition, the conductive paste becomes a thermosetting type capable of forming a coating film forming the wirings 12 and 13 at 200 ° C. or less, for example, about 100 to 150 ° C. In addition to the thermosetting type, the conductive paste in the present invention may be a known type such as an ultraviolet curable type, a permeation drying type, or a solvent volatile type.

The ultraviolet curable conductive paste contains a photocurable resin in the resin composition and has a short curing time, so that the production efficiency can be improved.
Examples of the ultraviolet curable conductive paste include, for example, a thermoplastic resin alone or a blend resin composition of a thermoplastic resin and a crosslinkable resin (particularly, a crosslinkable resin composed of polyester and isocyanate) and 60 masses of conductive fine particles. % Or more and 10% by mass or more of a polyester resin, that is, a solvent volatile type or a crosslinked / thermoplastic combined type (however, the thermoplastic type is 50% by mass or more), or a thermoplastic resin Or a blend resin composition of a thermoplastic resin and a crosslinkable resin (especially a crosslinkable resin composed of polyester and isocyanate, etc.) containing 10% by mass or more of a polyester resin, that is, a crosslinkable type or a crosslinkable / A thermoplastic combination type is preferably used.

Next, with reference to FIGS. 1-5, the manufacturing method of this wiring board 10 is illustrated, and the manufacturing method of the wiring board of this invention is demonstrated.
First, through holes 18 and 19 that penetrate the substrate 11 in the thickness direction are formed in the substrate 11 at predetermined positions on the substrate 11 by a drill or a laser. At this time, the through hole 18 and the through hole 19 are formed at a predetermined interval.

Next, as shown in FIG. 2, the wiring pattern 12 </ b> A made of a conductive paste and the open end portions 18 a of the through holes 18, 19 are printed on one surface 11 a of the substrate 11 provided with the through holes 18, 19. , 19a and land patterns (hereinafter referred to as “land pattern”) 14A, 15A made of a conductive paste connected to the wiring pattern 12A, and the land patterns 14A, 15 A slit forming region is provided in which a plurality of uncoated portions (not shown) of the conductive paste are provided at regular intervals in a slit shape.
Thereby, a part of the conductive paste applied to form the land pattern 14A, 15A on the one surface 11a of the substrate 11 (the conductive paste applied to form the land pattern 14A, 15A). Of the through holes 18 and 19) flow down into the through holes 18 and 19, and the conductive patterns 20 </ b> A made of the conductive paste are formed on the inner surfaces of the through holes 18 and 19. A part of 21A is formed (step A).

  Here, the uncoated portion of the conductive paste is a portion of the land pattern 14A, 15A where the conductive paste is not coated.

In this step A, the thickness of the wiring pattern 12A and the land pattern 14A, 15A formed on the one surface 11a of the substrate 11 is preferably 2.5 μm to 75 μm, more preferably 17 μm to 27 μm. is there.
In the process A, the thickness of the conductive patterns 20A and 21A formed on the inner side surfaces of the through holes 18 and 19 is preferably 2.5 μm to 75 μm, more preferably 17 μm to 27 μm.

The printing method used in step A is not particularly limited as long as it is a method capable of printing a viscous conductive paste, and depending on the thickness of the substrate, for example, screen printing, gravure printing, flexographic printing, offset printing, etc. The printing method using the printing plate is applied.
For example, when screen printing is applied, a screen plate 30 as shown in FIGS. 3, 4 and 5 is used as the printing plate. Specifically, the screen plate 30 forms a screen base 31, a mesh region 32 that forms the wiring pattern 12 </ b> A, and land patterns 14 </ b> A and 15 </ b> A provided along one surface 31 a of the screen base 31. It consists of mesh regions 33 and 34. The mesh region 32 and the mesh regions 33 and 34 are portions where the conductive paste is applied.

  Further, in the mesh regions 33 and 34, when the screen plate 30 is disposed at a predetermined position on the one surface 11a of the substrate 11, the portions overlapping with the through holes 18 and 19 are blocked with an emulsion or the like. An uncoated portion of the paste (hereinafter referred to as “uncoated portion”) is provided. The mesh regions 33 and 34 are provided with slit forming regions in which a plurality of slit-shaped uncoated portions are provided at equal intervals.

“First embodiment of step A”
With reference to FIG. 4, 1st embodiment of the process A is described.
In this embodiment, a case where through holes 18 and 19 corresponding to land portions 14 and 15 formed on one surface 11a of substrate 11 are provided one by one will be described.
Here, in order to simplify the description, the relationship between the uncoated portion and the through hole 18 in the mesh region 33 will be described.

The mesh area 33 of the screen plate 30 is provided with a slit forming area in which five slit-shaped uncoated portions 33a are provided at equal intervals.
Here, in the mesh region 33, the region surrounded by the slit-like uncoated portion 33a provided on the outermost side (in FIG. 4, a rectangular region having a length of L and a width of M) is defined as a slit formation region. To do.
Further, the shape of the uncoated portion 33a is rectangular in plan view, the width W of all the uncoated portions 33a is equal, and the length L of all the uncoated portions 33a is equal. Yes. That is, five uncoated portions 33a having a rectangular shape in plan view are provided at equal intervals. The portion other than the uncoated portion 33a in the mesh region 33 is a portion that transmits the conductive paste and forms a schematic shape of the land pattern 14A.

  In this embodiment, the mesh region 33 is provided with slit forming regions in which five slit-shaped uncoated portions 33a are provided at equal intervals. The uncoated portion 33a provided from one edge of the mesh region 33 to the other edge of the mesh region 33 is disposed at equal intervals along the x direction (vertical direction of the paper surface) of the mesh region 33. Say that it is.

  Moreover, as the screen plate 30, when the through-hole 18 is arrange | positioned in the center of a slit formation area, the diameter of the through-hole 18 is set to D in the mesh area | region 33, and two adjacent uncoated parts among the five uncoated parts 33a. In P, the pitch of 33a (distance between the center lines along the length direction of the uncoated portion 33a) is P, the width of the uncoated portion 33a is W, the length of the uncoated portion 33a is L, and the land portion pattern 14A is a conductive paste. If the width of the positional deviation allowed in the length direction of the uncoated portion, that is, the width of the positional deviation allowed in the length direction of the uncoated portion 33a in the mesh region 33 is 2α, D> W, D A material having a slit formation region satisfying the relationship of> P−W and L ≧ D + 2α is used.

  In other words, when the distance between two uncoated portions 33a adjacent to each other among the five uncoated portions 33a is Q, the relationship between the distance Q and the pitch P and the width W is expressed by the following relational expression: Q = P−W, and the distance Q between the two unapplied portions 33a adjacent to each other is smaller than the diameter D of the through hole 18 (D> P−W = Q). In this way, even when a displacement of the mesh region 33 of the screen plate 30 occurs in the printing of the conductive paste on the one surface 11a of the substrate 11, at least a part of the uncoated portion 33a of the through hole 18 is formed. It overlaps with the opening (region inside the opening end 18a of the through hole 18).

In the process A, the land portion pattern 14A is formed so that the through hole 18 is arranged at the center of the slit forming region formed in the land portion pattern 14A (mesh region 33). At the time of applying (printing) the paste, misalignment may occur when the mesh region 33 is arranged with respect to the through hole 18, so the mesh region 33 needs to have a size that allows the misalignment.
Therefore, with the center of the mesh region 33 as a reference, the width of the positional deviation in one direction of the expected mesh region 33 in the y direction (the vertical direction of the paper surface, the length direction of the uncoated portion 33a) is α, and the through hole 18 is When the diameter is D, the length L of the uncoated portion 33a needs to satisfy the relational expression L ≧ D + 2α.
Further, when the width of the positional displacement in one direction of the expected mesh region 33 in the x direction (the horizontal direction of the paper surface) is β and the through hole 18 is the diameter D with respect to the center of the mesh region 33, the mesh region 33 In the x direction, the length M from the left end to the right end when the five uncoated portions 33a are made into one lump needs to satisfy the relational expression M ≧ D + 2β.

Further, the length X in the x direction of the mesh region 33 is larger than the length M (X> M) in order to prevent the land portion pattern 14A from being disconnected at the edge by the uncoated portion 33a. It has become. Similarly, the length Y in the y direction of the mesh region 33 is larger than the length L of the uncoated portion 33a (Y> L).
When the slit forming area is defined as described above, the mesh area 33 may be an area larger than the slit forming area, and the shape thereof is not particularly limited, and may be a circle or an ellipse.

  When the land pattern 14A made of a conductive paste is formed on one surface 11a of the substrate 11 provided with the through holes 18 by printing using such a screen plate 30, the land pattern 14A has a conductive A slit forming region is provided in which five uncoated portions of the conductive paste are provided at regular intervals in a slit shape. That is, since the conductive paste cannot pass through the unapplied portion 33a of the mesh region 33, the conductive paste is not applied to the portion, and the portion becomes an uncoated portion.

  Therefore, when the through hole 18 is arranged in the center of the slit forming region in the land pattern 14A formed by the mesh region 33 by using the screen plate 30, the diameter of the through hole 18 is set to D, five uncoated Positions allowed in the length direction of the uncoated portion in the pitch of two uncoated portions adjacent to each other in the portion P, the width of the uncoated portion W, the length of the uncoated portion L, and the land pattern 14A When the width of the shift is 2α, a land portion pattern 14A having a slit formation region that satisfies the relationship of D> W, D> P−W, and L ≧ D + 2α is formed.

  As described above, if the land pattern 14A made of the conductive paste is formed by printing using the screen plate 30, the mesh region 33 of the screen plate 30 is printed in the printing of the conductive paste on the one surface 11a of the substrate 11. Even if the positional deviation occurs, the conductive paste for forming the conductive pattern 20 </ b> A can be sufficiently applied to the inner surface of the through-hole 18.

  In other words, even if the through hole 18A is located at the position 18B or 18C as shown in FIG. 4, for example, these positions are within the area of the land portion pattern 14A, that is, one of the substrates 11 When the screen plate 30 is arranged on the surface 11a, if it is in a region overlapping with the mesh region 33, at least a part of the uncoated portion 33a is an opening portion of the through hole 18 (inside the opening end portion 18a of the through hole 18). Therefore, the conductive paste for forming the conductive pattern 20 </ b> A can be sufficiently applied to the inner surface of the through-hole 18.

"Second embodiment of step A"
With reference to FIG. 5, 2nd embodiment of the process A is described.
Here, in order to simplify the description, the relationship between the uncoated portion and the through hole 18 in the mesh region 33 will be described.
This embodiment is different from the first embodiment in that three through holes 18 corresponding to the land portions 14 formed on the one surface 11a of the substrate 11 are provided. The three through holes 18 (18D, 18E, 18F) are arranged at equal intervals.

  As described above, if the through holes 18D, 18E, and 18F are arranged at equal intervals in the substrate 11 and the screen plate 30 similar to that of the first embodiment is used in the process A, the conductivity to the one surface 11a of the substrate 11 will be described. Even when the mesh region 33 of the screen plate 30 is misaligned in the printing of the conductive paste, at least a part of the uncoated portion 33a is any one of the through holes 18D, 18E, and 18F or all the opening portions ( It overlaps with the area inside the opening end 18a of the through hole 18).

Therefore, if the land pattern 14A made of the conductive paste is formed by printing using the screen plate 30, the position of the mesh region 33 of the screen plate 30 in the printing of the conductive paste on the one surface 11a of the substrate 11 will be described. Even if the displacement occurs, the conductive paste for forming the conductive pattern 20A can be sufficiently applied to any one of the through holes 18D, 18E, and 18F or the entire inner surface.
As shown in FIG. 5, if the interval between the through holes 18D, 18E, and 18F is different from the interval between the uncoated portions 33a, the mesh region 33 of the screen plate 30 is displaced when the displacement occurs. The uncoated portion 33a can be disposed at the center of any of the holes 18D, 18E, and 18F. For example, in FIG. 5, in the normal position, the uncoated portion 33a is arranged at the center of the through hole 18D. However, when the mesh region 33 of the screen plate 30 is displaced, the through hole 18I An uncoated portion 33a is disposed in the center.

  In other words, even if the through holes 18D, 18E, and 18F are located at the positions of the through holes 18G, 18H, and 18I as shown in FIG. 5, for example, these positions are within the area of the land pattern 14A, that is, When the screen plate 30 is disposed on the one surface 11a of the substrate 11, if it is within the region overlapping the mesh region 33, at least a part of the uncoated portion 33a is one of the through holes 18D, 18E, and 18F. Alternatively, since it overlaps with all the openings, the conductive paste for forming the conductive pattern 20A can be sufficiently applied to any one of the through holes 18D, 18E, and 18F or to the entire inner surface.

  In the first embodiment and the second embodiment described above, the mesh region 34 corresponding to the land pattern 15A has the same configuration as the mesh region 33. Thus, the land pattern 15A and the conductive pattern are formed. The pattern 21A is formed in the same manner as the land portion pattern 14A and the conductive pattern 20A.

  Further, in the process A, the screen pattern printing of the conductive paste using the screen plate 30 as described above enables the formation of the wiring pattern 12A on the one surface 11a of the substrate 11 and the land portion pattern 14A, by one operation. The formation of 15A, the formation of a part of the conductive pattern 20A on the inner side surface of the through hole 18 and the formation of a part of the conductive pattern 21A on the inner side surface of the through hole 19 can be performed almost simultaneously. More specifically, for example, a screen plate 30 is disposed on one surface 11a of the substrate 11 provided with the through holes 18, and an appropriate amount of conductive paste is placed on the screen plate 30 with a spatula (squeegee). By extending, the wiring pattern 12A and land portion patterns 14A and 15A made of conductive paste are formed on one surface 11a of the substrate 11, and the conductive paste flows down into the through holes 18 so that the through holes 18 A part of the conductive pattern 20A made of the conductive paste is formed on the inner side surface, and the conductive paste flows down into the through hole 19, and the inner side surface of the through hole 19 is made of the conductive paste. A part of the conductive pattern 21A is formed.

  Next, the wiring pattern 12A, the land portion patterns 14A and 15A, and the conductive patterns 20A and 21A are cured to form the wiring 12 and the land portions 14 and 15 on one surface 11a of the substrate 11, and the through holes 18 are formed. A part of the through wiring 20 is formed on the inner side surface, and a part of the through wiring 21 is formed on the inner side surface of the through hole 19 (step B).

In this step B, when a thermosetting conductive paste is used, the substrate 11 on which the wiring pattern 12A, the land pattern 14A, 15A, and part of the conductive pattern 20A, 21A are formed is heated to 100 to 150 ° C. At 20 to 60 minutes.
Further, in the process B, when the ultraviolet curable conductive paste is used, the wiring pattern 12A, the land pattern 14A, 15A, and the conductive patterns 20A, 21A formed on the substrate 11 are irradiated with ultraviolet rays. To do.

  Next, the substrate 11 on which the wiring 12, the land portions 14 and 15, the through wiring 20, and a part of the through wiring 21 are formed is inverted (turned over) so that the wiring 12 faces downward, and the other surface 11 b of the substrate 11 is For example, it is placed on a flat surface such as a work table.

  Thereafter, the wiring 13 and the land portions 16 and 17 are formed on the other surface 11b of the substrate 11 and a part of the through wiring 20 is formed on the inner surface of the through hole 18 in the same manner as in the above-described Step A and Step B. In addition, a part of the through wiring 21 is formed on the inner surface of the through hole 19. Thereby, a part of the through wiring 20 and the through wiring 21 formed from the one surface 11a side of the substrate 11 and a part of the through wiring 20 and the through wiring 21 formed from the other surface 11b side of the substrate 11 are connected. Then, the formation of the through wiring 20 and the through wiring 21 is completed, and the wiring substrate 10 is obtained.

  According to the method for manufacturing a wiring board of this embodiment, in step A, the mesh region 33 is provided with slit formation regions in which five slit-shaped uncoated portions 33a are provided at equal intervals. When the through hole 18 is arranged at the center, the diameter of the through hole 18 is D, the pitch of the uncoated portion 33a is P, the width of the uncoated portion 33a is W, the length of the uncoated portion 33a is L, and the uncoated portion 33a. Assuming that the width of the positional deviation allowed in the length direction of 2α is 2α, the through holes 18 and 19 are provided using the screen plate 30 that satisfies the relationship of D> W, D> P−W, L ≧ D + 2α. A land portion made of a conductive paste connected to the wiring pattern 12A, including a wiring pattern 12A made of a conductive paste and open end portions 18a and 19a of the through holes 18 and 19 by printing on one surface 11a of the substrate 11. Patter 14A and 15A, and the land patterns 14A and 15A are provided with slit forming areas in which five uncoated portions of the conductive paste are provided at equal intervals in the land pattern 14A and 15A. Even when the mesh region 33 is displaced, at least a part of the uncoated portion (air hole) overlaps the opening of the through holes 18 and 19, so that the uncoated portion (air hole) causes the through holes 18 and Air does not easily accumulate in the inside 19, and the conductive paste flows smoothly into the through holes 18 and 19, so that an appropriate amount of the conductive paste can be applied to the inner side surfaces of the through holes 18 and 19. Therefore, since no breakage occurs in the through wirings 20 and 21 formed by curing the conductive patterns 20A and 21A made of a conductive paste applied to the inner side surfaces of the through holes 18 and 19, the conductivity of the through wirings 20 and 21 is increased. Further improvement can be achieved.

  In this embodiment, a method of manufacturing the wiring substrate 10 is illustrated in which the coil-shaped wiring 12 is formed on one surface 11a of the substrate 11 and the linear wiring 13 is formed on the other surface 11b of the substrate 11. However, the manufacturing method of the wiring board of the present invention is not limited to this. In the method for manufacturing a wiring board according to the present invention, the shape of the wiring formed on one surface and / or the other surface of the substrate may be any shape. Further, in the method of manufacturing a wiring board according to the present invention, a wiring is formed on one of the one surface or the other surface of the substrate, and the surface on which the wiring is formed with the wiring as a base end A through wiring extending over the opposite surface may be formed, and the end of the through wiring may be exposed on the opposite surface. And you may connect the terminal of an electronic component to the edge part of the penetration wiring.

  Moreover, in this embodiment, although the case where the shape of the land part was square shape in planar view was illustrated, the manufacturing method of the wiring board of this invention is not limited to this. In the method for manufacturing a wiring board according to the present invention, the shape of the land portion may be a circular shape in plan view, an elliptical shape, or the like.

  Further, in the first embodiment of the process A, the case where the one through-holes 18 and 19 are respectively provided in the portions of the substrate 11 where the land portions 14 and 15 are formed is illustrated. In the second embodiment, the case where the three through holes 18 and 19 are respectively provided in the portions of the substrate 11 where the land portions 14 and 15 are formed is illustrated. However, the method for manufacturing the wiring substrate of the present invention is as follows. It is not limited to this. In the method for manufacturing a wiring board according to the present invention, two or four or more through holes may be provided in a portion of the substrate where the land portion is formed. Further, when a plurality of through holes corresponding to one land portion are provided, the pitch (center distance) is not particularly limited as long as the through holes are provided at equal intervals.

  Further, in this embodiment, the land pattern 14A, 15A is exemplified by the case where the slit forming region is provided in which five uncoated portions of the conductive paste are provided at equal intervals in the slit shape. The method of manufacturing the wiring board is not limited to this. In the method for manufacturing a wiring board according to the present invention, two or more uncoated portions may be provided.

DESCRIPTION OF SYMBOLS 10 ... Wiring board, 11 ... Board, 12, 13 ... Wiring, 14, 15, 16, 17 ... Land part, 18, 19 ... Through-hole, 18a, 19a ... Opening End portions 20, 21 ... through wiring, 30 ... screen plate, 31 ... screen base, 32 ... mesh region, 33, 34 ... mesh region, 33a ... uncoated portion.

Claims (1)

A board, a wiring provided on the board, a land portion connected to the wiring, and an inner side surface of the through hole of the board are electrically connected to the wiring and electrically connected to the other surface. And a through wiring for manufacturing a wiring board comprising:
On one surface of the substrate provided with at least one through-hole, the printed wiring pattern is formed of a conductive paste including the conductive paste and includes the opening end of the through-hole and connected to the wiring pattern by printing. A land portion pattern, and the land portion pattern is provided with a slit forming region in which a plurality of uncoated portions of the conductive paste are provided at equal intervals in a slit shape, thereby forming the land portion on the inner surface of the through hole. Step A of forming a conductive pattern made of a conductive paste;
The wiring pattern, the land portion pattern, and the conductive pattern are cured to form a wiring, a land portion, and a through wiring; and
In the step A, when the through hole is arranged at the center of the slit forming region, the diameter of the through hole is D, the pitch between two uncoated portions adjacent to each other among the plurality of uncoated portions is P, When the width of the coated portion is W, the length of the uncoated portion is L, and the width of the positional deviation allowed in the length direction of the uncoated portion in the land pattern is 2α, D> W, D> A method of manufacturing a wiring board, comprising: forming the land portion pattern having the slit forming region satisfying a relationship of PW, L ≧ D + 2α.

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