JP2007221077A - Connection structure and connection method for printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the connection structure of a printed wiring board for highly precisely connecting a flexible board, by preventing conductive materials from being projected to the periphery of the connection part of a bridge or connection materials even when the pitch of a terminal for connection is extremely small. <P>SOLUTION: Connection terminal 12A in a flexible substrate 10 to a corresponding connection terminal 22A in a rigid substrate 20 is joined through an adhesive sheet 30 so as to be faced to each other. A cylindrical connection conductor 31 is formed in direct contact with the connection terminal 22A of the rigid substrate 20 through the flexible substrate 10 at the central part of the corresponding pair of connection terminals 12A and 22A. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a connection structure and a connection method for printed wiring boards, and more particularly to a connection technique between connection terminal portions of a flexible printed wiring board and a counterpart printed wiring board.

  Conventionally, a method is known in which a thermosetting anisotropic conductive resin is applied to a connection portion on the side of a flexible printed wiring board and connected to a counterpart printed wiring board by thermocompression bonding (for example, see Patent Document 1).

  However, the thermosetting anisotropic conductive resin has a problem that the material cost increases because it is necessary to strictly manage the composition such as the particle size and the mixing ratio of the conductive particles to be mixed. Also, in order to ensure electrical continuity with the conductive particles, it is necessary to maintain the parallelism between the connecting terminal portions of the flexible substrate and the mating substrate with high accuracy in the joining process. As a result, the manufacturing cost increases.

  As another connection method for connecting the flexible printed wiring board and the counterpart printed wiring board, the connecting terminal portions are connected to each other by soldering, and the flexible printed wiring board is connected to the counterpart printed wiring board via an adhesive. A method of bonding is known (see, for example, Patent Document 2).

However, this connection method has a problem in that the amount of printed solder is likely to vary, and a solder bridge is likely to occur between connection terminal portions adjacent to each other at connection locations. In addition, there is a concern that the adhesive may flow out around the connecting portion during bonding.
JP 2003-297516 A JP 2005-116596 A

  In the connection between the flexible printed wiring board and the counterpart printed wiring board, even when the pitch of the connecting terminal portions is extremely small, the present invention prevents the conductive material from protruding to the periphery of the bridge or the connecting portion of the adhesive, An object of the present invention is to provide a printed wiring board connection structure and a connection method capable of connecting a flexible substrate with high accuracy.

  In the connection structure of the printed wiring board according to the present invention, a pair of printed wiring boards each having a connection terminal portion are bonded to each other with the connection terminal portions corresponding to each other by an adhesive layer, and the connection connections corresponding to each other. The terminal portions are connected by a connection conductor narrower than the width of the connection terminal portion.

  In the present invention, at least one of the pair of printed wiring boards is a flexible printed wiring board.

  Moreover, the part to which the connection conductor in the terminal part for a connection is connected may be a wide part wider than other parts.

  Further, the connection terminal portions are formed such that a plurality of the wide portions are intermittently formed along the length direction, and the wide portions of the connection terminal portions adjacent to each other are alternately arranged so as not to interfere with each other. It may be the composition which is.

  Further, the connection conductor may have a structure penetrating one of the connection terminal portions, or may have a structure interposed so as to be joined to both of the connection terminal portions.

  In the method for connecting a printed wiring board according to the present invention, the connecting terminal portion of the flexible printed wiring board is exposed at the edge portion of one surface of the insulating substrate so that the connecting terminal portion is exposed. An adhesive sheet affixing step for adhering an adhesive sheet to an area to be formed, and a mating connection terminal portion formed by exposing the flexible printed wiring board to one surface of the mating printed wiring board via the adhesive sheet A bonding step of bonding the flexible printed wiring board and the mating printed wiring board to each other, and the connecting terminal portion and the adhesive sheet from the other surface of the insulating substrate of the flexible printed wiring board An opening step for forming an opening that penetrates through to the mating connection terminal portion, a filling step for filling the opening with a conductive material to form a connection conductor, Characterized in that it comprises a curing step of curing the connecting conductors and said adhesive sheet portion where the flexible printed wiring board and a mating printed circuit board by bonding heat and pressure pressing to the.

  Further, in another connection method of the printed wiring board according to the present invention, the connection of the flexible printed wiring board in which the terminal portion for connection is exposed and arranged at the edge portion of one surface of the insulating base. An adhesive sheet attaching step of attaching an adhesive sheet to the other surface of the insulating substrate in the region where the terminal portion is exposed, and an opening reaching the connecting terminal portion from the adhesive sheet side of the flexible printed wiring board An opening step to be formed, a filling step in which a conductive material is filled into the opening to form a connection conductor, and a region in which a mating connection terminal portion is formed so as to be exposed on one surface of the mating printed wiring board Bonding the adhesive sheet and joining the connection conductor to a region within the contour of the mating printed wiring board; and the flexible printed wiring board and the mating printed wiring board The bonded portion is heated pressure press, characterized in that it comprises a curing step of curing the connecting conductors and said adhesive sheet.

  In the above-described printed wiring board connection method, the connection terminal portion and the mating connection terminal portion at the positions where the openings are formed can be wide portions wider than the openings.

  Moreover, it is preferable that the wide part formed on the same surface of the flexible printed wiring board or the mating printed wiring board is alternately arranged between adjacent ones of the connecting terminal part or the mating connecting terminal part.

  According to the present invention, the pitch of the connecting terminal portion between the flexible substrate and the counterpart substrate can be reduced, and the conductive material bridge, the adhesive sheet, the adhesive layer that forms the adhesive layer, and the like around the connection portion Protrusion can be prevented and the flexible substrate can be connected with high accuracy. In addition, by forming the wide portion in the connection terminal portion, the contact area between the connection conductor and the connection terminal can be increased, and an increase in connection resistance can be suppressed.

  Hereinafter, the details of a connection method and a connection structure of a printed wiring board according to embodiments of the present invention will be described with reference to the drawings. However, it should be noted that the drawings are schematic and the thicknesses and ratios of the material layers are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, the part from which the relationship and ratio of a mutual dimension differ also in between drawings is contained.

(First embodiment)
1 to 7 show a printed wiring board connection structure and connection method according to a first embodiment of the present invention. 1 is a plan view of a principal part of a printed wiring board connection structure according to the present embodiment, FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, and FIGS. It is sectional drawing.

"Connection structure of printed wiring board"
As shown in FIGS. 1 and 2, the printed wiring board connection structure according to the present embodiment is an example in which a flexible substrate 10 and a rigid substrate 20 are connected.

  The flexible substrate 10 includes, for example, a flexible insulating substrate (film base material) 11 made of polyimide resin, liquid crystal polymer, and the like, a plurality of wirings 12 formed on one surface of the insulating substrate, and insulating properties. Similarly to the substrate 11, a cover lay 13 made of an insulating material is provided.

  The wiring 12 is formed by patterning a copper foil on the insulating substrate 11 by, for example, a subtractive method, and a predetermined edge of the insulating substrate 11 is connected to the end of the wiring 12. The terminal portions 12A for use are arranged in parallel at a predetermined pitch. In addition, in the connection area | region a (refer FIG. 1) in which these connection terminal parts 12A in the flexible substrate 10 are arrange | positioned, the coverlay 13 does not exist so that the connection terminal part 12A may be exposed.

  The rigid substrate 20 is generally configured to include an insulating substrate (base material) 21, a plurality of wirings 22 patterned on one surface of the insulating substrate 21, and a resist layer 23.

  As a constituent material of the insulating substrate 21, for example, glass epoxy, SEM3, paper epoxy, or the like can be used.

  The wiring 22 is formed by patterning a copper foil attached on the insulating substrate 21 by, for example, a subtractive method. In addition, as copper foil, rolled copper foil, electrolytic copper foil, etc. can be used. Then, at predetermined edge portions of the insulating substrate 21, the connection terminal portions 22 </ b> A which are the end portions of these wirings 22 are parallel to the connection terminal portions 12 </ b> A of the flexible substrate 10 described above. Has been placed. In addition, the resist layer 23 does not exist in the connection area | region b in which these connection terminal parts 22A in the rigid board | substrate 20 are arrange | positioned so that 22A of connection terminal parts may be exposed.

  As the resist layer 23, the same resin as the insulating substrate 21 can be used.

  As shown in FIG. 2, in the printed wiring board connection structure according to the present embodiment, the connection region a of the flexible substrate 10 and the connection region b of the rigid substrate 20 correspond to each other. The part 12 </ b> A and the connecting terminal part 22 </ b> A are bonded to each other via the adhesive sheet 30. As shown in FIG. 1, a cylindrical connection conductor that penetrates the flexible substrate 10 and contacts the connection terminal portion 22 </ b> A of the rigid substrate 20 is provided at the center of the pair of connection terminal portions 12 </ b> A and 22 </ b> A to be joined. 31 is formed, and the connection terminal portions 12A and 22A are electrically connected to each other by the connection conductor 31. In addition, as a material of the connection conductor 31, a solder and another electroconductive material can be used.

  The adhesive sheet 30 is set to have the same size as the region c where the connection region a of the flexible substrate 10 and the connection region b of the rigid substrate 20 overlap. In the present embodiment, as the adhesive sheet 30, for example, an epoxy or acrylic thermosetting adhesive sheet is used.

  In the printed wiring board connection structure according to the present embodiment, since the connection conductor 31 is formed at the center of the connection terminal portions 12A and 22A that overlap each other, the pitch between the connection terminal portions 12A of the flexible substrate 10 and the rigid Even if the pitch between the connection terminal portions 22A of the substrate 20 is extremely small, it is possible to reliably prevent the adjacent connection terminal portions 12A or the connection terminal portions 22A from being short-circuited with the conductive material.

"Connection method of printed wiring board"
Hereinafter, the connection method of the printed wiring board according to the present embodiment will be described with reference to FIGS.

  First, as shown in FIG. 3, an adhesive sheet 30 is temporarily bonded to a region c (see FIG. 1) overlapping the rigid substrate 20 in the connection region a (see FIG. 1) of the flexible substrate 10 by, for example, a vacuum laminating method.

  Next, as shown in FIG. 4, the adhesive sheet 30 adhered to the flexible substrate 10 is aligned with a region c (see FIG. 1) that overlaps the flexible substrate 10 in the connection region b (see FIG. 1) of the rigid substrate 20. In the same manner as the flexible substrate 10, temporary bonding is performed by a vacuum laminating method. At this time, alignment is performed so that the corresponding connection terminal portions 12A and 22A of the flexible substrate 10 and the rigid substrate 20 overlap each other.

  The adhesive sheet 30 is set so as to be in a semi-cured B stage state during temporary adhesion.

  Thereafter, as shown in FIG. 5, an opening 14 having a depth reaching the connection terminal portion 22 </ b> A of the rigid substrate 20 is formed on the flexible substrate 10 side. The opening 14 is formed using, for example, a UV-YAG laser.

  Next, as shown in FIG. 6, the connection conductor 31 is formed by filling the opening 14 with a conductive material using a screen printing method or the like.

  Then, as shown in FIG. 7, the connection conductor (conductive material) 31 and the adhesive sheet 30 are cured by heating and pressurizing the connection portion between the flexible substrate 10 and the rigid substrate 20 via the cushion material 32. A printed wiring board connection structure as shown in FIG.

  As a specific example of the printed wiring board connection method according to the present embodiment, the insulating substrate (film substrate) 11 constituting the flexible substrate 10 is a polyimide substrate, and the thickness thereof is set to 25 μm, for example. ing. Moreover, the thickness of the copper foil (single-sided CCL) that forms the wiring 12 is set to 12 μm. The line / space width of the connecting terminal portion (land portion) 12A is 50 μm / 50 μm (pitch 100 μm). Moreover, the opening part 14 for filling the connection conductor 31 is a circular opening, and the diameter thereof is set to 30 μm, for example.

  The line / space width of the connecting terminal portion 22A in the rigid substrate 20 is set to 50 μm / 50 μm (pitch 100 μm).

  The adhesive sheet 30 is made of an acrylic adhesive film (for example, product name PILARAX LF, manufactured by DuPont), and has a thickness of 25 μm. In addition, as a conductive material for forming the connection conductor 31, a metal paste (Halima Chemical) was used.

Moreover, a heating and pressing press is performed at 180 kg, 1 hour, and 30 kgf / cm < ² >, for example.

(Second Embodiment)
8 to 14 show a printed wiring board connection structure and connection method according to the second embodiment of the present invention. FIG. 8 is a plan view of a principal part of the printed wiring board connection structure according to the present embodiment, FIG. 9 is a sectional view taken along line BB in FIG. 8, and FIGS. It is.

"Connection structure of printed wiring board"
As shown in FIGS. 8 and 9, the printed wiring board connection structure according to the present embodiment is an example in which a flexible substrate 10 and a rigid substrate 20 are connected. In the printed wiring board connection structure according to the present embodiment, the same parts as those in the printed wiring board connection structure according to the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. Detailed description will be omitted.

  The flexible substrate 10 includes a flexible insulating substrate 11, a plurality of wirings 12 formed on one surface of the insulating substrate, a cover lay 13 made of the same insulating material as the insulating substrate 11, It is roughly comprised with.

  The rigid substrate 20 generally includes an insulating substrate 21, a plurality of wirings 22 patterned on one surface of the insulating substrate 21, and a resist layer 23. At predetermined edge portions of the insulating substrate 21, connection terminal portions 22 </ b> A that are the end portions of these wirings 22 are arranged so as to be parallel to the connection terminal portions 12 </ b> A of the flexible substrate 10 described above. ing.

  As shown in FIG. 8, in the printed wiring board connection structure according to the present embodiment, the connection region a of the flexible substrate 10 and the connection region b of the rigid substrate 20 correspond to each other in the connection terminal portion 12A. And the connecting terminal portions 22A are opposed to each other via the adhesive sheet 30. Further, as shown in FIG. 8, the pair of connection terminal portions 12A and 22A to be joined is formed with an elongated connection conductor 31A that penetrates the flexible substrate 10 and contacts the connection terminal portion 22A of the rigid substrate 20. The connection terminal portions 12A and 22A are electrically connected to each other by the connection conductor 31A. In addition, as a material of the connection conductor 31A, solder or other conductive materials can be used. The connection conductor 31A has an elongated shape along the extending direction of the connection terminal portions 12A and 22A, the width dimension is narrower than the connection terminal portions 12A and 22A, and the length is the connection terminal portions 12A and 22A. Is set to be shorter than the length of the region c (the length in the extending direction of the connection terminal portion).

  In the printed wiring board connection structure according to the present embodiment, the area where the connection conductor 31 abuts on the connection terminal portion 22A is large, and the connection resistance can be reduced. Moreover, since the width dimension of the connection conductor 31 is set narrower than the connection terminal portions 12A and 22A, the pitch between the connection terminal portions 12A of the flexible substrate 10 and the pitch between the connection terminal portions 22A of the rigid substrate 20 are set. Even if it is extremely small, it is possible to reliably prevent the adjacent connection terminal portions 12A or the connection terminal portions 22A from being short-circuited with the conductive material.

"Connection method of printed wiring board"
As shown in FIGS. 10 to 14, the method for connecting the printed wiring boards according to the present embodiment is the same as the method described with reference to FIGS. 3 to 7 in the first embodiment. .

  In the printed wiring board connection structure of the present embodiment, the insulating substrate (film substrate) 11 constituting the flexible substrate 10 is made of a polyimide substrate, and the thickness thereof can be set to 25 μm, for example. Moreover, the thickness of the copper foil (single-sided CCL) that forms the wiring 12 is set to 12 μm. The line / space width of the connecting terminal portion (land portion) 12A is 50 μm / 50 μm (pitch 100 μm). The dimension of the opening 14A formed in the connection part of the flexible substrate 10 is a rectangular through-hole with a width of 30 μm and a length of 5 mm.

  The line / space width of the connecting terminal portion 22A in the rigid substrate 20 is set to 50 μm / 50 μm (pitch 100 μm).

  The adhesive sheet 30 is made of an acrylic adhesive film (for example, product name PILARAX LF, manufactured by DuPont), and has a thickness of 25 μm. In addition, as a conductive material for forming the connection conductor 31, a metal paste (Halima Chemical) was used.

In addition, the heating and pressing in the printed wiring board connection method according to the present embodiment is performed, for example, at 180 ° C. for 1 hour at 30 kgf / cm ² .

  In the connection structure of the printed wiring board according to the present embodiment, unlike the structure of the first embodiment described above, the connection conductor 31A has an elongated rectangular parallelepiped shape. Therefore, the rigid substrate whose conductive material paste is the counterpart substrate The area in contact with the 20 connection terminal portions 22A is large, and the connection resistance can be reduced.

(Third embodiment)
15 and 16 show a printed wiring board connection structure according to the third embodiment of the present invention. 15 is a plan view of a principal part of the printed wiring board connection structure according to the present embodiment, and FIG. 16 is a cross-sectional view taken along the line CC of FIG.

  As shown in FIGS. 15 and 16, the printed wiring board connection structure according to the present embodiment is an example in which a flexible substrate 10 and a rigid substrate 20 are connected. In the printed wiring board connection structure according to the present embodiment, the same parts as those in the printed wiring board connection structure according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The printed wiring board connection structure according to the present embodiment differs from the printed wiring board connection structure according to the first embodiment in the following points. That is, the different point of this embodiment is that a plurality of connection conductors 31 are provided along the longitudinal direction. As shown in FIGS. 15 and 16, a pair of connection terminal portions 12 </ b> A and 22 </ b> A to be joined has a columnar connection conductor 31 </ b> A that penetrates the flexible substrate 10 and contacts the connection terminal portion 22 </ b> A of the rigid substrate 20. Three are provided at equal intervals along the longitudinal direction (extending direction of the connecting terminal portion 12A).

  Note that other configurations and connection methods in the present embodiment are the same as those in the first embodiment described above, and a description thereof will be omitted.

  In the printed wiring board connection structure according to the present embodiment, since three connection conductors 31 are provided, the entire contact conductor 31 has a large area in contact with the connection terminal portion 22A, and the connection resistance can be reduced. it can. Moreover, since the width dimension of the connection conductor 31 is set narrower than the connection terminal portions 12A and 22A, the pitch between the connection terminal portions 12A of the flexible substrate 10 and the pitch between the connection terminal portions 22A of the rigid substrate 20 are set. Even if it is extremely small, it is possible to reliably prevent the adjacent connection terminal portions 12A or the connection terminal portions 22A from being short-circuited with the conductive material.

(Fourth embodiment)
17 to 23 show a printed wiring board connection structure and connection method according to the fourth embodiment of the present invention. FIG. 17 is a plan view of a principal part of the printed wiring board connection structure according to the present embodiment, FIG. 18 is a sectional view taken along the line DD in FIG. 17, and FIGS. It is sectional drawing.

"Connection structure of printed wiring board"
As shown in FIGS. 17 and 18, the printed wiring board connection structure according to the present embodiment is an example in which a flexible substrate 40 and a rigid substrate 50 are connected.

  The flexible substrate 40 includes, for example, a flexible insulating substrate (film base material) 41 made of polyimide resin, liquid crystal polymer, or the like, a plurality of wirings 42 formed on one surface of the insulating substrate, and insulating properties. Similarly to the substrate 41, a cover lay 43 made of an insulating material is provided.

  The wiring 42 is formed by patterning a copper foil on the insulating substrate 41 by, for example, a subtractive method. Then, at predetermined end edges of the insulating substrate 41, connection terminal portions 42A that are end portions of these wirings 42 are arranged in parallel at a predetermined pitch. In the connection region a where the connection terminal portions 42A are arranged on the flexible substrate 40, the coverlay 43 does not exist so that the connection terminal portions 42A are exposed.

  The rigid substrate 50 is generally configured to include an insulating substrate (base material) 51, a plurality of wirings 52 patterned on one surface of the insulating substrate 51, and a resist layer 53.

  As a constituent material of the insulating substrate 51, for example, glass epoxy, SEM3, paper epoxy, or the like can be used.

  The wiring 52 is formed by patterning the copper foil on the insulating substrate 51 by, for example, a subtractive method. In addition, as copper foil, rolled copper foil, electrolytic copper foil, etc. can be used. Then, at predetermined edge portions of the insulating substrate 51, the connection terminal portions 52 </ b> A that are the end portions of the wirings 52 are parallel to the connection terminal portions 42 </ b> A of the flexible substrate 40 described above. Has been placed. Note that the resist layer 53 does not exist in the connection region b in the rigid substrate 50 where the connection terminal portions 52A are disposed so that the connection terminal portions 52A are exposed.

  As the resist layer 53, the same resin as the insulating substrate 51 can be used.

  In the present embodiment, as shown in FIG. 17, the connection terminal portions 42 </ b> A and the connection terminal portions 52 </ b> A that correspond to each other are bonded to each other via the insulating substrate 41 and the adhesive sheet 30. That is, in the present embodiment, the insulating substrate 41 is joined so as to be positioned between the connecting terminal portion 42A and the connecting terminal portion 52A. Further, as shown in FIG. 18, between the central portions of the pair of connection terminal portions 42 </ b> A and 52 </ b> A to be connected, the adhesive sheet 30 and the insulating substrate 41 are penetrated to connect the connection terminal portions of the rigid substrate 50. A cylindrical connection conductor 31B that abuts on 52A is formed, and the connection terminal portions 42A and 52A are electrically connected to each other by the connection conductor 31B. In addition, as a material of the connection conductor 31B, solder or other conductive materials can be used.

  The adhesive sheet 30 is set to the same size as a region c (see FIG. 17) where the connection region a of the flexible substrate 40 and the connection region b of the rigid substrate 50 overlap. In the present embodiment, as the adhesive sheet 30, for example, an epoxy or acrylic thermosetting adhesive sheet is used.

  In the printed wiring board connection structure according to the present embodiment, even if the pitch between the connection terminal portions 42A of the flexible substrate 40 and the pitch between the connection terminal portions 52A of the rigid substrate 50 are extremely small, the adjacent connection portions are connected. It is possible to reliably prevent the terminal portions 42A or the connection terminal portions 52A from being short-circuited with the conductive material.

"Connection method of printed wiring board"
The printed wiring board connection method according to the present embodiment will be described below with reference to FIGS.

  First, as shown in FIG. 19, the adhesive sheet 30 is temporarily bonded to a region c overlapping the rigid substrate 50 in the connection region a of the flexible substrate 40 by, for example, a vacuum laminating method.

  Next, as shown in FIG. 20, an opening 44 that is a non-through hole that exposes the central portion of the connection terminal portion 42 </ b> A from the side of the adhesive sheet 30 bonded to the flexible substrate 40 is formed using, for example, a UV-YAG laser. Form.

  After that, as shown in FIG. 21, the connection conductor 31B is formed by filling the opening 44 with a conductive material using a screen printing method or the like.

  Next, as shown in FIG. 22, the connecting terminal portion 42 </ b> A and the connecting terminal portion 52 </ b> A are positioned so as to face each other, and a flexible substrate is formed at the center of the connecting terminal portion 52 </ b> A exposed in the connection region b of the rigid substrate 20. Temporary bonding is performed so that 40 connection conductors 31B are arranged. The adhesive sheet 30 is set so as to be in a semi-cured B stage state during temporary adhesion.

  Then, as shown in FIG. 23, the connection conductor (conductive material) 31 </ b> B and the adhesive sheet 30 are cured by heating and pressurizing the connection portion between the flexible substrate 40 and the rigid substrate 50 through the cushion material 32. A printed wiring board connection structure as shown in FIG. 18 can be obtained.

  As a specific example of the printed wiring board connection method according to the present embodiment, the insulating substrate (film substrate) 41 constituting the flexible substrate 40 is a polyimide substrate, and the thickness thereof is set to 25 μm, for example. ing. Further, the thickness of the copper foil (single-sided CCL) forming the wiring 42 is set to 12 μm. The line / space width of the connecting terminal portion (land portion) 42A is 50 μm / 50 μm (pitch 100 μm). The opening 44 for filling the connection conductor 31B is a circular opening, and the diameter thereof is set to 30 μm, for example.

  The line / space width of the connecting terminal portion 52A in the rigid substrate 50 is set to 50 μm / 50 μm (pitch 100 μm).

  The adhesive sheet 30 is made of an acrylic adhesive film (for example, product name PILARAX LF, manufactured by DuPont), and has a thickness of 25 μm. Further, a metal paste (harima chemical) was used as a conductive material for forming the connection conductor 31B.

Moreover, a heating and pressing press is performed at 180 kg, 1 hour, and 30 kgf / cm < ² >, for example.

(Fifth embodiment)
24 and 25 show a printed wiring board connection structure according to the fifth embodiment of the present invention. 24 is a plan view of a principal part of the printed wiring board connection structure according to the present embodiment, and FIG. 25 is a cross-sectional view taken along line EE in FIG.

  As shown in FIGS. 24 and 25, the printed wiring board connection structure according to the present embodiment is an example in which a flexible substrate 40 and a rigid substrate 50 are connected, and the printed circuit according to the above-described fourth embodiment. This is almost the same as the wiring board connection structure. The difference is that the connection conductor 31C has an elongated rectangular parallelepiped shape along the extending direction of the connection terminal portion 42A. In this embodiment, the shape is a rectangular parallelepiped. Note that other configurations in the present embodiment are the same as those in the above-described fourth embodiment, and thus description thereof is omitted.

  In the printed wiring board connection structure of the present embodiment, the insulating substrate (film substrate) 41 constituting the flexible substrate 40 is made of a polyimide substrate, and the thickness thereof can be set to 25 μm, for example. Further, the thickness of the copper foil (single-sided CCL) forming the wiring 42 is set to 12 μm. The line / space width of the connecting terminal portion (land portion) 42A is 50 μm / 50 μm (pitch 100 μm). The dimensions of the connection conductor 31C are a width (30 μm), a length (5 mm), and a height (the height of about 50 μm) of the adhesive sheet 30 and the insulating substrate 41.

  The line / space width of the connecting terminal portion 52A in the rigid substrate 50 is set to 50 μm / 50 μm (pitch 100 μm).

  The adhesive sheet 30 is made of an acrylic adhesive film (for example, product name PILARAX LF, manufactured by DuPont), and has a thickness of 25 μm. In addition, a metal paste (Halima Chemical) was used as a conductive material for forming the connection conductor 31C.

In addition, the heating and pressing in the printed wiring board connection method according to the present embodiment is performed, for example, at 180 ° C. for 1 hour at 30 kgf / cm ² .

  In the printed wiring board connection structure according to the present embodiment, the area where the connection conductor 31C abuts on the connection terminal portion 42A and the connection terminal portion 52A is large, and the connection resistance can be reduced. Further, since the width dimension of the connection conductor 31C is set narrower than the connection terminal portions 42A and 52A, the pitch between the connection terminal portions 42A of the flexible substrate 40 and the pitch between the connection terminal portions 52A of the rigid substrate 50 are set. Even if it is extremely small, it is possible to reliably prevent the adjacent connection terminal portions 42A or the connection terminal portions 52A from being short-circuited by the conductive material.

  Further, the connection method of the printed wiring board according to the present embodiment is the same as that of the above-described fourth embodiment, and thus description thereof is omitted.

(Sixth embodiment)
26 and 27 show a printed wiring board connection structure according to the sixth embodiment of the present invention. FIG. 26 is a plan view of a principal part of the printed wiring board connection structure according to the present embodiment, and FIG. 27 is a cross-sectional view taken along line FF in FIG.

  As shown in FIGS. 26 and 27, the printed wiring board connection structure according to the present embodiment is an example in which a flexible substrate 40 and a rigid substrate 50 are connected, and the printed circuit according to the fourth embodiment described above. This is almost the same as the wiring board connection structure. The difference is that there are a plurality (three) of cylindrical connection conductors 31B, which are arranged at intervals along the extending direction of the connection terminal portion 42A. Note that other configurations and connection methods in the present embodiment are the same as those in the fourth embodiment described above, and a description thereof will be omitted.

  In the printed wiring board connection structure according to the present embodiment, since there are a plurality of connection conductors 31B, the area of contact with the connection terminal portion 42A and the connection terminal portion 52A is large, and the connection resistance can be reduced. Even if the pitch between the connection terminal portions 42A of the flexible substrate 40 and the pitch between the connection terminal portions 52A of the rigid substrate 50 are extremely small, the adjacent connection terminal portions 42A or the connection terminal portions 52A are adjacent to each other. Can be reliably prevented from being short-circuited by the conductive material.

(Seventh embodiment)
28 to 34 show a printed wiring board connection structure and connection method according to a seventh embodiment of the present invention. 28 is a plan view of a principal part of the connection structure of the printed wiring board according to the present embodiment, FIG. 29 is a sectional view taken along the line GG of FIG. 28, and FIGS. It is sectional drawing.

"Connection structure of printed wiring board"
As shown in FIGS. 28 and 29, the printed wiring board connection structure according to the present embodiment is an example in which a flexible substrate 60 and a rigid substrate 70 are connected, and the end portion of the connection terminal portion is enormously circular. It has a characteristic shape.

  The flexible substrate 60 includes a flexible insulating substrate (film base material) 61 made of, for example, polyimide resin or liquid crystal polymer, a plurality of wirings 62 formed on one surface of the insulating substrate, and insulating properties. And a cover lay 63 made of the same material as that of the substrate 61.

  The wiring 62 is formed by patterning the copper foil on the insulating substrate 61 by, for example, a subtractive method. As shown in FIG. 28, connecting terminal portions 62A, which are the end portions of these wirings 62, are arranged at predetermined end edges of the insulating substrate 61 so as to be parallel at a predetermined pitch. In addition, the end portions of the connection terminal portions 62A are alternately arranged. That is, the connecting terminal portion 62A is alternately arranged such that the terminal portion extending to the end edge of the insulating substrate 61 and the terminal portion located on the inner side from the end edge of the insulating substrate 61 are arranged. The parts are arranged in a staggered pattern. Furthermore, a circular wide portion 62B having a diameter longer than the width of the connecting terminal portion 62A is integrally formed at the end portion of the connecting terminal portion 62A. The center of the wide portion 62B is located on the extension of the center line of the connection terminal portion 62A. In the connection region where the connection terminal portions (including the wide portion 62B) 62A are arranged on the flexible substrate 60, the coverlay 63 does not exist so that the connection terminal portion 62A is exposed.

  The rigid substrate 70 is generally configured to include an insulating substrate (base material) 71, a plurality of wirings 72 patterned on one surface of the insulating substrate 71, and a resist layer 73.

  As a constituent material of the insulating substrate 71, for example, glass epoxy, SEM3, paper epoxy, or the like can be used.

  The wiring 72 is formed by patterning a copper foil on the insulating substrate 71 by, for example, a subtractive method. In addition, as copper foil, rolled copper foil, electrolytic copper foil, etc. can be used. In the vicinity of the end portion of the insulating substrate 71, the connection terminal portions 72 </ b> A of these wirings 72 are arranged in parallel with each other at the same pitch as the connection terminal portions 62 </ b> A of the flexible substrate 60 described above. And the wide part 72B of the shape similar to the wide part 62B of the flexible substrate 60 is formed in the edge part of these connection terminal parts 72A.

  In the present embodiment, as shown in FIG. 28 and FIG. 29, the wide portions 62 </ b> B and the wide portions 72 </ b> B that correspond to each other are joined together via the adhesive sheet 30. Between the central portions of the pair of wide portions 62B and 72B to be connected, a columnar connection conductor 31C that penetrates the adhesive sheet 30 and the insulating substrate 61 and contacts the wide portion 72B of the rigid substrate 70 is formed. The connection terminal portions 62A and 72A are electrically connected to each other by the connection conductor 31C. In addition, as a material of the connection conductor 31C, solder or other conductive materials can be used.

  In the printed wiring board connection structure according to the present embodiment, since the wide portion 62B of the flexible substrate 60 and the wide portion 72B of the rigid substrate 70 are arranged in a staggered manner, the area connected by the connection conductor 31C is increased. In addition, even if the pitch between the connection terminal portions 62A of the flexible substrate 60 and the pitch between the connection terminal portions 72A of the rigid substrate 70 are extremely small, the connection terminal portions 62A adjacent to each other or the connection terminal portions 72A. It is possible to reliably prevent a short circuit between the conductive materials.

"Connection method of printed wiring board"
Next, a printed wiring board connection method according to the present embodiment will be described with reference to FIGS.

  First, as shown in FIG. 30, the adhesive sheet 30 is temporarily bonded to a region overlapping the rigid substrate 70 in the connection region of the flexible substrate 60 by, for example, a vacuum laminating method.

  Next, as shown in FIG. 31, an opening 45, which is a non-through hole that exposes the central portion of the wide portion 62B from the side of the adhesive sheet 30 adhered to the flexible substrate 60, is formed using, for example, a UV-YAG laser. .

  After that, as shown in FIG. 32, the connection conductor 31C is formed by filling the opening 45 with a conductive material using a screen printing method or the like.

  Next, as shown in FIG. 33, after positioning so that the wide part 62B of the connecting terminal part 62A and the wide part 72B of the connecting terminal part 72A face each other, temporary bonding is performed. The adhesive sheet 30 is set so as to be in a semi-cured B stage state during temporary adhesion.

  Then, as shown in FIG. 34, the connection portion between the flexible substrate 60 and the rigid substrate 70 is heated and pressurized through the cushion material 32 to cure the connection conductor (conductive material) 31C and the adhesive sheet 30. A printed wiring board connection structure as shown in FIG. 29 can be obtained.

  In addition, as a specific example of the printed wiring board connection method according to the present embodiment, the insulating substrate (film substrate) 61 constituting the flexible substrate 60 is a polyimide substrate, and the thickness thereof is set to 25 μm, for example. ing. Moreover, the thickness of the copper foil (single-sided CCL) forming the wiring 62 is set to 12 μm. The line / space width of the connecting terminal portion (land portion) 62A is 50 μm / 50 μm (pitch 100 μm). The diameter of the wide portion 62B is 100 μm, and the opening 45 for filling the connection conductor 31C is a circular opening, and the diameter is set to 70 μm, for example. The connection conductor 31B is preferably arranged at the center in the width direction of the connection terminal portions 42A and 52A. In this case, 10 μm each from the both edges in the width direction of the connection terminal portions 42A and 52A to the connection conductor 31C. Is in the distance.

  The line / space width of the connecting terminal portion 52A in the rigid substrate 50 is set to 50 μm / 50 μm (pitch 100 μm). The diameter of the wide portion 72B is set to 100 μm.

  The adhesive sheet 30 is made of an acrylic adhesive film (for example, product name PILARAX LF, manufactured by DuPont), and has a thickness of 25 μm. Further, a metal paste (harima chemical) was used as a conductive material for forming the connection conductor 31B.

Moreover, a heating and pressing press is performed at 180 kg, 1 hour, and 30 kgf / cm < ² >, for example.

(Eighth embodiment)
35 to 42 show a printed wiring board connection structure and connection method according to an eighth embodiment of the present invention. 35 is a plan view of a principal part of the printed wiring board connection structure according to the present embodiment, FIG. 36 is a cross-sectional view taken along the line H-H in FIG. 35, and FIGS. It is.

"Connection structure of printed wiring board"
As shown in FIGS. 35 and 36, the printed wiring board connection structure according to the present embodiment is an example in which a flexible substrate 60 and a rigid substrate 70 are connected, and the end portion of the connection terminal portion is enormously circular. It has a characteristic shape.

  The flexible substrate 60 includes a flexible insulating substrate (film base material) 61 made of, for example, polyimide resin or liquid crystal polymer, a plurality of wirings 62 formed on one surface of the insulating substrate, and insulating properties. And a cover lay 63 made of the same material as that of the substrate 61.

  The wiring 62 is formed by patterning the copper foil on the insulating substrate 61 by, for example, a subtractive method. As shown in FIG. 35, connecting terminal portions 62A, which are the end portions of these wirings 62, are arranged at predetermined end edges of the insulating substrate 61 so as to be parallel at a predetermined pitch. In addition, the end portions of the connection terminal portions 62A are alternately arranged. That is, the connecting terminal portion 62A is alternately arranged such that the terminal portion extending to the end edge of the insulating substrate 61 and the terminal portion located on the inner side from the end edge of the insulating substrate 61 are arranged. The parts are arranged in a staggered pattern. Then, in the connection terminal portion 62A that extends to the edge of the insulating substrate 61, three circular wide portions 62B including the end portions are formed at equal intervals. In addition, in the connection terminal portion 62A adjacent to the connection terminal portion 62A having the three wide portions 62B as described above, two circular wide portions 62B including the end portions are formed. As shown in FIG. 35, these wide portions 62B are arranged so as to be staggered. Further, the centers of the plurality of wide portions 62B formed in the respective connection terminal portions 62A are positioned on the extension of the center line of the connection terminal portion 62A. In the connection region where the connection terminal portions (including the wide portion 62B) 62A are arranged on the flexible substrate 60, the coverlay 63 does not exist so that the connection terminal portion 62A is exposed.

  The rigid substrate 70 is generally configured to include an insulating substrate (base material) 71, a plurality of wirings 72 patterned on one surface of the insulating substrate 71, and a resist layer 73.

  As a constituent material of the insulating substrate 71, for example, glass epoxy, SEM3, paper epoxy, or the like can be used.

  The wiring 72 is formed by patterning a copper foil on the insulating substrate 71 by, for example, a subtractive method. In addition, as copper foil, rolled copper foil, electrolytic copper foil, etc. can be used. In the vicinity of the end portion of the insulating substrate 71, the connection terminal portions 72 </ b> A of these wirings 72 are arranged in parallel with each other at the same pitch as the connection terminal portions 62 </ b> A of the flexible substrate 60 described above. And the wide part 72B of the shape similar to the wide part 62B of the flexible substrate 60 is formed in the edge part of these connection terminal parts 72A. Note that the connection terminal portion 72A has three wide portions 72B formed in accordance with the corresponding connection terminal portions 62A of the flexible substrate 60 and two wide portions 72B are alternately arranged.

  In the present embodiment, as shown in FIGS. 35 and 36, the connection terminal portions 62 </ b> A and 72 </ b> A corresponding to each other are bonded to each other via the adhesive sheet 30. Between the pair of wide portions 62B and 72B to be connected, a cylindrical connection conductor 31D that penetrates the adhesive sheet 30 and the insulating substrate 61 and contacts the wide portion 72B of the rigid substrate 70 is formed. The connection terminal portions 62A and 72A are electrically connected by the conductor 31D. In addition, as a material of the connection conductor 31C, solder or other conductive materials can be used.

  In the printed wiring board connection structure according to the present embodiment, the wide portions 62B of the flexible substrate 60 and the wide portions 72B of the rigid substrate 70 are alternately arranged so as not to contact in the width direction of the connection terminal portions (62A, 72A). Therefore, even if the pitch between the connection terminal portions 62A of the flexible substrate 60 and the pitch between the connection terminal portions 72A of the rigid substrate 70 are extremely small, the connection terminal portions 62A adjacent to each other or the connection terminals It is possible to reliably prevent the portions 72A from being short-circuited with the conductive material. Since the connecting terminal portion 62A and the connecting terminal portion 72A are connected at a plurality of locations by the thick connecting conductor 31C connecting the wide portion 62B and the wide portion 72B, an increase in connection resistance can be suppressed.

"Connection method of printed wiring board"
Next, in the printed wiring board connection method according to the present embodiment, as shown in FIGS. 37 to 41, the printed wiring board as shown in FIG. 29 is used in the same manner as in the seventh embodiment. The connection structure can be obtained.

  In addition, as a specific example of the printed wiring board connection method according to the present embodiment, the insulating substrate (film substrate) 61 constituting the flexible substrate 60 is a polyimide substrate, and the thickness thereof is set to 25 μm, for example. ing. Moreover, the thickness of the copper foil (single-sided CCL) forming the wiring 62 is set to 12 μm. The line / space width of the connecting terminal portion (land portion) 62A is 50 μm / 50 μm (pitch 100 μm). The diameter of the wide portion 62B is 100 μm, and the opening 45 for filling the connection conductor 31C is a circular opening, and the diameter is set to 70 μm, for example. The connection conductor 31B is disposed at the center in the width direction of the connection terminal portions 42A and 52A, and is 10 μm from each edge in the width direction of the connection terminal portions 42A and 52A to the connection conductor 31C. is there.

  The line / space width of the connecting terminal portion 52A in the rigid substrate 50 is set to 50 μm / 50 μm (pitch 100 μm). The diameter of the wide portion 72B is set to 100 μm.

  The adhesive sheet 30 is made of an acrylic adhesive film (for example, product name PILARAX LF, manufactured by DuPont), and has a thickness of 25 μm. Further, a metal paste (harima chemical) was used as a conductive material for forming the connection conductor 31B.

Moreover, a heating and pressing press is performed at 180 kg, 1 hour, and 30 kgf / cm < ² >, for example.

It is a principal part top view of the connection structure of the printed wiring board which concerns on the 1st Embodiment of this invention. It is AA sectional drawing of FIG. It is process sectional drawing which shows the connection method of the printed wiring board which concerns on the 1st Embodiment of this invention. It is process sectional drawing which shows the connection method of the printed wiring board which concerns on the 1st Embodiment of this invention. It is process sectional drawing which shows the connection method of the printed wiring board which concerns on the 1st Embodiment of this invention. It is process sectional drawing which shows the connection method of the printed wiring board which concerns on the 1st Embodiment of this invention. It is process sectional drawing which shows the connection method of the printed wiring board which concerns on the 1st Embodiment of this invention. It is a principal part top view which shows the connection structure of the printed wiring board which concerns on the 2nd Embodiment of this invention. It is BB sectional drawing of FIG. It is process sectional drawing which shows the connection method of the printed wiring board which concerns on the 2nd Embodiment of this invention. It is process sectional drawing which shows the connection method of the printed wiring board which concerns on the 2nd Embodiment of this invention. It is process sectional drawing which shows the connection method of the printed wiring board which concerns on the 2nd Embodiment of this invention. It is process sectional drawing which shows the connection method of the printed wiring board which concerns on the 2nd Embodiment of this invention. It is process sectional drawing which shows the connection method of the printed wiring board which concerns on the 2nd Embodiment of this invention. It is a principal part top view which shows the connection structure of the printed wiring board which concerns on the 3rd Embodiment of this invention. It is CC sectional drawing of FIG. It is a principal part top view which shows the connection structure of the printed wiring board which concerns on the 4th Embodiment of this invention. It is DD sectional drawing of FIG. It is process sectional drawing which shows the connection method of the printed wiring board which concerns on the 4th Embodiment of this invention. It is process sectional drawing which shows the connection method of the printed wiring board which concerns on the 4th Embodiment of this invention. It is process sectional drawing which shows the connection method of the printed wiring board which concerns on the 4th Embodiment of this invention. It is process sectional drawing which shows the connection method of the printed wiring board which concerns on the 4th Embodiment of this invention. It is process sectional drawing which shows the connection method of the printed wiring board which concerns on the 4th Embodiment of this invention. It is a principal part top view which shows the connection structure of the printed wiring board which concerns on the 5th Embodiment of this invention. It is EE sectional drawing of FIG. It is a principal part top view which shows the connection structure of the printed wiring board which concerns on the 6th Embodiment of this invention. It is FF sectional drawing of FIG. It is a principal part top view which shows the connection structure of the printed wiring board which concerns on the 7th Embodiment of this invention. It is GG sectional drawing of FIG. It is process sectional drawing which shows the connection method of the printed wiring board which concerns on the 7th Embodiment of this invention. It is process sectional drawing which shows the connection method of the printed wiring board which concerns on the 7th Embodiment of this invention. It is process sectional drawing which shows the connection method of the printed wiring board which concerns on the 7th Embodiment of this invention. It is process sectional drawing which shows the connection method of the printed wiring board which concerns on the 7th Embodiment of this invention. It is process sectional drawing which shows the connection method of the printed wiring board which concerns on the 7th Embodiment of this invention. It is a principal part top view which shows the connection structure of the printed wiring board which concerns on the 8th Embodiment of this invention. It is HH sectional drawing of FIG. It is process sectional drawing which shows the connection method of the printed wiring board which concerns on the 8th Embodiment of this invention. It is process sectional drawing which shows the connection method of the printed wiring board which concerns on the 8th Embodiment of this invention. It is process sectional drawing which shows the connection method of the printed wiring board which concerns on the 8th Embodiment of this invention. It is process sectional drawing which shows the connection method of the printed wiring board which concerns on the 8th Embodiment of this invention. It is process sectional drawing which shows the connection method of the printed wiring board which concerns on the 8th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Flexible substrate, 11 Insulating substrate, 12 Wiring, 12A Connection terminal part, 13 Coverlay, 14 Opening part, 14A Opening part, 20 Rigid board, 21 Insulating board, 22 Wiring, 22A Connecting terminal part, 23 resist Layer, 30 Adhesive sheet, 31, 31A, 31B, 31C, 31D Connection conductor, 32 Cushion material, 40 Flexible substrate, 41 Insulating substrate, 42 Wiring, 42A Connection terminal portion, 43 Coverlay, 44, 45, 46 opening Part, 50 rigid board, 51 insulating board, 52 wiring, 52A connection terminal part, 53 resist layer,
60 flexible substrate, 61 insulating substrate, 62 wiring, 62A connecting terminal portion, 62B wide portion, 63 cover lay, 70 rigid substrate, 71 insulating substrate, 72 wiring, 72A connecting terminal portion, 72B wide portion, 73 resist layer

Claims (10)

A pair of printed wiring boards each having a connection terminal part, the connection terminal parts corresponding to each other are bonded through an adhesive layer,
The connection structure of a printed wiring board, wherein the connection terminal portions corresponding to each other are connected by a connection conductor narrower than a width of the connection terminal portion.   The printed wiring board connection structure according to claim 1, wherein at least one of the pair of printed wiring boards is a flexible printed wiring board.   The connection part of the printed wiring board according to claim 1 or 2, wherein a part of the connection terminal part to which the connection conductor is connected is a wide part wider than the other part. Construction.   A plurality of the wide portions are intermittently formed along the length direction of the connection terminal portions, and the wide portions of the connection terminal portions adjacent to each other are alternately arranged so as not to interfere with each other. The printed wiring board connection structure according to claim 3.   5. The print according to claim 1, wherein the connection conductor passes through one of the connection terminal portions opposed to each other. Wiring board connection structure.   5. The connection of a printed wiring board according to claim 1, wherein the connection conductor is interposed so as to be joined to both of the connection terminal portions facing each other. 6. Construction. Adhesive sheet pasting step of adhering an adhesive sheet to an area where the connecting terminal portion of the flexible printed wiring board is exposed at the edge portion of one surface of the insulating base material. When,
Bonding the flexible printed wiring board to the region where the mating connection terminal portion arranged exposed on one surface of the counterpart printed wiring board is formed via the adhesive sheet, and the flexible printed wiring board A bonding step of bonding the mating printed wiring board;
An opening that exposes the region in the outline of the terminal portion for connection and the region in the outline of the terminal portion for connection through the adhesive sheet from the other surface of the insulating base of the flexible printed wiring board. An opening step to be formed;
A filling step of filling the opening with a conductive material to form a connection conductor;
A curing step of curing the connection conductor and the adhesive sheet by pressing the portion where the flexible printed wiring board and the mating printed wiring board are joined together by heating and pressing;
A method of connecting a printed wiring board, comprising: The other end of the insulating substrate in the region where the connecting terminal portion of the flexible printed wiring board is exposed at the edge portion of the one surface of the insulating substrate and the connecting terminal portion is exposed. An adhesive sheet attaching process for attaching an adhesive sheet to the surface;
An opening step of forming an opening so that a region within the outline of the connection terminal portion is exposed from the adhesive sheet side of the flexible printed wiring board;
A filling step of filling the opening with a conductive material to form a connection conductor;
The adhesive sheet is bonded to the region where the mating connection terminal portion arranged exposed on one surface of the mating printed wiring board is bonded, and the connection conductor is placed in a region within the contour of the mating printed wiring board. Joining process to join,
A curing step of curing the connection conductor and the adhesive sheet by pressing the portion where the flexible printed wiring board and the mating printed wiring board are joined together by heating and pressing;
A method of connecting a printed wiring board, comprising:   9. The connection terminal portion and the counterpart connection terminal portion at a position where the opening is formed are formed in a wide portion wider than the opening. The printed wiring board connection method described.   10. The printed wiring according to claim 9, wherein the wide portions formed on the same surface are alternately arranged between the connection terminal portions or the counterpart connection terminal portions adjacent to each other. Board connection method.

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