JP2010028051A - Method of manufacturing multilayered printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a multilayered printed wiring board capable of providing a multilayered printed wiring board to reduce a resistance value between substrate sheets with conductive bumps sandwiching a nonconductive sheet and connected to each other through the conductive bumps smashing into the nonconductive sheet. <P>SOLUTION: In manufacturing the multilayered printed wiring board 50, recessed parts 12 are first previously formed at respective parts at which the respective conductive bumps 14 should be formed in the substrate sheet 10. The conductive bumps 14 are formed on the respective recessed parts 12 of the substrate sheet 10, thereafter the substrate sheet 10 with the conductive bumps 14 and the nonconductive sheet 40 are superposed on each other, and the respective recessed parts 12 of the substrate sheet 10 with the conductive bumps 14 formed thereon are each deformed into a projecting part 16 when sandwiching and pressing the superposed body. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a multilayer printed wiring board manufacturing method for manufacturing a multilayer printed wiring board.

  Conventionally, a substrate sheet with conductive bumps, in which a plurality of substantially conical conductive bumps are formed on the surface of a substrate sheet such as copper foil, and a non-conductive sheet (insulating sheet) such as a prepreg are alternately stacked. A multilayer printed wiring board formed by this method is known. In such a multilayer printed wiring board, when the conductive bump formed on the surface of the substrate sheet penetrates the insulating sheet, the substrate sheets on both sides of the insulating sheet are electrically connected by the conductive bump. (See, for example, Patent Documents 1 to 3).

  A method for forming the substrate sheet with conductive bumps will be described with reference to FIGS. In forming a plurality of conductive bumps on the substrate sheet, a screen printing method (stencil printing method) using a screen plate 92 made of, for example, a metal mask plate and a squeegee 96 is used.

  Specifically, first, a flat substrate sheet 80 as shown in FIG. 13 is placed on a printing surface plate 90, and a screen plate 92 is placed above the flat substrate sheet 80 with a slight distance therebetween. Install. At this time, the screen plate 92 is aligned with the substrate sheet 80 placed on the printing surface plate 90 by a CCD camera (not shown) or the like, and both ends of the screen plate 92 are held by the holding members 94. Hold. Further, as shown in FIG. 14, the screen plate 92 has a plurality of through holes (plate holes) 92 a corresponding to positions where the conductive bumps 82 are to be formed on the substrate sheet 80. Then, as shown in FIGS. 13 and 14, the conductive paste 98 is applied with the squeegee 96. At this time, the squeegee 96 presses the screen plate 92 downward as shown in FIG. And the substrate sheet 80 are brought into contact with each other, the conductive paste 98 passes through the through hole 92 a of the screen plate 92 and adheres to the flat substrate sheet 80.

  Here, the principle of applying the conductive paste 98 via the screen plate 92 by the squeegee 96 will be described in more detail. The conductive paste 98 is moved along the surface of the screen plate 92 by the squeegee 96. In a portion where the through hole 92a is formed in 92, the conductive paste 98 enters the through hole 92a. Then, as shown in FIG. 14, when the squeegee 96 presses the screen plate 92 toward the substrate sheet 80, a part of the conductive paste 98 that has entered the through hole 92 a adheres onto the substrate sheet 80. .

  After the conductive paste 98 is adhered on the substrate sheet 80 by the screen printing method using the squeegee 96, the substrate sheet 80 is dried. As a result, as shown in FIG. 15, the conductive paste 98 on the substrate sheet 80 is thermally cured to form a substantially conical conductive bump 82.

  Here, the conductive bumps 82 formed on the substrate sheet 80 need to be high enough to penetrate an insulating sheet (not shown) in the thickness direction of the substrate sheet 80 (vertical direction in FIG. 15). It is said. In addition, when the fine pitch of the multilayer printed wiring board is to be achieved, the substantially conical conductive bump 82 has a shape that reduces the bottom area even at the same height, that is, a substantially conical shape having a high aspect ratio. It is necessary to make it.

  Further, as another screen printing method, for example, the one shown in Patent Document 4 is known. In the screen printing method disclosed in Patent Document 4, pastes are transferred only to the vertices of convex portions of a printed board having a concavo-convex surface. Specifically, an elastic roll formed of rubber or a soft resin is interposed between the screen plate and the printing substrate, the paste on the screen plate is once transferred to the elastic roll, and the elastic roll is rotated while the elastic roll is rotated. The paste transferred to the elastic roll is transferred to the apex of the convex portion of the printing substrate.

Japanese Patent No. 3167840 JP-A-6-342977 JP 2002-305376 A JP 2004-268266 A

  However, in the conventional method of manufacturing a substrate sheet with conductive bumps, when forming the conductive bumps 82 on the flat substrate sheet 80, the conductive paste 98 attached to the substrate sheet 80 per screen printing step. Is determined by the through hole 92a of the screen plate 92, the amount of the conductive paste 98 is not sufficient, and the height of the conductive bump 82 is sufficient to penetrate the insulating sheet in one screen printing process. Often does not reach the height. Describing in more detail with reference to the drawings, FIGS. 15A to 15D are views showing a process in which the conductive bumps 82 are formed on the substrate sheet 80 by a conventional method. FIG. The shape of the conductive bump 82 after the second screen printing step and the drying step is shown, and (b) shows the shape of the conductive bump 82 after the second screen printing step and the drying step. 15C shows the shape of the conductive bump 82 after the third screen printing step and the drying step, and FIG. 15D shows the shape of the conductive bump 82 after the fourth screen printing step and the drying step. Show.

  Here, when the insulating sheet is penetrated by the conductive bump 82, a substantially conical conductive bump 82 having a height as shown in FIG. For this reason, it is necessary to repeat the screen printing process as shown in FIG. 13 a plurality of times, specifically, for example, four times. However, each time the screen printing process is performed once, a drying process of the substrate sheet 80 and a positioning process of the screen plate 92 by a CCD camera or the like are necessary, and these processes are performed until a sufficiently high conductive bump 82 is formed. Had to be repeated many times. In addition, when the number of screen printing steps as described above is reduced, the tip shape of the conductive bump 82 formed on the substrate sheet 80 becomes thin, and the substrate sheet 80 and the insulating sheet are alternately stacked. In addition, the contact area between the tip portion of the conductive bump 82 that has broken through the insulating sheet and the other substrate sheet that contacts the insulating sheet is reduced, and the insulating sheet connected via the conductive bump 82 is sandwiched. There was a problem that the resistance value between two substrate sheets became large.

  The present invention has been made in consideration of such points, and the tip portion of the conductive bump that broke through the non-conductive sheet and the other conductive bump-attached substrate sheet that contacts the non-conductive sheet are provided. A multilayer printed wiring board can be manufactured in which the contact area is large, and therefore the resistance value between the conductive bump-attached substrate sheets sandwiching the nonconductive sheet connected via the conductive bumps is small. It aims at providing the manufacturing method of a multilayer printed wiring board.

  In the present invention, the substrate sheet with conductive bumps on the surface of which a plurality of conductive bumps are formed and the nonconductive sheet are alternately superposed, and the conductive bumps penetrate the nonconductive sheet. A multilayer printed wiring board manufacturing method for manufacturing a multilayer printed wiring board in which the conductive bump-equipped board sheets on both sides of the nonconductive sheet are electrically connected by the conductive bumps. The step of preparing a flat substrate sheet and the step of forming the conductive bumps on the substrate sheet by deforming the flat plate substrate sheet at each location where the conductive bumps are to be formed. A step of forming a recess at each location to be formed, and a conductive bump on each recess on the surface of the substrate sheet on which a plurality of recesses are formed. The step of manufacturing the substrate sheet with conductive bumps, the substrate sheet with conductive bumps, and the non-conductive sheet are overlapped, and the overlapped body is sandwiched, and at this time, the conductive bumps attached A step of deforming each concave portion formed on the substrate sheet in the substrate sheet into a convex portion, and thus allowing the conductive bumps of the substrate sheet with conductive bumps to break through the non-conductive sheet; And a step of producing a multilayer printed wiring board by laminating the superposed body in which the conductive bumps break through the non-conductive sheet. is there.

  According to such a multilayer printed wiring board manufacturing method, a concave portion is formed in advance in each portion where each conductive bump is to be formed in the substrate sheet, and the conductive bump is formed in each concave portion of the substrate sheet. After that, the substrate sheet with conductive bumps and the non-conductive sheet are overlapped, and when the stacked body is sandwiched, each concave portion of the substrate sheet on which the conductive bumps are formed is formed as a convex portion. I am trying to deform. Then, the conductive bump of the substrate sheet with conductive bumps breaks through the non-conductive sheet by sandwiching the laminated body of the substrate sheet with conductive bumps and the non-conductive sheet, and the conductive bumps are non-conductive. A multilayer printed wiring board is manufactured by laminating superposed bodies that break through sheets. Here, when each concave portion of the substrate sheet on which the conductive bump is formed is deformed into a convex portion, the conductive bump formed in the concave portion further protrudes from the surface of the substrate sheet. For this reason, the area which the front-end | tip part of the conductive bump which broke through the nonelectroconductive sheet and the board | substrate sheet | seat with another electroconductive bump contact | abutted to this nonelectroconductive sheet contacts becomes large. This makes it possible to manufacture a multilayer printed wiring board in which the resistance value between the substrate sheets with conductive bumps sandwiching the nonconductive sheet connected via the conductive bumps becomes small.

  In the multilayer printed wiring board manufacturing method of the present invention, the method further comprises a step of preparing a flat plate member having a plurality of protrusions formed on the surface thereof, and a laminate of the substrate sheet with conductive bumps and the non-conductive sheet When the substrate is clamped, the substrate sheet with conductive bumps is placed on the surface of the flat plate member on which the protrusions are provided. At this time, the surface of the flat plate member on which the protrusions are provided and the conductive material The flat plate is formed by bringing the flat plate member, the conductive bump-equipped substrate sheet, and the non-conductive sheet together into pressure contact so that the surface on which the conductive bump is not formed in the substrate sheet with bump is brought into contact. Preferably, each of the concave portions formed on the substrate sheet of the conductive bump-equipped substrate sheet is deformed into a convex portion by the projections provided on the shaped member. Arbitrariness. At this time, the flat plate member is provided with projections so as to be aligned with the concave portions formed in the substrate sheet of the conductive bump-equipped substrate sheet to be placed on the flat plate member. It is even more preferable.

  According to the multilayer printed wiring board manufacturing method of the present invention, the contact area between the leading end portion of the conductive bump that has broken through the non-conductive sheet and the other conductive bump-attached substrate sheet that contacts the non-conductive sheet is large. Therefore, a multilayer printed wiring board is obtained in which the resistance value between the conductive bump-equipped board sheets sandwiching the non-conductive sheet connected via the conductive bumps becomes small.

  Embodiments of the present invention will be described below with reference to the drawings. 1 to 12 are diagrams showing an embodiment of a method for producing a multilayer printed wiring board according to the present invention.

  Among these, FIG. 1 is a side view showing a state when preparing a flat plate-like substrate sheet and a flat plate-like member having a plurality of protrusions formed on the surface in the method of manufacturing a substrate sheet with conductive bumps, FIG. 2 is a side view showing a method of pressing the combined body by bringing the flat substrate sheet and the flat member shown in FIG. 1 into contact with each other, and FIG. 3 is manufactured by the method shown in FIG. It is a side view which shows the board | substrate sheet | seat in which the several recessed part was formed in the surface. FIG. 4 is a side view showing another method of pressing the combined body by bringing the flat substrate sheet and the flat member shown in FIG. 1 into contact with each other.

5 to 8 are side views sequentially showing a series of operations for forming conductive bumps on the substrate sheet shown in FIG. 3, and FIG. 9 is a partially enlarged side view of FIG. FIG. 10 is a side view showing a substrate sheet with conductive bumps manufactured by the method shown in FIGS.
Further, FIG. 11 shows a method for manufacturing a multilayer printed wiring board, in which a substrate sheet with conductive bumps and a non-conductive sheet shown in FIG. 10 are placed on a flat plate member having a plurality of protrusions formed on the surface thereof. FIG. 12 is a side view showing a process in which the conductive bumps of the substrate sheet with conductive bumps break through the non-conductive sheet by sandwiching the flat plate member, the substrate sheet with conductive bumps and the non-conductive sheet; These are side views which show the multilayer printed wiring board manufactured by laminating | stacking the laminated body which the conductive bump formed through the process shown in FIG. 11 and pierced the nonelectroconductive sheet.

  Hereinafter, a method for manufacturing a substrate sheet with conductive bumps and a method for manufacturing a multilayer printed wiring board will be sequentially described.

[Method of manufacturing substrate sheet with conductive bumps]
First, as shown in FIG. 1, a substrate sheet 10 made of a conductive metal sheet such as a flat copper foil and a flat member 20 on which a plurality of protrusions 22 are formed are prepared. Here, the flat plate member 20 is composed of a metal sheet such as copper, stainless steel, or aluminum, a film such as PET, PP, or PE, or a resin sheet. Each protrusion 22 is made of metal, resin, or the like, and is formed by performing screen printing, photomolding, etching, electroforming, or the like, which will be described later, on the flat member 20. ing. The positions where the protrusions 22 are formed on the flat plate member 20 are made substantially the same as the positions where the conductive bumps 14 (described later) are to be formed on the substrate sheet 10. In addition, when each protrusion 22 is formed on the flat member 20 by a screen printing method (printing method similar to the screen printing method shown in FIGS. 5 to 9) described later, conductive bumps 14 (described later) are formed. This projection 22 can be easily registered with respect to the position to be formed.

  Next, the surface of the flat substrate sheet 10 (the upper surface of the substrate sheet 10 in FIG. 1) and the surface on which the plurality of protrusions 22 of the flat member 20 are formed (the lower side of the flat member 20 in FIG. 1). Surface). Then, as shown in FIG. 2, the combination of the substrate sheet 10 and the flat plate member 20 is clamped between a pair of rubber rolls (clamping rolls) 24 and 26. Specifically, the combination of the substrate sheet 10 and the flat plate member 20 is transported between a pair of rubber rolls 24 and 26 that are continuously rotated, and the combination is moved in the direction indicated by the arrow in FIG. As a result, the combination of the substrate sheet 10 and the flat plate member 20 is sandwiched from above and below. As a result, the surface of the substrate sheet 10 (the lower surface of the substrate sheet 10 in FIG. 2) is pressed by the protrusions 22 of the flat plate member 20, and the substrate sheet 10 is deformed, as shown in FIG. A plurality of recesses 12 are formed on the surface of 10. Here, since the position where each projection 22 is formed on the flat plate member 20 is substantially the same as the position where the conductive bump 14 is to be formed on the substrate sheet 10, each recess formed on the substrate sheet 10. The position 12 is substantially the same as the position where the conductive bumps 14 are to be formed on the substrate sheet 10.

  Note that the method of forming the plurality of recesses 12 by deforming the substrate sheet 10 is not limited to the method shown in FIG. 2, and various other methods can be used. For example, as shown in FIG. 4, the combination of the substrate sheet 10 and the flat plate member 20 is placed on the printing surface plate 28, and the substrate sheet 10 placed on the printing surface plate 28 by the pressure roll 29 is moved downward. By moving the printing surface plate 28 in the left-right direction in FIG. 4 so as to be pressed, a plurality of recesses 12 are formed at locations where the projections 22 of the flat plate member 20 in the substrate sheet 10 abut. In this way, the surface of the flat substrate sheet 10 and the surface of the flat member 20 on which the projections 22 are formed are brought into contact with each other to sandwich the combination, whereby the recess 12 is formed in the flat substrate sheet 10. Can be formed.

Next, as shown in FIGS. 5 to 8, screen printing is performed on the substrate sheet 10 on which the plurality of recesses 12 are formed.
A printing apparatus that performs such screen printing includes a printing platen 30 that holds the substrate sheet 10 by a suction force from a suction hole (not shown), and a plurality of through holes (plate holes) 32a having a predetermined pattern. A screen plate 32 such as a provided metal mask and a holding member 34 for holding the screen plate 32 are provided. Here, each through hole 32 a is formed in the screen plate 32 so as to correspond to a position where the conductive bump 14 is to be formed on the substrate sheet 10. The printing apparatus scans on the screen plate 32, and transfers a conductive paste 38 such as silver paste or solder paste placed on the screen plate 32 onto the substrate sheet 10 through the through holes 32a. A support member 33 that supports the squeegee 36 and a guide member 31 that guides the support member 33 to move in the horizontal direction (left-right direction in FIG. 5). The support member 33 can move the squeegee 36 downward in FIG. 5 or retract upward. Further, the printing apparatus includes a CCD camera 39 that images the surface of the substrate sheet 10 on the printing surface plate 30. A guide member 30 a is disposed below the printing surface plate 30. The printing surface plate 30 is movable in the horizontal direction (left and right direction in FIG. 5) along the guide member 30a.

  Next, a screen printing method using the above printing apparatus will be described. First, as shown in FIG. 5, the substrate sheet 10 is placed on the printing surface plate 30, and the substrate sheet 10 is held on the printing surface plate 30 by a suction force from a suction hole (not shown). At this time, by providing an alignment mark in advance on the substrate sheet 10, the alignment mark is captured by the CCD camera 39, and the position of the printing surface plate 30 is finely determined based on the alignment mark in the captured image. By adjusting, the position of each recess 12 formed in the substrate sheet 10 and the position of the through hole 32a of the screen plate 32 can be easily aligned.

  Then, as shown in FIG. 6, the printing surface plate 30 is moved in the horizontal direction (rightward in FIG. 5) along the guide member 30 a, and the printing surface plate 30 is positioned below the screen plate 32. At this time, the through holes 32 a of the screen plate 32 face the concave portions 12 of the substrate sheet 10.

  Then, as shown in FIG. 7, the squeegee 36 advances downward from the support member 33, the squeegee 36 pushes the screen plate 32 downward, and the screen plate 32 comes into contact with the surface of the substrate sheet 10 on the printing surface plate 30. . 7 and 9, the squeegee 36 is moved in the horizontal direction (left direction in FIG. 7) by moving the support member 33 along the guide member 31 in the horizontal direction (left direction in FIG. 7). At this time, the squeegee 36 keeps pushing the screen plate 32 downward. At this time, the conductive paste 38 passes through the through hole 32 a of the screen plate 32 and adheres to the recess 12 of the substrate sheet 10.

  Here, the principle of application of the conductive paste 38 via the screen plate 32 by the squeegee 36 will be described in more detail. The conductive paste 38 can be moved on the surface of the screen plate 32 by the squeegee 36. In the place where the through hole 32a is formed, the conductive paste 38 enters the through hole 32a. As shown in FIG. 9 and the like, the through holes 32a of the screen plate 32 are provided corresponding to the recesses 12 of the substrate sheet 10, so that the squeegee 36 presses the screen plate 32 toward the substrate sheet 10. A part of the conductive paste 38 that has entered the through hole 32 a adheres to the recess 12 of the substrate sheet 10.

  When the application of the conductive paste 38 by the squeegee 36 is completed as shown in FIG. 8, the squeegee 36 is retracted upward in FIG. 8 and the screen plate 32 is isolated from the substrate sheet 10.

  After the conductive paste 38 is adhered in each recess 12 of the substrate sheet 10 by a screen printing method using the squeegee 36, the substrate sheet 10 is dried. As a result, as shown in FIG. 10, the conductive paste 38 attached in each recess 12 of the substrate sheet 10 is thermally cured to form a substantially conical conductive bump 14.

[Manufacturing method of multilayer printed wiring board]
Next, the manufacturing method of a multilayer printed wiring board is demonstrated using FIG. 11 and FIG. 11, the substrate sheet 10 with the conductive bumps 14 and the non-conductive sheet (insulating sheet) 40 such as a prepreg shown in FIG. 10 are placed on the flat member 60 having a plurality of protrusions 62 formed on the surface. It is a side view showing a process of making the conductive bumps 14 break through the non-conductive sheet 40 by sandwiching the flat plate member 60, the substrate sheet 10 with the conductive bumps 14 and the non-conductive sheet 40, FIG. 12 is a side view showing a multilayer printed wiring board 50 manufactured by laminating an overlapping body formed by the process shown in FIG. 11 and in which the conductive bumps 14 break through the non-conductive sheet 40. is there.

  In the method of manufacturing a multilayer printed wiring board, first, a flat plate member 60 having a plurality of protrusions 62 formed on the surface is prepared. Here, as shown in FIG. 11, each flat member 60 is provided with each protrusion 62 so as to be aligned with each concave portion 12 in the substrate sheet 10 with the conductive bumps 14 to be placed on the flat member 60. It has been.

  More specifically, the flat plate member 60 is made of a metal sheet such as copper, stainless steel, or aluminum, a film such as PET, PP, or PE, or a resin sheet. Each projection 62 is made of metal, resin, or the like, and is subjected to screen printing, photomolding, etching, electroforming, or the like as shown in FIGS. Is formed. As described above, the positions where the projections 62 are formed on the flat plate member 60 are substantially the same as the positions where the recesses 12 are formed on the substrate sheet 10. When the projections 62 are formed by the screen printing method as shown in FIGS. 5 to 9, the projections 62 can be easily registered with respect to the positions where the recesses 12 are formed in the substrate sheet 10.

  Then, as shown in FIG. 11, the flat plate member 60 having a plurality of protrusions 62 formed on the surface, the substrate sheet 10 with the conductive bumps 14, the nonconductive sheet 40, and the buffer material 42 are overlapped. The superposed body is clamped with a very large force between a pair of rubber rollers (clamping rollers) 52 and 54. Here, when the respective members are overlapped, the surface of the flat plate member 60 provided with the projections 62 is brought into contact with the surface of the substrate sheet 10 where the conductive bumps 14 are not provided. Position alignment between each protrusion 62 in the member and each recess 12 in the substrate sheet 10 is performed.

  Further, when sandwiching the above-described superposed body, heating is performed at, for example, 100 ° C. to 150 ° C. by a heater (not shown).

  As shown in FIG. 11, when the above-described stacked body is clamped, the respective recesses 12 formed on the substrate sheet 10 are deformed into the projections 16 by the respective protrusions 62 provided on the flat plate member 60. . Specifically, the flat member 60 is provided with the protrusions 62 so as to be aligned with the concave portions 12 in the substrate sheet 10 with the conductive bumps 14 to be placed on the flat plate member 60. When the stacked body is clamped, the substrate sheet 10 is pressed upward by the projections 62 from the back surface (the lower surface in FIG. 11), and the portions pressed by the projections 62 in the substrate sheet 10 are illustrated. 11, the concave portions 12 formed in the substrate sheet 10 are deformed into convex portions 16, respectively.

  The above-described superposed body is sandwiched and heated from above and below, and each concave portion 12 formed in the substrate sheet 10 is transformed into the convex portion 16, whereby the back surface of the nonconductive sheet 40 (in FIG. 11). The lower surface) is pressed against the tip of the conductive bump 14 of the substrate sheet 10 provided therebelow, and the pressed portion of the non-conductive sheet 40 is broken. As a result, the conductive bumps 14 penetrate the non-conductive sheet 40.

  Thereafter, the flat plate member 60 and the buffer material 42 are removed from the above-described stacked body. Then, a multilayer printed wiring board 50 as shown in FIG. 12 is manufactured by stacking an overlapping body in which the conductive bumps 14 break through the non-conductive sheet 40. Here, in the multilayer printed wiring board 50 manufactured in this way, when the conductive bumps 14 penetrate the non-conductive sheet 40, the substrate sheets 10 on both sides of the non-conductive sheet 40 are electrically connected to each other. 14 to be electrically connected.

  As described above, according to the method for manufacturing the multilayer printed wiring board 50 of the present embodiment, the recesses 12 are formed in advance in the respective locations where the respective conductive bumps 14 are to be formed on the substrate sheet 10. When the conductive bumps 14 are formed in the respective recesses 12 of the substrate sheet 10, and then the substrate sheet 10 with the conductive bumps 14 and the non-conductive sheet 40 are overlapped, and the stacked body is clamped. The concave portions 12 of the substrate sheet 10 on which the conductive bumps 14 are formed are deformed into convex portions 16, respectively. Then, the conductive bump 14 of the substrate sheet 10 breaks through the non-conductive sheet 40 by sandwiching the superposed body of the substrate sheet 10 with the conductive bump 14 and the non-conductive sheet 40, and the conductive bump 14. The multi-layer printed wiring board 50 is manufactured by laminating stacked bodies that break through the non-conductive sheet 40. Here, when each recessed part 12 of the board | substrate sheet | seat 10 in which the conductive bump 14 was formed was each deform | transformed into the convex part 16, the conductive bump 14 formed in the recessed part 12 is more from the surface of the board | substrate sheet | seat 10. It comes out more. For this reason, the area where the tip portion of the conductive bump 14 that broke through the nonconductive sheet 40 and the other substrate sheet 10 that contacts the nonconductive sheet 40 is increased. As a result, a multilayer printed wiring board 50 is obtained in which the resistance value between the substrate sheets 10 sandwiching the non-conductive sheet 40 connected via the conductive bumps 14 is reduced. For this reason, in the manufacture of the multilayer printed wiring board 50, it is possible to suppress the occurrence of defective products having a high resistance value and to improve the yield rate.

It is a side view which shows a state when preparing a flat board | substrate sheet | seat and the flat member in which several protrusion was formed in the surface. It is a side view which shows the method of making the flat board | substrate sheet | seat shown in FIG. 1 and a flat plate member contact | abut, and pressing this combination body. It is a side view which shows the board | substrate sheet | seat with which the several recessed part was manufactured by the method shown in FIG. It is a side view which shows the other method which abuts the flat board | substrate sheet | seat shown in FIG. 1, and a flat member, and clamps this combination body. It is a side view which shows the flow of operation | movement which forms a conductive bump in the board | substrate sheet | seat shown in FIG. FIG. 6 is a side view showing a flow of an operation of forming conductive bumps on the substrate sheet following the state shown in FIG. 5. FIG. 7 is a side view showing a flow of operations for forming conductive bumps on the substrate sheet following the state shown in FIG. 6. FIG. 8 is a side view showing a flow of an operation of forming conductive bumps on the substrate sheet following the state shown in FIG. 7. FIG. 8 is a partially enlarged side view of FIG. 7. It is a side view which shows the board | substrate sheet | seat with an electroconductive bump manufactured by the method shown in FIG. 5 thru | or FIG. In the method for producing a multilayer printed wiring board, the substrate sheet with conductive bumps and the non-conductive sheet shown in FIG. 10 are placed on a flat plate member having a plurality of protrusions formed on the surface, and these flat plate member, conductive material It is a side view which shows the process which makes the conductive bump of a board | substrate sheet | seat with a conductive bump pierce a nonelectroconductive sheet | seat by pinching a board | substrate with a bump and a nonelectroconductive sheet | seat. It is a side view which shows the multilayer printed wiring board manufactured by laminating | stacking the laminated body which the conductive bump formed through the process shown in FIG. 11 and pierced the nonelectroconductive sheet. It is a side view which shows the conventional method of forming a conductive bump in a board | substrate sheet | seat. FIG. 14 is a partially enlarged side view of FIG. 13. (A)-(d) is a figure which shows the process in which a conductive bump is formed in a board | substrate sheet | seat by the conventional method, (a) is the conductive bump after the 1st screen printing process and a drying process. (B) shows the shape of the conductive bump after the second screen printing step and drying step, (c) shows the shape of the conductive bump after the third screen printing step and drying step, (D) shows the shape of the conductive bump after the fourth screen printing step and drying step.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Substrate sheet | seat 12 Concave part 14 Conductive bump 16 Convex part 20 Flat member 22 Protrusion 24, 26 A pair of rubber roll 28 Printing surface plate 29 Pressure roll 30 Printing surface plate 30a Guide member 31 Guide member 32 Screen plate 32a Through-hole 33 Support Member 34 Holding member 36 Squeegee 38 Conductive paste 39 CCD camera 40 Non-conductive sheet 42 Buffer material 50 Multilayer printed wiring board 52, 54 A pair of rubber rollers 60 Flat plate member 62 Projection 80 Substrate sheet 82 Conductive bump 90 Print surface plate 92 Screen plate 92a Through hole 94 Holding member 96 Squeegee 98 Conductive paste

Claims (3)

A substrate sheet with conductive bumps having a plurality of conductive bumps formed on the surface and a non-conductive sheet are alternately superposed, and the non-conductive sheet penetrates the non-conductive sheet. A multilayer printed wiring board manufacturing method for manufacturing a multilayer printed wiring board in which the conductive bumped substrate sheets on both sides of the conductive sheet are electrically connected by the conductive bumps,
A step of preparing a flat substrate sheet;
The step of forming a concave portion at each location where each conductive bump is to be formed on the substrate sheet by deforming the flat substrate sheet at each location where each conductive bump is to be formed. When,
Producing a conductive bump-equipped substrate sheet by forming conductive bumps in the concave portions on the surface of the substrate sheet on which a plurality of concave portions are formed;
The substrate sheet with conductive bumps and the non-conductive sheet are overlapped, and the overlapped body is sandwiched between the respective concave portions formed on the substrate sheet in the substrate sheet with conductive bumps. Deforming into a convex portion, and thus making the conductive bumps of the substrate sheet with conductive bumps break through the non-conductive sheet;
A step of producing a multilayer printed wiring board by laminating the superposed body such that the conductive bumps break through the non-conductive sheet;
A multilayer printed wiring board manufacturing method characterized by comprising: Further comprising a step of preparing a plate-like member having a plurality of protrusions formed on the surface,
When sandwiching the overlapped body of the substrate sheet with conductive bumps and the non-conductive sheet, the substrate sheet with conductive bumps is placed on the surface of the flat plate member on which the projections are provided. So that the surface of the flat plate member on which the projections are provided and the surface of the substrate sheet with conductive bumps on which the conductive bumps are not formed are in contact with each other. By projecting the substrate sheet and the non-conductive sheet together, the respective protrusions formed on the substrate sheet in the substrate sheet with the conductive bumps are projected by the projections provided on the flat plate member. The multilayer printed wiring board manufacturing method according to claim 1, wherein the multilayer printed wiring board is deformed.   The flat plate member is provided with projections so as to be aligned with the concave portions formed in the substrate sheet of the conductive bump-equipped substrate sheet to be placed on the flat plate member. The method for producing a multilayer printed wiring board according to claim 2.

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