JP2005150273A - Manufacturing method of laminated wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a laminated wiring board by which bumps are securely made to pass through a synthetic resin sheet and they can sufficiently be exposed irrespective of the size of an interval size between the bumps the repetition of pressurization work is eliminated and manufacturing efficiency can be improved. <P>SOLUTION: A first lamination pressurization process is performed for making tips of the bumps 3 pass through the synthetic resin sheet 5 and exposing them by laminating and pressurizing the synthetic resin sheet 5 on a conductive support 1 having a plurality of bumps 3. Air between the conductive support 1 and the synthetic resin sheet 5 is pressurized while it is compulsorily sucked and discharged. Then, a second lamination pressurization process is performed for laminating a conductor layer on the synthetic resin sheet 5 and pressurizing it so as to press the tips of the bumps 3 exposed from the synthetic resin sheet 5 on the conductor layer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a laminated wiring board in which wiring layers are connected by bumps.

  Conventionally, when manufacturing a laminated wiring board, first, a plurality of bumps are formed at predetermined positions on a conductive support, and then a synthetic resin-based sheet is laminated on the conductive support on which the bumps are formed. By pressing so that the synthetic resin sheet is in close contact with the conductive support, the bump penetrates the synthetic resin sheet, and the tip of the bump is exposed from the surface of the synthetic resin sheet on the opposite side of the conductive support. . And a conductor layer is laminated | stacked on a synthetic resin sheet | seat, it pressurizes, and the front-end | tip of the said bump exposed from the synthetic resin sheet | seat is crimped | bonded to this conductor layer. Thus, a laminated wiring board in which the conductive support and the conductive layer are connected by the bumps is formed (see, for example, Patent Document 1).

  By the way, in recent years, with the progress of downsizing technology of electronic components and mounting technology for the wiring substrate, the wiring substrate has been increased in density. For this reason, in this type of laminated wiring board, the number of bumps per unit area of the conductive support is increased, and accordingly, the distance between the bumps is extremely small.

However, if the adjacent bumps are close to each other, even if the bumps are pressed to penetrate the synthetic resin sheet, the bumps that are in contact with the synthetic resin sheet penetrate into the synthetic resin sheet. As a result, the bumps are not sufficiently exposed from the surface of the synthetic resin sheet. The present inventor has found out that when the laminated wiring board is manufactured, particularly when the distance between the bumps is 0.5 mm or less, the penetration to the synthetic resin-based sheet is frequently insufficient. Yes. For this reason, in order to reliably expose each bump having a very small interval dimension through the synthetic resin-based sheet, it is necessary to repeat the pressurizing operation a plurality of times, resulting in inconvenience that manufacturing efficiency is extremely poor.
JP-A-6-342977

  In order to eliminate such inconvenience, the present invention can reliably expose each bump through the synthetic resin sheet regardless of the size of the distance between the bumps, and does not require repeated pressing work. An object of the present invention is to provide a method for manufacturing a laminated wiring board capable of improving the manufacturing efficiency.

  In order to achieve such an object, the present invention provides a method in which a synthetic resin sheet is laminated on a conductive support having a plurality of bumps formed at predetermined positions, and the conductive support and the synthetic resin sheet are in close contact with each other. A first laminating and pressing step in which the tip of the bump penetrates and exposes the synthetic resin-based sheet by pressurization, and the synthetic resin-based sheet is pressed by laminating a conductor layer on the synthetic resin-based sheet. In the manufacturing method of the laminated wiring board, comprising: a second laminated pressure step for bonding the conductive support and the conductive layer with the bump by crimping the tip of the bump exposed from the conductive layer; The first lamination pressurizing step is characterized in that the pressurization is performed while forcibly sucking and discharging air between the conductive support and the synthetic resin-based sheet.

  In the method for manufacturing a laminated wiring board of the present invention, a synthetic resin-based sheet is laminated and pressed on the conductive support in the first lamination pressing step. At this time, in the first lamination pressurizing step, the pressurization is performed while forcibly sucking and discharging the air between the conductive support and the synthetic resin-based sheet. It is pulled in the penetrating direction, and the tip of the bump can be surely penetrated through the synthetic resin sheet. Thereby, a bump can be reliably exposed from the surface of a synthetic resin system sheet | seat, without repeating a pressurization operation | work several times like the past.

  At this time, the bumps are provided in close proximity such that the distance between the bumps is 0.5 mm or less, and the bumps are laminated so as to support the synthetic resin sheets. Since the air between the conductive support and the synthetic resin sheet is forcibly sucked and discharged, the pressure is applied while pulling the synthetic resin sheet between the bumps. It is possible to penetrate the synthetic resin sheet.

  Next, in the second laminating and pressing step, a conductor layer is laminated and pressed on the synthetic resin sheet from which the tip of the bump is exposed. Since the bump is reliably exposed from the surface of the synthetic resin-based sheet by the first laminating and pressing step, the tip of the bump is reliably attached to the conductor layer by the pressurizing in the second laminating and pressing step. The conductive support and the conductive layer can be favorably connected to each other by bumps.

  Examples of the conductive support include a core substrate in which a wiring pattern made of copper foil or the like is provided on a rigid surface in which a glass cloth is impregnated with an epoxy resin or the like. The synthetic resin-based sheet is an insulator, and a prepreg-based sheet formed by combining a thermoplastic resin film or a thermosetting resin film held in an uncured state with a glass cloth, an organic synthetic fiber cloth, or the like is used. be able to. In the prepreg-based sheet, in order to facilitate the penetration of the bumps, it is desirable to set the pitch of the glass cloth or the cloth of the organic synthetic fiber cloth to be larger than the diameter of the bumps. Examples of the thermoplastic resin used in the prepreg sheet include polycarbonate resin, polysulfone resin, thermoplastic polyimide resin, tetrafluoropolyethylene resin, hexafluoropolypropylene resin, polyetheretherketone resin, polyphenylene ether, polyphenylene oxide, and the like. Can be mentioned. In addition, as the thermosetting resin held in the state before curing, epoxy resin, bismaleimide triazine resin, polyimide resin, phenol resin, polyester melamine resin, fluorine resin, polyester resin, polysulfone resin, aromatic polyester series A liquid crystal polymer, cyanate resin, etc. can be mentioned.

  Moreover, in the 1st lamination pressurization process of this invention, it is preferable to pressurize the said synthetic resin type | system | group to the said electroconductive support body by the elastically deformable press member. According to this, the pressing member is elastically deformed by being pressed against the synthetic resin-based sheet, and can be pressed in a state of being in close contact with the surface of the synthetic resin-based sheet. No extra space is created between the conductive support and the synthetic resin-based sheet, and the air can be reliably exhausted when the air is sucked in the first lamination pressurizing step. . Examples of the material for forming the pressing member include natural rubber, urethane rubber, silicone rubber, fluorine rubber, and nitrile rubber.

  Moreover, in the 1st lamination | stacking pressurization process of this invention, it is preferable to pressurize in the state which pinched | interposed the laminated electroconductive support body and the synthetic resin-type sheet | seat between a pair of flexible synthetic resin release films. As the release film, a material that is flexible and does not adhere to the synthetic resin sheet is selectively adopted. For example, fluororesin, polyvinyl chloride, polyvinylidene chloride, silicone resin, polypropylene And polyvinyl alcohol.

  By providing a release film, after pressurizing the conductive support and the synthetic resin-based sheet, it is attached to the other part of the conductive support or the synthetic resin-based sheet (for example, a pressing member used during pressurization). Can be prevented.

  At this time, when the release film has flexibility, for example, when the conductive support and the synthetic resin sheet are pressed using an elastically deformable pressing member, the surface shape of the deformed pressing member The release film can be deformed along. In addition, when air is sucked in the first lamination pressurizing step, the release film is flexibly deformed along the flow of air discharged from between the conductive support and the synthetic resin sheet, and the air flow path. Can be ensured, and the air between the conductive support and the synthetic resin sheet can be smoothly discharged.

  An embodiment of the present invention will be described with reference to the drawings. 1 is an explanatory cross-sectional view showing a conductive support, FIG. 2 is a cross-sectional explanatory view of a pressurizing apparatus employed in this embodiment, FIG. 3 is an explanatory view of a pressurizing process by the pressurizing apparatus, and FIG. FIG. 5 is an explanatory sectional view showing a part of the laminated substrate, and FIG. 5 is an explanatory sectional view showing a part of the laminated substrate.

  In the manufacturing method of the present embodiment, first, as shown in FIG. 1, the core substrate 1 is used as a conductive support, and a plurality of bumps 3 are formed at predetermined positions of the wiring pattern by the copper foil 2 on the surface of the core substrate 1. The bump 3 is formed by screen-printing a conductive paste such as a silver paste or a copper paste through a metal mask having a through hole at a predetermined position laminated on the copper foil 2 and then drying. The silver paste or copper paste is prepared by mixing silver or copper powder and a binder component. The bump 3 may be formed by etching a conductor portion on the surface of the core substrate 1.

  The core substrate 1 is composed of a rigid 4 in which an epoxy resin or the like is impregnated into a glass cloth, and a copper foil 2 that forms a wiring pattern on the surface thereof, and has a thickness of 0.03 to 1.6 mm. Each bump 3 has a diameter of 100 to 300 μm and a height of 100 to 300 μm. Each bump 3 is provided in accordance with the wiring pattern. In this embodiment, some bumps 3 are provided relatively close to each other, and the distance between them is 0.5 mm or less. There is also.

  Next, as shown in FIG. 2, a prepreg-based sheet 5 having a thickness of 30 to 150 μm in which a glass cloth is combined with an epoxy resin is laminated on the upper surface of the core substrate 1 on which the bumps 3 are formed. (Vacuum laminator) At this time, a pair of release films 7 are arranged on the upper surface side of the prepreg-based sheet 5 and the lower surface side of the core substrate 1, and the prepreg-based sheet 5 and the core substrate 1 are sandwiched between both release films 7.

  As shown in FIG. 2, the pressurizing device 6 includes an upper plate 8 that can be raised and lowered, and a storage chamber 9 that is airtightly closed by the upper plate 8. The upper plate 8 is connected to pressing means (not shown) and is lowered by driving the pressing means. An air discharge port 11 is formed in the side wall 10 of the storage chamber 9. A suction means (not shown) is connected to the air discharge port 11 so that the air in the storage chamber 9 is discharged by driving the suction means. A pair of rubber pressing members 13 facing each other are provided on the upper plate 8 and the bottom 12 of the storage chamber 9.

  Subsequently, as shown in FIG. 3, the upper plate 8 of the pressurizing device 6 is lowered to pressurize the prepreg-based sheet 5 and the core substrate 1 whose upper and lower sides are covered by the two release films 7 (first lamination). Pressure step). By this pressurization, the prepreg-based sheet 5 is pressed against the core substrate 1. At this time, the pair of pressing members 13 are elastically deformed by being made of rubber, and are brought into close contact with and pressed against the prepreg sheet 5 and the core substrate 1. In addition, you may heat simultaneously in the case of the pressurization at this time.

  On the other hand, the suction means operates in conjunction with the lowering of the upper plate 8, and the air in the storage chamber 9 is sucked and discharged from the air discharge port 11. Accordingly, as shown in FIG. 4, the air between the prepreg sheet 5 and the core substrate 1 is forcibly discharged. Also, when air flows out between the prepreg-based sheet 5 and the core substrate 1, it passes through the ends of both release films 7, but both release films 7 have flexibility, Since the air flows so as to open the air flow path, the air flows out smoothly. Thus, the prepreg-based sheet 5 and the core substrate 1 are pressurized by the pair of pressing members 13 and at the same time, the air between the prepreg-based sheet 5 and the core substrate 1 is forcibly discharged, whereby the prepreg system The sheet 5 is pulled downward, and the bump 3 smoothly penetrates the prepreg sheet 5.

  Thereafter, the upper plate 8 of the pressure device 6 rises and the pair of pressing members 13 are separated. At this time, by providing the release film 7, sticking between the pressing member 13 and the prepreg sheet 5 can be prevented.

  When the prepreg sheet 5 and the core substrate 1 are laminated in this manner, the bumps 3 penetrate the prepreg sheet 5, so that the tips of the bumps 3 are reliably exposed from the upper surface of the prepreg sheet 5.

  Then, as shown in FIG. 5, the core substrate 1 on which the prepreg sheet 5 is laminated is laminated on another printed wiring board 14 (conductor layer) on the surface where the bumps 3 are exposed. Although not shown in the figure, it is mounted on a multi-layer press while being sandwiched between metal jigs, and is heated and pressed in a vacuum (second laminating and pressing step). As a result, the tips of the bumps 3 exposed from the prepreg-based sheet 5 are pressed against the wiring pattern 15 of the printed wiring board 14, and the copper foil 2 of the core substrate 1 and the wiring pattern 15 are connected by the bumps 3.

Explanatory sectional drawing which shows the electroconductive support body in embodiment of this invention. Cross-sectional explanatory drawing of the pressurization apparatus employ | adopted in this embodiment. Explanatory drawing of the pressurization process by a pressurization apparatus. Explanatory sectional drawing which shows a part of pressurization process. Explanatory sectional drawing which shows a part of laminated substrate in this embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Core board | substrate (electroconductive support body), 3 ... Bump, 5 ... Pre-preg system sheet | seat (synthetic resin system sheet), 7 ... Release film, 13 ... Pressing member, 14 ... Other printed wiring boards (conductor layer) .

Claims (4)

A synthetic resin sheet is laminated on a conductive support having a plurality of bumps formed at predetermined positions, and the bump is applied to the synthetic resin sheet by pressurizing the conductive support and the synthetic resin sheet in close contact with each other. A first lamination pressurizing step for penetrating and exposing the tip of
The conductive resin layer is laminated on the synthetic resin sheet and pressed to press the bump tip exposed from the synthetic resin sheet to the conductive layer, and the conductive support and the conductive layer are bonded by the bump. In a method for manufacturing a laminated wiring board comprising: a second laminated pressurizing step for connecting
In the first laminated pressurizing step, the pressurization is performed while forcibly sucking and discharging air between the conductive support and the synthetic resin-based sheet.   2. The production of a laminated wiring board according to claim 1, wherein in the first laminating and pressing step, the synthetic resin sheet is pressed against the conductive support by an elastically deformable pressing member. Method.   In the first laminating and pressing step, the laminated conductive support and the synthetic resin-based sheet are pressed while being sandwiched between a pair of flexible synthetic resin release films. 3. A method for producing a laminated wiring board according to 2.   The method for manufacturing a multilayer wiring board according to any one of claims 1 to 3, wherein an interval between at least the pair of bumps is 0.5 mm or less.

Images