JP4485587B2 - Printed wiring board manufacturing apparatus and printed wiring board manufacturing method - Google Patents

Description

  The present invention relates to an apparatus and a method for manufacturing a multilayer printed wiring board in which a conductive foil on which conductive bumps are formed and an insulating resin layer are laminated.

  With the miniaturization and high functionality of various electronic devices, the demand for high-density mounting of electronic components is increasing. Correspondingly, multilayer printed wiring boards having a structure in which insulator layers and wiring layers are alternately laminated are widely used as printed wiring boards. Multilayer printed wiring boards are designed to meet the demand for higher density and higher functionality by making the wiring layers multi-layered. Interlayer connections between wiring layers are made using through holes, etc. Yes.

  A multilayer printed wiring board in which such interlayer connection of wiring layers is performed by via holes has a problem that it is difficult to cope with high-density mounting.

  For example, since it is impossible to form a wiring or mount an electronic component in a region provided with a through hole, improvement in wiring density and mounting density is restricted. Further, in recent years, the wiring of a printed wiring board has been increased in density with the high-density mounting of electronic components. In order to cope with such miniaturization of wiring, if it is attempted to reduce the diameter of the through hole, there is a problem that it is difficult to ensure the reliability of interlayer connection.

  In addition, the formation of the connection between the wiring layers by the through hole is redundant because it involves a through hole forming process and a plating process, and there is a problem from the viewpoint of productivity. For example, in the process of forming a through hole, a hole is drilled one by one, so that a lot of time is required for the drilling operation. In particular, in this step, the productivity is extremely lowered when the hole diameter of the through hole is reduced. Furthermore, after making the through hole, a polishing process and a plating process for deburring are required. Moreover, high accuracy is required for the formation position of the through hole, and it is necessary to take into consideration the plating adhesion on the inner wall surface of the through hole. For this reason, the precision of through-hole formation, management of formation conditions, etc. are also complicated. Furthermore, a conventional multilayer printed wiring board that performs interlayer connection using through-holes requires a through-hole formation step. In particular, when the diameter of the through hole is about 0.2 mm or less, there is a problem that the time required for forming the through hole is increased and the productivity is remarkably lowered. Such a problem can be solved in a multilayer wiring board in which interlayer connection is performed by conductive bumps.

  In addition, in the plating process for forming electrical connections between a plurality of wiring layers through through holes, process management such as chemical liquid concentration management and temperature management is complicated. Furthermore, the equipment for forming the through holes and the equipment necessary for plating become large.

  Such interlayer connection of multilayer printed wiring boards by through holes reduces the productivity of printed wiring boards (PWB), and it is difficult to meet the demand for cost reduction.

  In order to simplify the electrical connection between the wiring layers of the multilayer printed wiring board, a method of connecting the wiring layers with conductive bumps has also been proposed. In this method, conductive bumps are formed on via lands or the like, which are interlayer connection portions formed in a wiring circuit, and the conductive bumps are inserted in the thickness direction of an interlayer insulating layer such as a prepreg, thereby opposing wirings. It establishes connection with via land formed in the layer.

  The wiring circuit interlayer connection employing such conductive bumps has advantages such as a simple configuration, a small number of processes and high productivity, and compatibility with high-density mounting. However, the problems described below are recognized in the printed wiring board in which the conductive bumps are used to make the interlayer connection of the wiring circuit.

  The conductive bump is formed on a conductive foil such as a copper foil by printing a plurality of times using, for example, a mask or the like, but there has been no apparatus capable of automatically performing this process. In manual printing, it is difficult to keep a plurality of printing intervals constant, which causes a problem that the quality of the conductive bumps becomes uneven. Further, although the aspect ratio of the conductive bump formed varies depending on the number of times of printing, there is a problem that managing a very large number of times of printing on the conductive foil is a heavy burden.

  FIG. 19 is a diagram schematically showing a manufacturing process of a multilayer printed wiring board using a conventional conductive bump, and shows a process of penetrating an insulating resin layer by a conductive bump formed on a conductive foil. .

  Here, a conductive foil 52 such as a copper foil formed with a conductive bump 51 having a substantially conical shape and an insulating resin layer 53 such as a semi-cured prepreg are laminated, and heated and pressed by a flat press. Thus, the conductive bump 51 is penetrated through the insulating resin layer 53. 91a and 91b are press plates of a flat press machine. Here, in order to maintain the shape of the conductive bumps 51, the release sheet 56 is stacked on the insulating resin layer 53 and pressed.

  However, it is difficult to press uniformly over the entire laminate with such a flat press, and all of the conductive bumps 51 formed on the conductive foil 52 due to non-uniform pressure are in good condition. There is a problem that the insulating resin layer 53 cannot be penetrated. Since the conductive bump 51 is involved in the interlayer connection of the wiring layers of the multilayer printed wiring board, such a penetration defect is directly connected to the defect of the multilayer wiring board.

  Further, in the step of penetrating the conductive bump 51 by this flat press, the conductive foil 52, the insulating resin layer 53, and the release sheet 56 must be laminated for each press, and after the press, There is a problem that productivity is low, for example, when the pressing is performed manually, especially when the pressing is performed manually.

  The multilayer printed wiring board in which the interlayer connection is formed by the conductive bump has a problem that it is difficult to put into practical use due to such problems.

  Further, when the conductive foil 52 and the insulating resin layer 53 are laminated, there is a problem that the conductive foil is easily contaminated by the powder of the resin constituting the insulating resin layer.

  A conventional printed wiring board manufacturing apparatus in which the conductive foil 51 and the insulating resin layer 53 are laminated has a structure as shown in FIG. For example, an insulating resin layer 53 such as a prepreg set at another predetermined position is adsorbed and transferred to a conductive foil 52 such as a Cu foil set at a predetermined position by a conductive head. Overlay on the foil 52.

  However, the conventional apparatus has the following problems. First, since the conventional suction head partially holds the insulating resin layer in a dot-like region, wrinkles or the like are generated when the insulating resin layer is held, thereby forming the insulating resin layer. There is a problem that the resin is scattered as powder. When the scattered insulating resin powder such as prepreg adheres to the surface of the conductive foil or the like, there is a problem in that etching defects occur due to unevenness due to resin adhesion after pressing or cause dents.

  Further, the prepreg powder generated in the prepreg cutting process or the like adheres to the surface or end surface of the prepreg, and there is a problem that this powder is scattered to cause the same problem as described above.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus and a method for producing a multilayer printed wiring board having no through defects and high productivity. Another object of the present invention is to provide a multilayer printed wiring board manufacturing apparatus and method that can uniformly pressurize a laminate including conductive bumps and an insulating resin layer.

A printed wiring board manufacturing apparatus according to an aspect of the present invention has the following configuration. That is, a printed wiring in which a conductive foil having a substantially conical conductive bump formed on the first surface and a semi-cured insulating resin sheet are stacked, and the insulating resin sheet is penetrated by the conductive bump. An apparatus for manufacturing a plate, comprising: a first roller; a second roller arranged in parallel with the first roller and a rotation axis; maintaining a predetermined gap; the conductive foil; and the insulating material. A resin sheet and a release sheet, the insulating resin sheet being sandwiched between the first surface of the conductive foil and the release sheet, the first roller and the second roller Means for supplying through the gap, rotational speed of the first roller and the second roller, and the conductive foil supplied through the gap between the rollers, the insulating resin sheet And the supply speed of the release sheet are synchronized. The driving means for driving the first roller and the second roller, and the size of the gap between the first roller and the second roller so that the conductive bump penetrates the insulating resin layer. Adjusting means for adjusting the first and second rollers, the first roller and the second roller having heating means therein, and expansion and deformation of the first roller and the second roller by heating. It is characterized by a hollow structure so as not to cause nonuniformity in the gap distribution in the width direction .

By the middle empty structure to prevent uneven gap size of the two rollers due to the expansion of the roller due to thermal expansion, the conductive foil, the insulating resin layer, a laminate of the release sheet more It can be uniformly pressurized and heated.

Further, the first B over La and second B over La of the heating means may be provided uniformly to so that the temperature distribution in the width direction. For example, by adjusting the winding density of the winding coil of the infrared heater, the surface temperature distribution of the roller is suppressed to a small range. Therefore, eccentricity of the roller is prevented, and the laminate is heated and pressurized more uniformly.

Moreover, the may be further comprising means you supplied to the gap between the release sheet and the second roller and the first roller mold release sheet to be so that in the constant tension. By supplying the release sheet to the gap between the first rotating roller and the second rotating roller while adjusting the tension to be uniform, it is possible to prevent the release sheet from wrinkling during pressurization. . Therefore, the laminate is pressed with a more uniform force.

Further, as the contact area between the first roller and the conductive foil is increased, the conductive foil may be further comprising means you supplied along the first roller. By adjusting the supply angle so that the contact area between the conductive foil and the roller is increased, preliminary heating of the laminate is performed before pressing. Accordingly, the insulating resin layer is penetrated more uniformly and smoothly by the conductive bump.

A method for manufacturing a printed wiring board according to an aspect of the present invention includes: laminating a conductive foil having a substantially conical conductive bump formed on a first surface and an insulating resin sheet in a semi-cured state; A method for manufacturing a printed wiring board in which the insulating resin sheet is penetrated by a conductive bump , and includes a heating means, and does not cause unevenness in the gap distribution in the width direction due to expansion deformation due to heating. In the first roller and the second roller , which have a hollow structure and are arranged with the rotation shafts kept parallel to each other , the heating means is operated so that the first roller and the second roller In the gap, the conductive foil, the insulating resin sheet, and the release sheet are sandwiched between the first surface of the conductive foil and the release sheet. The first roller and the second roller And supplying to pass the gap between the La. The present invention forms a conductive bump by printing a conductive paste on a conductive foil, laminates an insulating resin layer on the conductive foil, and heats and presses the conductive bump to form a synthetic resin sheet. In the printed wiring board manufacturing apparatus for electrically connecting the upper and lower conductive metal foils by passing through and then heating, pressing and molding another conductive metal foil. The process of penetrating the conductive bumps into the synthetic resin sheet can be adapted to materials with different thicknesses by changing the two rolls and the conductive bump penetrating auxiliary material, and further changing the main material feeding angle, thereby improving the yield. be able to.

  According to the present invention, even when the insulating resin layer is penetrated by the conductive bump formed on the conductive foil, the pressurization is equalized compared to the conventional press using two parallel plates. Can be done. Therefore, uneven pressure is eliminated and the yield can be improved. Furthermore, the time required for setting and disassembling the laminate can be greatly reduced by the continuous processing operation, and productivity can be improved.

  Moreover, while making two rolls into a hollow structure and suppressing the temperature distribution of the heating of the roll by the heating means, the eccentricity of the roll due to the thermal expansion can be suppressed, and the uniform distribution of pressure while heating can be ensured. It became so.

  Hereinafter, each embodiment of the present invention will be described in detail.

  First, FIG. 1 is a diagram schematically showing a configuration of an apparatus for manufacturing a printed wiring board in a state before being provided to a manufacturing apparatus according to the present invention.

  The printed wiring board manufacturing apparatus includes a circulating means 11 that circulates a conductive foil along a predetermined path, and is disposed in the path of the circulating means 11, and a conductive paste is applied to the conductive foil. When the number of times the conductive paste is printed on the conductive foil reaches a preset number, the printing means 12 for printing, and the conductive foil is disposed in the path of the circulation means 11. Discharge means 13 for discharging from the circulation means 11 is provided.

  Examples of the printing unit 12 include a screen printer. That is, the conductive paste may be printed using the supplied conductive foil or a mask in which pits or the like are formed at predetermined positions of the conductive foil on which the conductive paste has already been printed by the printing means 12. Good. As the circulation means 11, for example, a conveyor that conveys the conductive foil discharged from the printing means, a direction changing machine that changes the direction of conveyance, an automatic feeder that throws the conductive foil into the printing means, and the like are used in appropriate combination. You can do it. At this time, if an automatic feeding device and an automatic discharging device are provided as a part of the circulation means 11, the conductive paste is automatically printed on the conductive foil circulating through the path of the circulation means 11. Can do. The conductive foil on which the conductive paste is printed is circulated and supplied to the same one printing means 12 by the circulation means 11.

  On the other hand, when the number of times the conductive paste is printed on the conductive foil reaches a preset number, the conductive foil is discharged from the circulation means 11 by the discharge means 13. As this discharging means, for example, a memory in which the number of times of printing is set and a counter for counting the number of times of printing may be combined. For example, by comparing the count value of the counter with the set value stored in memory, the conductive foil on which the conductive paste is printed is circulated through the circulation path, and the conductive paste is further printed. It is possible to determine whether or not to discharge. In addition, a value fixed by the apparatus may be used as the set value of the number of times of printing, or an operator may be provided with an input unit.

  2 is a diagram schematically showing an example of a processing flow of the control system of the printed wiring board manufacturing apparatus shown in FIG. 1, and FIG. 3 is a configuration of the control system of the printed wiring board manufacturing apparatus shown in FIG. FIG. Each time the conductive paste is printed once by the printing means, the number of times of printing C is counted and compared with a preset set value S. If the count value C of the number of times of printing is less than the set value S, the conductive foil is recirculated and repeatedly introduced into the printing means. If the count value C of the number of times of printing becomes equal to the set value S, the conductive foil is discharged from the circulation means and no conductive paste is printed. The discharged conductive foil is introduced into a drying furnace, for example.

  FIG. 4 is a diagram schematically showing a state where the conductive paste is printed on the conductive foil by the printing means.

  The conductive bumps 14 can be formed by screen-printing a conductive paste 18 on the conductive foil 17 using a metal mask 16 having pits 15 formed at positions where the conductive bumps 14 are formed. . After the conductive paste 18 is swept with the squeegee 19 and the pits 15 are filled with the conductive paste 18, the metal mask 16 is pulled up to form the substantially conical conductive bumps 14 on the conductive foil 17 ( FIG. 4 (a) and FIG. 4 (b)). In order to increase the aspect ratio of the conductive bump 14, that is, the ratio of the diameter and height of the bottom surface of the conductive bump 14, the conductive paste 18 is printed a plurality of times, and the conductive paste 18 is further conductive on the printed conductive paste 18. What is necessary is just to print a paste.

  FIG. 5 is a diagram schematically showing a state of conductive bumps formed when the conductive paste 18 is printed a plurality of times on the conductive foil 17. FIG. 5A shows the state of the conductive bump formed when the conductive paste is printed once, FIG. 5B shows the state when printed twice, and FIG. 5C shows the state of the conductive bump formed when printed three times. Show.

  At this time, it is preferable to use the same mask for printing the conductive paste a plurality of times in order to prevent positional displacement and to uniformly form all the conductive bumps. Alternatively, the printed conductive paste may be preliminarily dried and then further printed.

  This printed wiring board manufacturing apparatus employs a configuration in which the conductive foil is circulated to the same printing means by the circulation means and printing is performed a plurality of times, so that the conductive paste is printed with the same mask. Can do. For this reason, the shift | offset | difference of a printing position can be suppressed to the minimum and many conductive bumps can be formed uniformly on conductive foil.

  As described above, the printed wiring board manufacturing apparatus prints the conductive paste on the conductive foil a plurality of times using the same mask to form conductive bumps, and the conductive foil discharged from the printing means. Is provided with circulation means for re-feeding the same to the same printing means. In the predetermined path of the circulation means including the printing means, not only the printing means but also a drying means such as a drying furnace for preliminarily drying the printed conductive paste may be provided.

  FIG. 6 is a diagram showing an example of the configuration of a printed wiring board manufacturing apparatus provided with a drying means on the circulation path of the circulation means. In this apparatus, printing means 12, discharge means 13, and drying means 20 for preliminarily drying the conductive paste are provided on the circulation path of the circulation means 11, and the number of times the conductive paste is printed becomes a set value. Printing and drying are repeated until the end. In the configuration illustrated in FIG. 6, since the discharge unit 13 is disposed on the downstream side of the printing unit and the upstream side of the drying unit, the conductive foil that has finished the last printing does not pass through the drying unit 20 and circulates. Discharged from. The discharged conductive foil is introduced into a main drying furnace, for example, and dried more strongly than the preliminary drying.

  In this way, the conductive paste printed on the conductive foil is dried by a preliminary drying means, and this is repeated a predetermined number of times to increase the aspect ratio (ratio of the diameter and height of the bottom surface of the conductive bump). Conductive bumps can be formed. At this time, in this printed wiring board manufacturing apparatus, factors affecting the quality of the conductive bumps, such as the number of times of printing, the time of preliminary drying, and the transport time, can be managed under predetermined conditions. Therefore, a printed wiring board with uniform characteristics and high reliability can be manufactured. In addition, the quality of the conductive bumps can be made uniform by keeping the interval between the steps constant.

  Further, in this printed wiring board manufacturing apparatus, for example, a method of arranging a plurality of printing means and printing a conductive paste on the conductive foil by these printing means is not adopted, and the same printing means is not subjected to the conductive printing. By circulating the conductive foil, not only can the cost of the apparatus be reduced, but multiple printings can be performed using the same mask. By performing printing a plurality of times necessary for forming the conductive bump using the same mask, it is possible to form a high-quality conductive bump with little misalignment. Therefore, the reliability of the interlayer connection of the multilayer printed wiring board can be improved.

  Next, FIG. 7 is a diagram schematically showing a configuration of another apparatus for manufacturing a printed wiring board in a state before being provided to the manufacturing apparatus according to the present invention.

  This printed wiring board manufacturing apparatus has two circulation means 11a and 11b which are symmetrically arranged in parallel, and each of the circulation means 11a and 11b is provided with one printing means 12a and 12b. It is what.

  In this example shown in FIG. 7, the drying means (drying furnace) 20 is shared by the two circulation means 11a and 11b. Since the tact time required for pre-drying is relatively short, productivity is improved by sharing.

  FIG. 8 is a diagram schematically showing an example of a more specific configuration of the printed wiring board manufacturing apparatus shown in FIG. The conductive foil such as copper foil is first distributed to the first circulation system 11a and the second circulation system 11b by the sorting type charging direction changer 31.

  The distributed conductive foil is conveyed by the stock conveyors 32a and 32b and introduced into the conductive foil feeders 33a and 33b.

  The conductive foil feeding machines 33a and 33b feed the conductive foil into the printing machines 12a and 12b. The printers 12a and 12b print a conductive paste on a predetermined position on the input conductive foil by screen printing using the metal mask as described above.

  The conductive foil discharged from the printers 12a and 12b is transported by the discharge transporters 34a and 34b, the transport direction is changed by the direction changers 35a and 35b, and is introduced into the discharge means 13 by the conveyors 36a and 36b. For example, a sorting direction changer may be used as the discharging means.

  As described above, the discharging means 13 compares the number of times of printing, that is, the number of times the conductive foil has circulated around the first circulation system 11a and the second circulation system 11b with the preset number of times of printing. It is determined whether the conductive foil remains in the circulation system or is discharged from the circulation system.

  The number of times of printing may be counted by, for example, providing a counter in the printing machines 12a and 12b, or by providing a counter in the conveyance path, for example. Further, how many times the conductive paste is printed on one conductive foil may be set in advance, or a means for inputting a set value of the number of times of printing may be provided. The number of times the conductive paste is printed on the conductive foil to form conductive bumps depends on the properties of the conductive paste, physical properties such as thixotropy, process conditions such as process temperature, and the shape of the conductive bumps to be formed. It may be determined as follows.

  Now, it is assumed that 20 conductive foils are loaded into the sorting type loading direction changer 31 at a time. Further, it is assumed that the conductive paste is printed three times. The sorting type throwing direction changer 31 distributes the supplied 20 conductive foils into 10 sheets each and introduces them into the first circulation system 11a and the second circulation system 11b. The 10 conductive foils after the first printing are introduced into the drying furnace 20 without being discharged by the discharging means, and are dried at a temperature of about 80 to 150 ° C. for about 30 seconds. At this time, the heating condition may be adjusted according to the temperature of the drying furnace 20 and the time of passing through the drying furnace 20. As described above, in the printed wiring board manufacturing apparatus of the present invention, since the tact time of the printed conductive paste is relatively short, the drying furnace 20 is configured to be shared by the two circulation systems 11a and 11b. Adopted. Therefore, not only can the installation area of the drying furnace be reduced and the cost required for installation can be reduced, but also the ratio of the volume and surface area of the drying furnace can be reduced, and stable heating can be performed efficiently. The conductive foil that has finished the third printing is discharged from the circulation path by the discharging means. In this configuration, the discharged conductive foil is introduced into the main drying furnace and dried at a temperature higher than that of the preheating furnace.

  The printed wiring board manufacturing apparatus shown in FIGS. 7 and 8 includes a plurality of circulation systems. For this reason, the throughput is improved. In addition, in a double-sided copper-clad board or the like, a single insulating resin layer (prepreg) is formed by being sandwiched between two conductive foils on which conductive bumps are formed. According to this printed wiring board manufacturing apparatus, A plurality of conductive foils sandwiching such a single insulating resin layer can be manufactured at the same time. Thus, a printed wiring board in which interlayer connections are formed by conductive bumps suitable for high-density mounting can be easily and stably manufactured. Moreover, it can carry out, keeping each printing process, a preliminary drying process, and the time required for conveyance constant. Therefore, a large number of conductive bumps formed on a single conductive foil can be formed uniformly. Therefore, a highly reliable printed wiring board can be formed.

( Basic Reference Example ) FIG. 9 is a perspective view schematically showing an example of the configuration of a printed wiring board manufacturing apparatus according to a basic reference example , and FIG. 10 is a schematic view of the printed wiring board manufacturing apparatus shown in FIG. FIG. 10 is a lateral view (FIG. 10A) and a top view (FIG. 10B). This printed wiring board manufacturing apparatus laminates and passes a conductive foil in which conductive bumps are formed in a gap between two rolls and an insulating resin layer such as a prepreg. The conductive bumps are passed through the insulating resin layer. Is to penetrate. That is, this printed wiring board manufacturing apparatus laminates a conductive foil 52 having a substantially conical conductive bump 51 formed on a first surface and a semi-cured insulating resin layer 53 to form a conductive bump. 51 is a printed wiring board manufacturing apparatus that penetrates an insulating resin layer 53 by a first roll 54, and a first roll 54, and a first roll 54 that is disposed in parallel with the first roll 54 and a rotation axis while maintaining a predetermined gap. 2 roll 55, conductive foil 52, insulating resin layer 53, and release sheet 56, and surface of the insulating resin layer 53 on which conductive bumps 51 of conductive foil 52 are formed and the release sheet. 56, a means for supplying the first roll 54 and the second roll 55 so as to pass through the gap between the first roll 54 and the second roll 55, the rotational speeds of the first roll 54 and the second roll 55, and these Conductive foil supplied to pass through the gap between rolls 2. Driving means for driving the first roll 54 and the second roll so that the supply speeds of the insulating resin layer 53 and the release sheet 56 are synchronized, and the conductive bumps 51 connect the insulating resin layer 53 to each other. Adjusting means for adjusting the size of the gap between the first roll 54 and the second roll 55 so as to penetrate is provided. Moreover, the 1st roll 54 and the 2nd roll 55 are equipped with heating means, such as an electric heater, for example, and heat a laminated body so that penetration of the insulating resin layer by an electroconductive bump becomes easy. Reference numeral 63 denotes a transport roll that transports the conductive foil 52 and the insulating resin layer 53. The release sheet 56 is used to hold the penetrating conductive bumps 51 so as not to be crushed. The release sheet 56 is supplied from a release sheet supply roll 57, and after passing through the gap between the first roll 54 and the second roll 55, from the laminate of the conductive foil and the insulating resin layer. It is peeled off and taken up by a release sheet take-up roll 58. A release sheet 56 is always supplied to the gap between the two rolls 54 and 55. The release sheet 56 is supplied to the gap between the first roll 54 and the second roll 55 with the supply angle adjusted by the guide roll 59. The guide roll 59 may be variable and may be adjusted so that the tension of the release sheet supplied to the gap between the first roll 54 and the second roll 55 is constant. The guide roll 60 gives a predetermined tension necessary for peeling the release sheet 56 from the laminate of the conductive foil 52 and the insulating resin layer 53.

The first roll 54 and the second roll 55 are laminated bodies of the conductive foil 52, the insulating resin layer 53, and the release sheet 56 that hold the rotation axes in parallel and are supplied to the gaps between these rolls. It is driven to rotate in synchronism with the supply speed. Here, driving to rotate synchronously means that the stacked body passes through the gap between the first roll 54 and the second roll 55, and the first roll 54 and the second roll 55 that rotate. And driving so that the tangential speed of the surface is substantially equal. The laminated body of the conductive foil 52 formed with the conductive bumps 51, the insulating resin layer 53, and the release sheet 56, introduced into the gap between the first roll 54 and the second roll 55, The conductive bump 51 penetrates the insulating resin layer 53 by being pressed and heated by the pair of rolls. The magnitude of the applied pressure may be adjusted according to the size of the gap between the two rolls. Since the apparatus for manufacturing a multilayer printed wiring board of this is pressurized by laminating a release sheet 56, conductive bumps 51 penetrating the insulating resin layer 53 may be maintained without damaging its shape.

  As described above, in the conventional flat pressing method, an insulating resin layer and a release sheet as an auxiliary material for penetration are pressed on a conductive foil on which conductive bumps are formed as shown in FIG. Set and press on a flat plate. However, it is difficult to press so that the pressure is uniformly applied to all the parts, and the pressing unevenness is generated as shown in FIG. 19B, and it is difficult to penetrate all the conductive bumps.

  In this multilayer printed wiring board manufacturing apparatus, the conductive foil 52 and the insulating resin layer 53 are separated from the release sheet 56 by a linear pressure region formed in the gap between the first roll 54 and the second roll 55. Since pressurization is performed through the press, more uniform pressurization can be performed as compared with a conventional flat press. Therefore, a large number of conductive bumps 51 can penetrate the insulating resin layer in a uniform state. Moreover, since it is the structure which can perform the press of a several laminated body continuously, productivity of the penetration process of the insulating resin layer 53 by the conductive bump 51 can be improved significantly. Moreover, since the release sheet 56 used as the auxiliary material for penetration can also be automatically peeled off, reliable bump penetration and lead time can be significantly shortened, and productivity can be greatly improved.

(Embodiment) FIG. 11 in the manufacturing apparatus of printed wiring board according to implementation embodiments of the present invention, showing the structure of a pair of rolls performing the pressurization of the laminate schematically.

  The first roll 54 and the second roll 55 perform heating simultaneously with pressurization of the laminate. The laminated body is heated at such a temperature that the insulating resin layer of about 100 to 160 ° C. is softened but not hardened. When the structure of the roll is clogged (FIG. 11 (a)), the central portion of the roll expands greatly by heating with a heater or the like, resulting in eccentricity. Since a narrow portion and a wide portion are formed in the gap between the first roll 54 and the second roll 55, the portions at both ends of the laminated body of the laminated body are not sufficiently pressurized, and problems frequently occur in the penetrating state. . Therefore, in order to prevent eccentricity even if heated, it is preferable to employ a roll having a hollow structure as the first roll and the second roll in this printed wiring board manufacturing apparatus.

  FIG. 11B schematically shows the structure of the first roll 54 and the second roll 55 having such a hollow structure. In this example, the laminate of the conductive foil 52, the insulating resin layer 53, and the release sheet 56 formed by the first roll 54 and the second roll 55 can be uniformly and accurately pressurized and heated. As described above, the inside of the roll is hollow. The roll is made of iron, stainless steel, etc. The width of the roll is about 400 to 500 mm, and the diameter is about 80 to 100 mm. The wall thickness d of the roll is about 10 mm, and the diameter of the rotating shaft is about 30 mm. The gap between the first roll and the second roll can be adjusted by an adjusting means 61 formed integrally with a driving means for rotationally driving the roll. For this reason, the first roll 54 and the second roll 55 are uniformly expanded and contracted as a whole, so that the size of the gap can be kept uniform over the entire roll. For this reason, 100% of the conductive bumps could be penetrated only by finely adjusting the size of the gap between the first roll 54 and the second roll 55.

  Further, in this printed wiring board manufacturing apparatus, an infrared heater is provided inside the roll as a heating means for heating the first roll 54 and the second roll 55. The winding density of the coil 62 constituting the infrared heater is adjusted to be small at the center and large at the end so that the difference between the temperature Tc at the center of the roll and the temperature Te at the end becomes small. Arranged.

  12 shows the surface temperature of the roll when the winding density of the coil 62 in the rotating roll is constant (FIG. 12A) and when it is small at the center and large at the end (FIG. 12B). It is a figure which shows the mode of distribution of. When the winding density of the coil is constant, the surface temperature Tc of the roll becomes higher than the temperature Te at the end, but the surface of the roll can be adjusted by adjusting the winding density of the coil 62. It can be seen that the temperature is uniformly distributed and Tc and Te are substantially equal.

  Thus, the eccentricity of the roll can be prevented by optimizing the arrangement of the heating means for heating the first roll 54 and the second roll. Furthermore, the surface temperatures of the first roll 54 and the second roll 55 become more uniform, and the conductive bumps can penetrate more uniformly into the insulating resin layer. Therefore, a printed wiring board with uniform characteristics and high reliability can be manufactured.

  (Reference Example 1) The present inventors have found that the tension for stretching the release sheet is very important as a condition for penetrating all the conductive bumps satisfactorily. Depending on the type of printed wiring board to be manufactured, there are various variations in the height and diameter of the conductive bumps to be provided. Therefore, it is necessary to change the thickness and material of the release sheet used according to the shape of the conductive bumps. There is. Furthermore, it is necessary to adjust the magnitude of the tension that stretches the release sheet according to the release sheet to be used. This is because if the release sheet 56 is wrinkled, it is impossible to uniformly press the conductive foil 52 and the insulating resin layer.

  FIG. 13 is a diagram schematically showing an example of the structure of a release sheet supply roll 57 provided in the printed wiring board manufacturing apparatus according to the reference example. In the printed wiring board manufacturing apparatus shown in FIG. 9, it is necessary to rotate the take-up roll 58 faster than the supply roll 57 of the release sheet 56. Further, it is necessary to buffer changes in tension due to changes in roll diameter. In the supply roll 57 illustrated in FIG. 13, the supply roll 57 can be pressurized from both the left and right sides of the rotation shaft by a spring 71 and a screw 72. The release sheet 56 can be continuously and smoothly supplied by biting a sliding plate 73 made of polyvinylidene fluoride or the like having a small friction. When a predetermined force is applied from both sides of the shaft, the supply roll rotates following the rotation of the rotating shaft, and the release sheet is supplied while maintaining a predetermined tension. Therefore, even when a large force is momentarily applied, the magnitude of the tension of the release seam 56 between the supply roll 57 and the first roll 54 and the second roll 55 can be kept constant. it can. FIG. 14 shows the tension of the release sheet stretched between the supply roll and the first and second rolls with and without the supply roll capable of adjusting the tension as illustrated in FIG. It is a graph which shows typically the fluctuation | variation of. Thus, by providing the tension adjusting means as illustrated in FIG. 13, it is possible to reduce the variation in the tension of the release sheet.

  Further, the tension of the release sheet may be adjusted by changing the position of the guide roll 59 by making the guide roll 59 variable.

  By adopting such a configuration, the release sheet 56 can be stably supplied while maintaining a predetermined tension according to the shape and size of the bumps. Therefore, the conductive bumps can be stably penetrated even for the conductive bumps having a small size and the insulating resin layers having a small thickness.

  Reference Example 2 FIG. 15 is a diagram schematically showing the configuration of a printed wiring board manufacturing apparatus according to another reference example. FIG. 16 is an enlarged view schematically showing the first roll and the second roll of the printed wiring board manufacturing apparatus shown in FIG.

  This printed wiring board manufacturing apparatus includes a first roll 54 and a second roll 55 of a laminate of a conductive foil 52 on which conductive bumps 51 are formed and an insulating resin layer 53 such as a semi-cured prepreg. The supply angle to the gap is shifted so as to follow the second roll 55. The supply angle of the laminate of the conductive foil 52 and the insulating resin layer 53 to the gap between the first roll 54 and the second roll 55 may be adjusted by the guide rolls 64a and 64b. At this time, the direction of the force applied to the conductive bump formed on the conductive foil 52 is adjusted so as to be as equal as possible to the axial direction of the conductive bump, that is, the direction of the conductive foil. Is preferred. By doing so, for example, when the aspect ratio of the substantially conical conductive bump is large, it is possible to prevent the conductive bump from being peeled off or deformed from the conductive foil.

  Further, in the case of manufacturing a plurality of types of printed wiring boards in which the sizes of the conductive bumps 51 are different by making the guide rolls 64a and 64b variable and adjusting the intrusion angle into the gap between the two rolls. In addition, the conductive bumps 51 can be uniformly penetrated regardless of the size and shape of the conductive bumps 51.

  Furthermore, by shifting the supply angle of the laminated body so as to follow the second roll 55, the contact area between the laminated body and the second roll 55 can be increased. Therefore, before passing through the gap between the first roll and the second roll, preliminary heating of the laminate of the conductive foil 52 and the insulating resin layer 53 can be performed by the second roll, The insulating resin layer 53 can be penetrated by the conductive bumps more uniformly and smoothly, the quality of the printed wiring board to be formed can be improved, and the productivity can be improved.

  Reference Example 3 FIG. 17 is a diagram schematically showing the configuration of a printed wiring board manufacturing apparatus according to still another reference example.

  This printed wiring board manufacturing apparatus is an apparatus for laminating a conductive foil and an insulating resin sheet such as a prepreg, and holding means 82 having a flat suction surface 81 for holding the insulating resin sheet 53. The conductive foil 52 is accommodated, the accommodating chamber 84 having side surfaces, and the holding means 82 that retains the insulating resin sheet 53 are introduced into the accommodating chamber 84 through the opening 83, and Means (not shown) for moving the insulating resin sheet 53 on the conductive foil 52 and pressure adjusting means for adjusting the pressure in the storage chamber 84 to be higher than the pressure outside the storage chamber ( And a cleaning means 87 disposed on the outside of the opening 83 of the storage chamber 84 and for cleaning the surface of the insulating resin sheet 53 opposite to the surface adsorbed by the holding means 82. It is those provided with the.

  FIG. 18 is a diagram schematically showing an example of the structure of the holding means 82 having the planar suction surface 81. A large number of suction holes 89 are formed in the suction surface 81, and the surface opposite to the suction surface 81 is decompressed. It is necessary to form the hole formed by the suction surface 81 so that the insulating resin sheet 53 such as a prepreg can be held as flat as possible. This is because if the insulating resin sheet 53 is wrinkled, the resin powder scatters from that portion and contaminates the surroundings. For example, the adsorption surface 81 may be formed with many fine holes in a stainless steel plate, or the adsorption surface may be formed of a porous material.

  The storage chamber 84 is a space for holding the conductive foil 52 laminated with the insulating resin sheet 53 held and supplied by the holding means 82. The storage chamber 84 is adjusted so that the internal atmospheric pressure is higher than the external atmospheric pressure, and has a structure that prevents intrusion of prepreg powder or the like from the outside of the storage chamber 84 into the storage chamber 84.

  The accommodation chamber 84 has an opening 83 for introducing the holding means 82 holding the insulating resin sheet 53. The opening 83 may be formed in accordance with the size and shape of the holding means 82.

  Openings 88a and 88b are formed on opposite side surfaces near the bottom surface of the storage chamber. The opening 88a is for introducing the conductive foil into the housing chamber, and the other opening 88b is for discharging the laminate of the conductive foil and the insulating resin sheet. The laminated body discharged from the opening 88b may be introduced into, for example, the printed wiring board manufacturing apparatus shown in FIGS.

  A cleaning means 87 for cleaning the surface of the insulating resin sheet 53 opposite to the surface adsorbed by the holding means 82 is provided adjacent to the outside of the opening 83 of the storage chamber 84. An example of the form of the cleaning means 87 is a vacuum suction machine. In this case, the suction force of the cleaning means 87 must be made smaller than the suction force by the holding means 82.

  In the printed wiring board manufacturing apparatus shown in FIG. 18, the holding means 82, the suction surface 81, the storage chamber 84, the cleaning means 87, etc. are charged by friction or the like, and adsorb prepreg powder or the like. In order to prevent this, it is held at the ground potential.

  The operation of the printed wiring board manufacturing apparatus having such a configuration will be described.

  First, the holding means 82 sucks and holds the insulating resin sheet 53 stocked at a predetermined place.

  On the other hand, a conductive foil 52 in which, for example, conductive bumps 51 are formed is introduced into the accommodation chamber 84 maintained at a higher atmospheric pressure than the surroundings through the opening 88a.

  The holding means 82 holding the insulating resin sheet 53 on the flat suction surface 81 is introduced into the storage chamber 84 through the opening 83 of the storage chamber 84 by a moving means (not shown). At this time, the surface opposite to the surface held by the suction surface 81 of the insulating resin sheet 53 is resin powder by a cleaning means 87 such as vacuum suction provided along the outside of the opening 83 of the storage chamber 84. Such contamination is removed and cleaned. At this time, since the holding means 82, the suction surface 81, the storage chamber 84, the cleaning means 87 and the like are held at the ground potential, contamination such as resin powder can be effectively removed.

  The insulating resin sheet introduced into the storage chamber 84 is laminated with the conductive foil 52 after being aligned with the conductive foil 52. After the lamination, the adsorption by the holding means is released, and the laminated body of the conductive foil 52 and the insulating resin sheet 53 is discharged from the opening 88b, for example, to the printed wiring board manufacturing apparatus shown in FIGS. After being introduced, the insulating resin sheet 53 is penetrated by the conductive bumps 51 formed on the conductive foil 52.

  Also, in the place where the insulating resin sheet is stocked, in order to prevent the powder of the resin constituting the insulating resin sheet from scattering to the surroundings, a space such as a storage chamber 84 is provided and the inside thereof is provided. You may make it hold | maintain.

  By adopting such a configuration, this printed wiring board manufacturing apparatus can significantly reduce the adhesion of an insulating resin powder such as a prepreg to the surface of a conductive foil such as a copper foil. Therefore, it is possible to suppress etching defects due to adhesion of such resin powder, generation of dents, and the like, improving the quality of the printed wiring board and improving productivity.

The figure which shows typically the structure of the apparatus which manufactures the printed wiring board of the state before using for the manufacturing apparatus which concerns on this invention. The figure which shows schematically the example of the processing flow of the control system of the manufacturing apparatus of the printed wiring board shown in FIG. The figure which shows schematically the example of a structure of the control system of the manufacturing apparatus of the printed wiring board shown in FIG. The figure which shows a mode that a conductive paste is printed on conductive foil with a printing means. The figure which shows schematically the mode of the conductive bump formed when the conductive paste 18 is printed on the conductive foil 17 in multiple times. The figure which shows the example of a structure of the manufacturing apparatus of the printed wiring board provided with the drying means on the circulation system path of the circulation means. The figure which shows schematically the structure of another apparatus which manufactures the printed wiring board of the state before using for the manufacturing apparatus which concerns on this invention. The figure which shows schematically the example of the more concrete structure of the manufacturing apparatus of the printed wiring board shown in FIG. The perspective view which shows roughly the example of a structure of the manufacturing apparatus of the printed wiring board which concerns on a basic reference example . FIG. 10 is a lateral view and a top view schematically showing the printed wiring board manufacturing apparatus shown in FIG. 9. In the manufacturing apparatus of printed wiring board according to implementation embodiments of the present invention, showing the structure of a pair of rolls performing the pressurization of the laminate schematically. The figure which shows the mode of distribution of the surface temperature of a roll when the winding density of the coil 62 in a rotary roll is made constant, and when it is small in a center part and enlarged at an edge part. The figure which shows schematically an example of the structure of the supply roll 57 of the release sheet with which the manufacturing apparatus of the printed wiring board which concerns on a reference example is provided. 13 schematically shows fluctuations in tension of the release sheet stretched between the supply roll and the first and second rolls when the supply roll capable of adjusting the tension as illustrated in FIG. 13 is used and when it is not used. Shown graphically. The figure which shows schematically the structure of the manufacturing apparatus of the printed wiring board concerning another reference example. The figure which expands and schematically shows the part of the 1st roll and 2nd roll of the manufacturing apparatus of the printed wiring board shown in FIG. The figure which shows schematically the structure of the manufacturing apparatus of the printed wiring board concerning another reference example. The figure which shows schematically the example of the structure of the holding means 82 which has the planar adsorption | suction surface 81. FIG. The figure which shows schematically the manufacturing process of the multilayer printed wiring board using the conventional electroconductive bump. The figure which shows schematically the example of a structure of the manufacturing apparatus of the printed wiring board which laminates | stacks the conventional conductive foil and the insulating resin layer.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Circulation means, 12 ... Printing means, 13 ... Discharge means, 14 ... Conductive bump, 15 ... Pit, 16 ... Metal mask, 17 ... Conductive foil, 18 ... Conductive paste, 19 ... Squeegee, 20 ... Drying means , 31 ... Sorting type input direction changer, 32a, 32b ... Stock conveyor, 33a, 33b ... Conductive foil input machine, 34a, 34b ... Discharge conveyor, 35a, 35b ... Direction changer, 36a, 36b ... Conveyor, DESCRIPTION OF SYMBOLS 51 ... Conductive bump, 52 ... Conductive foil, 53 ... Insulating resin layer, 54 ... 1st rotation roll, 55 ... 2nd rotation roll, 56 ... Release sheet, 57 ... Release sheet supply roll, 58 ... release sheet winding roll, 59, 60 ... guide roll (release sheet), 61 ... adjusting means, 62 ... coil, 63 ... transport roll, 64a, 64b ... guide roll, 81 ... suction surface, 82 Holding means, 83 ... opening, 84 ... accommodating chamber 87 ... cleaning means, 88a ... opening (introduction), 88b ... opening (discharge), 89 ... suction holes.

Claims (5)

A printed wiring board in which a conductive foil having a substantially conical conductive bump formed on a first surface and a semi-cured insulating resin sheet are laminated, and the insulating resin sheet is penetrated by the conductive bump. Manufacturing equipment,
A first roller;
A second roller disposed in parallel with the first roller and the rotation axis with a predetermined gap;
The conductive foil, the insulating resin sheet, and the release sheet, the insulating resin sheet being sandwiched between the first surface of the conductive foil and the release sheet, the first Means for supplying the roller so as to pass through a gap between the second roller and the second roller;
The rotation speed of the first roller and the second roller, and the supply speed of the conductive foil, the insulating resin sheet, and the release sheet supplied so as to pass through the gap between these rollers are: Driving means for driving the first roller and the second roller to be synchronized;
Adjusting means for adjusting the size of the gap between the first roller and the second roller so that the conductive bump penetrates the insulating resin layer ;
The first roller and the second roller have heating means inside, and cause non-uniformity in the gap distribution in the width direction between the first roller and the second roller by expansion deformation due to heating. A printed wiring board manufacturing apparatus, characterized by having a hollow structure . The first b over La and second B over La of the heating means, the printed wiring board according to claim 1, characterized in that provided uniformly to so that the temperature distribution in the width direction Manufacturing equipment. To claim 1, characterized by further comprising means you supplied into the gap between the release sheet and the second roller and the first roller mold release sheet to be so that a constant tension in the The printed wiring board manufacturing apparatus described. Claim 1, wherein said as contact area of the conductive foil and said first roller is increased, further comprising means you supplied along the conductive foil to the first roller A printed wiring board manufacturing apparatus according to claim 1. A printed wiring board in which a conductive foil having a substantially conical conductive bump formed on a first surface and a semi-cured insulating resin sheet are laminated, and the insulating resin sheet is penetrated by the conductive bump. A manufacturing method comprising:
A heating means therein, and the gap distribution in the width direction by the expansion deformation by heating has a hollow structure so as not to cause non-uniform, the rotary shaft is disposed kept parallel to each other In one roller and the second roller , the heating means works,
In the gap between the first roller and the second roller , the conductive foil, the insulating resin sheet, and the release sheet, and the insulating resin sheet on the first surface of the conductive foil And a release sheet, and is supplied so as to pass through the gap between the first roller and the second roller.

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