JP5080892B2 - Laminate production method - Google Patents

Description

  The present invention relates to a manufacturing facility for a laminated board used for manufacturing a printed wiring board.

  Conventionally, a general copper-clad laminate is obtained by placing a metal foil such as a copper foil above and below a prepreg obtained by impregnating a base material such as a glass cloth with a thermosetting resin varnish and drying by heating. It is manufactured by heat and pressure molding (see Patent Documents 1 and 2).

In recent years, with the miniaturization, weight reduction, multifunctionalization, and the like of personal computers, mobile phones, digital cameras, etc., there is an increasing demand for higher density printed wiring boards. In such a background, when manufacturing a thin copper foil, there is a problem that the yield is deteriorated because wrinkles easily enter. That is, in the case of using a copper foil having a thickness of 18 μm or more that has been conventionally used, the generation of wrinkles has not been a major problem due to the strength of the stiffness of the copper foil itself, but in recent years the density of printed wiring boards has increased. As a result, the copper foil having a thickness of 12 μm or less has been used, and the resistance of the copper foil to wrinkles has been weakened, and the deterioration of yield due to wrinkles has become a problem.
JP-A-57-203548 JP-A-4-53714

  It is considered that the occurrence of wrinkles on the copper foil during the production of the laminate as described above is caused by welding of the prepreg and the copper foil before the heat and pressure molding. That is, when such welding occurs, it is presumed that stress is generated between the prepreg and the copper foil due to stretching of the copper foil or hardening shrinkage of the prepreg that occurs at the time of heat and pressure molding, and wrinkles are generated.

  The present invention has been made in view of the above points, and by reliably preventing the occurrence of welding between the prepreg and the copper foil before heat and pressure molding, It is an object of the present invention to provide a method for manufacturing a laminated board that can suppress the generation of wrinkles and improve the yield.

The manufacturing method of the laminated board which concerns on Claim 1 is a manufacturing method of the laminated board which manufactures a laminated board by heat-pressing the laminated body 1 which laminated | stacked the prepreg and the metal foil of thickness 12 micrometers or less, Comprising: The said laminated body 1 is temporarily kept in the vicinity of the heat press device 2 to which heat from the heat press device 2 is transmitted , and the laminate 1 is cooled and held at a temperature not higher than 5 ° C. below the softening point of the prepreg. It includes a standby process and a heating press process in which the standby laminate 1 is supplied to the hot press apparatus 2 to perform the hot pressing.

  The invention according to claim 2 is the invention according to claim 1, wherein the metal plate is placed on both sides of the laminate 1 in the standby step and the hot press step, and the metal plate is placed before the standby step. It is characterized in that it is cooled in advance to a temperature not higher than 5 ° C. below the softening point of the prepreg.

  According to the first aspect of the present invention, the laminate 1 can be manufactured by heat-pressing the laminate 1 using the hot press apparatus 2 in the hot press step, and the laminate 1 is hot-pressed. While waiting in the vicinity of the heating press device 2 before, it is prevented that the temperature of the laminated plate is heated by the heat transmitted from the heating press device 2 and exceeds a temperature lower by 5 ° C. than the softening point of the prepreg. It is possible to suppress the prepreg from softening and welding of the prepreg and the metal foil before heat-press molding. Thereby, it can prevent that a metal foil produces a wrinkle at the time of heat press molding, and can improve a production yield.

  According to the invention which concerns on Claim 2, when a metal plate is piled up on both sides of the laminated body 1 and it heat-presses, a prepreg softens with the heat | fever transmitted from a metal plate in a stand-by process, and a prepreg and metal foil become. For example, when the metal plate is repeatedly used, even if the metal plate is washed with hot water or hot water, the metal plate prevents the welding from occurring. It is something that can be done.

  Hereinafter, the best mode for carrying out the present invention will be described.

  1 and 2 show an example of a production facility for producing a laminated board. This manufacturing facility includes a combination chamber 5, a transfer device 4, a standby unit 3, and a hot press device 2.

  The combination chamber 5 includes appropriate means for forming the laminate 1 by laminating prepreg and metal foil, and appropriate air conditioning equipment for adjusting the atmospheric temperature in the combination chamber 5.

  The conveying device 4 conveys the laminate 1 from the combination chamber 5 to the standby unit 3 and is configured by an appropriate device such as a belt conveyor or a roller conveyor.

  The standby unit 3 is provided in the vicinity of the heating press device 2 and includes a mounting table 7 on which the laminate 1 transported by the transport device 4 is placed. The standby unit 3 is provided with a standby space 6 that is recessed below the transport path of the laminate 1 by the transport device 4, and the mounting table 7 is moved up and down in the standby space 6 by a hydraulic mechanism or the like. It is formed to be drivable. For safety, it is preferable that the standby unit 3 is covered with a non-combustible sheet 8 except for a portion through which the laminate 1 passes.

  Further, a cooling device 11 for cooling the inside of the standby space 6 of the standby unit 3 is provided. At this time, for example, an appropriate cooling device 11 that generates cold air and the inside of the standby space 6 are connected by the duct 12, and the cold air generated by the cooling device 11 is supplied into the standby space 6 through the duct 12. It can be so.

  The hot press apparatus 2 heats and press-molds the laminate 1 or presses the laminate 1 or the combined body 9 to form a laminate. This hot press apparatus 2 can be formed, for example, by providing a pair of hot plates 10 that heat and press the laminate 1 or the combination 9 at a predetermined pressure and temperature.

  In the manufacturing method of the laminated board in this embodiment, a laminated board is manufactured by using a manufacturing facility as exemplified above, and sequentially performing a combination process, a conveying process, a standby process, and a heating press process.

  A combination process is a process of forming the laminated body 1 which laminated | stacked the prepreg and metal foil.

  In this step, first, one prepreg or two or more prepregs are laminated in the combination chamber 5, but the laminate 1 is configured by overlapping metal foils on the outer surfaces on both sides. At this time, it is preferable to further dispose metal plates on both sides of the laminate 1. Alternatively, the laminate 1 and the metal plate may be alternately stacked in a plurality of stages, and the metal plate may be stacked on the outermost layer.

  As said metal foil and prepreg, the appropriate thing which can be used for the manufacture use of a laminated board can be used, For example, a copper foil can be used as a metal foil, and a glass substrate epoxy resin prepreg can be used as a prepreg. As the metal plate, for example, a stainless steel plate having a mirror-finished surface can be used.

  While the laminate 1 is formed in the combination chamber 5, it is preferable to suppress the progress of the prepreg curing reaction by adjusting the atmospheric temperature in the combination chamber 5 to an appropriate temperature by the air conditioning equipment.

  Next, in the transporting process, the one or more layers of the laminate 1 formed in this way are supplied to the transport device 4, and the stack 1 is transported to the standby unit 3 by the transport device 4 (FIG. 1 ( a)). The laminate 1 in FIGS. 1 and 2 includes both a case where the laminate 1 has only one stage and a case where the laminate 1 is a laminate of a plurality of stages.

  Next, in the standby process, the laminate 1 transported in the transport process is temporarily waited by the standby unit 3 in the vicinity of the hot press apparatus 2. Here, in the present embodiment, the transported single-stage or multi-stage laminate 1 is sequentially transported to the standby unit 3. At this time, each stack 1 is sequentially supplied onto the mounting table 7 and the mounting table 7 is driven downward every time the stack 1 is supplied, so that the position at which the stack 1 is supplied is kept constant. . Thereby, on the mounting table 7, a combined body 9 is formed in which a plurality of stacked one-stage or multi-layer stacks 1 are combined and the combined body 9 is arranged in the standby space 6, and the standby space 6 (See FIG. 1B).

  In this standby step, the combined body 9 is cooled by the cooling device 11 to maintain the temperature of the laminate 1 at a temperature not higher than 5 ° C. below the softening point of the prepreg. For this reason, the temperature rise of the laminated body 1 by the heat transmitted from the hot press apparatus 2 is suppressed.

  After completion of the standby, the combined body 9 is supplied from the standby unit 3 to the heating press device 2. At this time, when the mounting table 7 is driven upward, the combined body 9 is disposed above the standby space 6, and in this state, the combined body 9 is supplied to the hot press apparatus 2 using appropriate pushing means or the like (FIG. 2 (a)).

  In the hot pressing step, the laminate 1 supplied from the standby unit 3 is hot pressed, and in the present embodiment, the combination 9 is hot pressed (see FIG. 2B).

  The hot press conditions are appropriately set according to the type of prepreg and metal foil constituting the laminate 1. In this heating press process, the resin component constituting the prepreg is softened and then thermally cured to form an insulating layer, and the metal foil is in close contact with the insulating layer to form a conductor layer with the metal foil. A laminated board is obtained. The obtained laminated board is taken out from the hot press apparatus 2.

  Also during this hot pressing process, the laminate 1 is supplied to the standby unit 3 by the above-described process to form the combined body 9, and the combined body 9 is put into the standby unit 3 until the hot pressing process is completed. And wait. And after the said heat press process is complete | finished, the combination 9 is newly supplied to the heat press apparatus 2 from the waiting | standby part 3, and a heat press is performed (refer FIG. 1, 2). In this way, the laminates can be manufactured sequentially.

  When the laminate is manufactured as described above, in the standby step, the laminate 1 is cooled to maintain the temperature of the laminate 1 at a temperature not more than 5 ° C. lower than the softening point of the prepreg. While another laminate 1 supplied to the heating press process before the laminate 1 waiting in the process is being heated and pressed, the heat generated in the heating press process waits in the standby process. Even when it is transmitted to the laminate 1, the temperature rise of the laminate 1 can be suppressed and welding between the prepreg and the metal foil can be prevented.

  Here, the softening point of the prepreg can be measured as follows. First, in a state where a constant load in the thickness direction is applied to the prepreg, the prepreg is heated to raise the temperature. The change in thickness of the prepreg with respect to temperature is measured with a micro gauge or the like. Thereby, a temperature-thickness curve as shown in FIG. 3 is obtained. In this temperature-thickness curve, even before the prepreg is softened, even if the temperature rises, the change in thickness is almost not seen, and when the prepreg starts to soften, the thickness gradually decreases and the rate of change Will rise, and will eventually fall linearly with a certain gradient. The softening point is derived as the temperature at which a straight line obtained by extending a straight portion before softening in this curve intersects with a straight line obtained by extending a portion having a constant gradient after softening.

  When the temperature of the prepreg rises and softens, the prepreg and the metal foil adjacent to each other may be welded. At this time, since the prepreg starts to soften from a temperature lower than the softening point as shown in FIG. 3, such welding may occur even if the temperature of the prepreg is slightly lower than the softening point. However, in the present invention, as described above, the temperature of the laminate 1 is kept at a temperature not higher than 5 ° C. lower than the softening point of the prepreg, so that the temperature of the laminate 1 is lower than the temperature at which the prepreg starts to soften. The temperature can be maintained and welding between the prepreg and the metal foil can be reliably prevented.

  The lower limit of the holding temperature of the laminate 1 in this standby process is not particularly limited, but if this temperature is too low, the holding temperature may be 20 because the molding efficiency in the hot press process may be reduced. It is preferable that the temperature is at least ° C.

  Thus, in this invention, the temperature rise of the laminate 1 before being supplied to the hot press apparatus 2 is suppressed, and welding between the prepreg and the metal foil in the laminate 1 before hot pressing is prevented. Therefore, generation of wrinkles of the metal foil due to stretching of the copper foil at the time of heat and pressure molding, curing shrinkage of the prepreg, and the like can be prevented, and the yield at the time of manufacturing the laminate can be improved. In particular, even when the metal foil is thin and weak, such as when the thickness is 12 μm or less, such wrinkles can be prevented. For example, in the production line of a laminated board in which the defect occurrence rate due to the occurrence of wrinkles is about 13%, the defect occurrence rate is reduced to about 1% by cooling the laminate 1 in the standby process as in this embodiment. It is also possible to reduce to a minimum.

  Moreover, in order to make the laminated body 1 stand by in the vicinity of the heating press apparatus 2 in which a heating press process is made in a standby process, the laminated body supplied to the hot press process earlier than the laminated body 1 waiting in the standby process. After the heat and pressure molding 1 is completed, the laminate 1 in the standby process can be quickly supplied to the press molding apparatus, and then the heat and pressure molding can be performed continuously. Therefore, the laminate can be manufactured with high productivity.

  Also, when using a metal plate in the production of a laminated plate as described above, the metal plate is usually washed and used repeatedly after the production of the laminated plate. In order to prevent water droplets from remaining, washing with hot water or hot water is performed. In this case, since the temperature of the metal plate after washing becomes high, if this is used for the production of the laminated plate as it is, there is a risk that the prepreg and the metal foil are welded by transferring heat from the metal plate to the laminate 1. is there.

  Therefore, in the manufacturing process of the laminated plate, it is preferable to keep the metal plate at a temperature not more than 5 ° C. lower than the softening point of the prepreg by cooling the metal plate with an appropriate means in advance before the standby process. . For example, in the above embodiment, before the metal plate is stacked on the laminate 1 in the combination step, the metal plate is cooled in advance, so that the metal plate has a temperature lower than the softening point of the prepreg by 5 ° C. or less. The temperature is maintained. If it does in this way, it can prevent reliably that the welding between a prepreg and metal foil generate | occur | produces with the heat transmitted to the laminated body 1 from the above metal plates. At this time, the lower limit of the temperature of the metal plate is not particularly limited, but if this temperature is too low, the molding efficiency in the hot press process may be reduced, and therefore, the temperature is preferably 20 ° C. or higher. .

(A) And (b) is the schematic which shows an example of the manufacturing process of a laminated board. (A) And (b) is the schematic which shows an example of the manufacturing process of a laminated board. It is a graph which shows the example of the temperature-thickness curve measured when it heats up in the state which applied a fixed load to the prepreg.

Explanation of symbols

1 Laminate 2 Heating press

Claims (2)

A method for manufacturing a laminate by heating and pressing a laminate obtained by laminating a prepreg and a metal foil having a thickness of 12 μm or less , wherein the laminate presses heat from the heating press device. A standby step of temporarily waiting in the vicinity of the substrate and cooling the laminate to maintain it at a temperature not higher than 5 ° C. below the softening point of the prepreg, and supplying the standby laminate to a heating press device. And a heating press process for performing a heating press.   In the standby process and the hot press process, the laminate is in a state where metal plates are stacked on both sides thereof, and the metal plate is cooled in advance before the standby process, and is 5 ° C. lower than the softening point of the prepreg. The method for producing a laminated board according to claim 1, wherein the temperature is set to a temperature equal to or lower than the temperature.

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