JP3997585B2 - Multilayer board manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a multilayer board used in electrical / electronic devices and the like.
[0002]
[Prior art]
Multilayer boards are used in the production of printed wiring boards used in electrical and electronic equipment. This multilayer board is a stack of adhesive sheets made into a sheet by impregnating a base material with a thermosetting resin composition called a prepreg on the front and back of one or a plurality of inner layer substrates having a conductor circuit formed on the surface, Further, a metal foil is disposed on both outer sides to form a pressure-bonded body, and then the pressure-bonded body is sandwiched between flat plates, further sandwiched between pressure plates of a molding press, and heated by heat transfer from the pressure plates. It is manufactured by pressurizing with the pressure between the pressure plates.
[0003]
In order to improve productivity, as shown in FIG. 2, a pressure-bonded body 14 in which an inner layer substrate 11, a prepreg 12, and a metal foil 13 are stacked so that the metal foil 13 is disposed on both outer sides thereof is provided. The laminated body 10 is formed by stacking a plurality of plates 18 in the vertical direction with the flat plate 18 interposed therebetween, and the laminated body 10 is sandwiched between the pressure plates 19 and 19 and heated and pressed to obtain a large number of multilayer plates at a time. The method is generally done.
[0004]
As a method of stacking these inner layer substrate 11, prepreg 12, metal foil 13, and flat plate 18 to form the laminate 10, it is performed by a method of stacking in order from the lower side to the upper side. In the case of the two-layer configuration, the metal foil 13 is stacked on the lowermost flat plate 18, and then the required number of prepregs 12 are stacked thereon, and then the inner layer substrate 11 is stacked thereon, and then the upper layer. After the required number of prepregs 12 are overlaid, the metal foil 13 is overlaid thereon, and then the flat plate 18 is overlaid thereon, so that the portion corresponding to the lower pressure plate 19 corresponds to the upper pressure plate 19. A method of overlapping in order toward the part is performed.
[0005]
However, in the case of being manufactured in such a manner, a stripe-shaped recess generally called “wrinkle” may be formed in the metal foil 13 on the surface of the obtained multilayer board. This is because the surface of the prepreg 12 has irregularities due to variations in the amount of the thermosetting resin composition, and the metal foil 13 laminated with the prepreg 12 is considered to have irregularities. When the unevenness of the metal foil 13 is not sufficiently expanded when sandwiched between the pressure plates 19 and 19 and heated and pressed, it is considered that a streak-like recess is formed.
[0006]
In addition, when the inner layer substrate 11 is sandwiched, compared to a case where the inner layer substrate 11 having a conductor circuit formed on the surface is not sandwiched, a streak-shaped recess is particularly easily formed. This is because, when the inner layer substrate 11 having a conductor circuit formed on the surface is sandwiched, the position corresponding to the portion where the conductor circuit is formed and the position corresponding to the portion where the conductor circuit is not formed are arranged between the pressure plates 19 and 19. A difference in pressure applied to the metal foil 13 when heated and pressed between the two is generated, and a streak-like recess is easily formed in the metal foil 13 at a position corresponding to a portion without a conductor circuit having a relatively low pressure. It is considered because.
[0007]
Furthermore, in the case of a method for obtaining a plurality of multilayer boards at a time by stacking a plurality of the objects to be bonded 14 in the vertical direction, a conductor circuit is formed on each inner layer substrate 11 stacked in each object 14 to be bonded. Since the formed part and the non-formed part almost overlap at the same position, the difference in pressure between the part where the conductor circuit is formed and the part where the conductive circuit is not formed becomes particularly large, and the streak-shaped recess is particularly easily formed. It has become.
[0008]
When a conductor circuit is formed by etching the metal foil on the surface using the multilayer board having the streak-like recesses, the part where the streak-like recesses are formed is likely to be disconnected, and the yield of the printed wiring board is increased. There was a problem of being low. Therefore, there is a demand for a method for producing a multilayer board in which streak-like recesses are unlikely to be formed in the metal foil on the surface of the resulting multilayer board.
[0009]
[Problems to be solved by the invention]
The present invention was made in order to improve the above-mentioned problems. The object of the present invention is to provide a substrate for an inner layer having a conductor circuit formed on the surface, a prepreg comprising a thermosetting resin composition and a base material. Multilayers produced by stacking a plurality of pressure-bonded bodies stacked with metal foils so that the metal foils are arranged on both outer sides of the metal foil and sandwiching the plates to form a laminate, and heating and pressing the laminate An object of the present invention is to provide a method for manufacturing a multilayer plate, in which streaky recesses are not easily formed in the metal foil on the surface of the resulting multilayer plate.
[0010]
[Means for Solving the Problems]
A method for producing a multilayer board according to claim 1 of the present invention comprises a substrate for an inner layer having a conductor circuit formed on a surface thereof, a prepreg composed of a thermosetting resin composition and a base material, and a metal foil on both outer sides thereof. A multilayer board manufacturing method for manufacturing a multilayer body by stacking a plurality of pressure-bonded bodies stacked on a predetermined position so that a metal foil is disposed between sandwiched flat plates, and heating and pressing the multilayer body In the method of stacking the metal foil on the lower side of the metal foil forming the object to be bonded and the flat plate on a predetermined position, the metal foil is stacked on the upper side of the flat plate, and then the flat plate and the metal foil are pressed. It is characterized by a method of releasing the pressure applied to the flat plate and the metal foil after the curved object is overlaid on a predetermined position.
[0011]
The multilayer board manufacturing method according to claim 2 of the present invention is the multilayer board manufacturing method according to claim 1, wherein the method of stacking the curved objects is already overlaid on a predetermined position where the curved objects are to be stacked. It is characterized in that it is a method of stacking curved objects while discharging the load.
[0012]
The method for producing a multilayer plate according to claim 3 of the present invention is the method for producing a multilayer plate according to claim 1 or claim 2, wherein the method of overlapping the upper metal foil among the metal foils forming the object to be bonded is as follows. Pressurize the load already stacked on the predetermined position where the metal foil is to be stacked and bend it in a convex shape, then stack the metal foil on the curved load, and then the metal The method is characterized by releasing the pressure applied to the metal foil and the load while applying vibration to the foil and the load.
[0013]
The multilayer board manufacturing method according to claim 4 of the present invention is the multilayer board manufacturing method according to claim 3, wherein pressure is applied to the metal foil and the load while applying vibration to the metal foil and the load. The method in which the metal foil and the load are vibrated, the pressed object is brought into contact with the central portion of the surface of the metal foil, and then the metal foil is scanned in the direction of the end while the pressed object is kept in contact therewith. And a method of releasing pressure on the metal foil and the load while applying vibration to the load.
[0014]
According to the present invention, when the pressurization to the concavely curved flat plate and the metal foil is released, the metal foil is subjected to a force that extends toward the outside due to the force that the flat plate attempts to flatten. The unevenness is flattened. Therefore, when a multilayer board is manufactured by heating and pressurizing, the metal foil is stretched, so that it becomes difficult to form streak-like recesses in the metal foil on the surface of the obtained multilayer board.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The manufacturing method of the multilayer board concerning this invention is demonstrated based on drawing. FIG. 1 is a front view for explaining a main part of a process of an embodiment of a method for producing a multilayer board according to the present invention, and FIG. 2 explains an embodiment of a method for producing a multilayer board according to the present invention. FIG. 3 is an exploded front view for explaining a modification of FIG. FIG. 4 is a plan view for explaining an embodiment of a method for producing a multilayer board according to the present invention, and FIG. 5 is a front view for explaining a main part of an embodiment of the method for producing a multilayer board according to the present invention. FIG. 6 is a front view for explaining a main part of another embodiment of the method for producing a multilayer board according to the present invention.
[0016]
As shown in FIG. 2, in one embodiment of the method for producing a multilayer board according to the present invention, an inner layer substrate 11, a prepreg 12, and a metal foil 13 are disposed on both outer sides. In this method, a plurality of the pressure-bonded bodies 14 stacked in this manner are stacked between flat plates 18 to form a laminated body 10, and the laminated body 10 is heated and pressed to produce the multilayer board.
[0017]
The inner layer substrate 11 used in the present invention is not particularly limited as long as it is a plate having a conductor circuit formed on its surface. For example, epoxy resin-based, phenol resin-based, polyimide resin-based, unsaturated polyester resin-based, polyphenylene Thermosetting resins such as ether resins, and boards made by blending these thermosetting resins with inorganic fillers, inorganic fibers such as glass, cloths made of organic fibers such as polyester, polyamide, cotton, and paper What formed the conductor circuit on the board which adhere | attached the material with the said thermosetting resin etc. is mentioned. The position where the conductor circuit is formed is not limited to the surface but may also be formed inside. The inner layer substrate 11 may have a hole formed with a metal film on the wall surface.
[0018]
The prepreg 12 used in the present invention is composed of a thermosetting resin composition and a substrate. For example, after adjusting the viscosity by adding a solvent to the thermosetting resin composition, the substrate is immersed in the liquid. Impregnated and then heated to dry the solvent and semi-cure the thermosetting resin composition, or a base material in a state where the solid thermosetting resin composition is heated and melted at room temperature It is obtained by applying to and impregnating. The thermosetting resin composition in the prepreg 12 is limited to a semi-cured (B stage) state.
[0019]
As the substrate, inorganic fibers such as glass, organic fibers such as polyester, polyamide, polyacryl, and polyimide, and natural fibers such as cotton, woven fabric, nonwoven fabric, and paper can be used. Use of glass fiber woven fabric (glass cloth) is preferable because a multilayer board having excellent heat resistance and moisture resistance can be obtained. In general, a substrate having a thickness of 0.04 to 0.30 mm is used.
[0020]
In addition, as the thermosetting resin composition, an epoxy resin type, a phenol resin type, a polyimide resin type, an unsaturated polyester resin type, a polyphenylene ether resin type or the like alone, a modified product, a mixture, a thermosetting resin, etc. The entire composition can be used. In addition, when a thermosetting resin composition is an epoxy resin type | system | group, the balance of an electrical property and adhesiveness is favorable and preferable.
[0021]
The thermosetting resin composition contains a thermosetting resin as an essential component, and can contain a curing agent, a curing accelerator, an inorganic filler, a solvent, and the like of the thermosetting resin as necessary. . Note that a thermosetting resin composition having a low self-curing property such as an epoxy resin needs to contain a curing agent for curing the resin.
[0022]
The amount of the thermosetting resin composition in the prepreg 12 is preferably 40 to 70 parts by weight with respect to 100 parts by weight of the total weight of the thermosetting resin composition and the substrate. If the amount is less than 40 parts by weight, bubbles may remain in the resulting multilayer board and the electrical characteristics may deteriorate. If the amount exceeds 70 parts by weight, the thickness of the resulting multilayer board varies greatly. There is a case.
[0023]
Moreover, as metal foil 13 used for this invention, if it is metal foil, it will not specifically limit, Single, alloy, and composite foil, such as copper, aluminum, brass, nickel, can be used. The thickness of the metal foil 13 is generally 0.012 to 0.070 mm. A layer of a thermosetting resin composition may be formed on one side of the metal foil 13. In this case, the thermosetting resin composition layer is laminated so as to be in contact with the prepreg 12.
[0024]
As a method of forming the laminate 10 by stacking these inner layer substrate 11, prepreg 12, metal foil 13 and flat plate 18, as shown in FIG. 4, the flat plate 18 having the metal foil 13 previously stacked on the upper surface is laminated. After transporting (loading a) to a predetermined position A where the body is to be formed, the intermediate body 15 formed by previously superimposing the inner layer substrate 11 and the prepreg 12 thereon is transported (loading b). Then, after carrying the metal foil 13 on the intermediate body 15 (c) and loading it, carrying the flat plate 18 having the metal foil 13 previously laminated on the metal foil 13 in advance (of a Transport) Stack, and if necessary, carry the intermediate body 15 and the flat plate 18 with the metal foil 13 previously stacked on the upper surface in order. In addition, at the position B where the metal foil 13 is previously superimposed on the upper surface of the flat plate 18, the flat plate 18 is transported (x transport) and the metal foil 13 is transported (y transport) simultaneously with the transport of a, b, c. The metal foil 13 is superposed on the upper surface of the flat plate 18.
[0025]
In addition, when the flat plate 18 on which the metal foil 13 is previously stacked is transported to a predetermined position A where a laminated body is to be formed, as shown in FIG. After laminating the lower metal foil 13a among the metal foils forming the plate 14, as shown in FIG. 1 (b), the flat portion 18 and the central portion of the metal foil 13a are pressed to bend into a concave shape, As shown in 1 (c), after this curved object 16 is overlaid on a load 17 that has already been superimposed on a predetermined position, by releasing the pressure on the flat plate 18 and the metal foil 13a, As shown in FIG. 1D, the curved object 16 is planarized.
[0026]
The flat plate 18 is preferably a metal plate such as iron or stainless steel or a surface obtained by insulating the surface of these metal plates. Since the rigidity of these flat plates 18 is higher than that of the metal foil 13a, when the pressurization to the flat plate 18 and the metal foil 13a is released, the force that the flat plate 18 tries to flatten is shown in FIG. As shown, the metal foil 13a is subjected to a force extending toward the outside (in the direction of the arrow in the figure), and the unevenness of the metal foil 13a is planarized. Therefore, when a multilayer plate is manufactured by heating and pressurizing the laminate formed in this way, the metal foil 13a is stretched, so that a streak-shaped recess is formed in the metal foil on the surface of the obtained multilayer plate. It becomes difficult to be done.
[0027]
As a method of forming the curved body 16 by pressurizing the flat plate 18 and the metal foil 13a to bend into a concave shape, for example, as shown in FIG. In the state of being held by the flat plate holding claws 21, the flat plate warping cylinder 23 is extended downward to pressurize the central portion of the flat plate 18 and the metal foil 13 a to bend into a concave shape to form the curved object 16. When the curved object 16 is stacked on the load 17 that has already been stacked on a predetermined position, the curved object 16 is moved downward by extending the curved object lifting cylinder 25 to move the load 16 downward. 17 on top. Then, by retracting the claw moving cylinder 27 to the side, the flat plate holding claw 21 is pulled out to the side, and by pressing the flat plate warping cylinder 23 upward, the pressurization is stopped to flatten the flat plate 18 and the metal foil 13a. To do.
[0028]
In addition, when the load 17 already stacked on a predetermined position where the curved object 16 is to be stacked is charged, when the curved object 16 is stacked, static electricity is transmitted to the metal foil 13a and the metal foil 13a is charged. Since the unevenness may be formed, when the curved object 16 is stacked on the load 17, when the curved object 16 is stacked while the charge of the load 17 is removed, a streak-shaped recess is formed on the metal foil on the surface. A multilayer board that is particularly difficult to form is obtained and preferred. Examples of the method for eliminating static electricity include a method in which a grounded metal object is brought into contact, and a method in which air for removing static electricity is blown.
[0029]
Further, when the upper metal foil 13b of the metal foil 13 forming the object to be bonded 14 is overlapped, the central portion of the load 17 already stacked on a predetermined position where the metal foil 13b is to be stacked is used. After pressurizing and curving into a convex shape, the metal foil 13b is overlaid on the curved load 17 and then applying ultrasonic waves to the metal foil 13b and the load 17 to give vibration, When the metal foil 13b and the load 17 are overlapped by a method of releasing the pressurization, it is preferable to obtain a multilayer plate in which a streak-like recess is not easily formed on the metal foil on the surface.
[0030]
This is because the metal foil 13b superimposed on the load 17 curved in a convex shape is also curved in a convex shape. Therefore, when vibration is applied, the vibration force and gravity overlap and the metal foil 13b is outside (see FIG. This is considered to be because a force stretched in the direction of the arrow (5) is applied and the unevenness of the metal foil 13b is planarized.
[0031]
For example, as shown in FIG. 5, the load 17 is pressed and curved in a convex shape, and the end of the carrier plate 31 on which the load 17 is placed is held by the carrier plate holding claws 33 from above. In this state, by extending the carrier plate warping cylinder 35 upward, the central portion of the carrier plate 31 is pressurized and curved in a convex shape. When vibration is applied to the metal foil 13b and the load 17, the ultrasonic wave generation device 37 provided at the tip of the carrier plate warping cylinder 35 applies vibration to the metal foil 13b and the load 17 so that the metal foil 13b Planarize. In addition, the vibration given to the metal foil 13b and the load 17 is not limited to ultrasonic waves, and may be caused to vibrate by an eccentric motor or the like.
[0032]
In addition, when giving vibration to the metal foil 13b and the load 17, as shown in FIG. 6, the pressed object 39 was brought into contact with the center of the surface of the metal foil 13 b, and then the pressed object 39 was contacted. If the scanning is performed in the direction of the end portion, the unevenness of the metal foil 13b is further extended and particularly planarized by this scanning, so that it is preferable to obtain a multilayer plate in which streaky concave portions are not particularly easily formed on the metal foil on the surface. . The scanning of the pressing object 39 may be performed while applying vibration to the metal foil 13b and the load 17, or may be performed without applying vibration to the metal foil 13b and the load 17, but is performed while applying vibration. In particular, it is preferable to obtain a multilayer board in which streak-like recesses are hardly formed on the metal foil on the surface. Examples of the method of bringing the pressed object 39 into contact include a method of bringing a brush, a brush, a roll, or the like into contact with the metal foil 13b, or a method of blowing air.
[0033]
Then, after stacking as described above to form a laminate, as shown in FIG. 2, the laminate 10 is sandwiched between pressure plates 19 and 19 and heated and pressed to produce a multilayer plate. Examples of the heating / pressurizing method include a method in which the pressure plate 19 is heated and heated by heat transfer from the pressure plate 19, and a method in which the metal foil 13 is fed and heated by resistance heating. Note that resistance heating is a method in which power is supplied to a conductor having electrical resistance and heated by heat generated by the Joule effect. In addition, what is necessary is just to adjust suitably as heating conditions so that it may become the temperature which the thermosetting resin composition in the prepreg 12 hardens | cures.
[0034]
When the laminated body 10 is sandwiched between the pressure plates 19, 19, it may be heated / pressurized with a cushioning material such as cellulose paper or aramid fiber paper, a heat conduction adjusting material, or the like as necessary. Good.
[0035]
In addition, although the said embodiment demonstrated embodiment of the to-be-bonded body 14 which pinched | interposed the one board | substrate 11 for inner layers between the prepregs 12, the number of the board | substrates 11 for inner layers is not limited to one sheet, A plurality of inner layer substrates 11 may be vertically stacked with the prepreg 12 interposed therebetween, and the prepreg 12 may be disposed on both outer sides thereof to form a pressure-bonded body 14. As shown in FIG. A plurality of inner layer substrates 11 may be arranged in the horizontal direction between the prepregs 12 to form the pressure-bonded body 14. When a plurality of inner layer substrates 11 are arranged side by side in the horizontal direction, the intermediate body 15 is obtained by fixing the plurality of inner layer substrates 11 arranged in the horizontal direction with a fixed object such as an adhesive or an adhesive tape. Since the inner layer substrate 11 is less likely to move individually when transporting the metal foil or when the metal foil 13b and the load 17 are vibrated, the streaks caused by the individual movement of the inner layer substrate 11 are less likely to occur. Shaped recesses are less likely to be formed in the resulting metal foil on the surface of the multilayer board.
[0036]
Further, the number of the pressure-bonded bodies 14 sandwiched between the pressure plates 19 and 19 is not particularly limited as long as it is two or more, and more pressure-bonded bodies 14 are stacked with a flat plate 18 interposed therebetween. Also good.
[0037]
【The invention's effect】
In the method of manufacturing a multilayer board according to the present invention, a flat plate and a metal foil are pressed to bend into a concave shape, and then the curved object is stacked on a predetermined position, and then the pressurization to the flat plate and the metal foil is released. Since the lower metal foil is stacked among the metal foils that form the object to be bonded by this method, streak-like recesses are hardly formed on the metal foil on the surface of the resulting multilayer board.
[0038]
In the method for producing a multilayer board according to claim 3 of the present invention, the upper metal foil of the metal foil forming the object to be bonded is stretched and stacked. Is difficult to form.
[Brief description of the drawings]
FIG. 1 is a front view for explaining a main part of a process of an embodiment of a method for producing a multilayer board according to the present invention.
FIG. 2 is an exploded front view for explaining an embodiment of a method for producing a multilayer board according to the present invention.
FIG. 3 is an exploded front view for explaining a modification of FIG. 2;
FIG. 4 is a plan view for explaining an embodiment of a method for producing a multilayer board according to the present invention.
FIG. 5 is a front view for explaining a main part of an embodiment of the method for producing a multilayer board according to the present invention.
FIG. 6 is a front view for explaining a main part of another embodiment of the method for producing a multilayer board according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Laminated body 11 Inner layer board | substrate 12 Prepreg 13 Metal foil 13a Lower metal foil 13b among the metal foils which form a to-be-bonded body Upper metal foil 14 among the metal foils which form a to-be-bonded body 14 To-be-bonded body 15 Intermediate body 16 Curved object 17 Loaded object 18 Flat plate 19 Pressure plate 21 Flat plate holding claw 23 Flat plate warping cylinder 31 Carrier plate 33 Carrier plate holding claw 35 Carrier plate warping cylinder 37 Ultrasonic generator 39 Pressed object A Predetermined to form a laminate position

Claims (4)

A substrate for an inner layer having a conductor circuit formed on the surface, a prepreg composed of a thermosetting resin composition and a base material, and a metal foil are stacked on a predetermined position so that the metal foil is arranged on both outer sides. In the manufacturing method of the multilayer board which forms a laminated body by stacking a plurality of the bonded bodies sandwiched between flat plates and heats and pressurizes the laminated body, the lower side of the metal foil forming the bonded body The method of stacking the metal foil and the flat plate on the predetermined position is that the metal foil is stacked on the upper side of the flat plate, then the flat plate and the metal foil are pressed to bend into a concave shape, and then the curved object is put into the predetermined position. A method for producing a multilayer board, characterized by being a method of releasing pressure applied to the flat plate and the metal foil after being overlaid on top. 2. The multilayer board according to claim 1, wherein the method of stacking the curved objects is a method of stacking the curved objects while discharging the load already stacked on a predetermined position where the curved objects are to be stacked. Manufacturing method. The method of stacking the upper metal foil among the metal foils that form the object to be bonded is to pressurize the load already stacked on the predetermined position where the metal foil is to be stacked and to bend it into a convex shape. The method is characterized in that a metal foil is stacked on the curved load and then the metal foil and the load are released while applying vibration to the metal foil and the load. The manufacturing method of the multilayer board of Claim 1 or Claim 2. The method of releasing the pressure on the metal foil and the load while giving vibration to the metal foil and the load is that the pressed object contacts the center of the surface of the metal foil while giving the vibration to the metal foil and the load. After that, the pressed object is scanned in the direction of the edge while being in contact, and then the metal foil and the load are released while applying pressure to the metal foil and the load. The method for producing a multilayer board according to claim 3.

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