JP4277827B2 - Manufacturing method of laminate - Google Patents

Description

  The present invention relates to a method for manufacturing a laminated body used for manufacturing a multilayer wiring circuit board, and more specifically, when the inner layer circuit member and a prepreg are temporarily welded to form a laminated body, the temporary welded portion is generated. Used in the manufacture of multilayer wiring circuit boards to suppress the occurrence of misalignment between layers and the formation of concave portions in the outermost metal foil by suppressing the occurrence of concave portions. The present invention relates to a method for manufacturing a laminate.

  As a manufacturing method of a multilayer wiring circuit board, as described in the following Patent Document 1 and Patent Document 2, a plurality of inner layer circuit members are stacked via a prepreg, and the prepreg is attached to an adjacent inner layer circuit member. A method is known in which a laminated body is obtained by partial temporary welding, and the laminated body is formed by heating and pressing to weld each prepreg together with an adjacent inner layer circuit member.

  However, in the case of manufacturing a laminated body by the manufacturing method disclosed in Patent Document 1 and Patent Document 2, in order to press and weld the welding head and the inner layer circuit member directly, FIG. As shown, there is a problem that the temporary welding portion 5 becomes concave due to the pressing force of the welding head, and the periphery of the concave portion becomes slightly convex.

  Therefore, when a multilayer circuit board is manufactured using a conventional laminate in which a concave portion is formed in the welded portion, an inner layer is formed in the heat and pressure molding at the time of secondary lamination due to the presence of the concave portion and the surrounding convex portion. Deviations and distortions occurred between the circuit members, which caused a decrease in the positioning accuracy between the stacked layers.

  In addition, the presence of the concave portion is that when the metal foil is laminated on the outermost layer during the heat-press molding of the secondary lamination, the concave portion is transferred to the outermost metal foil and remains as it is. There was also a problem.

  On the other hand, the following Patent Document 3 discloses an inner layer welding machine for laying up a set of inner layer wiring boards with exposed prepregs on the surface, melting and welding the prepregs with a welding head, and fixing the inner layer wiring boards. The heat of the welding head is in direct contact with the prepreg by interposing Teflon tape or paper tape so that the welding head and the prepreg do not come into direct contact when welding the laminate whose outermost layer is a prepreg. A technique for preventing carbonization or softening of the prepreg surface and adhering to the tip of the welding head is disclosed.

However, in the technique described in Patent Document 3, since the welding head comes into contact with the prepreg via the tape, the shape of the welding head is transferred to the prepreg as it is, and the concave portion is transferred and remains as it is.
JP-A-61-64193 Japanese Patent Laid-Open No. 2-241091 JP 2000-294936 A

  In the present invention, when manufacturing a multilayer body used for manufacturing a multilayer printed circuit board using a conventional inner layer circuit member, a concave portion is formed in the welded portion by pressing of the welding head, and the periphery thereof becomes convex. When the laminate is heated and pressed, displacement or distortion occurs between the inner layer circuit members, and when the metal foil is laminated on the outermost layer during the heating and pressing, the outermost metal foil The present invention relates to a method for manufacturing a laminated body that can solve the problem that a concave portion is transferred.

  That is, the laminate manufacturing method of the present invention is a method of manufacturing a laminate by partially temporarily welding the laminate body by pressing the welding head from both sides of the laminate to which the inner layer circuit member and the prepreg are laminated. When the laminated body is temporarily welded by pressing the welding head to a plurality of temporary welding portions along a substantially linear shape, the width in the short direction is long between the plurality of temporary welding portions and the welding head. A metal plate having a thickness of 2 to 7 times the width of the welding head and having a thickness of 0.1 to 0.5 mm is disposed, and the stacked body is temporarily welded by the welding head with the metal plate interposed therebetween. It is characterized by this.

  According to the laminate manufacturing method of the present invention, it becomes difficult to form a concave portion in the welded portion due to the pressure of the welding head, so that the inner layer circuit members generated during the secondary lamination during the production of the multilayer circuit board Suppression and distortion can be suppressed, and even when a metal foil is laminated on the outermost layer during the heat-press molding of the secondary lamination, it is possible to inhibit the concave portion from being transferred to the outermost metal foil. .

  The method for producing a laminate of the present invention is a method for producing a laminate by partially temporarily welding the laminate body by pressing the welding head from both sides of the laminate to which the inner circuit member and the prepreg are laminated. When the laminated body is temporarily welded by pressing the welding head to a plurality of temporary welding portions along a substantially linear shape, the width of the short side direction is long between the welding head and the plurality of temporary welding portions. A metal plate having a thickness of 2 to 7 times the width of the welding head and having a thickness of 0.1 to 0.5 mm is disposed, and the laminate is temporarily welded by the welding head with the metal plate interposed therebetween. It is characterized by.

  The inner layer circuit member in the present invention is a printed circuit board substrate having a conductor layer for forming a circuit pattern on one or both sides thereof, which is also referred to as a printed wiring board substrate. Specifically, Matsushita Electric Works, Ltd. Examples thereof include R-1766 and R-1566 manufactured by the company.

  When an inner layer circuit member is used for a multilayer wiring circuit board, a circuit pattern is usually formed on the surface thereof. As the circuit pattern, a wiring circuit pattern according to the purpose is formed by using a known wiring circuit pattern forming method such as etching.

  On the other hand, a prepreg is a layered material obtained by impregnating a base material with a resin, which has been conventionally used as an insulating layer in the production of a multilayer wiring circuit board.

  Examples of the base material constituting the prepreg include inorganic fibers such as glass, synthetic resin fibers such as polyester, polyamide, polyacryl, and polyimide, or woven fabrics such as cotton, nonwoven fabrics, and paper.

  Examples of the resin constituting the prepreg include thermosetting resin compositions such as epoxy resins, phenol resins, polyimide resins, unsaturated polyester resins, polyphenylene ethers alone, modified products, mixtures, and the like. Is mentioned.

  One embodiment of the production process of the laminate in the present invention will be described below.

  First, as shown in FIG. 1, at least one inner layer circuit member 1 is overlapped with a prepreg 2 to form a stacked body 10. At this time, for example, when a circuit pattern is formed on both surfaces of the inner layer circuit member 1 and five inner layer circuit members 1 are used, a multilayer wiring circuit board having a ten-layer wiring circuit pattern is obtained. .

  As shown in FIG. 2, the inner layer circuit member 1 usually has a plurality of product parts 4 that are cut at the center and cut out as a final product, and any of the parts that are normally cut off at the outer peripheral part. A plurality of temporary welding portions 5 are provided at the position.

  Adjacent inner layer circuit member 1 and prepreg 2 are accurately stacked so that there is no positional shift in a direction parallel to the surface direction. In addition, the end portions of the inner layer circuit member 1 and the prepreg 2 are usually provided with a laminating guide hole 6, and by arranging a fixing pin so as to penetrate the laminating guide hole 6, The device 1 is devised so that a positional shift does not occur.

  The laminated body 10 shown in FIG. 1 is disposed between a pair of opposing welding heads 100 provided at the top and bottom of the welding apparatus as shown in FIG. 3 in the temporary welding step.

  Under the present circumstances, in this invention, the metal plate 7 is arrange | positioned between the welding head 100 which opposes the temporary welding part 5 of the member 1 for inner layer circuits located in the outermost layer of the laminated body 10. FIG.

  By welding with the metal plate 7 interposed, the welding head 100 does not directly press the temporary welding portion 5, and the metal plate 7 having an area larger than the area where the welding head 100 abuts is pressed. The temporary welded portion 5 is not formed in a concave shape, or even if formed, the provisional welded portion 5 becomes very gentle compared to the conventional concave shape.

  The metal plate used in the production method of the present invention is a long metal plate having a thickness of 0.1 to 0.5 mm and disposed between the plurality of temporary welding portions and the welding head.

  In addition, the long shape in this invention means the shape which covers the temporary welding part located in a line substantially linearly as shown in FIG. 4, The long axis and short axis similar to a rectangle other than a rectangle It is a concept that also includes a deformed shape having punch holes or the like provided in the inside thereof within a range that does not impair the effects of the present invention for the purpose of adjusting the thermal diffusibility.

  In addition, when the thickness of the metal plate is less than 0.1 mm, the rigidity of the metal plate is too low, and the pressure by the welding head cannot be sufficiently dispersed in the metal plate, and the temporary welding portion becomes a concave shape, When the thickness exceeds 0.5 mm, the heat required for welding the welded portion is excessively diffused by the metal plate, so that the welding force becomes insufficient.

  Although it does not specifically limit as a material of a metal plate, Specifically, metal plates, such as SUS, copper, aluminum, are mentioned, for example. Among these, SUS is preferable from the viewpoints of strength, heat resistance, and rust resistance.

  As for the size of the metal plate, the width of the long metal plate in the short direction is 2 to 7 times, preferably 2 to 5 times, the width of the welding head in the above direction. If the magnification is less than 2 times, the heat of the welding head cannot be sufficiently diffused, and since the pressing force is not sufficiently dispersed, the temporary welded portion tends to be concave, and 7 times In the case of exceeding the above range, the thermal diffusibility is too high, the welding area is widened, and there is a possibility of affecting the circuit forming portion, and the welding force may be lowered.

  In addition, as a metal plate, in order to control heat diffusivity moderately, as shown in FIG. 5, the heat insulating material which has a width | variety 2-6 times the width | variety of the transversal direction of the metal plate 7 at least in the one side of the longitudinal direction It is preferable from the point of heat insulation efficiency that 8 is connected.

  In addition, the surface of the metal plate prevents the inner circuit member and the welding head from fusing at the time of temporary welding, and maintains the releasability. The average roughness (Ra) is preferably 6.3 μm or less, the maximum height (Ry) is 25 μm or less, and the ten-point average roughness (Rz) is preferably 25 μm or less.

  The metal plate to which the heat insulating material is connected is obtained by connecting the heat insulating material to the metal plate by a heat-resistant tape, a heat-resistant adhesive or the like, or a connection by welding.

  As a material of the heat insulating material, a heat insulating plate formed from an organic heat insulating material, an inorganic heat insulating material, an organic inorganic composite heat insulating material having a thermal conductivity of 0.5 W / mK or less, specifically, for example, Nikko Kasei Co., Ltd. ) Product name Rosna board etc. is used.

  As a method for temporarily welding the laminated body, the laminated body 10 is arranged in a known welding apparatus as shown in FIG. 3, and the temporary welding portion 5 and the lowermost layer of the inner circuit member 1 located in the uppermost layer in the drawing. A plurality of welding heads 100 are arranged so as to face the temporary welding portion 5 of the inner layer circuit member 1 positioned at the upper and lower sides, and a metal plate 7 is interposed between the welding head 100 and the innermost layer circuit member 1. The temporary welding part 5 of the inner layer circuit member 1 is heated while being pressed through the metal plate 7.

  At this time, means for arranging the metal plate 7 on the laminated body is not specifically limited, but examples include the following means.

  When the temporary welding is performed, a stacked body pressing plate is provided for adjusting the thickness by temporarily pressing a portion other than the welding margin of the stacked body after placing the stacked body on the table of the welding apparatus. However, the metal plate is connected to a means for connecting the metal plate to the laminate pressing plate, a cylinder interlocked with the ascending / descending cylinder of the welding head of the welding apparatus, and the welding head and the temporary welding portion at the time of temporary welding. Means such as disposing a metal plate so as to be interlocked with the operation of the welding head in between.

  And the laminated body for using for heat-pressure molding can be formed by hardening the part of the prepreg 2 pinched by the welding head 100 which opposes, and temporarily fixing the adjacent inner layer circuit member 1.

  Examples of the welding head 100 include those that apply ultrasonic waves to a prepreg by ultrasonic vibration welding and heat them, and those that heat by an electric heater.

  The heating condition is not particularly limited as long as temporary welding can be performed, and is selected according to the type of prepreg, but is usually about 170 to 300 ° C., more preferably about 250 to 300 ° C., for 10 to 120 seconds, and further 20 to 20 ° C. 60 seconds is preferable. Moreover, when applying ultrasonic vibration, it is preferable that the frequency shall be 10-50 kHz, and pressurization and ultrasonic vibration application time shall be 10-120 seconds. Further, the pressure applied by the heater jig at the time of temporary welding is not particularly limited as long as the temporary welding can be performed. For example, when an epoxy resin thermosetting resin composition is used as a prepreg, the pressure is usually 0.4. About 1 MPa.

  Next, a method for forming a multilayer wiring circuit board using the laminate obtained by the present invention will be specifically described.

  First, as shown in FIG. 6, a laminated body 11 temporarily welded by a temporary welding portion 5 between a pair of pressure plates 20 and 21 of a hot press, and a prepreg 9 are arranged on both surfaces thereof, and a metal foil 3 is further laminated. Let

  A laminate 11 (hereinafter also referred to as a foil laminate 12) on which the metal foil 3 is laminated is subjected to heat and pressure molding. That is, the inner layer circuit member 1 of the laminated body 11 and the adjacent prepreg 2 are welded as a whole, and the prepreg 9 and the metal foil 3 adjacent to the prepreg 9 are welded and hardened as a whole to be integrated. A printed circuit board is formed.

  In addition, it is preferable that the foil laminated body 12 is pressure-reduced before heat-press molding. This is because gas such as air in the foil laminate 12 remains in the multilayer printed circuit board until after the heat and pressure molding, and the generation of voids is suppressed.

  The foil laminate 12 that has been subjected to the reduced pressure treatment is then heated and pressurized.

  Conditions for heating and pressing are not particularly limited, and conditions for forming a normal multilayer wiring circuit board can be employed. Specifically, conditions of heating temperature of 170 to 200 ° C., pressurization pressure of 2 to 4.9 MPa, and heating time of 150 to 200 minutes are selected. Further, the heating / pressurizing conditions may be programmed and performed under multistage conditions.

  In the heat and pressure molding process, when a laminate obtained by a conventional manufacturing method is used, a concave portion generated at the time of the temporary welding or a convex portion formed around the metal foil of the outermost layer is provided. Although there was a problem of being transferred, when the laminate obtained by the production method of the present invention is used, the above problem can be solved.

  In addition, the heating and pressing is usually performed by heating and pressing at the same time by stacking a plurality of sets of multilayer wiring circuit boards, usually about 10 to 20 sets via a metal separator, in order to improve productivity. Is done. At this time, if a concave portion or a convex portion is generated in the outermost layer of each laminated body, since the laminated body is inclined or distorted as a whole, it cannot be heated and pressurized uniformly and obtained. In some cases, the thickness of the multilayer printed circuit board, the adhesive strength of each layer, and the dimensional accuracy are not uniform.

  In the case of manufacturing a multilayer wiring circuit board using the laminate obtained by using the manufacturing method of the present invention, the inclination can be suppressed, and even when a plurality of sets of multilayer wiring circuit boards are manufactured at the same time, it is uniform. A multilayer wiring circuit board can be obtained.

  Hereinafter, the method for producing a multilayer printed circuit board according to the present invention will be described in more detail with reference to examples. This example is only an example of an embodiment of the present invention.

In this example, the raw materials used are shown below.
Prepreg: “R-1661GG 0.1t” manufactured by Matsushita Electric Works, Ltd. (FR-4 prepreg, size 510 × 610 (mm), thickness 0.1 mm, resin content 52%)
Inner layer circuit member: Double-sided copper-clad laminate (“R-1766” manufactured by Matsushita Electric Works Co., Ltd., FR-4 core, size 510 × 610 (mm), thickness 0.1 mm, copper foil thickness 35 μm)
Metal foil: size 510 × 610 (mm), 12 μm thick copper foil metal plate: SUS length 630 mm rectangular metal plate with the width and thickness shown in Table 1 and heat-insulating metal plate: SUS length A heat insulating plate having a width of 10 mm and a thickness of 10 mm with respect to the width in the short direction of the metal plate on both sides in the longitudinal direction of a rectangular metal plate having a width and thickness of 630 mm and a width and thickness described in Table 1 Metal plate with heat insulating material fixed with heat insulating tape so as to be thermally continuous.

<Examples 1-8>
The inner layer circuit members 41 and 44 and the prepregs 42 and 43 are superposed in the layer configuration shown in FIG. 8 using the inner layer circuit member having a shape as shown in FIG. 7 having circuit patterns formed on both surfaces. A metal plate having the shape shown in Table 1 between the welding head 100 and the temporary welding portion 5 of the ultrasonic vibration heating apparatus (welding head contact surface dimension (4 × 20 (mm))) as shown in FIG. 7 through.

  Next, the welding head 100 was made to contact and press the temporary welding part 5 via a metal plate, and the temporary welding was performed in the temporary welding part 5, and the laminated body was obtained. In the temporary welding step at this time, the welding head 100 was brought into contact with the temporary welding portions at the surface end portions of the outermost inner layer circuit members 41 and 44 at a pressure of 6 KPa and heated at a welding set temperature of 300 ° C. for 30 seconds.

  Then, a prepreg is stacked on both surfaces of the obtained laminate, and a metal foil is stacked on the outside of the prepreg is placed between a pair of pressure plates of a heating press, and heated and pressed to obtain a thickness. A 1.0 mm multilayer printed circuit board was manufactured.

  The heating and pressing conditions were a pressure plate temperature of 180 ° C., a pressure of 2.9 MPa, and a pressing time of 180 minutes.

Evaluation of the obtained laminated body and multilayer wiring circuit board was evaluated as follows.
(Number of convex portions generated): Observe the appearance of the 20 multilayer printed circuit boards,
The number of wrinkles (convex parts) generated on the metal foil was counted.
(Magnification of welding area): Area of the temporarily welded portion with respect to the area of the welding head (80 mm ² )
Was measured and calculated.
(Welding force): Out of the six temporary welding portions 5 of the obtained laminate, one central temporary welding portion
Leave the welded state of only the welded part 5 and the welded state of the other welded parts 5
Solved.
And a 1 × 5 (cm) strip-shaped inner layer circuit as shown in FIG.
Processed into a test piece in a form in which two members are temporarily welded at the center,
Hold both ends of the processed specimen with opposite chucks of the tensile tester
The tensile shear strength was measured.

The results are shown in Table 1.

<Comparative example 1>
It implemented like Example 1 except not using a metal plate. The evaluation results are shown in Table 2.
<Comparative Examples 2-5>
It implemented like Example 1 except having used the metal plate of Table 1. The evaluation results are shown in Table 2.

  From the results of Tables 1 and 2, in Examples 1 to 8 using the production method of the present invention, the resulting multilayer wiring circuit board was free from wrinkles on the metal foil on the surface. On the other hand, the multilayer wiring obtained in Comparative Example 1 in which the metal plate was not used, Comparative Example 2 in which the metal plate was used but the thickness was thin 0.05 mm, and Comparative Example 3 in which the width of the metal plate was the same width as the welding head On the circuit board, wrinkles were frequently observed on the metal foil on the surface.

  In the case of Comparative Example 4 in which the width of the metal plate is too wide, in the case of Comparative Example 5 in which the thermal diffusivity is too high, the welding area is too wide and the welding force is insufficient, and the thickness of the metal plate is too thick. However, the heat of welding heat was poor and the welding power was insufficient.

  On the other hand, the Example using a heat insulating material has high welding power, and when comparing Example 3 and Example 8 in which the shape of the metal plate is equivalent, the heat conductivity of the heat insulating material is less than 0.6 W / mK. The welding power of Example 3 was higher.

It is sectional drawing of an example of the laminated structure of a laminated body. It is a top view which shows an example of the form of the member for inner layer circuits. It is sectional drawing which shows an example of a temporary welding process. It is a top view which shows an example which has arrange | positioned the metal plate in the temporary welding part of the member for inner layer circuits of the outermost layer of a laminated body. It is a top view which shows an example of the form of the metal plate in this invention. It is sectional drawing of an example of the heating-pressing process in this invention. It is a top view which shows the arrangement pattern and dimension of the circuit pattern part and temporary welding part of the member for inner layer circuits in an Example. It is a schematic cross section which shows the layer structure of the laminated body in an Example. It is a schematic diagram which shows the test piece used for the welding power evaluation test in an Example, Fig.9 (a) is the top view, FIG.9 (b) is the sectional drawing. It is the top view and sectional drawing which show the form of the temporary welding part of the conventional laminated body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 41, 44 Inner layer circuit member 2, 9, 42, 43 Prepreg 3 Metal foil 4 Circuit pattern part 5 Temporary welding part 6 Lamination guide hole 7 Metal plate 8 Heat insulating material 10 Laminated body 11 Laminated body 12 Foil laminated body 20, 21 Pressure plate 15 Foil laminate 100 Welding head

Claims (3)

It is a method of manufacturing a laminate by partially temporarily welding by pressing a welding head from both sides of a laminate to which an inner layer circuit member and a prepreg are laminated,
When the welded body is temporarily welded by pressing a welding head against a plurality of temporarily welded portions along a substantially straight line, the width between the plurality of temporarily welded portions and the weld head is short and short. there is disposed a metallic plate of the wider area than the welding head is in contact such that the thickness is 2 to 7 times 0.1-0.5 m m in the short direction of the width of the welding head, A method for manufacturing a laminated body, wherein the laminated body is temporarily welded by a welding head with the metal plate interposed therebetween.   The manufacturing method of the laminated body of Claim 1 with which the heat insulating material which has a width | variety 2-6 times the width | variety of the transversal direction of the said metal plate is connected to at least one side of the said metal plate at the longitudinal direction.   The manufacturing method of the laminated body of Claim 1 or Claim 2 whose said heat insulating material is a heat insulating material with a heat conductivity of 0.5 W / mK or less.

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