JPH04326597A - Manufacture of multilayer printed wiring board - Google Patents

Abstract

PURPOSE:To prevent relative positional displacement during the lamination process in which a plurality of two-sided printed wiring boards are contact- laminated by pressing under heat. CONSTITUTION:Printed wiring boards are positioned by means of a fixing pin 11 provided on a stainless plate 10 together with a float pin 12. A plurality of two-sided printed wiring boards 16 are securely held, via a circular hole 6 thereof, by means of the float pin 12. Along hole 7 is drilled at the position of copper foils 4 and prepregs 15 into which the float pin 12 is inserted, as well as at the position of the two-sided printed circuit boards 16, the copper foils 14, and the prepregs 15 into which the fixing pin 11 is inserted. The long hole 7 is in such a configuration that the plane cross section of the float pin 12 and fixing pin 11 is extended toward the conic axis passing through the center of the multilayer printed circuit board. A connection 8 of the float pin 12 is movable inside a groove 9 of the stainless plate 10 toward a comic axis 5.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a multilayer printed wiring board, and more particularly to a method for manufacturing a multilayer printed wiring board in which a plurality of printed wiring boards are bonded under heat and pressure via prepreg to form multiple layers.

0002

[Prior Art] Conventionally, positioning of a multilayer printed wiring board in which a plurality of printed wiring boards are heat-pressed and bonded via prepreg to create a multilayer structure is as follows: (1) Multiple printed wiring boards, prepreg, and heat-pressed bonding A plurality of alignment holes are provided in the part of one of the pair of plates used for the process that will be in the same plane position after heat-pressing.
A column-shaped dowel pin whose flat cross section is the same shape as the dowel hole is fixed perpendicular to the plate surface on the other plate of the pair of plates used for heat crimping, in the same plane position as the dowel hole, and multiple printed wirings are fixed perpendicularly to the plate surface. A method of temporarily fixing the board and prepreg by inserting dowel pins into the matching holes and then heat-pressing them.

(2) A dowel hole having a long hole expanded in the axial direction connecting the center of the printed wiring board and the center of the dowel hole is provided in the planar cross-sectional shape of the dowel pin in a plurality of printed wiring boards and prepregs, Similar to item (1), a method of heat-pressing is performed by sandwiching a plate with a dowel pin fixed thereon and a plate with holes provided at positions corresponding to the dowel pins.

(3) After multiple printed wiring boards and prepregs are bonded by heat and pressure, a plurality of dowel holes are provided in the same plane position, and the eyelets are passed through the dowel holes and temporarily fixed.
A method of placing two plates on the outside and applying heat and pressure.

[0005] etc. are being carried out.

[0006]

[Problems to be Solved by the Invention] The above-mentioned conventional positioning methods during hot press bonding each have the following problems.

(1) Since the dimensional change due to thermal expansion of the printed wiring board during hot press bonding is larger than the dimensional change due to thermal expansion of the plate, the alignment holes may be destroyed and wrinkles or distortions may occur inside the printed wiring board. Further, since the multilayer printed wiring board usually contracts after being heat-pressed, the dowel pins are deformed. In anticipation of this shrinkage, the position of the dowel hole in the printed wiring board should be shifted outward along the axis connecting the center of the dowel hole and the center of the printed wiring board, or the position of the dowel pin should be changed in advance. Deformation of the dowel pins can be prevented by correcting the dowel pins by shifting them inward along the axis, but relatively thick printed wiring boards may bend when temporarily fixing the printed wiring board to the plate. Thin printed wiring boards wrinkle, resulting in problems such as poor interlayer adhesion, internal distortion, and destruction of the mating holes after heat-press bonding.

(2) This is an alignment method that improves the drawbacks of item (1), but for each alignment hole, the movement of the alignment pin in the axial direction connecting the center of the printed wiring board and the center of the alignment hole is controlled by, for example, Since the dowel hole on the axis orthogonal to this axis is regulated by the position of the dowel pin, a large stress is applied to the dowel hole on the orthogonal axis in the direction perpendicular to the axis toward the center. As a result, the dowel pins do not necessarily move along the dowel holes as intended, which tends to result in deformation of the dowel holes and a shift in the planar positional relationship between the printed wiring boards.

(3) This is an alignment method that improves the shortcomings in item (1), but the method of temporarily fixing the printed wiring board and prepreg with the eyelets requires that the eyelets be kept perpendicular to the printed wiring board. It has the disadvantage that it is difficult to press and easily tilts during crimping. As a result, the printed wiring boards are misaligned with each other.

The purpose of the present invention is to prevent poor interlayer adhesion, internal strain,
It is an object of the present invention to provide a method for manufacturing a multilayer printed board without problems such as destruction of alignment holes and with no misalignment of printed wiring boards.

[0011]

[Means for Solving the Problems] The present invention forms conductive circuits on either both sides or one side, and electrically connects the conductive circuits formed on both sides with plated through holes as necessary. A plurality of printed wiring boards, one of which is two copper foils and two single-sided copper foil-clad insulating boards, are placed on the outside of the board, sandwiched between a pair of plates via prepreg, and bonded by heat and pressure. A method for manufacturing a multilayer printed wiring board including a step of forming conductive circuits and plated through holes in the multilayered copper foil, comprising: a plurality of columnar fixing pins to which the pair of plates are fixed; and the plurality of printed wirings. A plate having two types of pins, a float pin and a float pin set up on a plurality of seats connecting the plates, and a fixing pin alignment hole for inserting the fixing pin having the same shape as the planar cross-sectional shape of the fixing pin, and inserting the float pin. The float pin alignment hole is formed by a plate having a widened elongated hole so that the float pin can move on an axis connecting the center of the printed wiring board and the center of the float pin.

0012

Embodiments Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view of a main part explaining a first embodiment of the present invention, FIG. 2 is a sectional view of FIG. 1, and FIG. FIG. 5 is a plan view showing an example of the arrangement of float pinning holes, and FIG. 5 is a characteristic diagram illustrating dimensional changes during the heating and cooling process of the double-sided printed wiring board and stainless steel plate during heat-pressing bonding according to the first embodiment of the present invention. .

In the first embodiment, as shown in FIGS. 1 and 2, a stainless steel plate 10 with a diameter of 5 mm and a height of 10 mm is placed at four locations around the periphery of a stainless steel plate 10 having a size of 500 mm square and a thickness of 10 mm.
A cylindrical stainless steel fixing pin 11 is fixed vertically,
Furthermore, the depth is 5mm, and the size is 21mm long axis x 15mm short axis.
Elongated hole-shaped grooves 9 are formed at four locations around the periphery.
A cylindrical stainless steel pin with a height of 10 mm and a diameter of 15 mm.
The seat 8 of the float pin 12, to which a disc-shaped stainless steel seat 8 with a thickness of 4.9 mm is attached, is inserted into the groove 9 and made to stand upright. Here, as shown in FIG. 3, the fixed pinning hole 2 and the float pinning hole 3 are located around the multilayer printed wiring board 1, and the center 4 of the multilayer printed wiring board 1 and the center of the float pinning hole 3 are located at the periphery of the multilayer printed wiring board 1. Four pieces are arranged so that the connecting radiation axes 5 are perpendicular to each other.

Further, the groove 9 for the float pin 12 of the stainless steel plate 10 is formed so that its longitudinal side coincides with the direction of the radial axis 5, and the seat 8 of the float pin 12 is formed in the groove 9 in the direction of the radial axis 5 by 3 mm on each side. Make it possible to move.

Next, 18 μm thick copper foil 14 with one side roughened is placed on both outsides, and 0.1 mm thick prepreg 15 is prepared by impregnating glass cloth with epoxy resin and drying it to a semi-hardened state. Three double-sided printed wiring boards with a thickness of 0.1 mm, each having a conductive circuit 18 formed on both sides of an epoxy insulator 17 supported by glass cloth, are stacked and placed on the stainless steel plate 10, and then the stainless steel plate 1
3 and sandwiched between a pair of stainless steel plates 10 and 13. Here, the fixing pin 11 and the float pin 12 of the copper foil 14 and the prepreg 15 are formed in advance by forming a long hole 7 with a length of 11 mm in major diameter x 5 mm in minor diameter so that the longitudinal direction of the hole 7 is in the direction of the radial axis 5 and the centers are aligned. do.

Furthermore, since it is known from FIG. 5 that the dimensions of the double-sided printed wiring board 16 shrink by 0.02% due to heat-pressure bonding, the conductive circuit 18 is preliminarily expanded so that the pattern is expanded by 0.02% compared to the actual size. Correct the pattern. A long hole 7 with a long diameter of 11 mm x a short diameter of 5 mm is formed in the fixing pin 11 portion of the double-sided printed wiring board 16 using copper foil 14.
, and prepreg 15, and a circular hole 6 with the same diameter of 5 mm into which the float pin 12 is inserted is provided in the float pin 12 portion. The fixing pin 11 part of the stainless steel plate 13 has a circular hole 6 with the same diameter of 5 mm into which the fixing pin 11 is inserted.
, and the length of the float pin 12 is 11 mm.
x Provide a long hole 7 with a short diameter of 5 mm.

As a result, in the elongated hole 7, the fixed pin 11 and the float pin 12 are spaced 3 m on each side in the direction of the radial axis 5.
It becomes possible to move in steps of m, and the movement in the circular hole 6 is restricted by the float pin 12.

Next, these were subjected to a pressure of 25 kg/cm2,
After heating and pressing at a temperature of 170°C for 60 minutes and making a through hole, electrolytic copper plating is applied to the entire surface to form a plated through hole, and predetermined areas of the copper plated copper foil 14 are etched away to form a conductive circuit. A multilayer printed wiring board was obtained.

FIG. 4 is a plan view showing another example of the arrangement of the fixed pinning holes and the float pinning holes to explain the first embodiment of the present invention.

Another arrangement example of the fixed pin alignment holes and the float pin alignment holes to explain the first embodiment is as shown in FIG.
1 and 2 except that it is formed on the peripheral diagonal of
Alignment was performed in exactly the same manner as in Example 1, and a multilayer printed wiring board was manufactured in exactly the same manner.

FIG. 6 is a plan view of a main part explaining a second embodiment of the present invention, FIG. 7 is a sectional view of FIG. 6, and FIG. FIG. 3 is a plan view showing an example of the arrangement of float pinning holes.

In the second embodiment, as shown in FIGS. 6 and 7, a stainless steel plate 10 with a diameter of 5 mm and a height of 10 mm is placed at four locations around the periphery of a stainless steel plate 10 having a size of 500 mm square and a thickness of 10 mm.
A cylindrical stainless steel fixing pin 11 is fixed vertically,
Furthermore, long hole-shaped grooves 9 with a depth of 5 mm and a length of 27 mm in length and a width of 41 mm in width were formed at four locations around the periphery, and three cylindrical stainless steel pins with a diameter of 5 mm and a height of 10 mm were placed in a 27 mm long hole.
The seat 8 of the float pin 12 attached to the stainless steel seat 8 of m×35 mm and thickness 4.9 mm is inserted into the groove 9 and made to stand upright. Here, as shown in FIG. 8, the fixed pinning hole 2 and the float pinning hole 3 are located around the multilayer printed wiring board 1, and the center 4 of the multilayer printed wiring board 1 and the center of the float pinning hole 3 are located at the periphery of the multilayer printed wiring board 1. The connecting radiation axes 5 are arranged at four locations so that adjacent ones are perpendicular to each other.

Furthermore, the groove 9 for the float pin 12 in the stainless steel plate 10 is formed so that its longitudinal side is in the direction of the radial axis 5, and the seat 8 of the float pin 12 is moved within the groove 9 in the direction of the radial axis 5 by 3 mm on each side. It can be so.

Next, 18 μm thick copper foil 14 with one side roughened is placed on both outsides, and 0.1 mm thick prepreg 15 is prepared by impregnating glass cloth with epoxy resin and drying it to a semi-hardened state. Three double-sided printed wiring boards with a thickness of 0.1 mm on which conductive circuits 18 are formed on both sides of an epoxy insulator 17 supported by glass cloth are placed on the stainless steel plate 10, and then a pair of stainless steel plates 13 are placed on top of the stainless steel plate 10. The laminate is sandwiched between stainless steel plates 10 and 13. Here, the fixing pin 11 of the copper foil 14 and the prepreg 15 is
and the position of the float pin 12 has a size of 1 in advance.
A long hole 7 with a diameter of 1 mm x a short diameter of 5 mm is formed with the longitudinal direction being the direction of the radiation axis 5 and the centers thereof being aligned.

Furthermore, since it is known from FIG. 5 that the double-sided printed wiring board 16 shrinks by 0.02% due to heat and pressure bonding, the conductive circuit 18 is preliminarily expanded so that the pattern is expanded by 0.02% compared to the actual size. Correct the pattern. In the fixing pin 11 portion of the double-sided printed wiring board 16, a long hole 7 with a length of 11 mm x 5 mm in width is provided in the same way as the copper foil 14 and the prepreg 15, and in the float pin 12 portion, a hole 7 with the same diameter of 5 mm into which the float pin 12 is inserted is provided. A circular hole 6 was provided. The fixing pin 11 portion of the stainless steel plate 13 is provided with a circular hole 6 having the same diameter of 5 mm into which the fixing pin 11 is inserted, and the float pin 12 portion is provided with an elongated hole 7 having a length of 11 mm in length and a short diameter of 5 mm.

As a result, in the elongated hole 7, the fixed pin 11 and the float pin 12 are separated by 3 mm on each side in the direction of the radial axis 5.
In addition, the movement in the circular hole 6 is regulated by the float pin 12.

Next, these were subjected to a pressure of 25 kg/cm2,
After heating and pressing at a temperature of 170°C for 60 minutes and making a through hole, electrolytic copper plating is applied to the entire surface to form a plated through hole, and predetermined areas of the copper plated copper foil 14 are etched away to form a conductive circuit. A multilayer printed wiring board was obtained.

FIG. 9 is a plan view showing another example of the arrangement of the fixed pinning holes and the float pinning holes to explain the second embodiment of the present invention.

Another arrangement example of the fixed pinning holes and the float pinning holes to explain the second embodiment is to place the float pinning holes 3 on a diagonal line around the periphery of the multilayer printed wiring board 1, as shown in FIG. Except for the formation, positioning was carried out in exactly the same manner as in the second embodiment shown in FIGS. 6 and 7, and a multilayer printed wiring board was manufactured using the same method.

[0031]

Effects of the Invention As explained above, the present invention uses the fixing pin 11 and the float pin 12 attached to the stainless steel plate 10 for positioning, thereby reducing the positional deviation between the internal conductive circuits that occurs during heat compression bonding. The dimensional expansion/contraction of the double-sided printed wiring board after heat-press bonding was ±0.005% or less with respect to the expected value. In addition, no deformation of the pin, deformation or destruction of the dowel hole, etc., which occurs when fixing the pin to a stainless steel plate, was observed.

As described above, the present invention has the effect of significantly improving the misalignment between internal conductive circuits that occurs when multilayering is carried out by thermocompression bonding.

[Brief explanation of the drawing]

FIG. 1 is a plan view of essential parts for explaining a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of FIG. 1;

FIG. 3 is a plan view showing an example of the arrangement of fixed pinning holes and float pinning holes, explaining the first embodiment of the present invention.

FIG. 4 is a plan view showing another example of the arrangement of fixed pinning holes and float pinning holes to explain the first embodiment of the present invention.

FIG. 5 is a characteristic diagram illustrating dimensional changes in the heating and cooling process of the double-sided printed wiring board and stainless steel plate during heat-press bonding in the first embodiment of the present invention.

FIG. 6 is a plan view of essential parts for explaining a second embodiment of the present invention.

FIG. 7 is a cross-sectional view of FIG. 6;

FIG. 8 is a plan view showing an example of the arrangement of fixed pinning holes and float pinning holes, explaining a second embodiment of the present invention.

FIG. 9 is a plan view showing another example of a fixed pinning hole and a float pinning hole to explain the second embodiment of the present invention.

[Explanation of symbols]

1 Multilayer printed wiring board 2 Fixed pin alignment hole 3 Float pin alignment hole 4 Center 5 Radial axis 6 Circular hole 7 Elongated hole 8 Seat 9 Groove 10, 13 Stainless steel plate 11 Fixed pin 12 Float pin 14 Copper foil 15 Prepreg 16 Double-sided printed wiring Plate 17 Insulator 18 Conductive circuit

Claims (2)

[Claims] 1. A plurality of printed wiring boards each having conductive circuits formed on either both sides or one side, and electrically connecting the conductive circuits formed on both sides with plated through holes as necessary. Either one of a sheet of copper foil and two single-sided copper foil-clad insulating boards is placed on both outer sides, sandwiched between a pair of plates with a prepreg interposed therebetween, and multi-layered by heat and pressure bonding. In a method for manufacturing a multilayer printed wiring board, the method includes forming conductive circuits and plated through holes in a plurality of seats connecting a plurality of columnar fixing pins to which the pair of plates are fixed and a plurality of seats connecting the plurality of printed wiring boards. A plate having two types of pins, including an erected float pin, and a fixed pin alignment hole for inserting the fixed pin having the same shape as the flat cross-sectional shape of the fixed pin, and a float pin alignment hole for inserting the float pin having the same shape as the flat cross-sectional shape of the fixed pin. 1. A method for manufacturing a multilayer printed wiring board, characterized in that the plate is formed with a plate having a widened elongated hole so that the float pin can move on an axis connecting the center of the printed wiring board and the center of the float pin. 2. The method of manufacturing a multilayer printed wiring board according to claim 1, wherein at least three of the float pins are installed in a common seat at each location.