JPH0451080B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for manufacturing a multilayer printed wiring board, in which holes are formed at predetermined positions with high accuracy in a multilayer printed wiring board drilling process. (Prior art) In a conventional method for manufacturing a multilayer board, the base materials for each layer forming the outer and inner layers of the multilayer board are alternately stacked with prepreg using a lamination reference pin between lamination molds made of stainless steel plates, etc. The multilayer substrates are stacked together and heated and pressurized using a lamination press to form a laminate, and then the laminate mold and the laminate reference pin are removed from the multilayer substrate. Thereafter, in the drilling process, a drilling reference pin was reattached to the reference pin hole used in the lamination process, and drilling was performed using this as a reference. However, with this method, there is a step of first removing the reference pin for lamination and then reattaching the reference pin for drilling, which may cause wobbling in the reference pin hole, or heat shrinkage due to layer formation when removed from the lamination mold. This resulted in the inability to drill holes accurately at predetermined positions. To address these problems, there has been a method for using the lamination reference pin as it is as a drilling reference pin, but this method cannot cope with dimensional changes due to thermal contraction of the entire multilayer board. For the latter, there were methods of correcting the hole position coordinates according to the thermal contraction of the multilayer board, or methods of forcibly pulling the multilayer board to make it to the specified dimensions, but depending on the prepreg material, Heat shrinkage is completely different, and the degree of heat hardening also differs depending on the position within the lamination press, making it difficult to correct hole position coordinates due to variations in heat shrinkage.
Furthermore, the device for pulling the multilayer substrate is mechanically complex. (Problems to be Solved by the Invention) The present invention has been made in view of the above-mentioned circumstances, and the problems to be solved by the present invention are as follows: This is due to insufficient hole position accuracy. It is an object of the present invention to manufacture a multilayer printed wiring board that can accurately drill holes at predetermined positions without adding complicated processes or mechanisms in the hole punching process after layer formation. The purpose is to provide a method. (Means for Solving the Problems) The means taken by the present invention to solve the above problems are as follows: ``The multilayer board components are laminated and fixed between a set of laminated molds using reference pins, and heated. After pressing to form a multilayer board, in the step of drilling holes, a disposable board for drilling is interposed between the multilayer board components and the lower laminated mold, the stack is fixed, and the multilayer board is formed by heating and pressing. After that, only the upper laminated mold is removed and a hole is made, and then the lower laminated mold, the disposable plate for drilling, and the reference pin are removed from the multilayer board. ``Manufacturing method.'' Next, the present invention will be explained in more detail with reference to FIGS. 1 and 2, which correspond to embodiments thereof. The upper laminated mold 4 is made of a material with excellent heat resistance and is thick enough to withstand considerable external stress.
and a lower lamination mold 1, a lamination reference pin 3 made of a material that can withstand considerable external stress, and a multilayer board made of a material that can withstand pressure and heat during lamination and has excellent machinability. A disposable board 5 for drilling with the same area is prepared, for example, a plastic plate such as heat-resistant epoxy or polyimide, or a composite material containing the same, or a metal plate such as copper or aluminum. Note that this hole-drilling waste plate 5 is used to prevent the hole from being exposed in the lower laminated mold 1 during hole-drilling, and usually needs to have a thickness of about 1.5 mm. Then, the lamination reference pin hole 2 of the lower lamination mold 1
Set up a reference pin 3 for lamination, and use a disposable board 5 for drilling, which has a hole at the same position as the reference pin hole 2 and a hole slightly larger than the reference pin hole 2.
put on. Further, the base materials 7 for each layer forming the outer layer and the inner layer and the adhesive prepreg 8 are piled up using the lamination reference pin 3 as a reference. At this time, if a release paper 6 is placed on top of the hole punching board 5 and on the top of the stacked base materials 7, the resin of the multilayer substrate will not adhere to other substrates during lamination. Finally, the upper lamination mold 4 is placed and heated and pressed using a lamination press to form a multilayer substrate. After the lamination was formed, only the upper lamination mold 4 and the upper release paper 6 were removed, and the lower lamination mold 1, the punching waste plate 5, and the lamination reference pin 3 were attached to the sub-table 11 of the numerically controlled drilling machine. The multilayer board as it is is set, and a hole punching plate 9 made of aluminum or phenol resin is applied to prevent burrs, and holes are drilled. Thereafter, the lamination reference pin 3, the lower lamination mold 1, the hole punching plate 9, and the hole punching waste plate 5 are removed from the multilayer board 14, and a multilayer board with holes in the desired positions is obtained. . (Actions of the Invention) By adopting the above-described measures, the present invention has the following effects. According to the present invention, since the lower lamination mold 1 and the lamination reference pin 3, which have excellent heat resistance and can withstand considerable external stress, are not removed from the multilayer substrate after the lamination is formed, dimensional changes due to thermal contraction of the multilayer substrate occur. is the same as the laminated mold, and the dimensional change is very small compared to when the laminated mold is removed. As a result, the inner layer pattern is at the same position as the design value, and there is almost no deviation from the design hole position coordinates. Therefore, it becomes possible to drill holes at desired positions with high precision. That is, in the present invention, when heat-pressing each layered board using a laminating press machine, a hole-drilling sacrificial plate 5 is interposed between the multilayered board component and the lower laminated mold, and both laminated molds 1 and Since the heating is carried out in 4 hours, not only each layer substrate itself but also the hole-drilling pad 9, the hole-drilling waste plate 5, and each lamination reference pin 3 are heated. Therefore, even if the dimensions of each member change,
Each multilayer board remains held in the lamination mold by each lamination reference pin 3, and after cooling, it becomes the size of the lower lamination mold, preventing thermal shrinkage, and there is no dimensional variation between each multilayer board. It has become a thing. Then, the lower lamination mold 1 and the lamination reference pin 3
Since the hole is drilled without removing it from the multilayer substrate, it is possible to drill the hole without having to correct the coordinates of the hole position at all. Therefore, when a hole is made by the manufacturing method of the present invention, the hole is formed at a desired position based on each layer. Next, the present invention will be explained with reference to examples. (Example) Example 1 A carbide mold with a diameter of 5 mm and a length of 11 mm is placed in a lower lamination mold 1 made of SUS304 of 330 mm x 500 mm and a thickness of 5 mm. Set up an alloy lamination reference pin 3, assemble a 1.5 mm thick heat-resistant glass epoxy drilling board 5, and then place a release paper (trade name: Tedlar) 6 on top of it.
Four sheets of glass epoxy base material 7 of 330 mm x 500 mm and 0.2 mm thickness and six sheets of adhesive prepreg 8 of 0.1 mm thickness are stacked alternately, and release paper (trade name: Tedlar) 6 is placed on top, and finally An upper laminated mold 4 having the same material and shape as the lower laminated mold 1 was mounted. Then, in a lamination press machine, the pressure was 40Kg/cm ² ,
Raise the temperature to 170℃ at a heating rate of 5℃/min.
Maintain the state for 80 minutes, heat and pressurize, and reduce the temperature to 5.
It was cooled to room temperature at a rate of °C/min to form an 8-layer substrate with a thickness of 1.6 mm. Then, the upper lamination mold 4 and the upper release paper 6 are removed, set on the sub-table 11 of the numerically controlled hole punching machine, a 0.15 mm thick aluminum hole punching plate 9 is placed, the holes are punched, and the sheets are laminated. The reference pin 3, the lower laminated mold 1, the hole punching plate 9, the hole punching waste plate 5, and the lower release paper 6 are removed from the multilayer substrate 14, and the holes are precisely drilled at the desired positions 8.
A layered substrate was obtained. In contrast to the above method, the deviations between the inner layer pattern and the holes were as shown in Table 1.

[Table] Example 2 A cemented carbide laminate with a diameter of 5 mm and a length of 13 mm is placed on a lower laminate mold 1 made of SUS304 of 330 mm x 500 mm and 6 mm thick, in which 10 reference pin holes 2 for lamination with a diameter of 5 mm are arranged. 330mm x 500mm, with a 5.5mm diameter hole in the same position as the lamination reference pin hole 2.
A disposable board 5 for drilling holes made of glass polyimide with a thickness of 1.5 mm was placed on it. Next, put release paper 6 on it, 330mm x
Seven glass polyimide outer layer and inner layer substrates 7 of 500 mm and 0.2 mm thick, and 12 sheets of adhesive prepreg 8 of 0.1 mm thick were stacked alternately, and a release paper 6 was placed on them.
Upper laminated mold 4 of the same material and shape as the lower laminated mold
I carried it. Thereafter, a 14-layer substrate with a thickness of 2.6 mm was obtained by heating and pressing using a laminating press. Then, remove the upper lamination mold 4 and the release paper 6, set it on the sub-table 11 of the numerically controlled hole punching machine, place the 0.15 mm thick aluminum hole punching plate 9, and drill the hole. Reference pin 3,
The lower laminated mold 1, the hole punching plate 9, the hole punching waste plate 5, and the lower release paper 6 were removed from the multilayer substrate 14, and a 14-layer substrate in which holes were accurately punched at desired positions was obtained. . In contrast to the above method, the deviations between the inner layer pattern and the holes were as shown in Table 1. Comparative Example 1 Using a set of lamination molds and lamination reference pins, base materials forming the outer layer and inner layer and adhesive prepregs were stacked alternately, heated and pressurized to form a laminate, and then the lamination mold and lamination reference pins were used. Remove the pin from the multilayer board, reinstall the reference pin for drilling into the reference pin hole for lamination, set the multilayer board on the sub-table 11 of the numerically controlled drilling machine, and drill the hole at the same position as the designed hole position. did. Comparative Example 2 The multilayer board formed by the same method as Comparative Example 1 was set as it was on the sub-table 11 of a numerically controlled drilling machine, and the designed hole positions were corrected by considering the thermal shrinkage rate of the multilayer board in advance. Holes were drilled at the added positions. In contrast to the above methods, misalignment between the inner layer pattern and the hole as shown in Table 1 occurred. (Effects of the Invention) As described above, according to the present invention, it is possible to accurately drill holes at desired positions without correcting the hole position coordinates in accordance with the thermal contraction of the multilayer substrate. It goes without saying that according to the present invention, there is no need for a device for forcibly pulling the multilayer substrate.

[Brief explanation of the drawing]

1 and 2 correspond to the present invention, and FIG. 1 is a partially enlarged vertical cross-sectional view during lamination formation;
FIG. 2 is a partially enlarged longitudinal sectional view during drilling. Explanation of symbols, 1...lower lamination mold, 2...reference pin hole for lamination, 3...reference pin for lamination, 4...upper lamination mold, 5...disposable board for drilling, 6...release paper, 7...outer layer and inner layer base material, 8... adhesive prepreg, 9... hole punching plate, 10... hole punching drill, 11... hole punching machine sub-table, 12... inner layer pattern, 13...
Hole, 14...Multilayer board.

Claims (1)

[Scope of Claims] 1. In the step of stacking and fixing the multilayer board components between a set of stacking molds using reference pins, heating and pressurizing them to form a multilayer board, and drilling holes, the multilayer board components A disposable board for drilling is interposed between the upper laminated mold and the lower laminated mold to form a multilayer board by heating and pressurizing. A method for manufacturing a multilayer printed wiring board, characterized in that a lower laminated mold, a disposable board for drilling, and a reference pin are removed.