JP3943735B2 - Manufacturing method of build-up type multilayer printed wiring board - Google Patents

Description

【００２７】
【発明の効果】
以上の説明および表１から明らかなように、本発明の多層プリント配線板の製造方法によれば、成形時の銅箔のシワ、パターンの浮き出し発生を抑制し、銅箔外観の歩留を向上した多層プリント配線板が製造できる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a build-up type multilayer printed wiring board used for electrical equipment, electronic equipment, computers, communication equipment and the like.
[0002]
[Prior art]
Due to the recent progress in thinning and downsizing of set equipment, a build-up type multilayer printed wiring board that can realize high-density mounting and wiring is attracting attention. As one process of the manufacture, there is a build-up process in which insulating layers and wiring layers are sequentially stacked in layers by repeating hot pressing using a resin sheet with a copper foil carry. In this build-up process, due to the fact that the material of the insulating layer is a single resin that does not include a glass substrate, the following three problems that impair the yield of high-density wiring have been highlighted.
[0003]
The first point is the application of the resin to one side of the copper foil carrier, drying, cutting into a predetermined workpiece size, and loading it in the process of circuit formation yield due to adhesion of resin cutting powder to the copper foil surface. It is a decline.
[0004]
The second point is that the wiring specifications of the build-up type multilayer board are stricter than those of the conventional type, and the appearance yield is reduced due to the occurrence of a copper foil surface dent or the like during molding.
[0005]
The third point is that the resin sheet with a copper foil carry has a thin insulating layer thickness compared to a conventional glass substrate prepreg, and since it does not have a glass substrate, it has a low elastic modulus or cushioning property. It is easy to be affected by the unevenness of the inner layer circuit board, and causes wrinkles of the copper foil, embossing of the pattern and dents at the time of molding to lower the yield.
[0006]
[Problems to be solved by the invention]
The present invention has been made in view of the above-mentioned problems. The object of the present invention is to provide a build-up type multilayer printed wiring board using the above-mentioned resin sheet with a copper foil carry, wrinkles of copper foil, and embossing of patterns. It is another object of the present invention to provide a manufacturing method that can be produced with high yield without generating dents.
[0007]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above-mentioned object, the present inventor previously performed protective masking such as a PET film on the copper exposed surface of the resin sheet with a copper foil carrier for the outer layer of the build-up type multilayer printed wiring board. And using a releasable protective film on the exposed resin surface can reduce the decrease in appearance yield due to the occurrence of wrinkles during patterning, embossing of patterns and dents, etc. Since it is not affected by the resin powder at the time of cutting the copper foil, it has been found useful for preventing a decrease in yield during circuit formation, and the present invention has been completed.
[0008]
That is, the present invention
A wiring layer by repeating a process of hot-pressure molding by sandwiching a metal plate with a copper foil carry resin sheet on one or both sides of an inner circuit board on which a conductor circuit pattern has been previously formed on one or both sides. In the method for manufacturing a multilayer printed wiring board in which the copper foil is stacked, the resin sheet with a copper foil carrying the protective mask on both the copper exposed surface and the resin exposed surface of the resin sheet with the copper foil carry as the resin sheet with the copper foil carry It is the manufacturing method of the multilayer printed wiring board characterized by using this.
[0009]
Hereinafter, the present invention will be described in detail.
[0010]
Examples of the inner layer circuit board used in the present invention include inorganic fibers such as glass and asbestos, organic synthetic fibers such as polyester, polyamide, polyvinyl alcohol, and acrylic, and natural fibers such as cotton, woven fabrics, nonwoven fabrics, mats, and papers. For materials, phenol resin, cresol resin, epoxy resin, unsaturated polyester resin, melamine resin, polyimide, polybutadiene, polyamide, polyamideimide, polysulfone, polyphenylene sulfide, polyphenylene oxide, polybutylene terephthalate, polyether ether ketone, fluorine resin, etc. A laminated sheet for electrical use in which a required number of prepregs impregnated and dried with a resin such as a single product, a modified product, a mixture, etc. are laminated and a copper foil is disposed and integrated on the upper surface and / or the lower surface thereof. Formed .
[0011]
The copper foil used for the resin sheet with a copper foil carry in the present invention may be either an electrolytic copper foil or a rolled copper foil, and is not particularly limited, and the copper foil thickness is generally about 0.006 to 0.07 mm. Is. Regarding the resin used for application to the copper foil, those in the same field category as the exemplary impregnated resin of the inner layer circuit board described above are used, and are not particularly limited. About manufacture of the resin sheet with a copper foil carry, it can manufacture by apply | coating and drying resin of predetermined thickness to the single side | surface of copper foil by a conventional method.
[0012]
The protective masking of the exposed copper surface used in the present invention is a synthetic resin heat-resistant film such as a normal polyethylene terephthalate film (PET film), but is not particularly limited. The thickness of the PET film to be used is preferably in the range of 10 μm to 150 μm. If the thickness is less than 10 μm, there is little influence (effect) of the cushioning property at the time of molding, copper foil wrinkles at the time of molding, pattern relief, and the effect of suppressing the occurrence of dents are not sufficient, and the thickness is If it exceeds 150 μm, the material may be displaced during molding, which is not preferable.
[0013]
The protective masking of the exposed resin surface includes a film having releasability such as a normal polyethylene terephthalate film (PET film), an OPP film, a release paper, and the like. As long as it has no practical problem in curling and release peel strength particularly when bonded to the resin surface by thermal fusion.
[0014]
Lamination of protective masking to copper foil is performed by attaching an adhesive to one side of the film. In general, the laminating step is preferably performed before applying the resin for the resin sheet on the opposite surface, but can be performed even after application and drying of the resin for the resin sheet. The type of pressure-sensitive adhesive is not particularly limited, but there is no problem in the application of the resin for the resin sheet, the drying process and the multi-layer lamination process, and it can be peeled off from the copper foil surface after molding. It is required that there is no trouble such as.
[0015]
Lamination of protective masking on the resin surface is usually performed by applying resin for resin sheet and drying, and then bonding the release film by fusing the resin through a hot roll. Instead, it has an appropriate peel strength and can withstand sheet cutting after lamination, and the releasable film may be peeled off without any problems before lamination at the time of subsequent molding.
[0016]
The resin sheet with masking copper foil is prepared by cutting into a predetermined workpiece size according to the dimensions of the inner layer plate. With respect to press molding, a secondary material such as a cushion using a normal multi-stage press for a multilayer can be carried out in a conventional manner unless there is a problem with molding, and is not limited.
[0017]
[Action]
The manufacturing method of the multilayer printed wiring board of the present invention uses a predetermined protective masking, and suppresses the generation of resin powder and copper foil powder at the time of cutting, copper foil wrinkles at the time of molding, occurrence of pattern embossing It can be an effective method that can contribute to improving the yield of copper foil appearance such as suppression and dents.
[0018]
【Example】
EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited by these Examples.
[0019]
Example An electric circuit was formed on a double-sided copper foil of a glass cloth base epoxy resin double-sided copper-clad laminate (total thickness 0.5 mm, copper foil thickness 35 μm) to obtain an inner layer plate.
[0020]
On the other hand, TFB-4-434AS (trade name, manufactured by Fujimori Kogyo Co., Ltd.), a copper foil with a PET protective film in which a PET film (38 μm thickness) is bonded to one side of a copper foil (12 μm thickness) with an adhesive, is an epoxy resin. Was coated and dried to a thickness of 80 μm to obtain a resin sheet with a copper foil masking copper foil.
[0021]
Next, a resin sheet with a desired double-sided masking copper foil is obtained by overlaying a PET film (30 μm thick) on the resin exposed surface of the resin sheet with copper foil surface masking copper foil and heat-sealing using a hot roll. Obtained. This resin sheet with double-side masking copper foil is cut into sheets according to the size of the inner layer plate.
[0022]
The sheet-cut resin sheet with double-sided masking copper foil peels only the PET film on the resin surface, and is stacked on the upper and lower surfaces of the inner layer plate with the masking copper foil surface facing outside and sandwiched between SUS plates. To do. Ten such stacked groups were molded in multiple stages under a molding pressure of 30 kgf / cm ² and a temperature of 170 ° C. × 120 minutes, and then the copper foil surface masking was peeled off to produce 100 multilayer printed wiring boards.
[0023]
Comparative Example 1
In the examples, the resin sheet with copper foil (copper foil 12 μm thickness, epoxy resin thickness 80 μm) that does not use a double-sided PET film was used instead of the double-sided masking resin sheet with copper foil. 100 multilayer printed wiring boards were manufactured.
[0024]
Comparative Example 2
In the example, 100 multilayer printed wiring boards were produced in the same manner as in the example except that the material cut in the copper foil surface masking (only one side) resin sheet with copper foil was used.
[0025]
With respect to the multilayer printed wiring boards of Examples and Comparative Examples 1 and 2 thus obtained, the yield such as the dents on the appearance, the wrinkles of the copper foil, and the level of protrusion of the inner layer pattern were confirmed. The results are shown in Table 1, and it was confirmed that the yield of the copper foil appearance and the inner layer circuit was excellent, and the yield of forming the outer layer pattern was good in the present invention.
[0026]
[Table 1]

[0027]
【The invention's effect】
As is clear from the above description and Table 1, according to the method for manufacturing a multilayer printed wiring board of the present invention, the occurrence of copper foil wrinkles and pattern embossing during molding is suppressed, and the yield of copper foil appearance is improved. A multilayer printed wiring board can be manufactured.

Claims (2)

A wiring layer by repeating a process of hot-pressure molding by sandwiching a metal plate with a copper foil carry resin sheet on one or both sides of an inner circuit board on which a conductor circuit pattern has been previously formed on one or both sides. In the method of manufacturing a multilayer printed wiring board in which the copper foil is stacked, as the resin sheet with the copper foil carry, a copper mask surface is previously subjected to protective masking, and then the resin is coated and dried, and the exposed copper surface is subjected to protective masking on the resin surface Use the resin sheet with masking copper foil with both protective masking on both the resin exposed surface and the resin exposed surface, and remove the protective masking of the resin exposed surface of the resin sheet with masking copper foil before molding, Protective masking is a method for producing a build-up type multilayer printed wiring board, wherein the masking is removed after molding. The protective masking of the exposed copper surface in the resin sheet with masking copper foil is a polyethylene terephthalate film with a thickness of 10 μm to 150 μm adhered to the exposed copper surface. The protective masking of the exposed resin surface melts the resin on the exposed resin surface. 2. The method for producing a build-up type multilayer printed wiring board according to claim 1, wherein the film is a peelable film.