JP3593708B2 - Manufacturing method of multilayer printed wiring board - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a method for manufacturing a multilayer printed wiring board.
[0002]
[Prior art]
2. Description of the Related Art In recent years, due to an increase in the degree of integration and an increase in capacity of semiconductor integrated circuits and hybrid integrated circuits, circuit boards on which these integrated circuits are mounted have also been increasing in density. In particular, when a high integration degree and a fine pattern are required, an interlayer insulating film is formed on a ceramic substrate using a liquid heat-resistant resin by a known film forming technique and a photolithography technique. At this time, the connection between the conductor wiring boards via the interlayer insulating film is performed by forming a hole for a contact hole after the formation of the interlayer insulating film, and forming a second conductive wiring layer thereon. Hereinafter, a required number of insulating layers and conductor wiring layers are laminated to form a multilayer wiring board, and a semiconductor IC and chip components are mounted thereon to produce a required product.
[0003]
[Problems to be solved by the invention]
However, in the conventional method using a liquid resin, a spin coating process must be performed several times to obtain an insulating layer having a required thickness, and a contact hole is formed by one layer for each product. Each process had to be made, and the process was long. For this reason, although the cost by this method is very high and the reliability is high, the use of this kind of thin film multilayer board is limited.
As a method of manufacturing a thin-film multilayer board that can be manufactured at a low cost with a similar structure, using a insulating sheet having the required thickness and adhesiveness, after forming contact hole forming holes in advance before bonding, There is a manufacturing method in which a conductor wiring layer is overlapped on a required position and integrated. However, originally, the sheet-like adhesive insulating material has low rigidity, easily causes physical property deformation during handling, large displacement and deformation of the contact hole forming hole, and has been a large bottleneck for forming fine wiring. .
The present invention provides a method for manufacturing a multilayer printed wiring board that overcomes the above-mentioned disadvantages.
[0004]
The present invention, after attaching a metal foil on one surface of the insulating adhesive sheet, to form a hole for the contact hole, the inner one side not adhering a metal foil in contact with the inner layer circuit board obtained by forming a conductor wiring layer The present invention relates to a method for producing a multilayer printed wiring board, which comprises superimposing and bonding a desired position on a conductor wiring layer surface of a circuit board and then removing a metal foil.
In the present invention, the insulating adhesive sheet to be used has a molding fluidity such as a polyimide resin film so that the holes are not deformed when the holes for contact holes are bonded and integrated by pressure and heat on the conductor wiring. Use very few materials. Also for this purpose. Using a material having a 2 So構forming the adhesive formed sheets layer with no fluidity insulating sheet layer is somewhat flowable, to minimize the thickness of the adhesive molded sheet layers, it employs a method of reducing the fluidity Is also good.
The metal foil used requires a minimum thickness for obtaining rigidity, and specifically, an aluminum foil having a thickness of 30 μm or more is preferable.
[0005]
To attach the metal foil to the insulating adhesive sheet, apply a liquid resin directly on the metal foil when manufacturing the insulating adhesive sheet. By fusing. The metal foil is coated with a release agent or the like, if necessary, on the surface in contact with the insulating adhesive sheet so that it can be easily peeled off after the integrated bonding with the conductor wiring layer. The surface may have a surface treatment for reducing irregularities, such as mirror finishing, or the like. As a method of forming a contact hole forming hole of an insulating adhesive sheet with a metal foil attached thereto, in addition to a drill and a punching punching method, there is also a chemical and thermal etching method in which holes are formed only in the insulating adhesive sheet layer, The former can work on a plurality of sheets at a time and is efficient. In addition to the formation of the contact hole, a guide hole for arranging the conductor wiring layer at a required position is preferably formed in this step.
[0006]
The bonding to the conductor wiring layer is performed by the above-described guide hole or a positioning method similar to the above-described guide hole, and is bonded and formed by a press or a laminator. After the adhesive molding, the metal foil is peeled off, and a new conductor wiring layer is formed on the insulating layer of the insulating adhesive sheet by a conductor forming technique using a known plating method. Hereinafter, a required number of layers of the insulating layer and the conductor wiring layer are laminated to form a multilayer printed wiring board.
[0007]
【Example】
Next, examples of the present invention will be described.
(1) As a substrate for adjusting the inner layer circuit board, a conductive circuit is formed by photolithography and etching using a glass substrate epoxy resin laminated board having a thickness of 0.2 mm and a copper foil having a thickness of 35 μm adhered to both sides. After the formation, the copper foil surface was subjected to an oxidizing treatment to obtain an inner circuit board in which the conductor wiring layer 2 was formed on the substrate 1 as shown in FIG.
(2) Synthesis of polyimide resin 3,3 ′, 5,5′-benzophenonetetracarboxylic dianhydride and diamine components (bis [4-(-aminophenoxy) phenyl] sulfone and 4,4′-diamino-3, 3 ′, 5,5′-mixture with tetraisopropyldiphenylmethane) was subjected to a polycondensation reaction in an equimolar ratio to produce a polyimide resin. This polyimide resin has an N, N-dimethylformamide (DMF) solution having a resin content of 20% and a molecular weight of 24 Pa · s as measured by an E-type viscometer.
[0008]
(3) Preparation of Adhesive Sheet To a resin composed of 50 parts by weight of the polyimide resin synthesized above, 15 parts by weight of bismaleimide and 35 parts by weight of bisphenol A type epoxy resin, dicyandiamide as a curing agent was added to the epoxy equivalent of 1 of the epoxy resin. 0.7 equivalents and 4% by weight of dicumyl peroxide as a curing accelerator based on the resin content of the resin were added and mixed well, and heated at 100 ° C. for 8 minutes and further at 150 ° C. for 10 minutes, and the softening temperature was 110 ° C. And a thermosetting resin adhesive film (adhesive sheet) having a thickness of 20 μm.
(4) Lamination to aluminum foil Under the conditions of a molding temperature of 150 ° C., a pressure of 30 kgf / cm ² , and a time of 15 minutes, the adhesive sheet prepared as above was coated with aluminum having a surface roughness Ra of 0.3 μm and a thickness of 30 μm. Lamination of foil was performed.
[0009]
(5) Adhesion molding to inner layer circuit board As shown in FIG. 1, a 0.8 mm diameter drill hole is drilled at a predetermined position of the insulating layer 3 made of an adhesive sheet to which an aluminum foil 4 is bonded. After forming a hole 5 for pin alignment and a pin hole (guide hole, not shown) for pin lamination for alignment, a molding temperature of 180 ° C. and a pressure of 40 kgf / cm ² are adjusted to a predetermined position of the inner circuit board. After bonding for 90 minutes, the aluminum foil was peeled off.
(6) Multi-layering In the following, on the insulating layer 3 from which the aluminum foil has been peeled off, the insulating layer 3 is alternately formed on the conductive wiring layer 2 by the plating method and the adhesive sheet having the contact hole 5 simultaneously formed in (5). To produce a multilayer printed wiring board composed of three conductor wiring layers and two insulating layers.
[0010]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, displacement and deformation | transformation of the hole for contact holes are small, and it becomes possible to produce a fine wiring efficiently.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a method for manufacturing a multilayer printed wiring board according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Conductor wiring layer, 3 ... Insulating layer, 4 ... Aluminum foil, 5 ... Hole for contact hole

Claims (2)

After bonding a metal foil on one surface of the insulating adhesive sheet, to form a hole for the contact hole, the conductor of one surface which does not adhere to the metal foil in contact with the inner layer circuit board obtained by forming a conductor wiring layer the inner layer circuit board A method for manufacturing a multilayer printed wiring board, which comprises laminating on a required position on a wiring layer surface , bonding and forming , and then peeling off a metal foil. 2. The method according to claim 1, wherein the metal foil is an aluminum foil having a thickness of 30 [mu] m or more.

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