JPH0951172A - Manufacture of multilayer printed board provided with blind bias hole - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a multilayer printed board, a semiconductor carrier and a plastic semiconductor package provided with a blind bias hole which has high heat resistance, high insulation and low dielectric constant at low cost and by simple method. SOLUTION: A multilayer board, which has at least one layer of inner layer circuit and copper foil over both outermost layers, is laminated with copper plated laminated thermosetting resin board, which has heat resistant organic fiber non-woven fabric as base material, a same kind base material, prepreg, which is composed of resin, and/or copper foil. Then, laser beams are applied after forming the multilayer, and various bias holes are formed at one time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer printed circuit board, a semiconductor carrier, and a plastic semiconductor package which have a low cost, a complicated manufacturing process, a high heat resistance, a high insulating property, and a low dielectric constant blind bias hole. It relates to a manufacturing method.

[0002]

2. Description of the Related Art As a method of manufacturing a multilayer printed circuit board having blind bias holes, a 1: build-up method and a 2: lamination method of a double-sided board and a multilayer printed board are generally well known. . In the method of manufacturing a multilayer printed board having a blind bias hole in the build-up method of No. 1, a light- and thermosetting resin is applied to one side or both sides of a double-sided board or a multi-layer board on which a conductor circuit is formed. Pre-cure with heat, and then use a mask to prevent light from hitting the micro-bias holes where it will be formed. Heat cure. Then, a conductor circuit is formed by electroless plating and / or electroplating or sputtering. The above steps are repeated for more layers. Since the micro-bias holes are formed by light, the holes can be formed with high positional accuracy and high density. However, the process becomes more complicated and costly as the number of layers increases. In addition, since the photocurable resin is essential, there is a problem that the selection of the resin is limited and the degree of freedom is small in order to improve the properties such as insulation, adhesion, chemical resistance, and heat resistance.

In the relamination method for a double-sided board and a multilayer printed board, the double-sided board and the multilayer printed board are each manufactured by a known method, and laminating is performed to bond the both. After that, if necessary, a through hole is formed to connect with the conductor circuit of the adhered multilayer printed board, and then a conductor circuit is formed by electroless plating and / or electroplating to form a PWB. To do. A method using a drill is generally used for forming the through hole,
There is a limit to the ultra-small diameter drilling, and there is a limit to high density. In addition, since the relamination process and the like are indispensable, the process is complicated and the cost becomes high.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned drawbacks of a multilayer printed board having a blind bias hole, has high reliability, and its manufacturing process is almost the same as that of a normal multilayer printed board. The present invention relates to a method for manufacturing a multilayer printed board having blind bias holes which is not complicated and is low in cost.

[0005]

That is, according to the present invention, there is at least one inner layer circuit, and an upper outer layer circuit and an inner layer circuit, an upper outer layer and a lower outer layer circuit, or an inner layer circuit, or an inner layer circuit and a lower outer layer. Or a method for manufacturing a multilayer printed board in which all layers are electrically connected by at least one blind bias hole, the multilayer printed board having front and back or inner layer circuits electrically connected by through holes. A step of forming a land for conducting at least the blind bias hole by plating on the outer surface, which is the surface on one side of the plate and finally becomes the inner layer circuit, for conducting the blind bias hole To the outer layer of the multilayer printed board on which the land is formed, use a heat-resistant organic fiber non-woven fabric base thermosetting resin prepreg to bond a copper foil, or
Alternatively, by using the prepreg and using a heat-resistant organic fiber non-woven fabric base material thermosetting resin copper-clad sheet, it corresponds to the diameter of the blind bias hole substantially in the center of the inner layer circuit land where the blind bias hole is to be formed. The step of adhering the inner layer circuit board on which the inner layer circuit is formed by etching away the copper foil in the part, and the copper foil at the position corresponding to the inner layer land where the blind bias hole on the outermost copper foil surface is to be formed Smaller than the size of the diameter of the blind bias hole, the step of etching away the copper foil, the heat-resistant organic fiber non-woven fabric base material, the thermosetting resin, and the energy required to remove the insulation thickness of the insulation layer. Brazing is performed by irradiating a gas laser from the outermost layer surface to form blind bias holes, electroless plating, and / or electroplating. A method for manufacturing a multilayer printed circuit board having a blind bias hole comprises the step of forming the outer circuit to process and finally both outermost layers to deposit a plating layer on the command bias hole.

That is, a feature of the present invention is that a heat-resistant organic fiber non-woven fabric base material thermosetting resin copper-clad is applied to a multilayer board in which one or more inner layer circuits are formed and both outermost layers are entirely copper foil layers. Laminated sheets and the same type of base material, prepreg made of resin, and / or laminated using a copper foil to form a multilayer,
Furthermore, we perform relamination with both sides or multilayer board,
The problem is solved by irradiating a laser beam and forming various bias holes at once.

The heat-resistant organic fiber nonwoven fabric in the present invention is preferably liquid crystal polyester fiber. The liquid crystal polyester non-woven fabric is a non-woven fabric using liquid crystal polyester based fibers obtained by spinning a liquid crystal polyester based resin. Further, the liquid crystal polyester resin is a polymer capable of forming an anisotropic molten phase. The liquid crystal polyester fiber is not particularly limited, but a fiber made of wholly aromatic polyester (that is, polyester whose main chain is composed of repeating units of aromatic rings) resin is preferable. Therefore, the aromatic diol,
A resin obtained by appropriately combining an aromatic dicarboxylic acid and / or an aromatic hydroxycarboxylic acid. Among these, a polyester copolymer of p-hydroxybenzoic acid and 2-hydroxynaphthalene-6-carboxylic acid has excellent balance of spinnability and heat resistance, and therefore can be preferably used, and p-hydroxy A polyester copolymer of benzoic acid, terephthalic acid, and 4,4'-hydroxyphenyl has excellent heat resistance and can be preferably used. Further, the above-mentioned liquid crystal polyester nonwoven fabric may be appropriately treated with plasma treatment, calendar treatment, or sequin.

The thermosetting resin composition is a known epoxy resin, cyanate resin, phenol resin, polyester resin, acrylic resin, polybutadiene resin, diallyl phthalate resin or other thermosetting resin, or a mixture of two or more thereof. And a known curing agent for these resins, a catalyst, or a composition obtained by mixing a solvent as the case requires, and for modification, rubbers such as acrylonitrile-butadiene rubber, polybutadiene resin, etc. The thermosetting and thermoplastic resins mentioned above, and dyes, surfactants, defoaming agents, coupling agents and the like may be mixed.

A solution of the above-mentioned thermosetting resin composition in a heat-resistant organic fiber non-woven fabric or a liquid solvent-free solution can be impregnated and dried by a known method. The amount of resin at this time is 40 to 70
The wt% and the molding thickness are preferably 0.03 to 0.25 mm.

In the blind bias hole drilling by laser irradiation, in order to shield the portion which is not desired to be irradiated with laser light from the laser light, only the portion to be irradiated with the outermost copper foil of the multilayer printed board should be removed by etching or the like. Thereby forming a blind bias hole.

A carbon dioxide gas laser or an excimer laser can be used as a laser for forming a blind bias hole with a laser beam, but a carbon dioxide gas laser is preferable. The carbon dioxide gas laser irradiation conditions represent the irradiation fluence (energy density) of the laser. The M value (reduction ratio) is 5 to 20, preferably 8 to 14. The number of pulses is uniquely determined by the thickness of the electrically insulating layer to be removed, the processing speed, and the irradiation fluence.

According to the present invention, a multilayer printed board having a blind bias hole can be manufactured without complicated manufacturing steps.
It can be manufactured at low cost.

The detailed manufacturing method of the present invention will be described with reference to the drawings. The prepreg 3 in FIG. 1 is obtained by impregnating a liquid crystal polyester non-woven fabric (consisting of p-hydroxybenzoic acid and 2-hydroxynaphthalene-6-carboxylic acid) with a thickness of 0.06 mm with an epoxy resin composition by a known method and curing it. Obtained.

A 35 μm electrolytic copper foil was laminated on both sides of the obtained prepreg, and the pressure was 1.96 MPa (20 kgf / cm ² ).
Laminated and molded under the conditions of 180 ℃ for 2 hours, insulation layer thickness 0.06mm
A double-sided copper clad laminate was obtained. A circuit was formed on the obtained double-sided copper clad laminate by a known method to obtain a conductor circuit sheet 1 and a conductor circuit 2. At this time, as shown in FIGS. 1 and 2, the copper foil land having a shape in which the copper foil in the portion corresponding to the diameter of the blind bias hole is removed by etching is located at the lowest part of the blind bias hole. Copper foil land with a diameter larger than the size of
-(a)), and in the intermediate layer circuit immediately above the lowest copper foil land, a copper foil land having a diameter larger than the diameter of the blind bias hole is formed. A copper foil land (FIG. 1: 1- (b)) is formed by etching away the copper foil in a portion corresponding to the diameter of the blind bias hole in the central portion.

In order to provide the inner layer land directly above the inner layer land (FIG. 1: 2- (c)) where the portion corresponding to the diameter of the blind bias hole is removed by etching, the inner layer land (2-
Inner layer formed by removing the copper foil in the center of the inner layer land so that the copper foil in the portion corresponding to the diameter of the blind bias hole formed in (c)) is larger than the diameter of the blind bias hole that has been etched away. Land: (Fig. 1: 2- (d)) is formed, and further on the layer directly above the inner layer land (2- (d)),
An inner layer land (FIG. 1: 1- (e)) was formed by etching away a portion corresponding to the diameter of the blind bias hole. The area of the inner layer land (1- (e)) that has been etched away is smaller than the size of the inner layer land (2- (d)) immediately below it, and the inner layer land (2- (d)) has been etched away. It was formed larger than the part. Similarly, inner layer lands (FIG. 1: 1- (f), 2- (f)) in which the portion corresponding to the diameter of the blind bias hole was removed by etching were also formed. The upper layer is larger in the inner layer land where the copper corresponding to the blind bias hole is removed by etching. Even if some deviation occurs, it is an indispensable condition for improving the reliability of the blind bias hole by the laser processing described below.

The resulting prepreg 3, inner layer circuit sheet 1, inner layer circuit sheet 2 and 18 μm electrolytic copper foil were stacked in the configuration shown in FIG. A 2.0 mm stainless steel plate is placed on the upper and lower surfaces of the stacked materials, and the pressure is 2.94 MPa (30
(kgf / cm ² ), 180 ° C., and laminated for 2 hours to obtain a multilayer circuit board. The outer layer copper foil which finally becomes the inner layer circuit of the obtained multilayer circuit board was formed by using a known method to remove the copper foil having a size corresponding to the diameter of the blind bias hole by etching to form an inner layer land (FIG. 2). ). The size of this inner layer land is larger than the size of the portion of the intermediate layer circuit immediately above where the copper foil is removed by etching, and the size of the portion where the portion corresponding to the diameter of the blind bias hole is removed by etching. The size is smaller than the size of the portion on the intermediate layer circuit immediately above.

A double-sided circuit board in which the front and back sides are electrically connected by through holes, and the copper foil surface, which is finally the outermost layer of the double-sided circuit board, is entirely covered with copper foil except for the through-hole portions. The copper foil surface, which is the surface opposite to the copper foil surface, which will eventually become the intermediate layer circuit, was produced by etching away the copper foil by a known method to connect the land for conduction with the blind bias holes of the above-mentioned multilayer circuit board. (Figure 3).

The multilayer board of FIG. 2 and the double-sided circuit board having through holes of FIG.
A prepreg 3 is inserted between them, and 2.0 mm stainless steel plates are arranged on the upper and lower surfaces of the stacked materials,
A multilayer circuit board was obtained by laminating and molding at a pressure of 1.96 MPa (20 kgf / cm ² ), 180 ° C. for 2 hours. In addition, at the time of this lamination molding,
In order to prevent the resin of the prepreg 3 from flowing into the through holes of the double-sided circuit board having through holes and exuding between the outermost copper foil and the stainless steel plate, the outermost copper foil and the stainless steel plate are separated from each other. It can also be produced by using a structure having a property.

The outermost copper foil layer corresponding to the uppermost portion of the obtained multilayer circuit board was etched and removed by a known method at a portion corresponding to the diameter of the blind bias hole. At this time, the size of the copper foil portion removed by etching is smaller than the diameter of the inner layer circuit land directly below the portion to be removed, and substantially the center of the land directly below is formed larger than the diameter of the portion removed by etching. A multilayer circuit board for laser processing was used (Fig. 4).

Carbon dioxide laser for laser processing multilayer circuit board (Sumitomo Heavy Industries, Ltd., IMPACTRASER: IMPACT2150)
The blind bias holes were processed by using. The copper clad laminate thus obtained was plated to form a conductor circuit, and a printed board was formed. (Fig. 5)

As is clear from the detailed description of the present invention and the detailed manufacturing method thereof, according to the method of manufacturing a multilayer printed board having a blind bias hole, one or more inner layer circuits are formed and both inner layers are formed. Using a heat-resistant organic fiber non-woven fabric substrate thermosetting resin copper clad laminate and a substrate of the same kind, a prepreg composed of resin, and / or a copper foil By laminating and stacking to make multiple layers, and then performing relamination with a double-sided circuit board having through holes or a multilayer circuit board, and making a multilayer structure by irradiating laser light and forming various bias holes at once. It is possible to manufacture a multilayer printed circuit board with a blind bias hole that can add high heat resistance, high insulation, low dielectric constant and high functionality at low cost, without complicated manufacturing process, its significance is extremely high. It is high.

[Brief description of drawings]

FIG. 1 is a cross-sectional perspective view schematically showing a layer structure used for manufacturing a multilayer printed board having an inner layer land in which a portion corresponding to the diameter of a blind bias hole of the present invention is removed by etching.

FIG. 2 shows a copper foil layer corresponding to a blind bias hole diameter in a copper foil layer which finally becomes an inner layer circuit of a multilayer circuit board having an inner layer land in which a portion corresponding to a diameter of an integrated blind bias hole is removed by etching. It is sectional drawing which showed typically the multilayer circuit board in which the inner layer land removed by etching was created.

FIG. 3 schematically shows a state in which a land for conducting the copper foil surface of the double-sided circuit board, which is electrically connected to the front and back sides by through holes, to finally become the intermediate layer circuit with the blind bias hole of FIG. 2 is formed. FIG.

FIG. 4 is a cross-sectional view showing a state in which the outermost copper foil on the upper surface of the integrated multilayer board is removed by etching in order to use it for laser light irradiation.

FIG. 5 is a cross-sectional view schematically showing a multilayer printed board having a blind bias hole by laser light irradiation processing.

[Explanation of symbols]

1: Inner layer circuit sheet with copper foil lands (b, e, f) and copper foil lands (a) formed by etching away the copper foil in the area corresponding to the blind bias hole diameter 2: Blind bias hole diameter Copper foil land (c, d, f) formed by etching away the copper foil in the area corresponding to 3) Inner layer circuit sheet 3: Heat-resistant organic fiber non-woven fabric base thermosetting resin prepreg 4: Copper foil

Claims (2)

[Claims] 1. A conductor layer having a blind bias hole and a circuit having two or more layers is formed on both surfaces having a through hole or on at least one surface of a multilayer printed wiring board, and the circuits of each layer are electrically conductive. A method for manufacturing a multilayer printed circuit board, comprising: a multilayer printed circuit board in which front and back surfaces or an inner layer circuit are conducted through a through hole, which is a surface on one side of the multilayer printed circuit board, and finally becomes an inner layer circuit. , A step of forming at least a land for conduction with the blind bias hole on the outer layer surface by plating, a heat-resistant organic fiber non-woven fabric substrate is provided on the outer layer of the multilayer printed board on which the land for conduction with the blind bias hole is formed. Use a thermosetting resin prepreg to bond copper foil,
Alternatively, by using the prepreg and using a heat-resistant organic fiber non-woven fabric base material thermosetting resin copper-clad sheet, it corresponds to the diameter of the blind bias hole substantially in the center of the inner layer circuit land where the blind bias hole is to be formed. The step of adhering the inner layer circuit board on which the inner layer circuit is formed by etching away the copper foil in the part, and the copper foil at the position corresponding to the inner layer land where the blind bias hole on the outermost copper foil surface is to be formed Smaller than the size of the diameter of the blind bias hole, the step of etching away the copper foil, the heat-resistant organic fiber non-woven fabric base material, the thermosetting resin, and the energy required to remove the insulation thickness of the insulation layer. Brazing is performed by irradiating a gas laser from the outermost layer surface to form blind bias holes, electroless plating, and / or electroplating. Method for manufacturing a multilayer printed circuit board having a blind bias hole in steps and finally both outermost layers to deposit a plating layer on the command bias hole comprises the step of forming an outer layer circuit. 2. A method for producing a multilayer printed board, wherein the heat-resistant organic fiber nonwoven fabric substrate according to claim 1 has a blind bias hole which is a liquid crystal polyester nonwoven fabric.