JPH0529764A - Manufacture of multilayer printed wiring board - Google Patents

Abstract

PURPOSE:To eliminate the generation of dimensional changes after the manufacture of a multilayer printed wiring board or internal stress by protecting a thermosetting prepreg board, which is interposed as a joint between inner layer boards or an inner layer board and an outer layer board, from imperfect hardening in a manufacturing process of multilayer printed boards by hot press. CONSTITUTION:In a manufacturing method of a multilayer printed board where a joint prepreg is interposed between inner layer boards 1 laminated by several pieces and/or between the inner layer board 1 and outer layer board 2 on which the outer layer board 2 is laminated on the top layer and the bottom layer and laminated by means of a hot press, a prepreg material 3 which has formed a thermosetting resin layer 5 prior to heat curing is interposed between the front and rear sides of a thermoset base material 4 which impregnates thermosetting resin in heat-resistant woven cloth, unwoven fabric and a fiber-like core layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit pattern portion such as an energizing pattern and an insulating pattern in a multi-layered state (an outer layer board, a prepreg material in order from the bottom layer, and then an inner layer board and a prepreg material constituting several other layers. The present invention relates to the production of a multilayer printed wiring board which is repeatedly laminated in this order and is finally laminated in a multilayer state in which an outer layer board is laminated on the uppermost layer.

[0002]

2. Description of the Related Art Generally, in laminating and manufacturing a multilayer printed circuit board by heating and pressing, as a preparatory step before starting the laminating process, an outer layer is used to obtain a highly accurate multilayer printed circuit board. The upper and lower relations due to the superposition of the circuit patterns formed in advance on the plate and the inner layer plate, a plurality of inner layer plates on which the circuit patterns are formed by previously forming the reference holes, and the reference holes are formed in advance. A prepreg plate (a sheet for thermosetting resin interlayer bonding) and a reference pin at a fixed position (at least two alignment pins) in a predetermined order (from the lower layer to the inner layer plate, the prepreg material, the inner layer plate,
Align the circuit patterns between the inner layer boards by inserting them according to the order of the prepreg material), heat and press these to bond and fix the inner layer boards, and then fix them. On the lowermost layer and the uppermost layer of the inner layer plate, an outer layer plate in which reference holes are preliminarily drilled through a prepreg plate is laminated, aligned by using the reference pin, and heated and pressed to adhere. Thus, a multilayer printed wiring board in which a plurality of inner layer boards and outer layer boards are laminated on the uppermost layer and the lowermost layer thereof is manufactured.

In the laminating process by heating and pressing in the above manufacturing process, a plurality of inner layer plates, thermosetting prepreg plates, and outer layer plates stacked with reference pins are temporarily fixed with reference pins inserted into each other. Was
Although it is heated and pressure-pressed without causing positional displacement, volume reduction and dimensional change occur due to the progress of thermosetting reaction of the prepreg plate due to high temperature heating.

In particular, the above prepreg plate is obtained by impregnating a glass cloth (core layer) with a thermosetting epoxy resin and solidifying it with a curing agent, and the epoxy resin which exists independently on the front and back of the core layer. The layer thickness is about several% to 10% with respect to the core layer thickness, and this single epoxy resin layer is
It is considered that the stress in the shrinking direction of the prepreg plate is generated.

In addition, in the multilayer printed circuit board after the bonding production, the thermosetting prepreg plate is not fully cured due to insufficient heating during the production, and the soldering process for the multilayer printed circuit board after the production is performed. Due to the heating at the time, the curing reaction progresses again and dimensional changes such as dimensional shrinkage easily occur,
Therefore, the multilayer printed circuit board body is likely to be accompanied by internal stress and distortion.

The cause of such dimensional fluctuations and occurrence of internal stress is largely due to imperfect thermal curing of the prepreg plate in the inner layer portion of the multilayer printed circuit board. The dimensional fluctuation rate and the magnitude of internal stress are The larger the ratio of the total volume of the uncured prepreg plate to the total volume of the printed circuit board, the larger the ratio.

[0007]

DISCLOSURE OF THE INVENTION The present invention provides a method for producing a multilayer printed circuit board by heating and pressing,
The thermosetting prepreg plate to be interposed as a bonding material between the inner layer plates or between the inner layer plate and the outer layer plate, by preventing incomplete curing, by dimensional change after manufacturing the multilayer printed wiring board, The purpose is to eliminate the occurrence of internal stress.

[0008]

DISCLOSURE OF THE INVENTION The present invention provides a multi-layer print in which a prepreg material for joining is interposed between a plurality of laminated inner layer plates and / or between an inner layer plate and an outer layer plate and they are bonded by a heat and pressure press. In the method for producing a substrate, a heat-resistant woven fabric, a non-woven fabric, a thermosetting base material in which a fibrous core layer is impregnated with a thermosetting resin (4), the front and back, the thermosetting resin layer before thermosetting (5 ) Is formed on the prepreg material (3) with the prepreg material (3) interposed, and the prepreg material (3) is bonded by a heat and pressure press.

[0009]

EXAMPLES The present invention will be described in detail with reference to Examples.
FIG. 1 is a side view illustrating a manufacturing method according to an embodiment of the present invention, in which a lower press plate (10) of a heating and pressing means is
Place the outer layer plate (2) and prepreg material (3) on the outer layer plate (2).
One or more inner layer plates (1) are placed on the inner layer plates (1) through the prepreg. Finally, the inner layer plate of the top layer
(1) The outer layer board (2) is placed on the top of the prepreg material (3) to set the multilayer laminated board (20).

Then, the outermost plate (2) of the uppermost layer and the upper press plate (11) of the upper heating and pressing means and the lower press plate (1)
The inner layer plates (1) are bonded to each other and the inner layer plate (1) and the outer layer plate (2) are bonded to each other by heating and pressurizing between them.

In the method of the present invention, in the case of laminating a laminated inner layer plate (21) in which only a plurality of inner layer plates (1) are laminated, or in a partially laminated inner layer plate in which a plurality of inner layer plates (1) are laminated. When laminating (22), or laminating the partially laminated inner layer plates (22) to each other, or laminating the inner layer plate (1) and the outer layer plate (2) alone, etc. The above-mentioned prepreg material (3) is interposed between the above and the above prepreg material and the above-mentioned heating and pressing means are used for bonding.

The inner layer plate (1) and the outer layer plate (2) are laminated on one side or both sides of an insulating substrate such as bakelite with copper foil, and the copper foil is pattern-etched by a photo-etching method to form one side or both sides. The desired wiring pattern made of copper is formed.

The prepreg material (3) is obtained by impregnating or laminating an insulating fiber material such as glass with a thermosetting resin such as an epoxy resin and solidifying the material. The heating temperature is around 130 ° C to 200 ° C. By heating for about 3 to 80 minutes, the solidified state is once softened and at the same time heat-cured by the progress of the heat condensation reaction. In the heating and pressing press, the prepreg material (3) is provided between the inner layer plate (1) or between the inner layer plate (1) and the outer layer plate (2) by one or two pieces or several pieces. It is to interpose a sheet.

Prepreg material used in the method of the present invention (3)
As shown in Fig. 2, the sheet-shaped thermoset base material (4)
And the uncured resin layers (5) and (5) are formed on the front and back sides thereof.

As the thermosetting base material (4), inorganic fibers such as glass and asbestos, organic synthetic fibers such as polyester and polyamide, heat-treated cotton, natural fiber woven cloth and paper materials such as hemp, or these materials Composite material thickness 50μ
Sheet-like fibers of about m to 250 μm, woven fabric material, thermosetting resin (eg phenol resin, cresol resin,
An epoxy resin, an unsaturated polyester resin, a melamine resin, a polyimide resin, a mixed resin thereof, a modified resin, or the like) is mixed with a curing agent, if necessary, and then impregnated and then cured by heating. For example, a sheet-shaped glass epoxy prepreg material obtained by impregnating a glass cloth with an epoxy resin is cured almost or completely to a thickness of 8
0 μm to 120 μm (or, for example, 50 μm to 250 μm
The thermoset base material (4) formed in the above) is used.

As the uncured resin layer (5) which is cured by heat, the above thermosetting resin mixed with or without a curing agent is applied to the front and back of the base material (4), which is a liquid that does not solidify. , Or by solidifying with a curing agent (for example, a curing agent is not mixed in the epoxy resin, an uncured thermosetting resin layer (5), (5) which can be cured only by a thermosetting reaction, or An epoxy resin mixed with an amine-based curing agent, which is an uncured thermosetting resin layer (5), (5) that can be cured in two steps by solidifying it with a curing agent and then heat curing. 5 μm to 10 μm (or 1 μm to
It is applied to a thickness of about 100 μm).

The thickness of the cured base material (4) forming the prepreg material (3) is, for example, 1/10 or less of the thickness of the uncured resin layers (5) and (5). The cured substrate (4) constitutes most of the thickness of the prepreg material (3).

As one embodiment of the method of the present invention, a structure in which uncured layers (5) and (5) of epoxy resin containing no curing agent are formed on the front and back sides of a thermosetting base material (4) as a glass epoxy material. The prepreg material (3) is used for each inner layer plate (1),
(1) and between the inner layer plate (1) and the outer layer plate (2) with the prepreg material (3) interposed between them under heat and pressure to press the prepreg material (3) in an uncured state. Thermosetting resin layer (5), (5)
Heat cure and bond.

As the heating / pressurizing press conditions in the production of a laminated printed wiring board, the heating temperature is, for example, 13.
Around 0 ℃ ~ 200 ℃ (Lower press board for heating and pressing (10)
And the upper press machine (11)), the heating time is, for example, 3 minutes to 80 minutes.
About 15 minutes, the press pressure is, for example, 15 kg / cm ^{2 to} 30 kg
It is about / cm ² , and the material is once softened from the solidified state and is thermally cured by the progress of the curing reaction at the same time.

In this case, only the uncured thermosetting resin layers (5), (5) are thermally melted by hot pressing, and each layer (inner layer plate, outer layer plate) facing the uncured resin layer (5). It will be heat-cured in a state in which the adhesion to the surface of is improved. During that time, the thermoset base material (4) (glass epoxy material) remains in the thermoset state, and therefore the bonding and bonding between the layers is performed in the uncured thermosetting resin layer (5), (5). The thickness of the laminated multilayer printed wiring board is determined by only the above) and is substantially determined by the thickness of the thermoset base material (4).

Regarding the dimensional change (shrinkage), the thickness (volume) of the uncured resin layer (5) which is the source of shrinkage stress (internal stress) is the thickness of the thermoset base material (4). Since it is 1/10 or less than the volume (volume), the stress generation is also reduced to 1/10 or less, and the planar dimensional shrinkage ratio is 0.04% in the X direction before and after thermosetting by a hot press and 0 in the Y direction. Although it was 0.01%, it decreased to about 0.005% in both the X and Y directions.

Next, as another embodiment of the present invention, a thermosetting base material (4) as a glass epoxy material is used, and an epoxy resin is mixed with a curing agent (such as an amine type curing agent) in an uncured state. The prepreg material (3) having a structure in which the thermosetting resin layers (5) and (5) are formed is used, and the uncured resin layer (5) is used.
Is either a thermosetting resin layer (5) before solidification with a curing agent or a thermosetting resin layer (5) after solidification,
The thermosetting resin layers (5) and (5) in the uncured state are thermoset by heating and pressing to bond and bond them.

Uncured thermosetting resin layer containing a curing agent
(5), in the above other examples using the prepreg material (3) coated with (5), the uncured resin layer (5) by the curing agent,
In the state where the solidification reaction of (5) does not proceed completely, it is possible to bond the multilayer printed boards by the following method.

First, a multi-layer laminated plate in which a plurality of inner layer plates (1) and outer layer plates (2) are stacked via the prepreg material (3).
(20) or inner layer plate (1) through the prepreg material (3)
A laminated inner layer plate (21) in which the inner layer plates (21) are superposed on each other or a partially laminated inner layer plate (22) in which the inner layer plate (1) is partially laminated via the prepreg material (3) is pressed by a pressure press means. However, the uncured thermosetting resin layer of the prepreg material (3)
(5), (5) is solidified only with a curing agent, and after laminating each of the laminates, it is heat-pressed to heat-harden the solidified uncured thermosetting resin layer (5), (5) It is made to stick together.

[0025]

In the method of the present invention, most of the prepreg material in the thickness direction is occupied by the already cured prepreg material, and the prepreg material is used for bonding with a heating and pressing press. The only part that undergoes a heat-curing reaction during heat-pressing is the uncured layer that has been applied to the front and back of the prepreg base material that has been pre-cured with a relatively thin thickness.

The portion of the prepreg material that undergoes a curing reaction when heated and pressed is a very small volume portion of the prepreg base material surface layer portion material. Can reduce stress and dimensional changes.

Further, at the time of laminating and pressing, since only the uncured layer on the surface layer of the prepreg material needs to be cured, the curing reaction can proceed rapidly, and complete curing in a comparatively short time compared to the conventional case. It is possible to avoid the occurrence of dimensional change and distortion due to the after-curing reaction in the process involving heating operation such as soldering after the multi-layered printed wiring board is laminated.

[0028]

INDUSTRIAL APPLICABILITY The present invention uses a prepreg material in which a thermosetting resin layer having a small layer thickness and not uncured is formed on the front and back of an insulating thermosetting prepreg material and laminated in multiple layers. A multilayer printed wiring board is manufactured by heating and pressing an inner layer board and an outer layer board on which a combined wiring pattern is applied, and the uncured resin layer of the prepreg material is made thin. As a result, the heat-cured portion can be significantly reduced as compared with the conventional case, so that it is easy to shorten the heat-curing treatment time by the heat and pressure press and achieve complete curing.

Further, it is possible to reduce the strain stress generated inside the laminated wiring board due to the reduction of the dimensional change rate before and after the heat curing of the prepreg material, and it is possible to significantly improve the manufacturing efficiency and accuracy of the multilayer printed wiring board. It is something that can be demonstrated.

[Brief description of drawings]

FIG. 1 is a side view for explaining a laminated state of a heating and pressing means and a multilayer printed wiring board material for explaining the method of the present invention.

FIG. 2 is a side sectional view of a prepreg material used in the method of the present invention.

[Explanation of symbols]

1 ... Inner layer plate 2 ... Outer layer plate 3 ... Prepreg material 4 ... Thermosetting prepreg base material 5 ... Thermosetting resin layer 10 ... Lower press platen 11 ... Upper press platen 20 ... Multilayer laminated plate 21 ... Laminated inner layer plate 22 ... Part Laminated inner layer board A ... Enlarged view

Claims (1)

Claims: 1. A prepreg material for joining is interposed between a plurality of laminated inner layer plates and / or between an inner layer plate and an outer layer plate,
In a method for manufacturing a multilayer printed circuit board that is bonded by a heat and pressure press, a heat-cured base material obtained by impregnating a thermosetting resin in a heat-resistant woven fabric, non-woven fabric, or fibrous core layer (4) A method for manufacturing a multilayer printed wiring board, which is characterized in that the prepreg material (3) on which the thermosetting resin layer (5) is formed is pasted together by heating and pressing.