JPH08250856A - Method for manufacturing copper-clad laminate for printed wiring board - Google Patents

Abstract

(57) [Abstract] [Objective] The present invention provides a method for efficiently producing a copper-clad laminate for a printed wiring board having a three-layer structure consisting of a steel sheet having excellent adhesiveness and solder heat resistance, an insulating resin, and a copper foil. provide. [Structure] A steel strip having a semi-cured UV-curable resin on one side is preheated, and the semi-cured UV-curable resin and a semi-cured epoxy resin applied and dried on one side of the copper foil strip are used. It is crimped with a roll to make a laminated plate with a three-layer structure of steel strip, insulating resin consisting of both resins, and copper foil strip. The laminated strip with this three-layer structure is sheared to an appropriate size, and then this three-layer structure In the method for producing a copper-clad laminate for a printed wiring board, which comprises heating the laminate in a heating furnace to completely cure the insulating resin, a semi-cured state of the epoxy resin coated and dried on one side of the copper foil strip is applied. The heating weight loss rate in heat treatment at 200 ° C. for 20 minutes is adjusted to 0.5 to 1.25%, and the ambient temperature is maintained in a single plate state without stacking the three-layer laminated plates. 20 to 4 by continuously charging to a heating furnace of 150 to 200 ° C It is heat-cured for 0 minutes in the furnace.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a copper-clad laminate for a printed wiring board having a three-layer structure of a steel plate, an insulating resin, and a copper foil. The present invention relates to a method for efficiently manufacturing a copper-clad laminate for a printed wiring board having a three-layer structure made of copper foil.

[0002]

2. Description of the Related Art Conventionally, for example, a laminated plate having a structure of a steel plate, an insulating resin, and a copper foil has been manufactured by a hot pressing method of heating and pressurizing. That is, steel plates, insulating resin sheets, and copper foils (or copper foils with insulating resin) as raw materials are stacked and placed in a hot press, heated and pressed for 2 to 4 hours, and then cooled. Take out from the hot press to make a copper clad laminate for printed wiring boards.

This hot pressing method has a problem that it is not possible to say that it is a highly productive manufacturing method because it is necessary to manually stack the materials one by one, and a large number of materials cannot be stacked. Therefore, the present applicant has filed Japanese Patent Application Laid-Open No. 3-292.
No. 796, a steel strip having a semi-cured UV-curable resin on one side is preheated, and the semi-cured UV-curable resin is applied to one side of a copper foil strip. A resin, that is, soft resin, is pressure-bonded with a roll to form a three-layer laminated strip of steel strip, an ultraviolet curing resin and an epoxy resin, and a copper foil strip. For example, 60 sheets of the laminated plate of three-layer structure are piled in a heating furnace after being sheared to a size, and the ultraviolet rays in a semi-cured state are passed while passing through the heating furnace at a temperature of 150 ° C. for, for example, 4 hours. A technique for manufacturing a copper-clad laminate for a printed wiring board by completely curing an insulating resin composed of a cured resin and an epoxy resin is provided and disclosed.

[0004]

However, even in this direction, there is still a work of stacking and disassembling (disassembling the stacked substrates) the laminated plates before and after the heat curing treatment.
There was a problem that it took time and effort. Therefore, in order to omit the steps before and after the heat curing treatment, a method of heat curing the laminated plates without stacking was examined. JP-A-3-29
The laminated plates shown in Japanese Patent No. 2796 are connected and charged into a heating furnace in a single plate state without being stacked, and the method is disclosed in Japanese Patent Laid-Open No.
Good quality could be obtained by carrying out the heat-curing treatment at a temperature of 150 to 200 ° C. for 2 to 5 hours shown in Japanese Patent No. 292796.

However, in order to shorten the heat-curing treatment time, the short-time heat-curing treatment of the laminated plate disclosed in the above-mentioned Japanese Patent Laid-Open No. 3-292796 could not obtain good quality. That is, the laminated plate which was subjected to the heat curing treatment for a short time had a flaw on the copper foil surface, and it was difficult to secure a good copper foil appearance. In addition, when the solder heat resistance test was performed, there was a problem that the insulating resin was easily peeled off, and from the result of observing the cross section of the insulating resin, there was a problem that the epoxy resin coated on the copper foil had blisters. .

The present invention has been made as a result of extensive studies on the above-mentioned problems, and in a laminated plate composed of a steel sheet, an insulating resin and a copper foil, a semi-curing of an epoxy resin applied to a copper foil and dried. By adjusting the condition, the copper foil can be continuously charged in a single plate state without being stacked and heat-cured for a short time, so that the appearance of the copper foil is good, and the adhesiveness and solder heat resistance are high. It is an object of the present invention to provide a method for manufacturing a laminated board which secures

[0007]

The means of the present invention for achieving the above object are as follows. Preheat a steel strip with a semi-cured UV-curable resin on one side, and press-bond the semi-cured UV-curable resin and a semi-cured epoxy resin on one side of a copper foil strip with a roll. Let me
Steel strips ・ Insulation resin consisting of UV-curing resin and epoxy resin ・ Copper foil strips are made into a three-layer laminated layer, the three-layer laminated layer is sheared to an appropriate size, and then this three-layer laminated layer is laminated. In a method for producing a copper-clad laminate for a printed wiring board in which a board is heated in a heating furnace to completely cure an insulating resin, a semi-cured state of an epoxy resin applied and dried on one surface of the copper foil strip is set to 200 The heating weight loss rate in the heat curing treatment at 20 ° C. for 20 minutes is adjusted to 0.5 to 1.25%, and the ambient temperature is maintained in a single plate state without stacking the three-layer laminated plates. A method for producing a copper-clad laminate for a printed wiring board, which comprises continuously charging in a heating furnace at 150 to 200 ° C. and heat-curing for 20 to 40 minutes in the furnace.

[0008]

First, the materials used in the method for producing a copper clad laminate for a printed wiring board according to the present invention will be described. As the steel strip, it is desirable to use a silicon steel plate or a normal steel plate having a thickness of 0.2 to 1.2 mm. As a pretreatment of the steel strip, for example, electrogalvanization is applied to both surfaces, and chromate treatment is applied to both surfaces. Can be used. Next, an ultraviolet curable resin is coated on this upper surface. By coating, the copper foil can have an appearance without any flaws by pressure bonding with an insulating resin coated on a copper foil strip described later.

The thickness of the copper foil is preferably 9 to 70 μm. The insulating resin coated on the copper foil band is an epoxy resin having good soldering heat resistance, but the thickness of the entire insulating resin is required to be the required electrical conductivity. It is preferably determined from the insulating property, and it is preferable that the UV curable resin applied to the steel strip and the epoxy resin applied to the copper foil are combined to have a thickness of 30 to 120 μm.

Next, a method for manufacturing a copper clad laminate for a printed wiring board according to the present invention will be described with reference to a manufacturing apparatus example shown in FIG. Although not shown here, an ultraviolet curable resin is applied to one surface of the steel strip, and is semi-cured by irradiation of ultraviolet rays, and then a semi-cured ultraviolet curable resin that is preheated together with the steel strip,
A semi-cured epoxy insulating resin that has been applied to one side of a copper foil strip and dried is pressed by a heating roll to form a three-layer laminated strip of steel strip, insulating resin, and copper foil strip.

Then, the laminated plate 1 (see FIG. 2) having a three-layer structure in which the laminated band is sheared to an appropriate size is singly attached to a support frame 8 attached to a conveyor 7 as shown in FIG. The semi-cured UV curable resin 3 applied to the steel plate 2 by leaning it in a plate state, continuously inserting it, and passing it through the heating furnace 9.
The semi-cured epoxy resin 5 coated on the copper foil 4 is completely cured to form the insulating resin 6.

Although not shown in the figure, the conveyor is a flat belt type, placed on the belt without stacking the laminated plates, and half-cured while passing through the heating furnace in a free state without applying pressure. It is also possible to completely cure the insulating resin in the state. Although the laminated plates are arranged in one row in the width direction of the furnace in FIG. 1, they may be inserted in a plurality of rows as much as possible.

With respect to the heat-curing property of the insulating resin, the ultraviolet-curing resin has a high curing speed, and the entire composition is cured in a short time. On the other hand, the curing of thermosetting epoxy resin requires long time, high temperature, or the presence of a high concentration of catalyst, but as described above, it is mounted in a single plate state without stacking. In a short-time heat-curing treatment, the degree of curing of the epoxy resin before heat-curing was changed.

That is, the thermosetting reaction was advanced by the drying treatment of the epoxy resin applied to the copper foil strip to bring the semi-cured state close to the B stage state but the C stage state. Therefore, it was found that good quality can be obtained by heat curing treatment for a short time.

That is, the semi-cured state of the epoxy resin applied and dried on one surface of the copper foil strip of the present invention is a quantification index of 200% at 20 ° C. for 20 minutes and the weight loss rate by heating is 0.
It is necessary to adjust it to 5 to 1.25%. If the heating weight loss rate is less than 0.5%, the adhesive force between the epoxy resin coated on the copper foil and the ultraviolet curable resin is weak in the semi-cured laminate.

Therefore, when the heat curing treatment is performed, the epoxy resin is pulled along with the thermal expansion of the copper foil, so that peeling occurs between the epoxy resin and the ultraviolet curable resin, and the appearance of the copper foil appears as a bump. The appearance is poor. Further, if it exceeds 1.25%, heat curing becomes incomplete in a short time, and blistering occurs in the solder heat resistance test.

The semi-cured state of the epoxy resin applied and dried on one surface of the copper foil strip is adjusted to 0.5 to 1.25% by the weight reduction rate by heating at 200 ° C. for 20 minutes. In, the application of an epoxy resin to a copper foil strip, a method of adjusting the drying treatment conditions in the drying step can be adopted, for example, when using an epoxy resin (MA-2: Mitsui Mining & Smelting Co., Ltd.), The drying treatment may be performed at a temperature of 180 ° C. for 2 to 4 minutes.

On the other hand, under the temperature and time conditions of the heat curing treatment,
The heating temperature is 150 to 200 ° C. as described above. However, if the heating temperature is lower than 150 ° C., the curing of the epoxy resin will be insufficient and good solder heat resistance will not be obtained, and if the temperature exceeds 200 ° C., the copper foil surface will be oxidized. Adversely affect the soldering work in the component mounting process. On the other hand, the heating time is 20-4
It is performed for 0 minutes, but if it is less than 20 minutes, the adhesive strength between the copper foil and the epoxy resin is weak, and good solder heat resistance cannot be obtained, and heating for more than 40 minutes is useless.

According to the method for manufacturing a copper clad laminate for a printed wiring board according to the present invention, the heating furnace is continuously loaded in a single plate state without stacking the laminates by heat curing treatment. By putting it in and applying heat curing treatment for a short time,
A copper-clad laminate for a printed wiring board, which has a good appearance of copper foil and excellent adhesiveness and solder heat resistance, can be obtained.

[0020]

【Example】

[Example 1] An unsaturated polyester UV curable resin was applied on the upper surface of a steel strip to a thickness of 20 µm, and then UV rays (lamp output 160 W / cm, distance between lamp and steel strip 75) were applied.
mm) and then preheat this steel strip together with the coated UV curable resin (temperature 100 ° C.), then apply the UV curable resin and one side of the copper foil strip to a thickness of 30 μm, 180 ° C.
Drying for 3 minutes, so that the semi-cured state becomes 0.75% by the weight loss rate by heat treatment at 200 ° C. for 20 minutes.
The coated and dried epoxy resin (MA-2: manufactured by Mitsui Mining & Smelting Co., Ltd.) is heated on its resin surfaces (heating temperature: 150).
(° C).

Through the above steps, a laminated strip having a three-layer structure of steel strip, insulating resin and copper foil strip can be obtained. But in this state,
Since UV curable resin and epoxy resin are in a semi-cured state and both adhesiveness and solder heat resistance are insufficient, the laminated strip obtained in the above process is sheared to an appropriate size, and then the laminated plates are not stacked. , In the state of a single plate, it is continuously charged and passed through a heating furnace with an ambient temperature of 150 ° C (or 200 ° C) for 40 minutes (or 20 minutes). A cured copper-clad laminate for a printed wiring board was obtained.

Comparative Example 1 The epoxy resin applied to the copper foil strip of Example 1 was dried at 180 ° C. for 5 minutes, and the semi-cured state was heated at 200 ° C. for 20 minutes to reduce the weight by heating. Was adjusted to 0.25% and a copper clad laminate for printed wiring board was obtained in the same manner as in Example 1.

Comparative Example 2 The epoxy resin applied to the copper foil strip of Example 1 was dried at 180 ° C. for 1 minute, and the semi-cured state was heated at 200 ° C. for 20 minutes. Was adjusted to 1.75% and a copper clad laminate for printed wiring board was obtained in the same manner as in Example 1.

[Comparative Example 3] The epoxy resin applied to the copper foil strip of Example 1 was dried at 150 ° C for 3 minutes, and the semi-cured state was heated at 200 ° C for 20 minutes. To obtain 3.0%, then obtain a laminated plate with a three-layer structure of steel plate / insulating resin / copper foil, stack 60 laminated plates into a heating furnace, and set the ambient temperature to 150%. A copper-clad laminate for a printed wiring board, in which the ultraviolet curable resin and the epoxy resin were completely cured, was obtained by a heat curing treatment of passing through a heating furnace at a temperature of 4 ° C. for 4 hours. Various conditions of Example 1, Comparative Examples 1 and 2, and a test of the laminated plate obtained by the stacking heat curing treatment of Comparative Example 3 were conducted, and the results are shown in Table 1.

[0025]

[Table 1] Appearance of copper foil after curing ... After storage at room temperature for 24 hours, JIS C
The occurrence of bumps on the copper foil surface was observed in the evaluation of 6481, the score was determined according to the size, and the total score was evaluated. ○: 25 points or less in 250 mm square ×: 35 points or more in 250 mm square Peeling strength after soldering ... After storing at room temperature for 24 hours,
Float in a solder bath at 300 ° C for 20 seconds, then cool to room temperature and evaluate according to JIS C6481 peel strength measurement method. Soldering heat resistance: After storing at room temperature for 24 hours, float in a solder bath at 300 ° C for 20 seconds. After cooling to room temperature,
It was evaluated according to the solder heat resistance test method of IS C6481, and after being stored at room temperature for 24 hours, it was immersed in boiling distilled water for 60 minutes, and then in flowing clear water kept at a temperature of 20 ° C.
After cooling for 0 minutes, then floating in a solder bath at 300 ° C. for 20 seconds and then cooling to room temperature, evaluation is made according to the solder heat resistance test method of JIS C6481 x: swelling, peeling of interface

[0026]

EFFECTS OF THE INVENTION According to the present invention, a printed wiring having a good appearance of a copper foil, a bonding strength and a soldering heat resistance can be obtained by a heating and curing process for a short time without stacking and disassembling work before and after the heating and curing process. Copper-clad laminates for boards can be manufactured.

[Brief description of drawings]

FIG. 1 is an explanatory view of a method for manufacturing a copper-clad laminate for a printed wiring board according to the present invention.

FIG. 2 is a sectional structural view of a copper-clad laminate for a printed wiring board according to the present invention.

Claims (1)

[Claims] 1. A steel strip having a semi-cured UV-curable resin on one side thereof is preheated, and the semi-cured UV-curable resin and the epoxy resin in the semi-cured state are applied and dried on one side of a copper foil strip. And are pressed by a roll to form a laminated plate having a three-layer structure of a steel strip, an insulating resin made of an epoxy resin and an epoxy resin, and a copper foil strip, and the laminated strip having the three-layer structure is sheared to an appropriate size, Next, in the method for producing a copper-clad laminate for a printed wiring board, in which the laminate having the three-layer structure is heated in a heating furnace to completely cure the insulating resin, an epoxy resin coated and dried on one side of the copper foil strip is used. Set the semi-cured state of the resin to 20
The weight loss rate by heating at 0 ° C for 20 minutes is 0.5-
The temperature is adjusted to 1.25%, and the ambient temperature is 1 in a single plate state without stacking the above three-layer laminated plates.
A method for producing a copper-clad laminate for a printed wiring board, which comprises continuously charging in a heating furnace at 50 to 200 ° C. and heat-curing for 20 to 40 minutes in the furnace.