JP2002118345A - Production method for double layer flexible board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method for double layer flexible board, with which satisfactory production efficiency and quality can be achieved even when facilities are reduced and production costs are suppressed especially. SOLUTION: The surface of silver foil is speedily coated with a modified polyimide having a simple substance containing a bismaleimide functional group using a coater. After pretreatment drying and cyclization by placing the silver foil into a five-step oven, the semiproduct of a circuit board is taken up by a metal roller. Following that a product is completed by placing the semiproduct into a sealed nitrogen furnace for forcedly circulating cooling air around the semiproduct, heating and hardening it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a two-layer flexible substrate, which can achieve excellent production efficiency and quality even if the equipment is reduced and the production cost is reduced.

[0002]

2. Description of the Related Art Polyimide (Polyimimi)
de, hereinafter referred to as PI) material has unique and excellent physical and chemical properties, and since these properties include heat resistance, weather resistance, mechanical properties, electrical properties, insulation properties, etc., it is flexible. It is widely used as a material for a substrate (hereinafter, referred to as FPC).

However, PI is a metal substrate (for example, copper foil)
In most cases, the adhesive between the PI and the copper foil is adhered to the intermediate layer using an adhesive, because the adhesive is not suitable for the FPC under the high temperature environment of the FPC. The use performance is greatly reduced, and the manufacturing process becomes very complicated. Therefore, if the PI and the copper foil are directly bonded without using an adhesive, the heat resistance and electrical properties of the FPC can be greatly improved.

[0004] A conventional product using a method without using an adhesive will be described below. In Japanese Patent No. 2738453,
A method for manufacturing an FPC comprising a multi-layered PI film was described, and the PI film was successfully adhered to a copper foil by a multi-layer coating method. It is complicated and difficult to match the coefficient of thermal expansion (CTE). Therefore,
This method is not suitable for flattening the FPC and has poor size stability.

US Pat. No. 5,077,084 describes a production method utilizing a coating method, which comprises a polyamic acid (hereinafter referred to as PA) which is a precursor of a PI film.
A) is directly adhered onto the copper foil, and heated in a nitrogen furnace at 200 ° C. and 450 ° C., respectively.
Thereafter, the PI film is adhered onto the copper foil by performing drying and cyclization. However, in this method, although the oxygen amount in the nitrogen furnace is suppressed to less than 0.2%, the oxidation of the copper foil cannot be prevented by using this method, and the tension is reduced to 0.1 in order to obtain excellent flexibility. It needs to be controlled to 02 to 0.2 kg / cm ² .

US Pat. No. 5,518,779 describes a coating method for two-layer extrusion, which involves coating once on copper foil and then heating the copper foil in an infrared oven. To obtain a polyamic acid having excellent absorption and curing efficiency. However, in this method, a polyamic acid having an excellent cyclization ratio can be obtained by an infrared oven, and about 350
In an environment filled with nitrogen at a cyclization temperature of ° C., the curing time can be significantly reduced from the original 120 minutes to 20 minutes, but the capital investment is very high and the nitrogen furnace is open, When performing the hardening process continuously, it is necessary to keep replenishing nitrogen between processes,
Production costs are very high. Furthermore, since the nitrogen furnace is an open type, it takes a long time to heat and it is very difficult to control the amount of oxygen. Therefore, there is room for further improvement.

If the above-mentioned FPC is wound without using an open-type nitrogen furnace and then hardened by a closed-type nitrogen furnace with low equipment cost, the FPC semi-finished product becomes a PI. Due to the viscosity of the film, it adheres to the copper foil and may be damaged.

The present invention solves the above-mentioned problems, and comprises adding a chemical cyclizing agent to a modified polyimide, and further producing a two-layer flexible substrate from the polyimide to which the chemical cyclizing agent is added and a copper foil. After performing the curing process, winding and drying are performed to produce a semi-finished product of the two-layer flexible substrate, and the semi-finished product of the two-layer flexible substrate is placed in an oven of a closed-type nitrogen furnace, and finally cured and heated. The product is completed by performing the processing. Therefore, it is possible to achieve a method for manufacturing a two-layer flexible substrate with low equipment and manufacturing cost, high production efficiency, and excellent quality.

[0009]

According to the present invention, a modified polyimide having a simple substance containing a bismaleimide functional group is rapidly applied on a copper foil by a coater, and then heated in a five-stage oven, followed by pretreatment drying and drying. After processing, the semifinished product of the circuit board is wound up by a metal roller, and then put into a closed nitrogen furnace in which cooling air is forcibly convected in the surroundings, and the product is completed by heating and curing. A method for manufacturing a two-layer flexible substrate is provided.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a flowchart of a method for manufacturing a two-layer flexible substrate according to the present invention, and FIG. 2 is a perspective view of a semi-finished product of the method for manufacturing a two-layer flexible substrate according to the present invention.

The method for producing a two-layer flexible substrate according to the present invention is directed to a bismaleimide (bis) containing a chemical cyclizing agent.
By using a modified polyimide having a functional group-containing simple substance, a superior cyclization conversion is obtained, and a semi-finished product of a completely wound two-layer flexible substrate is manufactured, and the two-layer flexible substrate is manufactured. The semi-finished product is placed in a closed high-temperature nitrogen furnace for cyclization.
Also, the added chemical cyclizing agent is a tertiary amine (tertiamine).
ary amine) and an anhydride having a dehydrating action.

Among them, the acid anhydride having the best effect is acetic anhydride, and the amount added to the modified polyimide is 0.5 to 5.0 times the number of moles of imidic acid.

Also, low molecular weight fatty anhydrides (for example, propionic anhydride, butyric anhydride, and valeric anhydride) which are one or a mixture of two or more kinds other than acetic anhydride can be used.
Furthermore, they can achieve the same ring effect, the general formula _{(1) (C n H 2n} + 1) 2 C 2 O 3 ··· ( Formula 1) (wherein the fatty acid anhydride thereof, n Represents 1, 2, 3, or 4).

The tertiary amine in the chemical cyclizing agent can be represented by the following general formula (2): R ₃ N (Formula 2) (where R represents methyl or ethyl). . Further, tertiary amines having excellent effects include pyridine and betapicoline (beta).
-Picoline), trimethylamine (trime)
thylamine), triethylamine (triet)
hydramine), among which triethylamine has the most excellent effect, and the amount added to the modified polyimide is 0.5 to 5.0 times the number of moles of imide acid. In addition, trimethylamine has the best activity, so the amount added is slightly less than other tertiary amines.

An appropriate type of chemical cyclizing agent is added to the modified polyimide, and the mixture is stirred in an environment of 25 ° C. on average, and the obtained mixture is subjected to a bubble removing treatment by a vacuum pump. Coating on a copper foil on average. At that time, the tension is 0.02-0.2
kg / cm and the speed is controlled between 12 and 1.0 m / min. Then, the copper foil coated with the modified polyimide is dried and cyclized by a five-stage oven whose temperature is controlled at 100 to 200 ° C. Furthermore, after cyclizing the copper foil coated with the modified polyimide by the first heat treatment, the semi-finished product of the two-layer flexible substrate is wound,
It is placed in a closed-type nitrogen furnace and cured by the second heat treatment to complete the product of the two-layer flexible substrate. Also, when performing the above steps, be sure to keep the oxygen amount in the closed nitrogen furnace at less than 0.5% (preferably 0.2% or less) and the heating temperature at 250 to 400 ° C (preferably 30%).
(0 to 350 ° C.) and the heating time to 15 to 240 minutes (preferably 30 to 60 minutes).

A method for manufacturing a two-layer flexible substrate according to the present invention will be described with reference to FIG. After performing the modified polyimide production step (10) having bismaleimide,
After performing the chemical cyclizing agent addition step (11) to the modified polyimide, the stirring and the defoaming step (12) are performed, and the coating treatment step (13) is performed on the copper foil using a conventional coater. Next, the copper foil is subjected to a pre-treatment baking treatment step (14), and thereafter, a winding semi-finished product manufacturing step (15) is performed.
The semi-finished product is placed in a closed-type nitrogen furnace in which cooling air is forcibly convected around, and a curing process (16) is performed to complete the product.

As shown in FIG. 2, the semi-finished product of the two-layer flexible substrate according to the present invention utilizes a stainless steel rod (20), and the copper foil surface (21) faces the stainless steel rod (20).
Also, it is manufactured by winding so that the polyimide surface (22) is on the outside.

Also, in some embodiments of the present invention, 90
° Peel strength (peel strength), tensile strength (tensile strength), elongation (el
engagement:%) and the degree of flexure (degree o)
f curl) was measured, the 90 ° peel strength was measured according to IPC TM650-2,4,9, the tensile strength was measured according to IPC TM650-2,4,9, and the degree of flexure was measured. Is a semi-finished product of a two-layer flexible substrate cut into a width of 50 mm and a width of 5 mm, and the both ends are wound up and pulled. The distance between the ends is used as a reference standard value for winding.

Hereinafter, each embodiment will be described.

EXAMPLE 1 A chemical cyclizing agent was added to a modified polyimide having bismaleimide, and triethylamine and acetic anhydride were used as the chemical cyclizing agent. The molar ratio of imidic acid in the triethylamine and the modified polyimide is 0.5 to 5.
The ratio of acetic anhydride to the number of moles of imide acid in the modified polyimide is 0.5 to 5.0. Thus, the molar ratio of triethylamine to acetic anhydride is 1: 1. Further, after sufficiently agitating the modified polyimide to which the chemical cyclizing agent was added, deaerated by a vacuum pump, and quickly coated on a 1/2 oz electrolytic copper foil using a conventional coater to form a 200 μm Is formed, and the copper foil of the wet film is initially dried and cyclized in a five-stage heating oven at a temperature of 100 ° C to 200 ° C. The coating speed of the coater is controlled to 12.0 to 1.0 m / min, and the tension is controlled to 0.02 to 0.2 kg / cm.

In the method shown in FIG. 2, a semi-finished product of a two-layer flexible substrate is wound, and the semi-finished product is placed in a closed nitrogen furnace in which cooling air is forcibly convected around the semi-finished product. At that time, the amount of oxygen in the nitrogen furnace was less than 0.5%, and the heating temperature was 250%.
４５０450 ° C., and the heating time is 15〜240 minutes.
Thereafter, cooling air is forcibly convected around the nitrogen furnace to lower the temperature from 300 to 350 ° C. to room temperature to complete the product. The time required for lowering the temperature is 30.
~ 60 minutes.

The contents of the measurement results of each physical characteristic shown in Table 1 of FIG. 3 will be described below.

Embodiment 2 The 工程 ounce electrolytic copper foil in the first embodiment is changed to a オ ン ounce pressed copper foil, and the manufacturing process is the same as that of the first embodiment.

Example 3 No chemical cyclizing agent was added to the modified polyimide, the set temperature of the nitrogen furnace was 350 to 400 ° C., and the heating time was 60 minutes.

[Comparative Example] The components of the coating and the copper foil in the comparative example are the same as those in Example 3, but the copper foil coated with the modified polyimide was dried 30 cm ×
It is cut to a size of 30 cm and cured in a conventional closed nitrogen oven without forced convection of cooling air around it. Hereinafter, the conditions of the curing treatment step will be described. Room temperature to 150 ° C: 30 minutes (vacuum) 150 ° C constant temperature: 30 minutes (vacuum) 150 ° C to 250 ° C: 30 minutes (vacuum) 250 ° C constant temperature: 30 minutes (vacuum) 250 ° C to 350 ° C: 30 minutes (vacuum) 350 ° C constant temperature: 60 minutes (vacuum) 350 ° C to room temperature: 210 minutes (vacuum)

[0023]

According to the present invention, a two-layer flexible substrate is produced by adding a chemical cyclizing agent to a modified polyimide, further producing a polyimide containing the chemical cyclizing agent and a copper foil, and performing a curing treatment. Then, the semi-finished product of the two-layer flexible substrate is manufactured by winding and drying, and the two-layer flexible substrate is placed in an oven of a closed type nitrogen furnace, and finally, a product is completed by performing a curing heat treatment. Therefore,
It is possible to achieve a method for manufacturing a two-layer flexible substrate with low equipment and manufacturing cost, high production efficiency, and excellent quality.

[Brief description of the drawings]

FIG. 1 is a flowchart of a method for manufacturing a two-layer flexible substrate according to the present invention.

FIG. 2 is a perspective view of a semi-finished product of the method for manufacturing a two-layer flexible substrate according to the present invention.

FIG. 3 shows a comparison table 1 of physical properties of a two-layer flexible substrate made of different types of copper foils according to the present invention.

FIG. 4 is a table showing a comparison table 2 between the manufacturing method of the present invention and a conventional manufacturing method.

[Explanation of symbols]

Reference Signs List 10 Manufacturing process of modified polyimide 11 Addition of chemical cyclizing agent 12 Stirring and defoaming process 13 Coating process 14 Pretreatment baking process 15 Manufacturing process of wound semi-finished product 16 Hardening process 20 Stainless steel rod 21 Copper foil surface 22 Polyimide surface

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Natsu Kunio, No. 36, No. 36, Rinkouri-ri, Shinrin-ri, Minami-ku, Taichung, Taiwan No. 9 (72) Inventor Lin Juraku 13, Yongkang, Fukuzuri, Da'an-ku, Taipei, Taiwan 13 Street No. 16-2 No. (72) Inventor Li Jianhui, No. 27, No. 20, No. 487 Street, No. 27, Ninghe River, Jiandong-ri, Zhudong Township, Hsinchu County, Taiwan 4F100 AB17B AB33B AH02A AH03A AK49A AL06A BA02 EH462 EJ082 EJ422 EJ60 EJ862 EJ942 GB43 JL02 4J043 PA15 PA19 PB03 RA35 YA08 YB19 YB25 YB32 ZB50

Claims (4)

[Claims] 1. A modified polyimide having a simple substance containing a bismaleimide functional group is rapidly applied on a copper foil by a coater, placed in a five-stage oven and heated to perform pretreatment drying and cyclization. The semi-finished product of the circuit board is wound by a metal roller, and then the product is completed by heating and curing in a closed nitrogen furnace in which cooling air is forcibly convected around. Method for manufacturing a layer flexible substrate. 2. A modified polyimide comprising a chemical cyclizing agent comprising a tertiary amine and an acid anhydride having a dehydrating action, wherein the acid anhydride is a low molecular weight fatty acid anhydride. Formula (1) (C _n H _{2n + 1} ) ₂ C ₂ O ₃ (Formula 1) (wherein n represents 1, 2, 3 or 4), and a tertiary amine The two-layer flexible substrate according to claim 1, characterized by being represented by the following general formula (2): R ₃ N (Formula 2) (where R represents methyl or ethyl). Manufacturing method. 3. The coater tension is 0.02-0.2k.
g / cm, the speed is controlled from 12 to 1.0 m / min, the temperature range of the five-stage oven is 100 ° C. to 200 ° C., the oxygen amount of the closed nitrogen furnace is controlled to less than 0.5%, Further, preferably, the amount of oxygen is 0.2% or less, the heating temperature is 300 to 350C, and the heating time is 15 to 60 minutes. A method for manufacturing a flexible substrate. 4. The addition amount of the fatty anhydride is about 0.5 to 5 times the number of moles of imidic acid, and the addition amount of the tertiary amine is about 0.5 to 5 times the number of moles of imidic acid. Characterized by
A method for manufacturing a two-layer flexible substrate according to claim 2.