JPH0818196A - Manufacture of flexible printed wiring board - Google Patents

Abstract

PURPOSE:To realize a high performance flawless flexible printed wiring board having no surface defect by repeating a roll surface cleaning operation for passing a viscous film through the board film and metal foil pass line in a coater laminator. CONSTITUTION:A viscous roll 3 having cleaned surface is installed in a coater laminator 1 and a viscous film is fed from a board film feeding section 2 through a film pass line while a same kind of viscous film is fed tram a metal foil feeding section 12 through the film passline. A polyimide film is then coated, through a roll coater 4, with an epoxy/NBR based adhesive 5 and passed through an inline drier 8 where the solvent is removed and the adhesive is semi-cured before the polyimide film and an electrolytic copper foil are hot pressed. When a both-sided product thus produced is thermally hardened in a cure oven, foreign matters can be removed through combination of viscous roll and viscous film or through periodic running of viscous film thus realizing a board having good surface conditions stably.

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 high-performance flexible printed wiring board which is free from scratches, foreign matter, bubbles, etc. on the metal foil surface, adhesive layer and substrate film surface used for flexible printed circuits and the like. It is about.

[0002]

2. Description of the Related Art Recently, weight reduction of electronic products,
Demand for printed circuit boards has increased due to thinning and higher functionality,
Above all, the range of use of flexible printed circuits has expanded,
The demand is increasing more and more. In recent years, as printed circuit performance has become higher, finer patterns, thinner and more multilayered, scratches such as dents, wrinkles, and scratches on the surface of the metal foil on the substrate surface, and small scratches on the film surface. Even small defects such as surface defects such as foreign substances in the adhesive layer and generation of air bubbles lead to circuit defects as the circuit width becomes narrower and finer patterns are formed, and therefore improvement is required. The following items can be considered as the causes of the occurrence of these surface defects and the inclusion of foreign matter. 1) Foreign substances originally present in the raw materials (substrate film, metal foil, adhesive) are mixed. 2) In the process of manufacturing a flexible printed circuit board using a coater laminator, scratches are likely to occur due to the inclusion of foreign matter from various rolls in contact with the film or metal foil. 3) In the curing step, scratches and dents are formed on the metal surface due to the inclusion of foreign matter existing in an apparatus such as an oven. Further, if foreign matter is mixed in from the laminator, the foreign matter will be pressed against the metal foil-attached surface and distorted, and it will be cured while holding the dent. 4) Foreign matter is mixed in in the slit process, the packaging process, and the like. This often causes contact between the product substrate and a cutter, a roll, or the like, which causes a surface defect such as a dent or a wrinkle on the surface of the metal foil.

[0003]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned drawbacks and to provide a method for producing a high-performance flexible printed wiring board which has few surface defects and retains its original performance without damage. is there.

[0004]

Means for Solving the Problems The inventors of the present invention have made earnest studies on prevention of contamination of foreign matters in order to solve the above-mentioned problems, and as a result have arrived at the present invention. The invention of No. 1 uses a coater laminator to coat and dry an adhesive on a substrate film, and then manufactures a flexible printed wiring board laminated by pressure bonding with a metal foil. As the surface cleaning operation, after passing the adhesive film through the substrate film and the metal foil pass line of the coater laminator, the main operation is started, and the roll surface cleaning operation is performed after a predetermined time has elapsed after the start of the main operation. Is one cycle, and the cycle is repeatedly operated, a method for manufacturing a flexible printed wiring board, the second invention is the manufacturing method of the first invention,
An adhesive roll coated with an adhesive rubber is used as a drive roll in contact with a substrate film and a metal foil pass line substrate film and a metal foil, and a coater laminator installed on a supporting free roll, and after the roll surface cleaning operation, A method for manufacturing a flexible printed wiring board is characterized by performing a main operation.

The present invention will be described in detail below. The adhesive film having adhesiveness used in the present invention is passed through a pass line of a coater laminator, a substrate film, and a metal foil are brought into contact with a roll of a device in contact with the roll surface to remove foreign matter, dirt, and the like. Those satisfying the following conditions are desirable. 1) It has an adhesive force to remove foreign matter and dirt from a roll and holds it, and can pass through a substrate film pass line of a coater laminator. 2) It is preferable that the pressure-sensitive adhesive component is not transferred to the device, and in consideration of the above item 1), the pressure-sensitive adhesive force is preferably 20 to 100 g / 25 mm. If it is less than 20 g / 25 mm, the foreign matter does not adhere to the adhesive film, and the foreign matter remains on the substrate film and the metal foil pass line. If it exceeds 100 g / 25 mm, the adhesive will stick to the roll too much, and the running property of the adhesive film will deteriorate. Further, since the adhesive film is passed through the equipment, it is necessary to withstand the driving tension of the equipment, and a support film coated with an adhesive layer is preferable. For example, polyester film, PP film, P
PS film, PVC film (thickness 10 to 100 μm), etc. coated with adhesive component on one side or both sides (Adhesive layer 2
-30 μm) is preferred. The film width is preferably wider than the width of the flexible printed board to be manufactured and within the width of the device.

The adhesive roll coated with the adhesive rubber, which is installed on the substrate film pass line of the coater laminator used in the present invention, includes a substrate film and a foreign substance attached to the surface of the metal foil when the adhesive roll contacts the adhesive film. It removes dirt and the like, and it is desirable that it satisfies the following conditions. 1) It has an adhesive force for removing foreign matter and dirt from the surface of the substrate film and the metal foil and holding it, and is capable of running the substrate film and the metal foil. 2) It is preferable that the pressure-sensitive adhesive component does not transfer to a device, and acrylic or urethane rubber having adhesiveness is preferable. The adhesive strength of the adhesive is preferably 20 to 100 g / 25 mm,
If it is less than 20 g / 25 mm, foreign matter cannot be removed from the substrate film or the metal foil, and if it exceeds 100 g / 25 mm, the substrate film or the metal foil adheres to the adhesive roll and the traveling cannot be performed. If foreign matter or dirt adheres to the entire surface of the roll, the adhesive strength will be lost.Before starting the operation or predicting roll dirt, wash the surface of the roll with water or an organic solvent that does not reduce the adhesive strength early so that the roll surface can be cleaned. is important. The roll width is wider than the width of the flexible printed board to be manufactured, and is preferably within the width of the equipment. The roll diameter may be any as long as it does not cause a problem in running the film, and generally 100 to 300 mmφ is preferable.

The installation position of the adhesive roll may be any film path line in contact with the substrate film and the metal foil. Generally, it is immediately after the substrate film feeding roll, before the adhesive coating roll, or after the laminating roll. Before is preferable,
Also for the metal foil, a period immediately after the feeding roll and before the laminating roll is preferable. Further, the roll may be a driving roll or a supporting free roll, and a roll that is in efficient contact with the substrate film or the metal foil surface is preferable. An example of the arrangement of the adhesive roll is shown in FIG.

The apparatus for producing a flexible printed wiring board used in the present invention is one in which a heat resistant substrate film and a metal foil are bonded together via an adhesive, and a coater laminator for dry lamination is preferable, and basically 1 )
Substrate film feeding part, 2) adhesive coater, 3) dryer, 4) laminator, 5) metal foil feeding part, 6) product winding part, each part is a film driving roll, a supporting roll, a coater roll It is composed of many rolls such as a laminating roll (nip roll). When foreign matter adheres to the roll surface or the like of the above-mentioned device, the foreign matter is mixed in the product or the foreign matter pushes the substrate film or the metal foil surface on the roll surface. It leads to the generation of scars. FIG. 1 shows an example of the coater laminator used in the present invention. Here, the substrate film pass line is a line extending from the substrate film feeding unit 2 to the coater 4 to the dryer 8 to the laminator 9 to the product winding unit 13, and the metal foil pass line is the metal foil feeding unit 12 → Laminator → The line that reaches the product winding section 13. As an example of the installation location of the adhesive roll of the present invention, as shown in FIG. 1, two rolls (driving roll and free roll) are installed after the substrate film feeding section 2 to clean the two front and back surfaces of the substrate film, and the metal foil. After the feeding unit 12, two rolls (driving roll and free roll) are installed to clean the front and back surfaces of the metal foil.

According to a first aspect of the invention, prior to the main operation, the adhesive film is passed through a substrate film and a metal foil pass line to clean the roller surface of the pass line, and then an adhesive is applied to the substrate film in the main operation. It is processed and dried, then pressure-bonded and laminated with a metal foil to produce a flexible printed circuit board,
Further, the roll surface cleaning operation in which the adhesive film is passed through the entire length of the substrate film and the metal foil pass line is set as one cycle every predetermined time after the start of the main operation, and the cycle is repeated. Here, the predetermined time of the main operation depends on the installation environment of the coater laminator, the operating time of the equipment, and the like, but is about 3500 to 4500 m after being manufactured as a double-sided product. A second invention is a combination of a method for cleaning the two front and back surfaces of a substrate film with a coater laminator equipped with the above-mentioned adhesive roll and a method for cleaning by traveling an adhesive film, the latter being before the start of manufacturing a substrate for a flexible printed circuit. The above adhesive film is passed through a substrate film pass line of a coater laminator and a metal foil pass line for 5 to 100 m at a line speed of 1 to 10 m / min., And the substrate film and the metal foil are brought into contact with the adhesive layer of the adhesive film. Clean the roll surface. After that, the substrate film is run, an adhesive is applied to the film, dried, and then pressure-bonded with a metal foil to manufacture a flexible printed wiring substrate.

Next, a method for manufacturing a flexible printed wiring board will be described. Basically, a heat-resistant plastic film is used as a substrate film and a metal foil is laminated on the substrate film via an adhesive, but the heat-resistant plastic film used here has electrical insulation,
These include polyimide, polyphenylene sulfide, polyparabanic acid, polyester, polyether sulfone, polyether ale ketone, and other films,
A thickness of 12.5 to 125 μm is used. The thermosetting heat-resistant adhesive used here is epoxy resin, NBR / phenolic resin, phenol / butyral resin, epoxy / NBR resin, epoxy / phenolic resin, epoxy / nylon resin, Epoxy / polyester type resin, epoxy / acrylic type resin, polyamide / epoxyphenol type resin, polyimide type resin, acrylic type resin and silicone type resin are exemplified, and the thickness of the adhesive at the time of lamination is 5 to 30 μm in a dry state. preferable.

Examples of the metal foil include copper foil, aluminum foil, iron foil, nickel foil and the like. As the printed circuit, copper foil is preferable, and rolled copper foil and electrolytic copper foil having a thickness of 18 to 70 μm are used. It The method of laminating the substrate film and the metal foil is in accordance with a conventional method, in which a substrate film is coated with a thermosetting adhesive by a roll coater or the like, and an in-line dryer is used to evaporate and remove the solvent (organic solvent such as MEK, toluene and methanol). It is semi-cured and is continuously thermocompression-bonded to the metal foil by a heated heat roll. Temperature is 60-150 ℃, linear pressure is 5
-30kg / cm and line speed 1-10m / min. Are standard.
The flexible printed wiring board thus laminated is further cured by heating in a curing oven at 80 to 200 ° C for 1 to several tens of hours in order to complete the thermosetting of the adhesive and improve the physical properties of the substrate. To do.

[0012]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited thereto. [Evaluation method of flexible printed wiring board] 1) Surface inspection: The front and back of the flexible printed wiring board are passed through an inspector at a speed of 1 m / min. And visually inspected. (Evaluation symbol) Number of dents and wrinkles (0.2 mmφ or more) / Laminate board
100 m ◎; 0-5 pcs / 100 m, ◯; 6-10 pcs / 100 m △; 11-40 pcs / 100 m, ×; 40 pcs / 100 m or more 2) Inspection of adhesive layer: flexible metal-clad 4 laminated boards
Cut to 80 x 240 mm, remove metal by etching, wash with water, dry, and visually inspect the adhesive layer with a 20x magnifying glass to determine the number of bubbles and foreign matter of 0.2 mmφ or more. (Evaluation symbol) Number of bubbles and foreign matter ◎; None, ○: 1, △: 2, ×: 3 or more

(Examples 1 to 3) An adhesive roll whose surface was cleaned with water or ethanol shown in Table 1 was installed in a coater laminator having the following specifications, and the width was 600 mm and the thickness was 65 μm.
An m × 100 m adhesive film was passed through the film pass line from the substrate film feeding portion at a line speed of 3 m / min. On the other hand, 50 m of the same kind of adhesive film was passed through the film pass line at a line speed of 3 m / min. Next, as a substrate film, 25 μm thick,
Epoxy / NBR adhesive is applied to a 508 mm wide polyimide film with a roll coater so that the thickness after drying will be 18 μm, and the solvent (ME
K) is removed to make the adhesive semi-cured, and then 18 μm electrolytic copper foil is heated to a heating roll temperature of 120 ° C., linear pressure of 20 kg / cm, 3 m /
A single-sided product was manufactured by thermocompression bonding at a line speed of min. and winding into a roll, and then the single-sided product was counter-rotated and the double-sided product was manufactured through the above steps again. This was further heat-cured in a curing oven at 80 ° C for 5 hours and 150 ° C for 5 hours to prepare a substrate for flexible printed wiring. Then, it was passed through the inspector at a speed of 1 m / min., And two people visually inspected the front and back. Separately, the adhesive layer was also inspected by etching.

Specifications of coater laminator 1) Machine width (roll width): 650 mm, 2) Reverse roll coater: 3 reverse rolls, 3) Dryer: arched roll support, 4) Laminator: heated metal roll 350 mmφ, 5) Substrate winding unit for flexible printed wiring: Biaxial turret, 6) Roll: There are about 50 rolls in the device. (Diameter
(100, 200, 350 mmφ, etc.) 7) Adhesive roll: As shown in the schematic diagram of the coater laminator in FIG. 1, two 120 mmφ × 650 mmL rolls were installed after the substrate film feeding part and the metal foil feeding part. This adhesive roll is called "New Tuck Roll (trade name)" manufactured by Shin Toselo Sangyo Co., Ltd. The adhesive is a urethane elastomer wound in a thickness of 5 mm, and the adhesion is # 110.
˜130 (based on JIS K 6301 spring test type A, hardness # 110 = 10, # 120 = 20, # 130 = 30). 8) Adhesive film: "Sticky Roll" (trade name, manufactured by Mitsubishi Rayon Co., Ltd.) having an acrylic rubber adhesive layer and an adhesive force of Table 1 was used.

(Comparative Example 1) A double-sided product was manufactured in the same manner as in Example 1 except that an adhesive roll and an adhesive film were not used, the surface was inspected, and the adhesive layer from which the metal foil was removed by etching was inspected. did. The results are shown in Table 1.

(Comparative Example 2) When no adhesive roll was used in Example 1 and an adhesive film having an adhesive force of 150 g / 25 mm was passed through, the adhesive force of the coater laminator to the roll was high and the film tension was high. However, the peeling from the roll was insufficient and the roll was entangled with the roll, causing breakage of the adhesive film and the like, and cleaning and running with the adhesive film on the film pass line could not be performed.

[0017]

[Table 1]

(Example 4) In the same manner as in Example 1, two adhesive rolls (# 120 adhesive strength hardness 20) were installed in each of the coater laminator after the substrate film feeding part and after the metal foil feeding part, and two substrate films were provided. , Both sides of the metal foil are in contact with each other, and an adhesive film having an adhesive force of 30 g / 25 mm is passed through the substrate film path line in advance at a line speed of 3 m / min.
It was manufactured at 00m. The surface inspection was conducted every 1000 m from the start of manufacturing. Table 2 shows the results.

Comparative Example 3 A double-sided product was prepared in the same manner as in Example 1 except that the adhesive film and the adhesive roll were not used.
It was manufactured for 5000 m, and inspected for each 500 m manufacturing unit, and the defect occurrence situation was investigated and shown in Table 2.

(Comparative Example 4) Similar to Example 4 except that the adhesive roll was not used, first, an adhesive film having an adhesive force of 30 g / 25 mm was first passed through a film pass line for 50 m, and then a double-sided product was continuously produced for 5000 m. . The test results are shown in Table 2.

[0021]

[Table 2]

(Examples 5 to 7) Using a coater laminator having the same specifications as in Example 1, a width of 600 mm and a thickness of 65 shown in Table 3 are used.
The μm × 100 m adhesive film was passed through the film pass line from the substrate film feeding portion at a line speed of 3 m / min. On the other hand, the same type of film 50
m was passed through the film pass line at a line speed of 3 m / min. Next, as a substrate film, thickness 25 μm, width 50
Epoxy / NBR on 8mm x 500mL polyimide film
18 μm after applying the system adhesive with a roll coater so that the thickness after drying is 18 μm and removing the solvent (MEK) through an in-line dryer to semi-cure the adhesive.
With the electrolytic copper foil, heating roll temperature 120 ℃, linear pressure 20kg / cm, 3
A single-sided product was manufactured by heating and pressing at a line speed of m / min. and winding on a roll, and then the single-sided product was counter-rotated and the double-sided product was manufactured again through the above steps. This was further heat-cured in a curing oven at 80 ° C for 5 hours and 150 ° C for 5 hours to prepare a substrate for flexible printed wiring. Next, the cloth was first passed through an inspector at a speed of 1 m / min., And two people visually inspected the front and back. Separately, the adhesive layer was also inspected by etching. Then the adhesive film (width 600mm
The thickness of 65 μm × 100 m) was cleaned from the substrate film feeding section through the substrate film pass line at a line speed of 3 m / min. Subsequently, a double-sided product was manufactured for 500 m in the same manner as above. This substrate film line cleaning and double-sided product production were repeated 10 times to produce 5000 m. The inspection was carried out every 500 m or 1000 m, and the results are shown in Table 3.

[0023]

[Table 3]

[0024]

EFFECTS OF THE INVENTION According to the present invention, even if foreign matter is mixed in from the raw material of a coater laminator, equipment, etc., it can be removed by the combined use of an adhesive roll and an adhesive film or the cyclic running of an adhesive film, and a scratch It is possible to continuously and stably manufacture a flexible printed wiring board with a good surface condition with few dents, dents, scratches, scratches, bubbles, etc., support for fine patterning, circuit production stage The utilization value is extremely high in the industry, such as the improvement of the yield in the industry.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of a coater laminator used in Example 1 of the present invention.

FIG. 2 is an explanatory diagram showing an example of a coater laminator used in Example 5 of the present invention.

[Explanation of reference numerals] 1 coater laminator 2 substrate film feeding section 3 adhesive roll (for driving, free) 4 reverse roll coater 5 adhesive 6 doctor knife 7 rubber roll 8 dryer 9 laminator 10 heating metal roll 11 cooling metal Roll 12 Metal foil feeding section 13 Flexible printed wiring board (single-sided product) winding section

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koichi Kuroda No. 1 Towada, Kamisu-cho, Kashima-gun, Ibaraki Prefecture Shin-Etsu Chemical Co., Ltd.

Claims (2)

[Claims] 1. In a main operation for producing a flexible printed wiring board in which an adhesive is applied to a substrate film by using a coater laminator and then dried, and then laminated with a metal foil by pressure bonding, in advance of the main operation. As the roll surface cleaning operation, after passing the adhesive film through the substrate film and the metal foil pass line of the coater laminator, the main operation is started, and after a predetermined time has elapsed after the start of the main operation, the roll surface cleaning operation is performed. The above is defined as one cycle, and the cycle is repeatedly operated, and a method for manufacturing a flexible printed wiring board. 2. The manufacturing method according to claim 1, wherein the adhesive roll coated with an adhesive rubber is installed on a substrate film and a drive roll and a supporting free roll in contact with the substrate film and the metal foil of a metal foil pass line. A method for producing a substrate for flexible printed wiring, which comprises using a coater laminator and performing the main operation after the roll surface cleaning operation.