JP2002344115A - Method of forming film and method of manufacturing printed board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the quality of a formed aluminum film from changing by moisture, an unreacted monomer, a solvent, an additive, etc., evaporated or scattered from an adhesive or flexible printed board to which the aluminum film is stuck with adhesive at the time of forming a metallic film on the printed board by sputtering, vapor deposition, etc. SOLUTION: The scattering of the moisture, unreacted monomer, solvent, etc., is prevented by covering the scattering sources of the moisture, monomer, solvent, etc., with masks 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a metal thin film on a flexible printed board and a method for manufacturing the flexible printed board.

[0002]

2. Description of the Related Art A conventional film forming method, in particular, a method of forming a metal film such as aluminum, a ceramic thin film or the like in a predetermined pattern on a flexible printed circuit board, first comprises a contact having an opening for film formation. The mold mask was placed at a predetermined position on the substrate. Thereafter, a film is formed on the flexible substrate by sputtering, vapor deposition, or the like.

[0003]

However, when a metal film is formed by sputtering or vapor deposition on a flexible printed circuit board bonded with an adhesive or the like in the above-mentioned conventional method, however, the moisture from the adhesive or the substrate is lost. The film quality of the formed aluminum may change due to evaporation and scattering of unreacted monomers, solvents, additives, and the like.
In some cases, problems such as a decrease in conduction resistance, a change in surface resistance, and darkening may occur.

The present invention solves the above-mentioned conventional problems. When a metal film is formed by sputtering or vapor deposition on a flexible printed circuit board bonded with an adhesive or the like, moisture or water from the adhesive or the board is reduced. An object of the present invention is to prevent the unreacted monomer and additives from evaporating and scattering, and to provide a high-quality thin film pattern.

[0005]

According to the present invention, there is provided a flexible printed circuit board bonded with an adhesive, comprising a member for inhibiting air flow around a film forming opening. A metal film is formed on the substrate by installing the formed mask, and is characterized in that scattering of moisture, unreacted monomers, and solvents during film formation is prevented.

Further, a mask is provided on a flexible printed circuit board mounted on a base having a convex curved surface and bonded with an adhesive, and the substrate surface and the mask are fixed by a member having a spring property. Is pressed to form a metal film on the substrate, thereby improving the film formation quality.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a film forming method according to an embodiment of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a sectional view showing a process of a film forming method according to a first embodiment of the present invention and an enlarged view thereof. In FIG. 1, 1 is a flexible printed circuit board, 2
Is an adhesive, 3 is a coverlay polyimide, 4 is a metal mask for film formation, 5 is a film-formed aluminum, 6 is aluminum which is sputtered, 10 is a hole, 7 is water scattered and evaporated from the hole 10 and evaporated water. , Unreacted monomer, 8 is a member formed on the mask that inhibits ventilation, 9 is an opening, 11 is a substrate holding base, and 12 is a mask opening.

The aluminum film forming method configured as described above will be described below with reference to FIG.

A coverlay polyimide 3 is adhered to a flexible printed circuit board 1 on which a circuit pattern is formed with an adhesive 2 for insulation and protection. The flexible printed board 1 is placed on a base 11, a mask 4 on which a film forming pattern is formed is placed on the flexible printed board 1, and the flexible printed board 1 is put into a sputtering apparatus (not shown).

Next, aluminum 6 is sputtered after the pressure is reduced. At this time, if the curing of the cover lay adhesive 2 is insufficient or the amount of water absorption is large, the opening 9 or the hole 1
From 0, water and unreacted monomer 7 (including solvent) are scattered.
However, since the mask 4 is formed with the member 8 that inhibits airflow, the amount of moisture and unreacted monomer 7 scattered from the mask opening 12 is reduced. Increase, discoloration, etc.) do not occur.

As described above, according to the present embodiment, a member that inhibits airflow is formed on a mask for forming a film by sputtering, vapor deposition, or the like on a printed circuit board that has been bonded with an adhesive. Aluminum), the curing of the coverlay adhesive 2 is insufficient,
Even when the amount of water absorption is large, a film with good quality can be formed.

FIG. 2 is a sectional view showing a process of a film forming method according to a second embodiment of the present invention. Embodiment 1
Portions having the same operation as those described above are denoted by the same reference numerals.
Reference numeral 13 denotes a plate material for pressing the mask 4, and reference numeral 14 denotes a vector indicating a pressing direction.

The process of the aluminum film forming method configured as described above will be described below with reference to FIG.

A polyimide coverlay 3 is adhered to a flexible printed circuit board 1 on which a circuit pattern is formed by an adhesive 2 for insulation and protection.
The flexible printed board 1 is placed on the base 11, a mask on which a film forming pattern is formed is placed on the flexible printed board, and the flexible printed board 1 is put into a sputtering apparatus (not shown).

Next, the aluminum 6 is sputtered after the pressure is reduced. At this time, the amount of moisture and unreacted monomer scattered from the mask opening 12 is reduced due to the formation of the member 8 which inhibits the ventilation in the mask 4. However, if the flexible printed circuit board is deformed, the flexible printed circuit board 3
There is a case where a gap is formed between the member and the member 8 and minute scattering occurs. Therefore, the amount of scattering can be extremely reduced by pressing the mask 4 downward from above the mask 4 with the pressing plate member 14, and no trouble (increase in conduction resistance, discoloration, etc.) occurs in the deposited aluminum. .

FIG. 3 is a perspective view showing a film forming method according to a third embodiment of the present invention. In FIG. 3, reference numeral 20 denotes a base for holding a flexible printed board, reference numeral 21 denotes a metal mask for film formation on which a member that inhibits airflow with the board surface is formed, reference numeral 22 denotes a flexible printed board, reference numeral 23 denotes a fixing jig having spring properties, Reference numeral 24 denotes an opening of the metal mask.

Flexible printed circuit board holding base 20
A flexible printed circuit board 22 on which an aluminum film is formed is disposed thereon, and a metal mask 21 on which a member that inhibits ventilation is formed is placed thereon. And the member 23 having a spring property
The mask, the flexible printed circuit board and the base are brought into close contact with each other. Thereafter, aluminum is formed by a sputtering apparatus. The adhesion between the substrate that inhibits airflow formed on the metal mask 21 and the substrate is increased by the pressing of the spring, and the amount of moisture and unreacted monomer scattered from the substrate is reduced. Therefore, no trouble (increase in conduction resistance, discoloration, etc.) does not occur in the deposited aluminum.

FIG. 4 is a perspective view showing a film forming method according to a fourth embodiment of the present invention. In FIG. 4, reference numeral 30 denotes a flexible printed circuit board holding base having a curved holding surface, 31 denotes a metal mask for film formation, 32 denotes a flexible printed circuit board, 33 denotes a fixing jig having spring properties, and 34 denotes an opening of the metal mask. It is.

Since the holding base 30 has a curved surface, the flexible printed circuit board 3 is pressed by the fixing jig 33.
The overall adhesion between the mask 2 and the mask 31 is improved. Therefore, even for a flexible printed circuit board having undulations, the adhesiveness with the mask can be enhanced, ventilation can be inhibited, and the scattering of moisture, unreacted monomers, etc. is reduced,
Defects such as a decrease in conduction resistance and discoloration do not occur, and the film formation quality can be improved.

FIG. 5 is a view showing a film forming method according to a fifth embodiment of the present invention. In FIG. 5, reference numeral 40 denotes a flexible printed circuit board holding base having a curved holding surface;
41 is a metal mask for film formation, 42 is a flexible printed board, 43 is a fixing jig having a spring property, 44 is an opening of the metal mask, 45 is a member that inhibits airflow, 46 is a hole formed in the flexible printed board. Department.

Since the holding base 40 has a curved surface, the flexible printed circuit board 4 is pressed by the fixing jig 43.
2 and the mask 41 are improved in overall adhesion (uniform adhesion), and mainly the holes 46 in the flexible printed circuit board 42.
The amount of scattered moisture and unreacted monomer is reduced. Further, since the member 45 that inhibits ventilation is formed around the opening of the mask 41, the effect of sealing moisture and unreacted monomers is enhanced. Therefore, no problem (such as an increase in conduction resistance or discoloration) occurs in the aluminum film formed in the pattern of the opening portion 44 of the mask 41, and the edge shape of the pattern becomes good.

FIG. 6 is a view showing an aluminum film forming mask according to the embodiment of the present invention. In FIG. 7, reference numeral 60 denotes a mask on which a member 62 that inhibits ventilation is formed, and 61 denotes a mask opening.

Since the member 62 for preventing airflow from the substrate surface is formed around the mask opening 61, the conductive resistance is low, the external resistance is not affected by the moisture and unreacted monomer scattered from the flexible printed circuit board. Also, a good aluminum pattern can be formed.

[0025]

As described above, according to the present invention, a mask for forming a film by sputtering, vapor deposition or the like on a flexible printed circuit board bonded with an adhesive is used to prevent airflow from the substrate surface. Forming a metal (aluminum)
By forming a film, it is possible to form a film of good quality even when the adhesive for the coverlay is insufficiently cured or the amount of water absorption is large.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a process of a film forming method according to a first embodiment of the present invention and an enlarged view thereof.

FIG. 2 is a sectional view showing a process of a film forming method according to a second embodiment of the present invention.

FIG. 3 is a perspective view showing a process of a film forming method according to a third embodiment of the present invention.

FIG. 4 is a perspective view showing a process of a film forming method according to a fourth embodiment of the present invention.

FIG. 5 is a diagram showing a process of a film forming method according to a fifth embodiment of the present invention.

FIG. 6 is a view showing an aluminum film forming mask according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flexible printed board 4 Metal mask for film formation 8 Member which obstructs ventilation 13 Plate material which presses mask 21 Metal mask for film formation 22 Flexible printed circuit board 23 Fixing jig 30 Base for holding flexible printed circuit board 31 Metal mask for film formation 32 Flexible printed circuit board 33 Fixing jig 40 Flexible printed circuit board holding base 41 Metal mask for film formation 42 Flexible printed circuit board 43 Fixing jig 60 Mask 62 Member that inhibits ventilation

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Yuichi Nakagami 1006 Kazuma Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. F term (reference) 4K029 BA03 BD00 HA04 5E343 AA33 BB28 DD23 DD25 FF30 GG06

Claims (5)

[Claims] 1. A step of installing a mask having a member that inhibits airflow around a film-forming opening on a flexible printed circuit board bonded with an adhesive;
Forming a metal film on the substrate. 2. The film forming method according to claim 1, wherein the substrate surface and the mask are pressed by a member having a spring property. 3. A step of installing a mask on a flexible printed circuit board mounted on a base having a convex curved surface and bonded with an adhesive; A film forming method, comprising: pressing the mask; and forming a metal film on the substrate. 4. The film forming method according to claim 4, wherein a member that inhibits ventilation is formed around the film forming opening of the mask. 5. A method for manufacturing a printed circuit board, comprising a step of forming a film by the method according to claim 1.