Stock material or miscellaneous articles – Structurally defined web or sheet – Including components having same physical characteristic in...
Reexamination Certificate
2001-09-21
2004-03-02
Nakarani, D. S. (Department: 1773)
Stock material or miscellaneous articles
Structurally defined web or sheet
Including components having same physical characteristic in...
C428S213000, C428S214000, C428S215000, C428S335000, C428S336000, C428S458000, C428S473500
Reexamination Certificate
active
06699572
ABSTRACT:
CROSS-REFERENCES TO RELATED APPLICATIONS
This application claims priority of Japanese Application No. 2000-286456 filed Sep. 21, 2000, the complete disclosure of which is hereby incorporated by reference.
FIELD OF THE INVENTION
This invention relates to a metal film/aromatic polyimide film laminate and further relates to a composite aromatic polyimide film.
BACKGROUND OF THE INVENTION
Aromatic polyimide films show good high temperature resistance, good chemical properties, high electrical insulating property, and high mechanical strength, and therefore are widely employed in various technical fields. For instance, an aromatic polyimide film is favorably employed in the form of a continuous aromatic polyimide film/metal film composite sheet for manufacturing a flexible printed circuit board (FPC), a carrier tape for tape-automated-bonding (TAB), and a tape of lead-on-chip (LOC) structure.
The aromatic polyimide film/metal film laminate can be produced by bonding a polyimide film to a metal film using a conventional adhesive such as an epoxy resin. However, due to low heat-resistance of the conventional adhesive, the produced composite sheet cannot show satisfactory high heat-resistance.
For obviating the above-mentioned problem, a variety of bonding methods have been proposed. For instance, an aromatic polyimide film/metal film composite sheet is manufactured by producing a copper metal film on an aromatic polyimide film by electroplating. Otherwise, an aromatic polyamide solution (i.e., a solution of a precursor of an aromatic polyimide resin) is coated on a copper film, dried, and heated for producing an aromatic polyimide film on the copper film.
An aromatic polyimide film/metal film composite sheet also can be produced using a thermoplastic polyimide resin.
U.S. Pat. No. 4,543,295 describes that a metal film/aromatic polyimide film laminate in which the metal film is bonded to the polyimide film at a high bonding strength is prepared by combining, by heating under pressure, a metal film and a composite aromatic polyimide film composed of a highly heat resistant substrate film and a thermoplastic thin polyimide layer bonded to the substrate film at an extremely high bonding strength. It has been found, however, that some composite aromatic polyimide films have unsatisfactory resistance to a chlorine-containing solvent such as methylene chloride. The methylene chloride and analogous compounds are employed for washing a metal film/aromatic polyimide film laminate before or after etching the laminate.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a metal film/aromatic polyimide film laminate in which a metal film is bonded to an aromatic polyimide film at a high bonding strength, and the aromatic polyimide film has high resistance to a chlorine-containing solvent such as methylene chloride.
The invention resides in a metal film/aromatic polyimide film laminate comprising a composite aromatic polyimide film and a metal film, in which the composite aromatic polyimide film is composed of an aromatic polyimide substrate film having a linear expansion coefficient of 5×10
−6
to 30×10
−6
cm/cm/° C. in the temperature range of 50 to 200° C., the coefficient being a value measured in a machine direction of the substrate film, and a thin aromatic polyimide layer comprising polyimide prepared from a carboxylic acid component comprising a mixture of 3,3′,4,4′-biphenyltetracarboxylic dianhydride and 2,3,3′,4′-biphenyltetracarboxylic dianhydride in a molar ratio of 50:50 to 90:10 and an aromatic diamine component comprising 1,3-bis(4-aminophenoxy)benzene or a mixture of 1,3-bis(4-aminophenoxy)benzene and at least one diamine component selected from the group consisting of p-phenylenediamine and diaminodiphenyl ether in a molar ratio of 10/90 or more, the polyimide of the thin aromatic polyimide layer having a glass transition temperature of 210 to 310° C., and the metal film being fixed to the thin aromatic polyimide layer at a 90° peel resistance of 0.5 kg/cm or higher, while the thin polyimide layer being bonded to the polyimide substrate film at a 90° peel resistance higher than the peel resistance between the metal film and the thin polyimide layer.
The invention further resides in a process comprising etching the metal film of the metal film/aromatic polyimide film laminate of the invention and washing the etched laminate with a chlorine-containing solvent.
The invention furthermore resides in a process comprising washing the metal film of the metal film/aromatic polyimide film laminate of the invention with a chlorine-containing solvent and etching the washed laminate.
The invention furthermore resides in a composite aromatic polyimide film composed of an aromatic polyimide substrate film having a linear expansion coefficient of 5×10
−6
to 30×10
−6
cm/cm/° C. in the temperature range of 50 to 200° C., the coefficient being a value measured in a machine direction of the substrate film, and a thin aromatic polyimide layer comprising polyimide prepared from a carboxylic acid component comprising a mixture of 3,3′,4,4′-biphenyltetracarboxylic dianhydride and 2,3,3′,4′-biphenyltetracarboxylic dianhydride in a molar ratio of 50:50 to 90:10 and an aromatic diamine component comprising 1,3-bis(4-aminophenoxy)benzene or a mixture of 1,3-bis(4-aminophenoxy)benzene and at least one diamine component selected from the group consisting of p-phenylenediamine and diaminodiphenyl ether in a molar ratio of 10/90 or more, the polyimide of the thin aromatic polyimide layer having a glass transition temperature of 210 to 310° C., and the thin polyimide layer being bonded to the polyimide substrate under the condition that the thin polyimide layer cannot be peeled off from the polyimide substrate film without breakage of the thin polyimide layer.
DETAILED DESCRIPTION OF THE INVENTION
The metal film/aromatic polyimide film laminate of the invention comprises a composite aromatic polyimide film and a metal film.
The composite aromatic polyimide film is composed of an aromatic polyimide substrate film having a relatively low linear expansion coefficient such as 5×10
−6
to 30×10
−6
cm/cm/° C. in the temperature range of 50 to 200° C. (measured in a machine direction of the substrate film), and a thin aromatic polyimide layer comprising polyimide on which a metal film can be bonded by heating under pressure or a metal film can be formed by vacuum deposition or chemical plating. The thin aromatic polyimide layer can be provided to both surfaces of the substrate film. Therefore, a metal film can be fixed to each thin polyimide layer on both sides of the composite film.
The thin aromatic polyimide layer has a thickness less than the thickness of the substrate film. The polyimide substrate has a thickness generally in the range of 5 to 125 &mgr;m, and the thin polyimide layer generally has a thickness of 1 to 25 &mgr;m, preferably 1 to 15 &mgr;m, more preferably 2 to 12 &mgr;m. The thickness of the composite polyimide film generally is in the range of 7 to 125 &mgr;m, preferably 7 to 50 &mgr;m, more preferably 7 to 25 &mgr;m.
The metal film is fixed to the thin aromatic polyimide layer at a 90° peel resistance of 0.5 kg/cm or more, preferably 0.7 kg/cm or more, more preferably 1.0 kg/cm or more, while the thin polyimide layer is bonded to the polyimide substrate film at a 90° peel resistance higher than the peel resistance between the metal film and the thin polyimide layer. The bonding between the thin polyimide layer and the substrate film preferably is extremely strong so that the thin polyimide layer cannot be peeled off from the substrate film without breakage of the thin polyimide layer.
The polyimide of the thin polyimide layer is prepared from a carboxylic acid component comprising a mixture of 3,3′,4,4′-biphenyltetracarboxylic dianhydride and 2,3,3′,4′-biphenyltetracarboxylic dianhydride in a molar ratio of 50:50 to 90:10, preferably 6
Amane Takashi
Anno Toshihiko
Nishino Toshiyuki
Yamamoto Tomohiko
Nakarani D. S.
Reed Smith LLP
Ube Industries Ltd.
LandOfFree
Metal film/aromatic polyimide film laminate does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Metal film/aromatic polyimide film laminate, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Metal film/aromatic polyimide film laminate will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3207962