Adhesive Film and Use Thereof

• US 20080305346A1
• Filed: 07/20/2005
• Published: 12/11/2008
• Est. Priority Date: 07/27/2004
• Status: Active Grant

• Current Assignee: Kaneka Corporation
• Original Assignee: Kaneka Corporation
• Inventors: Kaneshiro, Hisayasu, Yanagida, Masami
• Granted Patent: US 7,858,200 B2
• Time in Patent Office: Days
• US Class Current: 428/473.5
• CPC Class Codes: B32B 15/08 of synthetic resin
• CPC Class Codes: B32B 2311/00 Metals, their alloys or their compounds
• CPC Class Codes: B32B 2379/08 Polyimides
• CPC Class Codes: B32B 2457/08 PCBs, i.e. printed circuit boards
• CPC Class Codes: B32B 37/12 characterised by using adhesives
• CPC Class Codes: B32B 37/153 at least one layer is extruded and immediately laminated while in semi-molten state
• CPC Class Codes: C09J 179/08 Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
• CPC Class Codes: C09J 2203/326 for bonding electronic components such as wafers, chips or semiconductors
• CPC Class Codes: C09J 2479/08 polyimide
• CPC Class Codes: C09J 2479/086 in the substrate
• CPC Class Codes: C09J 7/20 characterised by their carriers
• CPC Class Codes: C09J 7/25 based on macromolecular compounds obtained otherwise than by reactions involving only carbon-to-carbon unsaturated bonds
• CPC Class Codes: H01L 21/4846 Leads on or in insulating or insulated substrates, e.g. metallisation H01L21/4821 takes precedence; metallisation of ceramics in general C04B41/51; printed circuits H05K3/00
• CPC Class Codes: H01L 23/481 Internal lead connections, e.g. via connections, feedthrough structures
• CPC Class Codes: H01L 23/4985 Flexible insulating substrates H01L23/49572 and H01L23/49855 take precedence
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H05K 1/0346 containing N
• CPC Class Codes: H05K 2201/0129 Thermoplastic polymer, e.g. auto-adhesive layer; Shaping of thermoplastic polymer
• CPC Class Codes: H05K 2201/0154 Polyimide
• CPC Class Codes: H05K 2201/0355 : Metal foils
• CPC Class Codes: H05K 3/386 : by the use of an organic polymeric bonding layer, e.g. adhesive
• CPC Class Codes: Y10T 428/31678 : Of metal
• CPC Class Codes: Y10T 428/31681 : Next to polyester, polyamide or polyimide [e.g., alkyd, glue, or nylon, etc.]
• CPC Class Codes: Y10T 428/31721 : Of polyimide

Abstract

Disclosed in an adhesive film which enables to obtain a flexible metal clad laminate which is suppressed in dimensional change when produced by heat roll lamination. Such an adhesive film comprises a heat-resistant layer containing a highly heat resistant polyimide and an adhesive layer which is formed on at least one surface of the heat-resistant layer and contains a thermoplastic polyimide. In this adhesive film, the thermal shrinkage ratio in the TD direction is not less than +0.01%, and the thermal shrinkage ratio in the MD direction is not more than −0.02%. Consequently, when a metal layer and the adhesive film are bonded together by heat roll lamination and the resulting laminate is subjected to a treatment with heating, occurrence of dimensional changes can be sufficiently suppressed.

Claims

1. An adhesive film including (i) a heat resistant layer containing a highly heat resistant polyimide, and (ii) an adhesive layer on at least one surface of the heat resistant layer, the adhesive layer containing a thermoplastic polyimide,

wherein a thermal shrinkage ratio in a TD direction is +0.01% or more, and a thermal shrinkage ratio in an MD direction is −

0.02% or less.

2. The adhesive film as set forth in claim 1, wherein the heat resistant layer and the adhesive layer on the at least one surface of the heat resistant layer are formed by a coextrusion-flow casting method.

3. The adhesive film as set forth in claim 1, wherein the heat resistant layer and the adhesive layer on the at least one surface of the heat resistant layer are formed by a gel applying method.

4. The adhesive film as set forth in claim 1, wherein the thermal shrinkage ratio in the TD direction is +0.03% or more, and the thermal shrinkage ratio in the MD direction is −

0.05% or less.

5. The adhesive film as set forth in claim 1, wherein the adhesive layer is formed on each side of the heat resistant layer.

6. The adhesive film as set forth in claim 1, wherein the heat resistant layer contains a non-thermoplastic polyimide resin by 90 wt. % or more as the highly heat resistant polyimide.

7. The adhesive film as set forth in claim 1, wherein tensile elastic moduli in the TD direction and MD direction are within a range of 5.0 to 11 GPa.

8. A laminate comprising an adhesive film including (i) a heat resistant layer containing a highly heat resistant polyimide, and (ii) an adhesive layer on at least one surface of the heat resistant layer, the adhesive layer containing a thermoplastic polyimide,

wherein a thermal shrinkage ratio in a TD direction is +0.01% or more, and a thermal shrinkage ratio in an MD direction is −

0.02% or less.

9. The laminate as set forth in claim 8 comprising a metal layer on the adhesive film.

10. A flexible wiring board comprising an adhesive film or a laminate comprising the adhesive film,

the adhesive film including (i) a heat resistant layer containing a highly heat resistant polyimide and (ii) an adhesive layer on at least one surface of the heat resistant layer, the adhesive layer containing a thermoplastic polyimide,

wherein a thermal shrinkage ratio in a TD direction is +0.01% or more, and a thermal shrinkage ratio in an MD direction is −

0.02% or less.

11. A method for producing an adhesive film comprising:

concurrently supplying, into an extruder having a dice for extruding in two or more layers, an organic solvent solution containing a polyamide acid that is a precursor of the highly heat resistant polyimide, and either an organic solvent solution containing the thermoplastic polyimide, or an organic solvent solution containing a polyamide acid that is a precursor of the thermoplastic polyimide, and extruding the organic solvent solutions via an outlet of the dice to form a thin film having at least two layers;

continuously supplying the extruded organic solvent solutions on a smooth-surfaced supporter, and volatilizing off at least part of an organic solvent or organic solvents from the thin film on the supporter in order to obtain a laminate film that is self-supportive; and

holding both edges of the laminate film in the TD direction and subjecting the laminate film to imidation while elongating the laminate film in the TD direction to an elongation ratio of greater than 1.0,

wherein the adhesive film includes (i) a heat resistant layer containing a highly heat resistant polyimide, and (ii) an adhesive layer on at least one surface of the heat resistant layer, the adhesive layer containing a thermoplastic polyimide,

a thermal shrinkage ratio in a TD direction is +0.01% or more, and a thermal shrinkage ratio in an MD direction is −

0.02% or less, and

the heat resistant layer and the adhesive layer on the at least one surface of the heat resistant layer are formed by a coextrusion-flow casting method.

12. A method for producing an adhesive film,

forming a gel film by shaping, into a film-like shape, an organic solvent solution containing a polyamide acid, which is a precursor of the highly heat resistant polyimide;

applying on at least one surface of the gel film an organic solvent solution containing a thermoplastic polyimide or an organic solvent solution containing a polyamide acid that is a precursor of the thermoplastic polyimide, and heating the gel film on which the organic solvent solution is applied; and

holding both edges of the laminate film in the TD direction and subjecting the laminate film to imidation while elongating the laminate film in the TD direction to an elongation ratio of greater than 1.0,

wherein the adhesive film includes (i) a heat resistant layer containing a highly heat resistant polyimide, and (ii) an adhesive layer on at least one surface of the heat resistant layer, the adhesive layer containing a thermoplastic polyimide,

a thermal shrinkage ratio in a TD direction is +0.01% or more, and a thermal shrinkage ratio in an MD direction is −

0.02% or less, and

the heat resistant layer and the adhesive layer on the at least one surface of the heat resistant layer are formed by a gel applying method.

13. A method for producing a flexible wiring board including an adhesive or a laminate comprising the adhesive film, the method comprising:

providing a metal foil on the adhesive film by a heat roll laminating method,

wherein the adhesive film includes (i) a heat resistant layer containing a highly heat resistant polyimide, and (ii) an adhesive layer on at least one surface of the heat resistant layer, the adhesive layer containing a thermoplastic polyimide,

a thermal shrinkage ratio in a TD direction is +0.01% or more, and a thermal shrinkage ratio in an MD direction is −

0.02% or less.