Thermoplastic liquid crystal polymer film, circuit board, and methods respectively for manufacturing said film and said circuit board

Abstract

Provided are a thermoplastic liquid crystal polymer film having an improved thermo-adhesive property, a circuit board, and methods respectively for producing the same. The thermoplastic liquid crystal polymer film has a segment orientation ratio SOR of 0.8 to 1.4 and a moisture content of 300 ppm or less. The circuit board contains a plurality of circuit board materials wherein the circuit board materials are at least one member selected from the group consisting of an insulating substrate having a conductor layer on at least one surface, a bonding sheet, and a coverlay. At least one of the circuit board materials includes a thermoplastic liquid crystal polymer film. The circuit board shows a solder heat resistance when the circuit board is placed in a solder bath at 290° C. for 60 seconds in accordance with JIS C 5012.

1 - 17 . (canceled) 
     
     
         18 . A method for producing a thermoplastic liquid crystal polymer film, the method at least comprising:
 preparing a thermoplastic liquid crystal polymer film being capable of forming an optical anisotropic melt phase and having a segment orientation ratio SOR of 0.8 to 1.4, and   degassing the thermoplastic liquid crystal polymer film
 by degassing the film (i) under vacuum of 1500 Pa or lower for 30 minutes or more, 
 by degassing the film (ii) under heating at a temperature ranging from 100° C. to 200° C., or 
 by degassing the film under the above (i) and (ii) simultaneously or separately, 
   so as to produce a thermoplastic liquid crystal polymer film having a segment orientation ratio SOR of 0.8 to 1.4 and a moisture content in accordance with Karl Fischer method of 300 ppm or less.   
     
     
         19 . The method for producing a thermoplastic liquid crystal polymer film according to  claim 18 , wherein the degassing of the film is performed by a process comprising:
 a first degassing of the prepared thermoplastic liquid crystal polymer film under heating at a temperature ranging from 100° C. to 200° C. for a predetermined period of time, and   a second degassing of the thermoplastic liquid crystal polymer film after the first degassing under vacuum of 1500 Pa or lower for a predetermined period of time.   
     
     
         20 . The method for producing a thermoplastic liquid crystal polymer film according to  claim 18 , wherein the degassing under vacuum (i) is carried out while heating the film at a temperature ranging from 80° C. to 200° C. under vacuum of 1500 Pa or lower. 
     
     
         21 . The method for producing a thermoplastic liquid crystal polymer film according to  claim 19 , wherein the second degassing process is carried out while heating the film at a temperature ranging from 80° C. to 200° C. under vacuum of 1500 Pa or lower. 
     
     
         22 . The method for producing a thermoplastic liquid crystal polymer film according to  claim 18 , wherein the thermoplastic liquid crystal polymer film has a film thickness of 10 to 200 μm. 
     
     
         23 . The method for producing a thermoplastic liquid crystal polymer film according to  claim 18 , wherein the thermoplastic liquid crystal polymer film after degassing has a skin layer. 
     
     
         24 . The method for producing a thermoplastic liquid crystal polymer film according to  claim 18 , wherein the thermoplastic liquid crystal polymer film after degassing is used as an insulating substrate having a conductor layer on at least one surface. 
     
     
         25 . The method for producing a thermoplastic liquid crystal polymer film according to  claim 18 , wherein the thermoplastic liquid crystal polymer film after degassing is used as a bonding sheet. 
     
     
         26 . The method for producing a thermoplastic liquid crystal polymer film according to  claim 18 , wherein the thermoplastic liquid crystal polymer film after degassing is used as a coverlay. 
     
     
         27 . The method for producing a thermoplastic liquid crystal polymer film according to  claim 18 , wherein the thermoplastic liquid crystal polymer film to be subjected to degassing is in a sheet form or a roll form. 
     
     
         28 . The method for producing a thermoplastic liquid crystal polymer film according to  claim 18 , wherein the thermoplastic liquid crystal polymer film to be subjected to degassing is in a roll form having a winding thickness of 1000 mm or smaller. 
     
     
         29 . The method for producing a thermoplastic liquid crystal polymer film according to  claim 18 , wherein the thermoplastic liquid crystal polymer film after degassing is wrapped with a packaging material having a gas barrier property. 
     
     
         30 . A method for producing a circuit board at least comprising:
 preparing a plurality of circuit board materials;   stacking the prepared circuit board materials in accordance with a predetermined structure of a circuit board to obtain a stacked material, followed by conducting thermo-compression bonding of the stacked material by heating under a predetermined compression pressure; wherein   the prepared circuit board materials are at least one member selected from the group consisting of an insulating substrate having an conductor layer on at least one surface, a bonding sheet, and a coverlay, and   (I) at least one of the prepared circuit board materials comprises a degassed thermoplastic liquid crystal polymer film subjected to degassing as recited in  claim 18 ,   (II) at least one of the prepared circuit board materials comprises a non-degassed thermoplastic liquid crystal polymer film, and the degassing process as recited in  claim 18  is conducted after the preparation of the circuit board materials and before the thermo-compression bonding, or   (III) at least one of the prepared circuit board materials comprises a degassed thermoplastic liquid crystal polymer film subjected to degassing as recited in  claim 18  and the degassing process as recited in  claim 18  is conducted after the preparation of the circuit board materials and before the thermo-compression bonding.   
     
     
         31 . The method for producing a circuit board according to  claim 30 , wherein the thermo-compression bonding of the circuit board materials is performed by heating the materials while compressing the materials under a compression pressure of 5 MPa or lower. 
     
     
         32 . The method for producing a circuit board according to  claim 31 , wherein the thermo-compression bonding of the circuit board materials is performed by heating the materials while compressing the materials under a compression pressure of 0.5 to 2.5 MPa. 
     
     
         33 . The method for producing a circuit board according to  claim 30 , wherein the circuit board materials are heated at a temperature ranging from (Tm−60)° C. to (Tm+40)° C. during the thermocompression bonding, where Tm is the melting point of the thermoplastic liquid crystal polymer film subjected to the thermocompression bonding.