Copper wire and method of manufacturing the same

Abstract

A copper wire includes a copper wire rod including 5 to 55 mass ppm of Ti, 3 to 12 mass ppm of sulfur, and 2 to 30 mass ppm of oxygen with the balance copper and inevitable impurities, a first crystal including a [111] crystal orientation and at least one twin crystal therein, and a second crystal that includes one or more crystals adjacent to the first crystal, a [111] crystal orientation with a different rotation angle on an atomic plane from the first crystal, and at least one twin crystal therein.

What is claimed is: 
     
         1 . A copper wire, comprising:
 a copper wire rod comprising 5 to 55 mass ppm of Ti, 3 to 12 mass ppm of sulfur, and 2 to 30 mass ppm of oxygen with the balance copper and inevitable impurities;   a first crystal comprising a [111] crystal orientation and at least one twin crystal therein; and   a second crystal that comprises one or more crystals adjacent to the first crystal, a [111] crystal orientation with a different rotation angle on an atomic plane from the first crystal, and at least one twin crystal therein.   
     
     
         2 . The copper wire according to  claim 1 , wherein the first or second crystal is not more than 100 μm in size. 
     
     
         3 . The copper wire according to  claim 1 , wherein the twin crystals in the first or second crystal are formed at a distance of not less than 0.1 mm and not more than 0.5 mm. 
     
     
         4 . The copper wire according to  claim 1  further comprising a half-softening temperature of not less than 130° C. and not more than 200° C. 
     
     
         5 . The copper wire according to  claim 1  further comprising a thin film that comprises Sn, Ag, solder, amorphous zinc and oxygen and is formed on a surface of the copper wire rod. 
     
     
         6 . A method of manufacturing a copper wire, comprising conducting a heat treatment to a copper wire rod comprising 5 to 55 mass ppm of Ti, 3 to 12 mass ppm of sulfur, and 2 to 30 mass ppm of oxygen with the balance copper and inevitable impurities under a condition of a heat treatment temperature of not less than 700° C. and not more than 950° C. and heat treatment time of not less than 60 minutes and not more than 120 minutes so as to obtain a copper wire comprising a first crystal comprising a [111] crystal orientation and at least one twin crystal therein and a second crystal that comprises one or more crystals adjacent to the first crystal, a [111] crystal orientation with a different rotation angle on an atomic plane from the first crystal and at least one twin crystal therein. 
     
     
         7 . The method according to  claim 6 , wherein the heat treatment is conducted in an argon or nitrogen atmosphere by using a tubular electric furnace, an electric annealer, a gold furnace or continuous plasma heat treatment.