Wire bonding device and wire bonding process using same

1 . A wire bonding device, comprising:

a capillary, containing a wire inserted therethrough; a moving mechanism for moving said capillary for X, Y, and Z directions;

an ultrasonic wave-applying unit for oscillatively generating ultrasonic wave to apply ultrasonic vibration to said capillary;

a movement control unit for detecting Z-axis moving speed of said capillary in a predetermined bonding position on a work, and then controlling Z-axis movement of said capillary with said moving mechanism when the Z-axis moving speed of said capillary is equal to or lower than a predetermined threshold;

a Z-axis position detecting unit for detecting Z-axis position of said capillary in the bonding position;

a calculating unit for calculating a displacement in the Z-axis position after the Z-axis moving speed obtained by said movement control unit reaches equal to or lower than the threshold on the basis of time-dependent change of the Z-axis position of said capillary;

a storage unit for storing the displacement occurred when said wire is bonded to said workpiece, as a reference displacement;

an electrical non-stick detecting unit for detecting a non-stick of said wire on the basis of a conducting condition between said wire and said workpiece;

a judging unit for judging whether a difference between the reference displacement and the displacement when a non-stick of said wire is detected by said electrical non-stick detecting unit is within a predetermined range or not; and

a correction unit for correcting any one of the threshold and the oscillation output of the ultrasonic wave if said judging unit judges that a difference between the reference displacement and the displacement when a non-stick of said wire is detected by said electrical non-stick detecting unit is out of a predetermined range.

2 . The wire bonding device as set forth in claim 1 , wherein said correction unit increases the oscillation output of the ultrasonic wave, if said judging unit judges that the difference between the reference displacement and the displacement when a non-stick of said wire is detected by said electrical non-stick detecting unit is out of a predetermined range.

3 . The wire bonding device as set forth in claim 1 , wherein said correction unit reduces the oscillation output of the ultrasonic wave, if said judging unit judges that the difference between the reference displacement and the displacement when a non-stick of said wire is detected is out of a predetermined range.

4 . The wire bonding device as set forth in claim 1 , wherein said storage unit stores the oscillation output of the ultrasonic wave when said wire is bonded to said workpiece, as a reference output,

wherein said calculating unit detects a difference between the reference output and the oscillation output when said electrical non-stick detecting unit detects a non-stick of said wire, said judging unit judges whether a predetermined level of ultrasonic wave is provided to said capillary or not, on the basis of the difference between the reference output and the oscillation output when said electrical non-stick detecting unit detects a non-stick of said wire, and

wherein said correction unit controls the oscillation output of the ultrasonic wave when said judging unit judges that a predetermined level of ultrasonic wave is not provided to said capillary.

5 . The wire bonding device as set forth in claim 1 , wherein said correction unit corrects the threshold, if said judging unit judges that the difference between the reference displacement and the displacement when a non-stick of said wire is detected is out of a predetermined range.

6 . The wire bonding device as set forth in claim 1 , further comprising an error output unit for outputting an error, if said judging unit judges that the difference between the reference displacement and the displacement when a non-stick of said wire is detected is within a predetermined range.

7 . A wire bonding process, comprising:

inserting a wire in a capillary;

moving said capillary for X, Y, and Z directions;

oscillatively generating ultrasonic wave to apply ultrasonic vibration to said capillary;

detecting Z-axis moving speed of said capillary in a predetermined bonding position on a workpiece and controlling the Z-axis movement of said capillary if the Z-axis moving speed of said capillary is equal to or lower than a predetermined threshold;

detecting the Z-axis position of said capillary in the bonding position;

calculating a displacement in the Z-axis position after the Z-axis moving speed of said capillary reaches equal to or lower than the threshold on the basis of time-dependent change of the Z-axis position of said capillary;

storing the displacement occurred when said wire is bonded to said workpiece, as a reference displacement;

detecting a non-stick of said wire on the basis of a conducting condition between said wire and said workpiece;

judging whether a difference between the reference displacement and the displacement when a non-stick of said wire is detected on the basis of the conducting condition is within a predetermined range or not; and

correcting any one of the threshold and the oscillation output of the ultrasonic wave if it is judged that a difference between the reference displacement and the displacement when a non-stick of said wire is detected is out of a predetermined range.