Apparatus for detecting press-bonded ball at bonding portion in bonding apparatus and method for detecting press-bonded ball at bonding portion

A method for detecting a press-bonded ball at a bonding portion after bonding in a bonding apparatus including a capillary capable of performing bonding onto a workpiece and a detection camera disposed with a certain amount of offset from the capillary, the method comprising the steps of:

• selecting a first pad having thereon a press-bonded ball whose edges corresponding to two adjacent sides of the first pad are definite;
• detecting distances between the two sides of the first pad and the respective edges;
• comparing the detected values to determine whether or not the detected values respectively fall within predetermined allowable ranges;
• correcting the amount of offset, if either of the detected values is outside an allowable range thereof, so that the press-bonded ball comes within the allowable range;
• selecting a second pad having thereon a press-bonded ball whose edges corresponding to two adjacent sides of the second pad are definite, the two adjacent sides of the second pad being other than the sides corresponding to the two adjacent sides of the first pad;
• detecting distances between the two sides of the first pad and the respective edges;
• and
• calculating a diameter of the press-bonded ball and positional displacement of the press-bonded ball according to the detected values for the first pad and the second pad.

A method for detecting a press-bonded ball at a bonding portion after bonding in a bonding apparatus including a capillary capable of performing bonding onto a workpiece and a detection camera disposed with a certain amount of offset from the capillary, the method comprising the steps of:

• selecting a first pad having thereon a press-bonded ball whose edge corresponding to a side in an X direction of the first pad is definite, as well as a second pad having thereon a press-bonded ball whose edge corresponding to a side in a Y direction of the second pad is definite;
• detecting distances between the two sides of the first and second pads and the respective edges;
• comparing the detected values to determine whether or not the detected values respectively fall within predetermined allowable ranges;
• correcting the amount of offset, if either of the detected values is outside an allowable range thereof, so that the press-bonded ball comes within the allowable range;
• selecting a third pad having thereon a press-bonded ball whose edge corresponding to a side in an X direction of the third pad is definite, as well as a fourth pad having thereon a press-bonded ball whose edge corresponding to a side in a Y direction of the fourth pad is definite, the respective sides of the third and fourth pads being other than and correspond to the respective sides of the first and second pads;
• detecting distances between the two sides of the third and fourth pads and the respective edges of the press-bonded balls thereon;
• and
• calculating a diameter of the press-bonded ball and a positional displacement of the press-bonded ball according to the detected values for the first and second pads, and the detected values for the third and fourth pads.

An apparatus for detecting a press-bonded ball by imaging a bonding portion after bonding used in a bonding apparatus provided with a capillary capable of performing bonding onto a workpiece and a detection camera disposed with a certain amount of offset from the capillary, the apparatus comprising:

• a capillary capable of performing bonding onto a workpiece;
• a pad width memory storing widths in an X direction and in a Y direction of a pad;
• an allowance memory storing allowable ranges for a distance between a side of the pad in an X direction and an edge of a press-bonded ball, and a distance between a side of the pad in a Y direction and an edge of the press-bonded ball;
• a detection camera disposed with a certain amount of offset from the capillary, the detection camera detecting a distance between a side of a pad and an edge of a press-bonded ball in the X direction, as well as a distance between a side of a pad and an edge of a press-bonded ball in the Y direction, the edges of the press-bonded balls respectively in the X and Y directions being definite;
• a comparison circuit capable of comparing the detected values from the detection camera and the allowable ranges stored in the allowance memory;
• and
• a calculation control unit capable of correcting the amount of offset stored in an offset memory, if the comparison by the comparison circuit determines that either of the detected values is outside allowable range thereof.