Abstract The upper-limit height of a solder portion based on the thickness of a lead or a chip is set, and the maximum height of the solder portion measured with a laser beam is compared with the set upper-limit height, thereby to judge the acceptance or rejection of the shape of the solder portion. In addition, the lower-limit height of a solder portion based on the thickness of a lead or a chip is set, and the maximum height of the solder portion measured with a laser beam is compared with the set lower-limit height, thereby to judge the acceptance or rejection of the shape of the solder portion. Besides, the lower-limit wetting angle of a solder fillet is set, and the wetting angle of the solder fillet measured with a laser beam is compared with the set lower-limit wetting angle, thereby to judge the acceptance or rejection of the shape of the solder fillet.
A method of checking an external shape of a solder portion of a chip which includes a mold member, a lead and said solder portion, the solder portion bonding said chip to a circuit board, comprising the steps of: (a) establishing a starting point at an upper surface of the mold member of said chip; (b) sweepingly projecting a laser beam from said starting point to said solder portion; (c) employing a position sensor to detect light reflected from said chip and said solder portion in order to measure an external shape of said chip and to detect a location of a reference part of the chip having a height at a predetermined ratio to a height of an upper surface of said molder member; (d) establishing an offset position which is offset by a predetermined distance from said location of said reference part toward the solder portion; and (e) sweepingly projecting the laser beam from said offset position toward an outer end of said solder portion in order to measure an external shape of said solder portion.
Claim 2
Independent Claim
178 words
A method of checking an external shape of a solder portion of a chip which includes a mold member, a lead and said solder portion, the solder portion bonding said chip to a circuit board, comprising the steps of: (a) establishing a starting point at an upper surface of the mold member of said chip; (b) sweepingly projecting a laser beam from said starting point to said solder portion; (c) employing a position sensor to detect light reflected from said chip and said solder portion in order to measure an external shape of said chip and to detect a location of a reference part of the chip having a height at a predetermined ratio to a height of an upper surface of said molder member; (d) establishing an offset position which is offset by a predetermined distance from said location of said reference part toward the solder portion; and (e) sweepingly projecting the laser beam from said offset position toward an outer end of said solder portion in order to measure an external shape of said solder portion.