PURPOSE:To improve accuracy of laser trimming, by determining whether a found chip is good one (as RE article) or not when replaced by a spare memory, in accordance with the existence of a mark on a pad. CONSTITUTION:When a RE article 7 is found on the base of chip coordinate information by a laser trimmer 3 in which a coordinate system is found, the existence of a scratch mark 11 is judged on a detection pad of the RE article 7. If the scratch mark 11 is found in this article, the article as a deffective memory is replaced by a substitutive one by means of a laser blow. After recognition of whether chip-positioning information of the RE article 7 obtained by a tester 1 is good or not is made by detecting the scratch mark 11 in this way, a laser blow is performed. It can be thus determined whether the information by the tester 1 is good or otherwise the coordinate system is properly found by the trimmer 3. Laser trimming can be hence accurately performed.
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