| 摘要 |
PURPOSE:To obtain a Vcp generator which can detect damage mode of a memory cell during manufacturing steps of a semiconductor memory by providing a cell plate potential generator in which a cell plate potential is varied by laser trimming. CONSTITUTION:A Vout, potential of a detecting resistance circuit 9 becomes a Vcp generating voltage as it is, but is a potential which can accelerate oxide film leakage malfunction of a memory cell. In a test before laser trimming to replace the malfunctioned cell during manufacturing steps with a memory cell of a redundant circuit by accelerating the malfunction in an initial state, the leakage malfunction is replaced with a redundancy memory cell in testing and laser trimming steps, and a fuse 10 of F1 is cut in this case to be able to set to the state of outputting a normal l/2VCC level to the Vout. Thus, since the plate potential can be arbitrarily varied from the normal 1/2VCC to l/2VCC or higher during manufacturing steps, a malfunction of improper oxide film leakage of the cell can be easily detected, and a proper product can be formed by replacing it with the redundancy memory cell. |
