| 摘要 |
PURPOSE:To facilitate the discrimination of a masked ROM, by writing the difference of ICs due to the storage information into an IC chip according to the difference of form of the P type well diffusion layers. CONSTITUTION:A CMOS is formed with an N type substrate 101, a P type diffusion layer 102, a P type diffusion layer 103, an N type diffusion layer 104, a gate 105, an oxidized film 106 and a gate insulating film 107. The layer 102 formed at the early period is called P well and can easily be discriminated above the ware and by amicroscope in the subsequent processes. Thus the flowing mistake can be completely eliminated. For the visual discrimination to the final chip, the characters or marks are written by giving the photoetching to the final passivation film 303 on a dummy AL butt 302. In such way, the discrimination of IC is facilitated. |
