| 摘要 |
PURPOSE:To greatly reduce TAT by a method wherein a conductive mask, with an ion-driving opening provided therein corresponding to a memory device region whose threshold voltage is altered by impurity ion implantation, is formed on a memory cell group, and is electrically connected to a substrate with the intermediary of an insulating layer. CONSTITUTION:Boron ions are driven into a channel region of an IGFET Q4, through an opening 2 provided in an aluminum layer forming a conductive mask, for the write of code. Reduction is attained in the quantity of energy required for ion implation when an insulating layer 11, PSG film 7 and an SiO2 film 6 is subjected to etching deep enough to properly reach an conductor layer 8 during the process of providing the opening 2 in an aluminum layer 12 by etching with a resist film serving as a mask. After this process, the photoresist is removed, which is followed by annealing for the activation of the boron ions. Finally, a passivation film 15 is formed to serve as the final protecting film. This greatly reduces TAT. |
