Method of making a nonvolatile memory cell using EPROM mask and ROM processing steps

US6087228A · kind A · utility

Assignee

• STMicroelectronics SA

Inventors

• Emilio Ghio · Milano, IT
• Giuseppe Meroni · Lecco, IT

Key dates

• Filing date: Jul 9, 1997
• Grant date: Jul 11, 2000
• Expiry date: Jul 9, 2017

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10B20/00

Abstract

The invention relates to a method of automatically shifting from the fabrication of an EPROM cell to the fabrication of a ROM cell, which method is specifically intended for semiconductor electronic circuits having a resident memory and is of the type wherein the structure of at least one memory cell transistor is defined on a semiconductor substrate using photolithographic techniques including an active area and a channel region, the cell being adapted to acquire a logic state selected by the user. Advantageously, the conductivity of the active area is changed to suit the logical contents that the cell is intended to contain.