High GCR Embedded OTP Technology In Eeprom Smartcard SOC Platform

In an EEPROM smart card SOC platform, EEPROM is usually combined with other types of memories, for example with Mask ROM. However, with the continuous development of smart card, embedded Mask ROM cannot meet the ever growing application demands gradually because of its inherited limitations. In the meanwhile, embedded OTP is easy to redesign and its stock can be easily controlled. Therefore, EEPROM / OTP combination becomes a new choice.To be embedded in an EEPROM smart card SOC platform, a novel OTP cell was proposed. The cell was optimized based on traditional ETOX OTP, so that the floating gate was completely covered by the control gate to achieve optimized embedding during processing. The same structure also enhanced the Gate Coupling Ratio up to 77%, where the new GCR technique was adopted in the extraction process. The result was very close to the designed value of 75.5%, and the error was within 2%.During processing, how to embed novel OTP cell in a 0.18um EEPROM smart card process is the key. This thesis solved the problem of the difference between novel OTP and EEPROM. It also improved the OPC based on the specialty of an EEPROM process. S/D definition and other processes were also adjusted accordingly. Finally, the novel OTP cell and other devices on the SOC platform are both processed successfully.When doing electrical characterization tests of the novel OTP cells, this thesis defined device operation conditions and standards according to the OTP cell performance and they meet the IC standards. Especially this thesis proposed process and layout optimization to solve the problems of programming interference and insufficient UV erase capability. The resulted novel OTP cell had outstanding performance, while other devices on the same SOC platform were not affected.