Stmicroelectronics S.a.

Fran&ccedil;ois Leverd

Philippe Coronel

Michel Marty

Marc Piazza

H&eacute;l&egrave;ne Baudry

The invention relates to a DRAM integration method that does away with the alignment margins inherent to the photoetching step of the upper electrode of the capacitance for inserting the bit line contact. The removal of the upper electrode is self-aligned on the lower electrode of the capacitance. This is accomplished by forming a difference in topography at the point where the opening of the upper electrode is to be made, and depositing a non-doped polysilicon layer on the upper electrode. An implantation of dopants is performed on this layer, and the part of the non-doped layer located in the lower part of the zone showing the difference in topography is selectively etched. The remainder of the polysilicon layer and the part of the upper electrode located in the lower layer are also etched.

DRAM memory integration method

Prior fabricating the transistors, a phase of forming a deep insulative trench in the substrate is followed by a phase of forming a shallow insulative trench in the substrate and extending the deep trench. The phase of forming the deep trench includes coating the inside walls of the deep trench with an initial oxide layer and filling the deep trench with silicon inside an envelope formed from an insulative material. The phase of forming the shallow trench includes coating the inside walls of the shallow trench with an initial oxide layer and filling the shallow trench with an insulative material.

Growing community of inventors

St. Ismier, France

François Leverd

Growing community of inventors

St. Ismier, France

Fran&ccedil;ois Leverd

François Leverd