SOI structure and method of producing same

A method of producing an SOI structure, comprising the steps of:

• providing a substrate having a silicon substrate, a BOX layer and an SOI layer;
• accumulating a pad oxide film, a nitride film and a first oxide layer on the SOI layer in sequence;
• patterning the nitride film and the first oxide layer of a device isolation area on the SOI layer by a mask as a pattern of restricting an active area forming part;
• ion-injecting impurities onto the resultant structure, and forming a well so that its lower surface is in contact with the BOX layer in the device isolation area;
• forming a spacer on both side walls of the nitride film and the first oxide layer remaining on an active area within the SOI layer;
• etching the pad oxide film and one portion of the well so that the well remains at a constant thickness on the BOX layer;
• forming a second oxide layer on the resultant structure;
• CMP-processing the second oxide layer so that the nitride film remains at a constant thickness on the active area, and forming a field oxide film of second oxide layer material on a surface of the well;
• eliminating all of the nitride film, the pad oxide film and the spacer remaining on the active area, and exposing the active area of the SOI layer;
• forming a gate line so as to be connected in one body across the active area and a constant portion of the field oxide film;
• forming an insulation layer on the resultant structure;
• executing a primary damascene process in which only the insulation layer on the device isolation area is selectively etched to a constant thickness so that the gate line on the field oxide film is partially exposed, and after that, performing a secondary damascene process in which the insulation layer on the active area is selectively etched in a constant portion so that the active area is partially exposed, and forming an opening part which is opened in a full trench structure on the active area and which is opened in a partial trench structure on the field oxide film;
• and
• filling up the opening part with a metal film, CMP-processing it, and forming an LIC.

A method of making an SOI structure, comprising:

• forming a silicon layer on a substrate already having a first insulating layer thereon;
• masking an area of the silicon layer with a mask;
• ion implanting the silicon layer;
• etching a portion of the silicon layer not covered by the mask to form a well;
• removing the mask;
• forming a first and a second active area in the silicon layer that was previously covered by the mask;
• forming a second insulating layer on the well;
• forming a gate line on the second insulating layer, the gate line extending from the first active area to over a portion of the second insulating layer;
• forming a third insulating layer on the second insulating layer and on the second active area,
• removing a portion of the third insulating layer to leave a hole, such that, at a bottom of the hole in the third insulating layer, the third insulating layer has a thickness of about one-half the thickness of the gate line;
• forming an opening in the hole in the third insulating layer to expose a portion of the second active area;
• and
• filling the hole in the third insulating layer with a metal so that the metal contacts both the second active area and an upper portion of the gate line.