The SWAMI - A defect free and near-zero bird's-beak local oxidation process and its application in VLSI technology

Abstract

A new scneme for SWAMI (Side fll1 Masked -Isolation) process is presented which takes full advantage o f LOCOS processing w i t h o u t suffering the difficulties.The new SWAMI technology incorporates a sloped silicon sidewall and thin nitride around the i s l a n d sidewalls such t h a t b o t h i n t r i n s i c n i t r i d e s t r e s s and volume expansion induced stress are greatly reduced. A defect free and near-zero bird's beak local oxidation process can be realized by the SWAMI. Fabrication technology and MOSFET electrical characteristics will be discussed. A SWAWI/CMOS circuit including 60K ROM, 2.5K SRAM, and 100 segments o f display driver w i t h 5.13 x 5.22 m2 chip size has been successfully fabricated.The results indicate that the SWAMI i s capable o f replacing the LOCOS as the isolation technology for scaled VLSI circuit fabrication.

Defect Characteristics and Generation Mechanism in a Bird Beak Free Structure by Sidewall Masked Technique

“…However, defect-free structures can still be obtained for small island patterns. In order to achieve both defect and bird beak free isolation technique, alterations in structural details and processing conditions are required (15).…”

A Bird's‐Beak‐Free Sealed‐Interface Local Oxidation Technology for Submicron Ultra‐Large‐Scale Integrated Circuits

“…Various kinds of isolation methods (Fig. 1) have been proposed (1)(2)(3)(4)(5)(6)(7) and used in industry. However, most of them have been finally rejected through the course of IC developments, and only a limited number of isolation technologies are in use at present.…”

LOPOS: Advanced Device Isolation for a 0.8 μm CMOS/BULK Process Technology

“…These techniques can be classified into two main groups, depending on the method of bird's beak reduction: (i) nitride passivation of the active area, e.g., sealed-interface local oxidation (3)(4)(5); (ii) edge passivation with nitride wedges or spacers to block lateral oxygen diffusion, e.g., side wall mask isolation and its derivatives (6)(7)(8)(9). These techniques can be classified into two main groups, depending on the method of bird's beak reduction: (i) nitride passivation of the active area, e.g., sealed-interface local oxidation (3)(4)(5); (ii) edge passivation with nitride wedges or spacers to block lateral oxygen diffusion, e.g., side wall mask isolation and its derivatives (6)(7)(8)(9).…”