Chartered Semiconductor Manufacturing Ltd (corporation)

Pei Ching Lee

Mei Sheng Zhou

Soh Yun Siah

Eng Hua Lim

Kong Hean Lee

Chong Wee Lim

Wen Jun Liu

Yelehanka Ramachandramurthy Pradeep

Henry Gerung

Jie Yu

A method for dry plasma selective etching of a pattern in a silicon nitride dielectric layer formed over a semiconductor substrate employed within a microelectronics fabrication. There is provided a semiconductor substrate having formed thereupon a pad oxide layer over which is formed a silicon nitride dielectric layer. There is formed over the substrate a patterned photoresist etch mask layer. There is then selectively etched the pattern of the photoresist etch mask layer into the silicon nitride layer employing a four-step etching process with three plasma etching environments which include; (1) a &ldquo;break-through&rdquo; etching step; (2) a &ldquo;bulk&rdquo; etching step to remove a majority of the silicon nitride layer and a &ldquo;buffer&rdquo; etching step to remove the remainder of the silicon nitride layer; and (3) an &ldquo;over-etch&rdquo; step to complete removal of silicon nitride without excessive etching of underlying material. These steps comprise the selective etching of the patterned silicon nitride layer while maintaining control of critical dimensions, with attenuated microloading and over-etching of underlying material.

Multiple-step plasma etching process for silicon nitride

A process for forming salicided CMOS devices, and non-salicide CMOS devices, on the same semiconductor substrate, using only one silicon nitride layer to provide a component for a composite spacer on the sides of the salicided CMOS devices, and to provide a blocking shape during metal silicide formation, for the non-salicided CMOS devices, has been developed. The process features the use of a disposable organic spacer, on the sides of polysilicon gate structures, used to define the heavily doped source/drain regions, for all CMOS devices. A silicon nitride layer, obtained via LPCVD procedures, at a temperature between 800 to 900&deg; C., is then deposited and patterned to provide the needed spacer, on the sides of the CMOS devices experiencing the salicide process, while the same silicon nitride layer is used to provide the blocking shape needed to prevent metal suicide formation for the non-salicided CMOS devices.

Method of forming a sidewall spacer and a salicide blocking shape, using only one silicon nitride layer

A method for forming a stepped shallow trench isolation is described. A pad oxide layer is deposited on the surface of a semiconductor substrate. A first nitride layer is deposited overlying the pad oxide layer. The first nitride layer is etched through where it is not covered by a mask to provide an opening to the pad oxide layer. A first trench is etched through the pad oxide layer within the opening and into the semiconductor substrate. A second nitride layer is deposited overlying the first nitride layer and filling the first trench. Simultaneously, the second nitride layer is anisotropically etched to form nitride spacers on the sidewalls of the first trench and the semiconductor substrate is etched into where it is not covered by the spacers to form a second trench. Ions are implanted into the semiconductor substrate underlying the second trench. The first and second trenches are filled with an oxide layer. Thereafter, the first nitride and pad oxide layers are removed completing the formation of shallow trench isolation in the fabrication of an integrated circuit device. This nitride spacer STI architecture prevents STI corner oxide recess and enables borderless contact formation. This unique process reduces junction leakage and also reduces contact leakage.

Method of making low-leakage architecture for sub-0.18 .mu.m salicided

A novel anisotropic plasma etching process for forming patterned silicon nitride (Si.sub.3 N.sub.4) layers with improved critical dimension (CD) control while minimizing the Si.sub.3 N.sub.4 footing at the bottom edge of the Si.sub.3 N.sub.4 pattern is achieved. A pad oxide/silicon nitride layer is deposited on a silicon substrate. A patterned photoresist layer is used as an etching mask for etching the silicon nitride layer. By this invention, a chlorine (Cl.sub.2) breakthrough plasma pre-etch forms a protective polymer layer on the sidewalls of the patterned photoresist and removes residue in the open areas prior to etching the Si.sub.3 N.sub.4. The Si.sub.3 N.sub.4 is then aniso-tropically plasma etched using an etch gas containing SF.sub.6. The polymer layer, formed during the Cl.sub.2 pre-etch, reduces the lateral recessing of the photoresist when the Si.sub.3 N.sub.4 is etched, and results in improved patterned Si.sub.3 N.sub.4 profiles with reduced CD bias, and minimizes Si.sub.3 N.sub.4 footings at the bottom edge of the Si.sub.3 N.sub.4 pattern.

Growing community of inventors

Singapore, Singapore

Pei Ching Lee