Browse Prior Art Database

Improved Spacer Sidewall Process

IP.com Disclosure Number: IPCOM000044159D
Original Publication Date: 1984-Nov-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Dinklage, JB: AUTHOR [+2]

Abstract

This article describes a process which deposits a relatively thin (less than » the thickness of the chemical vapor deposition (CVD) layer) organic layer (e.g., photoresist) over the CVD film in order to protect the underlying silicon wafer from attack during the reactive ion etch (RIE) etch-back process due to the non-uniformity of the CVD SiO2 film. As shown in Fig. 1, the organic film 11 is deposited by conventional techniques (spin, spray, vapor deposit). It will be conformal and will exhibit a tendency to fill in (flow over) cusps 12. After depositing organic film 11, the wafer 13 is heated to a temperature at which reflow takes place (N 160ŒC for photoresist) to further enhance the fill in of cusps 12 (due to the surface tension of the softened film).

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Improved Spacer Sidewall Process

This article describes a process which deposits a relatively thin (less than » the thickness of the chemical vapor deposition (CVD) layer) organic layer (e.g., photoresist) over the CVD film in order to protect the underlying silicon wafer from attack during the reactive ion etch (RIE) etch-back process due to the non- uniformity of the CVD SiO2 film. As shown in Fig. 1, the organic film 11 is deposited by conventional techniques (spin, spray, vapor deposit). It will be conformal and will exhibit a tendency to fill in (flow over) cusps 12. After depositing organic film 11, the wafer 13 is heated to a temperature at which reflow takes place (N 160OEC for photoresist) to further enhance the fill in of cusps 12 (due to the surface tension of the softened film). A RIE etch-back process is chosen which gives approximately equal etch rates for the CVD oxide 14 and the organic film 11. After the resist strip (Fig. 2), the sidewall spacer 15 will be left. Attack of the underlying Si 13 is prevented while retaining the control of the sidewall spacer thickness which is inherent in the CVD etch-back low- doped drain (LDD) process. Slight rounding of the top edges of the gate 16 will likely result. This provides a better profile for subsequent metal films to cover. A slight tail 17 of sidewall spacer 15 at the bottom will likely result. This will have a secondary effect on the shape of the heavy source-drain implant, which will have only a se...