International Business Machines Corporation

Kabushiki Kaisha Toshiba

Siemens Aktiengesellschaft

Stuart M Burns

Hussein Ibrahim Hanafi

Diane Catherine Boyd

William C Wille

Yuan Taur

Waldemar Walter Kocon

Munir D Naeem

Masaki Narita

Virinder Grewal

Bruno Spuler

Richard Stephan Wise

Nancy Anne Greco

Jeffrey John Welser

Ernest N Levine

Michael L Passow

David Angell

Chi-Hua Yang

Rosemary Christie

Steve Greco

Walter W Kocon

Field effect transistors with vertical gate side walls and method for making such transistors

A process and etchant gas composition for anisotropically etching a trench in a silicon nitride layer of a multilayer structure. The etchant gas composition has an etchant gas including a polymerizing agent, a hydrogen source, an oxidant, and a noble gas diluent. The oxidant preferably includes a carbon-containing oxidant component and an oxidant-noble gas component. The fluorocarbon gas is selected from CF , C F , and C F ; the hydrogen source is selected from CHF , CH F , CH F, and H ; the oxidant is selected from CO, CO , and O ; and the noble gas diluent is selected from He, Ar, and Ne. The constituents are added in amounts to achieve an etchant gas having a high nitride selectivity to silicon oxide and photoresist. A power source, such as an RF power source, is applied to the structure to control the directionality of the high density plasma formed by exciting the etchant gas. The power source that controls the directionality of the plasma is decoupled from the power source used to excite the etchant gas. The etchant gas can be used during a nitride etch step in a process for making a metal oxide semiconductor field effect transistor.

Anisotropic nitride etch process with high selectivity to oxide and photoresist layers in a damascene etch scheme

A process for estimating a critical dimension of a trench formed by etching a substrate. First, a regression model is constructed for estimating the critical dimension, in which principal component loadings and principal component scores are also calculated. Next, a substrate is etched and spectral data of the etching are collected. A new principal component score is then calculated using the spectral data and the principal component loadings. Finally, the critical dimension of the trench is estimated by applying the new principal component score to the regression model.

Reactive ion etch loading measurement technique

A method of fabricating MOSFET devices in which the gate polysilicon is not consumed during damascene etch back, comprising: (a) forming a gate stack on a surface of a silicon-containing substrate, said gate stack having at least a pad oxide layer formed on said surface of said silicon-containing substrate and a nitride layer formed on said pad oxide layer; (b) forming a trough in said gate stack stopping on said pad oxide layer exposing a portion of said pad oxide layer, said trough having vertical sidewalls; (c) forming a conformal silicon layer on said gate stack and in said trough, including said vertical sidewalls and said exposed pad oxide layer; (d) removing the conformal silicon layer from said gate stack and said exposed pad oxide layer whereby silicon remains on the vertical sidewalls of said trough; (e) removing the exposed pad oxide from said trough exposing a portion of the silicon-containing substrate; (f) oxidizing the silicon on said vertical sidewalls of the trough and in said exposed silicon-containing substrate forming oxide layers in said vertical sidewalls and on said exposed silicon-containing substrate; (g) forming doped polysilicon in said trough; (h) performing a second oxidation step in which an oxide layer is formed on a top surface of said doped polysilicon; (i) removing the remaining nitride layer of the gate stack forming a gate region which is protected on all sides by oxides; and (j) forming source and drain regions in said silicon-containing substrate.

Sacrificial silicon sidewall for damascene gate formation

Metal oxide semiconductor field effect transistor (MOSFET) including a drain region and a source region adjacent to a channel region. A gate oxide is situated on the channel region and a gate conductor with vertical side walls is placed on the gate oxide. The MOSFET further includes a threshold adjust implant region and/or punch through implant region being aligned with respect to the gate conductor and limited to an area underneath the gate conductor. Such a MOSFET can be made using the following method: forming a dielectric stack on a semiconductor structure; defining an etch window on the dielectric stack having the lateral size and shape of a gate hole to be formed; defining the gate hole in the dielectric stack by transferring the etch window into the dielectric stack using a reactive ion etching (RIE) process; implanting threshold adjust dopants and/or punch through dopants through the gate hole; depositing a gate conductor such that it fills the gate hole; removing the gate conductor covering portions of the semiconductor structure surrounding the gate hole; and removing at least part of the dielectric stack.

Field effect transistors with improved implants and method for making

A method for the formation of field effect transistors (FETs), and more particularly metal oxide field effect transistors (MOSFETs), comprising the steps of: forming a dielectric stack on a semiconductor structure; defining an etch window on the dielectric stack; defining a gate hole in the dielectric stack by transferring the etch window into the dielectric stack using a reactive ion etching (RIE) process; depositing a side wall layer; removing the side wall layer from horizontal surfaces of the dielectric stack and gate hole such that side wall spacers remain which reduce the lateral size of the gate hole; depositing a gate conductor such that it fills the gate hole; removing the gate conductor covering the portions of the semiconductor structure surrounding the gate hole; removing at least part of the dielectric stack; and removing the side wall spacers.

Method for making field effect transistors having sub-lithographic gates

RIE of metallization is achieved at low power and low pressure using Cl.sub.2 and HCl as reactant species by creating a transformer coupled plasma with power applied to electrodes positioned both above and below a substrate with metallization thereon to be etched. Three layer metallizations which include bulk aluminum or aluminum alloy sandwiched between barrier layers made from, for example, Ti/TiN, are etched in a three step process wherein relatively lower quantities of Cl.sub.2 are used in the plasma during etching of the barrier layers and relatively higher quantities of Cl.sub.2 are used during etching of the bulk aluminum or aluminum alloy layer. The ratio of etchants Cl.sub.2 and HCl and an inert gas, such as N.sub.2 are controlled in a manner such that a very thin side wall layer (10-100 .ANG.) of reaction byproducts created during RIE are deposited on the side walls of trenches formed in the metallization during etching. The side wall layer improves the isotropic nature of the etch such that submicron metallization lines with defect free side walls are formed. Hydrogen (H.sub.2) can be added to the plasma and will act to reduce corrosion.

Low pressure and low power C1.sub.2 /HC1 process for sub-micron metal

Decoupled plasma etching process used to make a protruding structure having vertical or near vertical sidewalls. The decoupled plasma etching process comprises the following steps:

Silicon sidewall etching

A method in a plasma processing chamber for etching through a selected portion of a layer stack. The layer stack comprises a metallization layer, a first barrier layer disposed adjacent to the metallization layer, and a photoresist layer disposed above the metallization layer. The method includes etching at least partially through the first barrier layer using a high sputter component etch. The method further includes etching at least partially through the metallization layer using a low sputter component etch. The low sputter component etch has a sputter component lower than a sputter component of the high sputter component etch.

Methods for metal etching with reduced sidewall build up during

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Stuart M Burns