SiOCl Spacer Protection Layer for Sidewall Footing Control

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Solution Overview

Problem

Conventional spacer etch processes in semiconductor manufacturing produce unacceptable results in terms of sidewall spacer footing, substrate recess depth, sidewall spacer critical dimension slimming, and spacer top recess, leading to excessive CD reduction, substrate recess, and capping material consumption.

Innovation Solution

A method involving the deposition of a SiOCl-containing layer as a spacer protection layer, followed by selective and anisotropic etching to partially remove the spacer material from the capping region and substrate, while retaining a sidewall spacer, using a plasma etching process with specific process conditions to control etch resistance and precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional spacer etch processes are used, then the spacer material is removed from the gate structure and substrate, but excessive sidewall spacer footing, substrate recess, and CD slimming occur

Engineering Contradiction:

Improvesidewall spacer critical dimensionVSAvoidspacer material removal

Core Design Contradiction:

Manufacturing precisionVSLoss of substance

Solution Approach 1:

A protection layer is deposited on the spacer material before the etch process to prevent excessive removal. This preliminary protective action ensures that the spacer material is selectively removed only from intended regions (capping and substrate) while preserving the sidewall spacer footing and critical dimensions.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The protection layer is applied selectively to specific regions (capping and substrate areas) rather than uniformly across all spacer surfaces. This localized protection enables differential etching behavior, allowing removal of spacer material from horizontal surfaces while maintaining vertical sidewall spacers with precise dimensions.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If conventional spacer etch processes are used, then the spacer material is removed, but unacceptable substrate recess depth is produced

Engineering Contradiction:

Improvesubstrate recess depthVSAvoidsubstrate material removal

Core Design Contradiction:

Manufacturing precisionVSLoss of substance

Solution Approach 1:

The protection layer is deposited on the spacer material prior to etching, creating a barrier that prevents the etch process from excessively removing substrate material. This preliminary protective measure controls the depth of substrate recess by limiting the etch process to removing only the spacer material while preserving the underlying substrate.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The protection layer acts as an intermediary between the etch process and the substrate material. It mediates the interaction by allowing the etch to remove spacer material while blocking direct etching of the substrate, thereby controlling substrate recess depth to acceptable levels.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If conventional spacer etch processes are used, then the spacer material is removed, but excessive capping material consumption occurs

Engineering Contradiction:

Improvecapping material preservationVSAvoidcapping material removal

Core Design Contradiction:

Manufacturing precisionVSLoss of substance

Solution Approach 1:

The protection layer is deposited on the spacer material before the etch process, creating a protective barrier that prevents excessive removal of capping material. This preliminary action ensures that the etch process selectively removes spacer material while preserving the overlying capping layer.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The protection layer serves as an intermediary that shields the capping material from direct exposure to the etch process. It allows the etch to proceed through the spacer material while blocking the removal of capping material, thereby reducing capping material consumption to acceptable levels.

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method achieves reduced sidewall spacer footing, substrate recess, and capping material consumption, with minimal CD reduction, resulting in improved precision and control over spacer etch process metrics.

Implementation Method 1

depositing a SiOCl-containing layer on an exposed surface of the spacer material to form a spacer protection layer

Methodology Applied

Scientific EffectChemical Vapor Deposition: Chemical Vapour Deposition

Implementation Method 2

performing one or more etching processes to selectively and anisotropically remove the spacer protection layer and the spacer material

Methodology Applied

Scientific EffectPlasma Etching: Plasma

Data Source

PatentUS8809194B2Formation of SiOCl-containing layer on spacer sidewalls to prevent CD loss during spacer etch

Publication Date: 2014.08.19 TOKYO ELECTRON LTD

AI summary

A method for performing a spacer etch process is described. The method includes conformally applying a spacer material over a gate structure on a substrate, and performing a spacer etch process sequence to partially remove the spacer material from the gate structure and the substrate, while retaining a sidewall spacer positioned along a sidewall of the gate structure. The spacer etch process sequence may include depositing a SiOCl-containing layer on an exposed surface of the spacer material to form a spacer protection layer.