FinFET Isolation Doping for Uniform Fin Recess Etching

Solution Overview

Problem

The challenge in the semiconductor industry is to control the etch rate and uniformity during the fin recess etch process for FinFETs, as high etch rates lead to nonuniform fin heights and increased likelihood of voids in the insulation material, affecting the precision and reliability of FinFET manufacturing.

Innovation Solution

Doping the insulation material with carbon or silicon before the fin recess etch process reduces the etch rate, improving etch uniformity and fin height control, and reducing the likelihood of voids by applying the dopants uniformly across the wafer or selectively using a mask to prevent doping at specific regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a high etch rate is used during the fin recess etch process, then productivity is improved, but manufacturing precision deteriorates due to nonuniform fin heights and void formation

Engineering Contradiction:

Improveetch rateVSAvoidfin height uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The insulation material is doped with carbon or silicon before the fin recess etch process to modify its etch characteristics. This preliminary doping action reduces the etch rate and improves etch uniformity during the subsequent recess etching, preventing nonuniform fin heights and void formation while maintaining acceptable productivity

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The etch rate parameter is modified by changing the chemical composition of the insulation material through doping with carbon or silicon. This parameter change reduces the etch rate and improves etch uniformity, resolving the contradiction between high etch rate and fin height uniformity

Inventive Principle:

Principle #35Parameter changes

2Productivity

If a high etch rate is used during the fin recess etch process, then productivity is improved, but reliability deteriorates due to increased likelihood of voids in insulation material

Engineering Contradiction:

Improveetch rateVSAvoidinsulation material integrity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The insulation material is doped with carbon or silicon before the fin recess etch process to modify its etch characteristics. This preliminary doping action reduces the etch rate and improves etch uniformity during the subsequent recess etching, preventing nonuniform fin heights and void formation while maintaining acceptable productivity

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The etch rate parameter is modified by changing the chemical composition of the insulation material through doping with carbon or silicon. This parameter change reduces the etch rate and improves etch uniformity, resolving the contradiction between high etch rate and fin height uniformity

Inventive Principle:

Principle #35Parameter changes

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 reduced etch rate due to doping enhances fin height precision and uniformity, minimizing voids in the insulation material, thereby improving the overall manufacturing process of FinFETs.

Implementation Method 1

doping the insulation material with carbon or silicon before the fin recess etch process reduces the etch rate

Methodology Applied

Scientific EffectDoping: Dopants

Data Source

PatentUS12125876B2Semiconductor device and method

Publication Date: 2024.10.22 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

FinFET structures and methods of forming the same are disclosed. In a method, a fin is formed on a substrate, an isolation region is formed on opposing sides of the fin. The isolation region is doped with carbon to form a doped region, and a portion of the isolation region is removed to expose a top portion of the fin, wherein the removed portion of the isolation region includes at least a portion of the doped region.