Carbon Hard Mask CMP for Uniform Gate Trench Recess

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The challenge in integrated circuit fabrication lies in achieving consistent transistor structures with varying gate widths and densities, as current methods like standard carbon hard mask (CHM) etch-back processes fail to uniformity recess the CHM, leading to height variations and subsequent performance and yield issues.

Innovation Solution

A chemical mechanical polishing (CMP) process using a silica-based slurry is employed to polish the carbon hard mask (CHM) to ensure it recesses to a uniform height across different gate trenches and fin densities, facilitating consistent work function layer heights within 2 nm across all devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If standard carbon hard mask etch-back process is used, then processing simplicity is maintained, but height uniformity of CHM across different gate trenches deteriorates

Engineering Contradiction:

Improveprocessing simplicityVSAvoidheight uniformity of CHM

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the etching parameters by introducing a two-step etch-back process with different etchants (first etchant for initial removal, second etchant for precision control) and controlled etch conditions to achieve uniform CHM height across varying trench geometries

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent performs preliminary planarization by depositing an additional CHM layer over regions where CHM needs to be raised, before performing the controlled etch-back process, ensuring all regions reach the same final height

Inventive Principle:

Principle #10Preliminary action

2Productivity

If batch processing is applied to devices with varying sizes and densities, then productivity is improved, but processing uniformity across different devices deteriorates

Engineering Contradiction:

Improvebatch processing efficiencyVSAvoidprocessing uniformity across devices

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies local quality control by using selective masking regions and localized CHM deposition to address specific height variation issues in different device regions while maintaining batch processing, allowing each device type to receive tailored treatment within the same processing run

Inventive Principle:

Principle #3Local quality

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

This approach ensures more consistent transistor performance and yield by maintaining uniform work function layer heights, addressing the issue of height variations caused by trench volume differences and device density variations.

Implementation Method 1

A chemical mechanical polishing (CMP) process using a silica-based slurry is employed to polish the carbon hard mask (CHM)

Methodology Applied

Scientific EffectChemical mechanical polishing:

Data Source

PatentUS20240194732A1Chemical mechanical polishing of carbon hard mask

Publication Date: 2024.06.13 INTEL CORP

AI summary

Techniques are provided herein to use a chemical mechanical polishing (CMP) process to polish carbon hard mask (CHM) for a variety of useful semiconductor fabrication applications. In one example, a CMP process that uses a silica-based slurry is used to polish CHM formed over gate trenches of different widths, such that the CHM can recess to substantially the same height within the gate trenches of different widths. In another example, CHM may be deposited over groups of fins or a backbone structure and polished using a CMP process with a silica-based slurry to ensure a planar top surface of CHM over the groups of fins or backbone structure.