Cerium-Based Substrate Cleaning Method for Transition Metal Removal

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Solution Overview

Problem

The existing methods for removing transition metal-containing substances from semiconductor substrates are inefficient, leading to excessive cerium impurities remaining on the substrate surface, which can adversely affect semiconductor device performance.

Innovation Solution

A method involving a chemical solution with a cerium compound and a pH adjuster, followed by a rinsing treatment using specific solutions, effectively removes transition metal-containing substances while minimizing cerium retention on the substrate surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a chemical solution containing cerium compound is used to remove transition metal-containing substances, then removal efficiency is improved, but cerium impurities remain on the substrate surface

Engineering Contradiction:

Improveremoval efficiencyVSAvoidcerium impurity level

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The treatment process is divided into two distinct steps: Step A uses a chemical solution containing cerium compound to remove transition metal-containing substances, and Step B uses a rinsing solution to remove cerium impurities. This segmentation allows each step to optimize for its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention extracts and removes the harmful cerium impurities that remain after the removal process. By introducing a rinsing solution in Step B, the cerium residues are selectively extracted from the substrate surface, resolving the contradiction between removal efficiency and impurity levels.

Inventive Principle:

Principle #2Taking out (Extraction)

2Manufacturing precision

If existing removal methods are used, then transition metal-containing substances are removed, but the removal efficiency is insufficient

Engineering Contradiction:

Improvetransition metal removal completenessVSAvoidremoval efficiency

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The invention changes the chemical parameters of the treatment solution by using a cerium compound as the active ingredient and controlling the pH with specific pH adjusters. This parameter change enables highly efficient removal of transition metal-containing substances while allowing for subsequent cerium removal through rinsing.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If cerium compound is used for removal, then removal efficiency increases, but cerium retention on substrate increases

Engineering Contradiction:

Improvesubstance removal efficiencyVSAvoidcerium retention amount

Core Design Contradiction:

ProductivityVSQuantity of substance

Solution Approach 1:

The rinsing solution acts as an intermediary substance that mediates between the cerium-based removal process and the final substrate cleanliness. It facilitates the removal of cerium impurities without interfering with the effectiveness of the transition metal removal process.

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

This approach enables high-efficiency removal of transition metal-containing substances while ensuring low cerium retention, thereby improving semiconductor device performance and manufacturing efficiency.

Implementation Method 1

a step A of removing a transition metal-containing substance on a substrate by using a chemical solution including a cerium compound and one or more pH adjusters

Methodology Applied

Scientific EffectChemical dissolution:

Implementation Method 2

a step B of performing a rinsing treatment on the substrate obtained by the step A by using one or more rinsing solutions

Methodology Applied

Scientific EffectRinsing:

Data Source

PatentUS11239093B2Method for treating substrate, method for manufacturing semiconductor device, and kit for treating substrate

Publication Date: 2022.02.01 FUJIFILM CORP

AI summary

The present invention provides a method for treating a substrate, which can remove transition metal-containing substances on a substrate with high efficiency while inhibiting cerium from remaining on the surface of the treated substrate. Furthermore, the present invention provides a method for manufacturing a semiconductor device including the method for treating a substrate, and a kit for treating a substrate that is applicable to the method for treating a substrate. The method for treating a substrate according to an embodiment of the present invention includes a step A of removing a transition metal-containing substance on a substrate by using a chemical solution, which includes a cerium compound and one or more pH adjusters selected from the group consisting of nitric acid, perchloric acid, ammonia, and sulfuric acid, for the substrate having the transition metal-containing substance, and a step B of performing a rinsing treatment on the substrate obtained by the step A by using one or more rinsing solutions selected from the group consisting of a solution including hydrogen peroxide and an acidic aqueous solution which is other than hydrofluoric acid, nitric acid, an aqueous perchloric acid solution, an aqueous oxalic acid solution, and a mixed aqueous solution of these and does not include hydrogen peroxide after the step A.