Polyurea Protective Film Depolymerization for Semiconductor Substrates

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Solution Overview

Problem

In semiconductor device manufacturing, the removal of sacrificial films and embedded materials can damage metal conductive paths and increase process complexity, leading to reduced productivity and potential device deterioration due to oxidation reactions during plasma treatment.

Innovation Solution

A method involving the formation of a protective polyurea film with urea bonds on a substrate, which is then removed by depolymerization under a low oxygen atmosphere, preventing oxidation and residue formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If plasma treatment is used to remove sacrificial film, then the sacrificial film can be removed, but metal conductive paths may be oxidized and damaged

Engineering Contradiction:

Improvequality of semiconductor deviceVSAvoidoxidation damage to metal conductive paths

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary substance (embedded material such as PMMA or other polymers) that is placed between the sacrificial film and the metal conductive path. This intermediary material serves as a protective barrier during plasma treatment, preventing direct contact between the plasma and the metal conductive path, thereby avoiding oxidation damage while still allowing the sacrificial film to be removed.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs an inert atmosphere (such as nitrogen or argon environment) during the plasma treatment process to prevent oxidation reactions. By creating an inert environment, the harmful oxidizing effect of plasma on metal conductive paths is eliminated, allowing safe removal of sacrificial films and embedded materials without compromising metal integrity.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Reliability

If reduction process is added after sacrificial film removal, then oxidation damage can be prevented, but process time and complexity increase

Engineering Contradiction:

Improvequality of semiconductor deviceVSAvoidproductivity of semiconductor device

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary protective action by embedding protective materials (such as PMMA or other polymers) before performing plasma treatment. This preliminary embedding prevents oxidation damage in advance, eliminating the need for subsequent reduction processes. The protective embedded material remains in place during plasma treatment, preventing oxidation, and can be removed later without requiring additional reduction steps, thus streamlining the overall process.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If high temperature heating is used to remove PMMA, then the embedded material can be removed, but device elements may be adversely affected

Engineering Contradiction:

Improveremoval completeness of embedded materialVSAvoidthermal damage to device elements

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses an inert atmosphere (nitrogen or argon) during the heating process to remove embedded PMMA material. The inert environment prevents oxidation reactions that would otherwise occur at elevated temperatures, allowing the embedded material to be thermally decomposed and removed without oxidizing sensitive device elements. This approach enables effective removal of PMMA while maintaining the integrity of metal conductive paths and other temperature-sensitive components.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

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 effectively protects metal conductive paths from damage, simplifies the removal process, and enhances semiconductor device quality by avoiding residue formation and thermal damage, thus improving productivity.

Implementation Method 1

removing the protective material by heating the substrate under a low oxygen atmosphere to depolymerize the polymer

Methodology Applied

Scientific EffectDepolymerization: Decomposition (biological)

Implementation Method 2

preventing oxidation and residue formation

Methodology Applied

Scientific EffectOxidation prevention: Oxidation

Data Source

PatentUS10840084B2Method of manufacturing semiconductor device and substrate processing apparatus

Publication Date: 2020.11.17 TOKYO ELECTRON LTD

AI summary

A method of manufacturing a semiconductor device includes: forming a protective material composed of a polymer having a urea bond by supplying a raw material for polymerization to a surface of a substrate for manufacturing the semiconductor device, the protective material configured to protect a protection target layer provided in the substrate against a treatment to be performed on the substrate; subsequently performing the process on the substrate on which the protective material is formed; and subsequently removing the protective material by heating the substrate under a low oxygen atmosphere to depolymerize the polymer.