Polyurea Protective Layer for Semiconductor Film Integrity
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Solution Overview
Problem
In semiconductor device manufacturing, porous low dielectric constant films like SiOC films are damaged during plasma treatments due to broken Si—C bonds, leading to instability and potential oxidation, and existing protective techniques like PMMA are ineffective at high temperatures, causing thermal instability and damage to already formed elements.
Innovation Solution
A method involving the formation of a protective layer made of polyurea with urea bonds by self-polymerization using isocyanate and water, which is sealed with a polyimide film at a lower temperature, allowing the substrate to withstand higher temperature processes without depolymerizing, thus protecting the film from damage during plasma treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective layer made of PMMA is used to protect the low dielectric constant film during plasma treatment, then the film damage is suppressed, but the substrate must be heated to 400°C or higher for removal, which adversely affects already formed element portions
Solution Approach 1:
The patent changes the chemical composition parameter of the protective layer from PMMA to polyurea containing Si—C bonds. This parameter change enables the protective layer to withstand plasma treatment while allowing removal at lower temperatures (below 400°C) that do not damage already formed element portions
Solution Approach 2:
The patent uses a composite protective layer made of polyurea with Si—C bonds, combining the protective properties needed for plasma treatment with thermal stability characteristics that allow low-temperature removal, thus resolving the contradiction between protection during processing and safe removal
2Ease of manufacture
If the substrate is heated to high temperature to remove the protective layer, then the protective layer is effectively removed, but already formed element portions in the substrate are adversely affected
Solution Approach 1:
The patent changes the thermal decomposition temperature parameter of the protective layer by selecting polyurea with Si—C bonds as the material. This enables effective removal at temperatures below 400°C, protecting already formed element portions while still achieving complete protective layer removal
3Productivity
If a plasma treatment is performed on the porous low dielectric constant film to embed wiring, then the wiring embedding is achieved, but the Si—C bonds in the film are broken causing film damage
Solution Approach 1:
The patent applies preliminary action by forming a protective layer of polyurea with Si—C bonds on the porous low dielectric constant film before plasma treatment. This protective layer prevents Si—C bond breaking during plasma treatment while allowing the plasma treatment to proceed for wiring embedding
Solution Approach 2:
The protective layer acts as an intermediary between the plasma treatment and the porous low dielectric constant film. It absorbs the harmful effects of plasma treatment, preventing direct damage to the Si—C bonds in the film while allowing the plasma treatment to achieve wiring embedding
4Temperature
If the protective layer is exposed to high temperature during processing, then the processing can be performed, but the polymer depolymerizes and loses its protective function
Solution Approach 1:
The patent changes the thermal stability parameter of the polymer protective layer by selecting polyurea containing Si—C bonds. This parameter change enables the protective layer to maintain its protective function at processing temperatures up to 400°C without depolymerization, while still allowing removal at controlled lower temperatures
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 polyurea protective layer effectively suppresses damage to low dielectric constant films during plasma treatments and high-temperature processes, maintaining the integrity of the film and preventing oxidation, while allowing for efficient removal without affecting pre-formed elements.
Implementation Method 1
a second temperature at which the polymer is depolymerized
Implementation Method 2
forming a sealing film at a first temperature lower than a second temperature at which the polymer is depolymerized
Implementation Method 3
subjecting the substrate to a treatment at a third temperature equal to or higher than the second temperature
Data Source
AI summary
A method of manufacturing a semiconductor device by performing a process on a substrate includes: forming a protective layer made of a polymer having a urea bond by supplying a raw material for polymerization to a surface of a substrate on which a protected film to be protected is formed; forming a sealing film at a first temperature lower than a second temperature at which the polymer is depolymerized so cover a portion where the protective layer is exposed; subsequently, subjecting the substrate to a treatment at a third temperature equal to or higher than the second temperature at which the polymer as the protective layer is depolymerized; subsequently, performing a treatment which causes damage to the protected film when the protective layer is not present; and after the performing a treatment which causes damage to the protected film, depolymerizing the polymer by heating the substrate.