Urea Polymer Mask Depolymerization for Ion Implantation
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Solution Overview
Problem
In semiconductor device manufacturing, the formation of a carbonized layer during ion implantation can lead to damage to the substrate and the generation of particles, especially with the miniaturization of semiconductor devices, as existing methods for removing the resist film often damage the ion implantation region and result in inefficient processing due to the need to transfer substrates between vacuum and atmospheric pressure environments.
Innovation Solution
A method involving the formation of a first mask film composed of a polymer with a urea bond and a second inorganic mask film, which are laminated and patterned for ion implantation, followed by the removal of the inorganic film and subsequent heating to depolymerize the polymer mask, thereby preventing the formation of a carbonized layer and reducing substrate damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a resist film is used as a mask for ion implantation, then the mask can be formed easily, but a carbonized layer is formed on the substrate surface during ion implantation causing damage and particle generation
Solution Approach 1:
An inorganic film is introduced as an intermediary layer between the resist film and the substrate. This inorganic film serves as a protective barrier that prevents carbonized layer formation on the substrate during ion implantation, while allowing the resist film to remain as the primary mask material for easy pattern formation.
Solution Approach 2:
The mask structure is changed from a single resist film to a composite structure consisting of an inorganic film layer and a resist film layer. This composite mask combines the protective properties of the inorganic film with the easy-to-form patterns of the resist film, resolving the contradiction between ease of manufacture and prevention of substrate damage.
2Ease of repair
If traditional methods are used to remove the carbonized layer and resist film, then the mask can be removed, but the ion implantation region is damaged and particles are generated
Solution Approach 1:
The inorganic film is selectively removed (taken out) from the mask structure after ion implantation, leaving the resist film intact for subsequent removal. This selective extraction allows the resist film to be removed using gentle processes that do not damage the ion implantation region, as the harmful carbonized layer is prevented from forming in the first place.
3Ease of operation
If a silicon-containing film is used as a mask for ion implantation, then the mask can be removed by dipping in mask stripping solution, but the substrate must be transferred from vacuum to atmospheric pressure increasing steps and cost
Solution Approach 1:
The mask removal process is performed within the vacuum atmosphere using an inert gas environment. The mask stripping solution is introduced into the vacuum chamber, allowing the substrate to remain in the vacuum environment throughout the removal process. This eliminates the need for substrate transfer between vacuum and atmospheric pressure environments, reducing process steps and maintaining process efficiency.
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 prevents substrate damage and particle generation by avoiding the harsh environments required for traditional carbonized layer removal, enhancing the reliability of semiconductor devices and improving processing efficiency by maintaining the ion implantation process within a vacuum atmosphere.
Implementation Method 1
removing the first mask film by heating the substrate after the ion implantation and depolymerizing the polymer
Implementation Method 2
an ion implantation module configured to implant, in a vacuum atmosphere, ions into a substrate in which a first mask film composed of a polymer having a urea bond and a second mask inorganic film laminated on the first mask film are formed and in which a mask pattern is formed on each of the first mask film and the second mask inorganic film
Implementation Method 3
an etching processing module configured to supply an etching gas to the substrate to remove the second mask inorganic film in the vacuum atmosphere after the ion implantation
Data Source
AI summary
There is provided a semiconductor device manufacturing method including: forming a first mask film composed of a polymer having a urea bond by supplying a raw material to a surface of the substrate for polymerization; forming a second mask inorganic film to be laminated on the first mask film; forming a pattern on the first mask film and the second mask inorganic film and performing an ion implantation on the surface of the substrate; removing the second mask inorganic film after the ion implantation; and removing the first mask film by heating the substrate after the ion implantation and depolymerizing the polymer.