Substrate Patterning With Sacrificial Film Metal Residue Removal
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Solution Overview
Problem
In semiconductor manufacturing, metal components from metal-containing resist films remain at the bottom of patterns, forming compounds that inhibit etching and cause defects such as bridges, and are difficult to remove using conventional methods.
Innovation Solution
A method involving the formation of a sacrificial film under the resist film, followed by exposure and development, and subsequent removal of the sacrificial film's surface layer facing the resist pattern bottom to eliminate remaining metal components, either through chemical dissolution or UV irradiation and heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a metal-containing resist film is used for high-contrast patterning, then imaging contrast is improved, but metal components remain at the pattern bottom causing etching defects
Solution Approach 1:
A sacrificial film is introduced as an intermediary layer between the substrate and the metal-containing resist film. This sacrificial film serves as a mediator that temporarily holds the metal components during processing, preventing them from adhering to the pattern bottom and causing defects. The sacrificial film is designed to be removed selectively after serving its protective function.
Solution Approach 2:
The sacrificial film is applied in advance before the metal-containing resist film is formed. This preliminary action prepares the surface to prevent metal component adhesion issues before they occur during the patterning process, rather than attempting to remove them after the fact.
2Object-generated harmful factors
If conventional acid treatment is used to remove metal components, then some metal removal is achieved, but the pattern is damaged
Solution Approach 1:
The sacrificial film acts as a protective intermediary that absorbs the impact of aggressive removal treatments. By directing the removal action toward the sacrificial film rather than the pattern itself, the pattern integrity is preserved while still achieving metal component removal through the sacrificial film's selective dissolution.
Solution Approach 2:
The sacrificial film is designed as a temporary, disposable layer that is intentionally removed after serving its protective function. This disposable approach allows for aggressive metal removal treatments to be applied safely, knowing the sacrificial film will be discarded afterward, protecting the valuable pattern.
3Ease of operation
If the sacrificial film is made soluble in developing solution for easy removal, then removal ease is improved, but the resist pattern cannot be properly formed
Solution Approach 1:
The sacrificial film is designed with spatially varying properties: it has low solubility in the developing solution in regions where resist pattern formation occurs, but high solubility in specific removal regions where metal component removal is needed. This local differentiation allows both resist pattern formation and subsequent metal removal to proceed effectively.
Solution Approach 2:
The solubility parameters of the sacrificial film are carefully controlled and differentiated. The film exhibits different solubility characteristics toward different chemical solutions (developing solution versus removal solution), allowing selective removal at different stages of the process without interfering with resist pattern formation.
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
Effectively suppresses metal component adhesion at the pattern bottom, preventing etching defects and ensuring clean etching processes.
Implementation Method 1
removing at least a surface layer portion of the sacrificial film facing a bottom of the resist pattern to remove remaining metal components
Implementation Method 2
cross-linking the resist film by irradiating the surface of the substrate with ultraviolet rays
Implementation Method 3
removing at least a surface layer of the sacrificial film facing a bottom of the resist pattern by heating the substrate, to remove remaining metal components
Data Source
AI summary
A technique for suppressing a metal component from remaining at a bottom of a mask pattern when the mask pattern is formed using a metal-containing resist film. A developable anti reflection film 103 is previously formed below a resist film 104. Further, after exposing and developing the wafer W, TMAH is supplied to the wafer W to remove a surface of the anti-reflection film 103 facing a bottom of the recess pattern 110 of the resist film 104. Therefore, the metal component 105 can be suppressed from remaining at the bottom of the recess pattern 110. Therefore, when the SiO2 film 102 is subsequently etched using the pattern of the resist film 104, the etching is not hindered, so that defects such as bridges can be suppressed.