Amorphous Carbon Gap Fill Using CO2 Etching to Prevent Pattern Damage
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Solution Overview
Problem
In the semiconductor manufacturing process, the amorphous carbon gap-fill process using PECVD often results in voids due to overhang formation, and the use of oxygen or hydrogen gas for etching can damage the pattern walls, widening the critical dimension.
Innovation Solution
A substrate processing method involving a cyclic deposition-etching process using carbon dioxide as the etching gas, which simultaneously etches the amorphous carbon layer and forms a protective non-volatile carbon compound layer on the pattern walls, reducing void formation and preventing pattern damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If PECVD process is used for gap-fill deposition, then amorphous carbon layer can be deposited, but overhang forms on top of pattern walls causing voids
Solution Approach 1:
The patent implements a cyclic gap-fill process that alternates between deposition steps and etching steps. The deposition step deposits amorphous carbon layer to fill the gap, while the etching step removes the overhang that forms on top of pattern walls. This periodic alternation continues for multiple cycles until the gap is completely filled without significant overhang, resolving the contradiction between achieving complete gap-fill and preventing overhang formation.
2Shape
If oxygen or hydrogen gas is used for etching amorphous carbon layer, then overhang can be removed, but pattern walls are damaged by ion bombardment
Solution Approach 1:
The patent changes the etching gas parameter from conventional oxygen or hydrogen gas to carbon dioxide gas. This parameter change allows the etching process to remove overhang while simultaneously forming a protective non-volatile carbon compound layer on the pattern walls. The carbon dioxide gas reacts with the amorphous carbon to produce this protective layer, which shields the pattern walls from ion bombardment damage while still enabling effective overhang removal.
3Manufacturing precision
If cyclic deposition and etching is performed, then gap-fill completeness improves, but pattern wall damage occurs during etching
Solution Approach 1:
The patent converts the potentially harmful effect of plasma etching into a beneficial outcome by using carbon dioxide gas. The carbon dioxide reacts with amorphous carbon to form a protective non-volatile carbon compound layer on the pattern walls during the etching process. This protective layer actually benefits the pattern walls by preventing ion bombardment damage while still allowing the etching to effectively remove overhang. Thus, the etching process that could potentially harm the pattern walls instead protects them, enabling multiple cyclic steps to be performed without accumulating damage.
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 method effectively reduces the size of voids in the amorphous carbon gap-fill process while protecting the pattern walls from damage, thereby maintaining the fine dimensions required in semiconductor manufacturing.
Implementation Method 1
an etching step of removing an overhang formed at a top of the pattern wall using an etching gas
Implementation Method 2
etching of the amorphous carbon layer and producing of a carbon compound are achieved simultaneously
Implementation Method 3
a pattern wall protective layer is formed on the pattern wall
Implementation Method 4
producing of a carbon compound are achieved simultaneously
Data Source
AI summary
Disclosed is a substrate processing method including a gap-fill process capable of preventing pattern damage. The substrate processing method includes a deposition step of depositing an amorphous carbon layer on a substrate having pattern walls formed thereon, wherein a gap is defined between the pattern walls; an etching step of removing an overhang formed at a top of the pattern wall using an etching gas; and a repeating step of repeating the deposition step and the etching step so as to fill the gap with the amorphous carbon layer, wherein the etching gas used in the etching step contains carbon dioxide.