Memory Hole Etching with Silylation to Suppress Bowing
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Solution Overview
Problem
The challenge in semiconductor manufacturing is forming high-aspect-ratio memory holes with a bowing shape during the etching process, which is exacerbated by the disappearance of protective films on the sidewalls, leading to widened hole diameters and reduced process accuracy.
Innovation Solution
A manufacturing method involving alternating reactive ion etching and silylation agent treatments forms protective films on the sidewalls of memory holes, ensuring uniform thickness and preventing sidewall etching, using trimethylsilyldimethylamine (TMSDMA) as a silylation agent to maintain the shape and aspect ratio of the holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If reactive ion etching is performed to form high-aspect-ratio memory holes, then etching depth and aspect ratio are improved, but protective films on sidewalls disappear causing hole diameter to widen and shape accuracy to deteriorate
Solution Approach 1:
The patent applies periodic action by alternating between etching steps and silylation treatment steps. The etching step removes material to deepen the hole, while the silylation step periodically replenishes the protective film on sidewalls. This periodic alternation allows continuous etching at high aspect ratios while maintaining sidewall protection to prevent bowing and diameter widening.
Solution Approach 2:
The silylation treatment is performed as a preliminary action before the protective film completely disappears during etching. By applying the silylation agent at intervals, the protective film is replenished in advance, preventing the sidewall from becoming vulnerable to etching-induced widening and bowing.
2Manufacturing precision
If alternating etching and silylation treatment is performed to maintain protective films, then hole shape accuracy is improved, but manufacturing time increases
Solution Approach 1:
The patent merges the etching process and silylation treatment process into a single integrated chamber. This eliminates the need to transfer wafers between separate etching and silylation equipment, removing transport time and handling steps. The alternating treatments are performed sequentially in the same chamber, maintaining precision while reducing overall manufacturing time.
3Manufacturing precision
If multiple alternating treatments are performed to maintain protective films throughout deep etching, then process accuracy is maintained, but treatment complexity increases
Solution Approach 1:
The single chamber is designed to perform multiple functions: it can conduct reactive ion etching, perform silylation treatment, and facilitate wafer handling. This multi-functionality allows the same equipment to execute the alternating sequence of etching and treatment steps without requiring separate specialized devices, thereby reducing overall system complexity while maintaining process accuracy.
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 method effectively suppresses the bowing shape of memory holes, maintaining high process accuracy and aspect ratios, while reducing manufacturing time and costs by continuously performing etching and treatments in the same chamber.
Implementation Method 1
performing a first treatment of supplying a silylation agent to the recess after the performing the first etching
Implementation Method 2
performing first etching for forming a recess in a layer to be processed using a reactive ion etching method
Data Source
AI summary
A manufacturing method for a semiconductor device according to an embodiment includes performing first etching for forming a recess in a layer to be processed using a reactive ion etching method, performing a first treatment of supplying a silylation agent to the recess after the first etching, and performing second etching of etching at least a bottom surface of the recess using a reactive ion etching method after the first treatment.