Spacer Oxide Deposition for Sub-30nm Line Width Control
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Solution Overview
Problem
The existing Spacer Defined Double Patterning process faces challenges in achieving uniformity and control of line width reduction below 30 nm due to the difficulty in controlling the photo resist shrink step, leading to potential patterning failures from leaning or collapsing of photo resist lines.
Innovation Solution
Simultaneous trimming and spacer oxide deposition using a Plasma Enhanced Atomic Layer Deposition process, where the first part of trimming is performed in-situ before spacer oxide deposition and the second part is done during deposition, with direct plasma exposure to reduce photo resist footing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a photo resist shrink step is applied prior to spacer material deposition to achieve narrower line widths, then the line width can be reduced to enable smaller pitch patterning, but the uniformity of shrinking becomes difficult to control and patterning failure risk increases due to leaning or collapsing of photo resist lines
Solution Approach 1:
The patent combines the trimming step and spacer oxide deposition step into a single integrated process. The photo resist trimming is performed in-situ within the same chamber where spacer oxide is deposited, eliminating the need for a separate trimming step. This merging of operations ensures that the photo resist lines are trimmed and immediately protected by spacer oxide deposition, preventing leaning or collapsing while achieving precise line width control for sub-30nm pitch patterning
Solution Approach 2:
The spacer oxide deposition is performed as a preliminary protective action immediately after trimming begins. By depositing the spacer oxide material while the photo resist is being trimmed, the process provides structural support to the photo resist lines before they become too narrow and vulnerable to collapse, ensuring uniform shrinking without patterning failure
2Length of moving object
If photo resist lines are trimmed to narrower widths to achieve smaller pitch, then the pitch can be reduced for higher density patterning, but the structural integrity of photo resist lines deteriorates leading to leaning or collapsing
Solution Approach 1:
The spacer oxide deposition serves as a preliminary strengthening action that begins immediately during the trimming process. By depositing the spacer material while the photo resist lines are being narrowed, the process provides structural reinforcement before the lines become too thin to support themselves, preventing leaning or collapsing and maintaining structural integrity throughout the pitch reduction process
Solution Approach 2:
The patent merges the trimming and spacer deposition operations into a single integrated process step. This combination ensures that as photo resist lines are trimmed to narrower widths for higher density patterning, the spacer oxide is simultaneously deposited to provide structural support, preventing integrity loss even at very small pitch dimensions
3Length of moving object
If trimming is performed in a separate step before spacer deposition, then the photo resist can be trimmed to the desired width, but additional process steps and chamber transitions are required increasing process complexity
Solution Approach 1:
The patent merges two separate process steps (photo resist trimming and spacer oxide deposition) into a single integrated operation performed in the same chamber. This eliminates the need for intermediate chamber transitions and separate processing steps, reducing process complexity while maintaining precise line width control
Solution Approach 2:
The single process chamber is designed to perform multiple functions: it can perform photo resist trimming and immediately follow with spacer oxide deposition without requiring chamber evacuation or substrate removal. This multi-functionality reduces process complexity by eliminating the need for separate dedicated trimming and deposition chambers
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 ensures precise control over critical dimension reduction, maintains the structural integrity of photo resist lines, and improves uniformity by decelerating the etching rate as the spacer oxide coverage reaches full coverage, reducing the risk of patterning failures.
Implementation Method 1
an oxide spacer conformal 33 is deposited on the second photo resist template patterns 22a... The deposited spacer oxide film 33 is etched back by RIE (reactive ion etching)... trimming is performed simultaneously with the process of depositing the spacer oxide. The spacer oxide deposition process is a Plasma Enhanced Atomic Layer Deposition process
Implementation Method 2
direct plasma exposure to reduce photo resist footing... a first part of trimming is performed in-situ, immediately before the spacer oxide deposition process in the same chamber in which the spacer oxide deposition is performed whereas a second part of the trimming is performed simultaneously with the process of depositing the spacer oxide
Data Source
AI summary
Semiconductor patterns are formed by performing trimming simultaneously with the process of depositing the spacer oxide. Alternatively, a first part of the trimming is performed in-situ, immediately before the spacer oxide deposition process in the same chamber in which the spacer oxide deposition is performed whereas a second part of the trimming is performed simultaneously with the process of depositing the spacer oxide. Thus, semiconductor patterns are formed reducing PR footing during PR trimming with direct plasma exposure.