Concurrent Etch and Directional Deposition for Hard Mask Control
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Solution Overview
Problem
Semiconductor fabrication processes face challenges in producing narrow openings in hard masks with accuracy and maintaining critical dimensions due to variations in size and shape, which can be exacerbated by aggressive etching processes, leading to hard mask degradation and undesirable etching results.
Innovation Solution
A system and method utilizing a reactive-ion etching source and dual plasma enhanced chemical vapor deposition sources to etch and deposit materials concurrently, allowing for precise control over hard mask shape and critical dimensions by directing radical beams at specific angles and positions to correct and maintain the mask's shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a longer or more aggressive etching process is used to remove material from the underlying substrate through narrow hard mask openings, then the etching depth and completeness are improved, but the hard mask is removed at an unacceptable rate and its shape is altered in undesirable manners
Solution Approach 1:
A deposition layer is deposited on the hard mask before the etching process to provide preliminary protection. This pre-deposited layer acts as a sacrificial barrier that absorbs the aggressive etching conditions, preventing direct damage to the hard mask structure and maintaining its shape and dimensional integrity throughout the etching process.
Solution Approach 2:
The deposition layer serves as an intermediary between the aggressive ion beam and the hard mask. It absorbs the harmful effects of the etching process, allowing the ion beam to remove substrate material effectively while the hard mask remains protected and maintains its original shape and critical dimensions.
2Reliability
If the hard mask is made thicker to compensate for material removal during aggressive etching, then the protection of underlying substrate is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
Instead of making the hard mask thicker in advance, a deposition layer is applied beforehand to provide the necessary protection. This approach maintains the original hard mask thickness and simple structure while achieving the required protection during etching through the sacrificial deposition layer.
Solution Approach 2:
The protective function is segmented from the hard mask structure itself and assigned to a separate deposition layer. This allows the hard mask to remain simple and thin while the deposition layer provides the necessary protection, avoiding the need to increase hard mask complexity.
3Manufacturing precision
If a different type of material with higher etching resistance is used for the hard mask, then the resistance to aggressive etching is improved, but the manufacturing cost and difficulty increase
Solution Approach 1:
Instead of changing the hard mask material to achieve etching resistance, a deposition layer is introduced as an intermediary that provides the necessary etching resistance. This allows the use of standard, easily fabricated hard mask materials while achieving high etching resistance through the protective deposition layer.
Solution Approach 2:
The etching resistance is not changed by modifying the hard mask material properties but by adding a separate deposition layer with appropriate etching resistance characteristics. This maintains the ease of manufacturing the hard mask while achieving the required protection during aggressive etching.
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 system effectively corrects and maintains the hard mask's shape and critical dimensions, ensuring precise etching of features with desired dimensions, reducing variations and enhancing semiconductor device performance.
Implementation Method 1
An ion beam formed of reactive plasma ions is directed at the hard mask, and the exposed portions of the underlying substrate are etched by the ion beam
Implementation Method 2
a first plasma enhanced chemical vapor deposition (PECVD) source located on a first side of the RIE source, the first PECVD source adapted to produce a first radical beam and to direct the first radical beam into the process chamber for depositing a first material
Data Source
AI summary
An etching and deposition system including a process chamber containing a platen for supporting a substrate, an reactive-ion etching (RIE) source adapted to produce an ion beam and to direct the ion beam into the process chamber for etching the substrate, a first plasma enhanced chemical vapor deposition (PECVD) source located on a first side of the RIE source, the first PECVD source adapted to produce a first radical beam and to direct the first radical beam into the process chamber for depositing a first material, and a second PECVD source located on a second side of the RIE source opposite the first side, the second PECVD source adapted to produce a second radical beam and to direct the second radical beam into the process chamber for depositing a second material.