Plasma Etch Chamber Sputtering for Hard Mask Selectivity
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Solution Overview
Problem
The semiconductor industry faces challenges in achieving accurate and precise plasma processing for high aspect ratio features in semiconductor devices, particularly in forming conformal features with aspect ratios greater than 20:1, due to limited mask height and etch selectivity of conventional materials, and the deposition and patterning of new materials like metals, metal nitride, and metal carbide are challenging.
Innovation Solution
A plasma etching system with a metal-containing chamber part, such as a refractory metal, is used to sputter metal onto a hard mask, forming a passivation layer that enhances etch selectivity, utilizing systems like CCP and ICP processing with controlled plasma conditions to balance etching and deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional plasma etching is used for high aspect ratio features, then the etching process can be performed, but etch selectivity is insufficient and hard mask consumption is excessive
Solution Approach 1:
A metal passivation layer is deposited onto the hard mask layer before the etching process begins. This preliminary deposition creates a protective barrier that prevents the hard mask from being consumed during etching, allowing the etch process to proceed with high selectivity against the underlying layer while preserving the hard mask structure.
Solution Approach 2:
The metal passivation layer acts as an intermediary between the plasma etch process and the hard mask layer. It provides the necessary protection and selectivity enhancement without requiring modification of the hard mask material itself, enabling conventional hard masks to achieve high aspect ratio etching performance.
2Manufacturing precision
If metal materials are deposited and patterned to enhance etch selectivity, then etch selectivity improves, but the deposition and patterning processes become complex and challenging
Solution Approach 1:
The metal passivation layer deposition is merged with the existing hard mask formation process. The metal layer is deposited conformally over the patterned hard mask, combining the protective function with the existing process flow rather than requiring separate deposition and patterning steps for the metal material.
Solution Approach 2:
The invention changes the physical and chemical parameters of the etch process by introducing metal species into the plasma environment. This is achieved by sputtering metal from the chamber walls or introducing metal-containing gases, which modifies the plasma composition and enhances etch selectivity without requiring complex additional processing steps.
3Manufacturing precision
If new materials like metals, metal nitride, and metal carbide are used to form high aspect ratio features, then etch selectivity improves, but deposition and patterning become difficult
Solution Approach 1:
The metal passivation layer is designed as a thin, sacrificial layer that provides temporary protection during the etch process. It is deposited in a thin conformal layer that is sufficient to enhance selectivity but can be easily removed or is consumed during the process, avoiding the need for complex thick metal deposition and patterning.
Solution Approach 2:
Instead of changing the hard mask material to exotic materials like metal carbide, the invention changes the plasma process parameters by introducing metal species into the etch environment. This modifies the chemical reactions at the etch front, providing the necessary selectivity enhancement while keeping the manufacturing process simple and using conventional materials.
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 improves etch selectivity and reduces hard mask consumption by integrating metal sputtering, enabling efficient fabrication of high aspect ratio features in 3D semiconductor devices with minimal additional processing steps and using conventional process gases.
Implementation Method 1
exposing the surface of the chamber part to the plasma to sputter the refractory metal from the surface of the chamber part
Implementation Method 2
applying a source power to the first electrode of the plasma etch chamber to generate a plasma in the plasma etch chamber
Data Source
AI summary
A method of processing a substrate that includes: loading the substrate into a plasma etch chamber, the substrate including a patterned hard mask layer and an underlying layer, the plasma etch chamber including: a chamber part having a surface including a refractory metal; and a first electrode; flowing a process gas into the plasma etch chamber; while flowing the process gas, applying a source power to the first electrode of the plasma etch chamber to generate a plasma in the plasma etch chamber; exposing the surface of the chamber part to the plasma to sputter the refractory metal from the surface of the chamber part; and exposing the substrate to the plasma to deposit the refractory metal onto a portion of the patterned hard mask layer and etch the underlying layer selectively to the patterned hard mask layer.