Remote Plasma Source Etching for SiNx Selectivity
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Solution Overview
Problem
Current etching methods using direct plasma in semiconductor fabrication face limitations in achieving high etch rates and selectivity, often damaging unwanted films and having restricted process windows.
Innovation Solution
The use of a remote plasma source (RPS) generates plasmas in separate chambers and supplies control gases like HBr, HCl, HI, NH3, SiH4, CHF3, and CH2F2 to a process chamber, allowing for precise control of plasma components and improving etch efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If direct plasma technology (CCP or ICP) is used for etching, then the etching process can be performed, but the etch rate is limited and selectivity is poor causing damage to unwanted films
Solution Approach 1:
The plasma generation process is segmented into two separate chambers: a plasma generation chamber where plasma is created, and a process chamber where the actual etching occurs. This segmentation allows the plasma to be generated under optimal conditions for high etch rate while the process chamber maintains conditions suitable for selectivity and minimal damage to unwanted films.
Solution Approach 2:
A remote plasma source acts as an intermediary between the plasma generation system and the substrate. The plasma is generated remotely and then transported to the process chamber, allowing decoupling of plasma generation parameters from etching parameters. This intermediary approach enables independent optimization of etch rate (in plasma generation) and selectivity (in process chamber).
2Productivity
If direct plasma is applied to achieve high etch rate, then productivity increases, but selectivity deteriorates and process window becomes restricted
Solution Approach 1:
The plasma generation and etching processes are segmented into separate chambers, allowing independent optimization. The plasma generation chamber can be operated at high power for maximum etch rate, while the process chamber maintains controlled plasma density for high selectivity and wide process window.
Solution Approach 2:
The invention changes the operational parameters by separating plasma generation from etching. This allows different parameter sets to be used in each chamber: high power and density in plasma generation chamber for productivity, and controlled lower density with precise gas composition in process chamber for manufacturing precision and selectivity.
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 significantly increases the etch rate and selectivity of target films, such as SiNx, while minimizing damage to non-target films like SiO2, by selectively controlling the plasma composition and application.
Implementation Method 1
generating a plasma by supplying a process gas to at least one RPS and applying power to the at least one RPS
Implementation Method 2
etching a first material film including SiNx by supplying the plasma and at least one control gas selected from HBr, HCl, HI, NH3, SiH4, CHF3, and CH2F2 to a process chamber
Data Source
AI summary
An etching method using a remote plasma source (RPS) and a method of fabricating a semiconductor device, the etching method including generating a plasma by supplying a process gas to at least one RPS and applying power to the at least one RPS; and etching a first material film including SiNx by supplying the plasma and at least one control gas selected from HBr, HCl, HI, NH3, SiH4, CHF3, and CH2F2 to a process chamber.