Substrate Treatment Selectivity via Silylation and Etching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current substrate treatment methods for semiconductor and liquid crystal display devices face challenges in achieving high selectivity during the selective etching of silicon nitride and silicon oxide films, as existing etching processes often result in reduced selectivity and contamination due to the reactivity of etching agents with the substrate surfaces.
Innovation Solution
A substrate treatment method involving a silylation step followed by an etching step, where a silylation agent is applied to the substrate before etching, suppressing oxide film etching and improving nitride removal selectivity. This method includes repeating cycles of silylation and etching, UV irradiation, and the use of non-aqueous silylation agents to maintain selectivity and cleanliness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching processes are used to remove silicon nitride film, then etching can be performed, but selectivity between nitride and oxide removal is reduced
Solution Approach 1:
A silylation treatment is performed on the substrate before etching to form a silylated layer on the oxide film surface. This preliminary action modifies the oxide film surface properties to reduce its reactivity with the etching liquid, thereby suppressing oxide film removal during the subsequent etching process and improving selectivity between nitride and oxide removal.
Solution Approach 2:
The silylation agent acts as an intermediary substance that forms a protective silylated layer on the oxide film surface. This intermediate layer serves as a barrier between the oxide film and the etching liquid, reducing the harmful interaction between the etching agent and the oxide film while allowing selective nitride removal.
2Reliability
If silylation agent activity varies with temperature, then process control becomes difficult, but temperature control adds complexity
Solution Approach 1:
The invention utilizes the temperature dependence of silylation agent activity as a controllable parameter. By adjusting the temperature within a specific range (room temperature to 100°C), the silylation agent activity can be optimized without requiring complex control systems. The etching liquid temperature is controlled within 120°C to 160°C, and the silylation agent is supplied at a temperature that achieves desired activity while simplifying the overall process control.
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 significantly enhances the selectivity of nitride removal over oxide removal, reduces contamination, and maintains the activity of silylation agents, leading to improved substrate cleanliness and process efficiency.
Implementation Method 1
a silylation step of supplying a silylation agent to a substrate... the substrate is silylated by the supply of the silylation agent... where a substrate formed with an oxide film and a nitride film is silylated, etching of the oxide film is suppressed
Implementation Method 2
selective etching for selectively removing the silicon nitride film from the front surface... an etching step of supplying an etching agent to the substrate... the silylated substrate is etched
Implementation Method 3
a UV irradiation step of irradiating the substrate with ultraviolet radiation after the etching step... The silylation agent adhering to the substrate can be removed by the irradiation of the silylated substrate with the ultraviolet radiation
Data Source
AI summary
An inventive substrate treatment method includes a silylation step of supplying a silylation agent to a substrate, and an etching step of supplying an etching agent to the substrate after the silylation step. The method may further include a repeating step of repeating a sequence cycle including the silylation step and the etching step a plurality of times. The cycle may further include a rinsing step of supplying a rinse liquid to the substrate after the etching step. The cycle may further include a UV irradiation step of irradiating the substrate with ultraviolet radiation after the etching step. The method may further include a pre-silylation or post-silylation UV irradiation step of irradiating the substrate with the ultraviolet radiation before or after the silylation step.