Silicon Plasma Etching Gas Chemistry for Mask Opening Integrity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing etching methods for silicon films often result in shape abnormalities due to the formation of protective films that block or narrow the openings in the mask, leading to uneven etching and reduced etching selectivity.
Innovation Solution
An etching method using a processing gas mixture of bromine-containing, phosphorus fluoride, and oxygen-containing gases to generate plasma, which includes controlling the flow rates of these gases to prevent the formation of excessive protective films, thereby maintaining the integrity of the mask openings and promoting uniform etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching methods are used to etch silicon films, then etching can be performed, but protective films form that block or narrow mask openings causing shape abnormalities
Solution Approach 1:
The patent applies parameter changes by carefully controlling the flow rates of processing gases (bromine-containing gas, phosphorus fluoride gas, and oxygen-containing gas) to adjust the chemical composition and properties of the etching plasma. This prevents excessive protective film formation while maintaining etching selectivity and precision
Solution Approach 2:
The patent converts the harmful protective film formation into a beneficial effect by using controlled protective film formation to protect sidewalls from over-etching, while preventing blockage of mask openings through optimized gas composition and flow rates
2Strength
If protective films are formed during etching, then sidewall protection is improved, but mask openings become blocked or narrowed reducing etching uniformity
Solution Approach 1:
The patent applies local quality by creating different protective film characteristics at different locations: sufficient protection on sidewalls while preventing film accumulation that would block mask openings. This is achieved through optimized plasma chemistry and flow rate control
Solution Approach 2:
The patent changes physical and chemical parameters including gas flow rates, pressure, and temperature to control protective film formation locally, ensuring sidewall protection without compromising mask opening integrity
3Productivity
If etching is performed with conventional methods, then material removal is achieved, but etching selectivity decreases due to protective film interference
Solution Approach 1:
The patent uses a composite processing gas mixture containing bromine-containing gas, phosphorus fluoride gas, and oxygen-containing gas in specific proportions. This composite gas composition enables simultaneous achievement of high etching rate and high selectivity by balancing protective film formation and removal
Solution Approach 2:
The patent optimizes etching selectivity and productivity by adjusting parameters including gas flow rates, pressure, and power settings to control the balance between protective film formation and etching reactions
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
Prevents shape abnormalities and improves etching selectivity by effectively removing protective films near mask openings, ensuring consistent etching depth and width dimensions.
Implementation Method 1
supplying, into the chamber, a processing gas that contains a bromine containing gas, a phosphorus fluoride gas, and an oxygen containing gas, and generating a plasma from the processing gas to etch the silicon film or the silicon-containing conductive film
Implementation Method 2
generating a plasma from the processing gas to etch the silicon film or the silicon-containing conductive film
Data Source
AI summary
To provide a technique of preventing shape abnormalities due to etching of a silicon film. An etching method includes: (a) providing, on a substrate support disposed in a chamber, a substrate that includes a silicon film or a silicon-containing conductive film and a mask on the silicon film or the silicon-containing conductive film, and (b) supplying, into the chamber, a processing gas that contains a bromine containing gas, a phosphorus fluoride gas, and an oxygen containing gas, and generating a plasma from the processing gas to etch the silicon film or the silicon-containing conductive film.