FinFET Oxide Surface Protection During HF Residue Cleaning
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Solution Overview
Problem
The existing methods for forming fin-type and complementary-type field-effect transistors face challenges due to damage and residue contamination on oxide surfaces during the dry etching and subsequent cleaning processes, particularly with hydrogen fluoride solutions.
Innovation Solution
The use of a silane compound to protect oxide surfaces during the cleaning process with hydrogen fluoride, allowing for efficient removal of residues without further damaging the oxide surfaces, even with high concentrations of hydrogen fluoride.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If hydrogen fluoride solution is used to clean oxide surfaces after dry etching, then oxide-like residues are removed, but oxide surfaces become damaged
Solution Approach 1:
A silane-based protective coating is applied as an intermediary layer between the hydrogen fluoride cleaning solution and the oxide surfaces. This coating selectively protects the oxide surfaces from HF damage while allowing the cleaning solution to effectively remove organic residues. The protective coating acts as a mediator that enables the cleaning process without causing surface damage.
Solution Approach 2:
The silane-based protective coating is applied beforehand to prevent damage to oxide surfaces before the hydrogen fluoride cleaning step. This preliminary protective action creates a barrier that prevents the harmful interaction between HF and oxide surfaces, allowing subsequent removal of the protective coating to reveal clean, undamaged oxide surfaces.
2Reliability
If low concentration of hydrogen fluoride is used to prevent oxide surface damage, then oxide surfaces are protected, but residue removal efficiency decreases
Solution Approach 1:
The silane-based protective coating serves as a mediator that decouples the concentration of hydrogen fluoride from its impact on oxide surfaces. By using the protective coating as an intermediary, high concentrations of HF can be used for efficient residue removal without directly damaging the oxide surfaces, thus resolving the trade-off between protection and efficiency.
3Manufacturing precision
If dry etching is used to shape channel or gate, then high transistor density is achieved, but oxide surfaces suffer from plasma ion bombardment damage
Solution Approach 1:
The silane-based protective coating is applied as a preliminary protective measure before the dry etching process. This preliminary action protects oxide surfaces from plasma ion bombardment damage during etching, while still allowing the dry etching process to effectively shape the channel or gate structures with high precision.
Solution Approach 2:
The protective coating acts as an intermediary layer that shields oxide surfaces from the harmful effects of plasma ion bombardment during dry etching, while permitting the etching process to proceed effectively for precise feature formation.
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 effectively preserves the functionality of fin-type and complementary-type field-effect transistors by preventing damage to oxide surfaces and facilitating efficient residue removal.
Implementation Method 1
reacting the exposed oxide surfaces with a silane compound of chemical formula R—Si(R1)n(OR2)3-n
Implementation Method 2
cleaning the second intermediate structure by contacting it with a solution comprising hydrogen fluoride
Data Source
AI summary
A method for forming one or more fin-type or complementary-type field-effect transistors, comprising: i) providing a first intermediate structure comprising: a layer to be patterned, and a first hard mask having openings, ii) dry etching the layer through the openings in the hard mask, thereby forming a second intermediate structure, wherein the second intermediate structure comprises one or more exposed oxide surfaces, iii) reacting the exposed oxide surfaces with a silane compound of chemical formula R—Si(R1)n(OR2)3-n, wherein R is an organyl group, R1 is selected from hydrogen, hydroxyl, halogen, and an organyl group, R2 is selected from hydrogen and an organyl group, and n is an integer selected in the range of from 0 to 2, and then iv) cleaning the second intermediate structure having reacted oxide surfaces by contacting it with a solution comprising hydrogen fluoride.