FinFET Fabrication Using Dilute HF Cleaning Solutions
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Solution Overview
Problem
Conventional cleaning processes in semiconductor manufacturing, particularly for FinFET fabrication, face challenges in achieving effective residue removal without excessive material loss or surface uniformity issues, leading to decreased product yields and performance.
Innovation Solution
The method involves using specific cleaning solutions, such as dilute hydrogen fluoride and ozonated deionized water, and ammonium hydroxide with ozonated deionized water, to perform controlled cleaning processes that minimize material loss and enhance surface uniformity, allowing for precursor oxide formation and efficient removal of residues before gate and source/drain structure formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cleaning solutions are used to remove particles and residues, then cleaning effectiveness is improved, but material loss of substrate and formed materials increases
Solution Approach 1:
The patent changes the chemical composition parameters of the cleaning solution by using diluted hydrogen fluoride (300:1 to 2000:1 dilution ratio) combined with ozonated deionized water or hydrogen peroxide, creating a selective cleaning environment that removes residues while preserving substrate and formed materials
Solution Approach 2:
The patent introduces an intermediary precursor oxide layer that forms during the cleaning process, which acts as a protective barrier between the cleaning solution and the substrate/formed materials, enabling effective residue removal while minimizing material loss
2Productivity
If cleaning solutions with sufficient etching ratio are used to improve cleaning efficiency, then residue removal is enhanced, but surface uniformity deteriorates
Solution Approach 1:
The patent optimizes the etching ratio parameter by using highly diluted hydrogen fluoride (300:1 to 2000:1), which provides sufficient cleaning efficiency while maintaining surface uniformity through controlled, gentle etching action
Solution Approach 2:
The cleaning process is applied periodically at specific stages (after recess formation and before gate oxide formation) with controlled duration (10-80 seconds), ensuring residues are removed without excessive etching that would compromise surface uniformity
3Reliability
If multiple cleaning steps are added to improve cleaning effectiveness, then residue removal is enhanced, but process complexity increases
Solution Approach 1:
The cleaning solution performs multiple functions simultaneously: removing organic residues, removing inorganic residues, forming precursor oxide, and protecting formed materials, thereby consolidating what would traditionally require multiple separate cleaning steps into a single effective process
Solution Approach 2:
The patent merges the cleaning function with the precursor oxide formation function into a single integrated process step, eliminating the need for separate cleaning and oxide formation steps, thus reducing overall process complexity
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 removes particles and residues while limiting material loss, improving surface uniformity and product yields, and reducing the need for additional cleaning steps, thereby enhancing the fabrication process efficiency and cost-effectiveness.
Implementation Method 1
The cleaning process is performed on the fin structures and the dielectric layer using a cleaning solution selected from one of a first solution and a second solution, wherein the first solution consists of dilute hydrogen fluoride and hydrogen peroxide and the second solution consists of dilute hydrogen fluoride and ozonated deionized water
Implementation Method 2
the first solution consists of dilute hydrogen fluoride and hydrogen peroxide and the second solution consists of dilute hydrogen fluoride and ozonated deionized water
Data Source
AI summary
The invention provides a fabricating method of a FinFET, comprising: providing a substrate having fin structures; depositing an dielectric layer on the substrate filling between the fin structures; forming recesses to reveal a portion of the fin structure by removing a portion of the dielectric layer; performing a cleaning process on using a cleaning solution selected from one of a first solution, consisting of dHF and H2O2, and a second solution, consisting of dHF and DIO3; forming a gate structure across on the fin structures; and forming a source/drain structure on the substrate at two lateral sides of the gate structure. The present invention also provides a fabricating method of a FinFET having an improved cleaning step using a cleaning solution having one of a third solution, consisting of dHF and DIO3, and a fourth solution, consisting of NH4OH and DIO3 before formation of the source/drain structure.