Boron-Containing ALD Precursors for Bottom-Up Boron Nitride Gapfill
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Solution Overview
Problem
Existing boron nitride deposition methods face challenges such as residual halides impacting electrical performance, poor deposition at the bottom of high aspect ratio features leading to voids, and mushroom-shaped film profiles, which compromise semiconductor device integrity.
Innovation Solution
The use of mixed haloaminoborane precursors like B(NMe2)2Br in NH3 and N2 based PEALD processes results in a 'bottom-up' deposition, where the film is thicker at the bottom compared to the top and sides of high aspect ratio patterned features, addressing the void formation issue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If haloborane compounds (e.g., BCl3, BBr3) are used to deposit boron nitride films by ALD, then boron nitride films can be deposited, but residual halides remain in the films which negatively impact electrical performance
Solution Approach 1:
The patent removes the harmful halogen atoms (Cl, Br, I, F) from the boron precursor structure entirely, replacing them with non-halogenating groups (NR2)2 to eliminate residual halide contamination while maintaining the ability to deposit boron nitride films with high electrical performance
Solution Approach 2:
The patent employs aminoborane compounds that decompose completely during the deposition process, leaving no harmful residues. The precursor serves its purpose of delivering boron and nitrogen atoms, then fully decomposes to leave only the desired boron nitride film without persistent halide contaminants
2Manufacturing precision
If conventional deposition methods are used, then material deposits on the top region or walls of trenches, but deposition at the bottom of high aspect ratio features is poor leading to voids
Solution Approach 1:
The patent inverts the conventional deposition pattern by achieving bottom-up filling instead of top-down deposition. The (NR2)2B precursor enables the reaction to proceed from the bottom of high aspect ratio features upward, ensuring complete filling without voids while maintaining uniform film thickness throughout the structure
Solution Approach 2:
The patent creates locally enhanced deposition at the bottom of high aspect ratio features through the unique reaction chemistry of (NR2)2B precursors, which favor bottom-up growth. This localized quality enhancement ensures complete gapfill in difficult-to-reach areas while maintaining overall film uniformity
3Manufacturing precision
If conventional ALD processes are used, then boron nitride films can be deposited, but mushroom-shaped film profiles are formed with thicker material on top and thinner material at the bottom
Solution Approach 1:
The patent inverts the conventional mushroom-shaped profile by achieving uniform thickness throughout the feature depth. The (NR2)2B precursor chemistry enables reaction propagation from bottom to top, eliminating the thickness gradient that creates mushroom shapes and producing uniform cylindrical or rectangular film profiles instead
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 enables effective gapfill in high aspect ratio features, ensuring complete filling without voids and enhancing the structural integrity of semiconductor devices.
Implementation Method 1
forming the boron-containing film on the surface in a deposition process selected from a chemical vapor deposition and atomic layer deposition process
Implementation Method 2
forming the boron-containing film on the surface in a deposition process selected from a chemical vapor deposition and atomic layer deposition process
Implementation Method 3
providing a nitrogen-containing source to deposit the film onto the at least one surface
Data Source
AI summary
A boron-containing precursor having the structure of Formula I:B(NR1R2)nX3-n (I),wherein R1 is selected from a linear C1 to C10 alkyl group, a branched C3 to C10 alkyl group, a linear or branched C3 to C10 alkenyl group, a linear or branched C3 to C10 alkynyl group, a C1 to C6 dialkylamino group, an electron withdrawing group, and a C4 to C10 aryl group; R2 is selected from hydrogen, a linear C1 to C10 alkyl group, a branched C3 to C10 alkyl group, a linear or branched C3 to C6 alkenyl group, a linear or branched C3 to C6 alkynyl group, a C1 to C6 dialkylamino group, a C6 to C10 aryl group, a linear or branched C1 to C6 fluorinated alkyl group, an electron withdrawing group, and a C4 to C10 aryl group; X is Cl, Br, I, or F; and n=1 or 2, wherein R1 and R2 are optionally linked together to form a ring selected from a substituted or unsubstituted aromatic ring or a substituted or unsubstituted aliphatic ring, and wherein R1 and R2 may be the same moiety or different moieties. Deposition methods are also disclosed.