Selective Metal Film Deposition on SiN Over SiO2 Surfaces
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Solution Overview
Problem
The semiconductor industry faces challenges in selectively depositing metal films on silicon nitride surfaces while preventing deposition on silicon dioxide surfaces, as current technologies are not effective in blocking deposition precursors on similar surfaces.
Innovation Solution
The method involves using a blocking precursor, such as trimethylsilylpyrrolidine, to selectively block silicon dioxide surfaces, allowing for the deposition of metal films on silicon nitride surfaces through atomic layer deposition by using specific metal precursors that react with the nitride surfaces but not the oxide surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional surface blocking methods are used, then deposition selectivity can be achieved on surfaces with drastically different surface energies, but deposition selectivity fails when surfaces are similar (SiO2 versus SiN)
Solution Approach 1:
The patent changes the chemical parameters of the blocking agent by using organosilane compounds with specific functional groups that selectively react with silicon nitride surfaces. The blocking agent formula R3Si-X contains reactive handles (X = halide, azide, amino, hydrazide, cyanide, or isocyanate) that create chemical selectivity between similar surfaces, enabling differentiation between SiO2 and SiN surfaces through chemical reactivity rather than physical surface energy differences.
2Ease of manufacture
If selective deposition is implemented to remove lithographic steps, then manufacturing cost can be reduced, but process complexity increases due to surface treatment requirements
Solution Approach 1:
The patent applies preliminary surface blocking treatment before the deposition process. The blocking precursor is exposed to the substrate first to form a protective layer on SiO2 surfaces, then the metal precursor is deposited. This preliminary action simplifies the overall process by enabling direct selective deposition without requiring complex real-time control or multiple sequential steps, thereby reducing both cost and complexity.
3Reliability
If current blocking technologies are used, then some surfaces can be protected, but deposition precursors are not effectively blocked on similar surfaces like SiO2
Solution Approach 1:
The patent introduces an intermediary blocking agent (organosilane compound) that mediates between the deposition precursor and the substrate surface. The blocking agent R3Si-X acts as a chemical intermediary that selectively binds to SiO2 surfaces through its reactive handle X, creating a steric and chemical barrier that prevents metal precursor adsorption. This intermediary approach achieves reliable blocking on surfaces that are chemically similar to the target deposition surface.
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 selective deposition of metal films, such as titanium nitride and hafnium oxide, with minimal or no deposition on silicon oxide surfaces, simplifying the integration process and reducing manufacturing costs by eliminating costly lithographic steps.
Implementation Method 1
exposing a substrate with a first surface comprising SiO2 and a second surface comprising SixNy to a blocking precursor to form a blocked first surface
Implementation Method 2
The substrate is exposed to a metal precursor. The metal precursor comprises a compound of the formula M(NR′2)a where each R′ is independently C1-C4 alkyl and is greater than or equal to one
Implementation Method 3
The substrate is exposed to a reagent to react with the metal precursor to form a metal film on the second layer
Data Source
AI summary
Methods and precursors for selectively depositing a metal film on a silicon nitride surface relative to a silicon oxide surface are described. The substrate comprising both surfaces is exposed to a blocking compound to selectively block the silicon oxide surface. A metal film is then selectively deposited on the silicon nitride surface.