ALD Deposition Selectivity via Intermittent Purge Cycles
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Solution Overview
Problem
The challenge in FinFET manufacturing lies in achieving selective deposition on complex surfaces, where precursor nucleation on inhibitor-coated areas limits deposition selectivity, leading to unwanted material buildup and increased processing complexity.
Innovation Solution
Implementing an intermittent purge process during Atomic Layer Deposition (ALD) to enhance deposition selectivity by removing unadsorbed precursor molecules, thereby preventing nucleation on inhibitor-coated surfaces and reducing material deposition in unwanted regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional ALD deposition is performed without intermittent purges, then deposition rate is maintained, but precursor nucleation on inhibitor-coated surfaces occurs leading to reduced deposition selectivity and unwanted material buildup
Solution Approach 1:
The patent implements intermittent purge cycles during ALD deposition, where purges are performed periodically between deposition cycles. This periodic action removes unadsorbed precursor molecules from inhibitor-coated surfaces at specific intervals, preventing nucleation while maintaining overall deposition progress on target surfaces.
Solution Approach 2:
The purge process acts as an intermediary step between deposition cycles, temporarily removing precursor molecules that would otherwise nucleate on inhibitor surfaces. This intermediary action allows the deposition process to proceed with high selectivity by mediating between the need for continuous deposition and the need to prevent unwanted nucleation.
2Length of stationary object
If thicker films are deposited to achieve desired thickness, then film thickness requirement is met, but premature nucleation on inhibitor surfaces occurs limiting the achievable thickness
Solution Approach 1:
The patent performs preliminary purges before initiating deposition cycles and at intervals during deposition. This preliminary and periodic removal of precursor molecules prevents premature nucleation on inhibitor surfaces, allowing the deposition process to continue for longer durations and achieve thicker films without compromising selectivity.
3Manufacturing precision
If additional processing steps are added to remove unwanted material buildup, then deposition selectivity is improved, but processing complexity and time increase
Solution Approach 1:
The patent converts the potentially harmful effect of precursor accumulation on inhibitor surfaces into a beneficial process by using the purge steps to actively remove precursors. This transforms what would be a source of contamination and selectivity loss into a controlled mechanism that enhances deposition selectivity without requiring additional post-processing removal steps.
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 improves deposition selectivity, allowing for thicker film deposition without premature buildup, reduces the need for additional processing steps, and minimizes contamination, thus simplifying the FinFET manufacturing process.
Implementation Method 1
performing a purge process that removes unadsorbed precursor from the substrate
Implementation Method 2
each deposition cycle includes adsorbing a first precursor over the substrate; adsorbing a second precursor over the substrate
Implementation Method 3
depositing a film on a second surface of the semiconductor device by performing a first set of deposition cycles
Data Source
AI summary
A method includes depositing an inhibitor layer on a first surface, depositing a film on a second surface by performing a first set of deposition cycles. Each deposition cycle includes adsorbing a first precursor over the second surface, performing a first purge process, adsorbing a second precursor over the second surface, and performing a second purge process. The method also includes performing a third purge process that is different from the first purge process or the second purge process.