Atomic Layer Deposition Gas Sequencing for HF Exhaust
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Solution Overview
Problem
In atomic layer deposition (ALD) processes, accurately forming films in narrow spaces of semiconductor devices is challenging due to the difficulty in efficiently exhausting byproducts like HF, which affects the characteristics and reliability of the semiconductor devices.
Innovation Solution
A film forming method involving alternating sequences of supplying film forming gas, purge gas, reduction gas, and purge gas, with controlled repetition of these sequences to efficiently exhaust byproducts while minimizing process time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ALD processes are used to form films in narrow spaces, then film formation can be achieved, but byproducts like HF cannot be efficiently exhausted, affecting device characteristics and reliability
Solution Approach 1:
The patent segments the film formation process into multiple cycles, each consisting of: (1) supplying film forming gas for a first period to form a film, (2) supplying first purge gas for a second period to exhaust byproducts, (3) supplying reduction gas for a third period to reduce residual film forming gas and byproducts, and (4) supplying second purge gas for a fourth period to exhaust the reduction byproducts. This segmented multi-stage approach ensures thorough removal of harmful byproducts like HF from narrow spaces while maintaining film formation quality and device reliability
Solution Approach 2:
The patent implements continuous byproduct exhaustion throughout the film formation process by alternating film formation with purge and reduction steps. Rather than forming the complete film first and then removing byproducts, the system continuously performs short film formation cycles interspersed with purge and reduction steps, ensuring byproducts are removed as they are generated, preventing accumulation that would harm device reliability
2Object-generated harmful factors
If multiple purge steps are added to exhaust byproducts, then byproduct removal improves, but process time increases
Solution Approach 1:
The patent merges the purge function and reduction function into a single integrated step where reduction gas serves dual purposes: it reduces residual film forming gas on the substrate surface and simultaneously acts as a purge gas to exhaust byproducts like HF. This merging of functions eliminates the need for separate purge steps, achieving thorough byproduct removal while minimizing process time
Solution Approach 2:
The patent optimizes the timing and duration parameters of each gas supply step to achieve efficient byproduct removal within minimal time. By carefully controlling the periods for film formation, purging, and reduction, the process achieves complete byproduct exhaustion without excessive cycle time, balancing reliability improvement with productivity maintenance
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 method allows for accurate film formation in narrow spaces, improving the characteristics and reliability of semiconductor devices by effectively removing byproducts like HF, thus enhancing the film forming process efficiency.
Implementation Method 1
supplying a film forming gas into a film forming chamber
Implementation Method 2
supplying a reduction gas into the film forming chamber
Data Source
AI summary
According to one embodiment, a film forming method includes alternately performing a first process including at least two times of a first sequence and a second process including at least one time of a second sequence. The first sequence includes supplying a film forming gas into a film forming chamber, supplying a first purge gas into the film forming chamber, supplying a first reduction gas into the film forming chamber, and supplying a second purge gas into the film forming chamber, in order, and the second sequence includes supplying a second reduction gas into the film forming chamber, and supplying a third purge gas into the film forming chamber, in order.