Atomic Layer Deposition Substrate Rotation for Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional traveling wave type atomic layer deposition (ALD) systems result in wafer non-uniformity due to uneven layer formation, with the layer being thicker on portions adjacent to the gas inlet, leading to high wafer non-uniformity (WIWNU).
Innovation Solution
A method involving multiple ALD cycles performed at different relative angular positions of the substrate within the process chamber, where the substrate is rotated to evenly distribute gas supply across its periphery, ensuring uniform layer thickness by dividing the total number of cycles into steps performed at distinct angular positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If source gas and reaction gas are introduced from one side inlet in conventional traveling wave type ALD system, then the ALD process can be completed, but the layer becomes thicker on portions adjacent to the inlet causing high wafer non-uniformity
Solution Approach 1:
The patent divides the ALD process into multiple segments by performing cycles at different substrate angular positions. Instead of completing all ALD cycles with the substrate at one fixed position (conventional method), the process is segmented into multiple steps where the substrate is rotated to different angular positions (e.g., 0°, 120°, 240°) and ALD cycles are performed at each position. This segmentation of the deposition process ensures that gas supply effects are distributed uniformly across the wafer surface, reducing thickness variations and achieving better wafer non-uniformity control.
2Manufacturing precision
If substrate is kept at fixed angular position during ALD process, then process simplicity is maintained, but gas supply creates non-uniform layer thickness across the wafer
Solution Approach 1:
The patent implements periodic action by rotating the substrate to different angular positions at regular intervals during the ALD process. The substrate is rotated to specific angular positions (e.g., 0°, 120°, 240°) and ALD cycles are performed at each position in a periodic sequence. This periodic rotation and deposition cycle ensures that all regions of the wafer receive equivalent gas exposure over time, achieving uniform layer thickness while adding controlled complexity to the process sequence.
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 significantly reduces wafer non-uniformity by ensuring a more uniform thickness distribution across the wafer, as demonstrated by the comparative graphs showing improved average, standard deviation, and range of thickness distributions for hafnium oxide layers.
Implementation Method 1
performing a cycle n times while the substrate is at the first relative angular position, and performing the cycle m times while the substrate is at a second relative angular position... each cycle includes supplying source gas onto the substrate... supplying reaction gas onto the substrate
Data Source
AI summary
In a method of forming a layer, a substrate is loaded into a chamber and placed at a home position that is a first relative angular position. A process cycle is performed a number of times while the substrate is at the home position. The cycle includes directing source gas onto the substrate at a first location adjacent the periphery of the substrate, purging the chamber, directing reaction gas onto the substrate from the first location, and purging the chamber. The cycle is performed another number of times while the substrate is at another relative angular position, i.e., at a position rotated about its general center relative from the home position.