Spatial Deposition Chamber Layout for Uniform Plasma ALD
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Solution Overview
Problem
Current atomic layer deposition (ALD) processes face issues with incompatible chemistries leading to chemical vapor deposition (CVD), non-uniform plasma exposure causing defects, and challenges in optimizing plasma environments for vertical side wall film properties, resulting in non-uniform film thickness and plasma damage.
Innovation Solution
A processing chamber with spatially separated isolated processing stations, each with independent temperature and gas flow control, and a substrate support assembly that rotates wafers through multiple stations to optimize plasma exposure and uniform film deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional time-domain ALD process is used with a single reactive gas flowed into the processing chamber at a time, then the chemistries are kept separate and CVD is avoided, but the purge/pump out time is long resulting in low throughput
Solution Approach 1:
The processing chamber is divided into multiple spatially separated isolated processing stations, each capable of holding different chemistries independently. This segmentation allows simultaneous presence of multiple chemistries in different spatial zones without mixing, eliminating the need for long purge times while maintaining chemistry separation integrity.
Solution Approach 2:
The patent transitions from temporal separation (time-domain) to spatial separation. Instead of sequentially introducing gases and purging between steps, multiple reactive gases are introduced simultaneously into different spatial zones of the chamber, with the substrate moving through these zones to receive alternating exposures.
2Use of energy by moving object
If a capacitively coupled plasma (CCP) is used to provide ion energy, then plasma generation is achieved, but the ion energies are very high causing poor performance on vertical side wall surfaces
Solution Approach 1:
Different processing stations are configured with different plasma characteristics. One station provides high ion energy for horizontal surfaces while another station provides lower ion energy with wider angular distribution optimized for vertical side wall surfaces. The substrate moves between these stations to receive appropriate plasma treatment for each surface orientation.
Solution Approach 2:
The substrate support rotates the substrate to dynamically present different surfaces (horizontal vs. vertical) to different processing stations at different times. This dynamic positioning allows optimization of plasma parameters for each surface orientation without requiring multiple static chambers.
3Productivity
If the substrate support assembly rotates at constant speed through multiple processing stations, then throughput is maintained, but non-uniform plasma exposure occurs causing leading and trailing edge differences on the wafer
Solution Approach 1:
The processing stations are arranged asymmetrically around the substrate support, with different numbers of stations of each type positioned at specific locations. This asymmetric arrangement, combined with bidirectional rotation, helps balance the cumulative exposure time and plasma conditions across different wafer regions, reducing leading/trailing edge non-uniformities.
Solution Approach 2:
The substrate support performs periodic bidirectional rotation cycles, alternating direction after a predetermined number of rotations. This periodic reversal of rotation direction compensates for cumulative non-uniformities that would develop with unidirectional rotation, distributing plasma exposure more evenly across the wafer surface over time.
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
Achieves higher throughput and uniform film thickness across the wafer surface by optimizing plasma exposure and minimizing plasma damage, enabling efficient deposition of high-quality films at lower temperatures.
Implementation Method 1
spatially separated isolated processing stations... optimize plasma exposure and uniform film deposition
Implementation Method 2
Current atomic layer deposition (ALD) processes... chemical vapor deposition (CVD) process
Data Source
AI summary
Apparatus and methods to process one or more wafers are described. A spatial deposition tool comprises a plurality of substrate support surfaces on a substrate support assembly and a plurality of spatially separated and isolated processing stations. The spatially separated isolated processing stations have independently controlled temperature, processing gas types, and gas flows. In some embodiments, the processing gases on one or multiple processing stations are activated using plasma sources. The operation of the spatial tool comprises rotating the substrate assembly in a first direction, and rotating the substrate assembly in a second direction, and repeating the rotations in the first direction and the second direction until a predetermined thickness is deposited on the substrate surface(s).