Spatial Wafer Processing Temperature Uniformity
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Solution Overview
Problem
Current atomic layer deposition (ALD) processes face challenges with incompatible chemistries leading to chemical vapor deposition, non-uniform temperature distribution causing defects, and insufficient energy delivery to vertical wafer surfaces, resulting in film non-uniformity and plasma damage.
Innovation Solution
A processing chamber with multiple spatially separated processing stations, each with controlled temperature and emissivity, and a substrate support assembly that moves wafers between these stations to maintain matching thermal environments and minimize azimuthal variation, ensuring uniform plasma exposure and energy distribution across the wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a wafer is moved into different thermal environments in spatial ALD deposition tools, then processing flexibility and throughput are improved, but temperature non-uniformity on the wafer increases
Solution Approach 1:
The patent applies parameter changes by adjusting the emissivity and temperature of different showerheads to compensate for the thermal environment changes when wafers move between processing stations. Specifically, the plasma showerhead is configured with different emissivity and temperature parameters compared to the deposition showerhead, ensuring that the net thermal energy received by the wafer remains consistent across different processing environments, thereby maintaining temperature uniformity while enabling high throughput spatial ALD processing
Solution Approach 2:
The patent implements feedback control through temperature sensors positioned at multiple locations on the wafer support surface that continuously monitor wafer temperature. This temperature data is fed back to a control system that adjusts the heating elements and showerhead parameters in real-time to compensate for thermal variations, ensuring uniform wafer temperature despite the wafer moving between different thermal environments during spatial ALD cycles
2Temperature
If plasma is used to provide additional energy for film deposition below thermal process temperatures, then film quality at lower temperatures is improved, but non-uniform energy distribution and plasma damage occur
Solution Approach 1:
The patent applies local quality by creating a non-uniform plasma field with higher power density at the wafer center and lower power density at the edges. This is achieved through selective electrode positioning and power distribution in the plasma showerhead, which compensates for the natural tendency of plasma to be more intense at edges. The localized adjustment of plasma parameters ensures uniform energy delivery across the entire wafer surface, enabling high-quality film deposition at reduced temperatures without edge-enhancement effects or plasma damage
Solution Approach 2:
The patent implements preliminary anti-action by pre-configuring the plasma showerhead with specific electrode arrangements and power distribution patterns that anticipate and counteract potential plasma-induced non-uniformities and damage. The system预先 establishes a controlled plasma environment with optimized parameters that prevent excessive ion bombardment and heating, thereby protecting the wafer and film from plasma damage while still providing the necessary energy for low-temperature deposition
3Loss of time
If incompatible chemistries are mixed in the gas phase, then processing time is reduced, but CVD process occurs instead of ALD resulting in less thickness control and gas phase particles
Solution Approach 1:
The patent transitions from time-domain sequential processing to spatial parallel processing by implementing multiple deposition stations arranged in a circular configuration with a rotating wafer support. This spatial arrangement allows different precursor and reactant gases to be introduced simultaneously at different spatial locations around the wafer, eliminating the need for lengthy purge cycles between chemistry switches. The spatial separation of incompatible chemistries in the gas phase, combined with rapid wafer rotation through the different gas zones, maintains precise ALD thickness control while dramatically reducing processing time
Solution Approach 2:
The patent applies dynamics through the continuous rotation of the wafer support assembly, which dynamically moves the wafer through different gas environments in a controlled sequence. This dynamic motion allows the system to rapidly transition between different chemical reactions without requiring static purge cycles, as the wafer continuously moves from one gas phase environment to the next, preventing gas phase mixing while maintaining precise temporal control over each deposition step
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 enhances film uniformity, reduces temperature non-uniformity, and improves plasma exposure, leading to higher quality films with better thickness control and refractive index consistency, while minimizing plasma damage.
Implementation Method 1
a first gas injector having a first face, a first emissivity and a first temperature; a second gas injector having a second face, a second emissivity and a second temperature
Data Source
AI summary
Apparatus and methods to process one or more wafers are described. A processing chamber comprises a first processing station comprising a first gas injector having a first face, a first emissivity and a first temperature, a second processing station comprising a second gas injector having a second face, a second emissivity and a second temperature, and a substrate support assembly comprising a plurality of substantially coplanar support surfaces, the substrate support assembly configured to move the support surfaces between the first processing station and the second processing station. When a wafer is on the support surfaces, a temperature skew of less than about 0.5° C. is developed upon moving the wafer between the stations in about 0.5 seconds.