Multi-zone electrostatic chuck for semiconductor wafer temperature control
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Solution Overview
Problem
Processing larger semiconductor wafers introduces mechanical challenges, such as achieving and maintaining uniform temperature, which leads to hot spots and variations in processing steps, affecting chip uniformity and performance.
Innovation Solution
An electrostatic chuck with multiple temperature zones and independent coolant sources is used to maintain uniform wafer temperature during ion implantation, employing different coolants in various zones to control temperature and prevent radial variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If discrete heating or cooling is applied at specific locations on the wafer, then localized temperature control is achieved, but hot spots or cold spots occur on the wafer
Solution Approach 1:
The electrostatic chuck is divided into multiple independently controllable temperature zones (e.g., first, second, third, and fourth zones) arranged in a grid pattern across the wafer surface. Each zone has its own heating element and temperature control, allowing localized temperature adjustment without creating hot or cold spots that would affect overall wafer uniformity
Solution Approach 2:
Different temperature zones can be set to different temperature profiles based on local process requirements. For example, edge zones can be heated differently from center zones, or specific regions can be cooled more aggressively based on local hot spot formation, achieving optimal temperature distribution across the entire wafer surface
2Manufacturing precision
If a single coolant source is used for the entire electrostatic chuck, then system complexity is reduced, but temperature uniformity across the wafer cannot be maintained
Solution Approach 1:
The coolant delivery system is segmented into multiple independent coolant sources (first, second, third, and fourth coolant sources), each connected to specific temperature zones on the electrostatic chuck. This allows different coolant flows and temperatures to be applied to different regions, maintaining wafer temperature uniformity across the large wafer surface
Solution Approach 2:
Each coolant source can be independently controlled to provide appropriate cooling to specific zones based on local temperature requirements. For example, zones experiencing higher temperatures can receive increased coolant flow or lower temperature coolant, while cooler zones receive less cooling, achieving overall temperature uniformity
3Productivity
If larger diameter wafers (450 mm) are used to increase productivity, then the number of dies per wafer increases, but maintaining uniform processing conditions becomes more difficult
Solution Approach 1:
The electrostatic chuck and temperature control system are designed with multiple zones (at least four zones) that can independently control temperature across different regions of the large 450 mm wafer. This segmentation allows each zone to compensate for local thermal variations that occur with larger wafer diameters, maintaining uniform processing conditions across the entire wafer surface
Solution Approach 2:
Different regions of the large wafer can have different temperature profiles applied to them based on local requirements. Edge regions, center regions, and intermediate regions can all be independently controlled to achieve optimal temperature distribution, ensuring uniform processing conditions across the entire 450 mm wafer despite its large size
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 solution ensures improved critical dimension uniformity and reduced substrate damage, enhancing within-wafer junction leakage performance and threshold voltage uniformity.
Implementation Method 1
An electrostatic chuck is provided within the process chamber. The electrostatic chuck is configured to support a semiconductor wafer.
Implementation Method 2
Each temperature zone includes at least one fluid conduit within or adjacent to the electrostatic chuck. At least two coolant sources are provided. Each coolant source is fluidly coupled to a respective one of the fluid conduits and configured to supply a respectively different coolant to a respective one of the plurality of temperature zones
Data Source
AI summary
An apparatus and a method for controlling critical dimension (CD) of a circuit is provided. An apparatus includes a controller for receiving CD measurements at respective locations in a circuit pattern in an etched film on a first substrate and a single wafer chamber for forming a second film of the film material on a second substrate. The single wafer chamber is responsive to a signal from the controller to locally adjust a thickness of the second film based on the measured CD's. A method provides for etching a circuit pattern of a film on a first substrate, measuring CD's of the circuit pattern, adjusting a single wafer chamber to form a second film on a second semiconductor substrate based on the measured CD. The second film thickness is locally adjusted based on the measured CD's.