Multi-Zone Pedestal Heater Layout Without Vias or Cold Spots
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Solution Overview
Problem
Conventional wafer support pedestals in semiconductor processing have limited heating zones and temperature sensing capabilities due to the presence of electric terminations, leading to inefficient heat distribution and monitoring, which restricts the number of independently controlled heating zones and precise temperature monitoring.
Innovation Solution
A multi-zone support pedestal with resistive heating elements on different planes of the substrate, connected via a thermal array system that eliminates the need for routing layers and interconnects, allowing for closed-loop control of multiple heating zones using resistive heating elements as both heaters and temperature sensors, connected through a customizable feedback control system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electric terminations are disposed in the central region of the substrate, then electrical connections are established, but the central region size is reduced creating cold spots
Solution Approach 1:
The patent transitions from planar heating elements to three-dimensional vertically stacked heating elements. Multiple heating zones are arranged in different vertical layers, allowing electric terminations to be positioned in the central region without creating cold spots on the wafer surface, as the heating occurs from multiple elevated positions rather than a single plane
Solution Approach 2:
The heating system is divided into multiple independent heating zones arranged in different vertical planes. Each heating zone can be independently controlled and positioned at different heights, allowing the central region to accommodate terminations while maintaining effective heating coverage across the wafer surface
2Temperature
If the central region size is reduced to minimize cold spots, then temperature uniformity improves, but the number of electric terminations is limited
Solution Approach 1:
By stacking heating zones in multiple vertical planes, the system accommodates multiple electric terminations in the central region without compromising temperature uniformity. The vertical arrangement allows terminations at different heights to connect to different heating zones while maintaining uniform heat distribution across the wafer
Solution Approach 2:
The central region is designed to serve dual purposes: accommodating electric terminations for multiple heating zones while simultaneously maintaining temperature uniformity through the vertical stacking arrangement. The same central region area supports both electrical connections and thermal management functions
3Device complexity
If the number of heating zones is limited to one or two, then device complexity is reduced, but temperature control precision deteriorates
Solution Approach 1:
The heating system is segmented into multiple independently controllable heating zones arranged in different vertical planes. Each zone can be individually adjusted to compensate for local temperature variations, enabling precise temperature control across different wafer regions without requiring complex integrated circuits
Solution Approach 2:
Temperature sensors are integrated into the pedestal structure to provide real-time temperature feedback from multiple locations. This feedback is used to dynamically adjust the power supplied to each heating zone, enabling precise closed-loop temperature control that compensates for thermal gradients and environmental variations
4Measurement precision
If conventional heating systems are used with separate sensing devices, then temperature monitoring is achieved, but device complexity increases
Solution Approach 1:
Temperature sensing capabilities are merged directly into the pedestal structure itself rather than using separate external sensing devices. The pedestal incorporates integrated temperature sensors that provide real-time temperature monitoring, eliminating the need for additional separate sensing components and their associated wiring and control circuits
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 configuration enhances the performance and reliability of the pedestal by enabling independent control of multiple heating zones, reducing manufacturing complexity, and eliminating the need for separate sensing devices, while improving temperature uniformity and extending the lifespan of the pedestal.
Implementation Method 1
The wafer support portion may include a resistive heating element for generating heat
Data Source
AI summary
A support pedestal includes a substrate, a plurality of resistive heating elements disposed on the substrate and defining a plurality of heating zones, and electric terminals disposed at a central region of the substrate. At least one of the electric terminals is connected to at least two of the plurality of resistive heating elements.