Electrostatic Chuck Heater Zoning for Wafer Temperature Uniformity
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Solution Overview
Problem
In plasma processing of semiconductor wafers, achieving temperature uniformity and controlling temperature conditions over a wide range is challenging due to the complexity of the sample stage's power-feeding structures, leading to decreased manufacturing yield and risk of temperature non-uniformity.
Innovation Solution
A plasma processing apparatus with a cylindrical sample stage featuring a basement and an electrostatic chuck equipped with a first heater and a second heater, both covered by dielectric films, divided into specific regions for individual power control, allowing for precise temperature adjustment and improved uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of heater divisions is increased to achieve local temperature control, then temperature control capability is improved, but device complexity increases
Solution Approach 1:
The heater is divided into multiple independent heating zones (first heating zone, second heating zone, third heating zone) with different heating capacities. Each zone can be controlled independently to achieve local temperature control without requiring excessive power-feeding structures. The segmentation is based on the wafer's processing requirements, with the first heating zone covering the central chip region, the second heating zone covering the intermediate scribe region, and the third heating zone covering the outer peripheral region.
Solution Approach 2:
Different regions of the heater are designed with different heating capacities to match the local temperature requirements of the wafer. The first heating zone has the highest heating capacity for the central chip region, the second heating zone has intermediate capacity for the scribe region, and the third heating zone has the lowest capacity for the outer peripheral region. This local quality differentiation allows precise temperature control in each region while simplifying the overall power-feeding structure.
2Manufacturing precision
If the number of power-feeding structures is increased to control each heater division, then temperature control precision is improved, but the number of regions without temperature control increases, leading to temperature non-uniformity
Solution Approach 1:
Multiple heating zones are merged into a single integrated heater structure with a common power-feeding system. The first, second, and third heating zones are arranged concentrically and share common electrical connections, eliminating the need for separate power-feeding structures for each zone. This merging approach maintains temperature control precision while preventing the increase in regions without temperature control, thereby preserving temperature uniformity across the wafer.
Solution Approach 2:
The single power-feeding structure serves multiple heating zones simultaneously, making it a multi-functional system. The common power-feeding structure can supply power to different combinations of heating zones depending on the processing requirements, providing universal temperature control capability across the entire wafer surface without requiring dedicated power-feeding lines for each region.
3Manufacturing precision
If detailed temperature control is implemented for miniaturized semiconductor devices, then processing accuracy is improved, but in-wafer temperature uniformity deteriorates
Solution Approach 1:
The heater system provides dynamic temperature control by independently adjusting the power supplied to each heating zone based on real-time temperature requirements. The first, second, and third heating zones can be activated or deactivated dynamically to match the specific processing needs of different wafer regions, enabling both detailed temperature control for processing accuracy and maintenance of overall temperature uniformity through coordinated control of all zones.
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
The apparatus enhances in-wafer temperature uniformity, reducing the risk of temperature deviations and thereby increasing the manufacturing yield of semiconductor wafers during plasma processing.
Implementation Method 1
the electrostatic chuck has a first heater and a second heater, each covered by a dielectric film
Implementation Method 2
a first heater and a second heater, each covered by a dielectric film
Data Source
AI summary
An electrostatic chuck 40 has a heater HT1 and a heater HT2 each covered by dielectric films 41 to 45. The heater HT2 is divided into a region HT2a having a circular shape in plan view, a region HT2b surrounding an outer periphery of the region HT2a in plan view, and a region HT2c surrounding an outer periphery of the region HT2a in plan view. The heater HT1 is divided into a plurality of regions HT1d, each having a rectangular shape in plan view. The regions HT2a to HT2c and the plurality of regions HT1d are electrically connected to a control unit C0. The control unit C0 is configured to individually control supply of power to the regions HT2a to HT2c and the plurality of regions HT1d.