Symmetrical Multi-Zone Ceramic Heater for Wafer Thermal Uniformity
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Solution Overview
Problem
Multi-zone ceramic heaters used in semiconductor manufacturing often suffer from poor thermal uniformity due to differences in heating element curvature and the presence of lift pin holes, leading to temperature variations at singular points.
Innovation Solution
The multi-zone heater is configured with a disc-shaped ceramic substrate, inner and outer zone heaters, and leads arranged symmetrically with respect to a common axis of symmetry, ensuring that the lift pin holes, inner zone heater, and outer zone heater are symmetrically positioned.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If heating elements are arranged in arcs concentric with the ceramic substrate to heat inner and outer zones independently, then independent temperature control of zones is achieved, but the heating element must be bent around leads and lift pin holes creating curvature radius singular points that cause poor thermal uniformity
Solution Approach 1:
The patent intentionally introduces asymmetric dummy heating elements at the curvature radius singular points where the heating element bends around leads and lift pin holes. These dummy elements compensate for the heat generation deficiency at these specific locations, balancing the thermal output across the entire heating surface and eliminating the poor thermal uniformity caused by the asymmetric bending geometry.
2Ease of manufacture
If leads are routed across the inner zone to connect outer zone heating elements to terminals, then electrical connection is achieved, but the heating element must bend around the lead creating a curvature radius singular point that causes temperature variation
Solution Approach 1:
The patent introduces dummy heating elements as intermediary components at the locations where the heating element bends around the leads. These dummy elements act as thermal mediators that compensate for the heat generation imbalance caused by the bending, allowing the leads to be routed across the inner zone while maintaining overall thermal uniformity.
3Ease of operation
If lift pin holes are provided in the ceramic substrate to support and lift the wafer, then wafer lifting function is achieved, but the heating element must circumvent these holes creating curvature radius singular points that cause poor thermal uniformity
Solution Approach 1:
The patent applies local quality by adding dummy heating elements specifically at the curvature radius singular points where the heating element circumvents the lift pin holes. This localized compensation ensures that the thermal uniformity is maintained at these specific critical locations without affecting the overall heating element design or wafer lifting functionality.
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 significantly improves thermal uniformity at the wafer mounting surface during heating, reducing temperature variations and enhancing the productivity of semiconductor manufacturing processes.
Implementation Method 1
a heating element (coil) to heat a central portion (an inner zone) of a disc-shaped ceramic substrate and a heating element (coil) to heat an outer peripheral portion (outer zone)
Data Source
AI summary
A multi-zone heater capable of heating a wafer mounted on a disc-shaped ceramic substrate includes: a plurality of lift pin holes which are provided in the substrate; an inner zone heater embedded in an inner zone of the ceramic substrate; an outer zone heater embedded in an outer zone outside the inner zone; first and second feed terminals to which opposite ends of the inner zone heater are connected; first and second leads to which opposite ends of the outer zone heater are connected; and third and fourth feed terminals to which the first and second leads are respectively connected, the plurality of lift pin holes, the inner zone heater, and the outer zone heater are arranged to be symmetric with respect to a common axis of symmetry, and the first and second leads are arranged along the axis of symmetry to be symmetric to each other.