Multi-Zone Ceramic Heater Layout for Uniform Wafer Heating
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Solution Overview
Problem
Ceramic heaters in semiconductor manufacturing face issues with temperature control due to conductive connections, leading to cool or hot spots and potential damage from thermal stress, especially when power ratios change or thermal expansion differences occur.
Innovation Solution
A multi-zone heater design featuring a disc-shaped ceramic substrate with a coil-shaped central zone heater and mesh-shaped or coil-shaped outer circumferential zone heaters, using meandering elemental wire connections that adjust heat generation based on environmental changes to prevent temperature imbalances and absorb thermal expansion differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a coil is used as the conductive connection portion, then the heat generation amount is increased, but the temperature control for the central portion is influenced and cool spots or hot spots are generated
Solution Approach 1:
The patent introduces an intermediary substance (thermal conductive paste or metal plate) between the coil and the ceramic substrate to mediate the heat transfer. This intermediary allows the coil to generate heat while distributing it more evenly through the substrate, preventing localized temperature extremes and cool spots in the central portion.
2Temperature
If an elemental wire is used as the conductive connection portion, then the heat generation amount is reduced, but thermal expansion differences cause damage to the ceramic substrate
Solution Approach 1:
The patent changes the physical parameters of the connection portion by giving the elemental wire a meandering shape instead of a straight configuration. This shape change allows the wire to accommodate thermal expansion differences between the ceramic substrate and the wire material, absorbing stress and preventing substrate damage while maintaining low heat generation.
3Adaptability or versatility
If the power ratio between central zone heater and outer circumferential zone heater is varied, then temperature control flexibility is improved, but cool spots or hot spots are generated around the conductive connection portion
Solution Approach 1:
The patent applies local quality by creating a meandering connection portion specifically at the conductive connection area, while keeping other parts of the heater structure straightforward. This localized meandering design addresses temperature uniformity issues at the connection portion without affecting the overall temperature control flexibility of the multi-zone heater system.
4Reliability
If the conductive connection portion extends through the central portion, then electrical connection is achieved, but temperature around the connection portion is reduced
Solution Approach 1:
The patent uses curvature by designing the conductive connection portion with a meandering shape instead of a straight line. This curved path increases the length of the connection portion, allowing it to better conduct electricity while also distributing heat more evenly along its length, preventing temperature reduction at specific locations.
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 design effectively prevents cool or hot spots and reduces thermal stress on the ceramic substrate, ensuring precise temperature control and preventing damage by adjusting heat generation dynamically with environmental changes.
Implementation Method 1
the heat generation amount can be increased by forming the first and second elemental wire portions in a curved shape at a position where a cool spot is likely to be generated due to changes in the use environment
Implementation Method 2
when the multi-zone heater is used in an environment in which a heat cycle is repeatedly generated, the difference in thermal expansion occurs between the ceramic substrate and the heaters embedded in the ceramic substrate
Data Source
AI summary
A multi-zone heater includes an outer circumferential zone heater and first and second elemental wire portions. The outer circumferential zone heater is a coil that is provided in an outer circumferential zone of a ceramic substrate in the same plane as a plane in which a central zone heater is provided and that is routed throughout the outer circumferential zone in a unicursal manner from one end portion to the other end portion in the outer circumferential portion. The first elemental wire portion extends from a first terminal, passes through a central portion, is connected to the one end portion of the outer circumferential zone heater, and has a meandering shape in plan view. The second elemental wire portion extends from a second terminal, passes through the central portion, is connected to the other end portion of the outer circumferential zone heater, and has a meandering shape in plan view.