Wafer Chuck Heat Flow Sensing for Precise Temperature Control
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Solution Overview
Problem
Existing wafer chucks face challenges in accurately controlling temperature due to structural limitations that restrict the number and placement of temperature sensors, particularly when dealing with high heat density devices like SoC, CPU, GPU, or APU, where localized heat generation is difficult to manage without increasing sensor density.
Innovation Solution
A wafer chuck design with distributed temperature sensors and a heat flow sensor, where thermocouples are connected in series with alternating junctions at different depths, allowing temperature measurement points to cover the entire chuck surface, enabling temperature control without increasing sensor count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of temperature sensors is increased to accurately measure localized heat generation, then temperature measurement precision is improved, but device complexity and wiring difficulty increase significantly
Solution Approach 1:
The thermocouple junctions serve dual functions: they act as heat flow sensors detecting thermal gradients while simultaneously serving as temperature measurement points. This multi-functionality allows comprehensive temperature monitoring without adding dedicated temperature sensors, resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The patent combines the heat flow sensing function and temperature measurement function into a single integrated system using thermocouple junctions. By merging these functions, the invention eliminates the need for separate temperature sensors and their associated wiring, thereby improving measurement capability while reducing device complexity.
2Measurement precision
If temperature sensors are densely distributed to cover high heat density areas, then temperature control accuracy is improved, but the structural limitations of the wafer chuck prevent adequate sensor placement
Solution Approach 1:
The patent transitions from measuring temperature at single-point locations to measuring temperature across a distributed two-dimensional plane. By arranging thermocouple junctions at multiple depth positions (first depth position and second depth position) and distributing them across the wafer chuck surface, the invention achieves comprehensive temperature coverage without requiring dense single-point sensor installation, thus overcoming structural limitations.
Solution Approach 2:
The wafer chuck temperature measurement is segmented into multiple depth layers (first depth position and second depth position) with thermocouple junctions distributed across different regions. This segmentation allows accurate capture of temperature gradients at different depths while maintaining manufacturing feasibility through systematic arrangement rather than dense random placement.
3Reliability
If more temperature sensors are installed to monitor heat generation, then temperature control reliability is improved, but the number of signal lines and wiring complexity increase significantly
Solution Approach 1:
Each thermocouple junction simultaneously performs heat flow detection and temperature measurement, eliminating the need for separate signal lines for temperature sensing. This multi-functionality maintains temperature control reliability through comprehensive monitoring while significantly reducing wiring complexity by consolidating signal paths.
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 design enables accurate temperature measurement and control of heat-generating parts on the wafer without additional sensors, maintaining consistent temperature for precise testing.
Implementation Method 1
a heat flow sensor which is disposed in the wafer chuck, and in which a plurality of thermocouples are connected in series and connecting parts between thermocouples adjacent to each other are alternately disposed at a first depth position from the holding surface and at a second depth position deeper than the first depth position
Data Source
AI summary
A wafer chuck having a holding surface for holding a wafer, the wafer chuck includes: a heating and cooling unit configured to heat or cool the wafer chuck; at least one temperature sensor disposed in the wafer chuck; and a heat flow sensor which is disposed in the wafer chuck, and in which a plurality of thermocouples are connected in series and connecting parts between thermocouples adjacent to each other are alternately disposed at a first depth position from the holding surface and at a second depth position deeper than the first depth position. The heat flow sensor has a plurality of temperature measurement points provided for the respective thermocouples, and the plurality of temperature measurement points are disposed over an entirety of the wafer chuck when the wafer chuck is seen in plan view.