Wafer Temperature Control Using Median Offset Segmentation
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Solution Overview
Problem
Existing temperature control techniques for semiconductor wafers either fail to effectively reduce non-uniformity in temperature distribution or inadvertently increase it, limiting the precision of semiconductor device manufacturing.
Innovation Solution
A temperature control apparatus comprising a first temperature measurement unit for the entire surface, a second temperature measurement unit for divided areas, a median value calculator, an offset calculator, and a temperature control unit that adjusts temperatures to achieve uniform median values across each area, ensuring precise temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the protruding amount of supporting pins is adjusted to control temperature distribution, then non-uniform temperature distribution is suppressed, but the effect is very limiting
Solution Approach 1:
The heating stage surface is divided into multiple divided areas, with independent heating elements in each area. This segmentation allows individual temperature control of each region, enabling precise correction of local temperature non-uniformities that cannot be addressed by global supporting pin adjustment alone.
Solution Approach 2:
Each divided area has its own heating element and temperature control, allowing local temperature adjustment based on specific temperature distribution requirements. The offset calculating unit determines area-specific offsets to achieve uniform median temperatures across different regions, addressing local non-uniformities effectively.
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 approach significantly improves temperature uniformity over the semiconductor wafer surface, reducing the range of temperature distribution and ensuring that the median value of each area reaches the set temperature, thereby enhancing the manufacturing precision of semiconductor devices.
Implementation Method 1
a first temperature measurement unit which measures a temperature distribution over an entire top surface of the processing target object
Implementation Method 2
each divided area has a heating element corresponding to the divided area
Data Source
AI summary
A processing system includes a thermo viewer 51 which measures a temperature distribution over a top surface of a semiconductor wafer; a temperature measuring device 14 which measures, for each of divided areas of the semiconductor wafer, a temperature of a portion in the divided area; a median value calculating unit 202 which calculates, for each divided area, a median value of a temperature distribution of the divided area, based on the temperature distribution measured by the thermo viewer 51; an offset calculating unit 204 which calculates, for each divided area, a difference between the median value and the temperature of the portion as an offset; and a temperature control unit 205 which controls, for each divided area, the temperature of the divided area such that the median value becomes equal to a set temperature, based on the offset and the temperature measured by the temperature measuring device 14.