Wafer Mounting Table Temperature Correction Using Heat Transfer Gas
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Solution Overview
Problem
In semiconductor wafer processing, variations in thermal resistance due to deposits on the mounting table lead to non-uniform temperatures across wafers, affecting the consistency of semiconductor device characteristics, and frequent cleaning deteriorates throughput.
Innovation Solution
A temperature control method involving the supply of a heat transfer gas into the gap between the processing target object and the mounting table, measuring temperature variations, calculating correction values, and controlling heater power to achieve precise temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If cleaning process is performed frequently to remove deposits from mounting table, then temperature uniformity is improved, but productivity deteriorates
Solution Approach 1:
The patent introduces a preliminary measurement step before the actual measurement process. A test wafer is mounted on the mounting table and its temperature is measured in advance to detect thermal resistance variations caused by deposits. Based on this preliminary measurement, correction values are calculated and applied to the main measurement process, allowing the system to compensate for deposit effects without requiring frequent cleaning interruptions
Solution Approach 2:
The patent uses a test wafer as an intermediary object to indirectly measure the thermal resistance of the mounting table surface. Instead of directly measuring the mounting table's thermal properties, the system measures the temperature of a test wafer mounted on it, which reflects the thermal resistance conditions. This intermediary approach enables detection of deposit accumulation without contacting or disturbing the mounting table surface
2Measurement precision
If cleaning process is performed to remove deposits, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The system performs self-diagnosis by automatically measuring temperature variations using a test wafer and calculating correction values. The measurement apparatus autonomously detects thermal resistance changes caused by deposits and applies corrections without requiring external intervention or manual cleaning, thereby maintaining measurement precision while eliminating time loss to cleaning operations
Solution Approach 2:
The patent performs preliminary temperature measurements and correction value calculations before the actual production measurement process. By pre-characterizing the thermal resistance conditions using a test wafer and storing correction values, the system prepares in advance for potential measurement errors, eliminating the need for time-consuming cleaning interruptions during production
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 method suppresses non-uniformity in wafer temperatures, maintaining processing consistency while reducing the need for frequent cleaning and preserving throughput.
Implementation Method 1
a heat transfer gas is supplied into a gap between the processing target object and the mounting table... heat exchange between the processing target object and the mounting table through the heat transfer gas
Data Source
AI summary
A temperature control method of controlling a temperature of a semiconductor wafer mounted on a mounting table includes a supply process of supplying, in a state that a supply of a power to a heater configured to heat the mounting table is stopped or the power is maintained to be constant, a heat transfer gas into a gap between the semiconductor wafer and the mounting table; a measurement process of measuring a temperature variation of the mounting table due to heat exchange between the semiconductor wafer and the mounting table through the heat transfer gas; a calculation process of calculating a correction value based on the temperature variation of the mounting table; and a control process of starting the supply of the power and controlling the power such that the temperature of the mounting table reaches a target temperature corrected with the correction value.