Wafer Temperature Control via Gas Flow Adjustment
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Solution Overview
Problem
Existing wafer cooling methods during chemical mechanical polishing are ineffective, leading to inaccurate temperature control and reduced polishing accuracy due to inadequate heat dissipation.
Innovation Solution
A wafer temperature control system that includes a polishing head with gas passages for introducing cooling gas, a monitoring module for real-time temperature measurement, and a control module that adjusts the flow rate and introduction duration of the cooling gas to maintain optimal wafer temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If polishing is performed for a long time to remove thin film, then removal rate increases, but heat accumulates and affects wafer state and polishing accuracy
Solution Approach 1:
A temperature control plate is introduced as an intermediary component between the polishing pad and the polishing table. This plate actively removes heat from the wafer during polishing by conducting heat away through its structure, thereby maintaining stable wafer temperature and polishing accuracy while enabling prolonged polishing operations for higher removal rates
Solution Approach 2:
The system changes the thermal parameters of the polishing system by introducing a temperature control plate with specific thermal conductivity properties. This plate actively manages heat transfer parameters during polishing, allowing the process to maintain stability over extended periods while achieving higher material removal rates
2Temperature
If platen is cooled by water circulation, then platen temperature decreases, but cooling effect on pad and wafer is insufficient
Solution Approach 1:
Instead of directly cooling the platen and relying on heat conduction through multiple interfaces, the invention introduces a temperature control plate as an intermediary that directly contacts both the wafer and the cooling system. This intermediary provides a more efficient and direct heat transfer path, significantly improving the cooling effect on the wafer while maintaining platen temperature stability
3Loss of energy
If DIW cooling is used during pad flushing, then some heat is removed, but cooling effect is poor and only auxiliary
Solution Approach 1:
The temperature control plate serves as a primary cooling intermediary during polishing operations, providing reliable and efficient heat removal. This eliminates the need to rely on auxiliary DIW cooling during pad flushing, as the plate maintains adequate temperature control throughout the polishing process, improving overall cooling reliability
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 system effectively reduces wafer temperature fluctuations, enhancing the accuracy and efficiency of the chemical mechanical polishing process by using real-time temperature feedback to adjust cooling gas flow and duration.
Implementation Method 1
a temperature of a wafer is adjusted by introducing a cooling gas into the gas passages
Data Source
AI summary
The present application provides a wafer temperature control system, including: a wafer polishing apparatus, a control module, an adjustment module, and a monitoring module. The wafer polishing device includes a polishing head having gas passages, a temperature of a wafer is adjusted by introducing a cooling gas into the gas passages. The monitoring module is configured to measure the temperature of the wafer in real time and send a generate temperature signal to the control module. The control module generates an adjustment signal used for adjusting a flow rate and introduction duration of the cooling gas. The adjustment module adjusts the flow rate and the introduction duration of the cooling gas introduced into the gas passages. According to the present application, the problem that the existing wafer cooling method cannot achieve a good cooling effect and thus leads to an impact on wafer polishing accuracy is solved.