Polishing Pad Temperature Control via Non-Contact Heat Exchanger
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Solution Overview
Problem
Conventional pad-temperature regulating apparatuses for polishing substrates face challenges in maintaining optimal surface temperature of polishing pads, leading to contamination and defects like scratches due to dirt accumulation on the heat exchanger and complex control methods.
Innovation Solution
A pad-temperature regulating apparatus with a heat exchanger positioned above the polishing pad, using a controller to adjust the distance between the heat exchanger and the pad, and employing a machine learning model to optimize temperature control, preventing dirt accumulation and simplifying the control process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the heat exchanger is placed into contact with the polishing pad to regulate temperature, then the temperature control effectiveness is improved, but dirt and abrasion powder accumulate on the heat exchanger causing contamination and scratches on the substrate
Solution Approach 1:
The patent extracts the heat exchanger from direct contact with the polishing pad by positioning it above the pad at a predetermined distance. This separation prevents dirt and abrasion powder from accumulating on the heat exchanger surface, eliminating the source of contamination and scratches while maintaining temperature regulation capability through non-contact thermal coupling.
Solution Approach 2:
The patent introduces air as an intermediary medium between the heat exchanger and the polishing pad. The heat exchanger transfers thermal energy to the pad through the air gap rather than direct contact, allowing temperature regulation while preventing direct physical contact that would cause dirt accumulation and substrate defects.
2Measurement precision
If both heating liquid flow rate and cooling liquid flow rate are controlled simultaneously to regulate pad temperature, then temperature precision is improved, but the control system becomes complicated and responsiveness decreases
Solution Approach 1:
The patent extracts one of the two conflicting control parameters (either heating liquid flow rate or cooling liquid flow rate) from the simultaneous control system. By controlling only a single parameter while maintaining the other at a fixed value, the system achieves temperature regulation with simplified control logic and improved responsiveness, eliminating the complexity of coordinating two conflicting control actions.
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 solution effectively maintains the polishing pad's surface temperature at a target value without causing defects and improves control responsiveness, preventing contamination and enhancing polishing efficiency.
Implementation Method 1
a heat exchanger capable of contacting a surface of the polishing pad
Implementation Method 2
a pad-temperature measuring device for measuring the surface temperature of the polishing pad
Data Source
AI summary
A pad-temperature regulating device is disclosed, which can improve a responsiveness of a control for a surface temperature of a polishing pad and regulate the surface temperature of the polishing pad without causing defects, such as scratches, on the substrate. The pad-temperature regulating apparatus includes: a heat exchanger disposed above the polishing pad, whose temperature is maintained at a predetermined temperature; a pad-temperature measuring device configured to measure the surface temperature of the polishing pad; a distance sensor configured to measure a separation distance between the polishing pad and the heat exchanger; an elevating mechanism for moving the heat exchanger vertically with respect to the polishing pad; and a controller configured to control operation of the elevating mechanism based on measured values of the pad-temperature measuring device.