Retainer Ring Cooling via Fluid Spray in CMP
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Solution Overview
Problem
In chemical mechanical polishing (CMP) processes for semiconductor manufacturing, the retainer ring experiences increased abrasion due to frictional heat, leading to a shortened replacement cycle and economic losses, as the pressing force on the substrate is not uniform, causing temperature fluctuations.
Innovation Solution
A substrate polishing apparatus that includes a spray unit to maintain a constant temperature of the substrate carrier by spraying a fluid towards the retainer ring, with a temperature sensor and control unit to adjust the fluid application based on detected temperature changes, ensuring the retainer ring's surface temperature remains within a predetermined range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the retainer ring is used to support the substrate edge during polishing, then the substrate remains stable on the carrier, but frictional heat is generated between the retainer ring and polishing pad, causing increased abrasion and shortened replacement cycle
Solution Approach 1:
A cooling fluid is introduced as an intermediary substance between the retainer ring and the polishing pad environment. The fluid absorbs frictional heat generated during polishing, preventing excessive temperature rise that would accelerate retainer ring abrasion. This allows the retainer ring to maintain its structural integrity and functionality for longer periods while continuing to provide stable substrate support.
Solution Approach 2:
The temperature parameter of the retainer ring is actively controlled by introducing cooling fluid. By changing the thermal state of the retainer ring from high-temperature (causing rapid abrasion) to controlled-temperature (reducing abrasion), the replacement cycle is extended while maintaining the substrate support function.
2Duration of action of stationary object
If cooling fluid is sprayed toward the retainer ring to reduce temperature, then the retainer ring abrasion is reduced, but the device complexity increases due to additional cooling system components
Solution Approach 1:
The cooling fluid delivery system is integrated with the existing slurry delivery infrastructure. The same pump and delivery mechanism that supplies polishing slurry is used to supply cooling fluid, allowing the system to perform both polishing and cooling functions without requiring separate dedicated cooling equipment. This reduces device complexity while extending the retainer ring replacement cycle.
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 reduces the abrasion rate of the retainer ring, lengthening its replacement cycle and minimizing economic losses by maintaining a stable temperature, thus enhancing the efficiency and cost-effectiveness of the CMP process.
Implementation Method 1
a spray unit including a spray member configured to spray a fluid toward the substrate carrier
Implementation Method 2
spraying a fluid toward the substrate carrier... maintains a constant temperature of the substrate carrier
Implementation Method 3
the retainer ring comes into contact with the polishing pad and generates friction with the polishing pad, which generates heat from the retainer ring
Data Source
AI summary
A substrate polishing apparatus according to an example embodiment may include a substrate carrier configured to grasp and move a substrate, a polishing pad configured to come into contact with a polishing target surface of the substrate and polish the polishing target surface of the substrate, and a spray unit including a spray member configured to spray a fluid toward the substrate carrier.