Flexible Membrane Carrier for CMP Wafer Cooling
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Solution Overview
Problem
Existing chemical mechanical planarization (CMP) systems face challenges in improving wafer carrier performance to prevent wafer breakage and non-uniformity during processing, particularly when handling harder materials like silicon carbide.
Innovation Solution
The CMP system incorporates a substrate carrier head with a resilient membrane that allows for liquid cooling and pressure distribution, along with a chamber configuration for atomizing liquids and cleaning, to enhance wafer handling and temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wafer carrier is used during CMP processing, then wafer holding and pressure application are achieved, but wafer breakage and non-uniformity occur due to interaction between wafer and carrier
Solution Approach 1:
The patent employs a flexible membrane as the wafer carrier instead of rigid structures. This flexible membrane can conform to the wafer surface and distribute pressure uniformly, reducing stress concentrations that cause breakage while maintaining effective contact for polishing.
Solution Approach 2:
The patent uses fluid pressure (pneumatic or hydraulic) to apply and distribute force on the wafer through the flexible membrane. This allows uniform pressure distribution across the wafer surface, preventing localized stress that leads to breakage and non-uniform polishing.
2Productivity
If polishing is performed on harder materials like silicon carbide, then removal rate increases, but heat generation and wafer breakage risk increase
Solution Approach 1:
The patent introduces fluid flow through the flexible membrane during polishing to provide active cooling. The flowing fluid carries away heat generated during polishing of hard materials like silicon carbide, maintaining lower temperatures that prevent wafer breakage while allowing higher removal rates.
Solution Approach 2:
The patent changes the physical state and flow parameters of the cooling fluid to optimize heat removal. By controlling fluid flow rate, pressure, and temperature, the system effectively manages thermal load during high-productivity polishing of hard materials.
3Temperature
If atomized liquid is applied to cool the polishing pad, then temperature control improves, but liquid containment and exhaust become complex
Solution Approach 1:
The flexible membrane serves dual functions: as the wafer carrier and as a containment barrier for atomized cooling liquid. This eliminates the need for separate containment structures, simplifying the overall system while maintaining effective temperature control of the polishing pad.
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 reduces wafer breakage and non-uniformity by providing uniform pressure and cooling, allowing for higher removal rates and improved surface quality during CMP processes, especially for harder materials like silicon carbide.
Implementation Method 1
The atomized liquid can be configured to cool the polishing pad via evaporative cooling
Implementation Method 2
The outer chamber can be configured to have a lower pressure than the inner chamber
Data Source
AI summary
Containment and exhaust systems for substrate polishing components are disclosed. In one aspect, a substrate carrier head, includes a polishing pad, a substrate carrier head configured to retain a wafer against the polishing pad, an atomizer configured to atomize a liquid and spread a layer of the atomized liquid over a surface area of the polishing pad, and a chamber configured to contain and exhaust the atomized liquid.