CMP Polishing Head Membrane with Pneumatic Partitions
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Solution Overview
Problem
Conventional chemical mechanical polishing (CMP) apparatuses face challenges in achieving uniform polishing of substrates due to uneven pressure distribution, leading to non-uniform thickness and precision issues in multi-layered semiconductor devices.
Innovation Solution
The polishing head incorporates a membrane with a unique design featuring partitions and clamps that distribute pneumatic pressure uniformly across the substrate, using air channels to control pressure and maintain even contact, ensuring consistent polishing across the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional polishing head with a simple membrane structure is used, then the device complexity is low, but the manufacturing precision deteriorates due to uneven pressure distribution
Solution Approach 1:
The membrane is divided into multiple pressing portions by partitions, with each portion independently controllable through pneumatic pressure. This segmentation allows different regions of the membrane to apply adjusted pressure to different areas of the substrate, achieving uniform pressure distribution and improving manufacturing precision.
Solution Approach 2:
Each pressing portion of the membrane can be controlled to have different pneumatic pressure levels, allowing local adjustment of pressing force. This enables optimization of pressure distribution across the substrate surface, with higher pressure applied where needed and lower pressure where the substrate requires less force, thereby improving uniformity of thickness.
2Manufacturing precision
If pneumatic pressure is applied to the membrane, then the manufacturing precision improves through even pressure distribution, but the device complexity increases due to additional components
Solution Approach 1:
Pneumatic pressure is introduced to control the membrane's pressing force. Air channels are integrated into the base assembly to deliver controlled pneumatic pressure to the membrane, enabling precise control of the pressing force without requiring complex mechanical adjustment mechanisms.
Solution Approach 2:
The pneumatic pressure applied to the membrane can be adjusted as a control parameter to optimize the pressing force. By changing the pressure level, the system can adapt to different substrate thickness requirements and achieve uniform polishing without mechanical reconfiguration.
3Manufacturing precision
If the membrane is made flexible to conform to substrate, then the manufacturing precision improves, but the reliability deteriorates due to potential membrane failure
Solution Approach 1:
The membrane is designed as a flexible thin film that can conform to the substrate surface while maintaining structural integrity. The flexibility allows the membrane to adapt to substrate variations and maintain uniform contact, while the thin film structure reduces stress concentration and improves durability.
Solution Approach 2:
The membrane structure is designed to accommodate and cushion potential stress concentrations before they can cause failure. The flexible nature of the membrane allows it to absorb and distribute mechanical stresses, preventing crack propagation and maintaining reliability during operation.
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 design ensures even polishing of substrates, improving precision and reducing edge wear, thereby maintaining uniform thickness and enhancing the overall polishing process efficiency.
Implementation Method 1
a curved portion configured to expand by pneumatic pressure
Implementation Method 2
a pressing portion configured to adsorb and press a substrate
Data Source
AI summary
A polishing head of a chemical mechanical polishing apparatus includes a housing moving up and down, a base assembly connected to a bottom of the housing to support the housing, a membrane on a bottom of the base assembly and a retainer ring surrounding the membrane and connected to the bottom of the base assembly, the membrane including a pressing portion to adsorb and press a substrate, a first partition on the pressing portion and extending from an edge of the pressing portion along a height direction, a first horizontal extending portion extending from an upper end portion of the first partition toward a center of the membrane, and a second horizontal extending portion from the upper end portion of the first partition toward the center of the membrane, the second horizontal extending portion being above the first horizontal extending portion and including a curved portion expanding by pneumatic pressure.