CMP Polishing Pad Thermal Conduction Through Deep-Groove Subpad
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Solution Overview
Problem
Existing chemical mechanical polishing (CMP) pads are thermally insulating, making it challenging to control polishing temperature and achieve uniform removal rates due to the lack of heat transfer capabilities.
Innovation Solution
A polishing pad with a polishing layer and a thermally conductive subpad layer, featuring recesses that extend deep into the polishing layer, facilitating heat transfer through the pad and enabling temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polishing pads are made from porous polymeric materials, then the pads provide effective polishing performance, but the pads become thermally insulating which makes temperature control difficult
Solution Approach 1:
The polishing pad is divided into multiple functional layers: a polishing layer for material removal and a subpad layer with enhanced thermal conductivity for heat management. This segmentation allows each layer to specialize in its primary function while working together as an integrated system.
Solution Approach 2:
The pad uses a composite structure combining porous polymeric materials in the polishing layer with thermally conductive materials in the subpad layer. This composite approach integrates the polishing effectiveness of porous polymers with the thermal management capabilities of conductive materials.
2Device complexity
If the polishing pad uses thermally insulating polymeric materials, then the pad structure remains simple, but heat transfer through the pad is insufficient leading to thermal fluctuations
Solution Approach 1:
The pad is segmented into a polishing layer and a thermally conductive subpad layer, distributing functions across layers to manage both structural simplicity and thermal performance.
Solution Approach 2:
Different regions of the pad have different thermal properties: the polishing layer maintains low thermal conductivity for structural simplicity, while the subpad layer provides high thermal conductivity for heat transfer, creating localized functional zones.
3Temperature
If deep recesses are created in the polishing layer, then thermal contact with the subpad is improved, but the polishing layer structure becomes more complex
Solution Approach 1:
The recesses in the polishing layer are formed with curved, dome-like shapes rather than sharp angular geometries. This curvature facilitates gradual thermal contact with the subpad while maintaining manufacturing feasibility and avoiding overly complex structures.
Solution Approach 2:
The polishing layer utilizes its inherent porous structure to allow thermal pathways to extend through the material to the recesses, enhancing thermal contact with the subpad without requiring solid structural modifications.
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
The pad provides stable temperature profiles during polishing, leading to consistent removal rates and improved polishing performance by managing thermal fluctuations.
Implementation Method 1
The subpad layer has a thermal conductivity of 1 to 35 Watts/m-K
Data Source
AI summary
A polishing pad for chemical mechanical polishing comprises a polishing layer and an adjacent subpad layer. The polishing layer includes a polishing surface, a polishing layer interface surface opposite the polishing surface, a polishing layer thickness extending from the polishing surface to the polishing layer interface surface, and recesses extending from the polishing layer surface toward the polishing layer interface surface. A depth of the recesses is at least 80% the polishing layer thickness. The subpad layer has a subpad interface surface adjacent to the polishing layer interface surface and a bottom surface opposite the subpad interface surface. The subpad layer has a thermal conductivity of 1 to 35 Watts/m-K. The combination of the deep grooves in the top layer and the thermal conductivity of the subpad layer can facilitate thermal management at the polishing interface during polishing of a substrate.