Axial Slurry Feed CMP Pad for Localized Wafer Planarization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing chemical mechanical planarization (CMP) processes struggle with achieving high-resolution, localized planarization of uneven semiconductor surfaces due to the large size difference between the polishing pad and wafer, leading to inefficiencies in material removal and surface uniformity.
Innovation Solution
A rotatable polishing pad with a slurry delivery conduit through its axial center dispenses polishing slurry directly beneath the pad, synchronized with its rotation speed, to enable localized polishing of substrate surfaces, using a smaller pad diameter and controlled pressure application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a large rotating table with a large polishing pad is used for CMP, then the polishing area is large and processing capacity is high, but the resolution for localized planarization is poor and material removal uniformity deteriorates
Solution Approach 1:
The large polishing pad is segmented into multiple smaller independent polishing regions or pads. Each small pad can be independently controlled to polish specific areas of the wafer, enabling localized planarization with high resolution while maintaining the ability to process large wafers through multiple zones.
Solution Approach 2:
Different regions of the polishing system are given different properties - small pads for high-resolution localized work, large pads for bulk planarization. The system adapts the polishing characteristics to the specific requirements of different wafer regions, achieving both high resolution and adequate coverage.
2Productivity
If slurry is introduced onto the top of the rotating table, then the polishing process is simple and continuous, but the material removal rate and uniformity are insufficient for advanced materials
Solution Approach 1:
The polishing slurry is pre-delivered through conduits to specific locations on the polishing pad or wafer surface before the polishing contact is made. This ensures optimal slurry distribution and activation at the exact moment and location where polishing occurs, enhancing both material removal rate and surface uniformity for advanced semiconductor materials.
Solution Approach 2:
Slurry delivery conduits act as intermediaries to transport and precisely position the polishing slurry at the pad-wafer interface. This controlled delivery mechanism ensures adequate slurry supply to high-speed polishing zones while preventing excess slurry in areas where it would reduce effectiveness, thereby improving both productivity and precision.
3Manufacturing precision
If the polishing pad diameter is small for high-resolution work, then the planarization precision is improved, but the processing capacity and productivity decrease
Solution Approach 1:
The polishing system is designed with multiple small pads that can be independently activated or combined. When high resolution is needed, individual small pads are used for targeted areas. When processing capacity is prioritized, multiple pads work simultaneously or the system switches to a larger pad configuration, making the system universally capable of both high-precision and high-volume tasks.
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 enhances material removal rate and uniformity, achieving high-resolution planarization of advanced semiconductor materials like SiC and Ge, with improved polishing efficiency and surface flatness.
Implementation Method 1
The method involves a combination of both mechanical and chemical processes to remove unwanted material and render the surface of the process wafer flat
Implementation Method 2
The method involves a combination of both mechanical and chemical processes to remove unwanted material
Data Source
AI summary
A polishing apparatus, specifically for performing chemical mechanical planarization on an object such as a substrate, which may be a semiconductor wafer. The polishing apparatus may include a rotatable polishing pad having an axial center of rotation and a slurry delivery conduit configured to introduce polishing slurry through said axial center of rotation. The polishing slurry may be configured to be dispensed directly beneath the rotatable polishing pad to enable localized polishing of a surface of a substrate located below or beneath the rotatable polishing pad.