CMP Apparatus Magnetic Polishing Pad Slurry Positioning
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Solution Overview
Problem
Current chemical mechanical polishing apparatuses face challenges in efficiently polishing wafers due to uneven distribution and utilization of magnetic forces during the CMP process, leading to incomplete planarization and reduced polishing efficiency.
Innovation Solution
The apparatus incorporates a rotatable polishing platen with an electromagnet and a polishing pad featuring alternating magnetic and non-magnetic areas, where the upper polishing pad includes a second magnetic material to concentrate magnetic force, ensuring the slurry with magnetic material is effectively positioned for efficient polishing, particularly on high step portions of the wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional polishing pad with uniform material composition is used, then the structure is simple and easy to manufacture, but the magnetic force is unevenly distributed and insufficient to effectively position slurry on high step portions
Solution Approach 1:
The polishing pad is divided into multiple regions with different material properties: a first area with first magnetic material that overlaps the electromagnet for strong magnetic force, and a second area with non-magnetic material. This local differentiation enables precise control of slurry positioning on high step portions while maintaining structural manufacturability through modular material selection.
Solution Approach 2:
The polishing pad combines different magnetic and non-magnetic materials in a single composite structure. The first magnetic material in the first area works synergistically with the electromagnet to generate concentrated magnetic force, while the non-magnetic material in the second area provides contrast and defines the magnetic field distribution, enabling effective slurry positioning.
2Productivity
If magnetic material is uniformly distributed throughout the polishing pad, then the magnetic force is evenly applied, but the slurry cannot be effectively concentrated on the upper polishing pad for efficient polishing
Solution Approach 1:
The magnetic material is strategically localized to the first area that overlaps the electromagnet, creating a concentrated magnetic force zone. This local concentration causes the slurry containing magnetic material to be drawn to and positioned on the upper polishing pad, where it can effectively polish the wafer surface, particularly on high step portions.
Solution Approach 2:
The magnetic material in the slurry acts as an intermediary that responds to the magnetic field generated by the electromagnet and first magnetic material. This intermediary mechanism enables the slurry to be actively positioned and concentrated on the upper polishing pad through magnetic attraction, improving polishing efficiency.
3Force
If the polishing pad uses only non-magnetic material, then the structure is simple and magnetic interference is minimized, but the electromagnet cannot effectively position the slurry through magnetic force
Solution Approach 1:
The polishing pad incorporates magnetic material specifically in the first area that overlaps the electromagnet, creating a localized magnetic force generation zone. The non-magnetic material is used in the second area to provide contrast and define the magnetic field boundaries. This local differentiation enables effective slurry positioning while maintaining manufacturing simplicity through clear material zonation.
Solution Approach 2:
The polishing pad is segmented into distinct functional areas: the first area with magnetic material for electromagnetic interaction and slurry positioning, and the second area with non-magnetic material for structural support and magnetic field definition. This segmentation allows each region to perform its specific function optimally while simplifying the overall manufacturing process.
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 configuration enhances the distribution and effectiveness of the polishing slurry, leading to improved wafer planarization and increased efficiency in removing material from high step portions, thereby enhancing the overall CMP process.
Implementation Method 1
a polishing platen comprising an electromagnet, wherein the polishing platen is rotatable; a lower polishing pad positioned on the polishing platen, the lower polishing pad including a first area and a second area, the first area including a first magnetic material, and the second area including a non-magnetic material, wherein the first area overlaps the electromagnet
Implementation Method 2
a chemical mechanical polishing apparatus may include a magnetic material in a first area of a lower polishing pad and in an upper polishing pad, so that a slurry including a magnetic material may be positioned on the upper polishing pad
Implementation Method 3
The chemical mechanical polishing process may efficiently planarize films formed on a substrate by injecting a slurry composition containing polishing particles between the substrate and a polishing pad and causing friction between the substrate and the polishing pad
Data Source
AI summary
A chemical mechanical polishing apparatus includes a polishing platen that includes an electromagnet and is rotatable; a lower polishing pad that is positioned on the polishing platen, the lower polishing pad including a first area and a second area, the first area including a first magnetic material and the second area including a non-magnetic material, wherein the first area overlaps the electromagnet; an upper polishing pad that is positioned on the lower polishing pad, includes a second magnetic material, and overlaps the first area; and a polishing head configured to provide a wafer on the upper polishing pad and is rotatable.