Polishing Pad Even Tracking Zone Groove Design
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Solution Overview
Problem
Conventional polishing pads with concentric circular grooves result in uneven polishing rates across a substrate surface, particularly at the central portion, leading to reliability issues in device manufacturing.
Innovation Solution
A polishing pad with an even tracking zone and grooves arranged such that the largest distance from the rotational axis to one groove is approximately equal to the smallest distance to another groove, ensuring uniform polishing tracks and consistent polishing rates across the substrate surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If concentric circular grooves are used in the polishing pad, then the polishing pad structure is simple and easy to manufacture, but the polishing uniformity across the substrate surface deteriorates
Solution Approach 1:
The patent applies asymmetry by designing grooves with non-circular shapes (e.g., elliptical, rectangular, or irregular patterns) instead of conventional concentric circular grooves. This asymmetric groove configuration ensures that the substrate makes contact with both groove and non-groove portions uniformly across all regions during rotation, thereby achieving uniform polishing rates while maintaining manufacturing simplicity.
2Ease of operation
If the substrate rotates around its central axis on concentric circular grooves, then the relative motion is simple, but the polishing rate uniformity deteriorates especially at the central portion
Solution Approach 1:
The patent applies local quality by designing different groove patterns for different regions of the polishing pad. The groove configuration is optimized locally to ensure that each region of the substrate (center, middle, and outer portions) contacts both groove and non-groove portions appropriately, achieving uniform polishing rates across the entire substrate surface while maintaining simple rotational motion.
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 solution achieves better polishing uniformity and consistency across the substrate surface, enhancing the reliability of devices by maintaining uniform polishing rates, including at the central portion.
Implementation Method 1
Through the friction generated by the relative motion, a portion of the substrate surface is removed, such that the surface is planarized gradually
Data Source
AI summary
A polishing pad and a polishing method for polishing a substrate are described. The polishing pad includes a polishing layer and at least two grooves. The grooves form polishing tracks respectively. The polishing tracks collectively construct an even tracking zone. A better polishing uniformity of a substrate surface is achieved with the even tracking zone.