CMP Nozzle Positioning for Polishing Rate Uniformity
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Solution Overview
Problem
Existing polishing devices with single tube nozzles for supplying polishing liquid to substrates during CMP processes face challenges in achieving uniform polishing rates due to non-uniform distribution of the polishing liquid, leading to variations in polishing rates across the substrate surface.
Innovation Solution
A polishing device equipped with a liquid injection nozzle that injects the polishing liquid in a fan shape, a nozzle moving device to adjust its position radially, and an operation control unit that calculates and adjusts the optimal supply position based on the correlation between the polishing liquid supply and the polishing rate distribution to ensure uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single tube nozzle is used to supply polishing liquid, then the device structure is simple, but the polishing liquid distribution becomes non-uniform causing large distribution in flow rate
Solution Approach 1:
The single tube nozzle is divided into multiple nozzles arranged in an arc shape. Each nozzle supplies polishing liquid to a specific region, and the collective effect of multiple nozzles achieves uniform coverage across the polishing pad surface, eliminating the large flow rate distribution problem of a single nozzle.
Solution Approach 2:
The nozzles are arranged in an arc configuration rather than a linear or radial arrangement. This arc arrangement in the angular dimension allows the polishing liquid to be distributed uniformly across the polishing pad surface, optimizing the flow rate distribution while maintaining structural simplicity.
2Ease of operation
If the polishing liquid is supplied at a fixed position, then the device operation is simple, but the polishing rate distribution within the substrate becomes non-uniform
Solution Approach 1:
The nozzle assembly is designed to rotate in the angular direction during the polishing process. This dynamic movement allows the fixed-structure nozzle system to effectively supply polishing liquid to different radial positions on the polishing pad, achieving uniform polishing rate distribution across the substrate without requiring complex individual nozzle positioning mechanisms.
3Area of stationary object
If the polishing liquid is supplied to the outer peripheral side of the polishing pad, then the liquid supply covers the edge region, but a large amount of polishing liquid is discharged to the outside of the polishing pad
Solution Approach 1:
Each nozzle in the arc arrangement is positioned and oriented to supply polishing liquid to its specific local region on the polishing pad. The arc configuration ensures that the liquid supply is concentrated on the pad surface rather than spilling outward, optimizing both coverage and liquid utilization efficiency.
Data Source
AI summary
An operation control unit includes a storage device storing a program which includes commands of: obtaining a correlation between a supply position of the polishing liquid in the radial direction of the polishing pad using the liquid injection nozzle and an average polishing rate of the substrate and an distribution of the polishing rate within the substrate; determining a movable range of the liquid injection nozzle according to a predetermined range of an allowable average polishing rate and the correlation between the supply position of the polishing liquid and the average polishing rate; determining an optimal supply position of the polishing liquid from the correlation between the supply position of the polishing liquid and the distribution of the polishing rate within the substrate within the determined movable range of the liquid injection nozzle; and moving the liquid injection nozzle to the determined supply position to polish the substrate.