Movable Slurry Outlet for CMP Uniformity
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Solution Overview
Problem
Conventional chemical mechanical polishing (CMP) systems face challenges in maintaining process stability and predicting optimal consumable replacement due to complex parameter control and slurry distribution issues, leading to reduced yield and increased costs.
Innovation Solution
A CMP system with a controllably movable polishing head and slurry delivering unit that allows for locally varying slurry supply based on process parameters such as slurry type, thickness, temperature, and wafer curvature, using a controllably movable slurry outlet to optimize slurry distribution over the polishing pad.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional CMP systems use fixed slurry delivery, then the system structure is simple, but slurry distribution becomes non-uniform leading to process instability
Solution Approach 1:
The slurry outlet is made movable rather than fixed, allowing dynamic adjustment of slurry delivery position. The outlet can move in radial and/or tangential directions relative to the polishing pad, enabling real-time optimization of slurry distribution patterns to maintain uniformity and process stability.
Solution Approach 2:
The system incorporates sensors to detect slurry distribution uniformity and polishing pad conditions, feeding this information back to the control system. Based on feedback signals, the control system adjusts the outlet position and slurry flow rate to maintain optimal slurry distribution and remove densified regions.
2Productivity
If slurry is continuously supplied to polishing pad, then removal rate is maintained, but slurry densification occurs reducing effectiveness
Solution Approach 1:
The slurry outlet periodically changes position and delivery patterns to prevent continuous accumulation of particles in the same region. By moving the outlet in controlled cycles and adjusting flow rates periodically, the system refreshes slurry distribution and prevents densification while maintaining overall removal rate.
Solution Approach 2:
The system identifies and targets densified slurry regions for removal or replacement. By detecting areas with excessive particle accumulation, the system adjusts outlet positioning to deliver fresh slurry to these regions, effectively discarding the densified slurry and recovering polishing effectiveness.
3Manufacturing precision
If slurry outlet remains stationary, then device complexity is low, but uniform slurry distribution cannot be achieved
Solution Approach 1:
The slurry outlet is equipped with drive mechanisms enabling movement in radial and/or tangential directions. This dynamic positioning capability allows the outlet to traverse different regions of the polishing pad, ensuring uniform slurry distribution across the entire surface while maintaining relatively simple mechanical structures.
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 process stability and reduces consumable costs by optimizing slurry distribution, improving the reliability and efficiency of the CMP process.
Implementation Method 1
the reaction product, such as a metal oxide, is then mechanically removed with abrasives contained in the slurry and/or the polishing pad
Implementation Method 2
A densification of the slurry within the voids occurs due to the absorbed particles that have been removed from the substrate surface and accumulated in the slurry
Data Source
AI summary
A system and a method of operating a chemical mechanical polishing (CMP) system comprises a slurry delivering unit configured for locally varying the supply of slurry while polishing the substrate. To this end, the slurry delivering unit may comprise at least one slurry outlet over a polishing pad of the CMP system, wherein the at least one slurry outlet is controllably movable to distribute slurry over the polishing pad.