CMP Slurry Delivery Velocity Control for Mixing Uniformity
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Solution Overview
Problem
Conventional ceria slurry delivery systems in CMP processes suffer from non-uniform mixing of abrasives and additives, leading to inconsistent polishing results and increased agglomeration, which causes scratches and variability in wafer surface planarization.
Innovation Solution
A slurry delivery system with velocity-changing members and buffering lines ensures uniform mixing of ceria abrasive and additives by altering flow velocities and reducing agglomeration, ensuring consistent distribution and improved mixing ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the abrasive and additives are delivered individually and mixed just before the CMP process (point-of-use delivery), then agglomeration of ceria material is reduced, but the mixing uniformity of the slurry deteriorates
Solution Approach 1:
The slurry delivery system is segmented into multiple independent feed lines (first feed line for abrasive, second feed line for additives) that converge at a mixing section. This segmentation allows each component to be delivered separately to prevent agglomeration while ensuring uniform mixing at the point of convergence through controlled flow velocities.
Solution Approach 2:
The system changes the flow velocity parameter of the abrasive stream using a velocity-changing member (such as a conical section or restrictor) to optimize mixing conditions. By adjusting the velocity of one component relative to another, the system achieves both prevention of agglomeration and uniform mixing distribution.
2Productivity
If the abrasive is delivered at high velocity through the feed line, then delivery efficiency is improved, but uniform mixing with additives deteriorates
Solution Approach 1:
The system dynamically adjusts the flow velocity of the abrasive stream through a velocity-changing member positioned at the convergence point. The abrasive is delivered at high velocity through the feed line for efficiency, then its velocity is modified at the mixing section to enable uniform mixing with additives without sacrificing overall delivery efficiency.
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 system achieves more uniform polishing across the wafer surface, reducing scratches and agglomeration, thereby enhancing CMP process reliability and standardization.
Implementation Method 1
a velocity-changing member which may change the first velocity to a second velocity
Implementation Method 2
a buffering line having a cross sectional area larger than the supply line and connected to the supply line... a flow velocity of the slurry may be reduced by the buffering line
Data Source
AI summary
A slurry delivery system, a chemical mechanical polishing (CMP) apparatus, and method for using the same are provided. An apparatus for supplying slurry to a polishing unit may include a first feed line through which an abrasive may be supplied at a first velocity. A velocity-changing member may be connected to the first feed line, and/or a velocity of the abrasive may be changed from the first velocity to. the second velocity different from the first velocity by the velocity-changing member. A second feed line may be connected to the velocity-changing member and/or an additive may be supplied through the second feed line. A supply line may be connected to the velocity-changing member. A slurry, which may be a mixture of the abrasive and/or the additive, may be supplied to a polishing unit through the supply line. Accordingly, the slurry may be more uniformly mixed and/or supplied to a polishing unit.