Nanoporous CMP Wafer Cleaning Brush for Particle Defect Reduction
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Solution Overview
Problem
Conventional post-CMP cleaning processes suffer from particle defect issues due to slurry abrasives, polish wastes, and byproducts, particularly affecting advanced technology nodes with feature sizes of 10 to 100 nm.
Innovation Solution
Development of brushes with PVA-copolymer or other polymers, including cellulose, lignin, nylon, or polytetrafluoroethylene backbone, and designed nanometer-scale pores, along with functional groups to enhance brush-particle affinity, improving the removal of particles up to 100 nm in size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sponges are used for post-CMP cleaning, then the cleaning process is simple and cost-effective, but particle defects remain on the wafer surface
Solution Approach 1:
The patent applies porous materials by creating a brush with controlled pore structure where pores range from 0.1 to 10 micrometers in size. This porous structure allows the brush to effectively trap and remove particles in the 10-100 nm range from the wafer surface while maintaining mechanical cleaning action, thereby reducing particle defects without compromising cleaning effectiveness
Solution Approach 2:
The patent uses composite materials by combining polymer base material with controlled pore structures and functional groups. This composite approach creates a brush material that has both the mechanical properties needed for effective cleaning and the surface properties needed to prevent particle adhesion, resolving the contradiction between cleaning effectiveness and particle defect reduction
2Manufacturing precision
If feature sizes are reduced to advance technology nodes, then device performance is improved, but particle defects from CMP residue become more significant
Solution Approach 1:
The patent applies parameter changes by controlling the pore size parameter of the brush material to be 0.1 to 10 micrometers, which is specifically optimized to capture particles in the 10-100 nm range. This parameter optimization allows the cleaning process to be effective at advanced technology nodes where even tiny particles can cause defects, thereby maintaining manufacturing precision while reducing harmful particle effects
3Productivity
If brushes with higher porosity are used to remove tiny particles, then particle removal efficiency is improved, but brush structure complexity increases
Solution Approach 1:
The patent applies porous materials with a controlled pore size distribution (0.1 to 10 micrometers) that provides high porosity for effective particle removal while maintaining a manageable brush structure. The porous structure is integrated into the brush material itself rather than requiring complex multi-component assemblies, thereby achieving high particle removal efficiency without excessive structural complexity
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
Enhances post-CMP cleaning performance by reducing the amount of tiny particles remaining on wafers, thereby improving yield and productivity.
Implementation Method 1
surface engineering brushes with improved materials such as PVA-copolymer or other polymers with functional groups and nanometer-scaled pores, which increase brush-particle affinity
Data Source
AI summary
Brushes for cleaning wafers after a Chemical Mechanical Polishing (CMP) process and methods for fabricating such brushes are provided. An exemplary method for fabricating a brush for cleaning wafers after a Chemical Mechanical Polishing (CMP) process includes forming a brush configured for contacting the wafers; and, while forming the brush, controlling formation of pores within the brush to a maximum pore dimension, wherein the maximum pore dimension is 1000 nanometers (nm).