CMP Platen Electric Field for Uniform Wafer Planarization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing chemical mechanical polishing (CMP) methods struggle to effectively planarize semiconductor wafers with uneven surface topography, leading to interference with subsequent photolithographic processes.
Innovation Solution
A CMP apparatus and method utilizing an electric field element between the platen and polishing pad to control the distribution of charged abrasive particles, applying varying voltages to attract and repel particles for improved planarization, combined with a multi-step polishing process using different slurry compositions and pad conditioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional CMP methods are used to planarize semiconductor wafers, then the polishing process can be performed, but the surface topography remains uneven and interferes with subsequent photolithographic processes
Solution Approach 1:
The patent applies parameter changes by varying the voltage applied to the electric field element during different stages of the polishing process. The voltage is adjusted to control the electrostatic attraction and repulsion of charged abrasive particles, thereby optimizing the polishing action for different regions and stages of planarization to achieve uniform surface quality.
Solution Approach 2:
The patent replaces conventional mechanical control of abrasive particle distribution with an electric field-based system. By applying voltage to an electric field element positioned between the platen and polishing pad, the system uses electrostatic forces to control the distribution and behavior of charged abrasive particles, achieving more precise control over the polishing mechanism.
2Productivity
If higher polishing pressure is applied to improve planarization, then polishing efficiency increases, but wafer defects and surface damage increase
Solution Approach 1:
The patent changes the electrical parameter (voltage) to control the polishing process. By adjusting the voltage applied to the electric field element, the system controls the electrostatic forces acting on charged abrasive particles, which in turn controls the polishing action. This allows optimization of polishing efficiency while minimizing wafer defects through precise electrical control rather than relying solely on mechanical pressure.
3Productivity
If abrasive particles are densely distributed on the polishing pad, then polishing speed increases, but uniformity of planarization decreases
Solution Approach 1:
The patent substitutes mechanical methods of abrasive particle distribution with an electric field-based control system. By applying voltage to the electric field element, the system uses electrostatic forces to control the distribution of charged abrasive particles on the polishing pad surface, enabling denser particle distribution for higher polishing speed while maintaining uniformity through controlled electrostatic attraction and repulsion.
Solution Approach 2:
The patent uses parameter changes by adjusting the voltage applied to the electric field element to control the distribution characteristics of abrasive particles. By varying the voltage parameter, the system can optimize both the density and uniformity of particle distribution on the polishing pad surface, achieving high polishing speed with maintained planarization quality.
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
Achieves a more uniform planarization of semiconductor wafers with reduced topographic variation, improving polishing efficiency and throughput while minimizing defects.
Implementation Method 1
applying varying voltages to attract and repel particles for improved planarization
Implementation Method 2
applying varying voltages to attract and repel particles for improved planarization
Implementation Method 3
The surface of a wafer may be planarized using a combination of mechanical and chemical mechanisms
Data Source
AI summary
A polishing platform of a polishing apparatus includes a platen, a polishing pad, and an electric field element disposed between the platen and the polishing pad. The polishing apparatus further includes a controller configured to apply voltages to the electric field element. A first voltage is applied to the electric field element to attract charged particles of a polishing slurry toward the polishing pad. The attracted particles reduce overall topographic variation of a polishing surface presented to a workpiece for polishing. A second voltage is applied to the electric field element to attract additional charged particles of the polishing slurry toward the polishing pad. The additional attracted particles further reduce overall topographic variation of the polishing surface presented to the workpiece. A third voltage is applied to the electric field element to repel charged particles of the polishing slurry away from the polishing pad for improved cleaning thereof.