Polishing Pad Pore Control via Surfactant Balance
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Solution Overview
Problem
Conventional methods for manufacturing chemical mechanical polishing pads face challenges in controlling pore size and pore size distribution, leading to difficulties in achieving enhanced polishing performance and manufacturability.
Innovation Solution
A method involving the application of droplets of a liquid polymer containing nonionic and ionic surfactants to form a solid polymer with controlled pore size, where the nonionic surfactant facilitates pore growth and the ionic surfactant limits growth, forming a network of interconnected pores, which is repeated to increase thickness and cured to form a polishing pad with precise pore control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional mechanical foaming method is used to manufacture polishing pads, then the polishing pad can be formed with spherical cells, but the pore size and pore size distribution cannot be controlled precisely
Solution Approach 1:
The patent changes the chemical parameters of the liquid polymer by adding specific concentrations of nonionic surfactant (0.1-10 wt%) and ionic surfactant (0.1-10 wt%). This chemical parameter modification enables precise control of pore size and distribution during the drying process, transforming the uncontrolled mechanical foaming into a chemically-controlled pore formation process.
Solution Approach 2:
The patent introduces surfactants as intermediary substances that mediate between the liquid polymer and the forming pores. The nonionic surfactant facilitates pore growth while the ionic surfactant limits pore growth, creating a balanced controlled pore structure without requiring complex mechanical foaming equipment.
2Productivity
If conventional mechanical foaming method is used, then polishing pad can be manufactured, but fouling issues occur that decrease manufacturing efficacy
Solution Approach 1:
The patent replaces the mechanical foaming system with a chemical self-organization system. Instead of using mechanical equipment to create pores, the liquid polymer spontaneously forms pores during drying through surfactant-mediated phase separation, eliminating the fouling associated with mechanical foaming components.
3Manufacturing precision
If conventional methods are used, then polishing pad can be formed, but the groove pattern quality is insufficient requiring additional machining
Solution Approach 1:
The patent performs preliminary action by forming the groove pattern directly during the pore formation process in the liquid polymer. The surfactant-controlled pore formation simultaneously creates both the porous structure and the groove pattern, eliminating the need for subsequent machining operations.
4Reliability
If conventional methods are used, then polishing pad can be manufactured, but pore size distribution is uncontrolled affecting polishing performance
Solution Approach 1:
The patent implements feedback control through the interaction between nonionic and ionic surfactants. The nonionic surfactant promotes pore growth while the ionic surfactant restricts it, creating a self-regulating system that maintains optimal pore size distribution for consistent polishing performance across the pad.
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 method enhances the quality of the polishing pad's groove pattern, eliminates the need for machining, and provides a broader compositional window, resulting in improved polishing performance and manufacturability by precisely controlling pore size and distribution.
Implementation Method 1
the liquid polymer containing a nonionic surfactant, the nonionic surfactant having a concentration sufficient to facilitate growth of pores within the liquid polymer
Implementation Method 2
an ionic surfactant having a concentration sufficient to limit growth of the pores within the liquid polymer
Implementation Method 3
solidifying the droplets of liquid polymer against the substrate into a solid polymer containing a plurality of pores
Data Source
AI summary
The invention is to a method of manufacturing a polishing pad suitable for planarizing at least one of semiconductor, optical and magnetic substrates. The method includes applying droplets of a liquid polymer against a substrate to form a plurality of pores. The liquid polymer contains a nonionic surfactant, the nonionic surfactant has a concentration sufficient to facilitate growth of pores within the liquid polymer and an ionic surfactant has a concentration sufficient to limit growth of the pores within the liquid polymer. Curing the solid polymer forms a polishing pad with final size of the plurality of pores controlled by the concentration of nonionic surfactant and ionic surfactants.