Polyurea CMP Polishing Pad for High-Rate 3D NAND Planarization
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Solution Overview
Problem
Conventional chemical mechanical polishing (CMP) processes for 3D NAND manufacturing are bottlenecked by slow removal rates, particularly during the planarization of thick SiO2 overlayers, necessitating improved polishing pads that can operate at higher pressures and speeds without compromising performance.
Innovation Solution
A polishing pad comprising a polyurea layer with a soft phase of aliphatic fluorine-free and fluorinated aliphatic species, cured with a curative agent, featuring a hard phase with crystallinity and a melting point of at least 230°C, enhancing removal rates and stability under high pressure and speed conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional polishing pads are used for planarization of thick SiO2 overlayers, then the process can be completed, but the removal rate is slow and process time is lengthy
Solution Approach 1:
The patent modifies the polyurea polymer parameters by incorporating fluorinated aliphatic species into the soft phase and establishing specific crystallinity characteristics in the hard phase with a melting point of at least 230°C and ΔHf of at least 3 Joule/gram. These parameter changes enable the pad to operate at higher pressures and speeds, achieving improved removal rates and reduced process times for planarization of thick SiO2 overlayers in 3D NAND manufacturing
Solution Approach 2:
The patent creates a composite polyurea structure combining fluorinated aliphatic species in the soft phase with crystalline hard phase regions. This composite material structure provides both the flexibility needed for pad conformability and the thermal stability required for high-pressure, high-speed operation, thereby increasing removal rate without compromising pad performance
2Productivity
If higher pressure and speed are applied to increase removal rate, then productivity improves, but pad stability and performance may be compromised
Solution Approach 1:
The patent establishes specific parameter thresholds for the polyurea material: a melting point of at least 230°C and an enthalpy of formation (ΔHf) of at least 3 Joule/gram. These parameter changes provide the pad with enhanced thermal stability and structural integrity, enabling it to maintain its polishing performance and stability when operated at higher pressures and speeds without compromising reliability
Solution Approach 2:
The patent creates local quality differentiation within the polyurea structure by having a soft phase containing fluorinated aliphatic species for flexibility and conformability, while the hard phase provides structural stability and thermal resistance. This local quality separation allows the pad to simultaneously achieve high removal rates through high-pressure operation and maintain reliability through the stable hard phase structure
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 polyurea polishing pad achieves improved removal rates and stability, allowing for efficient planarization of substrates at higher pressures and speeds, reducing process times in CMP processes.
Implementation Method 1
the hard phase comprises crystallinity where the polyurea is characterized by a melting point of at least 230° C. and a ΔHf of at least 3 Joule/gram
Data Source
AI summary
A polishing pad suitable for polishing at least one of semiconductor, optical, magnetic or electromechanical substrates comprises: a polishing layer including a polyurea having a soft phase and a hard phase, the soft phase being a copolymer of aliphatic fluorine-free species and a fluorinated aliphatic species, the polyurea being cured with a curing agent where the hard phase comprises crystallinity where the polyurea is characterized by a melting point of at least 230° C. and a ΔHf of at least 3 Joule/gram as determined by Dynamic Scanning calorimetry of the polyurea