Di-block Polymer Lithography for Phase Change Memory Heater
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Solution Overview
Problem
Phase change memory devices require large currents for programming and erasing, leading to high power dissipation and increased cell size, making it difficult to achieve high integration density due to the large current requirements.
Innovation Solution
The method involves forming a di-block polymer layer on a substrate, where the second phase is removed to create a pore and expose the interlayer dielectric, allowing for the formation of a polymer spacer and a heater electrode with reduced dimensions, which reduces the current needed to convert the phase change material's state, thereby minimizing power dissipation and cell size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Joule heat is used to convert the state of the phase change material, then the phase change material can be switched between amorphous and crystalline states, but large current is required leading to high power dissipation
Solution Approach 1:
The patent changes the physical parameters of the heater electrode by reducing its cross-sectional area (width and thickness) while maintaining length, thereby increasing resistance. This parameter change allows the heater to operate at higher resistance with reduced current requirements, directly addressing the power dissipation issue while maintaining phase change material state conversion capability
Solution Approach 2:
The patent applies local quality by creating a heater electrode with non-uniform cross-section (varying width along its length) and optimized thickness distribution. The heater has different dimensions at different locations to concentrate heat efficiently at the phase change material interface, improving heating efficiency and reducing overall power dissipation requirements
2Reliability
If large current is used for programming and erasing operations, then the phase change material state can be changed, but the plan area occupied by the switching element increases
Solution Approach 1:
The patent changes the geometric parameters of the heater electrode to increase resistance (reduced width and thickness), which enables operation at lower current. This parameter optimization allows the same program/erase functionality to be achieved with smaller current, thereby reducing the required cell area and enabling higher integration density
Solution Approach 2:
The patent optimizes the heater electrode in multiple dimensions (length, width, thickness) rather than just scaling uniformly. By adjusting the vertical dimension (thickness) and horizontal dimensions (width profile) independently, the design achieves high resistance in a compact footprint, reducing the plan area occupied by the switching element
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 approach reduces power dissipation and cell size, enabling the creation of highly integrated phase change memory devices by increasing the resistance of the heater electrode and minimizing the area occupied by current-controlled components.
Implementation Method 1
The di-block polymer layer is divided into a first phase to which the first polymer blocks are bound and a second phase to which the second polymer blocks are bound. The first phase and the second phase may be divided, for example, by annealing the di-block polymer layer.
Implementation Method 2
The second phase may be removed, for example, by performing a developing process on the di-block polymer using a developer, where a solubility of the first polymer block to the developer is lower than a solubility of the second polymer block to the developer.
Implementation Method 3
If a phase change material is rapidly cooled after being heated at a temperature higher than a melting temperature for a short time, it exhibits an amorphous state.
Implementation Method 4
If a phase change material is slowly cooled after being heated at a temperature higher than a crystallization temperature and lower than a melting temperature for a long time, it exhibits a crystalline state.
Implementation Method 5
Conventionally, Joule heat is used to convert the state of the phase change material to an amorphous state or a crystalline state. The Joule heat is generated by flowing current through the phase change material and through a conductive plug which is in contact with the phase change material.
Data Source
AI summary
A method of forming a semiconductor device is provided. An interlayer dielectric is formed on a substrate. A di-block polymer layer that includes a plurality of first polymer blocks and a plurality of second polymer blocks is formed on the interlayer dielectric. The di-block polymer layer is divided into a first phase to which the first polymer blocks are bound and a second phase to which the second polymer blocks are bound. The second phase is removed so that at least part of the first phase remains in place, where the remaining first phase defines at least part of a pore. The interlayer dielectric that is exposed beneath the pore is etched to form an opening. The opening may have a smaller width than the minimum feature size that a photolithography process is capable of resolving. As a result, a linewidth of an electrode that may be formed to fill the opening may be reduced.