Perpendicular MTJ for MRAM Top Electrode Landing
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Solution Overview
Problem
The manufacturing of magnetoresistive random-access memory (MRAM) cells with traditional in-plane magnetic tunneling junctions faces challenges due to limited space for landing top electrodes, requiring thick dielectric layers that result in poor curing and chemical mechanical polishing (CMP) uniformity issues, leading to increased costs and complexity.
Innovation Solution
The use of perpendicular magnetic tunneling junctions (p-MTJs) allows for sufficient space to land top electrodes, eliminating the need for thick dielectric layers and CMP processes, resulting in a thinner MRAM cell with reduced manufacturing costs and improved processing compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If traditional in-plane magnetic tunneling junctions are used, then the MRAM cell structure is established, but the space for landing top electrodes is limited and thick dielectric layers are required
Solution Approach 1:
The patent transitions from in-plane magnetization to perpendicular magnetization orientation, changing the magnetic moment direction from horizontal to vertical. This dimensional change in magnetization orientation enables sufficient lateral space for top electrode landing while eliminating the need for thick dielectric layers, as the magnetic tunneling junction maintains its functionality with reduced thickness
2Area of stationary object
If thick dielectric layers are used to provide sufficient space, then space for top electrodes is adequate, but curing and CMP uniformity deteriorate
Solution Approach 1:
The patent changes the key parameter of dielectric layer thickness from thick to thin by adopting perpendicular magnetization. This parameter change provides sufficient space for top electrodes through the perpendicular magnetic tunneling junction structure while maintaining thin dielectric layer thickness, thereby ensuring proper curing and uniform chemical mechanical polishing without the defects associated with thick dielectric layers
3Area of stationary object
If perpendicular magnetic tunneling junctions are used, then space for top electrodes is sufficient and dielectric layer thickness is reduced, but manufacturing process complexity must be managed
Solution Approach 1:
The patent extracts and eliminates the need for thick dielectric layers and associated complex manufacturing steps by adopting perpendicular magnetization. The perpendicular magnetic tunneling junction structure inherently provides sufficient space for top electrodes, removing the requirement for thick dielectric layers and simplifying the manufacturing process by eliminating related curing and CMP uniformity issues
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 p-MTJ structure enables better MRAM operations with reduced manufacturing costs and improved CMP uniformity, facilitating faster switching speeds and lower switching currents.
Implementation Method 1
a magnetic tunneling junction (MTJ) disposed over a bottom electrode. A top electrode is disposed over an upper surface of the MTJ
Implementation Method 2
facilitating faster switching speeds and lower switching currents
Data Source
AI summary
A method of forming a magnetoresistive random access memory (MRAM) device including a perpendicular MTJ (magnetic tunnel junction) is provided. The method includes forming a magnetic tunneling junction (MTJ) over a bottom electrode layer. A top electrode layer is formed over an upper surface of the MTJ, and a hard mask is formed over an upper surface of the top electrode layer. A first etch is performed through the top electrode layer, through regions of the MTJ unmasked by the hard mask, to form a top electrode and an etched MTJ. Sidewall spacers are formed extending from an upper surface of the hard mask or the top electrode, along sidewalls of the top electrode and the etched MTJ, to a point below or about even with an upper surface of the bottom electrode. A resulting MRAM device structure is also provided.