Cladded Conductive Lines in Magnetic Memories
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Solution Overview
Problem
Existing magnetic memory devices face errors due to non-uniform magnetization states in cladding materials, which can lead to programming errors and unintended switching, caused by process irregularities and external magnetic fields.
Innovation Solution
A method of forming a magnetoelectronic device with a dielectric material surrounding a magnetic bit, etching to define an opening without exposing the bit, depositing a blanket cladding layer, and removing it at the bottom using sputtering to prevent protrusions, followed by forming a conductive bit line and capping with cladding material, with tapered ends to prevent magnetic reversal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bit top electrode extends above the surrounding dielectric material to provide electrical contact, then electrical connectivity is achieved, but a bump occurs in the cladding material causing non-uniform magnetization state
Solution Approach 1:
The patent applies preliminary action by performing the etch stop function before cladding deposition. The etch stop layer is deposited and patterned to define contact holes, ensuring that the bit top electrode can be accessed without exposing the magnetic bit during subsequent etching steps. This preliminary structuring prevents the formation of bumps in the cladding material by controlling the etching depth and preventing over-etching that would expose the bit electrode.
2Use of energy by moving object
If cladding material is deposited to reduce write current, then power consumption decreases, but magnetic field reversal may occur in cladding locations due to strong external fields
Solution Approach 1:
The patent applies local quality by creating non-uniform cladding structures with varying thickness in different regions. The cladding material is deposited to form thicker regions in areas more susceptible to external magnetic fields, providing enhanced protection against field reversal. The etch stop layer is strategically positioned to control cladding thickness locally, ensuring that critical regions have sufficient cladding material to maintain magnetic stability while still achieving overall current reduction.
3Ease of manufacture
If the etch process is used to provide electrical contact to the bit, then connectivity is achieved, but the bit top electrode may protrude causing defects in the cladding layer
Solution Approach 1:
The patent introduces an etch stop layer as an intermediary between the bit top electrode and the cladding material. This intermediate layer controls the etching process by stopping at a predetermined depth, preventing the etch from exposing the bit top electrode. The etch stop layer acts as a mediator that allows electrical contact formation through controlled etching while simultaneously preventing protrusion defects in the subsequent cladding layer by maintaining proper depth control.
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 errors by minimizing defects in cladding layers and preventing magnetic reversal, resulting in improved programming accuracy and reduced failures under external magnetic fields.
Implementation Method 1
removing by a sputtering process the blanket layer in the bottom of the opening and the dielectric over the magnetic bit
Data Source
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AI summary
A method of forming a magnetoelectronic device includes forming a dielectric material surrounding a magnetic bit, etching the dielectric material defining an opening over the magnetic bit without exposing the magnetic bit, the opening having a sidewall, depositing a blanket layer of cladding material over the dielectric material, including over the sidewall, removing by a sputtering process the blanket layer in the bottom of the opening and the dielectric matepal over the magnetic bit, and forming a conductive matepal within the opening to form a bit line. This process reduces errors caused by process irregularities such as edges of the bits protruding and thereby causing defects in the cladding layer formed thereover. A bit line or digit line so formed may optionally be tapered at the ends to prevent magnetic reversal of the bit line magnetic moment that otherwise may occur due to external magnetic fields.