Magnetoresistive Element Manufacturing Temperature Control
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Solution Overview
Problem
The magnetoresistive effect elements, particularly TMR elements used in MRAMs, have an MR ratio that is not high enough, necessitating a manufacturing method that enhances this ratio beyond conventional structures.
Innovation Solution
A manufacturing method involving the formation of a tunnel barrier layer on a substrate, followed by cooling the substrate before forming either the magnetization free layer or the fixed layer, and then raising the substrate temperature after forming these layers to prevent dew condensation and improve yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional manufacturing methods are used to form the tunnel barrier layer and magnetic layers, then the production process is simple, but the MR ratio is not high enough
Solution Approach 1:
The patent applies parameter changes by controlling substrate temperature during the manufacturing process. Specifically, the substrate is cooled to below room temperature during tunnel barrier layer formation, then heated to room temperature or higher before forming the magnetic layers. This temperature parameter control improves the MR ratio by optimizing the tunnel barrier properties without fundamentally changing the manufacturing process structure.
Solution Approach 2:
The patent implements preliminary action by cooling the substrate before forming the tunnel barrier layer. This preliminary cooling step prepares the substrate in an optimal state for tunnel barrier formation, which subsequently leads to higher MR ratio. The cooling is performed in advance of the critical tunnel barrier formation process to ensure optimal conditions.
2Manufacturing precision
If the substrate is cooled after forming the tunnel barrier layer to improve MR ratio, then the magnetic characteristics are enhanced, but dew condensation may occur on the substrate
Solution Approach 1:
The patent applies preliminary action by heating the substrate to room temperature or higher before forming the magnetic layers. This preliminary heating prevents dew condensation from occurring when the substrate is subsequently cooled or exposed to ambient conditions, eliminating the harmful effect while maintaining the benefits of prior cooling for MR ratio enhancement.
Solution Approach 2:
The patent implements periodic action through temperature cycling: cooling the substrate below room temperature during tunnel barrier formation, then heating it to room temperature or higher before magnetic layer formation. This periodic temperature variation optimizes different process stages - cooling for barrier quality and heating for preventing condensation - thereby resolving the contradiction between magnetic characteristics and dew condensation prevention.
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 achieves a higher MR ratio for magnetoresistive effect elements while preventing dew condensation and enhancing the magnetic characteristics, thus improving the performance and reliability of MRAM devices.
Implementation Method 1
a second step of cooling the substrate after the first step
Implementation Method 2
a fourth step of raising a temperature of the substrate after the third step
Data Source
AI summary
This invention provides a manufacturing method of a magnetoresistive effect element having a higher MR ratio than a conventional element. A manufacturing method of a magnetoresistive effect element of an embodiment of the invention includes: a step of forming a tunnel barrier layer on a substrate, on a surface of which one of a magnetization free layer and a magnetization fixed layer is formed; a step of cooling the substrate after the step of forming a tunnel barrier layer; a step of forming an other one of the magnetization free layer and the magnetization fixed layer on the tunnel barrier layer after the step of cooling; and a step of raising a temperature of the substrate after the step of forming the other one of the magnetization free layer and the magnetization fixed layer.