Magnetoresistive Element Manufacturing via Selective Oxidation
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Solution Overview
Problem
Current methods for manufacturing magnetoresistive elements face challenges in uniformly controlling the oxidation and reduction states of magnesium oxide (MgO) and magnetic films during dry etching, leading to deteriorated electrical characteristics due to excessive hydrogen or oxygen plasma exposure, and the deliquescent nature of MgO causes further degradation in atmospheric processing.
Innovation Solution
A manufacturing method involving a two-step process in a vacuum environment, where the magnetic film and metal oxidation film are initially oxidized or reduced, followed by selective oxidation or reduction to achieve optimal states, using gases like ozone and formic acid to control the Gibbs energy change in reactions, ensuring uniform suppression of oxidation and reduction damage across the wafer surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dry etching is performed using hydrogen plasma to process magnetic films and magnesium oxide, then etching efficiency is improved, but reduction damage occurs to the magnesium oxide leading to deteriorated electrical characteristics
Solution Approach 1:
The patent converts the harmful reduction effect of hydrogen plasma on magnesium oxide into a beneficial process by intentionally reducing MgO and then recovering it through a subsequent oxidation process. The reduction damage is transformed from an unwanted side effect into a controlled intermediate step that is later reversed to improve overall device characteristics.
Solution Approach 2:
The patent changes the oxidation state parameter of magnesium oxide by performing sequential reduction and oxidation processes. The MgO is first reduced to Mg (changing oxidation state from +2 to 0), then re-oxidized back to MgO, effectively using parameter transformation to control the chemical state and eliminate damage.
2Object-affected harmful factors
If oxygen plasma is used to process magnetic films to prevent oxidation, then oxidation damage is suppressed, but excessive oxidation of the magnetic film occurs leading to deteriorated electrical characteristics
Solution Approach 1:
The patent applies partial oxidation by controlling the oxygen plasma exposure to achieve just enough oxidation to recover reduced MgO without excessive oxidation of the magnetic film. The oxidation process is carefully controlled to be sufficient for MgO recovery but limited to avoid damaging the magnetic film's electrical properties.
3Ease of manufacture
If magnesium oxide is processed in atmospheric conditions, then processing simplicity is improved, but moisture absorption occurs due to deliquescent nature causing further deterioration of electrical characteristics
Solution Approach 1:
The patent uses a vacuum environment as an inert atmosphere to prevent moisture absorption by magnesium oxide. By maintaining vacuum conditions throughout the processing sequence (reduction, oxidation, and cooling), the deliquescent MgO is protected from atmospheric moisture that would otherwise cause hydrolysis and deterioration of electrical characteristics.
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 effectively suppresses both oxidation and reduction damage to the magnetic film and magnesium oxide, maintaining optimal electrical characteristics and preventing moisture-induced deterioration, thereby ensuring consistent performance of magnetoresistive elements.
Implementation Method 1
a first step for oxidizing or reducing a magnetic film constituting the magnetoresistive element and a metal oxidation film constituting the magnetoresistive element
Implementation Method 2
the oxidized magnetic film constituting the magnetoresistive element or the oxidized metal oxidation film constituting the magnetoresistive element is selectively reduced
Implementation Method 3
in a vacuum state
Data Source
AI summary
The present invention is a manufacturing method for manufacturing a magnetoresistive element, including a first step for oxidizing or reducing a magnetic film constituting the magnetoresistive element and a metal oxidation film constituting the magnetoresistive element, and a second step performed after the first step, wherein in the second step, in a case where the magnetic film constituting the magnetoresistive element and the metal oxidation film constituting the magnetoresistive element are oxidized, the oxidized magnetic film constituting the magnetoresistive element or the oxidized metal oxidation film constituting the magnetoresistive element is selectively reduced, and in a case where the magnetic film constituting the magnetoresistive element and the metal oxidation film constituting the magnetoresistive element are reduced, the reduced magnetic film constituting the magnetoresistive element or the reduced metal oxidation film constituting the magnetoresistive element is selectively oxidized.