TMR Element Contact Fabrication via Low-Temperature Capping
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Solution Overview
Problem
Existing methods for fabricating electroconductive contacts on tunneling magnetoresistance (TMR) elements are inefficient, particularly in ensuring reliable connections without damaging the TMR elements with high temperature processes.
Innovation Solution
A method involving the deposition of a capping layer, followed by an insulator, and then a conducting material directly on the top surfaces of TMR elements, using photolithography and etching techniques to form electroconductive contacts while minimizing exposure to high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods are used to form electroconductive contacts on TMR elements, then electrical connectivity is achieved, but the TMR elements are damaged due to high temperature processes
Solution Approach 1:
A capping layer is deposited on the TMR element before forming the electroconductive contact. This preliminary protective action allows subsequent low-temperature processing to occur without damaging the TMR element, as the capping layer shields it from thermal and chemical harm during the contact formation process
Solution Approach 2:
The patent employs low-temperature deposition processes (such as sputtering or chemical vapor deposition at reduced temperatures) to form the electroconductive contact and capping layer. By changing the temperature parameter from conventional high-temperature processes to low-temperature processes, the TMR element is protected from thermal damage while still achieving reliable electrical connectivity
2Manufacturing precision
If photolithography and etching are used to form electroconductive contacts, then manufacturing precision is improved, but process complexity increases
Solution Approach 1:
The fabrication process is segmented into distinct functional steps: depositing the capping layer, depositing the insulator, photolithography patterning, etching, and finally depositing the electroconductive contact material. This segmentation allows each step to be optimized independently, achieving precise contact formation while managing overall process complexity through systematic breakdown of the fabrication sequence
Solution Approach 2:
An insulator layer is introduced as an intermediary between the capping layer and the electroconductive contact. This intermediary layer facilitates precise pattern transfer and protects underlying structures during etching, enabling manufacturing precision while the insulator itself serves as a manageable intermediate step in the overall process
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 effectively forms reliable electroconductive contacts on TMR elements without damaging them, ensuring efficient electrical connectivity while maintaining the integrity of the TMR elements.
Implementation Method 1
patterning the first photoresist using photolithography to expose portions of the insulator
Implementation Method 2
depositing a capping layer on a semiconductor device structure
Implementation Method 3
depositing an insulator on the capping layer
Data Source
AI summary
In one aspect, a method includes depositing a capping layer on a semiconductor device structure. The semiconductor device includes a plurality of tunneling magnetoresistance (TMR) elements, a corresponding one hard mask on each TMR element, a metal layer, and a plurality of electroconductive vias directly connecting the TMR elements to the metal layer. The method further includes depositing an insulator on the capping layer, depositing a first photoresist on the insulator, patterning the first photoresist using photolithography to expose portions of the insulator, etching the exposed portions of the insulator and the hard masks to expose top surfaces of the TMR elements, stripping the first photoresist, and depositing a conducting material on the top surfaces of the TMR elements to form an electroconductive contact.