Integrated Chip Inductor Magnetic Structure for Residue-Free Etching
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Solution Overview
Problem
Inductors in integrated circuits consume a large area and the residue from the magnetic structure, such as cobalt oxygen (CoO) precipitates, negatively impact the effectiveness of magnetic fields by causing leakage and reducing the reliability of the inductor structure.
Innovation Solution
Incorporating a first pattern enhancement layer between the magnetic structure and the etch stop layer, which is thicker and has a faster etch rate than the magnetic structure layers, to delay exposure of the etch stop layer during wet etching, allowing complete removal of OCZT residue before it contacts the etch stop layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a magnetic structure is formed over an etch stop layer during inductor fabrication, then the magnetic structure can concentrate magnetic flux near conductive wires, but residue from the magnetic structure (such as CoO precipitates) adheres to the etch stop layer causing magnetic field leakage and reducing reliability
Solution Approach 1:
A pattern enhancement layer is introduced as an intermediary between the magnetic structure and the etch stop layer. This intermediate layer serves as a barrier that prevents residue (CoO precipitates) from the magnetic structure from adhering to the etch stop layer, thereby eliminating the source of magnetic field leakage while maintaining the magnetic concentration function of the magnetic structure.
Solution Approach 2:
The pattern enhancement layer is formed in advance before the magnetic structure is deposited. This preliminary action creates a protective barrier on the etch stop layer surface, ensuring that when the magnetic structure is later formed and etched, any residue generated during the process cannot contaminate the etch stop layer, thus preventing future magnetic field leakage issues.
2Manufacturing precision
If the etch stop layer is exposed during wet etching of the magnetic structure, then the magnetic structure can be patterned, but residue contacts the etch stop layer causing harmful effects
Solution Approach 1:
The pattern enhancement layer acts as a mediator between the wet etching process and the etch stop layer. It allows the etching process to proceed and pattern the magnetic structure effectively, while simultaneously serving as a protective barrier that prevents residue from contacting the etch stop layer, thus eliminating harmful effects without compromising manufacturing precision.
3Ease of manufacture
If OCZT residue is not completely removed before contacting the etch stop layer, then manufacturing process can be simplified, but magnetic field leakage occurs reducing inductor performance
Solution Approach 1:
Instead of trying to completely remove OCZT residue through complex additional cleaning steps, the pattern enhancement layer is used to convert the harmful residue into a non-harmful situation. The residue can remain in the pattern enhancement layer without affecting the etch stop layer or causing magnetic field leakage, thus maintaining manufacturing simplicity while ensuring magnetic structure effectiveness.
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 solution effectively prevents OCZT residue from adhering to the etch stop layer, enhancing the reliability of the magnetic structure in concentrating magnetic flux near the conductive wires, thereby improving the inductor's performance and reducing manufacturing inefficiencies.
Implementation Method 1
the first pattern enhancement layer, which is thicker and has a faster etch rate than the magnetic structure layers, to delay exposure of the etch stop layer during wet etching
Implementation Method 2
a first conductive wire and a second conductive wire extending in parallel over the magnetic structure, wherein the magnetic structure is configured to modify magnetic field generated by the first conductive wire and the second conductive wire
Data Source
AI summary
The present disclosure relates to, in part, an inductor structure that includes an etch stop layer arranged over an interconnect structure overlying a substrate. A magnetic structure includes a plurality of stacked layers is arranged over the etch stop layer. The magnetic structure includes a bottommost layer that is wider than a topmost layer. A first conductive wire and a second conductive wire extend in parallel over the magnetic structure. The magnetic structure is configured to modify magnetic fields generated by the first and second conductive wires. A pattern enhancement layer is arranged between the bottommost layer of the magnetic structure and the etch stop layer. The pattern enhancement layer has a first thickness, and the bottommost layer of the magnetic structure has a second thickness that is less than the first thickness.