Angled Surface Removal from Ferromagnetic Flux Guides
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Solution Overview
Problem
Integrated circuit fabrication processes often result in angled surfaces that detrimentally affect the performance of sensors, such as three-axis magnetic field sensors, particularly due to the formation of flux guides during the etching process.
Innovation Solution
A method involving chemical mechanical polishing (CMP) processes, specifically oxide-CMP, is used to remove angled surfaces formed on flux guides during the fabrication of magnetic field sensors, ensuring precise thickness control and improved magnetic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If integrated circuit fabrication processes are used to create flux guides, then the sensor device can be manufactured, but angled surfaces are formed that detrimentally affect sensor performance
Solution Approach 1:
The patent applies a chemical mechanical polishing (CMP) process after depositing the ferromagnetic material layer to preliminarily remove angled surfaces and create a planar surface before subsequent etching steps. This preliminary planarization prevents the angled surface defect from propagating through the fabrication process, thereby resolving the contradiction between ease of manufacture and manufacturing precision.
2Device complexity
If standard etching processes are used to form flux guides, then the fabrication process remains simple, but angled surfaces are created that harm sensor performance
Solution Approach 1:
The patent introduces a chemical mechanical polishing (CMP) process as an intermediary step between material deposition and etching. This intermediary process specifically targets and removes angled surfaces without requiring complex process changes, thereby eliminating the harmful angled surface effect while maintaining relative simplicity of the overall fabrication process.
3Productivity
If ferromagnetic material is deposited conformally on trench sidewalls, then flux guides are formed efficiently, but angled surfaces are generated at the trench opening
Solution Approach 1:
The patent extracts or removes the problematic angled surface portion from the flux guide structure using a chemical mechanical polishing (CMP) process. By selectively removing only the angled surface at the trench opening while preserving the conformally deposited ferromagnetic material on the sidewalls, the patent maintains flux guide formation efficiency while correcting the surface geometry defect.
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 CMP process effectively removes angled surfaces, enhancing the magnetic performance and functionality of the sensors by planarizing the flux guides, thereby improving the overall sensor performance.
Implementation Method 1
removing the angled surface of the circuit element using a chemical mechanical polishing process
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A method of fabricating an integrated circuit device includes forming a trench (16) in a dielectric material (14) and forming a ferromagnetic circuit element (18) having an angled surface (22) on the trench. The angled surface of the circuit element is removed using a chemical mechanical polishing (CMP) process and the trench is filled with an electrically conductive material.