Thin-Film Magnetic Head Identification Mark Visibility Under Opaque Layers
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Solution Overview
Problem
In the thin-film wafer process for manufacturing magnetic heads, identification marks or targets formed on the wafer are obscured by opaque films, making it impossible to use them as references in downstream processes, as they can only be seen through transparent films before the protection film is formed.
Innovation Solution
A method involving forming a predetermined pattern or elements on a substrate, followed by a transparent film, then a pattern-transferred film using a photosensitive material, and finally an opaque film, allowing the targets and addresses to be visible even under the opaque layer by creating three-dimensional shapes that correspond to the original patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an opaque film is formed on or above identification marks or targets, then the film structure is complete and downstream processes can proceed, but the identification marks or targets become invisible and cannot be used as references in downstream processes
Solution Approach 1:
The patent creates three-dimensional protrusions at the identification mark positions on the opaque film surface. By transitioning from two-dimensional flat marks to three-dimensional protrusions, the marks become visible from the top side of the opaque film, allowing downstream processes to detect and use them as references without requiring the film to be transparent.
Solution Approach 2:
The patent forms the identification marks or targets at specific positions before forming the opaque film. This preliminary positioning allows the marks to serve as references for subsequent processes, and the marks are designed to protrude through the opaque film so they remain accessible and visible for alignment and identification in downstream steps.
2Difficulty of detecting and measuring
If identification marks are formed on the protection film (uppermost layer), then the marks are visible and can be referred after completing the wafer, but the marks cannot be utilized in upstream processes executed before the protection film forming process
Solution Approach 1:
The patent forms identification marks or targets at specific positions on the substrate or on films formed in upstream processes, before the protection film is deposited. This allows the marks to be established early in the process sequence and used for alignment and identification in subsequent upstream processes, eliminating the need to wait until the protection film is formed.
Solution Approach 2:
The patent uses the identification marks as intermediary reference elements that persist through multiple process stages. These marks serve as stable references that can be detected and used for alignment in upstream processes, and their positions are maintained through the formation of subsequent films, allowing them to continue serving as references through the entire process sequence.
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
Enables the use of targets and addresses as references even after an opaque film is applied, preventing displacement and simplifying the transfer process, while maintaining clarity and precision of the pattern edges.
Implementation Method 1
a step of forming a pattern-transferred film having shapes corresponding to shapes of the formed predetermined pattern film or predetermined elements, on the formed transparent film
Data Source
AI summary
A processing method of a thin-film includes a step of forming a predetermined pattern film or predetermined elements on a substrate or on a film formed in an upstream process, a step of forming a transparent film over the formed predetermined pattern film or predetermined elements, a step of forming a pattern-transferred film having shapes corresponding to shapes of the formed predetermined pattern film or predetermined elements, on the formed transparent film, and a step of forming an opaque film on the pattern-transferred film.