Semiconductor Metal-Layer Laser Marking via Oxidation Contrast
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Solution Overview
Problem
Existing laser marking methods struggle to provide recognizable marks on metal layers containing high-melting-point metals, especially when the metal layer is thick, as etching is difficult and fails to expose underlying foundation layers.
Innovation Solution
A semiconductor device and laser marking method that involves pulse radiating a laser beam to create a metal layer with an outline portion and a central portion, utilizing oxidation differences to achieve visible marks by increasing the degree of oxidation in the outline portion and decreasing it in the central portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a laser beam is radiated to etch a thick metal layer containing high-melting-point metal, then the foundation layer can be exposed, but the etching process becomes impossible or ineffective
Solution Approach 1:
The patent changes the mechanism from physical etching to chemical oxidation by controlling laser irradiation parameters. By adjusting laser power, pulse duration, and scanning speed, the metal surface undergoes oxidation to form colored oxide layers, enabling mark formation without requiring etching through the entire metal layer thickness.
Solution Approach 2:
The laser beam acts as a strong oxidizing agent, directly oxidizing the metal surface to form colored oxide marks. This accelerated oxidation process occurs rapidly under laser irradiation, creating visible contrast marks without needing to remove material through etching.
2Device complexity
If conventional laser marking is used on thick high-melting-point metal layers, then the process remains simple, but the marks become unrecognizable
Solution Approach 1:
The patent utilizes color changes in metal oxides formed by laser irradiation. Different oxidation states produce different colors (e.g., black, brown, blue), creating highly visible contrast marks on the metal surface. This color-based marking mechanism works effectively on thick high-melting-point metal layers where etching fails.
3Strength
If the metal layer thickness is increased for better electrical performance, then the electrical properties improve, but the ability to etch through to the foundation layer is lost
Solution Approach 1:
The patent transitions from thickness-dependent etching to surface-only oxidation by changing the laser processing parameters. The oxidation process only affects the surface layer, creating visible marks without requiring penetration through the entire metal layer, thus preserving both electrical performance and marking capability.
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 creation of recognizable laser marks on metal layers with high melting points by altering the oxidation state, allowing for clear identification even when etching is challenging.
Implementation Method 1
the first action increasing a degree of oxidization of the outline portion defining an outline of the mark
Implementation Method 2
the second action decreasing a degree of oxidization of the central portion of the mark located inward of the outline portion
Data Source
AI summary
A semiconductor device that is a facedown mountable, chip-size-package type semiconductor device, the semiconductor device including: a semiconductor substrate; and a metal layer that is disposed on the semiconductor substrate and is exposed to outside. One or more marks are provided on an exposed surface of the metal layer. The one or more marks each include an outline portion defining an outline of the mark, and a central portion located inward of the outline portion. In a plan view of the exposed surface of the metal layer, the outline portion has a color different from at least one of a color of the central portion or a color of a base portion that is a portion of the exposed surface of the metal layer on which the one or more marks are not provided.