Alignment Mark Placement in Semiconductor Epitaxial Fabrication
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The complexity of fabrication steps for semiconductor devices increases due to the removal of polysilicon layers stacked on alignment marks, which complicates the process.
Innovation Solution
A semiconductor device with an epitaxial layer of single-crystalline semiconductor grown on a substrate, where the alignment mark is either between the substrate and the epitaxial layer or within a recess portion, allowing the epitaxial layer to obstruct and cover the alignment mark, simplifying the fabrication process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the polysilicon layer stacked on the alignment mark is removed by etching, then the alignment mark can be used for positioning, but the fabrication steps become complicated
Solution Approach 1:
The patent extracts the alignment mark function from the polysilicon layer by creating a dedicated alignment mark structure (oxide film pattern) separate from the semiconductor layer. This allows the alignment mark to be formed independently without requiring subsequent removal of polysilicon, thus reducing fabrication complexity while maintaining alignment precision
Solution Approach 2:
The alignment mark is formed in advance during the epitaxial growth process itself, rather than being added later and then removed. The oxide film pattern is created as part of the substrate preparation before epitaxial growth, so the alignment mark is already in place and does not require additional removal steps
2Manufacturing precision
If the alignment mark is formed on the silicon substrate surface, then it can be recognized for positioning, but the epitaxial layer cannot grow uniformly over it
Solution Approach 1:
The patent applies local quality by creating an oxide film pattern with specific local properties (different from the silicon substrate) that serves as the alignment mark. This localized region has the necessary contrast for recognition while the surrounding areas maintain uniform epitaxial growth characteristics
Solution Approach 2:
The oxide film acts as an intermediary structure between the silicon substrate and the epitaxial layer. It provides the necessary contrast for alignment mark recognition while allowing the epitaxial silicon to grow uniformly over and around it, mediating between the need for visibility and uniform growth
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 approach simplifies the fabrication of alignment marks in semiconductor devices by using the epitaxial layer to obstruct and cover the alignment mark, reducing the complexity of subsequent fabrication steps.
Implementation Method 1
an epitaxial layer that includes a single-crystalline semiconductor that is epitaxially grown on a surface of the semiconductor substrate
Data Source
AI summary
Fabrication of an alignment mark in a semiconductor device is simplified. A semiconductor device including a semiconductor substrate, an epitaxial layer, and an alignment mark is provided. The epitaxial layer included in the semiconductor device includes a single-crystalline semiconductor that is epitaxially grown on a surface of the semiconductor substrate included in the semiconductor device. The alignment mark included in the semiconductor device is disposed between the semiconductor substrate and the epitaxial layer.