Semiconductor Nanowire CMP Exposure via Layer Segmentation
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Solution Overview
Problem
Existing methods for manufacturing semiconductor devices with nano wires struggle to accurately expose the upper side of nano wires during chemical-mechanical polishing due to their small lateral dimensions and opaque material layers, leading to inaccuracy and potential damage to the nano wire structure.
Innovation Solution
A method is introduced where a further layer with a thickness smaller than the nano wire is deposited, increasing its visibility by altering its lateral dimensions and using materials with different refractive indices or a strongly reflecting layer to enhance detection, allowing for accurate exposure of the nano wire during CMP, potentially using optical systems or pattern recognition techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a layer is deposited over the semiconductor body with the nano wire, then the nano wire is protected during subsequent processing, but the upper side of the nano wire cannot be accurately exposed during CMP due to small lateral dimensions and opaque material
Solution Approach 1:
The deposited layer is segmented into two distinct parts: a first layer with larger thickness that provides protection and enhances visibility, and a second layer with smaller thickness that allows accurate exposure of the nano wire upper side during CMP. This segmentation resolves the contradiction by assigning different functional thicknesses to different regions of the deposited layer.
Solution Approach 2:
Different regions of the deposited layer are given different local qualities in terms of thickness. The first layer has a larger thickness suitable for protection and visibility enhancement, while the second layer has a smaller thickness optimized for accurate nano wire exposure. This local differentiation allows simultaneous achievement of protection and precision exposure.
2Difficulty of detecting and measuring
If the lateral dimensions of the nano wire are increased to improve visibility, then the nano wire becomes easier to detect, but the component density and miniaturization goals are compromised
Solution Approach 1:
A deposited layer acts as an intermediary substance that enhances the visibility of the nano wire without requiring changes to the nano wire's actual dimensions. The layer with different refractive index or strongly reflecting material properties amplifies the optical contrast, making the nano wire detectable while maintaining its original small lateral dimensions for high density.
Solution Approach 2:
The deposited layer introduces optical property changes (analogous to color changes) by utilizing materials with different refractive indices or strongly reflecting properties. This creates enhanced optical contrast that improves nano wire visibility and detectability during CMP without altering the physical dimensions of the nano wire itself.
3Measurement precision
If a strongly reflecting layer or layer with different refractive index is deposited, then the transition between layers becomes more visible for detection, but the device structure becomes more complex
Solution Approach 1:
The deposited layer serves multiple functions simultaneously: it protects the nano wire during processing, enhances visibility through optical contrast, enables accurate transition detection during CMP, and can be integrated with subsequent device structures. This multi-functionality reduces the need for additional separate layers or structures.
Solution Approach 2:
The solution utilizes composite material properties by depositing a layer that combines protective characteristics with enhanced optical properties (different refractive index or strong reflectivity). This composite approach allows a single layer to provide both mechanical protection and optical enhancement, reducing overall structural complexity.
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 enables precise exposure of the nano wire, reducing inaccuracies in the CMP process and allowing for the formation of functional semiconductor elements like transistors with improved visibility and electrical functionality.
Implementation Method 1
The difference in refractive index between the layer and the further layer contributes to a better visibility of the transition between the further layer and the layer
Implementation Method 2
using materials with different refractive indices or a strongly reflecting layer to enhance detection
Data Source
Figure 1a~2b
Figure 3a~5b
Figure 6~7
AI summary
The invention relates to a method of manufacturing a semiconductor device (10) with a substrate (11) and a semiconductor body (1), whereby in the semiconductor body (1) a semiconductor element is formed by means of a mesa- shaped protrusion of the semiconductor body (1), which is formed on the surface of the semiconductor device (10) as a nano wire (2), whereupon a layer (3) of a material is deposited over the semiconductor body (1) and the resulting structure is subsequently planarized in a chemical-mechanical polishing process such that an upper side of the nano wire (3) becomes exposed. According to the invention, a further layer (4) of a further material is deposited over the semiconductor body with the nano wire (2) before the layer (3) of the material is deposited, which further layer (4) is given a thickness smaller than the height of the nano wire (2), and a material is chosen for the further material such that, viewed in projection, the transition between the layer (3) and the further layer (4) is discernible before the nano wire (2) is reached. In this way the nano wire (2) can be exposed more accurately in the device (10). This increases the yield of useful devices (10).