Shallow Trench Isolation Dishing Prevention via Hard Mask Removal
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Solution Overview
Problem
Conventional shallow trench isolation (STI) manufacturing methods face limitations due to the dishing phenomenon and height constraints imposed by the hard mask layer, leading to suboptimal electrical isolation and flexibility in semiconductor device manufacturing.
Innovation Solution
The method involves forming trenches in a substrate with a hard mask layer, removing it, and then filling the trenches with an insulating material, allowing for planarization without the hard mask layer's height constraints, thus preventing dishing and enhancing flexibility in component application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the hard mask layer is kept during the planarization process, then the STI height is constrained by the hard mask layer height, but this prevents flexible adjustment of STI height for different component applications
Solution Approach 1:
The process is segmented into distinct stages: first forming the trench with the hard mask layer present, then removing the hard mask layer, and finally filling the trench. This segmentation allows the STI height to be independently controlled without being constrained by the hard mask layer height, thereby achieving flexibility in STI height adjustment while maintaining manufacturing precision.
Solution Approach 2:
The hard mask layer is removed before the trench filling process. This preliminary action eliminates the height constraint that would otherwise be imposed by the hard mask layer, allowing the subsequent filling process to create STI structures with any desired height without being limited by the original hard mask layer thickness.
2Productivity
If planarization is performed on large area STI, then the etching rate varies between central and periphery regions, but this causes dishing phenomenon that degrades STI quality
Solution Approach 1:
The hard mask layer is removed before performing the planarization process on the filled trench. This preliminary removal eliminates the differential etching issue that occurs when planarizing over the hard mask layer, as the planarization now acts only on the filler material, ensuring uniform flatness across the entire STI area without dishing phenomenon.
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 prevents the dishing phenomenon and allows for greater flexibility in STI height, improving the quality and reliability of electrical isolation in semiconductor devices.
Implementation Method 1
an etching process is then carried out to form a trench 20 in the substrate
Implementation Method 2
a deposition process, such as a chemical vapor deposition (CVD), is performed to form a filler 24 in the trench 20
Implementation Method 3
a planarization process such as chemical mechanical polishing (CMP) is then carried out
Data Source
AI summary
A manufacturing method for a shallow trench isolation. First, a substrate is provided, a hard mask layer and a patterned photoresist layer are sequentially formed on the substrate, at least one trench is then formed in the substrate through an etching process, the hard mask layer is removed. Afterwards, a filler is formed at least in the trench and a planarization process is then performed on the filler. Since the planarization process is performed only on the filler, so the dishing phenomenon can effectively be avoided.