Carrier Etch Loading Mitigation via Mandrel Layer
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Solution Overview
Problem
The existing etch processes, such as plasma etching, often result in loading effects where holes or recesses with larger open areas are etched deeper than those with smaller open areas, leading to inconsistent dimensions and electrical properties in integrated circuits due to varying distances between adjacent structure elements.
Innovation Solution
A method involving forming structure elements with specific distances between them, depositing layers of varying thicknesses, and partially removing these layers to expose sidewalls, creating a uniform etching environment that mitigates loading effects by ensuring consistent etch rates across the integrated circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional etch processes are used, then etching can be performed on structure elements, but loading effects occur causing holes with larger open areas to be etched deeper than those with smaller open areas
Solution Approach 1:
A mandrel layer is formed between adjacent structure elements before the etch process. This mandrel layer pre-defines the etch opening area, ensuring that the etch process operates under controlled conditions regardless of the original spacing between structure elements. The mandrel layer is subsequently removed after etching, having served its purpose of standardizing the etch environment.
Solution Approach 2:
The invention changes the physical state and dimensions of the etch opening by introducing a mandrel layer with specific thickness parameters. The mandrel layer thickness is carefully selected to be between 5-50 nm, which standardizes the effective opening area during etching. This parameter control ensures uniform etch rates across different structure element spacings.
2Adaptability or versatility
If the distance between adjacent structure elements varies, then different etch rates occur, but this leads to inconsistent hole depths and compromised electrical properties
Solution Approach 1:
The mandrel layer is selectively positioned only in regions between adjacent structure elements where spacing variation occurs. This local intervention standardizes the etch opening area specifically where needed, without affecting the overall device structure. The mandrel layer's presence is localized to the inter-element spacing regions, providing uniform etching conditions precisely where spacing variations would cause problems.
3Ease of manufacture
If micro-loading or aspect ratio dependent etching occurs, then etching uniformity deteriorates, but the patent aims to achieve homogeneous etching results
Solution Approach 1:
The mandrel layer acts as an intermediary element between the structure elements and the etch process. It mediates the interaction by providing a standardized opening area that decouples the etch process from the varying spacings between structure elements. This intermediary layer absorbs the variability in spacing, allowing the etch process to proceed uniformly without direct exposure to spacing variations.
Data Source
AI summary
A method for processing a carrier may include: forming a plurality of structure elements at least one of over and in a carrier, wherein at least two adjacent structure elements of the plurality of structure elements have a first distance between each other; depositing a first layer over the plurality of structure elements having a thickness which equals the first distance between the at least two adjacent structure elements; forming at least one additional layer over the first layer, wherein the at least one additional layer covers an exposed surface of the first layer; removing a portion of the at least one additional layer to expose the first layer partially; and partially removing the first layer, wherein at least one sidewall of the at least two adjacent structure elements is partially exposed.