Sacrificial Layer Patterning for Aligned MIM Capacitor Fabrication
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Solution Overview
Problem
The complexity and cost of manufacturing micro- and nano-electronic devices, particularly MIM type capacitances, are increased due to the multiplication and complexity of photolithography and etching processes, leading to inefficiencies and misalignment of material layers.
Innovation Solution
A method using a sacrificial layer made of lithiated materials like lithium oxide or lithium oxynitride, which inhibits the growth of functional layers, allowing selective deposition and structuring through atomic layer deposition and plasma etching, reducing the number of manufacturing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography and etching processes are used to structure material layers, then manufacturing precision can be achieved, but device complexity and manufacturing cost increase due to multiple exposure and self-aligned multi-structuring steps
Solution Approach 1:
The patent extracts the structuring function from complex photolithography-etching sequences and concentrates it into a single atomic layer deposition step using a sacrificial layer. The sacrificial layer is deposited once, then selectively removed to create the desired pattern, eliminating the need for multiple lithography exposures and etching steps while maintaining alignment precision.
Solution Approach 2:
The sacrificial layer is deposited in advance before the functional layers. This preliminary action defines the future structure pattern, allowing subsequent functional layers to be deposited conformally without requiring complex in-situ patterning steps. The sacrificial layer serves as a pre-established template that guides the entire manufacturing process.
2Manufacturing precision
If multiple photolithography and etching steps are implemented, then structuring capability is improved, but manufacturing time and production cost increase
Solution Approach 1:
The patent merges multiple separate lithography and etching operations into a single atomic layer deposition step followed by selective sacrificial layer removal. This consolidation reduces the total number of process steps, decreases manufacturing time, and improves productivity while maintaining the ability to create complex structured patterns.
Solution Approach 2:
The sacrificial layer acts as an intermediary that enables complex structuring without requiring complex processes. It mediates between the simple conformal deposition process and the desired complex final structure, allowing the functional layers to be deposited in a single step while the sacrificial layer is subsequently removed to reveal the patterned structure.
3Stability of the object's composition
If conformal deposition is performed over the entire surface, then layer continuity is maintained, but selective structuring requires additional photolithography and etching steps
Solution Approach 1:
The patent applies local quality by creating spatial variation in the sacrificial layer distribution. The sacrificial layer is present in some regions and absent in others, creating locally different deposition conditions. This allows conformal deposition to proceed uniformly across the entire surface while the sacrificial layer's local presence or absence determines where functional layers are ultimately formed, achieving both continuity and selectivity.
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 efficient and cost-effective structuring of functional layers with reduced misalignment, lowering the number of manufacturing steps and maintaining high purity and conformability of layers, thus improving the efficiency and cost-effectiveness of micro- and nano-electronic device production.
Implementation Method 1
an interaction between the compounds present in the sacrificial layer and these precursors takes place, then leading to a delay or even an absence of growth of the first atomic layers of the functional layer
Implementation Method 2
The sacrificial layer is then removed, in particular by means of a plasma etching process
Data Source
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AI summary
The invention relates, firstly, to a method for structuring a functional layer (130), comprising at least the following steps: a) providing a substrate (110) having a surface locally covered by a so-called sacrificial layer (120), one or more areas of the surface of the substrate (110) being devoid of the sacrificial layer (120); b) selectively growing the functional layer (130) on the area(s) of the surface of the substrate (110) devoid of the sacrificial layer (120); c) removing the sacrificial layer (120); thereby the surface of the substrate (110) is covered by a structured functional layer (130). The invention further relates to a method for preparing a MIM-type capacitance, by implementing the structuring method to structure at least one layer of the capacitance.Applications: micro- and nano-electronic devices such as electronic chips, manufacturing of high-density MIM-type capacitances.