Seed and Bulk Layer Deposition for High Aspect Ratio Gaps
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Solution Overview
Problem
Existing methods for forming layers on substrates, particularly in semiconductor manufacturing, face challenges in achieving high-quality deposits in gaps with high aspect ratios, where the depth is significantly larger than the width, and in covering diverse surface materials effectively.
Innovation Solution
A method involving the sequential deposition of a seed layer and a bulk layer using different precursors and reactants, specifically metal and halogen atoms, with the seed layer formed through pretreatment ALD or CVD cycles and the bulk layer deposited via ALD or CVD processes, optimizing the properties of each layer to improve overall layer quality and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single precursor and reactant system is used for depositing the entire layer, then the manufacturing process is simpler, but the quality and uniformity of the deposited layer in high aspect ratio gaps deteriorates
Solution Approach 1:
The deposition process is segmented into two distinct stages: seed layer deposition using a first precursor and reactant system, followed by bulk layer deposition using a second precursor and reactant system. This segmentation allows optimization of each stage for its specific purpose, with the seed layer providing nucleation sites and the bulk layer providing material fill, thereby resolving the contradiction between process simplicity and layer quality in high aspect ratio gaps
Solution Approach 2:
The seed layer is deposited as a preliminary action before bulk layer deposition. This preliminary seed layer provides essential nucleation sites and surface preparation that enable subsequent bulk material to deposit uniformly deep within high aspect ratio gaps, achieving manufacturing precision that would not be possible with a single deposition step
2Stability of the object's composition
If the same precursor is used for both seed layer and bulk layer, then the process is more consistent, but the ability to optimize properties of each layer is reduced
Solution Approach 1:
Different precursors are used for different layers to provide local quality optimization: the first precursor is selected with properties optimized for seed layer formation (nucleation capability, surface reactivity), while the second precursor is selected with properties optimized for bulk layer deposition (material properties, deposition rate). This local quality differentiation resolves the contradiction between process consistency and layer property optimization
Solution Approach 2:
The final structure is a composite of two differently deposited layers: the seed layer with properties optimized for nucleation and adhesion, and the bulk layer with properties optimized for material performance. This composite approach allows each layer to have tailored properties while maintaining overall process consistency through systematic deposition procedures
3Productivity
If conventional ALD or CVD is used without seed layer pretreatment, then the deposition is faster, but the adhesion to diverse surface materials and uniformity in high aspect ratio gaps deteriorates
Solution Approach 1:
A preliminary seed layer deposition step is introduced before bulk layer deposition. This preliminary action prepares the surface by creating a uniform nucleation layer that ensures subsequent bulk material adheres reliably and deposits uniformly throughout high aspect ratio gaps, resolving the contradiction between deposition speed and adhesion/uniformity
Solution Approach 2:
The seed layer acts as an intermediary between the diverse substrate surface materials and the bulk layer material. It provides a standardized interface that improves adhesion and ensures uniform deposition of the bulk layer, even in challenging high aspect ratio gap geometries, thereby resolving the contradiction between productivity and reliability
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 the formation of high-quality, uniform metal layers that effectively fill gaps with high aspect ratios and adhere well to diverse surface materials, enhancing the electrical properties and step coverage of the deposited films, such as achieving low resistivity and uniform molybdenum films.
Implementation Method 1
depositing a seed layer on the substrate... supplying a first precursor comprising metal and halogen atoms to the substrate; and supplying a first reactant to the substrate, wherein a portion of the first precursor and the first reactant react to form at least a portion of the seed layer
Implementation Method 2
the substrate is exposed to a pulse of the first precursor and a monolayer of the first precursor may be chemisorbed on the surface of the substrate
Implementation Method 3
depositing a bulk layer on the seed layer... supplying a second precursor comprising metal and halogen atoms to the seed layer; and, supplying a second reactant to the seed layer, wherein a portion of the second precursor and the second reactant react to form at least a portion of the bulk layer on the seed layer
Data Source
AI summary
There is provided a method of forming a layer, comprising depositing a seed layer on the substrate; and depositing a bulk layer on the seed layer. Depositing the seed layer comprises supplying a first precursor comprising metal and halogen atoms to the substrate; and supplying a first reactant to the substrate. Depositing the bulk layer comprises supplying a second precursor comprising metal and halogen atoms to the seed layer; and, supplying a second reactant to the seed layer.