Networked Blocking Layer for Selective ALD Deposition
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Solution Overview
Problem
The semiconductor industry faces challenges in selective deposition, particularly in blocking SiO2 surfaces, as existing methods lose selectivity due to poor packing of non-polar tail groups, leading to nucleation of ALD process reactants and products, which results in loss of selectivity.
Innovation Solution
A method involving the use of blocking molecules with a general formula A-L-Z, where A is a reactive head group, L is a linking group, and Z is a reactive tail group, exposed to a polymer initiator to form a networked blocking layer on a substrate, inhibiting deposition on one surface relative to another, using specific compounds like ((CH3)2N)3SiC6H12COOH with ethylene diamine or AIBN for cross-linking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blocking molecules with non-polar tail groups are used to block SiO2 surfaces, then selective deposition is initially achieved, but the blocking layer loses selectivity after a few ALD cycles due to poor packing of tail groups
Solution Approach 1:
The patent changes the chemical state of the blocking layer by introducing cross-linkable functional groups (epoxy, vinyl, or isocyanate groups) that react with diamine crosslinking agents. This transforms the blocking layer from a simple physisorbed monolayer to a chemically cross-linked network, fundamentally altering its stability parameters and preventing tail group disorganization that leads to selectivity loss.
Solution Approach 2:
The patent creates a composite blocking layer structure consisting of the initial blocking molecules (with head groups that bind to SiO2) cross-linked with diamine agents. This composite structure combines the surface-binding capability of the blocking molecules with the network-forming capability of the cross-linker, producing a more stable and durable blocking layer.
2Ease of manufacture
If simple blocking layers are used, then the process is simple and fast, but nucleation of ALD reactants occurs due to poor packing of tail groups
Solution Approach 1:
The patent performs a preliminary cross-linking step before the main ALD deposition process. The blocking layer is exposed to diamine vapor or solution, allowing cross-linking to occur in advance. This preliminary action creates a stable, densely packed blocking structure that prevents subsequent nucleation issues during ALD processing, while adding only minimal process steps.
3Reliability
If cross-linking is implemented to improve blocking stability, then selectivity is maintained, but additional process steps and chemicals are required
Solution Approach 1:
The patent employs self-assembled monolayers (SAMs) as the blocking molecules, which automatically organize and bind to SiO2 surfaces without requiring complex deposition equipment. The cross-linking process uses vapor-phase or solution-phase diamine exposure, allowing the system to self-organize into a cross-linked network without complex process control, thereby maintaining simplicity while achieving enhanced stability.
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
The networked blocking layer effectively prevents deposition on the first surface, maintaining selectivity and allowing deposition on the second surface, enhancing the semiconductor industry's ability to bypass costly lithographic steps in device miniaturization.
Implementation Method 1
selective deposition of a film using self-assembled monolayers
Implementation Method 2
cross link the tail groups to form a dense network of the blocking molecules
Data Source
AI summary
Methods of depositing a film selectively onto a first substrate surface relative to a second substrate surface are described. The methods include exposing a substrate to a blocking molecule to selectively deposit a blocking layer on the first surface. The blocking layer is exposed to a polymer initiator to form a networked blocking layer. A layer is selectively formed on the second surface. The blocking layer inhibits deposition on the first surface. The networked layer may then optionally be removed.