Unstable Metal Nitride Adhesion for Copper Semiconductor Structures
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Solution Overview
Problem
In integrated circuit fabrication, incompatible materials often require special deposition techniques or adhesion layers to adhere, and forming small electrical conductors like copper buried in other materials is difficult and costly due to the complexity of process steps.
Innovation Solution
The method involves depositing an unstable metal nitride layer using ALD or CVD, followed by thermal or non-thermal decomposition to form a pure metal layer, which acts as an adhesion layer and allows for the deposition of consecutive layers in a single step, using a nitrided barrier layer to prevent nitrogen formation and enable precise patterning and adhesion on substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If incompatible materials are deposited directly onto each other, then the fabrication process is simplified, but adhesion is insufficient and delamination occurs
Solution Approach 1:
An unstable metal nitride layer is deposited between incompatible materials (e.g., copper and silicon dioxide) to serve as an intermediary adhesion layer. This nitride layer decomposes thermally to form a transition structure that bonds both materials, eliminating the need for separate adhesion layers while preventing delamination.
Solution Approach 2:
The unstable metal nitride layer undergoes parameter change through thermal decomposition. By controlling temperature and time parameters, the nitride transforms from a stable deposited state to a decomposed state that provides both adhesion and compatibility with adjacent layers, resolving the adhesion issue without adding process complexity.
2Reliability
If conventional methods are used to form buried copper conductors, then adhesion can be achieved, but the number of process steps increases and cost effectiveness decreases
Solution Approach 1:
The deposition and adhesion formation steps are merged into a single process. The unstable metal nitride is deposited and then thermally decomposed in situ to form the adhesion structure, combining what would traditionally require separate adhesion layer deposition and bonding steps into one integrated process sequence.
Solution Approach 2:
The unstable metal nitride layer serves dual functions: it acts as both the adhesion layer and the precursor for the final metal structure. Through self-service, the same material provides both the bonding interface and the conductive path, eliminating the need for separate adhesion layers and reducing process steps.
3Reliability
If small conductors like nanowires are deposited using conventional techniques, then adhesion may be achieved, but deposition difficulty and cost increase significantly
Solution Approach 1:
For nanowire and small conductor deposition, the unstable metal nitride is deposited at controlled parameters and then thermally decomposed to form the final structure. This parameter-controlled transformation enables precise deposition of small-scale conductors with adequate adhesion while maintaining ease of manufacture through a standardized thermal processing step.
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 ensures adequate adhesion and conductivity of copper or nickel layers with reduced process complexity, enabling precise deposition and patterning of nanowires and conductive lines with improved adhesion and low reflectivity for further processing.
Implementation Method 1
the material 14 may then be converted to another material incompatible with the material 12 if directly deposited on the material 12. By depositing the material 14 in a first form and then converting it into a second form
Implementation Method 2
The material 14, in one embodiment, may be an unstable metal nitride, such as Cu3N or Cu4N, as two examples. In one embodiment, the material 14 is deposited by a atomic layer deposition (ALD) and/or chemical vapor deposition (CVD)
Data Source
AI summary
Incompatible materials, such as copper and nitrided barrier layers, may be adhered more effectively to one another. In one embodiment, a precursor of copper is deposited on the nitrided barrier. The precursor is then converted, through the application of energy, to copper which could not have been as effectively adhered to the barrier in the first place.