Silver Alloy Interconnects for Narrow Gaps
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Solution Overview
Problem
Current conductive interconnect materials in semiconductor devices face issues such as corrosion, poor resistance to electromigration, and difficulty in forming narrow gaps due to adhesion and agglomeration problems, particularly with aluminum and copper, and challenges in depositing silver in narrow openings.
Innovation Solution
The use of silver or silver alloys with specific liner materials and annealing processes to form conductive elements, allowing for the filling of narrow openings and improving adhesion, thereby reducing agglomeration and enhancing conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If aluminum is used as interconnect material, then adhesion to dielectric materials is improved, but resistance to electromigration and corrosion deteriorates
Solution Approach 1:
The patent uses composite interconnect structures combining copper core with aluminum or aluminum alloy layers. The copper provides excellent electromigration resistance and conductivity, while the aluminum outer layer provides good adhesion to dielectric materials and compatibility with existing CMOS processes. This composite approach resolves the contradiction by leveraging the strengths of each material.
Solution Approach 2:
The aluminum-containing layer serves multiple functions: it adheres to dielectric materials, provides a diffusion barrier, and maintains compatibility with standard semiconductor manufacturing processes. This multi-functionality allows the structure to achieve both good adhesion and reliability without requiring entirely new materials.
2Use of energy by moving object
If copper is used to form conductive interconnects, then conductivity is improved, but adhesion to dielectric materials and self-adhesion deteriorates
Solution Approach 1:
The patent employs composite structures where copper is combined with aluminum or aluminum alloys. The copper core maintains high conductivity, while the aluminum-containing outer layer provides the necessary adhesion to dielectric materials and self-adhesion properties, enabling ease of manufacture.
Solution Approach 2:
The aluminum-containing layer acts as an intermediary between the copper core and the dielectric material. It provides the adhesion interface that copper lacks, while allowing the copper to maintain its superior conductivity properties in the core region.
3Use of energy by moving object
If silver is used to form conductive interconnects, then resistivity is reduced, but ability to fill narrow gaps deteriorates
Solution Approach 1:
The patent combines silver with aluminum or aluminum alloys to create composite interconnect materials. The silver content provides low resistivity, while the aluminum component improves wetting and filling characteristics in narrow gaps, enabling manufacturing precision.
Solution Approach 2:
The patent modifies the composition parameters of silver-based alloys, adjusting the ratio of silver to aluminum or other elements. By optimizing these compositional parameters, the material achieves both low resistivity from silver and improved gap-filling capability from the aluminum component.
4Ease of manufacture
If silver is deposited by sputtering, then deposition is achieved, but suitability for filling narrow gaps deteriorates
Solution Approach 1:
The patent uses composite silver-aluminum or silver-aluminum alloy materials that can be deposited by sputtering. The aluminum component in the composite improves wetting and capillary action during deposition, enabling effective filling of narrow gaps while maintaining the benefits of sputtering deposition.
Solution Approach 2:
The patent changes the material parameters by using silver-aluminum alloys instead of pure silver. This compositional change improves the deposition behavior in narrow gaps through enhanced wetting properties, while still allowing sputtering to be used as the deposition method.
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 method enables the formation of conductive elements with low resistivity, capable of filling narrow gaps and improving the reliability and performance of semiconductor interconnects by using silver or silver alloys with specific liner materials and annealing processes.
Implementation Method 1
annealing the structure to form an alloy of the first conductive material and silver
Implementation Method 2
annealing the structure to form an alloy of the first conductive material and silver
Data Source
AI summary
Methods of forming conductive elements, such as interconnects and electrodes, for semiconductor structures and memory cells. The methods include forming a first conductive material and a second conductive material comprising silver in a portion of at least one opening and performing a polishing process to fill the at least one opening with at least one of the first and second conductive materials. An annealing process may be performed to form a mixture or an alloy of the silver and the first conductive material. The methods enable formation of silver-containing conductive elements having reduced dimensions (e.g., less than about 20 nm). The resulting conductive elements have a desirable resistivity. The methods may be used, for example, to form interconnects for electrically connecting active devices and to form electrodes for memory cells. A semiconductor structure and a memory cell including such a conductive structure are also disclosed.