Masking Layer for Selective Capping in Semiconductor Devices
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Solution Overview
Problem
Current methods for forming a capping layer on electrically conductive regions in electronic devices fail to adequately inhibit electromigration and diffusion, leading to issues like current leakage and increased capacitance, especially as device features shrink.
Innovation Solution
A masking layer is formed on the dielectric region to prevent the formation of capping layer material on or in the dielectric region, allowing for the use of materials and processes that enhance adhesion and inhibit electromigration without increasing resistance, and enabling the use of porous dielectric materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a capping layer is formed on electrically conductive regions to inhibit electromigration, then reliability is improved, but capacitance increases
Solution Approach 1:
The patent applies different materials with specific properties to different locations: a first capping layer material is used on electrically conductive regions to inhibit electromigration, while a second capping layer material with lower dielectric constant is used on dielectric regions to reduce capacitance. This local differentiation resolves the contradiction by optimizing each region's material properties for its specific function.
Solution Approach 2:
The patent employs a composite capping layer structure consisting of two different materials: a first capping layer material (such as tungsten, cobalt, or nickel) that provides electromigration inhibition, and a second capping layer material (such as silicon dioxide or silicon nitride) that provides lower capacitance. This composite approach allows simultaneous achievement of both reliability improvement and capacitance reduction.
2Reliability
If materials and processes are selected to enhance adhesion and inhibit electromigration, then reliability is improved, but resistance increases
Solution Approach 1:
The patent uses a first capping layer material specifically on electrically conductive regions where electromigration inhibition is needed, rather than using materials that would increase resistance. The local application of appropriate materials ensures reliability improvement without the harmful side effect of increased resistance in the conductive paths.
3Ease of manufacture
If conventional methods are used to form capping layers, then manufacturing is simplified, but electromigration and diffusion are not adequately inhibited
Solution Approach 1:
The patent changes the material parameters of the capping layer by using different materials for different regions. The first capping layer material is selected from tungsten, cobalt, nickel or their alloys, while the second material is selected from silicon dioxide, silicon nitride, or porous low-k dielectric materials. This parameter change in material composition enables adequate inhibition of electromigration and diffusion while maintaining ease of manufacture through established deposition techniques.
4Ease of manufacture
If non-porous dielectric materials are used, then manufacturing is easier, but device performance is limited
Solution Approach 1:
The patent employs composite dielectric structures including both non-porous dielectric materials (for ease of manufacture) and porous low-k dielectric materials (for improved device performance). The porous dielectric materials are used in specific regions where performance enhancement is needed, while non-porous materials are used where manufacturing simplicity is prioritized, achieving a balance between the two requirements.
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 effectively inhibits electromigration and diffusion, reducing current leakage and capacitance, while allowing for flexible material and process selection for the capping layer, and enables the use of porous dielectric materials, improving the performance and reliability of electronic devices.
Implementation Method 1
a masking layer is formed on a dielectric region so that, during subsequent formation of a capping layer on electrically conductive regions
Data Source
AI summary
A masking layer is formed on a dielectric region of an electronic device so that, during subsequent formation of a capping layer on electrically conductive regions of the electronic device that are separated by the dielectric region, the masking layer inhibits formation of capping layer material on or in the dielectric region. The capping layer can be formed selectively on the electrically conductive regions or non-selectively; in either case (particularly in the latter), capping layer material formed over the dielectric region can subsequently be removed, thus ensuring that capping layer material is formed only on the electrically conductive regions. Silane-based materials, such as silane-based SAMs, can be used to form the masking layer. The capping layer can be formed of an electrically conductive material (e.g., a cobalt alloy, a nickel alloy, tungsten, tantalum, tantalum nitride), a semiconductor material, or an electrically insulative material, and can be formed using any appropriate process, including conventional deposition processes such as electroless deposition, chemical vapor deposition, physical vapor deposition or atomic layer deposition.