Doped PVD Target Composition for Electromigration-Resistant Barriers
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Solution Overview
Problem
As integrated circuits are scaled to smaller dimensions, metal interconnects become increasingly susceptible to electromigration, leading to reliability issues and potential failure, necessitating an improvement in diffusion barrier layers to prevent conductive metal diffusion into adjacent dielectric layers.
Innovation Solution
A physical vapor deposition (PVD) process using a PVD target with a sputtering source material and intentionally introduced dopants like nickel, which affects the deposition rate and improves electromigration characteristics, forming a diffusion barrier layer that reduces electromigration effects and increases the lifetime of integrated circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If integrated circuits are scaled to smaller dimensions, then device density and integration are improved, but electromigration susceptibility increases leading to reliability degradation
Solution Approach 1:
The patent changes the chemical composition parameters of the diffusion barrier layer by incorporating specific dopants (such as tungsten, molybdenum, or rhenium) into the titanium nitride matrix. This compositional modification alters the material's electromigration resistance properties, enabling it to withstand the increased stress from smaller feature sizes and higher current densities without failing.
Solution Approach 2:
The patent creates a composite diffusion barrier layer by combining titanium nitride with metallic dopants (W, Mo, or Re). This composite structure leverages the excellent barrier properties of TiN while the added metals provide enhanced electromigration resistance, creating a material that outperforms pure TiN in scaled devices.
2Reliability
If dopants are introduced into the PVD target, then electromigration characteristics are improved, but deposition rate is affected
Solution Approach 1:
The patent optimizes the dopant concentration parameter within specific ranges (0.1-10 at% for W, Mo, or Re) to achieve the best balance between electromigration resistance and deposition rate. By carefully controlling this parameter, the material gains sufficient EM protection while maintaining acceptable manufacturing throughput.
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 PVD process with dopants enhances the electromigration resistance of the diffusion barrier layer, thereby improving the reliability and performance of integrated circuits by reducing the susceptibility to electromigration, thus extending their lifespan.
Implementation Method 1
positioning the substrate into a physical vapor deposition (PVD) chamber facing a PVD target including a target plate. The target plate includes a sputtering source material and a dopant, wherein the dopant is not an impurity in the sputtering source material. sputtering the PVD target to deposit a diffusion barrier layer on sidewall and bottom surfaces of the contact opening
Data Source
AI summary
A physical vapor deposition (PVD) target for performing a PVD process is provided. The PVD target includes a backing plate and a target plate coupled to the backing plate. The target plate includes a sputtering source material and a dopant, with the proviso that the dopant is not impurities in the sputtering source material. The sputtering source material includes a diffusion barrier material.