Copper Electrode Sidewall Barrier Layers for Oxidation Control
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Solution Overview
Problem
Copper electrodes in semiconductor devices face issues such as diffusion into neighboring layers and oxidation, which can lead to increased leakage current and conductivity issues, especially during the formation of passivation layers at elevated temperatures.
Innovation Solution
A semiconductor device with a patterned metallic electrode featuring a sidewall barrier layer formed by exposing the electrode to a manganese precursor and subsequent oxidation, creating a manganese oxide layer that prevents oxidation and maintains conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper electrodes are used due to their low electrical resistivity, then electrical conductivity is improved, but copper may diffuse into neighboring semiconductor layers increasing leakage current
Solution Approach 1:
The electrode structure is segmented into multiple functional layers: a copper electrode layer for conductivity, a barrier layer to prevent diffusion, and a sidewall barrier layer for lateral protection. This segmentation allows each layer to perform its specific function without interfering with others.
Solution Approach 2:
A barrier layer is introduced as an intermediary between the copper electrode and the semiconductor layer. This intermediate layer prevents direct contact and diffusion of copper into the semiconductor, thereby eliminating the harmful effect while preserving the low-resistivity benefit of copper.
2Ease of manufacture
If copper electrodes are exposed to oxygen at elevated temperatures during passivation layer formation, then passivation layers can be formed, but copper oxidation occurs adversely impacting electrode conductivity
Solution Approach 1:
The sidewall barrier layer is formed preliminarily on the copper electrode before the passivation layer formation process. This preliminary protective layer prevents oxidation of copper during subsequent high-temperature processing, countering the harmful oxidation effect before it can occur.
Solution Approach 2:
The sidewall barrier layer, which initially serves to protect the copper electrode, inadvertently provides an additional benefit by preventing copper oxidation during passivation layer formation. This converts a protective measure into a dual-function solution that addresses both diffusion prevention and oxidation protection.
3Reliability
If sidewall barrier layers are added to prevent copper diffusion and oxidation, then reliability is improved, but device complexity increases
Solution Approach 1:
The sidewall barrier layer is applied locally only where needed - specifically on the sidewalls of the copper electrode - rather than uniformly across the entire electrode structure. This localized application provides protection precisely where diffusion and oxidation occur while minimizing unnecessary material addition and structural complexity.
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 sidewall barrier layer effectively prevents oxidation of the metallic electrodes, maintaining consistent conductivity and improving the performance of semiconductor devices by maintaining the variability of gate overlap regions within a predetermined threshold.
Implementation Method 1
heating the substrate to a deposition temperature of at least 300° C.; and exposing the patterned electrode structure to a manganese precursor at the deposition temperature within a deposition chamber for a deposition period
Implementation Method 2
exposing the patterned electrode structure to an oxide that reacts with the manganese precursor to form an MnOx barrier layer disposed locally on the sidewall
Data Source
AI summary
The present disclosure includes a semiconductor device comprising a substrate including a device surface and a patterned metallic electrode disposed on the substrate. The patterned metallic electrode is formed of one or more of copper, gold, and silver. The patterned metallic electrode comprises a lower surface proximate to the substrate, an upper surface, and a sidewall extending between the lower surface and the upper surface a sidewall barrier layer extending over the sidewall. The sidewall barrier layer may be a manganese oxide barrier layer.