Dielectric Barrier Films Using PECVD and Oxygen Precursors
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Solution Overview
Problem
Current barrier dielectric films in microelectronics and other semiconductor applications face challenges in scaling down dielectric constants while maintaining adequate barrier properties, particularly due to disproportionate scaling with interlevel dielectrics, and require additional properties like transparency, wet chemical resistance, and mechanical strength.
Innovation Solution
The use of plasma-enhanced chemical vapor deposition (PECVD) processes with dimethyldiethoxysilane as a precursor, incorporating hydrogen and varying deposition conditions such as temperature and gas ratios, to form barrier dielectric films with reduced dielectric constants while maintaining high density and barrier properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the dielectric constant is reduced by transitioning to lower-k materials, then capacitance between copper lines is minimized, but density and adhesion properties deteriorate
Solution Approach 1:
The patent employs composite material structures by forming a barrier dielectric film composed of silicon oxycarbide with specific compositional ratios (Si:C:O in ranges of 40-60:10-30:20-50 atomic percent) that combine low dielectric constant properties with adequate density and adhesion. The composite nature is further enhanced by incorporating hydrogen and helium gases during PECVD to optimize film properties while maintaining structural integrity and bonding strength.
Solution Approach 2:
The patent applies parameter changes by precisely controlling deposition conditions including substrate temperature (200-400°C), pressure (1-100 mTorr), RF power (50-500 W), and gas flow rates to achieve optimal film composition and properties. By adjusting these parameters, the process produces films with dielectric constants in the range of 2.7-3.1 while maintaining density greater than 1.5 g/cc and excellent adhesion to copper features.
2Quantity of substance
If residence time of precursor is increased to achieve lower dielectric constants, then k value is reduced, but deposition time and productivity are reduced
Solution Approach 1:
The patent resolves this contradiction by optimizing multiple deposition parameters simultaneously: using substrate temperatures of 200-400°C, pressures of 1-100 mTorr, and specific precursor flow rates to achieve residence times of 10-100 milliseconds. This parameter optimization enables deposition rates of 50-500 nm/min while producing films with dielectric constants of 2.7-3.1, thus achieving both low-k values and high productivity.
Solution Approach 2:
The patent employs dynamic control of deposition conditions by adjusting gas flow rates, pressure, and temperature in real-time during the PECVD process to maintain optimal residence time windows. This dynamic adjustment allows the process to achieve low dielectric constants without sacrificing deposition rate or productivity.
3Temperature
If deposition temperature is reduced to protect underlying layers, then thermal budget is reduced, but film density and dielectric properties are compromised
Solution Approach 1:
The patent compensates for reduced thermal energy at lower deposition temperatures (200-400°C) by optimizing other parameters including increasing RF power (50-500 W), adjusting pressure (1-100 mTorr), and controlling gas composition with hydrogen and helium. These parameter changes enable the formation of dense films with density >1.5 g/cc and dielectric constants of 3.5 or greater even at reduced temperatures that protect underlying copper features from thermal damage.
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 reduces dielectric constants below 3.5 while achieving densities greater than 1.5 g/cc, enhancing barrier properties, thermal stability, and mechanical resistance, suitable for various semiconductor applications including integrated circuits and photovoltaics.
Implementation Method 1
forming a barrier dielectric film on the substrate using plasma enhanced chemical vapor deposition
Data Source
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AI summary
A method is provided for depositing a dielectric barrier film including a precursor with silicon, carbon, oxygen, and hydrogen with improved barrier dielectric properties including lower dielectric constant and superior electrical properties. This method will be important for barrier layers used in a damascene or dual damascene integration for interconnect structures or in other dielectric barrier applications. In this example, specific structural properties are noted that improve the barrier performance.