Low-Frequency PECVD for Hard Low-k Dielectric Films
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Solution Overview
Problem
Conventional methods for producing low-k films in semiconductor processing often require additional processing steps like UV curing to enhance hardness, which increases production costs and reduces throughput due to the need for multiple chambers and complex processing operations.
Innovation Solution
The method involves depositing a silicon-oxygen-and-carbon-containing material using a plasma-enhanced chemical vapor deposition process at a frequency below 15 MHz, with specific precursor characteristics and higher substrate temperatures to achieve high hardness and low dielectric constant without subsequent treatments like UV exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional plasma-enhanced deposition methods are used to form low-k films, then the dielectric constant is reduced, but the hardness and Young's modulus of the film decrease
Solution Approach 1:
The patent changes the plasma frequency parameter from conventional high frequency (e.g., 13.56 MHz) to low frequency (e.g., 40-100 kHz). This parameter change fundamentally alters the plasma characteristics and ion bombardment energy, enabling simultaneous achievement of low dielectric constant (3.0-3.3) and high hardness (3.5-6.0 GPa) in the deposited film
Solution Approach 2:
The patent uses a composite precursor containing silicon, oxygen, and carbon elements in specific ratios (C:Si > 1, O:Si > 1.5). This composite material approach allows the film to incorporate multiple elements that work together to achieve both low dielectric constant and high mechanical strength properties
2Strength
If additional processing steps like UV curing are applied to enhance film hardness, then the hardness is improved, but the production cost increases and throughput decreases
Solution Approach 1:
The patent performs the hardness-enhancing action during the deposition process itself rather than as a subsequent step. By using low frequency plasma during deposition, the film is deposited with inherently high hardness, eliminating the need for post-deposition UV curing or other enhancement steps
Solution Approach 2:
The patent merges the deposition process with the hardness enhancement function into a single step. The low frequency plasma deposition simultaneously deposits the film and imparts high hardness through controlled ion bombardment and microstructure formation, combining multiple functions into one process
3Reliability
If multiple processing chambers are used to achieve both low dielectric constant and high hardness, then the film quality is improved, but the device complexity and production cost increase
Solution Approach 1:
The patent makes the deposition chamber multi-functional by enabling it to simultaneously achieve low dielectric constant and high hardness through low frequency plasma. This single chamber performs what previously required multiple specialized chambers, reducing system complexity while maintaining film quality
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 results in low-k films with improved hardness and Young's modulus, reducing the need for additional processing steps and chambers, thereby lowering production costs and increasing efficiency.
Implementation Method 1
The methods may include forming a plasma within the processing region of the silicon-oxygen-and-carbon-containing precursor. The plasma may be formed at a frequency below 15 MHz (e.g., 13.56 MHz). The methods may include depositing a silicon-oxygen-and-carbon-containing material on the substrate.
Data Source
AI summary
Exemplary methods of forming a silicon-and-carbon-containing material may include flowing a silicon-oxygen-and-carbon-containing precursor into a processing region of a semiconductor processing chamber. A substrate may be housed within the processing region of the semiconductor processing chamber. The methods may include forming a plasma within the processing region of the silicon-and-carbon-containing precursor. The plasma may be formed at a frequency less than 15 MHz (e.g., 13.56 MHz). The methods may include depositing a silicon-and-carbon-containing material on the substrate. The silicon-and-carbon-containing material as-deposited may be characterized by a dielectric constant below or about 3.5 and a hardness greater than about 3 Gpa.