UV-Treated CDO Films for Ultra-Low Dielectric Constant
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Solution Overview
Problem
Current methods for producing ultra-low dielectric constant (ULK) carbon-doped oxide (CDO) films face challenges in achieving both low dielectric constants and high mechanical strength, often requiring dual precursors that lead to degraded mechanical properties and vulnerability to chemical penetration.
Innovation Solution
The method involves using a single precursor for CDO film deposition via plasma-enhanced chemical vapor deposition (PECVD) followed by UV-assisted thermal processing (UVTP) to increase cross-linking, thereby achieving ultra-low dielectric constants below 2.7 with high mechanical strength, eliminating the need for a porogen removal step and enhancing chemical inertness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If dual precursors (porogen and backbone) are used to achieve ultra-low dielectric constants, then the dielectric constant is reduced below 2.7, but the mechanical strength is degraded and chemical inertness is reduced
Solution Approach 1:
The invention extracts and eliminates the porogen component from the dual-precursor system, using only a backbone precursor to form the dielectric film. This removes the source of mechanical degradation and chemical vulnerability while maintaining the low-k structure through alternative mechanisms (controlled porosity without porogen, or dense structure with different composition).
Solution Approach 2:
The invention changes the compositional parameters by using a single precursor with specific carbon content and structure (e.g., silicon-containing precursors with controlled organic groups) to achieve the desired dielectric constant while maintaining mechanical integrity. The precursor selection and deposition parameters are optimized to balance low-k properties with strength.
2Quantity of substance
If additional free space is incorporated to reduce dielectric constant below 2.7, then the capacitance and RC delay are reduced, but the mechanical properties are degraded
Solution Approach 1:
The invention utilizes controlled porosity to reduce the dielectric constant while managing mechanical properties. By creating a porous structure through single precursor deposition (without porogen), the film achieves low-k values through void space that does not compromise the remaining material's mechanical strength or chemical stability.
Solution Approach 2:
The invention creates a composite-like structure within the single precursor system, where the dielectric film contains both organic and inorganic phases with different functions. The organic groups provide low-k characteristics while the inorganic network maintains mechanical strength, achieving a balanced composite structure from a single precursor.
3Quantity of substance
If porogen is driven out during cure step to create free space, then the dielectric constant is reduced, but moisture and solvent penetration is increased
Solution Approach 1:
The invention removes the porogen component entirely from the process, eliminating the creation of large voids and interconnected pores that facilitate moisture and solvent penetration. The resulting film structure, formed without porogen, has controlled porosity or denser structure that resists chemical penetration while maintaining low-k properties.
Solution Approach 2:
The single precursor system creates a more chemically inert film structure that resists penetration by moisture and solvents. The absence of porogen and its decomposition products, along with the formation of a more uniform and stable matrix, provides better chemical resistance and protects against harmful environmental factors.
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 CDO films with dielectric constants as low as 2.5 and mechanical strengths of at least 7.5 GPa, comparable to dual precursor methods, while reducing out-gassing and improving chemical resistance, thus addressing the limitations of existing ULK film technologies.
Implementation Method 1
The methods involve contacting the substrate with a CDO precursor to deposit the film typically using a plasma-enhanced chemical vapor deposition (PECVD) method
Implementation Method 2
After the film is deposited, it is exposed to ultraviolet radiation in a manner that increases cross-linking and/or lowers the dielectric constant of the film
Data Source
AI summary
Methods of preparing low-k carbon-doped oxide (CDO) films having high mechanical strength are provided. The methods involve contacting the substrate with a CDO precursor to deposit the film typically using a plasma-enhanced chemical vapor deposition (PECVD) method. After the film is deposited, it is exposed to ultraviolet radiation in a manner that increases cross-linking and/or lowers the dielectric constant of the film. The resulting films have ultra-low dielectric constants, e.g., about 2.5, but also high mechanical strength, e.g., a modulus of at least about 7.5 GPa. In certain embodiments, a single hydrocarbon precursor is used, resulting in an improved process for obtaining ULK films that does not require dual (porogen and backbone) precursors.