Low-k Dielectric Film Curing via Combined IR and UV Radiation
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Solution Overview
Problem
Conventional thermal curing methods for low-k dielectric films are inefficient in achieving adequate cross-linking and mechanical strength, especially for ultra-low-k films with high porosity, due to limited energy absorption and initiator generation, leading to insufficient mechanical properties for robust interconnect structures.
Innovation Solution
Exposing low-k dielectric films to a combination of infrared (IR) and ultraviolet (UV) radiation, with varying intensities and durations, to generate cross-linking initiators and enhance mechanical properties without degrading electrical or physical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermal curing is used to cure porous low-k dielectric films, then the process is simple and equipment is available, but the mechanical strength and cross-linking degree are insufficient
Solution Approach 1:
The patent combines infrared radiation and ultraviolet radiation into a single curing process. The infrared component heats the film to promote mobility of polymer chains, while the UV component provides energy for cross-linking reactions. This combination achieves superior mechanical strength and cross-linking degree compared to thermal curing alone, resolving the contradiction between simplicity and effectiveness.
Solution Approach 2:
The patent replaces the conventional thermal curing mechanism with a radiation-based curing mechanism. Instead of relying solely on heat conduction from a furnace, the invention uses electromagnetic radiation (infrared and ultraviolet) to directly energize the polymer chains and initiate cross-linking. This substitution provides more efficient energy transfer and better control over the curing process, achieving adequate mechanical strength that thermal curing cannot provide.
2Quantity of substance
If high porosity is introduced to reduce dielectric constant, then the electrical insulation is improved, but the mechanical robustness deteriorates
Solution Approach 1:
The patent changes the curing parameters by introducing infrared and ultraviolet radiation with specific wavelength ranges and intensity levels. The infrared radiation (wavelength 700nm-1mm) provides thermal energy to increase polymer chain mobility, while UV radiation (wavelength 10nm-400nm) provides the activation energy for cross-linking. This parameter change enables the formation of a robust cross-linked network even in highly porous films, maintaining mechanical strength while achieving low dielectric constant.
Solution Approach 2:
The patent creates a composite curing approach where infrared radiation and ultraviolet radiation work synergistically. The infrared component prepares the material by heating and increasing molecular mobility, while the UV component performs the actual cross-linking. This composite energy input creates a more effective curing process that can handle high porosity materials, achieving both low dielectric constant and adequate mechanical robustness.
3Strength
If thermal curing temperature is increased to improve cross-linking, then the mechanical properties are enhanced, but the film may be damaged or degraded
Solution Approach 1:
The patent segments the curing energy into two distinct components: infrared radiation for heating and ultraviolet radiation for cross-linking. This segmentation allows each radiation type to perform its specific function at optimal energy levels. The infrared component heats the film to promote chain mobility without causing degradation, while the UV component provides the precise energy needed for cross-linking. This segmentation prevents the film damage that can occur with excessive thermal curing temperatures.
Solution Approach 2:
The patent uses infrared radiation as an intermediary to prepare the polymer chains for cross-linking. The infrared energy increases molecular mobility and reduces viscosity, creating a more favorable state for subsequent UV-induced cross-linking. This intermediary heating step allows the cross-linking reaction to proceed more efficiently at lower overall temperatures, preventing film degradation while still achieving enhanced mechanical properties.
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 IR and UV radiation treatment significantly improves the mechanical strength and dielectric properties of low-k films, achieving a lower dielectric constant while maintaining or improving film robustness and hydrophobicity.
Implementation Method 1
exposing the low-k dielectric film to infrared (IR) radiation
Implementation Method 2
exposing the low-k dielectric film to infrared (IR) radiation
Implementation Method 3
exposing the low-k dielectric film to ultraviolet (UV) radiation... free radical polymerization is understood to be the primary route for cross-linking
Implementation Method 4
exposing the low-k dielectric film to ultraviolet (UV) radiation... generate cross-linking initiators
Data Source
AI summary
A method of curing a low dielectric constant (low-k) dielectric film on a substrate is described, wherein the dielectric constant of the low-k dielectric film is less than a value of approximately 4. The method comprises exposing the low-k dielectric film to infrared (IR) radiation and ultraviolet (UV) radiation.