Variable Frequency Microwave Curing for Semiconductor Polymeric Films
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Solution Overview
Problem
The semiconductor industry faces challenges in efficiently curing and degassing polymeric films without introducing moisture and impurities, which can lead to outgassing during PVD processes, affecting the quality of metal layers and increasing processing time due to the need for separate curing and degassing steps.
Innovation Solution
A method using a processing chamber that integrates microwave radiation at variable frequencies to cure and degas polymeric films simultaneously, reducing moisture absorption and processing time by maintaining the substrate at a temperature below the thermal degas temperature while delivering microwave radiation to remove volatile compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal curing is performed in a conventional oven, then the polymeric film is cured, but moisture is adsorbed in the film and processing time increases due to vacuum breaks
Solution Approach 1:
The patent combines the curing process and degassing process into a single integrated microwave processing step. The microwave processing chamber performs both functions simultaneously, eliminating the need for separate thermal curing in a conventional oven and subsequent degassing under vacuum, thereby reducing processing time and eliminating vacuum breaks
Solution Approach 2:
The patent replaces the conventional thermal curing system (heating elements, convection fans) with a microwave-based heating system. The microwave radiation directly heats the polymeric film through dielectric heating, enabling faster and more uniform curing without the need for mechanical convection systems
2Ease of manufacture
If separate curing and PVD deposition equipment is used, then curing can be performed, but vacuum breaks occur resulting in moisture adsorption
Solution Approach 1:
The patent integrates the curing function into the PVD deposition chamber by installing a microwave generator within the vacuum chamber. This allows the polymeric film to be cured in-situ under vacuum conditions, eliminating the need to transfer substrates between separate curing and deposition equipment, thereby preventing moisture adsorption during transfer
Solution Approach 2:
The patent maintains a vacuum environment throughout the curing process by performing it within the sealed PVD chamber. The vacuum atmosphere prevents moisture and other contaminants from adsorbing onto the polymeric film during curing, ensuring film quality
3Productivity
If absorbed gaseous impurities are not removed prior to metal deposition, then processing is simpler, but outgassing occurs during PVD affecting metal layer quality
Solution Approach 1:
The patent performs degassing as a preliminary action before metal deposition by using microwave heating to remove absorbed gaseous impurities from the polymeric film and dielectric layers. This preliminary degassing step ensures that no outgassing occurs during subsequent PVD processes, guaranteeing metal layer quality
Solution Approach 2:
The patent implements continuous vacuum pumping during the microwave processing step to continuously remove outgassed impurities as they are released. This continuous action ensures that the vacuum environment is maintained throughout the curing and degassing process, preventing re-adsorption of moisture
4Reliability
If long degas times are used to remove moisture, then moisture is removed from films, but productivity is limited
Solution Approach 1:
The patent uses periodic microwave heating cycles with varying power levels to efficiently remove moisture. The microwave energy is delivered in controlled pulses that rapidly heat the material to drive off moisture, then allow cooling and vacuum pumping, creating an efficient periodic cycle that achieves thorough degassing in minimal time
Solution Approach 2:
The patent changes the heating parameter from conventional slow thermal conduction to rapid microwave dielectric heating. This parameter change enables much faster moisture removal by directly exciting water molecules with microwave radiation, reducing degas time from hours to minutes while maintaining effective moisture removal
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 allows for efficient curing and degassing in a single step, reducing processing time and preventing outgassing, thereby improving the quality of metal layers and increasing productivity by eliminating the need for separate equipment and vacuum breaks.
Implementation Method 1
directing a source of microwave radiation toward the uncured layer, the source of microwave radiation producing microwave radiation at a frequency selected from a frequency range of less than 7 GHz and delivering the microwave radiation at a variable frequency from the source of microwave radiation to the uncured layer
Implementation Method 2
The hard-cure can include heating at least the uncured layer to a hard-cure temperature
Implementation Method 3
delivering the microwave radiation at a variable frequency from the source of microwave radiation to the uncured layer, the variable frequency changing over a period of time
Data Source
AI summary
Methods and apparatus for processing a substrate are described herein. A vacuum multi-chamber deposition tool can include a degas chamber with both a heating mechanism and a variable frequency microwave source. The methods described herein use variable frequency microwave radiation to increased quality and speed of the degas process without damaging the various components.