Semiconductor Substrate Cleaning via IPA Drying and Lamp Annealing
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Solution Overview
Problem
The refinement of semiconductor devices has made it challenging to dry semiconductor substrates without collapsing fine patterns, as conventional spin drying and even IPA drying methods still cause adverse effects due to capillary forces from surface tension, especially in patterns below the 30-nanometer generation.
Innovation Solution
A cleaning apparatus using a belt conveyor with a treatment head that applies acidic rinse water at 70°C or above for less than 10 seconds, followed by IPA drying with lamp annealing and pressure reduction above the substrate to minimize capillary forces and pattern deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If spin drying is used to remove rinse water, then water is effectively removed from the semiconductor substrate, but fine patterns collapse due to capillary force from surface tension
Solution Approach 1:
The invention changes the physical parameters of the drying medium by using IPA (isopropyl alcohol) instead of water. IPA has a surface tension of approximately one-third that of water, which significantly reduces the capillary force acting on fine patterns during drying. This parameter change allows effective water removal while minimizing pattern collapse.
Solution Approach 2:
The invention introduces IPA as an intermediary substance to replace water in the drying process. IPA serves as a intermediate drying agent that can effectively remove water while its lower surface tension prevents the harmful capillary forces that cause pattern collapse in conventional water-based spin drying.
2Manufacturing precision
If IPA drying is used instead of spin drying, then pattern collapse is reduced, but throughput is insufficient for refined devices after 30-nanometer generation
Solution Approach 1:
The invention merges multiple drying mechanisms into a single integrated drying head: IPA spraying for liquid drying, lamp heating for thermal evaporation, and vacuum decomposition for pressure reduction. This combination achieves both high pattern integrity and sufficient throughput for refined devices.
Solution Approach 2:
The invention utilizes phase transitions of IPA in multiple forms: liquid IPA spray for initial drying, vaporized IPA from lamp heating for evaporative drying, and vacuum-decomposed IPA for final moisture removal. These sequential phase transitions enable comprehensive drying while maintaining pattern integrity.
3Loss of time
If conventional drying methods are used, then processing time is reduced, but adverse influences on refined patterns increase
Solution Approach 1:
The invention implements continuous drying action through sequential operations: immediate IPA spraying upon substrate entry, continuous lamp heating during conveyance, and sustained vacuum application. This continuous multi-mechanism drying eliminates idle time while maintaining low capillary force throughout the entire process, preventing pattern 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 significantly reduces pattern collapse ratios and defect densities, ensuring high pattern survival rates even in fine line-and-space patterns with high aspect ratios, effectively addressing the limitations of previous drying methods.
Implementation Method 1
applies heat to the rinse water thereby to set a temperature of the rinse water to 70° or above
Implementation Method 2
an optical mechanism configured to recognize a pattern on the semiconductor substrate
Implementation Method 3
a drying treatment mechanism executing both a drying treatment with use of a drying solvent and lamp annealing
Implementation Method 4
to depressurize a part of the semiconductor substrate, which part is under the drying treatment
Implementation Method 5
a drying treatment with use of a drying solvent and lamp annealing
Data Source
AI summary
A cleaning apparatus for a semiconductor substrate includes a belt conveyor, a treatment head that executes cleaning, rinsing and drying treatments, a rinse water supplying mechanism that supplies rinse water adjusted to a predetermined pH value to the treatment head and configured to rinse the substrate applies heat to the rinse water to set a rinse water temperature to 70° or above, and an optical mechanism. The treatment head is configured to rinse the substrate. The optical mechanism is configured to recognize a pattern on the semiconductor substrate so that the semiconductor substrate can be automatically placed on the belt conveyor with a direction of the recognized pattern and a feeding direction of the belt conveyor having a predetermined relationship. The treatment head includes a drying treatment mechanism configured to execute both a drying treatment with use of drying solvent and lamp annealing in execution of drying treatment.