Load Lock Device Purge Gas Cooling
Solution Overview
Problem
In multi-chamber vacuum processing systems, high-temperature wafers are inefficiently cooled in load lock devices, leading to potential wafer bending and contamination from purge gas particles, which slows down processing throughput.
Innovation Solution
A load lock device with a variable internal pressure vessel, a cooling member, and a purge gas supply system that uses a first purge gas discharging member to create a laminar flow parallel to the wafer and a second porous discharging member to gently supply gas to the wafer's bottom surface, controlling turbulent flow and preventing particle adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the wafer is rapidly cooled by placing it close to the cooling plate, then the cooling efficiency is improved, but the wafer may be bent due to thermal expansion difference between front and rear surfaces
Solution Approach 1:
The cooling function is segmented into two independent systems: a cooling plate for the rear surface and a purge gas supply system for the front surface. This allows each system to operate independently at optimal positions without interfering with wafer flatness while achieving efficient cooling of both surfaces simultaneously.
Solution Approach 2:
Purge gas is introduced as an intermediary cooling medium for the front surface of the wafer. The gas flows in parallel with the wafer surface, providing cooling without direct contact, thus preventing wafer bending while maintaining cooling efficiency.
2Object-affected harmful factors
If the purge gas is supplied from a position far from the wafer to prevent particle adhesion, then wafer contamination is reduced, but cooling efficiency deteriorates
Solution Approach 1:
The gas supply function is segmented into two separate discharging members: one positioned far from the wafer to supply purge gas for contamination prevention, and another (porous) member positioned close to supply cooling gas directly to the wafer surface. This segmentation allows both distant positioning for cleanliness and close positioning for cooling efficiency to coexist.
Solution Approach 2:
A porous discharging member is used to supply purge gas gently to the wafer surface. The porous structure diffuses the gas flow, reducing turbulence and particle generation while maintaining efficient thermal contact with the wafer for effective cooling.
3Manufacturing precision
If the wafer is placed far above the cooling plate to prevent bending, then wafer flatness is maintained, but cooling time increases and throughput deteriorates
Solution Approach 1:
The cooling function is segmented between rear surface cooling (via cooling plate) and front surface cooling (via purge gas). This allows the wafer to be positioned close to the cooling plate for efficient rear surface cooling without causing bending, while the front surface is cooled simultaneously by purge gas flow.
Solution Approach 2:
Purge gas is used as a pneumatic cooling medium for the front surface of the wafer. The gas flow provides efficient heat removal from the front surface, complementing the cooling plate's action on the rear surface, thereby reducing total cooling time without compromising wafer flatness.
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 configuration enables efficient cooling of high-temperature wafers while preventing particle adhesion, thereby improving processing throughput and maintaining wafer integrity.
Implementation Method 1
a cooling member, having a cooling device, provided within the vessel and configured to cool the substrate while the substrate is placed adjacent thereto
Implementation Method 2
a first purge gas discharging member configured to discharge the purge gas supplied from the purge gas supply unit to flow in parallel with the substrate while controlling a turbulent flow of the purge gas
Implementation Method 3
a second purge gas discharging member formed of a porous material and configured to discharge the purge gas toward a bottom surface of the substrate from below the substrate placed adjacent to the cooling member
Data Source
AI summary
A load lock device includes a vessel of which an internal pressure is variable between a pressure corresponding to a vacuum chamber and an atmospheric pressure; a purge gas supply source configured to supply a purge gas into the vessel; an exhaust device configured to evacuate an inside of the vessel; a pressure controller configured to adjust the internal pressure of the vessel to be the pressure corresponding to the vacuum chamber and the atmospheric pressure; a cooling member within the vessel configured to cool a substrate while the substrate is placed adjacent thereto; a first purge gas discharging member configured to discharge the purge gas to flow in parallel with the substrate while controlling a turbulent flow thereof; and a second purge gas discharging member formed of a porous material and configured to discharge the purge gas toward a bottom surface of the substrate from below the substrate.