Wafer-Form UV LED Desorption Device for Vacuum Chamber Leak Testing
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Solution Overview
Problem
Current leak testing methods in wafer processing tools are inefficient due to lengthy pump down times caused by water molecules absorbed in chamber walls, requiring substantial time to reach a test pressure of 10−4 Torr, and dedicated lamps are not transferable between chambers and require specific modifications.
Innovation Solution
A desorption device with a substrate of wafer form factor equipped with light emitting diodes (LEDs) that emit UV radiation to uniformly irradiate chamber walls, reducing chamber pressure quickly and allowing for effective leak testing without the need for external power or modifications to the vacuum chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional pump down methods are used to achieve test pressure, then the vacuum chamber can be tested for leaks, but the process takes substantial time due to water molecules absorbed in chamber walls
Solution Approach 1:
The patent applies preliminary action by using UV irradiation to desorb water molecules from chamber walls before the pump down process begins. The desorption device is installed in the vacuum chamber and activated prior to pumping, pre-cleaning the chamber surfaces of absorbed water molecules that would otherwise slow down the vacuum achievement process.
Solution Approach 2:
The patent replaces the purely mechanical pump down process with a combined photophysical- mechanical approach. UV LEDs emit ultraviolet radiation that causes desorption of water molecules from chamber surfaces, substituting the need for extended mechanical pumping time with a faster photophysical desorption mechanism followed by shorter pump down time.
2Productivity
If dedicated lamps are used for desorption, then water molecules can be removed from chamber walls, but the lamps are not transferable between chambers and require specific modifications
Solution Approach 1:
The patent applies universality by designing a desorption device with UV LEDs that can be transferred and used in multiple different vacuum chambers. The device is made portable and adaptable, eliminating the need for dedicated fixed installations in each chamber. The same desorption unit can serve multiple chambers across different processing tools, reducing overall system complexity and installation requirements.
Solution Approach 2:
The patent implements dynamics by making the desorption device movable and reconfigurable rather than fixed. The UV LED array can be positioned and adjusted within different chamber configurations, allowing flexible deployment across various chamber sizes and geometries without requiring permanent modification of each chamber.
3Speed
If UV radiation is used to desorb molecules from chamber walls, then the achievement of test pressure is accelerated, but heat must be managed from the LEDs
Solution Approach 1:
The patent uses thermal paste as a thermal intermediary material between the UV LED chips and the heat sink. This thermal interface material efficiently transfers heat generated by the LEDs to the heat sink, enabling effective thermal management. The heat sink then dissipates this heat to the surrounding environment, maintaining LED operating temperatures within acceptable ranges during high-power UV irradiation for rapid desorption.
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 desorption device accelerates the achievement of a test pressure of 10−4 Torr or less, enabling quicker and more effective manufacturing quality testing of vacuum chambers in wafer processing tools.
Implementation Method 1
several light emitting diodes (LEDs) are mounted on the support surface. The LEDs emit ultraviolet (UV) radiation when electrically powered
Implementation Method 2
The LEDs may emit UV radiation in a UV C range
Implementation Method 3
a heat exchanger is thermally coupled to at least one of the LEDs to transfer heat away from the LEDs
Implementation Method 4
the heat exchanger may be a thermoelectric cooling device
Implementation Method 5
several heat pipes may extend from respective LEDs mounted on the insulated cover, through the insulated cover to the heat exchanger
Data Source
AI summary
Embodiments include devices and methods for desorbing molecules from a chamber wall. In an embodiment, a desorption device includes several light emitting diodes (LEDs) mounted on a substrate having a wafer form factor. The LEDs may emit ultraviolet (UV) radiation, such as UV radiation in a UV C range. In an embodiment, the LEDs are thermally coupled to a heat exchanger, such as a thermoelectric cooling device. The emitted radiation may uniformly irradiate a chamber wall to desorb water molecules from the chamber wall. Other embodiments are also described and claimed.