Cryogenic Moisture Trap for Stable Etch Chamber Moisture Control
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Solution Overview
Problem
Mechanical pumps are inadequate for effectively removing moisture from semiconductor processing chambers, leading to moisture accumulation that affects etch rate and uniformity, necessitating frequent chamber opening and prolonged maintenance.
Innovation Solution
A moisture trap apparatus with a cryogenic coil and outer casing is integrated into the exhaust system, condensing and freezing moisture within the trap to regulate moisture levels without opening the chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical pumps are used to exhaust moisture from the pre-clean chamber, then the exhaust system is simple, but the moisture removal effectiveness is insufficient
Solution Approach 1:
A moisture trap is introduced as an intermediary component in the exhaust line between the pre-clean chamber and mechanical pump. The trap captures and removes moisture through condensation and adsorption mechanisms, allowing the mechanical pump to continue functioning while effectively removing moisture that would otherwise accumulate in the chamber.
Solution Approach 2:
The moisture trap utilizes phase transition of water from vapor to liquid (condensation) to remove moisture from the exhaust stream. The cooling surfaces within the trap cause water vapor to condense into liquid droplets that are then collected and removed, significantly improving moisture removal effectiveness without requiring a different pumping mechanism.
2Reliability
If the chamber is opened during preventative maintenance to remove moisture, then moisture accumulation is reduced, but maintenance time increases
Solution Approach 1:
The moisture trap operates continuously during chamber operation to remove moisture as it is generated, eliminating the need for periodic chamber opening and baking procedures. This continuous moisture removal maintains stable chamber conditions throughout extended production runs, significantly reducing maintenance frequency and time.
Solution Approach 2:
The moisture trap proactively removes moisture before it can accumulate to problematic levels in the chamber. By continuously capturing and removing water vapor in the exhaust line, the system prevents moisture buildup that would otherwise require time-consuming maintenance interventions.
3Reliability
If frequent purging and heating of the process chamber is performed to reduce moisture, then moisture levels are temporarily reduced, but productivity decreases
Solution Approach 1:
The moisture trap serves as an intermediary moisture removal system that operates independently of the chamber processes. It continuously removes moisture from the exhaust line without requiring chamber interruption, purging, or heating cycles, thereby maintaining stable moisture levels while preserving production efficiency.
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 apparatus efficiently removes moisture, maintaining chamber integrity and reducing maintenance time by continuously regulating moisture levels, thereby improving etch rate and uniformity.
Implementation Method 1
condensing and freezing moisture from the exhaust line onto an inner surface of the moisture trap
Implementation Method 2
condensing and freezing moisture from the exhaust line onto an inner surface of the moisture trap
Implementation Method 3
flowing a cryogenic fluid through a cryogenic coil within the moisture trap
Data Source
AI summary
A moisture trap for use with a semiconductor processing chamber is described. The moisture trap is utilized during preventative maintenance of the processing chamber to remove moisture from the processing chamber. The moisture trap is attached to an exhaust line of the processing chamber and includes a body having an inner surface that forms a cavity for the moisture to condense and freeze. A cryogenic coil is disposed around the body of the moisture trap. A valve is disposed between the body of the moisture trap and the exhaust line and is opened during preventative maintenance.