Edwards CTI Kryogenics On Board 8F Enhanced Cryopump Explanation

Edwards CTI Kryogenics Enhanced On Board 8F Cryopump: A Vacuum Performance Revolution in Semiconductor Sputtering Processes

Introduction: The core role and regeneration bottleneck of low-temperature pumps in semiconductor sputtering

In modern semiconductor manufacturing, physical vapor deposition (PVD) sputtering technology is widely used to deposit metal thin films such as aluminum, titanium, and titanium nitride. This process requires the chamber to reach a high vacuum (usually at the level of 10-7Torr) in a very short period of time to ensure film uniformity and adhesion. Cryopump has become a standard vacuum acquisition device for sputtering equipment due to its high pumping speed and oil-free cleanliness characteristics for gases, especially water vapor, argon, and nitrogen.

However, the "regeneration" of the cryogenic pump - that is, regularly heating and releasing the captured gas and extracting it - is an unavoidable maintenance step. During the regeneration period, the process chamber cannot produce, directly affecting the tool availability of the equipment. After multiple process cycles, the vacuum recovery speed of traditional cryogenic pumps gradually decreases, resulting in an increase in regeneration frequency and a regeneration time of several hours, which seriously affects wafer output.

The Enhanced On Board 8F cryogenic pump launched by Edwards CTI Kryogenics is designed to solve this contradiction. It significantly improves vacuum recovery performance through internal optimization while maintaining the exact same external dimensions, interfaces, and pumping speed as the original On Board 8F and Cryo Torr 8F, reducing regeneration frequency by half and significantly increasing equipment availability. This article will delve into its technical details and engineering value.

The correlation between vacuum recovery performance and regeneration frequency

2.1 The Importance of Vacuum Recovery Steps

In the sputtering process, after each deposition cycle, the process gas (such as argon or nitrogen) needs to be turned off, and then the chamber is quickly evacuated to a specified high vacuum level (such as 1 × 10 − 7 Torr), which is called "vacuum recovery". The speed of recovery directly determines when the next batch of wafers can start processing. If the recovery is slow, the process cycle may be extended, and the membrane quality may be affected by residual gases.

2.2 Recovery performance degradation leads to frequent regeneration

As the operating time of the low-temperature pump increases, the adsorbed argon, nitrogen, and water vapor inside gradually accumulate, resulting in a decrease in the effective pumping speed of the pump, especially in high load areas. This directly results in a prolonged vacuum recovery time, and when the recovery time exceeds the allowed window of the process, regeneration must be performed. Traditional On Board 8F may require 4-6 regenerations per month in typical argon or nitrogen/argon mixed processes, with each shutdown lasting more than 2.5 hours, resulting in significant production capacity losses.

Core improvement of Enhanced On Board 8F: persistent recovery performance

3.1 Improvement mechanism and effect

By optimizing the adsorption structure and thermal management of the low-temperature plate, the enhanced 8F significantly prolongs the maintenance time of the "rapid recovery" state while maintaining the same pumping rate (hydrogen 2200 l/s, air 1500 l/s, water vapor 4000 l/s, argon 1200 l/s). The recovery performance curve provided in the data manual shows:

In the pure argon process, the vacuum recovery time of enhanced 8F can still be maintained at a very low level after long-term operation, and the number of regeneration triggers is significantly reduced.

In the nitrogen/argon mixed process (>50% N ₂), its recovery performance is also excellent, significantly extending the regeneration interval compared to traditional models.

Specific data shows that users can reduce the average monthly regeneration frequency by 40% to 65%. For example, if the original regeneration needs to be done 5 times a month, the enhanced regeneration can be reduced to 2-3 times, which means saving tens of hours of downtime per year.

3.2 Operation convenience brought by reduced regeneration frequency

Due to the reduced number of regenerations, engineers are more likely to synchronize regeneration operations with routine maintenance such as cavity baffle replacement or target material replacement, thereby further reducing overall downtime and achieving maintenance synergy.

3.3 No need for process revalidation

The manual emphasizes that the enhanced 8F has the same pumping speed for all gases as the standard On Board 8F and Cryo Torr 8F, so users do not need to re qualify the process after replacement, greatly reducing the risk and workload of replacement.

Performance parameters and regeneration time

4.1 Pumping speed and capacity

Parameter Value

Hydrogen pumping rate 2200 l/s

Air extraction speed 1500 l/s

Steam pumping speed 4000 l/s

Argon pumping speed 1200 l/s

Argon flux 700 SCCM (9 Torr-l/s)

Hydrogen capacity 12 standard liters (5 × 10 − 6 Torr)

Cross venting volume of 150 Torr-l

Nominal regeneration time (cold to cold) for the first and second stages, 2.5 hours

Only second level regeneration (fast regeneration mode)<1 hour

Note: The fast regeneration mode is suitable for sputtering processes and requires cooperation with the FastRegen control module.

4.2 Regeneration time optimization

Standard regeneration (cold to cold) takes 2.5 hours, but if only the second stage (mainly adsorbing argon and nitrogen) needs to be regenerated and equipped with a FastRegen control module, the time can be compressed to less than 1 hour. This provides greater flexibility for production scheduling.

Full compatibility with existing equipment

The enhanced On Board 8F is designed to remain fully compatible with all installed On Board 8F or Cryo Torr 8F process tools:

New equipment: can be directly integrated through factory installation.

Installed equipment: In fab retrofit can be carried out on-site in the wafer fab without the need to modify existing cavity interfaces, cooling water connections, or electrical control circuits.

This compatibility eliminates the need for users to replace existing valves, controllers, or pipelines, minimizing upgrade costs and time.

Reliability guarantee: GUTS global support network

All Edwards CTI Kryogenics products are covered by the GUTS (Guaranteed Uptime Support) program, a global rapid response service network that guarantees equipment uptime

24/7 technical support.

There are service centers in major regions around the world (Europe, America, Asia Pacific).

Promise immediate and professional response and action.

For semiconductor factories, rapid response is crucial in the event of pump failure or performance issues, and GUTS can ensure the shortest downtime for repair.

Engineering Integration and Selection Suggestions

7.1 When to Choose Enhanced On Board 8F

High load sputtering process: applications with frequent deposition of aluminum, titanium, titanium nitride, etc. have high regeneration frequency and significant upgrade benefits.

Pursuing maximum production capacity: Any manufacturer looking to improve tool utilization and reduce the cost per wafer.

Used On Board 8F or Cryo Torr 8F: can be seamlessly replaced without modifying existing facilities.

7.2 Replacement and Upgrade Process

Evaluate the current regeneration frequency and vacuum recovery curve to confirm the expected benefits of enhanced 8F.

Contact Edwards' local representative to obtain a retrofit kit or new pump order.

Complete pump replacement or modification within the scheduled maintenance window (usually within 1-2 hours, excluding regeneration time).

Restart the process, as there is no change in pumping speed, there is no need to re evaluate and production can be resumed immediately.

7.3 Maintenance Plan Optimization

By reducing the number of regenerations, regeneration operations can be scheduled on fixed maintenance days each month (such as target material replacement days) to avoid unplanned downtime. At the same time, consider adopting FastRegen mode to reduce downtime to within 1 hour when only the second level regeneration is required, further enhancing flexibility.

Quantitative analysis of actual returns

Assuming that an existing On Board 8F sputtering production line regenerates 6 times a month for 2.5 hours each time, it will shut down for 15 hours per month. If the enhanced 8F is used, the regeneration frequency is reduced to 2.5 times (reduced by 60%), and the downtime is about 6.25 hours, saving 8.75 hours per month. Based on the output of 20 wafers per machine per hour, an additional 175 wafers are produced per month. A factory with 10 devices can increase the production of thousands of wafers per month while reducing waste of target materials and energy.

Troubleshooting and Common Problems

The recovery time is still too long: check if the pump has reached saturation capacity, confirm if the process gas composition has changed, and perform complete regeneration if necessary.

Poor vacuum degree after regeneration: Ensure sufficient regeneration heating and release of all adsorbed gases; Check the sealing of the connection.

Incompatible with old controllers: The enhanced 8F uses standard interfaces, but if the controller firmware is too outdated, it may need to be upgraded; Suggest consulting Edwards support.

Fast regeneration failure: Confirm that the FastRegen control module has been correctly installed and activated, and is only applicable to the second level regeneration.