Case study: ToFSIMS benefits to a Semiconductor laboratory
Target: Non-Technical upper management and Lab managers
All subject matter is hypothetical and not meant to reflect any Company, production environment, or current products in the marketplace.
Real-Time Problem Solving has saved Semiconductor Company millions through reliable, fast, ToFSIMS Analysis.
BACKGROUND
ABC Inc. is a European Top 10 Semiconductor manufacturer, creating some of the most sophisticated integrated circuits (chips) for the automotive, military, servers, and now the new Internet of things and 5G markets. Established in 1982 in the UK, ABC Inc. has grown with employees of over 50,000 worldwide. Part of their superiority is its world-class production yields. High yields mean lower overall costs for the company. One of the reasons their returns are so high is their Materials and Failure Analysis labs that are using innovative technology, as they support semiconductor processes down to 7nm and beyond.
THE CHALLENGE
A few years ago, ABC Inc. labs found themselves challenged beyond their capabilities. “We found that our ability to measure thin films was becoming more and more difficult.” Said Andrew Steadman, lab manager. “We had fantastic techniques in-house such as Dynamic Secondary Ion Spectrometry (DSIMS), X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy on the chemistry side. For the imaging side, we had Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and Transmission Electron Microscopy (TEM). However, although we could see these thin films of a few monolayers with TEM, we could not get the right chemistry from them.”
As discussions developed with process and production departments, issues started to arise in the immediate chemistry of the interface between one layer and another. DSIMS could not show the interface contamination because the data was lost in the noise. Thin-film experimentation with XPS and Auger showed that there was an interface effect but could not determine the chemistry at the root of the problem because detection limits were not low enough. Of course, using multiple ‘short loop’ experiments fixed the issues, but the time started to increase exponentially.
A list of criteria for a new capability within the lab became longer:
- Tight sample-to-sample variation for high dose, shallow implantation better or equal to DSIMS
- The detection of ultra-thin-film concentrations, with high levels of repeatability
- An understanding of thin-film dopant concentration for both organic and inorganic films
- The ability to determine chemistry from interfaces of a few monolayers with increased detection limits
- Automation that allows these measurements to run without extra headcount.
THE SOLUTION
By 2000 the lab had started using a new technique called Time of Flight SIMS (ToFSIMS) from both European Universities and a laboratory in the USA. Unfortunately, turn around was not as fast as needed by the production department. A machine down in the factory limits the throughput of the product in the line. Steadman said, “It was around this time that we decided that we needed an onsite solution. We had discussions with the senior management, and of course, they saw the long-term gain if the price was right”.
Finally, after much discussion with all the available vendors and initial testing, the final review was between two vendors. The test pieces sent out were high dose shallow implants, thin films with dopant profiles, and surface and interface contamination samples. The team reviewed results from the set tests, automation indicators, and a check on the repeatability of sample-to-sample variation over several weeks, as well as each of the vendor’s machine performance.
“After extensive testing, we gave the order to Materials Corporation, and we took delivery in 2001. Since then, the tool has completed thousands of hours and saved ABC Inc. millions in potential lost revenue.” Said a delighted Steadman.
Two companies were quickly ahead of the competition. Although both systems performed the standard tests excellently and beyond the expectations, the following three points differentiated Materials Corporation Tool…
- The standard deviation in the thin-film analysis was much tighter.
- Defect mapping was straightforward.
- Reliability of the system during testing showed Materials Corporation’s equipment to be more reliable.
THE RESULTS
Real-Time Problem-Solving.
In a production environment, it is essential to get results back to the production engineers so they can initiate a solution as soon as possible. When factory toolsets gave issues, ABC Inc. found sending samples to labs in the US or Europe could take between three and seven days to get results back. Having a production line limp along reduces the cost-effectiveness in a manufacturing environment. With the ToFSIMS system in-house, they were able to get results back to their engineers sometimes on the same day.
In Steadman’s words, “This time saving is hard to put into monetary terms. However, in some recent cases, we were lines down, and we were working on the tool immediately with samples from the FAB (Fabrication factory). They had the required data to get the line back up and running again that evening. We couldn’t do that before.”
The Sample to Sample Variation Less Than 0.5%
ABC Inc. noticed after six months, the high dose shallow implant sample-to-sample variation did not waiver and kept within the tight 2% tolerance. What was more impressive, the original short-term goal (within-day range) of 1% was able to be extended to within month!
Ultra-thin film standard concentrations repeatability over a 6-month window is down to 2.35%. Such tight variation for doped thin films has allowed automating experiments overnight, which does not need an increase in headcount; previously, DSIMS had to be run manually to keep the range at the less than 3% goal for the same sample set.
The ability to keep the matching criteria down to the 0.5% day-to-day enabled ABC Inc. to perform more and more complex testing for the factory. This improved ability allowed their implant team much more reliable data, which helped tune their implanters to be more precise and enable standard deviations to be improved.
Increased Functionality
The ToFSIMS detection limits of 1-10’s of parts per million (ppm), has a considerable advantage over techniques such as Auger and XPS that are in the region of 1000 ppm or worse! The enhanced detection limits and the vertical resolution enabled ABC Inc.’s lab to understand the chemistry at both the surface and interface and allowing their customers the ability to understand monolayer contamination levels consistently.
Service Excellence
Working with the Materials Corporation service team was one of those unexpected highlights. Materials Corporation quickly became a ‘vendor of choice’ as their service team not only worked around ABC Inc.’s IP restrictions but also made every effort to improve the quality and performance of the tool.
An example was that they taught the operators to perform essential service functions. That training saved both the companies money. The added advantage was that it increased tool UPTIME goals to above 95% for the year.
For example, Materials Corporation ships parts to the Senior Science engineer at ABC Inc., and she was able to perform first-pass checking the next day. Doing this allowed the lab to be able to support the factory or have a much better idea of the problem at hand. If required, a service engineer would fly over the next morning with the correct items and fix the system.
Indeed, Materials Corporation won vendor of the year for the whole factory, and this is a prestigious award. Consider the fact that Materials Corporation competition was large corporate enterprises with tens of multimillion-dollar toolsets in all FABs makes the award even more impressive.
Automation
“Over the next few years, a greater amount of automation was required. Materials Corporation realised that we were not the only people asking for more automation. So, they increased the headcount of the software department by 30%”. This willingness to increase their headcount showed they were strategically aware of their customer’s needs and acted decisively.
“The upgraded automation has been crucial for our ability to support the FAB at higher productivity rates,” continued Steadman.
Real-Time Improvement
As ABC Inc. records show, the results for lab tool, output and repeatability have been extraordinary. Average throughput time for the ToFSIMS results reduced by over 24%, while the sample count average increased by over 350% in the first three years of operation!
There was an added benefit that was not expected; during this timeframe ‘UP TIME’ of the tool increased from 90.3% to 96.8%. This increase was possible because of a combination of new internal automation and the service department’s strategic replacement program of consumable parts as well as some decisive redesign of existing components.
The enhanced components, strategic replacement program, and the upgraded automation package that comes free as a part of a full-service agreement meant that the ToFSIMS tool can now run overnight, reliably without any input.
“These guys are always looking for feedback,” Steadman said. “They are always trying to upgrade things. That improvement mentality has allowed us to push the system and enable us to do more with it.”
CONTACT INFORMATION
To learn more about how ToFSIMS can help your business understand those surface, interface and thin-film challenges, visit us at www.MaterialsCorporation.com or call 0044 123 456 7890
*Pull out quote
“I’m not a financial guy, but having the production line back up, sometimes 7x quicker is a cost-saving of enormous proportions!” Andrew Steadman ABC Inc. lab manager.
*Side Bar on Front Sheet
ABC Inc.
- European Top 10 Semiconductor manufacturer
- Specialises in integrated circuit manufacturing
- Implemented the ToFSIMS technique in 2001
- Throughput for analysis reduced by up to 7 times
- Sample count increased by over 350%
- With a tool availability over 96%