1. Leakchecking Software: This answer is aimed at the “Standard” level of software, for example “TWARE32” or “RGA for Windows” , not the automation software like Fabguard. With this level of software the RGA file can be synchronized with the start of the process, and the timing can be offset by a fixed time.
2. Automation Software: This answer is aimed at the more sophisticated automation software, for example Fabguard .
In Situ Host is an alternative. It utilizes standard RGA hardware (compatible with most RGA manufacturers), and combines the “leakchecking” software with an automation module, such that sophisticated use of the instrument is possible, without overcomplicating the system.
Since In Situ Host retains the leakchecking software, the use of the RGA for maintenance activities is not compromised. Very often, the alternative automation packages result in a significant obstacle for the routine user.
When making any decision, it is useful to review what has worked for other customers. The best cases of RGA automation can be found at IBM, where the customer did not rely on the RGA vendor, but became very much self-sufficient. There are a number of companies that have attempted RGA automation by reliance on the RGA vendor. There are few success stories. The RGA hardware companies historically have done a good job with the hardware component, but a poor job of integration.
In Situ Host provides the tools necessary to automate the RGA without overcomplicating the system.
If one wants to automate any system, the objective is to numerically detect faults with a method consistent with process control that leads to their diagnosis and elimination. The raw data from the RGA is generally unsuitable for this function. Instead of a stream of numbers over time for a signal, a single number representative of a certain response during a certain interval is tracked.
Since In Situ Host does not communicate with the tool via the SECS port, Lot, Recipe, and Wafer ID are not automatically included in the data file. However, it was comprehended early in the development of the product that many customers would require this function. The product includes fields in both the data file and in the summary file for the inclusion of this information (3 ASCII strings per run). A demonstration program, complete with source code (VB6) is included on the In Situ Host installation disk.
The design of In Situ Host assumes that it will be a module included in a larger system. Alternative RGA automation systems assume that the RGA system will be the final home of data analysis. Most fabs have sophisticated tools for data analysis included in their factory automation system. In Situ Host makes the data, including the summary data, easily accessible such that it can be utilized in macroscopic factory analysis.
Can I use my open source RGA on my transfer chamber?
It will depend on the operating pressure of the transfer
chamber. Most open source RGA instruments
require a maximum operating pressure of about
1 E-4 torr or less to prevent damage to the hardware. If your system has infrequent excursions marginally above this level, then your system may still be a candidate. In order for this application to function well, the state of each of the slitvalves must be included in the RGA algorithm so that the system can assign the data to the associated chamber.
There is a strong time dependency of the degas process. Highly volatile solvents evolve primarily in the early stages of the degas process. In addition, on the most common degas reactor (200 mm Endura), there are multiple excursions caused by the loadlock door and the cooldown chamber door that need to be accommodated. Most customers find best results by concentrating on the time period late in the degas process.
The first factor is almost always operating pressure. One can reduce the sample pressure, but only be adding significant complexity and cost. The second important factor is chemistry. Some process chemistries can result in significant degradation of the instrument.