-  VALTRIA IN NEWS  -

“Maximizing product quality and yield requires strict control and coordination between the manufacturing, facility, tooling, process and operation, but all of these heavily depend upon the strict environmental control afforded by advanced cleanroom technology.”

As in the previous research done by the Japanese, which was once presented at the ICCCS seminar in Paris in the 80s in order to achieve the above-mentioned goals, it was emphasized to consider three important factors:

• the suitability of the process equipment for a clean room
• cleanroom solution
• the way operators work in production facilities

In my very short article here, we will focus on topic, i.e. the necessary consideration by design of semiconductor production facilities and devices.
“As they say well planned is half done and this saying still holds true.”
 

A prerequisite for good planning are:

1. The customer's participation and commitment to good cooperation with the supplier.
    
2. A thorough discussion between customer and supplier about the starting points for the design. The "bible" of planning is the so-called Equipment Utility Matrix, which is for process equipment and the media that serve it. The better this document can be defined and locked, the planning, not to mention the implementation, will be easier, in order to avoid additional costs in the planning at the latest during the Basic Design, later in the implementation and unnecessary time delay.
    

The shape of layout with semiconductor production in mind:

There are in principle three different layout types in use in microelectronics construction for cleanroom`s:

• Service area Cleanroom
• Service area with chases
• Service area Cleanroom Mini environment

       
        a)  Ballroom
        b)  Service chase
        c)  Minienvironment - type

We recommend the service Chase solution with a three-layer solution by building.

Service Chase option

Three-level solution:

Basement/clean rooms/technical – machine room, either air conditioning machines placed in the basement or more commonly above the clean room in the so-called in the technical – machine room.

This three-level solution serves as best way devices serving the process, such as e.g. gas cabinets, pumps, chemical supply, etc. below the optimal placement cleanroom and enables clean room walls on 2 nd floor & FFU changes later easily by process- equipment locations change. Extensions, when it comes to the question and cost-optimal placement of air condition units in the clean room above on the 3rd floor, where the supply-, circulation- and the distances of the exhaust- air ducts remain small.
 

Following items to be taken in consideration:

1. Connections to process equipment`s (power, volumes, POU`s, pressure and quality level, etc.)
2. Thermal loads, molecular contaminations, electromagnetic interference and vibration (criterion curves VC) - of process equipment`s, (lithography, wafer bonding, SEM, characterization areas)
3. Number of employees, room classes, air changes (energy saving aspect), °C, RH, pressure in rooms and their tolerances
4. Exhaust air quantities of process equipment (type of exhaust air, e.g. general removal, solvents, corrosive substances, toxic gases, vacuum pumps, etc.)
5. Removal of chemicals (substances going from wet benches to containers, neutralization plant + possible waste treatment plant, depending on the chemicals used
6. Gas qualities (need of possible scrubbers)
7. Gas detectors (mobile/fixed detectors)
8. Compressed air (dew point – 70 °C/- 40 °C, network pressure) & vacuum
9. Electricity (UPS like for toxic exhaust scrubbers, sensors, alarm and security systems
10. BMS & monitoring control & fire alarm system
11. DI – water
12. Central vacuum system
13. How to prepare for possible future expansions, expansion directions and flexibility of cleanroom constructions, which reservations should be taken into account already at this stage in the volume estimation of regions and media

The above questions have a significant impact on planning, not to mention future investment cost`s.
Other concepts have been alluded to, but for lack of space, not detailed here.
There are many concepts and many variations of each. Clear thinking and sound judgement are the only way to chose them.

Author:
Esa Högel - Valtria Swiss
Regional Director for Business Development in Germany, Scandinavia and Switzerland 
B.Sc. Economics, B.Sc. Process Engineer, EUR.ING (FEANI)