Terms used in this subpart are defined in the Clean Air Act, in §§63.2 and 63.981, the General Provisions of this part (40 CFR part 63, subpart A), and in this section as follows:

Combined HAP process vent means a process vent that emits both inorganic and organic HAP to the atmosphere.

Control device means a combustion device, recovery device, recapture device, or any combination of these devices used for the primary purpose of reducing emissions to comply with this subpart. Devices that are inherent to a process or are integral to the operation of a process are not considered control devices for the purposes of this subpart, even though these devices may have the secondary effect of reducing emissions.

Inorganic HAP process vent means a process vent that emits only inorganic HAP to the atmosphere.

Organic HAP process vent means a process vent that emits only organic HAP to the atmosphere.

Process vent means the point at which HAP emissions are released to the atmosphere from a semiconductor manufacturing process unit or storage tank by means of a stack, chimney, vent, or other functionally equivalent opening. The HAP emission points originating from wastewater treatment equipment, other than storage tanks, are not considered to be a process vent, unless the wastewater treatment equipment emission points are connected to a common vent or exhaust plenum with other process vents.

Semiconductor manufacturing means the collection of semiconductor manufacturing process units used to manufacture p-type and n-type semiconductors or active solid state devices from a wafer substrate, including processing from crystal growth through wafer fabrication, and testing and assembly. Examples of semiconductor or related solid state devices include semiconductor diodes, semiconductor stacks, rectifiers, integrated circuits, and transistors.

Semiconductor manufacturing process unit means the collection of equipment used to carry out a discrete operation in the semiconductor manufacturing process. These operations include, but are not limited to, crystal growing; solvent stations used to prepare and clean materials for subsequent processing or for parts cleaning; wet chemical stations used for cleaning (other than solvent cleaning); photoresist application, developing, and stripping; etching; gaseous operation stations used for stripping, cleaning, doping, etching, and layering; separation; encapsulation; and testing. Research and development operations associated with semiconductor manufacturing and conducted at a semiconductor manufacturing facility are considered to be semiconductor manufacturing process units.

Storage tank means a stationary unit that is constructed primarily from nonearthen materials (such as wood, concrete, steel, fiberglass, or plastic) which provides structural support and is designed to hold an accumulation of liquids or other materials used in or generated by a semiconductor manufacturing process unit. The following are not storage tanks for the purposes of this subpart:

(1) Tanks permanently attached to motor vehicles such as trucks, railcars, barges, or ships;

(2) Flow-through tanks where wastewater undergoes treatment (such as pH adjustment) before discharge, and are not used to accumulate wastewater;

(3) Bottoms receiver tanks; and

(4) Surge control tanks.

[68 FR 27925, May 22, 2003, as amended at 73 FR 42532, 73 FR 42532, July 22, 2008]