Low Cost Automation Tutorial

#111 Clean Room Compatible LCA - 2: Standard Structure of Clean Rooms

Category : Clean room technology

March30, 2012

(1) What is a clean room

A clean room is a room supplied with particle removed air filtered by high performance filters (HEPA filter, ULPA filter). The room air pressure is kept high (positive) to prevent infiltration of airborne particle contaminants.

(2) Types of clean rooms

There are following 3 types of clean rooms classified by air flow types (see [Fig.1])

Clean room type	Format	Characteristic
Unidirectional flow method	There are horizontal and vertical types	For high quality clean rooms
Non-unidirectional flow method	There are turbulence and replacement types	For LCA use in medium grade clean rooms
Combined method	Combination of a. and b.	Easy to obtain high "Cost vs. Performance"

[Fig.1 - a] Unidirectional flow clean room type

(3) About cleanliness localization

Cleanliness localization is a concept of keeping only the required localized space clean where especially high levels of contamination control within a clean room. Following two types are the main elements of cleanliness localization, and represent a concept of realizing clean environments where necessary as opposed to making the entire room clean.

Localized cleanliness structural elements	Format	Characteristic
Micro environment	Only the products (silicon wafers, etc.) are encapsulated and transferred to keep out contamination Sealed containers are SMIF, POD, FOUR, etc.	Corresponding to high quality contamination prevention
Mini environment	Contamination sensitive equipment and work areas are isolated with partition walls for contamination control Systemized with sealed containers (micro environments) to create localized cleanliness	Easy to achieve co-existence of clean environments and efficient production activities.

(4) Standard clean room example

[Fig.2] shows an example of a standard clean room. Clean rooms are design to administer proper contamination control for the work to be performed. The cleanliness is made to get higher from the entrance on. The layout is designed according to the types of work (work area, equipment area, maintenance area, passage way, preparation room, etc.).

[Fig. 2] Standard clean room layout

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