Photomask pod, photomask transport pod and supporter thereof

Abstract

A photomask pod and a photomask transport pod are provided for preventing particles in the environment from defiling a photomask as well as charge accumulation on the photomask from causing ESD damage. The photomask pod comprises two covers and the supporters or retainers on at least one of the two covers are made of a static dissipative material, which facilitates reducing charge accumulation and protecting the photomask from ESD damage.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to photomask pods and photomask transport pods and, more particularly, to a photomask pod and a photomask transport pod which can prevent damage caused by ESD.[0003]2. Description of the Related Art[0004]In the rapidly developing semiconductor technology, optical lithography plays an important role and wherever pattern definition is conducted, optical lithography is requisite. As to the application of optical lithography relating to semiconductors, a designed circuit pattern is used to produce a light-transparent photomask. Based on the principle of exposure, after a light passes through the photomask to be projected on a silicon wafer, the circuit pattern formed on the photomask can be exposed onto the silicon wafer. Since any dust (such as particles, powders or an organic material) can adversely affect the quality of such projected pattern, the photomask used to produce the pattern on the...

AI Technical Summary

Benefits of technology

[0009]To overcome the aforementioned defects of the prior arts, the present invention provides a photomask pod which has supporters or retainers made of a particular material. In the present invention, the supporters or retainers are made of a static dissipative material so that even when charges are generated on the static dissipative material because of friction, an adjacent metal material can instantly conduct out the charges so as to eliminate charge accumulation and ESD.

[0010]It is one objective of the present invention to provide a supporter of a mask, which is made of a static dissipative material to reduce charge accumulation and to protect a photomask from being damaged by static.

[0011]It is another objective of the present invention to provide a supporter of a photomask, which is made of a static dissipative material to continuously conduct out charges so as to protect a photomask from being damaged by high heat resulted from transient discharge.

[0012]It is another objective of the present invention to provide a retainer of photomask, which is made of a static dissipative material to reduce charge accumulation and to protect a photomask from being damaged by static.

[0013]It is another objective of the present invention to provide a retainer of a photomask, which is made of a static dissipative material to continuously conduct out charges so as to protect a photomask from being damaged by high heat resulted from transient discharge.

[0014]The present invention discloses a photomask pod and a photomask transport pod with supporters and retainers which directly contact a photomask and are made of a static dissipative material so as to provide a way for dissipating static. The static dissipative material has a property between conductive and non-conductive. Since the static dissipative material features a slow conductive velocity, discharge is not liable to happen between the supporters or the retainers and the photomask or the photomask pod. Consequently, the photomask can be free from the influence of heat generated by discharge so that the present invention provides superior protection to the photomask while shielding is also presented. As a result, the photomask is protected from the risk of being damaged.

Problems solved by technology

However, absolute dustless environment is inaccessible even in known clean rooms.

Such macromolecular materials, which are insulating and have high surface resistivity, are liable to induce static due to friction and separation.

Additionally, when a photomask is placed in or taken out from a photomask pod, static may easily occur on the surface of the photomask owing to friction.

Static on the photomask is attractive to particles in the air and may, even worse, cause electrostatic discharge (ESD) on metal wires of the photomask.

Transient currents induced by ESD can bring sparks or arcs that come along with powerful currents and high heat.

As such powerful currents and high heat oxidize and melt the metal wires of the photomask, the pattern on the photomask is consequently deformed.

However, there are countless factors in the operational environment, and it is actually impossible to completely protect photomasks from being damaged by static.

While all the aforementioned solutions are dependent on grounded electrically conductive components to release charges, it is to be noted that when static is released by such electrically conductive components, currents are unavoidably generated and discharge can still occur to damage the photomask.

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