U.S. patent application number 12/110276 was filed with the patent office on 2009-02-12 for photomask pod, photomask transport pod and supporter thereof.
Invention is credited to Chien-Feng WANG.
Application Number | 20090038985 12/110276 |
Document ID | / |
Family ID | 40345465 |
Filed Date | 2009-02-12 |
United States Patent
Application |
20090038985 |
Kind Code |
A1 |
WANG; Chien-Feng |
February 12, 2009 |
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.
Inventors: |
WANG; Chien-Feng; (Shulin
City, TW) |
Correspondence
Address: |
SINORICA, LLC
528 FALLSGROVE DRIVE
ROCKVILLE
MD
20850
US
|
Family ID: |
40345465 |
Appl. No.: |
12/110276 |
Filed: |
April 25, 2008 |
Current U.S.
Class: |
206/710 |
Current CPC
Class: |
G03F 7/70825 20130101;
G03F 7/70741 20130101; H01L 21/67359 20130101; G03F 7/70858
20130101; H01L 21/67396 20130101 |
Class at
Publication: |
206/710 |
International
Class: |
B65D 85/00 20060101
B65D085/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 10, 2007 |
TW |
096213177 |
Claims
1. A photomask pod comprising: a first cover, and a second cover,
which is assembled to the first cover so as to enclose an inner
space for accommodating at lease one photomask; wherein at least
one of the first and second covers has a body with a plurality of
supporters or retainers at a surface facing the inner space, in
which the supporters or retainers are made of a static dissipative
material.
2. The photomask pod of claim 1 wherein the static dissipative
material has a surface resistivity ranging from about 10.sup.4 to
about 10.sup.11.OMEGA..
3. The photomask pod of claim 1 wherein the supporters and
retainers are made of different materials.
4. The photomask pod of claim 1 wherein the supporters and
retainers are made of an identical material.
5. The photomask pod of claim 1 wherein a conductive panel is
provided at the surface of the body facing the inner space, and the
supporters are deposited on the conductive panel and electrically
connect with the conductive panel.
6. The photomask pod of claim 1 wherein the first cover or the
second cover is made of metal.
7. The photomask pod of claim 1 wherein each of the supporters
comprises: a planar base connecting with a first inclined surface
that further connects with a second inclined surface so that the
planar base, the first inclined surface and the second inclined
surface form as the supporter integrally, and two first openings
are provided near both lateral sides of the supporter wherein each
of the first openings is equipped with an upper fastening piece and
a lower fastening piece.
8. The photomask pod of claim 1 wherein each of the supporters
comprises: a base, which affixes to each corners of the upper cover
of the photomask pod via a plurality of supporting points, and a
flexible bent component, having one end which connects to the base
and has an opposing end flexibly suspending between the plurality
of supporting points, which further comprises a propping surface
and a pressing surface; wherein when the photomask pod encloses a
photomask, the propping surface and the pressing surface of the
flexible bent component contact the photomask so as to fix it.
9. The photomask pod of claim 1 wherein the photomask pod can also
be a photomask transport pod.
10. A photomask pod comprising: a first cover, a second cover,
which is assembled to the first cover so as to enclose an inner
space for accommodating at least one photomask and at least one of
the first and second covers has a body, a plurality of retainers,
which is provided at a surface of the body facing the inner space,
and a plurality of supporters, which is provided at the surface of
the body facing the inner space and made of a static dissipative
material; wherein the plurality of retainers and the plurality of
supporters are formed by multi-component injection molding method
and then combined mutually.
11. The photomask pod of claim 10 wherein the static dissipative
material has a surface resistivity ranging from about 10.sup.4 to
about 10.sup.11.OMEGA..
12. The photomask pod of claim 10 wherein the photomask pod can
also be a photomask transport pod.
13. A supporter comprising: a planar base connecting with a first
inclined surface that further connects with a second inclined
surface so that the planar base, the first inclined surface, and
second inclined surface form as the supporter integrally, and two
first openings are provided near both lateral sides of the
supporter and each of the first openings is equipped with an upper
fastening piece and a lower fastening piece wherein the supporter
is partially or entirely made of a static dissipative material.
14. The supporter of claim 13 wherein the static dissipative
material has a surface resistivity ranging from about 10.sup.4 to
about 10.sup.11.OMEGA..
15. The supporter of claim 14 wherein the static dissipative
material is polyetheretherketone.
16. A supporter comprising: a base, which affixes to each corner of
an upper cover of a photomask pod via a plurality of supporting
points, and a flexible bent component, which has one end connecting
to the base and an opposing end flexibly suspending upon the
plurality of supporting points, which further comprises a propping
surface and a pressing surface; wherein when the photomask
transport pod encloses a photomask, the propping surface and the
pressing surface of the flexible bent component contact the
photomask so as to fix it, in which the supporter is partially or
entirely made of a static dissipative material.
17. The supporter of claim 16 wherein the static dissipative
material has a surface resistivity ranging from about 10.sup.4 to
about 10.sup.11.OMEGA..
18. The supporter of claim 17 wherein the static dissipative
material is polyetheretherketone.
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
silicon wafers is required with absolute cleanness. Thus, clean
rooms are typically employed in general wafer processes for
preventing particles in the air from defiling photomasks and
wafers. However, absolute dustless environment is inaccessible even
in known clean rooms. Hence, reticle pods that facilitate
preventing defilement are implemented in current semiconductor
processes for the purpose of storage and transportation of
photomasks so as to ensure cleanness of the photomasks.
[0005] Conventional photomask pods are generally made of
macromolecular materials, which possess the advantages of easy
forming, inexpensiveness and the ability to form transparency. Such
macromolecular materials, which are insulating and have high
surface resistivity, are liable to induce static due to friction
and separation. Especially, in the low-moisture environment of a
clean room, photomask pods made of such macromolecular materials
are apt to produce and accumulate charges thereon. 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.
[0006] Many solutions have been introduced to eliminate ESD. The
primary solution is to manage the operational environment with
proper atmospheric moisture. Clothes having grounding effects for
staff and ion fans may be also helpful to eliminate environmental
static. However, there are countless factors in the operational
environment, and it is actually impossible to completely protect
photomasks from being damaged by static.
[0007] An alternative solution is to change the material of the
components composing a photomask pod, as disclosed in U.S. Pat. No.
6,513,654, wherein a supporter having a grounding effect is
provided so that when the photomask pod contacts a corresponding
station, the supporter helps to conduct out charges on the
photomask. Furthermore, another solution, provided by U.S. Pat. No.
6,247,599, involves equipping a metal layer on a bottom plate, a
cover, or a handle of the photomask pod so as to reduce charge
accumulation. 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.
[0008] Therefore, the present invention provides novel supporters
or retainers to remedy the above defects of the prior arts.
SUMMARY OF THE INVENTION
[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.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The invention as well as a preferred mode of use, further
objectives and advantages thereof, will best be understood by
reference to the following detailed description of an illustrative
embodiment when read in conjunction with the accompanying drawings,
wherein
[0016] FIG. 1 is a schematic view of a photomask pod;
[0017] FIG. 2 illustrates a supporter and a retainer of the present
invention according to one preferred embodiment;
[0018] FIG. 3A to FIG. 3D illustrate a supporter of the present
invention according to one preferred embodiment;
[0019] FIG. 4 illustrates the supporter of the present
invention;
[0020] FIG. 5A and FIG. 5B illustrate a supporter of the present
invention according to another preferred embodiment;
[0021] FIG. 6 illustrates a supporter of the present invention
according to another preferable embodiment, and
[0022] FIG. 7 illustrates a supporter and a retainer of the present
invention according to another preferred embodiment.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0023] It is to be stated at first that essential components and
combining means among the components of the disclosed supporters
and retainers made of a static dissipative material in the present
invention are well known in the art and need not be discussed at
length herein. Meanwhile, the basic structure of photomasks pod and
the principle where photomask pods are based on are also well known
by those skilled in the art and need not be disclosed in the
present invention. Beside, the accompanying drawings are provided
for illustration and are not and need not to be drawn in scale.
[0024] FIG. 1 is provided for illustrating a photomask pod or a
photomask transport pod. Therein, the photomask pod or photomask
transport pod 100 comprises a first cover or a top cover 102 and a
second cover or a bottom plate 104. The first cover or top cover
102 and the second cover or bottom plate 104 can be assembled to
enclose an inner space for accommodating a photomask 114 therein.
The first cover 102 or the second cover 104 of the photomask pod or
photomask transport pod 100 may be made of metal. Alternatively, a
metal liner may be additionally equipped in the photomask pod or
photomask transport pod 100 to provide the shielding effect so as
to insulate an extrinsic interference. The second cover or bottom
plate 104 is composed of a body 106, a conductive panel 108, a
plurality of supporters 112 and a plurality of retainers 110. The
conductive panel 108 is arranged on a surface of the body 106
facing the inner space and is made of a conductive material. The
plural retainers 110 and supporters 112 are settled on the
conductive panel 108 while the retainers 110 and supporters 112 may
be made of different materials or made of an identical material.
The supporters 112 are electrically connected to the conductive
panel 108 and are made of a static dissipative material having a
surface resistivity ranging from about 10.sup.4 to about
10.sup.11.OMEGA.. When the photomask 114 is placed on the
supporters 112, the supporters 112 directly contact the photomask
114. The static dissipative material helps to continuously conduct
out charges so as to protect the photomask from being damaged by
high heat resulted from transient discharge. Since the charge
accumulation of the photomask is reduced, the photomask is
protected from being damaged by static.
[0025] FIG. 2 provides a preferable embodiment of the present
invention, showing a plurality of supporters or retainers deposited
in a photomask pod. A second cover 104 of the photomask pod 100
comprises of a body 106, a conductive panel 108, a photo mask 114,
a plurality of retainers 110 and a plurality of supporters 112. The
first cover 102 or the second cover 104 of the photomask pod 100
may be made of metal. Alternatively, a metal liner may be
additionally equipped in the photomask pod or photomask transport
pod 100 to provide the shielding effect so as to insulate an
extrinsic interference. The conductive panel 108 is settled on the
body 106 while the plural retainers 110 or supporters 112 are
provided on the conductive panel 108. Therein, the retainers 110
and supporters 112 are formed by multi-component injection molding
and then combined mutually. The supporters 112 are provided as
inserting pieces and are made of a static dissipative material
having a surface resistivity ranging from about 10.sup.4 to about
10.sup.11.OMEGA.. When being placed in the second cover 104 of the
photomask pod 100, the photomask 114 is supported by a retainer 110
as well as the plural supporters 112 and is retained on the second
cover 104 by the retainers 110. The retainers 110 surrounding the
photomask 114 function to reduce possible vibrations occurred in
transportation of the photomask pod 100 and for securing the
photomask 114 from impact. Hence, the plural retainers 110 and the
plural supporters 112 are provided to function collaboratively.
[0026] FIG. 3A provides another preferred embodiment of the plural
supporters in the photomask pod. Therein, a supporter 200 is
integrally formed and made of a static dissipative material having
a surface resistivity ranging from about 10.sup.4 to about
10.sup.11.OMEGA.. The supporter 200 comprises at least one planar
base 202 connecting with a first inclined surface 204 that is
further connected with a second inclined surface 206 so that the
planar base 202, the first inclined surface 204 and second inclined
surface 206 are formed as the supporter 200 integrally. It is to be
stated that the configuration of the first inclined surface 204 and
the second inclined surface 206 is not to be limited by the present
invention. Therein, the first inclined surface 204 is approximately
perpendicular to the planar base 202. However, the degree of the
angle between the first inclined surface 204 and the planar base
202 may vary in alternative embodiments. Another angle is also
formed by the second inclined surface 206 and the first inclined
surface 204 to provide a surface for smoothly guiding an article to
slide on the second inclined surface 206. Furthermore, two first
openings 208 are provided near both lateral sides of the supporter
200. Each of the first openings 208 is equipped with an upper
fastening piece 210 and a lower fastening piece 212. Thereby, when
a photomask 114 is placed in the bottom plate 104 of the photomask
transport pod 100 and then the top cover 102 is assembled to the
bottom plate 104, the second inclined surfaces 206 of the
supporters 200 helps the photomask 114 to be guided smoothly to a
proper position in the photomask transport pod 100 where the
photomask 114 can be steadily positioned. Then the upper fastening
pieces 210 and the lower fastening pieces 212 help to support and
fix the photomask 114.
[0027] In addition, FIG. 3A, FIGS. 3B, 3C and 3D provide one
embodiment of the supporters arranged in the photomask transport
pod. The embodiment shown in FIG. 3B is featured by a second
opening 214 additionally formed at a central portion of the
supporter 200. In different embodiments, this second opening 214
may be set at the central portion of the supporter 200 or
alternatively formed on the second inclined surface 206 with a
plurality of openings. This design of the second opening 214
diminishes a contact area between the photomask 114 and the
supporter 200 so as to reduce the generation of dust and particles.
FIG. 3C and FIG. 3D both represent another embodiment of the
supporter 200 of the present invention. The supporter 200 of the
present embodiment is characterized in that at least one guiding
track 216 is arranged near the central portion. Alternatively, two
guiding tracks 216 may be provided at two sides of said second
opening 214. On objective of the guiding track 216 is to further
diminish the contact area between the photomask 114 and the
supporter 200 when the photomask 114 contacts and slides on the
supporter 200 so as to increase the yield of the manufacturing
process. Besides, for fixing the supporter 200 in the top cover 102
of the photomask transport pod 100, a pair of connecting components
218 may be additionally provided at two peripheral portions of a
lower surface of the planar base 202 of the supporter 200, as shown
in FIG. 4. Thereby, the supporter 200 can be fixed at a side of the
top cover 102. The supporter 200 may be made of a static
dissipative material with a surface resistivity ranging from about
10.sup.4 to about 10.sup.11.OMEGA. or made of an elastic material.
The static dissipative material is polyetheretherketone.
[0028] FIGS. 5A, 5B and 6 provide one more embodiment of the plural
supporters in the photomask pod. Therein, a supporter 300 comprises
a base 302 and one or plural supporting points 304 arranged on the
base 302 so that the base 302 can be fixed at each corner of the
top cover 102 of the photomask transport pod 100. At the meantime,
a flexible bent component 306 is connected to the base 302, wherein
the flexible bent component 306 has one end integrally extending
from the base 302 and has an opposing end flexibly suspending upon
this or the plural supporting points 304. The flexible bent
component 306 further comprises a pressing surface 308 and a
propping surface 310 so that when the top cover 102 and bottom
plate 104 of the photomask transport pod 100 enclose the photomask
114, the pressing surface 308 and the propping surface 310 of the
flexible bent component 306 can contact and fix the photomask 114.
Additionally, this or the plural supporting points 304 may be
configured on the supporter 300 obliquely with an included angle
between each said supporting point 304 and the supporter 300. The
included angle may vary in different embodiments. In the present
embodiment, the plural supporting points 304 are employed for
example. Moreover, the supporter 300 is made of a static
dissipative material with a surface resistivity ranging from about
10.sup.4 to about 10.sup.11.OMEGA. and is detachably connected to
the top cover 102 of the photomask transport pod 100. The static
dissipative material is polyetheretherketone.
[0029] FIG. 7 illustrates one more embodiment of the plural
retainers or supporters provided in the photomask pod. Therein, a
photomask pod 100 comprises a first cover 102 and a second cover
104, which can be assembled to enclose an inner space to
accommodate a photomask 114. The first cover 102 or the second
cover 104 of the photomask pod or photomask transport pod 100 may
be made of metal. Alternatively, a metal liner may be additionally
equipped in the photomask pod or photomask transport pod 100 to
provide the shielding effect so as to insulate an extrinsic
interference. A plurality of supporters 112 in the photomask pod
100 may be provided in both the forms of the first supporter 112
and the third supporter 300. The first supporter 112 are arranged
on the second cover 104 and the third supporter 300 are deposited
on the first cover 102. A conductive panel 108 is arranged on a
body 106 of the second cover 104 and the plural retainers 110 or
the first supporter 112 are positioned on the conductive panel 108,
wherein the first supporter 112 are electrically connected to the
conductive panel 108. The retainers 110 and the first supporter 112
may be made of different materials or made of an identical
material. Therein, the retainers 110 and the first supporter 112
are formed by multi-component injection molding method and then
combined mutually. The first supporter 112 is provided as inserting
pieces and is made of a static dissipative material having a
surface resistivity ranging from about 10.sup.4 to about
10.sup.11.OMEGA.. The third supporter 300 comprises a base 302 and
one or plural supporting points 304 arranged thereon so that the
base 302 can be fixed at each corner of the top cover 102 of the
photomask pod 100. Meanwhile, a flexible bent component 306 is
connected to the base 302, wherein the flexible bent component 306
has one end integrally extending from the base 302 and has an
opposing end suspending upon the one or plural supporting points
304. Thereby, when placed in the second cover 104 of the photomask
pod 100, the photomask 114 is supported by the plural retainers 110
and the first supporter 112 and is fixed on the second cover 104 by
the retainers 110. The retainers 110 surrounding the photomask 114
function to reduce possible vibrations occurred in transportation
of the photomask pod 100 and to secure the photomask 114 to prevent
impact. Hence, the retainers 110 and the first supporter 112 are
provided to function collaboratively. When the first cover 102 and
the second cover 104 enclose the photomask 114, a flexible bent
component 306 of the third supporter 300 on the first cover 102
further comprises a pressing surface 308 and a propping surface 310
so that the pressing surface 308 and the propping surface 310 of
the flexible bent component 306 can contact the photomask 114 to
fix it and jointly support the photomask 114. Besides, since the
photomask 114 directly contacts with the first supporters 112 and
third supporter 300, to use the static dissipative material with a
surface resistivity ranging from about 10.sup.4 to about
10.sup.11.OMEGA. as the material of the supporters can continuously
conduct out charges so as to protect a photomask from being damaged
by high heat resulted from transient discharge and to reduce charge
accumulation and protect a photomask 114 from being damaged by
static.
[0030] One additional embodiment of the present invention is herein
provided for illustrating the plural retainers or supporters
settled in the photomask transport pod 100. Therein, a photomask
transport pod 100 comprises a top cover 102 and a bottom plate 104,
which can be assembled to enclose an inner space to accommodate a
photomask 114. The photomask transport pod 100 may be made of
metal. Alternatively, a metal liner may be settled in the photomask
transport pod 100 to provide the shielding effect so as to insulate
an extrinsic interference. A plurality of supporters 112 in the
photomask pod 100 may be provided in the forms of the first
supporter 112, the second supporter 200 and the third supporter
300. The first supporters 112 are arranged on the bottom plate 104
and the second supporters 200 as well as the third supporters 300
are deposited on the top cover 102. At four corners of the top
cover 102, the plural second supporters 200 or the third supporters
300 are provided and are detachably fastened to the corners of the
top cover 102 by the connecting components 218 or the one or plural
supporting points 304 of the base 302 thereof. The supporters 300
may be further equipped with a plurality of pressing surfaces 308
and propping surfaces 310 to fix and support the photomask 114.
When placed in the bottom plate 104 of the photomask transport pod
100, the photomask 114 is supported by the plural retainers 110 as
well as the first supporters 112 and is retained on the bottom
plate 104 by the retainers 110. When the top cover 102 is assembled
to the bottom plate 104, since the second supporters 200 are
provided at the opening of a reversed-U shaped structure of the top
cover 102 facing the bottom plate 104, the second inclined surfaces
206 of the second supporters 200 helps the photomask 114 to be
smoothly guided into the position of the reversed-U shaped
structure. Meanwhile, because the third supporter 300 are provided
at the corners of the top cover 102, after being guided by the
second inclined surfaces 206 of the second supporters 200 to the
proper position, the photomask 114 is further jointly supported and
fixed by the upper and lower fastening pieces 210 and 212 of the
second supporters 200 and the pressing and propping surfaces 308
and 310 on the flexible bent component 306 of the plural third
supporters 300. Besides, since the photomask 114 directly contact
with the first, the second and the third supporters 112, 200 and
300, the static dissipative material of these supporters with the
surface resistivity ranging from about 10.sup.4 to about
10.sup.11.OMEGA. helps to continuously conduct out charges so as to
protect the photomask from being damaged by high heat resulted from
transient discharge. Since charge accumulation is reduced, the
photomask is protected from being damaged by static.
[0031] All of the features disclosed in this specification may be
combined in any combination. Each feature disclosed in this
specification may be replaced by an alternative feature serving the
same, equivalent, or similar purpose. Thus, unless expressly stated
otherwise, each feature disclosed is only an example of a generic
series of equivalent or similar features.
[0032] From the above description, one skilled in the art can
easily ascertain the essential characteristics of the present
invention, and without departing from the spirit and scope thereof,
can make various changes and modifications of the invention to
adapt it to various usages and conditions. Thus, other embodiments
are also within the scope of the following claims.
* * * * *