U.S. patent application number 10/592043 was filed with the patent office on 2007-08-16 for substrate storage container.
Invention is credited to Takayuki Nakayama, Junya Toda.
Application Number | 20070187287 10/592043 |
Document ID | / |
Family ID | 34975655 |
Filed Date | 2007-08-16 |
United States Patent
Application |
20070187287 |
Kind Code |
A1 |
Toda; Junya ; et
al. |
August 16, 2007 |
Substrate storage container
Abstract
A substrate storage container is provided which can convey, fix
and store substrates safely, with threaded members not being
loosened by a load applied to a mounting member of the substrate
storage container when the container storing substrates is conveyed
or when the container is fixed to a substrate processing apparatus
and by a heating process at the time of washing and drying of the
container. For fastening the mounting member (6), such as a side
plate for conveyance, a bottom plate for positioning the container
with respect to a substrate processing apparatus, etc., to the
substrate storage container including a container body (1) and a
lid (2) by threaded members (3), a locking means for preventing
loosening of the threaded members (3) is interposed between
engagement surfaces of each threaded member (3) and the mounting
member (6).
Inventors: |
Toda; Junya; (Tokyo, JP)
; Nakayama; Takayuki; (Tokyo, JP) |
Correspondence
Address: |
SNELL & WILMER LLP (OC)
600 ANTON BOULEVARD
SUITE 1400
COSTA MESA
CA
92626
US
|
Family ID: |
34975655 |
Appl. No.: |
10/592043 |
Filed: |
March 9, 2005 |
PCT Filed: |
March 9, 2005 |
PCT NO: |
PCT/JP05/04095 |
371 Date: |
September 8, 2006 |
Current U.S.
Class: |
206/711 |
Current CPC
Class: |
F16B 39/282 20130101;
H01L 21/67386 20130101; F16B 39/24 20130101; F16B 35/06
20130101 |
Class at
Publication: |
206/711 |
International
Class: |
B65D 85/00 20060101
B65D085/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 12, 2004 |
JP |
2004-070470 |
Claims
1. A substrate storage container comprising a container body, a
lid, a mounting member attached to the container body or the lid,
and a threaded member fixing the mounting member to the container
body or the lid, the mounting member and the threaded member
including respective surfaces cooperating with each other when the
mounting member is fixed to the container body or the lid by the
threaded member, characterized in that: a locking means for
preventing loosening of the threaded member is interposed between
said surfaces of the threaded member and the mounting member.
2. The substrate storage container according to claim 1, wherein
the locking means includes a projection provided on one of said
surfaces of the threaded member and the mounting member and a
recess provided on the other one of said surfaces so as to engage
with the projection.
3. The substrate storage container according to claim 1, wherein
the locking means includes a projection provided on one of said
surfaces of the threaded member and the mounting member and a
recess provided on the other one of said surfaces, wherein the
locking means includes a washer interposed between said surfaces of
the mounting member and the threaded member, wherein the washer
includes contact surfaces each being in contact with a respective
one of said surfaces of the mounting member and the threaded
member, and wherein the washer is provided on at least one of the
contact surfaces thereof with a protrusion engaging with the recess
provided on the other one of said surfaces of the threaded member
and the mounting member.
4. The substrate storage container according to claim 2, wherein
the recess includes inner side surfaces formed asymmetrically
relative to a rotation direction of the threaded member, and
wherein one of the inner side surfaces abuts against the projection
in the case of the rotation of the threaded member in a loosening
direction, to thereby prevent the rotation of the threaded
member.
5. The substrate storage container according to claim 3, wherein
the recess includes inner side surfaces formed asymmetrically
relative to a rotation direction of the threaded member, and
wherein one of the inner side surfaces abuts against the protrusion
of the washer in the case of the rotation of the threaded member in
a loosening direction, to thereby prevent the rotation of the
threaded member.
6. The substrate storage container according to claim 4, wherein
both of the inner side surfaces of the recess are formed as
inclined surfaces, and wherein the inclination of the one inner
side surface is greater than that of the other inner side
surface.
7. The substrate storage container according to claim 5, wherein
both of the inner side surfaces of the recess are formed as
inclined surfaces, and wherein the inclination of the one inner
side surface is greater than that of the other inner side
surface.
8. The substrate storage container according to claim 3, wherein
the washer is provided on the other contact surface thereof with a
second recess engaging with the projection provided on the one of
said surfaces of the threaded member and the mounting member.
9. The substrate storage container according to claim 3, wherein
the washer is provided on the other contact surface thereof with a
second protrusion engaging with the projection provided on the one
of said surfaces of the threaded member and the mounting
member.
10. The substrate storage container according to claim 5, wherein
the protrusion of the washer is formed to be a semicircular shape
in cross section, wherein one of the inner side surfaces of the
recess is formed as a circular arc surface having a cross-sectional
shape which meshes with the semicircular cross section of the
protrusion, and the other of the inner side surfaces is formed as a
gently inclined surface.
11. The substrate storage container according to claim 6, wherein
the inclination of the one inner side surface is 70.degree. to
90.degree. and the inclination of the other inner side surface is
10.degree. to 30.degree..
12. The substrate storage container according to claim 7, wherein
the inclination of the one inner side surface is 70.degree. to
90.degree. and the inclination of the other inner side surface is
10.degree. to 30.degree..
13. The substrate storage container according to claim 1, wherein
when an initial torque is measured by fastening the threaded member
to the container body or the lid with a predetermined torque and
measuring a torque at the time of loosening the threaded member and
when a torque is measured at the time of loosening the threaded
member after performing 50 times a heat cycle constituted of:
maintaining the substrate storage container at a normal temperature
of 20.degree. C. for 20 minutes; increasing the temperature to
100.degree. C. in 40 minutes; maintaining the temperature at
100.degree. C. for 30 minutes; and gradually reducing the
temperature to the normal temperature in 50 minutes, a ratio of the
difference between the initial torque and the torque after the heat
cycles to the initial torque is within .+-.20% of the initial
torque.
Description
TECHNICAL FIELD
[0001] The present invention relates generally to a substrate
storage container that stores substrates, such as semiconductor
wafers made of silicon, mask glass plates made of glass, etc., for
transport between plants and for conveyance or storage in process
steps, and more particularly, to a substrate storage container with
a locking means of a mounting member attached to the substrate
storage container.
BACKGROUND ART
[0002] In recent years, miniaturization of semiconductor components
and reduction in wiring pitch have been increasingly progressing. A
substrate storage container is fabricated to have a high sealing
property and is handled in an automated manner to eliminate
contamination due to human activity so as not to contaminate stored
substrates.
[0003] In response to such a tendency of the industry, a substrate
storage container disclosed in Japanese Patent Application
Laid-Open Publication No. 2000-306988 has been proposed, which
stores semiconductor wafers inside for conveyance and storage in a
production plant of semi-conductor components.
[0004] As shown in FIG. 1, such a substrate storage container is
basically constituted by a container body 1 provided with an
opening at the front thereof and including support portions 9
provided on opposed side wall surfaces thereof to support a
plurality of substrates at certain intervals within the container,
a lid 2 that closes the opening, and a seal member 11 interposed
between the container body 1 and the lid 2.
[0005] A top surface of the container body 1 has attached thereto a
robotic flange 4 for overhead conveyance of the substrate storage
container, and opposite outer side walls of the container body 1
have attached thereto a pair of manual handles 5 necessary for
conveyance of the substrate storage container, a pair of side rails
6, etc., using threaded members 3. On a bottom surface of the
container body 1, a bottom plate 8 is attached to a fixing portion
(not shown) provided on the bottom of the container body 1 by the
threaded members 3, which bottom plate 8 includes positioning
members 7 for positioning and fixing the substrate storage
container precisely to a substrate processing apparatus.
[0006] The plant in which the substrate storage containers are used
employs a mini-environment production system and includes a highly
cleaned interior space demarcated from the exterior space, wherein
a plurality of substrate processing apparatuses are disposed in the
interior space to perform various processes with respect to the
substrates.
[0007] The substrate storage container is docked with such a
substrate processing apparatus through positioning members 7, and
thereafter an opening/closing operation is performed with latch
mechanisms 10 disposed within the lid 2 to remove the lid 2 from
the container body 1. Thus, a substrate is taken out from the
opening and is supplied to the substrate processing apparatus.
After the process is completed, the substrate is inserted into the
substrate storage container again, and the lid 2 is mounted to the
container body 1, followed by locking with the latch mechanisms 10
to close the opening. Then, the substrate storage container is
automatically conveyed to the next process step. By repeating such
operations, a semiconductor chip is formed on the surface of the
substrate.
DISCLOSURE OF THE INVENTION
Problem to be Solved by the Invention
[0008] At each time of automated conveyance as described above, the
substrate storage container is conveyed to the next process step
while the automatic conveyance apparatus grips, supports and fixes
the mounting members for conveyance, which are attached to the
substrate storage container, to thereby perform processing.
[0009] Since the number of steps reaches 600 in production of
semiconductor components, the conveyance frequency of the substrate
storage container is increased considerably. Since such conveyance
is performed at high speed to increase the number of cycles and a
weight of the container storing substrates is as heavy as about 8
kg, a remarkable load is applied to the mounting members for
conveyance at each time of conveyance.
[0010] In order to maintain cleanliness in the container, a washing
process is performed periodically for the substrate storage
container, and after water drops adhering to the substrate storage
container are removed thoroughly in a subsequent drying step, the
substrate storage container is reused.
[0011] At the drying step, since the substrate storage container is
dried and processed at a high temperature of about 90.degree. C.,
the container itself is expanded and contracted by heating and the
threaded members 3 fixing the mounting members to the substrate
storage container may loosen.
[0012] The present invention has been made to solve the above
problems. Accordingly, an object of the present invention is to
provide a substrate storage container which can convey, fix and
store substrates safely, and which ensures threaded members fixing
a mounting member are not loosened by a load applied to the
mounting member of the substrate storage container and by a heating
process at the time of washing and drying the substrate storage
container when the substrate storage container stores and conveys
the substrate and when the substrate storage container is fixed to
the substrate processing apparatus.
Means for Solving Problem
[0013] According to the present invention, a substrate storage
container comprises a container body, a lid, a mounting member
attached to the container body or the lid, and a threaded member
fixing the mounting member to the container body or the lid, the
mounting member and the threaded member including respective
surfaces cooperating with each other when the mounting member is
fixed to the container body or the lid by the threaded member, and
the substrate storage container is characterized in that: a locking
means for preventing loosening of the threaded member is interposed
between said surfaces of the threaded member and the mounting
member.
[0014] The locking means preferably includes a projection provided
on one of said surfaces of the threaded member and the mounting
member and a recess provided on the other one of said surfaces so
as to engage with the projection.
[0015] The locking means may include a washer interposed between
said surfaces of the mounting member and the threaded member,
wherein the washer includes contact surfaces each being in contact
with a respective one of said surfaces of the mounting member and
the threaded member, and wherein the washer is provided on at least
one of the contact surfaces thereof with a protrusion engaging with
the recess provided on the other one of said surfaces of the
threaded member and the mounting member.
[0016] The recess may include inner side surfaces formed
asymmetrically relative to a rotation direction of the threaded
member, wherein one of the inner side surfaces abuts against the
projection provided on the one of said surfaces of the threaded
member and the mounting member or abuts against the protrusion of
the washer in the case of the rotation of the threaded member in a
loosening direction, to thereby prevent the rotation of the
threaded member.
[0017] In this case, both of the inner side surfaces of the recess
are preferably formed as inclined surfaces and the inclination of
the one inner side surface is preferably greater than the
inclination of the other inner side surface. In this case, the
inclination of the one inner side surface is preferably 70.degree.
to 90.degree. and the inclination of the other inner side surface
is preferably 10.degree. to 30.degree..
[0018] The washer may be provided on the other contact surface
thereof with a second recess or second protrusion engaging with the
projection provided on the one of said surfaces of the threaded
member and the mounting member.
[0019] The protrusion of the washer is preferably formed to be a
semicircular shape in cross section, wherein one of the inner side
surfaces of the recess is formed as a circular arc surface having a
cross-sectional shape which meshes with the semicircular cross
section of the protrusion, and the other of the inner side surfaces
is formed as a gently inclined surface.
[0020] Preferably, when an initial torque is measured by fastening
the threaded member to the container body or the lid with a
predetermined torque and measuring a torque at the time of
loosening the threaded member and when a torque is measured at the
time of loosening the threaded member after performing 50 times a
heat cycle constituted of: maintaining the substrate storage
container at a normal temperature of 20.degree. C. for 20 minutes;
increasing the temperature to 100.degree. C. in 40 minutes;
maintaining the temperature at 100.degree. C. for 30 minutes; and
gradually reducing the temperature to the normal temperature in 50
minutes, a ratio of the difference between the initial torque and
the torque after the heat cycles to the initial torque is within
.+-.20% of the initial torque.
EFFECT OF THE INVENTION
[0021] The substrate storage container of the present invention can
convey, fix and store substrates safely since a locking means is
arranged on the threaded member used for fixing to the substrate
storage container a mounting member such as a side plate for
conveyance or a bottom plate for positioning to the substrate
process apparatus, and the threaded member is not loosened by a
load applied to the mounting member of the substrate storage
container each time the stored substrate is conveyed and fixed to a
substrate processing apparatus and by a heating process at the time
of washing and drying the substrate storage container.
BRIEF DESCRIPTION OF DRAWINGS
[0022] FIG. 1 is an exploded perspective view showing one
embodiment of a substrate storage container according to the
present invention.
[0023] FIG. 2 is a perspective view showing an example of a side
rail in the one embodiment of the present invention.
[0024] FIG. 3 is a side view of the side rail of FIG. 2.
[0025] FIG. 4 is a partially enlarged perspective view showing a
portion of the side rail of FIG. 2 to be fixed to a container
body.
[0026] FIG. 5 is a front view of an example of a threaded member
used in the one embodiment of the present invention.
[0027] FIG. 6 is a plan view of the threaded member of FIG. 5.
[0028] FIG. 7 is an explanatory view illustrating an attached state
of a mounting member by the use of the threaded member in the one
embodiment of the present invention.
[0029] FIG. 8 is a plan view of a washer used in another embodiment
of the present invention.
[0030] FIG. 9 is a cross-sectional view of the washer, the view
being taking along line IX-IX of FIG. 8.
[0031] FIG. 10 is a bottom view of the washer of FIG. 8.
[0032] FIG. 11 is a plan view of another example of the washer used
in another embodiment of the present invention.
[0033] FIG. 12 is a cross-sectional view of the washer, the view
being taken along line XII-XII of FIG. 11.
[0034] FIG. 13 is a bottom view of the washer of FIG. 11.
[0035] FIG. 14 is an explanatory view illustrating an attached
state of the mounting member by the use of the threaded member in a
further embodiment of the present invention.
[0036] FIG. 15 is a time schedule of a temperature condition of a
heat cycle test performed in examples.
BEST MODE FOR CARRYING OUT THE INVENTION
[0037] FIG. 1 is an exploded perspective view showing an embodiment
of a substrate storage container according to the present
invention.
[0038] As shown in FIG. 1, a substrate storage container of the
present invention is constituted by a container body 1 that stores
substrates, a lid 2 and a plurality of mounting members attached
thereto.
[0039] More particularly, the container body 1 is provided on a top
surface thereof with a robotic flange 4 that is adapted to be
gripped by a ceiling conveyance apparatus called OHT (Overhead
Hoist Transportation) for conveying the substrate storage
container. The container body 1 is provided on opposite outer side
walls thereof with respective side rails 6, 6 and respective manual
handles 5, 5 that are projected for conveyance with an AGV
(Automated Guided Vehicle). The container body 1 is also provided
with a bottom plate 8 attached to a bottom surface thereof and
including positioning members 7 having a V-shaped groove which are
disposed at three positions so as to position the container body 1
with respect to a substrate processing apparatus.
[0040] The lid 2 has a pair of latch mechanisms 10 built in that
permit an automatic opening/closing operation thereof from the
outside and a seal member 11 attached around a peripheral edge of a
side wall thereof. A retainer 12 including engagement grooves for
holding the substrates is attached to a surface of the lid 2
opposed to an opening of the container body 1. Threaded members 3
are used to attach mounting members such as the robotic flange 4,
the manual handles 5, 5, the side rails 6, 6, and the bottom plate
8. In the present invention, the mounting members are attached to
the substrate storage container while a locking means is disposed
between each threaded member 3 and the mounting member.
[0041] The embodiment of the present invention will hereinafter be
described taking the side rail 6 as an example of the mounting
member attached to the container body 1.
[0042] FIG. 2 is a perspective view showing an example of the side
rail including a side wall conforming to the wall shape of the
container body, although the shape thereof is somewhat different
from that of the side rails shown in FIG. 1. The side rail 6
includes a flat base and a peripheral wall 13 disposed around the
base and is partitioned into substantially rectangular shapes by a
plurality of ribs 14 located in a reticular pattern to reinforce a
flat portion of the base. The peripheral wall 13 is provided on one
surface thereof with a V-shaped concave portion 15 used for
positioning with respect to a conveyance apparatus.
[0043] As shown in FIG. 3, a stepped portion 16 including a flat
surface is disposed on the under side of the base of the side rail
6. The flat surface of the step portion 16 is formed to be even so
that it can be brought into contact with two horizontal claws
disposed on the conveyance apparatus to lift the substrate storage
container.
[0044] A linear insertion protrusion 18 is disposed integrally on a
part of the side wall opposite from the stepped portion 16 and is
formed so as to be held, without play, between a pair of fixed ribs
17 and 17 (FIG. 1) formed on each of the right and left side walls
of the container body 1.
[0045] The side rail 6 is provided on each of both ends thereof
with a fixing portion 21 having a through-hole 20 so as to attach
and fix the side rail 6 to the side wall of the container body 1.
The threaded members (or male screws) 3 are inserted through the
respective through-holes 20 and threaded (screwed) into other
threaded members (or female screws, not shown) provided on the
container body 1, to thereby fasten the side rail 6 to the
container body 1.
[0046] In the present invention, as shown in FIG. 4, a rugged
portion 22 is formed as a locking means on a circumferential edge
portion of the fixing portion 21 of the side rail 6 around the
through-hole 20, which edge portion comes into contact with the
threaded member 3. The rugged portion 22 includes recesses and
projections that are formed alternately in the circumferential
direction so that the recesses are adapted to be engaged with a
plurality of ribs 25 provided on a surface of the threaded member 3
which comes into contact with the circumferential edge portion
around the through-hole 20 and the projections include inclined
surfaces that guide the ribs 25 of the threaded member 3.
[0047] With regard to the inclined surfaces formed on the sides of
each projection, one is formed to be a gently inclined surface 23
in association with a fastening direction of the threaded member 3
and formed at an angle of, for example, about 20.degree. relative
to a plane parallel to a flat surface of the fixing portion 21,
while the other is formed to be a steeply inclined surface 24 in
association with a loosening direction of the threaded member 3 and
formed at an inclination angle greater than that of the gently
inclined surface 23, for example, about 87.degree.. The gently
inclined surface 23 is formed at the inclination angle within a
range of 10.degree. to 30.degree., and preferably, a range of
15.degree. to 25.degree.; the steeply inclined surface 24 is formed
at the inclination angle within a range of 70.degree. to
90.degree., and preferably, a range of 80.degree. to 88.degree.;
and it is desirable that the gently inclined surface 23 and the
steeply inclined surface 24 be formed to be asymmetric shapes. As
can be clearly seen from FIG. 4, the opposing side surfaces of the
adjacent projections are the inner side surfaces of one recess.
[0048] As shown in FIGS. 5 and 6, the threaded member 3 includes a
plurality of protruded ribs 25 formed on the under side of a head
19 to be extended outward from the center thereof. The height of
the ribs 25 is preferably within a range of 1/2 to 3/4 of the pitch
of the thread of the threaded member 3. In the case of the threaded
member 3 being, for example, an M5 screw according to JIS, since
the pitch thereof is 0.8 mm, the height of the ribs 25 may be set
to 0.5 mm, which is greater than a half of the pitch. The ribs 25
may be formed to have a cross-sectional shape of a trapezoid,
rectangle, circle or the like, which conforms to the shape of the
recesses of the rugged portion 22 provided on the fixing portion 21
of the side rail 6.
[0049] FIG. 7 is a partial explanatory view showing the case in
which the side rail 6 is fixed to the container body 1 by the use
of such threaded members 3. The ribs 25 of the threaded member 3
and the rugged portion 22 provided on the fixing portion 21 of the
side rail 6 are engaged with and fixed to each other. In this
instance, the side surfaces of the ribs 25 of the threaded member 3
are formed at the same inclination angle as that of the steeply
inclined surfaces 24 of the rugged portion 22 of the fixing portion
21 so as to provide surface contact, with the result that the
threaded member 3 is more firmly fixed and the loosening of the
threaded member 3 can be prevented.
[0050] The threaded member 3 is made of an appropriate material,
which preferably is a material with fewer eluted ions and less
emission of volatile gas so as not to contaminate the substrates
received in the substrate storage container, as well as with
sufficient rigidity, impact strength and heat-resistant strength.
For example, the material includes resin material which exhibits
excellent mechanical strength, such as poly(ether ether ketone),
poly(ether imide), poly(ether sulfone), poly(phenyl sulfone),
polyamide, etc., and above all, it is particularly preferred that
the threaded member be made of poly(ether ether ketone).
[0051] It is more preferable to use a washer for the locking means.
FIGS. 8 to 10 show an example of a washer in another embodiment of
the present invention, wherein the mounting member, i.e., the side
rail 6 is fixed to the container body 1 by the use of the washer
between the threaded member 3 and the mounting member. Even when
the washer is used, the aforementioned side rail 6 and threaded
member 3 can be used without modification.
[0052] The washer 26 is provided on one surface thereof with a
plurality of linear protruded ribs 27 with a trapezoidal
cross-sectional shape, which extend from the center of washer 26
toward outside as is the case with the ribs provided on the
threaded member 3. The protruded ribs 27 are located to engage with
the rugged portion 22 provided on the fixing portion 21 of the side
rail 6. The other surface of the washer 26 is provided with notches
28 mating with the respective ribs 25 of the threaded member 3.
[0053] When such a washer 26 is used, since the washer 26 is
deformed and firmly fixed by the ribs 25 of the threaded member 3
through fastening of the threaded member 3, the ribs 27 of the
washer 26 engage with the rugged portion 22 of fixing portion 21 of
the side rail 6, and the ribs 25 of the threaded member 3 engage
with the respective notches 28 of the washer 26, resulting in the
loosening of the threaded member 3 being effectively prevented.
[0054] The washer 26 is preferably used which is made of
polycarbonate resin with excellent mechanical strength and
elasticity, and which can be deformed by the ribs 25 of the
threaded member 3. Further, the washer 26 may be made of
polypropylene resin, polycarbonate resin containing carbon fibers,
or the like. The washer may also be made of resin material with
excellent mechanical strength, such as poly(ether ether ketone),
poly(ether imide), poly(ether sulfone), poly(phenyl sulfone),
polyamide, etc., in addition to polycarbonate and
polypropylene.
[0055] FIGS. 11 to 13 show another example of a washer used in the
substrate storage container according to the present invention.
When this type of washer is used, the aforementioned side rail 6
and threaded member 3 can also be used without modification. The
washer 30 is provided on both front and rear surfaces thereof with
pluralities of ribs 31 and 32, respectively, which are similar to
the ribs provided on the threaded member 3. The ribs 31 and 32 are
located to engage with the rugged portion 22 provided on the fixing
portion 21 of the side rail 6 and the ribs 25 of the threaded
member 3, respectively, so that the loosening of the threaded
member 3 can be prevented more effectively.
[0056] In an embodiment shown in FIG. 14, when the side rail 6 is
fixed to the container body 1 by the threaded members 3, ribs 33 of
the threaded members 3 and ribs 35 provided on at least one surface
of a washer 34 are each formed as a strip-like protrusion with a
semicircular shape in cross section. The washer 34 is provided on
the other surface thereof with concave portions 36 corresponding to
the ribs 33 of the threaded members 3. In addition, the steeply
inclined surfaces 24 of the recesses of the rugged portion 22
provided on the fixing portion 21 of the side rail 6 are each
formed to have a partial circle or circular arc shape in cross
section.
[0057] The ribs 33 and 35 with a semicircular shape in cross
section facilitate the engagement or mating of the threaded member
3 with the mounting member and the engagement or mating of the
mounting member with the washer during fastening of the threaded
member 3. The steeply inclined surfaces 24 are each formed on the
rugged portion 22 of the fixing portion 21 of the side rail 6 in
association with the loosening direction of the threaded member 3,
to thereby effectively prevent the loosening of the threaded
members 3. The cross section of the steeply inclined surfaces is
not limited to a circular arc shape and may be a triangular shape
or rectangular shape.
[0058] Such fixation of the mounting member to the substrate
storage container with the threaded members can be applied not only
to the attachment of the side rail but also to the attachment of
the robotic flange 4 and the bottom plate 8, fixation of other
mounting members, or the attachment and fixation of a plate to the
lid, as described above.
EXAMPLE 1
[0059] A side rail provided with rugged portions on fixing portions
as shown in FIG. 2 and male screws made of poly(ether ether ketone)
resin each having a diameter of 5 mm and having ribs formed on a
head thereof as shown in FIG. 5 were used. The male screws were
each threaded into a female screw formed in a container body made
of polycarbonate resin and were each fastened with a predetermined
torque (0.5 Nm) to fix the fixing portion of the side rail to the
container body; and when the screw was loosened, a torque was
measured as an initial torque. A heat cycle test of 50 cycles was
performed for the side rail which had been fixed to the container
body by fastening the male screws with the predetermined torque
again, and then a torque was measured when the male screw was
loosened and compared with the initial torque value. The torque was
measured with an electric screwdriver that could output or display
a torque. The temperature condition of the heat cycle test was
changed as shown in FIG. 15. More specifically, after being
maintained at a normal temperature of 20.degree. C. for 20 minutes,
the temperature was increased to 100.degree. C. in 40 minutes, was
maintained at 100.degree. C. for 30 minutes, and then was gradually
decreased to the normal temperature in 50 minutes. Such a cycle of
heating and cooling was repeated 50 times.
EXAMPLE 2
[0060] Washers made of polycarbonate resin shown in FIG. 8 were
used in combination with the same side rail, male screws, and
container body as those in example 1 to fix the fixing portions of
the side rail in a manner similar to that in example 1, and thus
the heat cycle test of the side rail was performed.
[0061] For the purpose of comparison, the same heat cycle test as
in examples 1 and 2 was performed using male screws without any rib
on a head thereof and a side rail with no rugged portion on the
fixing portion thereof, wherein the male screws and the side rail
had the same sizes and were made of the same materials as those in
examples 1 and 2, and then torques were measured when the male
screws were each loosened before and after the heat cycle test. The
test results of examples 1 and 2 and the comparative example are
shown in Table 1. TABLE-US-00001 TABLE 1 Comparative Example 1
Example 2 Example Presence of Ribs on Yes Yes No Threaded Member
Presence of Washer No Yes No Presence of Protrusions -- Yes -- on
Washer Rugged Portion on Fixing Yes Yes No Portion Initial Torque
(N m) 0.47 0.49 0.45 Torque after Heat Cycles 0.51 0.53 0.35 (N
m)
[0062] As is apparent from the results of Table 1, when the
mounting member is fixed to the substrate storage container with
the locking means of the present invention interposed between the
contact surfaces of the threaded member and the mounting member,
mounting portions hardly loosen and the change rate of the torque
relative to the initial torque ((initial torque-torque after heat
cycles)/initial torque) is within .+-.10%. In contrast, in the case
of the comparative example without using the locking means, the
change rate of the torque exceeds 20%, and thus there is a problem
in that the screw may loosen during use. Therefore, it is
understood that the present invention can provide the substrate
storage container that can offer stable storage performance for a
long period of time.
INDUSTRIAL APPLICABILITY
[0063] The present invention can be applied not only to a substrate
storage container for semiconductor wafers, etc., but also to
storage containers in various fields, to which mounting members are
fixed and attached by threaded members.
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