U.S. patent application number 12/459749 was filed with the patent office on 2010-01-14 for drain device and method.
Invention is credited to Bertrand Bellet, Arnaud Favre, Cindy Rude.
Application Number | 20100006472 12/459749 |
Document ID | / |
Family ID | 39826373 |
Filed Date | 2010-01-14 |
United States Patent
Application |
20100006472 |
Kind Code |
A1 |
Favre; Arnaud ; et
al. |
January 14, 2010 |
Drain device and method
Abstract
The present invention provides a drain device for a transporting
box with an input/output opening which can be blocked by a box door
and which contains substrate wafers stacked according to parallel
planes. The drain device comprises a volume limited by a sealed
wall divided into at least an upper part with a purging gas inlet
orifice and a lower part with a purging gas outlet orifice, with
the two parts being separated by a sealed partition, and a range of
guides defining the openings arranged parallel to those of the
wafers and connecting with the volume of the drain device to direct
the purging gas towards the transporting box.
Inventors: |
Favre; Arnaud; (Annecy,
FR) ; Rude; Cindy; (Annecy-le-vieux, FR) ;
Bellet; Bertrand; (Chambery, FR) |
Correspondence
Address: |
Carmen Patti Law Group, LLC
One N. LaSalle Street, 44th Floor
Chicago
IL
60602
US
|
Family ID: |
39826373 |
Appl. No.: |
12/459749 |
Filed: |
July 7, 2009 |
Current U.S.
Class: |
206/710 ;
137/1 |
Current CPC
Class: |
H01L 21/67017 20130101;
H01L 21/6735 20130101; Y10T 137/0318 20150401 |
Class at
Publication: |
206/710 ;
137/1 |
International
Class: |
B65D 85/86 20060101
B65D085/86 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 11, 2008 |
FR |
08/54 769 |
Claims
1. Drain device for a transporting box with an input/output opening
which a box door can block and which contains substrate wafers
stacked based on parallel planes, comprising: a volume, limited by
a sealed wall, divided into at least an upper part with a purging
gas inlet orifice and a lower part with a purging gas outlet
orifice, with a sealed partition separating the two parts, and a
main wall, intended to cooperate with the inpuVoutput opening of
the transporting box, roughly perpendicular to the planes of the
wafers and comprising a range of openings, the median plane of
which is parallel to the planes of the wafers, with the openings
connecting the volume of the drain device to the transporting
box.
2. Drain device according to claim 1, in which the dimensions of
the openings in relation to the purging gas inlet orifice are such
that the upper part of the drain device is in overpressure.
3. Drain device according to claim 2, in which the number of
openings is at least equal to the number of wafers contained in the
transporting box.
4. Drain device according to claim 2, in which the openings are
rectangular slots with a length of the same order of magnitude as
the diameter of the substrate wafers.
5. Drain device according to claim 2, in which the openings consist
of holes aligned over a distance of the same order of magnitude as
the diameter of the substrate wafers.
6. Drain device according to claim 1, in which the number of
openings is at least equal to the number of wafers contained in the
transporting box.
7. Drain device according to claim 1, in which the openings are
rectangular slots with a length of the same order of magnitude as
the diameter of the substrate wafers.
8. Drain device according to claim 1, in which the openings consist
of holes aligned over a distance of the same order of magnitude as
the diameter of the substrate wafers.
9. Drain device according to claim 1, also comprising a range of
guides inserted between the openings.
10. Drain device according to claim 9, in which the number of
guides is at least equal to the number of wafers contained in the
transporting box and the guides are arranged in the planes of the
wafers.
11. Drain device according to claim 10, in which each guide is
arranged in the same plane as the wafer to which it corresponds,
with the end of each guide being concave, matching the form of the
corresponding circular wafer.
12. Drain device according to claim 1, also comprising means for a
sealed connection to the input/output opening of the transporting
box.
13. Drain system of a transporting box, with an input/output
opening which a box door can block and containing a stack of
substrate wafers based on parallel planes, using a drain device for
the transporting box; wherein the drain device comprises a volume,
limited by a sealed wall, divided into at least an upper part with
a purging gas inlet orifice and a lower part with a purging gas
outlet orifice, with a sealed partition separating the two parts,
and a main wall, intended to cooperate with the input/output
opening of the transporting box, roughly perpendicular to the
planes of the wafers and comprising a range of openings, the median
plane of which is parallel to the planes of the wafers, with the
openings connecting the volume of the drain device to the
transporting box; wherein the drain system comprises a chamber with
at least one connection orifice to a transporting box equipped with
a chamber door, and comprising means of activating the box door to
open and close the door of the transporting box and means of
activating the drain device to connect it to the transporting
box.
14. Drain method for a transporting box with an input/output
opening which a box door can block and which contains substrate
wafers stacked according to parallel planes, using a drain device
for the transporting box; wherein the drain device comprises a
volume, limited by a sealed wall, divided into at least an upper
part with a purging gas inlet orifice and a lower part with a
purging gas outlet orifice, with a sealed partition separating the
two parts, and a main wall, intended to cooperate with the
input/output opening of the transporting box, roughly perpendicular
to the planes of the wafers and comprising a range of openings, the
median plane of which is parallel to the planes of the wafers, with
the openings connecting the volume of the drain device to the
transporting box; the drain method comprising: connecting the drain
device to the input/output opening of the transporting box,
injecting a purging gas in the upper part of the volume of the
drain device through the purging gas inlet orifice, inserting the
gas into the transporting box through openings, the median plane of
which is parallel to the wafer planes and which connect with the
upper part of the volume of the drain device, collecting the gas
through openings, the median plane of which is parallel to the
wafer planes and which connect with the lower part of the volume of
the drain device, evacuating the gas through the purging gas outlet
orifice in the lower part of the volume of the drain device.
15. Drain method according to claim 14, including the injection of
purging gas into the upper part of the drain device at a pressure
greater than 2 bars.
Description
REFERENCE
[0001] This application is based on and claims the benefit of
French patent application Ser. No. 08/54,769, filed on Jul. 11,
2008, which is incorporated by reference herein in its
entirety.
TECHNICAL FIELD
[0002] The present invention relates to a drain device for a
transporting box used for the displacement of semiconductor
substrates between the different stages in the production of
semiconductor and microelectronic components, for example for the
production of micro-electro-mechanical system (MEMS) or
micro-opto-electro-mechanical system (MOEMS) components.
BACKGROUND
[0003] During production, the substrates, such as masks or slices
of silicon 200 mm or 300 mm in diameter for example, are
transported in transporting boxes which protect them against the
pollution present in the atmosphere in clean rooms.
[0004] The transporting boxes have the advantage of being able to
maintain a controlled atmosphere around the substrates, in which
the presence of contaminating products is avoided as far as
possible. For the transport of substrates in wafers 300 mm in
diameter, one particular type of transporting box is used, known as
an FOUP ("Front Opening Unified Pod"), comprising a sealed
peripheral wall with a lateral input-output opening, which can be
blocked by a door equipped with sealing means. In a transporting
box, the wafers are stacked on top of each other in a sort of rack,
which may also be referred to as a cassette or a basket. The basket
containing up to 25 wafers is generally placed or held on the wall
which constitutes the base of the transporting box.
[0005] The transporting box may be coupled to an input-output
interface for the semiconductor component manufacturing equipment.
The interface is a system allowing the transporting box to be
positioned and its door to be opened. The interface usually
comprises robotic means of activating the door to open and close
the door of the transporting box. This interface (sometimes also
known as a mini-environment), is usually known as an Equipment
Front End Module, or EFEM.
[0006] Control of the contamination during the production of
electronic chips is a major challenge for the semiconductor
industry. The contamination may be caused by particles or gases,
which cause corrosion or form crystals on the wafers for example.
Contamination may have dramatic consequences for chip manufacturers
since the performances of the chip will be severely reduced by
these faults.
[0007] There are solutions to limit the contamination by installing
drain systems in the substrate transporting boxes, advantageously
using the vacuum or a neutral gas. However, these drain systems may
only be used when the transporting box is detached from the
equipment (US-2007-062,561; JP-2007-317 909), in other words when
it is closed. This causes two problems.
[0008] The first problem concerns the duration of the draining
operation, in other words the time to replace the contaminated
atmosphere inside the transporting box with a clean neutral gas,
for example nitrogen. Therefore, draining a closed transporting box
requires the clean gas to be injected through drain ports which
have the disadvantage of not being standard and which have a
limited effect. It therefore takes more than 10 minutes to
incompletely drain a box (R. Bernard and A. Favre: "Using numerical
simulation to optimize 300 mm FOUP purging", Solid State Techn.,
October 2003, p. 71). Furthermore, the vacuum process requires the
transporting box to be placed in a vacuum and a return to
atmospheric pressure progressively so as avoid the risk of damaging
the box.
[0009] The second problem is that a transporting box containing the
substrates may remain connected to the equipment for several hours.
Even though it is possible to carry out a draining operation after
having treated the entire batch of substrates contained in the
transporting box, irreversible faults have already appeared.
SUMMARY
[0010] The invention in one implementation encompasses a drain
device for a transporting box with an input/output opening which a
box door can block and which contains substrate wafers stacked
based on parallel planes. The drain device comprises a volume,
limited by a sealed wall, divided into at least an upper part with
a purging gas inlet orifice and a lower part with a purging gas
outlet orifice, with a sealed partition separating the two parts.
The drain device also comprises a main wall, intended to cooperate
with the input/output opening of the transporting box, roughly
perpendicular to the planes of the wafers and comprising a range of
openings, the median plane of which is parallel to the planes of
the wafers, with the openings connecting the volume of the drain
device to the transporting box.
[0011] The invention in another implementation encompasses a drain
system of a transporting box, with an input/output opening which a
box door can block and containing a stack of substrate wafers based
on parallel planes, using a drain device for the transporting box.
The drain device comprises a volume, limited by a sealed wall,
divided into at least an upper part with a purging gas inlet
orifice and a lower part with a purging gas outlet orifice, with a
sealed partition separating the two parts, and a main wall,
intended to cooperate with the input/output opening of the
transporting box, roughly perpendicular to the planes of the wafers
and comprising a range of openings, the median plane of which is
parallel to the planes of the wafers, with the openings connecting
the volume of the drain device to the transporting box. The drain
system comprises a chamber with at least one connection orifice to
a transporting box equipped with a chamber door, and comprising
means of activating the box door to open and close the door of the
transporting box and means of activating the drain device to
connect it to the transporting box.
[0012] In yet another implementation, the invention encompasses a
drain method for a transporting box with an input/output opening
which a box door can block and which contains substrate wafers
stacked according to parallel planes, using a drain device for the
transporting box. The drain device comprises a volume, limited by a
sealed wall, divided into at least an upper part with a purging gas
inlet orifice and a lower part with a purging gas outlet orifice,
with a sealed partition separating the two parts, and a main wall,
intended to cooperate with the input/output opening of the
transporting box, roughly perpendicular to the planes of the wafers
and comprising a range of openings, the median plane of which is
parallel to the planes of the wafers, with the openings connecting
the volume of the drain device to the transporting box. The drain
device is connected to the input/output opening of the transporting
box. A purging gas is injected in the upper part of the volume of
the drain device through the purging gas inlet orifice. The gas is
inserted into the transporting box through openings, the median
plane of which is parallel to the wafer planes and which connect
with the upper part of the volume of the drain device. The gas is
collected through openings, the median plane of which is parallel
to the wafer planes and which connect with the lower part of the
volume of the drain device. The gas is evacuated through the
purging gas outlet orifice in the lower part of the volume of the
drain device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Other characteristics and advantages of the present
invention will become apparent upon reading the following
description of one embodiment, which is naturally given by way of a
non-limiting example, and in the attached drawing, in which:
[0014] FIG. 1 shows in diagram form a substrate treatment
installation to which a transporting box is connected,
[0015] FIGS. 2a, 2b and 2c show in diagram form the way in which a
FOUP transporting box is connected to a drain system according to
one embodiment of the invention,
[0016] FIGS. 3a and 3b represent perspective views, of the two
faces respectively, of a drain device according to one embodiment
of the invention,
[0017] FIG. 4 shows a perspective view of one of the faces of a
drain device according to another embodiment of the invention,
[0018] FIG. 5 shows the path of the purging gas between the
different planes in a transporting box coupled to the purging
device of FIGS. 3a and 3b.
DESCRIPTION OF EMBODIMENTS
[0019] One embodiment of the present invention provides a device to
effectively drain an FOUP transporting box, containing substrate
wafers, while it is still connected to the equipment.
[0020] The invention also provides a drain device which can be
adapted to all standard FOUP type transporting boxes.
[0021] A wafer is extracted or inserted into the transporting box
approximately every 2 to 3 minutes. It is therefore a time
constraint to carry out the draining operation as a background task
during the treatment of a batch of substrates. The invention
therefore also provides a draining method which can be used to
obtain an efficient draining of a FOUP transporting box in under 3
minutes when it is connected to the equipment.
[0022] The present invention provides a drain device for a
transporting box with an input/output opening which can be blocked
by a box door and which contains substrate wafers stacked on
parallel planes, comprising: [0023] a volume, limited by a wall,
divided into at least an upper part equipped with a purging gas
inlet orifice and a lower part equipped with a purging gas outlet
orifice, with the two parts being separated by a sealed partition,
and [0024] a main wall, intended to cooperate with the input/output
opening of the transporting box, roughly perpendicular to the
planes of the wafers and comprising a range of openings, the median
plane of which is parallel to the planes of the wafers, with the
openings connecting the volume of the drain device to the
transporting box.
[0025] According to one preferential execution method, the
dimensions of the openings in relation to the purging gas inlet
orifice are such that the upper part of the drain device is in
overpressure. It is understood that the total surface area of the
connection openings between the upper part of the drain device and
the transporting box must be sufficiently small.
[0026] The number of openings should preferably be at least equal
to the number of wafers contained in the transporting box so as to
direct the purging gas respectively towards each wafer.
Transporting boxes may usually contain between 1 and 25 wafers.
[0027] According to a first embodiment of the invention, the
openings are rectangular slots. Advantageously, the openings have a
length of the same order of magnitude as the diameter of the
substrate wafers. Preferably, the rectangular slots have a height
of less than the distance separating two successive wafers, or
around 10 mm, and the slots are preferably less than 3 mm high.
[0028] According to a second embodiment, the openings consist of
aligned holes. Advantageously, the holes are aligned over a
distance of the same order of magnitude as the diameter of the
substrate wafers. The holes are preferably circular and have a
diameter lower than the distance separating two successive wafers,
and the holes preferably have a diameter of less than 2 mm.
[0029] According to one variant, the drain device comprises among
other things a range of guides inserted between the openings. The
number of guides is preferably at least equal to the number of
wafers contained in the transporting box. These guides are used to
direct the gas stream as close as possible to the wafers.
[0030] According to one execution method, the guides have a length
of the same order of magnitude as the diameter of the substrate
wafers.
[0031] According to another execution method of the invention, the
guides are arranged in the planes of the wafers. Therefore, each
guide is presented in the same plane as the wafer to which it
corresponds. Advantageously, the end of each guide has a concave
form which matches the form of the corresponding circular
wafer.
[0032] Preferably, the drain device also comprises sealed
connection means at the input/output opening of the transporting
box.
[0033] The invention also provides a system for draining, using the
drain device described previously, a transporting box with an
input/output opening which can be blocked by a box door and
containing a stack of substrate wafers. According to one embodiment
of the invention, the drain system comprises a chamber, with at
least one connection orifice to a transporting box equipped with a
chamber door, and comprises means of activating the box door to
open and close the transporting box door and means of activating
the drain device to connect it to the transporting box.
[0034] The idea is to affix a drain device forming a door in the
place of the door of the transporting box, and to use this drain
device to inject a clean gas into the transporting box.
[0035] The drain system also comprises sealing means at the
coupling zone of the connection orifice to the input/output opening
of the transporting box.
[0036] The invention also provides a method for draining, using the
drain device described previously, a transporting box with an
input/output opening which can be blocked by a box door and
containing substrate wafers stacked on parallel planes. According
to one embodiment of the invention, the method includes the
following stages: [0037] the drain device is connected to the
input/output opening of the transporting box, [0038] a clean gas is
injected into the upper part of the volume of the drain device
through the purging gas inlet orifice, [0039] the gas is inserted
into the transporting box through openings, the median plane of
which is parallel to the wafer planes and which connects with the
upper part of the volume of the drain device, [0040] the gas is
collected through openings, the median plane of which is parallel
to the wafer planes and which connects with the lower part of the
volume of the drain device, [0041] the gas is evacuated through the
purging gas outlet orifice in the lower part of the volume of the
drain device.
[0042] Advantageously, the purging gas is injected into the upper
part of the drain device at a pressure greater than 2 bars.
[0043] The drain method with the drain device according to one
embodiment of the invention acts by forced convection between the
substrate wafers. It is used to gain efficiency in relation to
existing drain devices acting by diffusion. The draining operation
is quicker: 1 minute instead of several minutes. After 1 minute of
circulation of the purging gas at 50 slm, there remains on average
less than 3.4% dioxygen in the transporting box.
[0044] This drain device and this drain method can be used with all
FOUP type transporting boxes currently in service.
[0045] For an equivalent flow, the neutral gas enters the
transporting box at a much lower speed than if the draining is
carried out using drain orifices arranged in the back wall of the
standard transporting boxes. For this reason, there are fewer
particles detached and blown inside the transporting box.
Furthermore, backscattering is not possible for these particles,
therefore the wafers are protected against any risk of
redeposition.
[0046] The draining operation may be used either at the end of the
treatment before reclosing and disconnecting the transporting box,
or as a background task during the treatment between two wafer
transfer operations. The time required to reach a draining
efficiency of greater than 90% is less than 2 minutes with a
purging gas flow of 30 slm. This time is shorter than the duration
passing between two wafer transfers.
[0047] A substrate treatment installation is shown in FIG. 1. It
contains a process chamber 1, maintained in a vacuum in which
manufacturing or treatment operations are carried out for
substrates such as semiconductor wafers. The process chamber 1
connects to a transfer chamber 2, also in a vacuum, in which the
wafer is placed immediately before and after its treatment in the
process chamber 1. The transfer chamber 2 connects to a
loading/unloading lock 3 in which the vacuum and return to
atmospheric pressure phases alternate. This lock 3 connects the
transfer chamber 2 to an EFEM module 4 used to transfer substrates
at atmospheric pressure. One or more removable transporting boxes
5, of the FOUP type for example, may be connected via an orifice 6
to the EFEM module 4. These boxes 5 are used for the storage or the
transport of substrates at atmospheric pressure, in particular
between two manufacturing phases or between two treatment devices.
The substrate wafers stacked in a basket 7 may therefore be
transferred one by one to the transfer chamber 2 via the EFEM
module 4 and the lock 3.
[0048] FIGS. 2a, 2b and 2c correspond to the successive stages of
the coupling of a FOUP type transporting box to the drain device
according to one embodiment of the invention.
[0049] FIG. 2a shows a drain system 20 according to one embodiment
of the invention comprising a chamber 21 with sealed walls
comprising at least one orifice 22 to allow the coupling of a
transporting box 23. A basket 24 containing substrate wafers
arranged horizontally is placed in the transporting box 23. The
transporting box 23 comprises side walls 23a, a top wall 23b and a
bottom wall 23c on which the basket rests 24. In one of the side
walls 23a, there is an input/output opening blocked by a door 25.
The door 25 is placed opposite the orifice 22 of the drain system
20. A drain device 26 according to one embodiment of the invention
is placed in the lower part of the chamber 21. If the drain system
20 provides the functions of an EFEM module, it also comprises a
second orifice 27 able to be connected to the loading/unloading
lock for a substrate treatment installation.
[0050] Once the transporting box 23 is placed opposite the orifice
22 of the drain system 20, its door 25 is unlocked using means of
activating the box door, then moved to the lower part of the
chamber 21 for example, in order not to hinder the displacement of
the wafers to the loading/unloading lock, as shown in FIG. 2b.
[0051] The drain device 26 is positioned by robotic means of
activation in the place of the door 25 of the transporting box 23
in order to drain the transporting box 23 and the substrate wafers
it contains, as shown in FIG. 2c. The drain device 26 is applied to
the box 23 to seal it closed. This operation to put in place the
drain device 26 may be carried out at the end of the treatment of
the entire batch of substrates and/or between each displacement of
wafers to the method chamber.
[0052] A specific embodiment of the drain device according to the
invention is represented in FIGS. 3a and 3b. The drain device 30
comprises a volume limited by a sealed wall divided into an upper
part 31 and a lower part 32 by a sealed separating partition 33.
The upper part 31 comprises an inlet orifice 34 for the purging
gas. The lower part 32 comprises an outlet orifice 35 for the
evacuation of the gas. The volume of the drain device is closed on
the drain system chamber side by a sealed wall (not shown) and open
towards the inside of the transporting box. The drain device 30
comprises horizontal guides 36 which restrict the openings 37, the
number of which must be equal to the number of wafers contained in
the basket. The input/output opening of the box has dimensions
slightly greater than the diameter of the substrate wafers in order
to allow passing. The drain device 30 which blocks it as a
replacement for the box door shall therefore have similar
dimensions, and the guides 36 and the openings 37 shall therefore
have a length of the same order of magnitude as that of the wafers.
In the present case, the openings 37 are rectangular slots with a
length of around 300 mm and a height of less than 3 mm. The end of
each guide 36 is concave 38, matching the form of the circular
wafer arranged horizontally in the basket, in order to bring the
purging gas as close as possible to each wafer to sweep over the
surface. A joint 39 ensures the sealing of the connection between
the transporting box and the drain device 30.
[0053] FIG. 4 shows a perspective of another embodiment of a drain
device 40 comprising a gas inlet orifice 41. Here, the openings 42
consist of parallel rows of holes 43, each horizontal row
corresponding to the horizontal plane of a wafer. The drain device
40 does not contain guides.
[0054] The drain method will now be described in reference to FIG.
5. A drain device 50 according to one embodiment of the invention
is connected and sealed to the input/output opening of a
transporting box 51 so as to connect the volume of the drain device
50 to the inside of the transporting box 51. A clean purging gas,
preferably a neutral gas, is injected through the gas inlet orifice
52 in the upper part 53 of the drain device volume 50,
advantageously at a pressure greater than 2 bars. The purging gas
is then directed through the openings 54 by the guides 55 around
and towards the inside of the basket 56. The purging gas flow
travels in parallel to the planes of the wafers 57, to the planes
of the guides 55 and to the median planes of the openings 54, as
shown by arrows 58 and 59 respectively.
[0055] After flushing the wafers located in the top of the basket
56, the purging gas returns to the lower part 60 of the drain
device volume 50, flushing the wafers located in the bottom of the
basket 56, as shown by arrows 61 and 62. The purging gas then
escapes through the outlet orifice 63.
[0056] The openings 54 are dimensioned in relation to the gas inlet
orifice 52 in such a way that the upper part 53 of the drain device
50 is in slight overpressure, in order that the neutral and clean
gas can enter homogeneously in the transporting box 51. The
openings 54 may take the form of slots with a low height or a
series of aligned holes with a low diameter, for example with a
diameter of less than 2 mm. A low cross section for these openings
54 allows gas input with homogeneous distribution over the entire
surface of the upper part 53 of the drain device 50.
* * * * *