U.S. patent application number 16/629049 was filed with the patent office on 2020-07-02 for drying device and method for drying a substrate.
The applicant listed for this patent is RENA TECHNOLOGIES GMBH. Invention is credited to STEFAN HANSEN, TOBIAS ROSSHART, MARKUS UIHLEIN.
Application Number | 20200208913 16/629049 |
Document ID | / |
Family ID | 63998463 |
Filed Date | 2020-07-02 |
United States Patent
Application |
20200208913 |
Kind Code |
A1 |
UIHLEIN; MARKUS ; et
al. |
July 2, 2020 |
DRYING DEVICE AND METHOD FOR DRYING A SUBSTRATE
Abstract
A drying device contains an upper drying head and a lower drying
head. The upper drying head is arranged above a transport plane, in
which objects to be dried can be transported in a transport
direction through the drying device. The lower drying head is
arranged below the transport plane. The upper drying head and the
lower drying head contain in each case at least one air outlet slot
and the longitudinal directions of the air outlet slots essentially
extending parallel to the transport plane and transversely to the
transport direction, and in which slot planes, in which the air
outlet slots extend, intersect the transport plane at angles which
are greater than 0.degree. and less than 90.degree..
Inventors: |
UIHLEIN; MARKUS;
(GUETENBACH, DE) ; HANSEN; STEFAN; (GUETENBACH,
DE) ; ROSSHART; TOBIAS; (GUETENBACH, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
RENA TECHNOLOGIES GMBH |
GUETENBACH |
|
DE |
|
|
Family ID: |
63998463 |
Appl. No.: |
16/629049 |
Filed: |
July 12, 2018 |
PCT Filed: |
July 12, 2018 |
PCT NO: |
PCT/DE2018/100641 |
371 Date: |
January 7, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 21/6776 20130101;
F26B 21/004 20130101; F26B 15/14 20130101; H05K 3/227 20130101;
F26B 2015/003 20130101; H01L 21/67034 20130101 |
International
Class: |
F26B 15/14 20060101
F26B015/14; H01L 21/67 20060101 H01L021/67; F26B 21/00 20060101
F26B021/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 14, 2017 |
DE |
10 2017 115 875 |
Claims
1-21. (canceled)
22. A drying device, comprising: drying heads including at least
one upper drying head and at least one lower drying head, wherein
said at least one upper drying head is disposed above a transport
plane, in which objects to be dried can be transported in a
transport direction through the drying device, and said at least
one lower drying head is disposed below the transport plane; and
said at least one upper drying head and said at least one lower
drying head having air outlet slots formed therein with each having
at least one air outlet slot of said air outlet slots, longitudinal
directions of said air outlet slots extend substantially parallel
to the transport plane and transversely to the transport direction,
and slot planes, in which said air outlet slots run, intersect the
transport plane at angles which are greater than 0.degree. and less
than 90.degree..
23. The drying device according to claim 22, wherein the slot
planes, in which said air outlet slots run, intersect the transport
plane at angles which are greater than 60.degree. and less than
80.degree..
24. The drying device according to claim 22, wherein said air
outlet slots have a substantially uniform slot depth which assumes
a value between 1 mm and 5 mm.
25. The drying device according to claim 22, wherein said air
outlet slots have a slot width which is greater than or equal to
0.3 mm and less than or equal to 0.7 mm.
26. The drying device according to claim 22, further comprising
stiffening webs for stabilizing forms of said air outlet slots.
27. The drying device according to claim 22, wherein at least one
of said drying heads has: a base plate in which a pocket for air
guidance is machined; and a cover connected to said base plate and
by means of which said pocket can be closed so as to form a
cavity.
28. The drying device according to claim 22, further comprising an
angled plate for stiffening at least one of said drying heads.
29. The drying device according to claim 22, wherein the
longitudinal direction of at least one of said air outlet slots
extends transversely to the transport direction, such that the
longitudinal direction deviates from the transport direction by an
angle of 87.degree. or less.
30. The drying device according to claim 22, wherein the
longitudinal direction of at least one of said air outlet slots
extends substantially perpendicularly to the transport
direction.
31. The drying device according to claim 22, wherein said upper
drying head and said lower drying head, forming a drying head pair,
are disposed above each other such that the slot planes, in which
said air outlet slots of said upper drying head of said drying head
pair run, form intersection lines with the transport plane which
coincide with intersection lines formed with the transport plane by
the slot planes in which said air outlet slots of said lower drying
head of said drying head pair run.
32. The drying device according to claim 22, wherein: said upper
drying head and said lower drying head, forming a drying head pair,
are disposed above each other such that the slot planes, in which
said air outlet slots of said upper drying head of said drying head
pair run, form first intersection lines with the transport plane
which run parallel to second intersection lines formed with the
transport plane by the slot planes in which said air outlet slots
of said lower drying head of said drying head pair run; and the
first intersection lines are offset in the transport direction
relative to the second intersection lines by a value between 1 mm
and 5 mm.
33. The drying device according to claim 22, wherein: said upper
drying head and said lower drying head, forming a drying head pair,
are disposed above each other; said upper drying head and said
lower drying head of said drying head pair have stabilizing slots
formed therein with each having at least one stabilizing slot of
said stabilizing slots through which a medium can flow, said
stabilizing slots are each disposed offset in the transport
direction next to one of said air outlet slots; longitudinal
directions of said stabilizing slots extend substantially parallel
to the transport plane and transversely to the transport direction
at an angle deviating from 90.degree.; and said at least one
stabilizing slot of said upper drying head and said at least one
stabilizing slot of said lower drying head are disposed in pairs
such that an air front, flowing out of said stabilizing slot of a
stabilizing slot pair disposed in said upper drying head,
intersects in the transport plane an air front flowing out of said
stabilizing slot of said stabilizing slot pair disposed in said
lower drying head.
34. The drying device according to claim 31, wherein said drying
head pair is one of at least two drying head pairs which are
disposed next to each other in the transport direction.
35. The drying device according to claim 22, wherein the
longitudinal directions of all of said air outlet slots extend
substantially perpendicularly to the transport direction.
36. A method for drying a sheet-shaped substrate in a continuous
system, which comprises the steps of: providing an upper air jet
extending over an entire width of the sheet-shaped substrate and
flowing onto a top side of the sheet-shaped substrate; and
providing, at a same time, a lower air jet extending over the
entire width of the sheet-shaped substrate and flowing onto an
underside of the sheet-shaped substrate, the upper air jet and
lower air jet flow onto the top side and the underside respectively
of the sheet-shaped substrate at angles, relative to a transport
plane in which the sheet-shaped substrate is transported, which are
greater than 0.degree. and less than 90.degree..
37. The method according to claim 36, wherein the upper air jet and
the lower air jet flow onto the top side and the underside
respectively of the sheet-shaped substrate at angles, relative to
the transport plane, which are greater than 60.degree. and less
than 80.degree..
38. The method according to claim 36, which further comprises
orienting the upper air jet and the lower air jet such that they
make contact first with the top side of the sheet-shaped substrate
and second with the underside of the sheet-shaped substrate in
mutually opposing regions.
39. The method according to claim 36, which further comprises
orienting the upper air jet and the lower air jet such that they
make contact with the sheet-shaped substrate offset to each other
in the transport direction by a value between 1 mm and 5 mm.
40. The method according to claim 36, wherein the upper air jet and
the lower air jet make contact with a rear edge of the sheet-shaped
substrate in flow directions which are angled obliquely, such that
the rear edge encloses an angle of 3.degree. or more with an inflow
direction of the upper air jet and also with an inflow direction of
the lower air jet.
41. The method according to claim 36, wherein to stabilize the
sheet-shaped substrate, an upper stabilizing air jet flows onto the
top side and a lower stabilizing air jet flows onto the underside,
wherein the lower stabilizing air jet has a flow direction which is
oriented opposite a flow direction of the upper stabilizing air
jet.
42. The method according to claim 41, wherein the upper stabilizing
air jet forms a jet profile which runs contrary to a jet profile of
the lower stabilizing air jet.
Description
[0001] The invention concerns a drying device according to the
preamble of claim 1, and a method for drying a sheet-like substrate
in a continuous system according to the preamble of the independent
method claim.
[0002] Sheet-like substrates are often treated with liquids, after
which it is necessary to then dry the sheet-like substrate. For
example, in the production of solar cells, semiconductor
substrates--which constitute sheet-like substrates and are often
described as wafers--are processed in a wet chemical method. In
this context, it is usually necessary to dry the semiconductor
substrates, in some cases after prior rinsing in water.
[0003] When sheet-like substrates are treated or processed on an
industrial scale, for example in the industrial production of solar
cells from semiconductor substrates, this regularly takes place
with continuous processes and continuous systems through which the
sheet-like substrates are transported. It is known, for the purpose
of drying the semiconductor substrates in such continuous
processes, to conduct air through perforated plates or similar on
the top side and underside of the semiconductor substrate, and
displace any liquid present on the surface by means of the
inflowing air. It has however been found that with high transport
speeds of the sheet-like substrates through corresponding
continuous systems, it is not possible to achieve satisfactory
drying results, and liquid droplets or damp regions can remain.
This is the case even if the sheet-like substrates are dried in the
manner described twice in succession.
[0004] In this context, the object of the present invention is to
provide a device by means of which sheet-like substrates can be
reliably dried in continuous operation.
[0005] This object is achieved with a drying device with the
features of claim 1.
[0006] Furthermore, the invention is based on the object of
providing a method by means of which sheet-like substrates can be
reliably dried in a continuous system at high transport speeds of
the sheet-like substrates through the continuous system.
[0007] This object is achieved by a method with the features of the
independent method claim.
[0008] Advantageous refinements are the subject of the dependent
claims.
[0009] The drying device according to the invention comprises at
least one upper drying head and at least one lower drying head. The
at least one upper drying head is arranged above a transport plane
in which objects to be dried can be transported through the drying
device in a transport direction. The at least one lower drying head
is arranged below said transport plane. The at least one upper
drying head and the at least one lower drying head each comprise at
least one air outlet slot. Said air outlet slots are formed and
arranged such that longitudinal directions of said air outlet slots
extend substantially parallel to the transport plane and
transversely to the transport direction. Furthermore, they are
formed and arranged such that slot planes, in which said air outlet
slots run, intersect the transport plane at angles which are
greater than 0.degree. and less than 90.degree..
[0010] The term "air outlet slot" in the present case should not be
understood to mean that air must necessarily be used for drying.
Instead, in principle other gases or gas mixtures may be used as a
drying medium. Where the present description mentions "air", this
term also always includes other gases or gas mixtures which could
be used for drying.
[0011] It has been found that with the drying device described,
sheet-like substrates can be reliably dried in continuous operation
even at high transport speeds of the sheet-like substrates through
the drying device.
[0012] In principle, said angles may be different for all slot
planes. In a preferred variant however, said angles are selected
uniformly for the slot planes in which the at least one air outlet
slot of the at least one upper drying head runs, and said angles
assume a first measured value. Furthermore, in this variant, said
angles are selected uniformly for the slot planes in which the at
least one air outlet slot of the at least one lower drying head
runs, and said angles assume a second measured value. Particularly
preferably, said angles are the same for all slot planes, i.e. the
first measured value and the second measured value are
identical.
[0013] By means of said air outlet slots, advantageously continuous
air jet fronts may be formed. For this, in connection with silicon
semiconductor substrates, air outlet slots with a length of 180 mm
have proved useful.
[0014] In particular in connection with the drying of semiconductor
substrates made of silicon, it has proved advantageous for the
drying results if the slot planes, in which said air outlet slots
run, intersect the transport plane at angles which are greater than
60.degree. and less than 80.degree.. Preferably, these angles are
greater than 65.degree. and less than 75.degree., and particularly
preferably amount to 70.degree..
[0015] Preferably, the air outlet slots have a uniform slot depth
of between 1 mm and 5 mm. Preferably, the slot depth amounts to
between 2 mm and 4 mm, and particularly preferably between 2.5 mm
and 3.5 mm. These slot depths have proved particularly suitable in
practice.
[0016] The air outlet slots preferably have a slot width which is
greater than or equal to 0.3 mm and less than or equal to 0.7 mm.
Particularly preferably, the slot width amounts to 0.5 mm. In this
way, efficient drying can be achieved.
[0017] It has been found that a constant slot cross-section has
substantial influence on the drying result. In order to stabilize
the form and hence the cross-sections of the air outlet slots, in
an advantageous refinement therefore stiffening webs are provided
which are suitable for stabilizing the forms of the air outlet
slots over their slot length. This is particularly advantageous if
greater slot lengths are selected which extend over an entire width
of the sheet-like substrates to be dried.
[0018] In a preferred embodiment variant of the drying device, at
least one drying head has a base plate in which a pocket for air
guidance is machined. Furthermore, a cover is provided which can be
connected to the base plate and by means of which the pocket can be
closed so as to form a cavity. This cavity then serves for
so-called air guidance in the drying head towards the air outlet
slots. This allows favorable production of the at least one drying
head. Preferably, all drying heads are configured in the manner
described. The term "air guidance" in the present case includes the
guidance of another gaseous drying medium. Several covers of
various drying heads may be connected together via a pipeline
through which medium can flow. Preferably, in each case, two covers
are connected together directly by such pipelines. This allows an
even air distribution.
[0019] A refinement of the drying device provides an angled plate
which is suitable and provided for stiffening at least one drying
head. Such an angled plate may then be laid in the pocket machined
in the base plate, or attached externally to the base plate.
Preferably, all drying heads are provided with an angled plate.
[0020] Advantageously, the longitudinal direction of at least one
air outlet slot extends transversely to the transport direction,
such that said longitudinal direction deviates from the transport
direction by an angle of 87.degree. or less. This can prevent an
air jet, which emerges from said at least one air outlet slot, from
making contact parallel to a rear edge of the sheet-like substrates
to be dried. Due to the avoidance of this parallel contact, when
passing through the drying device, any liquid present on the rear
edge can be pushed from one end of the rear edge to the opposite
end of the rear edge by the air jet running obliquely relative to
the rear edge. This is advantageous in particular if the liquid has
a tendency to adhere to edges. Preferably, said angle amounts to
more than 75.degree. and is less than or equal to 87.degree.. In
this way, it is possible to take account of the restricted spatial
conditions in continuous systems, in particular in the case of
multitrack systems in which the sheet-like substrates to be dried
are transported through the drying device on several tracks next to
each other. An angle of 87.degree. has proved particularly suitable
in practice.
[0021] In some applications, it may be advantageous if the
longitudinal directions of all air outlet slots extend transversely
to the transport direction in the manner described above. This may
be the case for example when the liquid has a very strong tendency
to adhere to edges. In addition, in this way, stabilization may be
achieved if the sheet-like substrates have a tendency to
vibrations. Such vibrations may be caused by the deflection effects
of air jets in the drying device. Above all in the case of thin
sheet-like substrates, such vibrations may lead to breakage of the
sheet-like substrate.
[0022] A refinement of the invention provides that the longitudinal
direction of at least one air outlet slot extends substantially
perpendicularly to the transport direction. This may be
advantageous in the case of restricted spatial conditions in the
transport direction, in particular if stabilization slots
(described below) are also provided. When the spatial conditions in
the transport direction are particularly restricted, it may be
advantageous if the longitudinal directions of all air outlet slots
extend perpendicularly to the transport direction. The drying heads
may then be constructed particularly compactly.
[0023] In an advantageous embodiment variant of the drying device,
an upper drying head and a lower drying head, forming a drying head
pair, are arranged above each other such that the slot planes, in
which the air outlet slots of the upper drying head of the drying
head pair run, form intersection lines with the transport plane
which coincide with intersection lines formed with the transport
plane by the slot planes in which the air outlet slots of the lower
drying head of the drying head pair run. In this way, the
sheet-like substrate may be quasi-enclosed by a closed air jet
ring. This allows a particularly efficient drying.
[0024] Alternatively or in a further drying head pair, it may
advantageously be provided that an upper drying head and a lower
drying head, forming a drying head pair, are arranged above each
other such that the slot planes, in which the air outlet slots of
the upper drying head of the drying head pair run, form first
intersection lines with the transport plane which run parallel to
second intersection lines formed with the transport plane by the
slot planes in which the air outlet slots of the lower drying head
of the drying head pair run. Furthermore, the arrangement is such
that the first intersection lines are offset in the transport
direction relative to the second intersection lines by a value
between 1 mm and 5 mm. Preferably, this offset amounts to between 1
mm and 3 mm, and particularly preferably 2 mm. In this variant, the
air jets from the upper drying head and the lower drying head do
not make contact at mutually opposing locations on the top side and
underside of the sheet-like substrate, but are offset to each
other. This may lead to a less efficient drying, but on the other
hand, in this way, the above-mentioned tendency to vibration, which
occurs in many applications with the associated risk of breakage,
can be reduced or avoided. In practice, an arrangement in which the
first intersection lines are offset downstream in the transport
direction relative to the second intersection lines has proved
particularly suitable.
[0025] In an advantageous variant, at least two drying head pairs
are provided which are arranged successively in the transport
direction. These two drying head pairs may be configured
identically. In principle, the two drying head pairs may however
also be different, in order to meet the requirements of the
respective application. For example, in the case of a second drying
head pair, the drying heads could be arranged such that the first
and second intersection lines are offset to each other in the
manner described above, while in the first drying head pair, the
drying heads are arranged such that the intersection lines coincide
as described further above.
[0026] A refinement proposes that an upper drying head and a lower
drying head, forming a drying head pair, are arranged above each
other. The upper and the lower drying heads of the drying head pair
each have at least one stabilizing slot through which medium can
flow. Said stabilizing slots are each arranged offset in the
transport direction next to an air outlet slot. Furthermore, said
stabilizing slots are formed and arranged such that their
longitudinal directions extend substantially parallel to the
transport plane and transversely to the transport direction at an
angle deviating from 90.degree.. Furthermore, the at least one
stabilizing slot of the upper drying head and the at least one
stabilizing slot of the lower drying head are arranged in pairs,
such that an air front flowing out of the stabilizing slot of a
stabilizing slot pair arranged in the upper drying head, in the
transport plane, intersects the air front flowing out of the
stabilizing slot of this stabilizing slot pair arranged in the
lower drying head. Or in other words, the stabilizing slots of the
stabilizing slot pair are oriented contrary to each other relative
to the transport direction, so that the air fronts flowing out of
the stabilizing slots of this stabilizing slot pair intersect in
the transport plane.
[0027] By means of the stabilizing slots, the tendency (already
described above) of many sheet-like substrates to vibrate, and the
associated risk of breakage, are further reduced. It is also
possible to use stabilizing slots instead of other measures for
avoiding vibrations. The drying device may thus be designed
optimally for the respective application and its peripheral
conditions, such as for example restricted spatial conditions. For
example, a combination of stabilizing slots and air outlet slots
extending substantially perpendicularly to the transport direction
may prove highly advantageous in restricted spatial conditions and
when there is a vibration tendency. Amongst others, in this
exemplary case it may be advantageous if all air outlet slots of
the drying device, or at least the drying head pair, extend
substantially perpendicularly to the transport direction.
[0028] The method according to the invention for drying a
sheet-like substrate in a continuous system provides that an upper
air jet extending over the entire width of the sheet-like substrate
flows onto a top side of the sheet-like substrate. At the same
time, a lower air jet extending over the entire width of the
sheet-like substrate flows onto an underside of the sheet-like
substrate. The upper and lower air jets flow onto the top side and
the underside of the sheet-like substrate at angles relative to a
transport plane, in which the sheet-like substrate is transported,
which are greater than 0.degree. and less than 90.degree..
[0029] The term "top side" of the sheet-like substrate means a
first large-area side of the sheet-like substrate; the term
"underside" means a second large-area side of the sheet-like
substrate. The medium does not necessarily make contact with the
top side and underside of the sheet-like substrate at the same
angles; said angles may in principle differ from each other, in
particular if this proves advantageous in the respective
application. Normally however, the contact angles are the same.
[0030] The method according to the invention allows sheet-like
substrates to be reliably dried in continuous systems even at high
transport speeds through the continuous system, in particular a
transport speeds of more than 2.6 m/minute. With inflow from air
jets extending over the entire width of the sheet-like substrate,
almost no liquid can escape the air jets. The sheet-like substrate
can be reliably dried over its entire width.
[0031] Preferably, the upper air jet flows onto the top side of the
sheet-like substrate, and the lower air jet flows onto the
underside of the sheet-like substrate, against a transport
direction in which the sheet-like substrate is transported in the
transport plane. The term "against the transport direction" in the
present case means that a flow direction of the air jet has a
direction component which is oriented opposite the transport
direction.
[0032] Advantageously, the upper air jet flows onto the top side
and the lower air jet flows onto the underside of the sheet-like
substrate at angles relative to a transport plane, in which the
sheet-like substrate is transported, which are greater than
60.degree. and less than 80.degree.. Preferably, these angles are
greater than 65.degree. and less than 75.degree.. In practice, an
angle of 70.degree. has proved particularly suitable.
[0033] Preferably, the upper air jet and the lower air jet are
oriented such that they make contact with the sheet-like substrate
in mutually opposing regions, which lie firstly on the top side of
the sheet-like substrate and secondly on the underside of the
sheet-like substrate. In this way, a composite air jet may be
formed which peripherally surrounds the sheet-like substrate. It is
extremely difficult for liquid to escape such a surrounding air jet
form, so efficient drying can be achieved.
[0034] In a refinement, the upper air jet and the lower air jet are
oriented such that they make contact with the sheet-like substrate
offset to each other in the transport direction by a value between
1 mm and 5 mm. Preferably, said value is between 1 mm and 3 mm, and
particularly preferably 2 mm. As already explained in connection
with the drying device, in this way, in applications in which the
sheet-like substrates have a tendency to form vibrations, this
vibration tendency may be countered and the associated risk of
breakage reduced or even eliminated. In practice, it has proved
suitable to orient the upper and lower air jets such that the upper
air jet is offset relative to the lower air jet downstream in the
transport direction when it makes contact with the sheet-like
substrate.
[0035] Advantageously, the upper and lower air jet make contact
with a rear edge of the sheet-like substrate in contact flow
directions which are obliquely angled, such that the rear edge
encloses an angle of 3.degree. or more with the inflow direction of
the upper air jet and also with the inflow direction of the lower
air jet. Preferably, said angles amount to less than 15.degree. and
are greater than or equal to 3.degree.. Particularly preferably,
the angles amount to 3.degree.. As already explained above, in this
way, in the case of liquids with a tendency to adhere to edges, a
more efficient drying can be achieved. Because of the contact flow
direction described, which runs obliquely relative to the rear
edge, the liquid may be dispelled from one end of the rear edge to
the other end where it is largely or completely detached. Also, in
corresponding applications, the tendency of sheet-like substrates
to form vibrations may be countered. The contact flow directions of
the upper and lower air jets may in principle vary with respect to
the angle enclosed with the rear edge; preferably however, the same
angular value is selected.
[0036] In an advantageous embodiment variant, several upper and
several lower air jets flow onto the sheet-like substrate, wherein
in each case one upper and one lower air jet form an air jet pair,
and the air jets of the different air jet pairs are offset relative
to each other in the transport direction when they make contact
with the sheet-like substrate. In this way, the drying effect can
be improved if required.
[0037] If there is a need to stabilize the sheet-like substrate, in
particular to avoid vibrations and the associated risk of breakage,
then preferably, in order to stabilize the sheet-like substrate, an
upper stabilizing air jet flows onto the top side and a lower
stabilizing air jet flows onto the underside. The lower stabilizing
air jet preferably has a flow direction which is oriented opposite
a flow direction of the upper stabilizing air jet. This measure may
be carried out alternatively or additionally to other steps serving
to avoid vibrations of the sheet-like substrate. The flow
directions of the stabilizing air jets may particularly preferably
be selected parallel to a surface normal of the transport
plane.
[0038] An advantageous refinement provides that the upper
stabilizing air jet forms a jet profile which runs contrary to a
jet profile of the lower stabilizing air jet. The term "contrary
jet profile" means the following: the jet profiles of the upper and
lower stabilizing air jets are configured such that, in the case of
contact of the upper stabilizing air jet onto the lower stabilizing
air jet with opposing flow direction, on a projection of the jet
profiles in the flow direction, the resulting intersection point
lies in a projection image of the two jet profiles. Preferably,
this intersection point lies approximately in the middle of the
projection image. Particularly preferably, the jet profiles are
formed to be axially symmetrical to an axis running through the
intersection point. In this way, by air inflow onto comparatively
small surface regions of the sheet-like substrate, a good
stabilizing effect can be achieved.
[0039] Preferably, during drying of the sheet-like substrate, the
sheet-like substrates are transported through the continuous system
with a speed of more than 2.6 m/minute. In this way, good and
reliable drying results can be achieved with a comparatively high
throughput rate.
[0040] The invention is now described in more detail below with
reference to figures. Where suitable, elements with the same
function carry the same reference signs. The invention is not
restricted to the exemplary embodiments shown in the figures,
including in relation to functional features. The above description
and the following description of the figures contain numerous
features, which in some cases have been combined into groups in the
dependent subclaims. These features, as all other features
disclosed above and in the figure description below, may however be
considered individually by the person skilled in the art and
combined into suitable further combinations. In particular, all
said features may be used both individually and combined into any
suitable combination with the drying device and/or the method of
the independent claims. The drawings show:
[0041] FIG. 1 a first exemplary embodiment of a drying device,
[0042] FIG. 2 a partial depiction of the drying device from FIG.
1,
[0043] FIG. 3 a partial depiction of a drying head from FIG. 2,
[0044] FIG. 4 a partial depiction of the drying device in FIG. 1
during continuous passage of a semiconductor substrate,
[0045] FIG. 5 (a) a partial sectional depiction, (b) a sectional
depiction and (c) a detail depiction of a drying head from FIG.
1,
[0046] FIG. 6 a drying head of the drying device from FIG. 1 with
the cover removed,
[0047] FIG. 7 perspective views of a second exemplary
[0048] FIG. 8 a partial depiction of the drying device from FIG.
7,
[0049] FIG. 9 a third exemplary embodiment of the drying
device,
[0050] FIG. 10 a partial depiction of a drying head from FIG.
9,
[0051] FIG. 11 a first perspective depiction of a drying head pair
from FIG. 9,
[0052] FIG. 12 a second perspective depiction of the drying head
pair from FIG. 11,
[0053] FIG. 13 a principle depiction of a first exemplary
embodiment of the method,
[0054] FIG. 14 a principle depiction of a second exemplary
embodiment of the method,
[0055] FIG. 15 a third exemplary embodiment of the method,
[0056] FIG. 16 contrary jet profiles.
[0057] FIG. 1 shows a first exemplary embodiment of the drying
device. The drying device 1 depicted therein has two upper drying
heads 2a, 2b and two lower drying heads 3a, 3b. The upper drying
head 2a and the lower drying head 3a on one side, and the upper
drying head 2b and the lower drying head 3b on the other, are
connected into respective drying head pairs. The drying device 1 is
explained in more detail below with reference to FIGS. 1 to 6. FIG.
2 shows the two lower drying heads 3a, 3b in perspective view. This
depiction shows the air outlet slots 5a, 5b which are arranged in
the lower drying heads 3a, 3b. The air outlet slot 5a is also shown
in the enlarged partial depiction of the lower drying head 3a in
FIG. 3, and in FIG. 4.
[0058] FIG. 4 also shows a semiconductor substrate which is
transported straight through the drying device 1 in a transport
direction 9. An underside of the semiconductor substrate runs in a
transport plane 8. The upper drying head 2a is only partly shown in
the depiction of FIG. 4 for the sake of clarity. The figure however
shows an upper air outlet slot 4a. FIGS. 1 and 4 thus show that the
upper drying heads 2a, 2b are arranged above the transport plane 8,
while the lower drying heads 3a, 3b are arranged below the
transport plane 8. As FIG. 2 shows, the lower drying heads 3a, 3b
have several air outlet slots 5a, 5b. The upper drying heads also
have several air outlet slots.
[0059] Longitudinal directions of all air outlet slots extend
parallel to the transport plane 8 and transversely to the transport
direction 9, as shown in FIG. 4. Openings of the air outlet slots
4a, 4b, 5a, 5b run in respective slot planes and span these. A slot
plane 11 belonging to the air outlet slot 4a of the upper drying
head 2a is indicated diagrammatically in FIG. 4. This slot plane 11
intersects the transport plane 8 at an angle a. This angle a is
greater than 0.degree. and also less than 90.degree.. Preferably it
amounts to 70.degree.. As evident from FIG. 4, the same angular
conditions prevail for the slot plane belonging to the lower air
outlet slot 5a.
[0060] FIG. 5a) shows in a partial depiction an underside view of
the upper drying head 2b. FIG. 5b) shows a sectional depiction
through this upper drying head 2b along line C-C from FIG. 5a). As
can be seen, a cover 20, which is shown in FIGS. 1 and 3 and
provided for all drying heads, is not taken into account in the
depictions of FIG. 5. FIG. 5 therefore shows the upper drying head
2b with the cover 20 removed.
[0061] The air outlet slots 4a, 4b, 5a, 5b in the drying device 1
all have a uniform slot depth 13 (see FIG. 4) which is 3 mm. A
detail depiction of the partial region Z from FIG. 5b) (shown in
FIG. 5c)), illustrates a slot width 14. This amounts to a uniform
0.5 mm. It has been found that a constant slot cross-section has
considerable influence on the drying result. In order to stabilize
the form and hence the cross-sections of the air outlet slots 5a,
5b, 4a, 4b, therefore reinforcing webs 16 are provided in the
drying device 1. These are arranged with a mutual spacing of around
5 cm. In this way, the dimensional stability of the air outlet
slots 4a, 4b, 5a, 5b may be increased.
[0062] As evident from FIGS. 2 to 6, the longitudinal directions of
the air outlet slots 4a, 4b, 5a, 5b thus extend transversely to the
transport direction 9, such that said longitudinal directions
deviate from the transport direction by an angle b which amounts to
87.degree. or less. In the case of the drying device 1, it amounts
to 87.degree.. Consequently, the angle (90.degree.-b) shown in FIG.
5a) amounts to 3.degree..
[0063] The drying device 1 is a drying device for a multitrack
system, more precisely for a five-track system. The semiconductor
substrates 7 may pass through the drying device in five tracks next
to each other. The air outlet slots 4a, 4b, 5a, 5b are provided for
each track. A slot length 15 of the air outlet slots 4a, 4b, 5a, 5b
extends over the entire width of the semiconductor substrate (see
FIG. 4). In the case of silicon semiconductor substrates, a slot
length 15 of 180 mm has proved suitable.
[0064] The upper drying head 2a and the lower drying head 3a are
arranged above each other such that the slot plane 11 forms an
intersection line with the transport plane 8 which coincides with
an intersection line formed with the transport plane 8 by the slot
plane belonging to the lower air outlet slot 5a. As a result, over
its entire length, an air jet emerging from the upper air outlet
slot 4a meets an air jet emerging from the lower air outlet slot 5a
in the transport plane 8. The same applies to the upper drying head
2b and lower drying head 3b, and the air outlet slots 4b, 5b
arranged therein.
[0065] All drying heads 2a, 2b, 3a, 3b have base plates 18a, 18b,
19a, 19b, in each of which a pocket 22 for air guidance has been
machined. This is shown as an example in FIG. 6 for the lower
drying head 3a, which to this end is depicted there with the cover
20 removed. When the cover 20 is mounted, the pocket 22 forms a
cavity 23 which serves for air guidance. In the interests of a
uniform drying result across the various tracks of the drying
device, an even flow distribution in the drying heads 2a, 2b, 3a,
3b must be ensured. To this end, an angled plate 24, which has hole
bores 25 for even air distribution, is inserted in each drying head
2a, 2b, 3a, 3b. In addition, the angled plate 24 serves to stiffen
the drying head 3a.
[0066] In the case of the drying device 1, the upper drying heads
2a, 2b are connected together by means of a common upper pipe
supply line 26. Accordingly, the lower drying heads 3a, 3b are
connected together by means of a common lower pipe supply line 27.
Air or another gas mixture used for drying is supplied to the
drying device 1 via said pipe supply lines 26, 27.
[0067] FIGS. 7 and 8 illustrate a further exemplary embodiment of
the drying device. FIG. 7 shows two perspective depictions of the
drying device 40 from different viewing angles. As in the case of
the drying device 1, the drying device 40 has two upper drying
heads 42a, 42b and two lower drying heads 43a, 43b, which form two
drying head pairs 42a, 43a and 42b, 43b. Instead of the upper and
lower pipe supply lines 26, 27 in the drying device 1, separate
hose supply lines 51a, 51, 51c, 51d are provided for each drying
head 42a, 42b, 43a, 43b in the drying device 40. They serve
correspondingly for the supply of air or another drying medium.
[0068] In the same way as in the case of the drying device 1, each
of the drying heads 42a, 42b, 43a, 43b has a base plate 48a, 48b,
49a, 49b in which a pocket is machined which can be closed by means
of a cover 20. However, in the case of the drying device 40, an
angled plate 54 serving for stiffening is not arranged in the
pockets but is attached externally to the drying heads 42a, 42b,
43a, 43b. This may prevent metallic contamination, originating in
the angled plates, from reaching the semiconductor substrates by
means of air flowing through the pockets, and contaminating these
substrates.
[0069] In contrast to the drying device 1, continuous air outlet
slots 45a, 45b are provided in the drying device 40. As shown in
FIG. 8, these extend substantially perpendicularly to the transport
direction 9.
[0070] The drying device 40 may however be used in multitrack
systems. In the upper drying heads 42a, 42b, correspondingly
designed air outlet slots are provided. However, they are arranged
offset relative to the air outlet slots 45a, 45b of the lower
drying heads 43a, 43b. When viewing the slot planes in which the
air outlet slots of the upper drying heads 42a, 42b run, and first
intersection lines which these form with the transport plane 8,
running in the same way as in the case of the drying device 1,
these first intersection lines no longer coincide with second
intersection lines formed with the transport plane 8 by the slot
planes in which the air outlet slots 45a, 45b of the lower drying
heads 43a, 43b run. Rather, for each drying head pair 42a, 43a or
42b, 43b, the first intersection line is offset in the transport
direction relative to the second intersection line. Air jets
originating from the upper drying heads 42a, 42b thus, in the
respective drying head pair, make contact with the semiconductor
substrate 7 opposite air jets from the air outlet slots 45a, 45b of
the lower drying heads 43a, 43b with an offset in the transport
direction. As explained in more detail above, in this way in
certain applications, it is possible to reduce the formation of
vibrations of the semiconductor substrate during the drying process
and the associated risk of breakage.
[0071] FIGS. 9 to 12 illustrate a further exemplary embodiment of
the drying device. The drying device 70 shown here again has two
upper drying heads 72a, 72b and two lower drying heads 73a, 73b. As
in the case of the drying device 40, continuous or at least
approximately continuous air outlet slots 74a, 75a are arranged in
the drying heads 72a, 72b, 73a, 73b, wherein the longitudinal
directions of said slots extend substantially perpendicularly to
the transport direction 9. In contrast to the drying device 40, in
the drying device 70, the air outlet slots 74a, 75a of the upper
drying heads 72a, 72b and lower drying heads 73a, 73b again lie
above each other. Accordingly, an air jet originating from the air
outlet slot 74a arranged in the upper drying head 72a, in the same
way as in the case of the drying device 1, meets an air jet
originating from the air outlet slot 75a of the lower drying head
73a in the transport plane 8.
[0072] However, the upper 72a and lower drying heads 73a of the
drying head pair shown in FIGS. 11 and 12 have stabilizing slots
80a, 81a, through which air--or more precisely the drying
medium--may flow. These are arranged offset in the transport
direction 9 next to the air outlet slots 74a or 75a. The
longitudinal directions of the stabilizing slots 80a, 81a extend
parallel to the transport plane 8 and transversely to the transport
direction 9 at an angle deviating from 90.degree.. As a comparison
of the partial depictions of FIGS. 11 and 12 shows, the stabilizing
slots 80a in the upper drying head 72a are arranged contrary to the
stabilizing slots 81a in the lower drying head 73a. In the case of
the drying device 70, the stabilizing slots 80a, 81a are formed
such that air emerging therefrom makes contact with the
semiconductor substrate in a direction parallel to a surface normal
of the transport plane 8. The stabilizing slots 80a, 81a are
provided correspondingly in the drying heads 72b, 73b. As explained
above, they may be used additionally or alternatively as means for
reducing or avoiding vibrations of the semiconductor substrates to
be dried.
[0073] As shown in FIGS. 10 to 12, the drying heads 72a, 72b, 73a,
73b have base plates 78a, 79a with pockets 82 formed therein and
covers 20, in the same way as in the drying devices 1 and 40. The
angled plate 54 serving for stiffening is mounted outside the
pockets 82, as in the case of the drying device 40. Accordingly, no
hole bores can be arranged in the angled plate 54 for distribution
of the air into the pockets 82 over the various tracks, with
associated air outlet slots 74a, 75a. The substantial and even
distribution of the air flow within the pockets 82a, which is
necessary for an even drying result over all tracks, must therefore
be achieved in another fashion. To this end, cut-outs 84 are
arranged in the webs 85 of the base plate 78a, 79a of the drying
heads 72a, 72b, 73a, 73b. By means of these cut-outs 84 in the webs
85, an even distribution of air onto the different tracks can be
achieved.
[0074] FIG. 13 illustrates in a diagrammatic depiction a first
exemplary embodiment of the method. Here, an upper air jet 92,
which extends over the entire width of the semiconductor substrate
7, flows onto a top side 28 of the semiconductor substrate 7. At
the same time, a lower air jet 93, which extends over the entire
width of the semiconductor substrate 7, flows onto an underside 29
of the semiconductor substrate 7. Said air jets 92, 93 thus flow
onto the top side 28 and the underside 29 opposite the transport
direction 9. The contact takes place at an angle a which is
preferably 70.degree.. The upper 92 and lower air jet 93 are
oriented such that they meet in mutually opposing regions of the
top side 28 firstly and the underside 29 secondly.
[0075] The first exemplary embodiment of the method may be carried
out advantageously with the drying device 1 or the drying device
70.
[0076] A refinement of the method depicted diagrammatically in FIG.
13 is explained below with reference back to FIG. 4. In this
refinement, the upper 92 and lower air jet 93 flow onto a rear edge
6 of the semiconductor substrate in flow directions which are
oriented obliquely, such that the rear edge 6 encloses an angle c
of 3.degree. with the inflow direction of the upper air jet 92 and
also with the inflow direction of the lower air jet 93. The angle c
is directly linked to the angle b depicted in FIG. 4. For this,
c=90.degree.-b.
[0077] FIG. 14 illustrates a second exemplary embodiment of the
method. Here, the upper air jet 92 and the lower air jet 93 are
oriented such that they make contact with the semiconductor
substrate 7 offset to each other by an offset 94 in the transport
direction. The offset 94 preferably amounts to 2 mm. The upper air
jet 92 makes contact with the semiconductor substrate 7 offset
downstream in the transport direction 9 relative to the lower air
jet 93. This has proved successful in practice.
[0078] The exemplary embodiment of the method illustrated in FIG.
14 may be implemented with the drying device 40.
[0079] A further exemplary embodiment of the method is illustrated
in FIG. 15. Here, an upper stabilizing air jet 96 flows onto the
top side 28 of the semiconductor substrate, and a lower stabilizing
air jet 97 flows onto the underside 29. As shown in FIG. 15, the
flow directions of the upper stabilizing air jet 96 and lower
stabilizing air jet 97 are oriented in opposite directions. Also,
the flow directions of the two stabilizing air jets 96, 97 run
parallel to a surface normal of the transport plane 8. The
stabilizing air jets 96, 97 may again be used additionally or
alternatively to reduce or avoid vibrations of the semiconductor
substrate.
[0080] FIG. 16 shows in a diagrammatic depiction a jet profile 98
of the upper stabilizing air jet 96 from FIG. 15, and a jet profile
99 of the lower stabilizing air jet 97 from FIG. 15. As can be seen
in FIG. 16, these jet profiles 98, 99 are contrary.
[0081] The exemplary embodiment of FIGS. 15 and 16 may be
implemented by means of the drying device 70.
[0082] Although the invention has been illustrated and described in
detail with reference to preferred exemplary embodiments, the
invention is not restricted by the exemplary embodiments disclosed,
and other variants of the invention may be derived by the person
skilled in the art without deviating from the basic concept of the
invention.
LIST OF REFERENCE SIGNS
[0083] 1 Drying device [0084] 2a, 2b Upper drying head [0085] 3a,
3b Lower drying head [0086] 4a, 4b Air outlet slot [0087] 5a, 4b
Air outlet slot [0088] 6 Rear edge [0089] 7 Semiconductor substrate
[0090] 8 Transport plane [0091] 9 Transport direction [0092] 11
Slot plane [0093] 13 Slot depth [0094] 14 Slot width [0095] 15 Slot
length [0096] 16 Reinforcing web [0097] 18a, 18b Base plate [0098]
19a, 19b Base plate [0099] 20 Cover [0100] 22 Pocket [0101] 23
Cavity [0102] 24 Angled plate [0103] 25 Hole bore [0104] 26 Upper
pipe supply line [0105] 27 Lower pipe supply line [0106] 28 Top
side [0107] 29 Underside [0108] 40 Drying device [0109] 42a, 42b
Upper drying head [0110] 43a, 43b Lower drying head [0111] 45a, 45b
Air outlet slot [0112] 48a, 48b Base plate [0113] 49a, 49b Base
plate [0114] 51a, 51b Hose supply line [0115] 51c, 51d Hose supply
line [0116] 54 Angled plate [0117] 70 Drying device [0118] 72a, 72b
Upper drying head [0119] 73a, 73b Lower drying head [0120] 74a Air
outlet slot [0121] 75a Air outlet slot [0122] 78a Base plate [0123]
79a Base plate [0124] 80a Stabilizing slot [0125] 81a Stabilizing
slot [0126] 82 Pocket [0127] 84 Cut-out [0128] 85 Web [0129] 92
Upper air jet [0130] 93 Lower air jet [0131] 94 Offset [0132] 96
Upper stabilizing air jet [0133] 97 Lower stabilizing air jet
[0134] 98 Jet profile of upper stabilizing air jet [0135] 99 Jet
profile of lower stabilizing air jet [0136] a Angle [0137] b Angle
[0138] c Angle [0139] C-C Section line [0140] Z Partial region
* * * * *