Information
-
Patent Grant
-
6622335
-
Patent Number
6,622,335
-
Date Filed
Wednesday, March 29, 200024 years ago
-
Date Issued
Tuesday, September 23, 200320 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 015 77
- 015 883
- 134 902
- 239 550
- 239 589
- 239 596
- 239 601
- 239 DIG 19
-
International Classifications
-
Abstract
A drip manifold having drip nozzles configured to form controlled droplets is provided for use in wafer cleaning systems. The drip manifold includes a plurality of drip nozzles that are secured to the drip manifold. Each of the plurality of drip nozzles has a passage defined between a first end and a second end. A sapphire orifice is defined within the passage and is located at the first end of the drip nozzle. The sapphire orifice is angled to produce a fluid stream that is reflected within the passage and toward the second end to form one or more uniform drops over a brush.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to semiconductor wafer cleaning and, more particularly, to techniques for applying fluids over a cleaning brush and improving wafer cleaning throughput and efficiency.
2. Description of the Related Art
In the semiconductor chip fabrication process, it is well-known that there is a need to clean a wafer where a fabrication operation has been performed that leaves unwanted residuals on the surface of the wafer. Examples of such a fabrication operation include plasma etching (e.g., tungsten etch back (WEB)) and chemical mechanical polishing (CMP). If left on the surface of the wafer for subsequent fabrication operations, the unwanted residual material and particles may cause, among other things, defects such as scratches on the wafer surface and inappropriate interactions between metallization features. In some cases, such defects may cause devices on the wafer to become inoperable. In order to avoid the undue costs of discarding wafers having inoperable devices, it is therefore necessary to clean the wafer adequately yet efficiently after fabrication operations that leave unwanted residue on the surface of the wafer.
FIG. 1A
shows a high level schematic diagram of a wafer cleaning system
50
. The cleaning system
50
typically includes a load station
10
where a plurality of wafers in a cassette
14
may be inserted for cleaning through the system. Once the wafers are inserted into the load station
10
, a wafer
12
may be taken from the cassette
14
and moved into a brush station one
16
a
, where the wafer
12
is scrubbed with selected chemicals and water (e.g., de-ionized (DI) water). The wafer
12
is then moved to a brush station two
16
b
. After the wafer has been scrubbed in brush station
16
, the wafer is moved into a spin, rinse, and dry (SRD) station
20
where DI water is sprayed onto the surface of the wafer and spun to dry. During the rinsing operation in the SRD station, the wafer rotates at about 100 rotations per minute or more. After the wafer has been placed through the SRD station
20
, the wafer is moved to an unload station
22
.
FIG. 1B
shows a simplified view of a cleaning process performed in a brush station
16
. In brush station
16
, the wafer
12
is inserted between a top brush
30
a
and a bottom brush
30
b
with top surface
12
a
facing up. The wafer
12
is capable of being rotated with rollers (not shown) to enable the rotating brushes
30
a
and
30
b
to adequately clean the entire top and bottom surfaces of the wafer
12
. In certain circumstances, the bottom surface of the wafer is required to be cleaned as well because contaminants from the bottom may migrate to the top surface
12
a
. Although both the top surface
12
a
and the bottom surface of the wafer
12
are scrubbed with the brushes
30
, the top surface
12
a
that is scrubbed with the top brush
30
a
is the primary surface targeted for cleaning, since the top surface
12
a
is where the integrated circuit devices are being fabricated. To more effectively clean the wafer
12
, a cleaning solution can be applied onto the top brush
30
a
by the use of a drip manifold
13
a
. In this example, the drip manifold
13
a
is attached to a drip control
13
which is in turn connected to a fluid source
24
. The fluid source
24
pumps fluid (e.g., any cleaning chemical or DI water) through the fluid control
13
which controls the amount of fluid entering the drip manifold
13
a
. After receiving the fluid from the fluid control
13
, the drip manifold
13
a
then expels a non-uniform drip
32
onto the top brush
30
a
. As will be discussed below, this non-uniform drip
32
has been observed to cause problems in cleaning operations.
FIG. 1C
shows a cross sectional view of the elements depicted in FIG.
1
B. When the wafer
12
has been placed on the bottom brush
30
b
, the top brush
30
a
is lowered onto the wafer
12
. As the top brush
30
a
is lowered onto the wafer
12
, drip control
13
starts the flow of fluid to the drip manifold
13
a
which releases the non-uniform drip onto the top brush
30
a
. During this time, both the bottom brush
30
a
and
30
b
turn to create the mechanical scrubbing action.
FIG. 1D
shows a more detailed side view of the wafer cleaning structure depicted in FIG.
1
B. In general, it is a goal to have the fluid provided to the drip manifold
13
a
expel “droplets” of fluid evenly over the entire length of the brush
32
a
. To do this, it is common practice to introduce the fluid into the drip manifold
13
a
at reduced flow rates and pressures. To accomplish this, the fluid source
24
supplies the cleaning fluid through the drip control
13
which regulates the amount of fluid injected into a near end
3
la of the drip manifold
13
a
. Unfortunately, as the fluid enters into the near end
31
a
, the fluid tends to flow out of the drip manifold faster at that end than at a far end
31
b
. This differential fluid expulsion occurs because most of the fluid is released through the drip holes at the near end
31
a
before the fluid can reach the drip holes at the far end
31
b
. Therefore, if the drip manifold
13
a
were totally horizontal, more near end drops
32
a
will be expelled than far end drops
32
b
. In the prior art, the drip manifold
13
a
was sometimes tilted downward slightly at a manifold angle Ø
42
to allow more fluid to reach the far end
31
b
. The manifold angle
42
is determined by finding the optimal angle of the drip manifold
13
a
which produces the equivalent amount of drip from both the near end
31
a
and the far end
31
b
. This manifold angle
42
is measured relative to a y-axis
40
a
and an x-axis
40
b
. As the drip manifold
13
a
expels the far end drops
32
a
and near end drops
32
b
onto the top brush
30
a
, the brushes
30
turn to scrub the wafer
12
.
Unfortunately, calibrating the drip manifold
13
a
to produce the right amount of fluid flow can be a very time consuming and a difficult process. By guesswork and trial and error, numerous manifold angles Ø
42
must be tried to find the optimal flow rate of the cleaning fluid. Even after the optimal flow rate has been found, the drip manifold may need re-calibrating every time the cleaning apparatus is moved to another location. This problem occurs because each different location (even a different section of the same room) can have a floor angle that is different from the previous location. Therefore, as is often the case, if the cleaning apparatus must be moved frequently, the need for constant re-calibration can create large wastes of time and reduce wafer cleaning throughput. In addition, further problems in the maintenance of manifold angle Ø
42
may occur if the drip manifold is moved by a bump or nudging of the cleaning apparatus because even a slight movement of the drip manifold can have the effect of altering the manifold angle Ø
42
. Therefore, the prior art drip manifold
13
a
must often be re-calibrated far more often than is desirable or practical.
FIG. 1E
depicts a more detailed cross-sectional view of the drip manifold
13
a
which is expelling the non-uniform drip
32
through a drip hole
13
b
. As is common practice, the drip hole
13
b
is formed by drilling a hole into the drip manifold
13
a
. Unfortunately, the drilling process is known to leave hole shavings
13
c
in and around the drip holes
13
b
. These shavings can potentially be introduced over wafers as particulates causing damage to circuits or retard the flow of fluid, thus causing un-even fluid sprays along the drip manifold
13
a
. To compensate for potential hole shavings
13
c
and un-even fluid delivery, it is common practice to deliver fluids to the drip manifold
13
a
at high pressures and flow rates. This is believed to improve the distribution of fluid out of all of the drip holes
13
b
along the drip manifold
13
a
. As consequence, however, this high pressure delivery and flows tend to produce high pressure jets
32
′.
Although the distribution of fluids out of the drip holes
13
b
improved, the high pressure jets
32
′ have the disadvantageous effects of damaging the delicate surface of the brush
32
a
. In some cases, after relatively few cleaning operations, it was noticed that the brush
32
a
became somewhat shredded or frayed. Consequently, the solution of simply increasing fluid delivery flow and pressures caused additional problems beyond those of un-even fluid delivery.
Because of these inherent problems in the present drip manifold
13
a
, additional devices such as pressure regulators, pressure gauges, and flow meters, which are part of the drip control
13
, have been used in a largely unsuccessful attempt to prevent over spraying. Unfortunately, even with seemingly proper drip control, unforeseen fluctuations in fluid pressure can occur which may result in the high pressure jet
32
′ which have been known to damage the top brush
30
a
and/or the wafer
12
.
It should be apparent that using the aforementioned drip manifold is unduly inefficient. Such a drip manifold has the downside of taking more time to setup, and requiring a large amount of maintenance time to keep the drip manifold at the perfect manifold angle Ø
42
. Moreover, the fluid application must be carefully monitored because of the possible damage to brushes and wafers caused by flow altering effects of fluctuations in fluid pressure and hole shavings
13
c
. Therefore, using prior art dripping mechanisms can cause lower throughput of wafer cleaning and/or cause damage to the brushes and wafers.
In view of the foregoing, there is a need for a drip manifold that avoids the problems of the prior art by improving cleaning fluid dripping and increasing wafer cleaning efficiency and output.
SUMMARY OF THE INVENTION
Broadly speaking, the present invention fills these needs by providing an improved method for providing uniform chemical delivery over brushes of a wafer cleaning system. It should be appreciated that the present invention can be implemented in numerous ways, including as a process, an apparatus, a system, a device, or a method. Several inventive embodiments of the present invention are described below.
In one embodiment, a drip manifold for use in wafer cleaning operations is disclosed. The drip manifold has a plurality of drip nozzles that are secured to the drip manifold. Each of the plurality of drip nozzles has a passage defined between a first end and a second end. A sapphire orifice is defined within that passage and is located at the first end of the drip nozzle. The sapphire orifice is angled to produce a fluid stream into the passage and is reflected toward the second end to form one or more uniform drops over a brush.
In another embodiment, a drip manifold for use in wafer cleaning operations is disclosed. A cleaning station having a first and second brush is provided. The drip manifold extends over the length of the first brush. A plurality of drip nozzles are secured to the drip manifold. Each of the plurality drip nozzles are spaced apart from one another and distributed over the length of the drip manifold. Each of the drip nozzles has a passage defined between a first end and a second end. A sapphire orifice is defined within that passage and is located at the first end of the drip nozzle. The sapphire orifice is angled to produce a fluid stream into the passage and is reflected toward the second end to form one or more uniform drops over the first brush.
In yet another embodiment, a method for making a drip nozzle for use in wafer cleaning operations is disclosed. The method includes generating a tubular segment having a first end and a second end. The method further includes defining a passage between the first end and the second end and inserting a sapphire orifice into the passage of the tubular segment at the first end. The method of making the drip nozzle also includes inserting the sapphire orifice into the passage at an angle and configuring the angle such that a fluid flow can be introduced from the first end through the sapphire orifice into the passage of the tubular segment, with the fluid flow exiting the second end as one or more uniform droplets.
The advantages of the present invention are numerous. Most notably, by designing a drip manifold which produces consistent dripping of uniform drops, the wafer cleaning efficiency and throughput may be improved. The claimed invention removes the problems of variable cleaning chemical flow which causes problems such as brush and/or wafer damage.
The present drip manifold does not have to be oriented at a specific manifold angle to properly apply the cleaning fluid in the proper manner. This advancement obviates the need for continual re-calibrations of drip manifold systems to obtain and maintain the perfect manifold angle. This feature reduces time spent on maintaining the drip manifold and allows increased wafer cleaning throughput. Moreover, the present drip manifold is nearly immune to fluctuations in cleaning fluid dripped caused by small fluid pressure variations. Further, due to the design of the drip nozzle, flow alterations normally caused by hole shavings are also eliminated. Therefore the drip manifold will allow new drip systems to more easily produce and maintain the type of dripping preferable in the wafer cleaning process.
Other aspects and advantages of the invention will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principle invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings. To facilitate this description, like reference numerals designate like structural elements.
FIG. 1A
shows a high level schematic diagram of a wafer cleaning system.
FIG. 1B
shows a simplified view of a cleaning process performed in a brush station.
FIG. 1C
shows a cross sectional view of the elements depicted in FIG.
1
B.
FIG. 1D
shows a more detailed side view of the wafer cleaning structure depicted in FIG.
1
B.
FIG. 1E
depicts a more detailed cross-sectional view of the drip manifold which is expelling the non-uniform drip through a hole.
FIGS. 2A and 2B
show a side view and a top view, respectively, of a cleaning system, in accordance with one embodiment of the present invention.
FIG. 3A
shows a cross-sectional view of a drip nozzle, in accordance with one embodiment of the present invention.
FIG. 3B
depicts a cross-sectional view of a drip manifold in accordance with one embodiment of the present invention.
FIG. 3C
shows an exploded view of the sapphire orifice manifold in accordance with one embodiment of the present invention.
FIG. 3D
shows a view of an alternative orifice in accordance with one embodiment of the present invention.
FIG. 4
depicts a side view of the drip manifold containing a plurality of the drip nozzles in accordance with one embodiment of the present invention.
FIG. 5
illustrates a cleaning system using the drip manifold containing a plurality of the drip nozzles in accordance with one embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
An invention of method and systems presenting an improved method for providing uniform chemical delivery over brushes of a wafer cleaning system. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be understood, however, by one of ordinary skill in the art, that the present invention may be practiced without some or all of these specific details. In other instances, well known process operations have not been described in detail in order not to unnecessarily obscure the present invention.
FIGS. 2A and 2B
show a side view and a top view, respectively, of a cleaning system
120
. The cleaning system
120
typically includes an input station
100
where a plurality of wafers may be inserted for cleaning through the system. Once the wafer
12
is inserted into the input station
100
, the wafer
12
may be taken from the input station
100
and moved into a brush station one
102
a
, where the wafer
12
is scrubbed with selected chemicals and water (e.g., de-ionized water) before being moved to a brush station two
102
b
. In the brush stations, a drip manifold including a drip nozzle of the present invention is contained. The features of the drip manifold and drip nozzle will be described in greater detail below.
After the wafer
12
has been scrubbed in the brush stations
102
, the wafer
12
is moved into a spin, rinse, and dry (SRD) station
104
, where de-ionized (DI) water is sprayed onto the surface of the wafer and spun to dry. After the wafer has been placed through the SRD station
104
, the wafer
12
is moved to an output station
106
. The cleaning system
120
is configured to be programmed and controlled from system electronics
108
. Of course, this cleaning system is only exemplary in nature, and any other type of cleaning system that uses brush technology coupled with drip manifolds will also benefit from the advantages of the present invention. For instance, the system can be a standalone brush station for scrubbing wafers horizontally or vertically, or part of a chemical mechanical polishing (CMP) system and clean system combination.
FIG. 3A
shows a cross-sectional view of a drip nozzle
200
, in accordance with one embodiment of the present invention. The drip nozzle
200
is configured to provide more consistent dripping of more uniform drops.
In one embodiment, the drip nozzle
200
has a first end
201
a
and a second end
201
b
. The drip nozzle
200
has a tubular segment
201
c
connected to a nozzle head
200
c
. The drip nozzle
200
contains a passageway between the first end
201
a
and the second end
201
b
where fluid can travel. Generally, a passage
205
is defined by a cylindrical shape having an inner surface
200
′. In one embodiment, the first end
201
a
of the drip nozzle
200
will preferably have an angled wall
200
a
. It should be understood that the angle of the angled wall
200
a
can be varied depending on fluid flow requirements or any other calibration parameter. The drip nozzle
200
also has an outer nozzle wall
200
b
. To secure the drip nozzle
200
to a drip manifold (as will be shown below), the outer nozzle wall will preferably have threads (not shown).
In one embodiment, a sapphire orifice
202
is preferably inserted into the angled wall
200
a
at the first end
201
a
. In an alternative embodiment, the sapphire orifice can made from any suitable material that is hard enough and compatible with cleaning solutions, and therefore, the sapphire orifice can be made from any material to define an insert orifice. Because a passage
200
″ is angled into the angled wall
200
a
, the sapphire orifice
202
is also angled to fit into the passage
200
″. Thus, the sapphire orifice
202
will include an orifice inner surface
202
′ that defines an angled path into the passage
205
. This angled path serves to create an angled fluid stream that is directed against the drip nozzle inner surface
200
′ at a stream contact surface
206
.
Although sapphire is used in an exemplary embodiment, other materials may be used such as materials that are compatible with various cleaning fluids. Such cleaning fluids may include basic solutions, acidic solutions (e.g., HF), and other fluids. The sapphire material can also be defined with passage ways (e.g., holes) that are defined to tight tolerances, and once formed, leave a very clean unobstructed surface (e.g., smooth surface). Moreover, it should be appreciated by one of ordinary skill in the art that the sapphire orifice
202
may be oriented differently as long as the resultant configuration produces an angled stream of fluid that is directed at the drip nozzle inner surface
200
′.
When orifice input fluid
204
′ first enters the drip nozzle
200
, it travels through the sapphire orifice
202
. As the resultant angled stream leaves the sapphire orifice
202
and enters the inner passage
205
of drip nozzle
200
, it begins to expand and is defined by a stream boundary
206
a
and a stream boundary
206
b
. This initial stream then hits against the stream contact surface
206
which is a section of the drip nozzle inner surface
200
′. Because the initial stream hits the stream contact surface
206
at an angle, the initial stream reflects off of the stream contact surface
206
and is angled towards the second end
201
b
of the drip nozzle
200
. When this reflection occurs, the initial stream loses velocity and expands to form a first reflected spray with a spray boundary
208
a
and a spray boundary
208
b
. When this expansion occurs, portions of the first reflected spray having boundaries
208
a
and
208
b
contact portions of the incoming initial stream having boundaries
206
a
and
206
b
. This contact serves to decrease the velocities of both the initial stream and the first reflected spray.
The first reflected spray then hits spray contact surface
208
. By this time, the first reflected spray has expanded so the area of the spray contact surface
208
is larger than the spray contact surface
206
. When this contact occurs, the first reflected spray is reflected a second time towards the second end
201
b
of the drip nozzle
200
. When the reflection occurs, the first reflected spray loses velocity and a slower moving second reflected spray is produced. This loss in velocity causes a further expansion of the spray boundaries to form a spray boundary
210
a
and a spray boundary
210
b
. As the second reflected spray expands, it comes into contact with the incoming first reflected spray. This contact further reduces the velocities of both the first reflected spray and the second reflected spray.
The second reflected spray then contacts a spray contact surface
210
. Once again, because of the expansion of the spray in transit, the spray contact surface
210
is larger than the spray contact surface
208
. When this contact occurs, the spray is once again reflected at an angle towards the second end
201
b
of the drip nozzle
200
to produce a third reflected spray. When this reflection occurs, the velocity of the spray is decreased again and further expansion of the spray occurs. This expansion forms a spray boundary
212
a
and a spray boundary
212
b
. Moreover, when this spray expansion occurs, the third reflected spray comes into contact with the incoming second reflected spray. When this contact occurs, the velocities of both the second reflected spray and the third reflected spray are decreased.
Therefore, each spray reflection produces a decrease in fluid velocity. These spray reflections continue until the fluid reaches the periphery of a nozzle head
200
c
at the second end
201
b
. By this time, the fluid velocity has slowed significantly. This decrease in velocity creates an accumulation of liquid towards the second end
201
b
of the drip nozzle
200
which creates back forces
207
in the direction of the first end
201
a
. The creation of these back forces
207
serves to further slow down the fluid traveling through the passage
205
of the drip nozzle
200
. Therefore, uniform droplets slowly form at the opening of the nozzle head
200
c
creating a controlled, consistent, and uniform dripping action.
In this example, the drip nozzle head
200
c
is configured so it is larger in circumference than the outer nozzle wall
200
b
. The nozzle head
200
c
is also preferably controlled at surface
200
c
′ of drip nozzle
200
which further assists in the production of uniform drops. For example, the diameter D
263
contributes to the formation of a uniform droplet by defining an area of attachment of the uniform droplet to the nozzle head
200
c
. The uniform droplet grows in size until its mass causes it to separate from the surface
200
c
′. In addition, an angle Ø
265
also contributes to the formation of the uniform droplet by preventing fluid from migrating up the nozzle. It should be appreciated that the drip nozzle may be configured in a variety of shapes and sizes to produce similar drops. Additionally, the drip nozzle
200
can be made without the drip nozzle head
200
c
. The actual shape of the drip nozzle
200
will primarily depend on the viscosity of fluid, drip rate, and the environment into which it is being installed. Also, the drip nozzle
200
is preferably manufactured from a material that is compatible with the chemistry of the fluid such as Teflon™ or polyethylene terephthalate (PET). PET materials are known for their high purity and are relatively easy to machine. In one embodiment, the length L
260
of the drip nozzle
200
can vary between about 0.02 inch and about 1 inch, and more preferably is about 0.437 inch long. This dimension can generally be varied to any length that will allow for one or more spray reflections off of the drip nozzle inner surface
200
′. This will ensure that a more uniform drip is formed. In this embodiment, passage diameter D
262
of the drip nozzle
200
can be between about 0.02 inch and about 0.1 inch, and more preferably is about 0.062 inch. Of course, this dimension can be varied depending on the viscosity and desired fluid flow. Still further, the sapphire orifice is preferably angled once inserted into the orifice inner surface
200
″. This angle can vary widely. For example, the angle Ø
264
can be between about 15 degrees and about 75 degrees, and more preferably is set to about 45 degrees. In general, some angle must exist so long as one or more spray reflections off of the drip nozzle inner surface
200
′ are produced.
FIG. 3B
depicts a cross-sectional view of a drip manifold
220
in accordance with another embodiment of the present invention. In this embodiment, the drip manifold
220
has a manifold inner surface
220
a
and a manifold outer surface
220
b
. The drip nozzle
200
is secured to the drip manifold
220
by threads
200
d
. It should be understood that the drip nozzle
200
may be fastened to the drip manifold
220
in a variety of other ways such as pressing the drip nozzle
200
into the drip manifold
220
. In one embodiment, the drip nozzle
200
is preferably oriented such that the first end
201
a
protrudes into an inner region
203
of the drip manifold
220
. Although any suitable diameter may be used for the inner part of the drip manifold
220
, a diameter ranging between about 0.250 inch and 1.00 inch, and more preferably about 0.375 inch may be used. By having the drip nozzle
200
extend into the inner region
203
, hole shavings
220
c
(created by the drilling of the hole) are less likely to clog the hole defined by the orifice surface
202
′. The inner region
203
of the drip manifold
220
is preferably a cylindrical shape defined by the manifold inner surface
220
a
. When the cleaning fluid is pumped into the drip manifold
220
, the inner region
203
is filled by a manifold fluid
204
. A portion of the manifold fluid
204
enters the sapphire orifice
202
as orifice input fluid
204
′. The orifice input fluid
204
′ then goes through the numerous reflective actions as described above with reference to
FIG. 3A
, and a uniform drop
204
a
is released from the nozzle head
200
c
. Of course, in a true drip manifold
220
, there will actually be several drip nozzles
200
, as will be illustrated below.
FIG. 3C
shows an exploded view of the sapphire orifice
202
. In this embodiment, the sapphire orifice
202
includes the orifice inner surface
202
′ defined generally as a cylindrical shape. At one end of the sapphire orifice
202
, the inner surface
202
′ angles out to define an angled surface
202
″. The angled surface
202
″ is configured to feed into the passage
205
of the drip nozzle
200
. Therefore, in operation, the orifice input fluid
204
′ enters the sapphire orifice
202
and exits out of one side as defined by the stream boundaries
206
a
and
206
b
. In one embodiment, it is preferable for an outer diameter D
266
of the sapphire orifice
202
to be about 0.087 inch. It should be appreciated that the diameter of the orifice inner surface
202
′ may be varied to produce different flow rates as need. The dimensions of the orifice inner surface
202
′ are closely controlled to a desired tolerance so that most all of the sapphire orifice
202
of a specific size are nearly identical. In one preferred embodiment, the orifice inner surface
202
′ may have a diameter that is about 0.010. The length L
268
of the sapphire orifice
202
in this example is about 0.047 inch. Of course, the length L
268
may be varied depending upon the desired drip characteristics.
FIG. 3D
shows a view of an alternative orifice
202
″.
In this embodiment, alternative orifice
202
″ is preferably also made out of a sapphire material. The orifice inner surface
202
′ of the alternative orifice
202
′ keeps a constant configuration and does not angle out into-the passage
205
of the drip nozzle
200
. In one embodiment, the diameter D
266
of the alternative orifice
202
″ is also about 0.087 inch. It should be appreciated that the diameter of the orifice inner surface
202
′ may be varied to produce different flow rates as needed. The dimensions of the orifice inner surface
202
′ are closely controlled to a desired tolerance so that most all of the sapphire orifice
202
of a specific size are nearly identical. In yet another embodiment, it is preferable for length L
268
of the alternative orifice
202
″ to be about 0.047 inch. The length L
268
of the alternative orifice
202
″ may be varied depending upon the drip characteristics desired. The orifice input fluid
204
′ enters the alternative orifice
202
″ and exits out of the other side as defined by the stream boundaries
206
a
and
206
b
. As mentioned above, the sapphire orifice
202
and the alternative orifice
202
″ may be made out of other materials that are compatible with different cleaning fluids and that can be defined to exact tolerances and leave a smooth surface after it is formed. The smooth surface thus enables the generation of a more uniform entry point for fluid and gives rise to more controlled droplets from each of the drip nozzles
200
that may be integrated into a drip manifold
220
.
FIG. 4
depicts a side view of the drip manifold
220
containing a plurality of the drip nozzles
200
in accordance with one embodiment of the present invention. In this embodiment, a fluid source
258
is connected by a tubing
252
to a pressure regulator
256
. A pressure gauge
254
is then attached to a portion of the tubing
252
connecting the pressure regulator
256
to one end of the drip manifold
220
. A plurality of the drip nozzles
200
are secured to the drip manifold
220
as explained above with reference to FIG.
3
B. In one embodiment, the drip manifold
220
is preferably a cylindrical structure manufactured out of a Teflon™ material or any other material that is compatible with cleaning chemicals.
In this embodiment, the fluid source
258
generally supplies fluid to the pressure regulator
256
where the pressure of the fluid leading to the drip manifold can be controlled. A pressure gauge
254
monitors the fluid pressure in the tubing
252
. By the use of both the pressure regulator
256
and the pressure gauge
254
, the fluid pressure (and the resultant dripping) of the cleaning fluids can be controlled. The fluid then passes from the tubing
252
into the drip manifold
220
. Once inside the drip manifold
220
, the pressurized fluid flows equally into a plurality of the drip nozzles
200
. Because the drip manifold
220
may be filled with pressurized fluid, the flow of fluid into all of the drip nozzles
200
is substantially equal. As described above, after the fluid has passed through the drip nozzles
200
, the uniform drops
204
a
drip from the drip nozzles
200
at a constant and controlled rate. Advantageously, the flow of fluid through the drip manifold
220
may be regulated with only the use of the pressure gauge
254
and the pressure regulator
256
without the need for implementing a a flow meter or additional hardware.
FIG. 5
illustrates a cleaning system using the drip manifold
220
containing a plurality of the drip nozzles
200
in accordance with one embodiment of the present invention. The tubing
252
is connected to one end of the drip manifold
220
. In one embodiment, the drip manifold
220
is preferably positioned over the top brush
30
a
so the cleaning fluid can be dripped onto the top brush
30
a
. It is should be appreciated that the drip manifold
220
may be positioned in any orientation which would allow for consistent application of cleaning liquid onto the top brush
30
a
(or any other brush that is positioned below the drip manifold
220
). The wafer
12
is placed on top of the bottom brush
30
b
and below the top brush
30
a
. The tubing
252
transports fluid into the drip manifold
220
. The fluid passes through the drip nozzles
200
and is released in the form of the uniform drops
204
a
. As the uniform drops
204
a
are applied to the top brush
30
a
at a consistent rate, the brushes
30
can turn thus scrubbing the wafer
12
. Therefore, the drip manifold
220
applies precisely the correct amount of cleaning fluid at the desired rate to the top brush
30
a
which results in optimal cleaning of the wafer
12
.
While this invention has been described in terms of several preferred embodiments, it will be appreciated that those skilled in the art upon reading the preceding specifications and studying the drawings will realize various alterations, additions, permutations and equivalents thereof. It is therefore intended that the present invention includes all such alterations, additions, permutations, and equivalents as fall within the true spirit and scope of the invention.
Claims
- 1. A drip manifold for use in wafer cleaning operations, comprising:a plurality of drip nozzles, each drip nozzle including, a first end and a second end and a passage defined there between; and a sapphire orifice defined within the passage and located at the first end of the drip nozzle, the passage having a wall that extends longitudinally between the first end and the second end, the sapphire orifice positioned to define an acute angle relative to the longitudinal extension of the wall, the sapphire orifice having an inner passage that is positioned in and aligned with the angle of the sapphire orifice, the inner passage of the sapphire orifice being capable of passing a fluid stream that can be reflected off the wall at least twice in a direction that is toward the second end, the fluid stream being reflected enables one or more uniform drops to exit the second end of the passage.
- 2. A drip manifold for use in wafer cleaning operations as recited in claim 1, wherein the drip manifold is integrated into a cleaning station having a first brush and a second brush; and the drip manifold extends over a length of the first brush.
- 3. A drip manifold for use in wafer cleaning operations as recited in claim 2, wherein each of the plurality of drip nozzles are spaced apart from one another and are distributed over a length of the drip manifold.
- 4. A drip manifold for use in wafer cleaning operations as recited in claim 1, wherein the first end of each of the plurality of drip nozzles protrudes into an inner region of the drip manifold.
- 5. A drip manifold for use in wafer cleaning operations as recited in claim 4, wherein the second end of each of the plurality of drip nozzles extends out beyond an outer surface of the drip manifold.
- 6. A drip manifold for use in wafer cleaning operations as recited in claim 1, wherein the first end has an angled wall, and the angled wall being configured to receive the sapphire orifice that is in the form of an insert.
- 7. A drip manifold for use in wafer cleaning operations as recited in claim 1, wherein each of the plurality of nozzles incorporate threads to enable the threading into the drip manifold.
- 8. A drip manifold for use in wafer cleaning operations as recited in claim 1, wherein each of the plurality of drip nozzles has a nozzle head at the second end.
- 9. A drip manifold for use in wafer cleaning operations as recited in claim 1, the passage defined between the first end and the second end of the drip nozzle defining a length through which the fluid stream reflects until the fluid stream forms the uniform drop.
- 10. A drip manifold for use in wafer cleaning operations as recited in claim 1, wherein at one end, the inner surface of the sapphire orifice angles out to define an angled surface, said angled surface is configured to feed into the passage defined by the first end and the second end of the drip nozzle.
- 11. A wafer cleaning apparatus, comprising:a cleaning station having a first brush and a second brush; a drip manifold extending over a length of first brush; a plurality of drip nozzles integrated into the drip manifold, each of the plurality of drip nozzles being spaced apart from one another and are distributed over the length of the drip manifold; and each drip nozzle including, a first end and a second end and a passage defined there between; a sapphire orifice defined within the passage and located at the first end of the drip nozzle, the passage having a wall that extends longitudinally between the first end and the second end, the sapphire orifice positioned to define an acute angle relative to the longitudinal extension of the wall, the sapphire orifice having an inner passage that is positioned in and aligned with the angle of the sapphire orifice, the inner passage of the insert orifice being capable of passing a fluid stream that can be reflected off the wall at least twice in a direction that is toward the second end, the fluid stream being reflected enables one or more uniform drops to exit the second end of the passage over the first brush.
- 12. A wafer cleaning apparatus as recited in claim 11, wherein the first end of each of the plurality of drip nozzles protrudes into an inner region of the drip manifold.
- 13. A wafer cleaning apparatus as recited in claim 12, wherein the second end of each of the plurality of drip nozzles extends out beyond an outer surface of the drip manifold.
- 14. A wafer cleaning apparatus as recited in claim 11, wherein the first end has an angled wall, and the angled wall being configured to receive the sapphire orifice that is in the form of an insert.
- 15. A wafer cleaning apparatus as recited in claim 11, wherein each of the plurality of nozzles incorporate threads to enable the threading into the drip manifold.
- 16. A wafer cleaning apparatus as recited in claim 11, wherein each of the plurality of drip nozzles has a nozzle head at the second end.
- 17. A wafer cleaning apparatus as recited in claim 11, the passage defined between the first end and the second end of the drip nozzle defining a length through which the fluid stream reflects until the fluid stream forms the uniform drop.
- 18. A wafer cleaning apparatus as recited in claim 11, wherein at one end, the inner surface of the sapphire orifice angles out to define an angled surface, said angled surface is configured to feed into the passage defined by the first end and the second end of the drip nozzle.
- 19. A drip manifold for use in wafer cleaning operations, comprising:a plurality of drip nozzles, each drip nozzle including, a first end and a second end and a passage defined there between; and an insert orifice defined within the passage and located at the first end of the drip nozzle, the passage having a wall that extends longitudinally between the first end and the second end, the insert orifice positioned to define an acute angle relative to the longitudinal extension of the wall, the insert orifice having an inner passage that is positioned in and aligned with the angle of the insert orifice, the inner passage of the insert orifice being capable of passing a fluid stream that s can be reflected off the wall at least twice in a direction that is toward the second end, the fluid stream being reflected enables one or more uniform drops to exit the second end of the passage.
- 20. A drip manifold for use in wafer cleaning operations as recited in claim 19, wherein the drip manifold is integrated into a cleaning station having a first brush and a second brush; and the drip manifold extends over a length of the first brush.
- 21. A drip manifold for use in wafer cleaning operations as recited in claim 20, wherein each of the plurality of drip nozzles are spaced apart from one another and are distributed over a length of the drip manifold.
- 22. A drip manifold for use in wafer cleaning operations as recited in claim 19, wherein the insert orifice is defined from one of a sapphire material and a cleaning compatible material.
US Referenced Citations (13)
Foreign Referenced Citations (4)
Number |
Date |
Country |
229370 |
Oct 1943 |
CH |
92 16 511.7 |
Feb 1993 |
DE |
1.567.272 |
May 1969 |
FR |
2 7225 11 |
Jan 1996 |
FR |