U.S. patent application number 11/217750 was filed with the patent office on 2007-03-08 for spatially-arranged chemical processing station.
Invention is credited to Igor C. Ivanov, Chiu Ting, Jonathan Weiguo Zhang.
Application Number | 20070051306 11/217750 |
Document ID | / |
Family ID | 32297597 |
Filed Date | 2007-03-08 |
United States Patent
Application |
20070051306 |
Kind Code |
A1 |
Ivanov; Igor C. ; et
al. |
March 8, 2007 |
Spatially-arranged chemical processing station
Abstract
The present invention discloses a station, e.g., for IC
fabrication with a flexible configuration. It consists of an array
of processing chambers, which are grouped into processing modules
and arranged in a two-dimensional fashion, in vertical levels and
horizontal rows, and is capable of operating independent of each
other. Each processing chamber can perform electroless deposition
and other related processing steps sequentially on a wafer with
more than one processing fluid without having to remove it from the
chamber. The system is served by a single common industrial robot,
which may have a random to access to all the working chambers and
cells of the storage unit for transporting wafers between the wafer
cassettes and inlet/outlets ports of any of the chemical processing
chambers. The station occupies a service-room floor space and a
clean-room floor space. The processing modules and the main
chemical management unit connected to the local chemical supply
unit occupy a service-room floor space, while the robot and the
wafer storage cassettes are located in a clean room. Thus, in
distinction to the known cluster-tool machines, the station of the
invention makes it possible to transfer part of the units from the
expensive clean-room area to less-expensive service area.
Inventors: |
Ivanov; Igor C.; (Dublin,
CA) ; Ting; Chiu; (Saratoga, CA) ; Zhang;
Jonathan Weiguo; (San Jose, CA) |
Correspondence
Address: |
Mollie E. Lettang;Conley Rose, P.C.
P.O. Box 684908
Austin
TX
78768-4908
US
|
Family ID: |
32297597 |
Appl. No.: |
11/217750 |
Filed: |
September 1, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10299069 |
Nov 19, 2002 |
6939403 |
|
|
11217750 |
Sep 1, 2005 |
|
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|
Current U.S.
Class: |
118/323 ;
118/300; 118/313; 118/326; 118/52; 118/66 |
Current CPC
Class: |
H01L 21/67017 20130101;
H01L 21/67173 20130101; H01L 21/67178 20130101; H01L 21/67769
20130101 |
Class at
Publication: |
118/323 ;
118/052; 118/326; 118/066; 118/313; 118/300 |
International
Class: |
B05C 13/02 20060101
B05C013/02; B05B 15/12 20060101 B05B015/12; B05B 3/00 20060101
B05B003/00; B05C 5/00 20060101 B05C005/00 |
Claims
1.-16. (canceled)
17. A chemical processing station for processing objects,
comprising: a plurality of chemical processing chambers each
comprising an opening dimensioned to allow an object to be loaded
into the processing chamber; an object handling unit configured to
load objects into the openings; and a wall separating the object
handling unit from the plurality of chemical processing chambers,
wherein the wall comprises a plurality of windows respectively
aligned with the openings of the plurality of chemical processing
chambers.
18. The chemical processing station of claim 17, wherein the object
handling unit is arranged in a clean room, and wherein the
plurality of chemical processing chambers is not arranged in a
clean room.
19. The chemical processing station of claim 17, further comprising
a chemical management system configured to supply one or more
fluids to the plurality of chemical processing chambers, wherein
the chemical management system is arranged on the same side of the
wall as the plurality of chemical processing chambers.
20. The chemical processing station of claim 19, wherein the
chemical management system comprises: a designated set of piping
coupled to each of the chemical processing chambers; and a
plurality of chemical tanks, wherein at least two designated sets
of piping are coupled to different combinations of the plurality of
chemical tanks.
21. The chemical processing station of claim 17, further comprising
a plurality of object storage units arranged parallel to the
plurality of chemical processing chambers and on the same side of
the wall as the object handling unit.
22. The chemical processing station of claim 17, wherein the
plurality of windows are arranged in array within the wall.
23. The chemical processing station of claim 17, wherein the
plurality of chemical processing chambers are arranged in arrays
such that the chemical processing chambers are arranged
horizontally and vertically adjacent to each other.
24. A chemical processing station for processing objects,
comprising: a first set of chemical processing chambers; a second
set of chemical processing chambers arranged in parallel with the
first set of chemical processing chambers; a plurality of object
storage units aligned such that objects stored therein are accessed
at a direction perpendicular to the first and second sets of
chemical processing chambers and such that a confined space is
formed between the first and second sets of chemical processing
chambers and plurality of object storage units, wherein each of the
plurality of object storage units is configured to hold a plurality
of objects; and a single object handling unit arranged within the
confined space.
25. The chemical processing station of claim 24, wherein the single
object handling unit and the plurality of object storage units are
arranged in a clean room, and wherein the first and second sets of
chemical processing chambers are not arranged in a clean room.
26. The chemical processing station of claim 24, wherein the
plurality object storage units comprise a first plurality of object
storage units arranged adjacent to one end of the first and second
sets of chemical processing chambers and a second plurality of
object storage units arranged adjacent to the other end of the
first and second sets of chemical processing chambers.
27. The chemical processing station of claim 24, further comprising
a pair of walls separating the single object handling unit from the
first and second sets of chemical processing chambers, wherein the
pair of walls comprise a plurality of windows aligned with openings
of the first and second sets of chemical processing chambers.
28. The chemical processing station of claim 24, further comprising
a chemical management unit having: a plurality of tanks for storing
processing fluids; piping coupled between the plurality of tanks
and the first and second sets of chemical processing chambers; and
a controller for directing the supply of the processing fluids from
the plurality of tanks to the first and second sets of chemical
processing chambers.
29. The chemical processing station of claim 28, wherein the
plurality of tanks comprises a first set and a second set of tanks
respectively coupled to the first set and second set of chemical
processing chambers.
30. The chemical processing station of claim 24, wherein the first
and second sets of chemical processing chambers are arranged in
arrays such that the chemical processing chambers in each set are
arranged horizontally and vertically adjacent to each other.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to semiconductor manufacturing
equipment. More particularly, the invention relates to a
spatially-arranged station for deposition from liquid media, e.g,
to an electroless deposition station that contains a plurality of
individual and independently operating chemical processing chambers
served by a common workpiece handling unit. The station of the
present invention may find use in the mass production of high
density interconnect for integrated circuits.
BACKGROUND OF THE INVENTION
[0002] In present ULSI (ultra-large-scaled-integration) structures,
high circuit speed, high packing density and low power dissipation
are essential. As a result, feature sizes must be scaled downward,
and the interconnect related time delays become the major
limitation. Elemental aluminum and its alloys have been the
traditional metals used to form lines and plugs in IC's; however,
aluminum has a relatively high resistivity and its electromigration
susceptibility can lead to the formation of voids in the metal
lines. Therefore copper has been considered as a replacement
material to aluminum in interconnect metallurgy system due to its
lower resistivity and higher reliability. Replacing current
aluminum interconnect materials by copper has become a critical
goal for semiconductor manufacturers especially for sub-quarter
micron devices.
[0003] However, there are serious problems related to process
integration of copper to integrated circuits. It is difficult to
pattern and remove copper by dry etching, because its reaction
product is not gaseous. The conventional approach of depositing a
film and then patterning it cannot be relied upon for producing
copper interconnections on substrates. Another problem lies in
copper's extremely high diffusivity in silicon dioxide, and minute
amount of diffused copper atoms in the transistors' active regions
will play havoc with their device characteristic.
[0004] To solve the above stated problems, "damascene" method has
been applied effectively, whereby a pattern of interconnection
grooves is first etched in the surface of a layer of oxide
dielectric; and the surfaces of grooves are coated first with a
thin barrier and seed layers and then filled with copper. The
unwanted copper metal on the substrate surface is then removed from
the surface by a CMP (chemical-mechanical polish) process. However,
as the width of interconnections becomes thinner, these grooves
would have a higher aspect ratio. There is great difficulties to
fill them using conventional means.
[0005] It is known that metal films can be deposited using a
variety of processes such as CVD (chemical vapor deposition), PVD
(physical vapor deposition), electroplating, and electroless
plating. Of these techniques, electroplating and electroless
plating are the most economical and promising. At present,
electroplating is the more mature technology and is being applied
in development and production of 0.18-0.13 .mu.m copper lines in IC
circuits, using exclusively the damascene method for Cu
delineation. However, it is apparent that the electroplating
technique has its limitations in further scaling down the geometry
of the device. To pre-condition an electroplating step, a thin but
continuous metallic seed layer must first be deposited on the
substrate by another method for the purpose of current conduction.
Utilization of a limited number of discrete contact with the seed
layer at the perimeter of the wafer usually produces higher current
densities at the contact points than at other portion of the wafer;
non-uniformity of voltage drop on the wafer surface in turn causes
non-uniformity in the deposits of plated material's thickness.
Although this non-uniformity can be compensated by the provision of
additional electrically conductive elements at the wafer periphery,
it adds to the complexity of equipment, and increases costs of
production.
[0006] As the geometries of the circuits are scale down further,
the sizes of such features as vias and trenches also are reduced.
As a result, it becomes more difficult to provide continuous
barrier and particularly seed layers. In addition, the thickness
ratio of the seed layers in the trenches will become
disproportional larger as compared to the copper layer thickness in
the trenches; keeping this ratio constant will aggravate the
non-uniformity of the electroplated film.
[0007] Electroless plating is a deposition process for metals on a
catalytic surface from an electrolyte solution without an external
source of current. Electroless deposition has always been processed
in a batch mode because its deposition rate is usually very low. It
has always been deposited in a big tank with multiple. work pieces
in order for the process to be economically viable.
[0008] Since single wafer and clustered system for IC processing
has become the common and prevailing trend in the IC industry, big
open tanks with processing chemicals as required by the electroless
plating process are not compatible or easily implemented in IC
fabs, and are wasteful of the expensive ultra-clean fab. space
because of their large footprint.
[0009] Both the electro- and electroless plating techniques suffer
from a common problem because their operations usually taking place
in open electrolyte baths. When wafers are transferred from the
baths to be cleaned, foreign particles tend to be deposited on the
surface of the substrate and oxidation of the catalytic surface in
the exposure to air may result in poor catalytic activity and poor
metal deposits. Another common problem is the possible occurrence
of non-wetting of deep and narrow trenches or holes in the
substrate surface because of liquid evaporation. It is more
desirable not to transfer the wafer between the process steps and
to avoid exposing the wafer to air by using a single processing
bath; and to move the different fluids for each step in the process
through the process chamber.
[0010] The above problem are being addressed by the system
described in U.S. Pat. No. 5,830,805 issued in 1998 to Y.
Shacham-Diamond, et. al. This patent discloses an electroless
deposition apparatus and method, whereby electroless deposition on
a wafer takes place in a closed process chamber. It is thus
possible to subject the wafer to more than one processing fluids
and processing steps while retaining it within the chamber. The
invention is useful for manufacturing processes that include
depositing, etching, cleaning, rinsing, and drying. The process
chamber used in the preferred embodiments of the apparatus of the
above patent is an enclosed container capable of holding one or
more semiconductor wafers. In spite of their advantages, the
embodiment for a single wafer chamber suffers from the shortcoming
of low wafer throughput and would be unsuitable for the
manufacturing environment. Their batch processing embodiment, on
the other hand would have a issue of film thickness uniformity
control within the wafer and from wafer to wafer.
[0011] U.S. Pat. No. 6,322,677 issued in 2001 to D. Woodruff, et
al. discloses a lift and rotate assembly for use in a workpiece
processing station and a method of attaching the same. The lift and
rotate assembly includes a body having a slim profile and pins
located on opposite sides for mounting the assembly onto a tool
frame. The lift and rotating assembly further includes a rotating
mechanism coupling a processing head to the body, and for rotating
the process head with respect to the body. The rotating mechanism
includes a motor, wherein the motor is located within the
processing head and the shaft of the motor is coupled to and
rotationally fixed with respect to the body. The lift and rotate
assembly further includes a lift mechanism for lifting the process
head with respect to the body. A cable assembly within the lift and
rotate assembly includes a common cable loop for feeding additional
length of cable along both the lift direction and the rotational
direction of movement. The station contains a plurality of
processing chambers arranged in two parallel rows with an object
handling unit moveable on the tracks between the rows of the
processing chambers. In order to load and unload the objects into
and from the individual processing chambers, it is necessary to
open the top cover of each chamber and to transfer the object using
the transport mechanism with a complicated trajectory of an
object-handling mechanism. Such an arrangement is purely linear and
cannot rationally use the floor space of the clean room.
[0012] U.S. Pat. No. 6,267,853 issued in 2001 to Y. Dordi, et al.
discloses an electro-chemical deposition system which generally
comprises a mainframe having a mainframe wafer transfer robot, a
loading station disposed in connection with the mainframe, one or
more processing cells disposed in connection with the mainframe,
and an electrolyte supply fluidly connected to the one or more
electrical processing cells. Preferably, the electrochemical
deposition system includes an edge bead removal/spin-rinse-dry
(EBR/SRD) station disposed on the mainframe adjacent the loading
station, a rapid thermal anneal chamber attached to the loading
station, a seed layer repair station disposed on the mainframe, and
a system controller for controlling the electrochemical deposition
process and the components of the electrochemical deposition
system. In fact, this is a cluster tool station with various
functional units arranged around a common object transfer mechanism
for transferring objects between various functional units in
accordance with a required sequence. A disadvantage of the
aforementioned arrangement that the entire cluster machine can be
placed into the clean room only as an indivisible or integral
system which does not allow placement of those units which
otherwise could be placed into a service area beyond the boundaries
of the expensive clean-room floor space.
[0013] The same disadvantages as in Dordi's, et al. invention are
inherent in the substrate plating apparatus disclosed in U.S. Pat.
No. 6,294,059 issued in 2001 to A. Hongo, et al. The apparatus
includes a plating unit for forming a plated layer on a surface of
the substrate including the interconnection region, a chemical
mechanical polishing unit for chemically mechanically polishing the
substrate to remove the plated layer from the surface of the
substrate leaving a portion of the plated layer in the
interconnection region, a cleaning unit for cleaning the substrate
after the plated layer is formed or the substrate is chemically
mechanically polished, a drying unit for drying the substrate after
the substrate is cleaned, and a substrate transfer unit for
transferring the substrate to and from each of the first plating
unit, the first chemical mechanical polishing unit, the cleaning
unit, and the drying unit. The first plating unit, the
first-chemical mechanical polishing unit, the cleaning unit, the
drying unit, and the substrate transfer unit are combined into a
unitary arrangement. In other words, similar to the previous
patents, the station of U.S. Pat. No. 6,294,059 can also be
classified as a cluster-tool station with a common robot which
serves different functional units combined into an indivisible
unity.
OBJECTS AND SUMMARY OF THE INVENTION
[0014] It is an object of the present invention to provide a
processing station that contains a plurality of individual and
independently operating processing chambers arranged in
multiple-level manner vertically and in linear rows horizontally
with transfer of objects by means of by a common workpiece handling
unit. It is another object is to provide the aforementioned station
suitable for electroless deposition in the mass production of
semiconductor wafers with high interconnect density. A further
object is to provide the aforementioned station which is universal
in use, flexible for restructuring in accordance with specific
production requirements, highly efficient in production due to
parallel operation of a plurality of chemical processing chambers
in accordance with a required sequence, and occupying a reduced
floor area due to the use of a common industrial robot for
transferring objects between the service area and the equipment of
the clean room. It is another object to provide the aforementioned
station in which a maximum possible amount of equipment units can
be transferred from the clean room to the service area thus
reducing the floor space occupied by the equipment in the
clean-room area. It is a further object to provide a chemically
processing station with spatial arrangement of interacting station
units, such as processing modules, wafer cassettes, and a
wafer-handling unit.
[0015] The present invention discloses a station, e.g., for IC
fabrication with a flexible configuration. It consists of an array
of processing chambers, which are grouped into processing modules
and arranged in a two dimensional fashion, and is capable of
operating independent of each other. Each processing chamber can
perform electroless deposition and other related processing steps
sequentially on a wafer with more than one processing fluids
without having to remove it from the chamber. The system is served
by a two-tiered fluid distribution and delivery system. Only one
robot arm is employed which can be randomly accessed and transport
wafers between the wafer cassettes and any of the processing
chambers. If necessary, the station can be arranged in a
three-dimensional pattern.
[0016] In summary, the deposition system consists of:
[0017] 1. A single-wafer processing tool.
[0018] 2. A single-robot system to handle multiple wafer cassettes
(FOUPs [Front Opening Unified Pods] or SMIF [Standard Mechanical
Interface] boxes) and multiple processing modules.
[0019] 3. Multiple (single-wafer) processing chambers in a
processing module.
[0020] 4. Each processing chamber is able to perform different
processing steps with different chemicals without the need of
moving the wafer to a different processing chamber.
[0021] 5. Each processing chamber is capable of receiving a clean
wafer from the wafer cassette and then return a clean wafer back to
a wafer cassette, after all the required processing steps are
completed.
[0022] 6. Each processing chamber is isolated from the Front end
(and therefore from the clean room) with a specially designed gate
valve suitable for receiving and discharging semiconductor
wafers.
[0023] 7. Each processing module contains a Fluid Distribution Unit
that supplies processing chemicals to the multiple processing
chambers in the module.
[0024] 8. Each processing module contains a power electronics unit
and controls/communications electronics unit servicing multiple
processing chambers within one processing module.
[0025] 9. A remote Chemical Distribution Module that supplies
processing chemicals to multiples of Fluid Distribution Units (or
processing modules).
[0026] 10. The new system configuration results in the smallest
possible equipment size for a relatively slow process than any
other electroless deposition tool; this design will also result in
lower cost and higher system reliability.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a three-dimensional general view of a
spatially-arranged single-wafer chemical processing station of the
invention.
[0028] FIG. 2 is a more detailed view of the piping arrangements
for the supply of liquids to and from the process chambers of the
station.
[0029] FIG. 3 is a top view on a chemical processing station of the
invention having a three-dimensional arrangement of the station
units.
DETAILED DESCRIPTION OF THE INVENTION
[0030] This invention discloses the equipment configuration which
is both novel and flexible, for the electroless deposition of
copper, passivation layer, and a barrier layer. The apparatus
consists of a number of processing modules and each module in turn
a number of process chambers. At least one of the chambers is
capable of depositing thin metal films by electroless means. All
necessary processing steps for film deposition are performed in a
single processing chamber. Thus, the unit provides a way of
reducing the number of times the wafer needs to be transferred
between wet steps.
[0031] Reference is made to FIG. 1, which is a three-dimensional
general view of a single-wafer electroless deposition station
(hereinafter referred to as "system") of this invention. The system
is designated as a whole by the reference numeral 100. The system
consists of a multiple number of processing modules 10a, 10b, 10c .
. . arranged in a line in a horizontal manner (only three of them
are shown), and divided among them a multiple number of processing
chambers 70a, 70b, 70c . . . , which are arranged in a vertical
manner by way of an example, although the manner of their
arrangements is immaterial. The system also contains a number of
wafer cassettes or FOUPs 60a, 60b, 60c . . . , which are arranged
horizontally in line parallel to the processing modules 10a, 10b,
10c . . .
[0032] A wafer handling unit 50, which is installed on a carriage
52, is guided along guide rails 54 in space between the FOUPs 60a,
60b, 60c . . . and the processing modules 10a, 10b, 10c . . . . The
wafer handling unit has a rotatable mechanical arm 40 which can be
rotated in a horizontal plane and moved in a vertical direction
shown by arrow A from a drive unit 56 for transfer of the wafers
between the FOUPs 60a, 60b, 60c . . . and the processing modules
10a, 10b, 10c . . . and for vertical alignment with respective
processing chambers 70a, 70b, 70c . . .
[0033] If necessary, the mechanical arm 40 can be rotated
360.degree.. Thus wafers can be transported from the cassettes 60a,
60b, 60c, . . . to selected processing chambers 70a, 70b, 70c for
processing, and extracted and returned to the cassettes when their
required operations are completed. It is understood that the FOUPs
60a, 60b, 60c . . . and the robot with the mechanical arm 40 are
located in an enclosed clean environment (clean room 41), while the
modules 10a, 10b, 10c, . . . , solution storage tanks, etc. are
located in a service area 45 which is separated from the clean room
41 by a wall 43 having windows 47a, 47b, 47c, . . . aligned with
specially designed gate valves 48a, 48b, 48c, . . . of respective
chemical processing chambers 70a,l 70b, 70c, . . . suitable for
loading and unloading semiconductor wafers.
[0034] Working solutions and other fluids such as cleaning,
activation, or similar liquids are supplied to the respective
processing chambers 70a, 70b, 70c . . . from a respective chemical
distribution and supply unit (hereinafter referred to as "chemical
supply unit") 80a under control of a chemical management unit 20
(FIG. 1).
[0035] The disclosed configuration of an arrayed processing
chambers 70a, 70b, 70c . . . has many advantages:
[0036] 1) Since all processing chambers 70a, 70b, 70c . . . are
equivalent, there is a great flexibility in the tradeoff between
wafer throughput and the number of processing modules needed. We
can program the optimum number of wafers that undergo identical
process sequence at the same time versus the number of different
processing sequences at any one time.
[0037] 2) The chambers 70a, 70b, 70c . . . can be randomly accessed
by vectoring the robot arm 40 to the target process chamber through
the movements of the vertical/rotary drive 56 on the guide rails
54. Thus, the access times to any processing chamber are about
equal and minimized.
[0038] 3) The machine will never have to be shut down by the
failure of one or more processing chambers 70a, 70b, 70c . . . ,
since they are all equivalent.
[0039] The machine can still be used with almost normal performance
efficiency and degrades gracefully, until it can be repaired at a
convenient time.
[0040] For each processing module 10a, 10b, 10c, . . . there are a
set dedicated local chemical supply units of the type shown by
reference numeral 80a in FIG. 1. Since all chemical supply units
are essentially identical, the following description will relate
only to the chemical supply unit 80a and units associated
therewith. More specifically, the chemical supply unit 80a is
connected by pipe lines 81a with a central chemical supply tanks in
a remote chemical management unit 20. In FIG. 1, reference numeral
81b designates a pipe holder which contains individual pipes that
connects the chemical supply unit 80a with chemical processing
chambers 70a, 70b, 70c . . . of the processing module 10a through
individual pipe branches 83a, 83b, 83c . . . which constitute a
local piping distribution system. In general, the main chemical
management unit 20 is located in the service area.
[0041] The particular features and embodiments of the fluid
distribution and delivery systems and method of their operation are
disclosed in more detail in earlier U.S. patent application Ser.
No. 10/103,015 filed by the same applicant on Mar. 22, 2002.
[0042] The piping arrangements to and from the process chambers are
shown in greater detail in FIG. 2. The chemical supply unit 80a
contains a plurality of individual fluid tanks 90a, 90b, 90c, . . .
for specific liquids used in the process. For example, the tank 90a
may contain a chemical working solution for electroless deposition,
the tank 90b may contain a wetting liquid for wetting the surface
of the wafer in the initial period of the process, the tank 90c may
contain a cleaning liquid such a deionized water, etc. The
respective liquids are supplied to the tanks 90a, 90b, 90c, . . .
from respective storage tanks (not shown) of a main chemical
management unit 20. From the chemical supply unit 80a the liquids
are supplied to the chemical processing chamber 70a in a required
sequence controlled, e.g., by a controller (as described in the
aforementioned earlier patent application) through the individual
pipe branches 83a, 83b, 83c . . . . Chemical supply unit 80a also
contains hydraulic pumps 91a, 91b, 91c, . . . for the supply of
fluids from respective tanks 90a, 90b, 90c, . . . . To respective
chemical processing chambers. For loading and unloading the fluids
into and from the tanks, they are provided with fluid inlet ports
and outlet ports (only the inlet port 93a and the outlet port 95a
of the tank 90a are shown in FIG. 2). Similarly, chemical
processing chambers have an fluid inlet opening and a fluid outlet
opening (only the inlet opening 96 and an outlet opening 97 of the
chemical processing chamber 70a are shown in FIG. 2).
[0043] Both the local storage tanks 90a, 90b, 90c, . . . and the
respective storage tanks of the main chemical management unit 20
have their individual recirculation loops (not shown) for constant
circulation of the fluids between the bottom to the top level of
the same tank, with the individual attendant pumps and filters (not
shown). The fluid content of each tank is constantly being filtered
and its composition monitored in-situ and replenished in the
chemical management unit 20. As described in detail in the
aforementioned previous U.S. patent applications, each chamber
contains a substrate holder 92 (FIG. 2), which can be rotated
around a vertical axis at various angular speeds, and an edge-grip
mechanism 94 located inside the substrate holder for rotation
therewith. Wafer rotation is used to facilitate drying, or a more
uniform deposit. The wafer W on the holder 92 may be totally
immersed in the solution, or the fluid may be sprayed through
nozzles 96 at the end of the inlets while the substrate holder
rotates. Also, for certain special processing requirements, the
chamber may be pumped to vacuum, or be pressurized to several
atmospheric pressure. All these features are beyond the scope of
the present patent application.
[0044] The system of this invention is designed in such a way that
once a wafer is placed in the sealed processing chamber 70a (or
70b, 70c, . . . ), it can undergo a series of sequential processing
steps by supplying and removing the respective liquids into and
from the chemical processing chamber until a clean wafer with a
finished film is outputted. Depending on the accessory features of
the chamber, the desired processing steps may be, but certainly not
limited by, Pd activation, deposition of a barrier layer,
deposition of Cu by electroless methods, electro-polishing,
annealing, rinsing and drying. What is important to note that the
arrangement of units according to the invention would cut down
processing time and reduce oxidation and contamination due to the
simultaneous use of a plurality process modules which contain
independently operating individual chemical processing chambers
services by a common wafer handling unit 40. Each process chamber
is capable of performing multiple processing steps to complete the
deposition process without the need of-transferring the wafer
between different processing chambers.
[0045] FIG. 3 is a top view on a chemical processing station of the
invention having a three-dimensional arrangement of the station
units. This is the most optimal way for utilization of the working
space. In this arrangement, a multi-tiered modules 110a, 110b, 110c
. . . and multi-tiered modules 112a, 112b, 112c . . . are located
in a service area and organized into two parallel rows. These rows
are separated by a clean room, which contains an industrial robot
140. Wafer cassettes or FOUPs 160a, 160b and 162a, 162b are
arranged in rows which are perpendicular to the direction of module
rows. Thus, the robot 140 is located in a confined space formed by
the chemical processing modules and wafer cassettes. In fact, such
an arrangement comprises a version of a multi-tiered cluster
tool.
[0046] Thus it has been shown that the invention provides a
chemical processing station that contains a plurality of individual
and independently operating chemical processing chambers served by
a common workpiece handling unit. The aforementioned station is
suitable for electroless deposition in the mass production of
semiconductor wafers with high interconnect density. It is
universal in use, flexible for restructuring in accordance with
specific production requirements, highly efficient in production
due to parallel operation of a plurality of chemical processing
chambers in accordance with a required sequence, and occupying a
reduced floor area due to the use of a common industrial robot for
transferring objects between the service area and the equipment of
the clean room. Transfer of some units of equipment from the clean
room to the service area makes it possible to significantly reduces
the floor space occupied by the equipment in he clean room. A
multiple-layer arrangement of the chambers provides the most
efficient use of the clean-room production area.
[0047] It is to be noted that a conventional cluster-tool
processing station commonly employed in the IC factories does not
allow separation of any functional units and relocation of these
units from beyond the reach by the industrial robot. Furthermore,
such conventional stations are always use at least two robot arms,
one for picking up wafers from the FOUP to a pedestal in the
transport chamber, and another for carrying them from the transport
chamber to the processing chambers. By eliminating one of the robot
arms, and the transport chamber which usually has a relatively
large volume, the apparatus footprint is significantly reduced, the
equipment is simplified; furthermore, since excessive wafer
transfers using second robot are eliminated, the processing time
per wafer is also reduced.
[0048] Having thus described exemplary embodiments of the present
invention, it should be noted by those skilled in the art that the
disclosures within are exemplary only and that various other
alternatives, adaptations and modifications may be made within the
scope of the present invention. For example, the system may be
configured with different number of modules, chambers in the
modules, tanks in the chambers. The wafer cassettes may be
different from FOUPs. The system of the invention is applicable not
only for electroless deposition but for other processes, such
electrodeposition, or the like. The wafer handling unit may be
represented by different industrial robots equipped with different
edge grippers. The system is applicable to handling objects other
than semiconductor wafers, e.g., for CD disk substrate, or
hard-drive disk substrates. If necessary, the entire station as a
whole can be installed in a clean room.
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