Chemistry: electrical and wave energy – Apparatus – Electrolytic
Reexamination Certificate
2001-03-01
2004-01-06
Nguyen, Nam (Department: 1753)
Chemistry: electrical and wave energy
Apparatus
Electrolytic
C204S275100, C204S277000, C204S278000, C204S297010
Reexamination Certificate
active
06673216
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to methods and apparatuses for providing electrical and fluid communication to rotating microelectronic workpieces during electrochemical processing.
BACKGROUND
Semiconductor integrated circuits and other microelectronic devices typically include a substrate or workpiece, such as a silicon wafer, and one or more metal layers disposed on the workpiece. The metal layers are typically used to interconnect components of the integrated circuit. Metal layers may also define devices such as read/write heads, micro electrical-mechanical devices, and other microelectronic structures. The metal layers can be formed from metals such as nickel, tungsten, solder, platinum, and copper. The metal layers can be formed on the workpiece with techniques such as chemical vapor deposition (CVD), physical vapor deposition (PVD), electroplating, and electroless plating.
In one electrochemical plating process, a very thin seed layer of metal is applied to the workpiece using physical or chemical vapor deposition and is deposited to a thickness of approximately 1,000 angstroms. An electrical current is applied to the seed layer while the workpiece is immersed in an electrochemical processing fluid to form a thicker blanket layer on the seed layer. The blanket layer can have a thickness of approximately 6,000 to 15,000 angstroms and can fill trenches, vias and other apertures in the workpiece to provide electrically conductive features within the apertures. After the blanket layer has been electroplated onto the workpiece, excess metal material can be removed (for example, using chemical-mechanical planarization) and subsequent structures can then be disposed on the resulting metal layer.
FIG. 1
is a cross-sectional side elevational view of a conventional apparatus
10
for electroplating a microelectronic workpiece
23
. The apparatus
10
includes a cup
12
supplied with electrochemical processing fluid via a supply tube
16
. The supply tube
16
also supports a positively charged anode
13
. The cup
12
includes sidewalls
17
having an upper edge
18
that defines a free surface
19
of the processing fluid. The processing fluid flows through the supply tube
16
, into the cup
12
and over the sidewalls
17
into an overflow vessel
11
, as indicated by arrows “S.” The fluid can be removed from the bottom of the overflow vessel
11
for disposal or recirculation.
A reactor head
20
supports the microelectronic workpiece
23
relative to the processing fluid in the cup
12
and is movable relative to the cup
12
and the overflow vessel
11
between a closed position (shown in
FIG. 1
) with the workpiece
23
in contact with the processing fluid, and an open position. The reactor head
20
includes a workpiece support or rotor
21
that supports the microelectronic workpiece
23
in a facedown orientation. The support
21
includes a contact assembly
22
having a plurality of electrical contact points
27
that can be removably coupled to a conductive surface (such as a seed layer) of the microelectronic workpiece
23
. A backing plate
4
biases the workpiece
23
into engagement with the contact points
27
and is moveable relative to the workpiece
23
between an engaged position (shown in solid lines in
FIG. 1
) and a disengaged position (shown in broken lines in FIG.
1
). A bellows seal
3
surrounds the backing plate
4
. The support
21
is rotatably coupled to the reactor head
20
with a shaft
30
connected to a motor
24
. Accordingly, the support
21
and the workpiece
23
can rotate relative to the reactor head
20
and the cup
12
(as indicated by arrows “R”) while a negative electrical charge is applied to the electrical contact points
27
to attract conductive ions in the processing fluid to the conductive surface of the workpiece
23
.
In one aspect of the conventional arrangement shown in
FIG. 1
, electrical power is transmitted from the non-rotating reactor head
20
to the rotating microelectronic workpiece
23
via a rotating electrical connection. For example, as shown in
FIG. 2
, the shaft
30
can include a conductor
31
connected at a lower end to the contact assembly
22
(
FIG. 1
) and connected at an upper end to a rotary contact
60
that rotates with the shaft
30
. The reactor head
20
(
FIG. 1
) can support a fixed contact
70
that is connected with a cable
34
to a power source (not shown). Accordingly, the shaft
30
and the rotary contact
60
rotate relative to the fixed contact
70
while maintaining electrical contact with the fixed contact
70
and the microelectronic workpiece
23
.
In another conventional arrangement, it may be advantageous to purge oxygen from a region proximate to the junction between the microelectronic workpiece
23
(
FIG. 1
) and the contact assembly
22
, for example, to minimize etching of the seed layer and/or reduce the likelihood for oxidizing the seed layer. Accordingly, the apparatus
10
(
FIG. 1
) can include a purge fluid pathway that provides purge fluid to the support
21
via the shaft
30
. In one aspect of this arrangement (shown in FIG.
3
), the shaft
30
can include a fluid channel
41
having an entrance port
45
at one end and an exit port
44
at the opposite end. The entrance port
45
extends through the rotary contact
60
and aligns with an axial supply passage
71
extending through the fixed contact
70
. The fixed contact
70
also includes a fluid connector
72
for coupling to a source of purge fluid (not shown). Accordingly, the purge fluid can be supplied to the fluid connector
72
, through the fixed contact
70
, through the rotary contact
60
, and through the shaft
30
to the junction region between the microelectronic workpiece
23
and the contact assembly
22
.
SUMMARY
The invention is directed to apparatuses and methods for transmitting electrical signals and fluids to and/or from a microelectronic workpiece. In one aspect of the invention, the apparatus can include a shaft rotatable about a shaft axis. The shaft can have a first end with a first electrical contact portion toward the first end, a second end opposite the first end, and an internal channel along the shaft axis between the first and second ends. The shaft can further have at least one first hole toward the first end extending radially from the channel to an external surface of the shaft. At least one second hole extends through the shaft from the channel to the external surface of the shaft toward the second end of the shaft. A housing rotatably receives the shaft, and the housing has an aperture coupleable to a fluid source and/or a fluid sink. The housing has a fluid passage positioned adjacent to at least one first hole of the shaft, with the fluid passage in fluid communication with the aperture when the shaft rotates relative to the housing. The housing has a second electrical contact portion engaged with the first electrical contact portion to transmit electrical signals between the first and second electrical contact portions when the shaft rotates relative to the housing.
In a further aspect of the invention, the apparatus can include an inner race fixed relative to the shaft to rotate with the shaft, and an outer race fixed relative to the housing. A first ball-bearing assembly is positioned between the inner race and the housing, and a second ball-bearing assembly is positioned between the inner race and the housing at an axial distance from the first ball-bearing assembly. A first seal is fixed relative to the outer race and is engaged with the inner race proximate to the first ball-bearing assembly, and a second seal is fixed relative to the outer race and engaged with the outer race proximate to the second ball bearing assembly. The inner race, the outer race, and the first and second seals define the fluid passage of the housing.
In still a further aspect of the invention, the housing and the shaft can be included in an apparatus for electrochemically processing a microelectronic workpiece. The apparatus can further include a reactor vessel,
Erickson James J.
Pedersen John M.
Mutschler Brian L
Nguyen Nam
Semitool Inc.
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