Apparatus for servicing of semiconductor manufacturing equipment

A mobile container cart includes a pivoting mechanism for pivoting the container from a horizontal position to approximately 85-90 degree vertical position. The container rests atop the cart and has removable side and top plates. A semiconductor processing equipment assembly is loaded into the container while still hot. The container is sealed and pivoted to its vertical position for transport. Once at a servicing area, the container is repositioned horizontally and the top and side plates are removed. The cart now functions as a work bench for disassembling, servicing and reassembling the device. Diagnostics can be performed while the device is in the service area.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to the field of semiconductor manufacturing 
equipment and, more particularly, to a container cart for use in a 
cleanroom environment. 
2. Prior Art 
In the manufacture of VLSI and ULSI semiconductor integrated circuit 
devices, it is essential that the cleanroom environment in which these 
devices are fabricated be kept as clean as possible. This is especially 
important in the instance where these semiconductor "chips" have device or 
interconnecting line dimensions of less than one micron. Since these 
submicron dimensioned devices are fabricated in a cleanroom environment on 
the order of Class 1 or better, it is imperative that any contamination 
causing activity be either removed or isolated from the immediate 
processing area. A cleanroom is rated Class 1 if it contains no more than 
one 0.5 micron or larger particle per one cubic foot of space. 
One technique being employed in today's "cleanrooms" is to physically 
isolate the maintenance operation from the chip fabrication operation. In 
order to achieve this, today's cleanrooms incorporate maintenance 
corridors which are physically separated from the portion of the cleanroom 
where the chip fabrication occurs. The various chip processing equipment 
is then positioned so that the front of the equipment, which is utilized 
for chip manufacturing, faces the fabrication environment, while the back 
of the equipment resides in or faces the maintenance corridor. When this 
particular equipment requires servicing, maintenance personnel will access 
and service the equipment from the maintenance corridor so that any 
contaminants introduced or dislodged by this servicing activity will be 
retained in the maintenance corridor and will not be introduced into the 
chip manufacturing side of the cleanroom. 
However, although this is a sound technique for reducing the possibility of 
contaminating the cleanroom environment, there are instances when this 
approach is not workable. In some instances, a particular servicing task 
for the equipment requires entry to or within the chip fabrication 
environment. For example, when the front panel of the equipment needs to 
be removed for service access or, when the equipment resides completely 
within the fabrication environment, maintenance activities will be forced 
to coexist with chip fabrication. 
In other instances, either preventative or corrective maintenance will 
require certain assemblies of a particular piece of equipment to be 
dismantled. The equipment being dismantled, can potentially introduce 
contaminants into the cleanroom. For example, in a particular piece of 
equipment used to deposit tungsten onto a semiconductor wafer, the wafer 
is subjected to very high temperatures in the range of 
400.degree.-490.degree. C. The tungsten tends to deposit on the tooling 
and the chamber of the reactor. After prolonged use, this deposited 
tungsten residue needs to be removed from the reactor components. Because 
the equipment itself cannot be removed from the cleanroom environment 
without causing a major disruption of the fab operation, maintenance 
personnel typically dismantle the reactor components in the cleanroom in 
order to service the system. However, the reactor must necessarily be 
cooled down before maintenance personnel can physically dismantle the 
reactor assembly. One unfortunate result of permitting the equipment to be 
cooled to room temperature prior to performing the maintenance is that the 
residual tungsten deposited within the chamber tends to flake off. This 
results in the introduction of significant quantities of tungsten 
contaminants into the cleanroom environment. 
Additionally, further contaminants are introduced into the cleanroom 
environment from the actions of the maintenance personnel in servicing the 
equipment. For example, tools and equipment which are typically stored 
outside of the cleanroom must necessarily be brought into the cleanroom, 
for not only the removal and repair of the assembly, but for required 
diagnostic functions after the assembly has been cleaned and replaced back 
in the equipment. 
Thus, it is necessary that in such instances where the maintenance activity 
must occur in the cleanroom, additional care must be exercised to reduce 
or prevent contamination from occurring as a result of such activity. It 
is preferable to remove any portion of such activity from the cleanroom, 
if possible, in order to reduce the risk of cleanroom contamination. The 
present invention provides for an apparatus for permitting the bulk of the 
maintenance activity to be performed outside of the fabrication and/or the 
maintenance portion of the cleanroom. 
SUMMARY OF THE INVENTION 
A container cart for use in a cleanroom environment is described. The cart 
is comprised of a mobile support assembly which provides a container for 
housing an equipment assembly which is used for the processing of 
semiconductor wafers. 
The support assembly includes a base frame member with horizontal support 
bars. Vertically extending stanchions support a pillow block and rod 
assembly which is affixed to the underside of a bottom plate for 
supporting the container housing assembly. A handle is provided at one end 
of the cart for manipulating and transporting the cart. 
The housing assembly is comprised of a number of side plates. Each side 
plate is clamped to other adjacent side plates, as well as to the bottom 
plate. The total number of side plates will depend on the design for the 
particular equipment or assembly being serviced. A top cover plate is 
clamped onto the side plates to seal the container. The top and side 
plates are of double-wall design with openings cut out of the outer wall 
panel of each plate for heat dissipation and safety. 
A pivoting mechanism comprised of a jack and a pivot bracket reside between 
vertical stanchions. One end of the jack is coupled to the base frame 
while its other end is coupled to the underside of the bottom plate at a 
point off center from a central axis of the container. The pillow block 
and rod assembly coupled to the stanchions are located such that the rod 
is along the central axis of the container. When the jack is extended, the 
container is in the horizontal position. However, when the jack is 
retracted by a hand crank coupled to the jack, the bottom plate of the 
container pivots along its central axis causing the container to rotate 
approximately 85-90 degrees into an almost vertical position. The 
container now resides within the width of the base frame of the cart, 
permitting the complete unit to be transported through a standard width 
doorway. 
In operation, the particular equipment or assembly is loaded into the 
horizontally positioned base plate and secured. Side plates are assembled 
to form a container. The top cover plate is positioned onto the side 
plates to seal the container. The loading operation can be performed while 
the device is still hot in order to prevent contaminants flaking off when 
the device cools. The jack is used to rotate the container to its vertical 
position for transport to a servicing area. 
Once at the servicing area, the container is again brought to its 
horizontal position. The top and side plates are removed completely such 
that the cart and the bottom plate function as a work bench. The device 
can then be dismantled, serviced and reassembled. Once reassembled, 
various diagnostic tests can be performed on the device while it is still 
in the service area.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The present invention describes an apparatus for use in servicing a 
semiconductor processing equipment assembly in a cleanroom environment. In 
the following description numerous specific details are set forth, such as 
specific type of reactor, structure, shape, etc., in order to provide a 
thorough understanding of the present invention. It will be obvious, 
however, to one skilled in the art, that the present invention may be 
practiced without these specific details. In other instances, well-known 
methods and structures have not been set forth, in order not to 
unnecessarily obscure the present invention. 
Referring to FIG. 1, a reactor assembly 10 utilized for semiconductor 
processing is shown. Reactor 10 is commonly referred to as a turret 
assembly and includes a number of chucks 12 configured around a hub 
assembly 11. The particular turret assembly 10 illustrated in FIG. 1 is a 
six chuck reactor assembly, wherein the chucks 12 are configured in a 
hexagonal arrangement around the hexagonal shaped hub 11. The particular 
turret assembly 10 illustrated in FIG. 1 is manufactured by Genus 
Corporation of Mountain View, Calif. and sold under Model Number 
8720/8710. 
An assembled turret is installed into the process chamber of the Genus 
8720/8710 system. Various gases are then fed into the process chamber and 
react to deposit a tungsten film. When placed in the equipment, each of 
the chucks 12 is coupled to receive a circular semiconductor wafer. The 
wafer resides behind the clamp ring 14 at the extreme outer periphery of 
each chuck of assembly 10. In this particular equipment, up to six 
semiconductor wafers can be processed, one by each chuck 12, for the 
deposition of tungsten. 
Although a particular assembly 10 is shown in FIG. 1, it is shown for 
illustrative purpose only. It is to be appreciated that the present 
invention can be configured to function with a variety of semiconductor 
fabrication assemblies and equipment which are utilized in various 
processing functions. 
Referring to FIGS. 2-7, an apparatus 20 of the present invention is shown. 
Apparatus 20, for purposes of simplicity is commonly referred to as a 
"cart". Further, because for this particular purpose, cart 20 has been 
designed to function in conjunction with the servicing of the above 
described turret assembly 10, apparatus 20 for exemplary purpose only, is 
commonly referred to as a "turret cart". The two main assemblies of cart 
20 are a mobile support assembly 21 and an enclosed housing assembly 22. 
The enclosed housing assembly 22 can be disassembled. 
Support assembly 21 is comprised of a base frame 25, vertical frame 26, 
handle 27, vertical support member 24 and pivoting mechanism 28. The base 
frame 25 is rectangular in shape having three parallel support bars 31a-c 
located interior of the rectangular shape of the frame and extending 
across the two opposing sides of the rectangular shape, such that the 
complete frame 25 is planar to the floor. Four wheels 29 are placed on the 
underside of frame 25 in order to provide for the mobility of cart 20. 
Wheels 29 of the preferred embodiment are plastic caster, pivoting wheels 
which can be locked to prevent any rolling movement. 
The vertical frame 26 is comprised of two stanchions 32 which rise 
perpendicularly upward from the middle support bar 31b. A support bar 33 
is coupled between each stanchion 32 to the outer edge of base frame 25 to 
provide an "A-frame" type support to retain stanchions 32 in the upright 
(vertical) position. A rod 35 extends across the upper end of the 
stanchions 32 and the ends of the rod 35 are anchored to the stanchions. 
The rod 35 passes through the central opening of two pillow blocks 36 
which are used for supporting the housing assembly 22. Pillow blocks 36 
each include bearings in order to permit rod 35 to rotate therein. 
Positioned between the vertical frame members 26 is the pivoting mechanism 
28. Pivoting mechanism 28 includes a worm gear driven jack 37, pivot 
bracket 38 and a hand crank 39. The crank 39 is coupled to jack 37 by the 
use of a double "U-joint" connecting rod 44. The mechanically operated 
jack 37 is positioned at one end coupled to a jack base 43, which is 
affixed to support bar 31a. An "A-frame" support bar 34 extends across 
support bars 31a and 31b to further support jack 37 at its lower end. The 
"A-frame" support bar 34 is pinned to the lower end of jack 37 to permit 
the lower end of jack 37 to swivel slightly during operation of the jack. 
The upper end of jack 37 is coupled to the housing assembly 22 by pivot 
bracket 38. A pin is used to couple the upper end of jack 37 to the pivot 
bracket 38 for rotation of housing assembly 22. 
Handle 27 is comprised of two vertical bars 45 extending upward vertically 
from one edge of frame 25 adjacent to one end of bars 31. Bars 45, 
approximately midway up, then angle outward from the support assembly 21 
and are terminated at the extremity by a horizontal bar 46, which is 
coupled across the two vertical bars 45. 
The housing assembly 22 is comprised of a bottom plate 40, top plate 41, 
and a plurality of side plates 42, which are shown in more detail in FIGS. 
8-11. In this particular example, because turret 10 is hexagonal, six side 
plates 42 are used to provide a hexagonal shaped housing to accommodate 
the hexagonal shaped turret 10. Furthermore, top plate 41 is actually 
comprised of two half-sections. Clamps 51 are utilized to clamp each side 
plate 42 onto the bottom plate 40. Clamps 53 are used to clamp each of the 
side plates to its adjacent side plates. Clamps 52 are also utilized to 
clamp the top plate 41 onto the side plates 42. Clamps 51-53 can be of a 
variety of well-known prior art devices utilized for the purpose of 
clamping the plates. 
In this particular embodiment, each side plate includes two clamps 51 for 
clamping the side plate 42 onto the bottom plate 40. Only one clamp 53, 
located at the upper right corner of each plate 42, is used to couple that 
particular side plate 42 to its right adjacent plate. For each side plate 
42, one clamp is used to couple it to the top plate 41. However, it is to 
be understood that the actual number of clamps which can be utilized is a 
mere design choice, as long as a fully enclosed container can be assembled 
by the coupling of the various plates 40-42. Furthermore, the side edges 
of the side plates 42 are beveled in order for the adjacent side plates 42 
to join to form the hexagonal shape. An exemplary illustration for 
utilizing a clamp for clamping is shown in FIG. 9. 
The top plate 41 and the side plates 42 are double walled, having a thicker 
outer panel and a thinner inner panel to form the double-wall. The panels 
are separated by screw spacers 55. A circular opening 56 is cut in the 
outer plate of each of the side plates 42. Two openings 57 are cut in the 
outer panel of the top plate 41, one opening 57 in each half of the plate 
41. The purpose of the inner panel and the openings 56-57 in the outer 
panel are for heat dissipation. The double-wall design is utilized so that 
the outer panel remains cooler than the inner panel for purposes of safety 
to the operator. 
The bottom plate 40 is affixed to the support assembly 22 by pillow blocks 
36 and pivot bracket 38. Blocks 36 are affixed to the bottom plate 40 
along a central axis 60 of bottom plate 40. Pivot bracket 38 is affixed 
off center from the central axis 60 so that the upper end of jack 37, when 
extended, provides the support to maintain the bottom plate 40 parallel to 
the floor. When the bottom plate is in this horizontal position, it also 
rests on the vertical support member 24. Support member 24 is located to 
provide support to the housing assembly 22 on the opposite side of the 
central axis 60 as the pivot bracket 38. A mounting block 49 and standoff 
plate 50 are provided on the interior of the bottom plate 40 for mounting 
the particular assembly which is to be serviced. 
In operation, the turret cart 20, including the housing assembly 22 is 
wheeled adjacent to the particular equipment which is to be serviced. The 
housing assembly 22 is placed in the horizontal position with the jack 37 
extended. The top plate 41 is removed. The side plates 42 are clamped in 
the assembled position. Once the particular subassembly has been detached 
or dismantled from its equipment, it is loaded into the housing assembly 
22. In the particular example, a lifting spider 15 is screwed onto the hub 
11 of turret 10. An "eye" bolt 13 on the lifting spider 15 provides for a 
place of attachment for removal of the turret 10. A hoist is used to lift 
the turret 10 out of its equipment by coupling the hoist cable to the eye 
bolt 13. 
Although the removal of the turret 10 can be accomplished after it has 
cooled, the preferred method is to remove the turret 10 while it is still 
hot. An advantage of removing the turret 10 while it is hot is that less 
tungsten residue will flake off of the turret 10. It also saves time in 
performing the necessary maintenance, thereby reducing the "down time" of 
the equipment. 
Once the turret 10 has been loaded into the housing assembly 22, it is 
secured to the bottom plate 40 by bolts 16. Holes are provided in the hub 
11 of the turret 10, which are utilized for securing the turret 10 to its 
equipment. These same holes are now utilized to hold bolts 16 for securing 
the turret 10 to the bottom plate 40. It is to be noted that the turret 10 
can be mounted first onto the bottom plate 40 prior to assembling the side 
plates 42. 
Once the turret 10 is secured in housing assembly 22 with side plates 42 
also assembled, the two halves of top plate 41 are placed onto the housing 
assembly 22 and secured to the side plates 42 by clamps 52. When the 
turret 10 is of sufficiently hot temperature, care must be observed in 
removing, placing and securing the turret 10 into the housing assembly 22. 
The double walls of the top and side plates 41 and 42 provide for heat 
dissipation from the interior of the housing assembly 22 while containing 
most of the particulates. The double-wall scheme along with the openings 
56-57 allow for heat to be dissipated from the interior of the housing 
assembly 22 to the surrounding ambient environment, yet leaving the outer 
panel safer to touch. 
The turret 10 is then transported to a desirable location for providing the 
necessary service. Typically, this maintenance facility is separate or 
isolated from the portion of the fab utilized for semiconductor 
fabrication. During transport, if cart 20 must necessarily pass through a 
doorway, it is possible that the width of the doorway may not permit the 
passage of the cart. For example, with the particular turret 10, the width 
of the housing assembly 22 in the horizontal position is larger than the 
width of a standard doorway. However, the pivoting mechanism 28 of the 
present invention permits the housing assembly 22 to be rotated, such that 
the cart 20 and the turret 10 can pass readily through such a doorway. 
The hand crank 39 is utilized to manually retract the piston of the jack 
37. As the jack 37 is retracted, that portion of the housing assembly 22 
coupled to jack 37 is caused to pivot downward due to the rotation of rod 
35. When fully retracted, the housing assembly 22 has been rotated 
approximately 85 to 90 degrees and a lower portion of the bottom plate 40 
rests proximately along stanchion 32. In such a rotated position, the 
width of the housing unit is now determined substantially by the height of 
the side plates 42 wherein such dimension is less than that of the width 
of the support assembly 21. Thus, cart 20 is now no wider then the width 
of the support assembly 21. Once the cart assembly 20 is transported to 
the desired location, the jack 37 is manipulated in the opposite direction 
to extend the piston, such that the housing assembly 22 is again in its 
horizontal position. It is to be appreciated that the actual amount of 
angular rotation of housing assembly 22 is a design choice. 
In order to perform the service work on the turret 10, the top plate 41 and 
the side plates 42 are unclamped and removed. In actual practice, the 
preferred embodiment uses a two-piece double-walled top plate for top 
plate 41. This top plate 41 is comprised of two half-sections which mate 
along axis 60 to enclose the housing assembly 22. The two half sections of 
the top plate 41 are stored under the support assembly 21 by inserting it 
onto dual rails 63 located under the support assembly 21. Likewise, the 
side plates 42 are disassembled and stored in the slots 65 provided within 
box 64, which is attached to the support assembly 21. Box 64 is affixed to 
frame 25 at the opposite end from handle 27. A partially assembled or 
dismantled unit is shown in FIG. 2. 
Once the top and side plates 41 and 42 have been disassembled, the turret 
10 can be serviced. It is preferred that the assembly has cooled to room 
temperature or thereabouts in order not to present a temperature hazard to 
the maintenance personnel. Although the turret 10 can be removed from the 
bottom plate 40 for servicing, cart 20 has been designed to alleviate the 
need for such removal. The actual disassembly of the turret 10 can be 
achieved while the hub 11 is still mounted on the bottom plate 40. The 
cart 20 and the bottom plate 40 essentially operate as a work bench for 
servicing turret 20. After completion of the required service, turret 10 
is reassembled on the cart. It can then be tested in order to determine if 
the turret 10 is ready for reinstallation into the equipment. 
It is to be noted that in the prior art, the various diagnostic functions 
were necessarily performed at the location of the equipment since the 
turret 10 was disassembled and reassembled in the equipment. By utilizing 
the present invention, the various diagnostics, such as helium leak 
testing, can now be performed at a remote location from the equipment, 
thereby reducing the amount of contaminants which could be introduced into 
the cleanroom environment from such testing and the associated instruments 
and/or tools. 
Although a variety of structurally sound materials can be used to construct 
cart 20, the preferred embodiment uses stainless steel for most 
components. Bottom plate 40 and assembly standoff plate 50 are fabricated 
from aluminum. The external panel of side plates 42 are aluminum while the 
inner panels are stainless steel. Both panels of the top plate 41 are made 
from stainless steel. Aluminum is utilized not to unnecessarily add weight 
to the device. The support assembly 21 is fabricated from stainless steel. 
The wheels 29 are polypropolene plastic and the box 64 is constructed from 
a sheet of polypropolene. 
The dimensions of the various components will depend on the particular 
assembly to be serviced and, thus, is a design choice. However, it is 
preferred that the width of the cart be such that it can readily fit 
though a standard width doorway. The weight and size of any equipment or 
assembly used with the container cart will determine the actual dimensions 
and materials used to construct the container cart of the present 
invention. Instability and balance are of prime concern when the housing 
assembly is rotated into the vertical position. Furthermore, the material 
will also depend on the temperatures encountered. The apparatus of the 
present invention is capable of containing assemblies which are at 
temperatures in the range of 400.degree.-490.degree. C. 
Thus, a container cart for servicing semiconductor equipment and assemblies 
is described.