Abrading – Flexible-member tool – per se – Interrupted or composite work face
Reexamination Certificate
2002-05-10
2004-07-06
McDonald, Shantese (Department: 3723)
Abrading
Flexible-member tool, per se
Interrupted or composite work face
C451S041000
Reexamination Certificate
active
06758735
ABSTRACT:
TECHNICAL FIELD
This invention relates to planarizing pads in mechanical and/or chemical-mechanical planarization of microelectronic substrates.
BACKGROUND
Mechanical and chemical-mechanical planarization processes (collectively “CMP”) are used in the manufacturing of electronic devices for forming a flat surface on semiconductor wafers, field emission displays and many other microelectronic device substrate assemblies. CMP processes generally remove material from a substrate assembly to create a highly planar surface at a precise elevation in the layers of material on the substrate assembly.
FIG. 1
schematically illustrates an existing web-format planarizing machine
10
for planarizing a substrate
12
. The planarizing machine
10
has a support table
14
with a top-panel
16
at a workstation where an operative portion (A) of a planarizing pad
40
is positioned. The top-panel
16
is generally a rigid plate to provide a flat, solid surface to which a particular section of the planarizing pad
40
may be secured during planarization.
The planarizing machine
10
also has a plurality of rollers to guide, position and hold the planarizing pad
40
over the top-panel
16
. The rollers include a supply roller
20
, idler rollers
21
, guide rollers
22
, and a take-up roller
23
. The supply roller
20
carries an unused or pre-operative portion of the planarizing pad
40
, and the take-up roller
23
carries a used or post-operative portion of the planarizing pad
40
. Additionally, the left idler roller
21
and the upper guide roller
22
stretch the planarizing pad
40
over the top-panel
16
to hold the planarizing pad
40
stationary during operation. A motor (not shown) generally drives the take-up roller
23
to sequentially advance the planarizing pad
40
across the top-panel
16
, and the motor can also drive the supply roller
20
. Accordingly, clean pre-operative sections of the planarizing pad
40
may be quickly substituted for used sections to provide a consistent surface for planarizing and/or cleaning the substrate
12
.
The web-format planarizing machine
10
also has a carrier assembly
30
that controls and protects the substrate
12
during planarization. The carrier assembly
30
generally has a substrate holder
32
to pick up, hold and release the substrate
12
at appropriate stages of the planarizing process. Several nozzles
33
attached to the substrate holder
32
dispense a planarizing solution
44
onto a planarizing surface
42
of the planarizing pad
40
. The carrier assembly
30
also generally has a support gantry
34
carrying a drive assembly
35
that can translate along the gantry
34
. The drive assembly
35
generally has an actuator
36
, a drive shaft
37
coupled to the actuator
36
, and an arm
38
projecting from the drive shaft
37
. The arm
38
carries the substrate holder
32
via a terminal shaft
39
such that the drive assembly
35
orbits the substrate holder
32
about an axis B—B (as indicated by arrow R
1
). The terminal shaft
39
may also rotate the substrate holder
32
about its central axis C—C (as indicated by arrow R
2
).
The planarizing pad
40
and the planarizing solution
44
define a planarizing medium that mechanically and/or chemically-mechanically removes material from the surface of the substrate
12
. The planarizing pad
40
used in the web-format planarizing machine
10
is typically a fixed-abrasive planarizing pad in which abrasive particles are fixedly bonded to a suspension material. In fixed-abrasive applications, the planarizing solution is a “clean solution” without abrasive particles because the abrasive particles are fixedly distributed across the planarizing surface
42
of the planarizing pad
40
. In other applications, the planarizing pad
40
may be a non-abrasive pad without abrasive particles that is composed of a polymeric material (e.g., polyurethane) or other suitable materials. The planarizing solutions
44
used with the non-abrasive planarizing pads are typically CMP slurries with abrasive particles and chemicals to remove material from a substrate.
To planarize the substrate
12
with the planarizing machine
10
, the carrier assembly
30
presses the substrate
12
against the planarizing surface
42
of the planarizing pad
40
in the presence of the planarizing solution
44
. The drive assembly
35
then orbits the substrate holder
32
about the axis B—B, and optionally rotates the substrate holder
32
about the axis C—C, to translate the substrate
12
across the planarizing surface
42
. As a result, the abrasive particles and/or the chemicals in the planarizing medium remove material from the surface of the substrate
12
.
The CMP processes should consistently and accurately produce a uniformly planar surface on the substrate assembly to enable precise fabrication of circuits and photo-patterns. During the fabrication of transistors, contacts, interconnects and other features, many substrate assemblies develop large “step heights” that create a highly topographic surface across the substrate assembly. Such highly topographical surfaces can impair the accuracy of subsequent photolithographic procedures and other processes that are necessary for forming sub-micron features. For example, it is difficult to accurately focus photo patterns to within tolerances approaching 0.1 micron on topographic substrate surfaces because sub-micron photolithographic equipment generally has a very limited depth of field. Thus, CMP processes are often used to transform a topographical substrate surface into a highly uniform, planar substrate surface at various stages of manufacturing the microelectronic devices.
One problem with conventional CMP methods is that the planarizing surface
42
of the planarizing pad
40
can wear unevenly or become glazed with accumulations of slurry and/or material removed from the substrate
12
or the planarizing pad
40
. One conventional approach to address this problem is to condition the planarizing pad
40
by abrading the planarizing surface
42
with an abrasive disk (not shown). In a typical conditioning cycle, the abrasive disk removes accumulations of waste matter and also removes a layer of material from the pad
40
. A drawback with this approach is that the equipment required for conditioning the planarizing pad
40
adds complexity to the planarizing machine
10
. Moreover, if the conditioning operation is performed separately from the planarizing operation, it reduces the time that the planarizing pad
40
is available for planarizing substrates. Conventional conditioning processes can thus limit the overall efficiency and throughput of the apparatus.
An additional drawback of methods that condition pads with a conditioning stone is that it is difficult to condition pads with grooves or small voids without destroying the grooves. Conditioning stones, for example, may produce inconsistent distributions of grooves on the planarizing surface of a planarizing pad from one planarizing cycle to another. Conditioning stones may also change the depth or the width of existing grooves over the life of a planarizing pad. Conditioning planarizing pads with conditioning stones may thus produce a non-uniform or inconsistent distribution of slurry under a microelectronic device substrate assembly. Therefore, conditioning stones often cause planarizing pads to produce inconsistent polishing rates over the life of the pads.
One approach to address this drawback is to eliminate the need to condition the pad by making the planarizing surface or the entire planarizing pad disposable. For example, U.S. application Ser. No. 09/001,333, which is herein incorporated by reference, discloses a disposable planarizing pad film made from materials such as Mylar or polycarbonate. The pads disclosed in application Ser. No. 09/001,333 can have microfeatures of different heights that entrap small volumes of an abrasive slurry and maintain the slurry in contact with the substrate. The microfeatures can be formed using a variety of techniques, such as embossing or photo-pa
McDonald Shantese
Micro)n Technology, Inc.
Perkins Coie LLP
LandOfFree
Methods and apparatuses for making and using planarizing... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Methods and apparatuses for making and using planarizing..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Methods and apparatuses for making and using planarizing... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3196034