U.S. patent application number 11/615089 was filed with the patent office on 2007-06-28 for monitoring device of chemical mechanical polishing apparatus.
Invention is credited to Jae Young Choi.
Application Number | 20070149094 11/615089 |
Document ID | / |
Family ID | 38194486 |
Filed Date | 2007-06-28 |
United States Patent
Application |
20070149094 |
Kind Code |
A1 |
Choi; Jae Young |
June 28, 2007 |
Monitoring Device of Chemical Mechanical Polishing Apparatus
Abstract
A monitoring device and method of a chemical mechanical
polishing apparatus are provided. Embodiments may form a uniform
surface of a polishing pad and monitor a CMP process by
incorporating piezoelectric sensors capable of monitoring a
pressure applied to a pad on a rear surface of a polishing pad. The
monitoring device can include: a polishing pad; a plurality of
piezoelectric sensors formed at a rear surface of the polishing pad
for detecting a pressure applied to the polishing pad; a
communication section connected to the piezoelectric sensors for
transmitting data detected by the piezoelectric sensors; and a
display section for displaying the data transmitted from the
communication section.
Inventors: |
Choi; Jae Young; (Dong-gu,
KR) |
Correspondence
Address: |
SALIWANCHIK LLOYD & SALIWANCHIK;A PROFESSIONAL ASSOCIATION
PO BOX 142950
GAINESVILLE
FL
32614-2950
US
|
Family ID: |
38194486 |
Appl. No.: |
11/615089 |
Filed: |
December 22, 2006 |
Current U.S.
Class: |
451/8 |
Current CPC
Class: |
B24B 49/10 20130101;
G05B 2219/37357 20130101; G05B 19/401 20130101; B24B 37/20
20130101; G05B 2219/45232 20130101 |
Class at
Publication: |
451/008 |
International
Class: |
B24B 49/00 20060101
B24B049/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 28, 2005 |
KR |
10-2005-0132649 |
Claims
1. A monitoring device of a chemical mechanical polishing
apparatus, comprising: a polishing pad; a plurality of
piezoelectric sensors formed at a rear surface of the polishing pad
for detecting a pressure applied to the polishing pad; a
communication section connected to the piezoelectric sensors for
transmitting data detected by the piezoelectric sensors; and a
display section for displaying the data transmitted from the
communication section.
2. The monitoring device according to claim 1, wherein each of the
plurality of piezoelectric sensors is a polymer sensor.
3. The monitoring device according to claim 1, wherein the
plurality of piezoelectric sensors are capable of detecting
pressure applied to the polishing pad according to a position of
the polishing pad.
4. The monitoring device according to claim 1, wherein the
communication section comprises a blue tooth, zigbee, infrared ray
communication, or ultra wide band transmission.
5. The monitoring device according to claim 1, wherein the
communication section comprises: a signal pass filter for receiving
and filtering data detected by the plurality of piezoelectric
sensors; an analog/digital converter for converting an analog
signal outputted from the signal pass filter into a digital signal;
and a blue tooth communication section for transmitting the digital
signal from the analog/digital converter to the display
section.
6. The monitoring device according to claim 1, wherein the
polishing pad is a polymer film.
7. The monitoring device according to claim 1, wherein the
polishing pad comprises regularly formed grooves.
8. A method for monitoring a chemical mechanical polishing
apparatus, comprising: providing a plurality of piezoelectric
sensors at a rear surface of a polishing pad; detecting a pressure
applied to the polishing pad by the plurality of piezoelectric
sensors; and transmitting data corresponding to pressure detected
by the plurality of piezoelectric sensors to a display section for
displaying the data.
9. The method according to claim 8, wherein transmitting the data
comprises using a wireless communication.
10. The method according to claim 9, wherein the wireless
communication uses a bluetooth module.
11. The method according to claim 8, wherein the polishing pad is
formed by a process comprising: preparing a master mold in which
negative-phase grooves are formed through an etching process;
mounting a polymer film to face the master mold; applying heat and
pressure to the master mold and the polymer film to form grooves in
the polymer film having a phase inverse to the negative phase
grooves of the master mold; and cooling the polymer film.
Description
RELATED APPLICATION
[0001] This application claims the benefit under 35 U.S.C. .sctn.
119(e), of Korean Patent Application 10-2005-0132649 filed Dec. 28,
2005, which is incorporated herein by reference in its
entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to a monitoring device of a
chemical mechanical polishing apparatus.
BACKGROUND OF THE INVENTION
[0003] In a process for manufacturing a semiconductor device, in
order to remove a metal thin film and an oxide layer, a chemical
mechanical polishing process is performed. In the chemical
mechanical polishing process, after a wafer has been mounted on an
upper portion of a polishing pad, the wafer is ground to a
predetermined thickness. Then, it is passed to a next stage.
[0004] The chemical mechanical polishing process is used as the
means for a planarization process of an insulating layer and a
damascene process of a metal layer.
[0005] A chemical mechanical polishing process is one of the
necessary semiconductor processes used to meet a planarization
demand according to the reduced size and increased integration of
semiconductor devices.
[0006] Such a chemical mechanical polishing process is divided into
a polishing step for polishing a wafer and a washing step. In the
polishing step, after a wafer is mounted on a polishing table and
is ground to a predetermined thickness, it is passed to the washing
step. The washing step washes the wafer polished in the polishing
step.
[0007] The following is a description of a chemical mechanical
polishing apparatus according to the related art with reference to
the accompanying drawings.
[0008] FIG. 1 is a perspective view showing a chemical mechanical
polishing apparatus according to the related art.
[0009] As shown in FIG. 1, the chemical mechanical polishing
apparatus includes a table 10, a polishing pad 20, a backing 50, a
retaining ring 40, a head 60, a slurry supply portion 80, and a
conditioner 70. The table 10 can rotate. The polishing pad 20 is
formed on the table 10. A wafer 30 is positioned at one side of the
polishing pad 20. The backing 50 and the retaining ring 40 protect
the wafer 30 from a pressure applied to an upper portion thereof
and support the wafer 30. The head 60 applies a force to an upper
portion of the backing 50 and rotates the backing 50. The slurry
supply portion 80 supplies a slurry to the polishing pad 20. The
conditioner 70 removes refuse discharged from the polishing step
and adjusts a surface of the polishing pad 20.
[0010] The polishing pad 20 of the chemical mechanical polishing
apparatus is composed of a polymer pad, which is often made of
polyurethane.
[0011] The chemical mechanical polishing apparatus moves the wafer
30 and dispenses a chemical solution and particles in the slurry
supply portion 80 to process a surface of the wafer 30.
Accordingly, properties of the slurry supply portion 80 and the
polishing pad 20 exert a significant influence upon the chemical
mechanical polishing process.
[0012] The polishing pad 20 directly contacts with the wafer 30. A
surface state of the polishing pad 30 has a significant influence
upon the polishing rate, uniformity, and defects.
[0013] Recent polishing pads have various constructions and
materials according to their purpose However, the most commonly
used polishing pad is manufactured by putting a heat curing agent
in a polymer with a microcapsule, and heating the resulting object
using an oven.
[0014] Grooves of various shapes for a floating of slurry are
formed at a surface of the manufactured polishing pad using a
cutter.
[0015] However, the polishing pad 20 of the chemical mechanical
polishing apparatus according to the related art has a non-uniform
surface. Since the polishing pad manufactured through the
aforementioned method has a non-uniform surface in a groove
formation step, it is not ground to a desired size
BRIEF SUMMARY
[0016] Accordingly, the present invention is directed to a
monitoring device and method of a chemical mechanical polishing
(CMP) apparatus that can address or substantially obviate one or
more problems due to limitations and disadvantages of the related
art.
[0017] An object of the present invention is to provide a
monitoring device and method of a chemical mechanical polishing
apparatus, which may form a uniform surface of a polishing pad.
Embodiments of the present invention can monitor a CMP process by
including piezoelectric sensors capable of monitoring a pressure
applied to a pad at a lower portion of the pad.
[0018] Additional advantages, objects, and features of the
invention will be set forth in part in the description which
follows and in part will become apparent to those having ordinary
skill in the art upon examination of the following or may be
learned from practice of the invention. The objectives and other
advantages of the invention may be realized and attained by the
structure particularly pointed out in the written description and
claims hereof as well as the appended drawings.
[0019] To achieve these objects and other advantages and in
accordance with the purpose of the invention, as embodied and
broadly described herein, there is provided a monitoring device of
a chemical mechanical polishing apparatus comprising: a polishing
pad; a plurality of piezoelectric sensors formed at a rear surface
of the polishing pad for detecting a pressure applied to the
polishing pad; a communication section connected to the
piezoelectric sensors for transmitting data detected by the
piezoelectric sensors; and a display section for displaying the
data transmitted from the communication section.
[0020] In another aspect of the present invention, there is
provided a method for monitoring a chemical mechanical polishing
apparatus comprising: providing a plurality of piezoelectric
sensors at a rear surface of a polishing pad; detecting a pressure
applied to the polishing pad by the piezoelectric sensors; and
transmitting data detected by the piezoelectric sensors to a
display section so that the display section displays the data.
[0021] It is to be understood that both the foregoing general
description and the following detailed description of the present
invention are exemplary and explanatory and are intended to provide
further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The accompanying drawings, which are included to provide a
further understanding of the invention and are incorporated in and
constitute a part of this application, illustrate embodiment(s) of
the invention and together with the description serve to explain
the principle of the invention.
[0023] FIG. 1 is a perspective view showing a chemical mechanical
polishing (CMP) apparatus according to the related art.
[0024] FIG. 2 is a cross-sectional view for describing a method for
forming a polishing pad of a CMP apparatus according to an
embodiment the present invention.
[0025] FIG. 3 is a photograph showing a surface of a polishing pad
according to the embodiment of FIG. 2.
[0026] FIG. 4 is a plan view showing a polymer sensor formed at a
rear surface of the polishing pad of a chemical mechanical
polishing apparatus according an embodiment of to the present
invention.
[0027] FIG. 5 is a photograph showing a surface of a polishing pad
according to the embodiment of FIG. 4.
[0028] FIG. 6 is a view showing a construction of the monitoring
device of the CMP apparatus according to an embodiment of the
present invention.
[0029] FIG. 7 is a block diagram showing a communication section in
the monitoring device of the CMP apparatus according to an
embodiment of the present invention.
[0030] FIG. 8 is a flow chart illustrating a monitoring method of a
CMP apparatus according to an embodiment of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0031] Reference will now be made in detail to the preferred
embodiments of the present invention, examples of which are
illustrated in the accompanying drawings. Wherever possible, the
same reference numbers will be used throughout the drawings to
refer to the same or like parts.
[0032] Hereinafter, a monitoring device and method of a chemical
mechanical polishing (CMP) apparatus according to an embodiment of
the present invention will be described with reference to the
accompanying drawings.
[0033] FIG. 2 is a cross-sectional view for showing a method for
forming a polishing pad of a CMP apparatus according to an
embodiment of the present invention.
[0034] With reference to FIG. 2, a master mold 112 can be mounted
on a first stage 100a. The master mold 112 can have a pattern with
a phase inverse to that of desired pad grooves.
[0035] In a specific embodiment, the master mold 112 can be formed
with grooves having the inverse phase pattern by performing an
etching process, and can be made of a metal SUS material.
[0036] A polymer film 111 can be mounted at an upper portion of a
second stage 100b to face the master mold 112.
[0037] The polymer film 111 is then placed in contact with the
master mold 112. When heat and pressure are applied to the polymer
film 111, grooves having an inverse phase from that of the master
mold 112 are formed in the polymer film.
[0038] Further, by cooling the polymer film 111 in which the
grooves are formed, a polishing pad is formed.
[0039] The polymer film 11 can be a material layer of the polishing
pad. Through the aforementioned process, a more uniform pressure
can be applied to the entire surface of the polymer film 111.
Therefore, grooves can be formed having a uniform surface as
compared to the pads formed by the cutter of the related art.
[0040] After the uniform grooves have been formed on the polymer
film 111, the second stage 100b can be separated from the polymer
film 11.
[0041] In a further embodiment the first and second stages 100a and
100b can be composed of a hot plate to which heat is applied. In
addition, the polishing pad can be formed in a vacuum state.
[0042] FIG. 3 is a photograph showing a surface of a polishing pad
formed by the embodiment of FIG. 2.
[0043] As shown in FIG. 3, the polishing pad of the CMP apparatus
of the present invention formed by the method of FIG. 2 includes
grooves 113 having a surface of a uniform arrangement.
[0044] FIG. 4 is a plan view showing a polymer sensor formed at a
rear surface of the polishing pad of a chemical mechanical
polishing apparatus according to an embodiment of the present
invention. FIG. 5 is a view showing a polymer film 111
incorporating the embodiment of FIG. 4 and the polymer sensor 120
formed at a rear surface of the polymer film 111.
[0045] Referring to FIG. 4, a plurality of polymer sensors 120 can
have a uniform arrangement and can be formed at a rear surface of
the polymer film 111.
[0046] The polymer sensor 120 can be made of a polyurethane
component device having a piezoelectric function. Because the main
component of the polymer sensor 120 is a polymer, it is not damaged
by an external pressurization and can be freely bent. Accordingly,
the polymer sensor 120 can be attached to a desired position of the
polymer film 111.
[0047] When an external voltage is applied to the polymer sensor
120, a displacement occurs in the polishing pad, and when the
displacement occurs in the polymer sensor 120, the polishing pad
generates a voltage.
[0048] Accordingly, it is understood that a pressure distribution
by regions in a surface of a wafer is provided during the CMP
process. By analyzing the pressure distribution, it is possible to
obtain an exact estimation during a set-up of the CMP process or
slurry development.
[0049] Referring to FIG. 5, the polishing pad can include a polymer
film 111 and piezoelectric polymer sensors 120. The polymer film
111 includes grooves, which are uniformly formed at a surface
thereof. The polymer sensors 120 can be regularly arranged at a
rear surface of the polymer film 111.
[0050] In a specific embodiment, each of the polymer sensors 120 is
a piezoelectric sensor. The polymer sensors 120 can be regularly
arranged at a lower, or rear, side of the polymer film 111.
[0051] Because the polymer sensors 120 do not make contact with the
wafer, the wafer is not damaged by the polymer sensors.
[0052] Each of the polymer sensors 120 functions to detect a
pressure state applied to the wafer according to an electric signal
from regions of the wafer.
[0053] The following is an explanation of piezoelectricity and a
formation method of the polymer sensors 120.
[0054] In general, piezoelectricity is a property of a noncentral
symmetry crystal material, and occurs by a dipole moment due to a
noncentral symmetry of a lattice. The piezoelectricity may convert
electric energy into dynamic energy, and perform an inverse
conversion.
[0055] Examples of piezoelectric material include lead xirconate
(PZT), barium titanate (BaTiO3), and zinc oxide (ZnO). In addition,
polymer materials having piezoelectricity include a copolymer of
poly vinylidene fluoride (PVDF or PVF2: .beta.-phase) and
vinylidene fluoride, and poly(vinylidene Fluoride-Co-Trifluoro
Ethylene): P(VDF-TrFE) copolymer.
[0056] Electrostriction is a phenomenon where strain or stress
occurs under a strong electric field. Although the principle of the
occurrence of the electrostriction is not known, it is a general
view that the strain occurs due to an electrostatic force generated
by a charge applied between flexible electrodes.
[0057] Such an electrostriction can convert an electric energy into
a dynamic energy but cannot perform a reverse conversion. The
strain occurs in proportion to a square of an intensity of an
applied electric field.
[0058] It has been reported that examples of electrostriction
materials are polyurethane (PU), silicon rubber, fluoro-silicon,
ethylene propylene, and polybutadiamine.
[0059] However, polyurethane has been used in clothing, shoes,
bags, and miscellaneous goods. In addition, polyurethane is used
for water-proofing, fire prevention, vibration isolation products,
waterproof cloth for industrial materials, and moisture
transpiration waterproof cloth for clothes. Here, a surface of
synthetic leather is coated with the polyurethane. Nonetheless, it
has not been reported that these products use the electrostriction
and piezoelectricity properties of polyurethane.
[0060] Polyurethane is a hemicrystalline polyer simultaneously
having a crystalline and an amorphous structure. In general,
polyurethane is composed of polyol, a chain extender, and
isocyanate.
[0061] Polyurethane is divided into a hard segment and a soft
segment according to a shape thereof. The polyol constitutes the
soft segment, and the chain extender and isocyanate are combined
with each other to form the hard segment.
[0062] The crystalline structure in the hard segment and the soft
segment is a main factor influencing piezoelectricity. The soft
segment is the main factor influencing the electrostriction of the
polyurethane. The polyurethane has both electrostriction and
piezoelectricity. In order to increase the piezoelectricity, the
crystalline degree of structural elements is reduced. Further, the
polyurethane having a maximized crystalline degree increases a
directional property of crystallines through an applied electric
field process.
[0063] Moreover, so as to improve the electrostriction, polyol
having no crystallines is synthesized by a solution polymerization
method, which is a first process for manufacturing the polyurethane
in order to increase the piezoelectricity. Further, components for
increasing an elastic force are added thereto.
[0064] The solution polymerization method is a polymerization
method that suitably melts a monomer in an inert solvent and adds a
soluble catalyst to polymerize the solution.
[0065] The polymer sensor 120 formed at a rear surface of the
polishing pad in the CMP apparatus according to an embodiment the
present invention can be made of polyurethane having a
piezoelectricity. The polyurethane having the piezoelectricity may
be obtained by synthesizing the polyurethane using
polytetramethelen ether grycol (PTMG) and by adding trimethylol
propane (TMP) to increase an elastic property. Here, the PTMG is a
polyol having no crystallines.
[0066] FIG. 6 is a schematic view showing a construction of the
monitoring device of the CMP apparatus according to an embodiment
the present invention.
[0067] As shown in FIG. 6, the monitoring device can include a
table 210, a polishing pad 220, a plurality of piezoelectric
sensors, a support member 230, a blue tooth module 240, and a
display section 250. The table 210 can rotate. The polishing pad
220 can be formed having a uniform surface on the table 210. The
plurality of piezoelectric sensors can be uniformly arranged at a
rear surface of the polishing pad 220 and spaced apart from each
other to detect a pressure applied to the polishing pad 220. The
support member 230 supports the table 210. The blue tooth module
240 can be installed at one side of the support member 230 to be
connected to the piezoelectric sensors, and transfers the pressure
data detected by the piezoelectric sensors. The display section 250
can display the data transferred through the blue tooth module
240.
[0068] FIG. 7 is a block diagram showing a communication section in
the monitoring device of the CMP apparatus according to an
embodiment of the present invention.
[0069] As shown in FIG. 7, the communication section can be a blue
tooth module. The blue tooth module 240 can include a signal pass
filter 241, an analog/digital (A/D) converter 242, and a blue tooth
communication section 243. The signal pass filter 241 receives the
pressure data detected by the piezoelectric sensors and removes
unnecessary noise included in the data. The A/D converter 242
converts the analog signal outputted from the signal pass filter
241 into a digital signal. The blue tooth communication section 243
transfers the digital signal from the A/D converter 242 to an
external computer.
[0070] The following is a description of the monitoring method of
the CMP apparatus according to an embodiment of the present
invention.
[0071] FIG. 8 is a flow chart illustrating a monitoring method of a
CMP apparatus according to an embodiment of the present
invention.
[0072] As shown in FIG. 8, first, a polishing pad having a uniform
surface can be formed (S100). The polishing pad can be formed using
the method described with respect to FIG. 2.
[0073] Next, a plurality of piezoelectric sensors can be arranged
at a rear surface of the polishing pad and spaced apart from each
other by a predetermined distance (S200).
[0074] The piezoelectric sensors detect a pressure applied to the
polishing pad (S300).
[0075] Next, the data detected by the piezoelectric sensors can be
transmitted to a display section of an external computer to be
monitored (S400).
[0076] Here, a procedure of transmitting the data to the display
section will now be explained in detail with reference to FIG.
7.
[0077] That is, the signal pass filter 241 receives the data
obtained by the piezoelectric sensors and removes unnecessary noise
included in the data. The A/D converter 242 converts the analog
signal being an output signal of the signal pass filter 241 into a
digital signal, which may be calculated by a computer.
[0078] Next, the blue tooth communication section 243 transmits the
digital signal from the A/D converter 242 to the display section
250 so that the display section 250 displays the digital signal.
The blue tooth communication section 243 is a device capable of
transmitting and receiving a signal in a wireless manner.
[0079] Since the CMP apparatus is a rotating piece of equipment, a
ring type jig (slip rig) is required to transmit the data to an
exterior when not using a wireless communication in order to not be
influenced by a rotation. However, the ring type jig can have an
influence upon the rotation of the CMP apparatus. Therefore, when a
wireless communication device is used, it can easily transmit the
data to an external computer.
[0080] As described above, the transmitted data is transmitted to a
computer through a receiver of a blue booth device. Accordingly,
the receiver calculates and displays a required pressure
distribution of an entire surface of a wafer.
[0081] However, it should be noted that while the blue tooth device
is explained as an example of a wireless communication device, used
in embodiments of the subject invention, the present invention is
not limited thereto. For example, any wireless communication method
can be used, including zigbee, infrared ray communication, and
ultra wide band.
[0082] As is seen from the forgoing description, the monitoring
device and method of a chemical mechanical polishing apparatus
according to embodiments of the present invention can have
following effects.
[0083] That is, the present invention may prevent an original
signal from being distorted due to a touch-signal transmission
manner such as a slip ring by using a wireless communication
device. Further, embodiments of the present invention can provide
exact detection of a pressure distribution of a pad surface
according to a CMP process condition and a process condition at a
set-up. In addition, the present invention may remove a random
effect occurring due to a non-uniformity of the pad surface during
an estimation of a slurry in order to exactly estimate the
slurry.
[0084] It will be apparent to those skilled in the art that various
modifications and variations can be made in the present invention.
Thus, it is intended that the present invention covers the
modifications and variations of this invention provided they come
within the scope of the appended claims and their equivalents.
* * * * *