U.S. patent application number 12/464223 was filed with the patent office on 2010-11-18 for system and method for conditioning chemical mechanical polishing apparatus using multiple conditioning disks.
This patent application is currently assigned to TAIWAN SEMICONDUCTOR MANUFACTURING CO., LTD.. Invention is credited to Chyi Shyuan CHERN, Soon Kang HUANG, Kun-Ku HUNG, Zin-Chang WEI.
Application Number | 20100291840 12/464223 |
Document ID | / |
Family ID | 43068890 |
Filed Date | 2010-11-18 |
United States Patent
Application |
20100291840 |
Kind Code |
A1 |
HUANG; Soon Kang ; et
al. |
November 18, 2010 |
SYSTEM AND METHOD FOR CONDITIONING CHEMICAL MECHANICAL POLISHING
APPARATUS USING MULTIPLE CONDITIONING DISKS
Abstract
A chemical mechanical polishing (CMP) apparatus provides for
polishing semiconductor wafers and for conditioning the polishing
pad of the CMP apparatus using multiple conditioning disks at the
same time. The conditioning disks may be moved together or
independently along the surface of polishing pad to condition the
entire surface of the rotating polishing pad.
Inventors: |
HUANG; Soon Kang; (Hsin Chu,
TW) ; HUNG; Kun-Ku; (Hemei Township, TW) ;
WEI; Zin-Chang; (Hsin-Chu City, TW) ; CHERN; Chyi
Shyuan; (Taipei, TW) |
Correspondence
Address: |
DUANE MORRIS LLP (TSMC);IP DEPARTMENT
30 SOUTH 17TH STREET
PHILADELPHIA
PA
19103-4196
US
|
Assignee: |
TAIWAN SEMICONDUCTOR MANUFACTURING
CO., LTD.
Hsin-Chu City
TW
|
Family ID: |
43068890 |
Appl. No.: |
12/464223 |
Filed: |
May 12, 2009 |
Current U.S.
Class: |
451/56 ;
451/72 |
Current CPC
Class: |
B24B 53/017 20130101;
B24B 53/003 20130101 |
Class at
Publication: |
451/56 ;
451/72 |
International
Class: |
B24B 1/00 20060101
B24B001/00; B24B 7/07 20060101 B24B007/07 |
Claims
1. A method for performing chemical mechanical polishing (CMP) on a
substrate, comprising: simultaneously polishing said substrate or a
material disposed over said substrate, on a polishing pad in a CMP
apparatus and conditioning said polishing pad with more than one
separately controllable conditioning member by urging a diamond
grit surface of each said conditioning member against said
polishing pad.
2. The method as in claim 1, further comprising rotating each said
diamond grit surface of each said conditioning member.
3. The method as in claim 1, wherein each said conditioning member
comprises a disk and wherein said diamond grit surface forms a
surface of said disk.
4. The method as in claim 1, wherein said polishing pad is disposed
on and in fixed relation with respect to a platen, and said
polishing comprises rotating said platen.
5. The method as in claim 4, further comprising simultaneously
sliding each said conditioning member along a radial direction of
said polishing pad including sliding a first one of said
conditioning members only along a first segment of a radius of said
polishing pad and sliding a second one of said conditioning members
along a further segment of said radius of said polishing pad such
that all locations of said polishing pad are conditioned.
6. The method as in claim 1, further comprising translating each
said conditioning member against a surface of said polishing pad,
wherein said more than one conditioning member are coupled to one
another.
7. The method as in claim 1, wherein said conditioning said
polishing pad with more than one separately controllable
conditioning member comprises translating said conditioning members
with respect to each other and against a surface of said polishing
pad.
8. A method for conditioning a polishing pad of a chemical
mechanical polishing (CMP) apparatus comprising simultaneously
urging more than one separately controllable conditioning member
against a rotating polishing pad of said CMP apparatus, each said
conditioning member including a conditioning surface contacting
said rotating polishing pad.
9. The method as in claim 8, wherein each said conditioning surface
comprises a diamond grit surface of a disk.
10. The method as in claim 8, wherein said simultaneously urging
comprises independently translating each said conditioning surface
along a surface of said rotating polishing pad.
11. The method as in claim 8, further comprising sliding each said
conditioning surface against a surface of said polishing pad,
wherein said conditioning members are coupled to one another.
12. The method as in claim 8, further comprising polishing a
material formed over a substrate, on said rotating polishing pad at
the same time as said simultaneously urging.
13. The method as in claim 8, further comprising simultaneously
sliding a first one of said conditioning surfaces along a first
segment of a radius of said rotating polishing pad and separately
sliding a second one of said conditioning surfaces against a
further segment of a radius of said rotating polishing pad such
that said entire polishing pad is conditioned.
14. A chemical mechanical polishing (CMP) apparatus comprising: a
polishing pad fixedly disposed on a rotatable platen; a carrier
that secures a semiconductor wafer that is being polished, against
said polishing pad; and more than one discrete conditioning
fixture, each being individually controllable and including a
conditioning disk in contact with said polishing pad.
15. The CMP apparatus as in claim 14, wherein each said
conditioning disk has a diamond grit surface and each said discrete
conditioning fixture comprises movement means for causing each said
associated conditioning disk to slide across said polishing
pad.
16. The CMP apparatus as in claim 15, wherein said discrete
conditioning fixtures are coupled to one another by an expandable
and retractable member.
17. The CMP apparatus as in claim 15, wherein said discrete
conditioning fixtures are capable of independent translational
motion with respect to one another.
18. The CMP apparatus as in claim 14, further comprising means for
exerting a force directing each said conditioning disk against said
polishing pad.
19. The CMP apparatus as in claim 14, wherein each said
conditioning disk includes one of bristles and a diamond grit
surface and each said discrete conditioning fixture is
rotatable.
20. The CMP apparatus as in claim 14, wherein said semiconductor
wafer includes a diameter of about 450 mm and each said
conditioning disk is a surface of a disk having a diameter of about
100 mm.
Description
FIELD OF THE INVENTION
[0001] The present invention relates, most generally, to
semiconductor device manufacturing equipment. More particularly,
the present invention relates to a chemical mechanical polishing
(CMP) apparatus and methods for chemical mechanical polishing of
semiconductor wafers and for conditioning the CMP apparatus.
BACKGROUND
[0002] In today's rapidly advancing semiconductor manufacturing
industry, chemical mechanical polishing (CMP) is an advantageous
and favored way of planarizing and polishing semiconductor
substrates to remove excess materials from over a surface of the
semiconductor substrate. In this manner, damascene techniques may
be used to form conductive features within openings such as
trenches, vias or contacts formed in insulating layers. In
damascene processing, a bulk material such as a conductive material
is formed over an insulating layer and within such openings formed
within the insulating layer, then removed from over the top surface
of the insulating layer using chemical mechanical polishing. The
resulting structure includes the conductive materials filling the
various openings and extending up to the top surface of the
insulating layer after the excess conductive materials have been
removed from over the top of the insulating layer.
[0003] Chemical mechanical polishing involves a polishing pad and
includes mechanical and chemical components. The polishing pad
rotates and the wafer surface desired to be polished is brought
into contact with the rotating polishing pad at a wafer polishing
location. The wafer, i.e. substrate, advantageously rotates to
enhance polishing. A dispenser head dispenses a polishing slurry
onto the polishing pad. The polishing pad is typically made of
polyurethane and the pad surface is typically permeated with the
polishing slurry that contains both submicron abrasives and
chemicals. The quality and uniformity of the polishing pad surface
is critical to providing a uniform polish to the wafers being
polished. In particular, the surface roughness of the polishing pad
must be maintained in the same condition as several wafers are
successively polished using the apparatus.
[0004] A conditioning process is used to condition the polishing
pad surface and to maintain it in a desired and uniform state. The
conditioning rejuvenates the polishing pad surface, removes debris
from the polishing pad and maintains a stable removal rate. The
conditioning member is typically a disk with a diamond grit surface
that is pressed up against the rotating polishing pad during
conditioning. The conditioning operation may take place
concurrently with the wafer polishing operation or before or after
the wafer polishing operation.
[0005] Because the polishing pad is typically much larger than
conventional conditioning disks, the conditioning disk is typically
slid along the polishing pad surface while the polishing pad
rotates so that the entire polishing pad surface can be conditioned
by the comparatively small conventional conditioning disk that may
be about 4 inches in diameter or less. Typically, a particular
number of scans or sweeps across the radius of the polishing pad,
are desired to be made in a given time frame to provide a desired
level of conditioning. As the size of the polishing pad increases,
the scan speed of the conditioning disk being swept across the
polishing pad surface must increase in order to maintain a given
number of sweeps per minute. As the speed of the conditioning disk
sliding across the surface increases, however, the quality of the
condition operation diminishes.
[0006] Conditioning the entire polishing pad surface becomes more
challenging as semiconductor wafer sizes increase. The increase in
semiconductor wafer sizes mandates a corresponding increase in the
size of the polishing pad. For example, wafer sizes are now as
large as 450 millimeters in diameter and such wafers are polished
using polishing pads that may be as great as 1 meter to 45 inches
in diameter. This increased size requires a greater surface area to
be covered during the conditioning process, as above. Conditioning
the entire polishing pad surface is particularly challenging due to
the difficulty of manufacturing diamond grit surfaces of the
conditioning disks at larger dimensions. It is difficult to
maintain the uniformity and quality of diamond grit conditioning
disks that are greater than about four inches in diameter because
such disks must be substantially completely flat and any deviation
from planarity will cause diamond grit to become disengaged from
the surface, causing contamination and scratches on the polishing
pad and on the wafer surface.
[0007] It is therefore important to provide a system and method for
conditioning a CMP polishing pad as the size of the polishing pad
increases. The present invention addresses these shortcomings and
challenges.
SUMMARY OF THE INVENTION
[0008] To address these and other needs and in view of its
purposes, the present invention provides, in one aspect, a method
for performing chemical mechanical polishing (CMP) on a substrate.
The method includes simultaneously polishing the substrate or a
material formed over the substrate, on a polishing pad in a CMP
apparatus and conditioning the polishing pad with more than one
separately controllable conditioning member by urging a diamond
grit surface of each of the conditioning members against the
polishing pad.
[0009] According to another aspect, provided is a method for
conditioning a polishing pad of a CMP apparatus comprising
simultaneously urging more than one separately controllable
conditioning surface of a conditioning member against a rotating
polishing pad of the CMP apparatus.
[0010] According to yet another aspect, provided is a chemical
mechanical polishing apparatus. The apparatus includes a polishing
pad fixedly disposed on a rotatable platen. The apparatus further
includes a carrier that secures a semiconductor wafer that is being
polished, against the polishing pad. The chemical mechanical
polishing apparatus further includes more than one discrete,
separately controllable conditioning fixture, each including a
conditioning disk in contact with the polishing pad.
BRIEF DESCRIPTION OF THE DRAWING
[0011] The present invention is best understood from the following
detailed description when read in conjunction with the accompanying
drawing. It is emphasized that, according to common practice, the
various features of the drawing are not necessarily to scale. On
the contrary, the dimensions of the various features are
arbitrarily expanded or reduced for clarity. Like numerals denote
like features throughout the specification and drawing.
[0012] FIG. 1 is a perspective view illustrating aspects of a
chemical mechanical polishing apparatus according to the
invention;
[0013] FIG. 2 is a perspective view illustrating other aspects of a
multiple conditioning disk CMP apparatus according to the
invention;
[0014] FIG. 3 is a top view illustrating an exemplary arrangement
of multiple conditioning members according to an aspect of the
invention; and
[0015] FIG. 4 is a top view illustrating another exemplary
arrangement of multiple conditioning members according to an aspect
of the invention.
DETAILED DESCRIPTION
[0016] The invention provides for using multiple conditioning disks
to condition a polishing pad in a CMP apparatus at the same time.
The conditioning may take place in-situ, i.e. at the same time as
the wafer polishing operation is being carried out, or it may take
place before or after the wafer polishing operation is carried out
on a semiconductor wafer. The invention finds application for
various sized polishing pads and for polishing semiconductor wafers
of various sizes. The multiple conditioning disk arrangement and
method may be used in conjunction with various orientations and
arrangements of CMP apparatuses. The conditioning disks may be
separately controllable.
[0017] FIG. 1 is a perspective view showing rotatable platen 1 with
polishing pad 3 including surface 7, fixedly secured to platen 1.
Platen 1 rotates along direction of rotation 5 and at any of
various suitable speeds. Wafer carrier 9 positions wafer 11 (shown
separately) on polishing pad 3 at the polishing location. Polishing
pad 3 may be made of polyurethane or other suitable materials.
Force F applied along force direction 15 urges wafer carrier 9
downward toward and against polishing pad 3. Although not visible
in FIG. 1, wafer 11 will be disposed underneath wafer carrier 9 at
interface 13 between wafer carrier 9 and polishing pad 3. Wafer
carrier 9 advantageously rotates along direction 29. This rotation
may take place at the same time that platen 1 rotates along
rotation direction 5. Slurry dispenser 19 dispenses slurry 19 at
dispense location 21. Due to rotation, fresh slurry 23 spreads
beneath wafer carrier 9 and therefore wafer 11 and spent slurry 25
exits the polishing location.
[0018] Also illustrated in FIG. 1 are two conditioning members 31.
Although not illustrated as being positioned on polishing pad 3 in
the illustrated embodiment, it should be understood and will be
subsequently illustrated that both of conditioning members 31 may
be disposed on surface 7 of polishing pad 3 simultaneously and at
various locations and disposed various distances from one another.
Additional conditioning members 31, i.e. more than two, may also be
disposed on surface 7 of polishing pad 3 simultaneously.
Conditioning members 31 each include a conditioning disk 33 that
forms the bottom portion thereof in the illustration of FIG. 1.
Exposed conditioning surface 35 of conditioning disk 33 is
preferably formed of a commonly known diamond grit material
advantageously used to condition polishing pad 3. In other
exemplary embodiments, conditioning surface 35 may be formed of
other suitable materials such as scouring materials or it may
include bristles such as a brush. Conditioning disk 33 may have a
diameter of about 4 inches or 100 mm in one exemplary embodiment,
but other sizes may be used in other exemplary embodiments. When
pressed against polishing pad 3, conditioning disks 33 and
conditioning members 31 may rotate about axis 37 along direction of
rotation 39. In some exemplary embodiments, conditioning disks 33
may not rotate. Various conventional means may be used to urge
conditioning disk 33 and conditioning surface 35 against surface 7
of polishing pad 3 and to effect the rotation.
[0019] When conditioning disk 33 is disposed against polishing pad
3, the associated conditioning member 31 may be moved, preferably
slid, along polishing pad 3 such that the entire surface 7 of
rotating polishing pad 3 is conditioned. The conditioning disks 33
and conditioning member 31 may be separately controllable and may
rotate at the same or different speeds and may be translated
separately or in unison along surface 7 of polishing pad 3.
[0020] FIG. 2 is a perspective view showing another aspect of the
multiple conditioning disk CMP apparatus according to the invention
showing a plurality (two) of conditioning disks 33 on polishing pad
3. Each conditioning disk 33 is retained by an associated
conditioning member 31 not illustrated in FIG. 2. According to one
exemplary embodiment, the entire surface 7 of polishing pad 3 can
be conditioned as platen 1 and polishing pad 3 rotate along
direction 5, by sliding, i.e. translating, either or both of
conditioning disks 33 along the direction of exemplary radius 47.
Either or both of conditioning disks 33 may be moved both
proximally toward and distally away from center point 43 of
polishing pad 3, i.e. back and forth along a radius of polishing
pad 3. According to one exemplary embodiment, each conditioning
disk 33 may move along a scan direction along radius 47. According
to one particular exemplary embodiment, one conditioning disk 33
may slide forward and backward, or backward and forward, along
segment 46 of radius 47 and a second conditioning disk 33 may slide
forward and backward along segment 48 of radius 47. In this manner,
the entire radius of polishing pad 3, and hence the entire rotating
polishing pad 3, will be scanned by one of conditioning disks 33.
Conditioning disks 33 may move in unison or with respect to each
other. As the scan speed of a conditioning disk 33 being slid along
surface 7 increases, the quality of conditioning degrades. As such,
according to the multi-conditioning disk arrangement, a desired
number of conditioning scans per minute can be achieved at
essentially half the scan speed because each conditioning disk 33
only covers about half of the scan distance along radius 47 when
two conditioning disks 33 are used. This is especially advantageous
as polishing pad 3 sizes increase such as to 45 inches or greater.
According to various exemplary embodiments, the respective
conditioning disks 33 may move along the same or different,
angularly spaced radius lines, to cover the entire polishing pad 3.
According to other exemplary embodiments conditioning disks 33 may
move in other directions to scan the entire rotating polishing pad
3.
[0021] Now turning to FIG. 3, conditioning members 31 disposed on
polishing pad 3 are coupled to each other and conditioning arm 53
by way of mechanical coupling 55. Conditioning members 31 may be
spaced apart by various suitable distances. Mechanical coupling 55
may be pivotable about conditioning arm 53 or it may be fixed with
respect to conditioning arm 53. Mechanical coupling 55 may be rigid
or dynamically expandable and retractable, allowing for relative
motion between conditioning member 31. Conventional means are used
to apply force downward, urging the conditioning disks disposed
beneath conditioning members 31, against surface 7 of polishing pad
3. With conditioning members 31 disposed against polishing pad 3,
conditioning arm 53 may effectuate movement of conditioning members
31 along any direction in the x-y plane of surface 7 of polishing
pad 3, or rotationally as indicated by arrow 59. Conventional
mechanical means may be used. According to this exemplary
embodiment, the speed of rotation of the conditioning members 31
may be separately controllable.
[0022] FIG. 4 shows another exemplary arrangement in which
conditioning members 31 are capable of independent movement. Each
conditioning member 31 is coupled to a corresponding conditioning
arm 61 and each conditioning arm 61 may be coupled to separate
mechanical movement means that separately move conditioning arms 61
and corresponding conditioning members 31 in any direction along
polishing pad 3 to carry out the conditioning operation. In FIGS. 3
and 4, it should understood that each conditioning member 31 may be
rotatable about its axis and such rotation may take place during
the translational movement in which conditioning members 31 are
slid along surface 7 of polishing pad 3.
[0023] Dimensions of the features may vary according to various
exemplary embodiments. According to one exemplary embodiment, the
diameter of conditioning disks 33 may be about four inches or less
to advantageously maintain a substantially flat and defect free
diamond grit or other polishing surface 35. Wafer 11 may include
various diameters ranging from 100 mm to 450 mm and polishing pad 3
may have a diameter of up to about 1 meter or 45 inches in various
exemplary embodiments.
[0024] According to an exemplary method of the invention,
conditioning of polishing pad 3 may take place during, before or
after, the wafer polishing operation in which a wafer is retained
within wafer carrier 9 and polished. Conditioning may involve
simultaneous rotation of one or more of the conditioning members 31
and translation of conditioning members 31 along polishing pad 3 in
any direction, straight or curved.
[0025] According to one exemplary embodiment, the conditioning arm
53 or conditioning arms 61 may be coupled to a programmable
controller that controls the motion of the conditioning arm and
hence the associated conditioning member or members 31, i.e. the
rotational speed of conditioning member 31 and the location and
translational speed of conditioning member 31 being slid along
polishing pad 3. According to one exemplary embodiment, such a
controller may be programmed to cause a first conditioning member
31 to slide along a first radial segment of polishing pad 3 and to
also cause a second conditioning member 31 to slide along another
radial segment of polishing pad 3 such that each conditioning
member 31 moves radially inward and outward but each scans only
about half the radial distance such that, together, the entire
radius of the polishing pad is scanned and hence the entire
rotating polishing pad conditioned. According to another exemplary
embodiment, there may be greater than the two conditioning members
used at the same time and they may be positioned at various
locations on the polishing pad with respect to the wafer polishing
location, i.e. proximate or distal to the polishing location. The
programmable controller may control the conditioning members
separately or collectively.
[0026] The preceding merely illustrates the principles of the
invention. It will thus be appreciated that those skilled in the
art will be able to devise various arrangements which, although not
explicitly described or shown herein, embody the principles of the
invention and are included within its spirit and scope.
Furthermore, all examples and conditional language recited herein
are principally intended expressly to be only for pedagogical
purposes and to aid in understanding the principles of the
invention and the concepts contributed by the inventors to
furthering the art, and are to be construed as being without
limitation to such specifically recited examples and conditions.
Moreover, all statements herein reciting principles, aspects, and
embodiments of the invention, as well as specific examples thereof,
are intended to encompass both structural and functional
equivalents thereof. Additionally, it is intended that such
equivalents include both currently known equivalents and
equivalents developed in the future, i.e., any elements developed
that perform the same function, regardless of structure.
[0027] This description of the exemplary embodiments is intended to
be read in connection with the figures of the accompanying drawing,
which are to be considered part of the entire written description.
In the description, relative terms such as "lower," "upper,"
"horizontal," "vertical," "above," "below," "up," "down," "top" and
"bottom" as well as derivatives thereof (e.g., "horizontally,"
"downwardly," "upwardly," etc.) should be construed to refer to the
orientation as then described and/or as shown in the drawing under
discussion. These relative terms are for convenience of description
and do not require that the apparatus be constructed or operated in
a particular orientation. Terms concerning attachments, coupling
and the like, such as "connected" and "interconnected," refer to a
relationship wherein structures are secured or attached to one
another either directly or indirectly through intervening
structures, as well as both movable or rigid attachments or
relationships, unless expressly described otherwise.
[0028] Although the invention has been described in terms of
exemplary embodiments, it is not limited thereto. Rather, the
appended claims should be construed broadly, to include other
variants and embodiments of the invention, which may be made by
those skilled in the art without departing from the scope and range
of equivalents of the invention.
* * * * *