U.S. patent application number 11/730890 was filed with the patent office on 2007-08-02 for method of processing a substrate.
This patent application is currently assigned to KABUSHIKI KAISHA TOSHIBA. Invention is credited to Atsushi Shigeta, Gen Toyota, Hiroyuki Yano.
Application Number | 20070178701 11/730890 |
Document ID | / |
Family ID | 35046646 |
Filed Date | 2007-08-02 |
United States Patent
Application |
20070178701 |
Kind Code |
A1 |
Toyota; Gen ; et
al. |
August 2, 2007 |
Method of processing a substrate
Abstract
There is disclosed a method of processing a substrate, which
comprises applying a surfactant or a water soluble polymer agent
onto a surface of a substrate to be processed, and sliding a
circumferential portion of the substrate and a polishing member
against each other to polish the circumferential portion of the
substrate.
Inventors: |
Toyota; Gen; (Yokohama-shi,
JP) ; Shigeta; Atsushi; (Fujisawa-shi, JP) ;
Yano; Hiroyuki; (Yokohama-shi, JP) |
Correspondence
Address: |
FINNEGAN, HENDERSON, FARABOW, GARRETT & DUNNER;LLP
901 NEW YORK AVENUE, NW
WASHINGTON
DC
20001-4413
US
|
Assignee: |
KABUSHIKI KAISHA TOSHIBA
|
Family ID: |
35046646 |
Appl. No.: |
11/730890 |
Filed: |
April 4, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11088199 |
Mar 24, 2005 |
7217662 |
|
|
11730890 |
Apr 4, 2007 |
|
|
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Current U.S.
Class: |
438/690 ;
257/E21.224; 257/E21.237 |
Current CPC
Class: |
H01L 21/30625 20130101;
H01L 21/02043 20130101; H01L 21/02021 20130101; B24B 37/02
20130101; B24B 9/065 20130101 |
Class at
Publication: |
438/690 |
International
Class: |
H01L 21/302 20060101
H01L021/302; H01L 21/461 20060101 H01L021/461 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 24, 2004 |
JP |
2004-087417 |
Claims
1-18. (canceled)
19. A program of processing a substrate readable and executable by
a computer, comprising: applying a surfactant or a water soluble
polymer agent onto a surface of a substrate to be processed; and
sliding a circumferential portion of the substrate and a polishing
member against each other to polish the circumferential portion of
the substrate.
20. A program of processing a substrate readable and executable by
a computer, according to claim 19, further comprising cleaning the
surface of the substrate, after the circumferential portion of the
substrate is polished.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority from prior Japanese Patent Application No. 2004-087417,
filed Mar. 24, 2004, the entire contents of which are incorporated
herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a method of processing a
substrate for removing surface roughness that occurs on a
circumferential portion (bevel portion and edge portion) of a
substrate to be processed, such as a semiconductor wafer, and films
that adhere to the circumferential portion of the substrate to be
processed to become stain sources.
[0004] 2. Description of the Related Art
[0005] In recent years, along with the miniaturization of
semiconductor elements and the high packing density of
semiconductor devices, management of particles has become more
important. As one of the big problems in managing particles, there
is the problem of dust occurrence arising from surface roughness
that occurs on bevel portion and edge portion of a semiconductor
wafer (semiconductor substrate) in processes of manufacturing a
semiconductor device. Herein, the bevel portion means a wafer
portion having a slanted cross section at an end portion of the
semiconductor wafer, and the edge portion means a flat surface
wafer portion of around several millimeters from the bevel portion
toward the internal side of the wafer.
[0006] For example, in a reactive ion etching (RIE) step of forming
trenches (deep trenches) of a trench capacitor on a surface of an
Si wafer, a by-product generated in etching adheres to the bevel
portion and the edge portion of the wafer. Then, because this
by-product works as an etching mask, thorn-shaped protrusions are
likely to be formed on the bevel portion and the edge portion of
the wafer (protrusions shown by reference numeral 25 in FIG. 3). In
particular, when attempt is made to form an extremely large deep
trench whose opening diameter is of a sub micron order, and whose
aspect ratio is several tens, the above-mentioned thorn-shaped
protrusions are apt to occur at the circumferential portion due to
its process conditions.
[0007] Although the height of thorn-shaped protrusions varies with
their positions on the wafer, it becomes nearly 10 .mu.m at
maximum, and these protrusions are broken at the time of transfer
or processes of the wafer, and become causes of particles. Since
such particles lead to the decrease of the yield of a semiconductor
device to be manufactured, it is necessary to remove the
thorn-shaped protrusions formed on the bevel portion and edge
portion.
[0008] Conventionally, in order to remove such thorn-shaped shaped
protrusions and the likes, a chemical dry etching (CDE) method is
employed. However, since the CDE method is of isotropic etching,
and therefore, even if low thorn-shaped protrusions are removed
completely, high thorn-shaped protrusions can not completely be
removed, and some thereof are left unremoved. As a consequence,
concaves and convexes according to the uneven height of the
thorn-shaped protrusions are inevitably formed on the wafer. Dust
easily collects in these concaves and convexes at the time of
machine processing such as chemical mechanical polishing (CMP) to
be carried out in later processes, which becomes a problem.
Further, the processing time required for the CDE process per wafer
is as long as normally 5 minutes or more. Accordingly, the CDE
process leads to decline the throughput, and also increases raw
material costs, which is a problem.
[0009] Further, in processes of manufacturing a semiconductor
device, raw material films adhering to bevel portion and edge
portion of a wafer become sources of stain. Therefore, it is
required to remove the material films, however, in the CDE method,
it is difficult to easily remove the material films.
[0010] Recently, in order to remove surface roughness that occurred
on a circumferential portion of a wafer and films that adhere to
the circumferential portion to become stain sources, a method of
polishing the circumferential portion is carried out (as disclosed
in, for example, Jpn. Pat. Appln. KOKAI Publication No.
2003-234314). In this method, a wafer is rotated and also a
polishing member such as a polishing tape is contacted to a side
surface of the wafer, thereby polishing the circumferential portion
of the wafer. In this manner, it is possible to remove surface
roughness that occurs on the circumferential portion of the wafer
and films that adhere to the circumferential portion to become
stain sources, in a short time.
[0011] However, this kind of method has the following problem.
Namely, when a substrate side surface is polished, fine Si
particles of the main component of the substrates polishing
particles of the polishing tape and the like scatter. Especially,
when the substrate surface is hydrophobic, these particles adhere
firmly to the surface. Therefore, even if physical cleaning of the
substrate surface is carried out after completion of polishing
process, particles can hardly be removed. Consequently, there is a
problem on reliability of a semiconductor device to be
manufactured. Furthermore, the method leads to the decline in
yield.
SUMMARY OF THE INVENTION
[0012] According to an aspect of the present invention, there is
provided a method of processing a substrate, comprising:
[0013] applying a surfactant or a water soluble polymer agent onto
a surface of a substrate to be processed; and
[0014] sliding a circumferential portion of the substrate and a
polishing member against each other to polish the circumferential
portion of the substrate.
[0015] According to another aspect of the present invention, there
is provided a method of processing a substrate in which a polishing
member is contacted and pressed onto a circumferential portion of a
substrate to be processed, while the substrate is rotated by
rotating a substrate holding portion which holds the substrate
thereon, and pure water or chemical solution is supplied onto a
contact portion between the circumferential portion of the
substrate and the polishing member, to polish the circumferential
portion of the substrate, the method comprising:
[0016] applying a surfactant or a water soluble polymer agent onto
a surface of the substrate to be processed in advance.
[0017] According to a further aspect of the present invention,
there is provided a program of processing a substrate readable and
executable by a computer, comprising:
[0018] applying a surfactant or a water soluble polymer agent onto
a surface of a substrate to be processed; and
[0019] sliding a circumferential portion of the substrate and a
polishing member against each other to polish the circumferential
portion of the substrate.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0020] FIG. 1 is a schematic perspective view showing a
configuration of a polishing device for use in substrate processing
by a substrate processing method according to an embodiment of the
present invention;
[0021] FIG. 2 is a cross sectional view showing a substrate
structure in a step of a substrate processing method according to
the embodiment of the present invention, for explaining the
substrate processing method;
[0022] FIG. 3 is a cross sectional view showing a substrate
structure in a step following the step of FIG. 2 of a substrate
processing method according to the embodiment of the present
invention, for explaining the substrate processing method;
[0023] FIG. 4 is a cross sectional view showing a substrate
structure in a step following the step of FIG. 3 of a substrate
processing method according to the embodiment of the present
invention, for explaining the substrate processing method;
[0024] FIG. 5 is a cross sectional view showing a substrate
structure in a step following the step of FIG. 4 of a substrate
processing method according to the embodiment of the present
invention, for explaining the substrate processing method;
[0025] FIG. 6 is a cross sectional view showing a substrate
structure in a step following the step of FIG. 5 of a substrate
processing method according to the embodiment of the present
invention, for explaining the substrate processing method;
[0026] FIG. 7 is a characteristic chart showing decreasing effects
of residual particles on a substrate by use of the substrate
processing method according to the embodiment of the present
invention;
[0027] FIG. 8 is a flow chart of processing a substrate with
instructions from a control section;
[0028] FIG. 9 is a flow chart of processing a substrate with
instructions from a control section; and
[0029] FIG. 10 is a flow chart of cleaning a substrate carried out
following the process flows shown in FIGS. 8 and 9.
DETAILED DESCRIPTION OF THE INVENTION
[0030] An embodiment of the present invention will be explained by
reference to the accompanying drawings.
EMBODIMENT
[0031] FIG. 1 is a schematic perspective view showing a
configuration of a polishing device for use in substrate processing
by a substrate processing method according to an embodiment of the
present invention.
[0032] In FIG. 1, reference numeral 11 is a substrate holding
portion capable of rotational movement as one of plane movements. A
substrate 12 to be processed, such as a semiconductor wafer, is
held on the substrate holding portion 11. The substrate holding
portion 11 is driven by a motor, not shown, to rotate with a
vertical axis at its rotational center. The diameter of the
substrate holding portion 11 is smaller than that of the substrate
12, and therefore, a circumferential portion of the substrate 12
protrudes outward from the substrate holding portion 11.
[0033] A polishing tape 13, that is used for polishing the
circumferential portion of the substrate 12, is attached to a
polishing head 14 that is movable in the horizontal direction (the
direction perpendicular to a rotating axis of the substrate holding
portion 11). When the polishing head 14 is moved to the substrate
12 side, the polishing tape 13 is contacted and pressed onto a side
surface of the substrate 12.
[0034] Further, reference numeral 15. in FIG. 1 is a pure water
supply nozzle for supplying pure water onto the substrate 12. Pure
water is dripped onto the center of the surface of the rotating
substrate 12, whereby pure water is supplied to the contact portion
between the substrate 12 and the polishing tape 13 by centrifugal
force generated by the rotation. A polishing solution may be also
employed, in the place of pure water.
[0035] In addition, reference numeral 16 in FIG. 1 is a surfactant
supply nozzle for supplying surfactant onto the substrate 12.
Chemical solution including a surfactant is dripped onto the center
of the surface of the substrate 12, and the substrate 12 is
rotated, whereby, a surfactant is supplied onto the entire surface
of the substrate 12 by centrifugal force generated by the rotation.
By the supply of the surfactant, the surfactant is coated onto the
substrate surface. Water soluble polymer agents may be also
employed, in the place of the surfactant.
[0036] A polishing surface of the polishing tape 13 is made of, for
example, a thin PET film of about several microns to several
hundreds of microns in thickness. Diamond abrasive or SiC, for
example, is adhered on the polishing surface of the polishing tape
13 by an urethane type adhesive. Abrasives to be adhered onto the
polishing tape 13 are selected according to the kinds of substrates
to be processed and required performances thereof, and for example,
diamond with the particle size of #2000 to #30000 and SiC with the
particle size of #2000 to #20000 may be employed.
[0037] Examples of the surfactant include anion system surfactants:
polycarboxylic acid system (for example, polycarboxylic acid
ammonium), polyacrylic acid system (for example, polyacrylic acid
ammonium), alkyl benzene sulphonate system (for example, potassium
dodecylbenzene sulphonate), cation system surfactants: polyethylene
imine system, quaternary ammonium salt (polydialkyl ammonium
chloride), nonion system surfactants: acetylene diole system,
polyoxyethylene alkyl ether, and polyvinyl pyrrolidone.
[0038] Examples of the water soluble polymer agent include
cellulose systems (methyl cellulose, methyl hydroxyethyl cellulose,
methyl hydroxypropyl cellulose, hydroxyethyl cellulose,
hydroxypropyl cellulose, carboxymethyl cellulose, carboxyethyl
cellulose, carboxymethyl hydroxyethyl cellulose), and chitosan
groups.
[0039] These solutions may be selected appropriately according to
the characteristics of the surface of the substrate to be processed
and the characteristics of particles to become stain sources. As
described later herein, when resist is applied onto the substrate
surface, cellulose system, acetylene diol system, and alkyl benzene
sulfonic acid system are effective for hydrophilic property of
resist, and these may be selected appropriately.
[0040] Next, a substrate processing method by use of the polishing
device having the above configuration will be explained by
reference to FIGS. 2 to 6. Herein, a method is explained in which
deep trenches of a trench capacitor are formed in a surface of a
semiconductor wafer (Si wafer) by an RIE method, and roughness that
occurs on a surface of a circumferential portion (bevel portion and
edge portion) of the wafer at this moment is removed. The trench
capacitor is used in, for example, a DRAM cell.
[0041] First, as shown in FIG. 2, a hard mask composed of laminated
films of an SiO.sub.2 film 22 and an SiN film 23 is formed on an Si
wafer 21. Herein, the thickness of the SiO.sub.2 film 22 is, for
example, 90 nm, and the thickness of the SiN film 23 is, for
example, 200 nm.
[0042] Next, as shown in FIG. 3, with the hard mask as a mask, the
Si wafer 21 is etched by the RIE method, and deep trenches 34 are
formed in the Si wafer 21. For example, the opening diameter of the
deep trenches is 0.25 .mu.m, and the depth thereof is 7 .mu.m. By
the RIE process, thorn-shaped protrusions 25 are formed on a
surface of a circumferential portion of the Si wafer 21.
[0043] In more details, a by-product generated in the etching
adheres to the bevel portion and the edge portion of the Si wafer
21. Then, because this by-product works as an etching mask,
thorn-shaped protrusions are formed on the bevel portion and the
edge portion of the Si wafer 21. In particular, when attempt is
made to form an extremely large deep trench 24 whose opening
diameter is of a sub micron order, and whose aspect ratio is
several tens, the thorn-shaped protrusions 25 are apt to occur at
the bevel portion and the edge portion due to its process
conditions. In the present embodiment, the thorn-shaped protrusions
25 are removed by using the polishing device mentioned above.
[0044] Before polishing, for the purpose of protection of the
substrate surface, a resist 26 is applied onto the Si wafer 21
except the bevel portion and the edge portion as shown in FIG. 4.
The material of the resist 26 is, for example, an aromatic azido
compound, or an aromatic diazido compound, and formation of the
resist 26 makes the substrate surface hydrophobic. The resist 26
also has a function of preventing polishing particles and Si
particles generated by polishing, as described later, from entering
the trenches 24.
[0045] The structure shown in FIG. 4 is used as the substrate 12 to
be processed, and the substrate 12 is held on the substrate holding
portion 11 of the polishing device shown in FIG. 1. Then, the
substrate holding portion 11 to which the substrate 12 is held is
rotated, and a surfactant is dripped from the surfactant supply
nozzle 16 onto the center of the substrate surface. Alternatively,
after the surfactant is dripped from the surfactant supply nozzle
16 onto the center of the substrate surface, the substrate holding
portion 11 having held thereon the substrate 12 is rotated. In this
manner, the surfactant is supplied onto the entire surface of the
substrate by centrifugal generated by the rotation of the substrate
holding portion 11, and coating of surfactant is applied onto the
substrate surface.
[0046] Next, the polishing head 14 is moved to the sidewall of the
substrate 12, and the polishing head 14 is pressed onto the
substrate 12 such that the bevel. portion of the substrate 12 are
pinched by the polishing tape 13 of the polishing head 14 from the
above and the below by deflection of the polishing tape 13. By this
pinching process, the area of several millimeters at the edge
portion of the device formation surface may be made into a
polishing area. Then, by rotating the substrate holding portion 11,
the substrate 12 is rotated, and the bevel portion and the edge
portion of the substrate 12 and the polishing tape 13 of the
polishing head 14 are slid, thereby polishing the bevel portion and
the edge portion of the substrate 12.
[0047] At this polishing process, pure water is continuously
dripped from the pure water supply nozzle 15 onto the center of the
surface of the substrate 12, and the pure water is guided toward
the outer side on the surface of the substrate 12 by centrifugal
force of the rotation of the substrate holding portion 11, and
guided to the contact portion between the circumferential portion
of the substrate 12 and the polishing tape 13. In the case where it
is supposed that the coating effect of the surfactant is weakened
by the pure water supply to the substrate surface, the surfactant
may be dripped from the surfactant supply nozzle 16 during the
polishing process. In this case, the surfactant may be dripped
continuously, or intermittently at a certain interval.
[0048] Through the above polishing process, as shown in FIG. 5,
there is no protrusion on the circumferential portion of the Si
wafer 21, and a flat surface is obtained.
[0049] After the polishing ends, a physical cleaning process such
as brush scrubbing or ultrasonic cleaning is carried out to the
substrate surface to remove particles and other extraneous matters
adhering to the surface of the resist 26. In the case of the
present embodiment, because the substrate surface is protected by
the resist 26, the particles and other extraneous matters adhering
to the surface of the resist 36 may be removed by use of chemical
etching in the place of the physical cleaning process. Thereafter,
as shown in FIG. 6, the resist 26 is removed by an ashing process
using oxygen gas or the like.
[0050] FIG. 7 is a graph showing decreasing effects of residual
particles on a substrate by use of a surfactant in polishing the
bevel portion.
[0051] In the case where the bevel portion were polished without
supplying the surfactant, the number of particles residual on the
resist surface after polishing was confirmed to be tens of
thousands as shown by reference character A in FIG. 7. On the
contrary, in the case where the bevel portion were polished after a
coating process by the surfactant as explained in the present
embodiment, the number of particles residual on the resist surface
after polishing was decreased to below 1000, as shown by reference
character B in FIG. 7. Further, as explained in the embodiment, by
adding a physical cleaning process after the polishing process, the
number of particles residual on the resist surface after polishing
was greatly decreased to around 10, as shown reference character by
C in FIG. 7. According to the conventional method, even when a
physical cleaning process was added after polishing process, the
number of particles was hardly decreased.
[0052] According to the embodiment, with respect to an Si wafer 21
on which deep trenches of a trench capacitor are formed by a RIE
method, as a previous step of process of polishing the
circumferential portion thereof, the surfactant is supplied on the
substrate surface and coating thereof is carried out, thereby, it
is possible to prevent particles from firmly adhering onto the
substrate surface during polishing process. As a consequence,
particles may be easily removed from the substrate surface by a
physical cleaning process after polishing process, and accordingly,
it is possible to make the substrate surface free of particles, or
nearly free thereof. Therefore, it is possible to improve the
reliability and yield of a semiconductor device to be
manufactured.
[0053] Further, since the bevel portion and the edge portion of the
wafer 21 after removal of the thorn-shaped protrusions 25 become
flat surfaces, the problems with the CDE method mentioned
previously are solved. Namely, when the CDE method is employed so
as to remove the thorn-shaped protrusions 25 on the bevel portion
and the edge portion, concaves and convexes according to the uneven
height of the thorn-shaped protrusions are formed on the bevel
portion and the edge portion, and dust easily collects in thee
concaves and convexes in machine processing such as CMP to be
carried out in later processes, which becomes a problem. However,
according to the present embodiment, since the concaves and
convexes are not formed, the prior art problem is solved.
[0054] Furthermore, the polishing device used in the embodiment is
extremely simple, and therefore, it is possible to make the cost of
the device itself low. Further, since the materials to be used are
only pure water and surfactant, it is possible to reduce the
running costs significantly. As explained above, according to the
embodiment, a great advantage can be attained in the viewpoint of
cost reduction.
[0055] Moreover, if films that adhere to the circumferential
portion and the like of the substrate to become stain sources are
removed by a polishing process using a polishing tape, the above
removal may be realized in a single process. Therefore, it is
possible to remove the films that become stain sources in a shorter
time in comparison with the conventional wet etching method, and
also to improve the throughput.
Modified Embodiments
[0056] The present invention is not limited to the embodiment
described above. In the above embodiment, the substrate
circumferential portion is polished by sliding action of the
polishing tape attached to the polishing head. However, a polishing
member such as a fixed-abrasive pad formed by fixing an abrasive
with a binder may be used, instead. Further, it is possible to
employ a polishing cloth as a polishing member in the place of the
polishing tape and to supply a polishing solution containing
polishing abrasives in place of pure water, to polish the substrate
circumferential portion. Moreover, the present invention is
applicable to polish a cutout portion, i.e., a so-called notch
portion, formed at a portion of the wafer circumferential portion
as an alignment mark for use in aligning a mask and the wafer and
also as a crystal orientation determining mark to determine a
crystal orientation on the main surface of the wafer.
[0057] In the embodiment, the substrate holding portion having held
thereon the substrate to be processed is rotated. However, the
polishing head may be rotated, instead. Further, the substrate and
the polishing head may be rotated in respectively reverse
directions. Furthermore, the movement of the substrate holding
portion and the polishing head is not necessarily limited to the
rotational movement. Other movement may be employed so long as it
is a plane movement. Still further, the number of the polishing
heads is not limited to one. A plurality of polishing heads may be
arranged along the circumferential portion of the substrate to be
processed.
[0058] Furthermore, in the above embodiment, pure water or chemical
solution such as polishing solution is dripped onto the center of
the surface of the rotating substrate 12, whereby it is supplied to
the contact portion between the substrate circumferential portion
and the polishing member by centrifugal force. However, the pure
water or the chemical solution such as the polishing solution may
be directly supplied to the contact portion between the substrate
circumferential portion and the polishing member. Specifically,
pure water or chemical solution may be supplied onto the
circumferential portion of the rotating substrate at upstream side
in the sliding direction of the contact portion between the
substrate circumferential portion and the polishing member.
[0059] In addition, the polishing head is made to be flexible,
whereby it is possible to remove unevenness of pressure on the
contact surface and make the polishing amount uniform. By giving
flexibility to the polishing head, the polishing member may be
contacted not only onto the bevel portion but also onto the edge
portion, and therefore, the entire wafer circumferential portion
can be polished uniformly. Furthermore, when the polishing head is
inclined from the vertical surface, it is possible to sufficiently
polish not only the bevel portion but also the edge portion of the
wafer.
[0060] Further, in the above embodiments, an example in which the
Si wafer is used as the substrate has been explained, however, in
place thereof, semiconductor wafers such as an SOI wafer and an
SiGe wafer may be employed. Further, an Si wafer whose device
formation surface is formed of SiGe may be employed.
[0061] Furthermore, in the above embodiment, a resist is employed
for the purpose of protection of the substrate surface. However,
other organic films than a resist may be employed. In addition,
after completion of polishing, it is not necessary to remove all of
the organic film, but only part of the stained surface thereof may
be removed, and the remaining portion of the organic film may be
used as a protective film in the later processes.
[0062] FIG. 8 is a flow chart of processing a substrate with
instructions from a control section, i.e., a computer, which can
read and execute a program of processing a substrate readable and
executable by a computer, comprising applying a surfactant or a
water soluble polymer agent onto a surface of a substrate to be
processed, and sliding a circumferential portion of the substrate
and a polishing member against each other to polish the
circumferential portion of the substrate.
[0063] Specifically, as shown in the flow chart in FIG. 8, the
control section issues an instruction for opening a surfactant
supply valve to supply a surfactant onto a surface of a substrate
to be processed. In accordance with the issuance of the surfactant
supply instruction, the surfactant is supplied and coated onto the
surface of the substrate (step S11). The flow rate and the supply
time duration are controlled by the control section, and the
control section issues a surfactant supply end instruction for
closing the surfactant supply valve to end the supply of the
surfactant onto the surface of the substrate. In accordance with
the issuance of the surfactant supply end instruction, the supply
of the surfactant onto the surface of the substrate ends (step
S12). After that, the control section issues a slide instruction
including the rotation of the substrate, the supply of processing
pressure, the supply of the surfactant, the supply of pure water,
etc. In accordance with the issuance of the slide instruction, a
circumferential portion of the substrate and a polishing member are
slide against each other, and polishing of the circumferential
portion of the substrate starts (step S13). During the polishing
(step S14), the number of rotations of the substrate, the
processing pressure, the flow rate of the surfactant, the flow rate
of pure water, the processing time, etc. are controlled by the
control section, and the control section issues a polishing end
instruction including end of the rotation of the substrate, end of
the supply of processing pressure, end of the supply of the
surfactant, end of the supply of pure water, etc. In accordance
with the issuance of the polishing end instruction, polishing of
the substrate ends (step S15). The surfactant may be replaced with
a water soluble polymer agent. The pure water may be replaced with
a chemical solution.
[0064] In the flow chart shown in FIG. 8, the surfactant is
supplied and coated onto the surface of the substrate only before
polishing the circumferential portion of the substrate. FIG. 9
shows a flow chart in which a surfactant is applied onto a surface
of a substrate from before polishing the circumferential portion of
the substrate until the end of the polishing. Specifically, the
control section issues an instruction for opening a surfactant
supply valve to supply a surfactant onto a surface of a substrate
to be processed. In accordance with the issuance of the surfactant
supply instruction, the surfactant is supplied and coated onto the
surface of the substrate (step S21). The flow rate and the supply
time duration of the surfactant are controlled by the control
section, and the supply of the surfactant continues. Under this
state, the control section issues a slide instruction including the
rotation of the substrate, the supply of processing pressure, the
supply of the surfactant, the supply of pure water, etc. In
accordance with the issuance of the slide instruction, a
circumferential portion of the substrate and a polishing member are
slide against each other, and polish of the circumferential portion
of the substrate starts (step S22). During the polishing (step
S23), the number of rotations of the substrate, the processing
pressure, the flow rate of the surfactant, the flow rate of pure
water, the processing time, etc. are controlled by the control
section, and the control section issues a polishing end instruction
including end of the rotation of the substrate, end of the supply
of processing pressure, end of the supply of pure water, etc. In
accordance with the issuance of the polishing end instruction,
polishing of the substrate ends (step 24). After the end of the
polishing, the control section issues a surfactant supply end
instruction for closing the surfactant supply valve to end the
supply of the surfactant onto the surface of the substrate. In
accordance with the issuance of the surfactant supply end
instruction, the supply of the surfactant onto the surface of the
substrate ends (step S25). The surfactant may be replaced with a
water soluble polymer agent. The pure water may be replaced with a
chemical solution.
[0065] FIG. 10 is a flow chart of cleaning a substrate carried out
following the process flows shown in FIGS. 8 and 9.
[0066] As shown in FIG. 10, after polishing the wafer (FIGS. 8 and
9), the control section issues a cleaning start instruction. In
accordance with the cleaning start instruction, a wafer cleaning
starts (step S31). During the wafer cleaning (step S32), cleaning
parameters are controlled by the control section. The control
section issues a cleaning end instruction. In accordance with the
cleaning end instruction, the wafer cleaning ends (step S33).
[0067] According to the above embodiment, in polishing a
circumferential portion of a substrate to be processed, a
surfactant or a water soluble polymer agent is supplied onto the
substrate surface in advance, thereby coating of the surfactant or
the water soluble polymer agent is carried out onto the substrate
surface, this makes it possible to prevent particles from firmly
adhering onto the substrate surface. Accordingly, particles may be
easily removed from the substrate surface by a physical cleaning
process or the like after polishing process, so that the substrate
surface is made free of particles, or nearly free thereof.
Therefore, it is possible to improve the reliability and yield of a
semiconductor device to be manufactured.
[0068] Additional advantages and modifications will readily occur
to those skilled in the art. Therefore, the invention in its
broader aspects is not limited to the specific details and
representative embodiments shown and described herein. Accordingly,
various modifications may be made without departing from the spirit
or scope of the general inventive concept as defined by the
appended claims and their equivalents.
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