U.S. patent application number 11/531856 was filed with the patent office on 2010-11-18 for processing apparatus and method.
Invention is credited to Kazuyuki Kasumi, Eigo Kawakami, Takashi Nakamura, Hirohisa Ota, Toshinobu Tokita.
Application Number | 20100289190 11/531856 |
Document ID | / |
Family ID | 37941059 |
Filed Date | 2010-11-18 |
United States Patent
Application |
20100289190 |
Kind Code |
A1 |
Kawakami; Eigo ; et
al. |
November 18, 2010 |
PROCESSING APPARATUS AND METHOD
Abstract
A processing method for transferring a relief pattern of a mold
to a resist includes the steps of compressing the mold having the
relief pattern against the resist on a substrate, irradiating an
exposure light onto the resist through the mold, vibrating the mold
and the substrate relative to each other during the irradiating
step, and releasing the mold from the resist.
Inventors: |
Kawakami; Eigo;
(Utsunomiya-shi, JP) ; Ota; Hirohisa;
(Kawagoe-shi, JP) ; Nakamura; Takashi; (Tokyo,
JP) ; Kasumi; Kazuyuki; (Utsunomiya-shi, JP) ;
Tokita; Toshinobu; (Yokohama-shi, JP) |
Correspondence
Address: |
ROSSI, KIMMS & McDOWELL LLP.
20609 Gordon Park Square, Suite 150
Ashburn
VA
20147
US
|
Family ID: |
37941059 |
Appl. No.: |
11/531856 |
Filed: |
September 14, 2006 |
Current U.S.
Class: |
264/496 ; 216/44;
264/406; 425/174.4 |
Current CPC
Class: |
G03F 7/0002 20130101;
B29C 2043/025 20130101; B82Y 40/00 20130101; B29C 43/021 20130101;
B82Y 10/00 20130101 |
Class at
Publication: |
264/496 ;
264/406; 425/174.4; 216/44 |
International
Class: |
B29C 35/08 20060101
B29C035/08; G01B 15/00 20060101 G01B015/00; B28B 1/29 20060101
B28B001/29 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 14, 2005 |
JP |
2005-266195 |
Claims
1. A processing method for transferring a relief pattern of a mold
to a resist on a substrate, said processing method comprising: a
compressing step of compressing the mold against the resist; a
curing step of curing the resist by irradiating an exposure light
onto the resist through the mold; a vibrating step of applying a
vibration to at least one of the mold or the substrate while
irradiating the exposure light; and a releasing step of releasing
the mold from the resist.
2. A processing method according to claim 1, wherein said vibrating
step includes adjusting at least one of a frequency or an amplitude
of the vibration based on at least one of a characteristic of the
resist or a shape of the relief pattern.
3. A processing method according to claim 1, further comprising: a
compression determining step of determining whether a compression
state in said compressing step is a predetermined state, wherein
said vibrating step starts the application of the vibration when
said compression determining step determines that the compression
state is the predetermined state.
4. A processing method according to claim 3, wherein the
compression state includes at least one of a compression force
between the mold and the resist or an interval between the mold and
the substrate.
5. A processing method according to claim 1, further comprising: an
exposure determining step of determining whether an exposure dose
of the exposure light is a predetermined amount, wherein said
vibrating step starts the application of the vibration when said
exposure determining step determines that the exposure dose is the
predetermined amount.
6. A processing method according to claim 1, the vibration in said
vibrating step includes two or more types of vibrations having
different frequencies or amplitudes or both.
7. A processing apparatus for compressing a mold having a relief
pattern against a resist on a substrate, and for irradiating an
exposure light onto the resist through the mold, thereby
transferring the relief pattern to the resist, said processing
apparatus comprising: a magnification corrector for changing a
magnification of the pattern by an external force applied to the
mold; and a controller for controlling said magnification so as to
vibrate the mold when determining that a compression state between
the mold and the resist is a predetermined state or when a dose of
the light is a predetermined amount.
8. A device manufacturing method comprising the steps of:
transferring a pattern onto a resist of a substrate using a
processing apparatus according to claim 7; and etching the
substrate.
9. A processing method according to claim 1, further comprising: a
magnification adjusting step of adjusting a magnification of the
relief pattern, wherein members used in said the magnification
adjusting step are used in said vibrating step.
10. A processing method according to claim 1, further comprising an
impact applying step of applying an impact to at least one of the
mold or the substrate.
11. A processing method according to claim 1, wherein the vibrating
step starts the application of the vibration before the curing step
starts irradiating the exposure light, and ends the application of
the vibration after the curing step ends irradiating the exposure
light.
12. A processing method for transferring a relief pattern of a mold
to a resin on a substrate, the processing method comprising: a
compressing step of compressing the mold against the resin; a
curing step of curing the resin; a vibrating step of applying a
vibration to at least one of the mold or the substrate; and a
releasing step of releasing the mold from the resin, wherein the
vibrating step is starts the application of the vibration before
the curing step starts curing the resin.
13. A processing method according to claim 12, wherein the
vibrating step ends the application of the vibration after the
curing step ends curing the resin.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a processing apparatus and
method, and more particularly to a processing apparatus and method
for transferring a pattern of a mold as an original to a plate,
such as a wafer. The present invention is particularly suitable for
a processing apparatus that utilizes the nanoimprint technology as
fine processing to manufacture a semiconductor, a Micro
Electro-Mechanical Systems ("MEMS"), etc.
[0002] The nanoimprint lithography has already been known as one
alternative technology to the photolithography that uses the
ultraviolet ("UV") light, X-rays and electron beams to form a fine
pattern for a semiconductor device. The nanoimprint lithography is
a technology that transfers a pattern to a resist by pressing a
model or mold having a fine pattern against a substrate, such as a
wafer, to which a resinous material or the resist is applied.
[0003] The nanoimprint has several types, and one method is a
photo-curing method. See, for example, M. Colburn et al., "Step and
Flash Imprint Lithography: A New Approach to High-Resolution
Patterning", Proceedings of the SPIE's 24th International Symposium
on Microlithography: Emerging Lithographic Technologies III, Santa
Clara, Calif., Vol. 3676, Part One, pp. 379-389, March 1999. The
photo-curing method is a method of exposing and curing the UV
curable resin as the resist while pressing a transparent mold
against it, and of releasing the mold.
[0004] FIG. 15 is a sectional view showing a relationship among a
conventional mold M, a mold chuck 11, and a mold chuck stage 12.
The mold M has a relief pattern P on its surface, and is fixed onto
the mold chuck 11 by a mechanical member (not shown). 11P denote
plural positioning pins for restricting a position of the mold M on
the mold chuck 11 in installing the mold M on the mold chuck 11.
The mold chuck 11 is also placed on the mold chuck stage 12 by
another mechanical member (not shown). The mold chuck 11 has an
opening 11H and the mold chuck stage 12 has an opening 12H, and
these openings 11H and 12H allow the UV light emitted from a light
source (not shown) to pass through the mold M. Plural load sensors
(not shown) as force detectors are attached to the mold chuck 11 or
the mold chuck stage 12.
[0005] The mold M is pressed against the resist (not shown) via the
mold chuck stage 12 and the mold chuck 11. During pressing, in
accordance with the output of the load sensor, the mold chuck stage
12 controls an inclination of the mold chuck 11 and a servomotor
(not shown) controls a compression state of the mold M. Thereafter,
the UV light is irradiated onto the mold M via the openings 11H and
12H.
[0006] One proposed method assists release by utilizing the
ultrasonic vibration in a pattern's depth direction during release.
See, SCIVAX Corporation, 03. Imprint Technology, Sep. 7, 2005.
[0007] Other prior art include Japanese Patent Applications,
Publication Nos. 2004-288811 and 2003-7597, and Japanese Patent No.
3,450,631.
[0008] FIG. 16 is a sectional view showing a compression state of
the mold M having the transfer pattern P against a resist R on a
wafer W. A principal releasing force after photo-curing is a force
for releasing a perpendicular surface PW of the transfer patter P
from a resist contact surface in parallel rather than a force for
perpendicularly releasing horizontal planes of a concave PB, a
convex PT, and a horizontal part PS of the transfer pattern P from
the resist contact surfaces. One typical method of reducing the
releasing force is a method of applying the release agent to the
mold, but the durability of the release agent weakens as the
release times increases, and the force necessary for the release
disadvantageously increases as the release times increases.
[0009] SCIVAX Corporation, 03. Imprint Technology, Sep. 7, 2005,
teaches to apply the ultrasonic vibration to the mold during
release, but is silent about a detailed pressure relationship
between the mold and the resist in applying the vibration. Japanese
Patent Application, Publication No. 2004-288811 teaches to apply
the ultrasonic vibration to the mold during transferring so as to
lower the molten resin viscosity through the ultrasonic vibration,
to reduce the compression force, and to shorten the transfer time,
rather than facilitating the release. See, for example, Japanese
Patent Application, Publication No. 2004-288811, paragraph nos.
0006 and 0007. After all, the release of the mold requires
experience and skill, a long time period and/or a large force. A
long release time period lowers the throughput of the processing
apparatus, and a large release force needs a bulk releasing force
generator, causing a large size of the entire apparatus or an
increased cost.
BRIEF SUMMARY OF THE INVENTION
[0010] The present invention is directed to a processing apparatus
and method that contributes to an improvement of the throughput and
a miniaturization of the apparatus.
[0011] A processing method according to one aspect of the present
invention for transferring a relief pattern of a mold to a resist
includes the steps of compressing the mold having the relief
pattern against the resist on a substrate, irradiating an exposure
light onto the resist through the mold, vibrating the mold and the
substrate relative to each other during the irradiating step, and
releasing the mold from the resist.
[0012] A processing apparatus according to another aspect of the
present invention for compressing a mold having a relief pattern
against a resist on a substrate, and for irradiating an exposure
light onto the resist through the mold, thereby transferring the
relief pattern to the resist includes a magnification corrector for
changing a magnification of the pattern by an external force
applied to the mold, and a controller for controlling the
magnification so as to vibrate the mold when determining that a
compression state between the mold and the resist is a
predetermined state or when a dose of the light is a predetermined
amount.
[0013] A device manufacturing method according to another aspect of
the present invention includes the steps of transferring a pattern
onto a resist of a substrate using the above processing apparatus,
and etching the substrate. Claims for a device fabricating method
for performing operations similar to that of the above exposure
apparatus cover devices as intermediate and final products. Such
devices include semiconductor chips like an LSI and VLSI, CCDs,
LCDs, magnetic sensors, thin film magnetic heads, and the like.
[0014] Other objects and features of the present invention will
become readily apparent from the following description of the
preferred embodiments with reference to accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a schematic sectional view of a processing
apparatus or a nanoimprint apparatus according to a first
embodiment of the present invention.
[0016] FIG. 2 is a schematic sectional view around a mold chuck of
the processing apparatus shown in FIG. 1.
[0017] FIG. 3 is a flowchart for explaining an operation of the
processing apparatus shown in FIG. 1.
[0018] FIG. 4 is a flowchart for explaining another operation of
the processing apparatus shown in FIG. 1.
[0019] FIG. 5 is a flowchart for explaining still another operation
of the processing apparatus shown in FIG. 1.
[0020] FIG. 6 is a schematic sectional view around the mold chuck
as a variation of a vibrator mechanism shown in FIG. 2.
[0021] FIG. 7 is a flowchart for explaining an operation of the
processing apparatus having the vibrator mechanism shown in FIG.
6.
[0022] FIG. 8 is a schematic sectional view around the mold chuck
as another variation of the vibrator mechanism shown in FIG. 2.
[0023] FIG. 9 is a schematic sectional view around the mold chuck
as still another variation of the vibrator mechanism shown in FIG.
2.
[0024] FIG. 10A is a schematic plane view of the mold chuck shown
in FIG. 9, and FIG. 10B is a schematic plane view of the mold.
[0025] FIG. 11 is a schematic sectional view around the mold chuck
showing still another variation of the vibrator mechanism shown in
FIG. 2.
[0026] FIG. 12 is a flowchart for explaining an operation of the
processing apparatus having the vibrator mechanism shown in FIG.
6.
[0027] FIG. 13 is a flowchart for explaining a manufacturing method
that uses the processing apparatus shown in FIG. 1 to manufacture a
device, such as a semiconductor chip, e.g., an IC and an LSI, an
LCD, and a CCD.
[0028] FIG. 14 is a flowchart of a detailed step 4 shown in FIG.
13.
[0029] FIG. 15 is a sectional view around the conventional mold
chuck.
[0030] FIG. 16 is a sectional view for explaining a release between
the conventional mold and the resist.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] Referring now to the accompanying drawings, a description
will be given of a nanoimprint apparatus or processing apparatus
100 that uses a photo-curing method according to one aspect of the
present invention. Here, FIG. 1 is a schematic sectional view of
the nanoimprint apparatus 100.
[0032] The nanoimprint apparatus 100 includes a compression
adjuster, an interval measuring part, a light-quantity measuring
part, a light irradiator 110, a mold M, an interferometer 120, a
mold driver 130, a vibrator mechanism, a wafer (substrate) W, a
wafer driver 160, a mold feeder, a resist supplier, and another
mechanism.
[0033] The compression adjuster includes a controller 102, a load
sensor 104, and a memory 106. The controller 102 is attached to a
body (not shown) of the apparatus 100. The load sensor 104 is
attached to the mold chuck stage 138 or mold chuck 140, which will
be described later. The memory 106 stores a value of a
predetermined compression force. The controller 102 determines
whether the compression force from the mold M to the wafer W,
detected by the load sensor 104, is the predetermined value stored
in the memory 106. The controller 102 serves not only as a
controller of the compression adjuster, but also as a controller of
each component in the apparatus 100, as described later.
[0034] The interval measuring part includes the controller 102, the
memory 106, and a distance-measuring part 107. The memory 106
stores a value of a predetermined interval. The distance-measuring
part 107 measures a distance between the mold M and the wafer W.
The distance-measuring part 107 is provided to a mold chuck body
142 in FIG. 1, but may be provided to a wafer chuck 162. The
controller 102 determines whether the distance between the mold M
and the wafer W, detected by the distance-measuring part 107, is
the predetermined value stored in the memory 106.
[0035] The light-quantity measuring part includes the controller
102, the memory 106, and a light quantity sensor 108. The memory
106 stores a value of a predetermined light intensity. The light
quantity sensor 108 measure the light intensity irradiated onto the
wafer W. The light quantity sensor 108 is provided to the mold
chuck body 142 in FIG. 1, but may be provided to the wafer chuck
162. The controller 102 determines whether the light intensity
between the mold M and the wafer W, detected by the light quantity
sensor 108, is the predetermined value stored in the memory
106.
[0036] The light irradiating part 110 irradiates, through the mold
M, the UV light and for curing a photo-curing resin or the resist
(not shown) applied onto the wafer W, and includes alight source
part 112, and an illumination optical system 114. The light source
part 112 is controlled by the controller 102, and includes a
halogen lamp that generates the UV light, such as i-line and
g-line, etc. The illumination optical system 114 includes a lens
and an aperture, and shapes the illumination light used to expose
and cure the resist. The illumination optical system 114 is shown
as, but not limited to, a collimator lens (and beam splitters 123
and 124) in FIG. 1. For example, the illumination optical system
may include an optical integrator to uniformly illuminate the mold
M, if necessary.
[0037] The mold M has a pattern P to be transferred to the wafer W,
and is made of a transparent material to transmit the UV light so
as to cure the resist.
[0038] The mold driver 130 includes an imprint mechanism that
serves as a driver used to press the mold M in the lower direction
and to release the mold M in the upper direction in FIG. 1, and the
mold chuck 140 that holds the mold M on the apparatus 100.
[0039] The imprint mechanism provides, in addition to a
longitudinal movement, an orientation changing mechanism and
controls the orientation and alignment in the rotational direction
for an adhesion between the mold transfer surface and the wafer W.
The imprint mechanism includes a guide plate 132, a pair of guide
bars 134, a pair of linear actuators 136, and a mold chuck stage
138. One end of each guide bar 134 is fixed onto the guide plate
132 and perforates the top plate 194. The other end of each guide
bar 134 is fixed onto the mold chuck stage 138. The linear actuator
136 is controlled by the controller 102, and includes an air
cylinder or linear motor. The linear actuator 136 drives the guide
bar 134 in the z direction in FIG. 1. The mold chuck stage 138 has
a correction function of a position in the .theta. direction (or a
rotating direction around the z-axis), and a tilt function to
correct an inclination of the mold M. The mold chuck stage 138 has
a perforation hole or opening 139, and the mold chuck 140 has
perforation holes or openings 143 and 145. The lights from the
light source parts 112 and 121 pass through these openings 139, 143
and 145.
[0040] FIG. 2 shows a sectional view around the mold chuck 140,
which includes positioning pins 141 and a body 142.
[0041] This embodiment provides a piezoelectric element 144 as a
vibrator mechanism to the mold chuck 140.
[0042] The mold M is fixed onto the mold chuck body 142 via plural
positioning pins 141. These positioning pins 141 restrict a
position of the mold M on the body 142 in attaching the mold onto
the body 142.
[0043] The vibrator mechanism vibrates the mold M and the resist R
of the wafer W relative to each other, i.e., at least one of them
relative to the other, and facilitates a subsequent release between
the mold M and the wafer W. The vibration applied by the vibrator
mechanism may be a steady vibration or an impact. Preferably, the
applied vibration has a frequency and amplitude set in accordance
with the shape of the pattern P and the characteristic of the
resist R. For example, the amplitude is made smaller and/or the
oscillation frequency is made higher for a resist having a low
viscosity and a high curing speed (or a high UV sensitivity) or a
relief pattern having a small pitch. The vibrator mechanism
preferably changes the oscillation frequency and/or amplitude
during vibrations, or applies two or more types of vibrations
having different frequencies and/or amplitudes. This is because the
suitable releasing vibration depends upon a frequency and amplitude
due to the pattern P's density. An arbitrary timing after the
irradiation of the UV light starts and before the irradiation of
the UV light ends may be used to apply a relative steady vibration
to the mold and wafer. Preferably, the steady vibration is applied
not just after the UV irradiation starts, but after 30% or more
preferably 50% of the overall irradiation time period elapses.
[0044] The timing of applying the vibration is important. After the
vibration starts after the transfer ends, as disclosed in SCIVAX
Corporation, 03. Imprint technology, the adhesion between the mold
and the resist becomes strong and the releasing force is likely to
increase. On the other hand, Japanese Patent Application,
Publication No. 2004-288811 lowers the molten viscosity by applying
the ultrasonic vibration to the resin for the reduced compression
force and the shortened transfer time period, rather than easy
releasing. For the reduced compression force, the ultrasonic
vibration is applied before the compression but this would
strengthen the adhesion between the mold and the resist in
releasing, and the releasing force is likely to increase.
Accordingly, some embodiments of the present invention apply the
vibration while the light for exposing the resist R is irradiated
onto the resist R. The vibration starts, for example, based on the
compression state between the mold M and the resist R and whether
the exposure light dose reaches the predetermined amount.
[0045] The piezoelectric element 144 of this embodiment forms one
illustrative vibrator mechanism for vibrating the mold M, is
integrated with the mold chuck body 142 between the mold chuck body
142 and the mold chuck stage 138, and vibrates the mold M. The
piezoelectric element 144 has the opening 145 at the center, and
vibrates in the thickness direction or the longitudinal direction
of the paper plane. As described later with reference to FIG. 6,
the vibrator mechanism is not limited to the piezoelectric element
144.
[0046] The interferometer 120 detects the compression state of the
mold N against the wafer W, and includes the illumination light
source 121, a collimator lens 122, beam splitters 123 and 124, and
an imaging system 125, the controller 102, and the memory 106. The
illumination light source 121 projects the light having a different
wavelength from that of the light source part 112, and can also
project a monochromatic light when switched. The collimator lens
122 converts the incident light into the parallel light. The beam
splitter 123 is arranged in the optical path of the light source
part 121, and deflects the projected light from the illumination
light source 121 to the mold M. The beam splitter 124 is similarly
arranged in the optical path of the light source part 121, and
deflects the reflected light from the mold M to the imaging system
125. The imaging system 125 has, for example, a CCD. The memory 106
stores information used to recognize the compression state, and the
controller 102 determines whether the compression state observed by
the interferometer 120 satisfies the predetermined state stored in
the memory 106.
[0047] The wafer W is a plate to which the pattern of the mold M is
transferred, and a semiconductor IC circuit is formed through the
subsequent processes, and similar to that used in the conventional
semiconductor process.
[0048] The wafer driver 160 includes a wafer chuck 162, a
fine-adjustment stage 163, an XY stage 164, a reference mirror 165,
and a laser interferometer 166. The wafer chuck 162 holds the wafer
W. The fine-adjustment stage 163 is controlled by the controller
102, and has a correction function of a position of the .theta.
direction (or the rotating direction around the z-axis), an
adjustment function of a z position of the wafer W, and a tilt
function to correct an inclination of the wafer W. The XY stage 164
is controlled by the controller 102, and is provided so as to
position the wafer W in place. The entire surface of the wafer W is
transferable by the wafer driver 160, and an overlay among fine
patterns is available due to the highly precise positioning and the
orientation adjusting mechanism of the surface of the wafer W. The
reference mirror 165 is attached to the fine-adjustment stage 163
in the x and y directions (although the y direction is not shown),
and reflects the light from the laser interferometer 166. The
reference mirror 165 and the laser interferometer 166 serve to
measure a position of the fine-adjustment stage 163. The laser
interferometer 166 is controlled by the controller 102.
[0049] The mold feeder includes the mold feeding robot 180. The
robot 180 holds and feeds the mold M using a hand 182 through a
vacuum absorption.
[0050] The resist supplier includes a tank (not shown) for storing
the resist before UV irradiation or curing, a nozzle 185 that is
connected to the tank and drops the resist onto the wafer W's
surface, and a valve (not shown) that switches between dropping and
stopping of the resist from the nozzle 185. It is preferable to
control the resist supply amount. For example, in the supply amount
control, the opposing area between the mold M and the wafer W is
calculated from the coordinate position of the XY stage 164, and
the volume is calculated as a necessary supply amount by
multiplying the area by the interval between the average height of
the relief of the mold M and the wafer W. This configuration
prevents an unnecessary resist from spilling from the wafer W, and
from contaminating the wafer chuck 162 and the XY stage 164.
[0051] The other mechanism includes a stool 190 on which the XY
stage is placed, plural posts 192 that stand on the stool 190, and
a top plate 194 supported on these posts 192. The stool 190
supports the entire apparatus 100, and forms a reference plane of
the movement of the wafer stage 164. The stool 190 is placed on a
floor via a damper (not shown). The posts 192 support the
components including the light irradiating part 110 to the mold M
above the wafer W.
[0052] Referring now to FIG. 3, a description will be given of the
processing method of the first embodiment that utilizes the
nanoimprint apparatus 100. Here, FIG. 3 is a flowchart for
explaining an operation of the nanoimprint apparatus 100 of this
embodiment.
[0053] In operation, the wafer W to be transferred is placed on the
wafer chuck 162 by the wafer feeding system (not shown). The wafer
chuck 162 vacuum-absorbs and holds the wafer W. The XY stage 164 is
initially driven to move the wafer chuck 162 mounted with the wafer
W, and to position it under the nozzle 185 at a location or shot on
the wafer W on which the pattern is transferred.
[0054] Next, the nozzle 185 drops a proper amount of resist
(photo-curing resin) on a target shot of the wafer W (step 1002).
Next, the wafer W is positioned (step 1004). More specifically,
after the XY stage 164 is driven so that the shot plane is located
opposite to the pattern P of the mold M, the fine-adjustment stage
163 is driven so that a height and inclination in the Z direction
of the wafer chuck 162. The shot surface of the wafer W is aligned
with the reference plane (not shown) of the apparatus 100.
[0055] Next, the imprint mechanism drives the linear actuator 136
and descends the mold chuck 140 and the mold M to the predetermined
position, compressing the mold M against the resist (step 1006).
The controller 102 determines based on the output of the load
sensor 104 whether the compression force is within a predetermined
range (step 1008).
[0056] The controller 102 when determining that the compression
force is not within the predetermined range (step 1008) directs the
mold chuck stage 138 to change the position and inclination in the
z direction of the mold chuck 140 or the fine-adjustment stage 163
to change the position and inclination in the z direction of the
wafer chuck 162, adjusting the compression force of the mold M
(step 1010). Steps 1008 and 1010 are repeated until the
predetermined compression force is obtained.
[0057] On the other hand, the controller 102 when determining that
the compression force of the mold M is proper (step 1008) starts
the vibration of the piezoelectric element 144 in the thickness
direction to minutely vibrate the mold M in the compression
direction or the z direction in FIG. 1 (step 1012). Subsequently,
the light source part 112 irradiates the UV light for a
predetermined time period (step 1014). In that case, the frequency
and amplitude of the fine vibration are changed in accordance with
the resist characteristic and the pattern shape, as described
above. When the UV irradiation ends, the piezoelectric element 144
stops vibrating (step 1016).
[0058] Next, the controller 102 drives the linear actuator 136 to
ascend the mold chuck 140 and release the mold M from the resist on
the wafer W (step 1018). Lastly, the controller 102 drives the XY
stage 164 (step 1020) to move the wafer W so that the next shot is
under the nozzle 185. This procedure is repeated for sequential
transfers (step and repeat). When all transfers end, the wafer W is
fed out and the next wafer W is fed in.
[0059] The resist cures with the low degree of coupling between the
mold pattern's perpendicular plane and the resist by the fine
adjustment of the mold in the compression direction during the UV
irradiation. As a result, the release time period can be made
shorter by reducing the force necessary to release the mold.
[0060] Referring now to FIG. 4, a description will be given of the
processing method of the second embodiment utilizing the
nanoimprint apparatus 100. Here, FIG. 4 is a flowchart for
explaining an operation of the nanoimprint apparatus 100 of this
embodiment. This embodiment is different from the first embodiment
in that the mold starts vibrating before the compression of the
mold against the resist ends.
[0061] Steps 1102 to 1104 are similar to steps 1002 to 1004. Next,
the imprint mechanism drives the linear actuator 136 and starts
descending the mold chuck 140 and the mold M down to the
predetermined position (step 1106). The controller 102 determines
whether the distance between the mold M and the wafer W is the
predetermined value stored in the memory 106 (step 1108), and
allows the descent down to the predetermined value. As a result,
the controller 102 confirms that the mold chuck 140 descends down
to the predetermined position. The controller 102 when determining
that the distance between the mold M and the wafer W is a
predetermined value (step 1108) instructs the imprint mechanism to
stop descending the mold chuck 140 (step 1110).
[0062] Next, the controller 102 instructs the piezoelectric element
144 to start vibrating in the thickness direction, and minutely
vibrates the mold M in the compression direction or the z direction
in FIG. 1 (step 1112). The controller 102 determines based on the
output of the load sensor 104 whether the compression force is
within the predetermined range (step 1114).
[0063] When the controller 102 determines that the compression
force is not within the predetermined range (step 1114), the
controller 102 instructs the mold chuck stage 138 to change the
position and the inclination in the z direction of the mold chuck
140 or the fine-adjustment stage 163 to change the position and
inclination in the z direction of the wafer chuck 162, adjusting
the compression force of the mold M (step 1116). The steps 1114 and
1116 repeat until the predetermined compression force is
acquired.
[0064] The controller 102 when determining that the compression
force is within a predetermined range (step 1114) irradiates the UV
light for the predetermined time period through the light source
part 112 (step 1118). In that case, the frequency and amplitude of
the fine vibration change in accordance with the resist
characteristic and the pattern shape. For example, the amplitude is
made smaller and/or the oscillation frequency is made higher for a
resist having a low viscosity and a high curing speed (or a high UV
sensitivity) or a relief pattern having a small pitch. When the UV
irradiation ends, the piezoelectric element 144 stops vibrating
(step 1120).
[0065] Next, the controller 102 drives the linear actuator 136,
ascends the mold chuck 140, and detaches the mold M from the resist
of the wafer W (step 1122). Lastly, the controller 102 drives the
XY stage 164 (step 1124), and moves the wafer W so that the next
shot is located under the nozzle 185. This procedure is repeated
for sequential transfers (step and repeat). When all transfers end,
the wafer W is fed out and the next wafer W is fed in.
[0066] Thus, this embodiment has the same effect as the first
embodiment when the mold is minutely vibrated before the
compression of the mold ends and before the UV irradiation starts.
In addition, the fine vibration has an effect of preventing the air
mixture and residue in the concave in the mold pattern when the
mold is compressed.
[0067] Referring now to FIG. 5, a description will be given of the
processing method of the third embodiment utilizing the nanoimprint
apparatus 100. Here, FIG. 5 is a flowchart for explaining an
operation of the nanoimprint apparatus 100 of this embodiment. This
embodiment is different from the first embodiment in that the fine
vibration of the mold starts after a predetermined dose of the UV
light is irradiated.
[0068] Steps 1202 to 1210 are similar to steps 1002 to 1010. The
controller 102 when determining that the compression force of the
mold M is proper (step 1208) divides the procedure into two (step
1212). Step 1214 irradiates the UV light for the predetermined time
period through the light source part 112. In parallel, the
controller 102 measures the strength of the UV light through the
light quantity sensor 108, and determines whether the predetermined
dose is illuminated from a product between the light intensity and
the irradiation time period (step 1216). The predetermined dose is
within a range between 0 and a dose necessary to completely cure
the resist, and the processing apparatus's user properly sets in
accordance with the resist characteristic and the pattern shape.
The controller 102 continues the irradiation when the irradiation
dose is not the predetermined dose (step 1216). On the other hand,
the controller 102 when determining that the irradiation dose is
the predetermined dose (step 1216) starts the vibration and
minutely vibrates the mold M in the compression direction or z
direction in FIG. 1 (step 1218). The vibration may start
simultaneous with the start of the UV irradiation or during the UV
irradiation, or after the UV irradiation ends. In that case, the
frequency and amplitude of the fine vibration change in accordance
with the resist characteristic and the pattern shape. For example,
the amplitude is made smaller and/or the oscillation frequency is
made higher for a resist having a low viscosity and a high curing
speed (or a high UV sensitivity) or a relief pattern having a small
pitch. When the UV irradiation ends, the piezoelectric element 144
stops vibrating (step 1222). Next, the controller 102 drives the
linear actuator 136 to ascend the mold chuck 140 and release the
mold M from the resist on the wafer W (step 1224). Lastly, the
controller 102 drives the XY stage 164 (step 1226), and the wafer W
is moved so that the next shot is located under the nozzle 185.
This procedure is repeated for sequential transfers (step and
repeat). When all transfers end, the wafer W is fed out and the
next wafer W is fed in.
[0069] Thus, when the timing at which the fine vibration of the
mold starts is adjusted in accordance with the resist
characteristic and the pattern shape, an interface between the
resist and mold pattern's perpendicular surface can be prevented
from coupling and can be more effectively separated. As a result,
the force necessary to release the mold can be reduced, and the
release time period can be shortened.
[0070] FIG. 6 is a sectional view around the mold chuck showing a
variation of the vibration mechanism shown in FIG. 2. This
embodiment uses an actuator 146 for the vibration mechanism instead
of the piezoelectric element 144. Those elements in FIG. 6 which
are the corresponding elements in FIG. 2 are designated by the same
reference numerals, and a description thereof will be omitted. A
mold chuck 140A houses the actuator 146 instead of the
piezoelectric element 144. The actuator 146 has a movable pin 147,
which projects and collides with the mold chuck stage 138. The
actuator 146 includes an air cylinder and a voice coil motor. The
number of actuators 146 is not limited.
[0071] A closed space for accommodating the actuator 146 is formed
inside the mold chuck 140A, and the movable pin 147 may collide
with the ceiling of the closed space instead of the mold chuck
stage 138. The actuator 146 may be located in a closed space 169 in
the wafer chuck 162 instead of the mold chuck 140B as shown in FIG.
8, and the movable pin 147 may collide with the ceiling of the
closed space 169. Moreover, the fine-adjustment stage 163 may have
the actuator instead of the mold chuck 140A and the wafer chuck
162. When the fine-adjustment stage 163 is quickly moved in the z
direction by a small amount, an impact can be applied to the mold
M.
[0072] FIG. 7 is a flowchart common to operations of the
nanoimprint apparatuses having the vibrator mechanisms shown in
FIGS. 6 and 8. In FIG. 7, the flow up to step 1310 is similar to
the flow up to step 1010 shown in FIG. 3, and step 1312 is similar
to step 1014. Next, the actuator 146 housed in the mold chuck 140A
is activated, and the movable pin 147 hits the rear surface of the
mold chuck 140A or the ceiling of the closed space 169 (step 1314).
The reaction at this time is transmitted as an impact to the mold
M. The release starting point is formed between the cured resist R
and the mold M. Steps 1316 and 1318 are similar to steps 1018 and
1020. Plural combinations of the actuator 146 and the movable pin
147 may be prepared so as to form plural release starting
points.
[0073] Thus, the release starting point can be formed by applying
the impact to the mold before the mold is released but after the UV
light is irradiated, and a smaller force can release the mold from
that starting point. The configuration shown in FIG. 8 does not
require the actuator 146 for each shot because an impact may be
consequently transmitted to the mold.
[0074] FIG. 9 is a sectional view around the mold chuck 140C
showing a variation of the arrangement of the vibrator mechanisms
shown in FIGS. 6 and 8. FIG. 10A is a schematic plane view of the
mold chuck 1400. FIG. 10B is a schematic plane view of the mold M.
The section shown in an A-A' broken line in FIG. 10A corresponds to
FIG. 9. In FIG. 9, the mold chuck 140C that is fixed onto the mold
chuck stage 138 by a mechanical holder is transparent to the UV
light from the light source part 112, such as quartz.
[0075] The mold chuck 140C of this embodiment has an exhaust
passage 150, an O-ring 152, and a pair of alignment marks MC
instead of the positioning pins 141, and two pairs of the actuator
146 and the fixing pin 148 are fixed on the bottom surface.
[0076] The exhaust passage 150 is connected to a vacuum pipe 154,
and the vacuum pipe 154 is connected to a vacuum pump (not shown).
As a result, the mold M is vacuum-absorbed by the mold chuck 140C.
The O-ring 152 has an annular shape that encloses the vicinity of
the mold M, as shown in FIGS. 9 and 10A, and maintains the degree
of vacuum between the mold M and the mold chuck 140C.
[0077] A pair of alignment marks MC are located in place inside the
O-ring 152 where the irradiated UV light does not pass, and the
mold M also has a pair of alignment marks MM in place corresponding
to the alignment marks MC outside the pattern P. The alignment
marks MC and MM are used for an alignment on the xy plane when the
mold feeding robot 180 attaches the mold M to the mold chuck 140C.
The alignment mark is effective when it is difficult to provide a
positioning pin etc. to the optically transparent mold chuck. Since
no positioning pins 141 are necessary, no accidental cracks of the
mold M occur due to a collision between the mold M and the
positioning pin in installing the mold. The alignment mark may be
applied to the above embodiments.
[0078] The actuator 146 is fixed on the bottom surface of the mold
chuck 1400 so that the moving direction of the movable pin 147 is
approximately perpendicular to that in FIGS. 6 and 8. The movable
pin 147 may hit a side surface MS of the mold M. The fixing pin 148
stands vertically to the bottom surface, and is arranged in an
extended moving direction of the movable pin 147 through the mold
M. As shown in FIG. 10A, two pairs of the actuators 146 and the
fixing pins 148 are arranged in the diagonal direction of the
pattern P, and used for the magnification correction of the pattern
P. This assignee discloses, in Japanese Patent Application,
Publication No. 2003-7597, the operation at the magnification
correction time, and a description thereof will be omitted.
[0079] The operational flowchart of the nanoimprint apparatus shown
in FIG. 7 is applicable to the structure shown in FIGS. 9 to 10B.
The impact direction is approximately perpendicular to that in
FIGS. 6 and 8, in which the impact direction is perpendicular to
the mold pattern surface. This embodiment has an impact direction
parallel to the pattern surface. This embodiment uses the
magnification corrector in step 1314 in FIG. 7 in applying the
impact to the mold M. More specifically, the movable pin 147 that
is pressed against the mold M by the actuator 146 is once retreated
to the actuator 146 side and again compressed against the mold M.
This configuration forms a release starting point by applying the
impact to the pre-released mold M.
[0080] Thus, the effects shown in FIGS. 6 to 8 can be obtained by
diverting the magnification corrector of the mold pattern P.
[0081] FIG. 11 is a schematic sectional view around the mold chuck
140D showing still another variation of the vibrator mechanism
shown in FIG. 2. The mold chuck 140D includes both the
piezoelectric element 144 and the actuator 146 for the vibrator
mechanism. The piezoelectric element 144 is located between the
mold chuck 140D and the mold chuck stage 138, and a pair of
actuators 146 are arranged in the body 142D. Those elements in FIG.
11 which are the same as corresponding elements in FIGS. 2 and 6
are designated by the same reference numerals, and a detailed
description will be omitted.
[0082] FIG. 12 is a flowchart of the nanoimprint apparatus having
the mold chuck 140D shown in FIG. 11. In FIG. 12, steps 1402 to
1414 and steps 1418 to 1422 are similar to steps 1002 to 1014 and
steps 1016 to 1020 in FIG. 3. A difference from FIG. 3 is an
addition of step 1416 that applies the impact to the mold M through
the actuator 146 before the fine vibration of the piezoelectric
element 144 stops and after the UV irradiation (step 1414) for a
predetermined time period.
[0083] Thus, the mold is minutely vibrated while the resist is
curing, and an additional impact is applied to a weak coupling
state of an interface between the resist and the mold pattern's
perpendicular surface. As a result, a formation of the release
starting point becomes easy, and the force necessary to release the
mold can significantly reduce.
[0084] Referring now to FIGS. 13 and 14, a description will be
given of an embodiment of a device manufacturing method using the
above processing apparatus. FIG. 13 is a flowchart for explaining
how to fabricate devices (i.e., semiconductor chips such as IC and
LSI, LCDs, CCDs, etc.). Here, a description will be given of the
manufacture of a semiconductor chip as an example. Step 1 (circuit
design) designs a semiconductor device circuit. Step 2 (mold
fabrication) forms a mold that forms a pattern corresponding to a
designed circuit pattern. Step 3 (wafer preparation) manufactures a
wafer using materials such as silicon. Step 4 (wafer process),
which is also referred to as a pretreatment, forms actual circuitry
on the wafer through the nanoimprint technique using the mold and
wafer. Step 5 (assembly), which is also referred to as a
post-treatment, forms into a semiconductor chip the wafer formed in
Step 4 and includes an assembly step (dicing and bonding), a
packaging step (chip sealing), and the like. Step 6 (inspection)
performs various tests for the semiconductor device made in Step 5,
such as a validity test and a durability test. Through these steps,
a semiconductor device is finished and shipped (Step 7).
[0085] FIG. 14 is a detailed flowchart of the wafer process in Step
4. Step 11 (oxidation) oxidizes the wafer's surface Step 12 (CVD)
forms an insulating film on the wafer's surface. Step 13 (electrode
formation) forms electrodes on the wafer by vapor disposition and
the like. Step 14 (ion implantation) implants ions into the wafer.
Step 15 (transfer) presses the mold against the wafer while
applying a photosensitive material to the wafer, and irradiates the
UV light to transfer the circuit pattern onto the wafer. Step 16
(etching) uses reactive ion etching (RIE) to complete the
patterning operation. Step 17 (resist stripping) removes disused
resist after etching. Thus, devices (i.e., semiconductor chips, LCD
devices, photographing devices (such as CCDs, etc.), thin-film
magnetic heads, and the like) are fabricated. These steps are
repeated, and multi-layer circuit patterns are formed on the wafer.
Thus, the device manufacturing method using the nanoimprint
technology of this embodiment, and devices as a resultant product
constitute one aspect of this invention. The present invention
intends to cover devices as intermediate and final products of this
device manufacturing method. Such devices include semiconductor
chips such as LSI, VLSI and the like, CCDs, LCDs, magnetic sensors,
thin film magnetic heads, and the like.
[0086] Further, the present invention is not limited to these
preferred embodiments, and various variations and modifications may
be made without departing from the scope of the present
invention.
[0087] This application claims a foreign priority benefit based on
Japanese Patent Application No. 2005-266195, filed on Sep. 14,
2005, which is hereby incorporated by reference herein in its
entirety as if fully set forth herein.
* * * * *