JP2007173614A - Micro fabricating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a micro fabricating device accurately and simply detecting an inclination and position of the surface of a mold and the surface of a body to be transcribed mutually contacting at the time of imprinting to press the mold to a resist without an inclination of the mold, accurately transcribing without an exfoliation, and falling of the pattern after the hardening of the resist. <P>SOLUTION: The micro fabricating device comprises a detecting means for detecting the inclination and the position of the mold and the body to be transcribed, and a controlling means for controlling the posture of the mold to the body to be transcribed by a signal obtained by the detecting means. The micro fabricating device for impressing and transcribing the pattern formed on the mold 1 to the body 3 to be transcribed detects the inclination and the position of the surface with the mold 1 and the body 3 faced each other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fine processing apparatus using nanoimprinting for controlling the relative position and angle between a wafer and a mold.

  Conventionally, in a microfabrication apparatus using nanoimprint, in order to align the relative position between a wafer and a mold, a method of forming a mold and a mark on a mold substrate and simultaneously observing and referring to the mark on the wafer, or processing a workpiece A method is known in which conditions for processing are determined by pressing an original plate against a predetermined member before performing (see, for example, Patent Documents 1 and 2).

FIG. 14 is a schematic view showing a conventional microfabrication apparatus. FIG. 15 is a schematic view showing a state in which the mold substrate of FIG. 14 is tilted. FIG. 16 is a schematic view showing a state where the mold substrate of FIG. 14 is pressed against the workpiece while being tilted.
As shown in FIGS. 14 to 16, in the microfabrication apparatus disclosed in Patent Document 1, the nanoimprint mold 1 provided with the nanoimprint mold 1 is positioned on the mold substrate 4 and the wafer 3 in order to perform positioning with high accuracy. Reference marks 5 and 6 are formed.
As shown in FIG. 14, alignment is performed by observing and referring to these position reference marks 5 and 6 through light, electrons, ions or X-rays. By aligning the positions of the mold side mark 5 and the wafer side mark 6, the mold 1 and the resist 2 can be aligned on the XY plane. This makes it possible to align the mold 1 and the wafer 3 that do not transmit light, such as the Ni mold. Furthermore, after imprinting on one side of the substrate, imprinting can be performed on the back side with high positional accuracy, so that multi-layer patterning is possible.

In the microfabrication apparatus disclosed in Patent Document 2, conditions for processing are determined by pressing an original plate against a predetermined member before processing. As one of the processing conditions, it is shown that the relative angle between the original plate and the workpiece is measured. The conditions are the pressing force of the workpiece against the original, the distance of the workpiece relative to the original, the relative angle between the original and the workpiece, the temperature of the original, and the temperature of the workpiece.
Specifically, although not shown, a plurality of positions of the mold table are measured using a laser interferometer, and the angles ωX and ωY are calculated from the data. Thereby, it becomes possible to detect the inclination of the mold which was not measured in Patent Document 1.
JP 2000-323461 A JP 2005-26462 A

However, although alignment on the XY plane is possible, if there is an inclination between the mold and the transfer object as shown in FIG. 15, it cannot be detected, and the mold 1 remains on the resist 2 while being inclined. The resist 2 is cured as it is.
For this reason, as shown in FIG. 16, after the resist 2 is cured, the concavo-convex shape portion 7 is cured in an inclined state, but when the mold 1 is pulled up vertically, the transferred resist 2 is peeled off or falls down. As a result, the pattern of the mold 1 cannot be accurately transferred.
In particular, for high-aspect lattice-shaped optical devices that have been actively developed in recent years, if the concavo-convex portion 7 is hardened in a tilted state, the lattice may fall when the mold 1 is pulled up, so that the element performance is improved. It leads to deterioration.

Moreover, the measurement method as shown in Patent Document 2 does not directly measure the inclination of the mold surface, but only measures the inclination of the back surface of the mold table to which the mold is fixed. Absent.
Therefore, as in the case of Patent Document 1, since the tilt of the mold surface in contact with the wafer is not accurately detected, the mold may be pressed against the resist while being tilted. Therefore, when the mold is pulled up vertically after curing, the transferred resist is peeled off or falls down, and the pattern of the mold cannot be accurately transferred.
Therefore, in the present invention, the mold surface is pressed against the resist without being tilted by detecting the tilt and position of the mold surface and the surface of the transfer object that are in contact with each other during imprinting with high accuracy and a simple method. An object of the present invention is to provide a microfabrication apparatus that enables accurate transfer without peeling off or falling down.

In order to solve the above-mentioned problems, the invention according to claim 1 is a microfabrication apparatus that transfers a pattern formed on a mold by pressing the pattern onto the transfer object, and the inclination and position of the mold and the transfer object. And a control unit for controlling the posture of the mold relative to the transferred body from a signal obtained by the detecting means, and the mold and the transferred body are opposed to each other by the detecting means. It features a micromachining device that detects the tilt and position of a surface.
The invention according to claim 2 is characterized in that the detection means comprises a light source, a diffraction element, and a photodetector for receiving diffracted light.
According to a third aspect of the present invention, there is provided the microfabrication apparatus according to the second aspect, wherein the diffraction element for detecting the inclination of the mold and the transferred object is a diffraction element whose diffraction efficiency changes depending on the incident angle of light. Features.

The invention according to claim 4 is the microfabrication according to claim 2 or 3, wherein the photodetector is a plurality of two-divided photodetectors, and the dividing line directions of the photodetectors are parallel and on a straight line. Features the device.
The invention according to claim 5 is characterized in that the photodetector detects the + 1st order light and the −1st order light from the diffraction element, and the microfabrication apparatus according to any one of claims 2 to 4. To do.
The invention according to claim 6 is characterized in that the diffractive element is a diffractive element whose transmittance or diffraction efficiency changes depending on the incident position of light.
According to a seventh aspect of the present invention, the diffraction element for detecting the position and inclination of the mold is a reflection type diffraction element, and the diffraction element for detecting the position and inclination of the transferred body is transmissive. It is a type | mold diffraction element, The microfabrication apparatus of any one of Claim 2 thru | or 6 is characterized.

In the invention according to claim 8, the duty of the diffractive element changes so that the diffraction efficiency changes linearly within a range where the period is the same and the spot varies for position detection. Features the described microfabrication apparatus.
According to a ninth aspect of the present invention, in the light incident on the diffraction element, the spot diameter is reduced in a direction in which position detection is performed on the diffraction grating surface. Features the described microfabrication apparatus.
The invention according to claim 10 is the structure according to any one of claims 2 to 9, wherein the diffraction element has a structure in which diffraction gratings having different grating directions by 90 ° are laminated, and detects a tilt and a position in two perpendicular directions. Features the described microfabrication apparatus.

  According to the present invention, the microfabrication apparatus detects the inclination and the position of both the surface of the mold and the transferred object that are in contact with each other during imprinting, so that the mold can be pressed accurately and perpendicularly to the transferred object. The resist is prevented from peeling off or falling down at the time of peeling, so that the mold pattern can be accurately transferred. As a result, the yield is improved and the cost reduction effect is obtained.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic view showing a first embodiment of a microfabrication apparatus according to the present invention. FIG. 2 is a schematic view showing a diffraction element having a small period Λ and a deep groove in the transferred object side mark and the mold side mark. FIG. 3 is a curve diagram showing the intensity of the + 1st order light and the −1st order light of the light incident on the diffraction element.
A first embodiment of a microfabrication apparatus according to the present invention will be described with reference to FIGS. Here, description will be made assuming that a high-aspect lattice-shaped optical device is processed by nanoimprinting.
In FIG. 1, the microfabrication apparatus includes a mold 1 and a transfer object 2. The mold 1 has an uneven portion 7 serving as a mold and a mold side mark (reflection type diffraction element) 5 for tilt adjustment on its surface. The mold 1 is made of nickel electroforming or silicon. The mold side mark 5 is formed on the same surface as the surface on which the uneven portion 7 is present.
On the other hand, the transfer object 3 has a resist 2 (resin) coated on a glass substrate (or plastic). For example, PMMA (polymethyl methacrylate) is used as the resist (resin) 2. On the surface of the glass substrate, a transfer-receiving-side mark 6 for tilt adjustment is formed. The mold side mark 5 and the transfer target side mark 6 are diffractive elements, and have an irregular shape with a constant period.

In such a configuration, the laser beam is incident on the transfer-object-side mark 6 and the mold-side mark 5. Since the transferred object side mark 6 is a diffractive element, the incident laser beam generates ± first-order diffracted beams 9a and 9b. The ± first-order diffracted lights 9a and 9b are reflected by the surface of the mold 1 and received by the photodetectors 8a and 9d, respectively.
The light transmitted without being diffracted by the transfer target side mark 6 enters the mold side mark 5 and is reflected and diffracted. ± 1st order diffracted lights 10a and 10b are generated by reflection diffraction. ± 1st-order diffracted lights are received by the photodetectors 8b and 8c, respectively.
In order to detect the inclination and position of both the mold 1 and the transferred body 3, a light source (not shown), a diffraction element (the mold side mark 5 and the transferred body side mark 6), and a photodetector that receives the diffracted light. By using a detection system composed of 8a, 8b, 8c, and 8d, a small and low-cost detection system can be realized. Alignment can be performed in a short time because it can be detected only by detecting the intensity of light without observing with a camera such as a CCD or image processing.

By providing both the mold 1 and the transferred body 3 with diffractive elements (mold side mark 5 and transferred body side mark 6) whose diffraction efficiency changes depending on the incident angle of light, a difference in inclination from the incident laser light is detected. it can. Since it is sufficient to adjust only the emission direction of the reference laser beam, the variation is smaller than that in the method of detecting the inclination from data from a plurality of distance sensors.
Here, the transferred object side mark 6 and the mold side mark 5 are diffraction elements having a small period Λ and a deep groove as shown in FIG. In such a diffractive element, the intensity of the + 1st order light and that of the −1st order light are equal when the light is vertically incident, but when the light is incident at a tilt, the intensity of the + 1st order light and the −first order light is different (FIG. 3).
This is a feature of a volume hologram having a Q value of 1 or more. The Q value is an index representing the volume of the diffractive element. The wavelength of incident light is λ (in air), the groove depth of the diffractive element is T, the refractive index of the diffractive element medium is n, and the pitch is d. Sometimes Q = 2πλT / nd ² .
Therefore, the inclination of the mold 1 and the transfer target 3 can be detected by detecting the intensity difference between the + 1st order light and the −1st order light from the diffraction elements 5 and 6. If the outputs of the photodetectors 8a and 8d that receive the diffracted light from the transferred object side mark 6 are equal, the transferred object 3 is arranged perpendicular to the incident laser beam.

Furthermore, if the outputs of the light detector 8b that receives the diffracted light from the mold side mark 5 and the light detector 8c are equal, the mold 1 is disposed perpendicular to the incident laser light.
In such a state, the mold 1 and the transfer target 3 are completely parallel. If they are completely parallel, the resist (resin) 2 does not peel or fall during peeling, and the pattern of the mold 1 can be accurately transferred.
When the laser beam is incident and the output from the photodetector is not equal, the output from the photodetector is made equal by using a control means (not shown) for controlling the posture of the mold 1 or the transfer target 3. The tilt may be adjusted.
Since it is ideal that the Z direction when the mold 1 is pressed or peeled and the direction of the laser beam coincide with each other, basically, the inclination of the transferred body 3 is adjusted by the control means for controlling the posture with respect to the mold 1. It only has to be done. By making it possible to directly detect the inclination of the surface to be transferred and the surface to be transferred in this way, accurate inclination detection can be realized.

FIG. 4 is a schematic view showing a second embodiment of the microfabrication apparatus according to the present invention. In FIG. 4, the inclination ωZ (rotational deviation) around the Z axis can also be detected. In the first embodiment, the tilt direction around which the tilt of the mold 1 and the transferred body 3 can be detected by using the mold side mark 5 and the transferred body side mark 6 as diffraction elements is the tilt around the X axis or the Y axis. ωX and ωY.
In FIG. 4, the photodetectors 8a, 8b, 8c, and 8d are divided into two parts, and the diffracted light spots from the mold side mark 5 and the transferred object side mark 6 are on the dividing lines of the photodetectors 8a, 8b, 8c, and 8d. The output of the two-divided photodetectors 8a, 8b, 8c, and 8d is adjusted to be equal.
More specifically, the transfer object side mark 6 is rotated and adjusted around the Z axis, and the outputs of the photodetector 8a-1 and the photodetector 8a-2 that receive diffracted light, and the photodetector 8d-1 and the light detection are detected. The outputs of the units 8d-2 are made equal. The equal state is a state in which the dividing line direction of the photodetectors 8a and 8d and the lattice direction of the transferred object side mark 6 are perpendicular to each other.

Similarly, by rotating and adjusting the mold side mark 5 about the Z axis, the outputs of the photodetectors 8b-1 and 8b-2 that receive the diffracted light, the photodetectors 8c-1 and 8c- So that the outputs of 2 are equal.
The equal state is a state in which the dividing line direction of the photodetectors 8b and 8c and the lattice direction of the mold side mark 5 are perpendicular to each other. In such a state, the lattice direction of the mold side mark 5 and the transferred object side mark 6 coincide with each other, so that the inclination ωZ around the Z axis can be zero.
By receiving the diffracted light from the reflection type diffraction element (mold side mark) 5 and the transmission type diffraction element (transfer object side mark) 6 with a plurality of light receiving elements having the same dividing line direction, the mold 1 and the transfer object 3 Suppresses rotational deviation around the Z axis.
By detecting the inclination of the mold 1 and the transferred body 3 from the intensity difference between the + 1st order light and the −1st order light from the diffraction element whose diffraction efficiency changes depending on the incident angle of light, a highly sensitive tilt can be detected. Like that.

FIG. 5 is a schematic view showing a third embodiment of the microfabrication apparatus according to the present invention. FIG. 6 is a schematic diagram showing diffraction gratings having the same period and different duties. FIG. 7 is a characteristic diagram showing the duty (convex width / period) and diffraction efficiency of the diffraction grating of FIG.
In the first and second embodiments, the method of adjusting the inclinations ωX, ωY, and ωZ around the X axis, the Y axis, and the Z axis in the alignment of the mold 1 and the transfer target 3 has been described. The third embodiment shows a method for performing alignment in the X and Y directions. As shown in FIG. 5, a mold side mark 11 for alignment and a transfer target side mark 12 for alignment are provided.
Similar to the first embodiment, the alignment mold-side mark 11 is formed on the same surface as the surface having the concavo-convex shape 7, and the alignment-target-transfer-object-side mark 12 is a glass that is a transfer target. It is formed on the surface of a substrate (which may be plastic) 3.
The alignment-use mold-side mark 11 and the alignment-target-transfer-receiving-side mark 12 are diffractive elements, and have a concavo-convex shape with a constant cycle but different duty (convex width / cycle).
In such a configuration, laser light is incident on the transferred object side mark 12 for alignment and the mold side mark 11 for alignment. Since the transferred object side mark 12 for alignment is a diffractive element, the incident laser beam generates ± first-order diffracted beams 13a and 13b.
The ± first-order diffracted lights 13a and 13b are reflected by the surface of the mold 1 and received by the photodetectors 8e and 8h, respectively. The light transmitted without being diffracted by the transferred object side mark 12 for alignment is incident on the mold side mark 11 for alignment and is reflected and diffracted. ± 1st order diffracted lights 14a and 14b are generated by reflection diffraction. ± 1st-order diffracted beams 14a and 14b are received by photodetectors 8f and 8g, respectively.

Here, as shown in FIG. 6, the alignment mold-side mark 11 and the alignment-receiving-object-side mark 12 are diffraction gratings having the same period and different duties (convex width / period). Even if such a diffraction grating has the same period, the transmittance and the diffraction efficiency are different if the duty (width of the convex portion / period) is different.
As shown in FIG. 7, when the duty is small, the efficiency of the 0th order light is large and the efficiency of the ± 1st order light is small (the transmittance is large and the diffraction efficiency is small). As the duty increases, the efficiency of the zero-order light decreases and the efficiency of the ± first-order light increases (the transmittance is small and the diffraction efficiency is large). If this characteristic is used, the positions of the mold side mark 11 and the transfer target side mark 12 for alignment with the incident laser beam can be detected.
For example, in FIG. 6, if the position of the laser beam is shifted to the right side, the efficiency of ± 1st order light is increased because the laser beam passes through a grating having a large duty. On the other hand, if the position of the laser beam is shifted to the left side, the efficiency of the zero-order light is increased because the laser beam passes through a grating with a small duty. In this way, alignment in the X direction can be performed based on the position of the laser beam.

FIG. 8 is a schematic diagram showing a first example for increasing the alignment accuracy. FIG. 9 is a schematic diagram showing a second example for increasing the alignment accuracy. FIG. 10 is a schematic diagram showing a third example for increasing the alignment accuracy. FIG. 11 is a schematic diagram showing a fourth example for increasing the alignment accuracy.
In order to increase the alignment accuracy, as shown in FIGS. 8 and 9, the duty change may be increased or the laser beam spot diameter may be decreased. In this case, the duty may be changed along the lattice direction as shown in FIG. Even in such a configuration, the detection sensitivity can be increased by increasing the change in duty or reducing the spot diameter of the laser beam (FIG. 11).
In order to reduce the spot diameter of the laser beam, the spot diameter may be reduced on the surface of the diffraction element by using the laser beam as the convergent light. If the spot diameter of the laser beam is small, the transmittance and diffraction efficiency change greatly with respect to the movement of the diffractive elements 11 and 12, so that the sensitivity becomes high.

FIG. 12 is a schematic diagram showing a fifth example for increasing the alignment accuracy. FIG. 13 is a schematic diagram showing a sixth example for increasing the alignment accuracy. As shown in FIGS. 12 and 13, if the diffraction elements 11 and 12 are linear, alignment in one direction of the X direction or the Y direction can be performed.
In order to perform alignment in both the X direction and the Y direction, the gratings of the diffraction elements 11 and 12 may be orthogonal. For example, diffractive elements having a grating direction different by 90 ° are stacked so that the tilt and position in two directions of the X direction and the Y direction can be detected. In this way, it is possible to perform tilt alignment with the positions in both the X direction and the Y direction.
Furthermore, in the present invention, in order to detect the positions of the mold 1 and the transferred body 3 by a small and low-cost detection system, the transmittance (reflectance) is determined depending on the light incident position on the mold 1 and the transferred body 3. ), Diffraction elements 11 and 12 whose diffraction efficiency changes are formed.
Accordingly, since alignment can be performed by using the diffraction elements 11 and 12 whose transmittance (reflectance) and diffraction efficiency change depending on the incident position of light, observation with a camera such as a CCD and image processing are not required. Since it can be detected only by detecting the intensity of light, the alignment mechanism can be realized at a low cost.

In the present invention, as described above, the reflective diffractive element (mold side mark) 5 is used to detect the position and tilt of the mold 1, and the transmission diffraction is used to detect the position and tilt of the transfer object. The element (transfer object side mark) 6 is used.
As a result, the alignment and tilt adjustment of the mold 1 and the transfer target 3 can be performed with reference to the incident light position. Since the reference is the position of the same incident light, alignment with higher reliability can be performed as compared with the case of alignment with a plurality of sensors.
In the present invention, the diffraction elements 11 and 12 whose transmittance (reflectance) and diffraction efficiency change depending on the incident position of light have the same period, and the diffraction efficiency is within a range in which the spot varies for position detection. Since the diffractive element whose duty (= convex portion / period) changes so as to change linearly is used, the diffractive element can be manufactured at low cost, and the cost of the apparatus can be reduced.
Furthermore, in the present invention, the light incident on the diffractive elements 11 and 12 is converged light, thereby reducing the spot diameter on the surfaces of the diffractive elements 11 and 12 and increasing the alignment sensitivity. As a result, the transmittance or diffraction efficiency greatly changes even with minute fluctuations of the diffraction elements 11 and 12, and the alignment sensitivity can be increased.

Schematic which shows 1st Embodiment of the microfabrication apparatus by this invention. FIG. 3 is a schematic diagram showing a diffraction element having a small period Λ and a deep groove in a transfer-object-side mark and a mold-side mark. The curve figure which shows the intensity | strength of the + 1st order light of the light which injects into a diffraction element, and -1st order light. Schematic which shows 2nd Embodiment of the microfabrication apparatus by this invention. Schematic which shows 3rd Embodiment of the microfabrication apparatus by this invention. Schematic which shows the diffraction grating from which a period is equal and duty (duty) differs. The characteristic view which shows the duty (convex part width / period) and diffraction efficiency of the diffraction grating of FIG. Schematic which shows the 1st example for raising alignment accuracy. Schematic which shows the 2nd example for raising alignment accuracy. Schematic which shows the 3rd example for raising alignment accuracy. Schematic which shows the 4th example for raising alignment accuracy. Schematic which shows the 5th example for raising alignment accuracy. Schematic which shows the 6th example for raising alignment accuracy. Schematic which shows the microfabrication apparatus of a prior art. Schematic which shows the state which the mold substrate of FIG. 14 inclined. Schematic which shows the state pressed on the workpiece in the state in which the mold substrate of FIG. 14 inclined.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Mold, 2 Resin, 3 Glass substrate, 4 Mold substrate, 5 Reflection type diffraction element, 6 Transmission type diffraction element, 7 Uneven shape, 8a, 8b, 8c, 8d Photodetector, 9a, 9b Diffracted light, 10a, 10b Reflected diffracted light, 11 reflective diffractive element, 12 transmissive diffractive element

Claims (10)

  In a micromachining apparatus that presses and transfers a pattern formed on a mold to a transfer target, a detection unit that detects the inclination and position of the mold and the transfer target, and a signal obtained by the detection unit And a control means for controlling the posture of the mold relative to the transfer body, wherein the detection means detects the inclination and position of the opposing surfaces of the mold and the transfer body.   2. The microfabrication apparatus according to claim 1, wherein the detection means includes a light source, a diffraction element, and a photodetector for receiving diffracted light.   3. The microfabrication apparatus according to claim 2, wherein the diffraction element for detecting the inclination of the mold and the transfer object is a diffraction element whose diffraction efficiency changes depending on the incident angle of light.   4. The microfabrication apparatus according to claim 2, wherein the photodetector is a plurality of two-divided photodetectors, and the dividing line directions of the photodetectors are parallel and on a straight line.   5. The microfabrication apparatus according to claim 2, wherein the photodetector detects + 1st order light and −1st order light from the diffraction element. 6.   3. The microfabrication apparatus according to claim 2, wherein the diffraction element is a diffraction element whose transmittance or diffraction efficiency changes depending on the incident position of light.   The diffraction element for detecting the position and inclination of the mold is a reflection type diffraction element, and the diffraction element for detecting the position and inclination of the transfer object is a transmission type diffraction element. The microfabrication apparatus according to any one of claims 2 to 6.   8. The microfabrication apparatus according to claim 6, wherein the diffraction element has a duty that changes so that diffraction efficiency changes linearly within a range in which the period is the same and a spot varies for position detection. .   9. The microfabrication apparatus according to claim 2, wherein the light incident on the diffraction element is light having a reduced spot diameter in a direction in which position detection is performed on the diffraction grating surface. .   10. The microfabrication apparatus according to claim 2, wherein the diffraction element has a structure in which diffraction gratings having different grating directions by 90 ° are stacked, and detects a tilt and a position in two perpendicular directions. .

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