JPH11186142A - Method and device for forming pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pattern forming method for realizing the patterning of the scale of not more than several tens nanometers on a resist film with sufficient thickness with which the defect of a pin hole is difficult to occur. SOLUTION: Resist 14 or a thin film are applied onto a substrate 10 and a probe 1 whose tip is sharpened is brought into contact with resist 14 or the thin film. Contact force between the probe 1 and resist 14 or the thin film is controlled so that the contact force of more than the plastic deformation yield point of resist 14 or the thin film operates between the probe 1 and the thin film and it relatively moves the probe 1 and the substrate 10, and the resist 14 or the thin film are plastically deformed and directly patterned.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of fine processing of a surface and a method of cutting a recording substrate, and more particularly to a fine processing of a scale of several tens of nanometers or less and a high-speed recording / reproduction of a recording bit of a size of several tens of nanometers or less. The present invention relates to a recording substrate cutting method and apparatus for the same.

[0002]

2. Description of the Related Art In recent years, the progress of the information society has been remarkable,
There is a demand for the development of technology that can store more information. At present, in the field of research on semiconductor devices and file memories, miniaturization and densification on the order of tens of nanometers or less are being promoted. A promising candidate is a scanning tunneling microscope (Scanning Tunneling Mi).
There is a technique of a scanning probe microscope represented by, for example, (crossscope: STM). The technique of the scanning tunneling microscope is disclosed in detail in U.S. Pat. No. 4,343,993. Focusing on the principle of enabling spatial resolution down to the atomic size and microfabrication down to the atomic size, application to semiconductor device manufacturing technology and recording technology on the scale of several tens of nanometers or less has been vigorously pursued. In addition, Physical Review Letters (Physical Review)
w Letters) Vol. 56 (1986) No. 930
Atomic Force Microscope (Atomic F
The use of the technology of Ace Microscope (AFM) has also been energetically studied.

[0003]

In order to form a fine pattern, a method of applying a resist on a substrate on which a pattern is to be finally formed, drawing the resist with a mask or EB, and developing the resist is used. The thinner the resist film is, the more advantageous for miniaturization. However, thinning the resist causes defects such as pinholes, which is disadvantageous in practical use.

An object of the present invention is to solve the technical problems of the above-mentioned prior art and to provide a novel pattern forming method and apparatus having a scale of several tens of nanometers or less. In other words, by applying a contact force above the plastic deformation yield point to a resist or thin film of an appropriate thickness, the resist or thin film is plastically deformed and directly patterned, thereby enabling patterning on a scale of several tens of nanometers or less. It is to provide a forming method and an apparatus.

[0005]

According to the present invention, a resist or a thin film is coated on a substrate, and a tip having a sharpened tip is brought into contact with the resist or the thin film, and a contact force between the probe and the resist or the thin film is formed. Plastic deformation of resist or thin film Directly patterning by controlling the contact force above the yield point between the probe and the thin film and moving the probe and the substrate relatively, plastically deforming the resist or the thin film .

Using the resist or thin film patterned by the plastic deformation as a mask, the mask pattern can be transferred to the substrate by etching or a lift-off process to form a pattern on the substrate.

[0007] The thin film has a multilayer resist structure, and the outermost resist layer can be plastically deformed and patterned.

The contact force between the probe and the thin film can be controlled so as to selectively take one of two contact forces, which are equal to or higher than the yield point of the thin film and equal to or lower than the yield point.

The relative movement of the probe and the substrate can be performed along either a rotating coordinate system or a rectangular coordinate system.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A probe sharpened to several tens of nanometers or less is brought into contact with a thin film, for example, a substrate having a resist film. By using a probe harder than the resist and controlling the contact force to be equal to or higher than the yield point of the plastic deformation of the resist, only the resist is plastically deformed. Thus, a pattern having the same size as the tip of the probe can be formed on the resist film.

[0011] While relatively moving the substrate and the probe, the contact force is controlled so as to be a constant value equal to or higher than the yield point of plastic deformation, and the width of the resist film is maintained at a constant width of several tens of nanometers or less. Groove can be formed. Alternatively, while the substrate and the probe are relatively moved, a pulse having a size of several tens of nanometers or less is formed in the resist film by performing pulse modulation so that the contact force becomes a value equal to or higher than the yield point of plastic deformation at an arbitrary position. Can be formed. Also, while moving the substrate and the probe relatively, the contact force is controlled so as to be a constant value equal to or higher than the yield point of plastic deformation, and the groove that keeps the width of several tens of nanometers or less almost constant in the resist film And by modulating the pulse so that the contact force becomes a larger value at an arbitrary position, it is possible to form a hole deeper than the groove at a desired position of the groove having a substantially constant width in the resist film. it can.

Hereinafter, embodiments of the present invention will be specifically described.

Embodiment 1 FIG. 1 is a schematic view showing an example of a pattern forming apparatus using the above-mentioned technique of an atomic force microscope. In the figure, a substrate 10 having a surface coated with a resist 14 is
It is held at 1. The rotation drive device 11 is held in a housing of a device not shown. The probe 1 is provided so as to face the resist 14. The probe 1 is formed at the tip of the leaf spring 2, and the base of the leaf spring 2 is a pulse modulator 8.
Is held. The pulse modulator 8 is held by a Z-direction fine movement device 13, and the Z-direction fine movement device 13 is
Is held. The radial fine movement device 12 is the rotary drive device 1
As in the case of 1, the device is held by an arm (not shown) in the housing of the device not shown. While rotating the substrate 10 by the rotation driving device 11, the radial fine movement device 12
Is moved in the radial direction by an arm (not shown), and
The relative position between the resist 14 and the probe 1 can be controlled arbitrarily and accurately by controlling the position in the radial direction with a signal (not shown) applied to the radial direction fine adjustment device 12. Laser light emitted from the laser diode 3 is condensed by a lens 4 on the opposite side of the surface of the leaf spring 2 on which the probe 1 is provided, and displacement of reflected light from the lens 4 is sensed by a position sensor 5. The output of the position sensor 5 changes due to a change in the contact force between the probe 1 and the resist 14. The detected output of the position sensor 5 is amplified by a preamplifier 6 and applied to a servo circuit 7. A target value corresponding to the contact force is set in the servo circuit 7, and a drive signal is output to the Z-direction fine movement device 13 so that the signal from the position sensor 5 matches this target value. The Z-direction fine movement device 13 is constituted by a piezo element, and moves the root of the leaf spring 2 in the Z-direction via the pulse modulator 8 according to the sign and magnitude of the drive signal given from the servo circuit 7. Thereby, the contact force between the probe 1 and the resist 14 is controlled to a constant value.
The pulse modulator 8 is composed of a piezo element, and a pulse modulation signal is added to the pulse modulator 8 from a pulse driving circuit 9. The polarity of the pulse modulation signal is selected so that the root of the leaf spring 2 is moved in the Z direction so as to increase the contact force between the probe 1 and the resist 14. Since the frequency characteristic of the servo circuit 7 is designed not to respond to the frequency of the modulation pulse, the movement of the probe 1 can be pulse-modulated by the pulse modulator 8 even during servo control.

Next, the substrate 10, the resist 14, and the probe 1 of this embodiment will be described. It is desired that the substrate 10 has a surface flatness of several nanometers or less. A single crystal silicon substrate has excellent flatness and is an optimal material. Therefore, a single crystal silicon substrate was used as the substrate 10. As the resist 14, polymethacrylate (PMMA), which is a positive resist material usually used for electron beam drawing, was used. PMMA was spin-coated on a silicon substrate so as to have a thickness of 50 nm to 100 nm, for example, 50 nm. The probe 1 is preferably harder than the resist 14 and has a tip sharpened to several tens of nanometers or less. A probe made of silicon, silicon oxide, or silicon nitride used in an AFM or the like is preferable. Available. Normally, the probe 1 is formed integrally with the leaf spring 2 by a semiconductor process, and the tip of the probe 1 can be formed with a radius of curvature of 20 nm or less. In this embodiment, the probe is made of silicon nitride.

FIG. 3A shows that the probe 1 and the substrate 10 are relatively rotated by using the rotary driving device 11 and the radial fine movement device 12 so that the contact force is constant at or above the yield point of plastic deformation. By controlling the resist 14 to a value, the resist 14
FIG. 2 shows a cross section and a perspective view of a part of the groove 16 when the groove 16 having a width of 20 nm or less is formed in a circular or spiral shape. Since the groove 16 is formed by plastic deformation, bulges are simultaneously formed on both sides thereof.

FIG. 3 (c-1) shows that the pulse modulator 8 and the pulse drive circuit 9 are used while forming the groove 16 by controlling the contact force to be a constant value equal to or higher than the yield point of plastic deformation. A state in which a hole 17 having a size of 20 nm or less is formed at the position where the pulse is applied together with the formation of the groove 16 by pulse-modulating the contact force to further strengthen the contact force is shown in cross-sectional and perspective views. FIG. 3C-2 shows a cross-sectional shape of the resist along the bottom of the groove 16.
The hatched portion is the cross-sectional shape of the resist. It can be seen that the resist at the bottom of the hole 17 is thinner than the bottom of the groove 16.

FIG. 3 (b) shows the pulse modulator 8 and the pulse drive circuit at a predetermined position while controlling and rotating the contact force so that the contact force does not reach the yield point of the plastic deformation. 9 by pulse-modulating the contact force so that the contact force exceeds the yield point of plastic deformation.
A state in which only the hole 17 having a size of 0 nm or less is formed in the resist 14 is shown in a sectional view and a perspective view.

Using the resist pattern formed on the resist film in this embodiment, it was possible to transfer to the surface of the silicon substrate 10 by fluorine-based reactive ion etching.

Embodiment 2 FIG. 2 is a schematic view of a pattern forming apparatus of an embodiment in which relative movement between a probe 1 and a substrate 10 is performed along a rectangular coordinate system. X
The operation of each unit other than the YZ-direction driving device 15 is substantially the same as in the first embodiment. The XYZ direction driving device 15 is a probe 1
Fine movement in the Z direction for controlling the contact force between the resist and the resist 14 to a constant value, and movement in the XY directions for performing relative movement in a two-dimensional orthogonal coordinate system. In this embodiment, when the size of the substrate is increased, it is preferable to have a moving mechanism for moving in the X and Y directions, as in the embodiment of FIG.

In the case of the apparatus shown in FIG. 2, by controlling the movement in the X and Y directions while appropriately controlling the contact pressure between the probe 1 and the resist 14, the grooves 16 and holes 17 similar to those shown in FIG. Could be formed.

Embodiment 3 In this embodiment, a silicon single crystal substrate is used as the substrate 10 and about 100
A silicon oxide film having a thickness of nm was grown. A 50 nm-thick PMMA was applied as a first resist 18 on the surface to form a two-layer resist structure. A hole 17 having a diameter of about 20 nm is formed in the first resist 18 by the method of the first or second embodiment.
Was formed. FIG. 4A is a cross-sectional view of the substrate showing this state. Next, as shown in FIG. 4B, holes were able to penetrate the second resist 19 to the surface of the substrate 10 with a high aspect ratio by dry etching. afterwards,
By the lift-off process, as shown in FIG.
Metal dots 20 of 0 nm or less could be formed on the substrate 10.

[0022]

As described above, according to the present invention, since the thin film is patterned by plastic deformation by controlling the contact pressure between the thin film and the probe, the tip of the probe can be sufficiently sharpened. Even if the thin film is thick, a pattern with a size of several tens of nanometers or less can be formed on the thin film, and fine processing on a scale of several tens of nanometers or less and high-speed recording / reproduction of recording bits with a size of several tens of nanometers or less can be performed. The method for cutting the recording substrate for the purpose can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram illustrating a configuration of an apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic block diagram illustrating a configuration of an apparatus according to a second embodiment of the present invention.

FIG. 3A is a diagram showing a groove formed by the apparatus of the first and second embodiments in a cross-sectional and perspective view, and FIG.
And (c-1) shows the grooves and holes formed by the devices of Examples 1 and 2 in the form of a cross section and a perspective view, respectively. Figure,
(C-2) is a view showing a cross section of a groove and a hole formed by the devices of Examples 1 and 2.

4A is a cross-sectional view showing a hole pattern on a first resist formed in Example 3, FIG. 4B is a cross-sectional view after dry etching, and FIG. 4C is a view showing a state after lift-off.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 probe, 2 leaf spring, 3 laser diode, 4 lens, 5 position sensor, 6 preamplifier, 7 servo circuit, 8 pulse modulator, 9 pulse drive circuit, 1
0 ... substrate, 11 ... rotary drive, 12 ... radial fine movement device, 13 ... Z direction fine movement device, 14 ... resist, 15 ... X
YZ direction driving device, 16: groove, 17: hole, 18: first resist, 19: second resist, 20: dot.

Claims (7)

[Claims] An apparatus according to claim 1, wherein a probe having a sharpened tip is brought into contact with a thin film applied to the surface of the substrate, and the probe and the substrate are relatively moved while controlling the contact force. A pattern forming method, wherein the thin film is plastically deformed and directly patterned by controlling the contact force acting on the thin film to be a contact force equal to or higher than the plastic deformation yield point of the thin film. 2. The pattern forming method according to claim 1, wherein the mask pattern is transferred to the substrate by etching or a lift-off process using the patterned thin film as a mask. 3. The pattern forming method according to claim 1, wherein the thin film has a multilayer resist structure, and the outermost resist layer is patterned. 4. The pattern forming method according to claim 1, wherein the relative movement between the probe and the thin film is in a rotating coordinate system or a rectangular coordinate system. 5. A holding means for holding a substrate having a surface coated with a thin film, a cantilever for holding a probe disposed at the tip end facing the thin film surface, and a probe for holding a base of the cantilever. The control means for controlling the contact force on the thin film, and a moving means for holding the control means and moving the probe relative to the thin film surface,
The pattern forming apparatus according to claim 1, wherein the control means controls the contact force acting on the thin film at a desired position of the probe so as to be equal to or higher than a plastic deformation yield point of the thin film. 6. The pattern forming apparatus according to claim 5, wherein said control means includes a feedback mechanism for controlling the contact force to be constant, and said modulator includes a modulator for modulating the contact force at a frequency at which the feedback mechanism does not substantially respond. apparatus. 7. The pattern forming apparatus according to claim 5, wherein the relative movement between the probe and the thin film is in a rotating coordinate system or a rectangular coordinate system.