JP2949651B2 - Method of manufacturing electrode substrate and recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode substrate used for a high density recording medium and a method for manufacturing the recording medium. More specifically, the present invention relates to a method for manufacturing an electrode substrate for forming a recording medium and a method for manufacturing a recording medium in an information processing apparatus to which a scanning tunneling microscope (STM) is applied.

[0002]

2. Description of the Related Art In recent years, with the development of the information society, the development of large-capacity memories has been very actively performed. In general, the performance required of the memory is 1) high density and large recording capacity 2) fast response time of recording and reproduction 3) low power consumption 4) high productivity and low price.

On the other hand, recently, a scanning tunneling microscope (S
TM) was developed (G. Binnig et al.
Phys. Rev .. Lett. 49, 57 (198
2)), high resolution measurement in real space can be performed regardless of whether it is a single crystal or non-crystal.

[0004] Such STM utilizes the fact that a tunnel current flows when a voltage is applied between a metal probe (probe electrode) and a conductive material to approach a distance of about 10 °. This current is very sensitive to changes in the distance between the two, and by scanning the probe so as to keep the tunnel current constant, it is possible to draw the surface structure in real space, and at the same time, to observe various electron clouds related to the total electron cloud of surface atoms. Information can also be read. The resolution in the in-plane direction at this time is about 1 °.

Therefore, if the principle of STM is applied,
It is possible to perform high-density recording / reproduction sufficiently in the atomic order (several Å). As a recording / reproducing method at this time, recording is performed by changing the surface state of an appropriate recording layer using a high energy electromagnetic wave such as a particle beam (electron beam, ion beam) or X-ray and an energy beam such as visible / ultraviolet light. The recording and reproduction are performed by using a material having a memory effect on the switching characteristics of voltage and current, for example, a thin film layer of a π-electron organic compound or chalcogenide as a recording layer.
A method using a TM has been proposed (Japanese Unexamined Patent Publication No.
No. 1615523). In addition, there is proposed a method and an apparatus for capturing molecules from a fluid on a substrate by applying a voltage pulse, selectively writing data bits, and reading and erasing the data bits (Japanese Patent Application Laid-Open No. Hei 1-196751). ).

Incidentally, in order to actually perform recording and reproduction on a memory medium as an apparatus, it is necessary to perform so-called tracking positioning and tracking to a data string. As a method of manufacturing an electrode substrate having a track of this kind of high-density memory, 1) forming a track on the electrode substrate by using lithography technology 2) applying an atomic arrangement of crystals 3) a conductor track as a recording medium 4) A concave or convex portion is formed on a base material, a metal layer is deposited on the base material, and then the metal is peeled off, and the peeled surface is used as an electrode surface.

[0007]

When the electrode substrate shown in the above conventional example is used, it has been difficult to maintain a smooth surface of the base material without being affected by resist residues and the like.

That is, the object of the present invention is to
An object of the present invention is to provide a method for manufacturing an electrode substrate and a recording medium that can solve the above-described problems in the related art.

[0009]

According to a first aspect of the present invention, there is provided a method of forming a metal on a base material, and forming the metal on a transfer material on which a track pattern is separately formed. A method for manufacturing an electrode substrate, comprising a step of peeling off and then forming a track by blowing gas or air or suctioning from the back surface of the transfer material.
Wherein the method further comprises the step of forming the electrode substrate by epitaxially growing a metal on a cleavage plane of a crystal substrate. The method of manufacturing an electrode substrate according to the first aspect, A method for producing a recording medium, comprising the step of providing a recording layer on an electrode substrate produced by the method for producing a second electrode substrate; The method of manufacturing a recording medium according to the third aspect, wherein the method is a method of manufacturing a recording medium.

That is, according to the present invention, a step of forming a metal on a base material, the metal is peeled off on a transfer material on which a track pattern is separately formed, and then a gas or air is blown or suctioned from the back surface of the transfer material. With the step of forming tracks by the method, an electrode substrate can be manufactured from a base material that is not affected by resist residues.

Hereinafter, the present invention will be described in detail. FIG.
FIG. 3 is a cross-sectional view illustrating each step of manufacturing an electrode substrate having a track according to the present invention. 101 is a base material, 10
2 is an electrode layer, 103 is a transfer material, 104 is a track pattern, and 105 is an adhesive. In FIG. 1, first, the STM
To perform high-speed, high-density recording utilizing the characteristics of
An electrode substrate capable of realizing N ratio and high-speed recording and reproduction is required. In the present invention, it is also possible to use a peeled surface in which the electrode layer is peeled from the base material, and it is preferable that the base material has a smooth surface. For example, 1) a cleavage plane of a crystal: mica, MgO, TiC, S
i, graphite, etc. 2) Fused glass surface: float glass, Corning # 7059, fused quartz, etc.

The surfaces of these various materials can be observed using an atomic force microscope (AFM). Such AF
M can measure the surface shape of a sample at a resolution of an atomic order regardless of the conductivity or insulation of the sample. The present inventors have observed the surface shape of various materials using AFM, and found that the surface unevenness was 1 nm or less in a 10 μm square region, and was found to be suitable as a base material used in the present invention.

The peeling method may be eutectic bonding, electroforming, or the like, in addition to peeling off using an adhesive. Such an adhesive is preferably a solventless type that does not cause volume shrinkage, and examples thereof include an epoxy resin and a polyimide resin.

Next, the electrode layer 102 preferably has high conductivity. For example, a metal such as Au, Ab, Pt, and Pd, an alloy such as Au-Pd, and Pt-Pd, and a stacked film thereof can be given. As a method of forming an electrode using such a material, a conventionally known method of forming a thin film is sufficient.

On the other hand, the track pattern 10
As a method of forming 4, there is a method of selectively irradiating the transfer material with light energy, a method of discharging in an electrolytic solution, and a method of forming a hole in glass. In addition, a conventionally known lithography technique can be used.

[0016]

Embodiments of the present invention will be described below.

(Example 1) First, mica is cleaved in the air to obtain a base material 101. Subsequently, Au is epitaxially grown on the substrate 101 by a vacuum evaporation method to form an electrode layer 102. The electrode layer 102 has a substrate temperature of 400
° C, deposition rate 10Å / sec, ultimate pressure 2 × 10 ^-6 To
The film was formed under the conditions of rr and a film thickness of 2000 °.

Meanwhile, SiO ₂ is 1 as a transfer material 103
A silicon substrate having a thickness of 000 ° was used. As shown in FIG. 3, XeC of 10 J / cm ² was used as a light energy source.
When the laser beam is oscillated at 100 Hz and condensed to a diameter of 1 μm by the lens 4 using an excimer laser, silicon at the condensed portion on the transfer material 103 is removed by evaporation, and a penetration resistance is formed (FIG. 1B). Subsequently, a desired track pattern was formed by sweeping light.

An adhesive 105 (trade name) is placed on the transfer material.
After applying High Super 5 (Cemedine), the base material 101 is arranged on the adhesive 105 so as to face the electrode material, and the electrode layer 102 is attached on the transfer material (FIG. 1C). Adhesion is 3kg
/ Cm ² , room temperature, and a curing time of 24 hours. continue,
The base material 101 is peeled from the electrode layer 102, and the transfer material 10
3. An electrode substrate composed of the electrode layer 102 and the adhesive 105 was obtained (FIG. 1D).

Next, 5 kg / g from the separated electrode layer.
By blowing N ₂ gas of cm ² , a concave track pattern was formed (FIG. 1E).

When the surface of the electrode substrate formed by the above-described method was observed by STM, a concave track pattern was formed at 10 μm square, and the tracks could be clearly identified.

Embodiment 2 As shown in FIG. 2, a fused quartz substrate is washed to obtain a base material 101. Au on such a base material
Is formed to a thickness of 2000 ° by a vacuum evaporation method to form an electrode layer 102. The deposition conditions at this time were a substrate temperature of 400 ° C., a deposition rate of 10 ° / sec, and an ultimate pressure of 2 × 10 ⁻⁶ Torr.

[0023] On the other hand, SiO ₂ is 1μ as a transfer material 103
An m-formed Si substrate was used. After the transfer material was washed, an EB resist (trade name: OEBR-1000, manufactured by Tokyo Ohka) was applied, exposed, and developed to form a desired track pattern 104 (FIG. 2B). The EB drawing conditions were an acceleration voltage of 20 kV and a dose of 50 μC / cm ² . Subsequently, etching of SiO ₂ was performed using the resist pattern as a mask. Etching depth 1000 °, pressure 5P using CF ₄ as etching gas
a, conditions of 150 W of discharge power. Thereafter, the resist was peeled off using methyl ethyl ketone to form a concave track pattern 104. Thereafter, peeling of the electrode layer and formation of the track pattern were performed in the same manner as in Example 1. At this time, compressed air of 5 kg / cm ² was blown from above the electrode surface.

When the surface of the electrode substrate formed by the above method was observed by STM, a concave track pattern was formed at 10 μm square, and the tracks could be clearly identified. Further, it was found that the transfer material could be used repeatedly.

(Example 3) As in Example 2, a fused quartz substrate was used as a base material, and Au was formed to a thickness of 2000 as an electrode layer. However, the substrate temperature at the time of vapor deposition was room temperature, and after forming the electrode layer, the base material was heated to 600 ° C. for 1 minute. Then, it returned to room temperature.

Next, the electrode layer was peeled off from the transfer material formed in the same manner as in Example 1. Thereafter, the electrode layer was suctioned from the back surface of the transfer material using a suction device to form a concave track pattern. The suction pressure at this time was 5 kg / cm ² .

When the surface of the electrode substrate formed by the above method was observed by STM, a concave track pattern was formed at 10 μm square, and the tracks could be clearly identified.

Example 4 An electrode substrate was formed in the same manner as in Example 1. Next, a four-layer polyimide LB film was formed on the electrode substrate to form a recording layer 107 (FIG. 4).
(F)). Hereinafter, a method for forming the polyimide LB film will be described.

First, polyamic acid was dissolved in N, N'-dimethylacetamide (concentration in terms of monomer of 1 × 10
^-3 M) and 1 × 10 ⁻³ M solvent of N, N′-dimethyloctadecylamine separately prepared with the same solvent in a ratio of 1: 2 (V
/ V) to prepare an octadecylamine polyamic acid salt solution.

The solution was spread on an aqueous phase consisting of pure water at a water temperature of 20 ° C. to form a monomolecular film on the water surface. After removing the solvent by evaporation, the surface pressure was increased to 25 mN / m. While keeping the surface pressure constant, the above electrode substrate was gently immersed in a direction crossing the water surface at a speed of 5 mm / min.
The film was gently pulled up at a rate of / min to form a two-layer Y-type monomolecular cumulative film. By repeating this operation, a four-layer monomolecular cumulative film of polyamic acid octadecylamine salt was formed. This substrate was heated and baked at 300 ° C. for 10 minutes under reduced pressure to imidize the octadecylamine polyamic acid salt, thereby obtaining a four-layer polyimide monomolecular film.

Next, when the surface shape of the recording medium prepared by the above-described method was examined by the information processing apparatus shown in FIG. 5, the surface of the recording medium reflected the smooth surface of the electrode. The surface unevenness was 1 nm or less.

Next, an experiment of recording and reproduction was performed using the apparatus shown in FIG. A probe electrode made of platinum-rhodium was used as the probe electrode 202. This probe electrode controls the distance Z to the surface of the recording layer 107,
The distance Z is finely controlled by the piezoelectric element so as to keep the current constant. Further, the linear actuator 20
Reference numerals 4, 205, and 206 are designed so that fine movement control can be performed in the in-plane (X, Y) direction while keeping the distance Z constant. The probe electrode can directly perform recording / reproduction and erasing.

On the other hand, the recording medium is placed on a high-precision XY stage 201 and can be moved to an arbitrary position. The above-described recording medium is placed on the XY stage, and a positive electrode is provided between the probe electrode and the electrode layer 102 of the recording medium.
A voltage of 1.5V is applied, current monitor while 10 ^-10 A ≧ probe electrode I _P for controlling the distance Z between the probe electrode 202 and the recording layer 107 surface I _P ≧ 10 ^-11 A
It was set to become.

Next, the probe electrode 202 is connected to the recording layer 107.
While scanning on the above, information was recorded at a pitch of 100 °. The recording of such information is performed by setting the probe electrode 202 to +
With the electrode layer 102 on the negative side and the material having a memory effect on the switching characteristics of the current / voltage characteristics (electric memory material: 4 layers of polyimide LB film), the material has a low resistance state (ON).
(State) shown in FIG. 6 was applied.

Thereafter, the probe electrode was returned to the recording start point, and the recording layer 107 was scanned again. At this time, when reading out the record, adjustment was made so that Z = constant. As a result, it was shown that a probe current of about 10 nA flowed in the data bit, and the data bit was turned on.

After the probe voltage is changed from the ON state of the electric memory material to the OFF state by applying the pulse voltage shown in FIG. 7, the recording position is traced again. It was also confirmed that the state had changed.

[0037]

As described above, according to the present invention, an electrode surface formed on a base material is transferred onto a transfer material on which a track pattern has been formed in advance, and is blown or sucked by gas or air. Since the track pattern is formed on the transfer material and the electrode substrate having the track is formed, the base material is not affected by the resist residue or the like,
It has become possible to form an electrode substrate having tracks without impairing the smoothness of the base material.

[Brief description of the drawings]

FIG. 1 is a process chart of an electrode substrate manufacturing method according to the present invention.

FIG. 2 is a manufacturing process diagram according to the embodiment of the present invention.

FIG. 3 is a schematic view of an apparatus used in an embodiment of the present invention.

FIG. 4 is a manufacturing process diagram in the example of the present invention.

FIG. 5 is a configuration diagram of an information processing apparatus to which STM is applied.

FIG. 6 is a diagram showing a waveform of an electric pulse required to cause a recording layer of a recording medium formed by the manufacturing method of the present invention to transition from a high resistance state to a low resistance state.

FIG. 7 is a diagram showing a waveform of an electric pulse necessary for returning a low resistance state portion on a recording layer of a recording medium formed by the manufacturing method of the present invention to a high resistance state again.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Optical energy source 2 Light 3 Mirror 4 Lens 101 Base material 102 Electrode layer 103 Transfer material 104 Track pattern 105 Adhesive 106 Peeling substrate 107 Recording layer 201 XY stage 202 Probe electrode 203 Probe electrode support 204 Probe electrode in Z direction Z axis linear actuator to be driven 205 Linear actuator to drive the XY stage in the X direction 206 Linear actuator to drive the XY stage in the Y direction 301 Amplifier 302 Logarithmic compressor 303 Low-pass filter 304 Error amplifier 305 Driver 306 Drive circuit 307 High-speed passage filter

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshihiro Yanagisawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Haruki Kawada 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (56) References JP-A-3-156749 (JP, A) JP-A-2-199252 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G11B 9/00

Claims (4)

(57) [Claims] A step of forming a metal on a base material, and peeling the metal onto a transfer material on which a track pattern is separately formed;
A method for manufacturing an electrode substrate, comprising a step of forming tracks by spraying gas or air or suctioning from the back surface of the transfer material. 2. The method according to claim 1, further comprising the step of forming the electrode substrate by epitaxially growing a metal on a cleavage plane of a crystal substrate. 3. A method for manufacturing a recording medium, comprising a step of providing a recording layer on an electrode substrate manufactured by the method for manufacturing an electrode substrate according to claim 1. 4. The method according to claim 3, wherein the step of forming the recording layer is a Langmuir-Blodgett method.