JPH10340490A - Electrode substrate, recording medium and production of those - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain high S/N and to realize fast reproducing by forming a metal electrode layer on a substrate having a smooth surface and peeling the metal electrode layer from the substrate so that the surface state of the smooth surface of the substrate is transferred to the metal electrode layer of a multilayered electrode substrate. SOLUTION: A metal electrode layer 105, a low thermal expansion layer 104, and a high heat conductive layer 103 are successively formed on a first substrate 109 having a smooth surface. An adhesive layer 102 and a high heat conductive layer 103 are formed on a second substrate 101. The first substrate 109 and the second substrate 101 are laminated with each high heat conductive layers 103 facing each other and adhered by pressing and heating. Then the first substrate 109 is peeled from the interface with the metal electrode layer 105 to obtain an electrode substrate 107 having a smooth surface. Then a recording layer 106 is formed on the metal electrode layer 105 to obtain a recording medium 108. By using the obtd. medium, the error rate of read-out data can be largely decreased owing to the smoothness of the substrate and the suppressing effect on heat emission and thermal expansion during recording and reproducing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrode substrate, a recording medium, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, the use of memory materials has been at the core of the electronics industry such as computers and related equipment and AV equipment such as video disks.
The development of the material is also being actively promoted. The performance required for the memory material varies depending on the application, but in general, (1) high density and large recording capacity (2) fast response time for recording and reproduction (3) low power consumption (4) productivity Are high and prices are low. Until now, semiconductor memories and magnetic memories using magnetic materials and semiconductors as the main material were mainly used.However, with the remarkable progress of laser technology in recent years, inexpensive optical memories using organic thin films such as organic dyes and photopolymers High-density recording media have appeared.

On the other hand, recently, a scanning tunneling microscope (hereinafter abbreviated as STM) capable of directly observing the electronic structure of surface atoms of a conductor has been developed [G. Binning et a
l. Phys. Rev .. Lett. , 49, 57 (1
982)], which makes it possible to measure a real space image with a high resolution regardless of whether it is single crystal or amorphous, and has the advantage that it can be observed at low power without damaging the sample by electric current. It operates and can be used for various materials, so that a wide range of applications can be expected. The STM utilizes the fact that a tunnel current flows when a voltage is applied between a metal probe and a conductive material to approach a distance of about 1 nm. This current is very sensitive to changes in the distance between them.
By scanning the probe so as to keep the tunnel current constant, it is possible to read various kinds of information on all electron clouds in the real space. At this time, the resolution in the in-plane direction is 0.1 nm.
It is about. Therefore, if the principle of the STM is applied, it becomes possible to perform ultra-high-density recording / reproduction sufficiently in the atomic order (sub-nanometer). For example, JP-A-61-8
In the recording / reproducing apparatus disclosed in Japanese Patent No. 0536, atomic particles adsorbed on the medium surface are removed by an electron beam or the like, writing is performed, and this data is reproduced by STM. As the recording layer, 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 a chalcogen compound, is used for recording / recording.
A method of performing reproduction by STM has been proposed (JP-A-63
161552, JP-A-63-161553). According to this method, the recording bit size is set to 10 nm.
If this is the case, large-capacity recording and reproduction as high as 10 12 bits / cm 2 can be achieved.

FIG. 8 shows a configuration example of an information processing apparatus to which the STM technology is applied. Hereinafter, description will be made with reference to the drawings. 11
Denotes a substrate, 12 denotes a metal electrode layer, and 13 denotes a recording layer. 2
01 is an XY stage, 202 is a probe, 203 is a support for the probe, 204 is a linear actuator for driving the probe in the Z direction, and 207 is a pulse voltage circuit. An amplifier 301 detects a tunnel current flowing from the probe 202 to the electrode layer 12 via the recording layer 13. 302 is a logarithmic compressor for converting a change in tunnel current into a value proportional to the gap distance between the probe 202 and the recording layer 13, and 303 is a recording layer 1
3 is a low-pass filter for extracting surface unevenness components. An error amplifier 304 detects an error between the reference voltage V ref and the output of the low-pass filter 303.
Is a driver for driving the Z-axis linear actuator 204. A drive circuit 306 controls the position of the XY stage 201. 307 is a high-pass filter for separating data components.

FIG. 9 shows a cross section of a conventional recording medium and a probe 2.
02 is shown. Reference numeral 401 denotes data bits recorded on the recording layer 13, and 402 denotes crystal grains formed when the electrode layer 12 is formed on the substrate 11. The size of the crystal grains 402 is
When a normal vacuum deposition method, a sputtering method, or the like is used as a method for forming the electrode layer 12, the thickness is about 30 to 50 nm. The gap between the probe 202 and the recording layer 13 can be kept constant by the circuit configuration shown in FIG. That is, the probe 202 and the recording layer 13
Between the logarithmic compressor 30 and the
2. After passing through the low-pass filter 303, this value is compared with a reference voltage, and the probe 20 is set so that the comparison value approaches zero.
The gap between the probe 202 and the recording layer 13 can be made constant by controlling the Z-axis linear actuator 204 that supports the actuator 2.

Further, by driving the XY stage 201, the probe 202 traces the surface of the recording medium, and separates the high frequency components of the signal at point a, thereby forming the recording layer 13
Data can be detected. FIG. 10 shows the signal intensity spectrum with respect to the frequency of the signal at point a at this time. The signal of the frequency component equal to or less than f0 is due to the gradual undulation of the medium due to the warpage or distortion of the substrate 11 or the like. The signal centered at f1 is due to the irregularities on the surface of the recording layer 13, and is mainly due to the crystal grains 402 generated when the electrode material is formed. f2 is a carrier component of recording data, and 403 is a data signal band. f3 is a signal component generated from the arrangement of atoms and molecules in the recording layer 13.

[0007]

When the recording medium shown in the conventional example is used, there are the following problems. To perform high-density recording utilizing the high resolution characteristic of the STM, the data signal band 403 must be placed between f1 and f3. In this case, a high-pass filter 307 having a cutoff frequency fc is used to separate data components. However, the base of the signal component of f1 overlaps with the data signal band 403. This is because the signal component of f1 is caused by the crystal grains 402 of the electrode layer 12, and
This is because the data recording size and the bit interval are close to 1 to 10 nm for the crystal grains 402 of 30 to 50 nm. For this reason, the S / N ratio of data reproduction is reduced, and the error rate of read data is significantly increased.

Accordingly, the present invention has been made to solve the above-mentioned problems in the prior art, and to provide an electrode substrate and a recording medium having a high S / N ratio and enabling high-speed reproduction, and a method of manufacturing the same. The purpose is.

[0009]

In order to solve the above-mentioned problems, the present invention is characterized in that an electrode substrate, a recording medium and a method of manufacturing them are constituted as follows.
That is, the electrode substrate of the present invention is an electrode substrate having a metal electrode layer having a smooth surface, and the electrode substrate has a lower coefficient of thermal expansion than the metal electrode layer in a lower layer direction with the metal electrode layer as an upper layer on the substrate. A low thermal expansion layer, a high thermal conductive layer having higher thermal conductivity than the low thermal expansion layer, a multi-layer metal layer having a metal adhesion layer formed thereon, and the surface of the metal electrode layer has a smooth surface on a substrate having a smooth surface. A smooth surface is formed by peeling the substrate from the metal electrode layer formed on the substrate and transferring a smooth substrate surface shape of the substrate to the metal electrode surface. Further, the electrode substrate of the present invention,
The metal electrode layer is made of a noble metal. Further, in the electrode substrate of the present invention, the noble metal is Au,
It is characterized by being any one of Pt, Pd, Ir, Rh, and Ru, or an alloy containing them. Further, in the electrode substrate of the present invention, the high thermal conductive layer may be made of Au, Ag, C
u, Al or an alloy thereof.
Further, in the electrode substrate of the present invention, the low thermal expansion layer may include W, T
a, Mo, Cr, Ti, Zr or an alloy or a compound thereof. Further, in the electrode substrate of the present invention, the adhesion layer may be made of W, Ta, Mo, Cr, T
i, Zr, an alloy thereof, or a compound thereof. Further, the electrode substrate of the present invention is characterized in that the multilayer metal layers are arranged in an island shape on the substrate. Further, the electrode substrate of the present invention is characterized in that the metal electrode layer has a smooth surface of 1 nm or less and a smooth surface of 1 μm square or more. Further, the recording medium of the present invention,
A recording medium having a recording layer formed on a metal electrode layer, wherein the recording medium is formed on the electrode substrate according to any one of the above-described aspects of the invention. Further, the recording medium of the present invention is characterized in that the surface of the recording layer has a smooth surface of 1 nm or less and 1 μm square or more. Also,
The method for manufacturing an electrode substrate according to the present invention is a method for manufacturing an electrode substrate having a metal electrode layer having a smooth surface. 1. a step of forming a metal electrode layer on a first substrate having a smooth surface; 2. forming a low thermal expansion layer having a lower coefficient of thermal expansion than the metal electrode layer on the metal electrode layer; 3. forming an adhesion layer made of metal on the second substrate; Either on the adhesion layer or on the low thermal expansion layer,
Or a step of forming a metal electrode layer and a high thermal conductive layer made of a metal having higher thermal conductivity than the low thermal expansion layer on both layers; Either the above-mentioned adhesion layer or the above-mentioned low-thermal-expansion layer, or the high-thermal-conductivity layer made of metal formed on both layers and the high-thermal-conductivity layer made of metal or the surface of another layer were brought into contact with each other. Thereafter, a step of performing a pressure treatment; Separating the first substrate from the metal electrode layer and transferring the smooth shape of the first substrate to the metal electrode surface. Further, in the method for manufacturing an electrode substrate according to the present invention, the metal electrode layer is made of a noble metal. Further, in the method for manufacturing an electrode substrate according to the present invention, the noble metal is preferably Au, Pt,
It is characterized by being one of Pd, Ir, Rh, and Ru, or an alloy containing them. Further, in the method for manufacturing an electrode substrate according to the present invention, the low thermal expansion layer may be formed of W, Ta,
It is characterized by being Mo, Cr, Ti, Zr or an alloy or a compound thereof. Further, in the method for producing an electrode substrate according to the present invention, the high thermal conductive layer made of
u, Ag, Cu, Al or an alloy thereof. Further, the method for manufacturing an electrode substrate according to the present invention is characterized in that the adhesion layer made of the metal is a laminated film of two or more layers made of a noble metal layer and a base metal layer. Further, the method for manufacturing an electrode substrate according to the present invention is characterized in that, in the manufacturing method, a step of processing a layer formed on the first substrate into an island shape is provided. In the method for manufacturing an electrode substrate according to the present invention, in the step of performing the pressure treatment, a heat treatment is performed after the pressure treatment. Also,
The method of manufacturing an electrode substrate according to the present invention is characterized in that in the step of performing the pressure treatment, the pressure treatment and the heat treatment are performed simultaneously. Further, the method for manufacturing an electrode substrate according to the present invention is characterized in that the surface of the metal electrode layer has a smooth surface of 1 nm or less and 1 μm square or more. Also,
The method for manufacturing a recording medium of the present invention is a method for manufacturing a recording medium in which a recording layer is formed on a metal electrode surface of an electrode substrate,
The recording layer is formed on the metal electrode surface of the electrode substrate formed by any one of the electrode substrate manufacturing methods of the present invention described above. In the method for manufacturing an electrode substrate according to the present invention, the recording layer is an organic compound formed by a Langmuir-Blodgett method. Further, the method of manufacturing an electrode substrate of the present invention,
The recording layer is characterized in that the surface unevenness has a smooth surface of 1 nm or less and 1 μm square or more.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention has the above-described structure,
An electrode substrate having a smooth surface, a recording medium, and a method for manufacturing the same can be realized, and the function of an information processing device to which the STM principle is applied can be fully utilized. Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 shows a sectional view of an electrode substrate and a recording medium of the present invention. 10
1 is a substrate, 102 is an adhesion layer, 103 is a high thermal conductive layer, 10
4 Low thermal expansion layer, 105 is a metal electrode layer, 106 is a recording layer. FIG. 2 is a sectional view showing each step of the method for manufacturing a recording medium according to the present invention. In FIG. 2A, first, a first substrate 109 is prepared. This substrate is required to have a smooth surface having a surface unevenness of 1 nm or less, preferably 1 μm square or more.

The surface roughness can be measured by an atomic force microscope (hereinafter, referred to as AFM). A
The use of FM makes it possible to measure the surface shape of a sample with an atomic order resolution regardless of the presence or absence of conductivity of the sample. The present inventor evaluated the surface of various materials using AFM, and found that the following materials were suitable for the first substrate 109 in the present invention. (1) Cleavage surface of crystal: The cleavage surface of the crystal can easily obtain an extremely smooth surface.
O, TiC, Si, mica, HOPG and the like. (2) molten glass surface: for example, float glass,
# 7059 fusion fused quartz. (3) Others: An extremely smooth surface can be obtained even with a Si thermal oxide film on a sufficiently smooth Si wafer surface.

Next, as shown in FIG. 2B, a metal electrode layer 105 is formed on the first substrate 109. The metal electrode layer 105 has high conductivity, and further has a first
A material having poor adhesion to the substrate 109 is preferable. For example, a noble metal such as Pt, Pd, Ir, Rh, Ru, and Au, an alloy containing them, and a stacked film of them are included. As a method of forming a thin film using such a material, a conventionally known thin film forming technique is sufficient. Next, FIG.
-As shown in (c), the low thermal expansion layer 104 is formed on the metal electrode layer 105. Materials include W, Ta, Mo,
Cr, Ti, Zr or an alloy thereof or a compound thereof is preferably used. Next, as shown in FIG. 2D, the high thermal conductive layer 103 is formed on the low thermal expansion layer 104. As the material, Au, Ag, Cu, Al or an alloy thereof is preferably used.

Next, as shown in FIG. 2E, an adhesion layer 102 also serving as an electrode wiring is formed on the second substrate 101. As a material of the adhesion layer 102, any metal may be used as long as the second substrate 101 and the high thermal conductive layer 103 can be bonded to each other. For example, Ti, Cr, W, Ta, or the like can be used. Subsequently, as shown in FIG. 2F, the high thermal conductive layer 103 is formed on the adhesion layer 102. Next, FIG.
-As shown in (g) and (h), the surfaces of the first substrate and the second substrate on which the metal is formed are brought into contact with each other, and pressure is applied. The pressure at this time is not particularly limited, but several kg to several tens kg / cm.
^{About 2} . When heat treatment is used, bonding can be performed at a lower pressure. The temperature in this case depends on the pressure, but is usually 1000 ° C. or less. The heat treatment may be performed separately from the pressure treatment, but is preferably performed simultaneously.

Next, as shown in FIG. 2I, the electrode substrate 107 can be formed by peeling the first substrate 109 from the interface between the first substrate 109 and the metal electrode layer 105. The smoothness of the metal electrode layer surface 105 of the electrode substrate 107 is equal to the smoothness of the first substrate 109, and the surface unevenness is 1 nm.
It has the following smooth surface of 1 μm square or more. Next, FIG.
-As shown in (j), the recording layer 1 on the metal electrode layer 105
By forming 06, the recording medium 108 is obtained.
As disclosed in JP-A-63-161552, the recording layer 106 is made of a material having a memory switching phenomenon (electric memory effect) in current-voltage characteristics, for example, a group having a π electron level and a σ electron. An organic monomolecular film of a molecule having a group having only a level alone or its cumulative film is represented by L
It can be formed on the metal electrode layer 105 by a B (Langmuir-Blodgett) method. Since the organic monomolecular film of these molecules or the cumulative film formed by the LB method faithfully reproduces the unevenness of the substrate, the recording layer should have the same smoothness as the metal electrode layer surface 105. Can be.

Further, a recording medium in which a multilayer metal layer on a substrate is formed in an island shape can be manufactured. FIG. 3 is a sectional view, and FIG. 4 is a top view. Each island may be formed on a metal surface as shown in FIG. 4A, or may be connected to each other by an electrode wiring 110 as shown in FIG. FIG. 5 shows the manufacturing method of FIG. 4A, and FIG. 6 shows the manufacturing method of FIG. First, the metal electrode layer 10 is formed on the first substrate 109.
5. The low thermal expansion layer 104 and the high thermal conductive layer 103 are formed (FIGS. 5D and 6D). Next, as shown in FIGS. 5E and 6E, a multilayer metal layer including the metal electrode layer 105, the low thermal expansion layer 104, and the high thermal conductive layer 103 is processed into an island shape 110. Next, the adhesion layer 102 and the high thermal conductive layer 103 are formed on the second substrate 101 (FIGS. 5F and 6F). Here, when each island 110 is connected by an electrode wiring, the second
The adhesion layer 102 and the high thermal conductive layer 103 on the substrate 101 are processed into a wiring shape (FIG. 6-g). Hereinafter, after positioning both substrates in the same manner as in FIG. 2, bonding is performed by applying pressure. At this time or after this, heat treatment may be performed. Next, FIG.
-H, as shown in FIG. 6-i, the metal electrode layer 105 and the first
The electrode substrate 107 is obtained by peeling off at the interface of the substrate 109.
Further, a recording medium 108 is obtained by forming a recording layer 106 on the metal electrode layer 105.

FIGS. 7A and 7B are cross-sectional views of the medium and the probe and the frequency spectrum of the signal at point a when the information processing apparatus shown in FIG. 8 is used as the recording medium 108 according to the present invention. The signal of the frequency component of f0 or less is warped of the substrate 101,
This is due to the gradual undulation of the medium due to distortion or the like. f
2 is a carrier component of the recording data, and 403 is a data signal band. f3 is a signal component generated from the arrangement of atoms and molecules in the recording layer 106. The signal centered at f1 is a signal in which slight irregularities of the first substrate 109 are transferred to the surface of the metal electrode layer 105, and the irregularities are formed smaller than the data recording signal. The change in this unevenness is 1 nm or less in recording and reproduction using STM.

As described above, the following effects can be obtained. First, the effects obtained by obtaining a recording medium having high smoothness include: (1) The signal component f1 due to the unevenness of the recording layer surface does not overlap with the data signal band, and the S / N ratio due to the spread of the spectrum of f1 is reduced. There is no decline. That is, the data error rate can be reduced. (2) Since there is no unevenness on the surface of the recording layer, the displacement of the Z-axis of the probe during XY scanning while keeping the gap between the surface of the recording layer and the probe constant is small. For this reason, the XY stage can be driven very quickly. The effect of the recording layer formed on the metal laminated film including the metal electrode layer, the low thermal expansion layer, the high thermal conductive layer, and the adhesion layer is as follows. By forming on the expandable metal layer, expansion of the metal electrode layer due to heat can be suppressed as much as possible. (2) The heat generated between the probe and the medium at the time of recording / reproducing can be quickly diffused by the high thermal conductive layer, and the temperature rise and thermal expansion can be suppressed. (3) By arranging the recording medium surface in an island shape, the heat radiation effect can be greatly increased. (4) Since the diffusion of the high thermal conductive layer into the metal electrode layer can be prevented by the low thermal expansion layer, the smoothness of the metal electrode layer due to the diffusion of the high thermal conductive layer into the metal electrode layer can be suppressed. The effect of suppressing the thermal expansion of the recording medium is extremely important and indispensable when recording / reproducing information at the nm level. Further, the method of manufacturing an electrode substrate has the following operational effects. (1) Since a metal is used as the bonding layer, an electrode substrate having high heat resistance can be formed. Thus, a recording medium layer or the like can be formed on the electrode substrate at a higher temperature than before while maintaining smoothness. (2) Since the thin film metal layer is used as the bonding layer, the adhesive does not protrude to a portion other than the desired bonding surface as compared with the case where a coating type organic bonding layer is used. (3) Since the thin film metal layer is used as the bonding layer, the height of the metal electrode layer surface from the substrate surface holding the metal electrode layer can be controlled, and the height of the substrate surface can be reduced as compared with the case where a coating type organic adhesive layer is used. Parallelization of the electrode layer surface can be easily performed. (4) A smooth metal electrode layer can be formed on any substrate material as long as a bonding layer can be formed via a metal layer. (5) When the metal electrode layer is processed into an island shape, its surface is not exposed to a resist or its peeling liquid, etc.
Transfer and formation can be performed while maintaining a clean surface.

[0018]

EXAMPLES The method for smoothing the surface of a gold crystal according to the present invention will be described below in detail with reference to examples. Embodiment 1 Embodiment 1 of the present invention will be described with reference to FIG. First, as shown in FIG. 2A, a first substrate 109 having a smooth surface was prepared. Thermal oxide film 1 on substrate
A Si wafer having a thickness of 00 nm was used. continue,
As shown in FIG. 2B, an alloy layer of Pt and Au is formed on the first substrate 109 by a sputtering method, and the metal electrode layer 1 is formed.
05 was formed. The electrode layer 105 has a deposition rate of 0.1 n.
The measurement was performed under the conditions of m / sec and a film thickness of 60 nm. Subsequently, as shown in FIG. 2C, W was deposited as the low thermal expansion layer 104 on the metal electrode layer 105 at a deposition rate of 0.5 nm / sec and a film thickness of 500 nm. Next, as shown in FIG. 2D, Au as a high thermal conductive layer 103 is formed on the low thermal expansion layer 104.
Was formed to a thickness of 100 nm.

Next, as shown in FIG. 2E, a Cr film having a thickness of 5 nm is formed as an adhesion layer 102 on a second substrate 101 made of a Si wafer, and further as shown in FIG. As described above, on the adhesion layer 102, A
u was formed to a thickness of 100 nm. Next, FIG.
As shown in (h), after the joining surfaces of the first substrate 109 and the second substrate 101 were aligned, pressure was applied so that both substrates were pressed against each other. The pressure was 5 kg / cm ² . next,
Under pressure, both substrates were heated to 250 ° C. and held for 60 seconds, then cooled to room temperature. Subsequently, as shown in FIG. 2I, the first substrate 109 is peeled off from the interface with the metal electrode layer 105 to form an electrode substrate 107 having a smooth surface.
I got When the electrode surface of the electrode substrate 107 thus obtained was observed by STM, the surface irregularity was 1 nm or less in a square of 1 μm.

Next, as shown in FIG. 2J, the recording layer 1 made of a polyimide LB film is formed on the surface of the metal electrode layer 105.
06 to form a recording medium 108. Polyimide L
The B film was formed by the method disclosed in JP-A-63-161552. As a material, a polyamic acid octadecylamine salt was used. Six monomolecular films were formed on the electrode surface, followed by baking at 350 ° C. for 20 minutes to obtain a recording layer made of polyimide. When the surface of the recording layer thus obtained was observed by AFM, the surface unevenness was 1 nm or less in a 1 μm square.

Next, a recording / reproducing experiment was performed. Probe 202
Used was made of Pt / Rh. The distance (Z) of the probe 202 is finely controlled by a piezoelectric element so as to keep the current constant by controlling the distance (Z) to the surface of the recording layer 106. Further, the linear actuators 204, 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 recording medium 108 described above was placed on the XY stage. Next, the probe 202 and the electrode layer 1 of the recording medium
A voltage of +1.5 V was applied during 05, and the distance Z between the probe 202 and the surface of the recording layer 106 was adjusted while monitoring the current. At this time, the current Ip for controlling the distance Z between the probe 202 and the surface of the recording layer 106 is set to 10 ⁻¹⁰ ≧ Ip ≧ 10 ⁻¹¹
It was set to become. Next, the probe 202 is moved to the recording layer 106.
While scanning the upper part, information recording was continuously performed at a pitch of 20 nm. For recording, a rectangular pulse voltage was applied with the probe being + and the electrode layer being-. Then, when the recorded bit was scanned again, it was confirmed that a current of about 10 nA flowed on the bit. The error rate of the read data was examined at a constant reading speed while performing such scanning continuously for a long time, and the error rate was greatly reduced due to the smoothness of the substrate, the heat dissipation during recording and reproduction, and the effect of suppressing thermal expansion. did it.

Embodiment 2 Embodiment 2 of the present invention will be described with reference to FIG. First, as shown in FIG.
Float glass with sufficient smoothness was used as the first substrate 109. Subsequently, as shown in FIG.
Au and Pd were simultaneously formed on the substrate 09 by a sputter deposition method to form a metal electrode layer 105. The metal electrode layer 105
Was performed under the conditions of a deposition rate of 0.2 nm / sec and a film thickness of 100 nm. Subsequently, as shown in FIG. 5C, Ta was deposited as the low thermal expansion layer 104 on the metal electrode layer 105 at a deposition rate of 0.4 nm / sec and a film thickness of 600 nm. Next, as shown in FIG. 5D, Al was formed on the low thermal expansion layer 104 as the high thermal conductive layer 103 to a thickness of 100 nm. Next, as shown in FIG.
9 by dry etching of the metal laminated film on
Processed to.

Next, as shown in FIG. 5F, an Al film having a thickness of 100 nm was formed as a high thermal conductive layer 103 serving also as an adhesion layer 102 on a second substrate 101 made of a Si wafer. Next, as shown in FIG.
After the joining surfaces of the substrate 9 and the second substrate 101 were aligned, pressure was applied so that both substrates were pressed against each other. The pressure is 6kg / cm
^{And 2} . Next, both substrates were heated to 450 ° C. in a pressurized state, held for 2 minutes, and then cooled to room temperature. Subsequently, as shown in FIG. 2H, the first substrate 109 was peeled off from the interface with the metal electrode layer 105 to obtain an electrode substrate 107 having a smooth surface. When the electrode surface of the electrode substrate 107 thus obtained was observed by STM, it was 1 μm
The surface unevenness was 1 nm or less in a square.

Next, as in the first embodiment, the metal electrode layer 10
A recording layer 106 made of a polyimide LB film was formed on the surface of No. 5 to produce a recording medium 108 (FIG. 5- (i)). When the surface of the recording layer thus obtained was observed by AFM, the surface unevenness was 1 nm or less in a 1 μm square. Next, as in the first embodiment, the error rate of the read data was examined at a constant reading speed while scanning was continuously performed for a long time. As a result, the smoothness of the substrate, heat radiation during recording and reproduction, and thermal expansion were measured. The suppression effect resulted in a significant reduction.

Embodiment 3 Embodiment 3 of the present invention will be described with reference to FIG. First, as shown in FIG.
Float glass with sufficient smoothness was used as the first substrate 109. Subsequently, as shown in FIG.
Pt was formed on the substrate 09 by a sputter deposition method to form a metal electrode layer 105. The metal electrode layer 105 was formed under conditions of a deposition rate of 0.2 nm / sec and a thickness of 400 nm.
Subsequently, as shown in FIG.
Ta is deposited thereon as a low thermal expansion layer 104 at a deposition rate of 0.4 nm.
/ Sec and a film thickness of 600 nm. Next, FIG.
As shown in (d), Au was formed to a thickness of 100 nm on the low thermal expansion layer 104 as the high thermal conductive layer 103. Next, as shown in FIG. 6E, the metal laminated film on the first substrate 109 was processed into an island shape 110 by dry etching.

Next, as shown in FIG. 6F, Cr is formed to a thickness of 5 nm as an adhesion layer 102 on a second substrate 101 made of a Si wafer, and a high thermal conductive layer 103 is formed on the adhesion layer 102. Au was deposited to a thickness of 100 nm. Next, as shown in FIG. 6G, the adhesive layer 102 and the high thermal conductive layer 103 were patterned to form the electrode wiring 111. Next, as shown in FIG.
After the joining surfaces of the substrate 09 and the second substrate 101 were aligned, pressure was applied so that both substrates were pressed against each other. Pressure is 3kg / c
It was m ^2. Next, both substrates were heated to 200 ° C. and kept for 10 seconds while being pressed, and then cooled to room temperature. Subsequently, as shown in FIG. 6- (i), the first substrate 109 was peeled off from the interface with the metal electrode layer 105 to obtain an electrode substrate 107 having a smooth surface. When the electrode surface of the electrode substrate 107 thus obtained was observed by STM,
The surface unevenness was 1 nm or less at 1 μm square.

Next, as in the first embodiment, the metal electrode layer 10
The recording layer 106 made of a polyimide LB film was formed on the surface of the No. 5 to prepare a recording medium 108 (FIG. 6- (j)). When the surface of the recording layer thus obtained was observed by AFM, the surface unevenness was 1 nm or less in a 1 μm square. Next, as in the first embodiment, the error rate of the read data was examined at a constant reading speed while scanning was continuously performed for a long time. As a result, the smoothness of the substrate, heat radiation during recording and reproduction, and thermal expansion were measured. The suppression effect resulted in a significant reduction.

[0028]

As described above, according to the recording medium of the present invention and the method of manufacturing the same, the signal component f1 due to the unevenness of the recording layer surface and the data signal band do not overlap.
There is no decrease in S / N due to the spread of the spectrum of 1.
The data error rate can be reduced. Further, according to the recording medium and the method for manufacturing the same of the present invention, since there is no irregularity on the surface of the recording layer, the displacement of the Z-axis of the probe when performing XY scanning while keeping the gap between the surface of the recording layer and the probe constant. Can be reduced, and the XY stage can be driven very quickly. Further, since the recording medium of the present invention is formed on a multilayer metal layer composed of a lower thermal expansion layer, a high thermal conductive layer, and a metal adhesion layer with the metal electrode layer as the upper layer, the metal electrode layer having high smoothness Can be formed on a metal layer having low thermal expansion, and expansion of the metal electrode layer due to heat can be suppressed as much as possible. Further, in the present invention, with this configuration, the heat generated between the probe and the medium during recording and reproduction can be quickly diffused by the high thermal conductive layer, and the temperature rise and thermal expansion can be suppressed.
Further, in the recording medium of the present invention, the heat radiation effect can be greatly enhanced by arranging the recording medium surface in an island shape. Further, in the recording medium of the present invention, since the low thermal expansion layer can prevent the high thermal conductive layer from diffusing into the metal electrode layer, the smoothness of the metal electrode layer due to the high thermal conductive layer diffusing into the metal electrode layer is suppressed. be able to. According to the electrode substrate and the method of manufacturing the same of the present invention, since a metal is used as the bonding layer, it is possible to form an electrode substrate having high heat resistance, and at a higher temperature than before, such as a recording medium layer while maintaining smoothness. Can be formed on the electrode substrate. Further, according to the electrode substrate and the method of manufacturing the same of the present invention, since the thin film metal layer is used as the bonding layer,
Compared to the case of using a conventional coating type organic adhesive layer,
It is possible to prevent the adhesive from protruding to a portion other than the desired adhesive surface. Further, according to the electrode substrate and the method of manufacturing the same of the present invention, since the thin film metal layer is used as the bonding layer, the metal from the substrate surface holding the metal electrode layer can be compared with a case where a coating type organic adhesive layer is used. Control of the electrode layer surface height, parallelization of the substrate surface and the electrode layer surface, and the like can be easily performed.
Further, according to the electrode substrate and the method of manufacturing the same of the present invention, a smooth metal electrode layer can be formed on any substrate material as long as the material can form an adhesive layer via a metal layer.

[Brief description of the drawings]

FIG. 1 is a diagram showing an electrode substrate and a recording medium of the present invention.

FIG. 2 is a diagram showing a manufacturing method of the present invention.

FIG. 3 is a sectional view of an electrode substrate and a recording medium of the present invention.

4 is a top view of FIG. 3; FIG. 4 (A) shows the configuration of an electrode substrate and a recording medium in which each island is formed on a metal surface; FIG. FIG. 3 is a diagram illustrating a form of an electrode substrate and a recording medium connected by wiring.

FIG. 5 is a diagram showing a manufacturing method of the present invention.

FIG. 6 is a view showing a manufacturing method of the present invention.

7A is a schematic sectional view of a recording medium, FIG.
(B) is a diagram showing a diagram of a frequency spectrum of a reproduction signal of the present invention.

FIG. 8 is a diagram showing an information processing apparatus to which STM is applied.

FIG. 9 is a sectional view of a conventional recording medium.

FIG. 10 is a diagram showing a diagram of a frequency spectrum of a conventional reproduction signal.

[Explanation of symbols]

 11: substrate 12: metal electrode layer 13: recording layer 101: second substrate 102: adhesion layer 103: high thermal conductive layer 104: low thermal expansion layer 105: metal electrode layer 106: recording layer 107: electrode substrate 108: recording medium 109: first substrate 110: island 111: electrode wiring 201: xy stage 202: probe 203: probe support 204, 205, 206: linear actuator 207: pulse voltage circuit 301: amplifier 302: logarithmic compressor 303 : Low-pass filter 304: error amplifier 305: driver 306: drive circuit 307: high-pass filter 401: data bit 402: crystal grain 403: data signal band

Claims (23)

[Claims] An electrode substrate having a metal electrode layer having a smooth surface, wherein the electrode substrate has a lower coefficient of thermal expansion in a lower layer direction than the metal electrode layer with the metal electrode layer as an upper layer on the substrate. A high thermal conductive layer having a higher thermal conductivity than the low thermal expansion layer, a multi-layer metal layer on which an adhesion layer made of metal was formed, and the surface of the metal electrode layer was formed on a substrate having a smooth surface. An electrode substrate having a smooth surface formed by peeling the substrate from a metal electrode layer and transferring a smooth substrate surface shape of the substrate to the metal electrode surface. 2. The electrode substrate according to claim 1, wherein said metal electrode layer is a noble metal. 3. The method according to claim 1, wherein the noble metal is Au, Pt, Pd, Ir,
3. The electrode substrate according to claim 2, wherein the electrode substrate is one of Rh and Ru or an alloy containing them. 4. The high thermal conductive layer is made of Au, Ag, Cu, A
The electrode substrate according to any one of claims 1 to 3, wherein the electrode substrate is l or an alloy thereof. 5. The low thermal expansion layer is made of W, Ta, Mo, C
The electrode substrate according to any one of claims 1 to 4, wherein the electrode substrate is r, Ti, Zr, an alloy thereof, or a compound thereof. 6. The adhesion layer is made of W, Ta, Mo, Cr, T
The electrode substrate according to any one of claims 1 to 5, wherein the electrode substrate is i, Zr, an alloy thereof, or a compound thereof. 7. The electrode substrate according to claim 1, wherein the multilayer metal layers are arranged in an island shape on the substrate. 8. The metal electrode layer has a surface unevenness of 1n.
The electrode substrate according to any one of claims 1 to 7, wherein the electrode substrate has a smooth surface of not more than m and not less than 1 µm square. 9. A recording medium having a recording layer formed on a metal electrode layer, wherein the recording layer is formed on the electrode substrate according to any one of claims 1 to 7. A recording medium characterized by the above-mentioned. 10. The recording layer has a surface unevenness of 1 nm.
The recording medium according to claim 9, wherein the recording medium has the following smooth surface of 1 μm square or more. 11. A method for manufacturing an electrode substrate having a metal electrode layer having a smooth surface, comprising: 1. a step of forming a metal electrode layer on a first substrate having a smooth surface; 2. forming a low thermal expansion layer having a lower coefficient of thermal expansion than the metal electrode layer on the metal electrode layer; 3. forming an adhesion layer made of metal on the second substrate; Either on the adhesion layer or on the low thermal expansion layer,
Or a step of forming a metal electrode layer and a high thermal conductive layer made of a metal having higher thermal conductivity than the low thermal expansion layer on both layers; Either one of the adhesion layer or the low thermal expansion layer, or the high thermal conductive layer made of metal and the high thermal conductive layer made of metal formed on both layers were brought into contact with each other. Thereafter, a step of performing a pressure treatment; Separating the first substrate from the metal electrode layer and transferring a smooth shape of the first substrate to the surface of the metal electrode. 12. The method according to claim 11, wherein said metal electrode layer is a noble metal. 13. The method according to claim 13, wherein the noble metal is Au, Pt, Pd, I
13. The method for manufacturing an electrode substrate according to claim 12, wherein the electrode substrate is any one of r, Rh, and Ru, or an alloy containing them. 14. The low thermal expansion layer is made of W, Ta, Mo, C
14. Any one of claims 11 to 13, characterized in that it is r, Ti, Zr or an alloy or a compound thereof.
Item 13. The method for producing an electrode substrate according to item 1. 15. The high thermal conductive layer made of a metal, wherein Au,
The method for manufacturing an electrode substrate according to any one of claims 11 to 14, wherein the electrode substrate is made of Ag, Cu, Al, or an alloy thereof. 16. The electrode substrate according to claim 11, wherein the adhesion layer made of a metal is a laminated film of two or more layers made of a noble metal layer and a base metal layer. Manufacturing method. 17. The electrode substrate according to claim 11, wherein said manufacturing method includes a step of processing a layer formed on said first substrate into an island shape. Manufacturing method. 18. The method according to claim 11, wherein in the step of performing the pressure treatment, a heat treatment is performed after the pressure treatment.
A method for manufacturing an electrode substrate according to claim 17. 19. The method for manufacturing an electrode substrate according to claim 11, wherein in the step of performing the pressure treatment, the pressure treatment and the heat treatment are performed simultaneously. 20. The electrode substrate according to claim 11, wherein the metal electrode layer has a smooth surface having a surface roughness of 1 nm or less and a square of 1 μm or more. Manufacturing method. 21. A method for manufacturing a recording medium for forming a recording layer on a surface of a metal electrode of an electrode substrate, wherein the recording medium is formed by the method for manufacturing an electrode substrate according to any one of claims 11 to 20. Forming the recording layer on the metal electrode surface of the electrode substrate. 22. The method according to claim 21, wherein the recording layer is an organic compound formed by a Langmuir-Blodgett method. 23. The recording layer, wherein the surface unevenness of the layer is 1 nm.
23. The method for manufacturing a recording medium according to claim 21, wherein the following smooth surface has a square of 1 μm or more.