JPH03116001A - Production of grating - Google Patents

Abstract

PURPOSE:To easily and accurately obtain grating patterns of a fine pitch by bringing magnetic colloidal fluid having a sufficiently small particle size of colloidal particles into contact with a magnetic recording medium to generate patterns, laminating and forming a metallic film thereon, then laminating and fixing a transparent resin layer and peeling the resin layer together with the metallic film. CONSTITUTION:The magnetization patterns complying with the grating patterns are formed when the grating patterns are written on the magnetic recording medium 2 by a magnetic head. The magnetic colloidal fluid consisting of colloidal particles of the particle sizes sufficiently smaller than the magnetization patterns gathers to the boundary parts of magnetic domains when the magnetic colloidal fluid 3 is brought into contact with the surface of this magnetic recording medium so as to be stuck thereon. The patterns of the magnetic colloidal fluid 3 of the same pitch as the pitch of the grating patterns are eventually obtd. After the metallic film 4 is laminated and formed on the patterns of such magnetic colloidal fluid, the transparent resin layer 5 is laminated thereon and is solidified; thereafter, the resin layer 5 is peeled together with the metallic film 4 from the magnetic recording medium 2, by which the reflection type surface relief grating having the desired grating patterns are obtd. The surface relief gratings of the reflection type and transmission type are easily obtd. at a low cost in this way.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a diffraction grating applied to a spatial light modulation element, etc.
The present invention relates to a grating manufacturing method for manufacturing a grating pattern applied to linear encoders, rotary encoders, hologram disks for hologram scanners, computer holograms, etc.

[Conventional technology]

A grating pattern with a certain periodic structure used in linear encoders, rotary encoders, etc.

As methods for producing irregular lattice patterns such as computer hologram patterns, methods using lithography and methods using interference exposure technology using laser light are conventionally known.

Here, as a method for producing a grating using a lithography method, for example, it is performed as follows.

First, a metal film such as Cr or A1 is formed on a substrate such as glass, and a photoresist is applied thereon. Then, the photoresist layer formed in this way is pattern-exposed through a mask with a desired lattice pattern, and after the photoresist is developed, the metal layer is etched away to form lattice openings, and finally The photoresist is then removed to create a grid.

In addition, in a method that uses interference exposure technology using laser light, instead of using a mask in the lithography method described above,
Using three laser beams such as an Ar laser or a He-Cd laser, the three beams are caused to interfere on the photoresist, and the photoresist layer is pattern-exposed by the periodic interference fringes. Then, the steps of development, etching, and removal of the photoresist are performed in order to produce a grid.

[Problem to be solved by the invention]

By the way, among the above-mentioned grating manufacturing methods, in the grating manufacturing method using lithography, pattern exposure is performed using light, so the pattern becomes finer and has a pitch of, for example, 0.3~.
When the diameter is less than 0.4 μm, one diffraction occurs, making it impossible to perform accurate pattern exposure.Therefore, there is a drawback that a grating having a finer grating pattern than a certain degree cannot be manufactured.

In addition, since the method using interference exposure technology using laser light uses an interference pattern, it is not possible to obtain a grating with a grating pattern other than the pattern that can be generated by interference, and there are limitations due to the wavelength of the light. , it is difficult to fabricate fine pitch.

The present invention has been made in view of the above-mentioned circumstances, and its object is to easily and reliably obtain a desired grating pattern, particularly a grating having an extremely fine pitch. can. The object of the present invention is to provide a new method for producing a grid.

[Means to solve the problem]

In order to achieve the above object, the method for producing a lattice according to the present invention uses a magnetic head to record a desired lattice-shaped magnetization pattern on a magnetic recording medium formed in a stone shape on a substrate, and this magnetization pattern is recorded. A magnetic colloidal fluid in which the colloidal particle size is sufficiently smaller than the magnetization pattern is brought into contact with the magnetic recording medium, and a pattern of the magnetic colloidal fluid corresponding to the magnetization pattern is generated. After forming a metal coating on the fluid pattern, an unsolidified transparent resin layer is laminated, and after the resin layer is solidified, both the metal coating and the resin layer are peeled off from the magnetic recording medium to form a reflective type. It is characterized by producing a surface relief grating.

Further, the above-described method for producing a grating is characterized in that after peeling off the resin layer together with the metal coating from the magnetic recording medium, the metal coating is further removed from the resin layer to produce a transmission type surface relief grating.

Further, in the above-described grating manufacturing method, a bias magnetic field is applied when bringing the magnetic colloid fluid into contact and forming a pattern of the magnetic colloid fluid corresponding to the magnetization pattern.

Here, a glass substrate, a resin substrate, a resin tape, or the like is used as the substrate. The magnetic recording medium formed in the shape of a stone on the substrate may be a magnetized film of Fe2O3 or the like, or may be made of a magnetized film of Fe2O3 etc.
It may also be a perpendicularly magnetized film, such as a -Cr-based film, magnetized uniformly in a predetermined direction in the thickness direction.

Further, the magnetic colloid fluid has colloid particles whose particle size is sufficiently smaller than the magnetization pattern.

For example, a particle size of 100 to 200 people.

As the metal coating, for example, gold is used in the case of a reflective type, and a metal material that can be easily chemically etched is used in the case of a transmission type.

Further, as the transparent resin, a photocurable resin, a thermosetting resin, or the like is used.

Further, as the bias magnetic field applying means, a permanent magnet, an electromagnet, an electromagnetic coil, etc. are used.

[For production]

When a lattice pattern is written on a magnetic recording medium with a magnetic head, a magnetization pattern that follows the lattice pattern is formed by arranging magnetic domains that are magnetized in one plane or in a direction perpendicular to the plane.

A magnetic colloidal fluid made of colloidal particles having a particle size sufficiently smaller than that of the magnetization pattern is applied onto the magnetic recording medium on which the magnetization pattern is formed, for example, 1/1 of the pitch of the above magnetic domain arrangement.
When magnetic colloidal fluid having a particle size of about 10 mm is brought into contact and adhered, the magnetic colloidal fluid gathers at the boundaries of the magnetic domains, so that a pattern of magnetic colloidal fluid having the same pitch as the magnetization pattern is obtained. Therefore, after laminating a metal film on the pattern of this magnetic colloidal fluid, an unsolidified transparent resin layer is laminated, and after the resin layer is solidified, the resin layer together with the metal film is peeled off from the magnetic recording medium. By doing so, a reflective surface relief grating with the desired grating pattern is obtained.

Further, by removing the metal coating of the reflective surface relief grating obtained as described above from the resin layer by etching or the like, a transmission type surface relief grating can be obtained.

Note that when writing a lattice pattern on a magnetic recording medium with a magnetic head, if a perpendicular magnetization film that is uniformly magnetized in a predetermined direction of the film thickness is used as the magnetic recording medium, and a magnetic head for perpendicular magnetization is used, the recording density will be reduced. The maximum is approximately 250Kbits
/1 nch is possible.

That is, it is 1 bitlo, 1 it m, and the magnetic domains can be reversed with a minimum pitch of 0.1 μm. Therefore, a perpendicular magnetization pattern with a minimum pitch of 0.1 μm can be written and formed using a magnetic head.

In addition, when a magnetized film such as Fe2O is used as a magnetic recording medium and magnetized in the in-plane direction, it is not possible to obtain as high a recording density as when using a perpendicularly magnetized film, but it is extremely easy to create a magnetized pattern, and especially It is extremely effective for producing gratings with a pitch of 1 μm or more.

Furthermore, when a magnetic colloidal fluid is brought into contact with a magnetic recording medium and a bias magnetic field is applied when forming a pattern of magnetic colloidal fluid corresponding to a magnetization pattern, the amount of attached magnetic colloidal fluid can be significantly increased. This makes it possible to create lattices with deep grooves.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

FIG. 1 is a process explanatory diagram showing an example of a method for producing a grating according to the present invention, and is an example in which a perpendicularly magnetized film such as a Co--Cr system is used as a magnetic recording medium. here.

When producing a grid for a linear encoder, for example, as shown in FIG. 6, a perpendicular magnetization film with a thickness of about 0.6 μm is formed by sputtering or the like on a base 10 made of a resin tape, a long glass substrate, or the like. A single period magnetization pattern 12 of N5NS .
In addition, when producing a grating for a rotary encoder, as shown in FIG. A magnetic head 1 is attached to the perpendicular magnetization film formed on the substrate.
N5NS with a pitch of about 1 to 5 μm according to 1.
Write a single-period magnetization pattern 12.

FIG. 1 (1) shows N5NS written and recorded on the perpendicular magnetization film 2 formed on the above-mentioned tape-shaped or disc-shaped substrate 1.
. . . schematically shows a single period magnetization pattern, and the left-right direction in the figure corresponds to the longitudinal direction of the tape 10 or the circumferential direction of the disk 14. Here, the perpendicular magnetization film 2
The small arrow in indicates the direction of magnetization, and as a result of writing by the magnetic head 11 for perpendicular magnetization shown in FIGS. 6 and 7, the clock signal 13 input to the magnetic head
1 and 0, an array of minute magnetic domains whose magnetization directions are mutually reversed in the thickness direction of the perpendicular magnetization film 2, that is, a single period magnetization pattern of N5NS due to perpendicular magnetization is formed. Note that the pitch of the magnetic domain arrangement in this magnetization pattern can be reduced to about 0.1 to 0.2 μm.

Next, as shown in FIG. 1(1), a magnetic colloidal fluid having a particle size of about 100 to 200 particles, for example, magnetic When the toner is deposited, as shown in FIG. 1 (2), the Fa magnetic toner gathers in the mounds of the magnetic domains forming the magnetization pattern formed on the perpendicular magnetization film 2, so that it forms a periodic pattern with the same pitch as the magnetization pattern. is formed by the magnetic toner 3.

Next, as shown in Figure 1 (3), a metal such as gold is laminated by vapor deposition or sputtering on the pattern (bitter figure) formed by the magnetic toner 3, and a thickness of 2000 mm is deposited.
A metal coating 4 about the size of a human body is formed.

After forming the metal coating 4, when the diffraction image was taken using an ammeter as a phase grating with only irregularities, a clear Fraunhofer diffraction image could be obtained.

Next, as shown in FIG. 1 (4), after forming the metal coating 4, a photocurable or thermosetting transparent resin 5, such as an optical epoxy resin, is applied or poured onto the metal coating 4. The materials are stacked together and cured by irradiating them with ultraviolet light or applying heat. And transparent resin/1! After solidification of y5, as shown in FIG. 1(5), the metal coating 4 and the resin MS are peeled off from the perpendicular magnetization film 2 to produce a replica of the lattice pattern. At this time, since the metal coating 3 is neatly adhered to the resin layer 5 side, a reflective surface relief grating having an uneven grating pattern is obtained. This reflection type surface relief grating has a magnetization pattern due to perpendicular magnetization copied as a concavo-convex pattern on the surface of the metal coating.It is a surface reflection type grating with the same pitch as the magnetization pattern, and the single diffraction pattern is relatively clear. Obtained. In addition, Fig. 1 (3) to Fig. 1 (
By repeating the step 5), the same reflective surface relief grating can be obtained one after another.

By the way, when producing the above-mentioned reflection type surface relief grating, it is preferable to use gold as the metal coating material, but when producing a transmission type diffraction grating etc., 1. For example, the metal coating 4 is formed using a metal material that can be easily chemically etched instead of gold, and then the first
A transparent resin layer 5 is laminated in the process shown in FIG. 1 (4), and after the resin is solidified, the metal coating 4 and the resin layer 5 are peeled off from the perpendicularly magnetized film 2 as shown in FIG. 1 (5), and further, By removing the metal coating 4 from the resin layer 5 by etching,
A transmission type surface relief grating as shown in FIG. 1(6) can be produced.

Now, as explained above, according to the grating manufacturing method according to the present invention, a diffraction grating consisting of an uneven pattern with a pitch of about 1 to 5 μm can be manufactured very easily, and a diffraction grating can be created not only on a flat surface but also on a curved surface. becomes possible. Therefore, the grid creation method according to the present invention is very effective in creating grid patterns for encoders and the like.

In addition, in the above-mentioned embodiment. Although we have described the case of creating a periodic grating with a pitch of several micrometers, the pitch of the magnetic domain array of the perpendicularly magnetized film 2 can be reduced to about 0.1 to 0.2 micrometers, so it is possible to create a periodic grating with a pitch of several micrometers. It is also possible to create a grid.

Incidentally, reflective or transmissive surface relief gratings can be produced by the manufacturing process shown in FIG. upon attachment.

The problem remains that the amount of magnetic colloidal fluid 3 deposited is small and it is difficult to create a lattice with deep grooves.

Therefore, a method for overcoming this bad luck will be explained based on the embodiment shown in FIG.

FIG. 2 is a diagram showing another embodiment of the step (2) in FIG. When attaching the magnetic colloidal fluid 3, the permanent magnet 7 is brought close to the back side of the substrate, and the magnetic colloidal fluid 3 is attached while applying a bias magnetic field 8. In this way, when the bias magnetic field 8 is applied to the perpendicularly magnetized medium 2 when the magnetic colloidal fluid is attached, the portion (the second In the figure, the magnetic flux density emitted to the outside increases from the upwardly magnetized portion. As a result, the amount of magnetic colloidal fluid 3 that adheres thereto increases significantly compared to when there is no bias magnetic field 8 that causes the magnetic colloidal fluid 3 to adhere there. In the case of the example shown in the second figure, the magnetic coid fluid adheres to the upwardly magnetized portion.

Now, after forming the lattice pattern of the four magnetic colloids 3 as shown in FIG. By performing the transfer onto the resin layer 5, it is possible to produce a reflective or transmissive surface relief grating having a grating pattern with deep grooves. A grating with deep grooves formed in this manner has high diffraction efficiency and is very useful in practice.

Next, FIGS. 3 and 4 are process explanatory diagrams showing another embodiment of the grating manufacturing method according to the present invention, in which an in-plane magnetized film such as Fe2O is used as a magnetic recording medium, and the magnetization of the magnetization pattern is This is an example in which the direction is the in-plane direction.

FIG. 3(1) shows, for example, FIG. As shown in
It schematically shows a magnetization pattern in the in-plane direction in which a 1.0 pattern was written and recorded by the magnetic head 11, and the small arrow shown in the figure indicates the magnetization direction. That is, as a result of writing by the magnetic head 11, the clock signal 13
An array of magnetic domains with mutually reversed in-plane magnetization directions is formed corresponding to 1 and 0 of . The pitch of this magnetic domain arrangement is usually 1
~ several μm. Note that the left-right direction in the figure corresponds to the longitudinal direction of the tape 10 or the circumferential direction of the disk 14.

Next, as shown in FIG. 3(2), a well-known bit pattern is applied onto the in-plane magnetized film 2' on which the magnetization pattern is formed by in-plane magnetization.
When a magnetic colloidal fluid with a particle size of about 100 to 200 particles is deposited using the method, the magnetic colloidal fluid 3 forms a magnetization pattern formed on the in-plane magnetized film 2', as shown in FIG. 3(2). Since the particles gather at the boundaries of the magnetic domains, a periodic pattern having the same pitch as the magnetization pattern is formed by the magnetic colloidal fluid 3.

Next, as shown in FIG. 3 (3), metal such as gold is deposited on the pattern (bitter pattern) formed by the magnetic colloidal fluid by vapor deposition or sputtering, and a layer thickness of 20
A metal covering M4 of approximately 001 is formed.

Next, after forming the metal coating 4 as shown in FIG. 3 (3) and FIG. 4 (3), as shown in FIG. A curable transparent resin 5, for example, an optical epoxy resin, is stacked by coating or pouring, and is irradiated with ultraviolet rays, which is then cured by applying heat. After solidifying the transparent resin, l1ff5, as shown in FIG. 4(5), the metal coating 4 and the resin layer 5 are peeled off from the in-plane magnetized film 2' to produce a replica of the lattice pattern. At this time, since the metal coating 3 is neatly adhered to the resin layer S side, a reflective surface relief grating having an uneven grating pattern is obtained. This reflective surface relief grating is a surface reflective grating in which a magnetization pattern due to in-plane magnetization is copied as an uneven pattern on the surface of a metal coating, and has the same pitch as the magnetization pattern. In addition, Fig. 4 (3) to Fig. 4 (5)
) can be repeated to obtain the same reflective surface relief grating one after another.

By the way, when producing the above-mentioned reflection type surface relief grating, it is preferable to use gold as the metal coating material, but when producing a transmission type diffraction grating etc., the method shown in Figs. In the step (3), for example, a metal film 4 is formed using a metal material that can be easily chemically etched instead of gold, and then a transparent resin layer 5 is laminated in the step (4) in FIG. After solidifying the resin, as shown in the fourth step (5), the metal coating 4 and the resin layer 5 are peeled off from the in-plane magnetized film 2'.
Furthermore, by removing the metal coating 4 from the resin layer 5 by etching, a transmission type surface relief grating as shown in FIG. 4(6) can be produced.

In addition, when gold is used for the metal coating, it can be removed by etching with aqua regia.

By the way, a lattice pattern can be manufactured using the in-plane magnetized film 2' by the manufacturing process shown in FIGS. The magnetic flux generated to the outside is not strong, and as a result, the adhesion of the magnetic colloidal fluid does not occur sufficiently, making it difficult to fabricate a diffraction grating with deep grooves.

Therefore, as a method to improve this, as shown in FIG.
A permanent magnet 7 is disposed close to the magnetic colloidal fluid 3 while applying a bias magnetic field 8 using the permanent magnet 7. In this way, when the bias magnetic field 8 is applied when the magnetic colloidal fluid 3 is attached, the magnetic flux density that diverges outward from the boundary where the direction of magnetization is facing increases among the in-plane magnetization, and the magnetic flux density is selectively applied to this part. The magnetic colloidal fluid 3 is attached to the magnetic colloidal fluid 3. At this time, the amount of attached magnetic colloid fluid increases significantly compared to when there is no bias magnetic field. Therefore, as shown in FIG.
After forming the lattice pattern according to the previous figure 3 (3)
Then, a metal coating 4 is laminated in the same manner as in the step of FIG. 4 (3),
By performing the transfer onto the transparent resin layer 5 in the steps shown in FIG. 4(4) to FIG. 4(5), a reflective surface relief grating having a deep grating pattern of uneven grooves can be produced. Further, by removing the metal film in the step of FIG. 4(6), a transmission type surface relief grating having a grating pattern with deep grooves of unevenness can be produced.

Now, the grating with deep grooves formed as described above has a high single diffraction efficiency and is very useful in practice.

In the embodiments shown in FIGS. 2 and 5, permanent magnets were used as means for applying the bias magnetic field. It is also possible to apply

〔Effect of the invention〕

As described above based on the illustrated embodiment.

According to the present invention, a novel method for producing a grid can be provided.

With the grating manufacturing method according to the present invention, reflective and transmissive surface relief gratings can be obtained easily, reliably, and at low cost. In particular, by using a perpendicular magnetization film as a magnetic recording medium and writing a magnetic pattern thereon with a magnetic head for perpendicular magnetization, it is possible to create an ultra-fine lattice pattern with a minimum pitch of 0.1 μm. In conventional lattice pattern formation, this is barely possible by pattern drawing using X-rays, but with X-ray drawing, it is difficult to produce the mask necessary for this, and it is difficult to actually achieve this. However.

According to the present invention, it is possible to easily produce a grating having an ultra-fine grating pattern as described above.

In addition, when forming a magnetization pattern by one-plane magnetization,
In particular, it simplifies the production of gratings having a pitch of 1 μm or more.

Furthermore, in the grating manufacturing method according to the present invention, if a bias magnetic field is applied during pattern formation using magnetic colloidal fluid, the amount of adhered magnetic colloidal fluid can be significantly increased. Therefore, it is possible to fabricate a grating with deep uneven grooves, and it is possible to improve the single diffraction efficiency, which is very useful in practice.

Furthermore, in the present invention, since the lattice pattern is written on the magnetic recording medium by a magnetic head, it is easy to increase the area, and furthermore, various lattice patterns can be easily realized.

Therefore, it is possible to fabricate not only gratings for encoders as shown in the examples, but also diffraction gratings for spatial light modulators, etc. Also, by writing a hologram pattern calculated by a computer with a magnetic head, computer holograms can be created. A phase-type hologram having a pattern can also be easily produced as a grating.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the grating manufacturing method according to the present invention, and is an explanatory diagram of the process when a perpendicularly magnetized film is used for the magnetic recording medium, and FIG. FIG. 6 is an explanatory diagram when a bias magnetic field is applied during pattern formation using a fluid. 3 and 4 are diagrams showing another embodiment of the grating manufacturing method according to the present invention, and are process explanatory diagrams when an in-plane magnetized film is used in the magnetic recording medium, and FIG. FIG. 3 is an explanatory diagram when a bias magnetic field is applied during pattern formation using a magnetic colloid fluid in the process of FIG. Fig. 6 is an explanatory diagram of a method of writing a magnetization pattern onto a magnetic recording medium formed on a tape-shaped substrate, and Fig. 7 is an explanatory diagram of a method of writing a magnetization pattern onto a magnetic recording medium formed on a disk-shaped substrate. It is an explanatory diagram of a method. 1...Substrate, 2...Magnetic recording medium for perpendicular magnetization, 2'...Magnetic recording medium for in-plane magnetization, 3...
Magnetic colloidal fluid, 4... Metal coating, 5... Transparent resin, 7... Permanent magnet for applying bias magnetic field, 8
...Bias magnetic field. fig fig fig fig fig fig fig fig fig fig fig fig fig fig fig fig.

Claims (1)

[Claims] 1. A method for producing a surface relief lattice pattern, which comprises recording a desired lattice-shaped magnetization pattern on a magnetic recording medium formed in layers on a substrate using a magnetic head; Contacting a magnetic colloidal fluid in which the particle size of colloid particles is sufficiently smaller than that of the magnetization pattern on the magnetic recording medium on which this magnetization pattern is recorded, producing a pattern of the magnetic colloid fluid corresponding to the magnetization pattern, Next, a metal coating is laminated on the magnetic colloidal fluid pattern, an unsolidified transparent resin layer is laminated, and after the resin layer is solidified, the metal coating and the resin layer are removed from the magnetic recording medium. A method for producing a grating characterized by producing a reflective surface relief grating by peeling. 2. A method for producing a surface relief-type lattice pattern, in which a desired lattice-shaped magnetization pattern is recorded on a magnetic recording medium formed in layers on a substrate using a magnetic head, and this magnetization pattern is recorded. A magnetic colloidal fluid whose colloidal particles have a particle size sufficiently smaller than the magnetization pattern is brought into contact with the magnetic recording medium, to produce a pattern of magnetic colloidal fluid corresponding to the magnetization pattern, and then the magnetic colloid is After forming a metal coating over the fluid pattern, an unsolidified transparent resin layer is laminated, and after the resin layer is solidified, the metal coating and the resin layer are peeled off from the magnetic recording medium. A method for producing a grating, characterized in that a coating is removed from a resin layer to produce a transmission type surface relief grating. 3. In the method for producing a grid according to claims 1 and 2,
A method for producing a grating characterized by applying a bias magnetic field when bringing magnetic colloidal fluid into contact and forming a pattern of magnetic colloidal fluid corresponding to a magnetization pattern.