TWI478159B - Patterning of magnetic thin film using energized ions, apparatus for processing recording media and magnetic recording medium - Google Patents

Description

Method for patterning magnetic film using energized ions, device for processing recording medium, and magnetic recording medium

The present invention relates generally to the patterning of magnetic thin films and, more particularly, to methods of using energized ions to pattern magnetic thin films of magnetic recording media.

There has been a need for higher density information storage media for computers. Nowadays, the common storage medium is a hard disk drive (HDD). HDD is a non-volatile storage device that stores digitally encoded data on a fast rotating disc with a magnetic surface. The disc is circular with a central hole. The disc is made of a non-magnetic material (usually glass or aluminum) and coated on one or both sides with a magnetic film such as a cobalt-based alloy film. The HDD records data by magnetizing the area of the magnetic film in one of two specific orientations, thereby allowing binary data storage in the film. The stored data is read by detecting the orientation of the magnetized region of the film.

A typical HDD design consists of a shaft holding one or more discs that are sufficiently spaced apart to allow the head to access one or both of the discs. The disc is fixed to the shaft by a clamp inserted into a central hole in the disc. The disc spins at a very high speed. As the disc rotates past the head, information is written to and read from the disc. The heads are moved to the surface immediately adjacent to the magnetic film. The head is used to detect and/or correct the magnetization of the material immediately below it. There is a read/write head for each disk surface on the shaft. One arm moves the heads across the spin disk, thereby allowing each head to access substantially the entire surface of the corresponding disk.

In conventional magnetic media, each bit cell includes a plurality of randomly dispersed magnetic particles. Ideally, the plurality of magnetic particles are physically separated from one another to provide improved writing capability, signal to noise ratio (SNR), and thermal stability.

As the magnetic recording density of the magnetic recording medium increases, the number of bit cells per square inch increases. This reduces the size of the bit cell. To effectively measure the transition, a minimum number of magnetic particles are required in the bit cell. As the size of the bit cell decreases, the magnetic particle size must be correspondingly reduced to provide a minimum number of magnetic particles in the bit cell. If the magnetic particles are previously isolated and the size of the magnetic particles is reduced to ensure low noise, the recording density will be limited due to thermal interference.

In order to improve the recording density, it is necessary to reduce the size of the recording unit on the medium, which results in a decrease in the intensity of the signal magnetic field generated by the medium. In order to meet the SNR required by the recording system, noise must be reduced corresponding to a reduction in signal strength. Media noise is primarily caused by fluctuations in the magnetization transition, and this fluctuation is proportional to the size of the magnetization reversal unit made of magnetic particles. Therefore, in order to reduce media noise, it is necessary to isolate the magnetic particles by disrupting the exchange interaction between the magnetic particles.

The magnetic energy of a single isolated magnetic particle is derived from the product of the magnetic anisotropy energy density and the volume of the particle. In order to reduce the magnetization transition width, it is necessary to reduce the thickness of the medium. It is also necessary to reduce the particle size to meet the requirements of low noise. The reduced magnetic particle size significantly reduces the volume of the magnetic particles and further significantly reduces the magnetic energy of the particles. Thermal interference resistance is considered sufficient if the magnetic energy of a given magnetic particle in a magnetic medium is hundreds of times the thermal energy at the operating temperature (e.g., at room temperature). However, if the magnetic energy of the magnetic particles is less than one hundred times the thermal energy, there is a possibility that the magnetization direction of the magnetic particles may be reversed due to thermal interference, which may result in loss of recorded information.

Various alternatives have been proposed to overcome the problem of thermal interference. An alternative is to use a magnetic material with high magnetic anisotropy. These magnetic materials require a higher recording saturation magnetic field from the head to write to the magnetic media. Another alternative uses heat assisted recording in which a highly anisotropic magnetic material is used and the recording portion is heated by light irradiation during recording. The heat reduces the anisotropy of the magnetic particles and the recording saturation magnetic field. This reduction allows the use of conventional magnetic heads for writing to magnetic media.

As the magnetic recording density increases, there is a minimum number of magnetic particles that are still required per bit cell, and there is a limit to what magnetic particles can actually be achieved.

An alternative magnetic medium under study is a patterned medium in which the magnetic portion alternates with the non-magnetic portion. For example, the bit patterned medium can have a magnetic portion that defines a magnetic domain as an island surrounded by a non-magnetic portion. The trajectory patterned medium can have, for example, a concentric trajectory of magnetic portions separated by non-magnetic portions.

Various alternatives have been proposed to make such media, however, there is still a need to propose a method that is cost effective and compatible with mass manufacturing. Herein, embodiments of the present disclosure propose the method.

The concepts and methods of the present disclosure allow for the mass production of magnetic media in which portions of the magnetic film exhibit magnetic properties that are different from other portions of the magnetic film.

In one aspect, the present disclosure is a method of patterning a magnetic film on a substrate. The method includes providing a pattern around the magnetic film, wherein the selective region of the pattern allows energized ions of one or more elements to penetrate and impinge on portions of the magnetic film. The energized ions of one or more elements are generated to have sufficient energy to penetrate a selective region of the pattern and a portion of the magnetic film adjacent to the selective regions. The substrate is placed to receive the energized ions. The portions of the magnetic film adjacent to the selective regions exhibit magnetic properties that are different from other portions of the magnetic film that are selective.

In another aspect, the present disclosure is a method for patterning a magnetic medium having two sides (having a magnetic film on both sides). The method includes providing a pattern around the magnetic film on both sides of the magnetic medium, wherein the selective region of the pattern allows energized ions of one or more elements to penetrate and impinge on portions of the magnetic film. The energized ions of one or more elements are generated to have sufficient energy to penetrate a selective region of the pattern and a portion of the magnetic film adjacent to the selective regions on both sides of the magnetic medium. The magnetic media is placed to receive energized ions. The portions of the magnetic film adjacent to the selective regions on both sides of the magnetic medium exhibit magnetic properties that are different from other portions of the magnetic film that are selective.

The present disclosure will be described in detail with reference to the drawings, which are provided as an illustrative example of the present disclosure. In particular, the figures and the following examples are not intended to limit the scope of the disclosure to a single embodiment, and other embodiments are possible by interchangeing some or all of the elements described. In addition, where certain components of the present disclosure are partially or fully implemented using known components, only those portions of such known components that are necessary for the understanding of the present disclosure will be described and will be omitted. Detailed descriptions of other parts of the components are known to avoid obscuring the disclosure. In the present specification, an embodiment showing a separate component is not to be considered as limiting; rather, the present disclosure is intended to cover other embodiments including a plurality of identical components, and vice versa, unless explicitly stated otherwise herein. In addition, the Applicant does not intend to attribute any term in the specification or the scope of the patent application to a non-ordinary or specific meaning (unless so clearly stated). Further, the present disclosure encompasses present and future known equivalents of the known components referred to herein by the description.

In general, the present disclosure contemplates providing a pattern in which the selective regions allow ions of one or more elements to penetrate and impinge on portions of the magnetic film. The energized ions of one or more elements are generated to have sufficient energy to penetrate a selective region of the pattern and a portion of the magnetic film adjacent to the selective region. The substrate is placed to receive energized ions. The portion of the magnetic film adjacent to the selective region exhibits magnetic properties different from those of the other portions of the magnetic film. This method can be used for hard disk drive manufacturing, which allows for the storage of information at extremely high magnetic recording densities.

An exemplary method of the present disclosure is shown in FIG. The method for patterning a magnetic film on a substrate comprises the steps of: (1) providing a pattern around the magnetic film, wherein the selective region allows penetration of energized ions of one or more elements; (2) generating one or more An energized ion of an element having sufficient energy to penetrate a selective region of the pattern and a portion of the magnetic thin film adjacent to the selective region; (3) placing the substrate to receive the energized ions And (4) the portion of the magnetic film adjacent to the selective region exhibits a magnetic property different from that of the other portions of the magnetic film.

In one embodiment, a mask having a selective region that allows ion penetration and that does not contribute to energized ion penetration can be used as a pattern. Figure 2 shows a partial plan view of an exemplary mask 200 for use as a pattern around a magnetic film. For example, the mask 200 can be made of a polymeric material (eg, a polyvinyl alcohol (PVA) material) that has a portion 202 that does not contribute to the penetration of energized ions and a choice that facilitates the penetration of energized ions. Sexual area 204. An exemplary method of establishing a PVA template is described in U.S. Patent No. 6,849,558, the disclosure of which is incorporated herein by reference. The teachings of Schaper can be adapted to create a mask 200 having a portion 202 that does not contribute to the penetration of energized ions and a selective region 204 that facilitates the penetration of energized ions. For example, the thickness of portion 202 can be selected such that energized ions do not completely penetrate portion 202. Although portion 202 has been shown as being circular, the shape and location of portion 202 can be advantageously selected as would be appreciated by those skilled in the art. For example, the shape of portion 202 can be elliptical, square, rectangular, or any other shape depending on the needs of the application.

In yet another embodiment, a resist can be applied to the magnetic film and a pattern can be created in the resist, for example, using nanoimprint lithography. There are two well known types of nanoimprint lithography that can be used in the present disclosure. The first type is thermoplastic nanoimprint lithography [T-NIL], which includes the following steps: (1) coating the substrate with a thermoplastic polymer resist; (2) contacting the mold having the desired three-dimensional pattern with the resist And applying a specified pressure; (3) heating the resist to above its glass transition temperature; (4) molding the resist to the resist when it exceeds its glass transition temperature; (5) cooling the resist and blocking the mold The agent separates, thereby leaving the desired three-dimensional pattern in the resist.

The second type of nanoimprint lithography is photon nanoimprinting [P-NIL], which comprises the following steps: (1) applying a photocurable liquid resist to the substrate; (2) a transparent film having a desired three-dimensional pattern is pressed into the liquid resist until the mold is in contact with the substrate; (3) the liquid resist is cured in ultraviolet light to turn the liquid resist into a solid; and (4) separating the mold from the resist, Further, the desired three-dimensional pattern is left in the resist. In P-NIL, the mold system is made of a transparent material such as a fusion vermiculite.

Figure 3 shows a cross-sectional representation of an exemplary pattern 300 after nanoimprint lithography. The patterned resist 310 on the magnetic film 320 on the substrate 330 is shown as having a recess 340 with a selective region 350 that has substantially displaced the resist at the selective region 350. However, the selective region 350 leaves a small amount of resist covering the surface of the magnetic film 320. This is typical for nanoimprinting processes. When a resist pattern is used as a mask for ion implantation, it is not necessary to remove all of the resist layer in the region where the implant material will be implanted. However, the remaining layer should be thin enough so as not to cause the substantial barrier for the implanted material to be penetrated. Further, the contrast between the region having the thick resist and the region having the thin residual resist should be sufficiently large, so that the resist in the region having the thick resist can stop the ionic substance before it reaches the magnetic film. Alternatively, an isotropic resist removal process, such as a slag removal process or a slight ash process or any other suitable technique, can be used to remove the thin residual resist in the selective region 350.

In nanoimprint lithography, when the imprinting process shifts the resist to form the selective region 350, it is necessary to control when a mold having a plurality of protrusions corresponding to the recess 340 is brought into contact with the resist and pressure is applied. The amount of the resist that is subjected to displacement. Generally, the width w of the recess 340 can be about the same size as the depth d of the recess 340 and the height h of the resist is at least as high as the depth d of the recess 340 to control the amount of resist that is subject to displacement during the stamping process. If the depth d of the recess 340 is substantially higher than the width w of the recess 340, the amount of resist that is subject to displacement may be so high that it may not be implemented to accurately transfer the pattern from the mold to the resist 310.

A nano-imprint lithography process can be implemented using a full-disc nanoimprinting scheme in which the mold is large enough to imprint an entire surface. Alternatively, a one step and repeated imprint process can be used. In the preferred embodiment, a full disc scheme is used. The nanoimprint process can also be performed with both sides. For example, a resist layer can be first applied to both sides of the disc. Subsequently, the disc enters a press that presses the mold against both sides of the disc to simultaneously imprint the desired pattern on both sides of the disc.

It is also possible to use a conventional photolithography process in which the photoresist is spun on the disc, then the resist is exposed through the mask, and the exposed resist is developed.

After patterning, the disc has a pattern of resists wherein the selective regions 350 of the pattern allow energized ions to penetrate and impinge on portions of the magnetic film 320 adjacent the selective regions 350. The portion of the resist other than the selective region 350 (e.g., portion 360) is of sufficient thickness to prevent energized ion penetration and thereby prevent energized ions from impinging on the magnetic film.

If the mask 200 is used instead, the mask 200 is placed adjacent to the magnetic film, and the selective region 204 of the mask 200 allows the ionized ion to penetrate the mask and impinge on the adjacent region 204. On the part of the magnetic film. In an embodiment, the mask 200 is positioned in close proximity to the magnetic film. In another embodiment, the mask 200 is positioned in contact with a magnetic film or a magnetic film covered with a coating. The coating can help the mask adhere. The coating can also act as a protective coating on the magnetic film. The coating can be a carbon layer that acts as a protective coating on the magnetic film.

Referring now to Figure 1, in step 104, energized ions of one or more elements are generated to have sufficient energy to penetrate a selective region of the pattern and impinge on portions of the magnetic film adjacent to the selective region. In one embodiment, a vacuum chamber is provided and one or more gases containing a compound of one or more elements are injected. The plasma is ignited by the use of a high voltage and the energized ions of one or more elements are released.

In step 106, the substrate is placed to receive energized ions. In one embodiment, the substrate is placed in a vacuum chamber that produces energized ions of one or more elements. In one embodiment, the substrate is placed in a plasma containing one or more energized ions. In an embodiment, the substrate is biased to attract energized ions. If mask 200 is used, the energized ions pass through selective region 204 of mask 200 and impinge on portions of the magnetic film adjacent to selective region 204. If the resist 310 is used as a pattern, the energized ions pass through the selective region 350 and impinge on portions of the magnetic film adjacent to the selective region 350. In one embodiment, the energized ions penetrate into portions of the magnetic film adjacent to the selective region 350. In an embodiment, the energized ions partially penetrate into portions of the magnetic film adjacent to the selective region 350. In one embodiment, the energized ions substantially penetrate into portions of the magnetic film adjacent to the selective region 350.

In an embodiment, plasma ion immersion implantation may be used to provide a high implant dose at low energy. Since the sputtered magnetic film is usually only a few tens of nanometers thick, low ion energy is effective and high doses provide high throughput. In addition, as illustrated in Figure 4, plasma ion implantation on both sides of the disc can be performed simultaneously. Although bilateral plasma ion implantation is preferred, single-sided plasma ion implantation can be used without departing from the spirit of the present disclosure. In a single-sided plasma ion implantation, the first side is implanted, then the disc is flipped and implanted on the second side.

A plasma ion implantation tool 400 for mounting a disc is shown in FIG. 4, such as a substrate having a magnetic film having a pattern around the magnetic film, the selective area of the pattern allowing one or more elements The energized ions penetrate and impinge on portions of the magnetic film.

Referring to Figure 4, chamber 410 is maintained under vacuum by vacuum pump 420. Gas supply 430 is coupled to chamber 410 by tube 432 and valve 435. More than one gas may be supplied via valve 435, and multiple gas supplies and valves may be used. For example, the chamber 410 may be supplied with a dopant gas containing one or more substance elements. The rod 440 holds the disc 450. A radio frequency (RF) power source 460 is coupled between the rod 440 and the wall of the chamber 410. The wall of the chamber 410 is connected to an electrical earth. In addition to the RF power source, an impedance matching device and a power source for applying a direct current (DC) bias can be included. The rod 440 can be coated with graphite or ruthenium to protect it from plasma. In addition, the rod and its surface are highly conductive to promote good electrical contact between the rod and the disc. The disc 450 can be secured in place using a clamp 455 or other tool; the clamp 455 not only holds the disc 450 in place but also ensures a good electrical connection between the disc 450 and the rod 440. The assembly rods carry many discs (for ease of illustration, only three discs 450 are shown). Additionally, the chamber 410 can be assembled to hold a plurality of rods carrying discs for simultaneous plasma ion implantation. The rod 440 can be easily moved into and out of the chamber 410.

The processing of the disc in the plasma ion implantation tool 400 is performed as follows. One or more of the discs 450 are loaded onto the rod 440. The rod 440 is loaded into the chamber 410. Vacuum pump 420 operates to achieve the desired chamber pressure. The desired gas containing the implant material leaks from the gas supply 430 into the chamber via valve 435 until the desired operating pressure is reached. The RF power source 460 is operative to ignite the plasma surrounding the surface of one or more of the discs 450. A DC power source can be used to control the energy of ions implanted in the magnetic film. RF bias can also be used.

The ions that can be easily self-plasma implanted and can effectively correct the magnetic properties of typical sputtered magnetic films (such as Co-Pt and Co-Pd) are: hydrogen, helium, boron, sulfur, aluminum, lithium, strontium and barium. And a combination of these elements. This list is not intended to be exhaustive. Any ion system that is easily formed in the plasma and is effective in correcting the magnetic properties of the magnetic film is sufficient. Ideally, it is preferred to change the magnetic properties of the magnetic film to a thermally stable, less magnetic or multi-magnetic region ion at the lowest dose.

Other details of the plasma ion implantation chamber and process methods are available in U.S. Patent Nos. 7,288,491 and 7,291,545, the entireties of each of which are incorporated herein by reference. The main difference between the chamber of the present disclosure and the chamber of Collins et al. is the different configurations for holding the substrate. The disc holder of the present disclosure allows for implantation on both sides together, while the substrate of Collins et al. is located on the wafer chuck during processing. Those skilled in the art will appreciate how the plasma ion implantation tools and methods of Collins et al. can be utilized in this disclosure.

After the substrate is placed in step 106 to receive the energized ions, a portion of the magnetic film adjacent to the selective region can be subjected to thermal excitation in step 108. In an embodiment, radio frequency or microwave energy can be used to heat the selective region. In yet another embodiment, the substrate can be heated. In yet another embodiment, a laser or flash anneal can be performed. In some embodiments, a rapid high thermal annealing or boiler can be used.

As will be appreciated by those skilled in the art, the thermal excitation step 108 can be performed from a resist layer that is still present on the magnetic film. In some embodiments, the resist layer can be removed and the magnetic film subjected to thermal excitation. In this embodiment, a magnetic film having a portion subjected to ion implantation and a portion not subjected to ion implantation will be subjected to thermal excitation. This method can be advantageously used for certain types of magnetic films that can benefit from thermal excitation, for example, for portions of magnetic films that are not ion implanted.

If a mask 200 (eg, a PVA mask) is used, the process may additionally include removal of the mask 200. In one embodiment, the process of dissolving the PVA mask 200 (eg, using an aqueous solution) can be used to remove the PVA mask. In some embodiments, a non-aqueous solution can be used. In some embodiments, the mask 200 is removed and then the magnetic film is subjected to thermal excitation. In this embodiment, a magnetic film having a portion subjected to ion implantation and a portion not subjected to ion implantation will be subjected to thermal excitation. This method can advantageously be used with certain types of magnetic films that can benefit from thermal excitation, for example, for portions of magnetic films that are not ion implanted. In some embodiments, the thermal excitation step 108 can be performed with the mask 200 that is still present.

In some embodiments, the magnetic film can be subjected to thermal excitation in the chamber 410 of the ion implantation tool 400 by incorporating a suitable heat source in the chamber 410 and selectively opening the heat source after ion implantation.

After thermal excitation in energized ion step 106 and/or step 108, as illustrated in step 110, portions of the magnetic film adjacent to the selective region exhibit magnetic properties that are different from other regions of selectivity. In one embodiment, the energized ions that penetrate into portions of the magnetic film adjacent the selective region 350 cause portions of the magnetic film adjacent to the selective region to exhibit magnetic properties that are different from other regions of selectivity. If the resist is used as a pattern, the process may additionally include a resist stripping step. The resist stripping step can be facilitated by conventional slag removal and ash operations in the plasma ion implantation chamber prior to removal of the disc. The resist stripping step can be a wet chemical process well known in the art. In some embodiments, the resist stripping step can be performed prior to the thermal excitation step 108, as discussed above.

The energy of the ions obtainable from the plasma implantation process is in the range of from about 100 eV to about 15 keV. However, for implantation into a magnetic film of several tens of nanometers thick, the desired energy range is between about 1 keV and about 11 keV. The energy range selected is based on the selected element, the thickness of the resist, the stopping ability of the resist ions, and the desired magnetic properties. For example, a bias voltage of about 1 kV to 11 kV can be used to generate the desired energy range.

Figure 5 is a cross-sectional representation of a pattern 510 disposed about the magnetic film 520, with arrow 530 indicating the general direction of bombardment of energized ions. The energized ions penetrate the selective region 540 of the resist 510 and penetrate a portion 550 of the magnetic film 520 adjacent the selective region 540.

Figure 6 is a cross-sectional representation of magnetic film 520 after ion implantation in which portion 550 is subjected to ion implantation. Portion 550 of magnetic film 520 exhibits magnetic properties that are different from the selective other portions 560 of magnetic film 520.

The following examples are provided to illustrate various applications of ion implantation to achieve the desired magnetic properties.

Example:

Experiments were conducted to determine the ion cessation properties of the resist against bismuth and boron ions for a given bias voltage.

Helium ion implantation: Experiments were carried out on helium ion implantation at 7kV and 2kV bias voltages. At 7 kV, the thickness of the resist required to stop the ruthenium ions from penetrating the resist layer was about 120 nm. The resist thickness at the selective regions of the pattern can be as high as 45 nm and still provide penetration of the 20 nm thick Co-based magnetic film adjacent to the selective region of the pattern. At 2 kV, the thickness of the resist required to stop the ruthenium ions from penetrating the resist layer was about 85 nm. The thickness of the resist at the selective regions of the pattern can be as high as 10 nm and still provide penetration of the 20 nm thick Co-based magnetic film adjacent to the selective region of the pattern.

Boron ion implantation: Experiments were carried out on boron ion implantation at a bias voltage of 9 kV. At 9 kV, the thickness of the resist required to stop the boron ions from penetrating the resist layer is about 65 nm. The thickness of the resist at the selective regions of the pattern can be as high as 10 nm and still provide penetration of boron ions to a 20 nm thick Co-based magnetic film adjacent to the selective regions of the pattern.

Magnetic properties: Example 1a:

A glass substrate sputtered with a soft underlayer of a FeNi alloy of about 100 nm was used. A magnetic thin film layer of about 20 nm of a CoCrPt alloy was sputtered on a soft underlayer of FeNi alloy. The prepared sample as described above is subjected to a plasma containing He ions by injecting a doping gas into the process chamber. The process chamber pressure was about 15 mtorr, the RF bias voltage was about 2 kV, the source power was about 500 watts, the doping gas was injected at a flow rate of about 300 sccm and the implantation time was about 25 seconds. Depending on the situation, an inert gas may also be injected to assist in the generation of plasma. For example, argon may also be injected at a flow rate of about 16 sccm.

A simulation program having the above process parameters is used to depict the penetration profile of He ions into the sample. The simulation can be performed using a simulation program known as TRIM. The TRIM program can be used as part of a program group known as SRIM from www.srim.org. Figures 7A and 7B show the results of the simulation. Referring now to Figure 7A, it is apparent that a resist of about 85 nm thick is sufficient to stop the energization of He ions into the CoCrPt magnetic film layer. Referring now to Figure 7B, it is apparent that a resist layer of about 10 nm and a carbon layer of about 28 angstroms will be successfully penetrated by energized ions, and the energized ions further substantially penetrate the CoCrPt magnetic thin film layer of about 20 nm.

A magnetic property of a magnetic film for a sample that has not been implanted with He ions is measured using a Physical Property Measurement System to establish a baseline. After subjecting the sample to He ion implantation, the magnetic properties of the portion of the magnetic film subjected to He ion implantation were measured using a physical mass measurement system. Figure 7C shows the magnetization curve of a magnetic film that has not been implanted with He ions. From the 7C chart, it is apparent that the saturation magnetic force (Ms) is about 1.36 Tesla. Fig. 7D shows the magnetization curve of a portion of the magnetic film subjected to He ion implantation. From Fig. 7D, it is apparent that the saturation magnetic force (Ms) of the portion of the magnetic film subjected to He ion implantation has dropped to about 0.1 Tesla as compared with the baseline magnetic film which has not been implanted with He ions. Therefore, the magnetic thin film can be subjected to He ion implantation under appropriate process conditions to substantially change the magnetic properties to a state in which the selective portions exhibit significantly different magnetic properties.

Example 1b:

A sample similar to that used in Example 1a was used in Example 1b except that the sample was subjected to high thermal annealing. The high thermal annealing is performed in a vacuum at a pressure of about 10 torr to about 5 torr at about 100 degrees Celsius and about 200 degrees Celsius for about one hour.

After subjecting the sample to high thermal annealing, the magnetic properties of portions of the magnetic film subjected to He ion implantation and high thermal annealing were measured using a physical mass measurement system. The baseline magnetization curve of the magnetic film not implanted with He ions exhibits a saturation magnetic force (Ms) of about 1.36 Tesla. The magnetization curve of a portion of the magnetic film subjected to He ion implantation and high thermal annealing at 100 degrees Celsius exhibits a saturation magnetic force (Ms) of about 0.01 Tesla. The magnetization curve of a portion of the magnetic film subjected to He ion implantation and high thermal annealing at 200 degrees Celsius exhibits a saturation magnetic force (Ms) of about 0.03 Tesla. Based on the results of the samples in Examples 1a and 1b, it is apparent that the high thermal annealing of the sample further reduces the saturation magnetic force (Ms) of the portion of the magnetic film that is subjected to annealing. Therefore, the magnetic film can be subjected to He ion implantation and high thermal annealing under appropriate process conditions to substantially change the magnetic properties to a state in which the selective portions exhibit significantly different magnetic properties. Although the experiment was conducted at a bias voltage of about 2 kV, the bias voltage may be in the range of 1 kV to 11 kV and preferably in the range of 1 kV to 3 kV.

Example 2:

A sample similar to that used in Example 1a was used for the penetration of boron ions. The prepared sample as described above is subjected to a plasma containing boron ions by injecting a doping gas BF ₃ into the process chamber. The process chamber pressure was maintained at about 15 mtorr, the RF bias voltage was about 9 kV, the source power was about 500 watts, the doping gas BF _{3 was} injected at a flow rate of about 300 sccm and the implantation time was about 20 seconds. Depending on the situation, an inert gas may also be injected to assist in the generation of plasma. For example, argon may also be injected at a flow rate of about 16 sccm.

A simulation program having the above process parameters is used to depict the profile of the penetration of boron ions into the sample. Figures 8A and 8B show the results of the simulation. Referring now to Figure 8A, it is apparent that a 65 nm thick resist will be sufficient to stop the energization of boron ions from penetrating into the CoCrPt magnetic film layer. From Figure 8A, it is apparent that a resist layer of about 10 nm and a carbon layer of about 28 angstroms can be successfully penetrated by energized ions. The energized ions can further substantially penetrate the CoCrPt magnetic thin film layer of about 20 nm.

Referring to Figure 8C, the concentration of boron and Co atoms was determined using a secondary ion mass spectrometer (SIMS). According to Fig. 8C, it is apparent that the Co concentration remains substantially unchanged. It is also apparent that the boron concentration remains constant for a depth of about 10 nm and then gradually decreases.

A magnetic quality property of a magnetic film for a sample that has not been implanted with boron ions is measured using a physical mass measurement system to establish a baseline. After subjecting the sample to boron ion implantation, a magnetic film subjected to boron ion implantation is measured using a physical mass measurement system. Figure 8D shows the magnetization curve of a magnetic film that has not been implanted with boron ions. As is apparent from Fig. 8D, the saturation magnetic force (Ms) is about 1.36 Tesla. Fig. 8E shows the magnetization curve of a portion of the magnetic film subjected to boron ion implantation. As is apparent from Fig. 8E, the saturation magnetic force (Ms) of the portion of the magnetic film subjected to boron ion implantation has dropped to about 0.5 Tesla as compared with the magnetic film not implanted with boron ions. Boron ion implantation under these experimental conditions reduced magnetization by about 50%.

Thus, the magnetic film can be subjected to boron ion implantation under certain process conditions to alter the magnetic properties of the selective portion to exhibit different magnetic properties. For example, the magnetic properties of the selective moiety can be altered to exhibit less magnetic properties than portions that are not implanted with boron ions. Although the experiment is conducted at a bias voltage of about 9 kV, the bias voltage may be in the range of 1 kV to 11 kV and preferably in the range of 7 kV to 11 kV.

Example 3:

A tantalum substrate sputtered with a Co alloy layer of about 20 nm was prepared as a sample for this example. The prepared sample is subjected to a plasma containing cerium ions by injecting a doping gas SiH ₄ into the process chamber. The process chamber pressure was about 30 mtorr, the RF bias voltage was about 9 kV, the source power was about 500 watts, the doping gas SiH4 was injected at a flow rate of about 75 sccm and the implantation time was about 20 seconds.

A simulation program having the above process parameters is used to depict the profile of the penetration of the erbium ions into the sample. Figure 9A shows the results of the simulation. Referring now to Figure 9A, it is apparent that Si penetrates about 5-6 nm deep, some of which are as deep as 10 nm deep.

After subjecting the sample to cerium ion implantation, the depth profile of the Si implant in the 20 nm Co film was measured using SIMS. Figure 9B shows the depth profile of the Si implant. From Figure 9B, it is apparent that Si ions penetrate about 5-6 nm deep. It is worth noting that the Si ion penetration depth profile depicted using the simulation program is fully correlated with the actual measurement of the Si penetration depth.

In some embodiments, after ion implantation, the magnetic film can be subjected to thermal excitation, for example, by high thermal annealing. As is apparent from Example 1b, it is expected that the high thermal annealing will further reduce the saturation magnetic force (Ms) of the portion of the magnetic film subjected to thermal excitation.

From the above examples, it is apparent that the thickness of the resist required to stop the energized ions from penetrating the resist layer and impinging on the magnetic film depends on the type of the element used, the process parameters, and the ion entry and the resist layer that allows the charged ions to penetrate. The depth of penetration of the magnetic film adjacent to the selective region depends on the depth of penetration. As the size of the selective region of the resist layer that allows charged ions to penetrate becomes smaller, it is desirable to reduce the thickness of the resist to allow efficient nanolithography during pattern generation. As the thickness of the resist decreases, the resist layer may no longer be able to stop the energized ions from penetrating beyond the selective regions.

One way to overcome this problem is to add a dopant to the resist that increases resistance to penetration by charged ions. For example, a ruthenium containing compound can be used to dope the resist to increase resistance to charged ion penetrating resists. Other dopants that can be used to increase resistance to penetration by charged ions include compounds containing sulfur and phosphorus. In one embodiment, nanoparticle can be added as an additive to adjust resistance to penetration of charged ions. For example, aluminum (Al ₂ O ₃ ), cerium oxide (SiO ₂ ), cerium oxide (CeO ₂ ), and titanium dioxide (TiO ₂ ) nanoparticles can be used to adjust the resistance to penetration of charged ions. Sex.

From the above examples, it is apparent that different element types have different effects on magnetic properties based on process parameters and the depth of penetration into the ion to magnetic film. For example, one or more elements can be advantageously used to modify the magnetic properties of the magnetic film. As an example, a combination of niobium and boron can provide increased benefits. For example, germanium having a smaller molecular weight can penetrate deeper in the magnetic film and change the magnetic properties using a smaller bias voltage. Boron having a higher molecular weight can be used before or after the penetration of the crucible to further affect the magnetic properties of the magnetic film, and boron also acts as a barrier for the erbium ions to prevent it from escaping from the magnetic film over time.

Although a combination of niobium and boron has been described, those skilled in the art will appreciate that various other permutations and combinations of elements can be used sequentially or together to yield magnetic and other properties that are beneficial for maintaining and enhancing magnetic properties.

Also from the above examples, it is apparent that different element types can be used to correct the magnetic properties of the magnetic film. For example, a compound containing an element that increases the magnetic properties of the film after ion implantation can be used. For example, platinum ion implantation can increase the magnetic properties of magnetic films.

The present disclosure is applicable to various types of magnetic recording media. For example, the teachings of the present disclosure are applicable to recording media having a granular magnetic structure. The present disclosure can also be applied to multilayer magnetic films. The magnetic film can also be a continuous magnetic film and can be used in patterned media. The patterned medium can be a bit patterned medium or a track patterned medium. In an embodiment, the magnetic film may be made of a highly anisotropic magnetic material suitable for thermally assisted magnetic recording.

This disclosure allows for extremely short process times. For example, it can take up about ten seconds to implant a disc. Input and output vacuum load locks will enable rapid transfer of the disc into or out of the chamber and avoid wasting time for pumping, allowing for extremely high throughput. Those skilled in the art will appreciate how automated transfer systems, robotics, and load-lock systems can be integrated with the plasma ion implantation apparatus of the present disclosure.

The present disclosure, in certain embodiments, provides a method of selectively modifying the magnetic properties of portions of a magnetic film of a magnetic medium. Selective correction can be advantageously used to increase one or more properties of desired properties such as magnetic recording density, write capability, SNR, and thermal stability of magnetic media.

Although the present disclosure has been specifically described with reference to the preferred embodiments of the present disclosure, it should be apparent to those skilled in the art that the invention may be practiced without departing from the spirit and scope of the disclosure. And changes and modifications to the details. The scope of the additional patent application is intended to cover such changes and modifications.

100. . . method

102. . . step

104. . . step

106. . . step

108. . . step

110. . . step

200. . . Exemplary mask/mask

202. . . Does not contribute to the passage of energized ions

204. . . a selective region that helps energize ions to penetrate

300. . . Exemplary pattern

310. . . Patterned resist

320. . . Magnetic film/film

330. . . Substrate

340. . . Depression

350. . . Selective region

360. . . section

400. . . Plasma ion implantation tool

410. . . Chamber

420. . . Vacuum pump

430. . . Gas supply

432. . . tube

435. . . valve

440. . . Rod

450. . . Disc

455. . . clamp

460. . . Radio frequency (RF) power supply

510. . . Pattern/resist

520. . . Magnetic film

530. . . arrow

540. . . Selective region

550. . . section

560. . . Selective other parts

These and other aspects and features of the present invention will become apparent from the <RTIgt;

1 is a process flow diagram of an exemplary method of the present disclosure; FIG. 2 is a partial plan view of an exemplary mask for use as a pattern around a magnetic film; and FIG. 3 is a pattern having a pattern disposed around the magnetic film. Exemplary resist; FIG. 4 is a schematic view of a process chamber for use in the present disclosure, showing a first disc holder device of the present disclosure; and FIG. 5 is a cross-sectional view of a pattern around the magnetic film; Figure 6 is a cross-sectional view of the magnetic film after ion penetration; Figures 7A and 7B show the helium ion penetration profile through the resist and the magnetic film; and Figure 7C shows the magnetic field without the ion implantation. a magnetization curve of a portion of the film; a 7D image showing a magnetization curve of a portion of the magnetic film subjected to erbium ion implantation; and FIGS. 8A and 8B are diagrams showing a boron ion penetration profile through the resist and the magnetic film; FIG. 8C The concentration of boron and cobalt ions in the magnetic film after boron ion implantation is shown; the 8D is a magnetization curve of a portion of the magnetic film not implanted with boron ions; and the 8E is a magnetic film subjected to boron ion implantation. Partial magnetization curve; ninth Panel A shows the helium ion penetration profile through the magnetic film; and Figure 9B shows the depth profile of the helium ions in the magnetic film after helium ion implantation.

Claims (23)

A method for patterning a film on a substrate, comprising the steps of: disposing a magnetic film on the substrate; and placing a pattern on the magnetic film, the pattern having a penetration permitting ionization of ions a selective region; positioning the substrate having the pattern thereon in a chamber; then injecting germanium and a boron-containing gas into the chamber, wherein the germanium and the boron-containing gas are then ionized into the plasma Implanting energized cerium ions and energizing boron ions into portions of the magnetic film, the magnetic film being adjacent to the selective regions of the pattern disposed on the substrate, wherein the substrate is at about 1 kV to about A bias voltage in a range of 11 kV; a portion of the magnetic film adjacent to the selective regions exhibits a magnetic property different from that of the other portions of the magnetic film. The method of claim 1, wherein the step of disposing the pattern comprises the step of positioning a mask adjacent to the magnetic film. The method of claim 2, wherein the mask comprises polyvinyl alcohol. The method of claim 1, wherein the step of arranging a pattern comprises the steps of: depositing a resist on the surface of the magnetic film; Contacting the resist with a mold having a three-dimensional pattern to create depressions in the resist, the depressions creating regions of thin resist and regions of thick resist, the thin resists corresponding to allowing energized ions to pass through Passing through the selective regions; and curing the resist. The method of claim 4, further comprising removing the resist. The method of claim 4, wherein the resist is deposited and cured on the surface of the magnetic film using thermoplastic nanoimprint lithography or light nanoimprint lithography. The method of claim 6 wherein the substrate is biased in the range of from about 1 kV to about 3 kV and the thin resist layer has a thickness of about 10 nm. The method of claim 4, wherein the step of placing a pattern on the magnetic film comprises the step of: placing a pattern on both sides of the substrate. The method of claim 1, wherein the energized helium ion and the energized boron ion are implanted at the same bias voltage, and the depth of the germanium ion implanted in the magnetic film is greater than The boron ion is The depth of implantation. A method for patterning a magnetic film on a substrate, comprising the steps of: providing a pattern around the magnetic film, wherein the selective region of the pattern allows energized ions of one or more elements to contact the magnetic film Parting; generating energized ions of one or more elements having sufficient energy to penetrate a selective region of the pattern and a portion of the magnetic film adjacent to the selective regions; exposing the substrate The energizing ions to cause the energized ions to contact the magnetic film; subjecting the portion of the magnetic film adjacent to the selective regions to thermal excitation; and locating the selective region adjacent thereto The magnetic film portion exhibits a magnetic property different from the other portions of the magnetic film. The method of claim 10, wherein the portion of the magnetic film adjacent to the selective regions exhibits a magnetic property different from that prior to the penetration of the ions. The method of claim 10, wherein the step of subjecting the portion of the magnetic film adjacent to the selective regions to thermal excitation further comprises the step of: making the magnetic film selective for other portions Subject to thermal excitation. The method of claim 12, further comprising the step of removing the pattern around the other portions of the selective moieties prior to subjecting the other portions of the magnetic film to thermal excitation. The method of claim 10, wherein the step of providing the pattern comprises the steps of: coating a resist on the magnetic film and using a plurality of protrusions having the selective regions corresponding to the pattern; Imprinting the stamp to create a depression in the resist, the recess having a width and a depth, wherein the resist surrounding the recess has a resist thickness at least as high as the depth of the recess and The thickness of the resist surrounding the recess is sufficient to substantially prevent energized ions from penetrating the resist surrounding the recess. The method of claim 14, wherein the step of subjecting the portion of the magnetic thin film adjacent to the selective regions to thermal excitation comprises the steps of: laser annealing, flash annealing, rapid high thermal annealing Or applying microwave energy to heat the magnetic film. The method of claim 10, wherein the step of providing a pattern around the magnetic film comprises the step of providing a pattern on both sides of the substrate. The method of claim 16, wherein the step of providing the pattern comprises the steps of: coating a resist on the magnetic film and using a plurality of protrusions having the selective regions corresponding to the pattern; The mold is embossed. The method of claim 17, wherein the step of generating an energized ion of one or more elements comprises the steps of: providing a vacuum chamber, injecting one or more gases containing one or more elements, by using high The voltage ignites a plasma and releases the energized ions of one or more elements, and exposing the substrate, the step of exposing the substrate includes the steps of: placing the substrate in the vacuum chamber and biasing the substrate to attract the Energy ions. An apparatus for processing a recording medium, comprising: a process chamber; a substrate support member disposed in the process chamber, the substrate support member having a plurality of substrate support sites on a surface thereof, the substrate support The device is adapted to support a plurality of magnetic recording media; a power source coupled to the process chamber and adapted to generate a plasma; and a doped gas supply coupled to the process chamber and adapted A doping gas is supplied to the interior of the process chamber. The device of claim 19, wherein the substrate support Contains a conductive surface. The device of claim 19, wherein the substrate support comprises a plasma protective coating. A magnetic recording medium comprising: a substrate having a plasma-doped magnetic film disposed thereon, the magnetic film comprising a cobalt alloy layer having: a first region having a doping ion concentration a pattern, wherein the first regions having a doping ion concentration exhibit a magnetic property different from a region adjacent to the first regions, and wherein the doping ions are selected from the group consisting of hydrogen, helium, boron, sulfur, A group consisting of aluminum, lithium, cesium, strontium, and combinations thereof. The magnetic recording medium of claim 22, wherein the dopant ion is ruthenium, and the dopant ion concentration is substantially constant for a depth of about 10 nm.