JP2011123927A - Method for manufacturing patterned medium type magnetic recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a patterned medium type magnetic recording medium preventing deterioration of a substrate surface in a manufacturing step, suppressing variation of worked shape and a loss time until discharge is stabilized and having a stable worked pattern shape and excellent reliability. <P>SOLUTION: When at least metal underlayers 11, 12 and 13, a magnetic recording layer 14 and a carbon layer 15 are layered in this order on a non-magnetic substrate 10 and then they are conveyed in a continuous vacuum device to perform process treatment by a plurality of process treatment vacuum chambers, the plurality of process treatment vacuum chambers are connected to each other via pressure adjusting chambers, respectively, an inert gas is introduced to the pressure adjusting chambers and pressure of each pressure adjusting chamber is set to be within ±25% to the pressure of an adjacent process treatment vacuum chamber. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a patterned media type magnetic recording medium used in a storage device used in information equipment such as a computer.

  The demand for higher recording density for storage devices used in information devices such as computers is increasing year by year. Also in a magnetic recording apparatus which is one of storage apparatuses, correspondence with a high recording density is being advanced. Measures such as changing the constituent materials, making the recording layer finer, and changing the magnetic recording method have been taken, but the improvement in recording density is reaching its limit. In order to further improve the recording density, a patterned media type magnetic recording medium such as a discrete track type or a bit pattern type in which the magnetic recording layer is processed into a fine uneven pattern is required. In order to form a desired fine concavo-convex pattern on the magnetic recording layer of such a patterned media type magnetic recording medium, an etching mask layer is formed on the surface of the magnetic recording layer to be a convex portion, and then dry etching is performed. A method of processing an unmasked magnetic recording layer surface is employed. As an etching mask layer for applying surface irregularities to the magnetic recording layer, there is a method in which a carbon layer is formed thicker than a normal protective layer. As a dry etching method, ion beam etching using an inert gas or reactive ion etching using a plurality of kinds of gases including a single reactive gas or a reactive gas is often used.

FIG. 1 is a schematic cross-sectional view of the magnetic recording medium shown in FIG. First, a soft magnetic layer 11, a seed layer 12, an intermediate layer (Ru alignment layer) 13, a magnetic recording layer 14, and a carbon layer 15 are formed in this order on a nonmagnetic substrate 10 to perform normal type magnetic recording without surface irregularities. Form a medium. Next, after spin-coating the resist film 16 on the carbon layer 15 (FIG. 1A), the resist film 16 is pressed by a stamper having a transfer pattern by an imprint method to form pattern irregularities on the resist film 16. Is formed (FIG. 1B). Using the patterned uneven step formed on the resist film 16, the carbon layer 15 and the magnetic recording layer 14 under the thin recess are etched to separate the magnetic recording layer 14 formed of a continuous film into a pattern. Specifically, the thin portion (recessed portion) of the resist film 16 is first removed by reactive ion etching (RIE) containing a halogen-based reactive gas (FIG. 1C), and the carbon layer 15 exposed thereunder is removed. Is removed by reactive ion etching (RIE) using oxygen gas, the magnetic recording layer 14 is exposed (FIG. 1D). The resist film 16 on the carbon layer 15 is removed (FIG. 1E). Next, with the carbon layer 15 as a mask, the portion of the magnetic recording layer 14 exposed by physical etching using argon Ar gas is removed by etching, so that the magnetic recording layer 14 formed of a continuous film is separated by the recesses 17 (FIG. 1 (f)). Subsequently, the carbon layer 15 on the magnetic recording layer 14 left by the separation is peeled off by reactive ion plasma using CF ₄ gas and oxygen gas (FIG. 1 (g)). Next, although not shown in the drawings, the magnetic recording layer 14 left by separation is used as a convex portion, and a nonmagnetic material is embedded in the concave portion 17 formed therebetween. At the time of this embedding, the nonmagnetic material deposited on the convex surface of the magnetic recording layer 14 is removed, and the surface is flattened based on the surface position of the magnetic recording layer 14. By depositing the carbon layer 15 again to form a carbon protective layer, a patterned media type magnetic recording medium is manufactured.

  As a publicly known document relating to a method for manufacturing such a patterned media type magnetic recording medium, a process for dividing a continuous recording layer into a number of divided recording elements in a vacuum chamber, a non-magnetic material filling process, a protective film forming process A method of manufacturing a discrete type magnetic recording medium efficiently by reliably preventing deterioration due to contamination or oxidation of the surface of the magnetic recording layer during the manufacturing process by consistently processing the magnetic recording medium, etc. Is known (Patent Document 1).

JP 2004-326831 A

As described in Patent Document 1, a hard mask layer such as a carbon layer is applied as a protective layer on a substrate having a magnetic recording layer made of a continuous film, and a resist layer is applied thereon, The process of surface unevenness applied to the magnetic recording medium substrate that is patterned on the resist layer by imprint method or electron beam exposure method and formed with an etching mask is continuously performed without returning to atmospheric pressure halfway with a round vacuum device. A manufacturing method is known. In this case, the surface unevenness processing step performed in the round type vacuum apparatus performs continuous processing by combining a reactive etching process using a fluorine-based gas or O ₂ gas and an ion etching process using an inert gas such as argon Ar. This is a manufacturing process. In such continuous processing, there is an advantage that it is possible to suppress foreign matter adhesion, unexpected oxidation, and moisture adhesion to the substrate surface that occurs when the pressure is returned to atmospheric pressure for each processing step. Further, in the etching process, in order to reduce the discharge stability and the processing time, the discharge is not continuous ON / OFF for each processing step but is continuously discharged.

  In this round type vacuum apparatus configuration, different process chambers are not installed in adjacent vacuum chambers in order to prevent the processing gas from flowing into other processes. That is, both sides of the process chamber are in a state of lower pressure (low vacuum pressure) than the process chamber and a pressure difference is generated between the process chamber. Therefore, the movement of the medium substrate to the next chamber is carried by opening the gate valve that partitions the chambers. However, since the vacuum pressure is lowered in the process chamber, the discharge becomes unstable, and the processed shape tends to vary when the imprinted substrate is processed.

  The present invention has been made in view of the above points. The purpose of the present invention is to prevent the deterioration of the substrate surface during the manufacturing process, suppress the variation in the processing shape and the loss time until the discharge is stabilized, and the processed pattern shape is stable and the patterned media has excellent reliability. Another object of the present invention is to provide a method for manufacturing a magnetic recording medium.

  In order to achieve the object of the present invention, the present invention provides a continuous vacuum apparatus after laminating at least metal underlayers 11, 12, 13, a magnetic recording layer 14, and a carbon layer 15 in this order on a nonmagnetic substrate 10. When at least one of the plurality of process processing vacuum chambers is connected to another process processing vacuum chamber via an adjacent pressure adjusting chamber Then, an inert gas is introduced into the adjacent pressure adjusting chamber, and the pressure in the adjacent pressure adjusting chamber is set to a pressure within ± 25% with respect to the pressure in the vacuum chamber for process processing.

  Further, at least the metal underlayers 11, 12, 13, the magnetic recording layer 14, and the carbon layer 15 are laminated in this order on the nonmagnetic substrate 10, and a resist pattern is formed on the surface of the carbon layer 15. And a step of pattern etching the carbon layer using the resist pattern as a mask in a vacuum chamber for process processing, a step of etching and separating the magnetic recording layer using the remaining carbon layer as a hard mask, When each of the steps to be peeled is sequentially processed, the vacuum chambers for process processing corresponding to the respective steps are connected to each other through the pressure adjusting chambers, respectively, and an inert gas is introduced into the pressure adjusting chambers. , Each process processing vacuum chamber adjacent to the pressure of each pressure adjustment chamber It may be a method for manufacturing a patterned magnetic recording medium according to the pressure within 25% ± relative bar pressure.

The inert gas is preferably argon gas. Further, it is desirable that the magnetic recording medium is a perpendicular magnetic recording medium.
The carbon layer of the present invention may be well known as a protective film for a magnetic recording medium such as a diamond-like carbon (DLC) film, and includes those containing hydrogen, nitrogen, and the like.

  According to the present invention, a patterned medium that prevents deterioration of the substrate surface during the manufacturing process, suppresses a variation in the processed shape and a loss time until the discharge is stabilized, stabilizes the processed pattern shape, and has excellent reliability. Can be provided.

It is board | substrate sectional drawing of the surface uneven | corrugated pattern formation process in a general patterned media type magnetic recording medium. It is a schematic block diagram of the round type vacuum apparatus concerning the manufacturing method of the patterned media type magnetic recording medium of this invention.

  Hereinafter, embodiments of a method for producing a patterned media type magnetic recording medium according to the present invention will be described in detail with reference to the drawings. The present invention is not limited to the description of the examples described below unless it exceeds the gist.

  FIG. 2 is a schematic configuration diagram of a round type vacuum apparatus according to the method for manufacturing a patterned media type magnetic recording medium of the present invention. The round vacuum apparatus has a structure in which a plurality of vacuum chambers respectively corresponding to a plurality of process steps are connected. In FIG. 2, a plurality of vacuum chambers are represented by rectangles with symbols such as L / UL, P1 to P19, C1 to C4, VTC, etc., depending on the application, and although not shown in the figure, they are all interconnected and not shown. The pressure is reduced by a vacuum pump. In addition, an opening / closing valve is provided at the connecting portion that connects the vacuum chambers, and the vacuum pressure of each of the chambers can be set individually. Hereinafter, the vacuum chamber may be abbreviated as a chamber. The L / UL chamber is a chamber serving as an inlet of a medium substrate carried into the apparatus and an outlet of a medium substrate that has undergone all the process processes in the apparatus. P1 to P19 are process chambers. C1 to C4 are corner chambers for changing the direction of the conveyor for moving the medium substrate by 90 degrees, and also have a function as a pressure adjusting chamber. VTC is a vacuum tunnel chamber for connecting the last process chamber P19 and the L / UL chamber.

  In the P1-P19 chamber, for example, P2 is used for the resist etching process, P4 is used for the carbon layer etching process, P6 is used for the magnetic recording layer etching process, P8 is used for the resist etching process, P10 is used for the carbon layer etching process, P11 Is used for the deuterium lamp irradiation process, P12 is used for the non-magnetic material embedding process in the recess, and P17, P18, and P19 are used for the carbon protective layer forming process. Process chambers other than the aforementioned process chambers are used as pressure adjusting chambers.

  The patterned media type magnetic recording medium according to the present invention comprises at least a metal underlayer such as a soft magnetic layer, a seed layer and an intermediate layer (Ru orientation layer), a magnetic recording layer comprising a continuous layer, and a carbon layer on a nonmagnetic substrate. Are prepared in this order, and a perpendicular magnetic recording medium substrate is prepared in which a resist pattern is formed to form a recess in the magnetic recording layer for separation. Carrying the perpendicular magnetic recording medium substrate into the round type vacuum apparatus, pattern-etching the carbon layer using the resist pattern as a mask, and patterning the magnetic recording layer using the formed carbon layer pattern as a mask In addition, a nonmagnetic material is filled in the recesses, and a carbon layer is formed again to form a protective layer.

  In detail, the formation of the perpendicular magnetic recording medium substrate on which the resist pattern is formed will be described. A plurality of magnetic recording medium substrates at a stage where a resist layer patterned by an imprint method is formed on the surface of the carbon layer is put in a cassette, and the load / unload (L / UL) of the round vacuum apparatus is carried out by a sputter load conveyor (not shown). Transport to chamber. For example, 25 magnetic recording medium substrates (hereinafter referred to as medium substrates) are collectively set in a sub chamber (not shown) in the L / UL chamber. When the sub-chamber is in a vacuum state, next, the medium substrate is transported through a plurality of connected vacuum process chambers so that each of the medium substrates can be processed one by one with a vacuum robot (not shown) in the L / UL chamber. For example, two sheets are placed side by side on the carrier. A carrier on which two medium substrates are placed side by side passes through an adjacent pressure adjusting chamber P1 and is conveyed to a process chamber P2 for resist etching. When the process process in the process chamber P2 is completed, the process is carried into the carbon layer etching chamber P4 through the C1 chamber and the pressure adjustment chamber P3, processed, and transferred to the next chamber. The processes after this carbon layer etching are also transferred to the next process chamber after the end of each process, and unloaded from the L / UL chamber through the last carbon protective layer forming chamber P19.

  The round type vacuum apparatus according to the present invention may be configured to include at least one vacuum process chamber for any process for discrete track media (DTM). Desirably, the structure shown in FIG. 2 to which the vacuum process chambers before and after that are connected is also preferable. In the following description of the embodiments, description will be made with reference to the apparatus shown in the schematic configuration diagram of FIG. The advantages obtained by the present invention will be described by taking the resist etching process in the P2 chamber as an example. In the following explanation, the carbon layer etching chamber P4, the magnetic recording layer etching process chamber P6, the resist etching process chamber P8, the carbon etching process chamber P10, the recess embedding process chamber P12, which are other processing process chambers, and the relationship between the adjacent chambers. Can be applied similarly.

  In the resist etching process in the P2 chamber, dry etching is performed under process conditions of a wait time of 10 seconds (standard) before waiting for discharge stabilization and an actual processing time of 15 seconds. The standard pressure of the P2 chamber is 0.1 Pa. In order to explain the effect of the production method of the present invention, the following experiment was conducted. By introducing the pressure of P1 and C1, which are adjacent to the resist etching chamber P2, into the respective chambers by 20 sccm of argon Ar gas, the opening of the pressure adjusting valve is 60%, 45%, 35%, 27%, Adjust to 6 types of 22% and 18%. At this time, the vacuum pressures of P1 and C1 are 25%, 50%, 75%, 100%, 125%, and 150% of the vacuum pressure of P2 of 0.1 Pa. That is, the media of Experimental Examples 1, 2, 3, 4, 5, and 6 corresponding to pressures of 0.025 Pa, 0.05 Pa, 0.075 Pa, 0.1 Pa, 0.125 Pa, and 0.15 Pa, respectively. The substrate sample was passed through and carried into the resist etching chamber P2, and a resist etching process was performed.

Furthermore, as a comparative example 1 according to the prior art, an example is performed in which the resist etching process is performed under the condition that the argon Ar gas is not introduced into the adjacent chambers P1 and C1 and the high vacuum pressure is maintained. The vacuum pressure of P1 and C1 at this time is 1 × 10 ⁻⁵ Pa. Under the pressure conditions of the adjacent chambers P1 and C1, the previous wait time during processing in the resist etching chamber P2 is changed to 0 seconds, 2 seconds, 4 seconds, 6 seconds, 8 seconds, and 10 seconds (standard), Three magnetic recording medium substrates (hereinafter referred to as medium substrates) are processed under the same conditions for each condition. The height of the convex portion of the resist on each medium substrate is measured to confirm the processing stability. The height of the convex portion was measured with an AFM (atomic force microscope). The favorable processing state in the resist etching process is that the height of the convex portion of the resist is 20 nm or more and the variation due to processing is within 2.5%.

  Table 1 shows the difference (variation) in the height of the convex portions of the resist when the previous Wait time and the pressure in the adjacent chamber were changed in Comparative Example 1 and Experimental Examples 1 to 6. The difference (variation) in the height of the convex portion was calculated as (convex portion Max−Min) / (Max + Min) × 100 (%) for three media substrates processed under the same conditions. Table 2 shows the average of the convex part heights (nm) of the resists of the three media substrates processed under the same conditions.

  Comparative Example 1 which is a conventional technique in which the pressure adjusting chamber P1 and the corner chamber C1 are kept in a high vacuum without pressure adjustment, and Argon Ar gas is introduced to adjust the pressure, and Experimental Example 1 from low pressure to 0.050 Pa, In Experimental Example 6 of 2 and 0.150 Pa or higher, the variation (%) is large compared with Experimental Examples 3 to 5 as a whole from Table 1, but it shows that the longer the previous Wait time, the smaller the variation. . However, in Experimental Examples 3 to 5, the variation is within 2.5% after the previous wait time of 4 seconds (10 seconds in the prior art) or more, indicating that the variation is small. Also, from Table 2, it can be seen that in Experimental Examples 3 to 5, the height of the convex portion can be secured to 20 nm or more when the previous wait time is 4 seconds or more (10 seconds in the prior art).

  From the above explanation, if the pressure in the adjacent chamber is adjusted to within ± 25% of the pressure in the process chamber and the previous wait time is set to 4 seconds or more, the reliability of processing is improved, and the pressure before adjusting the pressure in the adjacent chamber is not performed. Compared to the case where the wait time is 10 seconds, the variation and the height of the convex portion are equivalent even if the tact time is shortened. Therefore, it can be seen that if the pressure adjustment of the adjacent chamber is ± 25% with respect to the pressure of the process chamber, it is effective for processing stability and the tact time can be shortened from 10 seconds to 4 seconds or more.

  As described above, according to the method for producing a patterned media type magnetic recording medium of the present invention, at least a metal underlayer such as a soft magnetic layer, a seed layer, and an intermediate layer (Ru orientation layer) on a nonmagnetic substrate, A resist layer is formed on a substrate provided with a carbon layer as a magnetic recording layer and a hard mask layer. A pattern is formed on the resist layer by imprinting or electron beam exposure. The medium substrate at this stage is carried into a round type vacuum apparatus, and the subsequent processes are performed in the round type vacuum apparatus. The medium substrate carried into the vacuum apparatus is transferred to the process chamber through an adjacent chamber into which argon Ar gas within ± 25% of the pressure of the process chamber is introduced. When the processing of this process chamber is completed, the next process is performed through the next adjacent chamber into which argon Ar gas within ± 25% of the pressure of the next process chamber is introduced in the same manner as described above in order to transfer to the next process chamber. It is transferred to the chamber. Inside, the carbon layer is scraped using the resist pattern as a mask to expose the magnetic recording layer. In the subsequent transfer to the process chamber, argon Ar gas having a pressure within ± 25% of the pressure of the next process chamber is similarly introduced. In this manner, by introducing argon Ar gas whose pressure in the adjacent chamber is within ± 25% of the pressure in the next process chamber, for example, in the resist process chamber, the wait time before processing is set to 4 seconds or more. As a result, the height of the convex portion of the magnetic recording layer after processing is ensured to be 20 nm or more, highly stable etching processing within which variation is kept within 2.5%, and patterned media type magnetic recording with excellent reliability. A method for manufacturing a medium can be provided.

DESCRIPTION OF SYMBOLS 10 ... Nonmagnetic board | substrate 11 ... Soft magnetic layer 12 ... Seed layer 13 ... Intermediate | middle layer (Ru orientation layer)
14 ... magnetic recording layer 15 ... carbon layer 16 ... resist 17 ... concave

Claims (4)

After laminating at least a metal underlayer, a magnetic recording layer, and a carbon layer in this order on a nonmagnetic substrate, the plurality of processes are carried into a continuous vacuum apparatus and processed in a plurality of process processing vacuum chambers. At least one of the processing vacuum chambers is connected to another process processing vacuum chamber via an adjacent pressure adjusting chamber, and an inert gas is introduced into the adjacent pressure adjusting chamber, and the adjacent pressure adjustment is performed. A method for producing a patterned media type magnetic recording medium, characterized in that the pressure in the chamber is within ± 25% of the pressure in the vacuum chamber for processing. After laminating at least a metal underlayer, a magnetic recording layer, and a carbon layer in this order on a nonmagnetic substrate, and forming a resist pattern on the surface of the carbon layer, it is carried into a continuous vacuum device, and in a vacuum chamber for process processing, When sequentially processing the step of pattern etching the carbon layer using the resist pattern as a mask, the step of etching and separating the magnetic recording layer using the remaining carbon layer as a hard mask, and the step of peeling the carbon layer, respectively. Process processing vacuum chambers corresponding to the respective steps are connected to each other via adjacent pressure adjusting chambers, an inert gas is introduced into the adjacent pressure adjusting chambers, and The pressure relative to the pressure of each adjacent process vacuum chamber Method of manufacturing a patterned magnetic recording medium, characterized in that a pressure of up to 25%. 2. The method for producing a patterned media type magnetic recording medium according to claim 1, wherein the inert gas is an argon gas. 3. The method of manufacturing a patterned media type magnetic recording medium according to claim 1, wherein the magnetic recording medium is a perpendicular magnetic recording medium.

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