Patent Publication Number: US-2010108495-A1

Title: Thin film formation apparatus and magnetic recording medium manufacturing method

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a thin film formation apparatus and magnetic recording medium manufacturing method. 
     2. Description of the Related Art 
     Recently, magnetic recording media are being extensively researched and developed as means for recording enormous amounts of information. Presently, a recording method called “perpendicular recording method” that records signals by pointing magnetization vectors in the direction perpendicular to the in-plane direction of a recording layer is being mass produced. 
     In the magnetic recording media, a Co—Cr-based alloy is mainly used as a recording layer. 
     The recording layer (magnetic recording film) of the magnetic recording medium is required to have high magnetic anisotropy to maintain thermal stability of written information. Materials having high magnetic anisotropy are expected to be used in thermally assisted magnetic recording where the medium is heated while switching magnetic domains. Heating the medium reduces the coercivity and facilitates bit writing. Bit-patterned media, in which dot patterns are artificially and regularly arranged, need to be formed out of high anisotropy materials as well for thermal stability. Examples of promising materials having high magnetic anisotropy are alloys of Co and Fe such as CoPt, FePt, and CoFePt which require high deposition temperatures to obtain the high anisotropy ordered structures. 
     To form a recording layer having high magnetic anisotropy, the substrate temperature must be raised and controlled at a predetermined temperature. For example, a thin-film stack manufacturing apparatus disclosed in Japanese Patent Laid-Open No. 2008-176847 includes a plurality of chambers, and a heating means for heating a film formation substrate. The substrate is sequentially transferred into the individual chambers, and a plurality of thin films are stacked on the substrate by sputtering. A plurality of substrates is simultaneously accommodated in the many chambers. While a thin film is being formed on a substrate, the heating means heats another substrate waiting for film deposition. 
     Unfortunately, the thin-film stack manufacturing apparatus disclosed in Japanese Patent Laid-Open No. 2008-176847 has the problem that uniform temperature control cannot be performed while a film is formed on a film formation substrate (i.e., during film formation). Moreover, after heating, the substrate temperature immediately drops as it is transported for sputtering especially when the needed temperatures are very high (&gt;400° C.). 
     The thin-film stack manufacturing apparatus disclosed in Japanese Patent Laid-Open No. 2008-176847 also requires a large chamber as a separate heater is provided in parallel to the targets. 
     SUMMARY OF THE INVENTION 
     The present invention provides a magnetic recording medium manufacturing technique capable of sustaining the temperature of the substrate for the deposition of high anisotropy alloys by allowing uniform temperature control during deposition. 
     According to the first aspect of the present invention, there is provided a thin film formation apparatus which includes a plurality of chambers, and performs processing for forming thin films on two surfaces of a substrate transferred to the plurality of chambers, wherein a first sputtering chamber of the plurality of chambers includes a first sputtering film formation unit configured to perform a sputtering film formation process on a first surface of the substrate, and a first heating unit configured to heat a second surface opposite to the first surface of the substrate, and a second sputtering chamber of the plurality of chambers includes a second heating unit configured to heat the first surface of the substrate having undergone the sputtering film formation process performed by the first sputtering chamber, and a second sputtering film formation unit configured to perform a sputtering film formation process on the second surface of the substrate heated by the first sputtering chamber. 
     According to the second aspect of the present invention, there is provided a thin film formation apparatus which includes a plurality of chambers, and performs processing for forming thin films on two surfaces of a substrate transferred to the plurality of chambers, wherein a first sputtering chamber of the plurality of chambers includes a first target accommodating unit configured to accommodate a first target for performing a film formation process on a first surface of the substrate, a first heating unit formed to surround a periphery of the first target, and configured to heat the first surface of the substrate, a second heating unit configured to heat a second surface opposite to the first surface of the substrate, and a second target accommodating unit formed to surround a periphery of the second heating unit, and configured to accommodate a second target for performing a film formation process on the second surface of the substrate, and a second sputtering chamber of the plurality of chambers includes a third heating unit configured to heat the first surface of the substrate, a third target accommodating unit formed to surround a periphery of the third heating unit, and configured to accommodate a third target for performing a film formation process on the first surface, a fourth target accommodating unit configured to accommodate a fourth target for performing a film formation process on the second surface of the substrate, and a fourth heating unit formed to surround a periphery of the fourth target accommodating unit, and configured to heat the second surface of the substrate. 
     According to the third aspect of the present invention, there is provided a magnetic recording medium manufacturing method including a heating step of heating a substrate to a predetermined temperature, and a film formation step of forming a film on the substrate heated in the heating step, wherein the above thin film formation apparatus is used in the heating step and the film formation step. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exemplary sectional view showing an example of a magnetic recording medium manufactured by a magnetic recording medium manufacturing method according to an embodiment of the present invention. 
         FIG. 2  is a view showing an example of a thin film formation apparatus (magnetic recording medium manufacturing apparatus) according to the embodiment of the present invention. 
         FIG. 3  is a view for explaining chambers of the thin film formation apparatus (magnetic recording medium manufacturing apparatus) according to the embodiment of the present invention. 
         FIG. 4  is a sectional view for explaining the chambers of the thin film formation apparatus (magnetic recording medium manufacturing apparatus) according to the embodiment of the present invention. 
         FIG. 5  is a flowchart for explaining the magnetic recording medium manufacturing method according to the embodiment of the present invention. 
         FIG. 6  is a view showing a modification of the thin film formation apparatus (magnetic recording medium manufacturing apparatus) shown in  FIG. 2 . 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Preferred embodiments of the present invention will exemplarily be explained in detail below with reference to the accompanying drawings. Note that constituent elements described in the embodiments are merely examples, and the technical scope of the present invention is determined by the scope of the appended claims and is not limited by the following individual embodiments. 
     First, a magnetic recording medium as an example of a thin-film stack manufactured by a magnetic recording medium manufacturing apparatus and magnetic recording medium manufacturing method according to an embodiment of the present invention will be explained. Note that in this specification, the term “magnetic recording medium” is not limited to a magnetic disk such as a hard disk or a floppy (registered trademark) disk using only magnetism when recording and reading information. For example, a “magnetic recording medium” includes a magnetooptical recording medium such as an MO (Magneto Optical) disk using both magnetism and light, or a thermally assisted recording medium using both magnetism and heat. 
       FIG. 1  is an exemplary sectional view showing an example of a magnetic recording medium (thin-film stack) manufactured by the magnetic recording medium manufacturing apparatus and magnetic recording medium manufacturing method according to the embodiment of the present invention. In this embodiment, an ECC (Exchange-Coupled Composite) medium obtained by improving a perpendicular recording medium will be explained as an example of the magnetic recording medium. However, the spirit and scope of the present invention are not limited to this example. For example, the magnetic recording medium may also be a general perpendicular recording medium, longitudinal recording medium, bit-patterned medium, or thermally assisted recording medium. 
     As shown in  FIG. 1 , the magnetic recording medium includes a substrate  100 , and a first soft magnetic layers  101   a,  spacer layer  102 , second soft magnetic layer  101   b,  seed layer  103 , magnetic layer  104 , exchange coupling control layer  105 , third soft magnetic layer  106 , and protective layer  107  sequentially stacked on one or both of the two surfaces of the substrate  100 . 
     As the material of the substrate  100 , it is possible to use a nonmagnetic material generally used as a magnetic recording medium substrate. Examples are glass, an Al alloy having a NiP plating film, ceramics, a flexible resin, and Si. In this embodiment, the substrate  100  is a disk-like member having a central hole. However, the present invention is not limited to this, and a rectangular member or the like may also be used. 
     The first soft magnetic layer  101   a  formed on the substrate  100  is a layer formed to improve the recording/reproduction characteristics by controlling the magnetic flux from a magnetic head for use in magnetic recording. However, the first soft magnetic layer  101   a  may also be omitted. As the constituent material of the first soft magnetic layer  101   a,  it is possible to use, e.g., CoZrNb, CoZrTa, or FeCoBCr in accordance with the film formed immediately above the first soft magnetic layer  101   a.    
     As the material of the spacer layer  102 , it is possible to use, e.g., Ru or Cr. The second soft magnetic layer  101   b  formed on the spacer layer  102  is identical to the first soft magnetic layer  101   a.  The first soft magnetic layer  101   a,  spacer layer  102 , and second soft magnetic layer  101   b  form a soft underlayer. 
     The seed layer  103  formed on the soft underlayer is a layer formed immediately below the magnetic layer  104  in order to suitably control the crystal orientation, crystal grain size, grain size distribution, and grain boundary segregation of the magnetic layer  104 . As the material of the seed layer  103 , it is possible to use, e.g., MgO, Cr, Ru, Pt, or Pd. 
     A magnetic recording layer  5  includes the magnetic layer  104  having a large anisotropy Ku value, the exchange coupling control layer  105 , and the third soft magnetic layer  106  having a small Ku value. 
     The magnetic layer  104  formed on the seed layer  103  and having a large Ku value affects the overall Ku value of the magnetic recording layer  5 , so a material having a maximum possible Ku value is used. As the material of the magnetic layer  104 , it is possible to use a material having an easy magnetization axis perpendicular to the substrate surface, and having a structure in which ferromagnetic grains are isolated by the nonmagnetic grain boundary component of an oxide. For example, it is possible to use a material obtained by adding an oxide to a ferromagnetic material containing at least CoPt. Examples are CoPtCr—SiO 2  and CoPt—SiO 2 . It is also possible to use Co 50 Pt 50 , Fe 50 Pt 50 , or Co 50-y Fe y Pt 50 . 
     The exchange coupling control layer  105  formed on the magnetic layer  104  contains a crystalline metal or alloy, and an oxide. As the material of the crystalline metal or alloy, it is possible to use, e.g., Pt, Pd, or an alloy of Pt or Pd. As the crystalline alloy, it is also possible to use, e.g., an alloy of an element selected from Co, Ni, and Fe and a nonmagnetic metal. 
     The strength of the exchange coupling force between the magnetic layer  104  and third soft magnetic layer  106  can most simply be controlled by changing the film thickness of the exchange coupling control layer  105 . The film thickness of the exchange coupling control layer  105  is, e.g., 0.1 to 2.0 nm. 
     The third soft magnetic layer  106  formed on the exchange coupling control layer  105  mainly functions to reduce the magnetization reversing magnetic field, so a material having a minimum possible Ku value is used. As the material of the third soft magnetic layer  106 , it is possible to use, e.g., Co, NiFe, or CoNiFe. 
     The protective layer  107  formed on the third soft magnetic layer  106  is formed to prevent damage caused by the contact between a head and the medium surface. As the material of the protective layer  107 , it is possible to use, e.g., a single component such as C, SiO 2 , or ZrO 2 , or a material obtained by adding an additive element to C, SiO 2 , or ZrO 2  as a main component. 
     A thin-film formation apparatus (to be also referred to as a “magnetic recording medium manufacturing apparatus” hereinafter) used in the magnetic recording medium manufacturing method according to the embodiment of the present invention will be explained below.  FIG. 2  is an exemplary view showing an example of the magnetic recording medium manufacturing apparatus according to the embodiment of the present invention.  FIG. 3  is an exemplary view for explaining chambers  209 ,  210 ,  211 , and  213  of the magnetic recording medium manufacturing apparatus.  FIG. 4  is an exemplary sectional view for explaining the chamber  210  of the magnetic recording medium manufacturing apparatus.  FIG. 5  is a flowchart for explaining the magnetic recording medium manufacturing method. 
     In the magnetic recording medium manufacturing apparatus as shown in  FIG. 2 , a load lock chamber  81  for loading the substrate  100  ( FIG. 1 ) on a carrier  2 , an unload lock chamber  82  for unloading the substrate  100  from the carrier  2 , and a plurality of chambers  201 ,  202 ,  203 ,  204 ,  205 ,  206 ,  207 ,  208 ,  209 ,  210 ,  211 ,  212 ,  213 ,  214 ,  215 ,  216 ,  217 , and  218  are arranged along the contours of a rectangle. Also, a transfer path is formed along the load lock chamber  81 , chambers  201  to  218 , and unload lock chamber  82 . The transfer path has a plurality of carriers  2  capable of carrying the substrate  100 . In each chamber, a processing time (tact time) required for the processing of the substrate  100  is predetermined. When this processing time (tact time) has elapsed, the substrates  100  carried by the carriers  2  are sequentially transferred to the next chambers. 
     For the magnetic recording medium manufacturing apparatus to process about 1,000 substrates per hour, the tact time in one chamber is about 5 sec or less, preferably, about 3.6 sec or less. 
     Each of the load lock chamber  81 , unload lock chamber  82 , and chambers  201 ,  202 ,  203 ,  204 ,  205 ,  206 ,  207 ,  208 ,  209 ,  210 ,  211 ,  212 ,  213 ,  214 ,  215 ,  216 ,  217 , and  218  is a vacuum chamber that can be evacuated by a dedicated or shared evacuating system. Gate valves (not shown) are formed in the boundary portions between the load lock chamber  81 , unload lock chamber  82 , and chambers  201 ,  202 ,  203 ,  204 ,  205 ,  206 ,  207 ,  208 ,  209 ,  210 ,  211 ,  212 ,  213 ,  214 ,  215 ,  216 ,  217 , and  218 . 
     More specifically, the chamber  201  of the magnetic recording medium manufacturing apparatus is a chamber for forming the first soft magnetic layer  101   a  on the substrate  100 . The direction change chamber  202  is a chamber for changing the transfer direction of the carrier  2 . The chamber  203  is a chamber for forming the spacer layer  102  on the first soft magnetic layer  101   a.  The chamber  204  is a chamber for forming the second soft magnetic layer  101   b  on the spacer layer  102 . The chamber  205  is a chamber for forming the seed layer  103  on the second soft magnetic layer  101   b.  The direction change chamber  206  is a chamber for changing the transfer direction of the carrier  2 . The chamber  207  (a first heating chamber) and the chamber  208  (a second heating chamber) are preheating chambers for preheating the substrate  100 . Note that the seed layer  103  can also be formed in the chamber  209 . 
     The chambers  210  and  211  are chambers capable of functioning as sputtering modules for forming the magnetic layer  104  on the seed layer  103 . The direction change chamber  212  is a chamber for changing the direction of the carrier  2 . The cooling chamber  213  is a chamber for cooling the substrate  100 . The chamber  214  is a chamber for forming the exchange coupling control layer  105  on the magnetic layer  104 . The chamber  215  is a chamber for forming the third soft magnetic layer  106  on the exchange coupling control layer  105 . The direction change chamber  216  is a chamber for changing the direction of the carrier  2 . The chambers  217  and  218  are chambers for forming the protective layer  107 . 
       FIG. 3  is a view for explaining details of the chamber  209  for forming the seed layer  103 , the chambers  210  and  211  functioning as sputtering modules for forming the magnetic layer  104 , and the cooling chamber  213  for cooling the substrate in the magnetic recording medium manufacturing apparatus shown in  FIG. 2 . Referring to  FIG. 3 , the arrow indicates the substrate transfer direction. Note that the direction change chamber  212  shown in  FIG. 2  is not shown in  FIG. 3 , as it is not a chamber for processing the substrate. 
     Referring to  FIG. 3 , the front surface (first surface) of the substrate  100  is surface A, and the rear surface (second surface) of the substrate  100 , which is opposite to (faces) surface A, is surface B. In the arrangement shown in  FIG. 3 , the substrate  100  is clamped from the edges. Referring to  FIG. 3 , “a” attached to each reference numeral indicates the arrangement on the surface A side, and “b” indicates that on the surface B side. 
     In the chamber  209  for forming the seed layer  103 , targets  41   a  and  41   b  are installed to face each other. This makes it possible to form the seed layers  103  on the two surfaces of the substrate  100 . As the target material for forming the seed layers  103 , it is possible to use, e.g., Co 50 Pt 50 , Fe 50 Pt 50 , or Co 50-y Fe y Pt 50 . Note that a turbo molecular pump (to be referred to as a “TMP” hereinafter)  31  for evacuating a chamber is connected to each of the chambers  209 ,  210 ,  211 , and  213 . 
     Next, the chambers  210  and  211  functioning as sputtering modules for forming the magnetic layer  104  will be explained in detail below as the feature of the present invention. 
     The chamber  210  forms the magnetic layers  104  on the substrate by sputtering target materials set in the chamber  210 . 
     On the first surface side (surface A side), the chamber  210  includes a first target accommodating unit (table) for accommodating a first target  42   a  for forming the magnetic layer  104  on the substrate, and a heating unit  52   a  (first heating unit) that is formed to surround the periphery of the first target and heats the substrate. 
     Also, on the second surface side (surface B side) opposite to the first surface side (surface A side), the chamber  210  includes a heating unit  52   b  (second heating unit) that is formed to face the first target accommodating unit and heats the substrate, and a second target accommodating unit (table) that is formed to surround the periphery of the heating-unit  52   b  (second heating unit), and accommodates a second target  42   b  for forming the magnetic layer  104  on the substrate. 
     The chamber  211  connected to the chamber  210  forms the magnetic layers  104  on the substrate by sputtering target materials set in the chamber  211 . 
     On the first surface side (surface A side), the chamber  211  includes a heating unit  53   a  (third heating unit) for heating the substrate, and a third target accommodating unit (table) that is formed to surround the periphery of the heating unit  53   a  (third heating unit), and accommodates a third target  43   a  for forming the magnetic layer  104  on the substrate. 
     Also, on the second surface side (surface B side) opposite to the first surface side (surface A side), the chamber  211  includes a fourth target accommodating unit (table) that is formed to face the heating unit  53   a  (third heating unit), and accommodates a fourth target  43   b  for forming the magnetic layer  104  on the substrate, and a heating unit  53   b  (fourth heating unit) that is formed to surround the periphery of the fourth target accommodating unit (table), and heats the substrate. 
     The first target  42   a  and the fourth target  43   b  are formed to have almost identical disk shapes, and the heating unit  52   a  (first heating unit) and the heating unit  53   b  (fourth heating unit) are formed to have almost identical ring shapes. 
     The second target  42   b  and the third target  43   a  are formed to have almost identical ring shapes, and the heating unit  52   b  (second heating unit) and the heating unit  53   a  (third heating unit) are formed to have almost identical disk shapes. 
     The heating unit  52   a  (first heating unit) heats a region corresponding to the third target accommodating unit accommodating the third target  43   a.  The heating unit  52   b  (second heating unit) heats a region corresponding to the fourth target accommodating unit accommodating the fourth target  43   b.    
     The heating unit  53   a  (third heating unit) heats a region corresponding to the first target accommodating unit accommodating the first target  42   a.  The heating unit  53   b  (fourth heating unit) heats a region corresponding to the second target accommodating unit accommodating the second target  42   b.    
     In the chamber  210 , the heating unit  52   a  is placed in a position where it primarily heats the outer periphery of the substrate, and the heating unit  52   b  is placed in a position where it mainly heats the central portion of the substrate. The entire substrate can be heated by thus arranging the heating units  52   a  and  52   b.  This makes it possible to raise or maintain the temperature of the substrate and its uniformity while depositing the magnetic alloys. 
     Also, in the chamber  211 , the heating unit  53   b  is placed in a position where it heats the outer periphery of the substrate, and the heating unit  53   a  is placed in a position where it heats the central portion of the substrate. By thus arranging the heating units  53   a  and  53   b,  the entire substrate can be heated from portions different from the portions heated in the chamber  210 . This makes it possible to perform uniform temperature control on the substrate surfaces while performing magnetic layer deposition. 
     In the two chambers  210  and  211 , the magnetic layer  104  having a uniform film thickness can be formed on surface A of the substrate by sputtering from the first target  42   a  having a small diameter and the ring-like third target  43   a  having a larger diameter. Likewise, the magnetic layer  104  having a uniform film thickness can be formed on surface B of the substrate by sputtering from the fourth target  43   b  having a small diameter and the ring-like second target  42   b  having a larger diameter. Sputtering from the smaller target results in a thicker film near the middle of the substrate whereas sputtering from the larger annular target results in a film that is thicker near the substrate outer diameter. By judiciously adjusting the rates, a uniform magnetic film is formed on the entire substrate on both faces. 
     Note that as the “heating unit” herein mentioned, it is possible to use, e.g., a heater, block heater, or lamp heater. The efficiency of a lamp heater would be affected by deposition. Thus, a block heater may provide more repeatable temperatures even with deposition on its surface. 
     The above-mentioned magnetic layer material can be used as the first target  42   a,  third target  42   b,  second target  43   a,  and fourth target  43   b.  For example, it is possible to use a material obtained by adding an oxide to a ferromagnetic material containing at least CoPt. Examples are CoPtCr—SiO 2  and CoPt—SiO 2 . It is also possible to use Co 50 Pt 50 , Fe 50 Pt 50 , or Co 50-y Fe y Pt 50 . 
       FIG. 4  is a schematic sectional view showing the chamber  210  in the substrate transfer direction (the substrate transfer direction is perpendicular to the drawing surface). The surface of the first target  42   a  which faces the substrate and the surface of the heating unit  52   b  (second heating unit) which faces the substrate are arranged in positions that are almost symmetrical with respect to the substrate. Similarly, the surface of the first heating unit  52   a  which faces the substrate and the surface of the second target  42   b  which faces the substrate are arranged in positions almost symmetrical with respect to the substrate. Note that a magnet unit  420   a  is installed at the back of the first target  42   a,  and a magnet unit  420   b  is installed at the back of the second target  42   b.    
     In the chamber  210 , the magnet unit  420   a  functions as a first sputtering unit for executing sputtering by generating magnetic fields while the target is held at a predetermined voltage. The magnet unit  420   b  functions as a second sputtering unit for executing sputtering by generating magnetic fields while the target is held a predetermined voltage. A magnet unit is installed at the back of the third target  43   a  in the chamber  211  as well. This magnet unit functions as a third sputtering unit for executing sputtering by generating magnetic fields while the target is held at a predetermined voltage. In addition, a magnet unit is installed at the back of the fourth target  43   b.  This magnet unit functions as a fourth sputtering unit for executing sputtering by generating magnetic fields while the target is held at a predetermined voltage. 
     The surfaces of the first target  42   a  and heating unit  52   a  which face the substrate are parallel but not necessarily on the same plane. Likewise, the surfaces of the second target  42   b  and heating unit  52   b  which face the substrate are parallel but not necessarily on the same plane. 
     For the magnetic recording medium manufacturing apparatus to process about 1,000 substrates per hour, the tact time in one chamber must be shortened to about 5 sec or less, desirably, about 3.6 sec or less as described previously. To achieve a heating process (temperature control) for heating the substrate to a desired temperature (about 400° C. to 600° C.) while the tact time is thus limited, the surfaces of the heating units  52   a  and  52   b  are arranged at a distance of, e.g., 50 mm or less, preferably, 30 mm or less from the substrate surface. 
     Referring to  FIG. 3  again, the cooling chamber  213  includes cooling mechanisms  61   a  and  61   b  facing each other, in order to cool the two surfaces of the substrate on which the magnetic layers  104  are formed. The two surfaces of the substrate, having the magnetic layers  104  formed while heating to a desired temperature in the chambers  210  and  211 , are cooled by the cooling mechanism  61   a  (first cooling mechanism) and cooling mechanism  61   b  (second cooling mechanism) in the cooling chamber  213 . The cooling process is needed to obtain the optimum temperature for later deposition of the protective layers  107 , e.g., to about 200° C. or less. 
     As explained above, this embodiment can provide a magnetic recording medium manufacturing apparatus (sputtering apparatus) capable of maintaining or raising the substrate temperature during high anisotropy layer deposition as well as achieving temperature uniformity on the substrate. 
     Next, a magnetic recording medium manufacturing method using the magnetic recording medium manufacturing apparatus according to the embodiment of the present invention will be explained below with reference to  FIGS. 1 and 5 . 
     In step S 501 , a substrate is carried into the load lock chamber  81 , and loaded as it is placed on the carrier  2  by a substrate transfer robot (not shown). 
     In step S 502 , the substrate is heated to a predetermined temperature T 1  (about 100° C.) in the load lock chamber  81 , thereby removing contaminants and water sticking to the substrate. 
     In step S 503 , soft underlayers are formed. More specifically, first soft magnetic layers  101   a  are formed in the chamber  201 , spacer layers  102  (the thickness is 0.7 to 2 nm) are formed in the chamber  203 , and second soft magnetic layers  101   b  are formed in the chamber  204 . 
     In step S 504 , the substrate is sequentially transferred to the chamber  207  (first heating chamber) and chamber  208  (second heating chamber), and heated to a temperature T 2  (about 400° C. to 700° C.) higher than the temperature T 1  (about 100° C.) in step S 502 . This step is in preparation for achieving magnetic layers  104  of high magnetic anisotropy. In the magnetic recording medium manufacturing apparatus, the processing time (tact time) in one chamber is limited in order to increase the throughput. In the chambers  210  and  211  for forming magnetic layers  104 , it is difficult to heat the substrate to a temperature required to increase the magnetic anisotropy of magnetic layers  104  within the limited time. Therefore, the magnetic recording medium manufacturing apparatus includes the chamber  207  (first heating chamber) and chamber  208  (second heating chamber) for preheating (preliminary heating). In the magnetic recording medium manufacturing apparatus, the chamber  207  (first heating chamber) and the chamber  208  (second heating chamber) function as preliminary heating units. 
     Since the substrate temperature decreases before the substrate is transferred to the chamber  210  for forming magnetic layers  104 , the substrate must be heated (preliminarily heated) in the chamber  207  (first heating chamber) and chamber  208  (second heating chamber) to a temperature equal to or higher than the temperature required to increase the magnetic anisotropy in the chamber  210 . If the substrate made of glass is overheated, however, it may plastically deform rendering it useless as a rigid disk medium. Moreover, it could fall from the carrier  2  and adversely affect the operation of the entire tool. In the chamber  207  (first heating chamber) and chamber  208  (second heating chamber), therefore, the glass substrate is heated to a temperature below the plastic deformation temperature. 
     In step S 505 , seed layers  103  are formed to suitably control the crystal characteristics of magnetic layers  104 . Note that the seed layers  103  may also be formed in the chamber  205  before the heating step in step S 504 . 
     In step S 506 , the substrate is transferred to the chambers  210  and  211  for forming magnetic layers  104 , and magnetic layers  104  are formed while the substrate is heated to a predetermined temperature T 3  (about 400° C. to 600° C.). In this step, the magnetic layers  104  are formed while the substrate is uniformly heated in the chamber  210  as described previously. 
     In step S 507 , the substrates are sequentially transferred to the cooling chamber  213  and cooled to a temperature optimum for the formation of protective layers  107 . When using carbon as the material of the protective layers  107 , the substrate must be cooled to, e.g., about 200° C. or less. 
     Subsequently, in step S 508 , the substrate is transferred to the chambers  217  and  218  for CVD, where the protective layers  107  may be formed. 
     Note that ultra-thin exchange coupling control layers  105  may also be formed between the magnetic layers  104  and protective layers  107  in the chamber  214 . Note also that third soft magnetic layers  106  may also be formed in the chamber  215  after the substrate is cooled and before the protective layers  107  are formed. 
     In step S 509 , the substrate is unloaded as it is removed from the carrier  2  in the unload lock chamber  82 . 
     As explained above, this embodiment can provide a magnetic recording medium manufacturing method capable of performing temperature control on substrate surfaces. 
     (Modification) 
       FIG. 6  is a view showing a modification of the arrangement of the thin film formation apparatus (magnetic recording medium manufacturing apparatus) shown in  FIG. 2 . The magnetic recording medium manufacturing apparatus shown in  FIG. 6  includes chambers  250  and  251  instead of the chambers  210  and  211  shown in  FIG. 2 . Note that the same reference numerals as in  FIG. 2  denote the same parts, and a repetitive explanation will be omitted. Note also that in the magnetic recording medium manufacturing apparatus shown in  FIG. 6 , a load lock chamber  81 , chambers  201  to  207 ,  212 ,  214 ,  216 , and  218 , and an unload lock chamber  82  are not shown for the sake of illustrative simplicity. 
     As shown in  FIG. 6 , the chamber  250  includes a heating unit  611   a  installed on the surface B side of a substrate, and a sputtering film formation unit (first sputtering film formation unit) installed on the surface A side of the substrate and including a target  601   b  and magnet unit (not shown) for performing a sputtering film formation process. When processing surface B (a second surface) of the substrate in the chamber  250 , the heating unit  611   a  heats the substrate from surface A (a first surface) of the substrate, which is opposite to surface B. In this arrangement, a sputtering film formation process can be performed while the substrate is uniformly heated. 
     The chamber  250  functions as a first sputtering chamber, and connects to the chamber  251  functioning as a second sputtering chamber. 
     The chamber  251  includes a heating unit  612   b  installed on the surface A side of the substrate, and a sputtering film formation unit (second sputtering film formation unit) installed on the surface B side of the substrate and including a target  602   a  and magnet unit (not shown) for performing a sputtering film formation process. When processing surface A (the first surface) of the substrate in the chamber  251 , the heating unit  612   b  heats the substrate from its surface B (the second surface), which is opposite to surface A. In this arrangement, a sputtering film formation process can be performed while the substrate surface that is not heated in the chamber  250  is uniformly heated in the chamber  251 . 
     When forming magnetic recording layers having magnetic anisotropy, the magnetic recording medium manufacturing apparatus shown in  FIG. 6  can perform a sputtering film formation process while uniformly heating the substrate surfaces with a simpler arrangement. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2008-282384 filed on Oct. 31, 2008, which is hereby incorporated by reference herein in its entirety.