Substrate-Holder, Etching Method of the Substrate, and the Fabrication Method of a Magnetic Recording Media

CLAIM OF PRIORITY

The present invention claims priority from Japanese application JP 2006-343470 filed on Dec. 20, 2006, the content of which is hereby incorporated by reference into this application.

FIELD OF THE INVENTION

The present invention relates to a substrate-holder, an etching method of the substrate, and the fabrication method of a magnetic recording media, and more particularly to a substrate-holder and an etching method of a substrate which are suited for fabricating the magnetic recording media in which a recording layer is formed in a concavo-convex pattern.

BACKGROUND OF THE INVENTION

A hard disk device rotates a disk-shaped magnetic recording media at a high speed, and records and reproduces a digital signal by means of a magnetic head. Up to now, the magnetic recording media as used is made by depositing a magnetic material on a disk-shaped aluminum substrate or hardened glass substrate, whose surface is very flat, through sputtering. With an increase in the recording density, an attempt has been made to improve a surface recording density by microparticulating the magnetic material that constitutes the recording layer, changing the recording density, devising a laminate structure of the magnetic material, or applying a vertical recording system. Hence, a limit of an improvement in the recording media has begun to appear in the existing recording media due to a problem such as noises, crosstalk, or thermal fluctuation resistance which is attributable to the media. Under the circumstances, there has been proposed a magnetic recording media or a recording media such as a so-called discrete track media or a patterned media, which can realize a further improvement in the recording density with the provision of given concavo-convex in the magnetic recording layer (for example, refer to Japanese Patent Laid-Open No. H9-97419).

A process for providing the concavo-convex in the magnetic recording layer can be roughly classified into two types. One type is a method in which a desired mask is formed on a substrate on which a magnetic material has been deposited, and the magnetic material of an unmasked portion is directly etched. Another type is a method in which a desired mask is formed on a substrate per se, or a nonmagnetic film such as silicon nitride or silicon oxide (hereinafter called “substrate” including both of the substrate and the nonmagnetic film) which has been deposited on the substrate, and after the substrate is subjected to a concavo-convex processing due to etching, the magnetic material is deposited on the substrate.

As a method of masking the substrate or the magnetic material, there are a nano-imprint method, an optical lithography, and an electron beam lithography. Also, as the method of etching the substrate or magnetic material which has been masked, there are proposed wet etching and dry etching such as plasma etching, ion beam etching, ion milling, or a neutral beam etching. In particular, the plasma etching technique that has been widely used in the manufacture of a semiconductor device can be expected in the application of the concavo-convex processing of the substrate or the magnetic material.

In the plasma etching, a processing gas is introduced into a pressure-reduced processing chamber, and a high frequency electric power is supplied to the processing chamber from a source power supply through a plate antenna or a coil antenna to bring the gas into plasma. The resultantly produced ions or radicals are irradiated onto the substrate to advance the plasma etching. The plasma sources are of various systems such as a magnetic field microwave type, an inductively coupled plasma (ICP) type, or a capacitively coupled plasma (CCP) type according to a difference in the system that produces the plasma.

Further, a high frequency bias is applied to a stage on which the substrate is mounted, thereby making it possible to positively attract ions in the plasma onto the substrate. As a result, it is possible to realize an improvement in the etching rate or an improvement in the vertical processability. The high frequency bias to be frequently used is a frequency lower than the frequency of the source power supply which is used in the generation of plasma by one digit to three digits.

Also, Japanese Patent Laid-Open No. 2006-222127 discloses an example of a substrate holder suitable for dry-etching the substrate one by one.

SUMMARY OF THE INVENTION

However, when an attempt is made to conduct a concavo-convex processing on the magnetic recording media by the aid of the conventional plasma etching device, there arise the following two problems. First, as a first problem, in the case where the substrate material is a nonconductive material such as hardened glass, it is difficult to apply the high frequency bias to the substrate. In the case where the substrate is the nonconductive material, the high frequency impedance between the stage and the plasma becomes remarkably high in only a portion of the stage on which the substrate is mounted. For that reason, it is difficult to allow the high frequency current to flow through the substrate, and the etching of the substrate is not advanced. When the high frequency bias power is increased in order to compensate this drawback, not only the energy efficiency is deteriorated but also another portion of the stage on which the substrate is not mounted is etched. As a result, there occur a risk that the lifetime of the stage part is shortened to increase the running costs, and a risk that particles are caused by scraping off the stage part.

Subsequently, as a second problem, the pattern on the substrate back side is damaged, or the particles are stuck onto the substrate back side. In order to enhance the recording capacity per one media, the magnetic recording media has both of front and back sides used as the recording layers. Accordingly, a discrete track media and the patterned media are also required to subject both of front and back sides to the concave-convex processing. When the back side of the substrate comes in contact with the surface of the stage while the front side of the substrate, that is, a surface of the substrate which is in contact with the plasma is processed, the concave-convex pattern on the rear side of the substrate is damaged, or the particles are stuck onto the concave-convex pattern on the back side of the substrate. As a result, there is the high possibility that a serious defect is induced in the concave-convex pattern.

In order to prevent the above drawback, the following method is also considered for holding the substrate in the plasma in such a manner that the substrate is not mounted directly on the stage and both sides of the substrate are in contact with each other, and etching both of the front and back sides of the substrate on the block. However, the above method of processing both sides of the substrate on the block suffers from such a problem that it is difficult to apply a bias to the substrate that is a nonconductive material with the results that the etching rate is not increased, or the vertical processing becomes difficult.

Further, in order to subject both sides of the substrate to an excellent concavo-convex pattern processing, attention must be paid to not only the etching process but also the transportation of the substrate. In the normal etching device for the semiconductor device fabrication, a transportation arm always comes in contact with the rear side of the silicon substrate when the silicon substrate is carried in or carried out of the processing chamber, the transportation arm always comes in contact with the back side of the silicon substrate. Accordingly, it is impossible to use the same transportation system when the magnetic recording media that requires the double-side processing is etched.

Japanese Patent Laid-Open No. H9-97419 and Japanese Patent Laid-Open No. 2006-222127 do not take the above problems into consideration.

The present invention has been made to solve the above problems, and therefore one object of the present invention is to provide a substrate holder that prevents a pattern that is formed on a substrate to be processed from being damaged at the time of processing or transporting the substrate to be processed with both sides to be processed, and is suitable for efficiently forming the pattern on both of the front and back sides of the substrate to be processed.

Another object of the present invention is to provide a substrate fabricating device and a method of manufacturing a magnetic recording media, which are low in the costs and suitable for efficiently forming a magnetic recording media in which a recording layer is formed in a concave-convex pattern on both surfaces of the substrate.

The substrate holder according to the present invention includes a plate-like insulator member having plural through-holes, and a conductive holding member with convexes that can be engaged with the respective throughholes. In a state where the convexes are engaged with the through-holes, a substrate mounted surface and a gap having a thickness in a direction perpendicular to the substrate mounted surface are formed in each of the through-holes.

In this example, the thickness of the gap is set to 0.05 mm to 1 mm, the thickness of the insulator member is set to 1 mm to 15 mm, and the impedance of the insulator member viewed from the high frequency bias is set to be larger than a combined impedance of the gap and the substrate to be processed. Also, the substrate holder is so configured as to mount plural substrates to be etched thereon.

Also, in a method of fabricating a magnetic recording media having recording layer on each of front and back sides thereof according to the present invention, at least three steps of etching a base resist on both sides of a substrate to be processed by the aid of plasma of a gas system containing O₂or CO₂, etching an insulator layer by the aid of plasma of a fluorocarbon system, and removing the resist that remains on an upper portion of the insulator layer by the aid of the plasma of O₂system, are conducted in the same processing chamber, consistently.

Further, in a plasma processing method according to the present invention, a substrate holder per se on which a substrate having both sides to be processed is mounted is carried in a processing chamber of the etching device, and the substrate is etched together with the substrate holder. In this example, it is desirable that the outer diameter of the substrate holder is set to the same size as that of a wafer size for a semiconductor device, for example, 200 mm or 300 mm.

In the substrate holder according to the present invention, because a gap is defined in a rear side of the substrate to be processed, the pattern formed on the rear side of the substrate can be prevented from being damaged while the substrate front side is etched. Also, because the substrate is transported together with the substrate holder, the pattern formed on the rear side of the substrate can be prevented from being damaged during transportation.

Also, in the substrate holder according to the present invention, the impedance of the insulator member viewed from the high frequency bias is so set to be larger than the combined impedance of the gap and the substrate to be processed. For that reason, it is possible to apply the high frequency bias to only the magnetic recording media that conducts etching, and it is possible to suppress a portion of the insulator member which is exposed directly to the plasma from being consumed. As a result, it is possible to suppress the occurrence of particles that are caused by scraping off the insulator member, and an increase in the running costs.

Also, because the substrate holder according to the present invention is so configured as to mount plural substrates to be processed thereon, a remarkable improvement in the through-put can be expected as compared with a case in which the substrate to be processed is processed one by one. In addition, the outer diameter of the substrate holder is set to 200 mm or 300 mm, thereby making it possible to conduct the a process that diverts an etching device that is widely used to manufacture the semiconductor device. As a result, it is possible to suppress the investment costs for the etching device.

Further, according to the method of fabricating the magnetic recording media of the present invention, it is possible to form the concavo-convex patterns on the recording layers on both of front and back sides of the magnetic recording media efficiently and at the low costs.

These and other objects and many of the attendant advantages of the invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, objects and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings wherein:

FIG. 1 is a perspective view showing the outline of a substrate holder according to a first embodiment of the present invention;

FIG. 2 is a cross-sectional view showing an O-A section in FIG. 1;

FIG. 3 is a diagram showing a method of mounting, reversing, and un mounting a substrate to be processed;

FIG. 4 is a plan view showing the outline of an etching device for a semiconductor;

FIG. 5 is a cross-sectional view showing the outline of an etching chamber of the etching device for the semiconductor;

FIG. 6 is a schematic view showing a state wherein etching is conducted by the aid of a substrate holder of the present invention;

FIG. 7 is a diagram showing an electrically equivalent circuit of FIG. 6;

FIG. 8 is a diagram showing the critical thickness of a plate-like insulator member to the thickness of a gap;

FIGS. 9A to 9E are conceptual diagrams showing an etching process consisting of plural steps by the aid of the substrate holder of the present invention;

FIGS. 10A to 10D are diagrams showing an etching process consisting of plural steps by the aid of the substrate holder of the present invention according to another embodiment; and

FIG. 11 is a diagram showing a substrate holder according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a description will be given of a device for etching a substrate to be processed and a method of processing the substrate according to a best mode of the present invention with reference to the accompanying drawings.

First Embodiment

A first embodiment of the present invention will be described with reference to FIGS. 1 to 8.

FIG. 1 is a perspective view showing the outline of a substrate holder according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view showing an O-A section in FIG. 1.

A substrate holder 101 includes a plate-like insulator member 1, center insulator members 2, ring-shaped conductor members 4, and a disc conductor member 5. Plural through-holes 3 are defined in the disc form plate-like insulator member 1 at regular the equal distance from a center of the insulator member 1 at regular intervals. Also, a step 31 that forms a substrate mounting surface is defined on an upper portion of each of the through-holes 3. The center insulator members 2, the ring-shaped conductor members 4, and the disc conductor member 5 are integrated together to constitute a conductive holding member. In the conductive holding member, the center insulator member 2 is located at a position corresponding to each central portion of the through-holes 3, and the ring-shaped conductor member 4 has a central portion fitted into the center insulator member 2, and has an outer peripheral portion engaged with the through-hole 3. That is, each of the center insulator members 2 and each of the ring-shaped conductor members 4 constitute a convex portion that can be engaged with the through-hole 3. A substantially ring-shaped concave portion for holding the etching substrate 12 is formed on the upper surface of the substrate holder 101 in a state where the convex portion is engaged with the through-hole 3.

FIG. 1 shows a state in which plural substantially ring-shaped substrates 12 to be etched are supported by the substrate holder 1. That is, the outer diameter of each upper end of the through-holes is slightly larger than the outer diameter of the substrate 12 to be etched so that the substantially ring-shaped substrate 12 to be etched is just received in the concave portion formed in each the through-hole 3 of the plate-like insulator member 1. The substrate 12 to be etched is held on the substrate mounting surface of the peripheral portion of the concave portion. Also, each of the substrates to be etched has the central portion held by the center insulator member 2 within the substantially ring-shaped concave portion.

As shown in FIG. 2, a gap 6 having a thickness in a direction perpendicular to the substrate mounting surface is formed between a lower side of each of the substrates to be etched, that is, the substrate mounting surface (31), and the upper side of the convex portion, that is, the upper side 40 of the ring-shaped conductive member 4 in a state where the plate-like insulator member 1 is held on the conductive holding member, and the convex portion is engaged with the through-hole 3.

FIG. 1 shows a state in which six substrates to be processed are mounted on the substrate holder 101. However, in fact, it is preferable that a larger number of substrates to be processed are mounted on the substrate holder from the viewpoint of the throughput. For example, in the case where the outer diameter of the substrate holder is set to 300 mm, and the substrates to be processed whose outer diameter is Φ2.5 inches are mounted on the substrate holder, about 12 to 14 substrates to be processed can be mounted on the substrate holder. It is needless to say that a still larger number of substrates to be processed can be mounted on the substrate holder when the outer diameter of the substrates to be processed is Φ2 inches or Φ1.8 inches. In this case, the positions of the through-holes 3 that are defined in the plate-like insulator member 1 are not limited to an example in which the through-holes 3 are arranged at regular intervals on a single circle. It is needless to say that the throughholes 3 can be located at diverse positions according to the size of the substrate or the processing conditions in such a manner that the through-holes 3 are alternately arrange on two inner and outer concentric circles.

In this example, it is desirable that the plate-like insulator member 1 and the center insulator member 2 are made of a material that is difficult to change in the quality even if the material is exposed to the plasma. That is, a material such as quartz (SiO₂), alumina (Al₂O₃), aluminum nitride (AlN), or Pyrex (registered trademark). In particular, quartz that is small in the relative permittivity is preferable because a high frequency bias is prevented from being applied to the plate-like insulator material 1 or the center insulator member 2.

Also, the plate-like insulator member 1 is provided with a positioning mark 7 for positioning when the substrates 12 to be processed are mounted on the substrate holder 101, or when the substrate holder and the substrates to be processed are carried in the etching device. The positioning mark 7 is prepared by physically providing a concave portion in the plate-like insulator member 1, or embedding a magnetic material in the plate-like insulator member 1. Means for detecting light, eddy current, or a magnetic field detects the position of the positioning mark 7 of the substrate holder 101, thereby making it possible to detect the orientation of the substrate holder 101.

In addition, it is possible to process the substrate by the aid of the existing semiconductor etching device.

That is, the outer diameter of the plate-like insulator member 1 is set to Φ200 mm or Φ300 mm, as a result of which, for example, the plate-like insulator member 1 of Φ300 mm is mounted on a lower electrode (stage) of the existing semiconductor etching device instead of a wafer of Φ300, thereby making it possible to process plural substrates to be processed at the same time.

It is preferable that the conductive holding member, that is, the ring-shaped conductive member 4 and the disc-shaped conductive member 5 are made of a conductive material such as aluminum, diverse aluminum alloys, titanium alloys, stainless steel, or boron doped silicon. Further, it is preferable that the ring-shaped conductive member 4 and the disc-shaped conductive member 5 are integrated with each other by means of brazing or welding.

As shown in FIG. 3, the substrate holder 101 is of a structure in which the conductive holding member, that is, the center insulator member 2, the ring-shaped conductive member 4, and the disc-shaped conductive member 5 can be separated vertically with respect to the plate-like insulator member 1. Also, the center insulator member 2 and the through-hole 3 have the central portions projected in the axial direction to form upper and lower steps, respectively. An upper step 21 of the center insulator member and the upper step 31 of the through-hole 3 are substantially identical with each other in the height, thereby constituting the substrate mounting surface on the concave portion by means of the step 21 and the step 31 in a state where the plate-like insulator member 1 and the center insulator member 2, and the ring-shaped conductor member 4 and the disc-shaped conductive member 5 are coupled with each other. Those steps 21 and 31 constitute the substrate mounting surface on the concave portion. Alternatively, the step 31 is made slightly higher than the step 21, and the substrate mounting surface is constituted by only the step 31. The lower step of the center insulator member 2 corresponds to the step of the center hole of the ring-shaped conductor member 4. The lower step 32 of the through-hole 3 is engaged with the outer peripheral step 41 of the ring-shaped conductor member 4. Further, the disc-shaped conductive member 5 is engaged with the recess portion formed on the lower surface of the plate-shaped insulator member 1.

As shown in FIG. 2, the gap 6 is defined between the mounting surface (31) of the substrate 12 to be processed and the upper side 40 of the ring-shaped conductive member 4. In other words, the gap 6 having the thickness of about 0.05 mm to 1 mm in a direction perpendicular to the substrate mounting surface is formed between the substrate 12 to be processed and the upper surface 40 of the ring-shaped conductor member 4 in a state where the substrate 12 to be processed is mounted on the substrate holder 101. In the substrate holder according to the present invention, the provision of the gap 6 makes it possible to conduct the etching process without damaging the pattern that has been formed on the back side of the substrate to be processed.

Subsequently, a transportation mechanism of the substrate to be processed corresponding to the substrate holder according to the present invention will be described with reference to FIG. 3. The transportation mechanism includes a lifting mechanism 8, a first substrate holding mechanism 9, and a second substrate holding mechanism 15. The first substrate holding mechanism 9 can be transported while holding the inner peripheral portion of the substrate 12 to be processed. The second substrate holding mechanism 15 is used to reverse the substrate 12 to be processed vertically while holding the outer peripheral portion of the substrate 12 to be processed.

In the case where the substrate to be processed is mounted on the substrate holder 101, the plate-like insulator member 1 is first lifted up by the lifting mechanism 8, to thereby separate the center insulator member 2, the ring-shaped conductor member 4, and the disc-shaped conductor member 5 from the plate-like insulator member 1. In this situation, the substrates 12 to be processed which have been held by the first substrate holding mechanism 9 are sequentially mounted on the mounting surfaces of the through-holes 3 of the plate-like insulator member 1, that is, the concave portions. After the substrates to be processed have been mounted on all of the plural through-holes 3 which have been defined in the plate-like insulator member 1, the lifting mechanism 8 is moved down.

Subsequently, a description will be given of the etching device that processes the substrates by the aid of the substrate holder and the transporting mechanism according to an embodiment of the present invention. FIG. 4 is a plan view showing the outline of the semiconductor etching device. The semiconductor etching device described below is one example, and can take any configurations. Also, in the following description, “the substrate holder in a state where plural substrates to be processed are located” is called “substrate holder”.

Referring to FIG. 4, reference numeral 102 denotes a hoop that receives plural substrate holders 101 each of which mounts the plural substrates 12 to be processed thereon, and is located in an atmosphere transportation portion of the etching device for the semiconductor processing.

After each of the substrate holders 101 that have been received in the hoop 102 has taken out from the hoop by means of the transportation arm 104 of the atmosphere transportation robot, the substrate holder 101 is located on an aligner 105 of the atmosphere transportation portion. The aligner 105 finely adjusts the position of the substrate holder 101 on a horizontal plane, and positions the peripheral direction of the substrate holder.

Subsequently, a description will be given of a structural example of a processing chamber 109 of the etching device which is preferable in processing the substrate to be processed by the aid of the substrate holder according to the present invention with reference to FIG. 5. FIG. 5 is a longitudinal cross-sectional view showing the outline of a semiconductor etching device.

An insulator top plate 202 and a shower plate 203 are disposed on an upper portion of a vacuum chamber 201 that is evacuated and grounded. A process gas that is supplied from a gas supply system 204 is uniformly introduced into the processing chamber by means of the shower plate 203. A stage 207 whose temperature is uniformly adjusted by the aid of a temperature adjusting mechanism 212 is disposed in the lower portion of the processing chamber. The substrate holder 101 is mounted on the stage 207. A waveguide 205 is disposed in the upper portion of the processing chamber. A microwave is supplied to the processing chamber from a plasma source power supply not shown through the waveguide. Two or three systems of solenoid coils 208 and yokes 209 are disposed in the exterior of the processing chamber 201. A magnetic field having an arbitrary configuration can be generated in the processing chamber 201 by allowing an arbitrary DC current to flow in a solenoid. The mutual reaction of the magnetic field and the microwaves enables the process gas that has been introduced into the processing chamber to be brought in a plasma state. In addition, a source electric power, the magnetic field arrangement, and the processing pressure are adjusted, thereby making it possible to control the plasma density and the plasma distribution with high precision.

A high frequency power supply 21 is connected to the stage 207 through a matching unit 210 in such a manner that a high frequency bias can be supplied to the substrate to be processed which is located on the substrate holder 101. The high frequency bias allows ions in the plasma to be positively drawn in the substrate to be processed so as to realize a vertical processing configuration and a high-speed processing speed.

Alternatively, it is possible that the wafer stage has an electrostatic chuck of the dipole type, and the disc-shaped conductor member 5 of the substrate holder is held on the wafer stage by electrostatic adsorptivity at the time of processing the substrate to be processed.

According to this embodiment, because the gap is defined on the back side of the substrate to be processed within the substrate holder, the pattern that has been formed on the back side of the substrate can be prevented from being damaged while the front side of the substrate is processed. Further, because the high frequency bias can be supplied to only the magnetic recording media, it is possible to efficiently etch only the magnetic recording media.

Second Embodiment

Subsequently, a description will be given of a method of etching a substrate with the use of the substrate holder of the present invention with reference to FIGS. 3 to 5 as a second embodiment. The substrate 12 to be processed is mounted on the substrate holder 101. At this time, it is assumed that a mask pattern has been already formed on both of front and back sides of the substrate to be processed.

First, as shown in FIG. 3, the plate-like insulator member 1 is lifted up by the lifting mechanism 8 in advance, and the substrates 12 to be processed whose inner peripheral portions are held by the first substrate holding mechanism 9 are sequentially mounted on the concave portions that are the substrate mounting surfaces of the plate-like insulator member 1. After the substrates 12 to be processed have been mounted on all of the plural substrate mounting surfaces provided in the plate-like insulator member 1, the lifting mechanism 8 is moved down. In this situation, it is important that the substrates to be processed are located on the substrate holder in such a manner that the substrate holder is not brought in contact with the pattern portions of the front and back sides of the substrates to be processed.

The substrate holder on which the plural substrates to be processed have been set up is set on a wafer cassette or a hoop for the semiconductor etching device.

Subsequently, as shown in FIG. 4, the hoop that has received the plural substrate holders on each of which the substrates 12 to be processed are located is placed on an atmosphere transportation portion of the etching device for the semiconductor processing. After the substrate holders 101 that have been received in the hoop 102 have been taken out of the hoop from the atmosphere transportation arm 104, the substrate holders 101 are placed on the aligner 105. The substrate holders 101 whose positions and directions have been adjusted by the aligner are carried into a lock chamber 106. Subsequently, after an air has been exhausted from the lock chamber by a pump not shown to create vacuum therein, the substrate holders 101 are carried in the buffer chamber 107 by means of a vacuum transportation arm 108. Thereafter, the substrate holders 101 are carried in the processing chamber 109, and subjected to a given etching process. That is, the substrates 12 to be processed are transported within the etching device for each of the substrate holders 101, and then subjected to the etching process for each of the substrate holders. In this situation, as described above, the use of the substrate holder according to the present invention makes it possible to efficiently etch only the substrates 12 to be processed, and also substantially prevents the plate-like insulator member 1 from being damaged by plasma. Further, the gap 6 that is defined on the back side of the substrate 12 to be processed does not damage the pattern on the back side of the substrate 12 to be processed.

Subsequently, the substrate holders 101 on which the substrates 12 to be processed whose one side has been processed are mounted are carried out of the processing chamber 109 by means of the vacuum transportation arm 108, and then carried in the lock chamber 106. Then, the lock chamber is purged by nitrogen gas or dry air. After a pressure within the lock chamber has been boosted up to the atmospheric pressure, the substrate holders 101 are carried out of the lock chamber by the aid of the atmosphere transportation arm, and then recovered in the hoop 102.

In the proceeding described above, the processing of all of the substrates 12 to be processed has been completed, and the substrate holders 101 on which all of the substrates 12 to be processed are mounted have been recovered. Thereafter, the hoop is recovered from the etching device.

Subsequently, a description will be given of a proceeding of reversing the front and back sides of the substrates 12 to be processed with reference to FIG. 3 again. First, the plate-like insulator member 1 is lifted up by the lifting mechanism 8 in advance. The inner peripheral portions of the substrates 12 to be processed are held by the first substrate holding mechanism 9, and the substrates 12 to be processed are lifted up from the plate-like insulator member 1. Then, after the outer peripheral portions of the substrates 12 to be processed have been held by the second substrate holding mechanism 15, the first substrate holding mechanism 9 is released. Then, the second substrate holding mechanism 15 is rotated by 180° in a direction of θ in the figure, and the upper and lower direction of the substrates is reversed. Thereafter, the inner peripheral portions of the substrates 12 to be processed are held by the first substrate holding mechanism 9, and the second substrate holding mechanism 15 is released. Finally, the first substrate holding mechanism 9 is moved down, and the substrates 12 to be processed whose front and back sides have been reversed are placed on the plate-like insulator member 1. Those sequential successive works are implemented by the number of substrates 12 to be processed.

The substrate holders 101 to which the plural substrates 12 to be processed whose front and back sides have been reversed have been set are again set up on the hoop for the semiconductor etching device. The hoop is again placed on the etching device, and the etching process of other surfaces of the substrates which have not yet been processed is implemented. The etching process is conducted by the same proceeding as that described above, and therefore its description will be omitted.

Finally, the hoop that has received the substrate holders on each of which the substrates 12 to be processed whose both sides have been processed are placed are recovered from the etching device. Thereafter, the substrates 12 to be processed are recovered from the substrate holder 101.

First, the plate-like insulator member 1 is lifted up by the lifting mechanism 8 in advance, and the substrates 12 to be processed whose inner peripheral portions are held by the substrate holding mechanism 9 are successively recovered from the concave portions of the plate-like insulator member 1. After the substrates to be processed have been recovered from all of the plural concave portions that are defined in the plate-like insulator member 1, the lifting mechanism 8 is moved down.

In the above description, the plate-like insulator member 1 is lifted up by the lifting mechanism 8 to mount or recover the substrates to be processed. Alternatively, as a modified example of the first embodiment, the substrates to be processed can be mounted or recovered even if the center insulator members 2 are pushed up. In this case, a design is made in such a manner that opening portions are defined immediately below the center insulator members 2 of the disc-shaped conductor members 5, and the lifting mechanisms for lifting up the center insulator members 2 through the opening portions are located by the number of substrates to be processed. Similarly, in this case, the configuration is made in such a manner that the gap 6 having the thickness in a direction perpendicular to the substrate mounting surface are formed between the back side of each the etching substrates, that is, the substrate mounting surface, and the front side of the concave portion, that is, the front side of the ring-shaped conductor member 4 in a state where the convex portions configured by the center insulator members 2 and the ring-shaped conductor members 4 are engaged with the through-holes 3 of the plate-like insulator member 1. Also, each of the center insulator members 2 is so configured as to be movable vertically with respect to the ring-shaped conductor member 4 and the disc-shaped conductor member 5. In this case, the substrate holding mechanism 9 can be so configured to hold the outer peripheral portions of the substrates to be processed.

According to the present invention, the thickness of the gaps 6 and the thickness of the plate-like insulator member 1 are set as indicated below, thereby making it possible to efficiently apply the high frequency bias to the substrates 12 to be processed.

FIG. 6 shows a schematic diagram showing a state in which etching is conducted by the aid of the substrate holder 101. Plasma 20 that has been created by the aid of CCP or ICP or a magnetic field microwave plasma source exists above the substrate holder 101. A high frequency bias having a frequency of about 100 kHz to 13.56 MHz is applied to the disc-shaped conductor members 5 and the ring-shaped conductor members 4 of the substrate holder from the high frequency power supply 21. The bias is applied to produce an ion sheath 23 in the plasma and on the both front sides of the substrate holder and the substrate to be processed.

The supplied high frequency bias current can be broken down into a current that flows into the plasma 20 through a route b extending from the plate-like insulator member 1 to the sheath 23, and a route c that flows into the plasma through a route c extending from the gap 6 to the sheath 23 through the substrate 12 to be processed.

An electric equivalent circuit of the above state is shown in FIG. 7. In this example, all of the plate-like insulator member 1, the gap 6, and the substrate 12 to be processed are regarded as the capacitor component with respect to the high frequency bias. The sheath 23 is regarded as a nonlinear element having some impedance.

Referring to FIG. 7, reference Z1b denotes the high frequency impedance per unit area of the plate-like insulator member 1, and Zsb is a high frequency impedance per unit area of the sheath formed on the front side of the plate-like insulator member 1. Also, reference Z6c denotes the high frequency impedance per unit area of the gap 6, reference Z3c denotes the high frequency impedance per unit area of the substrate 12 to be processed, and reference Zsc denotes the high frequency impedance per unit area of the sheath formed on the front side of the substrate 12 to be processed. Also, reference Ib denotes the current density of the high frequency current that flows via the route b, and Ic is the current density of the high frequency current that flows via the route c.

Now, let us consider a case in which a combined impedance (Z6c+Z3c) that is produced by the gap 6 and the substrate 12 to be processed is equal to the impedance Z1b of the plate-like insulator member 1. This state is called “case 1”. In this case, a voltage Vsc that is applied to the sheath on the substrate 12 to be processed is naturally equal to a voltage Vsb that is applied to the sheath on the plate-like insulator member 1. Also, the current density Ic that flows in the route c is also equal to the current density Ib that flows in the route b. That is, the power density IcVsc that is consumed by the sheath on the substrate 12 to be processed is equal to the power density IbVsb that is consumed by the sheath on the plate-like insulator member 1.

Subsequently, let us consider a case in which the thickness of the plate-like insulator member 1 is slightly thickened from the above state, and the impedance Z1b that is produced by the plate-like insulator member 1 is increased. This state is called “case 2”. In this case, the following phenomenon occurs.

(1) When a voltage that is applied to the respective elements within the route b is considered, because a voltage V1b that is divided by ZIb is larger, a voltage Vsb that is applied to the sheath is conversely smaller.

(2) When the current density that is branched to the route b and the route c is considered, because Z1b>Z3c+Z6c is satisfied, the current density Ib of the bias current that flows in the route b is smaller.

(3) Due to the multiplier effect of the above items (1) and (2), the electric power Vsb×Ib that has been consumed by the sheath formed on the front side of the plate-like insulator member 1 is remarkably reduced.

As described above, the thickness of the plate-like insulator member 1 is slightly thickened, thereby remarkably reducing the electric power that is consumed by the sheath on the plate-like insulator member 1. As a result, the electric power that is consumed by the sheath on the substrate 12 to be processed is remarkably increased. That is, the bias power that has been turned on efficiently contributes to the etching of the substrate 12 to be processed.

Conversely, in the case where the thickness of the plate-like insulator member 1 is slightly reduced more than that in the case 1, the phenomenon that is completely contrary to that described in the case 2 occurs. That is, the electric power that is consumed by the sheath on the substrate 12 to be processed is remarkably reduced with the result that the bias power that has been turned on hardly contributes to the etching of the substrate 12 to be processed.

As is apparent from the above description, it is found that a critical state in which the bias power is efficiently injected to the substrate 12 to be processed rather than the plate-like insulator member 1 is the case 1, that is, a state in which the combined impedance (Z6c+Z3c) produced by the gap 6 and the substrate 12 to be processed is equal to the impedance Z1b of the plate-like insulator member 1. Also, the case 1 exhibits that the thickness of the plate-like insulator member 1 is increased, thereby making it possible to efficiently etch the substrate 12 to be processed. However, when the same concept is applied, the same advantage can be expected by decreasing the thickness of the gap 6, that is, decreasing Z6c.

Subsequently, the thickness t1 of a support dielectric member 1 with which the high frequency bias is efficiently applied to the substrate 12 to be processed when the gap 6 is set to a certain thickness t6 is specifically estimated.

A solid line in FIG. 8 represents the critical thickness t1c of the support dielectric member 1 with respect to the thickness t6 of the gap 6, and satisfies a relationship of Z1b=Z6c+Z3c. In this estimation, the specific inductive capacity of the support dielectric member 1 is 4 (quartz), the specific inductive capacity of the gap 6 is 1 (vacuum), the specific inductive capacity of the substrate to be processed is 6 (glass), and the thickness of the substrate to be processed is 0.65 mm. In FIG. 8, when the combination of values of t1 and t6 that exist in a region above the solid line is used, more bias is applied to the substrate to be processed rather than the support dielectric member.

Further, a broken line in FIG. 8 represents T1c, and satisfies a relationship of Z1b=1.5×(Z6c+Z3c). When the combination of the values of t1 and t6 that exist in a region above the broken line is used, it is possible that the high frequency bias is further efficiently applied to the substrate 12 to be processed. In this example, the broken line in FIG. 8 can be substantially represented by a line of T1c=0.65+6×t6 with the use of the critical thickness t1c and the thickness t6 of the gap 6. In addition, the value 0.65 of an intercept in a linear expression that expresses the broken line corresponds to the thickness 0.65 mm of the substrate to be processed. That is, in the case where it is assumed that the thickness of the substrate 12 to be processed is t3, the thickness t1c of the support dielectric member 1 can be so determined as to satisfy a relationship of t1c>(t3+6×16) with respect to the thickness 16 of the gap 6.

Also, FIG. 8 shows a chain line that represents a processing limit and a chain double-dashed line that represents a transportation limit. The processing limit is defined with a precision when the dielectric support member 1 is machined, and represents the minimum value of the thickness of the gap 6, which is about 0.05 mm. Also, the transportation limit represents the maximum thickness of the thickness t1c of the support dielectric member 1 which can be transported by the general semiconductor etching device, which is normally about 7 to 8 mm. Hence, a shaded region is a desirable region. It is desirable that the support dielectric member 1 is thicker from the viewpoint of efficiently applying the bias to the substrate to be processed. However, when the support dielectric member 1 is too thick, there is a risk that the support dielectric member 1 comes in contact with a part of the etching device on the transportation route. The risk can be eliminated by slightly altering the semiconductor etching device. However, in the case where an increase in the costs of the insulator member or the weight of the insulator member is taken into consideration, it is estimated that the thickness t1c has the limit of about 15 mm.

According to this embodiment, the substrate holder is configured in such a manner that the impedance of the insulator member viewed from the high frequency bias is made larger than the combined impedance of the gap and the substrate to be processed. For that reason, it is possible to apply the high frequency bias to only the magnetic recording media that conducts the etching. As a result, it is possible to efficiently etch only the magnetic recording media, and it is also possible to suppress a portion of the insulator member which is exposed directly to the plasma from being consumed. With the above configuration, it is possible to suppress the occurrence of particles which are attributable to the scrape of the insulator member, or an increase in the running costs.

Third Embodiment

Subsequently, FIGS. 9A to 9E show an example of a fabrication process using the substrate holder 101 according to the present invention. In this case, the substrate is a magnetic recording media such as a discrete track media. The discrete track media is a recording media that is physically and magnetically isolated by grooves where the respective data tracks are formed. The discrete track media leaves only the track portion necessary for recording, removes magnetic materials between the tracks which are unnecessary for recording, and fills the removed portions with nonmagnetic materials. In the fabricating process, a pattern is first transferred to a resist resin on the recording media, and grooves are defined in the surface of the recording media by dry etching with the transferred resin pattern as a mask material. In order to ensure the floating stability of a magnetic head, after the grooves that have been formed only are filled with the nonmagnetic material and flattened, a protective film is formed on the grooves. In order to again embed the grooves that have been formed once to mirror-finish the surface of the recording media, a microfabrication technique of nano order is demanded. Hereinafter, a description will be made with reference to the drawings.

FIG. 9A shows a state of the substrate to be processed that is carried in the etching processing chamber together with the substrate holder 101, in other words, a state in which an insulator layer 302 is formed on a hardened glass substrate 303, and a resist mask portion 301 of a desired pattern (that is, a dot pattern, a groove pattern, and a servo pattern) is formed on the insulator layer 302. In this example, the insulator layer 303 is made of silicon nitride or silicon oxide. Also, the mask portion 301 is formed by using an imprint method or a light or electron beam lithography method.

First, as a first process, a base resist portion is removed by dry etching in the etching processing chamber as shown in FIG. 9B. In the first process, it is necessary to remove the base resist layer while suppressing the side etched quantity, and also the selectivity of the underlying insulator layer 302 is required. To satisfy those requirements, O₂or CO₂is employed. Further, those gases are diluted with a gas that is low in reactivity such as N₂or Ar, thereby making it possible to expect the suppression of the side etched quantity.

Subsequently, the insulator layer 302 is etched in a second process as shown in FIG. 9C. In this step, the vertical workability of the insulator layer and the selectivity of the resist material that is a mask are required. For that reason, there are many cases in which two or three kinds of fluorocarbon gases such as CF₄, CHF₃, CH₂F₂, C₄F₈, C₅F₈, or C₄F₆are mixed together in use, or in which those fluorocarbon gases are diluted with a gas that is small in the reactivity such as Ar, N₂, or Xe, and also added with O₂. Also, when oxygen atmosphere remains in the first process, the resist selectivity may be deteriorated. For that reason, it is desirable to interrupt discharge between the first process and the second process.

Subsequently, in a third process, as shown in FIG. 9D, the resist material that remains on the upper portion of the resist is subjected to ashing by means of O₂plasma and removed. Also, in the present invention, the above first process to third process can be conducted in one etching processing chamber consistently.

The fluorocarbon gases used in the above second process is high in the sedimentary property and CF polymer is deposited on a wall within the processing chamber. As a result, there is the high possibility that the etching characteristic changes with time, or polymer is peeled off from the wall to produce particles. However, the third process not only removes the resist material that remains on the pattern, but also removes the CF polymer that has been deposited on the wall for cleaning. In other words, the first process to the third process are conducted in one etching processing chamber consistently, thereby making it possible to always hold the processing of FIGS. 9A to 9D constant. As a result, the processing that is stabilized with the low particles for a long period of time can be expected. The first process to the third process are implemented to conduct the processing of FIGS. 9A to 9D is the feature of the substrate holder and the etching method using the substrate holder according to the present invention. It is needless to say that the same advantages are obtained even in the case where another process is added to the above three processes and executed in one etching processing chamber consistently.

After the completion of etching the insulator layer 302, a wet cleaning process is conducted by a wet processing device. Thereafter, plural layers of magnetic material 304 made of an alloy of Co, Ni, Fe, or Pt are deposited by means of the sputtering device to form a state in which the magnetic material is patterned as shown in FIG. 9E. In addition, the patterned concave portions are embedded with an insulator by sputtering or SOG (spin on glass) coating, and then flattened by a CMP (chemical mechanical polishing) method, etching back, or milling, thereby making it possible to produce the magnetic recording media such as the discrete track media in which the surface is very smooth and the magnetic material has been patterned.

According to this embodiment, because a configuration is made to mount the plural substrates to be processed, a remarkable improvement in the throughput can be expected as compared with a case in which the substrates to be processed are processed one by one. Also, when the outer diameter of the substrate holder is set to 200 mm or 300 mm, it is possible to conduct the processing that diverts the etching device that is widely used to manufacture the semiconductor device. As a result, it is possible to suppress the investment costs for the etching device.

Fourth Embodiment

FIGS. 10A to 10D are diagrams showing an example of another working process using the substrate holder 101 according to the present invention. The working process of FIGS. 9A to 9E is the method of patterning the substrate in advance, and depositing the magnetic material by sputtering. A fourth embodiment described below is directed to a method of directly processing the magnetic material.

FIG. 10A shows a state in which the magnetic material 304 is deposited on the hardened glass substrate 303, and the resist mask portion 301 of a desired pattern is formed on the magnetic material 304. In this example, it is general that the magnetic material 304 is of a multilayer structure for the purpose of an improvement in the magnetic characteristic and an improvement in the stability of the magnetic film. However, a single-layer structure is shown for simplifying the drawings and the description.

First, as a first process, a base resist portion is removed by dry etching in the etching processing chamber as shown in FIG. 10B. In the first process, it is necessary to remove the base resist layer while suppressing the side etched quantity, and also the selectivity of the underlying insulator layer 302 is required. To satisfy those requirements, O₂or CO₂is employed. Further, those gases are diluted with a gas that is low in reactivity such as N₂or Ar, thereby making it possible to expect the suppression of the side etched quantity.

Subsequently, in a second process, the magnetic material 304 is directly etched as shown in FIG. 10C. In this step, the gas of CO+NH₃is frequently used. Because the magnetic material is poor in the volatile, etching is hardly advanced without application of the bias. However, it is possible to efficiently apply the bias by the aid of the substrate holder of the present invention, and the processing of the high throughput can be expected.

Subsequently, in a third process, as shown in FIG. 10D, the resist material that remains on the upper portion of the pattern is subjected to ashing by means of O₂plasma and removed. As described above, a portion that implements the processing of FIGS. 10A to 10D is the substrate holder and another etching method using the substrate holder according to the present invention. Thereafter, the patterned concave portions are embedded with the insulator, and the surface is flattened, thereby making it possible to produce the magnetic recording media.

The first process to the third process are conducted in one etching processing chamber consistently, thereby making it possible to always hold the state of the processing chamber constant. As a result, the processing that is stabilized with the low particles for a long period of time can be expected. It is needless to say that the same advantages are obtained even in the case where another process is added to the above three processes and executed in one etching processing chamber consistently.

The etching method using the substrate holder of the present invention has been described above. The etching device for the semiconductor manufacture is diverted as the etching device per se, thereby making it possible to reduce the costs. Also, as the etching device, it is possible to use the etching device using any systems such as the inductive coupling type, the parallel plate type, or the magnetic microwave type.

Also, in the etching method using the substrate holder of the present invention, there is required a device for locating the substrates in the holder, and reversing and recovering the substrates. Alternatively, it is possible that the etching device per se is equipped with the above mechanism.

Fifth Embodiment

Subsequently, another embodiment for carrying out the present invention will be described. A cross-sectional view of this embodiment is shown in FIG. 11. The parts described in the first embodiment will be omitted from the description. Also, FIG. 11 shows a state in which the substrate holder according to the present invention is located on the stage 207 within the etching device. The stage 207 includes the temperature adjusting mechanism 212 and a coolant gas introducing mechanism 213. The stage 207 is connected with the high frequency power supply 211 through the matching unit 210. Also, the electrode outer peripheral portion also includes a susceptor 214 that is made of quartz or alumina in order to prevent the bias power from being leaked except for the electrode upper portion.

In this embodiment, a gas introducing mechanism 10 for introducing gas such as helium, argon, or nitrogen is disposed into the gap between the substrate 12 to be processed and the ring-shaped conductor member 5. Also, there is provided a substrate chucking mechanism 11.

The gas introducing mechanism 10 purges the gas in the gap 6 while the front side of the substrate 12 to be processed is being etched, thereby preventing the back side of the substrate 12 to be processed from being damaged. Etching is advanced by inputting ions or radical that has been produced by plasma to the substrate. However, there is the possibility that the radical enters the gap 6 while the front side of the substrate 12 to be processed is being etched.

There is the possibility that the radial that has entered the gap 6 damages the mask pattern on the back side of the substrate 12 to be processed and the pattern that has been already etched. The gas is purged in the gap 6 by means of the gas introducing mechanism 10 during the etching process, and a pressure in the gap 6 is kept higher than the processing pressure, thereby making it possible to prevent the radical from entering the gap 6.

The processing pressure is normally about 0.2 Pa to 20 Pa, but the purge pressure in the gap 6 is set to about 0.3 kPa to 3 kPa, thereby making it possible to perfectly prevent the radial from entering the gap 6. Also, the gas is purged in the gap 6, thereby making it possible to adjust the temperature of the substrate to be processed. As a result, it is possible to implement the processing with a higher precision. Also, it is possible to prevent the substrate 12 to be processed from floating when the pressure in the gap 6 is made higher than the processing process by the aid of the substrate chucking mechanism 11.

The gas supply to the substrate holder per se is conducted by the coolant gas introducing mechanism 213 that is normally equipped in the wafer stage of the etching device. In this situation, the risk that the substrate holder floats from the wafer stage can be avoided by electrically chucking the disc-shaped conductor member 5 of the substrate holder to the stage by the aid of the wafer stage having the electrostatic chuck of the dipole system.

As has been described above, according to this embodiment, the back side of the substrate to be processed can be prevented from being damaged, and it is possible to adjust the temperature of the substrate to be processed. As a result, it is possible to conduct the processing with a higher precision.

The foregoing description of the preferred embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. The embodiments were chosen and described in order to explain the principles of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto, and their equivalents.

Substrate-Holder, Etching Method of the Substrate, and the Fabrication Method of a Magnetic Recording Media

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CPC

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Priority Claims (1)