KR20080058169A - Substrate-holder, etching method of the substrate, and the fabrication method of a magnetic recording media - Google Patents

Abstract

A substrate holder, a substrate etching method, and a fabrication method of a magnetic recording medium are provided to prevent a pattern formed on a rear surface of a substrate from being damaged while a surface of the substrate is etched. A substrate holder includes a plate-shaped insulator member(1) and a conductive holding support member. The plate-shaped insulator member has a plurality of through holes(3). The conductive holding support member has a concave portion engaged with the respective through holes. A substrate mounting surface and a gap(6) having a thickness in a direction perpendicular to the substrate mounting surface are formed in the through hole in a state that the concave portion is engaged with the through holes. The thickness of the gap is equal to or greater than 0.05 mm and less than or equal to 1 mm. The thickness of the plate-shaped insulator member is equal to or greater than 1 mm and less than or equal to 15 mm.

Description

Substrate holder and substrate etching method and manufacturing method of magnetic recording medium {SUBSTRATE-HOLDER, ETCHING METHOD OF THE SUBSTRATE, AND THE FABRICATION METHOD OF A MAGNETIC RECORDING MEDIA}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate holder and a method of etching a substrate and a method of manufacturing a magnetic recording medium, and more particularly, to a substrate holder and a method of etching a substrate, which are suitable for the production of a magnetic recording medium in which a recording layer is formed in an uneven pattern.

The hard disk device rotates a disk-shaped magnetic recording medium at high speed, and records and reproduces a digital signal by the magnetic head. Conventionally, the magnetic recording medium used what deposited the magnetic substance by sputtering etc. on the disk-shaped aluminum substrate or tempered glass substrate with a very flat surface. With the increase of the recording density, the surface recording density can be improved by making the magnetic material constituting the recording layer into the recording medium, changing the magnetic material, designing the laminated structure of the magnetic material, adopting the vertical recording method, and the like. come. However, due to problems such as noise, crosstalk, and thermal fluctuation resistance due to the medium, the limit of the recording density improvement has begun to be observed in the existing recording medium. Therefore, by forming predetermined irregularities in the magnetic recording layer, a magnetic recording medium capable of realizing further improvement in recording density, a so-called discrete track media or a recording medium such as patterned media, has been proposed. (For example, refer patent document 1).

The process of forming irregularities in the magnetic recording layer can be roughly classified into two types. One is to apply a desired mask to the deposition of a magnetic substance on a substrate, and to directly etch the magnetic substance of the non-mask portion. The other is to apply a desired mask to the substrate itself or to a nonmagnetic film (hereinafter, referred to as a substrate), such as silicon nitride or silicon oxide deposited on the substrate, and to perform irregularities processing by etching the substrate. This is a method of depositing a magnetic substance.

As a method of masking a board | substrate or a magnetic body, nanoimprint method, an optical lithography, an electron beam lithography, etc. are mentioned. As a method of etching a masked substrate or magnetic material, dry etching such as wet etching, plasma etching, ion beam etching, ion milling, and neutral beam etching is considered. In particular, the plasma etching technique widely used in the manufacture of semiconductor devices can be expected to be applied to the uneven processing of substrates or magnetic bodies in consideration of mass productivity.

Plasma etching introduces a gas for processing into a reduced pressure processing chamber, and plasmaizes the gas by inputting a high frequency power from a source power source into the processing chamber through a flat plate antenna, a coil antenna, or the like, thereby removing ions and radicals generated therefrom. It proceeds by irradiating a board | substrate. Plasma sources have a variety of methods, such as a magnetic field microwave type, an inductively coupled plasma (ICP) type, and a capacitively coupled plasma type (CCP), depending on the difference in the method of generating the plasma. Doing.

In addition, by applying a high frequency bias to the stage on which the substrate is loaded, ions in the plasma can be actively introduced into the substrate, whereby the etching rate and the vertical workability can be improved. The high frequency bias is often one to three digits lower than the frequency of the source power source used for plasma generation.

In addition, Patent Document 2 discloses an example of a substrate holder suitable for dry etching a substrate one by one.

[Patent Document 1] Japanese Patent Application Laid-open No. Hei 9-97419

[Patent Document 2] Japanese Patent Application Laid-Open No. 2006-222127

However, if the uneven processing is to be performed on the magnetic recording medium using a conventional plasma etching apparatus, the following two problems arise. First, as a 1st subject, when a material of a board | substrate was a nonelectroconductor, such as tempered glass, it becomes difficult to apply a high frequency bias to a board | substrate. In the case where the substrate is a non-conductor, the high frequency impedance from the stage to the plasma is significantly increased only in the portion where the substrate of the non-conductor is loaded. Therefore, high frequency electric current becomes difficult to flow through a board | substrate, and etching of a board | substrate does not advance. In order to compensate for this, increasing the high-frequency bias power not only deteriorates energy efficiency, but also etches portions other than the substrate on which the stage is loaded, which shortens the life of stage components and the like, and increases the operating cost. There is a fear that foreign matters due to the wear of the parts are generated.

Next, as a 2nd subject, the damage of the pattern on the back surface of a board | substrate, and adhesion of a foreign material to the back surface of a board | substrate are mentioned. The magnetic recording medium uses both front and back sides as a recording layer in order to increase the recording capacity per one medium. Therefore, the discrete track media and the patterned media also need to be roughened on both sides of the front and back. If the back side of the substrate is in contact with the stage surface while the surface side of the substrate, i.e., the surface in contact with the plasma, is in contact with the stage surface, the uneven pattern on the back side of the substrate is damaged or foreign matter adheres to the uneven pattern on the back side of the substrate. It happens. This increases the possibility of causing a serious defect in the uneven pattern.

In order to avoid this, a method of holding the substrate in the plasma and etching both the front and back sides of the substrate in a batch without considering directly loading the substrate on the stage, so as to contact both sides of the substrate. By the way, in such a double-sided batch processing method, it becomes difficult to apply a bias to the board | substrate which is a nonelectroconductor, and it becomes a problem that an etching rate does not go up and a vertical process becomes difficult.

In addition, in order to perform favorable uneven | corrugated pattern process on both surfaces of a board | substrate, attention should be paid not only not only during an etching process but also about conveyance of a board | substrate. In the normal etching apparatus for semiconductor device manufacture, when carrying a silicon substrate in and out of a process chamber, a conveyance arm necessarily contacts the back surface of a silicon substrate. Therefore, it is impossible to use the same conveyance system when etching a magnetic recording medium for which duplex processing is essential.

In the said patent document 1 and patent document 2, these subjects are not considered at all.

One of the objectives of the present invention is to avoid damage to a pattern formed on a substrate during processing or transport of the substrate having the surface to be treated on both sides, and to efficiently form the pattern on both sides of the substrate. It is to provide a suitable substrate holder.

Another object of the present invention is to provide a low cost substrate manufacturing apparatus and a method of manufacturing a magnetic recording medium, which are suitable for efficiently forming a magnetic recording medium having a recording layer formed on both surfaces of a substrate in an uneven pattern.

The board | substrate holder of this invention is equipped with the plate-shaped insulator member provided with the some through hole, and the electroconductive holding member provided with the convex part which can couple to each said through hole, and the said convex part couple | bonded with the said through hole in the state And a gap portion having a thickness in the direction perpendicular to the substrate loading surface and the substrate loading surface is formed in the through hole.

Here, the thickness of the gap portion is set between 0.05 mm and 1 mm, the insulator member is set to a thickness of 1 mm to 15 mm, the impedance of the insulator member viewed from a high frequency bias, the gap portion and the substrate to be processed. It is characterized by making it larger than the combined impedance of and. The substrate holder is configured to allow a plurality of substrates to be etched.

Further, the manufacturing method of the magnetic recording medium having a double-sided recording layer on the both according to the invention, the step of etching the base resist by plasma of the gas system containing O ₂ or CO ₂ for a substrate to be processed on both sides, Consistent processing of at least three steps of the step of etching the insulator layer by the fluorocarbon plasma and the step of removing the resist remaining on the insulator layer by the O ₂ plasma are performed in the same process chamber. It features.

Moreover, the plasma processing method which concerns on this invention is characterized by carrying in the plasma processing for every board | substrate holder, carrying the board | substrate holder itself which mounted the to-be-processed substrate which has a to-be-processed surface on both surfaces, into a process chamber of an etching apparatus. Here, the outer diameter of the substrate holder is preferably 200 mm or 300 mm which is the same as the wafer size for the semiconductor device.

In the substrate holder according to the present invention, since the gap portion is formed on the back surface of the substrate to be processed, it is possible to avoid damaging the pattern formed on the back surface of the substrate while etching the substrate surface. Moreover, since conveyance is performed for every board | substrate holder, damaging the pattern formed in the back surface of a board | substrate during conveyance can also be avoided.

Further, the substrate holder according to the present invention is configured so that the impedance of the insulator member seen from the high frequency bias is larger than the combined impedance between the gap portion and the substrate to be processed, so that the high frequency bias is applied only to the magnetic recording medium to be etched. can do. As a result, only the magnetic recording medium can be etched efficiently, and the portion directly exposed to the plasma by the insulator member can be suppressed from being consumed. Thereby, generation | occurrence | production of the foreign material resulting from abrasion of the said insulator member, and an increase of operation cost can be suppressed.

Moreover, since the board | substrate holder which concerns on this invention is comprised so that a several to-be-processed board | substrate can be loaded, the improvement of the throughput can be expected significantly compared with the case where a to-be-processed board | substrate is processed one by one. In addition, by setting the outer diameter of the substrate holder to 200 mm or 300 mm, useful processing of the etching apparatus widely used for manufacturing a semiconductor device becomes possible, and the investment cost for the etching apparatus can be suppressed.

Further, according to the method for manufacturing a magnetic recording medium according to the present invention, an uneven pattern can be formed efficiently and at low cost on the recording layers on both sides of the magnetic recording medium.

EMBODIMENT OF THE INVENTION Hereinafter, the best form for implementing the etching process apparatus and processing method of the to-be-processed substrate of this invention is demonstrated using drawing.

<First Embodiment>

A first embodiment of the present invention will be described with reference to Figs.

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

The substrate holder 101 is composed of a plate-shaped insulator member 1, a center insulator member 2, a ring-shaped conductor member 4, and a disc-shaped conductor member 5. The disk-shaped insulator member 1 of a disc shape is provided with the some through-hole 3 at equal intervals in the position which is equidistant from the center. In addition, each through hole is provided with a stepped portion serving as a substrate loading surface thereon. The center insulator member 2, the ring-shaped conductor member 4, and the disc-shaped conductor member 5 are integrated to form a conductive holding member. In this electroconductive holding member, the center insulator member 2 is located in the position corresponding to the center part of each through hole 3, and the ring-shaped conductor member 4 fits the center insulator member 2 in the center part. The outer peripheral portion is configured to engage the through hole 3. That is, the center insulator member 2 and the ring-shaped conductor member 4 constitute a convex portion that can be coupled to the through hole 3, and in the state where the convex portion is coupled to the through hole 3, the substrate hole. On the upper surface of the dummy 101, a substantially ring-shaped recess is formed to hold the substrate 12 to be etched.

FIG. 1 shows a state in which a plurality of substantially ring-shaped etching target substrates 12 are supported by the substrate holder 101. That is, the outer diameter of the upper end of each through hole 3 is slightly larger than the outer diameter of the to-be-etched substrate 12, and the substantially ring-shaped to-be-etched substrate 12 is each through-hole 3 of the plate-shaped insulator member 1. ), The etching target substrate 12 is held on the substrate mounting surface of the periphery of the recess. In addition, each etching target board | substrate is hold | maintained in the vicinity of the center part by the center insulator member 2 in the substantially ring-shaped recessed part. As shown in Fig. 2, in the state where the plate-shaped insulator member 1 is held on the conductive holding member and the convex portion is engaged in the through hole 3, the lower surface of each etching target substrate, in other words, the substrate loading surface Between the surface of the convex portion and, in other words, the upper surface of the ring-shaped conductor member 4, a gap portion 6 having a thickness in a direction perpendicular to the substrate mounting surface is formed.

Although Fig. 1 shows a state in which six substrates to be processed are stacked in a substrate holder, it is actually preferable to configure a larger number of substrates to be loaded in view of throughput. For example, when the outer diameter of a board | substrate holder is 300 mm and the to-be-processed board | substrate of outer diameter (phi) 2.5 inch is loaded on it, it becomes possible to load about 12 or about 14 to-be-processed board | substrate. It goes without saying that the substrate to be processed having an outer diameter of 2 inches or an outer diameter of 1.8 inches can be loaded with a larger number of substrates. In this case, the position of the through hole 3 provided in the plate-shaped insulator member 1 is not limited to the example arrange | positioned at equal intervals on a single circle, The through hole 3 is carried out on two concentric circles inside and outside. Of course, various positions can be taken according to the size of a board | substrate or processing conditions, such as alternately arrange | positioning.

Here, it is preferable that the material of the plate-shaped insulator member 1 and the center insulator member 2 is hard to deteriorate even when exposed to plasma. That is, a quartz (SiO _2), a material such as alumina (Al ₂ O _3), aluminum nitride (AlN), Pyrex (registered trademark) is preferable. Among them, quartz having a low relative dielectric constant is suitable in the sense of preventing high frequency bias from being applied to the plate-shaped insulator member 1 and the center insulator member 2.

In addition, the plate-shaped insulator member 1 includes a positioning mark for positioning when the substrate 12 to be processed is loaded onto the substrate holder 101 or when the substrate holder and the substrate to be loaded into the etching apparatus ( 7) is formed. The positioning mark 7 is created by physically forming a recess in the plate-shaped insulator member 1 or by embedding a metal, a magnetic body, or the like into the plate-shaped insulator member 1. By detecting the position of the positioning mark 7 of the substrate holder 101 by detecting means other than light, eddy current, and magnetic field, it is possible to detect the orientation of the substrate holder 101.

Moreover, it becomes possible to process a board | substrate using the existing semiconductor etching apparatus. That is, by making the outer diameter of the plate-shaped insulator member 1 into φ200 mm or φ300 mm, on the lower electrode (stage) of the conventional semiconductor etching apparatus, for example, a φ300 mm plate-shaped insulator member instead of a wafer of φ300 mm. By loading (1), it becomes possible to simultaneously process a plurality of substrates to be processed.

As materials for the conductive holding member, that is, the ring-shaped conductor member 4 and the disk-shaped conductor member 5, conductive materials such as aluminum, various aluminum alloys, titanium alloys, stainless steels, boron-doped silicon, and the like are preferable. In addition, it is preferable that the ring-shaped conductor member 4 and the disc-shaped conductor member 5 are integrated by means such as soldering or welding.

As shown in Fig. 3, the substrate holder 101 has a conductive holding member, that is, a central insulator member 2, a ring-shaped conductor member 4, and a disc-shaped conductive pair member with respect to the plate-shaped insulator member 1. It is a structure which can separate (5) up and down. In addition, the center insulator member 2 and the through hole 3 are provided with a stepped portion at the top and bottom, respectively, as the center portion protrudes in the axial direction. The stepped portion 21 on the upper side of the center insulator member and the stepped portion 31 on the upper side of the through hole 3 have a plate-shaped insulator member 1, a center insulator member 2, and a ring-shaped conductor member 4. And in the state of Fig. 2 in which the disc-shaped conductive pair members 5 are bonded, the step mounting portion 21 and the step portion 31 form a substrate loading surface in the recessed portion. In addition, you may make the step part 31 slightly high and comprise a board | substrate loading surface only by this. The lower end of the center insulator member 2 corresponds to the stepped portion of the hole in the center of the ring-shaped conductor member 4. The stepped portion 41 of the outer circumference of the ring-shaped conductor member 4 engages with the stepped portion below the through hole 3. Moreover, the disk-shaped conductor member 5 couple | bonds with the recessed part formed in the lower surface of the plate-shaped insulator member 1.

A gap portion 6 is formed between the mounting surface of the substrate 12 to be processed and the upper surface 40 of the ring-shaped conductor member 4 as shown in FIG. In other words, in the state which mounted the to-be-processed board | substrate 12 to the board | substrate holder 101, the board | substrate is stacked between the to-be-processed board | substrate 12 and the upper surface 40 of the ring-shaped conductor member 4. The gap portion 6 having a thickness of about 0.05 mm to 1 mm is formed in the direction perpendicular to the plane. In the substrate holder according to the present invention, by forming the gap portion 6, the etching process can be performed without damaging the pattern formed on the back surface of the substrate to be processed.

Next, the conveyance mechanism of the to-be-processed board | substrate corresponding to the board | substrate holder which concerns on this invention is demonstrated with FIG. This conveyance mechanism is equipped with the pushing-up mechanism 8, the 1st board | substrate holding mechanism 9, and the 2nd board | substrate holding mechanism 15. As shown in FIG. The 1st board | substrate holding mechanism 9 can be conveyed, holding the inner peripheral part of the to-be-processed substrate 12. FIG. The second substrate holding mechanism 15 is used to hold the outer circumferential portion of the substrate 12 to be reversed so as to reverse the vertical direction of the substrate.

When the substrate to be processed is placed in the substrate holder 101, first, the plate-shaped insulator member 1 is pushed up by the pushing-up mechanism 8 to thereby form the center insulator member 2 with respect to the plate-shaped insulator member 1. , Ring-shaped conductor member 4 and disc-shaped conductive pair member 5 are separated. In this state, the to-be-processed substrate 12 held by the first substrate holding mechanism 9 is sequentially stacked on a mounting surface, that is, a recess, in the through hole 3 of the plate-shaped insulator member 1. . After completion of loading the substrate to be processed into all the plurality of through holes 3 provided in the plate-shaped insulator member 1, the pushing-up mechanism 8 is lowered.

Next, the etching apparatus and conveyance mechanism which process a board | substrate using the board | substrate holder which becomes 1st Embodiment of this invention are demonstrated. 4 is a plan view showing an outline of an etching apparatus for a semiconductor. The semiconductor etching apparatus shown below is an example to the last, and what kind of form may be sufficient. In the following description, the "substrate holder in a state where a plurality of substrates to be processed is provided" is referred to as a "substrate holder".

In Fig. 4, reference numeral 102 denotes a post-receiving unit for storing a plurality of substrate holders 101 in which a plurality of substrates 12 are stacked, and is provided in the air conveying section of the etching apparatus for semiconductor processing.

The board | substrate holder 101 of the state accommodated in the hoop 102 is taken out from the hoop by the conveyance arm 104 of an atmospheric conveyance robot, and is mounted in the aligner 105 of an atmospheric conveyance part. The aligner plays a role of fine adjustment of the position in the horizontal plane of the substrate holder and positioning of the circumferential direction.

Next, with reference to FIG. 5, the structural example of the processing chamber 109 of an etching apparatus suitable for processing a to-be-processed board | substrate using the board | substrate holder of this invention is demonstrated. 5 is a longitudinal sectional view showing an outline of an etching apparatus for a semiconductor.

An insulator ceiling plate 202 and a shower plate 203 are provided above the vacuum chamber 201 that is evacuated and grounded. The process gas supplied from the gas supply system 204 is uniformly introduced into the process chamber by the shower plate. In the lower part of the process chamber, the stage 207 heated at a constant temperature by the temperature control mechanism 212 is provided, and the substrate holder 101 is mounted on the stage 207. A waveguide 205 is provided above the processing chamber, and microwaves are supplied to the processing chamber from a plasma source power source (not shown) through the waveguide. Outside of the processing chamber 201, two to three solenoid coils 208 and yokes 209 are provided, and an arbitrary direct current is applied to the solenoid coil to generate a magnetic field of arbitrary shape in the processing chamber. Can be. By the interaction between the magnetic field and the microwaves, the process gas introduced into the processing chamber can be plasmalized. In addition, the plasma density and the plasma distribution can be controlled in detail by adjusting the source power, the magnetic field arrangement, the processing pressure, and the like.

The high frequency power supply 21 is connected to the stage 207 through the matching unit 210, and it is set as the structure which can apply a high frequency bias to the to-be-processed board | substrate provided in the substrate holder 101. FIG. The high frequency bias actively introduces ions in the plasma into the substrate to be processed, thereby realizing a vertical processing shape and a high processing speed.

In addition, the wafer stage is configured with a dipole type electrostatic chuck, so that the disk-shaped conductor member 5 of the substrate holder can be held on the wafer stage by an electrostatic attraction force during processing of the substrate to be processed. You may also

According to this embodiment, since the gap portion is formed on the back surface of the substrate to be processed in the substrate holder, damage to the pattern formed on the back surface of the substrate can be avoided while the substrate surface is being processed, and the high frequency bias is only applied to the magnetic recording medium. Can be applied, so that only the magnetic recording medium can be efficiently etched.

Second Embodiment

Next, a method of etching a substrate using the substrate holder according to the present invention as a second embodiment will be described with reference to Figs. First, the substrate 12 to be processed is loaded on the substrate holder 101. At this point, it is assumed that the mask pattern is already formed on both front and back surfaces of the substrate to be processed.

First, as shown in FIG. 3, the to-be-processed board | substrate which pushed up the plate-shaped insulator member 1 by the pushing-up mechanism 8, and hold | maintained the inner peripheral part with the 1st board | substrate holding mechanism 9 ( 12 is sequentially loaded into the recessed portion that is the substrate loading surface of the plate-shaped insulator member 1. After finishing loading a to-be-processed board | substrate in all the board | substrate loading surface with which the plate-shaped insulator member 1 was equipped, the pushing-up mechanism 8 is lowered. Here, it is important to provide the substrate 12 to the substrate holder without contacting the pattern portion on the front surface and the rear surface of the substrate to be processed.

The board | substrate holder which complete | finished set of several to-be-processed board | substrate is set to the wafer cassette or hoop for semiconductor etching apparatuses.

Next, as shown in Fig. 4, a hoop containing a plurality of substrate holders provided with a plurality of substrates 12 to be processed is placed in the air conveyance section of the etching apparatus for semiconductor processing. The substrate holder 101 in the state accommodated in the hoop 102 is taken out of the hoop by the atmospheric transfer arm 104 and then mounted on the aligner 105. The substrate holder whose position and direction are adjusted by the aligner is carried into the lock chamber 106. Next, after the lock chamber is evacuated by a pump (not shown), the substrate holder 101 is carried into the buffer chamber 107 by the vacuum transfer arm 108. Thereafter, the substrate holder 101 is loaded into the processing chamber 109 and subjected to a predetermined etching process. That is, the substrate 12 to be processed is conveyed into the etching apparatus for each substrate holder 101, and etching processing is performed for each substrate holder. At this time, as described so far, by using the substrate holder according to the present invention, only the substrate 12 to be processed can be efficiently etched, and the plate-shaped insulating member 1 is hardly damaged by plasma. Do not. In addition, the gap portion 6 formed on the rear surface side of the substrate 12 does not damage the pattern on the rear surface of the substrate 12.

Next, the board | substrate holder 101 which mounted the to-be-processed board | substrate 12 which finished the process of one surface is carried out from the process chamber 109 by the vacuum conveyance arm 108, and is carried in to the lock chamber 106. FIG. . Next, the lock chamber is purged with nitrogen gas or dry air. After the pressure of the lock chamber rises to atmospheric pressure, the board | substrate holder 101 is carried out from the lock chamber by the atmospheric conveyance arm, and is collected by the hoop 102.

In the order described so far, the processing of all the substrates 12 to be finished and the substrate holder 101 on which all of the substrates 12 are loaded are recovered, and then the hoop is recovered from the etching apparatus.

Next, the procedure of inverting the front and back of the to-be-processed substrate 12 is demonstrated again using FIG. First, the plate-shaped insulator member 1 is pushed up by the pushing-up mechanism 8, and the inner peripheral portion of the substrate 12 to be processed is held by the first substrate holding mechanism 9, and the substrate to be processed ( 12 is lifted from the plate-shaped insulator member 1. Next, after holding the outer peripheral part of the to-be-processed substrate 12 by the 2nd board | substrate holding mechanism 15, the 1st board | substrate holding mechanism 9 is opened. Next, the second substrate holding mechanism 15 is rotated 180 degrees in the θ direction in the figure to reverse the vertical direction of the substrate, and then the first substrate holding mechanism 9 is used to The inner peripheral part is held, and the second substrate holding mechanism 15 is opened. Finally, the 1st board | substrate holding mechanism 9 is lowered, and the to-be-processed board | substrate 12 whose front and back surfaces are reversed is provided in the plate-shaped insulator member 1. These series of operations are performed by the number of sheets to be processed 12.

The board | substrate holder 101 which set and finished the to-be-processed substrate 12 in which the several front and back surfaces were reversed is set in the hoop for semiconductor etching apparatus again. The said hoop is provided in the etching apparatus again, and performs the etching process of the surface which has not yet performed the process. Since the processing is performed in the same order as described so far, the description is omitted.

Finally, after collecting the hoop in which the substrate holder on which the two-sided processing has been completed is placed, the hoop containing the substrate holder is collected, and then, the substrate 12 is recovered from the substrate holder 101.

First, the to-be-processed board | substrate 12 which pushed up the plate-shaped insulator member 1 by the pushing-up mechanism 8, and hold | maintained the inner peripheral part with the board | substrate holding mechanism 9 is a plate-shaped insulator member 1 ) Is collected in sequence from the recess. After completion | finish of collection | recovery of the to-be-processed board | substrate from all the several recessed parts provided in the plate-shaped insulator member 1, the pushing-up mechanism 8 is lowered.

In the above description, although the plate-shaped insulator member 1 is pushed up by the pushing-up mechanism 8, the to-be-processed board | substrate is mounted and collect | recovered, but the center insulator member 2 was made into the modification of 1st Example. Even if it pushes up, a to-be-processed board | substrate can be loaded and collect | recovered. In this case, an opening is provided directly under the center insulator member 2 of the disc-shaped conductor member 5, and the pushing mechanism 8 for pushing up the center insulator member 2 through the opening is treated. The number of boards may be provided. Even in this case, the lower surface of each etched substrate in the state where the convex portions constituted by the center insulator member 2 and the ring-shaped conductor member 4 are engaged in the through hole 3 of the plate-shaped insulator member 1. In other words, a gap portion 6 having a thickness in a direction perpendicular to the substrate loading surface is formed between the substrate loading surface, the surface of the convex portion, and in other words, the upper surface of the ring-shaped conductor member 4. . In addition, the center insulator member 2 is comprised so that up-and-down movement with respect to the ring-shaped conductor member 4 and the disk-shaped conductor member 5 is possible. In this case, the substrate holding mechanism 9 may be configured to hold the outer circumferential portion of the substrate to be processed.

According to the present invention, by setting the thickness of the gap portion 6 and the thickness of the plate-shaped insulator member 1 as described below, it becomes possible to efficiently apply a high frequency bias to the substrate 12 to be processed. .

6 shows a schematic diagram when etching is performed using the substrate holder 101 according to the present invention. Above the substrate holder 101, there is a plasma 20 generated using a CCP, an ICP or a magnetic field microwave plasma source, and the disk-shaped conductor member 5 and the ring-shaped conductor member ( 4), a high frequency bias of about 100 kHz to about 13.56 MHz is applied from the high frequency power supply 21. The ion sheath 23 is formed on the upper surface of the plasma, the substrate holder, and the substrate to be processed by applying a bias.

The applied high frequency bias current is introduced into the plasma 20 via the plate-shaped insulator member 1-sheath 23 (path b), the gap portion 6-the substrate 12 to be processed-the sheath ( 23) (path c) can be considered to be decomposed into the flow into the plasma 20.

This state is shown by the electric equivalent circuit of FIG. Here, the plate-shaped insulator member 1, the gap portion 6, and the substrate 12 to be processed can all be regarded as capacitance components with respect to the high frequency bias, and the sheath 23 is a nonlinear element having an arbitrary impedance. Can be considered.

In FIG. 7, Z1b represents a high frequency impedance per unit area of the plate-shaped insulator member 1, and Zsb represents a high frequency impedance per unit area of the sheath formed on the plate-shaped insulator member 1. In addition, Z6c represents the high frequency impedance per unit area of the gap portion 6, Z3c represents the substrate 12, and Zsc represents the sheath formed on the substrate 12. In addition, Ib represents the current density of the high frequency current flowing through the path b, and Ic represents the current density of the high frequency current flowing through the path c.

Here, the case where the composite impedance Z6c + Z3c which the gap part 6 and the to-be-processed substrate 12 make is equivalent to the impedance Z1b of the plate-shaped insulator member 1 is considered. This state is called case 1. In this case, the voltage Vsc applied to the sheath on the target substrate 12 and the voltage Vsb applied to the sheath on the plate-shaped insulator member 1 are naturally equal. In addition, the current density Ic flowing through the path c and the current density Ib flowing through the path b become equal. That is, the power density IcVsc consumed in the sheath on the substrate 12 and the power density IbVsb consumed in the sheath on the plate-shaped insulator member 1 become equal.

Next, consider the case where the thickness of the plate-shaped insulator member 1 is made slightly thick from the above state, and the impedance Z1b produced by the plate-shaped insulator member 1 is increased. This state is called case 2. In this case, the following phenomenon occurs.

(1) Considering the voltage applied to each element in the path b, the voltage V1b divided by Z1b becomes large, so that the voltage Vsb applied to the sheath becomes inversely small.

(2) Considering the current density classified into the path b and the path c, since Z1b> Z3c + Z6c, the current density Ib of the bias current flowing in the path b becomes small.

(3) By the synergistic effects of (1) and (2), the power (Vsb × Ib) consumed in the sheath formed on the plate-shaped insulator member 1 is greatly reduced.

Thus, by slightly thickening the thickness of the plate-shaped insulator member 1, the power consumed in the sheath on the plate-shaped insulator member 1 is greatly reduced, and as a result, the power consumed in the sheath on the substrate 12 to be processed is reduced. It will increase significantly. That is, the bias power input contributes to the etching of the to-be-processed substrate 12 efficiently.

On the contrary, when the thickness of the plate-shaped insulator member 1 is slightly reduced from the case 1, the phenomenon completely opposite to that described in the case 2 occurs. That is, since the power consumed in the sheath on the to-be-processed substrate 12 is drastically reduced, the injected bias power hardly contributes to the etching of the to-be-processed substrate 12.

As is clear from what has been described above, the critical state in which the bias power is more efficiently applied to the substrate 12 than the plate-shaped insulator member 1 is the case 1, that is, the gap portion 6 and the processing target. It can be seen that the composite impedance Z6c + Z3c produced by the substrate 12 is equal to the impedance Z1b of the plate-shaped insulator member 1. In addition, although the case 1 showed that the to-be-processed substrate 12 can be etched efficiently by increasing the thickness of the plate-shaped insulator member 1, if the same consideration method is used, reducing the thickness of the clearance part 6, In other words, the same effect can be expected by reducing Z6c.

Next, when the gap portion 6 is set to a predetermined thickness t6, if the thickness t1 of the supporting dielectric member 1 is thickened to a certain extent, whether the high frequency bias is effectively applied to the substrate 12 to be processed. Specifically, it was estimated.

The solid line in FIG. 8 shows the critical thickness t1c of the supporting dielectric member 1 with respect to the thickness t6 of the gap portion 6, and is a line satisfying the relationship of Z1b = Z6c + Z3c. Here, the dielectric constant of the supporting dielectric member 1 is 4 (quartz), the dielectric constant of the gap 6 is 1 (vacuum), the dielectric constant of the substrate to be processed is 6 (glass), and the substrate thickness is 0.65 mm. It is estimated as In FIG. 8, when a combination of the values of t1 and t6 existing in the region above the solid line is used, more bias is applied to the substrate to be processed than the supporting dielectric member.

In addition, the broken line of FIG. 8 shows T1c, and is a line which satisfy | fills the relationship whose Z1b = 1.5 * (Z6c + Z3c). By using a combination of t1 and t6 present in the region above the broken line in Fig. 8, it is possible to apply the high frequency bias to the substrate 12 more efficiently. Here, the broken line in FIG. 8 can be represented by a straight line of approximately T1c = 0.65 + 6 x t6 using the critical thickness t1c and the thickness t6 of the gap portion 6. In addition, the value 0.65 of the intercept in the straight-line formula which shows a broken line corresponds to 0.65 mm of thickness of a to-be-processed substrate. That is, when the thickness of the substrate 12 to be processed is t3, the supporting dielectric member 1 is formed so as to satisfy the relation t1c> (t3 + 6 x t6) with respect to the thickness t6 of the arbitrary gap portion 6. What is necessary is just to determine thickness t1c.

In addition, in FIG. 8, the one-dot broken line which shows a process limit and the advantage broken line which show a conveyance limit are shown. The processing limit is limited to the accuracy at the time of preparing the dielectric support member 1 by machining, and represents the minimum value of the thickness of the gap portion 6 and is about 0.05 mm. In addition, a conveyance limit has shown the maximum thickness of the thickness t1c of the support dielectric member 1 which can be conveyed with the general etching apparatus for semiconductors, and this is about 7-8 mm normally. Therefore, the area indicated by the diagonal line is a preferable area. The supporting dielectric member 1 is preferably thicker from the viewpoint of efficiently applying a bias to the substrate to be processed. However, if the supporting dielectric member 1 is too thick, it may come into contact with a part of the etching apparatus in the transfer path. This concern can be solved by making some modifications to the semiconductor etching apparatus. However, in consideration of the cost of the insulator member and the increase in the weight of the insulator member, t1c is considered to have a thickness of about 15 mm.

According to this embodiment, the substrate holder is configured such that the impedance of the insulator member seen from the high frequency bias is larger than the combined impedance between the gap portion and the substrate to be processed, so that the high frequency bias can be applied only to the magnetic recording medium to be etched. Can be. As a result, only the magnetic recording medium can be etched efficiently, and the portion directly exposed to the plasma by the insulator member can be suppressed from being consumed. Thereby, generation | occurrence | production of the foreign material resulting from abrasion of the said insulator member, and an increase of operation cost can be suppressed.

Third Embodiment

Next, Fig. 9 shows an example of a substrate processing process using the substrate holder 101 according to the present invention. The substrate in this case is, for example, a magnetic recording medium such as discrete track media. Discrete track media are recording media that are physically and magnetically separated by grooves in which respective data tracks are formed. The discrete track media leaves only the track portion necessary for recording, removes the magnetic material between the tracks unnecessary for recording, and fills it with nonmagnetic material. In the manufacturing process, first, a pattern is transferred to a resist resin on a recording medium, and grooves are formed on the surface of the recording medium by dry etching using the transferred resin pattern as a mask material. In order to ensure the floating stability of the magnetic head, the non-magnetic material is filled with the grooves once formed to be flattened, and then a protective film or the like is formed. In order to fill the grooves once formed and return them to finish the surface of the recording medium in the mirror, a fine processing technique of about nanometers is required. Hereinafter, it demonstrates based on drawing.

In Fig. 9, (a1) shows an insulator layer 302 formed on a state of a substrate to be loaded into the etching process chamber together with the substrate holder 101, in other words, a tempered glass substrate 303, and a desired pattern thereon. (I.e., a dot pattern, a groove pattern, a servo pattern) is shown. Here, the material of the insulator layer 303 is made of silicon nitride, silicon oxide or the like. In addition, the mask part 301 is formed using the imprint method, the light, or the electron beam lithography method.

First, as the first step, the base resist portion is removed by dry etching in the etching processing chamber as shown in (a2). In this first step, since it is necessary to remove the base resist layer while suppressing the amount of side etch, and selectivity with the underlying insulating film layer 302 is required, O ₂ or CO ₂ is used. Further, by diluting these gases with a gas having a small reactivity such as N ₂ or Ar, it is possible to further reduce the amount of side etch.

Next, in the second step, as shown in (a3), the insulator layer 302 is etched. In this step, since the vertical workability of the insulator layer and the selectivity with the resist material as a mask are required, fluorine such as CF ₄ , CHF ₃ , CH ₂ F ₂ , C ₄ F ₈ , C ₅ F ₈ , C ₄ F _6, etc. In the case of using two or three kinds of carboxyl-based gases, the fluorocarbon-based gases are often diluted with gases having low reactivity such as Ar, N ₂ , Xe, and O ₂ is often added. . In addition, if the oxygen atmosphere in the first step remains, the resist selectivity may decrease. Therefore, it is preferable to stop the discharge between the first step and the second step.

Next, in the third step, as shown in (a4), the resist material remaining on the pattern is ashed and removed by O ₂ plasma. Moreover, in this invention, the said 1st process-the 3rd process can be processed in one etching process chamber consistently.

The fluorocarbon-based gas used in the above-described second step has a strong deposition ability, and CF-based polymers are also deposited on the walls of the processing chamber. Thereby, it is highly likely that the etching characteristics will change over time or the polymer will peel off from the wall, resulting in foreign matters. However, the third process not only removes the resist material remaining on the pattern but also cleans the CF-based polymer deposited on the wall. It also plays a role. In other words, by consistently processing the first to third processes in one etching processing chamber, it is possible to constantly maintain the state of the processing chamber and expect stable treatment for a long time with low foreign matter. By performing the process from the first step to the third step, the part to perform the processing from Figs. 9A to 9A is a feature of the etching method using the substrate holder and the substrate holder according to the present invention. Moreover, of course, the same effect is also carried out also when adding another process to the said 3 process and carrying out the process coherently in one etching process chamber.

After the etching of the insulator layer 302 is finished, a plurality of layers of the magnetic body 304 made of an alloy such as Co, Ni, Fe, Pt, etc. are formed by a sputtering device after the wet cleaning process by the wet processing device. It deposits and forms the patterned state of the magnetic body as shown to Fig.9 (a5). In addition, the discrete track is filled with an insulating material by sputtering or spin on glass (SOG) coating, and planarized by CMP (Chemical Mechanical Polishing) method, etch back, milling, etc., so that the surface is very smooth and the magnetic track is patterned discrete track. Magnetic recording media such as media can be created.

According to this embodiment, since a plurality of substrates to be processed can be stacked, a significant improvement in throughput can be expected as compared with the case where the substrates to be processed are processed one by one. In addition, by setting the outer diameter of the substrate holder to 200 mm or 300 mm, useful processing of the etching apparatus widely used for manufacturing a semiconductor device becomes possible, and the investment cost for the etching apparatus can be suppressed.

Fourth Example

Next, Fig. 10 shows an example of another processing process for a substrate using the substrate holder 101 according to the present invention. In the processing process of Fig. 9, the substrate is patterned in advance, and the magnetic material is deposited thereon by sputtering. However, the fourth embodiment described below is a method of directly processing the magnetic material.

10B illustrates a state in which the magnetic body 304 is deposited on the tempered glass substrate 303 and the resist mask portion 301 having a desired pattern is formed thereon. Here, the magnetic material 304 generally takes a multilayer structure to improve magnetic properties or to improve the stability of the magnetic film. However, the magnetic material 304 is shown in a single layer structure for the sake of simplicity of the drawings and description.

First, as shown in (b2) as a 1st process, a base resist part is removed by dry etching in an etching process chamber. It is necessary to remove the base resist layer while suppressing the amount of side etch, and O ₂ or CO ₂ is used because selectivity with the underlying insulating film layer 302 is required. Further, by diluting these gases with a gas having a small reactivity such as N ₂ or Ar, it is possible to further reduce the amount of side etch.

Next, as shown in (b3) as the second step, the magnetic material 304 is directly etched. Gas systems such as CO + NH ₃ are often used for this. Since the magnetic material lacks volatility, almost no etching proceeds without applying a bias, but by using the substrate holder according to the present invention, the bias can be efficiently applied, and high throughput can be expected.

Next, as shown in (b4) as a third process, the resist material remaining on the upper part of the pattern is ashed and removed by O ₂ plasma. Thus, the part which performs the process of (b1)-(b4) is another etching method using the board | substrate holder and board | substrate holder which concerns on this invention. In addition, a magnetic recording medium can be created by filling an insulator in the pattern recess and flattening the surface.

By consistently processing the first to third processes in one etching processing chamber, the state of the processing chamber can be kept constant at all times, and stable treatment can be expected for a long time with low foreign matter. Moreover, of course, the same effect is also carried out also when adding another process to the said 3 process and carrying out the process coherently in one etching process chamber.

According to this embodiment, since a plurality of substrates to be processed can be stacked, a significant improvement in throughput can be expected as compared with the case where the substrates to be processed are processed one by one.

As mentioned above, although the etching method using the board | substrate holder which concerns on this invention was demonstrated, cost reduction can be aimed at by using what is for semiconductor manufacture regarding the etching apparatus itself. In addition, regarding an etching apparatus, you may use the etching apparatus using what kind of system other than an inductive coupling type | mold, a parallel plate type, and a magnetic field microwave waveform.

In addition, in the etching method using the substrate holder according to the present invention described above, an apparatus for installing, inverting and recovering the substrate in the holder is required when the substrate 12 to be processed is installed in the substrate holder. It is also possible to equip the etching apparatus itself.

Fifth Embodiment

Next, another embodiment for implementing the present invention will be described. 11 is a cross-sectional view of this embodiment. Description is omitted about the parts described in the first embodiment. 11 shows a state where the substrate holder according to the present invention is mounted on the stage 207 in the etching apparatus. The stage 207 is provided with the temperature control mechanism 212 and the cooling gas introduction mechanism 213, and the high frequency power supply 211 is connected through the matcher 210. The outer periphery of the electrode is also provided with a susceptor 214 made of quartz or alumina in order to prevent leakage of bias power in addition to the upper part of the electrode.

In this embodiment, the gas introduction mechanism 10 for introducing gas, such as helium, argon, nitrogen, is provided in the clearance part 6 between the to-be-processed substrate 12 and the ring-shaped conductor member 5, have. Moreover, the to-be-processed substrate chucking mechanism 11 is provided.

When the gas introduction mechanism 10 is etching the upper surface of the substrate 12 to be processed, the gas is purged in the gap portion 6 to prevent the lower surface of the substrate 12 from being damaged. Etching proceeds when ions or radicals generated by plasma enter the substrate, but there is a possibility that radicals enter the gap portion 6 while the upper surface of the substrate 12 is being etched.

The radical entering the gap 6 may damage the mask pattern on the lower surface of the substrate 12 or the pattern already etched. The gas can be purged by the gas introduction mechanism 10 in the gap portion 6 during the etching process, and the entry of radicals into the gap portion 6 can be prevented by maintaining the pressure of the gap portion 6 higher than the processing pressure. .

Although the processing pressure is usually about 0.2 Pa to 20 Pa, the entry of radicals into the gap 6 can be completely prevented by setting the purge pressure to the gap 6 about 0.3 kPa to 3 kPa. In addition, by performing gas purge on the gap portion 6, it is possible to adjust the temperature of the substrate to be processed, and thus more precise processing can be performed. In addition, the processing target substrate chucking mechanism 11 can prevent floating of the processing target substrate 12 when the pressure in the gap portion 6 is higher than the processing pressure.

The gas supply to the substrate holder itself is performed from the cooling gas introduction mechanism 213 which is usually provided in the wafer stage of the etching apparatus. At this time, the fear that the substrate holder will rise from the wafer stage can be avoided by electrically chucking the disk-shaped conductor member 5 of the substrate holder to the stage using a wafer stage equipped with a dipole electrostatic chuck. .

As described above, damage to the back surface of the substrate to be processed can be prevented by using the present embodiment, and temperature of the substrate to be processed can be prevented, so that more precise processing can be performed.

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

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

3 illustrates a method of loading, inverting and recovering a substrate 12 to be processed.

4 is a plan view showing an outline of an etching apparatus for a semiconductor.

5 is a cross-sectional view illustrating an outline of an etching processing chamber of a semiconductor etching apparatus.

6 is a schematic diagram when etching is performed using the substrate holder according to the present invention.

FIG. 7 shows an electrical equivalent circuit of FIG. 6; FIG.

8 shows the critical thickness of the plate-shaped insulator member 1 with respect to the thickness of the gap 6.

Fig. 9 is a conceptual diagram showing a etch process of a plurality of steps using the substrate holder according to the present invention.

Fig. 10 is a conceptual diagram showing a etch process of a plurality of steps in another embodiment using the substrate holder according to the present invention.

Fig. 11 shows another embodiment of the substrate holder according to the present invention.

<Explanation of symbols for the main parts of the drawings>

1: plate-shaped insulator member

2: center insulator member

4: ring-shaped conductor member

5: disk-shaped conductor member

6: gap part

7: positioning mark

8: lifting mechanism

9: first substrate holding mechanism

10: gas introduction mechanism

11: substrate to be processed chucking mechanism

12: substrate to be processed

15: second substrate holding mechanism

21, 211: high frequency power supply

101: Board Holder

102: hoop

104: Standby bounce arm

105: aligner

106: lock room

107: buffer chamber

108: vacuum conveyance arm

109: treatment chamber

201: vacuum chamber

202: Insulator Ceiling Panel

203: Shower Plate

204 process gas supply system

205 waveguide

207: stage

208: coil

209: York

210: matcher

212: temperature mechanism

213: cooling gas supply mechanism

301: mask portion

302: insulator layer

303: tempered glass substrate

304: magnetic material

Claims (11)

Provided with a plate-shaped insulator member provided with a plurality of through holes, and a convex portion capable of engaging with each of the through holes, And a gap portion having a thickness in a direction perpendicular to the substrate loading surface and a substrate loading surface is formed in the through hole in the state where the convex portion is coupled to the through hole. The substrate holder according to claim 1, wherein the gap portion has a thickness of 0.05 mm or more and 1 mm or less, and the plate-shaped insulator member has a thickness of 1 mm or more and 15 mm or less. The thickness of said gap t6 is formed between the said convex part surface and the bottom surface of the said to-be-processed substrate, when the thickness of the to-be-processed substrate held by the said board | substrate loading surface is t3, A substrate holder characterized by satisfying a relationship in which the thickness t6 of the gap portion is 0.05 mm or more and 1 mm or less, and the thickness t1c of the insulator member is 1 mm or more and 15 mm or less, and t1c> (t3 + 6 x t6). The plate-shaped insulator member and the conductive holding member are made of a disc-shaped member, In the direction perpendicular to the board | substrate loading surface, the said plate-shaped insulator member and the said electroconductive holding member are comprised so that separation is possible. The substrate holder according to claim 1, further comprising a mechanism for introducing a gas into the gap portion. It is an etching processing apparatus provided with an atmospheric transfer robot, a lock chamber, a vacuum transfer robot, and a vacuum processing chamber, and etching the to-be-processed board | substrate which has a to-be-processed surface on both surfaces, An atmospheric transfer robot for transferring the substrate holder between a hoop capable of accommodating a plurality of substrate holders in which a plurality of substrates to be processed are stacked and the lock chamber; And a vacuum transfer robot for transferring the substrate holder between the lock chamber and the vacuum processing chamber. The vacuum processing chamber has a stage for loading the substrate holder to etch one surface of the substrate to be processed, The substrate holder includes a plate-shaped insulator member having a plurality of through-holes, and a conductive holding member having a convex portion that can be coupled to each of the through-holes, and the convex portion of the conductive holding member is formed of the plate-shaped insulator member. In the state coupled to the through hole, a gap between the substrate stacking surface and a thickness in a direction perpendicular to the substrate stacking surface is formed in the through hole, and the plate-shaped insulator member and the conductive holding member are detachably separated. Composed of, After inverting the surface of the processing target substrate in the substrate holder on which one surface of the processing target substrate has been processed, the substrate holder is mounted on the stage to etch the other surface of the processing substrate. It is comprised, The etching apparatus characterized by the above-mentioned. It is a manufacturing method of the magnetic recording medium which has a recording layer in both front and back, Etching the base resist with a gas plasma containing O ₂ or CO ₂ on both surfaces of the substrate, A process of etching the insulator layer by plasma of fluorocarbon, and O ₂ A method of manufacturing a magnetic recording medium, characterized in that at least three steps of removing the resist remaining on the insulator layer by plasma are performed in the same processing chamber. 8. The method of manufacturing a magnetic recording medium according to claim 7, wherein discharging is stopped between the steps. In the etching processing apparatus provided with an atmospheric conveyance part, a lock, a vacuum transfer robot, and a vacuum processing chamber, it is an etching method which etches both surfaces of a to-be-processed substrate using a substrate holder, The substrate holder includes a plate-shaped insulator member having a plurality of through-holes, and a conductive holding member having a convex portion that can be coupled to each of the through-holes, and the convex portion of the conductive holding member is formed of the plate-shaped insulator member. In the state of being coupled to the through hole, a gap between the substrate stacking surface and the thickness in the direction perpendicular to the substrate stacking surface is formed in the through hole. An etching method characterized by performing a plurality of processing steps on the processing target substrate loaded on the substrate holder in the same vacuum processing chamber. The plasma etching method according to claim 9, For the to-be-processed substrate loaded in the substrate holder, Etching the base resist by a gaseous plasma containing O ₂ or CO ₂ , and Etching the insulator layer by a fluorocarbon plasma; At least three steps of removing the resist remaining on the insulator layer by an O ₂ plasma are consistently performed on the substrate to be treated in the same vacuum processing chamber. The plasma etching method according to claim 9, For the to-be-processed substrate loaded in the substrate holder, Etching the base resist by a gas-based plasma containing O ₂ or CO ₂ , etching a magnetic layer by a CO + NH ₃ -based plasma, and performing an O ₂ -based plasma on top of the magnetic body. At least three steps of removing the remaining resist are carried out consistently in the same vacuum processing chamber.

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