JP2938575B2 - Processing method of magnetic head slider - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the manufacture of a magnetic head for recording / reproducing information on a magnetic disk, a magnetic tape, or the like, and more particularly, to an air bearing surface of a thin film magnetic head slider which is a component of the magnetic head. The method of processing.

2. Description of the Related Art For example, a flying type magnetic head used in a magnetic disk drive includes a magnetic head element (Transducer) and a magnetic head slider (hereinafter sometimes simply referred to as “slider”). The slider is a component that floats by air pressure received from the magnetic disk and separates the magnetic head element from the magnetic disk, and has a groove (air bearing groove) on the back surface (air bearing surface) for controlling air pressure. have.

In recent years, with the increase in recording density on magnetic disks,
It is required that the flying height of the magnetic head with respect to the magnetic disk be reduced. As a technology responding to this, there is a negative pressure slider disclosed in US Pat. No. 3,811,856.

This negative pressure slider has a structure in which the air pressure generated on the air bearing surface is accurately controlled by machining a groove having a special shape calculated on the air bearing surface. For this reason, it is said that there is little change in the flying height due to a change in the peripheral speed or skew angle of the magnetic disk, and it is possible to suppress a change in spacing loss between the magnetic head and the magnetic disk.

Unlike the conventional linear groove called slider rail, the air bearing groove of the negative pressure slider is composed of a complicated shape combining curves and multiple straight lines, so it must be manufactured by machining with a grinding machine etc. Was difficult.

Then, a method of processing the air bearing groove of the negative pressure slider by a so-called sputter etching method has been proposed. In this method, an air bearing groove is cut into a slider substrate by a sputtering effect of argon plasma.

For example, JP-A-56-74862 and JP-A-60-205879 show processing methods by ion beam etching or ion milling using a metal foil or a photoresistor as a mask. Further, Japanese Patent Application Laid-Open No. 61-120326 discloses a processing method by ion beam etching using a dry film resist as a mask. The ion beam etching apparatus and the ion milling apparatus used in these processing methods etch the slider substrate by the ion bombardment of argon ions generated when argon is plasma-excited, and thus both belong to the sputter etching method. .

However, some problems have been pointed out in the processing method using the sputter etching method using the argon plasma.

The first problem is a so-called "re-adhesion phenomenon" in which particles sputtered from the slider substrate due to ion bombardment adhere to the substrate again. This re-adhesion phenomenon is introduced in many documents such as Nikkan Kogyo Shimbun “Electron / Ion Beam Handbook 2nd Edition”, p.

A typical example of the reattachment phenomenon will be described with reference to FIGS. 23A and 23B. That is, molecules and atoms sputtered from the slider substrate 1 are mainly deposited on the wall surface 26 of the mask 2 such as a resist and the wall surface 27 of the air bearing groove 29 formed by etching with the progress of the etching by the argon ions 25. Thus, a re-adhesion layer 28 is formed.

However, since the etching by the argon ions 25 proceeds almost in parallel with the redeposition layer 28, the redeposition layer 28 is hardly removed by the etching (FIG. 23A). As a result, after the etching, the mask 2
When this is removed, a part of the redeposition layer 28 remains as a "burr" 28a protruding from the air bearing surface 11 (FIG. 23B).

In recent negative pressure sliders requiring a flying height of 0.1 μm or less, due to the presence of such burrs 28a, the pressure distribution on the air bearing surface 11 is not as calculated and the flying height of the magnetic head is unstable. Will be. This fluctuates the output of the magnetic head and causes a recording / reproducing error. In addition, the burrs 28a may damage the surface of the magnetic disk, causing a fatal failure to erase the data recorded on the magnetic disk.

Therefore, conventionally, in order to remove such burrs 28a, after the etching is completed, the air bearing surface 11 of the slider substrate 1 is mirror-finished using a grinding machine or the like. However, such an increase in the number of processing steps raises the manufacturing cost, and when the jig for etching is changed to a jig for mechanical grinding, sufficient positioning accuracy cannot be obtained, which causes a decrease in yield. Was.

Also, conventionally, during the etching process, the slider substrate 1 is rotated at a predetermined inclination angle with respect to the incident direction of the argon ions 25, that is, by a so-called oblique processing, a
The occurrence of a was also suppressed. That is,
By causing the argon ions 25 to enter obliquely, the redeposition layer 28 formed on the wall surface 26 of the mask 2 and the wall surface 27 of the air bearing groove 29 is to be etched away.

However, when the slider substrate 1 is rotated to uniformly irradiate the argon ions uniformly on the wall surfaces 26 and 27 facing various directions, the edge portion in the air bearing groove 29 is Shadows are temporarily generated depending on the rotation angle. Then, as exemplified in FIG. 24, the edge portion 29a that temporarily becomes a shadow is
The processing speed is lower than that of the other bottom surface region 29b in the air bearing groove 29, resulting in a raised shape.

The negative pressure slider calculates the pressure distribution on the assumption that the edge portion 29a in the air bearing groove 29 is also properly processed, so the swelling of the edge portion 29a as described above leads to an error in the pressure distribution. . As a result, it was difficult to obtain the expected floating characteristics.

As a second problem, it has been pointed out that the processing speed by the sputter etching method, that is, the etching speed is low. In recent years, slider substrates often use a very dense composite ceramic material containing aluminum oxide (hereinafter sometimes referred to as alumina) and titanium carbide as main components. Such composite ceramic materials are
In etching by the sputtering effect of argon ions,
The processing time becomes extremely long.

Usually, when the above-described composite ceramic material is processed by an ion milling method, which is a kind of sputter etching method, an etching rate in a depth direction is about 20 to 30 nm / min. Therefore, in order to machine the air bearing groove (generally, depth 5 to 20 μm) of the negative pressure slider,
A long machining time of several hours to several tens of hours was required.

As a result, not only the productivity is remarkably reduced, but also the etching apparatus is drastically consumed due to long-time operation, and it is necessary to frequently replace electrodes, filaments, and the like.

A third problem is the roughness of the etched surface. That is, in the composite ceramic material containing aluminum oxide and titanium carbide as main components, each crystal exists in an independent state. It is known that when such a composite ceramic material is processed by a sputter etching method, aluminum oxide is preferentially etched. Therefore, only the titanium carbide crystal remains on the surface, and the processed surface becomes rough. Moreover, in many cases, the titanium carbide crystal grains are in a state of being detached, which may be detached in the process of using the magnetic head, possibly damaging the surface of the magnetic disk. Further, there is a high possibility that dust may be trapped between the irregularities on the processed surface, which may cause unstable flying characteristics of the magnetic head.

As described above, in the conventional method of processing a magnetic head slider by a sputter etching method using argon plasma, a burr protrudes from an air bearing surface and remains.
It has been pointed out that problems such as reduced productivity due to slow processing time, complicated maintenance, and roughness of the processed surface.

SUMMARY OF THE INVENTION It is an object of the present invention to solve such a problem and to enable a magnetic head slider having both stable flying characteristics and high reliability to be processed in a short time.

DISCLOSURE OF THE INVENTION According to the present invention, an air bearing groove is machined in a magnetic head slider by the following first method to achieve the above object.

That is, first, a mask having a predetermined pattern is formed on a surface to be processed of a magnetic head slider substrate mainly composed of aluminum oxide and titanium carbide. After the magnetic head slider substrate on which the mask is formed is placed on an electrode in an etching apparatus, a reactive gas and an inert gas are introduced into an excitation section of the etching apparatus to excite these gases by plasma excitation. At the same time, a high-frequency bias is applied to the electrodes. Thereby, the reactive gas ions and the inert gas ions obtained by the plasma excitation are drawn into the magnetic head slider substrate, and the reactive etching by the reactive gas ions and the sputter etching by the inert gas ions proceed simultaneously.

Examples of the reactive gas that can be used in the present invention include:
There are chlorine-based gases such as chlorine gas, carbon tetrachloride gas, boron trichloride gas, a mixed gas of chlorine and boron trichloride, and bromine-based gases such as bromine gas, hydrogen bromide gas, and boron tribromide gas.

Argon gas is used as the inert gas, and the partial pressure ratio of the argon gas to the total pressure of the gas introduced into the excitation section is set to 70% or more and 95% or less. As a result, the etching rate is sufficiently high, the roughness of the etched surface is greatly improved, and the processing conditions of the magnetic head slider that requires reliability can be sufficiently satisfied.

In order to carry out the method of the present invention, for example, a vacuum chamber having an internal portion for exciting plasma, an exhaust port communicating with an exhaust pump for sucking and exhausting air and gas in the vacuum chamber, and a magnetic head slider An electrode that also serves as a substrate holder for installing a substrate and applying a bias voltage, a gas supply port that can introduce a reactive gas and an inert gas at arbitrary partial pressures, and a plasma excitation that excites these gases into plasma An etching apparatus having a structure including means is prepared.

FIG. 1 schematically shows the peripheral structure of the excitation section 14 and the magnetic head slider substrate 1 in the reactive ion etching apparatus used for carrying out the method of the present invention.

At least one of the gases capable of generating reactive gas ions, and at least one of the inert gases that are Group 0 elements, introduced into the etching apparatus, are each supplied to the excitation unit 14 at a high frequency or a microwave. Excited by the action, the plasma 3 is generated. In FIG. 1, these gases are inductively coupled and excited by high-frequency power from a high-frequency power supply 7 having a matching unit 8, and Zp in the figure represents the impedance of the plasma.

On the other hand, a high frequency power is applied to the magnetic head slider substrate 1 from a bias power source 9 via an electrode not shown in FIG. Here, a blocking capacitor 10 is inserted between the bias power supply 9 and an electrode (not shown). Therefore, this blocking capacitor 10
Of the magnetic head slider substrate 1 due to the action of the magnetic head slider substrate 1
Is in a state where a negative DC voltage component (that is, a bias voltage) is applied.

Due to this negative DC voltage component, the reactive gas ions 4 and the inert gas ions 5 generated in the plasma 3 are drawn toward the magnetic head slider substrate 1 to perform etching.

At this time, the reactive gas ions 4 mainly generate a compound having a sublimation property or a compound which easily evaporates,
The compounds are volatilized. That is, the reactive gas ions 4 are involved in so-called reactive etching.
On the other hand, the inert gas ions 5 are involved in sputter etching by ion bombardment.

Therefore, the reactive products on the magnetic head slider substrate 1 are quickly removed by the sputter etching effect of the inert gas ions 5, thereby promoting the processing.

Further, the inert gas ion 5 removes various polymers generated by the decomposition of the reactive gas and impurities flying from the vessel wall to the etched portion, and removes the reactive gas ion 4 from the magnetic head slider substrate 1. Promotes the reaction of

By such an action, the magnetic head slider substrate 1
The etching rate (i.e., the processing rate) is increased. In addition, due to the isotropic etching effect of the reactive gas ions 4, the formation of the re-adhesion layer which causes the generation of burrs is suppressed.

In addition, reactive etching preferentially etches titanium carbide, while sputter etching preferentially etches aluminum oxide. Therefore, by balancing each etching action, the aluminum oxide constituting the magnetic head slider substrate 1 is balanced. And titanium carbide can be substantially uniformly etched to form a smooth processed surface. Here, the balance of each etching action is
It can be easily performed by adjusting the partial pressure ratio between the reactive gas and the inert gas.

The present invention also enables the air bearing groove to be formed on the magnetic head slider by the following second method.

That is, a mask having a predetermined pattern is formed on a surface to be processed of a magnetic head slider substrate mainly containing aluminum oxide and titanium carbide. Then, after the magnetic head slider substrate on which the mask is formed is placed on an electrode in the etching apparatus, a reactive gas is introduced into an excitation section of the etching apparatus to excite the reactive gas into plasma, and A high frequency bias is applied to the electrodes. Thus, the reactive gas ions obtained by the plasma excitation are drawn into the magnetic head slider substrate, and the reactive etching by the reactive gas ions proceeds.

As the reaction gas, a mixed gas of chlorine and carbon tetrachloride,
Alternatively, a mixed gas of chlorine and boron trichloride is used. The partial pressure of carbon tetrachloride or boron trichloride in the total pressure of the mixed gas introduced into the excitation section is set to 60%.

The method of the present invention (second method) will be described in more detail with reference to FIG.

One of the above reactive gases is introduced into the excitation section of the reactive ion etching apparatus, and the plasma is excited by applying radio frequency (RF) power or the like. The magnetic head slider substrate 11 made of the alumina-titanium carbide composite ceramic material is etched by a chemical reaction caused by radicals and etching ions 13 generated by the plasma excitation.

The atoms 14 to be etched, such as aluminum and titanium, contained in the magnetic head slider substrate 11 are changed into volatile substances by the reaction with the etching ions 13 and are etched at a high speed.

Here, when the reactive gas contains carbon tetrachloride or boron trichloride, the carbon tetrachloride or boron trichloride reduces alumina and further accelerates the etching rate.

When a mixed gas of chlorine and carbon tetrachloride or a mixed gas of chlorine and boron trichloride is used as a reactive gas, carbon tetrachloride or boron trichloride accounts for the total pressure of the mixed gas introduced into the excitation section. The maximum etching rate is obtained when the partial pressure is 60%.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a conceptual diagram for explaining the operation of the first method of the present invention.

FIG. 2 is a conceptual diagram for explaining the operation of the second method of the present invention.

FIG. 3 is a schematic view showing an example of an etching apparatus used in the embodiment of the present invention.

FIG. 4 is a view showing a result of measurement on an etching rate performed in Example 2 of the present invention.

FIG. 5 is a view showing a measurement result on a machined surface roughness performed in Embodiment 2 of the present invention.

FIG. 6 is a view showing a result of measurement on an etching rate performed in Embodiment 3 of the present invention.

FIG. 7 is a schematic view showing another example of the etching apparatus used in the embodiment of the present invention.

FIG. 8 is a view showing a measurement result on an etching rate performed in Embodiment 4 of the present invention.

FIG. 9 is a view showing a measurement result on a machined surface roughness performed in Embodiment 4 of the present invention.

FIG. 10 is a schematic view showing another example of the etching apparatus used in the embodiment of the present invention.

FIG. 11 is a view showing a result of measurement on an etching rate performed in Example 5 of the present invention.

FIG. 12 is a view showing a measurement result regarding a machined surface roughness performed in Embodiment 5 of the present invention.

FIG. 13 is a schematic diagram showing another example of the etching apparatus used in the embodiment of the present invention.

FIG. 14 is a view showing a result of measurement on an etching rate performed in Embodiment 6 of the present invention.

FIG. 15 is a view showing a measurement result on a machined surface roughness performed in Embodiment 6 of the present invention.

FIG. 16 is a schematic diagram showing another example of the etching apparatus used in the embodiment of the present invention.

FIG. 17 is a view showing a result of measurement on an etching rate performed in Example 7 of the present invention.

FIG. 18 is a view showing a measurement result on a machined surface roughness performed in Embodiment 7 of the present invention.

FIG. 19 is a view showing a result of measurement on an etching rate performed in Example 8 of the present invention.

FIG. 20 is a view showing a measurement result regarding a machined surface roughness performed in Embodiment 8 of the present invention.

FIG. 21 is a view showing a result of measurement on an etching rate performed in Example 11 of the present invention.

FIG. 22 is a diagram showing a result of measurement on an etching rate performed in Example 10 of the present invention.

FIG. 23A is a conceptual diagram for explaining an etching process by a conventional method.

FIG. 23B is a conceptual diagram for explaining the etching process by the conventional method following FIG. 23A.

FIG. 24 is a sectional view showing a part of a magnetic head slider processed by a conventional method.

BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention will be described in detail based on examples and comparative examples carried out by the inventor.

Example 1 First, as shown in FIG. 1, a mask 2 was formed on a processed surface of a magnetic head slider substrate 1 (a surface facing a magnetic disk). In this embodiment, a mask having a pattern corresponding to the air bearing groove was formed by exposing and developing a dry film photoresist having a thickness of 75 μm.

In this embodiment, an inductively coupled plasma etching apparatus having a structure as shown in FIG. 3 was used. In this plasma etching apparatus, a main body 12 is formed by a hemispherical quartz glass bell jar.
The inside of 12 is an excitation unit 14. A single-turn antenna 15 is provided around the main body 12. The third
In the figure, for convenience of explanation, a part of the main body 12 is cut out and displayed.

The plasma etching apparatus includes an exhaust port 16 communicating with a turbo pump and a rotary pump, and a gas port 17 into which various gases can be introduced independently.

An electrode 13 also serving as a substrate holder is installed inside the main body 12 in a state insulated from the surroundings. The magnetic head slider substrate 1 (on which the mask 2 is formed) is fixed on the electrode 13. It is. Although not shown in the drawing, the electrode 13 is provided with a water cooling means for cooling heat generated at the time of etching.

The magnetic head slider substrate 1 was made of AC-2 type (trade name of Sumitomo Special Metals Co., Ltd.) aluminum oxide-titanium carbide composite ceramic material.

After fixing the magnetic head slider substrate 1 (on which the mask 2 is formed) on the electrode 13, the pump connected to the exhaust port 16 is operated to exhaust the inside of the excitation unit 14 to a pressure of 10 ⁻⁵ torr or less. .

Subsequently, through the gas port 17, as a reactive gas, 0.1.
About 8 mtorr of chlorine gas and about 1.2 mtorr of boron trichloride were introduced into the excitation unit 14. Further, 8 mtorr of argon gas is supplied as an inert gas through the gas port 17 to the excitation section.
Introduced within 14. Therefore, the total pressure of these introduced gases is 10 mtorr.

After that, the high frequency power supply 7 having the matching unit 8
By applying a high-frequency power of 1.2 kW and 13.56 MHz to 15, the introduced gas in the excitation unit 14 was plasma-excited. At the same time, a high frequency bias of 500 V, 100 kHz was applied from the bias power supply 9 to the electrode 13 to which the magnetic head slider substrate 1 was fixed, and etching of the magnetic head slider substrate 1 was started. In this embodiment, the etching time is 8
Minutes.

Here, the chlorine gas and the boron trichloride gas generate chlorine ions related to reactive etching, while the argon gas generates argon ions related to sputter etching. These ions are drawn into the surface to be processed of the magnetic head slider substrate 1 by the high frequency bias applied to the electrode 13.

After the etching process was completed, the mask 2 was removed from the surface of the magnetic head slider substrate 1 to be processed, and the depth of the etched portion was 2.3 μm.
From this result, it can be seen that the etching rate is 290 nm / min. In addition, no burrs were observed on the surface of the magnetic head slider substrate 1 to be processed.

(Example 2) The surface to be processed of the magnetic head slider substrate 1 is etched by using the same apparatus and material as in Example 1 except for changing the gas to be introduced into the excitation section 14 and using the same process and conditions. processed.

In this embodiment, chlorine gas (C
l ₂ ), boron trichloride gas (BCl ₃ ), carbon tetrachloride gas (CC
l _4), or a mixed gas (40% chlorine gas, using any of the three 60% boron chloride gas) were introduced into the excitation section 14 together with the argon gas (Ar) is an inert gas. The total pressure of the gas was adjusted to 10 mtorr.

FIG. 4 shows the relationship between the partial pressure ratio of the argon gas measured in Example 2 and the etching rate.

As is clear from FIG. 4, in all of the gas combinations, the etching rate generally increased as the partial pressure ratio of the argon gas increased, and showed a peak speed between 70 and 95% of the argon gas partial pressure ratio. ing. When the argon gas partial pressure ratio is close to 100%, the etching rate is rapidly reduced.

The etching rate is 100 to 200 nm / min even when no argon gas is added, which is 10 times that of a normal sputter etching method.
Although the value was almost doubled, the combination of carbon tetrachloride gas and argon gas reached a maximum of 360 nm / min or more. The reason why the etching rate is increased even in the region where the partial pressure ratio of the reactive gas is small is presumed to be that extremely high-density plasma was generated by inductively coupled plasma excitation applied to this embodiment.

FIG. 5 shows the relationship between the argon gas partial pressure ratio measured in Example 2 and the machined surface roughness.

As is apparent from FIG. 5, the roughness of the etched surface was significantly improved when the partial pressure ratio of the argon gas was 70% or more, although there was a slight difference depending on the type of the reactive gas. Even when the partial pressure ratio of the argon gas is smaller than 70%, the roughness of the processed surface is improved as compared with the conventional processing method, and the flying characteristics of the magnetic head slider are improved.

From the results shown in FIGS. 4 and 5, when the reliability of the magnetic head slider is particularly required, it is preferable to set the partial pressure ratio of the argon gas to 70% or more and 95% or less.

Regarding the generation of burrs on the surface to be processed, when carbon tetrachloride gas was used as the reactive gas, immediately after the end of the etching process, a slight redeposition layer was observed on the cross section of the resist mask, which was considered to be a polymer of carbon. . However, a step of removing the resist mask (hereinafter, referred to as a mask removing step)
The redeposited layer was easily removed and did not remain as burrs. No burrs were observed for other gas combinations.

Embodiment 3 Krypton gas is used as an inert gas to be introduced into the excitation section 14, and the other apparatus and materials are the same as those of Embodiment 1, and the same process and conditions are used and the processing surface of the magnetic head slider substrate 1 is processed. Was etched.

As a result, as shown in FIG. 6, both the etching rate and the processed surface roughness showed the same tendency as in the case of using the argon gas of Example 2. After the mask was removed, no burr was observed on the surface to be processed of the magnetic head slider substrate 1. As a result, it has been clarified that the inert gas is not limited to the argon gas, but various inert gases contributing to sputter etching can be applied to the method of the present invention.

Example 4 In this example, the magnetic head slider substrate was etched using an inductively coupled plasma etching apparatus having a configuration as shown in FIG.

In the plasma etching apparatus shown in FIG. 7, a ceiling surface of the excitation section 14 is formed by a quartz glass plate 18, and a single-turn antenna 15 is disposed above the excitation section. The other configuration is substantially the same as that of the plasma etching apparatus shown in FIG. 3, and thus the same reference numerals are given and the detailed description is omitted.

This plasma etching apparatus also excites the reactive gas and the inert gas introduced into the excitation section 14 by the action of high frequency. Then, ions generated by the plasma excitation are drawn into the magnetic head slider substrate 1 by the bias voltage applied to the electrode 13. Thereby, the reactive etching and the sputter etching can proceed at the same time.

In Example 4, the materials used and the steps were the same as those in Example 2 described above, and the following gas was introduced into the excitation unit 14. That is, in Example 4, any one of chlorine gas, boron trichloride gas, carbon tetrachloride gas, or a mixed gas (chlorine gas 40%, boron trichloride gas 60%) was used as the reactive gas. , Together with argon gas (inert gas). The total gas pressure is 10mtorr
Was adjusted.

In addition, a 13.56 Hz high frequency power of 1.2 kW was output to the upper antenna 15 and a 100 kHz bias of 500 V was applied to the electrode 13 to perform etching for 8 minutes.

As a result, almost the same results as in Example 2 were obtained as shown in FIG. 8 for the etching speed and FIG. 9 for the processed surface roughness. After the mask was removed, no burr was observed on the surface to be processed of the magnetic head slider substrate 1.

Example 5 In this example, a magnetic head slider substrate was etched using a parallel plate type reactive ion etching apparatus having a configuration as shown in FIG. The tenth
In the configuration of the figure, the same reference numerals are given to the same or similar parts as the configuration of FIG. 3 shown above.

The etching apparatus shown in FIG. 10 has a structure in which the gas introduced into the excitation section 14 is plasma-excited by the upper electrode 19 connected to the high-frequency power supply 7. This etching apparatus also excites the reactive gas and the inert gas introduced into the excitation unit 14 by the action of high frequency. Then, ions generated by the plasma excitation are drawn into the magnetic head slider substrate 1 by the bias voltage applied to the electrode 13. Thereby, the reactive etching and the sputter etching can proceed at the same time.

In Example 5, the materials used and the steps were the same as in Example 2 described above, and the following gas was introduced into the excitation section 14. That is, in Example 5, any one of chlorine gas, boron trichloride gas, carbon tetrachloride gas, or a mixed gas (chlorine gas 40%, boron trichloride gas 60%) was used as the reactive gas, and argon gas was used. Excitation unit with gas (inert gas)
Introduced within 14. The total pressure of the gas was adjusted to 10 mtorr.

In addition, a 13.56 MHz high frequency power of 1.2 kW was output to the upper electrode 19, and a 100 kHz bias of 500 V was applied to the electrode 13, and etching was performed for 8 minutes.

As a result, as shown in FIG. 11 for the etching rate and FIG. 12 for the roughness of the machined surface, the same tendency as in Example 2 was shown. However, the etching rate was about 100 nm / min at the maximum, which was slower than that in Example 2. It can be assumed that the reason why the etching rate was decreased in this way is that the density of the plasma excited in the excitation section was different from that of the apparatus used in the second embodiment. Even so, it is about four times faster than conventional sputter etching. After the mask was removed, no burr was observed on the surface to be processed of the magnetic head slider substrate 1.

Embodiment 6 In this embodiment, a magnetic head slider substrate was etched using a helicon wave plasma etching apparatus having a configuration as shown in FIG. In the structure of FIG. 13, the same or similar parts as those of the structure of FIG. 3 described above are denoted by the same reference numerals.

By outputting a high frequency of 13.56 MHz from the high frequency power supply 7 to the antenna 15 installed around the excitation section 14, the reactive gas and the inert gas introduced from the gas port 17 are plasma-excited, and m = 0. A mode plasma is generated. The density of the plasma 3 is increased by a solenoid coil 21 provided around the main body 12, and the plasma 3 is transported to the periphery of the magnetic head slider substrate 1.

The ions generated by the plasma excitation are
The magnetic head slider substrate 1 is drawn by the bias voltage applied to the magnetic head slider substrate 1. Thereby, the reactive etching and the sputter etching can proceed at the same time.

In Example 6, the materials used and the steps were the same as in Example 2 described above, and the following gas was introduced into the excitation section 14. That is, in Example 6, as the reactive gas, any of chlorine gas, boron trichloride gas, carbon tetrachloride gas, or a mixed gas (chlorine gas 40%, boron trichloride gas 60%) was used, and argon gas was used. Excitation unit with gas (inert gas)
Introduced within 14. The total pressure of the gas was adjusted to 10 mtorr.

In addition, a 13.56 MHz high frequency power of 1.2 kW was output to the upper antenna 15, and a 100 kHz bias of 500 V was applied to the electrode 13, and etching was performed for 8 minutes.

As a result, as shown in FIG. 14 for the etching rate and FIG. 15 for the roughness of the machined surface, the same tendency as in Example 2 was shown. After the mask was removed, no burr was observed on the surface to be processed of the magnetic head slider substrate 1.

Embodiment 7 In this embodiment, the magnetic head slider substrate was etched using an electron cyclotron resonance type plasma etching apparatus having a configuration as shown in FIG.
In the configuration of FIG. 16, the same or similar parts as those of the configuration of FIG. 3 or FIG. 13 described above are denoted by the same reference numerals.

The microwave 23 of 2.45 GHz output through the alumina plate 22 installed on the upper part of the excitation unit 14
Resonates at a magnetic field of 87.5 mT of magnetic flux density created by 1. Thus, the reactive gas and the inert gas introduced from the gas port 17 are excited by plasma.

The ions generated by the plasma excitation are
The magnetic head slider substrate 1 is drawn by the bias voltage applied to the magnetic head slider substrate 1. Thereby, the reactive etching and the sputter etching can proceed at the same time.

In Example 7, the materials used and the steps were the same as those in Example 2 described above, and the following gas was introduced into the excitation section 14. That is, in Example 7, any one of chlorine gas, boron trichloride gas, carbon tetrachloride gas, or a mixed gas (chlorine gas 40%, boron trichloride gas 60%) was used as the reactive gas, and argon gas was used. Excitation unit with gas (inert gas)
Introduced within 14. The total pressure of the gas was adjusted to 10 mtorr.

Further, a microwave of 600 W was transmitted to the waveguide 24, and a 100 kHz bias of 500 V was applied to the electrode 13, and etching was performed for 8 minutes.

As a result, as shown in FIG. 17 for the etching rate and in FIG. 18 for the processed surface roughness, the same tendency as in Example 2 was shown. After the mask was removed, no burr was observed on the surface to be processed of the magnetic head slider substrate 1.

In the above Examples 1 to 7, the first method of the present invention was carried out using a chlorine-based gas (reactive gas).
As is clear from these examples, the first method of the present invention is to excite the plasma by an appropriate method of the introduced gas and to apply ions in the plasma to the magnetic head slider substrate (object to be processed) by applying a bias voltage. The magnetic head slider substrate can be processed quickly and with high accuracy by using various etching apparatuses having a configuration that can be drawn into the magnetic head slider substrate.

Note that the frequency of the high frequency or microwave used for plasma excitation or bias is not limited to the value set in the above embodiment, but can be adjusted as appropriate.

(Comparative Example 1) The first method of the present invention was applied to a chlorine-based gas (reactive gas).
As a comparative example, the magnetic head slider substrate was etched by a conventional sputter etching method using an argon gas in order to clarify the effect when the method was performed using the method described above.

The apparatus, material, process, and conditions other than the gas used in the embodiment were the same as those in the above embodiments, and sputter etching was realized by introducing only argon gas into the excitation section. This corresponds to a case where the partial pressure ratio of the argon gas is 100% in each of the above-described embodiments using the argon gas as the inert gas.

That is, FIG. 4, FIG. 5, FIG. 8, FIG.
In FIG. 12, FIG. 14, FIG. 14, FIG. 15, FIG. 17, and FIG.
The result of processing by the conventional sputter etching method is shown.

As a result, the etching rate is lower in each case than in each embodiment of the present invention. The roughness of the etched surface is
Although not numerically large, the lifting of the titanium carbide crystal was partially observed, leaving the possibility of damaging the magnetic disk due to the detachment of the floating crystal. Further, on the surface to be processed of the magnetic disk slider substrate, a re-adhesion layer having the same composition as the substrate is deposited, and the re-adhesion layer remains even after the resist removing step and the cleaning step. Was left as a burr.

Example 8 In Example 8, the first method of the present invention described above was performed using a bromine-based gas (reactive gas).

In the eighth embodiment, the inductively coupled plasma etching apparatus (see FIG. 3) used in the first embodiment is used.
The materials used and the operating conditions were the same as in Example 1 above.

In this embodiment, a bromine gas (B
r ₂ ), boron tribromide gas (BBr ₃ ), or hydrogen bromide gas (HBr) was used and introduced into the excitation section 14 together with an inert gas, argon gas (Ar). The total pressure of the gas was adjusted to 10 mtorr.

The reactive gas and the inert gas introduced into the excitation unit 14 are plasma-excited by the action of high frequency. And
The ions generated by the plasma excitation are drawn into the magnetic head slider substrate 1 by the bias voltage applied to the electrode 13. Thereby, the reactive etching and the sputter etching proceeded simultaneously.

FIG. 19 shows the relationship between the partial pressure ratio of argon gas measured in Example 8 and the etching rate.

As is clear from FIG. 19, in any of the gas combinations, the etching rate increases as the partial pressure ratio of the argon gas generally increases, and the etching rate increases to 200 nm / min or more between 70 to 95% of the argon gas partial pressure ratio. Shows the peak velocity of And when the argon gas partial pressure ratio is close to 100%,
The etching rate is rapidly decreasing.

In addition, the etching rate was 160 to 190 nm even when argon gas was not added (partial pressure of argon gas was 0%),
It can be confirmed that it is much faster than the normal sputter etching method. This corresponds to the case where the second method of the present invention is performed using a bromine-based gas.

FIG. 20 shows the relationship between the argon gas partial pressure ratio measured in Example 8 and the machined surface roughness.

As is apparent from FIG. 20, the roughness of the etched surface was significantly improved at a partial pressure ratio of argon gas of 70% or more, although there was a slight difference depending on the type of the reactive gas. Even when the partial pressure ratio of the argon gas is smaller than 70%, the roughness of the processed surface is improved as compared with the conventional processing method, and the flying characteristics of the magnetic head slider are improved.

From the results shown in FIGS. 19 and 20, when the reliability of the magnetic head slider is particularly required, it is preferable to set the partial pressure ratio of the argon gas to 70% or more and 95% or less.

After removing the mask, no burr was observed on the surface to be processed of the magnetic head slider substrate 1.

(Comparative Example 2) The first method of the present invention is applied to a bromine-based gas (reactive gas).
As a comparative example, the magnetic head slider was etched by a conventional sputter etching method using an argon gas in order to clarify the effect of the case where the method was performed using.

The apparatus, materials, steps, and conditions other than the used gas used in the embodiment were the same as those in Example 8 described above, and sputter etching was realized by introducing an argon gas into the excitation section.

As a result, the etching rate was 30 nm / min, which was not more than 1/20 of the maximum etching rate obtained in Example 9. Further, on the surface to be processed of the magnetic disk slider substrate, a re-adhesion layer having the same composition as that of the substrate is deposited, and the re-adhesion layer remains even after the resist removing step and the cleaning step. Was left as a burr. This is probably because argon gas is an inert gas, so that only plasma-excited sputter etching by ion bombardment can be expected.

Embodiment 9 In Embodiments 9 to 11, the magnetic head slider substrate was etched based on the above-described second method of the present invention.

In the ninth embodiment, the inductively coupled plasma etching apparatus (see FIG. 3) used in the first embodiment was used, and the process, materials used, and operating conditions were the same as those in the first embodiment. In Example 9, chlorine gas as a reactive gas was introduced into the excitation unit 14 from the gas port 17, and the chlorine gas was plasma-excited.

Here, the chlorine gas generates chlorine ions related to the reactive etching. The chlorine ions are drawn into the surface to be processed of the magnetic head slider substrate 1 by the high frequency bias applied to the electrode 13. The etching time was 8 minutes.

After the etching process was completed, the mask was removed from the processed surface of the magnetic head slider substrate, and the depth of the etched portion was 0.9 μm. From this result, it can be seen that the etching rate is 113 nm / min.

After completion of the etching process, a redeposition layer 15 was observed on the side surface of the mask 2 as schematically shown in FIG.
However, as a result of analyzing the redeposition layer 15, it was found that the substance was mainly a chloride. Therefore, in the mask removing step,
The redeposition layer 15 was easily removed and did not remain as burrs.

(Embodiment 10) The processing target surface of the magnetic head slider substrate 1 is etched by using the same apparatus and material as in Embodiment 9 except for changing the gas to be introduced into the excitation section 14 and using the same process and conditions. processed.

In Example 10, a mixed gas of chlorine and carbon tetrachloride was used as a reactive gas, and was introduced into the excitation unit 14. The partial pressure of carbon tetrachloride in the total pressure of the introduced mixed gas was changed in the range of 0 to 100%, and the relationship between the partial pressure and the etching rate was measured.

FIG. 22 shows the relationship between the partial pressure of carbon tetrachloride measured in Example 10 and the etching rate.

As is clear from FIG. 22, the partial pressure of carbon tetrachloride is 60%.
, It was found that the etching rate tended to increase as the partial pressure increased. When the partial pressure of carbon tetrachloride is 60%, the maximum etching rate (640 nm /
Min). This is a rate at which a depth of 5 μm or more can be etched in 8 minutes. However, when the partial pressure of carbon tetrachloride exceeds 60%, the etching rate decreases, and when the partial pressure exceeds 80%, a substance which appears to be a brown-colored polymer appears on the surface to be processed of the magnetic head slider substrate 1. Became deposited, and the surface roughness was significantly reduced.

For this reason, the partial pressure of carbon tetrachloride in the total pressure of the introduced mixed gas is preferably 80% or less,
It can be seen that the most remarkable effect is observed around%.

When the partial pressure of carbon tetrachloride is 80% or less, after the mask is removed, the surface to be processed of the magnetic head slider substrate 1 is
No burrs were found.

(Embodiment 11) This embodiment 11 uses the inductively coupled plasma etching apparatus (see FIG. 3) used in the previous embodiment 1 to perform the steps
The materials used and the operating conditions were the same as in Example 1 above. In Example 11, a mixed gas of chlorine and boron trichloride was introduced as a reactive gas into the excitation unit 14 from the gas port 17, and the mixed gas was plasma-excited.

Here, the mixed gas of chlorine and boron trichloride generates ions related to reactive etching. This ion
The magnetic head slider substrate 1 is drawn into the surface to be processed by the high frequency bias applied to the electrode 13.

In Example 11, the partial pressure of boron trichloride in the total pressure of the mixed gas introduced into the excitation unit 14 was changed in the range of 0 to 100%, and the relationship between the partial pressure and the etching rate was measured.

FIG. 21 shows the relationship between the partial pressure of boron trichloride measured in Example 11 and the etching rate.

As is clear from FIG. 21, the partial pressure of boron trichloride was 60
%, The etching rate tends to increase as the partial pressure increases. When the partial pressure of boron trichloride is 60%, the maximum etching rate (600 n
m / min). This is a rate at which a depth of less than 5 μm can be etched in 8 minutes.

When the partial pressure of boron trichloride exceeded 60%, the etching rate tended to decrease gradually. Nevertheless, when boron trichloride was set to 100%, that is, when only boron trichloride was introduced as a reactive gas into the excitation section 14, a high processing speed of 400 nm / min was exhibited.

After removing the mask, no burr was observed on the surface to be processed of the magnetic head slider substrate 1.

Comparative Example 3 In order to clarify the effect of the second method of the present invention,
As a comparative example, a magnetic head slider was etched by a conventional sputter etching method using argon gas.

The apparatus, materials, steps, and conditions other than the used gas used in the embodiment were the same as those in the above-described ninth to eleventh embodiments, and sputter etching was realized by introducing an argon gas into the excitation unit.

As a result, the etching rate was 30 nm / min.
0 or 20 of the maximum etching rate obtained in Example 11.
It was less than one part. Further, on the surface to be processed of the magnetic disk slider substrate, a re-adhesion layer having the same composition as that of the substrate is deposited, and the re-adhesion layer remains even after the resist removing step and the cleaning step. Was left as a burr. This is because argon gas is an inert gas,
It is considered that only sputter etching by ion bombardment can be expected even when plasma is excited. This confirmed the effectiveness of using chlorine gas, a mixed gas of chlorine and carbon tetrachloride, a boron trichloride gas, or a mixed gas of chlorine and boron trichloride.

Dashed lines a shown in FIGS. 21 and 22, respectively, indicate the etching rates measured in Comparative Example 3.

The above-described second and eleventh embodiments both use an inductively coupled plasma etching apparatus having the structure shown in FIG. Then, in Example 2 (see FIG. 4), a result of etching by introducing a mixed gas of 60% boron trichloride and 40% chlorine and an argon gas into the excitation section 14 and performing an etching process is shown. When the partial pressure is 0%, the etching rate is 200 nm / min. In other words, the atmosphere of argon having a partial pressure of 0% is equivalent to boron trichloride 60%.
%, And only a mixed gas of 40% chlorine was introduced into the excitation unit 14 to perform the etching process.

On the other hand, looking at the result of Example 11 in which a mixed gas of boron trichloride and chlorine was introduced into the excitation section 14 and etching was performed (see FIG. 21), it was found that the partial pressure of boron trichloride was 60% ( That is, the proportion of boron trichloride 60% and chlorine 40%)
The etching rate indicates 600 nm / min.

Thus, the difference in the measurement results of the examples performed using the same gas is considered to be due to the change in the size of the plasma etching apparatus used. That is, the diameters of the main body 12 and the antenna 15 were changed during the execution of each embodiment. As a result, it is presumed that the volume of the excitation unit 14 and the distance between the magnetic head slider substrate 1 on the electrode 13 and the antenna 15 are different, and the excited state of the plasma is changed.

Needless to say, each of the examples and the comparative example using the conventional sputter etching method were performed using the same size apparatus.

According to the magnetic head slider processing method of the present invention, various methods can be used to excite the introduced gas into plasma by an appropriate method and to draw ions in the plasma into the magnetic head slider substrate (processing target) by applying a bias voltage. It can be performed using an etching apparatus. For example, Embodiments 8 to 11 are described in FIG. 7, FIG.
It can also be carried out using the etching apparatus shown in FIGS.

Further, the frequency of the high frequency or microwave used for plasma excitation or bias is not limited to the value set in the above-described embodiment, but can be adjusted as appropriate.

Further, the magnetic head slider substrate can be formed of various ceramic materials containing alumina and titanium carbide as main components. The processing shape of the air bearing groove formed in the magnetic head slider substrate can be arbitrarily designed, and the present invention is also effective for processing a slider in a contact type or pseudo contact type magnetic head such as a vertical magnetic head.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to obtain a magnetic head slider which has excellent reliability and stable flying characteristics, and can greatly contribute to a higher recording density of an external storage device.

Continuation of the front page (56) References JP-A-4-132011 (JP, A) JP-A-4-129014 (JP, A) JP-A-61-123141 (JP, A) JP-A-6-236860 (JP) JP-A-4-56785 (JP, A) JP-A-5-136100 (JP, A) JP-A-5-6876 (JP, A) (58) Fields studied (Int. Cl. ⁶ , DB G11B 5/60 G11B 21/21 101

Claims (3)

(57) [Claims] A mask having a predetermined pattern is formed on a surface to be processed of a magnetic head slider substrate containing aluminum oxide and titanium carbide as main components, and the magnetic head slider substrate on which the mask is formed is placed in an etching apparatus. After being placed on the electrode, a reactive gas and an argon gas, which is an inert gas, are introduced into the excitation unit of the etching apparatus to excite these gases into plasma, and by applying a high-frequency bias to the electrode, The reactive gas ions and the inert gas ions obtained by the plasma excitation are drawn into the magnetic head slider substrate, and the reactive etching by the reactive gas ions and the sputter etching by the inert gas ions proceed simultaneously. A method for processing a head slider, wherein a salt is used as the reactive gas. Gas, carbon tetrachloride gas, boron trichloride gas, mixed gas of chlorine and boron trichloride, bromine gas, hydrogen bromide gas, or boron tribromide gas. A method of processing a magnetic head slider, wherein a partial pressure ratio of the argon gas to pressure is set to 70% or more and 95% or less. 2. A mask having a predetermined pattern is formed on a surface to be processed of a magnetic head slider substrate containing aluminum oxide and titanium carbide as main components, and the magnetic head slider substrate on which the mask is formed is placed in an etching apparatus. After installing on the electrode, a mixed gas of chlorine and carbon tetrachloride is introduced as a reactive gas into the excitation section of the etching apparatus to excite the reactive gas into plasma and to apply a high frequency bias to the electrode. According to the magnetic head slider processing method, the reactive gas ions obtained by the plasma excitation are drawn into the magnetic head slider substrate, and sputter etching is performed by reactive etching with the reactive gas ions. The partial pressure of carbon tetrachloride in the total pressure of the mixed gas introduced into Method for processing a magnetic head slider according to claim Rukoto. 3. A mask having a predetermined pattern is formed on a surface to be processed of a magnetic head slider substrate containing aluminum oxide and titanium carbide as main components, and the magnetic head slider substrate on which the mask is formed is placed in an etching apparatus. After installing on the electrode, a mixed gas of chlorine and boron trichloride is introduced as a reactive gas into the excitation section of the etching apparatus to excite the reactive gas into plasma and to apply a high frequency bias to the electrode. According to the magnetic head slider processing method, the reactive gas ions obtained by the plasma excitation are drawn into the magnetic head slider substrate, and sputter etching is performed by reactive etching with the reactive gas ions. The partial pressure of the boron trichloride in the total pressure of the mixed gas introduced into Method for processing a magnetic head slider, characterized in that a.