JP3823882B2 - Method for manufacturing thin film magnetic head having magnetoresistive effect element - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing a thin film magnetic head having a magnetoresistive effect (MR) element that reads a magnetic field intensity of a magnetic recording medium or the like as a signal.
[0002]
[Prior art]
As the capacity of a hard disk drive (HDD) is reduced, a thin film magnetic head with high sensitivity and high output is required. In order to meet this demand, the hard characteristics of the GMR head having the giant magnetoresistive effect (GMR) element, which is the current product, have been improved. On the other hand, the tunnel magnetism can be expected to have a resistance change rate more than twice that of the GMR head. Development of a TMR head having a resistance effect (TMR) element has been energetically performed.
[0003]
The TMR head and the general GMR head have different head structures due to the difference in the direction in which the sense current flows. A CIP (Current In Plane) structure has a head structure that allows a sense current to flow parallel to the laminated surface (film surface), as in a general GMR head, and a sense current that is perpendicular to the film surface, such as a TMR head. The flowing head structure is called a CPP (Current Perpendicular to Plane) structure.
[0004]
In recent years, GMR heads having a CPP structure instead of a CIP structure have been developed. For example, Japanese Patent Application Laid-Open No. 5-275769 describes a GMR head having such a CPP structure. JP-A-4-360009, JP-A-5-90026, and JP-A-9-129445 include a plurality of magnetic layers stacked via nonmagnetic layers (Cu, Ag, Au, etc.). A CPP structure GMR head having an antiferromagnetically coupled magnetic multilayer film is described.
[0005]
As a recent GMR head having a CPP structure, a GMR head having a spin valve magnetic multilayer film (including a specular type magnetic multilayer film and a dual spin valve type magnetic multilayer film) similar to the case of a CIP structure GMR head is also being studied. .
[0006]
In the case of forming a GMR head or a TMR head having such a CPP structure, conventionally, a lift-off method, a contact hole method, or the like has been used.
[0007]
FIG. 1 is a cross-sectional view showing a partial process of forming a GMR head having a CPP structure by a lift-off method.
[0008]
As shown in FIG. 2A, first, a lower electrode film 11 and an MR multilayer film 12 ′ are sequentially laminated on an insulating film 10 formed on a substrate (not shown).
[0009]
Next, as shown in FIG. 2B, a two-layer photoresist pattern 13 is formed thereon, and as shown in FIG. 2C, the MR multilayer film 12 'is patterned by ion milling to form an MR multilayer. A body 12 is obtained.
[0010]
Next, an insulating film 14 'is formed as shown in FIG. 4D, and the photoresist pattern 13 is peeled off as shown in FIG. 5E, that is, the insulating film 14 is obtained by lift-off.
[0011]
Thereafter, as shown in FIG. 5F, the upper electrode film 15 is formed thereon.
[0012]
FIG. 2 is a sectional view showing a partial process of forming a GMR head having a CPP structure by a contact hole method.
[0013]
As shown in FIG. 2A, first, a lower electrode film 21 and an MR multilayer film 22 ′ are sequentially laminated on an insulating film 20 formed on a substrate (not shown).
[0014]
Next, as shown in FIG. 6B, a photoresist pattern 23 is formed thereon, and as shown in FIG. 6C, the MR multilayer film 22 ′ is patterned by ion milling to form the MR multilayer body 22. obtain.
[0015]
Next, as shown in FIG. 4D, after the photoresist pattern 23 is peeled off, an insulating film 24 ′ is formed.
[0016]
Next, as shown in FIG. 5E, a photoresist pattern 26 having an opening 26a corresponding to the contact hole is formed on the insulating film 24 '.
[0017]
Next, as shown in FIG. 5F, ion milling of the insulating film 24 'is performed to obtain the insulating film 24 having the contact hole 24a on the MR multilayer 22, and then the photoresist pattern 26 is peeled off.
[0018]
Thereafter, an upper electrode film 25 is formed thereon as shown in FIG.
[0019]
[Problems to be solved by the invention]
In the lift-off method shown in FIG. 1, it is necessary that the insulating film 14 ′ adheres to the side wall of the step portion of the two-layer photoresist pattern 13 and the insulating film 14 ′ is not connected across the step portion. For this reason, the lift-off property is usually improved by forming an eaves-like undercut using a two-layer photoresist pattern.
[0020]
However, when the undercut amount of the photoresist pattern 13 is small, an insulating film is deposited on the side wall of the base portion 13a of the two-layer photoresist pattern 13, and unnecessary deposition is performed around the position where the photoresist pattern 13 exists after lift-off. Burr that is a thing occurs. Increasing the undercut amount suppresses the occurrence of such burrs, but the resist width of the base portion 13a, which is the undercut portion, becomes extremely narrow, and pattern collapse or the like may occur.
[0021]
In addition, as shown in FIG. 1E, the insulating film 14 that wraps around the undercut portion overlaps the upper surface of the MR multilayer 12 and the track width becomes unclear. Limits arise. Since the overlap in the lift-off method is about 100 nm, when the track width reaches a level of 200 nm or less, for example, 100 nm, as in recent TMR elements and GMR elements, the functions as GMR elements and TMR elements are no longer available. I can't expect anything.
[0022]
In the contact hole method shown in FIG. 2, two photo processes relating to the resist pattern are performed. Therefore, the overlap generated by the misalignment caused by this is about 30 nm. As with the lift-off method, this is not so large that it can be ignored.
[0023]
In general, in the MR multilayer of TMR elements and GMR elements, the free layer is located in the middle of the MR multilayer, and the width defines the track width. Therefore, when the MR multilayer body is formed by ion milling using a conventional photoresist as a mask, the skirt of the MR multilayer body spreads and the effective track width is increased. Ideally, it is desirable that the side wall of the MR multilayer is perpendicular to the substrate surface. As a method for realizing this, ion milling using a hard mask, reactive ion etching (RIE) method, or the like is used. Exists. However, none of these can be used for the lift-off method in principle.
[0024]
As described above, according to the prior art, it is extremely difficult to realize a GMR head or a TMR head having a CPP structure with a track width of 200 nm or less, and it is required to establish a new method that can avoid these. Yes.
[0025]
Accordingly, an object of the present invention is to provide a method of manufacturing a thin film magnetic head having an MR element, which can easily manufacture an MR element having a track width of 200 nm or less and a current flowing in a direction perpendicular to the laminated surface. is there.
[0026]
[Means for Solving the Problems]
  According to the present invention, an MR multilayer is formed on the lower electrode film, and a current flows in a direction perpendicular to the lamination surface, and an insulating film is laminated on the formed MR multilayer and the lower electrode film.Laminated insulation filmAt least the upper surface of the MR laminate is exposedTo the frontUsing gas cluster ion beam (GCIB)Flatten,The planarized insulating film is 2 nm / min or less until at least the upper surface of the MR laminate is exposed.Low rate ion beam etching with low etching rate (low rate IBE)Accordingly, there is provided a method for manufacturing a thin film magnetic head having an MR element which is flattened and forms an upper electrode film on the flattened insulating film and MR laminated body.
[0027]
  Instead of the lift-off method, an insulating film is stacked on the MR multilayer and the lower electrode film, and the insulating film is stacked until at least the upper surface of the MR multilayer is exposed.By processing with GCIB and low rate IBE with low etching rateBy planarizing, the MR laminated body and the insulating film around it are formed.
[0028]
When this method is used, it is possible to use a normal straight resist pattern having no reverse taper, so that it is possible to form a finer MR laminate than when formed using the lift-off method.
[0029]
In addition, since RIE, a hard mask, and the like that can reduce the occurrence of skirting when milling the MR laminate can be utilized, it is possible to greatly contribute to the improvement of the shape of the MR laminate.
[0030]
Furthermore, the occurrence of burrs and overlaps in the insulating film cannot occur, and the stricter definition of the track width is possible. Therefore, an MR element in which the track width is 200 nm or less and a current flows in a direction perpendicular to the laminated surface can be easily obtained. Can be manufactured.
[0031]
It is preferable to form an MR multilayer by laminating an MR multilayer on the lower electrode film, forming a mask on the laminated MR multilayer, patterning the MR multilayer, and then removing the mask. .
[0032]
An MR multilayer film is laminated on the lower electrode film, a mask is formed on the laminated MR multilayer film, the MR multilayer film is patterned, and then this mask is used as a cap layer of the MR multilayer body. It is also preferable to form
[0033]
  Flattening,further,Low-angle ion beam etching (low-angle ion beam etching)Low angleIBE)WhenIt is preferable to carry out by.
[0036]
The angle formed between the incident beam and the laminated surface in the low angle IBE is preferably 0 to 40 degrees.
[0039]
The planarization is preferably terminated by managing the planarization processing time and / or detecting the end point. More preferably, this end point detection is performed using a secondary ion mass spectrometer (SIMS).
[0040]
The MR laminate is a TMR laminate, a CPP-structured GMR laminate, or a TMR laminate or a CPP-structured GMR laminate including a bias layer that defines a magnetization direction with respect to the free layer. preferable.
[0041]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 3A is a cross-sectional view showing a partial process of forming a GMR head having a TMR head or a CPP structure as an embodiment of the present invention.
[0042]
First, as shown in FIG. 2A, a lower electrode film 31 that also serves as a magnetic shield film and an MR multilayer film 32 'are sequentially stacked on an insulating film 30 formed on a substrate (not shown).
[0043]
Next, as shown in FIG. 2B, a photoresist pattern 33 having straight sidewalls is formed thereon.
[0044]
Next, as shown in FIG. 3C, the MR multilayer 32 having a thickness of about 35 to 55 nm is formed by IBE, RIE, reactive ion beam etching (RIBE) or sputtering using the photoresist pattern 33 as a mask. ′ Is patterned to obtain an MR multilayer 32 whose upper surface is a junction.
[0045]
The MR multilayer 32 includes a TMR multilayer, a CPP-structured GMR multilayer, a TMR multilayer including a bias layer that defines the magnetization direction for the free layer, or a CPP-structured GMR multilayer, and an antiferromagnetically coupled magnetic multilayer film. For example, a CPP structure GMR multilayer having a specular spin valve magnetic multilayer film, or a CPP structure GMR multilayer having a dual spin valve magnetic multilayer film.
[0046]
Next, as shown in FIG. 4D, after removing the photoresist pattern 33 as a mask, the junction portion becomes convex, for example, Al having a film thickness of about 50 to 100 nm.₂O₃Or SiO₂An insulating film 34 'such as is formed on the entire surface. The film thickness of the insulating film 34 ′ is preferably equal to or larger than the film thickness of the MR multilayer 32 in order to perform reliable insulation.
[0047]
Thereafter, as shown in FIG. 5E, the insulating film 34 ′ is flattened until at least the upper surface (junction) of the MR multilayer 32 is exposed by performing low-angle IBE in which a beam is incident on the laminated surface at a low angle. In other words, the MR multilayer 32 is cueed, and the insulating film 34 is obtained.
[0048]
In this case, the low angle IBE is preferably such that the angle formed between the incident ion beam and the laminated surface is 0 to 40 degrees. If the angle is larger than 40 degrees, flattening becomes difficult. The angle formed between the incident ion beam and the laminated surface is more preferably 0 to 30 degrees, and most preferably 0 to 20 degrees. The end of the flattening may be controlled by managing the flattening processing time, or may be controlled by performing end point detection using SIMS, for example. When endpoint detection is performed using SIMS, since the area of the MR multilayer 32 is very small, detection is facilitated by previously stacking an endpoint detection film. That is, when the insulating film 34 'is formed, the film is formed to the same or slightly lower height as the MR multilayer 32, and an extremely thin layer, for example, Co, Mn, Ti, Ta, Cr, etc. is used for end point detection. If the insulating film 34 ′ is formed again after providing the film, detection by SIMS becomes easy.
[0049]
As an example of the low angle IBE, the etching conditions are as follows:
Beam incident angle: 20 degrees
Acceleration voltage: 300V
Beam current: 0.35 mA / cm²
Ar gas pressure: 2.4 × 10^-4Torr
Substrate temperature: 30 ° C
Etching time: about 15 minutes.
[0050]
Thereafter, as shown in FIG. 4F, an upper electrode film 35 that also serves as a magnetic shield film is formed on the planarized insulating film 34 and MR multilayer 32.
[0051]
A hard mask may be used instead of the photoresist pattern 33. When a conductive hard mask is used, the hard mask may be left without being removed and used as a cap layer of the MR multilayer 32.
[0052]
FIG. 3b is a cross-sectional view showing in more detail the actual planarization process in the embodiment of FIG. 3a.
[0053]
As shown in FIGS. 4A to 4C, in this embodiment, when the insulating film 34 is flattened, the upper portion of the cap layer 32f of the MR multilayer 32 is actually etched, and this portion is not etched. A mountain-shaped protrusion 32f ′ is formed by a cap layer having a height of several percent of the width (junction width) of the MR multilayer 32. Therefore, as the cap layer 32f of the MR multilayer 32, it is desirable to stack a layer thicker than the height of the convex portion 32f ′.
[0054]
FIG. 4 a is a cross-sectional view schematically showing an example of the layer structure of the TMR head formed as described above.
[0055]
As shown in the figure, a lower electrode film 31 that also serves as a magnetic shield film is laminated on an insulating film 30 to a film thickness of about 2000 nm, on which an underlayer 32a having a film thickness of 0 to about 20 nm, A pinned layer 32b having a thickness of 10 to 20 nm, a pinned layer 32c having a thickness of about 5 to 6 nm, a tunnel barrier layer 32d having a thickness of about 1 nm, and a free layer 32e having a thickness of about 4 to 6 nm; An MR multilayer 32 is formed by sequentially laminating a cap layer 32f having a film thickness of about 5 to 10 nm, and an upper electrode film 35 that also serves as a magnetic shield film is laminated thereon to a film thickness of about 2000 nm. The insulating film 34 is formed so as to surround the periphery of the MR multilayer 32. The underlayer 32a having a thickness of 0 nm corresponds to the case where there is no underlayer.
[0056]
In the case of the GMR head having the CPP structure, the other configuration is the same as that of the TMR head except that a nonmagnetic metal layer having a thickness of about 2 to 5 nm is formed in the tunnel barrier layer 32d. .
[0057]
The cap layer 32f is preferably made of one or more of tantalum, rhodium, ruthenium, osmium, tungsten, palladium, platinum, and gold.
[0058]
FIG. 4B is a cross-sectional view schematically showing another example of the layer structure of the TMR head.
[0059]
An example of this is when the TMR stack includes a bias layer that defines the magnetization direction for the free layer. As shown in the figure, a lower electrode film 31 that also serves as a magnetic shield film is laminated on an insulating film 30 to a film thickness of about 2000 nm, on which an underlayer 32a having a film thickness of 0 to about 20 nm, A pinned layer 32b having a thickness of 10 to 20 nm, a pinned layer 32c having a thickness of about 5 to 6 nm, a tunnel barrier layer 32d having a thickness of about 1 nm, and a free layer 32e having a thickness of about 4 to 6 nm; An MR stack in which a nonmagnetic metal layer 32g having a thickness of about 0.1 to 3 nm, an antiferromagnetic layer 32h having a thickness of about 10 nm, and a cap layer 32f having a thickness of about 5 to 10 nm are sequentially stacked. A body 32 is formed, and an upper electrode film 35 that also serves as a magnetic shield film is laminated thereon to a thickness of about 2000 nm. The insulating film 34 is formed so as to surround the periphery of the MR multilayer 32. The underlayer 32a having a thickness of 0 nm corresponds to the case where there is no underlayer.
[0060]
In the case of the GMR head having the CPP structure, the other configuration is the same as that of the TMR head except that a nonmagnetic metal layer having a thickness of about 2 to 5 nm is formed in the tunnel barrier layer 32d. .
[0061]
As described above, according to the present embodiment, the insulating film 34 ′ is stacked on the MR multilayer 32 and the lower electrode film 31, and this insulating film 34 ′ is exposed until at least the upper surface of the MR multilayer 32 is exposed by the low-angle IBE. Is planarized to form the MR stack 32 and the insulating film 34 around it.
[0062]
When this method is used, it is possible to use a normal straight resist pattern or hard mask having no reverse taper, so that it is possible to form a finer MR laminate than when formed using the lift-off method. . In addition, since RIE, a hard mask, or the like that can reduce the occurrence of skirting when the MR laminate 32 is milled can be utilized, it can greatly contribute to the improvement of the shape of the MR laminate 32. Furthermore, the occurrence of burrs, overlaps, etc. in the insulating film 34 cannot occur, and a stricter track width can be defined. Therefore, an MR element having a track width of 200 nm or less can be easily manufactured. Actually, a TMR element having good output characteristics with a track width of 100 nm could be manufactured.
[0063]
FIG. 5 is a cross-sectional view showing a partial process of forming a GMR head having a TMR head or a CPP structure as another embodiment of the present invention.
[0064]
First, as shown in FIG. 2A, a lower electrode film 51 that also serves as a magnetic shield film and an MR multilayer film 52 ′ are sequentially stacked on an insulating film 50 formed on a substrate (not shown).
[0065]
Next, as shown in FIG. 2B, a photoresist pattern 53 having straight side walls is formed thereon.
[0066]
Next, as shown in FIG. 4C, the MR multilayer film 52 'is patterned by IBE, RIE, RIBE or sputtering using the photoresist pattern 53 as a mask, and the upper surface of the MR multilayer body becomes a junction. 52 is obtained.
[0067]
The MR multilayer 52 includes a TMR multilayer, a CPP-structured GMR multilayer, a TMR multilayer including a bias layer that defines the magnetization direction for the free layer, or a CPP-structured GMR multilayer, and an antiferromagnetically coupled magnetic multilayer film. For example, a CPP structure GMR multilayer having a specular spin-valve magnetic multilayer film, or a CPP structure GMR multilayer having a dual spin-valve magnetic multilayer film.
[0068]
Next, as shown in FIG. 3D, after removing the photoresist pattern 53 as a mask, an insulating film 54 ″ having a convex junction is formed on the entire surface. The film thickness of the insulating film 54 ″ is preferably equal to or larger than the film thickness of the MR multilayer 52 in order to perform reliable insulation.
[0069]
Thereafter, as shown in FIG. 5E, the insulating film 54 ″ is formed until at least the upper surface (junction) of the MR multilayer 52 is exposed by performing low-angle IBE in which a beam enters the laminated surface at a low angle. To obtain an insulating film 54 '.
[0070]
In this case, the low angle IBE is preferably such that the angle formed between the incident ion beam and the laminated surface is 0 to 40 degrees. If the angle is larger than 40 degrees, flattening becomes difficult. The angle formed between the incident ion beam and the laminated surface is more preferably 0 to 30 degrees, and most preferably 0 to 20 degrees. The end of planarization is controlled by managing the planarization processing time.
[0071]
As an example of the low angle IBE, the etching conditions are as follows:
Beam incident angle: 20 degrees
Acceleration voltage: 300V
Beam current: 0.35 mA / cm²
Ar gas pressure: 2.4 × 10^-4Torr
Substrate temperature: 30 ° C
Etching time: about 12 minutes.
[0072]
Next, as shown in FIG.₂The insulating film 54 ′ is flattened until at least the upper surface (junction) of the MR multilayer body 52 is exposed by performing low rate IBE with an etching rate of 2 nm / min or less). The insulating film 54 is obtained. The end of planarization may be controlled by managing the planarization processing time, but it is desirable to easily detect the end point using, for example, SIMS. Note that when endpoint detection is performed using SIMS, since the area of the MR multilayer 52 is very small, detection is facilitated by previously stacking an endpoint detection film. That is, when forming the insulating film 54 ″, the film is formed to the same or slightly lower height as the MR multilayer 52, and a very thin end point detection film is provided thereon, and then the insulating film 54 ″ is formed again. If film formation is performed, detection by SIMS becomes easy.
[0073]
As an example of low-rate IBE, the etching conditions are as follows:
Beam incident angle: 90 degrees
Acceleration voltage: 250V
Beam current: 0.1 mA / cm²
Ar gas pressure: 2 × 10^-4Torr
Substrate temperature: 50 ° C
Etching time: about 10 minutes.
[0074]
Thereafter, as shown in FIG. 5G, an upper electrode film 55 that also serves as a magnetic shield film is formed on the planarized insulating film 54 and MR multilayer 52.
[0075]
A hard mask may be used in place of the photoresist pattern 53. When a conductive hard mask is used, the hard mask may be left without being removed and used as a cap layer of the MR multilayer 52.
[0076]
Each film, the film thickness of each layer, the constituent materials, and the like in this embodiment are the same as those in the embodiment of FIG. 3a. The structure of the MR stack 52 is the same as that of the embodiment of FIG. 3a.
[0077]
According to the present embodiment, the insulating film 54 ″ is stacked on the MR multilayer 52 and the lower electrode film 51, the insulating film 54 ″ is flattened to a certain depth by the low-angle IBE, and then the end point is detected by SIMS. By flattening the insulating film 54 'until at least the upper surface of the MR laminated body 52 is exposed by low-rate IBE using, the MR laminated body 52 and the insulating film 54 around it are formed.
[0078]
When this method is used, it is possible to use a normal straight resist pattern or hard mask having no reverse taper, so that it is possible to form a finer MR laminate than when formed using the lift-off method. . In addition, since RIE, a hard mask, or the like that can reduce the occurrence of skirting when the MR laminate 52 is milled can be utilized, it can greatly contribute to the improvement of the shape of the MR laminate 52. Furthermore, the occurrence of burrs or overlaps in the insulating film 54 cannot occur, and a more strict definition of the track width is possible. Therefore, an MR element having a track width of 200 nm or less can be easily manufactured. Actually, a TMR element having good output characteristics with a track width of 100 nm could be manufactured.
[0079]
In addition, according to the present embodiment, since the end point of the MR multilayer body 52 is detected by detecting the end point by the low rate IBE and SIMS, the end point of the flattening process can be controlled very easily and accurately. can do.
[0080]
FIG. 6 is a cross-sectional view showing a partial process of forming a TMR head or a GMR head having a CPP structure as still another embodiment of the present invention.
[0081]
First, as shown in FIG. 2A, a lower electrode film 61 that also serves as a magnetic shield film and an MR multilayer film 62 ′ are sequentially stacked on an insulating film 60 formed on a substrate (not shown).
[0082]
Next, as shown in FIG. 2B, a photoresist pattern 63 having straight side walls is formed thereon.
[0083]
Next, as shown in FIG. 3C, the MR multilayer film 62 'is patterned by IBE, RIE, RIBE or sputtering using the photoresist pattern 63 as a mask, and the upper surface of the MR multilayer body becomes a junction. 62 is obtained.
[0084]
The MR multilayer 62 includes a TMR multilayer, a CPP-structured GMR multilayer, a TMR multilayer including a bias layer for defining the magnetization direction with respect to the free layer, or a CPP-structured GMR multilayer, and an antiferromagnetically coupled magnetic multilayer film. For example, a CPP structure GMR multilayer having a specular spin-valve magnetic multilayer film, or a CPP structure GMR multilayer having a dual spin-valve magnetic multilayer film.
[0085]
Next, as shown in FIG. 4D, after removing the photoresist pattern 63 as a mask, an insulating film 64 ″ having a convex junction is formed on the entire surface. The film thickness of the insulating film 64 ″ is preferably equal to or larger than the film thickness of the MR multilayer 62 in order to perform reliable insulation.
[0086]
Thereafter, as shown in FIG. 5E, a planarization process using GCIB is performed to planarize the insulating film 64 ″ until at least the upper surface (junction) of the MR multilayer 62 is exposed. Get ´.
[0087]
The planarization process using GCIB in this case is, for example, that a gas cluster is created by injecting a gas such as Ar into a high vacuum and rapidly cooling, and the clustered gas is applied to the surface of the object. The surface is flattened by bumping. The end of planarization is controlled by managing the planarization processing time.
[0088]
As an example of planarization using GCIB, the conditions are as follows.
Acceleration voltage: 15 kV
Dose amount: 1 × 10¹⁶ions / cm².
[0089]
Next, as shown in FIG.₂The insulating film 64 ′ is flattened until at least the upper surface (junction) of the MR multilayer body 62 is exposed by performing a low rate IBE with an etching rate of 2 nm / min or less). The insulating film 64 is obtained. The end of planarization may be controlled by managing the planarization processing time, but it is desirable to easily detect the end point using, for example, SIMS. Note that when endpoint detection is performed using SIMS, since the area of the MR multilayer 62 is very small, detection is facilitated by previously stacking an endpoint detection film. That is, when the insulating film 64 ″ is formed, the film is formed to the same or slightly lower height as the MR multilayer 62, and a very thin end point detection film is provided thereon, and then the insulating film 64 ″ is again formed. If film formation is performed, detection by SIMS becomes easy.
[0090]
As an example of low-rate IBE, the etching conditions are as follows:
Beam incident angle: 90 degrees
Acceleration voltage: 250V
Beam current: 0.1 mA / cm²
Ar gas pressure: 2 × 10^-4Torr
Substrate temperature: 50 ° C
Etching time: about 15 minutes.
[0091]
Thereafter, as shown in FIG. 4G, an upper electrode film 65 that also serves as a magnetic shield film is formed on the planarized insulating film 64 and MR multilayer 62.
[0092]
A hard mask may be used instead of the photoresist pattern 63. When a conductive hard mask is used, the hard mask may be left without being removed and used as a cap layer of the MR multilayer 62.
[0093]
Each film, the film thickness of each layer, the constituent materials, and the like in this embodiment are the same as those in the embodiment of FIG. 3a. The structure of the MR stack 62 is the same as that in the embodiment of FIG. 3a.
[0094]
According to this embodiment, the insulating film 64 ″ is stacked on the MR multilayer 62 and the lower electrode film 61, and the insulating film 64 ″ is planarized to a certain depth by planarization using GCIB, and thereafter, SIMS. By flattening the insulating film 64 ′ until at least the upper surface of the MR stacked body 62 is exposed by low-rate IBE using end point detection according to the above, the MR stacked body 62 and the surrounding insulating film 64 are formed.
[0095]
When this method is used, it is possible to use a normal straight resist pattern or hard mask having no reverse taper, so that it is possible to form a finer MR laminate than when formed using the lift-off method. . In addition, since RIE, a hard mask, or the like that can reduce the occurrence of skirting when milling the MR multilayer 62 can be utilized, it can greatly contribute to the improvement of the shape of the MR multilayer 62. Furthermore, the occurrence of burrs and overlaps in the insulating film 64 cannot occur, and a more strict definition of the track width is possible, so that an MR element having a track width of 200 nm or less can be easily manufactured. Actually, a TMR element having good output characteristics with a track width of 100 nm could be manufactured.
[0096]
In addition, according to the present embodiment, since the end point of the MR multilayer 62 is detected by detecting the end point by low rate IBE and SIMS, the end point of the flattening process can be controlled very easily and accurately. can do. Since the etching rate of GCIB is very slow, it is not realistic to perform planarization and cueing only with GCIB.
[0097]
FIG. 7 is a sectional view showing a partial process of forming a GMR head having a TMR head or a CPP structure as still another embodiment of the present invention.
[0098]
First, as shown in FIG. 2A, a lower electrode film 71 that also serves as a magnetic shield film and an MR multilayer film 72 ′ are sequentially stacked on an insulating film 70 formed on a substrate (not shown).
[0099]
Next, as shown in FIG. 3B, a photoresist pattern 73 having straight side walls is formed thereon.
[0100]
Next, as shown in FIG. 3C, the MR multilayer 72 ′ is patterned by IBE, RIE, RIBE or sputtering using the photoresist pattern 73 as a mask, and the upper surface of the MR multilayer is a junction. 72 is obtained.
[0101]
The MR multilayer 72 includes a TMR multilayer, a CPP-structured GMR multilayer, a TMR multilayer including a bias layer for defining the magnetization direction with respect to the free layer, or a CPP-structured GMR multilayer, and an antiferromagnetically coupled magnetic multilayer film. For example, a CPP structure GMR multilayer having a specular spin-valve magnetic multilayer film, or a CPP structure GMR multilayer having a dual spin-valve magnetic multilayer film.
[0102]
Next, as shown in FIG. 4D, after removing the photoresist pattern 73 as a mask, an insulating film 74 ″ ″ having a convex junction is formed on the entire surface. The film thickness of the insulating film 74 ″ ″ is preferably equal to or larger than the film thickness of the MR multilayer 72 in order to perform reliable insulation.
[0103]
Thereafter, as shown in FIG. 5E, the insulating film 74 ″ is flattened to some extent by performing low-angle IBE in which a beam is incident on the laminated surface at a low angle, thereby obtaining the insulating film 74 ″.
[0104]
In this case, the low angle IBE is preferably such that the angle formed between the incident ion beam and the laminated surface is 0 to 40 degrees. If the angle is larger than 40 degrees, flattening becomes difficult. The angle formed between the incident ion beam and the laminated surface is more preferably 0 to 30 degrees, and most preferably 0 to 20 degrees. The end of planarization is controlled by managing the planarization processing time.
[0105]
As an example of the low angle IBE, the etching conditions are as follows:
Beam incident angle: 20 degrees
Acceleration voltage: 300V
Beam current: 0.35 mA / cm²
Ar gas pressure: 2.4 × 10^-4Torr
Substrate temperature: 30 ° C
Etching time: about 12 minutes.
[0106]
Thereafter, as shown in FIG. 5F, a planarization process using GCIB is performed to planarize the insulating film 74 ″ until at least the upper surface (junction) of the MR multilayer 72 is exposed. Get ´.
[0107]
The planarization process using GCIB in this case is, for example, that a gas cluster is created by injecting a gas such as Ar into a high vacuum and rapidly cooling, and the clustered gas is applied to the surface of the object. The surface is flattened by bumping. The end of planarization is controlled by managing the planarization processing time.
[0108]
As an example of planarization using GCIB, the conditions are as follows.
Acceleration voltage: 15 kV
Dose amount: 1 × 10¹⁶ions / cm².
[0109]
Next, as shown in FIG.₂The insulating film 74 ′ is flattened until at least the upper surface (junction) of the MR multilayer body 72 is exposed by performing a low rate IBE with an etching rate of 2 nm / min or less). The insulating film 74 is obtained. The end of planarization may be controlled by managing the planarization processing time, but it is desirable to easily detect the end point using, for example, SIMS. When endpoint detection is performed using SIMS, since the area of the MR multilayer 72 is very small, detection is facilitated by previously stacking an endpoint detection film. That is, when forming the insulating film 74 ″ ″, the film is formed to the same or slightly lower height as the MR multilayer 72, and a very thin end point detection film is provided thereon, and then the insulating film 74 ″ is again formed. If 'is deposited, detection by SIMS becomes easy.
[0110]
As an example of low-rate IBE, the etching conditions are as follows:
Beam incident angle: 90 degrees
Acceleration voltage: 250V
Beam current: 0.1 mA / cm²
Ar gas pressure: 2 × 10^-4Torr
Substrate temperature: 50 ° C
Etching time: about 15 minutes.
[0111]
Thereafter, as shown in FIG. 6H, an upper electrode film 75 that also serves as a magnetic shield film is formed on the planarized insulating film 74 and MR multilayer 72.
[0112]
A hard mask may be used instead of the photoresist pattern 73. When a conductive hard mask is used, the hard mask may be left without being removed and used as a cap layer of the MR multilayer 72.
[0113]
Each film, the film thickness of each layer, the constituent materials, and the like in this embodiment are the same as those in the embodiment of FIG. 3a. Also, the structure of the MR stack 72 is the same as in the embodiment of FIG. 3a.
[0114]
According to the present embodiment, the insulating film 74 ″ ″ is stacked on the MR multilayer 72 and the lower electrode film 71, and the insulating film 74 ″ is made to a certain depth by flattening using low angle IBE and GCIB. The insulating film 74 ′ is flattened until the at least upper surface of the MR stacked body 72 is exposed by low-rate IBE using end point detection by SIMS, so that the MR stacked body 72 and the insulating film 74 around it are formed. Is forming.
[0115]
When this method is used, it is possible to use a normal straight resist pattern or hard mask having no reverse taper, so that it is possible to form a finer MR laminate than when formed using the lift-off method. . In addition, since RIE, a hard mask, or the like that can reduce the occurrence of skirting when the MR laminate 72 is milled can be utilized, it can greatly contribute to the improvement of the shape of the MR laminate 72. Furthermore, the occurrence of burrs, overlaps, etc. in the insulating film 74 cannot occur, and a stricter track width can be defined. Therefore, an MR element having a track width of 200 nm or less can be easily manufactured. Actually, a TMR element having good output characteristics with a track width of 100 nm could be manufactured.
[0116]
In addition, according to this embodiment, the end point of the MR multilayer body 72 is detected by performing end point detection by low-rate IBE and SIMS, so that the end point of the flattening process can be controlled very easily and accurately. can do. Since the etching rate of GCIB is very slow, it is not realistic to perform planarization and cueing only with GCIB.
[0117]
FIG. 8 is a cross-sectional view showing a partial process of forming a TMR head or a GMR head having a CPP structure as still another embodiment of the present invention.
[0118]
First, as shown in FIG. 2A, a lower electrode film 81 that also serves as a magnetic shield film and an MR multilayer film 82 'are sequentially stacked on an insulating film 80 formed on a substrate (not shown).
[0119]
Next, as shown in FIG. 2B, a photoresist pattern 83 having straight side walls is formed thereon.
[0120]
Next, as shown in FIG. 3C, the MR multilayer film 82 'is patterned by IBE, RIE, RIBE or sputtering using the photoresist pattern 83 as a mask, and the MR multilayer body whose upper surface becomes a junction. Get 82.
[0121]
The MR multilayer 82 includes a TMR multilayer, a CPP-structured GMR multilayer, a TMR multilayer including a bias layer for defining the magnetization direction with respect to the free layer, or a CPP-structured GMR multilayer, and an antiferromagnetically coupled magnetic multilayer film. For example, a CPP structure GMR multilayer having a specular spin valve magnetic multilayer film, or a CPP structure GMR multilayer having a dual spin valve magnetic multilayer film.
[0122]
Next, as shown in FIG. 4D, after removing the photoresist pattern 83 which is a mask, an insulating film 84 ′ having a convex junction is formed on the entire surface. The film thickness of the insulating film 84 ′ is desirably equal to or greater than the film thickness of the MR multilayer 82 in order to perform reliable insulation.
[0123]
Thereafter, as shown in FIG. 5E, the precision CMP is performed to flatten the insulating film 84 ′ until at least the upper surface (junction) of the MR multilayer 82 is exposed, that is, the MR multilayer 82 is cued. Then, an insulating film 84 is obtained.
[0124]
The precise CMP in this case is a precise CMP process that is controlled more precisely than a normal CMP process. In the precision CMP process, the polishing rate is low at a polishing rate of 50 nm / min or less, preferably 20 nm / min or less, more preferably 10 nm / min or less and low residual level dry or low in order to enable precise control. Wet CMP. When the polishing rate exceeds 50 nm / min, high-precision control becomes difficult.
[0125]
Therefore, colloidal silica, cerium oxide, corundum, boron nitride, diamond, chromium oxide, iron oxide, fumed silica, alumina, and a mixture containing one kind of zeolite, an average particle diameter of 100 nm or less, Preferably, a slurry of 50 nm or less, more preferably 10 nm or less is used. When the average particle size of the slurry exceeds 100 nm, it becomes difficult to control with high accuracy. The rotation speed of the plate is 1 rpm to 10000 rpm. When this rotational speed is less than 1 rpm, the polishing speed becomes too slow and the productivity is deteriorated. In addition, when the rotational speed exceeds 10,000 rpm, high-precision control becomes difficult.
[0126]
The planarization is completed by managing the planarization processing time.
[0127]
Thereafter, as shown in FIG. 5F, an upper electrode film 85 that also serves as a magnetic shield film is formed on the planarized insulating film 84 and MR multilayer 82.
[0128]
A hard mask may be used instead of the photoresist pattern 83. When a conductive hard mask is used, the hard mask may be left without being removed and used as a cap layer of the MR multilayer 82.
[0129]
Each film, the film thickness of each layer, the constituent materials, and the like in this embodiment are the same as those in the embodiment of FIG. 3a. Also, the structure of the MR stack 82 is the same as in the embodiment of FIG. 3a.
[0130]
According to the present embodiment, the insulating film 84 ′ is stacked on the MR multilayer 82 and the lower electrode film 81, and the insulating film 84 ′ is flattened until at least the upper surface of the MR multilayer 82 is exposed by planarization by precision CMP. Thus, the MR laminated body 82 and the insulating film 84 around it are formed.
[0131]
When this method is used, it is possible to use a normal straight resist pattern or hard mask having no reverse taper, so that it is possible to form a finer MR laminate than when formed using the lift-off method. . In addition, since RIE, a hard mask, or the like that can reduce the occurrence of skirting when the MR laminate 82 is milled can be utilized, it can greatly contribute to the improvement of the shape of the MR laminate 82. Furthermore, the occurrence of burrs, overlaps, etc. in the insulating film 84 cannot occur, and the stricter track width can be defined, so that an MR element having a track width of 200 nm or less can be easily manufactured. Actually, a TMR element having good output characteristics with a track width of 100 nm could be manufactured.
[0132]
Further, after forming the insulating film 84 ', a recess is formed around the MR multilayer 82, and the magnetic field passing through the upper electrode film entering the MR multilayer 82 enters the MR multilayer 82, which is a cause of deteriorating MR characteristics. According to this embodiment, since the recess is eliminated by using CMP, an improvement in MR characteristics can be expected.
[0133]
FIG. 9 is a sectional view showing a partial process of forming a TMR head or a GMR head having a CPP structure as still another embodiment of the present invention.
[0134]
First, as shown in FIG. 2A, a lower electrode film 91 that also serves as a magnetic shield film and an MR multilayer film 92 ′ are sequentially stacked on an insulating film 90 formed on a substrate (not shown).
[0135]
Next, as shown in FIG. 2B, a photoresist pattern 93 having straight sidewalls is formed thereon.
[0136]
Next, as shown in FIG. 3C, the MR multilayer 92 ′ is patterned by IBE, RIE, RIBE or sputtering using the photoresist pattern 93 as a mask, and the upper surface of the MR multilayer is a junction. 92 is obtained.
[0137]
The MR multilayer 92 includes a TMR multilayer, a CPP-structured GMR multilayer, a TMR multilayer including a bias layer for defining the magnetization direction with respect to the free layer, or a CPP-structured GMR multilayer, and an antiferromagnetically coupled magnetic multilayer film. For example, a CPP structure GMR multilayer having a specular spin valve magnetic multilayer film, or a CPP structure GMR multilayer having a dual spin valve magnetic multilayer film.
[0138]
Next, as shown in FIG. 4D, after removing the photoresist pattern 93 as a mask, an insulating film 94 ″ having a convex junction is formed on the entire surface. The film thickness of the insulating film 94 ″ is desirably equal to or larger than the film thickness of the MR multilayer body 92 in order to perform reliable insulation.
[0139]
Next, as shown in FIG. 5E, a photoresist pattern 96 having an opening 96a corresponding to the contact hole is formed on the insulating film 94 ″.
[0140]
Next, as shown in FIG. 6F, ion milling of the insulating film 94 ″ is performed using the photoresist pattern 96 as a mask, and the insulating film 94 ′ having a contact hole 94a ′ on the MR multilayer 92 is formed. Then, the photoresist pattern 96 is peeled off.
[0141]
Thereafter, as shown in FIG. 5G, the precision CMP is performed to flatten the insulating film 94 'until at least the upper surface (junction) of the MR multilayer body 92 is exposed, that is, to cue the MR multilayer body 92. An insulating film 94 is obtained.
[0142]
The precise CMP in this case is a precise CMP process that is controlled more precisely than a normal CMP process. In the precision CMP process, the polishing rate is low at a polishing rate of 50 nm / min or less, preferably 20 nm / min or less, more preferably 10 nm / min or less and low residual level dry or low in order to enable precise control. Wet CMP. When the polishing rate exceeds 50 nm / min, high-precision control becomes difficult.
[0143]
Therefore, colloidal silica, cerium oxide, corundum, boron nitride, diamond, chromium oxide, iron oxide, fumed silica, alumina, and a mixture containing one kind of zeolite, an average particle diameter of 100 nm or less, Preferably, a slurry of 50 nm or less, more preferably 10 nm or less is used. When the average particle size of the slurry exceeds 100 nm, it becomes difficult to control with high accuracy. The rotation speed of the plate is 1 rpm to 10000 rpm. When this rotational speed is less than 1 rpm, the polishing speed becomes too slow and the productivity is deteriorated. In addition, when the rotational speed exceeds 10,000 rpm, high-precision control becomes difficult.
[0144]
The planarization is completed by managing the planarization processing time.
[0145]
Thereafter, as shown in FIG. 5H, an upper electrode film 95 that also serves as a magnetic shield film is formed on the planarized insulating film 94 and MR multilayer body 92.
[0146]
A hard mask may be used in place of the photoresist pattern 93. When a conductive hard mask is used, the hard mask may be left without being removed and used as a cap layer of the MR multilayer 92.
[0147]
Each film, the film thickness of each layer, the constituent materials, and the like in this embodiment are the same as those in the embodiment of FIG. 3a. The structure of the MR stack 92 is the same as that in the embodiment of FIG. 3a.
[0148]
According to the present embodiment, the insulating film 94 ″ is stacked on the MR stacked body 92 and the lower electrode film 91, contact holes are formed on the insulating film 94 ″, and then the MR stacked body is planarized by precision CMP. By planarizing the insulating film 94 ′ until at least the upper surface of 82 is exposed, the MR stack 92 and the insulating film 94 around it are formed.
[0149]
When this method is used, it is possible to use a normal straight resist pattern or hard mask having no reverse taper, so that it is possible to form a finer MR laminate than when formed using the lift-off method. . In addition, since RIE, a hard mask, or the like that can reduce the occurrence of skirting when milling the MR multilayer 92 can be used, it can greatly contribute to the improvement of the shape of the MR multilayer 92. Furthermore, the occurrence of burrs and overlaps in the insulating film 94 cannot occur, and a more strict definition of the track width is possible, so that an MR element having a track width of 200 nm or less can be easily manufactured. Actually, a TMR element having good output characteristics with a track width of 100 nm could be manufactured.
[0150]
Further, after forming the insulating film 94 ', a recess is formed around the MR multilayer 92, and a magnetic field passing through the upper electrode film entering the MR multilayer 92 enters the MR multilayer 92, which is a cause of deteriorating MR characteristics. According to this embodiment, since the recess is eliminated by using CMP, an improvement in MR characteristics can be expected.
[0151]
In general, when the convex portions of the insulating film polished by CMP are of different sizes, the polishing conditions become more severe, and the dishing or insulating film in which the insulating film in the concave portion becomes concave rather than flat is thin. Cause the occurrence of thinning. In order to prevent this, photo milling is performed in such a manner that the center of the convex portion is extracted in different sizes by contact holes of different diameters. As a result, since the size of the convex portion after milling is standardized, it is possible to earn a margin for CMP polishing conditions.
[0152]
This embodiment undergoes a process similar to that of the so-called contact hole method, but there is a great difference in that the insulating film overlapping the upper surface of the MR multilayer 92 is completely removed by polishing with CMP. .
[0153]
All the embodiments described above are illustrative of the present invention and are not intended to be limiting, and the present invention can be implemented in other various modifications and changes. Therefore, the scope of the present invention is defined only by the claims and their equivalents.
[0154]
【The invention's effect】
  As described above in detail, according to the present invention, an insulating film is laminated on the MR laminated body and the lower electrode film instead of the lift-off method, and the insulating film laminated until at least the upper surface of the MR laminated body is exposed.By processing with GCIB and low rate IBE with low etching rateBy planarizing, the MR laminated body and the insulating film around it are formed.
[0155]
When this method is used, it is possible to use a normal straight resist pattern having no reverse taper, so that it is possible to form a finer MR laminate than when formed using the lift-off method. In addition, since RIE, a hard mask, and the like that can reduce the occurrence of skirting when milling the MR laminate can be utilized, it is possible to greatly contribute to the improvement of the shape of the MR laminate. Furthermore, the occurrence of burrs and overlaps in the insulating film cannot occur, and the stricter definition of the track width is possible. Therefore, an MR element in which the track width is 200 nm or less and a current flows in a direction perpendicular to the laminated surface can be easily obtained. Can be manufactured.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a partial process for forming a GMR head having a CPP structure by a lift-off method.
FIG. 2 is a sectional view showing a partial process of forming a GMR head having a CPP structure by a contact hole method.
FIG. 3a is a cross-sectional view showing a partial process of forming a TMR head or a GMR head having a CPP structure as an embodiment of the present invention.
3b is a cross-sectional view showing in more detail the actual planarization process in the embodiment of FIG. 3a.
4a is a cross-sectional view schematically illustrating an example of a layer structure of a TMR head formed according to the embodiment of FIG. 3a.
4b is a cross-sectional view schematically illustrating another example of a layer structure of a TMR head formed according to the embodiment of FIG. 3a.
FIG. 5 is a cross-sectional view showing a partial process of forming a TMR head or a GMR head having a CPP structure as another embodiment of the present invention.
FIG. 6 is a cross-sectional view showing a partial process of forming a TMR head or a GMR head having a CPP structure as still another embodiment of the present invention.
FIG. 7 is a cross-sectional view showing a partial process of forming a GMR head having a TMR head or a CPP structure as still another embodiment of the present invention.
FIG. 8 is a cross-sectional view showing a partial process of forming a GMR head having a TMR head or a CPP structure as still another embodiment of the present invention.
FIG. 9 is a cross-sectional view showing a partial process of forming a TMR head or a GMR head having a CPP structure as still another embodiment of the present invention.
[Explanation of symbols]
10, 14, 14 ′, 20, 24, 24 ′, 30, 34, 34 ′, 50, 54, 54 ′, 54 ″, 60, 64, 64 ′, 64 ″, 70, 74, 74 ′, 74 ″, 80, 84, 84 ′, 90, 94, 94 ′, 94 ″ insulating film
11, 21, 31, 51, 61, 71, 81, 91 Lower electrode film
12, 22, 32, 52, 62, 72, 82, 92 MR multilayer
12 ', 22', 32 ', 52', 62 ', 72', 82 ', 92' MR multilayer film
13, 23, 26, 33, 53, 63, 73, 83, 93, 96 Photoresist pattern
13a base
15, 25, 35, 55, 65, 75, 85, 95 Upper electrode film
24a, 94a Contact hole
26a, 96a opening
32a Underlayer
32b pinned layer
32c pinned layer
32d tunnel barrier layer
32e free layer
32f cap layer
32g nonmagnetic metal layer
32h antiferromagnetic layer

Claims (12)

On the lower electrode film, a magnetoresistive effect layered body in which a current flows in a direction perpendicular to the laminated surface is formed, an insulating film is laminated on the formed magnetoresistive effected layered body and the lower electrode film, and the laminated insulation The film is planarized using a gas cluster ion beam until at least the upper surface of the magnetoresistive stack is exposed, and the planarized insulating film is 2 nm / until at least the upper surface of the magnetoresistive stack is exposed. min following were thus flattened low rate ion beam etch in g of low etching rate, having a magnetoresistive element and forming an upper electrode film on the planarized insulating layer and the magnetoresistive stack on Manufacturing method of thin film magnetic head.   By laminating a magnetoresistive multilayer film on the lower electrode film, forming a mask on the laminated magnetoresistive multilayer film, patterning the magnetoresistive multilayer film, and removing the mask The manufacturing method according to claim 1, wherein a magnetoresistive laminate is formed.   A magnetoresistive multilayer film is laminated on the lower electrode film, a mask is formed on the laminated magnetoresistive multilayer film, and the magnetoresistive multilayer film is patterned. The manufacturing method according to claim 1, wherein the magnetoresistive laminate is formed by using as a cap layer. The flattening further method according to any one of claims 1 to 3 in which the beam at low angles with respect to the laminated surface and performing by the a low-angle ion beam etching incident. The manufacturing method according to claim 4, wherein an angle formed between the incident beam and the laminated surface in the low-angle ion beam etching is 0 to 40 degrees. The method according to claim 1, any one of 5, characterized in that said flattening, and exit managing a flattening process time. The method according to any one of claims 1 to 5, characterized in that ends by the flattening, for endpoint detection. The manufacturing method according to claim 7 , wherein the end point detection is performed using a secondary ion mass spectrometer. The magnetoresistive stack, The method according to any one of claims 1 8, characterized in that a tunneling magnetoresistive stack. The magnetoresistive stack, The method according to any one of claims 1 8, characterized in that the vertical current passing through giant magnetoresistive stack. The magnetoresistive stack method according to any one of claims 1 to 8, characterized in that a tunneling magnetoresistive stack including a bias layer for defining the magnetization direction with respect to the free layer. The magnetoresistive stack, to any one of claims 1 to 8, characterized in that the vertical current passing through giant magnetoresistive stack including a bias layer for defining the magnetization direction with respect to the free layer The manufacturing method as described.

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