JP2002150513A - Lift-off mask pattern forming method, magnetic element using the same, and method of manufacturing thin-film magnetic head - Google Patents

Abstract

(57) Abstract: A lift-off mask pattern forming method which is easier to control a mask pattern shape than a conventional lift-off mask formed by a two-layer resist method, can be formed with a small number of lithography steps, and is easy to peel off. And a method of manufacturing a magnetic element and a thin-film magnetic head using the same. Kind Code: A1 Abstract: In a recording / reproducing separation type thin-film magnetic head using a magnetoresistive element as a reproducing element or a magnetic element having at least one magnetic separating film, a multilayer film made of a magnetic material and a nonmagnetic material is used. In forming a lift-off mask pattern used for processing, the positive-type radiation-sensitive material is exposed and then developed with a non-polar organic solvent to leave a portion exposed to form a negative-type pattern, thereby forming a lift-off mask.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film magnetic head used for recording / reproducing of a magnetic disk device and the like, and a method of manufacturing the same. Further, the present invention relates to a magnetic element represented by a magnetic random access memory (MRAM) and the like, a magnetic micro element represented by a thin film inductor and the like, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Currently, a magnetic disk drive used for recording and reproducing information of a computer or the like mainly includes a recording / reproducing separation type head in which recording is performed by an inductive thin film head and reproduction is performed by a magnetoresistive head. It is used for At present, GMR heads utilizing a giant magnetoresistance effect are mainly used as reproducing heads.

FIG. 1 shows the structure of a typical giant magnetoresistive head for reproduction (GMR head) as viewed from the flying surface of the head (the surface facing the magnetic disk). As shown in FIG. 1, the magnetoresistive effect element constituting the GMR head includes a magnetoresistive effect film 1, a magnetic domain control film 2, and an electrode film 3, and is provided above and below the element to block unnecessary magnetic fields. Shielding layers 4 and 5, and insulating film 6 for insulating between the element and the shield
And 7 exist.

The above giant magnetoresistive head (GMR head)
FIG. 2 shows a method of forming the head. As shown in FIG. 2A, a lower insulating film 6 is formed on a flat lower shield layer 4, and a multilayer film made of a magnetic material and a non-magnetic material to be the magnetoresistive film 1 is formed by a sputtering method or the like. The layers are stacked, and a lift-off mask 8 is formed thereon by photolithography or the like. After that, as shown in FIG. 2 (2), after the area not covered by the mask is cut by ion milling or the like,
As shown in FIG. 2C, a magnetic domain control film 2 and an electrode film 3 are deposited in a predetermined shape on a part of the cut region by a sputtering method or the like. Remove the lift-off mask (Fig. 2
(4)) By forming the upper insulating film 7 and the upper shield layer 5 thereon (FIG. 2 (5)), a GMR element can be produced.

As a method of forming a lift-off mask used in this process, there are two types, a single-layer resist method and a multilayer resist method. Representative 2 among multilayer resist methods
In the layer resist method, as disclosed in JP-A-2-17643, a lift-off mask is formed as follows. After applying and baking an aqueous alkali developable resist as a lower layer resist on the multilayer film to be cut,
An upper resist that does not mix with the lower resist is applied. As the upper layer resist, a photosensitive i-line positive resist or a positive chemical amplification resist for KrF is often used. When a predetermined mask pattern is exposed and developed by the lithography process, the unexposed portion of the upper positive resist layer is dissolved in the aqueous alkaline developer, and then the developer penetrates to the unexposed portion of the lower resist layer. As shown in FIG. 3A, an undercut type lift-off mask in which a portion close to the substrate is more developed is obtained.

For forming a lift-off mask, a photosensitive positive resist as disclosed in JP-A-4-46346 or JP-A-61-136226 is used.
As described in U.S. Pat. No. 6,086,867, a single-layer resist method using only a negative resist is actually used. When a single-layer resist is used, the cross-sectional shape of the obtained lift-off mask pattern varies depending on the optical characteristics of the resist, the solubility characteristics in the developing solution, and the polarity of the developing solution. As shown in FIG. Various cross-sectional shapes such as a mold, (2) a reverse taper type (reverse trapezoid type), and (3) a rectangle can be obtained.

In the prior art, an undercut type or a reverse taper type is often used as a cross-sectional shape of a lift-off mask pattern. The reason for this is that in the step of peeling the lift-off mask after laminating the magnetic domain control film and the electrode film by sputtering or the like, the cross-sectional shape of the lift-off mask pattern has an undercut type, a reverse tapered type, and the bottom of the pattern is higher than the top of the pattern. This is because, if the width is too small, the stripping solution easily infiltrates the bottom of the resist, and the lift-off mask is easily stripped. However, in such cases,
When the magnetic domain control film and the electrode film are formed by the sputtering method, the magnetic material and the non-magnetic material forming the magnetic domain control film and the electrode film enter the bottom of the lift-off mask. As a result, the shape of the magnetoresistive element after the lift-off mask is peeled off has a so-called overhang structure in which the magnetic domain control film and the electrode film overlap the upper end of the magnetoresistive effect film. When the cross-sectional shape of the lift-off mask pattern is rectangular, the above-described overhang structure is unlikely to occur. On the other hand, the lift-off mask formed by the single-layer resist method is considered to be more difficult to remove than the lift-off mask made of a two-layer resist having an undercut shape or an inverted taper shape, because the stripping solution does not easily permeate the bottom of the resist.

[0008]

When a lift-off mask is formed using a conventional two-layer resist method, a magnetic domain is formed at the bottom of the lift-off mask regardless of whether the mask pattern is an undercut type or a reverse taper type. An overhang shape is generated in which the magnetic material and the non-magnetic material constituting the control film and the electrode film enter. If the amount of undercut or the degree of reverse taper is large, the amount of overhang of the magnetic material and the nonmagnetic material constituting the magnetic domain control film and the electrode film increases, and the magnetic domain control failure of the magnetoresistive effect element is likely to occur. Output stability becomes poor. When the amount of undercut or the degree of reverse taper is small, the overhang amount of the magnetic domain control film and the electrode film is small, but the peeling of the mask pattern becomes difficult. As described above, the shape of the lift-off mask pattern greatly affects the end shape of the magneto-resistance effect film, the magnetic domain control film, and the electrode film in the magneto-resistance effect element, but when the lift-off mask is formed by the two-layer resist method. Since the cross-sectional shape of the lift-off mask pattern changes depending on the thickness of the lower resist and the thickness of the upper photosensitive resist, it is difficult to control the shape of the lift-off mask pattern. Further, in the two-layer resist method, mixing between resists at the resist interface between the upper layer and the lower layer is inevitable, so that it is more difficult to control the pattern shape. Further, from the viewpoint of manufacturing cost reduction, it is required to reduce the number of lift-off mask formation steps. However, when a conventional two-layer resist method is used to form a lift-off mask, it is necessary to apply two resist layers. The problem is that the process becomes very complicated and the number of lithography steps increases.

On the other hand, in the case of a lift-off mask formed by using the conventional i-line single-layer positive resist method, since the cross-sectional shape of the mask pattern is rectangular, a magnetic domain control film and an electrode film are laminated by sputtering or the like. During this process, the metal material constituting these films does not enter the bottom of the lift-off mask, but tends to adhere to the side surfaces of the lift-off mask pattern.
For this reason, the stripping solution does not easily permeate the bottom of the resist, making it difficult to strip the lift-off mask. Further, there is also a problem that the above-described side surface deposit grows and a protrusion is likely to be formed near the interface between the electrode film and the upper portion of the GMR element after the lift-off mask is removed.

Accordingly, an object of the present invention is to form a lift-off mask pattern which is easier to control the mask pattern shape than the conventional lift-off mask formed by the two-layer resist method, can be formed easily with a small number of lithography steps, and is easily peeled. An object of the present invention is to provide a method, a magnetic element using the same, and a method of manufacturing a thin-film magnetic head.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a recording / reproducing separation type thin film magnetic head using a magnetoresistive element as a reproducing element or a magnetic element having at least one magnetic separation film. After cutting a multilayer film made of a non-magnetic material into a predetermined shape, a lift-off mask pattern used for laminating a magnetic material or a non-magnetic material at a predetermined position is formed on a predetermined substrate. A step of spin-coating a pattern-forming material made of a positive radiation-sensitive material on a multilayer film made of a magnetic material and a non-magnetic material to form a coating film, and a pre-bake step for removing a coating solvent, Irradiating the coating film with actinic radiation to form a predetermined pattern latent image, and baking after irradiation, and developing with a non-polar organic solvent to leave exposed portions. It can be achieved by using a lift-off mask pattern forming method characterized by comprising the step of forming a gas-type pattern.

A chemically amplified positive resist can be used as a pattern-forming material made of the above-mentioned positive radiation-sensitive material. As the base resin of the chemically amplified positive resist, a resin represented by the general formula (1) can be used.

[0013]

Embedded image

(Wherein, R1 and R2 are an aliphatic functional group such as a hydrogen atom, an alkyl group or an alkoxy group, or an aromatic functional group such as a phenyl group. R1 and R2 are the same or different. M and n are positive integers.) Further, as a base resin of a chemically amplified positive resist,
It is also possible to use a resin represented by the general formula (2).

[0015]

Embedded image

(Wherein R3 and R4 are an aliphatic functional group such as a hydrogen atom, an alkyl group or an alkoxy group, or an aromatic functional group such as a phenyl group. R3 and R4 are the same or different. Further, m and n are positive integers.) When a chemically amplified positive resist is used as a pattern-forming material made of the above-mentioned positive radiation-sensitive material, active chemical is used as a material constituting the resist. A compound that generates an acid by a line is essential. Examples of the compound that generates an acid upon irradiation with actinic radiation include various diazonium salts, various onium salts, esters of a compound having a plurality of phenolic hydroxyl groups with alkylsulfonic acid, and various halogen compounds. Examples of the counter anion of the salt in the present invention include Lewis acids such as tetrafluoroboric acid, hexafluoroantimonic acid, trifluoromethanesulfonic acid, trifluoroacetic acid, and toluenesulfonic acid. It is also possible to use compounds other than those described above that generate an acid upon irradiation with active actinic radiation.

As a method of obtaining a lift-off mask by a photolithography process using a chemically amplified positive resist as a pattern forming material made of a positive radiation-sensitive material, a manufacturing method comprising the following steps can be used. On the film formed on the substrate or the film patterned in a predetermined shape, after the solution of the above-mentioned positive pattern forming material is dropped and spin-coated, pre-baking is performed to remove the coating solvent, and the obtained is obtained. The coated film is irradiated with active actinic radiation to form a predetermined pattern latent image, and is baked after irradiation. At this time, the pre-bake temperature is preferably between 70 and 120 degrees, and the post-irradiation bake temperature is preferably between 70 and 130 degrees. Next, by developing using a non-polar organic solvent, the exposed portion is not dissolved in the non-polar organic solvent but the unexposed portion is dissolved in spite of the positive pattern forming material,
A lift-off mask pattern in which the negative and positive images are inverted can be obtained.

A feature of the chemically amplified resist is that it always contains a compound (acid generator) that generates an acid upon irradiation with actinic radiation. The acid generated in the exposed area by irradiation with actinic radiation deprotects the aqueous alkali-soluble portion of the base resin of the chemically amplified resist protected with various functional groups, and regenerates the hydroxyl group. Alternatively, it reacts with a dissolution inhibitor inhibiting the aqueous alkali solubility of the base resin to change the structure thereof, thereby acting to increase the aqueous alkali solubility of the base resin.

The acid generated by irradiation with actinic radiation is
Thus, it acts as a catalyst, and has a very high chemical activity and is easily deactivated. The deactivation of the acid depends on the underlying film. If the underlying film of the resist film is an oxide-based underlying film such as SiO2 or Al2O3, the acid does not react so much with the underlying film. Is a rectangle (rectangle). On the other hand, when the base of the resist film is a magnetic material or a non-magnetic material containing a metal element as a main component, the acid reacts with these, so that the acid contained in the resist bottom in the exposed region reacts with the base film. Will be deactivated. As a result, the latent image formed in the resist portion of the exposure area is
As shown in FIG. 4A, the tapered shape is naturally inverted. When the developing process is performed using an aqueous alkaline developer mainly containing an ordinary aqueous solution of tetramethylammonium hydroxide as it is, the resulting resist has a cross-sectional shape of FIG.
As shown in (2), the bottom of the resist is gently spread to form a skirt. On the other hand, when a non-polar organic solvent is used as a developing solution, the resist in the exposed portion does not dissolve because of the action of the acid and becomes aqueous alkali-soluble, and the resist in the unexposed portion dissolves. Is obtained. The pattern obtained at this time is close to the latent image formed by exposure, and has an inverted trapezoidal shape (inverted tapered type) as shown in FIG. In this way, by using the negative-positive reversal image method in which the positive-type chemically amplified resist is developed with an organic solvent after exposure, it is possible to obtain a lift-off mask having a reverse tapered cross-sectional shape that can be easily separated by a simple lithography process. It becomes possible.

As described above, the degree of the reverse taper at the bottom of the lift-off mask affects the overhang amount of the magnetic domain control film and the electrode film in contact with the end of the magnetoresistive film. Also, if the cross-sectional shape of the lift-off mask is a simple rectangle,
Removal of the lift-off mask becomes difficult. For this reason, an ideal lift-off mask is required to have a shape that minimizes the amount of overhang of the magnetic domain control film and the electrode film and is easy to peel off. In order to obtain an optimal lift-off mask pattern shape, the amount of acid deactivation generated during exposure may be controlled. As this method, first, selection of a base film can be considered. Even if the same exposure amount is given using the same resist material, if the underlying film is different, the amount of reaction between the underlying film and the acid generated by exposure is different, so that the tapered shape at the bottom of the resist pattern is different. It is possible to control the shape of the lift-off mask pattern by examining various underlayers and selecting an underlayer that gives an optimal taper shape. NiFe alloys of various compositions including Ta, W, Ru, Cu, Au, Permalloy and NiFeCr alloys of various compositions can be used as the base film used at this time. It is also possible to use a base film having a composition other than the above.

As a method of controlling an optimum lift-off mask pattern shape, there is a method of controlling the composition of a chemically amplified positive resist material. Basic positive-type chemically amplified resist consists of a base resin, a dissolution inhibitor (some of the base resin structure may have dissolution inhibiting properties), a photoacid generator, and various additives dissolved in an organic solvent. It was done. Various additives are used to 1) improve the stability over time of the resist solution, 2) improve the compatibility of the resist solution, 3) improve the developing performance, and 4) optimize the diffusion of acid generated by light.
Used for etc. Therefore, it is possible to optimize the shape of the lift-off mask pattern by controlling the amount of the additive used for the fourth application (optimizing the diffusion of the acid generated by light).

According to the method described above, the height of the reverse taper type at the height of 1 μm or less and the bottom of the pattern, which is optimal for fine processing of the GMR head having the reproduction track width of 0.1 to 0.5 μm. Can be obtained in the range of 10 nm to 100 nm.

The active actinic radiation to be irradiated when forming the lift-off pattern includes electron beams, X-rays, ultraviolet rays, and far ultraviolet rays. KrF having a wavelength of 248 nm as a light source for ultraviolet rays
Excimer laser is mentioned. As the far ultraviolet light having a wavelength of 200 nm or less, a deuterium lamp, SOR light, an ArF excimer laser having a wavelength of 193 nm, or the like can be used as a light source. It is also possible to use other vacuum ultraviolet light sources.

As the non-polar organic solvent used for development after irradiation with actinic radiation, a non-polar organic solvent such as a mixed solvent of methylene chloride and hexane can be used. Use of non-polar organic solvents other than those described above is also possible.

A positive type chemically amplified resist is used at a wavelength of 248 n.
It is also possible to use a positive-type chemically amplified resist for KrF excimer laser lithography of m or a positive-type chemically amplified resist for ArF excimer laser lithography with a wavelength of 193 nm.

Alternatively, the positive type chemically amplified resist can be used as a positive type chemically amplified resist for electron beam lithography.

The cross-sectional shape of the lift-off mask pattern formed of the positive type chemically amplified resist when cut perpendicular to the substrate is rectangular at the top of the pattern and inverted trapezoidal at the bottom of the pattern near the substrate surface. . Further, it is preferable that the height of the lift-off mask pattern is 1 μm or less and the height of the inverted trapezoid at the bottom of the pattern is in the range of 10 nm to 100 nm.

Further, far-ultraviolet light having a wavelength of 250 nm or less is used as active actinic radiation for irradiating a coating film made of a pattern-forming material. Alternatively, KrF excimer laser light having a wavelength of 248 nm is used as an active actinic ray for irradiating a coating film made of a pattern forming material. Alternatively, ArF excimer laser light having a wavelength of 193 nm is used as active actinic radiation for irradiating a coating film made of a pattern forming material. Alternatively, an electron beam is used as an active actinic ray for irradiating a coating film made of a pattern forming material.

[0029]

Next, the present invention will be described in more detail, but the present invention is not limited to these examples.

Example 1 Resin represented by general formula (3)

[0031]

Embedded image

(Wherein R5 and R6 are an aliphatic functional group such as a hydrogen atom, an alkyl group or an alkoxy group, or an aromatic functional group such as a phenyl group. R5 and R6 are the same or different. And m and n are positive integers.): 100 parts by weight and triphenylsulfonium triflate as a compound capable of generating an acid with respect to actinic radiation are mixed in an organic solvent at a ratio of 5 parts by weight. Thus, a solution of a positive type chemically amplified resist material having a solid content of about 12% by weight was obtained.

In the reproducing head manufacturing process of the recording / reproducing separation type head, NiF is deposited on an alumina titanium carbide substrate.
A lower shield film made of e-alloy, sendust or soft magnetic amorphous alloy was formed. A lower gap film made of Al2O3, SiO2, or a mixed film thereof is formed on the lower shield film j by sputtering or CV.
Formed by Method D. On this lower gap film, a multilayer film serving as a magnetoresistive film was laminated by a sputtering method or an ion beam sputtering method.

Next, a chemically amplified positive resist solution having the above-described composition is dropped on the multilayer film laminated on the substrate, spin-coated, and prebaked at 80 ° C. for 5 minutes to form a film having a thickness of 400 μm.
nm was obtained. A KrF having a wavelength of 248 nm is provided on this substrate.
Exposure 30mJ / c with excimer laser beam through mask
Irradiated at m2 and heat treated at 80 ° C. for 5 minutes. Next, the substrate was developed using a non-polar organic solvent composed of a mixed solvent of methylene chloride and hexane, and rinsed with pure water. In this developing method, the resist in the unexposed portion is dissolved in the non-polar organic solvent and the resist in the exposed portion remains, so that a pattern in which the negative and positive images are inverted is obtained. When the pattern arrangement on the exposure mask used in the lithography process was such that the portion left as the lift-off mask was the exposed portion, a good lift-off mask pattern having a reverse tapered cross section as shown in FIG. 3 was obtained. At this time, the height of the obtained lift-off mask pattern was 380 nm, and the height of the tapered portion was 3
It was 0 nm. As a result, a lift-off mask pattern could be formed on the multilayer film having the magnetoresistive effect of the reproducing head by using a process simpler than the conventional method.

(Example 2) Instead of the resin used in Example 1, a resin represented by the general formula (4)

[0036]

Embedded image

(Wherein R7 and R8 are an aliphatic functional group such as a hydrogen atom, an alkyl group or an alkoxy group, or an aromatic functional group such as a phenyl group. R7 and R8 are the same or different. And m and n are positive integers) and triphenylsulfonium triflate, a compound that generates an acid upon actinic radiation, in an organic solvent to obtain a solution of a positive type chemically amplified resist. Was. In a manufacturing process of a recording head, this solution is spin-coated on a multilayer film having a magnetoresistive effect formed on a substrate,
For 5 minutes to obtain a coating film having a thickness of 300 nm.
The substrate was irradiated with an electron beam having an acceleration voltage of 50 keV while scanning, and heat-treated at 80 ° C. for 5 minutes. Next, the substrate was developed using a non-polar organic solvent composed of a mixed solvent of methylene chloride and hexane, and rinsed with pure water. as a result,
An irradiation amount of 30 μC / cm 2 or more provided a good lift-off mask pattern of a reverse taper type. At this time, the height of the obtained lift-off mask pattern was 270 nm, and the height of the tapered portion was 20 nm. As a result, a lift-off mask pattern could be formed on the multilayer film having the magnetoresistive effect of the reproducing head by using a process simpler than the conventional method.

(Example 3) Using the pattern for a lift-off mask formed by the method of Example 1 or 2, an area not covered by the mask was cut by argon ion milling. Thereafter, zirconium oxide as a base film, CoCrPt as a magnetic domain control film, and Ta and TaW as electrode films were deposited at predetermined locations by sputtering. Subsequently, when the substrate was immersed in the stripping solution, the lift-off mask could be easily stripped off using a normal stripping solution. Observation with an optical microscope after peeling revealed that no resist residue or protrusions made of a magnetic or non-magnetic metal material were found on the boundary surface.

Subsequently, on the electrode film and the cut multilayer film having a magnetoresistive effect, Al2O3, SiO2,
Alternatively, an upper gap film made of a mixed film of these is formed by a sputtering method or a CVD method, and NiF is formed thereon.
An upper shield film made of an e-alloy was formed by a plating method.
The cross-sectional shape of the magnetoresistive element viewed from the air bearing surface was an overhang structure in which the magnetic domain control film and the electrode film overlapped the upper end of the magnetoresistive effect film, but the overlapping amount of the magnetic domain control film and the electrode film Was about 20 nm on average. As a result, it was possible to obtain a magnetic head having a smaller output fluctuation than a conventional magnetic head in which a multilayer film having a magnetoresistance effect was cut using a lift-off mask formed by a multilayer resist method.

In the above description, the recording / reproducing separation type magnetic head has been described in detail, but the magnetic random access memory (M
Even if the present invention is applied to a magnetic element such as a RAM) or a thin film inductor, the effect of the present invention is not essentially changed.

[0041]

According to the present invention, it is easier to control the mask pattern shape than the lift-off mask formed by the conventional two-layer resist method, and the number of lithography steps is simple and small.
It was possible to form a lift-off mask pattern that was easy to peel off, and to use this to fabricate a magnetic element and a thin-film magnetic head.

[Brief description of the drawings]

FIG. 1 Flying surface of a head (surface facing a magnetic disk)
Giant magnetoresistive head for reproduction (G
FIG. 3 is a cross-sectional view illustrating a structure of an (MR head).

FIG. 2 is a sectional view showing a manufacturing process of a giant magnetoresistive head (GMR head) as viewed from the air bearing surface of the head.

FIG. 3 is a diagram showing a cross-sectional shape of a lift-off mask pattern as viewed from a floating surface of a head.

FIG. 4 is a view showing a latent image formed on a positive resist coating film by exposure and a cross-sectional shape of a developing pattern.

[Explanation of symbols]

1. Magnetoresistance effect film, 2. Magnetic domain control film, 3. Electrode film, 4. Lower shield layer, 5. Upper shield layer, 6
..Lower insulating film, 7 upper insulating film, 8 lift-off mask, 9 resist film, 10 taper height, 11
.. Exposed part, 12 unexposed part, 13 base film.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 43/08 H01L 43/12 43/12 G01R 33/06 R

Claims (4)

[Claims] In a magnetic element having at least one magnetic separation film, a magnetic material or a non-magnetic material is cut into a predetermined shape after a multilayer film made of a magnetic material and a non-magnetic material is cut into a predetermined shape. The lift-off mask pattern used when laminating at a position is formed by forming a positive-type radiation-sensitive material on a multilayer film made of a magnetic material and a non-magnetic material formed on a predetermined substrate. Spin-coating to form a coating film, a pre-baking step for removing the coating solvent, irradiating the coating film with an actinic ray to form a predetermined pattern latent image, and baking after irradiation. A method for forming a lift-off mask pattern, comprising the steps of: developing with a non-polar organic solvent, leaving an exposed portion to form a negative pattern. 2. A recording / reproducing separation type thin-film magnetic head using a magnetoresistive element as a reproducing element, wherein a magnetoresistive film comprising a multilayer film of a magnetic material and a nonmagnetic material is cut into a predetermined shape by ion milling. The formation of a lift-off mask pattern used when laminating a magnetic domain material and a non-magnetic material constituting a magnetic domain control film and an electrode film at predetermined positions after processing, a magnetic material formed on a predetermined substrate, A step of spin-coating a pattern-forming material made of a positive-type radiation-sensitive material on a magnetoresistive film made of a non-magnetic material to form a coating film, a pre-baking step for removing a coating solvent, Irradiating the film with actinic radiation to form a predetermined pattern latent image, baking after irradiation, and developing with a non-polar organic solvent to leave the exposed portion for magnetoresistance. Liftoff mask pattern forming method characterized by comprising the step of forming a negative pattern on the multilayer film used as an element. 3. A method for manufacturing a magnetic element, comprising using the method for forming a lift-off mask pattern according to claim 1. 4. A method of forming a lift-off mask pattern according to claim 1 or 2 for manufacturing a magnetoresistive element which is a reproducing element of a read / write separated thin film magnetic head. Head manufacturing method.