JP2013029670A - Method of manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a lift-off process to be performed with no restrictions in resist form without requiring the use of a film forming method inferior in step coverage.SOLUTION: After a film 3 to be patterned is formed on a resist 2, corner parts of the film 3 to be patterned is selectively etched by ion irradiation to expose the resist 2. Then, the resist 2 is removed to lift off the film 3 to be patterned on the resist 2, whereby the film 3 to be patterned is patterned. When the lift-off process is performed in this manner, the resist 2 can be exposed by ion irradiation though the film 3 to be patterned is thickly formed on a side surface of the resist 2. Therefore, the thickness of the film 3 to be patterned, on the side surface of the resist 2 is not restricted, so that it is unnecessary to daringly use a film forming method inferior in step coverage and selection of a film forming method superior in step coverage is allowed.

Description

  The present invention relates to a method for manufacturing a semiconductor device having a lift-off process for patterning a film to be patterned into a desired shape by a lift-off method.

  Conventionally, a film to be patterned is patterned into a desired shape using a lift-off method. In the lift-off method, a film to be patterned is placed on a resist exposed to a desired shape, and a portion of the film to be patterned that is placed on the resist is removed together with the resist so that the resist is not formed. The film to be patterned is left. In such a lift-off method, the side surface of the resist needs to be exposed from the film to be patterned at the time of lift-off. Therefore, if the film to be patterned adheres to the side surface of the resist, good lift-off cannot be performed. For this reason, in Patent Document 1, the side surface of the resist is inversely tapered, that is, the angle formed by the side surface of the resist with respect to the surface of the semiconductor substrate or the like on which the resist is disposed is an acute angle.

  Further, as a patterning of a film to be patterned using the lift-off method, there is a method disclosed in Patent Document 2. In this method, the patterning film on the resist side surface is removed by light etching to expose the side surface of the resist, and then the patterning film on the resist is removed together with the resist to cover the area where the resist was not formed. The patterning film is left.

JP 2003-207904 A JP 05-62948 A

  However, as in Patent Document 1, the method of forming the side surface of the resist with an inversely tapered shape requires a method such as using an oblique irradiation component when exposing the resist, and the exposure conditions and the resist used are limited. There is a problem that. Furthermore, a film forming method with poor step coverage must be performed so that the amount of the film to be patterned is reduced on the side surface of the resist. Even if a film formation method with poor step coverage is used, a film to be patterned is formed on the side surface of the resist to some extent, but the film to be patterned that can be formed on the side surface of the resist must be thin. Therefore, the film thickness of the film to be patterned that can be disposed on the resist or in a place where the resist is not disposed is necessarily limited.

  On the other hand, as in Patent Document 2, when the film to be patterned is removed on the side surface of the resist by isotropic etching such as light etching, the etching is performed isotropically, so that the film reduction at the flat portion is also remarkable. Become. For this reason, it can be applied only when the film to be patterned is thin on the side surface of the resist, that is, when a film forming method with poor step coverage is used.

  In view of the above, it is a first object of the present invention to provide a semiconductor device manufacturing method capable of performing a lift-off process that does not require the use of a film formation method with poor step coverage. A second object of the present invention is to provide a semiconductor device manufacturing method capable of performing a lift-off process without limiting exposure conditions and resist used and without using a film forming method with poor step coverage. And

  In order to achieve the above object, according to the first aspect of the present invention, in the lift-off process, after the sacrificial layer (2) is patterned into a desired shape, the surface of the substrate (1) including the surface of the sacrificial layer (2) is covered. A step of forming the patterning film (3) and a step of the patterning film (3) formed on the pattern edge portion of the sacrificial layer (2) by performing ion irradiation from the normal direction to the surface of the substrate (1) Removing the sacrificial layer (2) from the exposed portion of the sacrificial layer (2) by selectively removing the upper corner portion of the sacrificial portion, and exposing the sacrificial layer (2) at the corner portion, Removing a portion of the film to be patterned (3) formed on the sacrificial layer (2) and leaving the film to be patterned (3) in a portion where the sacrificial layer (2) is not formed. It is characterized by doing.

  Thus, the sacrifice layer (2) is exposed by removing the corner of the film to be patterned (3) by ion irradiation, and the sacrifice layer (2) is removed from the exposed portion of the sacrifice layer (2). I am doing so. For this reason, even if the to-be-patterned film (3) is formed thick on the side surface of the sacrificial layer (2), the sacrificial layer (2) can be exposed by ion irradiation. For this reason, since the thickness of the film to be patterned (3) on the side surface of the sacrificial layer (2) is not limited, it is not necessary to use a film forming method with poor step coverage. Therefore, it is possible to perform a lift-off process that does not require the use of a film forming method with poor step coverage.

  In this case, a film forming method with good step coverage can be selected. Vapor deposition is often used as a film formation method with poor step coverage. However, the vapor deposition film has poor film quality or has limited application to refractory materials. By applying CVD, the film quality can be improved and the application limit to the high melting point material can be further increased.

  The invention according to claim 2 is characterized in that, in the ion irradiation, a source gas used for the ion irradiation is one that does not contain an element for chemically etching the material constituting the film to be patterned (3). .

  If it does in this way, it can suppress that the isotropic etching of the to-be-patterned film | membrane (3) is performed simultaneously, and can suppress the film loss in a flat part.

  The invention according to claim 3 is characterized in that the sacrificial layer is a resist (2), and a gas containing oxygen is used as a source gas for ion irradiation.

  In this way, if a gas containing oxygen is mixed with the source gas used for ion irradiation, oxygen plasma is generated, which reacts with the resist material adhering to the patterning film (3) to form a volatile compound. An ashing action of removing can be achieved. According to the manufacturing method of the first aspect, when the resist (2) is exposed and patterned, the side surface of the resist (2) has a forward tapered shape, that is, the substrate (1 of the side surfaces of the resist (2). The resist (2) can be exposed by ion irradiation even when the end on the side) protrudes beyond the end on the opposite side of the substrate (1). For this reason, the exposure conditions and the resist used can be prevented from being restricted. Note that the use of a gas containing oxygen as the ion irradiation source gas may be performed for a certain period of time before the end of ion irradiation or after the end of ion irradiation, as described in claim 4. .

  According to the fifth aspect of the present invention, in the step of exposing the sacrificial layer (2), the surface of the flat portion, which is a portion formed on the surface of the substrate (1), of the patterning film (3) is flattened. It is characterized by ion irradiation.

  In this way, it is possible to prevent a burr shape from remaining at the pattern edge of the film to be patterned (3) that is finally left.

  In the invention described in claim 6, in the lift-off process, after the sacrificial layer (2) is patterned into a desired shape, a film to be patterned (3) is formed on the surface of the substrate (1) including the surface of the sacrificial layer (2). A step of forming a protective film (4) made of a material different from the film to be patterned (3) on the surface of the film to be patterned (3), and a normal to the surface of the substrate (1) By performing ion irradiation from the direction, the upper corner portion of the step portion of the protective film (4) formed on the pattern edge of the sacrificial layer (2) is selectively removed, so that the film to be patterned in the corner portion. The step of exposing (3) and selectively removing the corner of the film to be patterned (3) constituted by the step of the sacrificial layer (2) from the exposed part of the film to be patterned (3), Sacrificing at the corner A step of exposing the sacrificial layer (2) and removing the sacrificial layer (2) from the exposed portion of the sacrificial layer (2), thereby forming a portion of the film to be patterned (3) formed on the sacrificial layer (2). And removing the patterning film (3) and the protective film (4) in the portion where the sacrificial layer (2) is not formed, and the protective film (4) remaining on the patterning film (3) And a step of removing the.

  In this way, a protective film (4) is further formed on the film to be patterned (3) formed on the sacrificial layer (2), and a corner portion of the protective film (4) is selectively formed by ion irradiation. The film to be patterned (3) is exposed by etching. Then, the sacrificial layer (2) is exposed by removing the corner portion of the patterned film (3) from the exposed portion, and then the sacrificial layer (2) is removed from the exposed portion, so that the sacrificial layer (2) The film to be patterned (3) and the protective film (4) on the substrate are lifted off to pattern the film to be patterned (3). Even if it does in this way, the effect similar to Claim 1 can be acquired.

  Also in this case, as described in claim 7, by using a material gas that does not contain an element for chemically etching the material constituting the protective film (4) as the source gas during ion irradiation. The effect similar to that of claim 2 can be obtained.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

It is sectional drawing which showed the mode at the time of the lift-off process among the manufacturing methods of the semiconductor device concerning 1st Embodiment of this invention. It is sectional drawing which showed the mode at the time of the lift-off process demonstrated in the modification of 1st Embodiment. It is sectional drawing which showed the mode at the time of the lift-off process among the manufacturing methods of the semiconductor device concerning 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
A first embodiment of the present invention will be described. Here, a lift-off process performed as a process of the semiconductor device manufacturing method, specifically, a process of patterning a film to be patterned into a desired shape by a lift-off method will be described. For example, the lift-off process is used when patterning an Al wiring as a film to be patterned. FIG. 1 shows a cross-sectional view in the lift-off process, and the lift-off process will be described with reference to this drawing.

[Step shown in FIG. 1 (a)]
First, a substrate 1 serving as a base on which a film to be patterned is formed is prepared by performing a pre-process of a lift-off process. For example, after a device is formed on a semiconductor substrate, a substrate 1 on which an interlayer insulating film is formed on the semiconductor substrate is prepared as the base substrate 1. Then, a resist 2 is applied to the surface of the substrate 1 as a base, and the resist 2 is patterned into a predetermined shape by performing a photolithography process, that is, exposure and development. At this time, the cross-sectional shape of the end portion of the resist 2 does not need to be an inversely tapered shape, and may be a vertical or forward tapered shape.

  Subsequently, a film to be patterned 3 is formed on the entire surface of the substrate 1 and the resist 2. At this time, the film to be patterned 3 may be a single layer film or a multilayer film in which a plurality of layers are laminated.

[Step shown in FIG. 1B]
A step of irradiating the surface of the patterning film 3 with ions from the normal direction of the substrate 1 is performed. Thereby, the film to be patterned 3 is sputter etched. At this time, the efficiency of sputter etching depends on the incident angle of ions with respect to the surface to be sputtered, and the rate is highest when the incident angle is about 40 to 50 degrees. Therefore, as shown in the drawing, the incident angle of ions is the above angle at the most tip position of the corner of the patterning film 3, that is, the step of the patterning film 3 constituted by the step of the resist 2. Therefore, the sputter etching is preferentially performed at the corner portion, and the sputter etching proceeds while maintaining the corner portion shape such that the incident angle of ions becomes the above angle. Thereby, the taper amount becomes large at the corner portion of the film to be patterned 3. At the same time, the flat portion of the patterning film 3 is also sputter-etched, but it is sufficiently smaller than the corner portion.

  As a method of ion irradiation at this time, a method of ionizing a source gas and accelerating it with an acceleration electrode may be used. Alternatively, a substrate 1 may be disposed on the cathode side of an RF plasma generator or the like, and self-biased simultaneously with plasma generation. An RF etching method for generating a voltage may be used. As the ions to be irradiated, any ions may be used as long as they do not contain an element that forms a volatile compound by combining with an element constituting the film to be patterned 3. It is preferable to irradiate relatively heavy particles.

For example, in the case where the film to be patterned 3 is Al, when ion irradiation is performed by an RF etching method using a chlorine-based gas (a gas containing Cl such as Cl ₂ or BCl ₃₎ as a source gas, ions containing Cl A seed is formed. Also in this case, as described above, the corner portion of the film to be patterned 3 is preferentially sputter-etched, but the chlorine-based gas has a chemical etching effect in addition to the physical (sputter) etching effect. Therefore, isotropic etching of the Al film proceeds at the same time. That is, the ratio of the etching rate of the flat portion to the etching rate of the tapered portion of the corner portion of the film to be patterned 3 becomes small, and there is a problem that the film reduction at the flat portion becomes remarkable. For this reason, in the case of Al, it is preferable not to use a chlorine-based gas, to use a gas containing almost no chemical etching effect and containing heavy ions, such as Ar gas. In the case of Al, a fluorine-based gas can also be used. In this way, by using the ion irradiation source gas that does not contain an element that chemically etches the material constituting the film to be patterned 3, the isotropic etching of the film to be patterned 3 can be performed simultaneously. It is possible to suppress the film loss at the flat portion.

[Step shown in FIG. 1 (c)]
When the ion irradiation shown in FIG. 1B is continued, the corner portion of the film to be patterned 3 is removed with priority over the flat portion. Then, since the sputter etching proceeds not only in the thickness direction but also in the lateral direction in the corner portion of the film to be patterned 3, the corner portion is removed while the flat portion is sufficiently left, and the resist 2 is exposed. At this time, ion irradiation is terminated. For the detection of the end point, for example, a general plasma spectroscopic analysis can be used focusing on the light emission of the constituent material of the resist 2.

  At the end point, the resist 2 only needs to be exposed, and the amount of exposure does not matter. However, if the exposure amount is too small, it takes time for the chemical solution to hardly penetrate when the resist 2 is peeled off in the subsequent process. Conversely, if the exposure amount is increased, the ion irradiation time becomes longer. It is preferable to determine the irradiation time.

  In addition, since the resist 2 is exposed and sputter-etched at the end of ion irradiation, the sputter-etched resist material may reattach to the upper portion of the remaining portion of the patterning film 3 and may remain after the process is completed. . Therefore, if a gas containing oxygen (oxygen gas or a gas in which oxygen and other elements are mixed) is mixed with the source gas used for ion irradiation, oxygen plasma is generated and adhered to the film to be patterned 3. An ashing action of reacting with the resist material to form and remove a volatile compound can be achieved. For this reason, it is preferable to mix a gas containing oxygen with the source gas used for ion irradiation. In this way, the source gas used for ion irradiation may be mixed with a gas containing oxygen only at the end of ion irradiation. The same effect can also be obtained by stopping the introduction of the source gas and irradiating the gas containing oxygen with ions.

[Step shown in FIG. 1 (d)]
A step of removing the resist 2 is performed. For example, a general resist stripping process using a dedicated stripping solution for resist 2 or an organic solvent as a chemical solution is performed. As a result, the chemical solution permeates from the exposed portion of the resist 2 so that the resist 2 is dissolved and removed, and the patterned film 3 formed on the resist 2 is simultaneously removed by lift-off, thereby forming the resist 2. The film to be patterned 3 remains at the position where it has not been formed, and the film to be patterned 3 is patterned into a desired shape.

  Thereafter, the semiconductor device is completed by performing an interlayer insulating film forming step, a protective film forming step, and the like on the patterned film 3 as necessary.

  As described above, in the present embodiment, after the patterned film 3 is formed on the resist 2, the resist 2 is exposed by selectively etching the corner portion of the patterned film 3 by ion irradiation. I have to. Then, by removing the resist 2, the patterning film 3 on the resist 2 is lifted off, and the patterning film 3 is patterned.

  Since the lift-off process is performed in this way, the resist 2 can be exposed by ion irradiation even if the patterned film 3 is formed thick on the side surface of the resist 2. For this reason, since the thickness of the film to be patterned 3 on the side surface of the resist 2 is not limited, it is not necessary to use a film forming method with poor step coverage, and a film forming method with good step coverage can be selected. it can. Vapor deposition is often used as a film formation method with poor step coverage. However, the vapor deposition film has poor film quality or has limited application to refractory materials. By applying CVD, the film quality can be improved and the application limit to the high melting point material can be further increased.

  In addition, since there is no problem even if the film to be patterned 3 adheres to the side surface of the resist 2, it is not necessary to make the side surface of the resist 2 have a reverse taper shape. Therefore, it is not necessary to use a special resist or irradiation conditions in order to make the side surface of the resist 2 have an inversely tapered shape. On the contrary, the side surface of the resist 2 has a forward taper shape, that is, even if the end portion on the substrate 1 side of the side surface of the resist 2 protrudes from the end portion on the opposite side to the substrate 1, The resist 2 can be exposed. For this reason, exposure conditions are not limited.

(Modification of the first embodiment)
In the first embodiment, the end point of ion irradiation is assumed to be when the resist 2 is exposed. However, the end of the patterning film 3 that is finally left remains in a burr shape, that is, partially thick in the thickness direction. May take shape. If such a burr shape remains, it may be undesirable when another film is formed on the film to be patterned 3 in a later step.

  For this reason, as shown in FIG. 2A, the ion irradiation described in the process shown in FIG. 1C is set longer, and the amount of sputter etching in the lateral direction of the film to be patterned 3 is increased, Ion irradiation is performed until the end of the flat portion of the film to be patterned 3 becomes flat. That is, ion irradiation is performed until a portion (burr shape) attached to the side surface of the resist 2 in the film to be patterned 3 disappears. By limiting to these end points, as shown in FIG. 2B, when the step of removing the resist 2 described in the step shown in FIG. 1D is performed, the remaining patterning film 3 is removed. The surface of the flat part is all flat. Accordingly, it is possible to prevent the burr shape from remaining at the end of the patterning film 3 that is finally left.

(Second Embodiment)
A second embodiment of the present invention will be described. In the present embodiment, the lift-off process is partially changed with respect to the first embodiment, and the other parts are the same as those in the first embodiment. Therefore, only the parts different from the first embodiment will be described.

  FIG. 3 shows a cross-sectional view in the lift-off process according to the present embodiment, and the lift-off process will be described with reference to this figure.

[Step shown in FIG. 3 (a)]
First, similarly to the process of FIG. 1A of the first embodiment, after preparing the substrate 1, the resist 2 is arranged thereon and patterned into a desired shape by exposure. Subsequently, after a film to be patterned 3 is formed on the entire surface of the substrate 1 and the resist 2, a protective film 4 made of a material different from the film to be patterned 3 is formed thereon. At this time, it is preferable to make the thickness of the protective film 4 smaller than the thickness of the film to be patterned 3. The protective film 4 may be any material that has high etching selectivity with respect to the film to be patterned 3 and is difficult to be etched when the film to be patterned 3 is etched. For example, when the film to be patterned 3 is made of Al, it is SiO. ₂ or the like can be used.

[Step shown in FIG. 3B]
As in the process of FIG. 1B of the first embodiment, a process of irradiating the surface of the protective film 4 with ions from the normal direction of the substrate 1 is performed. Thereby, the protective film 4 is sputter-etched. Also in this case, since the sputter etching efficiency depends on the ion incident angle, the corner portion of the protective film 4 is preferentially sputter etched, and the sputter etching proceeds at an ion incident angle of 45 degrees. Go. Thereby, the taper amount becomes large at the corner portion of the protective film 4. At the same time, the flat portion of the protective film 4 is also sputter-etched, but it is sufficiently smaller than the corner portion.

  Then, ion irradiation is continued, and in the corner portion of the protective film 4, the sputter etching proceeds not only in the thickness direction but also in the lateral direction. Therefore, the corner portion is removed with the flat portion sufficiently left, and the film to be patterned 3 is exposed. At this time, ion irradiation is terminated. At this time, if the thickness of the protective film 4 is made smaller than that of the film to be patterned 3 as described above, the corner portion of the protective film 4 can be removed more quickly.

[Step shown in FIG. 3 (c)]
Using the protective film 4 as a mask, a step of removing the corner portion of the patterned film 3 through the opening of the corner portion of the protective film 4 is performed. For example, when the film to be patterned 3 is made of Al, dry etching using chlorine gas plasma can be applied. Under isotropic etching conditions, the etching proceeds isotropically with the opening as the center, and the resist 2 can be exposed by removing the corner of the film to be patterned 3 as shown. Further, when the film to be patterned 3 is made of Al, wet etching using phosphoric acid or the like can be applied, but it can be said that dry etching is preferable because controllability is better.

[Step shown in FIG. 3 (d)]
Similar to the step of FIG. 1D of the first embodiment, the step of removing the resist 2 is performed. As a result, the chemical solution penetrates from the exposed portion of the resist 2 so that the resist 2 is dissolved and removed, and the patterned film 3 and the protective film 4 formed on the resist 2 are simultaneously removed. The film to be patterned 3 and the protective film 4 remain at a position where no is formed.

[Step shown in FIG. 3 (e)]
A step of removing the protective film 4 remaining on the film to be patterned 3 is performed. For removing the protective film 4, any etching method having high selectivity with respect to the film to be patterned 3 may be used. For example, when the protective film 4 is made of SiO ₂ , a fluorine-based gas is used. The protective film 4 can be removed by dry etching using. Further, wet etching such as HF may be used. However, since the film to be patterned 3 is left, it is necessary to mix glycerin in order to increase the selectivity with respect to the film to be patterned 3.

  Thereafter, the semiconductor device is completed by performing an interlayer insulating film forming step, a protective film forming step, and the like on the patterned film 3 as necessary.

  As described above, in this embodiment, the protective film 4 is further formed on the film to be patterned 3 formed on the resist 2, and the corner portion of the protective film 4 is selectively etched by ion irradiation. Thus, the patterning film 3 is exposed. Then, the resist 2 is exposed by removing the corner portion of the patterned film 3 from the exposed portion, and then the resist 2 is removed from the exposed portion, so that the patterned film 3 and the protective film 4 on the resist 2 are removed. The film to be patterned 3 is patterned. Even if it does in this way, the effect similar to 1st Embodiment can be acquired.

(Other embodiments)
In the above embodiment, the resist 2 is taken as an example of the sacrificial film to be lifted off. However, the present invention is not limited to the case where the resist 2 is used. For example, if a material that does not deteriorate during heating is used as a sacrificial film, a high-temperature process can be applied as a method for forming the film to be patterned 3, and options for the material and film forming method for the film to be patterned 3 can be expanded. It becomes.

  In each of the above embodiments, the substrate 1 on which a device is formed on a semiconductor substrate is taken as an example as a base on which the film to be patterned 3 is formed. However, the substrate 1 is not necessarily a semiconductor substrate on which a device is formed. Alternatively, another layer may be formed on the surface of the semiconductor substrate.

1 Substrate 2 Resist 3 Patterned Film 4 Protective Film

Claims (7)

After the sacrificial layer (2) is formed on the surface of the substrate (1) constituting the base surface, the sacrificial layer (2) is patterned into a desired shape, and then the surface of the sacrificial layer (2) is patterned. A lift-off step of patterning by forming a film (3) and removing the sacrificial layer (2), thereby leaving the film to be patterned (3) in a portion where the sacrificial layer (2) has not been formed. A method of manufacturing a semiconductor device including:
In the lift-off process,
Forming the film to be patterned (3) on the surface of the substrate (1) including the surface of the sacrificial layer (2) after patterning the sacrificial layer (2) into a desired shape;
By performing ion irradiation from the normal direction to the surface of the substrate (1), the upper corner portion of the stepped portion of the patterned film (3) formed on the pattern edge portion of the sacrificial layer (2) is selected. Removing the sacrificial layer (2) at the corner by removing the
By removing the sacrificial layer (2) from the exposed portion of the sacrificial layer (2), a portion of the film to be patterned (3) formed on the sacrificial layer (2) is removed, And a step of leaving the film to be patterned (3) in a portion where the sacrificial layer (2) is not formed.   2. The semiconductor according to claim 1, wherein in the ion irradiation, a source gas used for the ion irradiation is one that does not contain an element that chemically etches a material constituting the film to be patterned (3). Device manufacturing method.   The method of manufacturing a semiconductor device according to claim 1, wherein the sacrificial layer is a resist (2), and a gas containing oxygen is used as a source gas for the ion irradiation.   The sacrificial layer is a resist (2), and a gas containing oxygen is used as a source gas for the ion irradiation for a certain time before the ion irradiation ends or after the ion irradiation ends. Or the manufacturing method of the semiconductor device of 2.   In the step of exposing the sacrificial layer (2), the ion irradiation is performed until the surface of the flat portion, which is the portion formed on the surface of the substrate (1), of the film to be patterned (3) becomes flat. The method of manufacturing a semiconductor device according to claim 1, wherein: After the sacrificial layer (2) is formed on the surface of the substrate (1) constituting the base surface, the sacrificial layer (2) is patterned into a desired shape, and then the surface of the sacrificial layer (2) is patterned. A lift-off step of patterning by forming a film (3) and removing the sacrificial layer (2), thereby leaving the film to be patterned (3) in a portion where the sacrificial layer (2) has not been formed. A method of manufacturing a semiconductor device including:
In the lift-off process,
Forming the film to be patterned (3) on the surface of the substrate (1) including the surface of the sacrificial layer (2) after patterning the sacrificial layer (2) into a desired shape;
Forming a protective film (4) made of a material different from the film to be patterned (3) on the surface of the film to be patterned (3);
By performing ion irradiation from the normal direction to the surface of the substrate (1), the upper corner portion of the step portion of the protective film (4) formed on the pattern edge portion of the sacrificial layer (2) is selectively selected. Removing the film to be patterned (3) at the corner,
By selectively removing the corner portion of the patterning film (3) constituted by the step of the sacrificial layer (2) from the exposed portion of the patterning film (3), the sacrificial layer at the corner portion is removed. Exposing (2);
By removing the sacrificial layer (2) from the exposed portion of the sacrificial layer (2), a portion of the film to be patterned (3) formed on the sacrificial layer (2) is removed, Leaving the film to be patterned (3) and the protective film (4) in a portion where the sacrificial layer (2) has not been formed;
And a step of removing the protective film (4) remaining on the film to be patterned (3).   7. The semiconductor device according to claim 6, wherein in the ion irradiation, a source gas used for the ion irradiation is a material gas that does not contain an element that chemically etches a material forming the protective film. Production method.

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