JP2011171465A - Method for manufacturing exposure mask - Google Patents

Abstract

An object of the present invention is to provide a mask manufacturing method capable of removing charges charged in a resist at the time of second drawing even when a negative resist is used for the first patterning.
[Structure] A step of sequentially forming a conductive light-shielding film and a negative first resist film on a substrate, a ground member is cut so as to penetrate to the layer of the light-shielding film, and the substrate is formed using an electron beam A step of drawing the first pattern on the surface, a step of developing the substrate after drawing, forming a first resist pattern, a step of etching the light-shielding film using the first resist pattern as a mask, and after the etching The step of forming the second resist film and the antistatic film in order on the light-shielding film and the ground so as to penetrate from the upper side of the substrate to the layer of the light-shielding film at a position different from when the first pattern is drawn And a step of drawing a second pattern on the substrate using an electron beam.
[Selection] Figure 1

Description

  The present invention relates to a method for manufacturing an exposure mask, for example, a method for manufacturing an exposure mask in which drawing and development using an electron beam are repeated twice or more.

  Lithography technology, which is responsible for the progress of miniaturization of semiconductor devices, is an extremely important process for generating a pattern among semiconductor manufacturing processes. In recent years, with the high integration of LSI, circuit line widths required for semiconductor devices have been reduced year by year. In order to form a desired circuit pattern on these semiconductor devices, a highly accurate original pattern (also referred to as a reticle or a mask) is required. Here, the electron beam (electron beam) drawing technique has an essentially excellent resolution, and is used for producing a high-precision original pattern.

  FIG. 7 is a conceptual diagram for explaining the operation of the variable shaped electron beam drawing apparatus. The variable shaped electron beam (EB) drawing apparatus operates as follows. In the first aperture 410, a rectangular opening for forming the electron beam 330, for example, a rectangular opening 411 is formed. Further, the second aperture 420 is formed with a variable shaping opening 421 for shaping the electron beam 330 having passed through the opening 411 of the first aperture 410 into a desired rectangular shape. The electron beam 330 irradiated from the charged particle source 430 and passed through the opening 411 of the first aperture 410 is deflected by the deflector, passes through a part of the variable shaping opening 421 of the second aperture 420, and passes through a predetermined range. The sample 340 mounted on a stage that continuously moves in one direction (for example, the X direction) is irradiated. That is, the drawing area of the sample 340 mounted on the stage in which the rectangular shape that can pass through both the opening 411 of the first aperture 410 and the variable shaping opening 421 of the second aperture 420 is continuously moved in the X direction. Drawn on. A method of creating an arbitrary shape by passing both the opening 411 of the first aperture 410 and the variable shaping opening 421 of the second aperture 420 is referred to as a variable shaping method.

  Here, when the above-described exposure mask is manufactured, a film such as a light shielding film, a resist film, and an antistatic film is sequentially formed on the mask substrate, and a series of light shielding processes such as a drawing process, a developing process, and an etching process are performed. A film patterning step is performed. Then, when drawing a pattern, in order to ground the charge charged to the resist film by the electron beam (earth), a member such as a pin is pierced so as to reach the light shielding film from above the substrate. In addition, electric charges are grounded through a light-shielding film having good conductivity. Here, when only a single series of patterning process of the light shielding film is performed, since the light shielding film is usually formed on the entire surface of the mask substrate, the grounding pin is brought into contact with the light shielding film at the time of such drawing. be able to.

  However, when a mask for exposure is manufactured, a series of patterning processes of the light shielding film such as the drawing process, the developing process, and the etching process may be repeated twice or more. For example, when a positive resist is applied on the light shielding film during the first patterning of the light shielding film, an electron beam is not normally shot in a region in contact with the ground pin. Even if it is shot, since the pin covers from above the substrate, the resist film is not irradiated with the electron beam and is not exposed. For this reason, since the resist remains in such a region even after development, the light shielding film remains without being etched. Therefore, in the second patterning of the light shielding film, the light shielding film remains in the region in contact with the ground pin. Therefore, since the earthing pin can be brought into contact with the light shielding film, the charge charged to the resist film through the light shielding film can be grounded.

FIG. 8 is a top conceptual view of a mask arranged on a stage at the time of drawing.
FIG. 9 is a conceptual cross-sectional view of the mask substrate in the second drawing of FIG.
FIG. 8 shows a state where three ground pins 301 are arranged above the mask substrate 300 coated with a resist film or the like. FIG. 9 shows a state where the light shielding film 310, the resist film 320, and the antistatic film 331 are formed on the mask substrate 300. Here, an example is shown in which a positive resist is used for the first patterning of the light shielding film. Therefore, the light-shielding film 310 remains in the region that contacts the pin 301 in the second drawing shown in FIG. Then, a ground fault is caused through the light shielding film 310. Here, conventionally, an example in which a resist film 320 as shown in FIG. 9 is formed inside the light shielding film 310 and the antistatic film 331 so that the antistatic film 331 is in contact with the light shielding film 310 is formed. Is disclosed in the literature (for example, see Patent Literature 1).

JP 2001-230197 A

  As described above, when a positive resist is used in the first patterning of the light shielding film, the light shielding film remains in the region in contact with the grounding pin in the second patterning of the light shielding film. . Therefore, since the earthing pin can be brought into contact with the light shielding film, the charge charged to the resist film through the light shielding film can be grounded. However, when a negative resist is used in the first patterning of the light shielding film, the region in contact with the grounding pin is irradiated with an electron beam because the pin covers the region of the substrate from above. Not exposed. Therefore, since the resist is removed after development in such a region, the light shielding film is etched away.

  FIG. 10 is a conceptual cross-sectional view of the mask substrate in the second drawing when a positive resist is used for the first patterning. FIG. 10 shows an example in which the resist film 322 is formed to the outside of the antistatic film 331. As shown in FIG. 10, as a result of using the negative resist film 322 in the first patterning of the light shielding film 312, the light shielding film 312 does not remain in the region in contact with the grounding pin 301. Therefore, even if the pin 301 is cut from above the substrate, the pin 301 and the light-shielding film 312 do not come into contact with each other, and it is difficult to provide a sufficient ground fault. Even when the resist film 320 as shown in FIG. 9 is formed inside the light shielding film 310 and the antistatic film 331, the same problem occurs when a negative resist is used for the first patterning. As described above, when a negative resist is used for the first patterning, there is a problem that it is difficult to remove the electric charge charged in the resist in the second drawing. However, a method for sufficiently solving such a problem has not been established.

  Accordingly, the present invention provides a method for manufacturing a mask that overcomes such problems and can remove the charge charged in the resist during the second writing even when a negative resist is used for the first patterning. The purpose is to do.

The manufacturing method of the exposure mask of one embodiment of the present invention includes:
Forming a conductive light-shielding film and a negative first resist film on the substrate in order;
A step of drawing a first pattern on the substrate using a charged particle beam in a state where the ground member is cut so as to penetrate from the upper side of the substrate to the light shielding film layer;
Developing the substrate after drawing the first pattern, and forming a first resist pattern with the first resist;
Etching the light-shielding film using the first resist pattern as a mask;
A step of sequentially forming a second resist film and an antistatic film for preventing charging of the second resist on the light-shielding film after etching;
In a state in which the ground member is cut so as to penetrate from the upper side of the substrate to the light shielding film layer at a position different from the position cut when drawing the first pattern, Drawing a second pattern on a substrate using a charged particle beam;
It is provided with.

  With this configuration, it is possible to cut the ground member at a position different from the position cut when drawing the first pattern. Therefore, the ground member can be brought into contact with the light shielding film.

  Further, when drawing the first pattern, it is preferable to expose a position where the ground member is cut when drawing the second pattern.

  In addition, when drawing the second pattern, it is preferable to change the phase in which the substrate is arranged when drawing the first pattern.

  Further, it is preferable that such a phase is changed by rotating the substrate.

The manufacturing method of the exposure mask of one embodiment of the present invention includes:
Forming a conductive light-shielding film and a negative first resist film on the substrate in order;
A step of drawing a first pattern on the substrate using a charged particle beam in a state where the ground member is cut so as to penetrate from the upper side of the substrate to the light shielding film layer;
Developing the substrate after drawing the first pattern, and forming a first resist pattern with the first resist;
Etching the light-shielding film using the first resist pattern as a mask;
Forming a second resist film on the light-shielding film after etching;
When the earth member is cut so as to penetrate from the upper side of the substrate to the layer of the light shielding film, the arrangement position of the substrate is controlled so that the light shielding film exists at the cut position of the earth member, and the earth member is moved to the light shielding film. Drawing the second pattern on the substrate using the charged particle beam in the cut state;
It is provided with.

  According to the present invention, even when a negative resist is used for the first drawing, it is possible to remove the charge charged in the resist during the second drawing. As a result, a pattern can be drawn at a highly accurate position.

1 is a conceptual diagram illustrating a configuration of a drawing apparatus according to Embodiment 1. FIG. FIG. 6 is a process cross-sectional view showing a part of the main part process of the exposure mask manufacturing process in the first embodiment. FIG. 6 is a process cross-sectional view showing the remaining part of the main part process of the exposure mask manufacturing process in the first embodiment. FIG. 3 is a conceptual diagram showing an arrangement position of a mask substrate in the first embodiment. 4 is a top conceptual view showing a mask arrangement position at the time of drawing in the first embodiment. FIG. 6 is a conceptual diagram illustrating an example of a substrate cross section at the time of second drawing in the first embodiment. FIG. It is a conceptual diagram for demonstrating operation | movement of the conventional variable shaping type | mold electron beam drawing apparatus. It is a top surface conceptual diagram of the mask arrange | positioned on the stage in the case of drawing. It is a cross-sectional conceptual diagram of the mask substrate at the time of the second drawing of FIG. It is a cross-sectional conceptual diagram of the mask substrate at the time of the second drawing when a positive resist is used for the first patterning.

Embodiment 1
Hereinafter, in the embodiment, a configuration using an electron beam will be described as an example of a charged particle beam. However, the charged particle beam is not limited to an electron beam, and may be a beam using other charged particles such as an ion beam.

FIG. 1 is a conceptual diagram illustrating a configuration of a drawing apparatus according to the first embodiment.
In FIG. 1, the drawing apparatus 100 includes a drawing unit 150 and a control unit (not shown). The drawing apparatus 100 is an example of a charged particle beam drawing apparatus, and FIG. 1 particularly shows an example of a variable shaping type electron beam drawing apparatus. The drawing unit 150 includes an electron column 102 and a drawing chamber 103.

  In the electron column 102, an electron gun 201, an illumination lens 202, a first aperture 203, a projection lens 204, a deflector 205, a second aperture 206, an objective lens 207, and a deflector 208 are arranged. Yes. An XY stage 105 is disposed in the drawing chamber 103. Support pins 106 that support the substrate 101 so as to be movable up and down are disposed on the XY stage 105, and the substrate 101 that serves as a sample is disposed on the support pins 106. In the substrate 101, a light shielding film and at least a resist film are formed on a quartz substrate serving as a base. It is more preferable that an antistatic film is further formed on the resist film. On the XY stage 105, a grounding member 10 is disposed for grounding (charging) the charge charged on the substrate 101, particularly the charge charged on the resist film during drawing. The ground member 10 has a pin 12 and a support member 14. The ground member 10 is grounded. Then, the support pins 106 are raised in a state where the substrate 101 is arranged, so that the pins 12 cut a film formed on the substrate 101 from above the substrate 101 and connect to the conductive film. In FIG. 1, description of components other than those necessary for describing the first embodiment is omitted. It goes without saying that the drawing apparatus 100 usually includes other necessary configurations.

  The electron beam 200 emitted from the electron gun 201 is collected by the illumination lens 202 and illuminates the entire first aperture 203 having a rectangular hole, for example, a rectangular hole. Here, the electron beam 200 is first formed into a rectangle, for example, a rectangle. Then, the electron beam 200 of the first aperture image that has passed through the first aperture 203 is projected onto the second aperture 206 by the projection lens 204. The position of the first aperture image on the second aperture 206 is controlled by the deflector 205, and the beam shape and size can be changed. Then, the electron beam 200 of the second aperture image that has passed through the second aperture 206 is focused by the objective lens 207, deflected by the deflector 208, and the sample on the XY stage 105 that is movably arranged. The desired position of the substrate 101 is irradiated.

  Further, the inside of the electron column 102 and the drawing chamber 103 in which the XY stage 105 is arranged are evacuated by a vacuum pump (not shown) to form a vacuum atmosphere in which the pressure is lower than the atmospheric pressure.

  FIG. 2 is a process cross-sectional view illustrating a part of the main process of the exposure mask manufacturing process according to the first embodiment. In FIG. 2, each process of the patterning of the 1st light shielding film is shown. In FIG. 2, “A” and “B” indicate different positions on the outer periphery of the substrate.

  In FIG. 2A, as a light shielding film forming step, a conductive light shielding film 30 is formed on the quartz substrate 20. The light shielding film 30 is preferably, for example, a chromium (Cr) film. Further, another film may be formed between the quartz substrate 20 and the light shielding film 30. The light shielding film 30 is preferably formed on the entire surface of the quartz substrate 20. At least the region where the pin 12 pierces is formed.

  In FIG. 2B, as a first resist film formation step, a negative resist material is applied on the light shielding film 30 to form a negative resist film 40 (first resist film).

  In FIG. 2C, as the first antistatic film forming step, an antistatic film 50 for preventing the resist film from being charged by the electron beam 200 is formed on the resist film 40. As the antistatic film 50, for example, a conductive film such as a resin material or ITO is used. The antistatic film 50 is generally made of a material having lower conductivity than the light shielding film 30. Here, the antistatic film 50 is formed, but the present invention is not limited to this, and may be omitted.

  In FIG. 2D, as the first drawing step, the ground member 10, particularly the pin 12 is cut so as to penetrate from the upper side of the substrate 101 to the layer of the light shielding film 30, and the ground member 10 is cut. In this state, a pattern (first pattern) is drawn on the substrate 101 using the electron beam 200. Specifically, the substrate 101 on which the light shielding film 30 and the resist film 40 described above are formed is disposed on the support pins 106. Then, the support pins 106 are raised in a state where the substrate 101 is disposed, whereby the pins 12 cut a film formed on the substrate 101 from above the substrate 101 and connect to the conductive light shielding film 30. In this state, the resist film 40 is exposed by irradiating a predetermined position with a shot 60 of the electron beam 200. In that case, it is normal not to irradiate a beam in the area | region where the earth member 10 is arrange | positioned. Even if irradiated, the resist film 40 does not reach, so in any case, the resist film 40 is not exposed in the region where the ground member 10 is disposed. The charge charged in the resist film 40 by the electron beam 200 flows to the pin 12 through the light shielding film 30 and is grounded. A gap is easily formed between the antistatic film 50 and the pin 12 when the pin 12 is bitten, and the contact area is small. Therefore, even if the antistatic film 50 is conductive, the resistance is higher than that of the light shielding film 30 and the grounding is less likely than that of the light shielding film 30.

  In FIG. 2E, as a first development process, after the pattern is drawn by the first drawing process, the substrate 101 is developed to form a resist pattern 42 (first resist pattern) by the resist film 40. Here, since the electron beam 200 is not irradiated on the outer peripheral portion of the substrate in the region A where the pin is cut, the resist film 40 is not exposed and is removed by development. Further, the resist film 40 is exposed by irradiating the electron beam 200 in the first drawing process on the outer peripheral portion of the substrate in the region B where the pins are not cut. As a result, it remains without being removed by development.

  In FIG. 2F, as a first etching process, the light shielding film 30 is etched using the resist pattern 42 as a mask. The light shielding film 30 is etched and removed because the resist pattern 42 is an opening in the peripheral portion of the substrate in the region A where the pins are cut. On the other hand, since the resist film 40 remains on the outer periphery of the substrate in the region B where the pins are not cut, the light shielding film 30 remains without being etched.

  In FIG. 2G, the first patterning of the light shielding film 30 is completed by removing the resist pattern 42 as the first ashing process.

  FIG. 3 is a process cross-sectional view showing the remainder of the main process of the manufacturing process of the exposure mask in the first embodiment. FIG. 3 shows the second patterning process of the light shielding film. In FIG. 3, the positions of the regions A and B in FIG.

  In FIG. 3A, as a second resist film forming step, a resist material is applied on the light shielding film 30 that has been subjected to the first patterning after the first etching, and a resist film 44 (second resist film). ) Is formed. The resist film 44 may be either a negative type or a positive type. Here, as an example, a case where a negative type is used is shown.

  In FIG. 3B, as a second antistatic film forming step, an antistatic film 52 for preventing the resist film 44 from being charged by the electron beam 200 is formed on the resist film 44. As the antistatic film 52, for example, a conductive film such as a resin material or ITO is used similarly to the antistatic film 50. As with the antistatic film 50, a material having a lower conductivity than the light shielding film 30 is generally used for the antistatic film 52. Here, although the antistatic film 52 is formed, the present invention is not limited to this and may be omitted.

  In FIG. 2C, as the second drawing process, first, from the upper side of the substrate 101 to the layer of the light shielding film 30 at a position different from the position where the pattern was drawn in the first drawing process. The ground member 10, particularly the pin 12 is cut so as to penetrate. Then, a pattern (second pattern) is drawn on the substrate 101 using the electron beam 200 with the ground member 10 cut.

  FIG. 4 is a conceptual diagram showing the arrangement position of the mask substrate in the first embodiment. In FIG. 4, the substrate 101 is covered with the ground member 10 at, for example, three places in the first drawing process. In the second drawing step, the phase at which the substrate 101 is arranged is changed by rotating the substrate 101. In FIG. 4, for example, by rotating 180 degrees, the phase at which the substrate 101 is arranged is changed from when the pattern is drawn in the first drawing process. Here, when the pattern is drawn in the first drawing process, the position where the ground member 10 is cut when the pattern is drawn in the second drawing process is exposed. Thus, in the region (position) where the ground member 10 is cut in the second drawing process, the resist film 40 remains even after the first developing process, and as a result, the light shielding film 30 remains even after the first etching process. be able to. The rotation angle is not limited to 180 degrees. Other angles may be used. The area exposed in the first drawing process may be an area where the ground member 10 is cut in the second drawing process. In other words, when the ground member 10 is cut so as to penetrate from the upper side of the substrate 101 to the layer of the light shielding film 30, the arrangement position of the substrate 101 is set so that the light shielding film 30 exists at the cut position of the ground member 10. Control is sufficient.

  FIG. 5 is a conceptual top view showing a mask arrangement position at the time of drawing in the first embodiment. Since the position of the earth member 10 in the drawing apparatus 100 is the same in both the first drawing process and the second drawing process, the phase of the substrate 101 is changed between the first drawing process and the second drawing process by rotating the substrate 101. Shift.

  FIG. 6 is a conceptual diagram showing an example of a substrate cross section at the time of the second drawing in the first embodiment. The support pins 106 are raised in a state where the substrate 101 is disposed in a state where the substrate 101 on which the light shielding film 30 and the resist film 44 are formed is disposed on the support pins 106, whereby the pins 12 are moved from above the substrate 101 to the substrate A film formed on 101 is cut and connected to the conductive light shielding film 30. In the first embodiment, even if the negative resist film 40 is used during the first patterning, the light shielding film 30 can be left under the region where the ground member 10 is disposed by shifting the position where the substrate 101 is disposed. In this state, the resist film 44 is exposed by irradiating a predetermined position with a shot 62 of the electron beam 200. The charge charged in the resist film 44 by the electron beam 200 flows to the pin 12 through the light shielding film 30 and is grounded. A gap is easily formed between the antistatic film 52 and the pin 12 when the pin 12 is bitten, and the contact area is small. For this reason, even if the antistatic film 52 is conductive, the resistance is higher than that of the light shielding film 30 and the grounding is less likely than that of the light shielding film 30. Therefore, the charges charged in the resist film 44 can be sufficiently released by bringing the pins 12 into contact with the light shielding film 30.

  In FIG. 3D, as a second development process, after the pattern is drawn by the second drawing process, the substrate 101 is developed to form a resist pattern 46 (second resist pattern) by the resist film 44. Here, since the electron beam 200 is not irradiated on the outer peripheral portion of the substrate in the region B where the pin 12 is cut, the resist film 44 is not exposed and is removed by development. Further, in the outer peripheral portion of the substrate in the region A where the pins are not cut, the resist film 44 is exposed by irradiating, for example, the electron beam 200 in the second drawing process. As a result, it remains without being removed by development.

  In FIG. 3E, as a second etching process, the substrate 101 is etched using the resist pattern 46 as a mask. Here, as an example, a case where a Levenson type phase shift mask is manufactured is shown. Therefore, the quartz substrate 20 is dry-etched and dug to a predetermined depth to form the opening 70.

  In FIG. 3 (f), as a wet etching process, the quartz substrate 20 is wet etched to open the opening 70 in an isotropic direction to form an opening 72 that extends in the horizontal direction (direction parallel to the substrate surface). . Then, as a second ashing step, the resist pattern 46 is removed, and the second patterning of the light shielding film 30 is completed.

  By the above, for example, a Levenson type phase shift mask can be manufactured. However, the present invention is not limited to the Levenson type phase shift mask, and patterning for further etching the light shielding film 30 may be performed.

  The embodiments have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. For example, although the case where the pin 12 is used as the ground member 10 is shown, it may be cut from the upper part of the substrate to the light shielding film with a blade-like member instead of the tapered pin-like member.

  In addition, although descriptions are omitted for parts and the like that are not directly required for the description of the present invention, such as a device configuration and a control method, a required device configuration and a control method can be appropriately selected and used. For example, although the description of the control unit configuration for controlling the drawing apparatus 100 is omitted, it goes without saying that the required control unit configuration is appropriately selected and used.

  In addition, all methods of manufacturing an exposure mask that include the elements of the present invention and that can be appropriately modified by those skilled in the art are included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Ground member 12 Pin 14 Support member 20 Quartz substrate 30 Light shielding film 40, 44 Resist film 42, 46 Resist pattern 50, 52 Antistatic film 60, 62 Shot 70, 72 Opening 100 Drawing apparatus 101 Substrate 102 Electronic lens tube 103 Drawing Chamber 105 XY stage 106 Support pin 150 Drawing unit 200 Electron beam 201 Electron gun 202 Illumination lens 203 First aperture 204 Projection lens 205, 208 Deflector 206 Second aperture 207 Objective lens 300 Mask substrate 301 Pins 310, 312 Light shielding film 320, 322 Resist film 330 Electron beam 331 Antistatic film 340 Sample 410 First aperture 411 Opening 420 Second aperture 421 Variable shaping opening 430 Charged particle source

Claims (5)

Forming a conductive light-shielding film and a negative first resist film on the substrate in order;
A ground member is cut so as to penetrate from the upper side of the substrate to the light shielding film layer, and a first pattern is drawn on the substrate using a charged particle beam in a state where the ground member is cut. And a process of
Developing the substrate after drawing the first pattern, and forming a first resist pattern with the first resist;
Etching the light-shielding film using the first resist pattern as a mask;
A step of sequentially forming a second resist film and an antistatic film for preventing charging of the second resist on the light-shielding film after etching;
The ground member is cut so as to penetrate from the upper side of the substrate to the light-shielding film layer at a position different from the position cut when the first pattern is drawn, and the ground member is cut. In a state where a second pattern is drawn on the substrate using a charged particle beam;
A method of manufacturing an exposure mask, comprising:   2. The method of manufacturing an exposure mask according to claim 1, wherein when the first pattern is drawn, a position where the ground member is cut when the second pattern is drawn is exposed.   3. The method of manufacturing an exposure mask according to claim 1, wherein when the second pattern is drawn, a phase in which the substrate is arranged is changed from when the first pattern is drawn.   4. The method of manufacturing an exposure mask according to claim 3, wherein the phase is changed by rotating the substrate. Forming a conductive light-shielding film and a negative first resist film on the substrate in order;
A ground member is cut so as to penetrate from the upper side of the substrate to the light shielding film layer, and a first pattern is drawn on the substrate using a charged particle beam in a state where the ground member is cut. And a process of
Developing the substrate after drawing the first pattern, and forming a first resist pattern with the first resist;
Etching the light-shielding film using the first resist pattern as a mask;
Forming a second resist film on the light-shielding film after etching;
Controlling the arrangement position of the substrate so that the light shielding film exists at the cut position of the ground member when the ground member is cut so as to penetrate from the upper side of the substrate to the layer of the light shielding film; Drawing a second pattern on the substrate using a charged particle beam in a state where the ground member is cut to the light shielding film;
A method of manufacturing an exposure mask, comprising:

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