JP3750312B2 - Phase shift mask and method of manufacturing phase shift mask - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a phase shift mask and a method of manufacturing a phase shift mask. In particular, the present invention provides a phase shift mask capable of pattern exposure without causing a waveguide effect, and capable of cleaning the mask, and a manufacturing method thereof. The present invention can be applied to various exposure techniques for transferring an image of a mask onto a material to be exposed. For example, a phase shift mask used for pattern transfer for manufacturing a miniaturized and integrated electronic material (semiconductor device, etc.) and As its production method, it can be suitably used.
[0002]
[Prior art]
  Conventionally, in the field of electronic materials such as semiconductor devices, it is known to form various patterns by pattern transfer. For example, in the pattern transfer process when manufacturing various semiconductor devices such as a memory element, a logic operation element, a CCD element, an LCD element, and a memory logic operation mixed element, a so-called photolithography process is performed. The circuit pattern formed on the resist is coated on a semiconductor wafer substrate, which is the material to be exposed, by, for example, light having a wavelength from the ultraviolet to the visible region, and the resist is developed to form a desired circuit pattern. .
[0003]
  In recent years, with the miniaturization of semiconductor devices, the line width or hole diameter of circuit patterns formed by developing a resist applied on a wafer substrate has been increasingly reduced, and the wavelength of light used for transfer. Circuit patterns having smaller line widths or hole diameters are being formed.
[0004]
  For example, it is required that the line width or the hole diameter be 0.24 μm or smaller than that by light having a wavelength of 248 nm.
[0005]
  In this case, it is required to form a very fine pattern. In such a case, for example, when it is required to form a line width or a hole diameter smaller than the wavelength of light as described above, the phase shift mask is used. The use of is being considered. A phase shift mask is attracting attention as a technique capable of improving resolution and depth of focus, and several types are known.
[0006]
  For example, a repetitive pattern in which the line width and the space width are substantially equal (hereinafter also referred to as a line and space pattern as appropriate), or a pattern in which the hole diameter is substantially equal to the interval between adjacent holes (hereinafter referred to as a dense hole as appropriate). It is known that a Levenson-type phase shift mask is remarkably effective for dense patterns such as patterns (sometimes referred to as patterns).
[0007]
  The Levenson phase shift mask is typicallyFIG.As shown in FIG. 3, the light-shielding portion 2 made of a light-shielding film and two light transmission patterns 3A and 3B that transmit light while making the phase of transmitted light different from each other by about 180 degrees are used. Thus, a pattern with high resolution is formed. Figure26In this example, the light transmission pattern 3A is formed by digging a transparent substrate 1 (transparent to exposure light) such as glass, so that the phase is different from that of the light transmission pattern 3B by about 180 degrees.
[0008]
  However, in the phase shift mask, the two light transmission patterns 3A and 3B transmit light with the phases of the light transmitted through them different from each other by approximately 180 degrees. The light intensities applied to each other may be different from each other. That is, in the illustrated prior art, due to the waveguiding effect,26As indicated by reference characters Fa and Fb in the light intensity graph, the light intensities of the light transmitted through the adjacent light transmission regions (patterns 3A and 3B) are different from each other. For this reason, the widths of the patterns formed on the resist coated on the wafer, which is the material to be exposed, are different.
[0009]
  To avoid this problem, this type of phase shift mask is27As shown in FIG. 2, it is proposed that the light shielding film 2 is formed in a bowl shape with respect to one light transmission pattern 3A, and the waveguide effect is eliminated or reduced by the collar 21 of the light shielding film. In this structure, the light-shielding film is left in a bowl shape of about 0.10 μm in the light transmission pattern 3A formed by digging.
[0010]
  This structure is28From figure34It is produced by the method shown in FIG. Figure28As shown in FIG. 3, a light shielding film 20 is formed of chromium on a glass substrate 1 which is a transparent substrate (transparent to exposure light when used as a mask), and an electron beam resist 1a is further formed. Figure28The first electron beam drawing scheduled area is indicated by reference numerals R11 and R12.
[0011]
  In accordance with the patterning of the electron beam resist 1a by electron beam drawing, the regions R11 and R12 are drawn and etched,29Get the structure of.As a result, the light shielding film 20 isPaThe light shielding part 2 is formed by turning. Strip the resist30Get the structure.
[0012]
  An electron beam resist 1a is applied again to the above structure, and an antistatic film 1b is formed thereon.31The structure is as follows. A second electron beam drawing scheduled area is denoted by reference symbol R2.
[0013]
  The second electron beam drawing is performed, and the region R2 is drawn and etched.32As shown in FIG. 2, the base 1 in the region R2 is exposed. This corresponds to the step of opening the etching region of the substrate 1.
[0014]
  Isotropic etching is performed to etch the substrate 1. Because it is isotropic etching,33As described above, the light shielding film 2 remains in the shape of the ridge 21 above the etched portion. When the resist is removed,34The following structure is obtained.
[0015]
  Figure34When exposed with a mask of the structure27As shown, the intensity FA of light transmitted through the region 3A and the intensity FB of light transmitted through the region 3B are substantially equal.
[0016]
[Problems to be solved by the invention]
  The above method has the following problems. That is, in the above method, the glass substrate 1 is wet-etched, and the length of the flange 21 of the light-shielding film 2 is controlled by this wet etching, but this has the following drawbacks.
[0017]
  First, since isotropic wet etching is used, the bottom of the pattern formed by digging the glass substrate 1 is rounded. Due to the rounding, the phase shifts from the 180 degree inversion, so that the pattern transfer characteristics deteriorate. Furthermore, the length of the wrinkles by the light-shielding film can be controlled by wet etching solvent, wet etching time, etc., but when there are mixed patterns with different line widths or hole diameters, the etching rate depends on the pattern size. Since they are different, the lengths of the wrinkles differ from each other depending on the pattern size.
[0018]
  In addition, since the wrinkle made of a light shielding film has a structure floating in the air, scribing, ultrasonic cleaning, megasonicTsuIt can be easily removed by cleaning, etc., and the function as a trap for eliminating or reducing the waveguide effect is lost. Moreover, it becomes dust and contaminates the manufacturing apparatus. For example, the phase shift mask obtained in the above process is subjected to ultrasonic cleaning for 10 minutes,TsuWhen a cleaning test was performed under the conditions of 15 minutes for scrubbing and 10 minutes for scribing, the wrinkles of the light-shielding film (chrome) were peeled off. Therefore, cleaning is impossible, and cleaning of this type of phase shift mask must be avoided.
[0019]
  In addition, the figure28Or34In the manufacturing process shown in FIG. 1, the length of the ridge of the light-shielding film (chrome) is left and right because of the positional deviation of the second drawing process relative to the first drawing process (the positional deviation cannot be completely eliminated). They cannot be formed identically, and therefore the waveguide effect cannot be completely suppressed, and unevenness in light intensity occurs between a pattern in which a glass substrate is digged and a pattern in which adjacent digs are not digged.
[0020]
  The present invention solves the above-mentioned problems and makes it possible to eliminate or reduce the waveguide effect satisfactorily for the phase shift mask, and to obtain this effect with good control without depending on the pattern size or the like. An object of the present invention is to provide a phase shift mask that can be used for various types of cleaning, and a manufacturing method thereof.
[0021]
[Means for Solving the Problems]
  The above object is achieved by the following invention. That is,
  A light-shielding portion made of a light-shielding film and a first pattern and a second pattern, which are light transmission patterns, are formed on a substrate transparent to exposure light, and the first pattern is formed by digging the substrate. In the phase shift mask, the phase of the light transmitted through the first pattern and the light transmitted through the second pattern is approximately 180 degrees different.
  A sidewall pattern is formed on the sidewall of the first pattern,
  The light shielding film on the first pattern side is formed so as to overlap the sidewall,
  The light shielding film on the sidewall pattern or the sidewall pattern eliminates or reduces the waveguide effect,
  The line width of the pattern transferred onto the exposed material by the light transmitted through the first pattern is substantially equal to the line width of the pattern transferred onto the exposed material by the light transmitted through the second pattern. did
  Phase shift mask characterized by
Is achieved by
[0022]
    Also,
  Forming a first pattern by digging a substrate transparent to exposure light, forming a sacrificial film, etching back the sacrificial film, and forming a light-shielding film on the substrate And a step of forming a second pattern on the light shielding film,
  The phase of the light transmitted through the first pattern and the light transmitted through the second pattern is approximately 180 degrees different from each other.
  On the side wall of the first pattern, a sacrificial film forming material remaining in the step of etching back the sacrificial film is formed in a sidewall shape.
  The light shielding film on the first pattern side is formed so as to overlap at least a part of the sidewall;
  The light shielding film on the side wall or side wall eliminates or reduces the waveguide effect,
  The line width of the pattern transferred onto the exposed material by the light transmitted through the first pattern is substantially equal to the line width of the pattern transferred onto the exposed material by the light transmitted through the second pattern. Form a mask so that
  Manufacturing method of phase shift mask
Is achieved by
0023]
  According to the present invention, by forming a side wall on the side wall of a pattern formed by digging a transparent base, the side wall pattern makes it remarkable in the case where there is no such side wall. By suppressing the light interference effect, the waveguide effect can be eliminated or reduced. That is, when the sidewall is formed of a material having a light shielding effect, the sidewall itself is formed. When the sidewall is formed of a transparent or translucent material, a light shielding film on the sidewall is formed. It shows the action of suppressing the interference effect of light on the side wall and eliminating or reducing the waveguide effect.
0024]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, embodiments of the present invention will be described in more detail, and specific examples of preferred embodiments of the present invention will be described with reference to the drawings. However, as a matter of course, the present invention is not limited to the embodiments described below.
0025]
  In the practice of the present invention, a substrate that is transparent to the exposure light used for exposure (completely does not require 100% transmittance, but may be transparent enough to be used for exposure). Typically, it is a quartz substrate. In addition, a substrate of an appropriate material such as glass can be used.
0026]
  The material of the light shielding film constituting the light shielding portion is typically chromium or tungsten, or other refractory metal or a compound thereof can be used.
0027]
  Hereinafter, preferred embodiments of the present invention will be described in detail. As a matter of course, the present invention is not limited to the embodiments described below. In the following embodiments, a line and space pattern will be described as an example. Of course, the present invention can be similarly applied to a hole pattern repeatedly arranged. Furthermore, the present invention can be similarly applied to an arbitrary device pattern composed of repeated patterns. Further, although the drawing method is exemplified by a method using an electron beam, it is not limited to an electron beam, and may be light, a laser beam, an ion beam, or the like. In addition to the materials shown in the following examples, the material of the sacrificial film is SiO 2₂, Ti, Ta, W, Al, spin-on glass and the like, various amorphous or inorganic crystal grains having a small crystal grain size, and the like, and organic substances such as hard-baked resists may be used. The light-shielding material for forming the light-shielding film may be any material as long as it has a light-shielding ability in addition to a chromium-based or refractory metal-based material. For example, other metal-based materials, various alloys, etc. may be appropriately selected. Can be used.
  Note that the pattern widths exemplified in the following embodiments are displayed with dimensions on a 5-fold reticle.
0028]
Embodiment 1
  FIG. 1 shows the structure of the phase shift mask according to this example, FIG. 2 shows the operation thereof, and FIGS. 3 to 9 show the manufacturing steps of the phase shift mask of this example.
0029]
  In this example, a step of forming a first pattern by digging a substrate transparent to exposure light, a step of forming a sacrificial film, a step of etching back the sacrificial film, and a light shielding film on the substrate And a step of forming a second pattern on the light shielding film, and the phase of the light transmitted through the first pattern and the light transmitted through the second pattern is approximately 180 degrees different from each other. A sacrificial film forming material remaining in the step of etching back the sacrificial film is formed in a sidewall shape on the sidewall of the first pattern, and the light shielding film on the first pattern side is formed so as to overlap the sidewall. The pattern line transferred onto the exposed material by the light transmitted through the first pattern by the waveguide or the light shielding film on the sidewall disappearing or reducing the waveguide effect. When the method of manufacturing a phase shift mask and the line width of a pattern to be transferred onto the exposed material by light transmitted through the second pattern is a mask formed so as to be approximately equal, was performed embodied.
0030]
  As shown in FIG. 1, the phase shift mask of this example includes a light-shielding portion 2 made of a light-shielding film on a substrate 1 (here, a glass substrate) that is transparent to exposure light, and a first pattern that is a light transmission pattern. 3A and the second pattern 3B are formed, and the first pattern 3A is formed by digging the base body 1 and transmits the light transmitted through the first pattern 3A and the second pattern 3B. In the phase shift mask in which the phase of light is approximately 180 degrees different, a sidewall pattern 4 (made of silicon nitride in this case) is formed on the sidewall of the first pattern 3A. When the light shielding film 5 eliminates or reduces the waveguide effect, the line width of the pattern transferred onto the exposed material by the light transmitted through the first pattern 3A and the second pattern 3B are transmitted. And the line width of a pattern to be transferred onto the exposed material by light and is a phase shift mask was substantially equal.
0031]
  As shown in FIG. 2, the phase shift mask eliminates or reduces the waveguide effect by the action of the sidewall pattern 4 or the light shielding film 5 on the sidewall pattern 4, and transmits light transmitted through the first pattern 3A. And the intensity FB of the light transmitted through the second pattern 3B are substantially equal. This effect will be described in detail later.
0032]
  Hereinafter, the manufacturing process of the phase shift mask of this example will be described with reference to FIGS.
  As shown in FIG. 3, the electron beam resist 1a was spin-coated on the glass substrate 1 so as to have a film thickness of 500 nm. On the electron beam resist 1a, an antistatic film 1b was formed. Next, in the step shown in FIG. 3, the resist 1 in the first drawing planned region I was drawn with an electron beam. Here, an electron beam acceleration voltage of 10 kV was used. The width of the pattern was 1.40 μm.
0033]
  Next, as shown in FIG._FourEtching was performed to a depth of 269 nm by reactive ion etching (RIE) using an etching gas composed of a gas. Thus, the first pattern 3A was formed by digging the glass substrate 1. Here, the depth of 269 nm is transmitted through the region 3A (the region of the first pattern 3A) shown in FIG. 1 and the phase of light having a wavelength of 248 nm and the region 3B (the region of the second pattern 3B). The phase of light having a wavelength of 248 nm is set to be 180 degrees different from each other.
0034]
  Next, in the step shown in FIG._ThreeN_FourThe film was formed to a thickness of 300 nm. Si_ThreeN_FourThe film is made of SiH by low pressure CVD._FourGas and NH_ThreeA gas was used as a source gas. The reaction temperature was approximately 800 ° C. Here, the sacrificial film means a film that does not remain in the final structure (although it remains as a sidewall here).
0035]
  Next, in the process shown in FIG._FourSi, which is the sacrificial film 6, using a reaction gas composed of oxygen and oxygen_ThreeN_FourThe film was etched back. In this step, Si formed on the side wall of the glass substrate 1_ThreeN_FourSince the film is formed thicker than 300 nm, it remains as a sidewall even in the etch back process. The back etching time was controlled so that the side wall width at the bottom of the glass substrate pattern was 0.10 μm. As a result, the sidewall pattern 4 shown in FIG. 6 was left on the sidewall of the first pattern 3A in the step of etching back the sacrificial film 6.
0036]
  Next, in the process shown in FIG. 7, here, the light shielding film 20 made of chromium is applied to the DC spacer.PaIt was formed by the clutter method. The film thickness of the chromium film constituting the light shielding film 20 was 105 nm.
0037]
  Next, in the step shown in FIG. 8, an electron beam resist 7 was applied. In FIG. 8, reference numerals IIa and IIb indicate the second drawing scheduled areas.
0038]
  These regions IIa and IIb were drawn with an electron beam having an acceleration voltage of 10 kV in accordance with the second drawing scheduled regions IIa and IIb shown in FIG. The width of the pattern was 1.20 μm.
0039]
  Next, in the process of FIG. 9, the light shielding film 20 is etched using the patterned resist 7 formed by the electron beam drawing as a mask.PaTurned. Here, etching was performed by RIE using an etching gas composed of chlorine and oxygen to form a light shielding portion 2 having a predetermined pattern.
0040]
  The resist 7 was peeled off to obtain a phase shift mask having the structure shown in FIG. The width of the pattern formed in FIG. 1 was 1.20 μm between the sidewalls of the pattern 3A, and the width of the pattern B was 1.20 μm.
0041]
  The operation of the phase shift mask of this example will be described. In this example, chromium forming the light shielding film 2 is deposited on the sidewall pattern 4 of FIG. For this reason, for example, the light transmission region (first pattern 3A) of the portion of the glass substrate 1 that is dug and the light transmission region (second pattern 3B) of the portion that is not dug are repeatedly formed. In the pattern arrangement, the intensities FA and FB (FIG. 2) of the light transmitted through the regions A and B (first pattern 3A and second pattern 3B) are substantially equal.
0042]
  Such light intensity is schematically shown in FIG. As shown in FIG. 2, the intensities FA and FB of light transmitted through the areas A and B (first pattern 3A and second pattern 3B) are substantially equal.
0043]
  That is, the light shielding film 5 deposited on the side wall 4 does not cause diffraction of transmitted light on the side wall of the glass substrate 1, and therefore does not cause a so-called waveguide effect. Further, the width of the sidewall 4 can be precisely controlled by the thickness of the sacrificial film 6 in the process of FIG. 5 and the etch back conditions in the process of FIG..For example, in the present embodiment, the sidewall width can be formed from 0.05 μm to 0.15 μm with an accuracy of 3σ 0.01 μm in the mask pattern formation region.
0044]
  Further, the phase shift mask manufactured in this embodiment is subjected to ultrasonic cleaning for 10 minutes,TsuWhen a cleaning test was performed under conditions of 15 minutes for scrubbing and 10 minutes for scribing, in any case, peeling of the film or the like did not occur, and it was possible to clean well.
0045]
  As described above, the phase shift mask of the present example is a pattern transfer that does not cause a waveguide effect in the Levenson-type phase shift mask by forming a sidewall pattern, and thus does not have a non-uniform line width. And has the advantage of being washable.
0046]
  Embodiment 2
  This embodiment is an embodiment of the same invention as the first embodiment. However, in this example, the sacrificial film is formed from a light shielding material, and therefore the sidewall pattern itself has a light shielding effect.
0047]
  That is, in the phase shift mask of this example, as shown in FIG. 10, the sidewall pattern 4 on the side wall of the first pattern 3C, which is a light transmission region, is made of a light shielding material (here, tungsten nitride is used). Prevent or suppress the waveguide effect. In this example, it is not necessary that the light shielding portion 2 is placed on the sidewall pattern 4.
0048]
  Hereinafter, the manufacturing process of the phase shift mask of this example will be described with reference to FIGS.
  As shown in FIG. 11, the electron beam resist 1a was spin-coated on the glass substrate 1 so as to have a film thickness of 500 nm. On the electron beam resist 1a, an antistatic film 1b was formed. Next, in the step shown in FIG. 11, the resist 1 in the first drawing planned area I was drawn with an electron beam. Here, an electron beam acceleration voltage of 10 kV was used. The width of the pattern was 1.40 μm.
0049]
  Next, in the step shown in FIG._FourEtching was performed to a depth of 269 nm by reactive ion etching (RIE) using an etching gas composed of a gas. Thus, the first pattern 3C was formed by digging the glass substrate 1. Here, the reason why the depth is 269 nm is the same as in the first embodiment, and the phase of the light with a wavelength of 248 nm transmitted through the region 3C (region of the first pattern 3C) shown in FIG. The phase of light having a wavelength of 248 nm that transmits through the region 3D (region of the second pattern 3D) is set to be 180 degrees different from each other.
0050]
  Next, in the step shown in FIG. 13, a tungsten nitride film to be the sacrificial film 6 was formed to a thickness of 300 nm. The tungsten nitride (WNx) film is formed by WF using the plasma CVD method.₆Gas and NH_ThreeA gas was used as a source gas. The reaction temperature was approximately 300 ° C. Further, the composition ratio of nitrogen was 20% so that the structure of tungsten nitride was amorphous.
0051]
  Next, in the process shown in FIG._FourThe tungsten nitride film, which is the sacrificial film 6, was etched back using a reaction gas composed of oxygen and oxygen. In this step, the tungsten nitride film formed on the side wall of the glass substrate 1 is formed thicker than 300 nm, and therefore remains as a side wall in the etch back step. The back etching time was controlled so that the side wall width at the bottom of the glass substrate pattern was 0.10 μm. As a result, the sidewall pattern 4 shown in FIG. 14 was left on the sidewall of the first pattern 3C in the step of etching back the sacrificial film 6.
0052]
  Next, in the process shown in FIG. 15, here, the light shielding film 20 made of chromium is applied to the DCPaIt was formed by the clutter method. The film thickness of the chromium film constituting the light shielding film 20 was 105 nm.
0053]
  Next, in the step shown in FIG. 16, an electron beam resist 7 was applied. In FIG. 8, symbols M and N indicate the second drawing scheduled area.
0054]
  In accordance with the second scheduled writing regions M and N shown in FIG. 17, these regions M and N were drawn with an electron beam having an acceleration voltage of 10 kV. The width of the pattern was 1.20 μm.
0055]
  Next, in the step of FIG. 17, the light shielding film 20 is etched and patterned using the patterned resist 7 formed by the electron beam drawing as a mask. Here, etching was performed by RIE using an etching gas composed of chlorine and oxygen to form a light shielding portion 2 having a predetermined pattern.
0056]
  The resist 7 was peeled off to obtain a phase shift mask having the structure of FIG. The width of the pattern formed in FIG. 10 was 1.20 μm between the sidewalls of pattern 3C, and the width of pattern D was 1.20 μm.
0057]
  The operation of the phase shift mask of this example will be described. In this embodiment, the sidewall 4 is made of tungsten nitride which is a light shielding material. Therefore, in the drawing step of FIG. 16, the drawing area (second drawing scheduled area M) corresponding to the light transmission area 3C (first pattern 3C) may be set larger than the distance between the sidewalls. . This is because the light shielding film 2 does not need to cover the sidewall pattern (the light shielding film 5 on the sidewall pattern in the first embodiment may be omitted). In addition, since the sidewall is formed of amorphous tungsten nitride, there is no edge roughness due to crystal grains as seen in a polycrystalline metal film.
0058]
  In this example, the sidewall pattern 4 is made of tungsten nitride, which is a light shielding material, and therefore does not cause diffraction of transmitted light on the side wall of the glass substrate 1 itself. For this reason, the so-called waveguide effect does not occur. The same light intensity as that of Embodiment 1 schematically shown in FIG. 2 can be obtained. Furthermore, the width of the sidewall 4 can be precisely controlled by the thickness of the sacrificial film 6 in the step of FIG. 13 and the etch back conditions in the step of FIG. For example, in the present embodiment, the sidewall width was 0.05 μm to 0.15 μm, and the mask pattern forming region could be formed with an accuracy of 3σ0.01.
0059]
  Further, the phase shift mask manufactured in this embodiment is subjected to ultrasonic cleaning for 10 minutes,TsuWhen a cleaning test was performed under conditions of 15 minutes for scrubbing and 10 minutes for scribing, in any case, peeling of the film or the like did not occur, and cleaning could be performed satisfactorily.
0060]
  As described above, the phase shift mask of the present example is a pattern transfer that does not cause a waveguide effect in the Levenson-type phase shift mask by forming a sidewall pattern, and thus does not have a non-uniform line width. Is possible. In addition, there is a degree of freedom in taking a drawing scheduled area in the second drawing process, and in some cases, positions in the first drawing process and the second drawing process are described in detail in the third embodiment. Even if a shift occurs, the effect is not impaired. And it has the advantage that it can wash | clean.
0061]
  Embodiment 3
  This embodiment is an embodiment of the same invention as the first and second embodiments. In this example, in the second drawing step, there is a positional deviation with respect to the first drawing step, the width of the first drawing region is 1.60 μm, and the sidewall width is 0.20 μm. This is the same as the second embodiment.
0062]
  That is, in the phase shift mask of this example, as shown in FIG. 18, the sidewall pattern 4 on the side wall of the first pattern 3E which is a light transmission region is made of a light shielding material (here, tungsten nitride is used). Although the waveguide effect is prevented or suppressed, in this example, even when there is a position shift, the position shift is absorbed in such a manner that the light shielding portion 2 is placed on the sidewall pattern 4.
0063]
  Hereinafter, the manufacturing process of the phase shift mask of this example will be described with reference to FIGS. As a process, the same procedure as in the second embodiment is taken.
  As shown in FIG. 19, the electron beam resist 1a was spin-coated on the glass substrate 1 so as to have a film thickness of 500 nm. On the electron beam resist 1a, an antistatic film 1b was formed. Next, in the step shown in FIG. 11, the resist 1 in the first drawing planned area I was drawn with an electron beam. Here, an electron beam acceleration voltage of 10 kV was used. The width of the pattern is 1.40 μm in the second embodiment, but is 1.60 μm here.
0064]
  Next, in the step shown in FIG._FourEtching was performed to a depth of 269 nm by reactive ion etching (RIE) using an etching gas composed of a gas. Thus, the first pattern 3C was formed by digging the glass substrate 1. Here, the depth of 269 nm is the same as in the second embodiment, and is the same reason as in the first embodiment, and the region 3E (region of the first pattern 3E) shown in FIG. The phase of light having a wavelength of 248 nm that passes through and the phase of light having a wavelength of 248 nm that passes through the region 3F (region of the second pattern 3F) are set to be 180 degrees different from each other.
0065]
  Next, in the step shown in FIG. 21, a tungsten nitride film to be the sacrificial film 6 was formed to a thickness of 300 nm. The tungsten nitride (WNx) film is formed by WF using the plasma CVD method.₆Gas and NH_ThreeA gas was used as a source gas. The reaction temperature was approximately 300 ° C. Further, the composition ratio of nitrogen was 20% so that the structure of tungsten nitride was amorphous.
0066]
  Next, in the process shown in FIG._FourThe tungsten nitride film, which is the sacrificial film 6, was etched back using a reaction gas composed of oxygen and oxygen. In this step, the tungsten nitride film formed on the side wall of the glass substrate 1 is formed thicker than 300 nm, and therefore remains as a side wall in the etch back step. The back etching time was controlled so that the width of the sidewall at the bottom of the glass substrate pattern was 0.20 μm in this example. As a result, the sidewall pattern 4 shown in FIG. 22 was left on the sidewall of the first pattern 3E in the step of etching back the sacrificial film 6.
0067]
  Next, in the step shown in FIG. 23, here, a light shielding film 20 made of chromium was formed by DC sputtering. The film thickness of the chromium film constituting the light shielding film 20 was 105 nm.
0068]
  Next, in the step shown in FIG. 24, an electron beam resist 7 was applied. In FIG. 8, symbols P and Q indicate the second drawing scheduled area. Here, the second drawing scheduled area P corresponding to the light transmission area E (first pattern E) is set larger than the distance between the sidewalls 4. Since the sidewall 4 in FIG. 18 is formed of a tungsten nitride film having a light shielding function, it is not necessary for the light shielding film 2 to cover the sidewall pattern as in the second embodiment (the side wall in the first embodiment). This is because the light shielding film 5 on the wall pattern may be omitted). That is, here, the width of the second drawing scheduled area P (corresponding to the first pattern E) is 1.40 μm, and the width of the second drawing scheduled area Q (corresponding to the second pattern F) is 1.20 μm. did. In addition, the drawing scheduled area P corresponding to the first pattern E, which is a light transmission area, is set so as to cover the center of the sidewall 4 in the second embodiment (see FIG. 16). In the process of FIG. 24, the case where the position shift of the magnitude | size of the half of side wall width has arisen is shown. Even in the case where such a positional deviation occurs, the sidewall 4 is formed of tungsten nitride, which is a light-shielding material here, so that the light transmission region E (first pattern E) in FIG. As shown, there is no waveguide effect.
0069]
  According to the second scheduled writing regions P and Q shown in FIG. 24, these regions P and Q are drawn with an electron beam having an acceleration voltage of 10 kV. The width of each pattern is as described above.
0070]
  Next, in the process of FIG. 25, the light shielding film 20 is etched using the patterned resist 7 formed by the electron beam drawing as a mask.PaTurned. Here, etching was performed by RIE using an etching gas composed of chlorine and oxygen to form a light shielding portion 2 having a predetermined pattern.
0071]
  Thereafter, the resist 7 was peeled off to obtain a phase shift mask according to this example having the structure of FIG. As described above, in this example, the drawing area is misaligned, but there is no problem in preventing the waveguide effect.
0072]
  In general, it is impossible to completely eliminate the misalignment of the second drawing process relative to the first drawing process, that is, a so-called overlay error. The overlay error usually occurs on the order of 0.06 μm. In this example, the sidewall width is 0.20 μm, and the drawing region is set to correspond to the center of the sidewall width, so even if there is an overlay error of at least 0.10 μm on one side. No problem. Actually, in this example, there was an overlay error of 3σ 0.063 μm on the entire mask surface, but the light transmission region E (first pattern E) could be formed without any problem.
0073]
  Further, the phase shift mask manufactured in this embodiment is subjected to ultrasonic cleaning for 10 minutes,TsuWhen a cleaning test was performed under conditions of 15 minutes for scrubbing and 10 minutes for scribing, in any case, peeling of the film or the like did not occur, and cleaning could be performed satisfactorily.
0074]
  As described above, the phase shift mask of the present example is a pattern transfer that does not cause a waveguide effect in the Levenson-type phase shift mask by forming a sidewall pattern, and thus does not have a non-uniform line width. Is possible. Further, there is an advantage that there is no problem even if a positional deviation occurs between the first drawing process and the second drawing process. And it has the advantage that it can wash | clean.
0075]
【The invention's effect】
  According to the present invention, the waveguide effect is satisfactorily eliminated or reduced for the phase shift mask.SetAnd this effect can be controlled without depending on the pattern size etc.sexIt is possible to provide a phase shift mask that can be obtained well and that can be variously cleaned, and a method for manufacturing the same.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing a phase shift mask according to a first embodiment.
FIG. 2 is a diagram for explaining the operation of the phase shift mask according to the first embodiment.
3 is a cross-sectional view showing the manufacturing process of Embodiment 1 in order (1). FIG.
FIG. 4 is a cross-sectional view sequentially showing manufacturing steps of Embodiment 1 (2).
FIG. 5 is a cross-sectional view sequentially showing the manufacturing process of the first embodiment (3).
6 is a sectional view sequentially showing the manufacturing process of the first embodiment (4). FIG.
FIG. 7 is a cross-sectional view sequentially showing manufacturing steps of Embodiment 1 (5).
FIG. 8 is a cross-sectional view sequentially showing the manufacturing process of the first embodiment (6).
FIG. 9 is a cross-sectional view sequentially showing the manufacturing process of the first embodiment (7).
10 is a schematic cross-sectional view showing a phase shift mask according to Embodiment 2. FIG.
FIG. 11 is a cross-sectional view sequentially showing manufacturing steps of Embodiment 2 (1)..
FIG. 12 is a cross-sectional view sequentially showing manufacturing steps of Embodiment 2 (2)..
FIG. 13 is a cross-sectional view sequentially showing manufacturing steps of Embodiment 2 (3)..
FIG. 14 is a cross-sectional view sequentially showing manufacturing steps of Embodiment 2 (4)..
FIG. 15 is a cross-sectional view showing the manufacturing process of Embodiment 2 in order (5)..
FIG. 16 is a cross-sectional view sequentially showing the manufacturing process of Embodiment 2 (6)..
FIG. 17 is a cross-sectional view sequentially showing the manufacturing process of the second embodiment (7)..
FIG. 18 is a schematic cross-sectional view showing a phase shift mask according to a third embodiment.
19 is a cross-sectional view showing the manufacturing process of Embodiment 3 in order (1). FIG..
FIG. 20 is a cross-sectional view sequentially showing the manufacturing process of Embodiment 3 (2)..
FIG. 21 is a cross-sectional view sequentially showing the manufacturing process of Embodiment 3 (3)..
FIG. 22 is a cross-sectional view sequentially showing the manufacturing process of Embodiment 3 (4)..
FIG. 23 is a cross-sectional view sequentially showing the manufacturing process of Embodiment 3 (5)..
FIG. 24 is a cross-sectional view showing the manufacturing process of Embodiment 3 in order (6)..
FIG. 25 is a cross-sectional view showing manufacturing steps of Embodiment 3 in order (7)..
[Figure26It is a diagram showing the prior art and its problems.
[Figure27It is a diagram showing the prior art and its problems.
[Figure28The manufacturing process of the prior art is shown in cross-sectional view in order..
[Figure29The manufacturing process of the prior art is shown in cross-sectional view in order..
[Figure30The manufacturing process of the prior art is shown in cross-sectional view in order..
[Figure31The manufacturing process of the prior art is shown in cross-sectional view in order..
[Figure32The manufacturing process of the prior art is shown in cross-sectional view in order..
[Figure33The manufacturing process of the prior art is shown in cross-sectional view in order..
[Figure34The manufacturing process of the prior art is shown in cross-sectional view in order..
[Explanation of symbols]
  DESCRIPTION OF SYMBOLS 1 ... Transparent base | substrate (glass base | substrate), 1a ... Electron beam resist, 1b ... Antistatic film, 2 ... Light-shielding part, 20 ... Light-shielding film,3A ... 1st pattern, 3B ... 2nd pattern, 4 ... Side wall-like pattern, 5 ... Shading film on side wall-like pattern, 6 ... Sacrificial film, ..Resist.

Claims (2)

A light-shielding portion made of a light-shielding film and a first pattern and a second pattern, which are light transmission patterns, are formed on a substrate transparent to exposure light, and the first pattern is formed by digging the substrate. In the phase shift mask, the phase of the light transmitted through the first pattern and the light transmitted through the second pattern is approximately 180 degrees different.
A sidewall pattern is formed on the sidewall of the first pattern,
The light shielding film on the first pattern side is formed so as to overlap the sidewall,
The light shielding film on the sidewall pattern or the sidewall pattern eliminates or reduces the waveguide effect,
The line width of the pattern transferred onto the exposed material by the light transmitted through the first pattern is substantially equal to the line width of the pattern transferred onto the exposed material by the light transmitted through the second pattern. A phase shift mask characterized by that. Forming a first pattern by digging a substrate transparent to exposure light, forming a sacrificial film, etching back the sacrificial film, and forming a light-shielding film on the substrate And a step of forming a second pattern on the light shielding film,
The phase of the light transmitted through the first pattern and the light transmitted through the second pattern is approximately 180 degrees different from each other.
On the side wall of the first pattern, a sacrificial film forming material remaining in the step of etching back the sacrificial film is formed in a sidewall shape.
The light shielding film on the first pattern side is formed so as to overlap at least a part of the sidewall;
The light shielding film on the side wall or side wall eliminates or reduces the waveguide effect,
The line width of the pattern transferred onto the exposed material by the light transmitted through the first pattern is substantially equal to the line width of the pattern transferred onto the exposed material by the light transmitted through the second pattern. A method of manufacturing a phase shift mask, comprising: forming a mask as follows.

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