JP2005123337A - Transfer mask for charged particle beam and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stencil mask which is used for the EPL system and LEEPL system using the electron beam as the light source to reduce influence on the quality to the pattern, accurately detect the location accuracy of pattern to be transferred within the transfer region and is given the IP mark ensured; and also to provide the manufacturing method thereof. <P>SOLUTION: In the transfer mask for the charged particles of the stencil mask structure, a pattern to be transferred to a membrane formed of an absorbing material for absorbing the charged particle beam or of a scattering material for scattering the charged particle beam is formed in the shape of opening. Moreover, an additional pattern other than the pattern explained above is also formed. This additional pattern has a size equal to or larger than the transfer resolution limit within the transfer region and is not transferred. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to charged particle beam transfer masks for electron projection lithography EPL (Electron-Beam Projection Lithography), low-energy electron proximity projection lithography LEEPL (Low Energy Electron-Beam Proximity Projection Lithography), and the like.

  In recent years, there is a strong demand for higher integration of semiconductor device circuits, and the next generation lithography (NGL: Next Generation Lithography), which is currently used for mass production, is an electron beam or soft X-ray (EUV: Extremely Ultra). Research and development of lithography using violet or the like as a light source has been actively conducted.

As the light source using an electron beam, as shown in FIG. 9, an EPL method in which a mask pattern is reduced and projected onto a wafer using a high energy electron beam having an acceleration voltage of about 100 kV, or as shown in FIG. The LEEPL method, in which a mask pattern is closely exposed at the same magnification using a low energy electron beam with an acceleration voltage of about 2 kV, has been developed and studied.
The EPL method is different from the scanning method of the electron beam due to the difference in the PREVAIL (Proposition Exposure with Variable Axis Immersion Lens) method (HCC Pfeiffer, Journal of Vaccum Science 19 and A40. LR Herriott, Journal of Vaccum Science and Technology B15 p.2130 (1997)), but it is common to adopt a scatterer membrane as described later.
Journal of Vaccum Science and Technology B17 p. 2840 (1999) Journal of Vaccum Science and Technology B15 p. 2130 (1997) The LEEPL system is a low-speed electron beam proximity projection transfer system proposed by Utsumi (T. Utsumi, Journal of Vaccum Science and Technology B17 p. 2897 (1999)). Journal of Vaccum Science and Technology B17 p. 2897 (1999) In the EPL system, a circuit pattern is arranged on a number of divided small areas (hereinafter referred to as subfields) on a mask. Incidentally, the size of the subfield is a square of 1 mm × 1 mm in the PREVAIL system, and a square meter of 1 mm × 12 mm in the SCALPEL system. In the EPL method, a square electron beam of 1 mm × 1 mm is irradiated, and subfields are collectively transferred in the PREVAIL method, and transferred in one direction in the SCALPEL method. Further, in the case of the LEEPL method, FIG. As shown in FIG. 5, the direction (angle and azimuth) of the electron beam incident on the mask opening can be adjusted by using a two-stage sub-deflector. This function makes it possible to correct the transfer position on the wafer. As shown in FIG. 12, the position error (also referred to as IP error) is smaller in the case with correction (FIG. 12B) than in the case without correction (FIG. 12A). In order to use this function, it is necessary to know in advance the position error of the mark corresponding to the lattice point, which is the design position on the mask (1220 in Fig. 12). In the case of the EPL method, as shown in FIG. 9, the electrons that have passed through the opening 612 of the membrane 611 pass through the opening 641 of the aperture 640 to form an image. Although electrons that have passed through the non-opening portion 613 of the membrane 611 are scattered by the membrane that is a scatterer, most of the electrons can pass through the opening 641 of the aperture 640. In the case of the LEEPL system, as shown in Fig. 10, the gap G between the membrane 711 and the resist 780 is brought close to 30 µm to 90 µm, and scanning is performed while irradiating an electron beam 720 having a predetermined spot diameter. Therefore, the electron beam irradiated to the non-opening portion 713 of the membrane 711 is absorbed by the membrane 711 which is an absorber, and does not contribute to image formation, and only the electron beam irradiated to the opening portion 712 of the membrane 711 is an image. Contribute to formation

The mask used here is called a stencil mask, and a thin membrane made of silicon, diamond or the like is used as an electron beam absorbing layer or a scattering layer, and a pattern is formed by punching it.
Conventionally, in such a stencil mask, there is no accurate position management method for the pattern in the transfer region, and its correspondence has been demanded.
For example, as shown in FIG. 14, a method of arranging the mark pattern 831 outside the transfer area 820 has been adopted, but with this, it is impossible to accurately grasp the positional accuracy of the main pattern in the transfer area. .
Conventionally, when a mark is inserted into a transfer area, the mark is also transferred. Therefore, insertion of a mark is allowed only when there is no problem even if transferred, and generally not allowed.
In addition, since it is not preferable that the mark pattern is transferred at the time of transfer, as shown in FIG. 15, in the transfer area 910, a missing figure or the like may be formed to a size smaller than the transfer resolution as in this pattern. However, in this case, there is a problem in that accurate mark detection cannot be performed due to the quality influence on the main pattern and the fine mark pattern 930.
Normally, considering that the position of the mask pattern is measured by a reflection type measuring instrument, it is preferable that the mask pattern can be measured by a reflection type measuring instrument and is not transferred.
Furthermore, it is required that the pattern transfer characteristics (particularly shape and position) of this pattern are not affected.
JP 2003-59819 A Japanese Patent Laid-Open No. 10-10706

As described above, in the conventional stencil masks used for the EPL method and the LEEPL method using an electron beam as a light source, the quality of the main pattern is less affected, and the position of the main pattern to be transferred in the transfer region. None of them were equipped with a position measurement mark (hereinafter also referred to as an IP mark) that can accurately ascertain and guarantee accuracy, and there was a need to deal with it.
The present invention corresponds to this, and is a stencil mask used in an EPL method or a LEEPL method using an electron beam as a light source, has little influence on the quality of the pattern, and transfers in the transfer region. The present invention intends to provide a mark with a position measurement mark (IP mark) that can accurately ascertain and guarantee the position accuracy of the power pattern.
Thus, it is intended to make it possible to correct the position error of the main pattern of the stencil mask to be used when transferring.

The charged particle beam transfer mask of the present invention has a stencil mask structure in which the main pattern to be transferred is formed on a membrane composed of an absorber for absorbing the charged particle beam or a scatterer for scattering the charged particle beam. The particle beam transfer mask is characterized in that an additional pattern other than the main pattern is formed in the transfer region, which has a dimension equal to or greater than a transfer resolution limit and is not transferred.
In the charged particle beam transfer mask, the additional pattern is a reflective pattern for recognition by a detection method in which at least one of light, an electron beam, and an ion beam is irradiated and detected. It is characterized by this.
In addition, in the transfer mask for charged particle beam according to any one of the above, the additional pattern is formed by digging a recess in the membrane.
Alternatively, in any one of the above-described transfer masks for charged particle beams, the additional pattern is formed by adding the formation layer on the membrane. Is made of CrxNy or SiO ₂ .

  In addition, any one of the above-described transfer masks for charged particle beams, wherein the additional pattern is a position measurement mark (IP mark), and the additional pattern overlaps the pattern of this pattern. It is characterized by being.

In addition, any one of the above-described transfer masks for charged particle beams is characterized by being used for low-energy electron beam proximity projection lithography LEEPL (Low Energy Electron-Beam Proximity Projection Lithography).
Alternatively, any one of the above-described transfer masks for charged particle beams is characterized by being used for electron projection lithography EPL (Electron-Beam Projection Lithography).

The position measurement mark (hereinafter also referred to as IP mark) is a mark for grasping, managing, or guaranteeing the position accuracy of the pattern, and the stencil structure used in EPL and LEEPL using an electron beam. A position measurement mark (IP mark) is added to the mask of the pattern, and the data obtained by measuring the position of the IP mark is used to correct the position error of this pattern (this is also called an IP error). It can be performed.
IP is an abbreviation for Image Placement.
The stencil mask structure is a structure in which the membrane is penetrated in a pattern shape so that it can be transferred, or as shown in FIG.
As the ultrathin film, a carbon-based material having a thickness of 5 nm to 80 nm is used.

The method for producing a transfer mask for charged particle beam according to the present invention comprises a stencil mask in which the pattern to be transferred is formed on a membrane comprising an absorber for absorbing charged particle beam or a scatterer for scattering charged particle beam. A charged particle beam transfer mask having a structure is formed by adding an additional pattern other than the main pattern in the transfer region and the formation layer on the membrane. A method for manufacturing a transfer mask for charged particle beam, in order to (a) sequentially create a pattern for forming an additional pattern and a main pattern on one surface of a membrane material for forming the main pattern A mask layer disposing step of disposing a mask layer for forming a mask that also serves as the mask of (b), and (b) the shape of the additional pattern and the main pattern on the mask layer A first resist plate-making process for forming a first resist pattern in a predetermined shape including, and (c) etching the mask layer using the first resist pattern as an anti-etching mask and penetrating the first resist pattern shape A first etching step for forming a hole; (d) a first resist removal step for removing the first resist pattern; and (e) a second region so as to cover only a predetermined region including the additional pattern region. A second plate-making process for forming a resist pattern; and (f) a second pattern forming the pattern by etching the membrane material using the second resist pattern and the mask layer in which the through holes are formed as an anti-etching mask. An etching process, (g) a mask layer removing process for removing a region of the mask layer not covered with the second resist pattern, and (h) a second resist. A second resist removal step of removing the pattern, it is characterized in that to perform.
In the method for manufacturing the above-mentioned transfer mask for charged particle beam, the mask layer is multilayered, and only the lower layer is left after the second resist removing step, and the upper layer is removed.

Alternatively, in the method for manufacturing a transfer mask for charged particle beam according to the present invention, an opening is formed in the pattern to be transferred to a membrane composed of an absorber for absorbing the charged particle beam or a scatterer for scattering the charged particle beam. A charged particle beam transfer mask having a stencil mask structure, which is formed by digging a recess in the membrane without adding an additional pattern other than the main pattern in the transfer region. In order to produce a transfer mask for charged particle beam, (a1) A mask for forming an additional pattern and a main pattern are formed on one surface of a membrane material for forming the main pattern. A mask layer disposing step of disposing a mask layer for forming a mask that also serves as a mask for performing (b1) an additional pattern on the mask layer; (C1) etching the mask layer using the first resist pattern as an anti-etching mask, and forming the first resist pattern in a predetermined shape including the shape of the pattern and the main pattern; (D1) a first resist removing step for removing the first resist pattern, and (e1) covering only a predetermined region including the additional pattern region. Thus, the second plate making process for forming the second resist pattern, and (f1) etching the membrane material and the second resist pattern using the mask layer in which the through hole is formed as an etching resistant mask, And a second etching step for forming an additional pattern by digging without penetrating the membrane material, and (g1) mask The mask layer removing step of removing, and is characterized in that to perform.
A method for manufacturing the above-described transfer mask for charged particle beam, wherein the thickness of the membrane made of the scattering layer material or the absorption layer material, the thickness of the second resist pattern, and the depth of the recess are respectively L, When S and H are set, and the etching rate of the membrane material is A and the etching rate of the second resist pattern is B, when f is an overetch factor (constant) of the membrane material,
(S / B) + (H / A) = f (L / A)
Thus, S = (fL−H) / (A / B) is obtained, and the process factors f and (A / B) are determined to determine the thickness S of the second resist pattern. It is characterized by being.
Alternatively, in the method for manufacturing a transfer mask for charged particle beam according to the present invention, an opening is formed in the pattern to be transferred to a membrane composed of an absorber for absorbing the charged particle beam or a scatterer for scattering the charged particle beam. A charged particle beam transfer mask having a stencil mask structure and formed by digging a concave portion in the membrane with an additional pattern other than the main pattern overlapped with the main pattern in the transfer region. In order, (a2) a resist pattern having an opening in the shape of the main pattern is added to one surface of the membrane material for forming the main pattern. A resist plate-making process in which only the pattern formation region is thinned, and (b2) the resist pattern and the membrane in which the opening is formed Etching to remove only the resist pattern in the additional pattern formation region and leave the resist pattern in other regions to form this pattern, and to dig without penetrating the membrane material to form the additional pattern And (c2) a resist layer removing step for removing the resist pattern.

Note that f = 1 is when the etching of the membrane material is just etching, and f> 1 is when overetching.
When A / B = C, C is called an etching selectivity of the membrane material to the second resist.

(Function)
The charged particle beam transfer mask of the present invention is a stencil mask used in an EPL method or a LEEPL method using an electron beam as a light source by having the above-described configuration, and has a quality influence on the pattern. It is possible to provide an IP mark with an IP mark that can accurately ascertain and guarantee the position accuracy of the main pattern to be transferred in the transfer area, and is used when transferring using this. The position error of the main pattern of the stencil mask can be corrected effectively.
Specifically, this is achieved by having a structure in the transfer region that has a dimension that is equal to or greater than the transfer resolution limit and that has an additional pattern other than the main pattern that is not transferred.
As the additional pattern, a reflective pattern for recognizing by a detection method of irradiating and detecting at least one of light, electron beam, and ion beam is preferably used.
In this case, it can be measured by a conventional reflection type measuring instrument or the same method.
In the case of a reflection type pattern measured by such a reflection type measuring instrument, the intensity of the reflected or scattered light, electron beam, ion beam, etc. is detected from the additional pattern, and the detected intensity change From this, the position of the additional pattern can be grasped.
The additional pattern as the IP mark is used to accurately grasp the position of the main pattern corresponding to the additional pattern by grasping the position of the additional pattern, and the additional pattern and the main pattern are predetermined positions to be managed. It is premised that it is formed within accuracy.
And as a form of an additional pattern, the thing formed by digging a recessed part in a membrane, or the thing formed by adding the formation layer on a membrane is mentioned.
The formation layer is controlled to have a predetermined thickness of CrxNy or SiO ₂ on the premise that the layer is not transferred and does not adversely affect the quality of this pattern.

The method for producing a transfer mask for charged particle beam according to the present invention has the above-described configuration, so that the position of the pattern in the transfer region is a stencil mask used in an EPL method or a LEEPL method using an electron beam as a light source. It is possible to provide a method for manufacturing a transfer mask for charged particle beam that can be managed accurately.
A charged particle beam transfer having a stencil mask structure in which the pattern to be transferred is formed on a membrane comprising an absorber for absorbing charged particle beams or a scatterer for scattering charged particle beams according to claim 10. Charged particle beam for producing a transfer mask for charged particle beam, which is formed by adding an additional pattern other than the main pattern in the transfer region and a formation layer on the membrane with a mask. In the case of the transfer mask manufacturing method, by making the mask layer as a multilayer of two or more layers, it is possible to create a thin additional pattern by leaving only the lower layer after the second resist removing step and removing the upper layer. Yes.
As a result, the influence on the pattern transfer characteristics (particularly the shape and position) of this pattern can be reduced.
Of course, it is preferable that the upper layer has resistance to etching for forming this pattern and can be easily removed.
13. A charged particle beam transfer having a stencil mask structure in which the pattern to be transferred is formed on a membrane comprising an absorber for absorbing a charged particle beam or a scatterer for scattering a charged particle beam according to claim 12. A charged particle beam transfer mask manufacturing method for manufacturing a charged particle beam transfer mask formed by digging a concave portion in a membrane with an additional pattern other than the main pattern in a transfer region in a transfer region In this case, the thickness of the membrane made of the scattering layer material or the absorption layer material, the thickness of the second resist pattern, and the depth of the recess are L, S, and H, respectively, and the etching rate of the membrane material is A and second. When the etching rate of the resist pattern is B, and f is the overetch factor (constant) of the membrane material,
(S / B) + (H / A) = f (L / A)
Thus, S = (fL−H) / (A / B) is obtained, and the process factors f and (A / B) are determined to determine the thickness S of the second resist pattern. Can do.
Note that f = 1 is when the etching of the membrane material is just etching, and f> 1 is when overetching.
When A / B = C, C is called an etching selectivity of the membrane material to the second resist.

As described above, the present invention is a stencil mask used in an EPL method or a LEEPL method using an electron beam, has little influence on the quality of the pattern, and the pattern of the pattern to be transferred in the transfer region. We have made it possible to provide products with an IP mark that can accurately ascertain and guarantee position accuracy.
This makes it possible to effectively correct the position error of the main pattern of the stencil mask used when transferring using this.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1A is a schematic plan view of a part of a first example of an embodiment of the transfer mask for charged particle beam according to the present invention, and FIG. 1B is a cross-sectional view taken along line A1-A2 of FIG. 2 is a partial cross-sectional view of a second example of the embodiment of the transfer mask for charged particle beam according to the present invention. FIGS. 3A and 3B are respectively IP diagrams. FIG. 4A to FIG. 4H are cross-sectional views of manufacturing steps of the charged particle beam transfer mask of the first example shown in FIG. 1, and FIG. 5A to FIG. 5 (g) is a cross-sectional view of the manufacturing process of the charged particle beam transfer mask of the second example shown in FIG. 2, and FIG. 6 is a condition for forming the recess when manufacturing the charged mask of the charged particle beam of the second example. FIG. 7A is a schematic plan view of a part of the third example of the embodiment of the transfer mask for charged particle beam according to the present invention, and FIG. a) in the transcription region FIG. 7C is a cross-sectional view taken along line C1-C2 of FIG. 7B, and FIGS. 8A to 8E are third views shown in FIG. It is manufacturing process sectional drawing of the transfer mask for charged particle beams of the example of.
Incidentally, the IP mark 32 part of FIG. 1B shows a cross section taken along B1-B2 of FIG. 1 to 8, 10 is a transfer area, 20 is a main pattern area, 21 is a membrane, 21A is an opening (also referred to as a through hole), 25 is a missing figure (through figure) of this pattern, and 29 is a book to be evaluated. Pattern graphics 30, 31, 31a, 32, and 32a are IP marks (position measurement marks), 35 is an IP mark material, 36 is an opening, 38 is a recess, 40 is another pattern prohibited area, and 50 is an IP mark (position). 50A is an IP mark area, 51 is an outline of the IP mark area, 60 is a membrane, 110 is a mask layer material, 110A is a mask (also referred to as an intermediate mask), and 110B is a mark pattern (IP mark). , 115 is an opening, 120 is a membrane, 125 is an opening (also referred to as a through hole), 130 is a first resist pattern, 135 is an opening, and 137 is a second resist. , 210 is a mask layer material, 210A is a mask (also referred to as an intermediate mask), 215 is an opening, 220 is a membrane, 225 is an opening (also referred to as a through hole), 230 is a first resist pattern, 235 is an opening, and 237 is an opening Second resist pattern, 250 is a recess, 310 is a membrane material, 315 is an opening, 320 is a resist, 320A and 320B are resist patterns, 325 is an opening, 330 and 355 are exposure light, and 340 is an exposure area of the second exposure , 350 is an IP formation region.

First, a first example of an embodiment of a charged particle beam transfer mask of the present invention will be described with reference to FIG.
The charged particle beam transfer mask of the first example is for a LEEPL type electron beam having a stencil mask structure in which a main pattern to be transferred to an membrane 21 made of an absorber for absorbing an electron beam is formed with an opening 21A. It is a transfer mask.
An IP mark 30 having a dimension not less than the transfer resolution limit and not transferred in the transfer region 10 is formed as an additional pattern other than the main pattern.
The IP mark 30 is formed by adding an IP mark material 35 as a formation layer on the membrane 21, and is formed without overlapping the pattern of this pattern.
The IP mark 30 used in this example has a cross pattern formed as the opening 36 of the IP mark material 35 shown in FIG.

The IP mark 30 in the first example is used in an optical detection method for detecting a reflected or scattered light intensity by irradiating a predetermined laser beam as detection light and irradiating it. This is a pattern for recognizing a stepped portion by a method and thereby grasping a mark position.
For example, using a commercially available optical measuring instrument (Leica, LMS IPRO), a predetermined laser beam is scanned in the X direction or Y direction at a predetermined position (mark position), and two mark ends in each direction. The mark position is obtained by detecting the position of the step.
In this way, the positions of the plurality of IP marks are measured by the optical measuring device, the deviation from the design value is grasped, and the electron beam is irradiated while correcting the deviation at the time of transfer.
The positional deviation of the IP mark represents a distortion from the design value of the main pattern. After all, the distortion of the main pattern is corrected by such correction.
The mark shape is not particularly limited, but there is a limit to the region where it is formed.
A cross pattern is formed as the opening 36 of the IP mark material 35 shown in FIG. 3A used in this example, or a cross pattern is formed with the IP mark material 35 as shown in FIG. 3B. Furthermore, in place of these cross-shaped patterns, those formed with an L-shaped pattern can be used.
In FIG. 3, the other pattern prohibited area 40 is an area where the mark position cannot be accurately detected when there is another pattern in this area.

In this example, a 1 μm-thick Si layer was used as the membrane 21, but other materials may be used as long as they can be applied in consideration of properties as a mask material, chemical resistance, and the like. In addition, although 0.1 μm-thick CrOxNy is used here as the IP mark material 35, it is required not to transfer or to have no influence on the quality value of this pattern.
Examples of the other IP mark material 35 include SiO ₂ .
In the LEEPL system, an electron beam acceleration voltage of 2 kV is normally used. When the membrane 21 is Si, the penetration depth of electrons into the membrane 21 is about 0.1 μm, and therefore the membrane as an absorber. It is sufficient that the thickness of 21 is 0.2 μm or more multiplied by a margin factor of about twice the factor.
In addition, the membrane 21 is required to have chemical resistance and the like for its production process, and to have low stress.
The thickness of the membrane 21 as an absorber is preferably large in order to increase the strength of the self-supporting film. In addition, when forming a stencil-structured pattern, the pattern aspect ratio ( In response to the conflicting requirement that smaller (Aspect Ratio) is preferable, in the case of Si, the thickness is set to 0.5 μm to 1.0 μm.
However, with respect to some of the main patterns (fine patterns as in the example of FIG. 7), it may be accepted that accuracy is slightly lowered, and the restriction on prohibition of other patterns may be released.

Next, an example of the manufacturing method of the charged particle beam transfer mask of the first example will be described with reference to FIG.
This replaces the example of the embodiment of the method for manufacturing the transfer mask for charged particle beam according to the present invention.
First, on one surface of the membrane material 120 for forming this pattern, a mask layer 110 for forming a pattern for forming an IP mark as an additional pattern and a mask serving as a mask for creating this pattern is arranged. Set it up. (Fig. 4 (a))
Here, a Si layer having a thickness of 2 μm is used as the membrane 120, and CrOxNy having a thickness of 0.05 μm to 0.4 μm is used as the mask layer 110.
Next, a first resist pattern 130 is formed on the mask layer 110 in a predetermined shape including the shape of the IP mark and this pattern. (Fig. 4 (b))
The first resist pattern 130 is not particularly limited as long as it has desired resolution and good processability.
The exposure for creating the IP mark and the resist pattern 130 for patterning this pattern is performed simultaneously in the same process.
This is a necessary condition for accurately obtaining the positional relationship between the IP mark and this pattern. Next, using the first resist pattern 130 as an anti-etching mask, the mask layer 110 is etched to form a through hole having a first resist pattern shape. (Fig. 4 (c))
Etching is performed by dry etching using a Cl-based gas (Cl ₂ + O ₂ ).
Next, after removing the first resist pattern 130 (FIG. 4D), a second region is formed so as to cover only a predetermined region including the IP mark formation region (corresponding to the other pattern prohibited region 40 in FIG. 3). A resist pattern 137 is formed. (Fig. 4 (e))
The second resist pattern 137 is not particularly limited as long as it has a desired resolution and a good processability.
Next, the membrane material 120 is etched using the second resist pattern 137 and the mask 110A which is a mask layer in which the through hole is formed as an anti-etching mask to form this pattern. (Fig. 4 (f))
Etching of the membrane material 120 made of Si is performed by dry etching using SF ₆ + CHF ₃ gas.
Next, the region of the mask layer 130 that is not covered with the second resist pattern 137 is removed. (Fig. 4 (g))
This removal is performed using a commercially available chromium etching solution.
Thereafter, the second resist pattern 137 is removed, and a predetermined cleaning or the like is performed to obtain a charged particle beam transfer mask of the first example. (Fig. 4 (h))
Thus, the charged particle beam transfer mask of the first example can be manufactured.
By adopting such a manufacturing method, the positional relationship between the IP mark and this pattern can be accurately taken.

Next, a second example of the charged particle beam transfer mask of the present invention will be described with reference to FIG.
Similarly to the first example, the charged particle beam transfer mask of the second example also has a stencil mask structure in which this pattern to be transferred to the membrane 21 made of an absorber for absorbing an electron beam is formed with an opening 21A. , LEEPL type electron beam transfer mask.
The IP marks 31a and 32a in the second example are formed by digging the recesses 38 in the membrane 21, and other than this is the same as the first example, and the description is omitted.

Next, an example of the manufacturing method of the charged particle beam transfer mask of the second example will be described with reference to FIG.
This replaces the example of the embodiment of the method for manufacturing the transfer mask for charged particle beam according to the present invention.
First, in the same way as the manufacturing method of the charged particle beam transfer mask of the first example shown in FIG.
On one surface of the membrane material 220 for forming this pattern, a mask layer 210 for forming a mask that also serves as a mask for forming an IP mark as an additional pattern and a mask for creating this pattern is disposed. (FIG. 5 (a)),
After the first resist pattern 230 is formed on the mask layer 210 in a predetermined shape including the shape of the IP mark and the main pattern (FIG. 5B), the first resist pattern 230 is used as an etching resistant mask. The layer 210 is etched to form through holes having a first resist pattern shape (FIG. 5C), and the first resist pattern 230 is removed. (FIG. 5D) The material of each part and the processing conditions are the same as those in the manufacturing method of the charged particle beam transfer mask of the first example shown in FIG.
Next, a second resist pattern 237 is formed so as to cover only a predetermined region including the IP pattern region (FIG. 5E), and the membrane material is formed using the mask layer 210 in which the through hole is formed as an etching resistant mask. 220 and the second resist pattern 237 are etched to form this pattern, and a concave portion 250 is formed without penetrating the membrane material 220 to form an IP pattern made of the concave portion. (Fig. 5 (f))
The second resist pattern 237 also has a desired resolution and good processability, and further, here, it is necessary to remove the second resist pattern 237 with the membrane material 220 with the same etchant with a predetermined selectivity. is there.
For this etching, dry etching using SF ₆ + CHF ₃ gas is employed. The selection ratio is adjusted according to dry etching conditions (gas flow rate ratio, substrate bias voltage, input power) and the like.
Next, the mask layer 210 (mask 210A) is removed, and after a predetermined cleaning or the like, a second example of a charged particle beam transfer mask is obtained. (Fig. 5 (g))
In this way, the charged particle beam transfer mask of the second example can be manufactured.
By adopting such a manufacturing method, the positional relationship between the IP mark and this pattern can be accurately taken.

A method of determining the conditions for forming the recess 250 at a predetermined depth in the manufacturing method shown in FIG. 4 will be briefly described with reference to FIG.
The thickness of the membrane material 220, the thickness of the second resist pattern 237 in the recess formation region, and the depth of the recess are L, S, and H, respectively, the etching rate of the membrane material 220 is A, and the second resist pattern When the etching rate of B is B, when f is the overetch factor (constant) of the membrane material,
(S / B) + (H / A) = f (L / A)
The etching selectivity C of the membrane material to the second resist is expressed by (A / B).
Than this,
S = (fL−H) / (A / B) = (fL−H) / C
However, by determining f and C, which are process factors, and determining the thickness S of the second resist pattern, the recess 250 can be formed to a desired depth.
FIG. 6 is a diagram when the overetch factor (constant) f is equal to or greater than 1. Moreover, as H, the thickness which only absorbs an electron is required.
Furthermore, since the IP mark detection function does not depend strongly on the deviation of H from the target value, the required accuracy for S may be low.

Next, a third example of the embodiment of the transfer mask for charged particle beam according to the present invention will be described with reference to FIG.
Similarly to the first example, the charged particle beam transfer mask of the third example also has a stencil mask structure in which the main pattern to be transferred to the membrane 60 made of an absorber for absorbing an electron beam is formed with an opening 25. , LEEPL type electron beam transfer mask. As in the first example, as shown in FIG. 7A, the IP mark 50 is in the present pattern area. In the third example, as shown in FIG. 7B, The IP mark 50 is formed so as to overlap the pattern of the main pattern in the transfer region, and the main pattern portion of the membrane 60 is formed in a thin shape in the shape of the IP mark 50.
The IP mark region 50A corresponds to the thin region of the membrane 60 shown in FIG. Other than this, it is the same as the first example and will not be described.

Here, the manufacturing method of the charged particle beam transfer mask of the third example will be briefly described with reference to FIG.
After the positive resist 320 is applied to the membrane material 310, first exposure is performed to expose the opening (315 in FIG. 5E) formation region of this pattern with a predetermined intensity. (Fig. 8 (a))
The first exposure is performed with a light intensity that allows the resist in the region corresponding to the opening of the pattern to pass through after development.
Next, a second exposure is performed to expose the resist portion corresponding to the IP mark formation region (350 in FIG. 8E). (Fig. 8 (b))
More specifically, the condition that the sum of the light intensity of the first exposure and the light intensity of the second exposure is equal to the main pattern inside and outside the IP mark formation region is imposed from the viewpoint of dimensional control of the main pattern. Therefore, in the first exposure, it is preferable and technically possible to reduce the light intensity of the main pattern in the IP mark formation region so as to satisfy the above condition.
Here, it is assumed that both the first exposure and the second exposure for creating the resist pattern 320 for patterning the IP mark and this pattern are performed accurately under the same position management control. It becomes.
This is exposure for thinning the resist 320 in this region in order to thin the membrane 310 of the main pattern in the IP mark formation region 340 after development. Next, development is performed to penetrate the region corresponding to the opening of this pattern, and the resist 320 in the IP mark formation region is thinned. (Fig. 8 (c))
Next, the resist 320A and the membrane material 310 are etched to form an opening 315 for forming a phone pattern, and a thin region for forming an IP pattern. (Fig. 8 (d))
Etching of the membrane material 310 is stopped in a state in which a thin IP mark is formed and a resist remains in a portion other than the thin portion.
Next, the remaining resist is removed to obtain a charged particle beam transfer mask of the third example. (Fig. 8 (e))
Thus, the charged particle beam transfer mask of the third example can be manufactured.
By adopting such a manufacturing method, the positional relationship between the IP mark and this pattern can be accurately taken.

The first to third examples are LEEPL type charged particle beam transfer masks, but structures similar to these can also be applied to EPL type charged particle beam transfer masks.
For example, in the first example, the thickness of the material Si of the membrane 21 is increased to about 2 μm, CrOxNy is set to about 0.05 μm to 0.4 μm, and this structure can be applied to the EPL system. .
Of course, as a modified example of the transfer mask for charged particle beam of each of the above forms, there is a form in which the pattern part of this pattern is completely penetrated and supported by an extremely thin film as shown in FIG. .

FIG. 1A is a schematic plan view of a part of the first example of the embodiment of the transfer mask for charged particle beam according to the present invention, and FIG. It is sectional drawing which showed. It is a partial cross section figure of the 2nd example of embodiment of the transfer mask for charged particle beams of this invention. 3A and 3B are diagrams showing examples of IP marks. FIG. 4A to FIG. 4H are sectional views of manufacturing steps of the charged particle beam transfer mask of the first example shown in FIG. FIG. 5A to FIG. 5G are sectional views of manufacturing steps of the charged particle beam transfer mask of the second example shown in FIG. It is a figure for demonstrating the formation conditions of the recessed part at the time of manufacturing the transfer mask for charged particle beams of a 2nd example. FIG. 7A is a schematic plan view of a part of the third example of the embodiment of the transfer mask for charged particle beam according to the present invention, and FIG. 7B shows the IP in the transfer region of FIG. FIG. 7C is an enlarged view of the mark 50, and FIG. 7C is a cross-sectional view taken along line C1-C2 of FIG. 7B. FIG. 8A to FIG. 8E are sectional views of manufacturing processes of the charged particle beam transfer mask of the third example shown in FIG. It is a figure for demonstrating the exposure in an EPL system. It is a figure for demonstrating the exposure in a LEEPL system. It is a figure for demonstrating the transfer position correction | amendment operation | movement in a LEEPL apparatus. FIG. 13A shows a pattern position without correction, and FIG. 13B shows a pattern position with correction. It is the figure which showed the structure of the stencil mask which has an ultra-thin film for membrane support. It is a figure for demonstrating the example of arrangement | positioning of the conventional mark pattern. It is a figure for demonstrating the example of arrangement | positioning of the other conventional mark pattern.

Explanation of symbols

10 Transfer area 20 Main pattern area 21 Membrane 21A Opening (also referred to as through hole)
25 missing pattern (penetrating figure)
29 This pattern figure 30, 31, 31a, 32, 32a to be evaluated IP mark (referred to as a position measurement mark)
35 IP mark material 36 Opening 38 Recess 40 Other pattern prohibited area 50 IP mark (position measurement mark)
50A IP mark region 51 Outline of IP mark region 60 Membrane 110 Mask layer material 110A Mask (also referred to as intermediate mask)
110B Mark pattern (IP mark)
115 opening 120 membrane 125 opening (also called through hole)
130 First resist pattern 135 Opening 137 Second resist pattern 210 Mask layer material 210A Mask (also referred to as intermediate mask)
215 Opening 220 Membrane 225 Opening (also called through hole)
230 First resist pattern 235 Opening 237 Second resist pattern 250 Recess 310 Membrane material 315 Opening 320 Resist 320A, 320B Resist pattern 325 Opening 330, 335 Exposure light 340 Second exposure exposure area 350 IP formation area 610 EPL mask (Stencil mask for EPL system)
611 membrane (scatterer)
612 Opening 613 Non-opening 620 Electron beam 621 Image forming electron 625 Scattered electron beam 630, 635 Projection lens system 640 Aperture 641 Opening 650 Wafer 660 Resist 710 LEEPL mask (Stencil mask for LEEPL system)
711 membrane (absorber)
712 Opening 713 Non-opening 715 Supporting part 720 (Spot-shaped) electron beam 750 Wafer 760 Resist 810 Membrane 815 Beam 820 Transfer area 830, 831 Mark pattern 910 This pattern area 920 This pattern (missing figure)
930 Mark pattern (missing figure) (with dimensions below transfer resolution)
1110 Electron gun 1120 Lens 1130 Aperture 1140, 1145 Main deflector 1150, 1155 Sub deflector 1160 Stencil mask 1170 Resist coated wafer 1180 Position correction amount 1210 Pattern position 1220 Design position (lattice point)
1230 Design lattice 1310 Membrane 1315 Through hole

Claims (14)

  A transfer mask for a charged particle beam having a stencil mask structure in which this pattern to be transferred is formed on a membrane comprising an absorber for absorbing a charged particle beam or a scatterer for scattering a charged particle beam. A charged particle beam transfer mask characterized in that an additional pattern other than the main pattern, which has a dimension exceeding the transfer resolution limit and is not transferred, is formed therein.   2. The charged particle beam transfer mask according to claim 1, wherein the additional pattern is a reflective pattern for recognition by a detection method in which at least one of light, an electron beam, and an ion beam is irradiated and detected. A charged particle beam transfer mask characterized by the above.   3. The charged particle beam transfer mask according to claim 1, wherein the additional pattern is formed by digging a recess in the membrane. 4.   The charged particle beam transfer mask according to claim 1, wherein the additional pattern is formed by adding a formation layer on the membrane. Transfer mask. The charged particle beam transfer mask according to claim 4, wherein the formation layer is made of CrxNy or SiO ₂ .   6. The charged particle beam transfer mask according to claim 1, wherein the additional pattern is a position measurement mark (IP mark).   The charged particle beam transfer mask according to claim 6, wherein the additional pattern overlaps a pattern of the pattern.   A charged particle beam transfer mask according to any one of claims 1 to 7, which is used for low-energy electron proximity projection lithography LEEPL (Low Energy Electron-Beam Proximity Projection Lithography). Transfer mask.   8. A charged particle beam transfer mask according to claim 1, wherein the transferred particle beam transfer mask is for electron projection lithography EPL (Electron-Beam Projection Lithography).   A transfer mask for a charged particle beam having a stencil mask structure in which this pattern to be transferred is formed on a membrane comprising an absorber for absorbing a charged particle beam or a scatterer for scattering a charged particle beam, and a transfer region A charged particle beam transfer mask manufacturing method for producing a charged particle beam transfer mask in which an additional pattern other than the main pattern is added to the membrane and the formation layer is added to the membrane. In order, (a) a mask layer for forming a mask that doubles as a pattern for forming the additional pattern and a mask for creating the main pattern is disposed on one surface of the membrane material for forming the main pattern. And (b) forming a first resist pattern in a predetermined shape including the additional pattern and the shape of the main pattern on the mask layer. (C) a first etching step of etching the mask layer using the first resist pattern as an anti-etching mask to form a through-hole of the first resist pattern shape; d) a first resist removing step for removing the first resist pattern; and (e) a second plate making step for forming a second resist pattern so as to cover only a predetermined region including the additional pattern region; (F) a second etching step in which the membrane material is etched using the mask layer in which the second resist pattern and the through hole are formed as an anti-etching mask to form this pattern; and (g) a second mask layer. A mask layer removing step for removing a region not covered with the resist pattern; and (h) a second resist removing step for removing the second resist pattern. The method of transferring a mask for a charged particle beam, which comprises carrying out.   11. The method for producing a transfer mask for charged particle beam according to claim 10, wherein the mask layer is a multilayer, and only the lower layer is left after the second resist removing step, and the upper layer is removed. Method for manufacturing a transfer mask for lines.   A transfer mask for a charged particle beam having a stencil mask structure in which this pattern to be transferred is formed on a membrane comprising an absorber for absorbing a charged particle beam or a scatterer for scattering a charged particle beam, and a transfer region A charged particle beam transfer mask manufacturing method for producing a charged particle beam transfer mask in which an additional pattern other than the main pattern is dug into the membrane without overlapping the main pattern. In order, (a1) a mask layer for forming a mask that also serves as a mask for forming the additional pattern and a mask for forming the main pattern is disposed on one surface of the membrane material for forming the main pattern. (B1) a first resist having a predetermined shape including an additional pattern and a shape of the main pattern on the mask layer; A first resist plate-making process for forming a pattern; and (c1) an etching process for etching the mask layer using the first resist pattern as an anti-etching mask to form a through-hole having the shape of the first resist pattern; (D1) a first resist removing step for removing the first resist pattern; and (e1) a second plate making step for forming a second resist pattern so as to cover only a predetermined region including the additional pattern region. (F1) Using the mask layer in which the through hole is formed as an anti-etching mask, the membrane material and the second resist pattern are etched to form the main pattern, and an additional pattern is formed without digging through the membrane material. Performing a second etching step to be formed, and (g1) a mask layer removing step of removing the mask layer. Method for producing a transfer mask electrostatic particle beam. The method of manufacturing a transfer mask for charged particle beam according to claim 12, wherein the thickness of the membrane made of the scattering layer material or the absorption layer material, the thickness of the second resist pattern, and the depth of the recess, When L, S, and H are set, and the etching rate of the membrane material is A and the etching rate of the second resist pattern is B, f is the overetch factor (constant) of the membrane material.
(S / B) + (H / A) = f (L / A)
Thus, S = (fL−H) / (A / B) is obtained, and the process factors f and (A / B) are determined to determine the thickness S of the second resist pattern. A method for producing a transfer mask for charged particle beams, wherein: A transfer mask for a charged particle beam having a stencil mask structure in which this pattern to be transferred is formed on a membrane comprising an absorber for absorbing a charged particle beam or a scatterer for scattering a charged particle beam, and a transfer region A charged particle beam transfer mask manufacturing method for producing a charged particle beam transfer mask in which an additional pattern other than the main pattern is superimposed on the main pattern and a concave portion is dug into the membrane. In order, (a2) a resist plate making process in which a resist pattern having an opening in the shape of the main pattern is disposed on one surface of the membrane material for forming the main pattern, with only the additional pattern forming region being thinned; and (b2 ) Etching the resist pattern and the membrane material in which the opening is formed, and the resist pattern in the additional pattern formation region And removing the resist pattern in other regions to form the main pattern and dig without penetrating the membrane material to form an additional pattern, and (c2) a resist for removing the resist pattern A method for producing a transfer mask for charged particle beams, comprising performing a layer removing step.

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