KR20050037525A - Mask substrate information producing method and mask substrate manufacturing method - Google Patents

Abstract

A process of acquiring first information indicating flatness of the main surface of the mask substrate, and simulation of when the mask substrate is set in the exposure apparatus from the first information and information on the structure of the mask chuck of the exposure apparatus; And obtaining a second information indicating the flatness, and determining whether or not the flatness of the main surface of the mask substrate obtained by the simulation meets the specification. Is provided.

Description

MASK SUBSTRATE INFORMATION PRODUCING METHOD AND MASK SUBSTRATE MANUFACTURING METHOD}

TECHNICAL FIELD The present invention relates to a method of manufacturing an exposure mask, a method of generating mask substrate information, a method of manufacturing a semiconductor device, a mask substrate, an exposure mask, and a server in the semiconductor field.

As the miniaturization of semiconductor devices proceeds, the demand for miniaturization in the photolithography process is increasing. Already, the design rules of the device have been refined to 0.13 mu m, and the dimensional precision to be controlled is required to be very strict about 10 nm. As a result, the problem in the photolithography process currently used for the semiconductor manufacturing process continues to become remarkable.

The problem is one of the factors related to the high precision of the pattern forming process, and the flatness of the mask substrate used in the lithography process. In other words, with the miniaturization, the margin of focus in the lithography process decreases, and the flatness of the mask substrate cannot be ignored.

Thus, the inventors of the present invention conducted the research on the flatness of the mask substrate.

The surface shape of a mask board | substrate differs only by various shapes, and even if it is the same flatness, it is various shapes, such as a convex shape, a concave shape, a saddle shape, and the mixed form. Therefore, even if the mask flatness is fixed (chuck) to the mask stage of the wafer exposure apparatus even with the same flatness, the mask substrate is greatly enlarged at the time of fixing due to the compatibility with the mask stage and the vacuum chuck. When deformed, hardly deformed, or conversely, flatness may be improved.

This is because the flatness of the mask substrate after fixing depends on the surface shape of the mask substrate before fixing, and the same mask substrate also changes depending on the location where the vacuum chuck is performed. However, conventionally, since only flatness is managed, depending on the surface shape of the mask substrate, the flatness of the mask substrate may be greatly deteriorated by fixing the mask substrate to the mask stage of the wafer exposure apparatus with a chuck.

And it became clear that manufacturing a semiconductor device using the exposure mask obtained by forming a pattern on the mask substrate in which such flatness was deteriorated became a big factor in the fall of product yield.

As described above, the inventors compared the flatness of the mask substrate before and after the mask substrate is fixed to the mask stage of the wafer exposure apparatus by the chuck. It was confirmed that the deterioration, and found that the deterioration of the flatness is a major factor in the product yield decline.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is effective for solving the problem of deterioration in product yield due to deterioration in flatness of the mask substrate after fixing the mask substrate to the mask stage of the wafer exposure apparatus. It is an object to provide a method of manufacturing a mask, a method of generating mask substrate information, a method of manufacturing a semiconductor device, a mask substrate, an exposure mask, and a server.

The manufacturing method of the exposure mask in the 1st viewpoint of this invention provides the 1st information which shows the surface shape of a main surface with respect to each of a plurality of mask substrates, and the flatness of the said main surface before and after fixing to the mask stage of an exposure apparatus with a chuck. The process of acquiring the 2nd information which shows a figure, the correspondence relationship of each said mask substrate, its said 1st information, and the said 2nd information is created, and the 2nd information which shows desired flatness is selected from the created correspondence relationship. A step of preparing a mask substrate having the same surface shape as the surface shape indicated by the selected second information and the first information in the corresponding relationship, and separately from the plurality of mask substrates; and on the prepared mask substrate It is characterized by including a step of forming a desired pattern.

The manufacturing method of the exposure mask in the 2nd viewpoint of this invention is the said information before and after fixing to the mask stage of the exposure apparatus of each mask substrate and each mask substrate and the 1st information which shows the surface shape of the main surface of each mask substrate. The surface shape which the 1st information which corresponds to the selected 2nd information and selects the 2nd information which shows desired flatness among the 2nd information which shows the flatness of a principal surface with respect to a some mask board | substrate is selected, And a step of separately preparing a mask substrate having the same surface shape as the plurality of mask substrates, and forming a desired pattern on the prepared mask substrate.

The manufacturing method of the exposure mask in the 3rd viewpoint of this invention creates the process of acquiring the information which shows the surface shape of a main surface, about each of a plurality of mask substrates, and the correspondence relationship of each said mask substrate and the said information. Selecting the information representing the convex surface shape among the steps to be made and the corresponding relationship created, selecting the selected information and the mask substrate in the corresponding relationship among the plurality of mask substrates, and selecting a desired pattern on the selected mask substrate. It is characterized by including the process of forming.

The manufacturing method of the exposure mask in the 4th viewpoint of this invention is the 1st information which shows the surface shape of a main surface with respect to each of a plurality of mask substrates, the flatness of the said main surface measured by the measuring apparatus, and the mask chuck of an exposure apparatus. Acquiring second information indicating flatness of the main surface by simulation when each mask substrate is set in the exposure apparatus from the structure; and between the mask substrate, the first information, and the second information. Mask which has the same surface shape as the surface shape which the said 2nd information which shows desired flatness is selected from the process of creating a correspondence relationship, and the created correspondence relationship, and this selected 2nd information and the said 1st information in the said correspondence relationship are represented. The process of preparing a board | substrate separately from the said several master board | substrate, and the space which forms a desired pattern on this prepared mask board | substrate. It characterized in that it comprises a.

The manufacturing method of the exposure mask at the 5th viewpoint of this invention is the 1st information which shows the surface shape of each mask substrate and the main surface of each mask substrate, the flatness of the said main surface measured by the measuring apparatus, and the mask chuck of an exposure apparatus. From the structure, the second information indicating the desired flatness is selected from the corresponding relations with respect to the plurality of mask substrates of the second information indicating the flatness of the main surface by simulation when the mask substrate is set in the exposure apparatus. And a step of preparing a mask substrate having the same surface shape as the surface shape indicated by the first information in correspondence with the selected second information, separately from the plurality of mask substrates, and forming a desired pattern on the prepared mask substrate. Characterized in that it comprises a step to.

The manufacturing method of the exposure mask at the 6th viewpoint of this invention is a process of acquiring the 1st information which shows the surface shape of the mask substrate and the main surface of a mask substrate, the flatness of the main surface of the said mask substrate, and the structure of the mask chuck of an exposure apparatus. Obtaining from the second information indicating the flatness of the main surface by simulation when the mask substrate is set in the exposure apparatus, and whether the flatness of the main surface of the mask substrate obtained by the simulation meets the specification. It is characterized in that it comprises a process of forming the exposure mask by determining the, and when it is determined that the specifications meet.

The mask substrate information generating method at the seventh viewpoint of the present invention includes, for each of the plurality of mask substrates, first information indicating the surface shape of the main surface and flatness of the main surface before and after the chuck is fixed to the mask stage of the exposure apparatus. And a step of acquiring the second information shown in the figure, and storing the mask substrate, the first information, and the second information in association with each other.

The mask substrate information generating method at the eighth viewpoint of the present invention includes a step of acquiring information indicating the surface shape of the main surface for each of the plurality of mask substrates, information indicating that the surface shape of the main surface is convex in the acquired information; And a step of storing a mask substrate corresponding thereto.

The mask substrate information generating method at the ninth time point of the present invention includes, for each of the plurality of mask substrates, first information indicating the surface shape of the main surface, flatness of the main surface measured by the measuring device, and mask chuck of the exposure apparatus. Acquiring second information indicating flatness of the main surface by simulation when each mask substrate is set in the exposure apparatus from the structure; and causing the respective mask substrates to correspond to the first information and the second information. It is characterized by including the process of storing.

The manufacturing method of the semiconductor device at the 10th viewpoint of this invention is a process of fixing the exposure mask manufactured by the manufacturing method of the exposure mask in any one of said 1st-3rd viewpoint with the chuck on the mask stage of an exposure apparatus, Illuminating the pattern formed on the exposure mask by an illumination optical system, and forming an image on the desired substrate using the image of the pattern; and patterning the layer on which the image on the desired substrate is formed based on the image forming. It is characterized by including the process used for formation.

A semiconductor device manufacturing method according to an eleventh aspect of the present invention includes a substrate having a main surface and a pattern including a light shielding body formed on the main surface, wherein the surface shape of the peripheral region of the main surface is the peripheral side of the substrate. And a step of fixing the exposure mask having a shape lower than the surface of the central region of the main surface with a chuck on the mask stage of the exposure apparatus, and illuminating a pattern formed on the exposure mask with an illumination optical system to produce an image of the pattern. And forming an image on a desired substrate by a projection optical system, and patterning the layer on which the image formation on the desired substrate is formed on the basis of the image formation to form a semiconductor element.

The mask substrate at the 12th viewpoint of this invention is equipped with the board | substrate which has a main surface, and the light shielding body which coat | covers the said main surface, The surface shape of the periphery area | region of the said main surface is centered on the said main surface toward the peripheral side of the said board | substrate. It is characterized by the fact that the shape is lower than the surface of the region.

An exposure mask at a thirteenth viewpoint of the present invention includes a substrate having a main surface and a pattern including a light shielding body formed on the main surface, wherein the surface shape of the peripheral region of the main surface is toward the peripheral side of the substrate. The height is lower than the surface of the center area of the said main surface, It is characterized by the above-mentioned.

The server at the 14th viewpoint of this invention is the flatness of the said main surface before and after fixing to the mask stage of the exposure apparatus of each mask substrate and each mask substrate and the surface shape of the main surface of each mask substrate by the chuck | zipper. Means for performing a process for storing a page including information indicating a correspondence relation to a plurality of mask substrates of the second information shown in the drawing; and processing for receiving a request message for the page from a client. Means for performing, processing for transmitting the page in a form that can be displayed on the client side, and means for performing processing for receiving an application message of the substrate mask from the client that transmitted the page. Characterized in that comprises a.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

Embodiment of the Invention

EMBODIMENT OF THE INVENTION Hereinafter, the Example of this invention is described, referring drawings.

(First embodiment)

1 is a flowchart showing the flow of a method of manufacturing an exposure mask according to a first embodiment of the present invention.

First, the size of 152 mm 2 and 11 mask substrates A to K formed by forming a light shielding body covering the film on a quartz substrate having a thickness of about 6 mm is prepared. For each of these mask substrates A to K, the main surface is prepared. Is measured by a substrate flatness measuring device (manufactured by Nidex), and the surface shape and flatness of the main surfaces of the 11 mask substrates A to K before fixing to the mask stage of the exposure apparatus with a vacuum chuck are obtained (step S1). ).

Here, in FIG. 2A, the flatness of the 142 mm 2 area (first area: 1) except the peripheral area of the mask substrate is measured. The first region 1 is a pattern formation region that actually forms a pattern.

In addition, in this embodiment, the surface shape of the 1st area | region 1 is convex, and concave connects both ends of the 1st area | region 1 as shown to FIG.2 (b) and FIG.2 (c), respectively. It means a shape which is convex upward or concave downward with respect to the line L1. Fig. 3 (a) and Fig. 3 (b) show an overview of the convex and concave downwards of the surface shape, respectively.

On the other hand, the surface shape of the second region 2 is convex or concave, as shown in Fig. 2D, toward the periphery of the mask substrate, the height of which is lower than the surface of the first region 1. It means a thing (convex) or a rising shape (concave). The second region 2 will be described in detail in the second embodiment.

Subsequently, based on the acquisition result, each of the 11 mask substrates A to K is classified for each kind of surface shape of the main surface (step S2). The results are shown in Table 1. The kind (first information) of the surface shape was classified into four types of convex shape, concave shape, saddle shape and center convex shape from the said measurement result. In addition, the flatness measurement value (second information) of the 1st area | region 1 before fixing to the mask stage was in the range of 0.4 micrometer-0.5 micrometer. Fig. 3 (c) and Fig. 3 (d) show the saddle shape and the center convex overview of the surface shape, respectively.

Mask substrate Flatness before fixing the chuck (㎛) Surface shape before chuck fixation Flatness after fixing the chuck (㎛) A 0.5 Convex shape 0.4 B 0.4 Convex shape 0.4 C 0.45 Convex shape 0.4 D 0.5 Concave shape 0.8 E 0.5 Concave shape 1.0 F 0.4 Saddle shape 0.9 G 0.5 Saddle shape 0.9 H 0.4 Center convex shape 0.4 I 0.5 Center convex shape 0.4 J 0.5 Center convex shape (90 degrees rotation) 0.2 K 0.5 Center convex shape (90 degrees rotation) 0.3

Subsequently, the 11 mask substrates A to K are sequentially fixed to a mask stage of an ArF wafer exposure apparatus (manufactured by Nikon Corporation) with a vacuum chuck, and the flatness of the main surface of each mask substrate after fixing with the vacuum chuck is measured (step S3). Here, the flatness of the 1st area | region 1 (FIG. 2 (a)) of 142 mm <2> except the peripheral region of the mask substrate was measured. Then, as shown in Table 1, about 11 mask substrates A-K, the correspondence relationship between the kind of surface shape and the value of the flatness before and behind fixing by a vacuum chuck is created (step S4).

As can be seen from Table 1, the flatness after fixing the convex mask substrates A to C with the chuck is the same or slightly better than before the fixing with the chuck, but the surface of the concave and saddle mask substrates D to G The flatness is greatly deteriorated after fixing with the chuck.

In addition, about the mask substrate whose surface shape is a convex center, what arrange | positioned the arrangement direction of the mask substrate on the mask stage in a predetermined direction with respect to the chuck (mask substrates H and I), the direction orthogonal to this predetermined direction, That is, the flatness measurement was performed about what replaced the mask substrate location (mask substrate J, K) arrange | positioned in the direction rotated 90 degree | times, and is fixed by the chuck.

As a result, as shown in Table 1, it became clear that the flatness after fixing the center convex mask substrates H-K with a vacuum chuck changes with the arrangement direction of the mask substrate with respect to a chuck.

That is, it became clear that the flatness after fixing the convex mask substrates H-K with a vacuum chuck also changes with the location of the mask substrate fixed with a vacuum chuck.

Specifically, when the arrangement direction of the mask substrate on the mask stage, such as the mask substrates H and I, is arranged in a predetermined direction with respect to the chuck, the edge of the convex bow is in contact with the chuck of the mask stage of the exposure apparatus. Although the flatness is hardly improved, on the other hand, when disposed in the direction rotated 90 degrees like the mask substrates J and K, the flat convex bow does not touch the chuck of the mask stage of the exposure apparatus, and thus the flatness is 0.3 μm or less. It was confirmed that the flatness was improved (Table 1). In addition, the reason why the rotation on the other surface-shaped mask substrates A to G is not shown in Table 1 is that the flatness was not improved even when the surface was rotated.

Subsequently, the flatness which meets a specification is made out of the mask substrate group which consists of 11 mask substrates A-K which knows the kind of surface shape before and after fixing by a vacuum chuck, and the value of flatness in advance as mentioned above. The mask substrate which has the same kind of surface shape as the mask substrate to have is prepared separately from 11 mask substrates A-K (step S5). Here, the case where the thing of the same shape as the mask substrate J is selected as this mask substrate prepared separately is demonstrated.

The mask substrates A to K and the mask substrate prepared separately are formed so that the flatness of the pattern formation region falls within a predetermined specification, and the difference in the surface shape is caused by variation.

Subsequently, a resist is applied onto the separately prepared master substrate.

Then, the manufacturing process of the exposure mask which is a well-known manufacturing method is performed. That is, a desired pattern is drawn in the resist on the mask substrate by the electron beam drawing apparatus. Subsequently, the resist is developed to form a resist pattern. Subsequently, the light shield of the mask substrate is etched by a reactive ion etching apparatus to form the light shield by using the resist pattern as a mask. Thereafter, the resist pattern is peeled off, and the surface of the mask substrate is subsequently washed to complete the exposure mask on which the desired mask pattern is formed (step S6). The desired pattern includes, for example, a circuit pattern, or includes a circuit pattern and a position alignment pattern.

The exposure mask thus obtained was set in the ArF wafer exposure apparatus, and the principal surface flatness was measured. As a result, it was confirmed that a good value was obtained at 0.2 µm. The exposure mask having a high flatness is fixed on the mask stage of the exposure apparatus by a chuck, the pattern formed on the exposure mask is illuminated by an illumination optical system, and the image of the pattern is projected by a projection optical system (for example, By adopting an exposure method for forming an image on a resist-coated substrate), the margin of focus during wafer exposure is greatly increased, and the yield of semiconductor products such as DRAM is greatly improved.

In this way, according to this embodiment, the manufacture of an exposure mask effective for solving the problem of a drop in product yield caused by deterioration in the flatness of the main surface of the mask substrate by fixing the mask substrate to the mask stage of the wafer exposure apparatus with a chuck. The method can be realized.

The mask substrates A to K and the mask substrate to be prepared separately may be previously formed with a mark for alignment. The means for fixing the mask substrate to the mask stage with the chuck is not limited to the vacuum chuck.

(2nd Example)

In the first embodiment, the surface shape and flatness were acquired only for the first region 1 of the main surface of the mask substrate 1 shown in Fig. 2A (step S1), but in the present embodiment, the first region was obtained. The surface shape and the flatness of each of the two regions of (1) and the second region 2 surrounding the first region 1 are obtained.

Here, the 1st area | region 1 is a rectangular area | region whose length of one side is 142 mm which made the mask substrate center the center of the area | region, and the 2nd area | region 2 has the 1 area | region which surrounds the 1st area | region 1 here. It is a 150 mm long frame-shaped area (the area excluding the rectangular area smaller than that with the center of the rectangular area as the center of the area from the rectangular area). The area | region (mask chuck area | region) fixed by the vacuum chuck at the time of setting the mask substrate 1 to the mask stage of an exposure apparatus is contained in the 2nd area | region 2 substantially. In other words, most of the force for the chucking of the mask substrate to the mask stage acts on the second region 2.

In consideration of managing the flatness of not only the pattern formation region but also the mask chuck region on the extension lines of the prior art, the first region 1 is expanded, thereby managing the flatness of the region including the mask chuck region. .

However, in the present mask fabrication technology, it is very difficult to flatten the entire main surface of the mask substrate 1, and the phenomenon that the flatness of the main surface of the mask substrate 1 is rapidly deteriorated at the end is a phenomenon, thereby causing the first region. When (1) is widened, the flatness of the center part of the mask substrate 1 is good, but since the flatness of the edge part of the mask substrate 1 is bad, the flatness measurement result with respect to the whole main surface of the mask substrate 1 will fall. do. Thus, in the present embodiment, as described above, the flatness and the surface shape are acquired for each of the first region 1 including the mask center and the second regions 2 surrounding the mask region.

The flatness and the surface shape of the main surface of the mask substrate formed by forming a light shielding body on a quartz substrate having a size of 152 mm2 and a thickness of about 6 mm were measured with a substrate flatness measuring device (manufactured by Nidex), and the first region ( 13 mask substrates A to M having the flatness and surface shape of 1) and the flatness and surface shape of the second region 2 were prepared.

Subsequently, these 13 mask substrates A-M were set in order in ArF wafer exposure apparatus (made by Nikon Corporation), and the flatness measurement of each mask substrate main surface after fixing with a vacuum chuck was performed.

Next, about 13 mask substrates A-M, the correspondence relationship between the kind of surface shape and the value of the flatness of the 1st and 2nd area | region before and after fixing with a vacuum chuck was created. The results are shown in Table 2.

First zone (before chuck fixed) Second area (before chuck fixed) First zone (after anchoring chuck) Mask substrate Flatness (㎛) Surface shape Flatness (㎛) Surface shape Flatness (㎛) A 0.3 Convex shape 4 Convex shape 0.3 B 0.3 Convex shape 3 Concave shape 1.5 C 0.35 Convex shape 4 Center convex shape 0.6 D 0.35 Convex shape 4 Center convex shape (rotated 90 degrees) 0.3 E 0.35 Convex shape 4 Saddle shape 1.0 F 0.35 Concave shape 4 Convex shape 0.3 G 0.35 Concave shape 4 Concave shape 0.8 H 0.35 Concave shape 4 Center convex shape 0.8 I 0.35 Concave shape 4 Center convex shape (rotated 90 degrees) 0.4 J 0.35 Concave shape 4 Saddle shape 0.9 K 0.5 Saddle shape 3 Saddle shape 1.0 L 0.5 Center convex shape 3 Center convex shape 0.9 M 0.4 Center convex shape 3 Center convex shape (rotated 90 degrees) 0.4

The surface shapes of the first and second regions of the thirteen mask substrates A to M were classified into four types: convex, concave, saddle and middle convex. The surface shape of the 1st and 2nd area | region of the mask substrate A which is a convex shape with a simple surface shape was both convex. On the other hand, the surface shape of the mask board | substrate B of the shape like a hat with a shade was convex in a 1st area | region, and was concave in a 2nd area | region.

Table 2 shows that the mask substrate which deteriorates the planar shape of a 1st area | region by fixing with a vacuum chuck is concave and saddle-shaped. In addition, the mask substrates C, D, H, I, L, and M whose surface shape is convex in the center showed different results depending on the arrangement direction of the mask substrate on the mask stage.

In detail, when the arrangement direction of the mask substrate on the mask stage is arranged in a predetermined direction with respect to the chuck, the flat convex bow shape touches the chuck of the mask stage of the exposure apparatus, but the flatness decreases. When placed in a direction rotated by 90 degrees, the flat convex bow does not touch the chuck of the mask stage of the exposure apparatus, and the flatness is 0.4 µm or less, and most masks arranged in this direction (direction rotated by 90 degrees) It was confirmed that the flatness of the substrate was improved.

Moreover, the flatness of the 1st area | region after fixation by a vacuum chuck also confirmed that it was almost independent of the surface shape of the 1st area | region before fixing. That is, the shape change of the main surface of the mask substrate before and after fixing by the vacuum chuck is almost determined from the surface shape of the second region.

Further, although the flatness of the second region is a very bad value compared to the flatness of the first region, when the surface shape of the second region is convex, the surface shape of the first region of the mask substrate after fixing by the vacuum chuck Was almost unchanged.

In view of the above, the correspondence relation between the types of the surface shapes of the first region 1 and the second region 2 and the flatness of the main surface of the mask substrate before and after fixing by the vacuum chuck with respect to the plurality of mask substrates is shown. By making it necessary, it is unnecessary to make the first region 1 of the mask substrate wider than necessary in order to manage the flatness of the mask chuck region, thereby making the flatness of the first region 1 more than necessary and realistic. By taking the value into consideration and considering the surface shape of the second region 2, it is possible to more reliably select a mask substrate with less variation in the flatness of the main surface of the mask substrate before and after the fixing by the vacuum chuck.

Subsequently, the kind of surface shape of the 1st area | region 1 and the 2nd area | region 2 before fixing by a vacuum chuck and the value of the flatness after fixing with the chuck | zipper of the mask substrate main surface in advance as mentioned above are known, From the mask substrate group which consists of 13 mask substrates A-M, the mask substrate which has the same kind of surface shape as the mask substrate which has the flatness according to specification is prepared separately from 13 mask substrates A-M.

Here, as the mask substrate to be prepared separately, one having the same surface shape as the mask substrate F (the first region was concave and the second region was convex) was prepared. When the mask substrate was measured, the flatness of the first region was 0.3 µm or less, and the flatness of the second region was 4 µm or less.

Subsequently, a resist was applied onto the mask substrate.

Then, the manufacturing process of the exposure mask which is a well-known manufacturing method is performed. That is, a desired pattern is drawn in the resist on the mask substrate by the electron beam drawing apparatus. Subsequently, the resist is developed to form a resist pattern. Subsequently, the light shield of the mask substrate is etched by a reactive ion etching apparatus to form the light shield by using the resist pattern as a mask. Thereafter, the resist pattern is peeled off, and the surface of the mask substrate is subsequently washed to complete an exposure mask having a desired mask pattern formed thereon. The desired pattern includes, for example, a circuit pattern, or includes a circuit pattern and a position alignment pattern.

The exposure mask obtained by doing in this way was set in the ArF wafer exposure apparatus, and when the flatness of the 1st area was measured, it was confirmed that favorable flatness was obtained by 0.2 micrometer. The exposure mask having a high flatness is fixed on the mask stage of the exposure apparatus by a chuck, the pattern formed on the exposure mask is illuminated by an illumination optical system, and the image of the pattern is projected by a projection optical system (for example, By adopting an exposure method for forming an image on a resist-coated substrate), the margin of focus during wafer exposure is greatly increased, and the yield of semiconductor products such as DRAM is greatly improved.

In this way, the present embodiment is also effective in solving the problem of lowering the product yield due to the deterioration of the flatness of the main surface of the mask substrate after the mask substrate is fixed to the mask stage of the wafer exposure apparatus in the same manner as in the first embodiment. The manufacturing method of an exposure mask can be implement | achieved.

The mask board | substrates A-M and the mask board | substrate prepared separately may be previously formed with the mark for position alignment. The means for fixing the mask substrate to the mask stage with the chuck is not limited to the vacuum chuck.

Moreover, since the flatness of the 1st area | region after fixing by a vacuum chuck is good that the surface shape of a 2nd area | region is convex from Table 2, the mask substrate or exposure mask whose surface shape of the 2nd area | region is convex form is created, You can use it.

In the second region, the mask substrate or the exposure mask having the above-described surface shape, that is, the convex shape, uses a faster polishing rate in the center region in the peripheral region and the inner region (center region) of the quartz substrate, for example. It can be obtained by. If it demonstrates concretely, it can obtain by grind | polishing the main surface of a quartz substrate longer than before using a grinding | polishing apparatus. Thereafter, a light shielding body is formed by a well-known method to obtain a mask substrate. An exposure mask can be obtained by patterning the light shielding body again.

And the exposure mask which formed the 2nd area | region which has such a predetermined surface shape (here, convex) is fixed to the chuck | zipper stage on the mask stage of an exposure apparatus, illuminating the pattern formed on the said exposure mask with an illumination optical system, and By adopting an exposure method in which an image of the pattern is formed on a desired substrate (for example, a substrate coated with a resist), the focus margin at the time of exposure to a wafer is greatly increased as in the first embodiment, and semiconductor products such as DRAMs are used. The yield is greatly improved.

Moreover, conventionally, the quartz substrate was polished so that the entire main surface could be as flat as possible. Therefore, the control to lengthen the polishing time is not intentionally performed so that the difference in polishing rate is not remarkable. Therefore, even if the surface shape of a 2nd area | region becomes convex or concave by the fluctuation | variation of grinding | polishing, the grade becomes a thing smaller clearly than that of the mask substrate and exposure mask of a present Example.

(Third Embodiment)

In this embodiment, the surface shape of the main surface of the mask substrate corresponding to the surface shape of the main surface of the mask substrate after being fixed by the vacuum chuck is obtained by simulation.

First, the surface shape and flatness of the main surface of the mask substrate formed by forming a light shielding body on a quartz substrate having a size of 152 mm2 and a thickness of about 6 mm are defined as the pattern forming region (the first region ((a) of FIG. The flatness of 1)) was calculated | required by measuring with the board | substrate flatness measuring apparatus (made by Nidex company), and 13 mask substrates A-M which differ in surface shape and flatness were prepared, respectively.

Subsequently, the mask chuck structure of the ArF wafer exposure apparatus (manufactured by Nikon Corporation) and the measured flatness of the main surfaces of the 13 mask substrates A to M are applied to the mask stage of the ArF wafer exposure apparatus using the finite element method. The flatness of the main surface of the mask substrates A-M when 13 mask substrates A-M were fixed in order by the vacuum chuck was acquired by simulation. Instead of the finite element method, analytical methods may be used. Subsequently, in order to confirm whether or not the simulation is correct, the 13 mask substrates A to M are actually fixed to the ArF wafer exposure apparatus in order with a vacuum chuck, and the flatness of the main surface of each mask substrate after the fixing by the vacuum chuck is performed. The measurement was carried out. As a result, the flatness of the main surfaces of the mask substrates A to M obtained by the simulation and the flatness of the main surfaces of the mask substrates A to M obtained by the measurement using the substrate flatness measuring device actually set in the ArF wafer exposure apparatus are shown in Table 3 below. As shown in FIG. 1, it was confirmed that there was only a difference of 0.1 μm or less in most mask substrates of the mask substrates A to M. FIG.

Mask substrate Measurement data of the main surface of the mask substrate Flatness by simulation Flatness after chucking Flatness (㎛) Surface shape Flatness (㎛) Flatness (㎛) A 0.3 Convex shape 0.3 0.3 B 0.3 Convex shape 1.5 1.5 C 0.35 Convex shape 0.6 0.6 D 0.35 Convex shape 0.3 0.3 E 0.35 Convex shape 1.0 1.0 F 0.35 Concave shape 0.5 0.3 G 0.35 Concave shape 0.7 0.8 H 0.35 Concave shape 0.8 0.8 I 0.35 Concave shape 0.5 0.4 J 0.35 Concave shape 0.9 0.9 K 0.5 Saddle shape 1.3 1.0 L 0.5 Center convex shape 0.9 0.9 M 0.4 Center convex shape 0.4 0.4

That is, with respect to the mask substrate, in the preparation of the correspondence relationship between the type of surface shape in the above embodiment and the value of the flatness before and after the fixing by the vacuum chuck, the value of the flatness before and after the fixing by the vacuum chuck is simulated. It can substitute by the value acquired by.

From these results, the surface shape of the main surface of the mask substrate is determined by measuring the flatness of the pattern formation region (first region 1 in FIG. 2A) by a substrate flatness measuring device (manufactured by Nidex). Subsequently, from the mask chuck structure of the exposure apparatus and the above-described flatness of the main surface of the master substrate already obtained, the surface shape of the main surface of the mask substrate when the mask substrate is fixed to the mask stage of the exposure apparatus in turn by a vacuum chuck is simulated. It was found that the surface shape of the main surface of the mask substrate when the mask substrate was set in the wafer exposure apparatus can be predicted. Therefore, it is possible to manage the surface shape and flatness of the main surface of the mask substrate with higher accuracy than before.

4 is a flowchart showing a flow of a method of manufacturing an exposure mask according to a third embodiment of the present invention. In the flowchart of FIG. 4, the surface shape of the main surface of the mask substrate when the mask substrate is fixed by the vacuum chuck in step S3 is obtained by simulation. And the correspondence relationship between the flatness acquired using the surface shape and the board | substrate flatness measuring apparatus in step S4, and the flatness acquired by simulation is created. Steps S1, S2, S5, and S6 are the same as in the flowchart of FIG.

Subsequently, the surface shape of the main surface of the mask substrate is measured by the substrate flatness measuring device, and the surface shape of the main surface of the mask substrate when the mask substrate is fixed to the mask stage of the exposure apparatus in turn by a vacuum chuck is simulated. A mask substrate proved to have a flatness of 0.2 µm was prepared separately from the 13 mask substrates A to M in step S5.

Then, the manufacturing process of the exposure mask which is a manufacturing method well-known in step S6 is performed. That is, a desired pattern is drawn in the resist on the mask substrate by the electron beam drawing apparatus. Subsequently, the resist is developed to form a resist pattern. Subsequently, the light shielding body of the mask substrate is etched by a reactive ion etching apparatus to form a light shielding body pattern (mask pattern) using the resist pattern as a mask. Thereafter, the resist pattern is peeled off, and the surface of the mask substrate is subsequently washed to complete an exposure mask having a desired mask pattern formed thereon. The exposure mask was actually set in an ArF wafer exposure apparatus, and the surface shape and flatness of the main surface thereof were measured using a substrate flatness measuring device. As a result of simulation, it was confirmed that the flatness of 0.2 μm was good. there was. The exposure mask having a high flatness is fixed on the mask stage of the exposure apparatus by a chuck, and the pattern formed on the exposure mask is illuminated by an illumination optical system, so that the image of the pattern is projected by a projection optical system (for example, By adopting an exposure method for forming an image on a resist-coated substrate), the margin of focus during wafer exposure is greatly increased, and the yield of semiconductor products such as DRAM is greatly improved.

By doing so, also in the present embodiment, as in the first and second embodiments, the flatness of the main surface of the mask substrate is deteriorated after the mask substrate is fixed to the mask stage of the wafer exposure apparatus by the chuck. It is possible to realize a method of manufacturing an exposure mask effective for solving the problem of.

The mask board | substrates A-M and the mask board | substrate prepared separately may be previously formed with the mark for position alignment. In addition, the means for fixing the mask substrate to the mask stage by the chuck is not limited to the vacuum chuck.

In each of the above-described embodiments, for example, the wafer exposure apparatus may not be an ArF wafer exposure apparatus. In addition, after mask pattern formation, the flatness of the principal surface of a mask substrate is measured again, and the surface shape of the principal surface of the mask substrate at the time of setting a mask substrate in the exposure apparatus from the measurement data may be acquired by simulation. As a result, the deformation of the main surface of the mask substrate generated at the time of forming the mask pattern is also obtained as a result of acquisition by simulation, so that the surface shape and flatness of the main surface of the mask substrate with higher precision can be managed. The mask is also not limited to ArF and KRF, but can also be applied to, for example, a reflective mask for vacuum ultraviolet exposure, a mask for X-ray exposure, a mask for electron beam exposure, and the like.

(Example 4)

In this embodiment, the surface shape of the main surface of the mask substrate which corresponds to the surface shape of the main surface of the mask substrate after fixing by the vacuum chuck is acquired by simulation.

5 is a flowchart showing the flow of the manufacturing method of the exposure mask according to the present embodiment.

In step S1, the surface shape and flatness of the main surface of one mask substrate formed by forming a light shielding body on a quartz substrate having a size of 152 mm2 and a thickness of about 6 mm are shown in the pattern formation region (Fig. 2 (a)). The flatness of the 1st area | region 1 of this was calculated | required by measuring with the board | substrate flatness measuring apparatus (made by Nidex Corporation).

Subsequently, from the mask chuck structure of the ArF wafer exposure apparatus (manufactured by Nikon Corporation) and the measured flatness of the main surface of the mask substrate in step S2, the 1st mask is applied to the mask stage of the ArF wafer exposure apparatus using a finite element method. The flatness of the main surface of the mask substrate when the mask mask substrate was fixed in turn by a vacuum chuck was obtained by simulation. Alternatively, an analytical method may be used instead of the finite element method.

Subsequently, it is determined whether the flatness of the main surface of the mask substrate obtained by the simulation in step S3 satisfies the specification, and when it is determined that the specification satisfies the specification, the process proceeds to the manufacturing process of the exposure mask in step S4.

On the other hand, when it is determined in step S3 that the flatness of the mask substrate does not meet specifications, the light shielding film on the quartz substrate of the mask substrate is peeled off in step S5. Next, the surface of the quartz substrate is polished in step S6. Next, a light shielding body film is newly formed on the polished surface of the quartz substrate in step S7, and the process returns to the flatness measurement of step S1.

Also in this embodiment, as in the first, second, and third embodiments, the flatness of the main surface of the mask substrate is deteriorated after the mask substrate is fixed to the mask stage of the wafer exposure apparatus by the chuck. It is possible to realize a method of manufacturing an exposure mask that is effective for solving the problem of lowering of yield.

In addition, the said mask substrate may be previously formed with the mark for position alignment. The means for fixing the mask substrate to the mask stage by the chuck is not limited to the vacuum chuck.

For example, the wafer exposure apparatus may not be an ArF wafer exposure apparatus. In addition, after mask pattern formation, the flatness of the principal surface of a mask substrate is measured again, and the surface shape of the principal surface of the mask substrate at the time of setting a mask substrate in the exposure apparatus from the measurement data may be acquired by simulation. As a result, the deformation of the main surface of the mask substrate generated at the time of forming the mask pattern is also obtained as a result of acquisition by simulation, so that the surface shape and flatness of the main surface of the mask substrate with higher precision can be managed. The mask is also not limited to ArF or KRF, and can be applied to, for example, a reflective mask for vacuum ultraviolet exposure, a mask for X-ray exposure, a mask for electron beam exposure, and the like.

(Example 5)

Next, a description will be given of a mask substrate information generating method according to a fifth embodiment of the present invention.

In the mask substrate information generating method of this embodiment, before and after each of the 11 mask substrates A to K in Table 1 is fixed with the surface shape and the chuck of the main surface according to, for example, steps S1 to S3 in the flowchart of FIG. The process of acquiring the flatness of the main surface of the film, the process of matching the mask substrate and the type of the surface shape and the value of the flatness with respect to the 11 mask substrates A to K, and the correspondence The process of storing in a personal computer (PC) etc. is included.

In addition, the correspondence stored in a personal computer (PC) or the like may be presented. When it demonstrates concretely, you may make it stick the seal which printed the presentation content to the container which accommodated 11 mask substrates A-K, for example.

By adopting the method of this presentation with respect to the above correspondence, the problem of a decrease in product yield due to the deterioration of flatness of the main surface of the mask substrate after fixing the mask substrate to the mask stage of the wafer exposure apparatus is solved. Effective mask substrate management can be performed easily.

In addition, after step S2 of the flowchart of FIG. 1, among the information acquired by step S2 of the flowchart of FIG. 1, the information whose surface shape of a main surface shows convex form and the mask substrate corresponding to it correspond, and correspond the correspondence with a personal computer (PC). ), The mask substrate information generation method different from the mask substrate information generation method of this embodiment can be implemented. Also in this case, similarly to the mask substrate information generation method of the present embodiment, the mask substrate can be easily managed by presenting the correspondence with the seal or the like.

Here, although the mask substrate information generation method was demonstrated using the 11 mask substrates A-K of Table 1 as an example, mask substrate information generation can be similarly performed also about 13 mask substrates A-M of Table 2 here. .

(Example 6)

6 is a diagram schematically showing a server system according to a sixth embodiment of the present invention. In the fifth embodiment, although the thread is taken as an example of the presentation, in the present embodiment, the present embodiment is presented on a server (server apparatus), and thus the mask substrate information generation method of this embodiment can be used for e-business (e-mail business). Will be.

First, for example, in the FAB 11, a table such as Table 1, Table 2, or Table 3 showing correspondence is created, and a page including this as information is uploaded to the server 12. FIG. The server 12 stores the page in a storage means such as a hard disk.

The server 12 is connected to a plurality of clients (client devices) 13 via the Internet. You can also use a leased line instead of the Internet. Alternatively, the Internet may be a combination of a dedicated line.

The server 12 includes well-known means for performing processing for receiving a request message for the page from the client 13, and well-known for performing processing for transmitting the page in a form that can be displayed on the client side. And a well-known means for performing a process for receiving a request message of a substrate mask from the client 13 which has transmitted the page. These well-known means comprise a LAN card, a memory | storage device, server software, a CPU, etc., for example, and they cooperate and a desired process is performed.

When the server 12 receives the request message for the page from the client 13, the server 13 sends information required to display the screen 14 as shown in FIG. 3 on the display of the client 13 to the client 13. Send. The screen 14 includes a table 15 having the contents shown in Table 1, a check box 16 for selecting and checking a desired mask substrate, and a decision to purchase a mask substrate checked in the check box. The decision icon 17 for passing to the server 12 is displayed. In FIG. 6, although the table 15 which has the content shown in Table 1 was shown for simplicity, the table of the content shown in Table 2 or the content shown in Table 3 may be used.

According to this embodiment, since the mask substrate having high flatness can be purchased after the mask substrate is fixed to the mask stage of the wafer exposure apparatus, the flatness of the main surface of the mask substrate after the mask substrate is fixed to the mask stage with the chuck is fixed. It is possible to realize an effective server for solving the problem of a drop in product yield due to deterioration.

As mentioned above, although the Example of this invention was described, this invention is not limited to these Examples. For example, in the said Example, although the convex mask board | substrate had a favorable result, the exposure apparatus which sets a mask board | substrate may obtain a better result with a concave mask board | substrate. That is, since the flatness of the mask substrate after the vacuum chuck is greatly influenced by the shape of the mask chuck stage and the shape of the mask chuck surface, the shape of the mask main surface to be selected is changed by the mask chuck stage to be used.

In the above embodiments, the case of a mask substrate for an ArF wafer exposure apparatus has been described. As another mask substrate, for example, a mask substrate for KrF wafer exposure apparatus, a reflective mask substrate for vacuum ultraviolet exposure, or an X-ray exposure It can also be used for a mask substrate, a mask substrate for electron beam exposure, and the like.

In addition, each of the above embodiments includes several steps of invention, and various inventions can be extracted by appropriate combinations of the plurality of configuration requirements disclosed. For example, even if some of the configuration requirements are deleted from all the configuration requirements presented in the embodiments, when the problem described in the column of the problem to be solved by the invention can be solved, the configuration from which the configuration requirement has been removed is extracted as the invention. Can be. Other modifications can be made without departing from the spirit of the invention.

As described above, according to the present invention, the manufacture of an exposure mask effective for solving the problem of product yield reduction caused by the deterioration of the flatness of the main surface of the mask substrate after the mask substrate is fixed to the mask stage of the wafer exposure apparatus. The method, the mask substrate information generation method, the manufacturing method of the semiconductor device, the mask substrate, the exposure mask, and the server can be realized.

1 is a flow chart showing the flow of a method of manufacturing an exposure mask according to a first embodiment of the present invention.

FIG. 2A is a plan view of the main surface of the mask substrate 1 for explaining the first and second regions, and FIG. 2B is a view for explaining the first region 1 of the mask substrate. As a cross-sectional view of the first region 1, FIG. 2C is a diagram for explaining the first region 1 of the mask substrate, and another cross-sectional view of the first region 1, FIG. Is a figure for demonstrating the 2nd area | region 2 of a mask substrate, Comprising: It is sectional drawing of the 2nd area | region.

FIG. 3A is a view for explaining the first region 1 of the mask substrate. An overview perspective view of the first region 1 is shown. FIG. 3B shows the first region 1 of the mask substrate. As an explanatory drawing, another overview perspective view of the first area 1, FIG. 3C is a view for explaining the first area 1 of the mask substrate, and another overview of the first area 1. 3: (d) is a figure for demonstrating the 1st area | region 1 of a mask substrate, and another overview perspective view of the 1st area | region 1. FIG.

4 is a flowchart showing a flow of a method of manufacturing an exposure mask according to a third embodiment of the present invention.

5 is a flowchart showing a flow of a method of manufacturing an exposure mask according to a fourth embodiment of the present invention.

6 is a diagram schematically showing a server according to a sixth embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

1: first area

2: second region (pattern forming region)

11: FAB

12: server

13: client

14: Screen

15: table

16: check box

17: decision icon

Claims (19)

Acquiring first information indicating flatness of the main surface of the mask substrate; Obtaining second information indicating flatness of the main surface by simulation when the mask substrate is set in the exposure apparatus from the first information and information on the structure of the mask chuck of the exposure apparatus; A step of determining whether the flatness of the main surface of the mask substrate obtained by the simulation is within specification Mask substrate information generation method comprising a. Each main surface of the plurality of mask substrates has a first region in which a main pattern is formed, and a second region in which the chuck is fixed to the mask stage of the exposure apparatus. Acquiring first information indicating flatness of the first region of the main surface of these mask substrates; Acquiring second information indicating flatness of the second region of the main surface of these mask substrates; Storing the first information and the second information in association with each other; Mask substrate information generation method comprising a. 3. The mask substrate information generating method according to claim 2, comprising the step of selecting a mask substrate whose surface shape of the second information is convex. Acquiring first information indicating the surface shape of the main surface of the mask substrate and second information indicating the flatness of the main surface before being fixed to the mask stage of the exposure apparatus by the chuck; Obtaining third information indicating the flatness of the main surface when the mask substrate on the mask stage of the exposure apparatus is disposed in a direction rotated by 0 degrees and 90 degrees with respect to the chuck and fixed by the chuck; A process of acquiring information on whether or not the third information acquired by the above process satisfies the specification; Mask substrate information generation method comprising a. The main surface of the mask substrate mainly includes a first region in which a pattern is formed, and a second region in which a chuck is fixed to the mask stage of the exposure apparatus. Acquiring first information indicating flatness of the first region of the main surface of the mask substrate; Acquiring second information indicating flatness of the second region of the main surface of the mask substrate; Acquiring third information representing the flatness of the first region when the chuck is fixed to the mask stage of the exposure apparatus; Storing the mask substrate in association with the first, second, and third information Mask substrate information generation method comprising a. Acquiring first information indicating the surface shape of the main surface of the mask substrate and second information indicating the flatness of the main surface before being fixed to the mask stage of the exposure apparatus by the chuck; Obtaining third information indicating the flatness of the main surface when the mask substrate on the mask stage of the exposure apparatus is disposed in a direction rotated by 0 degrees and 90 degrees with respect to the chuck and fixed by the chuck; Storing the first, second and third information of the mask substrates in correspondence Mask substrate information generation method comprising a. Acquiring first information indicating the surface shape of the main surface of the mask substrate and second information indicating the flatness of the main surface before being fixed to the mask stage of the exposure apparatus by the chuck; Obtaining third information indicating the flatness of the main surface when the mask substrate on the mask stage of the exposure apparatus is disposed in a direction rotated by 0 degrees and 90 degrees with respect to the chuck and fixed by the chuck; Storing the first, second, and third information of the mask substrates in correspondence with each other; Obtaining information about whether the third information satisfies the specification; Mask substrate information generation method comprising a. The mask substrate information according to any one of claims 5 to 7, wherein each mask substrate and the first, second, and third information stored in correspondence with each other are presented to a container in which the mask substrate is accommodated. How to produce. For each of the plurality of mask substrates, each mask substrate is set in the exposure apparatus from first information indicating the surface shape of the main surface, and information about the flatness of the main surface measured by the measuring device and the structure of the mask chuck of the exposure apparatus. A process of acquiring second information representing the flatness of the main surface by simulation when The mask substrate information generation method characterized by presenting each mask substrate and said 1st information and 2nd information to the container which each mask substrate accommodates. 10. The method according to claim 9, further comprising the step of: storing the mask substrates, the first information, and the second information in association with each other; A method of generating mask substrate information, which is presented to a container in which a substrate is accommodated. 10. The mask substrate information generating method according to any one of claims 1 to 7, wherein a mask pattern is formed on a main surface of the mask substrate. The method of claim 11, wherein the mask pattern includes at least one of a circuit pattern and an alignment pattern. The mask substrate information generating method according to any one of claims 1 to 7, wherein a mark for position alignment is formed on the mask substrate in advance. The mask substrate information generating method according to any one of claims 1, 9, and 10, wherein the second information is obtained by the simulation using a finite element method. Preparing a mask substrate having a light shielding body formed on a quartz substrate; Acquiring first information indicating flatness of a main surface of the mask substrate; Obtaining second information indicating flatness of the main surface by simulation when the mask substrate is set in the exposure apparatus from the first information and information on the structure of the mask chuck of the exposure apparatus; A step of determining whether the flatness of the main surface of the mask substrate obtained by the simulation is within specification Method of manufacturing a mask substrate comprising a. Acquiring first information indicating flatness of the main surface of the mask substrate; Obtaining second information indicating flatness of the main surface by simulation when the mask substrate is set in the exposure apparatus from the first information and information on the structure of the mask chuck of the exposure apparatus; Determining whether the flatness of the main surface of the mask substrate obtained by the simulation meets the specification; And when it is determined that the flatness of the mask substrate does not meet the specification, the light shielding body on the main surface of the mask substrate is peeled off, and a new light shielding body is formed on the main surface of the substrate. Acquiring first information indicating flatness of the main surface of the mask substrate; Obtaining second information indicating flatness of the main surface by simulation when the mask substrate is set in the exposure apparatus from the first information and information on the structure of the mask chuck of the exposure apparatus; Determining whether the flatness of the main surface of the mask substrate obtained by the simulation meets the specification; If it is determined that the flatness of the mask substrate does not meet specifications, the light shielding body on the main surface of the mask substrate is peeled off, and after the main surface of the substrate is polished, a new light shielding body is formed on the main surface of the substrate. The manufacturing method of the mask substrate made into. The mask substrate information generation according to any one of claims 1, 2, 3, and 5, wherein the flatness is any one of a surface shape, a flatness, or a surface shape and a flatness. Way. The method of manufacturing a mask substrate according to any one of claims 15 to 17, wherein the flatness is any one of a surface shape, a flatness, or a surface shape and a flatness.