JPH09106937A - Mask manufacturing method, mask structure formed using the method, exposure apparatus using the mask structure, device manufacturing method, and device manufactured thereby - Google Patents

Abstract

(57) Abstract: An X-ray mask structure in which flatness is sufficiently controlled and a highly precise positional accuracy of a pattern is secured, and a manufacturing method thereof. In the manufacturing process of an X-ray mask structure including an X-ray absorber, a support film that supports the absorber, and a holding frame that holds the support film (a reinforcing body may be attached), The flatness is controlled by using a substrate that serves as a holding frame having a warpage equal to the difference in flatness that occurs in the process (in particular, before and after etching the holding frame).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mask structure and a manufacturing method thereof, and further relates to an X-ray exposure apparatus and a device manufacturing method using the mask structure.

[0002]

2. Description of the Related Art In recent years, with the increase in density and speed of semiconductor integrated circuits, the pattern line width of integrated circuits has been reduced, and semiconductor manufacturing methods are required to have higher performance. Therefore, a high precision etching technique and a stepper using a light in the X-ray region (2 to 20Å) for the exposure wavelength are being developed as a printing apparatus.

FIG. 2 shows a schematic diagram of a method of exposing and transferring onto a wafer by such an X-ray exposure apparatus.

The radiant light B emitted from the SR radiation source A is
The light is reflected and enlarged by the convex mirror C, the exposure amount is adjusted by the shutter D, the light is guided to the X-ray mask E as described above, and the pattern is transferred onto the wafer F.

In the above-mentioned transfer, in order to perform the transfer with high accuracy, the gap between the X-ray mask E and the wafer F is set to several to several.
It is necessary to control to several tens of μm. Therefore, highly accurate flatness control is required for the X-ray mask.

The X-ray mask structure used in this X-ray exposure apparatus has a structure as shown in FIG. X-ray absorber 13, support film 12 supporting the absorber 13, support film 1
It comprises a holding frame 11 for holding 2. The holding frame 11 may be provided with the reinforcing body 14 in some cases.

By the way, the support film 12 needs to have a thickness of about 1 to 2 μm in order to obtain a sufficient X-ray transmittance, and it is necessary to impart a tensile stress so that the film does not sag. , The stress causes a warp in the holding frame 11,
That made it difficult to control the flatness of the X-ray mask.

In order to control the flatness of the X-ray mask, Japanese Unexamined Patent Publication No. 60-251620 discloses a method of forming a recess at the outer edge of the holding frame with respect to the pattern forming surface of the support film as shown in FIG. Line masks have been proposed. However, this publication does not consider the warpage due to the stress of the supporting film,
By forming the concave portion in the holding frame, the rigidity of the holding frame was lowered, and the effect of improving the flatness was not sufficient.

Further, Japanese Patent Application Laid-Open No. 4-335515 proposes flatness control by making the holding frame thin and making the reinforcing body highly rigid. However, the thinner the holding frame, the greater the amount of deflection due to the same stress.Therefore, the amount of change in the flatness of the holding frame and the supporting film at the time of mounting the reinforcement is large, and the supporting film and the holding frame may be damaged. It was

Further, it is very complicated to carry out the process of processing the absorbent body after mounting the reinforcing body on the holding frame. However, when the reinforcing body is mounted after forming the absorbent body, the flatness is not controlled. In the holding frame, the absorber is displaced during mounting, and it is difficult to form a high-precision X-ray mask.

[0011]

SUMMARY OF THE INVENTION The present invention solves the problems of the prior art described above, and provides a mask manufacturing method and a manufacturing method thereof in which the flatness is sufficiently controlled and a highly precise pattern positional accuracy is ensured. An object of the present invention is to provide a mask structure manufactured by using the mask structure, an exposure apparatus using the mask structure, a device manufacturing method for manufacturing using the mask structure, and a device manufactured by the method.

[0012]

The above objects are achieved by the present invention described below.

The first aspect of the present invention includes a step of preparing a non-planar substrate on which a thin film to be a pattern support film is formed, the convex surface side of the non-planar substrate being a pattern forming surface, and the back surface side being etched. A mask manufacturing method characterized by the above. The first invention may further include a step of forming a pattern of the radiation absorber on the support film serving as the pattern forming surface, and in that case, the radiation absorber includes an X-ray absorber and the like. Further, in the first invention and each of the above-described embodiments, the substrate has a predetermined warp amount in advance within a range of ± 3 μm with respect to a change amount of the warp amount before and after etching. There is a further preferred embodiment.

A second aspect of the present invention is a mask structure produced by the manufacturing method according to the first aspect of the present invention and the above embodiments.

A third invention is an exposure apparatus characterized in that it has means for holding the mask structure of the second invention and means for exposing the mask structure.

A fourth aspect of the invention is a device production method characterized in that a device is produced using the mask structure of the second aspect.

A fifth aspect of the invention is a device characterized by being produced by the production method of the fourth aspect.

When the X-ray absorber can be controlled to a very small internal stress, or when the absorber has a small area, it does not affect the flatness of the mask when the absorber is formed on the support film. Therefore, after the support film is formed, the difference in the flatness of the holding frame that holds the support film before and after the etching step is measured in advance, and the degree of the flatness of the convex on the pattern forming surface side (the convex surface side) is measured. Prepare a non-planar substrate that is approximately the same as the difference in flatness (preferably in the range of ± 3 μm),
By using the convex surface side of the non-planar substrate as the pattern forming surface and etching the back surface side, the flatness of the obtained mask can be controlled. On the other hand, when the internal stress of the absorber is large, it depends on the area. Since it affects the flatness of the mask, the difference in flatness that occurs in all steps of manufacturing the mask is measured in advance, and the degree of flatness of the convex on the pattern formation surface side (convex side) is A non-planar substrate having a difference about the same (preferably within a range of ± 3 μm) is prepared, the convex side of the non-planar substrate is used as a pattern forming surface, and the back side is etched to obtain the plane of the mask. Degree control can be performed.

When the reinforcing body can be joined to the holding frame without applying force, the reinforcing body may be joined and then etched, or the reinforcing body may be joined after etching and absorber formation. , It is not necessary to consider the warpage of the substrate caused by the joining of the reinforcements, but if the substrate warpage occurs due to the force at the time of joining the reinforcements, take it into consideration and form a holding frame including the reinforcements. The degree of flatness of the convex on the side of the pattern formation surface of the substrate should be almost the same as the difference in flatness (preferredly within a range of ± 3 μm) that is measured before and after the etching process of the holding frame after forming the support film. Or
The difference in flatness that is generated in all steps measured in advance is approximately the same (preferably within a range of ± 3 μm).

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The operation of the present invention will be described.
By the X-ray mask structure and the manufacturing method thereof, even if the tensile stress of the support film or the internal stress of the absorber is applied to the holding frame, the flatness is controlled without applying an unreasonable force to the holding frame. It is possible to obtain an X-ray mask that can ensure highly accurate position accuracy. Further, since the reinforcing body can be attached after the absorber is formed, the manufacturing process of the X-ray mask becomes easy.

Further, by using the X-ray mask having good flatness, the gap during X-ray exposure can be controlled with high accuracy, and the in-plane accuracy during X-ray exposure and the throughput are improved. Furthermore, defects and damages caused by dust are reduced.

Next, the present invention will be described in detail with reference to preferred embodiments.

First, the X-ray supporting film transmits X-rays sufficiently,
1 to 10 μm because it is necessary to be self-standing
It is preferable to make the thickness within the range of, and those having tensile stress, for example, Si, SiO ₂ , SiN, SiC, Si
It is selected from known materials such as an inorganic film such as CN, BN, a radiation resistant organic film such as polyimide, and a single film or a composite film of these. Next, the X-ray absorber needs to absorb X-rays sufficiently and have good workability.
The thickness is preferably in the range of 1.0 μm to 1.0 μm, and is composed of, for example, heavy metals such as Au, W, Ta and Pt, and further compounds thereof. Further, the holding frame for holding the X-ray supporting film is made of a silicon wafer or the like, and may be an ordinary flat substrate or may have a shape having a recess as shown in FIG. A substrate having a flatness (convex toward the pattern forming surface) equivalent to the difference in flatness generated in all the steps (especially before and after etching the holding frame) is used. Normally, a substrate having parallelism has a concave surface on the back surface, but both surfaces may have a convex shape. Further, the holding frame may be provided with a reinforcing member for assisting transportation of the X-ray mask structure, and the reinforcing member is made of Pyrex glass, Si, T or the like.
It is made of a material such as ceramics such as i, SiC and SiN. In addition to this, the X-ray mask structure of the present invention may be provided with a protective film for the X-ray absorber, a conductive film, an anti-reflection film for alignment light, and the like, if necessary.

Such an X-ray mask structure is manufactured by the following steps. First, a supporting film is formed on a silicon wafer which will be a holding frame. When the support film is formed by CVD, it is formed on both sides, so the X-ray transparent portion of the film on the back surface is etched to form an etching protection film for the holding frame. When the support film is formed by sputtering or the like, it is formed on only one surface, so the same film may be formed on the back surface as the etching protective film of the holding frame, or another protective film having high etching resistance may be used. .

The silicon wafer serving as the holding frame is etched using a strong alkali (eg, 30 wt% KOH) or a hydrazine-pyrocatechol solution. The flatness before and after the etching is measured by using a laser interferometer or the like, and the difference in the flatness caused by the etching is obtained. And
A silicon wafer having a warp equivalent to this difference in flatness (the degree of flatness of the convex on the pattern formation surface has a value of the difference in flatness determined by measurement ± 3 μm) is prepared by polishing. . At this time, by slightly increasing the amount of warpage due to polishing, the shape of the holding frame of the final X-ray mask may be higher at the inner edge than at the outer edge, as shown in FIG. If the difference in flatness caused by etching is as small as a few μm or less, a product with the desired warpage can be obtained by selecting from commercially available silicon wafers without intentionally making it by polishing. You can also get

The reinforcing body may be joined to the holding frame before or after etching. The formation of the absorber is similar. In particular, in the present invention, it is also possible to attach the reinforcing body after forming the absorber on the support film. An adhesive may or may not be used to attach the reinforcing body. Epoxy adhesive,
Although there are rubber type and acrylic type, those which can be bonded at room temperature such as room temperature curing type or light curing type are preferable. Further, there are direct bonding, anodic bonding, etc. for bonding without using an adhesive, but it is preferable to bond at low temperature by using light at the time of bonding or using a monomolecular accumulated film between bonding substrates. .

The X-ray exposure method and X-ray exposure apparatus of the present invention are characterized by using the X-ray mask structure of the present invention. That is, the X-ray exposure method of the present invention is
The semiconductor device and the semiconductor device of the present invention are characterized in that the X-ray absorber pattern is transferred to the transfer target by performing X-ray exposure on the transfer target via the X-ray mask structure. The manufacturing method is manufactured by exposing the processed substrate to X-rays through the X-ray mask structure, transferring the X-ray absorber pattern onto the processed substrate, and processing and forming the pattern. Is a device.

The X-ray exposure method and X-ray exposure apparatus of the present invention may be any conventionally known method except that the X-ray mask structure of the present invention is used, and the semiconductor device and semiconductor device manufacturing method of the present invention. Also in the method, the device is manufactured by a conventionally known method except that the X-ray mask structure of the present invention is used.

[0029]

The present invention will be described in more detail by way of examples with reference to the drawings.

Example 1 FIG. 1 is a cross-sectional view of the manufacturing process of an X-ray mask structure according to the present invention.

On the 3 inch Si substrate 11a which is made of the same material and has the same thickness (2 mmt in this embodiment) as the 3 inch Si substrate which finally becomes the holding frame 11, an X-ray transparent film 12 in the figure is formed. A supporting film 12a was formed by CVD under the same conditions as when SiN 2.0 μm used as a supporting film was provided (state shown in FIG. 1A).

The flatness of the substrate was measured with a high precision laser interferometer ZYGO MARK-IV XP (manufactured by Canon).

Next, a portion of the back surface 12a of the Si substrate 11a corresponding to the X-ray transmission region (30 mm □ in this embodiment).
Is dry-etched, and the Si substrate 11a is
Etching was performed with t% KOH to obtain the state shown in FIG.

The flatness at that time was measured again by the high precision laser interferometer ZYGO MARK-IV XP, and FIG.
And the difference in flatness δ ₁ between (b) was obtained. In this example, δ ₁
= 4.3 μm. In FIG. 1, the substrate of FIG. 1 (a) is illustrated so as not to have a warp, but the substrate of FIG. 1 (a) may have a warp and the flatness difference between it and (b) may be obtained. .

A warpage equivalent to δ ₁ (degree of warpage is 4.3 ±
A 3-inch Si substrate (2 mmt) having a range of 3 μm is prepared. In the case of this example, since δ ₁ is small, the flatness was measured and selected from the commercially available substrates.
This substrate is designated as 11, and SiN 2.0 μm is deposited on this substrate as 12
The support film 12 was formed by CVD under the same conditions as in the case of a (the state of FIG. 1C). Support film 12 is 7.0 × 10
^It has a tensile stress of ⁸ dyn / cm ² , but does not affect the flatness when formed on both sides.

In the same manner as 11a and 12a, the support film 12 on the back surface side and the portion 11 to be the holding frame were etched in order at the portion corresponding to the X-ray transmission region to obtain the state of FIG. 1 (d).
When the flatness was measured again, it was 1 μm or less.

Au is used as the X-ray absorber 13 in an amount of 0.35 μm.
It was formed to a thickness by plating to obtain the state shown in FIG. Au of the absorber did not affect the flatness because it could control a very small stress.

Furthermore, by using an epoxy adhesive without applying force to the SiC reinforcement 14, the holding frame 1
1 and the state shown in FIG.

In the X-ray mask manufactured by the above-mentioned method, the reinforcing body is mounted at the end, so that the X-ray mask can be formed in good yield without passing through a complicated process.
Further, the flatness could be maintained at 1 μm or less without applying an excessive force. Therefore, it was possible to manufacture a highly accurate X-ray mask that highly secured the positional accuracy of the absorber.

Example 2 This example was made much like Example 1 except that Si
A substrate having a thickness of 0.4 mmt was used.

The flatness of this example was measured by a high precision laser interferometer ZYGO MARK-IV XP in the same manner as in Example 1 to obtain the difference δ ₂ between the flatnesses of FIGS. 1 (a) and 1 (b). In this example, δ ₂ = 50 μm.

A warpage equivalent to δ ₂ (degree of warpage is 50 ± 3
3 inch Si substrate (0.4 mmt) with a range of μm)
Prepare The Si substrate is polished so as to have such a warp. An X-ray mask was produced in the same manner as in Example 1 using such a substrate. The flatness was 3 μm or less.

In the X-ray mask manufactured by the above method, since the reinforcing body is mounted at the end, a normal wafer process can be substituted without passing through a complicated process, and the X-ray mask can be manufactured with high yield. Could be formed. Further, the flatness could be maintained at 3 μm or less without applying excessive force. Therefore, it was possible to manufacture a highly accurate X-ray mask capable of ensuring a high positional accuracy of the absorber.

Embodiment 3 FIG. 3 is a sectional view of the manufacturing process of this embodiment of the X-ray mask structure according to the present invention.

An X-ray transparent film 32 in the figure is formed on a 4-inch Si substrate 31a which is made of the same material and has the same thickness (2 mmt in the present embodiment) as the 4-inch Si substrate which finally becomes the holding frame 31. A support film 32a was formed by CVD under the same conditions as when SiC 2.0 μm used as a support film was provided, and the state shown in FIG. 3A was obtained. For the holding frame of this example, a Si substrate having a recess at the outer edge was used.

Next, 0.7 μmt of W is formed into a film by sputtering under the same conditions as when forming the film of the X-ray absorber 33 later, and the film is etched into a desired pattern to obtain the state of FIG. did. The stress of W is a tensile stress of 1.0 × 10 ⁹ dyn /
Since it is cm ^2, the flatness may be affected depending on the area of the absorber.

High-precision laser interferometer ZYGO MARK-IV XP (made by Canon)
Was measured.

Next, a portion of the back surface 32a of the Si substrate 31a corresponding to the X-ray transmission region (50 mm □ in this embodiment).
Is dry-etched, and the Si substrate 31a is further etched with a pyrocatechol-ethylenediamine solution.
The state of (c) was adopted.

The flatness at that time was measured again by the high precision laser interferometer ZYGO MARK-IV XP, and FIG.
And the difference in flatness δ ₃ between (c) was obtained. In this example, δ ₃
= 5.0 μm.

After forming the absorber, a 4-inch Si substrate (2 mmt) having a concave portion at its outer edge portion is prepared so as to have a warp equivalent to δ ₃ (the warp degree is in the range of 5.0 ± 3 μm). If the absorber has a small area and does not affect the flatness, prepare a substrate having a warpage equal to δ ₃ . When it is necessary to consider the influence of the absorber, the difference in flatness between FIGS. 3A and 3C is obtained, and the amount of warp of the Si substrate to be prepared is determined. Taking this into consideration, this time, the substrate was made by polishing together with the concave portion of the outer edge.

This substrate is designated as 31, and SiC2.
A film having a thickness of 0 μm was formed by CVD under the same conditions as 32a to form a support film 32, and the state shown in FIG. 3D was obtained. Support film 32
Has a tensile stress of 1.0 × 10 ⁹ dyn / cm ² ,
When it is formed on both sides, it does not affect the flatness.
As the X-ray absorber 33, W having a thickness of 0.7 μm was formed by the same method as that of 33a, and the state shown in FIG. The warp amount of this substrate is δ ₃ .

In the same manner as 31a and 32a, the supporting film 32 and the holding frame 31 were etched to obtain the state shown in FIG. 3 (f). When the flatness was measured again, it was 2 μm or less.

Further, by using an epoxy adhesive without applying force to the SiC reinforcing member 34, the holding frame 3
1 and the state shown in FIG.

In the X-ray mask manufactured by the above-mentioned method, the reinforcing body is mounted at the end, so that the X-ray mask can be formed with a good yield without passing through a complicated process.
In addition to controlling the warpage of the substrate, by forming a recess in the outer edge, the flatness of 2μ can be achieved without applying excessive force.
It could be maintained below m. Therefore, it was possible to manufacture a highly accurate X-ray mask capable of ensuring a high positional accuracy of the absorber.

Embodiment 4 FIG. 4 is a sectional view of the manufacturing process of this embodiment of the X-ray mask structure according to the present invention.

On the 3 inch Si substrate 41a which is made of the same material and has the same thickness (1 mmt in this embodiment) as the 3 inch Si substrate which finally becomes the holding frame 41, an X-ray transparent film 42 in the figure is formed. A supporting film 42a was formed by CVD under the same conditions as when providing SiN 2.0 μm used as a supporting film to form the state shown in FIG.

Next, the same material 44a as the reinforcing body 44 made of Pyrex glass was bonded to the Si substrate 41a by anodic bonding to obtain the state shown in FIG. 4 (b).

The flatness of the substrate was measured with a high precision laser interferometer ZYGO MARK-IV XP (manufactured by Canon).

Next, a portion of the back surface 42a of the Si substrate 41a corresponding to the X-ray transmission region (35 mm □ in this embodiment).
Is dry-etched to protect the reinforcement 44,
The i substrate 41a was etched with a 30 wt% KOH solution to obtain the state of FIG.

The flatness at that time was measured again by the high precision laser interferometer ZYGO MARK-IV XP, and FIG.
And the difference in flatness δ ₄ between (c) was obtained. In this example, δ ₄
= 2.3 μm.

A 3-inch Si substrate (1.0 mmt) is prepared so as to have a warp equivalent to δ ₄ (the degree of warpage is in the range of 2.3 ± 3 μm) after being joined to the reinforcing member 44. That is,
Although the Si substrate is polished so as to have such a warp, in reality, the difference in flatness between the flat body of FIGS. Then, the difference was added and the amount of warpage of the Si substrate to be prepared was determined and prepared by polishing. This substrate is designated as 41, on which SiN
The support film 4 is formed by forming a film of 2.0 μm under the same conditions as the case of 42a.
2 was formed and the state shown in FIG. The support film 42 has a tensile stress of 5.0 × 10 ⁸ dyn / cm ² , but when it is formed on both sides, it does not affect the flatness.

A reinforcing member 44 made of Pyrex was joined to 41 by anodic bonding in the same manner as in 44a, and
The state of (e) was adopted. The warpage of the joined substrates is δ ₄ .

The supporting film 42 and the holding frame 41 were etched in the same manner as 41a and 42a to obtain the state shown in FIG. 4 (f). When the flatness was measured again, it was 1 μm or less.

As the X-ray absorber 43, Au 0.7 μm thick was formed by plating to obtain the state shown in FIG. 4 (g). Au of the absorber did not affect the flatness because it could control a very small stress.

The X-ray mask manufactured by the above method was able to maintain the flatness of 1 μm or less without applying excessive force. Therefore, it was possible to manufacture a highly accurate X-ray mask capable of ensuring a high positional accuracy of the absorber.

Embodiment 5 FIG. 5 is a cross-sectional view of the manufacturing process of this embodiment of the X-ray mask structure of the present invention.

On the 3 inch Si substrate 51a which is made of the same material and has the same thickness (2 mmt in this embodiment) as the 3 inch Si substrate which will be the holding frame 51 in the end, an X-ray transmission film 52 in the figure is formed. A supporting film 52a was formed by CVD under the same conditions as when providing 2.0 μm of SiN used as a supporting film, and the state shown in FIG. 5A was obtained.

Next, the same reinforcing member 54a made of Si is directly bonded to the Si substrate 51a as shown in FIG.
The state of (b) was adopted. At the time of joining, SiN on the back surface may be peeled off using hot phosphoric acid or the like.

The flatness of the substrate was measured with a high precision laser interferometer ZYGO MARK-IV XP (manufactured by Canon). Next, a portion of the back surface 52a of the Si substrate 51a corresponding to the X-ray transmission region (25 mm □ in this embodiment) is dry-etched, and the Si substrate 51a is etched with a 30 wt% KOH solution while protecting the reinforcing member 54. , Fig. 5
The state of (c) was adopted.

The flatness at that time was measured again by the high precision laser interferometer ZYGO MARK-IV XP, and FIG.
A difference δ ₅₀ between the flatnesses of (c) and (c) was obtained. In this example, δ ₅₀
= 3.2 μm.

Under the same conditions as when the X-ray absorber 53 is provided, 0.7 μmt of Ta is deposited by sputtering and etched into a desired pattern to obtain the state of FIG. 3 (d). Ta
The compressive stress is 1.0 × 10 ⁹ dyn / cm ² , and therefore the flatness may be affected depending on the area of the absorber.

The flatness of the substrate was measured with a high precision laser interferometer ZYGO MARK-IV XP, and FIG.
The difference δ ₅₁ between (d) and (d) was determined. In this embodiment, δ ₅₁ = 2.1
μm.

A 3-inch Si substrate (2.0 mmt) is prepared so as to have a warp similar to δ ₅₁ (the degree of warpage is in the range of 2.1 ± 3 μm) after being joined to the reinforcing body 54. That is,
The Si substrate is polished so as to have such a warp, but in reality, the difference in flatness between the flat body shown in FIGS. Then, the difference was added and the amount of warpage of the Si substrate to be prepared was determined and prepared by polishing. This substrate is designated as 51, on which SiN
A film having a thickness of 2.0 μm was formed in the same manner as in the case of 52a to form a supporting film 52, and the state shown in FIG. The support film 52 has a tensile stress of 5.0 × 10 ⁸ dyn / cm ² , but does not affect the flatness when formed on both sides.

The reinforcing body 54 made of Pyrex is directly joined to 51 by the same method as that of 54a.
The state of (f) was adopted. The warpage of the bonded substrates is δ ₅₁ .

The support film 52 and the holding frame 51 were etched in the same manner as 51a and 52a to obtain the state shown in FIG. 5 (g). The warpage of the substrate is δ ₅₀ −δ ₅₁ .

A 0.7 μm thick Ta film was formed as the X-ray absorber 53, and the state shown in FIG. When the flatness was measured again, it was 1 μm or less.

The X-ray mask manufactured by the above method was able to maintain the flatness of 1 μm or less without applying excessive force. Therefore, it was possible to manufacture a highly accurate X-ray mask capable of ensuring a high positional accuracy of the absorber.

Embodiment 6 FIG. 6 is a cross-sectional view of the manufacturing process of this embodiment of the X-ray mask structure of the present invention.

On the 4 inch Si substrate 61a which is made of the same material and has the same thickness (5 mmt in this embodiment) as the 4 inch Si substrate which finally becomes the holding frame 61, an X-ray transmission film 62 in the figure is formed. A supporting film 62a was formed by CVD under the same conditions as when providing SiN 2.0 μm used as a supporting film, and the state shown in FIG. 6A was obtained.

The flatness of the substrate was measured with a high precision laser interferometer ZYGO MARK-IV XP (manufactured by Canon).

Next, a portion of the back side 62a of the Si substrate 61a corresponding to the X-ray transmission region (45 mm □ in this embodiment).
Is dry-etched, and the Si substrate 61a is further 30 w
Etching was performed with a t% KOH solution to obtain the state shown in FIG.

The flatness at that time was measured again by the high precision laser interferometer ZYGO MARK-IV XP, and FIG.
And the flatness difference δ ₆ between (b) were obtained. In this embodiment, δ ₆ =
It was 1.8 μm.

A warpage similar to δ ₆ (degree of warpage is 1.8 ±
A 4-inch Si substrate (5 mmt) having a range of 3 μm is prepared. This time, the flatness was measured and selected from the substrates that are usually on the market. This substrate was set to 61, and SiN 2.0 μm was formed thereon under the same conditions as in the case of 62a to form the support film 62, and the state shown in FIG. 6C was obtained. Support membrane 6
2 has a tensile stress of 8.0 × 10 ⁸ dyn / cm ² , but does not affect the flatness when it is formed on both sides.

The support film 62 and the holding frame 61 were etched in the same manner as 61a and 62a to obtain the state shown in FIG. 6 (d). When the flatness was measured again, it was 1 μm or less.

Au is used as the X-ray absorber 63 in an amount of 0.35 μm.
It was formed by plating to a thickness to obtain the state shown in FIG. Au of the absorber did not affect the flatness because it could control a very small stress.

Since the X-ray mask manufactured by the above method does not use a reinforcing body, the X-ray mask could be formed with a good yield without passing through a complicated process. Further, the flatness could be maintained at 1 μm or less without applying an excessive force. Therefore, it was possible to manufacture a highly accurate X-ray mask capable of ensuring a high positional accuracy of the absorber.

Embodiment 7 Next, an embodiment of an exposure apparatus for manufacturing microdevices (semiconductor devices, thin film magnetic heads, micromachines, etc.) using the mask described in Embodiments 1 to 6 will be described. FIG. 2 is a view showing the arrangement of the X-ray exposure apparatus according to this embodiment. SR in the figure
The sheet-beam-shaped synchrotron radiation B emitted from the radiation source A is expanded by the convex mirror C in the direction perpendicular to the orbital plane of the radiation. The emitted light reflected and expanded by the convex mirror C is adjusted by the shutter D so that the exposure amount in the irradiation area becomes uniform, and the emitted light that has passed through the shutter D is guided to the X-ray mask E. The X-ray mask E is manufactured by the method described in any of the embodiments described above. The exposure pattern formed on the X-ray mask E is exposed and transferred onto the wafer F by a step & repeat method, a scanning method, or the like. By using an X-ray mask having good flatness, the gap during X-ray exposure can be controlled with high accuracy, and the in-plane accuracy and throughput during X-ray exposure are improved. Also, defects and damages caused by dust could be reduced.

Example 8 Next, an example of a method of manufacturing a semiconductor device using the above-described X-ray mask structure will be described. FIG. 7 is a flowchart showing a manufacturing flow of semiconductor devices (semiconductor chips such as IC and LSI, liquid crystal panels, CCDs, thin film magnetic heads, microsyringes, etc.). In step 1 (circuit design), the circuit of the semiconductor device is designed. In step 2 (mask manufacturing), the X-ray mask structure having the designed circuit pattern is manufactured by using the method of Examples 1 to 6. On the other hand, in step 3 (wafer manufacturing), a wafer is manufactured using a material such as silicon. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by the X-ray lithography technique using the X-ray mask structure and the wafer prepared above. The next step 5 (assembly) is called a post-process, and is a process of forming a semiconductor chip using the wafer manufactured in step 4, such as an assembly process (dicing, bonding), a packaging process (chip encapsulation), etc. including. In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device created in step 5 are performed. Through these steps, the semiconductor device is completed,
This is shipped (step 7).

FIG. 8 shows a detailed flow of the wafer process. In step 11 (oxidation), the surface of the wafer is oxidized. In step 12 (CVD), an insulating film is formed on the wafer surface. In step 13 (electrode formation), electrodes are formed on the wafer by vapor deposition. In step 14 (ion implantation), ions are implanted in the wafer. Step 15
In (resist processing), a photosensitive agent is applied to the wafer. In step 16 (exposure), the circuit pattern of the mask is printed and exposed on the wafer by the X-ray exposure method described above. In step 17 (development), the exposed wafer is developed. In step 18 (etching), portions other than the developed resist image are removed. In step 19 (resist stripping), the resist that is no longer needed after etching is removed.
By repeating these steps, multiple circuit patterns are formed on the wafer.

By using the manufacturing method of the present invention, it is possible to manufacture a highly integrated semiconductor device which has been difficult to manufacture in the past.

Further, in the device produced by X-ray exposure using these X-ray mask structures, a pattern faithful to the device design drawing can be produced. It can be integrated and has good device characteristics.

[0092]

INDUSTRIAL APPLICABILITY In the process of manufacturing an X-ray mask structure comprising an X-ray absorber, a support film for supporting the absorber, and a holding frame for holding the support film (a reinforcing body may be additionally provided), By performing flatness control using a substrate that becomes a holding frame having a flatness equal to the difference in flatness that occurs in all processes (especially before and after etching the holding frame), the tensile stress of the support film and the absorber Even if stress is applied to the holding frame, the flatness is controlled without exerting an unreasonable force on the holding frame, and thus a mask that can secure highly accurate position accuracy can be obtained. Further, since the positional displacement of the absorber due to the mounting of the reinforcing body hardly occurs, it is possible to mount the reinforcing body after the absorbent body is formed, which facilitates the mask manufacturing process.

Further, in the X-ray exposure method and the X-ray exposure apparatus using the mask having good flatness of the present invention, the gap during X-ray exposure can be controlled with high accuracy, and the in-plane during X-ray exposure can be controlled. The accuracy and throughput are improved, and the defects and damages due to dust are reduced, so that it is possible to provide a high-precision X-ray exposure method and an X-ray exposure apparatus.

Further, the X-ray exposure method using the X-ray mask having a good flatness of the present invention and the X-ray absorption pattern are transferred onto the processed substrate by the X-ray exposure apparatus, processed, formed and produced. A high performance semiconductor device and a semiconductor device manufacturing method can be provided.

[Brief description of the drawings]

FIG. 1 shows a manufacturing process ((a) → (f) is each process) of the X-ray mask structure of the present invention shown in Example 1.

FIG. 2 is a simplified diagram of the X-ray exposure apparatus of the present invention.

FIG. 3 shows a manufacturing process ((a) → (g) is each process) of the X-ray mask structure of the present invention shown in Example 3.

FIG. 4 shows a manufacturing process ((a) → (g) is each process) of the X-ray mask structure of the present invention shown in Example 4.

FIG. 5 shows a manufacturing process ((a) → (h) is each process) of the X-ray mask structure of the present invention shown in Example 5.

FIG. 6 shows a manufacturing process ((a) → (e) is each process) of the X-ray mask structure of the present invention shown in Example 6.

FIG. 7 is a manufacturing flow of a semiconductor device used in the present invention.

FIG. 8 is a flow chart of a wafer process used in the present invention.

FIG. 9 shows a conventional X-ray mask structure.

FIG. 10 shows a state of the holding frame of the X-ray mask in which the inner edge is higher than the outer edge.

[Explanation of symbols]

11, 11a, 31, 31a, 41, 41a, 51, 5
1a, 61, 61a holding frame 12, 12a, 32, 32a, 42, 42a, 52, 5
2a, 62, 62a Support film 13, 33, 33a, 43, 53, 53a, 63 X
Line absorber 14, 34, 44, 44a, 54, 54a Reinforcer A Window port B Mask chuck C Alignment detector D X-ray mask E Exposed object F Wafer chuck G Chamber

Claims (8)

[Claims] 1. A step of preparing a non-planar substrate on which a thin film to be a pattern support film is formed, the convex side of the non-planar substrate being a pattern forming surface, and the back side being etched. Mask manufacturing method. 2. The mask manufacturing method according to claim 1, further comprising the step of forming a pattern of a radiation absorber on a support film which becomes a pattern forming surface. 3. The mask manufacturing method according to claim 2, wherein the radiation absorber is an X-ray absorber. 4. The mask according to claim 1, wherein the substrate has a predetermined warp amount within a range of ± 3 μm with respect to a change amount of the warp amount before and after etching. Production method. 5. A mask structure manufactured by using the manufacturing method according to claim 1. 6. An exposure apparatus comprising: a means for holding the mask structure according to claim 5; and a means for exposing the mask structure. 7. A device manufacturing method comprising manufacturing a device using the mask structure according to claim 5. 8. A device produced by the production method according to claim 7.