JPS5882522A - X-ray exposure mask and manufacture thereof - Google Patents

Abstract

PURPOSE:To remarkably reduce the warpage of the whole part of a mask by a method wherein a transfer pattern supporting layer having a region with a little contribution to the adherence of a laminated layer is eliminated. CONSTITUTION:SiO2 films 2, 2' are formed on an Si single crystalline substrate 1, and an Si3N4 film 3 is formed on either one of the surfaces. Next, the film 3 is etched and removed to form a film 3' and the films 2, 2' are eliminated by using the film 3' as a mask and an SiO2 film 2'' and an opening portion 4 are formed. Next, the film 2 is eliminated to form a transfer pattern supporting layer 5 on the exposed substrate 1. Then, the part except the region corresponding to the opening portion 4 of the layer 5 is eliminated to form a supporting layer 5' and an opening region 8. A transfer patten 9 is formed on the surface of the layer 5', while Si is epitaxially grown in the opening 8 to form spacers 10. Next, the opening portion 4 is etched and removed to form reinforcement supporting beams 1' formed by a part of the substrate 1 and a transfer pattern region 11. In this structure, the warpage of the whole part of a mask can remarkably be reduced by eliminating the predetermined region of the layer 5.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an X-ray exposure mask and a method for manufacturing the same.

The X-ray exposure method can best demonstrate its lk geometry at 1 μt.
This is the case in the transfer process of extremely fine patterns having a line width of nslt& or less.

And X-ray exposure! The fabric is required to meet various conditions such as high contrast against soft X-rays, low coefficient of thermal expansion, transparency against visible light, high flatness, high pitch precision, and chemical resistance.

Conventionally, as a practical X-ray exposure mask that generally satisfies the above conditions, 5-N4 and 8i0. A composite transparent film with a three-layer structure sandwiching the film is supported by reinforcing support beams made of silicon (hereinafter abbreviated as S1) phosphorus crystal, and the composite transparent film serves as a transfer pattern support layer (hereinafter simply referred to as a three-layer structure). structure) is known. However, this is not limited to the X-ray exposure mask with the three-layer structure described above; for example, there may be one in which a B-doped 81oP+ diffusion layer is used as a pattern support layer, or an 81. N4 and sio.

In general, a two-layer structure such as %S"! has a structure in which a patterned support layer with tensile stress is integrated and fixed on the entire surface of a reinforcing support beam made of crystal using a layered growth technique that does not require adhesives. xmg party black mask There is a drawback that the tension of the support layer itself causes creases in the entire transfer mask.If these creases line up, they increase the amount of geometric positional deviation of the pattern to be transferred. The transcription of f.
t- has a negative influence on those who lower it.

Furthermore, when overlapping exposure is performed using multiple X-ray exposure masks, if the opposite side of each X-ray exposure mask substrate is stronger than the other, the mutual positional deviation of the patterns transferred with each mask will be reduced. Although this can be ignored, in reality, it is common for the patterns to be reversed in different ways, and the mutual positional deviation of the patterns has a serious effect.

As a specific example of the X-ray exposure conditions, consider a case where the distance between the X-ray source and the X-ray exposure mask is 300 m, and the distance between the outermost pattern to be transferred to the wafer and the center of the wafer is 300 m. The amount of geometric positional deviation Δ of the transferred pattern is
Assuming that the distance between the line exposure mask and the wafer is 62m, Δ-
d/xO.

Therefore, the amount of positional deviation between the transferred patterns is less than ±0.1 μm mgm, which is the minimum required for overlapping exposure of fine patterns with a minimum line width of 1/1 mo! In order to suppress Therefore, it is necessary to suppress the deviation to ±1 μm or less.

However, in an X-ray exposure mask with a conventional structure, approximately I
Since the transfer pattern support layer is formed with a tensile stress of 0' dynes/cd s*, no matter how many cross sections are taken, repulsion occurs such that the support layer side always becomes concave. In the case of a transfer mask with a diameter of 50 mm, a total of about 20 μm to 30 μm is generated], and even if vacuum suction is applied to a mask holder with good flatness, it is difficult to obtain the desired flatness. .

On the other hand, X-ray exposure masks that use a thin film made of an organic material such as polyethylene terephthalate, polyethylene terephthalate, or Kapton as a transfer pattern support layer can achieve higher flatness than those with the conventional structure; As a result, ±
It is extremely difficult to achieve alignment accuracy of 0.1 degrees.

The objects of the first and second inventions are to enable high-precision metal fitting using visible light, have excellent flatness, and have small pattern deviations;
The present invention has overcome nine problems that the conventional technology could not solve, such as having a coefficient of thermal expansion as low as 81 S* and realizing high chip density, and the present invention has created a harmful X-ray exposure mask and a method for manufacturing the same. It is about providing.

According to the first invention, in an xlI exposure mask comprising an X-ray transparent thin film having tensile stress and an 81 ratio crystal reinforced support beam supporting the scissors thin film, An X-ray exposure mask is obtained, characterized in that a portion of the X@transparent thin film is removed to provide an opening region, and a space made of Si is provided in the cough opening region.

According to the second invention, 8! on either surface of the 81m1 crystal substrate. A step of depositing either or both of a nitride film or an 8i oxide film, and etching away a desired region of these films to expose the surface of the 81$ crystal substrate; a step of depositing a KX-ray transparent layer on the narrow surface; forming and arranging a layer that absorbs both X-rays and visible light in a desired pattern on the transparent layer;

A step of etching away a predetermined region of the X-ray transparent layer to expose a part of the surface of the St single crystal substrate, and selectively epitaxially growing 81 on the exposed surface of the 5i single crystal substrate, and step #J. Then pattern it into the desired shape and apply 981 nitride film or S! A method for manufacturing an It will be done.

That is, the X-ray exposure mask and the method for manufacturing the same of the first and second inventions include forming a thin layer having tensile stress on the thorny surface of an 81$ crystal substrate so as to be laminated and fixed thereon, and applying this thin layer to a transfer pattern. A part of the B+ single crystal substrate is removed as a support layer, and the removed area is used as a transfer pattern area, and the remaining area of the sty crystal substrate is used as a reinforcing support beam for the transfer pattern support layer. None, a region of the transfer pattern support layer existing on the reinforcing support beam that makes a small contribution to the lamination adhesion is removed to expose the surface of the reinforcing support beam made of 8 i QL crystal, and the exposed reinforcing support beam is removed. A single crystal 8i with a thickness of 1 μm to 10#m was selectively grown on the beam by selective epitaxial growth method to serve as a spacer to maintain a constant distance between the line transfer pattern support layer and the surface of the substrate to be processed. It's a turtle.

Hereinafter, an example of the embodiment of the first and second inventions will be specifically explained with reference to the drawings. 1 and 2 are schematic cross-sectional views conceptually showing the structure in each manufacturing process by taking out a part of an X-ray exposure mask that is an embodiment of the second invention.

First, as shown in FIG. 1, a 19i$ bonded substrate 1 (0
On the surface, a thermal oxidation method is applied to form a layer with a thickness of several thousand amps to IJim.
10. 2 and 21 are formed, and 8'sNa[II3 having a thickness of 100 to several thousand AO is formed on the narrow surface of either one of the 810° films by CVD. This surface does not necessarily have to be a mirror surface.

Next, a resist pattern formed by patterning using a normal optical exposure method or the like is used as a protective film.

Part of #8isNa@a is etched away by plasma etching or the like to form 3', and then the 8i0. All of @2 and 2°
After forming an opening 4 for etching away a portion of the Si-content crystal substrate, the resist pattern is removed to obtain the state shown in FIG. 2.

Thereafter, as shown in FIG. 3, the Si nitride film, carbide, and boron nitride, for example, are deposited on the mirror surface of the Si$crystal substrate 1, which is exposed by removing the Si film 2.

and S1 oxide or a combination thereof is formed using a method such as a CVD method, a plasma CVD method, or an RF sputtering method, and this is used as the transfer pattern support layer 5. This transfer pattern support layer 5 is an X-ray transparent layer.

Next, as shown in FIG. 4, a resist film 6 is formed on the narrow surface of the cough transfer pattern support I-5 by, for example, a normal optical exposure method so as to correspond to the area of the opening ll54 formed previously. . In this case, the alignment between the window 4 and the resist 116 is determined by using the 81$ crystal substrate l on both the exposure mask used to form the cough opening 4 and the exposure mask used to form the resist film 6. <11 o
The setting is advantageously carried out by means of a nine mark so that it is possible to align the two facets indicating the direction.

Next, after covering the other surface of the 8i $ crystal substrate 1 with a resist film 7, the cough resist film 6 is used as a protective film and the mosquito transfer pattern (turn support layer 5) is removed by plasma etching or the like.
St is removed by etching to form 5', which is provided in the opening region 81 where the surface of the 81jlL crystal substrate l is exposed. Then, the resist that is no longer needed is peeled off to form the state shown in Figure 1g5.

Next, as shown in Figure @6, 1 ink transfer) (turn support layer 5I
A desired transfer pattern 9 is formed on the surface of the substrate by a selective Φ method, a lift-off method, or the like, using U or Pt having a thickness of several thousand Å to 1 mO. This transfer pattern 9 forms a layer that absorbs both X-rays and visible light.

In the above process, the opening area 8 of the transfer pattern support layer 51 is filled with a resist, and after the transfer pattern 9 is formed, the resist is removed to expose the clean SM crystal surface.

Next, set the above sample in a Si epitaxial device and S
Selective growth is performed under reduced pressure (~80 TORR) using an iH, C1l source, and the growth conditions are such that the substrate temperature is ~100 TORR.
0°C, H, carrier gas ~100 t/min%
SiH, Cl3 was fed at ~600 cc/min, and the growth rate was ~0.5 μm/min.
An 8i crystal is selectively grown to a thickness of 1 to 10 μm only in the opening 8 where the i crystal surface is exposed. Transfer pattern support layer 51
No Si crystals are deposited on the transfer pattern 9. This occurs because the raw material gas contains halogen, and the SM surface of the phosphor crystal extracted from j1 serves as a seed crystal, making p growth easier. Furthermore, growth under reduced pressure allows the growth surface to be smoothed, and its shape corresponds to the thickness of the selectively grown film as shown in FIG. It also grows.

Finally, hold the heavy metal pattern with an arbitrary jig using an O/G, etc., and place a predetermined area of the cram crystal substrate l through the opening 4 to form an anisotropic solution such as a KOH aqueous solution. The reinforcement support beams 11 and the transfer pattern area 11 formed of a part of the 5T4i crystal substrate l as shown in FIG. Complete.

In the structure shown in FIG. 8, the transfer pattern support layer 5
As a result of removing a predetermined area that is strained by the tensile stress of 1, the stress at the interface with the reinforcing support beam is significantly reduced, and furthermore, a spacer made of Rin crystal 81 is selected on the surface of the reinforcing support beam. Since the XStm optical mask is formed in a uniform manner, it is possible to obtain an XStm optical mask with extremely good flatness.

In the example shown in FIG. 8, as can be seen from the fact that only the central part is shown, the transfer pattern support layer is removed from almost all of the reinforcing support beams, so it is most reliable. The desired effect is achieved. However, the reinforcing support beam part corresponding to the window frame located in the center of the mask as shown in the figure is not forcibly removed, and by removing the part corresponding to the surrounding window frame, the size of the mask can be made sufficiently small. There are cases. Furthermore, although it is convenient to remove the entire periphery of the window frame in an annular manner, it may be sufficient to remove the entire periphery in some cases.

According to the first aspect of the present invention, the transfer pattern support layer in the region that makes a small contribution to lamination adhesion promotes the deformation of the reinforcing support beam and the sleeping mask, but by removing the transfer pattern support layer in this region, the mask Overall resistance can be significantly reduced. Furthermore, single crystal SN is deposited in the area where the transfer pattern support layer has been removed by one-selection epitaxial growth, and a spacer is used to maintain a uniform distance between the wafer and the transfer pattern support layer in the X* exposure process. Since it is used as a %XII exposure, the processing accuracy of the %XII exposure is significantly improved, and furthermore, the pattern of the X1m exposure mask and the pattern support layer can be prevented from being contaminated or damaged.

[Brief explanation of the drawing]

Figures 1 to 8 are XSS according to the first and second inventions.
FIG. 2 is a schematic cross-sectional view showing the manufacturing process of an example of a light mask, with the central portion thereof being extruded. l...St phosphorus crystal substrate, 2.2'...
sio, membrane, 3...811N41L 2"・
... Complement formed by a part of 2' *@s a'...
・・・Supplementary name formed from part of 3, 4・・・・・・21
1 and 31, WA' is opening part, 5...transfer pattern support layer, 6, 7...register X), 5
'...Transfer pattern support layer formed by part of 5, 8...9 opening area by removing part of 5, 9.
...Transfer (turn, 10...Spacer formed by epitaxial St) 14...l
Reinforcement support beam formed by a part of % 11...Transfer pattern area formed by removing a part of l. Half 1 Figure Half 2 Father φ Dormitory '3 Kuni 11

Claims (1)

[Claims] 1. In an X-ray exposure mask comprising an X-ray transparent thin film having tensile stress and a silicon crystal reinforcing support frame supporting the thin film, Iw present on the reinforcing support beam A XIII optical mask characterized in that a portion of the X-ray transparent thin film is removed to provide an opening region, and a spacer made of silicon is provided in the opening region. 2. A silicon nitride film or a silicon oxide film, or both, is deposited on the surface of either one of the silicon single crystal substrates, and desired areas of these films are removed by etching to form the silicon tower crystal substrate. A process of entangling the narrow side,
a step of depositing an X-ray transparent layer on the other surface of the silicon single crystal substrate; a step of forming and arranging a layer absorbing both X-rays and visible light in a desired pattern on the X-ray transparent layer; A step of selectively epitaxially growing silicon on the exposed silicon single crystal substrate 11 by removing a predetermined region of the X-ray transparent layer by etching and exposing a part of the surface of the silicon monocrystalline substrate 11; patterning into a desired shape and using one or both of a silicon nitride film and a silicon oxide film as a protective film, etching away a part of the silicon single crystal substrate to expose the X-ray transparent layer; A method for manufacturing an X-ray exposure mask, characterized by: