JPS63104327A - X-ray mask and manufacture thereof - Google Patents

Abstract

PURPOSE:To accurately form a transfer pattern in a hole corresponding part by forming the thickness of a transfer pattern absorption layer in the corresponding part thinner than that of an absorption of layer of a corresponding part out of the holes in combination of a 3-layer process and twice plating processes. CONSTITUTION:First gold plating is executed on a corresponding part 2 out of holes to form a first gold plating layer 16 in a thickness of approx. 0.5-1.5mum. Second gold plating is performed in a thickness of approx. 0.7-1.0mum, a second gold plating layer 19 is selectively formed on the layer 16 on the part 2, and a gold plating layer 20 is simultaneously selectively formed in a pattern on a hole corresponding part 1. Then, a gold-plated layer 20 selectively patterned in a thickness of approx. 0.7-1.0mum as an absorption layer, i.e., a transfer pattern 20a is formed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an X-ray mask and a method for manufacturing the same.
More specifically, the present invention relates to an X-ray stepper mask used to transfer a fine pattern to a resist surface on a wafer by X-ray exposure during the manufacture of LSIs, etc., and a method for manufacturing the same.

[Conventional technology]

As a conventional example of this type of X-ray mask and its manufacturing method, the manufacturing process disclosed in Japanese Patent Application Laid-Open No. 59-82855 is shown in FIGS. 3(a) to 3(g).

That is, in the conventional method shown in FIG.
2, an opening 31 including a transfer pattern 44 and a mask region 32 consisting of a gold absorption layer 43 are formed (see FIG.
)) Next, after applying a photoresist 45 to the other surface of this substrate 41 (FIG. 4(b)), this photoresist 45 is exposed and developed, leaving a resist pattern 45a that will become the frame outer ring. Then, the same substrate surface is used as an exposed portion 48 (FIG. 4(C)).

Thereafter, in a first etching step, using the resist pattern 45a as a mask, selective etching is performed until the thickness of the silicon plate in the exposed portion 46 becomes approximately IQgm to form a thin recess 47 (see FIG. d)), and after applying a photoresist 48 again to the surface of this thin recessed portion 47 (FIG. 4(e)), this photoresist 48 is exposed and developed to form a part other than the area corresponding to the opening 31. The four thin wall portions 47 corresponding to the portions corresponding to the openings 31 are formed into the exposed portions 49 by patterning means that uses a positioning method using infrared light irradiation from the back side, for example, while leaving the resist pattern 48a. (Figure (f)
).

Then, in a second etching step, using the resist pattern 48a as a mask, the silicon in the exposed portion 49 is selectively etched away, and the thin film 42 portion of the silicon nitride film corresponding to the opening 31 is exposed ( The same figure (g
)) In this way, the desired mask plate for an X-ray stepper is obtained.

[Problem that the invention seeks to solve]

However, in the X-ray stepper mask formed by the conventional method, back etching of silicon, which is said to have the lowest manufacturing yield, is carried out during the manufacturing process.
This back etching process has to be performed twice, and has disadvantages such as greatly increasing the number of manufacturing processes and making operations extremely complicated. Because this process is repeated, the positional distortion of the mask is large, and mask accuracy cannot be improved by aligning the apertures by irradiating infrared light from the back side. .

This invention was made to improve these conventional problems, and its purpose is to manufacture a high-precision mask with a relatively simple process, including the alignment of the apertures. I did it like that. This kind of X-ray mask,
The object of the present invention is to provide a novel method for manufacturing the same.

[Means for solving problems]

In order to achieve the above object, an X-ray mask and a method for manufacturing the same according to the present invention provide an X-ray mask in which an aperture corresponding portion corresponding to a transfer pattern and an aperture corresponding portion are respectively formed on a mask support substrate. , 3-layer process and 2
In combination with the plating process of It is designed so that it can be formed with precision.

[For production]

That is, in this invention, the first plating layer as an absorbing layer is formed only on the opening-corresponding portion, and at the same time, the alignment mark portion is formed on the non-opening corresponding portion, so that the second plating layer is formed only on the opening-corresponding portion. When forming layers,
In the former, the thickness of the transfer pattern absorbing layer in the aperture-corresponding portion can be formed thinner than the film thickness of the absorbing layer in the aperture-corresponding portion;
In the latter case, the transfer pattern absorbing layer in the opening corresponding portion can be formed with high precision using the alignment mark portion as a reference.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an X-ray mask and a method for manufacturing the same according to the present invention will be described in detail below with reference to FIGS. 1 and 2.

FIGS. 1(a) to 1g) are sectional views showing the method of this embodiment in the order of steps, and FIG. 2 is a plan view of an X-ray mask manufactured by the above method.

In this FIG. 1 embodiment method, silicon support ring 12. and 9 formed on one side of this support ring.
For example, a mask support substrate 11 made of a thin film 13 of silicon nitride is used (FIG. 4(a)). A plating base layer 14 of gold (Au) is first formed on one surface of the thin film 13 of the support substrate 11 by sputtering, and then a plating base layer 14 of gold (Au) is formed on the thin film 13 of the support substrate 11 by sputtering. Approximately 1.0 to 1.5 p of the bottom resist 15 of the three-layer process
, and spin-coded to a thickness of about m (FIG. 4(b)).

Next, using an electron beam exposure device or an optical stepper, the bottom resist 15 is exposed and developed to form the aperture corresponding portion 1 and the 7-line mask portion 3 in the aperture corresponding portion 2. At the same time, a first gold plating is performed on the outside of the opening corresponding part to form a first gold plating layer 16 with a thickness of about 0.5 to 1.5 gm (see FIG. C)).

Thereafter, an intermediate layer 17 of a three-layer process is formed on the first gold plating layer 16 to a thickness of about 0.1 to 0.5 grs, and a top resist of a three-layer process is formed thereon. For example, spin code the EB resist (
Figure (d)).

Next, a predetermined exposure pattern is transferred and developed using the alignment mark section 3 as a reference, and a resist pattern 18a is selectively formed in the area of the opening corresponding section 1 of the top resist 18. By patterning the intermediate layer 17 using the resist pattern 18a obtained as a mask, the intermediate layer pattern 17a is selectively formed. Furthermore, using the resist pattern 18a and the intermediate layer pattern 17a as a mask, a bottom resist is formed. 15 is selectively dry-etched to obtain a stencil 15a (FIG. 4(e)).

Next, on top of these, a second gold plating is applied to approx.
7-1. In the opening corresponding portion 2, the second gold plating layer 19 is selectively formed on the first gold plating layer 16 to a thickness of about Q pLm, and in the opening corresponding portion 1, the second gold plating layer 19 is selectively formed on the first gold plating layer 16. are selectively patterned at the same time (FIG. 6(f)). In other words, in this case, the two-layered gold plating layer 16.19 is selectively applied to the aperture corresponding portion 2 with a thickness of about 1.2 to 2.5 pm as an absorbing layer. On the other hand, a selectively patterned gold plating layer 20. is formed on the opening corresponding portion 1 and has a thickness of about 0.7 to 1.04 m as an absorption layer. In other words, the transfer pattern 20a is formed here.

Finally, the plating stencil 15a is selectively removed by oxygen plasma etching or the like, and the plating base layer 14 thereunder is selectively removed by Ar sputter etching or the like (FIG. 1(g)).
The desired X-ray mask is obtained.

FIG. 2 shows a plan view of the X-ray mask obtained in this manner. In this configuration, since the alignment mark portion 3 is formed in a thin film portion on the silicon support ring 12, it is transferred during X-ray exposure. has no effect on

Next, specific examples of each will be described.

Concrete example work.

Mask substrate made of 8N and polyimide (Microni
(manufactured by x company), a plating base layer of 300% Au/Ti
CMS-EX (manufactured by Toyo Soda Co., Ltd.) was deposited as a bottom resist on this plating base layer to a thickness of 1.
It was spin-coded to a film thickness of 2 μm and EeBES-40 (
(manufactured by Varian), the opening corresponding portion and the alignment mark portion were formed by exposure and development, and the first plating was performed to form an Au layer with a thickness of 1.0 grs on the opening corresponding portion.

After baking this at 150℃, this Au
A No film was sputtered to a thickness of 100 OA on layer 5 to form an intermediate layer, and on top of that, RE-500 was applied as an EB resist.
0P (manufactured by Hitachi Chemical Co., Ltd.) at 0.5. After spin neatening to a thickness of cm, a predetermined pattern is formed using EeBES-40 in the opening corresponding portion using the alignment mark portion as a reference, and at the same time, the resist in the area outside the opening corresponding portion is also exposed.

Next, the middle layer and Mo film are subjected to OF4+02RIE plasma etching, and subsequently the CMS-EX bottom layer is etched using 02R
After WE plasma etching and wet removal of the intermediate layer and Mo1Q, a second gold plating was applied to a thickness of 0.7 gm, and a 0.71 Lm absorbing layer was applied to the corresponding opening area.
It was possible to obtain a transfer pattern of 1.7 JLm of Au layer and 1.7 JLm of Au layer as an absorption layer in the aperture corresponding part, and then remove the metal stencil and the plating base to achieve the desired high precision. completed an X-ray mask.

Specific example ■.

After forming a plating base layer on the mask substrate in the previous example, 0FP is applied as a bottom resist on this plating base layer.
Apply R-800 to a film thickness of 1.5 pm, and use a proximity aligner to form the opening corresponding area and the 7 alignment mask area by exposing and developing using a predetermined mask prepared in advance. Due to plating, 1.
．． An Au layer with a thickness of 0.0 cm was formed.

From then on, the manufacturing process is carried out in the same manner as in the previous example, and a 0.000. A transfer pattern of a full Au layer was formed, and an Au layer of 1.74 rs was formed as an absorbing layer in the aperture corresponding portion, thereby completing the desired high-precision X-ray mask.

Using the X-ray mask obtained as described above, the transferred pattern was applied to a resist on the surface of the sea urchin, etc., using PdLa.
exposed by a line. In this case, in an electron beam excitation type X-ray exposure apparatus with an accelerating voltage of 25 KV.

The gold (Au) film thickness of the absorption layer that forms the transfer pattern is 0.
．． When the film thickness is 7g rtr, the mask contrast is 7, and when the same film thickness is 1.7JLI6, it is 2.
It was o. (With 7' + Tsuteko\, it was confirmed that exposure by step-and-repeat X-ray exposure transfer could be performed without causing unnecessary X-ray fog around the resist pattern.

Incidentally, in the method of the above embodiment, after forming the first gold plating layer, the intermediate layer is formed immediately after, but once the resist in the area corresponding to the opening is removed and then again. After spin-coding the bottom resist, the middle layer,
Then, a top resist may be formed to perform a three-layer process.

〔Effect of the invention〕

As described in detail above, according to the present invention, the opening corresponding to the transfer pattern is formed on the mask support substrate.

and an X-ray mask in which aperture corresponding portions are formed respectively, a three-layer process and two plating processes are combined to form the first plating layer as an absorbing layer only on the aperture corresponding portions, and At the same time, by forming an alignment mark part in the corresponding part outside the opening, when forming the second plating layer, in the former method, the film thickness of the transfer pattern absorbing layer in the part corresponding to the opening can be adjusted to the thickness of the transfer pattern absorbing layer in the part corresponding to the opening. It can be formed thinner than the absorption layer, thereby eliminating positional distortion of the mask pattern and eliminating unnecessary X-ray fog around the pattern. In the latter method, the alignment mark part is used as a reference. As a result, the transfer pattern absorbing layer in the opening-corresponding portion can be formed with high precision, and the manufacturing yield can be significantly improved.

[Brief explanation of the drawing]

Figures 1 (a) to g) are cross-sectional views showing the manufacturing method according to an embodiment of the present invention in the order of steps, and Figure 2 is a plan view of the X-ray mask obtained by the same manufacturing method. 3(a) to 3(g) are sectional views showing the conventional manufacturing method of the above in order of steps. 1...Aperture compatible part, 2...Aperture compatible part, 3...
...Alignment mark section. 11... Mask support substrate, 12... Silicon support ring, 13... Thin film of silicon nitride film, 14...
...Plating base layer, 15..Bottom resist,
1B...first gold plating layer (absorption layer), 17...
・Intermediate layer, 17a...Intermediate layer pattern, 18...
-Top resist, 18a...Top resist pattern, 19.20...Second gold plating layer (absorption layer), 20a...Transfer pattern (absorption layer). Agent Masuo OiwaFigure 1 19, 20 ;42qL)kl TSW)f (1;L
Small snow) 20a; Hoshibaban 7-n (suze collection) Figure 2

Claims (2)

[Claims] (1) In an X-ray mask in which an aperture corresponding portion corresponding to the transferred pattern and a corresponding portion outside the aperture are respectively formed on a mask support substrate, the film thickness of the absorption layer of the transferred pattern within the aperture corresponding portion is An X-ray mask characterized by being formed thinner than the thickness of the absorbing layer at the external facing part. (2) Using a support ring and a mask support substrate made of a thin film formed on the support ring, first, a plating base layer is formed on the thin film, and then a bottom resist is applied, and the bottom resist is exposed. , developing to selectively form an alignment mark portion on the opening corresponding portion and the outside corresponding portion of the transfer pattern, and forming a first plating layer on the outside corresponding portion; A process of forming an intermediate layer on the plating layer and applying a top resist, and transferring and developing the top resist based on the alignment mark part to form a resist pattern in the opening corresponding part, and masking this. the intermediate layer and then the bottom resist by selective etching, and the step of simultaneously selectively forming a second plating layer thereon; The absorption layer as a transfer pattern by plating layer 2 is applied to the opening corresponding part,
A method for manufacturing an X-ray mask, characterized in that an absorption layer formed by a second plating layer is formed on each of the absorption layers.