JPH02268414A - X-ray mask - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] Regarding an X-ray mask, the present invention provides an X-ray mask that can make it difficult for a stencil pattern to be deformed by X-ray irradiation and that can perform highly accurate mask positioning. An X-ray mask having a structure including a stencil pattern on an X-ray transparent film and an X-ray absorber on the X-ray transparent film on which the stencil pattern is not formed, the stencil pattern being is composed of diamond-like carbon, or has a stencil pattern on the X-ray transparent film, and an X-ray absorber on the X-ray transparent film on which the stencil pattern is not formed. Therefore, the stencil pattern is made of BezC.

[Industrial application field]

INDUSTRIAL APPLICABILITY The present invention relates to an X-ray mask and can be applied to microfabrication technology for manufacturing semiconductor integrated circuits, and more specifically, can make it difficult for a stencil pattern to undergo deterioration or deformation due to X-ray irradiation. Regarding X-ray masks.

In recent years, with the increase in the degree of integration of integrated circuits, the minimum size has decreased to 0.50.
~0.20 μm, so-called sub-micron, sub-half
There is a need for buttering technology that butters in microns. In order to respond to such miniaturization of patterning technology, it is especially effective to use X-rays with a short exposure wavelength and low diffraction amount, and the technology development of X-ray masks that expose using X-rays is strongly progressing. It is being The X-ray mask here has a stencil pattern in which integrated circuit patterns, etc. are formed on an X-ray transparent film that transmits X-rays, and absorbs X-rays on the X-ray transparent film on which no stencil pattern is formed. This is an XvA mask with a structure that has an X-ray absorber.

X-ray masks have the advantage of forming fine patterns and are useful for achieving high integration, but the stencil pattern is particularly susceptible to deterioration and deformation due to X-ray irradiation, which makes it difficult to accurately position the mask. There was a problem that alignment could not be performed.

There is a need for an X-ray mask that can prevent the stencil pattern from being altered or deformed by X-ray irradiation due to shifting force, and can perform highly accurate mask positioning.

[Conventional technology]

The prior art will be specifically explained below.

In order to improve the transmittance of the exposed X-rays, a thin film (also called a membrane) made of a material with a small atomic number is selected and used for the X-ray transmission film that makes up the X-ray mask. Materials mainly consisting of metals with large atomic numbers are selected and used for the absorber in order to reduce the transmittance of X-rays.

As a result, the material for the X-ray transparent film is, for example, single crystal Si.
, polycrystalline St, polycrystalline SiC, amorphous BN, 5t
Nx, etc. are selected and used, and as the material of the X-ray absorber, for example, brating Au, sputter W1 sputter Ta, etc., or nitrides of the above metals are selected and used.

Note that the X-ray mask is configured such that a stencil pattern is formed on an X-ray transparent film, and an X-ray absorber is formed on the X-ray transparent film on which the stencil pattern is not formed.

Further, as a material for the stencil pattern, an organic material such as polyimide is used.

[Problem to be solved by the invention]

However, in such conventional X-ray masks, the stencil patterns made of organic materials such as polyimide are easily altered and deformed by X-ray irradiation, making it impossible to perform highly accurate mask positioning. There was a problem with this.

It may be possible to form only the X-ray absorber on the X-ray transparent film without forming a stencil pattern, but if the stencil pattern is not left, the fine X-ray absorber with a high aspect ratio will be deformed. Or it could fall. Therefore, an X-ray mask must be formed with the stencil pattern remaining.

Therefore, the present invention can make it difficult for the stencil pattern to deteriorate or deform due to X-ray irradiation, and can stably provide an absorber with a high aspect ratio without pattern defects.
The present invention also aims to provide an X-ray mask that can perform highly accurate mask positioning.

[Means to solve the problem]

In order to achieve the above object, the X-ray mask according to the first invention
An X-ray mask having a structure in which a stencil pattern is formed on a radiation-transmitting film, and an X-ray absorber is formed on the X-ray-transmitting film on which the stencil pattern is not formed, the stencil pattern being made of diamond-like carbon. It is something to do.

In order to achieve the above object, the X-ray mask according to the second invention
An X-ray mask having a structure in which a stencil pattern is formed on a radiation-transparent film, and an X-ray absorber is formed on the X-ray transmission film on which the stencil pattern is not formed. It is composed of high Be2C.

[Function] In the first invention, the stencil pattern formed on the X-ray transparent film is made of diamond-like carbon.

In the second invention, the stencil pattern formed on the X-ray transparent film is made of BezC.

Therefore, according to the first and second inventions, it becomes possible to make it difficult for the stencil pattern to undergo deterioration or deformation due to X-ray irradiation, and it becomes possible to perform highly accurate mask positioning. .

Here, the stencil pattern is less susceptible to alteration and deformation due to X-ray irradiation (this is possible because diamond-like carbon, Be2C, is chemically more stable than conventional organic materials such as polyimide). It is estimated that this can be achieved by

〔Example〕

Hereinafter, the present invention will be explained based on the drawings.

1 and 2 are diagrams explaining an embodiment of an X-ray mask according to the first invention, FIG. 1 is a diagram showing the configuration of an embodiment of the first invention, and FIG. a) to (g) are diagrams illustrating a manufacturing method of an embodiment of the first invention.

In these figures, 1 is a substrate made of, for example, St; 2 is a substrate made of, for example, St;
3 is an ion implantation layer, 4 is a diamond-like carbon film, 5 is a reinforcing ring, 6 is a glass-on-glass film, 7 is a resist film, and 8 is an integrated circuit. A pattern 9 is a stencil pattern made of diamond-like carbon, which is formed by selectively etching the diamond-like carbon film 4. 1o is, for example, a fully plated X-ray absorber.

Next, the manufacturing method will be explained.

First, as shown in Fig. 2(a), the plate thickness is, for example, 500 mm.
A group vi1 of ~1000 μm is placed in a vapor phase growth furnace and heated at a temperature of, for example, approximately 1100”C, and propane and dichlorosilane gases are introduced as growth gases to grow polycrystalline SIC on the substrate 1 to increase the film thickness. The X-ray transmitting film 2 is formed to have a conductivity of, for example, about 2 to 3 μm and a conductivity of, for example, about 10 Ω·cm.

Next, as shown in FIG. 2(b), an ion implantation method in which the impurity is, for example, boron (or phosphorus may be used) and the dose is, for example, about I
Line transmission II! By introducing impurities into the X-ray transmitting film 2, the depth from the surface of the X-ray transparent film 2 is, for example, 1,000 people, and the sheet resistance is, for example, °1~1.
An ion implantation layer 3 of 50Ω·CI is formed.

Next, as shown in FIG.
is put into the vapor phase growth furnace again and heated at a temperature of, for example, about 1000°C, and ions are grown by introducing, for example, methane gas and hydrogen gas (the flow rate ratio of methane gas is about 1%) as growth gases.
The film thickness on the implantation layer 3 is, for example, 1 to 1.5
A diamond-like carbon film 4 having a conductivity of, for example, IMΩ·cm in μm is formed.

Next, as shown in FIG. 2(d), a reinforcing ring 5 is attached directly to the substrate 1 using an adhesive.

Next, as shown in FIG. 2(e), the substrate 1 is selectively etched from the back surface of the substrate 1 along the inner diameter of the reinforcing ring 5 by wet etching using, for example, a mixed solution of hydrofluoric acid and nitric acid, and then etched with X-rays. The permeable membrane 2 is exposed.

Next, as shown in FIG. 2(f), a spin-on glass film 6 is formed on the diamond-like carbon film 4, and a spin-on glass film 6 is formed on the diamond-like carbon film 4.
After a resist is applied onto the on-glass film 6, the resist is exposed to electron beam, developed, and patterned to form a resist film 7 serving as a mask. At this time, a predetermined integrated circuit pattern 8 is formed on the resist film 7. Then,
Spin-on glass film 6 using resist film 7 as a mask
is selectively etched to expose the diamond-like carbon film 4. The spin-on glass film 6 here is necessary for forming a stencil pattern on the diamond-like carbon film 4, but the resist @ 7 is made of two-layered photosensitive PMSS or photosensitive PVSS. If the spin-on glass film 6 is used, the spin-on glass film 6 may not be formed.

Next, as shown in FIG. 2(g), the integrated circuit pattern 8
Using the resist film 7 and spin-on glass film 6 as masks, the diamond-like carbon WA 4 is selectively etched by, for example, RIE using oxygen gas to form a stencil pattern 9, and the ion implantation layer 3 is etched. expose. At this time, an integrated circuit pattern 8 is formed on the stencil pattern 9. Here, since the etching rate of the Xks transmission film 2 made of polycrystalline SiC by oxygen gas is extremely low, the ion implantation layer 3 formed in the X-ray transmission film 2 is not removed.

Then, complete plating liquid (product name: Neutronex 309 (
Made by Sino-Japanese precious metals ■)t! The X-ray absorber IO made of all plating (brating Au) is formed on the exposed ion implantation layer 3 by the X-rays having the structure shown in FIG. The line mask is completed. The stencil pattern 9 here functions as a mask, and the ion implantation layer 3 functions as a conductive layer necessary for forming the entire plating.

That is, in the above embodiment, since the stencil pattern 9 is made of diamond-like carbon, the stencil pattern is less likely to be altered or deformed due to X-ray irradiation, and highly accurate mask positioning can be performed. can.

It goes without saying that diamond-like carbon is chemically more stable than conventional organic materials such as polyimide, and that diamond-like carbon is less susceptible to alteration and deformation of the stencil pattern due to X-ray irradiation. It is estimated that this can be achieved by having a dense molecular structure among other X-ray transparent materials.

3 and 4 are diagrams for explaining an embodiment of an X-ray mask according to the second invention, FIG. 3 is a diagram showing the configuration of an embodiment of the second invention, and FIG. It is a figure explaining the manufacturing method of one Example of the 2nd invention.

In addition, FIG. 1 and FIG. 2 (i), N) are X shown in FIG.
FIG.

In these figures, Figures 1 and 2 (a) to (g)
The same reference numerals indicate the same or corresponding parts, and 21 is Bez
C films, 22a and 22b are Sin films, and 23 is a stencil pattern made of Be2C.

Next, the manufacturing method will be explained.

First, as shown in FIG. 4(a), the plate thickness is, for example, 500 mm.
Substrate 1 with a thickness of ~1000 μm was placed in a vapor phase growth furnace for approximately 110 μm.
Polycrystalline S is formed on the substrate 1 by heating at a temperature of 0'C and introducing propane and dichlorosilane gases as growth gases.
iC is grown to form an X-ray transparent film 2 having a film thickness of, for example, about 2 to 3 μm and a conductivity of, for example, about 10 Ω·am.

Next, as shown in FIG. 4(b), the impurity is, for example, boron (or phosphorus may be used), and the dose is, for example, 1×101th.
An impurity is introduced into the X-ray transparent membrane 2 by an ion implantation method of approximately 1/C to a depth of about 1,000 people from the surface of the X-ray transparent membrane 2, and the sheet resistance is, for example, about 1~1.
An ion implantation layer 3 of 5Ω·1 is formed.

Next, as shown in FIG. 4(C), the substrate l on which the X-ray transparent film 2 and the ion implantation layer 3 have been formed is again placed in a vapor phase growth furnace at a temperature of about 100°, for example. For example, methane gas (any hydrocarbon is fine) and B e t (
Introduce z gas (methane gas flow rate ratio is about 1 to 5%) and make the film thickness about 1 to 5 μm, for example! Total 3e2C membrane 2
Form 1. Instead of BeHt gas, a gas such as BeClt gas or BeBrz may be used, or a mixture of the above gases and a hydrocarbon such as methane gas may be used as the growth gas. Reactions excited by RF plasma or microwave plasma may also be used.

Next, as shown in FIG. 4(d), a SiOz film 22a of, for example, 100 to 200 layers is formed on the BetC film 21 by, for example, the CVD method.

Next, as shown in FIG. 4(e), the reinforcing ring 5 is attached to the surface of the substrate 11 using an adhesive.

Next, as shown in FIG. 4(f), the substrate 1 is selectively etched from the back surface of the substrate 1 along the inner diameter of the reinforcing ring 5 by wet etching using a mixed solution of hydrofluoric acid and nitric acid, for example, to pass through the XvA. Membrane 2 is exposed.

Next, as shown in FIG. 4(g), s i O! Membrane 22
A resist is applied onto the surface a, and this resist is patterned by, for example, electron beam exposure and development to form a resist film 7 serving as a mask. At this time, a predetermined integrated circuit pattern 8 is formed on the resist 11!7.

Next, as shown in FIG. 4(h), for example, B Cl 3 gas (CCZ) is applied using the resist film 7 as a mask.

gas, BBrs gas may be used)
The i 2 O film 22a and the Be2C film 21 are selectively etched to form a stencil pattern 23 and expose the ion implant WA3. In this case, the X-ray transparent film 2 made of polycrystalline SiC is BCI1
Since the etching rate with the three gases is extremely low, the ion implantation layer 3 formed within the X-ray transparent membrane 2 is not removed. Note that ECR etching with a DC bias applied to the substrate may be performed instead of RIH.

Next, as shown in FIG. 4(i), Stow is deposited on the entire surface by, for example, the CVD method, so that the film thickness is, for example, 5.
An IOt film 22b is formed. At this time, S is applied to the exposed sidewall portion of the stencil pattern 23 and the exposed portion of the ion implantation layer 3 shown in FIG. 4(h).
The iOz film 22b is formed, and the film thickness of the Sing film 22a becomes thicker because Sin is further deposited on the film 22a.

Next, as shown in FIG. 4(J), 5iOz films 22a and 22b are formed on the stencil pattern 23 and on the sidewalls of the stencil pattern 23 by anisotropically etching the SiO□ by, for example, the RIH method using F-based gas. The ion implantation layer 3 is left exposed.

The X-ray absorber 10 is then placed in a fully plated (trade name: Neutronex 309 (manufactured by Nichi-no-Kizoku) tank) and subjected to brating to form the fully plated X-ray absorber 10, as shown in Figure 3. The X-ray mask of the structure is completed, with the ion implantation layer 3 serving as the conductive layer necessary to form the full plating.

That is, in the above embodiment, since the stencil pattern 23 is made of Be2C, the stencil pattern is less likely to be altered or deformed due to X-ray irradiation, and highly accurate mask positioning can be performed.

Here, it is assumed that the ability to make the stencil pattern less susceptible to deterioration and deformation due to X-ray irradiation is achieved because Be2C has a denser molecular structure than conventional organic materials such as polyimide. be done.

In the above embodiment, the case where SiO□ was formed as a protective film on the stencil pattern 23 was explained, but A2□0. , St, N, etc. may be formed.

〔Effect of the invention〕

According to the first and second aspects of the invention, it is possible to make it difficult for the stencil pattern to deteriorate or deform due to X-ray irradiation, and it is possible to perform highly accurate mask positioning.

[Brief explanation of drawings]

1 and 2 are diagrams for explaining an embodiment of the X-ray mask according to the first invention, FIG. 1 is a diagram showing the configuration of an embodiment of the first invention, and FIG. FIGS. 3 and 4 are diagrams explaining an embodiment of the X-ray mask according to the second invention; FIG. FIG. 4 is a diagram illustrating a manufacturing method of an embodiment of the second invention. 2...X-ray transparent membrane, 4...diamond-like carbon membrane, 9.23...
...Stencil pattern, IO...X-ray absorber, 21...Be. C membrane. Diagrams illustrating the manufacturing method of an embodiment of the first invention

Claims (2)

[Claims] (1) An X-ray mask having a structure in which a stencil pattern is formed on an X-ray transparent film, and an X-ray absorber is formed on the X-ray transparent film on which the stencil pattern is not formed, and the stencil pattern is formed using a diamond. An X-ray mask characterized by being composed of shaped carbon. (2) An X-ray mask having a structure including a stencil pattern on an X-ray transparent film and an X-ray absorber on the X-ray transparent film on which the stencil pattern is not formed, the stencil pattern being Be_2C. An X-ray mask characterized by comprising: