JPH02181906A - X-ray transmitting film holding frame, x-ray mask blank and x-ray mask structure - Google Patents

Abstract

PURPOSE:To prevent dust particles from being produced when fine powders are dropped or stripped off by a method wherein a holding frame is formed of a ceramic sintered substance whose surface has been treated so as to prevent the dust particles from being produced. CONSTITUTION:A holding frame used to hold an X-ray transmitting film is formed of a ceramic sintered substance whose surface has been treated so as to prevent dust particles from being produced. The surface of a ceramic sintered substance 3 which has been cut or polished is coated with and/or impregnated with an organic or inorganic binder 5. When the binder whose viscosity is comparatively low is used or it is used in comparatively large quantities, one part of gaps 7 at the inside of the ceramic sintered substance is impregnated with the binder. When the binder whose viscosity is comparatively high is used or it is coated in comparatively small quantities, the inside is not impregnated; the binder remains on the surface and forms a film 5. For example, alumina or the like can be enumerated as a ceramic which is used as a holding frame or a reinforcement body for a mask blank or an X-ray mask structure. An organic solvent solution of a moisture dispersed substance of an organic resin such as a polyimide resin or the like can be used as the organic binder; colloidal silica or the like can be used as the inorganic binder.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an X-ray transmitting film holding frame, an X-ray mask blank, and an X-ray mask used in semiconductor manufacturing equipment, particularly an exposure apparatus for performing X-ray exposure. Concerning structures.

(Conventional technology vR) In recent years, with the increase in density and speed of semiconductor integrated H1 circuits,
The trend is for the pattern line width of integrated circuits to be reduced by 70% in about three years.

With the further integration of large-capacity memory elements (for example, 4 MORAM), devices with a capacity of 18 Mbit and the like have come to be designed using the 0.5 μm rule. For this reason, printing devices are required to have even higher performance, and high performance such that the minimum line width that can be transferred is 0.5 μm or less is beginning to be required. Therefore, steppers using light in the XIa region (7 to 14) as the exposure light source wavelength are being developed.

The mask structures used in these X-ray exposure devices are
As shown in figure a, X-ray transparent +1Q made of X-ray transparent material
2 and a holding frame 3 that holds it under tension, and the X-ray transmission II! The X-ray absorbers 1 are formed on the X-ray absorber 22, which are arranged in a desired geometrical arrangement such as alignment marks.

The method of forming the xlI5A permeable film 2 is roughly classified depending on whether the material used is an organic thin film or an inorganic thin film. For the former, a material is selected that has high transmittance for X-rays and is transparent to visible light. Films such as polyimide, polyamide, and mylar are preferred due to their Young's modulus, coefficient of thermal expansion, and surface roughness. It is used in These X-ray transparent membranes 2 are attached to the holding frame 3 with an adhesive 4.
These X-ray transparent membranes 2 are held in tension by the X-ray transmissive membranes 2 and fixed in a form with sufficient flatness.

On the other hand, when using an inorganic material as the x1a permeable membrane 2,
As shown in FIG. 2, a film 2 of about 2 μm of silicon compound, particularly silicon nitride or silicon carbide, is formed on a silicon wafer 6 by chemical vapor deposition or the like so as to have a slight tensile stress. Next, when the silicon wafer 6 on which the film 2 has been deposited is removed by etching from the back side of 5 only the necessary area (the area for transmitting X-rays), a mask blank is created in which the inorganic thin film 2 is held under tension on the silicon wafer 6. is obtained. However, since the substrate 6 is thin in this state,
Since the strength is low and it is inconvenient in handling and practical use, it is common to use an original reinforcing body (holding frame) 3 bonded with an adhesive 4.

In either case, the holding frame or reinforcing body is
It is desirable to have sufficient strength, thermal stability, and light weight. Conventionally, quartz glass, borosilicate glass (Pyrex)
, stainless steel, etc. have been used, but recently ceramic sintered bodies have come to be used because they satisfy the above conditions well.

In particular, sintered bodies made of aluminum nitride and boron nitride (^I
N-BN) or a sintered body made of silicon nitride and boron nitride (S
Ceramics such as t3N4-BN) are preferably used because they are easy to cut.

(Problem to be Solved by the Invention) However, the above ceramic materials are made of aluminum nitride, silicon nitride, nitride 11!, which are raw materials before sintering. The fine powder remains in a fine state even after sintering, and even after cutting or polishing, the fine powder falls off or peels off, which is the most preferred source of dust in the semiconductor process, and its characteristics This is a situation where the company's superiority is not necessarily being taken advantage of.

Therefore, an object of the present invention is to solve the problems of the prior art described above,
Excellent X-ray transparent membrane holding frame and X-ray mask that do not cause dust generation problems even when using ceramic sintered bodies such as aluminum nitride, boron nitride, silicon nitride, silicon carbide, etc. as the holding frame or reinforcing body. An object of the present invention is to provide a blank and an X-ray mask structure.

(Means for solving problems) The above objectives are achieved by the present invention as described below.

That is, the present invention provides a holding frame for holding an X-ray transparent membrane,
An X-ray mask blank consisting of a holding frame holding a radiation-transmitting film, or an X-ray mask blank consisting of a desired pattern of X-ray absorber and an
X-ray mask structure, X-ray mask blanks, and X-ray mask structure, characterized in that the holding frame is made of a ceramic sintered body whose surface is treated to prevent dust generation. It is the body.

(Function) According to the present invention, the X-ray transparent 11Q holding frame, X-ray mask blanks, and
1il mask structure can be provided.

(Preferred Embodiments) Next, the present invention will be described in more detail by citing preferred embodiments.

Xi of the present invention! The X-ray transparent film 2 used in the formation of the il mask structure is made of beryllium (Ilc), titanium (
Inorganic substances such as Ti), silicon (Si), boron (B), etc. or their compounds, organic substances such as polyimide, polyamide, polyester, parylene, or a combination thereof, used as conventional X-ray transmission models. Any of these can be used in the present invention, and in order to maximize the amount of X-ray transmission, in the case of an inorganic film, 0.5 to 5 μm, and an organic film of 0.5 to 5 μm. In this case, the thickness is preferably 1 to 20 μm.

The method of forming these XM permeable films may be any conventionally known method. For example, when the XIId permeable A film 2 is made of an organic material such as polyimide, the organic film may be formed by, for example,
It is formed by tensioning and fixing it to a suitable holding frame 3 such as metal, ceramics, or glass using an adhesive 4 (see Fig. 1).Also, when the XLi1 transmission 11q2 is an inorganic material, the strength of the membrane 2 For example, the X-ray transparent film 2 is formed on the silicon wafer (holding frame) 6, and then an etching protection layer (not shown) (polyimide, silicon nitride film, etc.) is provided on the back surface, and 30% caustic potassium is used. By etching with an aqueous solution, an inorganic membrane 2 supported on the sea urchin 8 can be formed. In this case, since the strength of the silicon wafer 6 is insufficient, it is common to add a reinforcing body 3 made of metal, ceramics, glass, etc. (see FIG. 2).

The X-ray absorber formed on the X-ray transmitting rIQZ is generally made of a thin layer of a material with high density, such as gold, platinum, tungsten, tantalum, copper, nickel, or a compound containing them (for example, 0. 5 to 1 μm), which is used in conventional X-ray mask structures.
&s absorbers can be used in the present invention and are not particularly limited.

Such an X-ray absorber 1 can be produced, for example, by depositing a plating electrode layer on the X-ray transmission layer 2, patterning a single layer or multilayer resist on it by electron beam writing, and plating, for example, gold. A gold pattern, which is an X-ray absorber, is formed. Furthermore, an X-ray absorber can be formed by forming a film of W, Ta, etc. on an X-ray transparent film, forming a single layer or multilayer resist by electron beam writing, and then plasma etching the W or Ta layer. I can do it. Alternatively, the X-ray absorber may be formed in the back etching ft1T of the silicon wafer.

For adhesion between the X-ray transparent membrane and the holding frame or between the silicon wafer and the reinforcing body, an adhesive that shrinks little when cured, such as
It is preferable to use thermosetting adhesives such as epoxy, rubber, acrylic, and polyimide adhesives, photocuring adhesives, and solvent adhesives.

In the configuration of the X-ray mask structure as described above, the present invention involves forming the holding frame (including the reinforcing body) from ceramics by molding and sintering, and after cutting or polishing the molded body to 9E dust. It is characterized by preventive treatment.

The ceramic used as the holding frame, mask blank, or holding frame or reinforcing body of the X-ray mask structure of the present invention is 1, for example, alumina (^12 (+3)).

Zirconia (ZrO2), =r-durite (2M
g0・2^I2O3・5SiO□), Sialon (Si
・＾1・0・N), silicon carbide (SiC), aluminum nitride (AlN), silicon nitride (si3N4), other 5iC-7, rl)2, ＾120. -TiC and the like. In addition, as ceramic sintered bodies that can be cut, AlN-〇N-based, Si, N4-ON-based, and silicon carbide-based (
S iC), etc.

Among the above ceramics, ceramics having a Young's modulus of 100 GPa or more are particularly preferred for the present invention. More preferably, in order to prevent distortion due to heat generated by X-ray irradiation, ceramics having a linear expansion coefficient of txto-' of 11 or less is used.

In the present invention, the Young's modulus and linear expansion coefficient values of preferable ceramic materials are illustrated below.

GPa
ni-1 alumina (^bos) 3
70 7. Q
SiC) 400 Aluminum nitride (AIN) 280 Silicon nitride (
SiJJ 170-300SiC-ZrB2
360^120+-TiC390~ 41〇81205-TiO,220^IN-BN160 SiJ4-ON 130,~16G
5.8 to 8.8 X 10-' The present invention is not limited to the above-mentioned ceramics, and any ceramics having similar physical properties can be used in the present invention.

The above ceramics can be molded into a predetermined shape and sintered according to a conventional method to obtain a desired shape. ' Then, the desired size and grain size can be obtained by cutting or the like.

The shape of the holding frame and reinforcing body used in the present invention may be the same as a conventionally known shape, such as a ring shape, and the surface or inside of the mask holding frame or reinforcing body may be It is also possible to fix a magnetic material to.

Dust prevention treatment after cutting or polishing will be explained.

A preferred method for dust prevention treatment is a method by applying and/or impregnating an organic or inorganic binder 5. For example, as schematically shown in the first VAb or C, a ceramic sintered body 3 that has been cut or polished is This is a method of coating and/or impregnating an organic binder or an inorganic binder on the surface of the ceramic sintered body.If the binder has a relatively low viscosity or is used in a relatively large amount, the voids 7 inside the ceramic sintered body are The binder 5 is partially impregnated.On the other hand, if the binder has a relatively high viscosity or the amount applied is relatively small, the binder does not impregnate the inside and remains on the surface to form a coating [5. Although it is preferable to form a continuous film on the surface of the surface (Fig. 1, c), this is not essential. It may be the coating 5.

Examples of the organic binder that can be used include organic solvent solutions and water dispersions of organic resins such as polyimide resins, acrylic resins, epoxy resins, polyester resins, urea resins, melamine resins, and alkyd resins, and inorganic binders. As the material, colloidal silica or the like can be used.

The amount of binder applied and/or impregnated should be at least as high as in Figure 4d.
It is only necessary that a state of 0.
The object of the present invention can be fully achieved at a ratio of 1 to 50 g/m''.

Further, as another preferable dust generation prevention treatment of the present invention, Ti
N, Sit: % Si, N, , A1.03, coating with ceramic such as TiC, or metal plating such as nickel Kanigen plating is suitable for dust prevention treatment. With stiff ceramic coatings and metal plating, low temperature coating is possible and there are no pinholes.
It is hard and has excellent abrasion resistance, and a sufficient effect can be achieved with a thin J7 thickness of about 0.1 to 5 μm, for example.

(Example) Next, the present invention will be explained in more detail with reference to Examples.

Example 1 FIG. 1 is a diagram schematically showing a cross section (a) of an X-ray mask structure of this example and enlarged views (b to d) of its holding frame 3.

In the figure, an X-ray absorber 1 is formed on one side of an X-ray transparent film 2 in a desired pattern. Absorber 1 is approximately 0.7m
consisting of m gold. The X-ray transparent membrane 2 is made of a polyimide thin film with a thickness of 12 μm and a thin nickel film with a thickness of 0.03 μm.
It is a layered film. The peripheral portion of the X-ray transmission 1 and 2 is held on the upper end surface of an annular holding frame 3, and is bonded with adhesive 4 only on the inclined surface of the holding frame to maintain flatness. The holding frame 3 is made of machinable ceramics (for example, 81N-0N), and a dust prevention treatment layer 5 is formed on its surface by impregnating it with epoxy resin at a rate of about 5 g/rn' (solid content). ing. Furthermore, the holding frame 3 has an inner diameter of 50 mm and an outer diameter of 100 mm.
, is annular with a thickness of 6 mm.

Example 2 The x&! of the present invention was treated to prevent dust generation in the same manner as in Example 1 except that a polyimide resin was used in place of the epoxy resin in Example 1. The iI mask structure was IJ.

Example 3 A 1:P X-ray mask structure of the present invention was treated to prevent dust generation in the same manner as in Example 1 except that polyester resin was used instead of the epoxy resin in Example 1.

Embodiment 4 FIG. 2 is a diagram schematically showing a cross section of an X, V11 mask structure according to another embodiment of the present invention.

Back-etched silicone wafer (holding frame) 6
X-ray transmission +1 made of Si3N4 with a thickness of 2 μm on top
! 22 is formed, and xl&! made of W with a thickness of 0.8 μm is formed thereon. An IT absorber pattern 1 is formed. A reinforcing body 3 was adhesively fixed to this structure using an epoxy adhesive (manufactured by Alpha Giken Co., Ltd., model number 3500) 4.

The reinforcing body 3 in L is made of machinable ceramics (for example, AI
After evaporating chromium as a base material to a thickness of 061 μm on the surface of this reinforcing body, TiN 5 was coated to a thickness of 3 μm using an ion blasting method.

When comparing the X-ray mask structure of the present invention described in Section L with the same mask structure except that no dust generation prevention treatment was performed, it was found that the one according to the present invention had significantly reduced dust generation.

(Effects of the Invention) As explained above, the X-ray transparent membrane holding frame, the X-ray mask blank, and the The advantage is that an X-ray mask structure is provided.

[Brief explanation of the drawing]

FIGS. 1 and 2 are diagrams schematically showing a cross section of the X-ray mask structure of the present invention. 1: X-ray absorber 2: X-ray transparent membrane 3, holding frame (reinforcing body) 4: Adhesive 5/dust prevention +1-processing layer 6: Silicon wafer 7, void Figure 1

Claims (6)

[Claims] (1) A holding frame for holding an X-ray transparent membrane, characterized in that the holding frame is made of a ceramic sintered body whose surface is treated to prevent dust generation. (2) An X-ray mask blank consisting of a holding frame holding an X-ray transparent membrane, characterized in that the holding frame is made of a ceramic sintered body whose surface is treated to prevent dust generation. Line mask blanks. (3) In an X-ray mask structure consisting of an X-ray absorber with a desired pattern, an X-ray transmissive film that holds the absorber, and a holding frame that holds these, the holding frame has its surface treated to prevent dust generation. An X-ray mask structure comprising a ceramic sintered body. (4) The X-ray transmitting membrane holding frame, X-ray mask blank, or X-ray mask structure according to any one of claims 1 to 3, wherein the dust generation prevention treatment is performed by coating and/or impregnating an organic or inorganic binder. (5) The X-ray transparent membrane holding frame, X-ray mask blank, or X-ray mask structure according to any one of claims 1 to 3, wherein the dust generation prevention treatment is ceramic coating or metal plating. (6) X according to claims 1 to 3, wherein the holding frame also includes a reinforcing body.
A radiation transmitting membrane holding frame, an X-ray mask blank, or an X-ray mask structure.