JPH04179215A - Amorphous thin film and manufacture thereof - Google Patents

Abstract

PURPOSE:To make it possible to measure a stress of an amorphous thin film by an X-ray diffraction method or by a Raman scattering method by depositing a crystalline thin film or scattering crystalline fine particles on the amorphous thin film. CONSTITUTION:On a substrate 3, an SiN film 2 is deposited to the specified thickness and then polycrystalline Si is deposited in the specified thickness to form a crystalline film 1. After that, an SiN film is formed on the crystalline film 1. Or, after the polycrystalline Si film 1 is formed, the film 1 is processed to a beltlike one or islandlike one by photolithography and etching and then an SiN film is formed on the film 1. The crystalline film or particle is deformed by a stress which is applied by the SiN film. Therefore, the amount it deforms is measured by measuring X-ray diffraction or Raman scattering of a crystal of the crystalline film or particle. The stress of the SiN film can measured by measuring the amount the crystalline film or particle deforms.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to the structure of an amorphous thin film used in the manufacture of semiconductor devices and its manufacturing method.

(Prior Art) In order to respond to the miniaturization of semiconductor devices, a new phosphorography technique using X-rays is being studied. The mask used in XM phosphorography is Ta/SiN structure Xa for half-micron LSI by Toebanis Ogi
Mask Ta/SiN StructureXray M
asks for Sub-half-micron
LSI J Digest Off Papers, 1989
Second Microprocess Conference (Diges)
t' of Papersl 989 2nd Mic
roprocess Conf,) PP 94-95
It is usually manufactured using the structure and process shown in .

In other words, low pressure CVD was applied to a 3-inch diameter crystalline silicon substrate.
After that, a tantalum film of 0.65 μm was formed by a sputtering method, an SiO2 film was formed by an electron cycle tron resonance CvD method, and a resist film was applied, and the resist was removed by electron beam exposure. After forming films and turns, the SiO2 film is etched by dry etching, and the tantalum film is further etched using the 5IO2 film as a mask.

Next, the SiN film attached to the back side of the Si substrate was removed by wet etching, and the silicon substrate was further wet etched using the SiN film as a mask, so that the SiN film was supported in the hollow ring of the silicon substrate and further patterned on the SiN film. Tantalum membrane is now supported,
Obtain an X-ray mask.

At this time, in order to prevent the pattern of the tantalum film from becoming distorted or peeling off, as shown in the above-mentioned document (S
The stress of the iN film is 1 (stress) × (film thickness) 1 × 10 × 1
It is necessary to control the stress so that the stress is 0 dynA-rn and the stress is compressive.

(Problems to be Solved by the Invention) According to the conventional mask manufacturing method described above, it is necessary to accurately control the stress of the SiN film, for example, and for this purpose, it is necessary to measure the stress and feed it back. Generally, this stress is measured by measuring the warpage of the substrate, but after the SiN film is formed, SiN is applied to both sides of the silicon substrate.
for a membrane to form.

It is not possible to use the usual method of measuring the stress of such an amorphous film from the surface of the substrate.

Furthermore, in the conventional mask manufacturing method described above, the Si on the back side
It is possible to remove the N film by etching before forming the tantalum film, but this may contaminate the SiN film on the surface side, which is required before forming the tantalum film, and may easily cause peeling of the tantalum film above it. .

Furthermore, stress distributed within the plane cannot be measured by measuring stress by bending the substrate.

As described above, it is an object of the present invention to provide a thin film structure and a method for manufacturing the same, in which stress and its distribution can be measured during the manufacture of an amorphous thin film.

(Means for solving the problem) A crystalline thin film or fine particles are laminated or dispersed on an amorphous thin film.

(Function) By dispersing crystalline particles in an amorphous thin film that is the object of stress measurement, or by stacking a crystalline thin film on top of an amorphous thin film, X-ray diffraction or Raman It becomes possible to measure stress in amorphous thin films using scattering methods and the like.

(Example) FIG. 1, FIG. 2, and FIG. 3 are diagrams showing examples of the present invention, respectively. Here, a case will be described in which an SiN film, which is an amorphous film, is used as a thin film for an X-ray mask.

In the embodiment shown in FIG. 1, an amorphous thin film 2 to be subjected to stress measurement is provided on a substrate 3.
There is a crystalline film 1 inside.

In the embodiment shown in FIG. 2, a crystalline film 1', which is an analysis of the crystalline film 1 shown in FIG. 1, is replaced by an amorphous film 2.
Further, in the embodiment shown in FIG. 3, crystalline particles 1 are dispersed within an amorphous film 2. In the embodiment shown in FIG.

In order to be able to apply X-ray diffraction or Raman scattering to the stress measurement without impairing the function of the Xa mask thin film, the X-ray wavelength (~10X
) must have an X-ray absorption coefficient equal to or lower than that of SiN.

Such a substance is Si+ Be +A71203
A substance such as +5ICI BN can be used.

These substances are formed in the SiN film in the form of a crystalline thin film or thin film in the form of bands, islands, or particles. Since the crystalline film or particles formed in this way are deformed by the stress applied by the SiN film, the amount of deformation is measured by measuring X-ray diffraction or Raman scattering of this crystal, and thereby the SiN It becomes possible to measure the stress in the membrane.

Furthermore, by using X-ray diffraction or microscopic Raman scattering, which can limit the measurement to a minute area, it is also possible to measure the in-plane stress distribution.

Next, a method for manufacturing an amorphous film having the structure shown in FIGS. 1, 2, and 3 will be described for the case where the crystalline film is polycrystalline S1.

In order to obtain the structure shown in Fig. 1, the SiN film 2 is
After forming the SiN film, polycrystalline Si is formed to a certain thickness by low pressure CVD to form a crystalline film 1, and then an SiN film is further formed.

To obtain the structure shown in Fig. 2, the polycrystalline Si film 1 is
After forming polycrystalline S by photolithography and etching
J film 1 may be processed into a band shape or an island shape, and then a SiN film may be formed. In addition, when forming polycrystalline Si using an electron beam evaporation method, SiP tuttering method, ECR plasma CVD method, etc., which can form the polycrystalline silicon with directionality instead of low-pressure CVD, an appropriate shape is applied to the upper layer on the SiN film 2. The structure shown in FIG. 2 can be realized without using a hole, phosphorography, or etching process by forming the structure through a so-called metal mask having holes.

The structure shown in FIG. 3 can be easily realized by supplying crystalline fine particles l'' by an appropriate fine particle formation method during the formation of the SiN film 2.Such a method can also be used for materials other than Si. The same can be applied.

Although the thin film has been described above as being used as an X-ray mask thin film, it can also be used for other applications requiring stress control.

(Effects of the Invention) As described above in detail, according to the present invention, the structure is such that crystalline thin films or fine particles are laminated or dispersed in an amorphous thin film, so that X-ray diffraction, Raman scattering, etc. By this method, the stress distribution of a thin film can be measured regardless of the presence or absence of a substrate. Therefore, it is applicable to the production of thin films for X-ray masks, for example, which requires precise control of stress in amorphous thin films.

[Brief explanation of the drawing]

FIG. 1, FIG. 2, and FIG. 3 are diagrams showing examples of amorphous thin films according to the present invention, respectively. 1... Crystalline substance, 2... Amorphous thin film, 3... Semiconductor substrate. Patent applicant Oki Electric Industry Co., Ltd.

Claims (1)

[Claims] 1. An amorphous thin film containing a crystalline substance. 2. The amorphous thin film according to claim 1, wherein the crystalline substance is a continuous thin film. 3. The amorphous thin film according to claim 2, wherein the continuous crystalline thin film is laminated on the amorphous thin film. 4. The amorphous thin film according to claim 2, wherein the continuous crystalline thin film is disposed within the amorphous thin film. 5. The amorphous thin film according to claim 1, wherein the crystalline substance is in the form of particles and is substantially uniformly dispersed within the amorphous thin film. 6. The amorphous thin film according to claim 1, wherein the crystalline substance is a thin film piece and is substantially uniformly dispersed within the amorphous thin film. 7. A method for forming an amorphous thin film comprising a first step of forming an amorphous thin film on a semiconductor substrate and a second step of forming a crystalline thin film on the amorphous thin film. 8. The method according to claim 7, further comprising a third step of forming an amorphous thin film on the crystalline thin film. 9. The method of claim 8, wherein the crystalline thin film has substantially uniformly distributed apertures. 10. A method for forming an amorphous thin film, which comprises forming an amorphous thin film on a semiconductor substrate and substantially uniformly dispersing a crystalline substance in the amorphous thin film.