JP2897692B2 - Resist pattern forming method, antireflection film forming method, antireflection film, and semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a resist pattern using a novel anti-reflection film and a method for forming an anti-reflection film.
And a semiconductor device having the antireflection film.
In particular, the present invention relates to a method for forming a resist pattern by exposing a photoresist on an anti-reflection film formed on a base substrate with a single wavelength, and a thickness of the anti-reflection film, a reflection refractive index, and an absorption refractive index. Using a novel anti-reflection film suitable for optimizing optical conditions such as etc., the standing wave effect in the photoresist can be set to a predetermined value, and a resist that can form a fine resist pattern well Pattern forming method , antireflection film forming method, and having the antireflection film
The present invention relates to a semiconductor device .

[0002]

2. Description of the Related Art In photolithography technology, for example, the most advanced stepper (projection exposure machine) is currently K
Using rF excimer laser light (248 nm) as a light source,
A lens with an NA of about 0.37 to 0.42 is mounted (for example, Nikon NSR1505EX1, Canon FP
A4500). Research and development of design rule devices in the sub-half micron (0.5 μm or less) region have been studied using these steppers.

A stepper uses light of a single wavelength as an exposure light source. It is widely known that when exposure is performed at a single wavelength, a phenomenon called a standing wave effect occurs.
The reason why the standing wave is generated is that optical interference occurs in the resist film. That is, as shown in FIG.
And the reflected light R from the interface between the resist PR and the substrate S
This is because interference occurs in the film of the resist PR .

As a result, as shown in FIG. 2, the amount of light absorbed by the resist (vertical axis) changes depending on the resist film thickness (horizontal axis). In this specification, the amount of light absorbed by the resist refers to the amount of light absorbed by the resist itself, excluding surface reflection, absorption by the metal when metal is present, and the amount of light emitted from the resist. Means the amount of The amount of the absorbed light becomes the energy for light reflection of the resist. FIG. 2 shows a result obtained by forming a resist film (XP8843) on a silicon substrate and examining a change in the amount of absorbed light depending on the thickness of the resist film. As a light source for exposure, KrF of λ = 248 nm was assumed.

The degree of the change in the amount of absorbed light is shown in FIG.
As can be understood from the comparison between FIG. 4 and FIG. 2, 3 and 4, XP8843 (Shipley) is used for the resist, but the underlying substrates are Si, Al-Si, and W-Si, respectively. That is, the degree of change in the amount of absorbed light is determined by the complex amplitude reflectance (R) that takes into account multiple interference determined by the optical constants (n, k) of the underlying substrate and the optical constants (n, k) of the resist. ((R) indicates a vector quantity having a real part and an imaginary part).

Here, the optical constant n is a reflection refractive index, and k is absorption.
And the two optical constants n and k are given by
It can be determined by (1), (2) and (3). I = I _o exp (−αd) (1) α = 4πk / λ (2) n ^* = n−ik (3) (in the above formula, n ^* is a transmission absorption rate, λ is the wavelength of the incident light, I
Is the light intensity at a certain depth d, _Io is the light intensity of the incident light
Respectively. )

Further, in an actual device, as shown in FIG. 5, there are always irregularities on the substrate surface. For example, there is a protrusion In such as polysilicon. For this reason, when the resist film PR is applied, the thickness of the resist film differs between the upper part and the lower part of the step. That is, the resist film thickness _{d PR2} on the convex portion In is thinner than the resist film thickness _{d PR1} of the other portions.

[0008] It effect of standing wave varies by the thickness of the resist film are as above described, Therefore, change in the amount of light absorbed in the resist by being affected by the standing wave effect, come each change . As a result, the dimensions of the resist pattern obtained after the exposure and the phenomenon differ between the upper part and the lower part of the step. The effect of the standing wave effect on the pattern size becomes more pronounced as the pattern becomes finer when a stepper having the same wavelength and the same numerical aperture is used, and is a phenomenon that is common to any type of resist.

The effect of the standing wave effect on the pattern size becomes more pronounced as the pattern becomes finer when a stepper having the same wavelength and the same numerical aperture is used. FIG.
8 to Nikon NSR1505EX1 as a stepper
(Used exposure light source : λ = 248 nm, KrF excimer, N
A = 0.42) and XP8843 as a resist.
The effect of the standing wave effect when using (a chemically amplified resist of Shipley Microelectronics, Inc .; a polyvinylphenol-based resist containing a photoacid generator) is shown for each pattern size. Obviously, as the pattern becomes finer, the standing wave effect becomes more remarkable (the critical dimension shift CD-Shift of the 0.5 μm, 0.4 μm, 0.35 μm line and space pattern indicated by a circle in the figure). See also variation). 6 shows a case of a line and space pattern with an interval of 0.5 μm, FIG. 7 shows a case of a line and space pattern with an interval of 0.4 μm, and FIG. 8 shows a case of a line and space with an interval of 0.35 μm This is the case of a pattern, and the standing wave effect becomes more prominent as the size is reduced.

[0010] This tendency is a phenomenon that is commonly observed in any type of resist. The dimensional accuracy of a resist pattern in a photolithography process at the time of manufacturing a device such as a semiconductor device is generally ± 5%. In total, it is considered that the device can be used even if it is warmer than ± 5%. However, considering that variations due to other factors such as focus may occur, the pattern accuracy at the time of resist exposure is within ± 5%. It is desired to fit. This ± 5
In order to achieve% dimensional accuracy, it is essential to reduce the standing wave effect.

FIG. 9 shows a dimensional change (vertical axis) of the resist pattern with respect to a change in the amount of absorbed light in the resist film (horizontal axis). From FIG. 9, it can be seen that, for example, in order to manufacture a 0.35 μm rule device, the variation in the amount of light absorbed by the resist film is required to be within 6% of the range.

[0012]

In order to meet the above-mentioned demands, antireflection techniques are being actively studied in various fields. However, even if the material of the base substrate and the resist to be used are determined, it is not always easy to determine the conditions of the antireflection film that can obtain an appropriate antireflection effect in that case. .

For example, on a gate structure (for example, tungsten silicide (W
In the pattern formation on the (-Si) film), it is not determined under what conditions the antireflection film has a variation in the amount of light absorbed by the resist film, for example, in a range of 6% or less. Of course, no effective anti-reflective coating material on such W-Si has yet been found.

With respect to the structure using the W-Si material as a gate, a pattern is currently formed by a multilayer resist method or a die-containing resist. Therefore, it is considered essential to quickly establish an anti-reflection technology on W-Si.

In such a case, comprehensive conditions and specific conditions relating to an antireflection film for forming a stable fine pattern on any underlying substrate are determined by using any single wavelength as an exposure light source. If there is a means for obtaining the same, it is possible to find out, for example, under what conditions an antireflection film should be formed on W-Si as described above. However, such an approach has not yet been proposed.

The present invention has been made in view of the above circumstances, and when a resist pattern is formed on an arbitrary underlying substrate using light of an arbitrary single wavelength as an exposure light source, the resist pattern is fine. Even satisfactorily, a resist pattern forming method for forming a stable resist pattern, on the substrate, directly or through another layer
An anti-reflection film provided, wherein the exposure wavelength is 150 to 4
At 50 nm, a specific reflection refractive index n, absorption refractive index
k and silicon nitride based film with specific thickness
Antireflection film and a plurality of layers having the antireflection film
It is an object of the present invention to provide a semiconductor device comprising:

[0017]

To achieve the above object, the present invention provides a semiconductor device having a multilayer structure,
Formed directly or via another layer on the underlying substrate
Photo-resist on the anti-reflection film composed of silicon nitride film
The Rejisutopa turn was exposed by a single wavelength resist
A method of forming a resist pattern, comprising:
Forming an antireflection film made of a silicon-based film on the base substrate;
Resist in the photoresist at the time of exposure, depending on the type of
Minimum variation in standing wave effect due to film thickness variation
The reflection refractive index n and the absorption refraction of the antireflection film under the following conditions:
While adjusting the film forming conditions so that the ratio k and the film thickness are obtained.
A method of forming a resist pattern having a step of forming, 該Re
Silicon nitride based on distaste pattern forming method
An antireflection film composed of a film, and having the antireflection film
A semiconductor device is provided.

[0018] In the present invention, the silicon nitride film _(also referred to as SiN) Si _x N y is a film may comprise such as hydrogen as an optional component.

The surface of the base substrate is made of silicon.
It is possible to use a material composed of a phosphine-based material. Said
Silicon-based materials include single-crystal silicon and polycrystalline silicon.
Examples of capacitors, amorphous silicon, doped polysilicon, etc.
Can be shown.

The base substrate has a high melting point surface.
Made of metal or refractory metal silicide-based material
Can be used. The high melting point metal or high melting point
As the metal silicide-based material, for example, tungsten
And tungsten silicide.

Further , the surface of the base substrate is
It is also possible to use one composed of low melting point metallic materials.
You. Examples of the low melting point metal-based material include aluminum and aluminum.
Luminium-silicon alloy, aluminum-silicon-
Examples thereof include copper alloy, copper, and copper alloy.

In the present invention, the surface of the base substrate has a high melting point.
In the case of metal or refractory metal silicide material,
As the anti-reflection film, the exposure wavelength is 150-450 nm.
In this case, the reflection refractive index n is 1.0 or more and 3.6 or less,
Folding ratio k is 0.11 or more and 0.75 or less, and film thickness is 10 nm or less.
100 nm or less due to fluctuations in the thickness of the resist film .
Anti-reflection so that the dispersion of the standing wave effect
It is more preferable to form a stop film.

Alternatively, in the present invention, the surface of the underlying substrate is
For refractory metals or refractory metal silicide materials
Has an exposure wavelength of 150 to 450 as the antireflection film.
nm, the reflection refractive index n is 1.7 or more and 5.9 or less,
The absorption refractive index k is a positive number of 0.51 or less, and the film thickness is 25
nm or more and 100 nm or less.
So that the dispersion of the standing wave effect due to
It is more preferable to form an antireflection film.

In the present invention, the surface of the base substrate has a low melting point.
In the case of a metal-based material, an exposure wave is used as the antireflection film.
When the length is 150 to 450 nm, the reflection refractive index n is 1.
3 or more and 3.6 or less, absorption refractive index k is 0.2 or more and 1.5 or less
Below, the film thickness is 10 nm or more and 70 nm or less,
Minimum variation in standing wave effect due to film thickness variation
It is more preferable to form an anti-reflection film so that
No.

Alternatively, in the present invention, the surface of the underlying substrate is
In the case of a low melting point metal-based material, as the antireflection film,
When the exposure wavelength is 150 to 450 nm, the reflection refractive index n
Is 1.9 or more and 5.9 or less, and the absorption refractive index k is 0.2 or more.
A positive number of 0.75 or less, and a film thickness of 25 nm or more and 90 n
m or less, and the standing wave effect due to the fluctuation of the resist film thickness
An anti-reflective coating to minimize the variation of the fruits
Is more preferable.

In the present invention, the surface of the underlying substrate is made of silicon.
In the case of a radiation-based material, the exposure wavelength
Is 150 to 450 nm, and the reflection refractive index n is 1.8.
Not less than 2.6 and absorption refractive index k is not less than 0.1 and not more than 0.8
Below, the film thickness is 20 nm or more and 150 nm or less,
The variation of the standing wave effect due to the variation of
It is more preferable to form an anti-reflection coating to
No.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the method for forming an antireflection film and the method for forming a resist pattern according to the present invention, before the antireflection film is actually formed, the method depends on the type of the base substrate.
The reflection refractive index n, the absorption refractive index k, and the film thickness of the antireflection film are obtained by simulation under the condition that the standing wave effect in the photoresist at the time of exposure becomes a predetermined value, and the reflection refractive index obtained by the simulation is obtained. An antireflection film composed of a silicon nitride-based film is obtained by the above simulation while adjusting the film formation conditions, directly or through another layer, on the surface of the base substrate so as to approach n and the absorption refractive index k. It is preferable that the film be formed to have a film thickness substantially equal to the film thickness. In this case, the source gas preferably contains a substance containing at least a hydrogen element.

The above-mentioned new antireflection film was determined by the following means. (I) For a resist film having an arbitrary thickness,
Contour lines of the amount of light absorbed in the resist film when the optical conditions (n, k) of the antireflection film are continuously changed (however, the thickness of the antireflection film is fixed) are obtained. (II) In the result of the contour line of the amount of absorbed light in the resist at the thickness of each resist film obtained in (I) above, a common region where the difference in the amount of absorbed light is minimized is found, and the optical conditions limited by this common region Is the optical condition (n, k) at the film thickness of the antireflection film determined in (I). (III) The above operations (I) and (II) are repeated while changing the thickness of the anti-reflection film, and the optical constants (n, k) of each optimum condition for each thickness of the anti-reflection film are obtained. (IV) An anti-reflection film of an actual material having an optical constant under the optimum condition obtained in the above (III) is found.

Next, with reference to the drawings, the above-mentioned means (I) to determine the comprehensive conditions of the antireflection film used in the present invention.
(IV) will be described more specifically. Between the maximum value of the standing wave effect, or resist film thickness between the minimum value, when the refractive index of the resist and n _PR, the wavelength of the exposure light is lambda, it is given by λ / 2n _PR (see FIG. 10) . Assuming an antireflection film ARL between the resist and the underlying substrate, its thickness d _ar and optical constants are n _ar and k
_arl . Focusing on the film thickness at a certain point (for example, the film thickness at which the standing wave effect is maximized) in FIG. 10, the film thickness d _ar of the antireflection film is fixed, and n _ar and k _ar are fixed.
Is changed, the amount of light absorbed by the resist film at that point changes. When this changing locus, that is, the contour line of the amount of absorbed light is obtained, the result is as shown in FIG. For other different resist film thicknesses d _PR , at least based on a film thickness that maximizes or minimizes the standing wave effect, λ /
Repeating for 4 places at 8n _PR intervals,
12 to 14 corresponding to FIG. 11 are obtained (FIGS. 11 to 11).
FIG. 14 shows that the antireflection film thickness is set to 20 nm and the resist film thicknesses are 985 nm, 1000 nm, 1018 nm,
The result is 1035 nm). The above corresponds to the above-mentioned means (I).

The common regions in the graphs of FIGS. 11 to 14 show regions where the amount of absorbed light in the resist film does not change even if the resist film thickness changes for a specific antireflection film thickness. . That is, the common area is an area where the standing wave effect is minimized and the antireflection effect is the highest.
Therefore, such a common area is found. The common area can be found, for example, simply by superimposing the respective figures (graphs) and taking the common area (of course, the common area may be searched by a computer). This corresponds to the above means (II). Next, the above is repeated by continuously changing the thickness d of the antireflection film. For example, until the first step,
Assuming that the operation is performed with d = 20 nm, the above is repeated while changing d. Thereby, the film thickness d _{ar of the} antireflection film and the optical constant n that minimize the standing wave effect
_arl , _kall conditions can be specified. This corresponds to the above means (III). The type of film that satisfies the conditions (film thickness, optical constant) to be satisfied by the antireflection film specified above is found by measuring the optical constant of each film type in exposure light. This corresponds to the means (IV).

The above method is applicable in principle to all wavelengths and all underlying substrates. The above (I) to (I)
By means other V), was examined for anti-reflection film which can be suitably used in the process according to the present invention, a silicon film (Si _x N _y film nitride) has been found to be particularly suitable.

The optical conditions of this film can be greatly changed depending on the film forming conditions, and the standing wave effect obtained by the above-described method is changed by the variation in the thickness of the resist film.
It is possible to easily form an anti-reflection film in accordance with the optical conditions of the anti-reflection film so as to minimize the stickiness .

This antireflection film can be easily formed by various CVD methods. For example, this film is formed by using a parallel plate plasma CVD method, an ECR plasma CVD method, or a bias ECR plasma CVD method, and using a microwave and a silane-based gas and a gas containing nitrogen (for example, SiH ₄ + NH ₃ ). Or a gas containing silane-based gas and nitrogen (for example, SiH ₂ Cl ₂ + NH
_The film can be formed using the mixed gas of ₃ ). At that time, an argon Ar gas, an N ₂ gas, or the like can be used as a buffer gas.

Further, these _Si x _{N y} film, a resist as a _{mask, CF 4, CHF 2, C} 2 F 6, C
_{4 F 8, SF 6, S} 2 F 2, the NF ₃ series gas as an etchant, by the addition of Ar RIE with increased ionic, can be easily etched. That RIE
Is preferably performed under a pressure of about 2 Pa and applying a power of about 10 to 100 W. The flow rate of the gas during RIE is not particularly limited, but is preferably 5 to 70 SCCM.

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below. However, needless to say, the present invention is not limited by the following examples. Embodiment 1 This embodiment is an embodiment for forming a stable resist pattern on a W-Si film by using KrF excimer lithography. In the present embodiment, before actually forming a resist pattern using an anti-reflection film, the following method is used to optimize the optimal optical conditions of the anti-reflection film capable of minimizing the standing wave effect in the photoresist and The film thickness was determined.

(1) W-Si without an anti-reflection film
An XP8843 resist (Shipley Microelectronics Co., Ltd.) is applied on the film, and KrF having a wavelength of 248 nm is applied.
FIG. 15 shows the standing wave effect when exposing and developing with an excimer laser beam. From FIG. 15, the standing wave effect is about ± 2.
0%. (2) In FIG. 15, the maximum value of the standing wave effect is, for example, when the resist film thickness is 985 nm. Focusing on the resist film thickness of 985 nm, and setting the thickness of the antireflection film to 30 nm
FIG. 16 shows changes in the amount of absorbed light in the resist film (contours of the amount of absorbed light) with respect to changes in the optical constants n _ar and k _ar of the antireflection film. (3) a resist film thickness of 1000 nm, 1017.5 nm,
The results of repeating the above (2) for each of 1035 nm are shown in FIGS. 17, 18, and 19, respectively. (4) As a result of _finding the common area in FIGS.
= 4.9, k _ar = 0.1 or n _ar = 2.15, k _ar = 0.67
I got That is, when the thickness of the anti-reflection film is 30 nm, the conditions to be satisfied by the optimum anti-reflection film are n _ar = 4.9, k _ar = 0.1 or n _ar = 2.15, k _ar = 0. .67
It is.

When the standing wave effect was obtained using these conditions, the results shown in FIGS. 20 and 21 were obtained. 20 and 21, the standing wave effect was extremely small, and was about ± 1% in each case. The standing wave effect was reduced to about 1/20 of that without the anti-reflection film. In addition,
The optical conditions of the antireflection film are different between FIG. 20 and FIG. (5) The above operations (2) to (4) are performed when the thickness of the anti-reflection film is set to 30 nm. By repeatedly performing 2) to (4), the optimum condition of the antireflection film according to the thickness of the antireflection film is obtained. The results obtained are shown in FIGS. As shown in FIGS. 22 and 23, for the solution (Value) 1, the reflection refractive index n is 1.2 or more and 3.4 or less, and the absorption refractive index k is 0.16 or more and 0.1 or less.
A film having a thickness of not more than 72 and a thickness of not less than 10 nm and not more than 100 nm is an optimal antireflection film.
e) As for an antireflection film, an antireflection film having a reflection refractive index n of 1.9 or more and 5.7 or less and an absorption refractive index k of 0 or more and 0.46 or less is an optimal antireflection film. It has been found. Antireflection films having n and k matching the curves shown in FIGS. 22 and 23 are most preferable, but not necessarily on the curves, and n is ± 0.6, preferably ± 0.2, and k is Is within the range of ± 0.3, preferably ± 0.2, more preferably 0.15, and still more preferably ± 0.05.

(6) A spectroscopic ellipsometer (SOPRA, “Moss”) is used to determine whether there is a film type that satisfies the conditions to be satisfied by the antireflection film obtained in (5).
System "). As a result, FIG.
As shown in FIG. 4, it was found that n and k changed in accordance with the flow rate ratio of SiH ₄ and NH ₃ and the microwave output, and the film was formed under the conditions circled in FIG. If S
It was found that iN (silicon nitride) completely satisfied the conditions of FIGS. That is, preferably, n =
2.4 ± 0.6, k = 0.7 ± 0.2, film thickness d = 25n
The use of m is ± 10nm Si _x N _y as the anti-reflection film, it is expected that it is possible to minimize the standing wave effect.

Next, the Si _x N with the above optical conditions and film thickness is used.
_It was confirmed whether or not the standing wave effect was actually reduced by forming the _y film. As shown in FIG. 25, on the silicon substrate S, by laminating a W-Si which is a refractory metal silicide, on which, Si _x N _y consisting film antireflection film AR
L was formed. That is, using an ECR-CVD apparatus,
A 23.8 nm SiN _x film was formed. Its _Si x _{N y} reflection refractive index n of the antireflection film ARL consisting film is is 2.36, the absorption refractive index k was 0.53. The _Si x N
A photoresist PR made of XP8843 was formed on the antireflection film ARL made of the _y film, and the result of examining the standing wave effect is shown in Example 1 in FIG. For comparison, the result of similarly examining the standing wave effect except that the antireflection film was not formed is also shown as Comparative Example 1.

In the first embodiment, the standing wave effect is approximately ± 1.8.
%, And the standing wave effect was reduced to about 1/12 compared to the case of Comparative Example 1 in which the antireflection film was not used (± 21%). In the structure shown in FIG.
The R a line width of 0.35μm rule, lambda as an exposure light source
When photolithography was performed using a KrF laser of = 248 nm, a favorable resist pattern close to a mask pattern was obtained. Thereafter, the underlying substrate was etched using the resist pattern as a mask. First, Si
etching of _x N _{y film,} CHF 3 _(50~100SC
CM) + O ₂ (3-20 SCCM) gas system
Reactive etching (RI) in which ionicity is increased by applying a power of about 100 to 1000 W under a pressure of about Pa
A desired pattern was etched by performing the etching according to the method E). Next, FIG.
Was etched by RIE or the like using the photoresist PR of a predetermined pattern as a mask. A W-Si gate G having a good fine pattern to which a fine resist pattern was transferred was obtained.

[0041] EXAMPLE 2 In this example, an antireflection film made of Si _x N _y film, except that was formed by the following method, in the same manner as in Example 1, to process the underlying substrate. That is, in this embodiment,
Using a parallel plasma CVD method, an ECR plasma CVD method, or a bias ECR plasma CVD method, using microwave (2.45 GHz), SiH ₄ + NH ₃
Mixed gas, or using a _SiH 2 _Cl 2 + NH ₃ mixed gas was formed an antireflection film made of _Si x _{N y} film.
The anti-reflection film, before forming the resist may be performed 0 ₂ plasma treatment. By performing this plasma treatment, deactivation of the acid below the resist is prevented, and tailing or overhang of the pattern of the chemically amplified resist is prevented.

[0042] EXAMPLE 3 In this example, an antireflection film made of Si _x N _y film, except that was formed by the following method, in the same manner as in Example 1, to process the underlying substrate. That is, in this embodiment,
Parallel plate plasma CVD, ECR plasma CVD
And a mixed gas of SiH ₄ + NH ₃ or a mixed gas of SiH ₂ Cl ₂ + NH ₃ using microwave (2.45 GHz) using a bias ECR plasma CVD method,
By using the Ar or _{N 2} as the buffer gas, Si _x
It was deposited antireflection film consisting of N _y film.

[0043] EXAMPLE 4 In this example, an antireflection film made of Si _x N _y film, except that was formed by the following method, in the same manner as in Example 1, to process the underlying substrate. That is, in this embodiment,
Using parallel plasma CVD, ECR plasma CVD, or bias ECR plasma CVD, Si
H ₄ + NH ₃ mixed gas or SiH ₂ Cl ₂ + NH
Using ₃ mixed gas was formed an antireflection film made of _Si x _{N y} film.

[0044] Example 5 In this example, an antireflection film made of Si _x N _y film, except that was formed by the following method, in the same manner as in Example 1, to process the underlying substrate. That is, in this embodiment,
Parallel plate plasma CVD, ECR plasma CVD
Method, bias ECR plasma CVD method,
₄ + NH ₃ mixed gas or SiH ₂ Cl ₂ + NH ₃
Mixed with gas, with the Ar or _{N 2} as the buffer gas, it was formed an antireflection film made of _Si x _{N y} film.

[0045] EXAMPLE 6 In this example, an antireflection film made of Si _x N _y film, by the following procedure, except that etching the resist pattern as a mask, in the same manner as in Example 1, a base substrate processed. That is, in the present embodiment, _Si x _N etching _{y film, C 4 F 8 (30~70SCCM)} + C
Using a gas system of HF ₃ (10 to ₃₀ SCCM), 2 Pa
Under a pressure of about 100 to 1000 W, a reactive etching method of increasing the ionicity by applying a power of about 100 to 1000 W
The desired pattern was etched.

[0046] In Example 7 This example, the anti-reflection film made of Si _x N _y film, by the following procedure, except that etching the resist pattern as a mask, in the same manner as in Example 1, a base substrate processed. That is, in this embodiment, the etching of the _Si x _{N y film,} using a gas system of S ₂ F ₂ (5~30SCCM), under a pressure of about 2 Pa, 100 to 1000 W
A desired pattern was etched by a reactive etching method in which ionicity was increased by applying a certain amount of power.

Embodiment 8 In this embodiment, as shown in FIG. 27, a low melting point metal material G such as Al, Al-Si, Al-Si-Cu is laminated on a silicon substrate S, and The anti-reflection film ARL and a silicon oxide film Ox such as SiO ₂ are stacked as required, and the photoresist PR is subjected to photolithography using KrF excimer lithography. At this time, in this embodiment, as the antireflection film, use of _Si x _{N y} film. As Al-Si, in addition to a commonly used Al-Si alloy containing 1% by weight of Si, an alloy containing less or more Si can be preferably used. Al-Si-Cu
For example, Si is about 1% by weight and Cu is preferably about 0.1 to 2% by weight.
Not limited to these. Typically, 1% by weight of Si, Cu
It is a 0.5% by weight Al-Si-Cu alloy.

As an anti-reflection film used on a low melting point metal base substrate such as Al, Al-Si, Al-Si-Cu, etc.
i _x N _y film was found technique, material and the reflectivity of the underlying substrate, except that different, it was carried out in the same manner as in Example 1. That is, the following method was used. (1) Al, Al-Si, A without an anti-reflection film
An XP8843 resist (Shipley Microelectronics Co., Ltd.) was applied on an l-Si-Cu substrate, and a wavelength of 2
Exposure and development were performed using a 48 nm KrF excimer laser beam. FIG. 3 shows the standing wave effect at this time. According to FIG.
The standing wave effect is about ± 29.6%. (2) In FIG. 3, the maximum value of the standing wave effect is, for example,
This is when the resist film thickness is 982 nm. Focusing on the resist film thickness of 982 nm, and setting the thickness of the antireflection film to 30 nm
In FIG. 28, contour lines of the amount of light absorbed in the resist film with respect to changes in the optical constants n _ar and k _ar of the antireflection film are shown in
Shown in

(3) Resist film thickness 1000 nm, 101
As a result of repeating the above (2) for each of 8 nm and 1035 nm, the results are shown in FIGS. 29, 30, and 31, respectively. (4) As a result of _finding the common area of FIGS. 28 to 31, n _ar = 4.8, k _ar = 0.45 or n _ar = 2.0, k _ar = 0.8. That is, when the thickness of the anti-reflection film is 30 nm, the conditions to be satisfied by the optimum anti-reflection film are n _ar = 4.8, k _ar = 0.45, or n _ar = 2.0, k _ar = 0. .8. When the standing wave effect is obtained by using these conditions, FIGS.
Were obtained. 33 and 34, the standing wave effect was extremely small, and in each case, the range was about 1% or less. The standing wave effect was reduced to about 1/60 of that without the anti-reflection film shown in FIG.
32 and 33 differ in the optical conditions of the antireflection film.

(5) The above operations (2) to (4) are performed when the thickness of the antireflection film is set to 30 nm. Also, (2)
By repeating (4) to (4), the optimum condition of the antireflection film according to the thickness of the antireflection film is obtained. FIG. 22 shows the obtained result.
As shown in FIG. As shown in FIGS. 22 and 34, the solution (Val
ue) 1; as a reflection preventing film, a reflection refractive index n
Is not less than 1.2 and not more than 3.4, and the absorption refractive index k is 0.4
Not less than 1.4 and a film thickness of not less than 10 nm and not more than 100 nm.
The following are the optimal antireflection films, and the solution (Va
lue) 2, as an antireflection film, the reflection refractive index n is 1.9 or more and 5.7 or less, and the absorption refractive index k is 0.1 or less.
It has been found that those having a value of not less than 2 and not more than 0.62 are optimum antireflection films. Antireflection films having n and k matching the curves shown in FIGS. 22 and 23 are most preferable, but not necessarily on the curves, and n is ± 0.6, preferably ± 0.2, and k is Is within the range of ± 0.3, preferably ± 0.2, more preferably 0.15, and still more preferably ± 0.05.

(6) Using a spectroscopic ellipsometer (SOPRA), an investigation was made to determine whether or not there was a film type that satisfies the conditions to be satisfied by the antireflection film obtained in (5) above. As a result, in response to the deposition conditions for depositing by CVD a Si _x N _y film, the optical constants were found to exhibit a change shown in FIG. 35. The region indicated by a circle in FIG. 35 satisfies the conditions of FIGS. That is, preferably, the reflection refractive index n = 2.1 ± 0.6 and the absorption refractive index k =
0.7 ± 0.2, thickness d = 30 nm ± 10 nm
The use of i _x N _y film as an antireflection film, it is expected that it is possible to minimize the standing wave effect.

Next, the Si _x N with the above optical conditions and film thickness is used.
_It was confirmed whether or not the standing wave effect was actually reduced by forming the _y film. As shown in FIG. 27, a low-melting-point metal material layer G such as Al, Al-Si, or Al-Si-Cu is laminated on a silicon substrate S. Anti-reflection film AR made of a Si _x N _y film
L was formed. That is, using an ECR-CVD apparatus,
Flow rate ratio of SiH ₄ / NH ₃ is, Si _x under the condition of 0.83
The N _y film was about 25nm deposition. Its _Si x _{N y} reflection refractive index n of the antireflection film ARL consisting film is 2.08,
The absorption refractive index k was 0.85. On the antireflection film ARL made from the _Si x _{N y} film, a photoresist PR consisting XP8843, shows the results of examining the standing wave effect in Example 8 in FIG. 36. For comparison, a result of similarly examining the standing wave effect except that the antireflection film was not formed is also shown as Comparative Example 2.

In the eighth embodiment, the standing wave effect is about ± 0.5.
%, And the standing wave effect was reduced to about 1/60 as compared with the case of Comparative Example 2 in which the antireflection film was not used (± 30%). In the structure shown in FIG.
The R a line width of 0.35μm rule, lambda as an exposure light source
When photolithography was performed using a KrF laser of = 248 nm, a favorable resist pattern close to a mask pattern was obtained.

Thereafter, the underlying substrate was etched using the resist pattern as a mask. First, the etching of the _Si x _{N y film,} CHF 3 _(50~100SCCM) + O
₂ Using a gas system of (3 to 20 SCCM), etching is performed by a reactive etching (RIE) method in which a power of about 100 to 1000 W is applied under a pressure of about 2 Pa to increase ionicity, and a desired etching is performed. The pattern was etched. Next, the low-melting-point metal material layer G, which is a metal wiring material shown in FIG. 27 as a base substrate, was etched by RIE or the like using a photoresist PR of a predetermined pattern as a mask. A good fine pattern metal wiring layer to which the fine resist pattern was transferred was obtained.

Embodiment 9 In this embodiment, a diagram showing the relationship between the antireflection film thickness shown in Embodiment 8 and the optical characteristics to be satisfied by the optimum antireflection film (FIG. 2).
2, the value on the curve in FIG. 34), or for n, the value on the curve ± 0.3, for k, the value on the curve ±
The anti-reflection film made of Si _x N _y film within a range of 0.3, it was formed by the following method. That is, in the present embodiment, in the parallel plate type plasma CVD method, the ECR plasma CV
Method D, or by using a bias ECR plasma CVD method, a microwave (2.45 GHz), SiH ₄
+ NH ₃ mixed gas or SiH ₂ Cl ₂ + NH ₃ mixed gas was used to form a film. By such a CVD method,
By adjusting the gas flow ratio, the values on the curves in the diagrams (FIGS. 22 and 34) showing the relationship between the antireflection film thickness and the optical characteristics to be satisfied by the optimum antireflection film, or n
Value ± 0.3 on the curve with respect to, could be satisfactorily deposited antireflection film made of Si _x N _y film within a range of values ± 0.3 on the curve with respect to k.

Embodiment 10 In this embodiment, the values on the curves in the diagrams (FIGS. 22 and 34) showing the relationship between the antireflection film thickness and the optical characteristics to be satisfied by the optimum antireflection film shown in the eighth embodiment. Or, for n, the value on the curve ± 0.3, for k, the value on the curve ±
The anti-reflection film made of Si _x N _y film within a range of 0.3, it was formed by the following method. That is, in the present embodiment, in the parallel plate type plasma CVD method, the ECR plasma CV
Method D, or by using a bias ECR plasma CVD method, a microwave (2.45 GHz), SiH ₄
+ NH ₃ mixed gas or SiH ₂ Cl ₂ + NH ₃ mixed gas and Ar or N ₂ as a buffer gas were used to form a film. FIGS. 22 and 3 show the relationship between the antireflection film thickness and the optical characteristics to be satisfied by the optimum antireflection film by adjusting the gas flow ratio by such a CVD method.
Curve on values in 4), or, better anti-reflection film made of Si _x N _y film within a range of values ± 0.3 on the curve with respect to the value ± 0.3, k on the curve with respect to the n A film could be formed.

Embodiment 11 In this embodiment, the relationship between the antireflection film thickness shown in Embodiment 8 and the optical characteristics to be satisfied by the optimum antireflection film (FIG. 2)
2, the value on the curve in FIG. 34), or for n, the value on the curve ± 0.3, for k, the value on the curve ±
The anti-reflection film made of Si _x N _y film within a range of 0.3, it was formed by the following method. That is, in this embodiment, in the parallel plate type plasma CVD method, the ECR plasma CV
Using a D method or a bias ECR plasma CVD method, a mixed gas of SiH ₄ + NH ₃ or SiH ₂ Cl
_A film was formed using a ₂ + NH ₃ mixed gas. Such CV
By adjusting the gas flow ratio by the method D, the values on the curves in the diagrams (FIGS. 22 and 34) showing the relationship between the antireflection film thickness and the optical characteristics to be satisfied by the optimum antireflection film, or n value ± 0.3 on the curve with respect to, could be satisfactorily deposited antireflection film made of Si _x N _y film within a range of values ± 0.3 on the curve with respect to k.

Embodiment 12 In this embodiment, the values on the curves in the diagrams (FIGS. 22 and 34) showing the relationship between the antireflection film thickness and the optical characteristics to be satisfied by the optimum antireflection film shown in the eighth embodiment. Or, for n, the value on the curve ± 0.3, for k, the value on the curve ±
The anti-reflection film made of Si _x N _y film within a range of 0.3, it was formed by the following method. That is, in the present embodiment, in the parallel plate type plasma CVD method, the ECR plasma CV
Using a D method or a bias ECR plasma CVD method, a mixed gas of SiH ₄ + NH _{3 or} SiH ₂ C
A film was formed using l ₂ + NH ₃ mixed gas and Ar or N ₂ as a buffer gas. By adjusting the gas flow ratio by such a CVD method, the values on the curves in the diagrams (FIGS. 22 and 34) showing the relationship between the anti-reflection film thickness and the optical characteristics to be satisfied by the optimum anti-reflection film, Or
value ± 0.3 on the curve with respect to n, could be satisfactorily deposited antireflection film made of Si _x N _y film within a range of values ± 0.3 on the curve with respect to k.

[0059] In Example 1 three embodiments, the anti-reflection film made of Si _x N _y film, by the following procedure, except that etching the resist pattern as a mask, in the same manner as in Example 8, underlying substrate Was processed. That is, in the present embodiment, _Si x _N etching _{y film, C 4 F 8 (30~70SCCM)} + C
Using a gas system of HF ₃ (10 to ₃₀ SCCM), 2 Pa
Under a pressure of about 100 to 1000 W, a reactive etching method of increasing the ionicity by applying a power of about 100 to 1000 W
The desired pattern was etched.

[0060] In Example 14 In this example, an antireflection film made of Si _x N _y film, by the following procedure, except that etching the resist pattern as a mask, in the same manner as in Example 8, the underlying substrate processed. That is, in this embodiment, the etching of the _Si x _{N y film,} using a gas system of S ₂ F ₂ (5~30SCCM), under a pressure of about 2 Pa, 100 to 1000 W
A desired pattern was etched by a reactive etching method in which ionicity was increased by applying a certain amount of power.

Embodiment 15 In this embodiment, as shown in FIG. 37, a silicon base substrate G such as monocrystalline silicon, polycrystalline silicon, amorphous silicon, or doped polysilicon is used as a base substrate S. An anti-reflection film ARL and, if necessary, a silicon oxide film Ox such as SiO ₂ are laminated thereon, and the photoresist PR is subjected to photolithography using KrF excimer lithography. At this time, in this embodiment, as the antireflection film, use of _Si x _{N y} film.

[0062] Single crystal silicon, polycrystalline silicon, amorphous silicon, as an anti-reflection film used for a silicon-based substrate, such as doped polysilicon, technique found Si _x N _y film, the material and reflection of the underlying substrate The procedure was performed in the same manner as in Example 1 except that the ratios were different. That is, the following method was used. (1) XP88 on a Si-based substrate without an anti-reflection film
43 resist (Shipley Microelectronics Co., Ltd.) was applied and developed with an exposure machine using a KrF excimer laser beam having a wavelength of 248 nm as a light source. FIG. 38 shows the standing wave effect at this time. From FIG. 38, the standing wave effect is
About ± 20%. (2) In FIG. 38, the maximum value of the standing wave effect is, for example, when the resist film thickness is 985 nm. Focusing on the resist film thickness of 985 nm, and setting the thickness of the antireflection film to 30 nm
_Then , the change in the amount of absorbed light in the resist film with respect to the change in the optical constants n _ar and k _ar of the antireflection film is determined. (3) Another plurality of resist film thicknesses were obtained, and the above (2) was repeated for each of them. (4) The results are shown and these common areas are determined.
Such an operation is determined for various antireflection film thicknesses, whereby the optimum value of the optical constant (n
Value, k value). For example, if the thickness of the anti-reflection film is 32
The optical conditions to be satisfied by the optimum anti-reflection film when nm is set are n _arr = 2.0 and k _ar = 0.55. The optical conditions to be satisfied by the optimum anti-reflection film when the thickness of the anti-reflection film is 100 nm are n _ar = 1.9 and k _ar = 0.35.

When the standing wave effect was obtained using the above two conditions, the results shown in FIGS. 39 and 40 were obtained. FIG. 39, FIG.
, The standing wave effect indicated by the optimum value was extremely small, and in each case, the range was about 1% or less. The standing wave effect was reduced to about 1/20 or less as compared with the case without the antireflection film.

(5) The above operations (2) to (4) are performed when the thickness of the antireflection film is set to 32 nm and 100 nm.
By repeating (2) to (4), the optimum condition of the anti-reflection film according to the thickness of the anti-reflection film is obtained. For example, when the underlying substrate is made of polysilicon, amorphous silicon, or doped silicon and the thickness of the antireflection film is 33 nm, the optical conditions to be satisfied by the optimal antireflection film are n _ar = 2.01, k _ar = 0.62. When the standing wave effect was obtained using the above conditions, the result shown in FIG. 41 was obtained. In FIG. 41, the standing wave effect indicated by the optimum value is extremely small, and the range is about 1% or less. The standing wave effect was reduced to about 1/20 or less as compared with the case without the antireflection film.

(6) Using a spectroscopic ellipsometer (SOPRA), it was examined whether or not a film type satisfying the conditions to be satisfied by the antireflection film obtained in the above (5) was present. As a result, the optical constants were found to exhibit a change shown in FIG. 42 corresponds to Si _x N _y film deposition conditions for depositing by CVD. The area indicated by a circle in FIG. 42 satisfies the above condition (4).

[0066] That is, as a region shown in FIG. 42 ○, by setting the conditions of CVD, if forming the antireflection film made of Si _x N _y film, the reflection refractive index n and the absorption refractive index k is n _ar = 2.0, k _ar = 0.55, which is optimal when the thickness of the anti-reflection film is 32 nm, or n _ar = _1.1, which is optimal when the thickness of the anti-reflection film is 100 nm.
9, k _ar = 0.35, or the thickness of the antireflection film is 3
N _ar = 2.01, k _ar = optimized at 3 nm
It approaches 0.62. The allowable range of n is ± 0.6, k
Is ± 0.3, and the allowable range of the film thickness is ± 10 nm.

As a result, as shown in FIG. 37, on the undersubstrate G made of a silicon-based material,
A sign conditions, by forming a reflection preventing film consisting of Si _x N _y film, thereby forming a photoresist PR directly or via the silicon oxide film Ox thereon, when performing the photolithography process of the photoresist PR In addition, the standing wave effect can be minimized.

Actually, with the structure shown in FIG. 37, photolithography was performed using a photoresist PR with a line width of 0.35 μm rule and a KrF laser of λ = 248 nm as a light source for exposure. However, a good resist pattern close to the mask pattern was obtained. Thereafter, the underlying substrate was etched using the resist pattern as a mask. First, the etching of the _Si x _{N y film,} CHF 3 (1:50 to
Using a gas system of (00 SCCM) + O ₂ (3 to 20 SCCM), etching is performed by a reactive etching (RIE) method in which a power of about 100 to 1000 W is applied under a pressure of about 2 Pa to increase ionicity. ,
The desired pattern was etched.

Next, the surface of the underlying substrate G made of a silicon-based material shown in FIG. 37 as the underlying substrate was etched by RIE or the like using a photoresist PR of a predetermined pattern as a mask. A good fine pattern to which the fine resist pattern was transferred was obtained.

[0070] In Example 16 In this example, the Si _x N _y film shown in Examples 15, except that was formed by the following method, in the same manner as in Example 15, to form an antireflective film. That is, in this embodiment,
Parallel plate plasma CVD, ECR plasma CVD
SiH ₄ using a microwave (2.45 GHz) using a bias ECR plasma CVD method or a bias ECR plasma CVD method.
+ NH ₃ mixed gas or SiH ₂ Cl ₂ + NH ₃ mixed gas was used to form a film.

[0071] In Example 17 In this example, the Si _x N _y film shown in Examples 15, except that was formed by the following method, in the same manner as in Example 15, to form an antireflective film. That is, in this embodiment,
Parallel plate plasma CVD, ECR plasma CVD
SiH ₄ using a microwave (2.45 GHz) using a bias ECR plasma CVD method or a bias ECR plasma CVD method.
+ NH ₃ mixed gas or SiH ₂ Cl ₂ + NH ₃ mixed gas and Ar or N ₂ as a buffer gas were used to form a film.

[0072] In Example 18 This example, a Si _x N _y film shown in Examples 15, except that was formed by the following method, in the same manner as in Example 17, to form an antireflective film. That is, in this embodiment,
Parallel plate plasma CVD, ECR plasma CVD
Using a mixed gas of SiH ₄ + NH ₃ or SiH ₂ Cl using the bias ECR plasma CVD method.
_A film was formed using a ₂ + NH ₃ mixed gas.

[0073] In Example 19 In this example, the Si _x N _y film shown in Examples 15, except that was formed by the following method, in the same manner as in Example 15, to form an antireflective film. That is, in this embodiment,
Parallel plate plasma CVD, ECR plasma CVD
Using a mixed gas of SiH ₄ + NH ₃ or SiH ₂ Cl using the bias ECR plasma CVD method.
_A film was formed using a ₂ + NH ₃ mixed gas and Ar or N ₂ as a buffer gas. Incidentally, after forming the _Si x _{N y} film was subjected to plasma treatment with _{O 2.}

[0074] In Example 20 In this example, an antireflection film made of Si _x N _y film, by the following procedure, except that etching the resist pattern as a mask, in the same manner as in Example 15, the underlying substrate processed. That is, in the present embodiment, _Si x _{N y}
Etching of the _{membrane, C 4 F 8 (30~70SCCM)} +
Using CHF ₃ (10-30 SCCM) gas system, 2P
Under a pressure of about a, a desired pattern was etched by a reactive etching method in which a power of about 100 to 1000 W was applied to increase ionicity.

[0075] In Example 21 In this example, an antireflection film made of Si _x N _y film, by the following procedure, except that etching the resist pattern as a mask, in the same manner as in Example 15, the underlying substrate processed. That is, in the present embodiment, _Si x _{N y}
The etching of the film is performed using a gas system of S ₂ F ₂ (5 to 30 SCCM) under a pressure of about 2 Pa and 100 to 1000.
A desired pattern was etched by a reactive etching method in which ionicity was increased by applying a power of about W.

Embodiment 22 In this embodiment, a mixed gas of SiH ₄ and N ₂ O is used
i _x N _y film was formed, the formed film was confirmed that hydrogen is contained. That is, in the above embodiment, a portion of the _Si x _{N y} film and thought have antireflection _film, Si _x N y _{H z} films (where, z is 0 Any Good) is considered to have been. The presence of such hydrogen
Although the degree is unknown, it is thought that it contributes to the antireflection function to some extent. When hydrogen-containing gas is used as a source gas, hydrogen is generally considered to be contained in the film in some form.
Hydrogen is remarkable in plasma-based film forming means such as a plasma method.

Next, on a base substrate made of W-Si ,
And Si _x N _y H _z forming an antireflection film made of the film, showing the results of examining the standing wave effect of the photoresist. Specifically, at the exposure wavelength of KrF, n = 1.93, k =
On an underlying substrate made of 2.73 of _W-Si, Si x N
The anti-reflection film made of _{y H z, n = 2.12,} k = 0.
The thickness is 29 n by the plasma CVD method so as to approach 54.
m, a silicon oxide film with n = 1.52 and k = 0 with a thickness of 170 nm is formed thereon, and n =
A photoresist having a film thickness of 1.80 and k = 0.011 was formed.

A simulation result of the standing wave effect in that case is shown by with ARL in FIG. For comparison, the result of similarly obtaining the standing wave effect except that the antireflection film was not provided is shown in FIG.
Indicated by ARL. According to this example, it was confirmed that the standing wave effect could be almost completely eliminated. In fact, K
Using the exposure wavelength of rF, the photoresist was subjected to photolithography processing on the undersubstrate made of W-Si using the antireflection film under the above conditions using the 0.35 μm rule. As a result, a good fine pattern was formed. Was.

Embodiment 23 As shown in FIG. 44, on an underlying substrate G made of W-Si , at an exposure wavelength of KrF, n = 1.52 and k = 0.
A silicon oxide film Ox of a thickness of 170 nm,
_Thereon, an antireflection film made of _{Si x N y H 2, n} =
2.1, a film is formed to a thickness of 29 nm by a plasma CVD method so that k = 0.6, and n = 1.80,
A photoresist with k = 0.011 was formed.

The simulation result of the standing wave effect in this case is equivalent to the with ARL in FIG. 43, and is compared with the result obtained in the same manner except that the antireflection film is not provided. It was confirmed that the standing wave effect could be almost completely eliminated. Actually, using the exposure wavelength of KrF, the photolithography process of the photoresist was performed on the undersubstrate made of W-Si using the antireflection film under the above conditions using the 0.35 μm rule. Was formed.

[0081] On the underlying substrate consisting of Example 24 W-Si, at the exposure wavelength of _i-line, an antireflection film made of _{Si x N y H z, n} = 1.
A film is formed with a thickness d = 25 ± 10 nm by a plasma CVD method so as to have a thickness of 8 to 3.0 and k = 0.5 to 0.9, and a film is formed thereon before exposure (transmittance 10% / umt). n = 1.7,
k = 0.06, n = after exposure (transmittance 95% / ut)
A photoresist having a thickness of 1.7 and k = 0.0015 was formed.

The simulation result of the standing wave effect in this case is equivalent to the with ARL in FIG. 43, and is compared with the result obtained in the same manner except that the antireflection film is not provided. It was confirmed that the standing wave effect could be almost completely eliminated. Actually, a photolithography process of a photoresist was performed on an underlying substrate made of W-Si using an antireflection film under the above conditions using an exposure wavelength of i-line and a 0.35 μm rule. A pattern was formed.

[0083] on the base substrate made from Example 25 monocrystalline silicon, in KrF exposure _wavelength, the antireflection film made of Si _x N y _{H z,}
Plasma CV so as to approach n = 2.0 and k = 0.55
A film is formed with a film thickness d = 32 nm by the method D, and n =
A photoresist having a film thickness of 1.80 and k = 0.011 was formed. In this _case, Si _x N y optimum optical constants and thickness of the antireflection film consisting of _{H z} is, n = 1.9, k = 0.3
5, d = 100 nm.

The simulation result of the standing wave effect in these cases is equivalent to withARL in FIG.
Except that the anti-reflection film was not provided, it was confirmed that the standing wave effect could be almost completely eliminated as compared with the result obtained in the same manner. Actually, using an exposure wavelength of KrF, on an undersubstrate made of single crystal silicon,
As a result of performing photolithography processing on the photoresist using the antireflection film under the above conditions and using the 0.35 μm rule, a favorable fine pattern was formed.

[0085] After forming the antireflection film made from Example 26 _Si x _N y _{H z} films, except that the surface was _{O 2} plasma treatment, in Example 2
Photolithography processing of the photoresist was performed in the same manner as in 3, 24, or 25 according to the 0.35 μm rule. As a result, a favorable fine pattern could be formed.
By performing the O ₂ plasma treatment, acid deactivation under the chemically amplified resist can be prevented, and footing or overhang of the pattern edge portion of the resist can be prevented.

[0086] On the underlying substrate consisting of Example 27 Al-Si, the KrF exposure _wavelength, the antireflection film made of _{Si x N y H z, n} =
2.09, plasma CVD so as to approach k = 0.87
The film was formed to a thickness of 24 nm by the method, and n = 1.8 was further formed thereon.
A photoresist having 0 and k = 0.011 was formed. The simulation result of the standing wave effect in that case is shown as with ARL in FIG. Also, for comparison,
The result of obtaining the standing wave effect in the same manner except that the anti-reflection film is not provided is shown as "without ARL" in FIG. According to this example, it was confirmed that the standing wave effect could be almost completely eliminated. Actually, using a KrF exposure wavelength, a photoresist was subjected to photolithography processing on a base substrate made of Al-Si using an antireflection film under the above-mentioned conditions according to the 0.35 μm rule. Was formed.

Example 28 At the exposure wavelength of the i-line, n = 3.067 and k = 2.7.
On the base substrate made of a 93 _{W-Si, Si x N y} H
_The anti-reflection film made of _z is formed by n = 2.58 and k = 0.42.
Was formed to a thickness of 30 nm by a plasma CVD method so as to approach, and a naphthokimenediazide-based photoresist having n = 1.693 and k = 0.032 was formed thereon. 0.44 μm of the photoresist using i-line
Exposure was performed to obtain an m-line and space (L / S) pattern, and the antireflection effect was measured. Fig. 4 shows the results.
6 is indicated by with ARL. For comparison,
Except that the anti-reflection film was not used, the result of measuring the anti-reflection effect in the same manner as in FIG.
L. From this figure, the effect of the antireflection film in this embodiment can be understood. Similarly, simulation results are shown in FIG. 47 (graph on W-Si , i-line, absorptivity) and FIG. 48 (graph on W-Si , i-line, reflectivity). As shown in these figures, in this embodiment, an excellent antireflection effect can be obtained in both cases of the reflectance and the absorptance.

FIGS. 49 and 50 show the relationship between the resist thickness and the critical dimension. In each case, experiments were performed on W-Si using KrF excimer laser light. FIG. 49 shows the case of a 0.30 μm line and space pattern, and FIG.
This is the case of a 5 μm line and space pattern. In each case, a chemically amplified positive resist was used as the resist.

Embodiment 29 As described above, as an antireflection film for excimer laser light, for example, on a high-melting-point metal silicide, a material having n of about 2.4 and k of about 0.7 is suitable. Si _x N _y film, or _Si x _N y _{H z} film is effective as an anti-reflection film. Further, n and k having these antireflection effects are provided.
To form a _Si x _{N y} film, or _Si x _N y _{H z} film having, by changing the composition ratio of these films (x, y), would be able to change the n and k of the film But,
It is not always easy to form a film having these desired n and k by controlling the composition ratio with good controllability.

In this embodiment, the desired n as the antireflection film
In order to form a film having と and k, an antireflection film is formed by using a material containing at least a Si element and a material containing at least an N element as source gases. In this embodiment, at least the substance containing Si is SiH
₄ , a film having a desired anti-reflection effect is formed by using NH ₃ as a substance containing at least N and controlling the optical constant of the film using a gas flow ratio of SiH ₄ and NH ₃ as a parameter. did. The optical constants of the films when the gas flow ratios of SiH ₄ and N ₂ O are changed using a parallel plate plasma CVD apparatus have a corresponding relationship. Here, the method of controlling the optical constant of the film mainly with the gas flow ratio as a parameter has been described.
The optical constant of the film can be controlled by using power and substrate temperature as parameters.

[0091]

As described above, according to the method for forming a resist pattern according to the present invention, when a resist pattern is formed on an arbitrary base substrate using light of an arbitrary single wavelength as an exposure light source, The standing wave effect at the time of exposure can be minimized, and a favorable and stable resist pattern can be formed even if the resist pattern is fine.
Further, according to the antireflection film forming method according to the present invention, an antireflection film having an optical condition that minimizes the standing wave effect,
The film can be formed very easily, and its etching is also easy.

[Brief description of the drawings]

FIG. 1 is a view for explaining a problem of a conventional technique, and is a view showing light interference in a resist film.

FIG. 2 is a diagram illustrating a problem of the related art, and is a diagram illustrating a standing wave effect.

FIG. 3 is a diagram for explaining a problem of the related art, and is a diagram illustrating a standing wave effect.

FIG. 4 is a diagram for explaining a problem of the related art, and is a diagram illustrating a standing wave effect.

FIG. 5 is a diagram for explaining a problem of the related art, and is a diagram showing an influence of a step.

FIG. 6 is a diagram showing the effect of the standing wave effect.

FIG. 7 is a diagram showing the effect of the standing wave effect.

FIG. 8 is a diagram showing the effect of the standing wave effect.

FIG. 9 is a diagram illustrating a relationship between a variation in the amount of absorbed light and a variation in pattern dimension.

FIG. 10 is a diagram illustrating a standing wave effect.

FIG. 11 shows an anti-reflection film AR for a certain resist film thickness.
FIG. 9 is a diagram illustrating a locus of a change in the amount of absorbed light of the resist film (a contour line of the amount of absorbed light) when the thickness of L is fixed and n _arl and k _arl are changed.

FIG. 12 is a diagram showing trajectories (contour lines) for other different resist film thicknesses.

FIG. 13 is a diagram showing trajectories (contour lines) for other different resist film thicknesses.

FIG. 14 is a diagram showing trajectories (contour lines) for other different resist film thicknesses.

FIG. 15 is a diagram showing a standing wave effect to be solved.

FIG. 16 is a diagram showing a locus (contour line of the amount of absorbed light) of a change in the amount of absorbed light of the resist film with respect to a change in n _ar and k _aar for a resist film thickness of 985 nm when the thickness of the anti-reflection film is 30 nm.

FIG. 17 is a diagram showing a locus (contour line) for a resist film thickness of 1000 nm.

FIG. 18 is a diagram showing a locus (contour line) for a resist film thickness of 1017.5 nm.

FIG. 19 is a diagram showing a locus (contour line) for a resist film thickness of 1035 nm.

FIG. 20 is a diagram showing a standing wave effect under optimal conditions (Example).

FIG. 21 is a diagram showing a standing wave effect under optimal conditions (Example).

FIG. 22 is a diagram showing the relationship between the thickness of an antireflection film and n as an optical condition.

FIG. 23 is a view showing the relationship between the thickness of an antireflection film and k as an optical condition.

24 is a diagram showing the behavior of the _Si x _{N y} deposited by CVD.

FIG. 25 is a cross-sectional view showing a film formation structure of an antireflection film according to another example.

26 is a diagram illustrating an anti-reflection effect of _Si on _{W-Si x N y (25nm} ).

FIG. 27 is a cross-sectional view illustrating a film formation structure of an antireflection film according to another example.

FIG. 28 is a diagram showing a locus (a contour line of the amount of absorbed light) of a change in the amount of absorbed light of the resist film with respect to a change in n _ar and k _aar for a resist film thickness of 982 nm when the thickness of the anti-reflection film is 30 nm.

FIG. 29 is a diagram showing loci (contour lines) for a resist film thickness of 1000 nm.

FIG. 30 is a diagram showing a locus (contour line) for a resist film thickness of 1018 nm.

FIG. 31 is a diagram showing a locus (contour line) for a resist film thickness of 1035 nm.

FIG. 32 is a diagram showing a standing wave effect under optimal conditions.

FIG. 33 is a diagram showing a standing wave effect under optimal conditions.

FIG. 34 is a diagram showing the relationship between the thickness of an antireflection film and k as an optical condition.

FIG. 35 is a diagram illustrating optical constant characteristics depending on film forming conditions of a Si _x N _y film.

FIG. 36 is a diagram showing a standing wave effect under optimum conditions in another embodiment.

FIG. 37 is a cross-sectional view showing a film formation structure of an antireflection film in another example.

FIG. 38 is a diagram showing a standing wave effect.

39 is a diagram illustrating an anti-reflection effect of the _Si x _{N y} film on Si (32 nm).

40 is a diagram illustrating an anti-reflection effect of the _Si x _{N y} film on Si (100 nm).

[Figure 41] _Si x _{N y} film on the polysilicon (33 nm)
It is a figure which shows the reflection prevention effect of.

FIG. 42 is a diagram showing a change in characteristics of an optical constant depending on film forming conditions of a Si _x N _y film.

FIG. 43 is a diagram showing an antireflection effect in the example.

FIG. 44 is a view showing a film formation structure of an antireflection film in another example.

FIG. 45 is a diagram showing an antireflection effect in another embodiment.

FIG. 46 is a diagram showing an antireflection effect in another embodiment.

FIG. 47 is a diagram showing a simulation result (related to an absorptivity) of an antireflection effect in the embodiment shown in FIG. 46;

FIG. 48 is a diagram showing a simulation result (related to a reflectance) of an antireflection effect in the embodiment shown in FIG. 46;

FIG. 49 is an operation explanatory view of another example (0.30 μmL / S).

FIG. 50 is an operation explanatory view of another example (0.35 μmL / S).

[Explanation of symbols]

 ARL Anti-reflection coating PR photoresist S Base substrate

 ──────────────────────────────────────────────────続 き Continued on the front page (31) Priority claim number Japanese Patent Application No. 4-87912 (32) Priority date Hei 4 (1992) March 11 (33) Priority claim country Japan (JP) (31) Priority Claim number Japanese Patent Application No. 4-244314 (32) Priority Date Hei 4 (1992) August 20 (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 4-316073 (32) Priority Japan, JP (JP) (56) Reference JP-A-60-153125 (JP, A) JP-A-59-5640 (JP, A) JP JP-A-51-58072 (JP, A) JP-A-1-241125 (JP, A) JP-A-2-148731, (JP, A)

Claims (37)

(57) [Claims] 1. A semiconductor device having a multilayer structure, comprising :
Nitrogen formed directly or through another layer on the ground substrate
Photoresist on the anti-reflection film
Exposing the resist with a single wavelength to form a resist pattern
A method for forming a resist pattern, comprising: forming an antireflection film comprising the silicon nitride-based film,
Depending on the type of underlying substrate, the photoresist
Standing due to fluctuation of resist film or resist film thickness
The above conditions under which the variation of the wave effect is minimized
The reflection refractive index n, absorption refractive index k, and film thickness of the
To form a film while adjusting the film forming conditions
That, the resist pattern forming method. 2. The undersubstrate has a surface formed of a high melting point metal or
2. The method for forming a resist pattern according to claim 1, wherein the method is formed of a refractory metal silicide-based material . 3. The high melting point metal is tungsten.
The refractory metal silicide-based material is tungsten silicide.
3. The method for forming a resist pattern according to claim 2, wherein the resist pattern is an oxide . 4. The undersubstrate has a surface having a low melting point metal-based material.
The method for forming a resist pattern according to claim 1, wherein: 5. The low-melting point metal-based material is aluminum,
Aluminum-silicon alloy, aluminum-silicon
5. The method for forming a resist pattern according to claim 4, wherein the resist pattern is one of a copper alloy, copper, and a copper alloy . 6. The surface of the undersubstrate is made of a silicon-based material.
2. The method according to claim 1, wherein the resist pattern is formed. 7. The silicon-based material is a single crystal silicon,
Polycrystalline silicon, amorphous silicon, doped polysilico
7. The method for forming a resist pattern according to claim 6, wherein the method is one selected from the group consisting of : 8. The method according to claim 8, wherein the surface of said base substrate is made of a high melting point metal or a high melting point metal.
In the case of a metal silicide-based material having a melting point, the antireflection film has an exposure wavelength of 150 to 450 nm.
And the reflection refractive index n is 1.0 or more and 3.6 or less,
The collection index k is 0.11 or more and 0.75 or less, and the film thickness is
Composed of a silicon nitride film with a thickness of 10 nm or more and 100 nm or less.
2. The method for forming a resist pattern according to claim 1 , wherein the anti-reflection film is formed. 9. The high melting point metal is tungsten.
The refractory metal silicide-based material is tungsten silicide.
The method for forming a resist pattern according to claim 8, wherein the resist pattern is an id . 10. The surface of the undersubstrate is made of a high melting point metal or
In the case of a refractory metal silicide-based material, the antireflection film has an exposure wavelength of 150 to 450 nm.
And the reflection refractive index n is 1.7 or more and 5.9 or less,
The collection index k is a positive number of 0.51 or less, and the film thickness is 25 n
m and not more than 100 nm.
2. The method for forming a resist pattern according to claim 1 , which is an anti-reflection film . 11. The refractory metal is tungsten,
The refractory metal silicide-based material is tungsten silicide.
The method for forming a resist pattern according to claim 10 , wherein the side is a side . 12. The method according to claim 12, wherein the surface of the undersubstrate has a low melting point metal material.
In the above case, the antireflection film has an exposure wavelength of 150 to 450 nm.
The refractive index n is 1.3 or more and 3.6 or less,
The collection index k is 0.2 or more and 1.5 or less, and the film thickness is 10
composed of a silicon nitride film having a thickness of not less than 70 nm and not more than 70 nm.
2. The method for forming a resist pattern according to claim 1 , which is an anti-reflection film . 13. The low melting point metal-based material is aluminum
Aluminum, silicon-alloy, aluminum-silicon
13. The method for forming a resist pattern according to claim 12, wherein the method is any one of a con-copper alloy, copper, and a copper alloy . 14. A base material having a low melting point metal material.
In the above case, the antireflection film has an exposure wavelength of 150 to 450 nm.
And the reflection refractive index n is 1.9 or more and 5.9 or less,
The collection index k is 0.2 or more and 0.75 or less, and the film thickness is 2
5 to 90 nm silicon nitride film
2. The method for forming a resist pattern according to claim 1, wherein said method is an anti-reflection film . 15. The method according to claim 15, wherein the low melting point metal-based material is aluminum.
Aluminum, silicon-alloy, aluminum-silicon
The method for forming a resist pattern according to claim 14, wherein the method is one of a con-copper alloy, copper, and a copper alloy . 16. The method according to claim 16, wherein the surface of the base substrate is made of a silicon-based material.
In some cases, the antireflection film has an exposure wavelength of 150 to 450 nm.
And the reflection refractive index n is 1.8 or more and 2.6 or less,
Yield refractive index k is 0.1 to 0.8, the film thickness is 20
composed of a silicon nitride film having a thickness of not less than 150 nm and not more than 150 nm.
2. The method for forming a resist pattern according to claim 1, wherein said method is an anti-reflection film . 17. The silicon-based material is a single-crystal silicon.
, Polycrystalline silicon, amorphous silicon, doped policy
17. The method of forming a resist pattern according to claim 16, wherein the method is one selected from the group consisting of silicon . 18. A high melting point metal or a high melting point metal
Directly or on the underlying substrate made of a side material
An anti-reflection film provided with a layer having an exposure wavelength of 150 to 450 nm.
The refractive index n is 1.0 or more and 3.6 or less,
The ratio k is 0.11 or more and 0.75 or less, and the film thickness is 10 nm or more.
100 nm or less, due to fluctuations in the thickness of the resist film
Silicon nitride that minimizes the dispersion of the standing wave effect
An anti-reflective coating composed of a corn-based coating . 19. The refractory metal is tungsten,
The refractory metal silicide-based material is tungsten silicide.
The antireflection film according to claim 18 , which is a side . 20. A high melting point metal or high melting point metal
Directly or on the underlying substrate made of a side material
An anti-reflection film provided with a layer having an exposure wavelength of 150 to 450 nm.
And the refractive index n is 1.7 or more and 5.9 or less,
The ratio k is a positive number of 0.51 or less, and the film thickness is 25 nm or more.
100 nm or less, due to fluctuations in the thickness of the resist film
Silicon nitride that minimizes the dispersion of the standing wave effect
An anti-reflective coating composed of a corn-based coating . 21. The refractory metal is tungsten,
The refractory metal silicide-based material is tungsten silicide.
The antireflection film according to claim 20 , which is a side . 22. A base material whose surface is made of a low melting point metal-based material.
Reflection provided directly or through other layers on the plate
An anti- reflection film , wherein the anti-reflection film has an exposure wavelength of 150 to 450 nm.
The refractive index n is 1.3 or more and 3.6 or less,
The ratio k is 0.2 or more and 1.5 or less, and the film thickness is 10 nm or more and 70.
nm or less, and a standing wave due to fluctuations in the thickness of the resist film
Silicon nitride based with minimum effect variation
An anti-reflection film composed of a film. 23. The low-melting point metal-based material is aluminum
Aluminum, silicon-alloy, aluminum-silicon
The anti-reflection film according to claim 22, wherein the anti-reflection film is any one of a con-copper alloy, copper, and a copper alloy . 24. A base material whose surface is made of a low-melting metal material.
Reflection provided directly or through other layers on the plate
An anti- reflection film , wherein the anti-reflection film has an exposure wavelength of 150 to 450 nm.
The refractive index n is 1.9 or more and 5.9 or less,
The ratio k is a positive number between 0.2 and 0.75, and the film thickness is 2
5 nm or more and 90 nm or less, the change in the thickness of the resist film.
The dispersion of the standing wave effect due to motion
An antireflection film made of a silicon nitride-based film. 25. The low-melting point metal-based material is aluminum
Aluminum, silicon-alloy, aluminum-silicon
The antireflection film according to claim 24, wherein the antireflection film is any one of a con-copper alloy, copper, and a copper alloy . 26. An undersubstrate whose surface is made of a silicon-based material
Anti-reflective coating, directly or through other layers
An anti-reflection coating , wherein the anti-reflection coating has an exposure wavelength of 150 to 450 nm.
The refractive index n is 1.8 or more and 2.6 or less,
Rate k is 0.1 or more and 0.8 or less, and film thickness is 20 nm or more and 15
0 nm or less, standing due to variation in the thickness of the resist film
Silicon nitride with minimum dispersion of wave effect
An anti-reflection film composed of a system film . 27. The silicon-based material is a single crystal silicon
, Polycrystalline silicon, amorphous silicon, doped policy
27. The anti-reflection film according to claim 26, wherein the anti-reflection film is a kind selected from the group consisting of recons . 28. A semiconductor device comprising a plurality of layers, at least a surface of which has a high melting point metal or a high melting point metal silicide.
A base substrate made of a metal-based material , and exposed directly or through another layer on the base substrate.
When the light wavelength is 150 to 450 nm, the reflection refractive index n is
1.0 or more and 3.6 or less, absorption refractive index k is 0.11 or more
0.75 or less, and the film thickness is 10 nm or more and 100 nm or less.
Of the standing wave effect due to fluctuations in the resist film thickness
Is made of a silicon nitride-based film that minimizes
A semiconductor device having an anti-reflection film . 29. The refractory metal is tungsten,
The refractory metal silicide-based material is tungsten silicide.
29. The semiconductor device according to claim 28 , which is a side . 30. A semiconductor device comprising a plurality of layers, at least a surface of which has a high melting point metal or a high melting point metal silicide.
A base substrate made of a metal-based material , and exposed directly or through another layer on the base substrate.
When the light wavelength is 150 to 450 nm, the reflection refractive index n is
1.7 or more and 5.9 or less, and the absorption refractive index k is 0.51 or less
It is a positive number and the film thickness is 25 nm or more and 100 nm or less.
Of the standing wave effect due to fluctuations in the resist film thickness
Is made of a silicon nitride-based film that minimizes
A semiconductor device having an anti-reflection film . 31. The refractory metal is tungsten,
The refractory metal silicide-based material is tungsten silicide.
31. The semiconductor device according to claim 30 , which is a side . 32. A semiconductor device comprising a plurality of layers, wherein at least a surface of the substrate comprises a low melting point metal-based material.
On the underlying substrate, directly or through another layer,
When the wavelength is 150 to 450 nm, the reflection refractive index n is
1.3 or more and 3.6 or less, and the absorption refractive index k is 0.2 or more.
5 or less, the film thickness is 10 nm or more and 70 nm or less,
Minimal variation in standing wave effect due to variation in film thickness
Of a silicon nitride based film with a value of
A semiconductor device having an anti-reflection film . 33. The low-melting point metal-based material is aluminum
Aluminum, silicon-alloy, aluminum-silicon
33. The semiconductor device according to claim 32, wherein the semiconductor device is one of a con-copper alloy, copper, and a copper alloy . 34. In a semiconductor device comprising a plurality of layers, an undersubstrate having a surface made of a low melting point metal-based material and said undersubstrate
On top, directly or through another layer, the exposure wavelength is 15
The reflection refractive index n is 1.9 or more at 0 to 450 nm.
5.9 or less, and the absorption refractive index k is 0.2 or more and 0.75 or less
A positive number, a film thickness of 25 nm or more and 90 nm or less,
Variations in the standing wave effect due to variations in the resist film thickness
It is composed of a silicon nitride-based film with the minimum value.
A semiconductor device having an anti-reflection film . 35. The low melting point metal-based material is aluminum
Aluminum, silicon-alloy, aluminum-silicon
35. The semiconductor device according to claim 34, wherein the semiconductor device is one of a con-copper alloy, copper, and a copper alloy . 36. A semiconductor device comprising a plurality of layers, comprising : a base substrate having a surface made of a silicon-based material ;
When the wavelength is 150 to 450 nm, the reflection refractive index n is
1.8 or more and 2.6 or less, and the absorption refractive index k is 0.1 or more and 0.2 or less.
8 or less, the film thickness is 20 nm or more and 150 nm or less, and
The variation of the standing wave effect due to the variation of the
It is composed of a silicon nitride based film with a small value
A semiconductor device having an antireflection film . 37. The silicon-based material is a single-crystal silicon.
, Polycrystalline silicon, amorphous silicon, doped policy
37. The semiconductor device according to claim 36 , which is one kind selected from the group consisting of a recon .