JP3339156B2 - Method for manufacturing fine pattern and method for manufacturing 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 manufacturing a fine pattern and a method for manufacturing a semiconductor device using the method.

[0002]

2. Description of the Related Art Currently, in the research and development of semiconductor integrated circuits, design rule devices in the sub-half micron range are being researched and developed. In photolithography technology used in the development of these devices, an exposure apparatus using a single wavelength light as an exposure light source called a stepper (reduction projection exposure machine) is used.

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 multiple interference of exposure light occurs in the resist film. That is, as shown in FIG. 1, the incident light P and the reflected light R from the interface between the resist PR and the substrate S cause interference in the resist film. 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 on the resist surface, absorption by the substrate, light emitted from the resist, and the like. Show. The amount of absorbed light is the energy that causes the resist to undergo a photoreaction.

FIG. 2 shows a result of 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 the exposure light, KrF of λ = 248 nm was assumed. Further, the degree of change in the amount of absorbed light differs depending on the type of the underlying substrate, as can be understood from a comparison between FIG. 3 and FIG. Figures 2, 3, 4
, XP8843 (Shipley Co.) was used for the resist, but the underlying layers were Si and Al-S, respectively.
i, W-Si. That is, the degree of change in the amount of absorbed light is determined by the complex amplitude reflectance (R) in consideration of multiple interference determined by the optical constant (n, k) of the base (substrate) and the optical constant (n, k) of the resist film ( (R) indicates a vector quantity having a real part and an imaginary part).

Further, in an actual device, as shown in FIG. 5, irregularities always exist on the substrate surface. For example,
There is a protrusion In such as polysilicon. For this reason, when the resist film RP 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 protrusion In is smaller than the resist film thickness d _{PR1 in the} other portions.

As described above, the standing wave effect varies depending on the resist film thickness. Therefore, the change in the amount of light absorbed by the resist due to the effect of the standing wave effect also varies. Come. 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 using a stepper with the same wavelength and the same numerical aperture.
This phenomenon is common to all types of resist.

The dimensional accuracy of a resist pattern in a photolithography process at the time of manufacturing a semiconductor device is generally ± 5%. In order to achieve the dimensional accuracy of ± 5%, it is essential to reduce the standing wave effect. FIG. 6 shows a dimensional change of the resist pattern (vertical axis) with respect to a change in the amount of absorbed light in the resist film (horizontal axis). As is clear from FIG. 6, for example, when fabricating a device having a rule of 0.35 μm, the variation in the amount of light absorbed by the resist film is in the range of 6%.
It is required that:

[0008]

In order to meet the above-mentioned demands, anti-reflection techniques are being actively studied in various fields. As a result, high melting point metal silicide (for example, W-Si), metal (for example, A1-Si), silicon-based material (for example, Po
As excellent anti-reflective materials on ly-Si), SiC,
_{SiO x, Si x O y N} z, Si x N y is, by the present inventors, have been found.

[0009] In actual device during manufacturing, transferring a semiconductor mask pattern on the resist, and the transferred resist as a _{mask, SiC, SiO x, Si x} O y N z,
Si _x N _y such as an antireflection film, and a refractory metal silicide (e.g. W-Si), a metal (e.g., A1-Si), silicon-based material (e.g., Poly-Si), by etching, fabricating a semiconductor substrate I will do it. At that time, if a selective ratio cannot be obtained between the resist and the layer to be processed at the time of etching, dimensional controllability deteriorates.

For this reason, in the etching of the metal layer where the selectivity is particularly problematic, the thickness of the resist is increased, or the anti-reflection film on the layer to be processed is further provided with a plasma-teos (P-TEOS) or the like. An oxide-based inorganic film is formed, the pattern is transferred to the oxide film using the transferred resist as a mask, the resist is removed, and the metal layer is etched using the transferred oxide film as a mask. That is, a so-called inorganic mask method is used.

However, when the thickness of the resist is increased, there is a problem that the resolution performance is deteriorated.
The inorganic mask method using such methods cannot be used as a mass production technique for semiconductor devices due to the complexity of the process. Therefore, when a semiconductor mask pattern is formed on an undersubstrate, particularly a wiring material, on which a large selectivity cannot be obtained between a resist and a layer to be processed at the time of etching, some measure is urgently indispensable.

The present invention has been made in view of the above circumstances, and determines an inorganic film having both an anti-reflection effect and an inorganic mask so that a mask pattern can be favorably formed without increasing the number of steps. It is an object of the present invention to provide a method for manufacturing a fine pattern and a method for manufacturing a semiconductor device, which can transfer a good mask pattern.

[0013]

In order to achieve the above object, a method for manufacturing a fine pattern according to the present invention comprises the steps of: forming an antireflection film made of an inorganic film on a base substrate; A step of forming a resist film on the antireflection film, a step of exposing the resist film using i-line or light having a wavelength shorter than the i-line, and transferring a mask pattern to the resist film; Etching the anti-reflection film using the resist film to which the mask pattern has been transferred as a mask, and transferring the mask pattern to the anti-reflection film; and using the anti-reflection film to which the mask pattern has been transferred as a mask. Etching the substrate and transferring the mask pattern to the underlying substrate.

[0014] As the anti-reflection film, in the present _{invention, Si x O y N z:} H film is used. Si _x O _y N _z:
The H film, an Si _x O _y N _z film containing hydrogen H.
The antireflection film has a refractive index (n) of 1.7 or more.
4 or less, the extinction coefficient (k) is 0.85 or less, a film thickness of Ru 100~500nm der.

The surface of the undersubstrate is formed of a conductive layer such as a wiring layer or a gate electrode. When the surface of the base substrate is formed of a conductive layer such as a wiring layer or a gate electrode, it is preferable to use a chlorine-based gas at the time of etching. The resist film is preferably removed when the underlying substrate is etched using the antireflection film as a mask. This is because if the underlying substrate is processed with the resist film attached, carbon C contained in the resist film may adversely affect the underlying substrate processing during etching.

The method for producing a fine pattern according to the present invention comprises:
It can be preferably used in a manufacturing process of a semiconductor device.
The present invention relates to an inorganic material having both an anti-reflection effect and an inorganic mask when a semiconductor device is manufactured using i-line (365 nm) or light having a shorter wavelength, for example, i-line, KrF, or ArF excimer laser as a light source. By forming the film on the metal layer, a good and stable mask pattern can be formed without increasing the number of steps.

The following means was used to determine an inorganic film having both an antireflection effect and an inorganic mask. (I) For a resist film of a certain thickness that is arbitrarily determined,
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 inside the resist at the thickness of each resist film obtained in the above (I), a common area where the difference in the amount of absorbed light is minimized is found and limited by this common area. Optical conditions, (I)
The optical conditions (n, k) for the film thickness of the antireflection film determined in the above.

(III) By changing the thickness of the antireflection film,
By repeating the above operations (I) and (II), the optical constants (n, k) of each optimum condition for each film thickness of the antireflection film are obtained. (IV) An anti-reflection film of an actual material having an optical constant of 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 lambda / 4n (see FIG. 7).

An anti-reflection film ARL is formed between the resist and the underlying substrate, and the film thickness d _arl and the optical constant are set to n.
_arl 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.
_When n _arl and k _arl are changed _{while arl} is fixed, the amount of light absorbed by the resist film at that point changes. When this changing trajectory, that is, the contour line of the absorbed light amount is obtained, FIG.
It becomes as shown in.

With respect to other different resist film thicknesses d _PR , at least at four positions at λ / 8n _PR intervals on the basis of at least the film thickness that maximizes or minimizes the standing wave effect.
9 to 11 corresponding to FIG. 8 are obtained (FIGS. 8 to 11 define the antireflection film thickness to be 20 nm and the resist film thicknesses to be 985 nm, 1000 nm, 1
018 nm and 1035 nm are shown). The above corresponds to the above means (I).

The common area of each of the graphs in FIGS. 8 to 11 shows an area 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-mentioned means (II).

Next, the above is repeated while the thickness d of the antireflection film is continuously changed. For example, assuming that the operation is performed with d = 20 nm up to the first step, the above is repeated while changing d. This allows
The conditions of the thickness d _{arl of the} antireflection film and the optical constants n _arl and k _arl that minimize the standing wave effect 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.

[0026] was examined for the above (I) by means of ~ (IV), an anti-reflection film which also serves as an inorganic film which can be suitably used in the process according to the present _{invention, Si X O y N z:} H film
There have been found to be particularly suitable. That is, a silicon-based film such as single-crystal silicon, polycrystalline silicon, amorphous silicon, or doped polysilicon, a high-melting-point metal silicide-based film such as dungsten or tungsten silicide, aluminum, aluminum silicon,
When a metal wiring film such as aluminum silicon kappa or aluminum kappa is formed, the antireflection film serving also as an inorganic film formed thereon has n = 1.7 to 2.4, k ≦
0.85 (preferably 0.1 ≦ k ≦ 0.6) the inorganic film has optical constants of a, in particular, Si _X O _y N _z: H film, 1
It turned out that it is preferable to use with a film thickness of 00 to 500 nm.

The reason for setting k to the above range is that when k exceeds 0.85, the thickness of the antireflection film can be reduced.
This is because the function as an inorganic film tends to decrease, and if k is too small, the film thickness tends to be too large in order to maintain the function as an antireflection film. This is derived from the following relational expression. That is, assuming that the wavelength is λ, the absorption coefficient of the film is α (= 4πk / λ), and the imaginary part of the refractive index of the film is k, the transmittance T of the film becomes
₀ , if the transmitted light is I, T (= I / I ₀ ) = exp
(−αd).

The absorption rate A of the film is expressed as follows: A = I ₀ -I = I
₀₋ I ₀ T = I ₀ × (1−T) That is, the absorbance A of the film increases as the transmittance T decreases, and the transmittance T decreases as the absorption coefficient α (= 4πk / λ) increases and the film thickness d increases.

[0029] These Si _X O _y N _z: H film, various CV
The film can be easily formed by the method D. For example, these films are 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 oxygen and nitrogen (for example, SiH ₄ + O ₂ + N
_The film can be formed using a mixed gas of ₂ ) or a mixed gas of a silane-based gas and a gas containing nitrogen (eg, SiH ₄ + N ₂ O). In this case, an argon Ar gas or the like can be used as a buffer gas.

For example, the Si _X O _y N _z : H film is shown in FIG.
As shown in FIGS. 2 (A) and 2 (B), the real part n of the refractive index is approximately 2.1 in a wavelength band of, for example, 248 nm, depending on the conditions at the time of film formation, particularly the flow rate ratio of the silane-based gas. The imaginary part k of the refractive index can be arbitrarily controlled by changing the flow ratio of the silane-based gas. Therefore, an antireflection film having an optical constant value required as an antireflection film for a specific base substrate can be easily formed.

For example, when a W-Si substrate is used as a base substrate, n = 2.12, k = 0.54, d = 2
A 9 nm anti-reflection coating is optimal and can minimize standing wave effects. When an A1-Si substrate is used as a base substrate, n = 2.09, k = 0.87,
An antireflection film with d = 24 nm is optimal and can minimize the standing wave effect. When a Si substrate is used as a base substrate, n = 2.0, k = 0.55, and d = 32.
An anti-reflection coating of nm is optimal and can minimize standing wave effects.

The Si _x O _y N _z of the conditions: H film,
As an inorganic film and an antireflection film, they were formed on tungsten silicide, aluminum silicon, and single crystal silicon, respectively. These are shown in FIGS.
As shown in FIGS. 13 to 15, Si _{x under} appropriate conditions
By using the O _y N _z : H film as the inorganic film and the anti-reflection film, the standing wave effect can be suppressed, and the anti-reflection effect can be achieved.

Further, the Si _X O _y N _z: H film, a resist as a _{mask, CF 4, CHF 3, 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.

[0034] _{Thus, Si X O y N z:} H film, it is possible to easily etched by fluorine-based gas similar to the oxide _{film, Si X O y N z:} H film thicker ( 1
(500 to 500 nm) and formed on the metal layer, the antireflection film and the inorganic mask can be simultaneously provided. _{Moreover, Si X O y N z:} H film, as compared to the silicon oxide film, etching rate during etching of the underlying substrate is from about 1/3 to configure the same functionality in the silicon oxide film as the inorganic film Film thickness is about 1 /
It can be 3.

According to the present invention, an anti-reflection effect can be obtained by forming a semiconductor mask pattern on a metal wiring having a step structure using i-line or light having a shorter wavelength, for example, i-line, KrF or ArF excimer laser. By forming an inorganic film and an anti-reflection film having both an inorganic mask function and an inorganic mask function on a base substrate, a good and stable mask pattern can be formed without increasing the number of steps.

[0036]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below. However, the present invention is not limited by the following examples, and can be variously modified within the scope of the present invention.

Embodiment 1 In this embodiment, a metal wiring having a stepped structure (conductive layer) is formed by using an i-line (365 nm) or light having a wavelength shorter than that, for example, i-line, KrF or ArF excimer laser. In the above semiconductor mask pattern formation, in order to form a good and stable mask pattern without increasing the number of steps, Si _x found by the present inventors as an inorganic film having both an antireflection effect and an inorganic mask.
This is an example in which an O _y N _z : H film is used on a metal layer.

The manufacturing method of this embodiment is similar to that shown in FIGS.
As shown in (D) and FIGS. 17 (E) and (F), for example, Al, Al-Si, Al-Si-Cu, Al-Cu
And the like can be suitably used in a semiconductor manufacturing process for forming a semiconductor mask pattern on a metal wiring material layer. However, the concept in this embodiment can be suitably applied irrespective of the type of the substrate, the type of the resist, and the type of the high reflection layer.

The embodiment shown in FIGS. 16 and 17 will be described in detail. In this embodiment, first, as shown in FIG. 16A, a gate electrode 8 having a polycide structure composed of a polysilicon layer 4 and a tungsten silicide 6 is formed on the surface of a semiconductor substrate 2 via a gate insulating layer. An interlayer insulating film 10 such as a silicon oxide film is formed thereon. The thickness of the interlayer insulating film 10 is not particularly limited, but is, for example, 300 to 600 nm, and preferably about 500 nm.

Next, fine pattern contact holes 12a and 12b are formed in the interlayer insulating film 10. The contact holes 12a and 12b of the fine pattern are formed by the method developed by the present inventor, but have no direct relation to the present invention, so that detailed description thereof will be omitted, but the method will be simplified. State.

That is, in the interlayer insulating film 10, a region located above the tungsten silicide 6 and a region located above the impurity diffusion layer formed on the surface of the semiconductor substrate 2 are exposed using a photomask. When doing it,
Base substrate (semiconductor substrate 2 on which polysilicon film 4, tungsten silicide film 6, and interlayer insulating film 10 are formed)
Are different in optical conditions. Conventionally, it has been difficult to form a fine pattern in a region having different optical conditions by a single exposure.

Therefore, first, a high absorption film is formed on the entire surface of the interlayer insulating film 10. As a high absorption film, n = 0.
A silicon-based material having a thickness of 9.5 to 40 nm, such as single crystal silicon, polycrystalline silicon, amorphous silicon, or doped silicon having 5 to 7 and k = 1.5 to 3.5 can be used. Further, a high melting point metal such as tungsten or titanium or a compound of a high melting point metal, in particular, a titanium-based material such as titanium nitride or titanium oxynitride can also be used. Such a refractory metal or a compound of a refractory metal has n = 0.5 to
It has an optical constant of 3.0, k = 0.5 to 3.0. The thickness of the high-absorption film made of the high-melting-point metal or the compound of the high-melting-point metal is preferably 15 to 120 nm. Further, a refractory metal silicide-based material such as tungsten silicide can be used. This refractory metal silicide-based material has n =
It has an optical constant of 0.5 to 4.5 and k = 1.5 to 3.5. Further, it is preferable that the thickness of the high absorption film composed of the high melting point metal silicide is 8 to 30 nm.

By forming such a high absorption film, the underlying substrate can be optically treated as a single substrate. Thereafter, a resist film is formed on the surface of the high absorption film via an antireflection film. Thereafter, if the resist film is patterned using a photomask, the standing wave effect can be minimized, and the resist film can be processed into a fine pattern with high precision. Thereafter, by etching the interlayer insulating film 10 with the resist film, the contact holes 12a and 12b having a fine pattern can be formed.

Next, in this embodiment, buried plug layers 14a and 14b of tungsten or the like are formed in the contact holes 12a and 12b by using a selective growth method or the like. Next, titanium nitride (Ti) is formed on the interlayer insulating layer 10 on which the buried plug layers 14a and 14b are formed.
N) or the like is formed. The underlayer 16 is formed, for example, by sputtering or CVD, and its thickness is not particularly limited, but is about 50 to 150 nm, preferably about 100 nm.

Next, a metal wiring layer 18 of Al, Al-Si, Al-Si-Cu, Al-Cu or the like as a conductive layer is formed on the underlayer 16. The metal wiring 18 is formed by, for example, a sputtering method or a CVD method and has a thickness of preferably about 300 to 500 nm, and more preferably about 400 nm.

The method of this embodiment is a method for processing the metal wiring layer 18 into a predetermined fine pattern, and the following method is employed. That is, as shown in FIG. 16 (A), on the metal wiring layer 18, as an anti-reflection film 20 which also serves as an inorganic film according to the present embodiment, it contains a Si _X O _y N _z film (hydrogen H; or less ,: also referred to as "Si _X O _y N _z H film") forming a. Although not particularly limited, the antireflection film 20 has a refractive index (n) of 1.7 or more and 2.4 or less and an extinction coefficient (k) of 0.85 or less. The thickness of the antireflection film is not particularly limited, but is preferably 1
It is from about 00 to 500 nm, and more preferably about 200 nm.

[0047] Si _X O _y N _z: H film, parallel plate type plasma CVD method, ECR plasma CVD method, or using a bias ECR plasma CVD method, a microwave, a silane gas and oxygen and nitrogen Mixed gas of a gas containing SiH ₄ + O ₂ + N ₂ or a gas containing a silane-based gas and nitrogen (eg, SiH ₄ + N ₂ )
_A film can be formed using a mixed gas of 2O).

[0048] The Si _x O _y N _z: H film, by controlling the gas flow rate ratio in forming, for example, as shown in FIG. 12 (A), (B) , in the wavelength band of wavelength 248nm The real part n of the refractive index has a constant value of about 2.1, and the imaginary part k of the refractive index can be arbitrarily controlled by changing the flow ratio of the gas containing silicon.

The optimum refractive index condition for the antireflection film 20 according to various film thicknesses is determined by the standing wave effect according to the optical condition of the underlying substrate as described in the section of the problem to be solved by the invention. Can be uniquely determined so as to minimize. To conditions of the base _{substrate, Si x O y N z:} H film,
By changing the flow ratio of the gas containing silicon, the imaginary part k of the refractive index can be controlled and adjusted to various types of base substrates.

For example, when the Al—Si metal wiring layer 18 is processed, the inorganic / anti-reflection film 20 formed thereon is formed of an optical film having n = 2.08 and k = 0.85. of thickness d = 25 nm with a constant Si _x O _y N _z:
An H film is used. On al-Si, as the inorganic film and the antireflection film, Si _x O _y N _z: antireflection effect of using H film (standing wave effect) shown in FIG. 18. As shown in FIG. 18, without providing the inorganic film and the anti-reflection film 20, Al-Si
As compared with the standing wave effect (curve A) when a resist film (XP8843) is directly formed on the upper surface, S = 25 nm in film thickness having optical constants of n = 2.08 and k = 0.85
i _x O _y N _z : A resist film (XP884)
The standing wave effect (curve B) when film 3) is formed is prevented as much as possible, and its variation can be suppressed to ± 0.48% or less. That is, n = 2.08 and k = 0.8
Of thickness d = 25 nm with a 5 optical constants Si _x O _y N
_z : An effective antireflection effect of the H film was confirmed.

The Si _x O used in the experiment shown in FIG.
_y N _z: H film was formed by CVD method using a SiH ₄ gas and N ₂ O gas, the flow ratio, SiH ₄ / N
₂ O was 0.83. Further, as the exposure light, K
rF was used. The n _PR and k _PR of the resist were 1.801 and 0.011, respectively. Also, Al-S
The n _sub and k _sub of the i-substrate were 0.089 and 2.354, respectively.

The same effect as the anti-reflection film can be obtained by reducing the imaginary part k of the refractive index which governs the absorption amount of the film, and increasing the film thickness accordingly. FIG. 19 shows that an inorganic film and an antireflection film of n = 2.04 and k = 0.225 are formed on an Al—Si substrate.
_x O _y N _z: H film was deposited at a film thickness of d = 205 nm,
The standing wave effect when a resist (XP8843) is applied on the film is shown by a curve B ′. A standing wave effect when a resist film is directly formed without providing an inorganic film and an antireflection film is shown by a curve A ′. As shown in the figure, by using the inorganic film and the antireflection film, the standing wave effect is almost completely canceled.

The Si _x O used in the experiment shown in FIG.
_y N _z: H film was formed by CVD method using a SiH ₄ gas and N ₂ O gas, the flow ratio, SiH ₄ / N
₂ O was 0.75. Further, as the exposure light, K
rF (wavelength λ = 248 nm) was used. Resist the n _PR
And k _PR were 1.801 and 0.011, respectively. Further, n _sub and k of the Al—Si substrate
_sub was 0.089 and 2.354, respectively.

Under the condition that the curves B and B ′ shown in FIG. 18 and FIG.
As shown in FIG. 1A, after a film is formed on the metal wiring layer 18, a resist film 24 is formed thereon. Resist film 2
The material 4 is not particularly limited. For example, XP8843 in which n _PR and k _PR are 1.802 and 0.0107, respectively, or another resist film is used. This resist film 24 is formed by, for example, a spin coating method. The thickness of the resist film 24 is not particularly limited, but is preferably 600 to 1200 nm, and more preferably about 1000 nm. As described above, since the inorganic film and the antireflection film 20 minimize the standing wave effect, even if a slight step is formed in the underlayer where the resist film 24 is formed, In addition, an error in a pattern dimension to be formed can be minimized.

Next, in this embodiment, in order to form a fine pattern on the resist film 24, an exposure process is performed by an exposure apparatus using an i-line or a short wavelength shorter than the i-line.
As shown in FIG. 16B, a fine pattern 26 is formed on the resist film 24. At this time, in this embodiment, the inorganic film / antireflection film 20 is formed on the metal wiring layer 18 to be processed, and the resist film 24 is formed thereon.
With the standing wave effect minimized, the resist film 24
Fine processing is possible. Therefore, the resist film 24
On the other hand, the fine pattern 26 with high precision can be formed favorably and stably.

[0056] Then, as a mask a resist film 24 is processed into a fine pattern 26, as shown in FIG. _{16 (C), Si x O} y N z: an inorganic film and an antireflection film 20 formed of H film Then, a predetermined fine pattern 28 is etched. When etching, CHF ₃ (50-1
Using a fluorine-based gas such as (00 SCCM) + O ₂ (30 SCCM), RIE (reactive ion etching) with enhanced ionicity is performed under a pressure of about 2 Pa and a power of about 100 to 1000 W.

Next, as shown in FIG. 16D, the resist film 24 is removed by oxygen plasma or the like. In the present invention, the resist film 24 may not necessarily be removed but may be subjected to an etching step in the next step. However, the removal of the resist film 24 provides better pattern processing by etching in the next step. Tends to be. Because, when processing the underlying substrate with the resist film attached,
During the etching process, carbon C contained in the resist film is
This is because there is a possibility that the processing of the underlying substrate may be adversely affected.

Next, in this embodiment, as shown in FIG. 17 (E), at least a chlorine-containing gas is used as a mask with the inorganic / anti-reflection film 20 having the fine pattern 28 formed thereon as a mask. The protection film 20, the metal wiring layer 18, and the underlayer 16 are simultaneously etched to form the metal wiring layer 18.
The semiconductor mask pattern is transferred to the underlayer 16 to form a fine pattern 30. Chlorinated Si _x for gas O _y N _z: etching rate of the H film (antireflection film 20) is approximately 300 nm, the etching rate of the metal wiring layer 18 is about 700 nm. Since the thickness of the metal wiring layer 18 is about 400 nm,
of nm order or more thick Si _x O _y N _z: By using the H film as the inorganic film and the antireflection film 20, metal wiring layers 1
To _{8, Si x O y N z} : by H film comprised an inorganic mask, is transferred semiconductor mask pattern can be satisfactorily formed by the fine pattern 30 stably. The antireflection film 20 as an inorganic film is removed at the same time when the fine pattern 30 is formed.

That is, the metal wiring layer 18 which is the layer to be processed
Si with a thickness of about half or more of _xO_yN_z: H film
By using the semiconductor mask pattern, it is possible to
Can be copied. In the manufacturing method of the present embodiment, the metal distribution
At the same time as etching of the line layer 18, an inorganic mask and anti-reflection
Si as the film 20_xO_yN_z: Reducing the thickness of the H film
(Or Si_xO_yN_z: Complete removal of H film
Can be performed), and the step on the metal wiring layer 18 can be further
It does not increase.

Further, in the manufacturing method of the present embodiment, the indispensable antireflection film 20 can also serve as an inorganic mask, so that the manufacturing process of the present embodiment has a smaller number of steps than the conventional manufacturing process. Do not increase at all. Metal wiring layer 1
After the formation of the fine pattern in FIG.
As shown in (F), after an interlayer insulating layer 32 made of silicon oxide or the like is formed, a contact hole 34 having a fine pattern is formed in the interlayer insulating layer 32. The contact hole of this fine pattern can be formed by a manufacturing method using the above-described high absorption layer and antireflection film.

Thereafter, a buried plug layer 36 is formed in the contact hole 34 by selective growth of tungsten or the like, and an upper metal wiring layer 38 is formed thereon. The embodiment of the present invention can be applied to the case where the upper metal wiring layer 38 is processed into a fine pattern.

[0062] Example 2 In this Example, as shown in Example 1, Si _x O _y N _z as an inorganic film and antireflection film: H film, except that was formed by the following method, Example In the same manner as in Example 1, a fine pattern was formed on the semiconductor device.

That is, in this embodiment, the Si _x O
_y N _z: H film, parallel plate type plasma CVD method, ECR
Plasma CVD method or bias ECR plasma C
Using a VD method and a microwave (2.45 GHz), a mixed gas of SiH ₄ + O ₂ + N ₂ or SiH 4
_A film was formed using a mixed gas of ₄ + N ₂ O.

[0064] EXAMPLE 3 In this example, as shown in Example 1, as an inorganic film and an antireflection film Si _x O _y N _z: except that the H film was formed by the following method, Example 1 In the same manner as described above, a fine pattern was formed on the semiconductor device.

That is, in this embodiment, the Si _x O
_y N _z: H film, parallel plate type plasma CVD method, ECR
Using a plasma CVD method and a bias ECR plasma CVD method, using microwave (2.45 GHz),
H ₄ + O ₂ + N ₂ mixed gas or SiH ₄ + N ₂
A film was formed using a mixed gas of O and Ar as a buffer gas.

[0066] EXAMPLE 4 In this example, shown in Example 1, as an inorganic film and an antireflection film Si _x O _y N _z: except that the H film was formed by the following method, Example 1 In the same manner as described above, a fine pattern was formed on the semiconductor device.

That is, in this embodiment, the inorganic film and the anti-reflection film are formed by a parallel plate type plasma CVD method, ECRCVD.
Method or bias ECRCVD method,
₄ + O ₂ + N ₂ mixed gas or SiH ₄ + N ₂ O
Was formed using a mixed gas of

[0068] Example 5 In this example, as shown in Example 1, as an inorganic film and an antireflection film Si _x O _y N _z: except that the H film was formed by the following method, Example 1 In the same manner as described above, a fine pattern was formed on the semiconductor device.

That is, in this embodiment, the inorganic film and the antireflection film are formed by using a mixed gas of SiH ₄ + O ₂ + N ₂ using a parallel plate type plasma CVD method, an ECR plasma CVD method, or a bias ECR plasma CVD method. Or S
A film was formed using a mixed gas of iH ₄ + N ₂ O and Ar as a buffer gas.

[0070] EXAMPLE 6 In this example, as shown in Example 1, Si _x O _y N _z as an inorganic film and an antireflection film: instead of an H film, Si _x N _y
Then, a fine pattern was formed on the semiconductor device in the same manner as in Example 1 except that a film was formed by the following method.

That is, in this embodiment, the inorganic film and the anti-reflection film are formed by using a parallel plate plasma CVD method, an ECR plasma CVD method, or a bias ECR plasma CVD method and using microwaves (2.45 GHz). , Si
H ₄ + NH ₃ mixed gas or SiH ₂ Cl ₂ + NH ₃
Film formation was performed using a mixed gas.

[0072] In Example 7 This example, shown in Example 1, Si _x O _y N _z as an inorganic film and an antireflection film: instead of an H film, Si _x N _y
Then, a fine pattern was formed on the semiconductor device in the same manner as in Example 1 except that a film was formed by the following method.

That is, in the present embodiment, the inorganic film and the antireflection film are formed by using a parallel plate plasma CVD method, an ECR plasma CVD method, or a bias ECR plasma CVD method and using microwaves (2.45 GHz). , Si
H ₄ + O ₂ mixed gas or SiH ₂ Cl ₂ + NH ₃
A film was formed using a mixed gas and Ar as a buffer gas.

[0074] In Example 8 This example, shown in Example 1, Si _x O _y N _z as an inorganic film and an antireflection film: instead of an H film, Si _x N _y
Then, a fine pattern was formed on the semiconductor device in the same manner as in Example 1 except that a film was formed by the following method.

That is, in the present embodiment, the inorganic film and the antireflection film are formed by using a parallel plate plasma CVD method, an ECR plasma CVD method, or a bias ECR plasma CVD method to form a mixed gas of SiH ₄ + O ₂ or SiH _2. C
It was deposited with l2 + NH ₃ mixed gas.

[0076] In Example 9 This example, shown in Example 1, Si _x O _y N _z as an inorganic film and an antireflection film: instead of an H film, Si _x N _y
Then, a fine pattern was formed on the semiconductor device in the same manner as in Example 1 except that a film was formed by the following method.

That is, in this embodiment, the inorganic film and the anti-reflection film are formed by using a parallel plate plasma CVD method, an ECR plasma CVD method, or a bias ECR plasma CVD method to form a mixed gas of SiH ₄ + O ₂ or SiH _2. C
Using a mixed gas of l 2 + NH _{3 and} Ar gas as a buffer gas
Was used to form a film.

[0078]

As described above, according to the method for manufacturing a fine pattern according to the present invention, even in the case of etching a metal layer in which a dimensional conversion difference at the time of etching is a problem, the inorganic layer can be formed without increasing the number of steps. By using the mask method, a good and stable mask pattern can be formed even if the mask pattern is fine. The method for manufacturing a fine pattern according to the present invention can be suitably used for a method for manufacturing a semiconductor device on which a fine pattern is formed.

According to the present invention, when a semiconductor mask pattern on a metal wiring having a step structure is formed by using i-line light or light having a shorter wavelength, for example, i-line, KrF, or ArF excimer laser, reflection occurs. By forming an inorganic film and an anti-reflection film having both an anti-reflection effect and an inorganic mask function on a base substrate, a good and stable mask pattern can be formed without increasing the number of steps.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing light interference in a resist film.

FIG. 2 is a diagram showing a standing wave effect on a silicon substrate.

FIG. 3 is a diagram showing a standing wave effect on aluminum silicide.

FIG. 4 is a diagram illustrating a standing wave effect on tungsten silicide.

FIG. 5 is a diagram for estimating the effect of a step on the standing wave effect.

FIG. 6 is a graph showing a relationship between a variation in the amount of absorbed light and a variation in pattern dimension.

FIG. 7 is a diagram showing a standing wave effect on a silicon substrate.

FIG. 8 is a diagram showing contour lines of the amount of absorbed light when the optical constants n and k are changed while the thickness of the antireflection film is fixed.

FIG. 9 is a diagram showing contour lines of the amount of absorbed light similar to FIG. 8 for other different resist film thicknesses.

FIG. 10 is a diagram showing contour lines of the amount of absorbed light similar to FIG. 8 for other different resist film thicknesses.

FIG. 11 is a diagram showing contour lines of the amount of absorbed light similar to FIG. 8 for other different resist film thicknesses.

[12] FIG. 12 (A), (B) is a graph showing changes in optical constants of the Si _x O _y N _z in the case of changing the manufacturing conditions.

Figure 13 is a tungsten silicide base substrate, Si _x O _y N _z: is a diagram showing an anti-reflection effect of the H film was deposited.

Figure 14 is Si _x O _y N _z on an aluminum silicon silicide substrate: is a diagram showing the reflection preventing effect in the case of H film.

[15] Figure 15 is a silicon substrate Si _x O _y N _z:
It is a figure which shows the antireflection effect at the time of forming a H film.

FIGS. 16A to 16D are main-portion cross-sectional views showing a process of manufacturing a semiconductor device according to one embodiment of the present invention.

17 (E) and 17 (F) are cross-sectional views of essential parts showing a manufacturing process continued from FIG. 16 (D).

Figure 18 is Si _x O _y N _z on an aluminum silicon silicide underlying substrate: is a diagram showing an anti-reflection effect due to the H film.

Figure 19 is an aluminum silicon silicide base on a Si substrate _x O _y N _z: H film showed an anti-reflection effect due to the film formation, as compared to FIG. _{18, Si x O y N z} : H film FIG. 4 is a diagram in which the optical conditions and the film thickness are changed.

[Explanation of symbols]

 Reference Signs List 2 semiconductor substrate 4 polysilicon film 6 tungsten silicide film 8 gate electrode 10 interlayer insulating film 18 metal wiring layer 20 inorganic film / anti-reflection film 24 resist film 26, 28, 30 fine pattern

Claims (3)

(57) [Claims] 1. An undersubstrate having a refractive index (n) of 1.7 or less.
2.4 or less, and the extinction coefficient (k) is 0.85 or less
Si _x whose thickness is below 100-500 nm
O _y N _z: forming an H film antireflection film composed of, on the antireflection film, forming a resist film, the resist film, a wavelength shorter than the i-line or i-line A step of exposing using a light beam to transfer a mask pattern to a resist film, and etching the antireflection film using the resist film to which the mask pattern has been transferred as a mask, and forming a mask pattern on the antireflection film. A method for producing a fine pattern, comprising: a step of transferring; and a step of etching the base substrate using the antireflection film to which the mask pattern has been transferred as a mask, and transferring the mask pattern to the base substrate. Wherein the surface of the base substrate, the manufacturing method of a fine pattern according to claim 1, wherein the conductive layer. 3. A method of manufacturing a semiconductor device, wherein the method of manufacturing a fine pattern according to claim 1 is used in a process of manufacturing a semiconductor device.