JPH07199447A - Single-layer, half-tone phase-shift mask and its manufacture - Google Patents

Abstract

PURPOSE:To provide a single-layer, half-tone phase-shift mask which can reduce manufacturing processes and the occurrence of defects, control the amount of phase shift, and control light intensity transmittance to the appropriate value and a method for manufacturing the same. CONSTITUTION:A single-layer,-half-tone phase-shift mask comprises a substrate 10 and a single semishielding layer 22 serving also as a shifter layer formed on the substrate and having semishielding films formed in a desired pattern, the semishielding films being made from a material with a complex index of refraction whose real and imaginary number parts can be varied depending on the film-forming conditions of CVD method. A method for manufacturing the mask comprises a process in which, using on the substrate the material with a complex index of refraction whose real and imaginary number parts can be varied depending on the film-forming conditions of CVD method, semishielding films are formed from the material using CVD method and a single semishielding layer serving also as a shifter layer is formed by the selective removal of part of the semishielding films.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single-layer halftone type phase shift mask in which a shifter layer and a semi-shielding layer are integrated.

[0002]

2. Description of the Related Art A photomask used in a pattern transfer process, that is, a so-called lithography process in manufacturing a semiconductor device is used for transferring a pattern shape on the photomask onto a resist material formed on a wafer. The dimensions of pattern processing in semiconductor devices and the like are becoming finer year by year. A conventional photomask provided only with a pattern region composed of a light-shielding region and a light-transmitting region cannot obtain a resolution of about the wavelength of the exposure light of the exposure apparatus used in the lithography process, and the semiconductor device It is becoming difficult to obtain the required resolution in the manufacture of the above. Therefore, in recent years, so-called phase shift masks having a phase shift region that makes the phase of light different have been used in place of such conventional photomasks. By using a phase shift mask, it is possible to form a fine pattern that cannot be formed by a conventional photomask.

The pattern area in the conventional phase shift mask is a phase shift area made of a light transmitting area, a light shielding area for shielding light, and a light transmitting material for transmitting light having a phase different from the phase of light transmitted through the light transmitting area. It consists of 7A and 7B are schematic partial cutaway views of a pattern area of a typical conventional edge-enhanced phase shift mask. In the figure, 210 is a base made of a transparent material substrate, 212 is a light transmission region, 214 is a light shielding region, 216 is a phase shift region, and 218 is a light transmission material layer. By providing the light transmitting material layer 218, the light transmitting region 212 is provided.
It is possible to change the phase of the light transmitted through the phase shifter and the phase of the light transmitted through the phase shift region 216 by 180 degrees, for example.

In the conventional phase shift mask, a fine pattern cannot be formed unless the shape or position of the phase shift region is precisely controlled. In addition, depending on the pattern shape, the phase shift region may cause light interference even in other light transmitting regions that should not receive light interference. In such a case, the phase shift region cannot be formed.

As a kind of phase shift mask for solving the problems of these conventional phase shift masks, a pattern region composed of a semi-shielded region and a light transmission region is provided,
There is a halftone phase shift mask in which the phase of light transmitted through the semi-shielded region and the phase of light transmitted through the light transmissive region are different. In the halftone phase shift mask, the semi-shielded region is formed on almost the entire surface except the light transmission region. The halftone type phase shift mask has an advantage that not only the problems of the conventional phase shift mask can be solved, but also the fabrication thereof is easy, and the degree of generation of defects during mask fabrication is low.

FIGS. 8A and 8B are schematic partial sectional views of a pattern region of a conventional halftone phase shift mask. In FIG. 8, 110 is a base made of a transparent material substrate, 112 is a light transmission region, and 120 is a semi-shielded region. The semi-light-shielding region 120 is composed of a semi-light-shielding layer 122 made of, for example, Cr and a shifter layer (light-transmitting material layer) 124 made of, for example, SOG (Spin On Glass). The shifter layer 124 has a function of making the phase of light transmitted through the light transmission region 112 and the phase of light transmitted through the semi-shielded region 120 different, for example, by 180 degrees.

In the halftone phase shift mask, the amplitude transmittance of the semi-shielded region 120 is greater than 0 and does not resolve the resist material, for example, 20 to 4.
It is about 5%. If expressed in terms of light intensity transmittance,
It is about 20%. Then, in order to transfer the pattern shape formed in the pattern area of the mask onto the resist material formed on the wafer, light passing through the semi-shielded area 120 having a predetermined light intensity transmittance and phase, and semi-shielded light For example, the light transmission region 1 having a phase difference of 180 degrees from the region 120
The interference of the light passing through 12 is used.

[0008]

A halftone phase shift mask has a pattern transfer performance which is almost the same as that of a conventional outrigger type or rim type phase shift mask. However, in the conventional halftone phase shift mask, the semi-shielding region 120 is the semi-shielding layer 1.
Since it is composed of 22 and the shifter layer 124, two film forming steps are required to form the semi-shielded region 120, and two etching steps are required because the etching conditions of Cr and SOG are different. The manufacturing process is complicated. Further, as the number of film forming steps and etching steps increases, the probability that defects will occur in the halftone phase shift mask also increases. Furthermore, the shifter layer 124 is
In the case of being composed of G, there is also a problem that so-called scrub cleaning cannot be performed because the adhesion of SOG to the base is low.

Cr-O formed by reactive sputtering
A single-layer halftone phase shift mask using a film or Cr-ON film is described in, for example, "Development of Single-Layer Halftone Phase-Shift Mask", Nobuyuki Yoshioka et al., Proc. , 28a-SHF-2
4 is known. This document, by performing reactive sputtering using a Cr target and Ar + O ₂ or Ar + O ₂ + N ₂ gas, forming a film of Cr-O or Cr-ON film is disclosed. Then, by changing the sputtering conditions, the real number part and the imaginary number part of the complex refractive index of the Cr-O or Cr-ON film are changed, thereby changing the light transmittance and the phase change of the Cr-O or Cr-ON film. Have control. The technique disclosed in this document is effective when i-line (λ = 365 nm) is used, but when light of shorter wavelength such as KrF excimer laser light is used, the technique of the Cr-O or Cr-ON film is used. There is a problem that it becomes impossible to control each of the film thickness, the amount of phase change, and the light transmittance to appropriate values. That is, Cr-O or Cr
In the -ON film, the film thickness is determined when the light transmittance is determined, and the phase change amount is uniformly determined when the film thickness is determined.

Therefore, the object of the present invention is to reduce the number of manufacturing steps, to reduce the occurrence of defects, and to control the phase change amount and the light intensity transmittance to appropriate values. A layer halftone type phase shift mask and a method for manufacturing the same.

[0011]

A single-layer halftone phase shift mask of the present invention for achieving the above object comprises a substrate and a semi-shielding film formed on the substrate in a desired pattern shape. And a semi-light-shielding layer having a single layer, and the semi-light-shielding film is made of a material that can change the values of the real number part and the imaginary number part of the complex refractive index depending on the film forming conditions of the CVD method.

In the single-layer halftone phase shift mask of the present invention, the light intensity transmittance required for the shifter layer / semi-light-shielding layer is T, the real part of the complex refractive index of the material is n, and the imaginary part is k. In this case, it is desirable that the semi-light-shielding film is made of a material that satisfies InT = −2π (k / (n−1)).

Alternatively, the single-layer halftone phase shift mask of the present invention comprises a base and a single-layer shifter layer / semi-light-shielding layer formed on the base and having a semi-light-shielding film formed in a desired pattern. And the semi-light-shielding film is SiO _X N _Y ,
It is characterized by being composed of SiN _x , SiO, SiO _x or SiC.

A method of manufacturing a single-layer halftone phase shift mask of the present invention for achieving the above object is a CV.
After forming a semi-light-shielding film made of this material on the substrate by the CVD method using a material that can change the values of the real number part and the imaginary number part of the complex refractive index depending on the film forming conditions of the D method, the semi-light-shielding film Is selectively removed to form a single-layer shifter layer / semi-light-shielding layer.

In the method for producing a single-layer halftone phase shift mask of the present invention, (a) the light intensity transmittance T of the shifter layer / semi-light-shielding layer is determined in advance, and the shifter layer / semi-light-shielding layer is also formed. The wavelength λ of the transmitted light is determined. (B) When the real part of the complex refractive index of the material is n, the thickness d of the shifter layer / semi-light-shielding layer is calculated from the following equation, and d = λ / 2 ( n-1) (c) When the imaginary part of the complex refractive index of the material is k, the relationship between n and k is calculated from the following equation: lnT = -2π (k / (n-1)) (d) n It is desirable to determine the film forming conditions of the semi-light-shielding film by the CVD method so that k and k become the values obtained from the above relationship, and form the semi-light-shielding film of thickness d based on the film-forming conditions. .

[0016] Alternatively, a method of producing a single-layer halftone type phase shift mask of the present invention, on a substrate, SiO _X
From the step of forming a single-layer shifter layer / semi-light-shielding layer by selectively removing the semi-light-shielding film after forming a semi-light-shielding film made of N _Y , SiN _x , SiO or SiO _x by a CVD method. It is characterized by being formed.

Furthermore, in the method for manufacturing a single-layer halftone phase shift mask of the present invention, a semi-light-shielding film made of SiC is formed on a substrate, and then the semi-light-shielding film is selectively removed. It is characterized by comprising a step of forming a shifter layer and a semi-light-shielding layer of the layer.

When a transfer pattern shape or the like is formed on a resist material formed on a wafer by exposure light, one used for reduction projection is called a reticle, and one used for one-to-one projection is called a mask. In some cases, a reticle equivalent to the master disc may be referred to as a reticle, and a duplicate thereof may be referred to as a mask. In this specification, a reticle and a mask having various meanings as described above are collectively referred to as a mask. .

[0019]

When the value of the real part of the complex refractive index of the material forming the shifter layer and the semi-light-shielding layer is n and the value of the imaginary part is k, the light having the light intensity I ₀ and the wavelength λ is shifted with the film thickness d. When incident on the layer / semi-light-shielding layer, the light intensity I of the light after passing through the shifter layer / semi-light-shielding layer is represented by I = I ₀ · exp {(-4πkd) / λ}. Therefore, the light intensity transmittance T is expressed by T = I / I ₀ = exp {(-4πkd) / λ} formula (1). On the other hand, when the phase of the light transmitted through the semi-shielded region where the shifter layer / semi-shielded layer is formed and the phase of the light transmitted through the light transmission region where the shifter layer / semi-shielded layer is not formed are changed by, for example, 180 degrees Therefore, the film thickness d of the shifter layer / semi-light-shielding layer needs to satisfy the relationship of d = λ / 2 (n-1) formula (2). Therefore, lnT = (-4πkd) / λ = -2πk / (n-1) Formula (3) is derived from Formula (1) and Formula (2).

Therefore, the values of n and k can be set to desired values by forming the semi-shielding film from a material that can change the values of the real number part and the imaginary number part of the complex refractive index depending on the film forming conditions such as the CVD method. And the phase of the light that has passed through the light transmission area,
It is possible to control the light intensity transmittance of the light passing through the shifter layer / semi-light-shielding layer to a desired value while controlling the phase of the light passing through the shifter layer / semi-light-shielding layer. The halftone phase shift mask of the present invention is a single layer, and does not require a two-step film forming step or etching step.

The material forming the semi-light-shielding film is SiO _x.
When selected from N _Y , SiO, SiO _X , SiN _X, or SiC, unlike the case of using Cr, the film thickness of the semi-light-shielding film,
It is possible to control the respective values of the phase change amount and the light intensity transmittance to appropriate values. Furthermore, CVD from these materials
By forming the semi-light-shielding film by a method or the like, the adhesion between the shifter layer / semi-light-shielding layer and the substrate can be kept high, and so-called scrub cleaning can be performed.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described based on embodiments with reference to the drawings.

(Embodiment 1) The single-layer halftone phase shift mask of the present invention is a substrate made of a transparent material substrate (eg, quartz substrate), as shown in the schematic partial sectional view of the pattern region in FIG. 10 and a shifter layer / semi-light-shielding layer 22 formed on the substrate 10. The shifter layer / semi-light-shielding layer 22 can be obtained by forming the semi-light-shielding film into a desired pattern shape. The semi-light-shielding film is made of a material capable of changing the values of the real number part (n) and the imaginary number part (k) of the complex refractive index depending on the film forming conditions of the CVD method. The phase of light transmitted through the semi-shielded region 20 where the shifter layer / semi-shielded layer 22 is formed and the phase of light transmitted through the light transmission region 12 where the shifter layer / semi-shielded layer 22 is not formed are, for example, 180.
Different.

As a material for forming the semi-light-shielding film, lnT = -2π (k / (n-1)) is satisfied, where T is a light intensity transmittance required for the shifter layer / semi-light-shielding layer 22. The material may be selected. In Example 1, SiO _X N _Y was specifically selected as this material. Note that the conditions for forming the semi-shielding film, hydrogen is incorporated into SiO _X N _Y, they may have the form of SiO _X N _Y H _Z, such forms are also herein SiO
It is included in _X N _Y.

SiO _X N _Y can be formed by a CVD method. In this case, for example, SiH ₄ and N ₂ O are used as the source gas. It is known that changing the gas supply ratio of SiH ₄ / N ₂ O can change the values of the real part (n) and the imaginary part (k) of the complex refractive index of the formed SiO _x N _y . For example, the document "Practical resolution e
nhancement effect by new complete anti-reflective
layer in KrF laser lithography ", T. Ogawa, et. a
l., SPIE vol. 1927, Optical / Laser Microlithograph
See y, Vl (1993), pp.263-274.

According to this document, when KrF excimer laser light (λ = 248 nm) is used, as shown in FIG. 2 (A), regardless of the gas supply ratio of SiH ₄ / N ₂ O, n The value of is almost constant (n is about 2.1). On the other hand, as shown in FIG. 2B, the value of k increases as the gas supply ratio of SiH ₄ / N ₂ O increases. Note that λ
The graph of the experimental value which calculated | required the relationship of n and k in = 248nm is shown in FIG. Therefore, if the light intensity transmittance T is determined in advance, the relation between k and n can be obtained from the following equation obtained by modifying the equation (3). k = (-lnT / 2π) (n-1) Formula (4)

As shown in FIG. 3, a linear function of k obtained by using n as a variable with T as a parameter, and n and k
The desired phase change amount (180 degrees) and the desired light intensity transmittance (T) can be obtained by finding the intersection point (n, k) of the graph of the experimental values for which the relationship of That is, such n and k
The film forming conditions of the CVD method that obtain the value of are obtained by conducting a test in advance. Then, if a semi-light-shielding film having a thickness d is formed under such a CVD film forming condition, the light-transmitting region 12 and the phase of the light transmitted through the semi-light-shielding region 20 have a predetermined light intensity transmittance T. The phase of the light transmitted through can be changed, for example, by 180 degrees.

The method of manufacturing the single-layer halftone phase shift mask of Example 1 will be described below. The light intensity transmittance T of the shifter layer / semi-light-shielding layer 22 is set to, for example, 10%, and the wavelength λ of light transmitted through the shifter layer / semi-light-shielding layer 22 is set to 248 nm which is the wavelength of the KrF excimer laser light. Under such a condition, T = 0.1 in the equation (4) from FIG.
And a linear function substituting for n and k at λ = 248 nm
The value of (n, k) at the intersection with the graph of the experimental value for which the relationship of (1) is obtained is approximately (1.94, 0.34).

Although it depends on the PECVD apparatus, etc., in order to obtain such a value of (n, k), a test for forming a SiO _x N _y film by changing the gas supply ratio of SiH ₄ / N ₂ O is performed. went. Gas used: SiH ₄ / N ₂ O = 50 / 25-100sc
cm Film forming temperature: 360 ° C. RF power: 190 W Pressure: 3.3 × 10 ² Pa (2.5 Torr) Film forming time: 5 seconds SiH ₄ gas supply amount was fixed at 50 sccm and N ₂ O gas supply amount was changed. The values of n and k of the semi-light-shielding film obtained by changing from 25 to 100 sccm are shown in FIG. From FIG. 4, (n, k)
= (1.94, 0.34), SiH ₄ /
It is understood that the semi-light-shielding film made of SiO _X N _Y should be formed under the condition of N ₂ O = 50/56 sccm.

As the gas used, in addition to SiH ₄ / N ₂ O, SiH ₄ / O ₂ / N ₂ SiH ₄ / N ₂ O / Ar SiH ₄ / O ₂ / N ₂ / Ar SiH ₄ / the _{N 2 O / N 2 / Ar} SiH 4 / NH 3 / O 2 can be exemplified. If a graph similar to that of FIG. 4 is created using such various gases, the desired (n,
The CVD conditions for obtaining the combination of k) can be determined.

In order to manufacture the single-layer halftone phase shift mask of the present invention, a parallel plate PE (Plasma-Enhan
First, a semi-light-shielding film is formed on the surface of the substrate 10 made of quartz by PECVD method using a ced) CVD apparatus, ECR plasma CVD method or bias plasma CVD method. The film forming conditions are as described above. The thickness d of the semi-light-shielding film was set to a value satisfying d = λ / 2 (n−1), that is, 132 nm.

Next, a resist film sensitive to electron beams is applied on the semi-shielding film by, for example, spin coating, and then,
Drawing with an electron beam from a drawing device and development of the resist film were performed.

After that, the semi-light-shielding film is etched by the method illustrated below to selectively remove the semi-light-shielding film,
Then, the resist film is removed. Thus, the single-layer shifter layer / semi-light-shielding layer 22 shown in FIG. 1 could be formed. (A) CHF ₃ (50~100sccm) and O ₂ (3~20sc
cm) mixed gas is used and pressure of about 2 Pa is 100 to
Etching by the reactive ion etching (RIE) method in which the power of 1000 W is applied to enhance the ionicity. (B) C ₄ F ₈ (30 to 70 sccm) and CHF ₃ (10 to ₃ )
0 sccm) mixed gas is used, and pressure is about 2 Pa.
RI with high ionicity by applying power of 0 to 1000W
Etching by E method. Alternatively, (C) S ₂ F ₂ (5 to 30 sccm) gas is used, and etching is performed by the RIE method in which the ionicity is enhanced by applying a power of 100 to 1000 W under a pressure of about 2 Pa.

(Embodiment 2) Unlike Embodiment 1, Embodiment 2 uses SiN _x as a material for the semi-light-shielding film.
Was used. The structure of the single-layer halftone phase shift mask of the second embodiment is similar to that of the single layer halftone phase shift mask of the first embodiment shown in FIG. 1, and detailed description thereof will be omitted.

SiN _x can be formed by a PECVD method using a parallel plate PECVD apparatus, an ECR plasma CVD method or a bias plasma CVD method. For example, in the PECVD method, when SiH ₄ / NH ₃ gas is used and the gas supply ratio of SiH ₄ / NH ₃ is changed, the relationship between n and k similar to that shown in FIG. 3 is obtained.
That is, when KrF excimer laser light (λ = 248 nm) is used, the value of n is almost constant (n is about 1.9 to 2.2) regardless of the gas supply ratio of SiH ₄ / NH _3.
Is. On the other hand, the value of k increases as the gas supply ratio of SiH ₄ / NH ₃ increases. Therefore, similarly to the first embodiment, if the light intensity transmittance T is determined in advance, the relationship between k and n can be obtained from the equation (4). If a semi-light-shielding film made of SiN _{x with a} thickness d is formed under the predetermined CVD film formation conditions obtained from this relationship, the semi-light-shielding film 20 has a predetermined light intensity transmittance T and is transmitted through the semi-light-shielding region 20. It is possible to change, for example, 180 degrees between the phase of the generated light and the phase of the light transmitted through the light transmission region 12.

As the gas used, in addition to SiH ₄ / NH ₃ , SiH ₂ Cl ₂ / NH ₃ SiH ₂ Cl ₂ / NH ₃ / Ar SiH ₄ / N ₂ / Ar Si ₂ H ₆ / NH _{3 [(CH 3) 2 N]} 3 SiN 3 [(C 2 H 5) 2 N] 3 SiN 3 (CH 3) 3 SiN 3 (C 2 H 5) 3 SiN 3 (Cp 2 N) 3 SiN 3 Cp 3 SiN ₃ can be exemplified. Cp is an abbreviation for cyclopentane. If a graph similar to that of FIG. 4 is created using such various gases, the CVD conditions for obtaining a desired (n, k) combination can be obtained. The etching of the semi-light-shielding film made of SiN _x can be performed by the same method as in the first embodiment.

Example 3 In Example 3, unlike Example 1, SiO was used as the material for the semi-light-shielding film. The structure of the single-layer halftone phase shift mask of Example 3 is also the same as that of the single-layer halftone phase shift mask of Example 1 shown in FIG. 1, and detailed description thereof will be omitted.

The semi-light-shielding film made of SiO is, for example, Si
The film can be formed by a CVD method using H ₄ / O ₂ / N ₂ gas or SiH ₄ / N ₂ O / N ₂ gas. As film forming conditions, for example, the film forming temperature is room temperature to 500 ° C. and the pressure is 0.
It can be 01 to 10 Pa. On the other hand, the formed semi-light-shielding film made of SiO is CF ₄ , CHF ₃ , C ₂ F ₆ ,
RIE in which C ₃ F ₈ , SF ₆ or NF ₃ based etching gas is used as an etchant and Ar is added to enhance ionicity
Can be etched by the method.

SiO formed under various CVD film forming conditions
The relationship of (n, k) of the semi-light-shielding film made of is obtained. on the other hand,
Similar to the first embodiment, the light intensity transmittance T is determined in advance. By this, the relation between k and n can be obtained from the equation (4), and if a semi-light-shielding film made of SiO with a thickness of d is formed under a predetermined CVD film forming condition obtained from this relation,
It has a predetermined light intensity transmittance T and, moreover, the semi-shielded region 20.
The phase of the light transmitted through and the phase of the light transmitted through the light transmission region 12 can be changed, for example, by 180 degrees.

(Embodiment 4) Unlike Embodiment 1, Embodiment 4 uses SiO _x as a material for forming the semi-light-shielding film.
Was used. The structure of the single-layer halftone phase shift mask of the fourth embodiment is also similar to that of the single layer halftone phase shift mask of the first embodiment shown in FIG. 1, and detailed description thereof will be omitted.

The semi-light-shielding film made of SiO _X can be formed by the following method. [Parallel plate type plasma CVD
Plasma CVD method using an apparatus] Gas combination: SiH ₄ / O ₂ SiH ₄ / O ₂ / Ar [bias ECR plasma CVD method] Gas combination: SiH ₄ / O ₂ SiH ₄ / O ₂ / Ar TEOS / O ₂ SiH ₄ / N ₂ O SiH ₄ / N ₂ O / Ar

On the other hand, the formed SiO _X semi-light-shielding film can be etched under the same conditions as the etching conditions for the SiO _X N _Y semi-light-shielding film of the first embodiment.

Bias EC using SiH ₄ / O ₂ gas
A semi-light-shielding film made of SiO _{x was formed by the} R plasma CVD method under various film forming conditions (changing the gas supply ratio of SiH ₄ / O ₂ ). FIG. 5 shows the relationship (n, k) of the formed semi-shield film made of SiO _x . Similar to the first embodiment, if the light intensity transmittance T is determined in advance, the relationship between k and n can be obtained from the equation (4). Then, under a predetermined CVD film formation condition obtained from the relationship between k and n, SiO of thickness d
If a semi-light-shielding film made of _X is formed, it has a predetermined light intensity transmittance T, and the phase of light passing through the semi-light-shielding region 20 and the phase of light passing through the light-transmitting region 12 are, for example, 180.
You can change it.

As a raw material gas and a CVD method for forming a SiO _x film, TEOS, OMCTS (S
_{i 4 O (CH 3) 8} ), HMDS (Si 2 O (CH 3) 6)
And the like, or a combined use of these gases and SiH ₄ , or a plasma CVD method using a parallel plate type plasma CVD apparatus.

(Example 5) In Example 5, unlike Example 1, SiC was used as a material for forming the semi-light-shielding film. The semi-light-shielding film made of SiC can be formed by a sputtering method other than the CVD method. The structure of the single-layer halftone phase shift mask of Example 5 also
This is the same as the single-layer halftone phase shift mask of the first embodiment shown in FIG. 1, and detailed description thereof will be omitted.

The semi-light-shielding film made of SiC can be formed by the following method. [Thermal CVD Method] Combination of gases used: SiCl ₄ / C ₃ H ₈ / H ₂ SiHCl ₃ / C ₃ H ₈ / H ₂ SiCl ₄ / CH ₄ / H ₂ SiH ₄ / C ₃ H ₈ / H ₂ SiH ₄ / C ₂ H ₄ / H ₂ CVD method conditions: temperature: 100 ° C to 800 ° C pressure: 1 × 10 ^-2 to 1 × 10 ⁵ Pa, more preferably 1 × 10 ² to 1 × 10 ⁵ Pa [plasma Utilizing photochemical reaction by CVD method] Combination of used gases: Si ₂ H ₆ / Si (CH ₃ ) H ₃ / C ₂ H ₂ [ECR plasma CVD method] Combination of used gases: SiH ₄ / CH ₄ / H ₂ SiH ₄ / C ₂ H ₄ SiH ₄ / C ₂ H ₄ / H ₂ [Sputtering method] Target: SiC

On the other hand, the semi-light-shielding film made of SiC is formed by using CF ₄ , CHF ₃ , C ₂ F ₆ , C ₃ F ₈ , SF ₆ or NF ₃ based etching gas as an etchant and adding Ar. Can be etched by the RIE method with enhanced ionicity.

Using a SiH ₄ / C ₂ H ₄ / H ₂ gas, a semi-light-shielding film made of SiC was formed by a bias ECR plasma CVD method under various film forming conditions (SiH ₄ / C ₂ H ₄ gas). A film was formed by changing the supply ratio. Supply amount of used gas: SiH ₄ / C ₂ H ₄ = 5 to 10/2.
5 to 10 sccm RF power: 300 to 900 W Pressure: 0.4 × 10 ^{-2 to} 5.3 × 10 ^-1 Pa

FIG. 6 shows the relationship (n, k) of the formed semi-light-shielding film made of SiC. Similar to the first embodiment, if the light intensity transmittance T is determined in advance, the relationship between k and n can be obtained from the equation (4). Then, a SiC film having a thickness of d is formed under a predetermined CVD film formation condition obtained from the relationship between k and n.
When a semi-light-shielding film made of is formed, a predetermined light intensity transmittance T
In addition, the phase of light transmitted through the semi-shielded region 20 and the phase of light transmitted through the light transmission region 12 can be changed by, for example, 180 degrees.

Although the single-layer halftone phase shift mask and the manufacturing method thereof according to the present invention have been described based on the preferred embodiments, the present invention is not limited to these embodiments. The various conditions described in the embodiments are examples and can be changed as appropriate. The material forming the semi-light-shielding film is not limited to the examples, and any material can be used as long as it can change the values of the real number part and the imaginary number part of the complex refractive index depending on the film forming conditions of the CVD method.

[0051]

According to the single-layer halftone phase shift mask and the method of manufacturing the same of the present invention, the number of manufacturing steps can be reduced, and the number of defects can be further reduced.
Moreover, the values of the phase change amount and the light intensity transmittance can be controlled to appropriate values. The two-step film forming step and etching step are unnecessary, and furthermore, the single-layer halftone phase shift mask of the present invention can be manufactured using the conventional halftone phase shift mask manufacturing process and manufacturing apparatus.

The material forming the semi-light-shielding film is SiO _x.
When selected from N _Y , SiO, SiO _X , SiN _X, or SiC, unlike the case of using Cr, the film thickness of the semi-light-shielding film,
It is possible to control the respective values of the phase change amount and the light intensity transmittance to appropriate values. Furthermore, CVD from these materials
By forming the semi-light-shielding film by a method or the like, the adhesion between the shifter layer / semi-light-shielding layer and the substrate can be kept high, and so-called scrub cleaning can be performed. Furthermore, the material forming the semi-light-shielding film can be easily removed from the substrate, if necessary. For example, the semi-light-shielding film is made of Si
When composed of O _X N _Y , by using HF,
The semi-shading film can be easily removed from the substrate. Therefore, it is possible to reuse the substrate.

[Brief description of drawings]

FIG. 1 is a schematic partial cross-sectional view of a pattern region of a single-layer halftone phase shift mask of the present invention.

FIG. 2 is a graph showing the relationship between the wavelength of incident light and n and k with respect to the gas supply ratio of SiH ₄ / N ₂ O.

FIG. 3 is a graph showing the relationship between n and k when the SiO _x N _Y film forming conditions are changed.

FIG. 4 is a graph showing the values of n and k obtained when the film forming conditions for SiO _X N _Y were changed.

FIG. 5 shows n and k when the SiO _x film forming conditions are changed.
It is a graph which shows the relationship of.

FIG. 6 is a graph showing the relationship between n and k when the SiC film forming conditions are changed.

FIG. 7 is a schematic partial cutaway view of a pattern region of a conventional phase shift mask.

FIG. 8 is a schematic partial cross-sectional view of a pattern region of a conventional halftone phase shift mask.

[Explanation of symbols]

 10 substrate 12 light transmitting region 20 semi-shielding region 22 shifter layer and semi-shielding layer

Claims (12)

[Claims] 1. A substrate and a single-layer shifter layer / semi-light-shielding layer formed on the substrate and having a semi-light-shielding film formed in a desired pattern shape. The semi-light-shielding film is formed by a CVD method. A single-layer halftone phase shift mask made of a material capable of changing the values of the real number part and the imaginary number part of the complex refractive index. 2. When the light intensity transmittance required for the shifter layer / semi-light-shielding layer is T, the real part of the complex refractive index of the material is n, and the imaginary part is k, lnT = -2π (k / ( The single-layer halftone phase shift mask according to claim 1, wherein the semi-shielding film is made of a material satisfying n-1)). 3. A substrate and a single-layer shifter layer / semi-light-shielding layer formed on the substrate and having a semi-light-shielding film formed in a desired pattern shape. The semi-light-shielding film is made of SiO _X N _Y. A single-layer halftone phase shift mask featuring. 4. A substrate and a single-layer shifter layer / semi-light-shielding layer formed on the substrate and having a semi-light-shielding film formed in a desired pattern shape. The semi-light-shielding film is made of SiN _x. Single layer halftone phase shift mask. 5. A substrate and a single-layer shifter layer / semi-shielding layer formed on the substrate and having a semi-shading film formed in a desired pattern shape. The semi-shading film is made of SiO or SiO _x. A single-layer halftone phase shift mask featuring. 6. A substrate and a single-layer shifter layer / semi-shielding layer formed on the substrate and having a semi-shielding film formed in a desired pattern shape. The semi-shielding film is made of SiC. Single layer halftone phase shift mask. 7. A semi-light-shielding film made of the material is formed on the substrate by the CVD method using a material that can change the values of the real number part and the imaginary number part of the complex refractive index depending on the film forming conditions of the CVD method. A method of manufacturing a single-layer halftone phase shift mask, which comprises a step of forming a single-layer shifter layer / semi-light-shielding layer by selectively removing the semi-light-shielding film. (A) The light intensity transmittance T of the shifter layer / semi-light-shielding layer is determined in advance, and at the same time, the wavelength λ of light transmitted through the shifter layer / semi-light-shielding layer is determined. Where n is the real part of the complex index of refraction, the thickness d of the shifter layer / semi-light-shielding layer is calculated from the following equation: d = λ / 2 (n-1) (c) Imaginary number of complex index of the material When the part is k, the relationship between n and k is calculated from the following equation, and lnT = -2π (k / (n-1)) (d) n and k are values obtained from the above relationship. The single-layer halftone phase shift according to claim 7, wherein the film forming conditions of the semi-light-shielding film by the CVD method are determined, and the semi-light-shielding film having a thickness d is formed based on the film-forming conditions. Mask manufacturing method. 9. A single-layer shifter layer / semi-light-shielding layer is formed by forming a semi-light-shielding film made of SiO _X N _Y on a substrate by a CVD method and then selectively removing the semi-light-shielding film. A method of manufacturing a single-layer halftone phase shift mask, which comprises the steps of: 10. A step of forming a semi-light-shielding film made of SiN _x on a substrate by a CVD method, and then selectively removing the semi-light-shielding film to form a single-layer shifter layer / semi-light-shielding layer. A method for producing a single-layer halftone phase shift mask, which comprises: 11. SiO or SiO on a substrate by a CVD method
A single-layer halftone phase, comprising a step of forming a single-layer shifter layer / semi-shielding layer by selectively removing the semi-shielding film after forming a semi-shielding film made of _X. Method for manufacturing shift mask. 12. A step of forming a semi-light-shielding film made of SiC on a substrate, and then selectively removing the semi-light-shielding film to form a single-layer shifter layer / semi-light-shielding layer. And a method for manufacturing a single-layer halftone phase shift mask.