JPH09222719A - Halftone phase shift mask and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phase shift mask which is adequate for formation of fine patterns and is easily producible by providing the mask with phase shift patterns formed on a substrate transparent to exposure light and grooves for phase shifts formed by etching the transparent substrate. SOLUTION: This halftone phase shift mask includes the substrate 21 transparent to the exposure light, the phase shift patterns 23A formed on the transparent substrate 21 and the grooves 25 for the phase shift formed by etching the transparent substrate 21, by which the transmittance is made better than that of the conventional halftone phase shift mask and the surfaces of the grooves 25 for the phase shift are made uniform. The fine patterns having an excellent contrast are thus formed by using short wavelengths.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phase shift mask and a manufacturing method thereof, and more particularly to a phase shift mask suitable for forming a fine pattern and easy to manufacture.

[0002]

2. Description of the Related Art Recently, as semiconductor devices have become more highly integrated and their patterns have become finer, it has become difficult to form a pattern having a line width below a predetermined limit with a conventional photomask. became. Therefore, research on a phase shift mask (PSM) which has an excellent pattern resolution and can further reduce the critical line width (CD) is being actively conducted.

The phase shift mask includes a phase shifter which is not found in conventional photomasks. In the method of forming a pattern using the phase shift mask, the phase difference between the exposure light transmitted through the phase shifter that defines the pattern transferred onto the semiconductor substrate and the exposure light transmitted through the substrate portion where the phase shifter is not formed is Be at 180 ° to each other. Therefore, they come to cancel each other at the edges of the pattern to improve the contrast of the pattern.

Among the phase shift masks, the halftone phase shift mask, in particular, has a transmissivity of 30% or less for exposure light, is semitransparent, and uses a phase shift material capable of inverting the phase to 180 °. Form a phase shifter. The reason why the phase shifter has to be semi-transparent to the exposure light is that if the light transmitted through the phase shifter has an intensity enough to expose the photosensitive film, it becomes impossible to form a pattern. Representative examples of such a halftone phase shift material include MoSiON and Cr oxides. The halftone phase shift mask is easy to manufacture, and can be efficiently applied to the formation of a contact hole having a pattern in which a line base is densely repeated and an opening having a fine size.

FIG. 1 shows a conventional halftone phase shift mask in which a MoSiON phase shifter 3 having a thickness of d1 is formed on a transparent substrate 1.

In the halftone phase shift mask, the phase difference between the exposure light that has passed through the substrate 1 and the exposure light that has passed through the MoSiON halftone phase shifter 3 is expressed by the following equation 1 and the MoSiON halftone phase shifter 3
The exposure light drop rate with respect to is determined by Equation 2 below.

ΔΦ = 2π (n−1) d1 / λ (Formula 1) T = exp (−4πkd1 / λ) (Formula 2) where ΔΦ is the phase difference, n is the refractive index of the phase shifter, and λ
Is the wavelength of the exposure light, d1 is the thickness of the MoSiON halftone phase shifter, and k is the attenuation constant of the exposure light.

However, in photolithography using a molybdenum halftone phase shift mask, short wavelength ultraviolet rays (DUV) of 248 nm or 19 is used as exposure light.
In the case of using a 3 nm ArF excimer laser, the thickness d1 of the MoSiON halftone phase shifter 3 which makes the value of ΔΦ in the above expression 1 180 ° or more cannot have a k value that allows light to be transmitted by 5% or more. because,
This is because the values of n and k that change according to the wavelength of light are set for each substance, and the shorter the wavelength, the larger the value of k and the lower the transmittance. Therefore, when the MoSiON halftone phase shift mask uses a short wavelength light source, the effect of the phase shift is halved.

In order to solve the problem of the decrease in transmittance, a modified halftone phase shift mask as shown in FIG. 2 has been proposed.

Referring to FIG. 2, a chromium film pattern 13 for adjusting transmittance is formed on a transparent substrate 11. In addition, a phase shift groove 15 is formed by etching the substrate 11 to a depth of D1 using the chromium film pattern 13 as an etching mask.

In the MoSiON halftone phase shift mask shown in FIG. 1, the MoSiON halftone phase shifter has n and k values that can cause a phase shift while appropriately adjusting the transmittance.
The halftone phase shift mask can be formed by using only the ON halftone phase shifter layer. However, since the chrome film does not have n and k values that can both cause the transmittance adjustment and the phase shift, the chrome film pattern 13 is formed by etching only the transmittance and adjusting the substrate 11. The phase is inverted by using the groove 15 for phase shift. That is, the chrome film pattern 13 is made as thin as possible to increase the transmittance, and the value of the phase shift can be kept at 180 ° by adjusting the depth D1 of the phase shift groove 15. In this case, the etching depth D1 of the substrate is ΔФ in the above formula 1.
When π is entered, it can be easily obtained by the etching depth D1 = λ / 2 (N-1) (where N is the refractive index of the substrate 11).

For example, when the substrate 11 is made of quartz by using a light source having a wavelength of 248 nm as exposure light, the etching depth D1 of the substrate is 2480 because the N value of quartz is about 1.5.
Become Å.

However, although the halftone phase shift mask shown in FIG. 2 is advantageous for adjusting the transmittance,
When a transparent substrate is etched to cause a phase shift, the etching depth is so deep that uniform etching cannot be performed. Therefore, there is a problem that the surface of the phase shift groove 15 becomes non-uniform and the phase of the transmitted light is non-uniformly shifted.

[0014]

SUMMARY OF THE INVENTION The present invention has been devised to solve the above problems, and provides a phase shift mask suitable for forming a fine pattern and easy to manufacture. There is a purpose. Another object of the present invention is to provide a manufacturing method suitable for manufacturing the phase shift mask.

[0015]

In order to achieve the above-mentioned object, a halftone phase shift mask according to the present invention comprises a substrate transparent to exposure light, a phase shifter pattern formed on the transparent substrate, And a phase shift groove formed by etching the transparent substrate.

In the present invention, the phase shifter pattern is formed with a thickness d having a transmittance T of 5 to 30% for the exposure light, and the thickness d is determined by the following equation. d =-[lambda] 1nT / 4 [pi] k (where k is the exposure light attenuation constant due to the phase shifter pattern, and [lambda] is the wavelength of the exposure light.)

The phase shifter pattern is MoS.
It is preferably formed from any one selected from iON, SiNx, amorphous C, and CrF.

The phase shift groove has a phase difference (ΔΦ) between the exposure light passing through the phase shift groove and the exposure light passing through the phase shifter pattern of 90 to 270 °.
It is formed by etching with a depth D of ## EQU1 ## and the depth D is determined by the following equation.

D = {λ / 2 (N-1)}-{2 (n-
1) d / 2 (N-1)} (where N is the refractive index of the substrate, n is the refractive index of the phase shifter pattern, λ is the wavelength of the exposure light, and d is the thickness of the phase shifter pattern. )

Further, a light-shielding film pattern is further provided on a predetermined region of the phase shifter pattern, and the light-shielding film pattern has a transmittance of 5 to 30% with respect to the exposure light.
It is desirable to be formed from any one selected from Cr, Al, and MoSi.

In order to achieve the above other object, the method of manufacturing a halftone phase shift mask according to the present invention comprises the steps of forming a phase shifter pattern on a substrate transparent to exposure light, and etching the phase shifter pattern. Etching the substrate as a mask to form a phase shift groove.

In order to achieve the above other object, the method of manufacturing a halftone phase shift mask according to the present invention comprises:
Forming a phase shifter film and a material film having a light shielding function on a substrate transparent to exposure light; and etching the material film and the phase shifter film to form a material film pattern and a phase shifter pattern, Forming a phase shift groove by etching the substrate using the material film pattern and the phase shifter pattern as an etching mask; and forming a light blocking film pattern by patterning the material film pattern formed on the phase shifter pattern. And a forming step.

In the method of manufacturing the halftone phase shift mask, the phase shifter pattern is MoSiO.
It is formed of any one selected from N, SiNx, amorphous C, and CrF, and is 5 to 30 with respect to the exposure light.
The thickness d is preferably formed to have a transmittance T of%, and the thickness d is determined by the following equation.

D = -λ1nT / 4πk (where k is the depletion constant of the exposure light, λ is the wavelength of the exposure light), and the phase shift groove is exposed after passing through the phase shift groove. The depth D at which the phase difference (ΔΦ) between the light and the exposure light passing through the phase shifter pattern is 90 to 270 °.
The depth D is determined by the following equation.

D = {λ / 2 (N-1)}-{2 (n-
1) d / 2 (N-1)} (where N is the refractive index of the substrate, n is the refractive index of the phase shifter pattern, λ is the wavelength of the exposure light, and d is the thickness of the phase shifter pattern. )

The material film having the light shielding function is C
It is desirable to be formed from any one selected from r, Al, and MoSi.

The phase shift mask according to the present invention may have a higher transmittance than the conventional phase shift mask. Moreover, since the phase shift groove formed by etching the transparent substrate is not deep, a uniform surface can be formed. Therefore, it is possible to form a fine pattern with improved contrast using a short wavelength light source.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

Halftone Phase Shift Mask First Embodiment FIG. 3 shows a halftone phase shift mask according to a first embodiment of the present invention. Referring to FIG. 3, a phase shifter 23 having a thickness of d2 is formed on a transparent substrate 21.
A is formed. In addition, a phase shift groove 25 formed by etching the substrate 21 to a depth of D2 is formed.

In the halftone phase shift mask, the transmittance is adjusted by adjusting the thickness d2 of the phase shifter 23A, and the phase shift value is 90 ° by adjusting the depth D2 of the phase shift groove 25. Through 270 °
Adjust to. Further, preferably, the value of the phase shift is 1
Adjust to 80 °.

In the present invention, the phase shifter 23A
Is preferably formed from any one selected from MoSiON, SiNx, amorphous C, and CrF.
The light transmittance of the phase shifter 23A is preferably about 5 to 30%, more preferably about 5 to 15%.

The values of the thickness d2 of the phase shifter 23A and the depth D2 of the phase shift groove 25 suitable for the present invention are obtained as follows.

First, in the conventional halftone phase shift mask, the transmittance T1 of the phase shifter (3 in FIG. 1) and its thickness d1 are already known. The attenuation constant k is as follows. k = -λ1nT1 / 4πd1

By substituting the k value thus obtained and the transmittance T2 (T2> T1) desired in the present invention into the above equation 2, the thickness d2 of the phase shifter 23A of the present invention is obtained as follows. To be d2 = d11nT2 / InT1

By inserting d2 into the equation 1, the degree of the phase shift ΔΦ1 caused by the phase shifter 23A can be known. ΔΦ1 = 2π (n-1) d2 / λ = 2π (n-1) d1
lnT2 / 1nT1λ

Since the transmittance is increased from T1 to T2,
The thickness d2 of the phase shifter becomes smaller than the thickness d1 of the conventional phase shifter having a phase shift of 180 °. Therefore, the phase shift value ΔΦ1 also becomes smaller than 180 °. The substrate is etched at a depth of D2 in order to adjust the value of the phase shift thus reduced to 180 °. The etching depth D2 of the substrate is calculated as follows when the refractive index N of the substrate is added to the above equation (1). ΔΦ2 = (π−ΔΦ1) = 2π (N−1) D2 / λ → D2 = {λ / 2 (N−1)} − {2 (n−1) d2 /
2 (N-1)}

The etching depth D2 of the substrate obtained at this time is the etching depth D1 (= of the conventional halftone phase shift mask.
λ / 2 (N-1)) to 2 (n-1) d2 / 2 (N-
1) It becomes shallower.

That is, if the light attenuation constant k or the thickness d1 of the conventional phase shifter pattern made of the same material and the transmittance T1 for the exposure light are known, the halftone phase shifter pattern having the desired transmittance T2 according to the present invention. Two
The thickness d2 of 3A is calculated from the following expression 3 and the etching depth D of the substrate is
2 can be easily obtained from Equation 4 below.

D2 = −λ1nT2 / 4πk = d11nT2 / InT1 (Equation 3) D2 = {λ / 2 (N−1)} − {2 (n−1) d2 / 2 (N−1)} (Equation 4) (Where d1 is the thickness of the conventional phase shifter pattern,
d2 is the thickness of the phase shifter pattern of the present invention, T1 is the transmittance of the conventional phase pattern, T2 is the transmittance of the phase shifter pattern of the present invention, n is the refractive index of the phase shifter pattern of the present invention, and N is the present invention. The substrate has a refractive index, and λ is the wavelength of the exposure light. )

For example, MoSi having a transmittance of 5% in the halftone phase shift mask for DUV currently used.
The thickness of the ON phase shifter pattern is 1350Å.
Therefore, when the suitable MoSiON phase shifter pattern forming the halftone phase shift mask having the transmittance of 8% and the etching thickness of the substrate are calculated by the above equations 3 and 4, the thickness of the phase shifter pattern is 1138Å ,
The etching depth of the substrate is about 390Å.

The halftone phase shift mask formed through the above process has a high transmittance even for exposure light having a short wavelength such as a 248 nm DUV light source.
In addition, since the etching depth of the substrate is lower than that of the conventional halftone phase shift mask, it is possible to form a uniform groove surface for phase shift. Therefore, when the photolithography process is performed using the halftone phase shift mask according to the present invention, the phase difference between the light passing through the shifter pattern and the light passing through the substrate on which the shifter pattern is not formed is uniformly 180 °. As a result, destructive interference occurs at the edges of the shifter pattern, and a fine pattern with improved contrast can be formed.

Second Embodiment FIG. 4 shows a halftone phase shift mask according to a second embodiment of the present invention. The same reference numerals as those in FIG. 3 indicate the same members, and reference numeral 27A indicates a light shielding film pattern.

Unlike the halftone phase shift mask of the first embodiment shown in FIG. 3, the halftone phase shift mask of the second embodiment further includes a light shielding film pattern 27A on a predetermined area of the phase shifter 23A. doing. The reason for further forming the light shielding film pattern 27A is as follows.

If, as shown in FIG. 3, the phase shifter 2
If only 3A is formed, a small amount of light will pass through the phase shifter 23A. Therefore, when the photoresist corresponding to this portion has a step, irregular reflection may occur at that portion, and light may be focused and exposed at a specific portion of the photoresist.

When the halftone phase shift mask is relatively displaced with respect to the wafer to form a repeating pattern on the wafer, a photoresist portion corresponding to an edge of the halftone phase shift mask is overlapped. There is a fear. That is, since the light transmitted through the edge of the halftone phase shift mask is repeatedly applied to the photoresist, there is a problem that the photoresist that should not be exposed is exposed.

Therefore, the light shielding film pattern 27A is formed on a predetermined region on the phase shifter 23A to prevent the photoresist from being unnecessarily exposed.

The light shielding film pattern 27A is preferably formed of any one selected from chromium, aluminum and MoSi so as to have a transmittance of 0 to 30% with respect to the light source.

Also, after only a small amount of light source passes through the phase shifter pattern 23A, the light shielding film pattern 27 is again formed.
Since the light does not reach the photoresist finally even though the light shielding film pattern 27A is not opaque because it passes through A, the light shielding film pattern 27A does not have to be completely opaque.

Method of Manufacturing Halftone Phase Shift Mask FIGS. 5 to 7 are sectional views showing a method of manufacturing the halftone phase shift mask shown in FIG. Referring to FIG. 5, a phase shifter film 23 having a thickness of d2 is formed on a transparent substrate 21, and a photoresist pattern 24 for forming a phase shifter pattern is formed on the phase shifter film 23.

The phase shift film 23 is made of MoSiON,
It is desirable to be formed from any one selected from SiNx, amorphous C, and CrF. At the thickness d2 of the phase shifter 23, the light transmittance is preferably about 5 to 30%, more preferably about 5 to 15%.

Next, as shown in FIG. 6, the phase shifter film 23 is etched using the photoresist pattern 24 as an etching mask to form a phase shifter pattern 23A. Then, using the photoresist pattern 24 and the phase shifter pattern 23A as an etching mask, the transparent substrate 21 is etched to a depth of D2 to form a phase shift groove 25.

Finally, as shown in FIG. 7, the photoresist pattern 24 is removed to complete a halftone phase shift mask having improved exposure light transmittance and uniformity.

8 to 12 are sectional views showing a method of manufacturing the halftone phase shift mask shown in FIG. The same reference numerals as those in FIGS. 5 to 7 denote the same members.

Referring to FIG. 8, a phase shifter film 23 and a material film 27 are sequentially formed on a transparent substrate 21.
Then, a first photoresist pattern 29 is formed on the material layer 27.

The phase shifter film 23 is made of MoSiO.
It is desirable to be formed from any one selected from N, SiNx, amorphous C, and CrF. The thickness d2 of the phase shifter film 23 is preferably 5 to 30%, more preferably 5 to 15%.

The material film 27 is preferably formed of any one selected from chromium, aluminum and MoSi, and has a transmittance of about 0 to 30% with respect to exposure light.

Referring to FIG. 9, the material film 27 is patterned by using the first photoresist pattern 29 as an etching mask to form a material film pattern 27A, and then the first photoresist pattern 29 is removed.

Then, as shown in FIG. 10, the phase shifter film 23 is patterned by using the material film pattern 27A as an etching mask to form the phase shifter pattern 23A, and then the transparent substrate 21 is continuously formed to a depth of D2. Etching is performed to form a phase shift groove 25.

Next, as shown in FIG. 11, a second photoresist pattern 31 defining a light blocking film pattern is formed on the material film pattern 27A.

Finally, using the second photoresist pattern 31 as an etching mask, the material film pattern 27A is etched to form a light blocking film pattern 27B having a light blocking function, and then the second photoresist pattern 31 is removed to form a half pattern. Complete the tone phase shift mask.

[0061]

Since the halftone phase shift mask according to the present invention can easily adjust the thickness of the shifter, the transmittance of light passing through the shifter can be increased. Moreover, since the etching depth of the substrate becomes shallow, the phase shift groove having a uniform surface can be formed. Therefore, by using the halftone phase shift mask formed according to the present invention, the photolithography process can be performed using a short wavelength light source. In addition, an accurate phase shift effect can be achieved and a fine pattern with improved contrast can be formed.

The present invention is not limited to the above embodiments, and it is obvious that many modifications can be made by a person having ordinary skill in the art within the technical idea to which the present invention belongs.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a conventional halftone phase shift mask on which a MoSiON halftone phase shifter is formed.

FIG. 2 is a sectional view showing a conventional halftone phase shift mask having a chrome film pattern and a phase shift groove formed therein.

FIG. 3 is a sectional view showing a halftone phase shift mask according to a first embodiment of the present invention.

FIG. 4 is a sectional view showing a halftone phase shift mask according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a method of manufacturing the halftone phase shift mask shown in FIG.

6 is a cross-sectional view showing a method of manufacturing the halftone phase shift mask shown in FIG.

7 is a cross-sectional view showing a method of manufacturing the halftone phase shift mask shown in FIG.

8 is a cross-sectional view showing a method of manufacturing the halftone phase shift mask shown in FIG.

9 is a cross-sectional view showing a method of manufacturing the halftone phase shift mask shown in FIG.

FIG. 10 is a cross-sectional view showing the method of manufacturing the halftone phase shift mask shown in FIG.

11 is a cross-sectional view showing the method of manufacturing the halftone phase shift mask shown in FIG.

FIG. 12 is a cross-sectional view showing the method of manufacturing the halftone phase shift mask shown in FIG.

[Explanation of symbols]

1 substrate, 3 phase shifter, 11 substrate, 13 chrome film pattern, 15 phase shift groove, 21 substrate, 2
3A phase shifter, 24 photoresist pattern,
25 phase shift groove, 27 material film, 27A light-shielding film pattern, 29 first photoresist pattern, 31 second photoresist pattern

Claims (25)

[Claims] 1. A substrate comprising: a substrate transparent to exposed light; a phase shifter pattern formed on the transparent substrate; and a phase shift groove formed by etching the transparent substrate. Halftone phase shift mask. 2. The halftone phase shift mask as claimed in claim 1, wherein the phase shifter pattern is formed with a thickness d having a transmittance T of 5 to 30% with respect to the exposure light. 3. The halftone phase shift mask according to claim 2, wherein the thickness d is determined by the following equation. d =-[lambda] 1nT / 4 [pi] k (where k is the exposure light attenuation constant due to the phase shifter pattern, and [lambda] is the wavelength of the exposure light.) 4. The phase shifter pattern is MoSiO.
The halftone phase shift mask according to claim 1, wherein the halftone phase shift mask is formed of any one selected from N, SiNx, amorphous C, and CrF. 5. The phase shift groove is etched at a depth D such that a phase difference (ΔΦ) between the exposure light passing through the phase shift groove and the exposure light passing through the phase shifter pattern is 90 to 270 °. The halftone phase shift mask according to claim 2, wherein the halftone phase shift mask is formed. 6. The depth D of the phase shift groove is such that the phase difference (ΔΦ) between the exposure light passing through the phase shift groove and the exposure light passing through the phase shifter pattern is 180 °.
The halftone phase shift mask according to claim 5, wherein the halftone phase shift mask is formed by etching. 7. The halftone phase shift mask according to claim 5, wherein the depth D is determined by the following equation. D = {λ / 2 (N-1)}-{2 (n-1) d / 2 (N
-1)} (where N is the refractive index of the substrate, n is the refractive index of the phase shifter pattern, λ is the wavelength of the exposure light, and d is the thickness of the phase shifter pattern.) 8. The halftone phase shift mask as claimed in claim 1, further comprising a light blocking film pattern on a predetermined region of the phase shifter pattern. 9. The halftone phase shift mask according to claim 8, wherein the light blocking film pattern has a transmittance of 5 to 30% with respect to the exposure light. 10. The light-shielding film pattern comprises Cr, Al, M
The halftone phase shift mask according to claim 8, wherein the halftone phase shift mask is formed of any one selected from oSi. 11. A method comprising: forming a phase shifter pattern on a substrate transparent to exposure light; and etching the substrate using the phase shifter pattern as an etching mask to form a phase shift groove. A method of manufacturing a halftone phase shift mask, comprising: 12. The halftone phase shift mask according to claim 11, wherein the phase shifter pattern is formed with a thickness d having a transmittance T of 5 to 30% with respect to the exposure light. Production method. 13. The method of claim 12, wherein the thickness d is determined by the following formula. d = −λ1nT / 4πk (where k is the depletion constant of the exposure light, and λ is the wavelength of the exposure light.) 14. The phase shifter pattern is MoSi.
It is formed from any one selected from ON, SiNx, amorphous C, and CrF.
A method for manufacturing a halftone phase shift mask as described in. 15. The phase shift groove is etched at a depth D such that the phase difference (ΔΦ) between the exposure light passing through the phase shift groove and the exposure light passing through the phase shifter pattern is 90 to 270 °. 13. The method of manufacturing a halftone phase shift mask according to claim 12, wherein the halftone phase shift mask is formed. 16. The phase shift groove is etched at a depth D such that a phase difference (ΔΦ) between the exposure light passing through the phase shift groove and the exposure light passing through the phase shifter pattern is 180 °. The method for manufacturing a halftone phase shift mask according to claim 15, wherein the halftone phase shift mask is formed. 17. The method of manufacturing a halftone phase shift mask according to claim 15, wherein the depth D is determined by the following equation. D = {λ / 2 (N-1)}-{2 (n-1) d / 2 (N
-1)} (where N is the refractive index of the substrate, n is the refractive index of the phase shifter pattern, λ is the wavelength of the exposure light, and d is the thickness of the phase shifter pattern.) 18. A step of forming a phase shift film on a substrate transparent to exposure light, a step of forming a material film having a light blocking function on the phase shift film, the material film and the phase shift film. Forming a material film pattern and a phase shifter pattern by etching the working film, etching the substrate using the material film pattern and the phase shifter pattern as an etching mask to form a groove for phase shift, and the phase shifter. And a step of completing a light shielding film pattern by patterning a material film pattern formed on the pattern, the method of manufacturing a halftone phase shift mask. 19. The phase shift film is MoSiON,
The method of manufacturing a halftone phase shift mask according to claim 18, wherein the halftone phase shift mask is formed of any one selected from SiNx, amorphous C, and CrF. 20. The material film having a light-shielding function is Cr,
The method of manufacturing a halftone phase shift mask according to claim 18, wherein the halftone phase shift mask is formed of any one selected from Al and MoSi. 21. The halftone phase shift mask of claim 18, wherein the phase shift film is formed with a thickness d having a transmittance T of 5 to 30% with respect to the exposure light. Manufacturing method. 22. The method of claim 21, wherein the thickness d is determined by the following formula. d = −λ1nT / 4πk (where k is the depletion constant of the exposure light, and λ is the wavelength of the exposure light.) 23. The phase shift groove is etched at a depth D such that a phase difference (ΔΦ) between the exposure light passing through the phase shift groove and the exposure light passing through the phase shifter pattern is 90 to 270 °. 22. The method of manufacturing a halftone phase shift mask according to claim 21, wherein the halftone phase shift mask is formed by: 24. The phase shift groove is etched at a depth D such that a phase difference (ΔΦ) between the exposure light passing through the phase shift groove and the exposure light passing through the phase shifter pattern is 180 °. 24. The method of manufacturing a halftone phase shift mask according to claim 23, wherein the halftone phase shift mask is formed. 25. The method of claim 23, wherein the depth D is determined by the following formula. D = {λ / 2 (N-1)}-{2 (n-1) d / 2 (N
-1)} (where N is the refractive index of the substrate, n is the refractive index of the phase shifter pattern, λ is the wavelength of the exposure light, and d is the thickness of the phase shifter pattern.)