JP2002351049A - Photomask and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide halftone phase shifting masks having high dimensional accuracy in a high yield. SOLUTION: In the structure of the halftone phase shifting masks, the pattern comprises a laminated structure of a metal-containing thin film and a photosensitive organic film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photomask used for manufacturing semiconductor devices and electronic devices, and more particularly to a halftone phase shift mask suitable for forming a fine pattern and a method for manufacturing the same.

[0002]

2. Description of the Related Art In the manufacture of semiconductor integrated circuit devices,
A lithography technique is used as a method of transferring a fine pattern onto a semiconductor wafer. In lithography, a projection exposure apparatus is mainly used, and a pattern of a photomask mounted on the projection exposure apparatus is transferred onto a semiconductor wafer to form a device pattern.

In recent years, high integration of devices and device operation
Miniaturization of patterns to be formed to meet demands for speed improvement
Is being promoted. Halftone under such background
An exposure method called a phase shift method is used. half
Tone phase shift mask is a film that is translucent to exposure light
(Called halftone film) on a transparent substrate (blanks)
This is a mask formed on the substrate. Transmission of the film to exposure light
Rates are usually adjusted within 1% to 25%. Also this
Exposure light transmitted through the film is in phase with that without this film.
Adjusted to create a difference. Highest resolution performance
The phase difference to be drawn is 180 degrees and an odd multiple thereof,
If the angle is within 90 degrees before and after 80 degrees, there is an effect of improving resolution.
You. When using a halftone mask, the resolution is generally 5
It is known that it is improved by about 20%. Half toe
MoSi, ZrSi _xO_y, CrF_x
O_y, SiN_x, SiON and other inorganic films are used
ing. Where x and y are suffixes indicating the component ratio
is there. As description about halftone phase shift
Is disclosed, for example, in JP-A-5-181257.

[0004]

A conventional halftone phase shift mask using an inorganic film has a problem that the processing accuracy is poor and the dimensional accuracy is difficult to achieve because the thickness of the halftone film is as thick as about 100 nm. there were. In wet etching with high in-plane uniformity at the time of processing, the etching proceeds in an equal manner, so that a dimensional shift in a lateral direction is large, which is not suitable for processing such a thick film. In addition, dry etching has a problem that the in-plane uniformity of the etching is poor due to the influence of plasma rise and the flow of the etching gas. In recent lithography, it is necessary to expose a fine pattern near the resolution limit of a projection lens. In such a fine pattern near the resolution limit, the optical contrast is greatly reduced due to light diffraction, so that the MEF (Mask Error en)
In addition, a factor called a “hance factor” is added, and the dimensional accuracy of the transferred pattern becomes lower than the dimensional accuracy of the pattern on the mask. Dimension difference ΔLw on mask with MEF
Is an index indicating how much the dimensional difference ΔLm of the transferred pattern has been amplified. When the reduction ratio of the projection lens is M, it is expressed by the following equation. Here, M becomes 1/4 when a 4x lens is used, for example.

MEF = ΔLm / (M · ΔLw) In a fine pattern using a halftone phase shift mask, the MEF is usually amplified from 2 to 3, that is, the dimensional variation of the mask is amplified from 2M to 3M times and transferred. For example, when a scanner with a reduction ratio of 4 is used, the change in the transfer dimension should be 1/4 of the change in the dimension on the mask,
When MEF = 4, it is 1, which means that the dimensional change on the mask is the same as the dimensional change on the wafer. For this reason, in the case of a 100 nm node mask, a dimensional accuracy on the mask of 12 nm level has been required. The drawing dimensional accuracy on the mask is about 9 nm,
Since the dimensional variation of the etching and the in-plane distribution are about 12 nm, the yield of the halftone phase shift mask satisfying the requirement of the 100 nm node is extremely low, about 20%.
There has been a problem that the cost of a good mask is high. Further, since the yield is low, it is necessary to manufacture many masks before a good mask can be formed, and there is also a problem that the substantial TAT is low.

An object of the present invention is to provide a halftone phase shift mask having high dimensional accuracy.

Another object of the present invention is to provide a method for manufacturing a halftone phase shift mask having high dimensional accuracy at a high yield.

[0008]

The outline of typical inventions among the inventions disclosed in the present application is as follows.

As shown in FIG. 1, a transparent substrate (glass substrate)
A photomask having a halftone pattern having a laminated structure composed of a thin film attenuating film 107 containing a metal and a photosensitive organic film pattern 104 is formed on 100. Here, the pattern surface is turned up in consideration of the mask manufacturing process, but when the mask is inserted into the exposure apparatus, the direction is turned upside down and the pattern surface is turned down. Darkening film pattern 10
7 is a main component of transmittance adjustment, and a photosensitive organic film pattern is a main component of phase adjustment. With this structure, the thickness of a film requiring an etching step can be reduced, and the processing accuracy is increased. Therefore, a halftone phase shift mask having high dimensional accuracy can be manufactured with high yield.

For the purpose of simplifying the manufacturing process of a normal photomask and improving the accuracy, for example, Japanese Patent Laid-Open No. 5-28
No. 9307 discloses a method of forming a mask pattern itself with a resist film. This mask is a so-called binary mask composed of an exposure light transmitting portion and a sufficient light-shielding member, and has a different purpose, structure, and effect from the halftone mask of the present invention.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing the present invention in detail,
The meaning of the terms in the present application is as follows. 1. The terms "light-shielding region", "light-shielding film", and "light-shielding pattern" indicate that the region has an optical characteristic of transmitting less than 40% of exposure light applied to the region. Generally, those having a percentage of less than 25% are used. On the other hand, "transparent"
The term “transparent film” indicates that the film has an optical property of transmitting 60% or more of the exposure light applied to the region. Generally, 90% or more is used. 2.
“Photoresist pattern” refers to a film pattern in which a photosensitive organic film is patterned by a photolithography technique. Note that this pattern includes a simple resist film having no opening in the relevant portion.

(Embodiment 1) First, a first embodiment of the present invention
Sectional Structure of Main Part of Halftone Phase Shift Mask in Form
The overall configuration will be described with reference to FIG. "The challenge
It is a repetition of "means for solving".
00 is a glass substrate which is a transparent substrate, and 107 is a substrate for reducing exposure light.
104 is a light-sensitive organic film
It is a pattern. However, 100 glass substrates are not necessarily
SiO, not limited to glass₂Crystals and CaF₂crystal
Substrates transparent to exposure light used for pattern projection of substrates
Is good enough. Next, the manufacturing process of this mask will be described.
2 (a) to 2 (d) show the first embodiment of the present invention.
Shows a method for manufacturing a halftone phase shift mask
It is. First, as shown in FIG.
(Blanks) Dimming thin film 101 on 100
A resist film 102 is formed thereon, and a desired pattern is charged.
Drawing (103) was performed using the sagittal line. Here is the dimmer thin film
Cr was used as 101, but this is only an example and
ZrSi_xO_yFilm, SiON film, SiN film, CrF _x
Film, MoSi_xFilm, CrO_xF_yFilm, W film, Ta film, T
i film, TiN film, WN _xA film or the like can also be used. Dew
Even a thin film has a strong dimming effect against light, and also irradiates exposure light
It is desirable to use a film with high resistance,
A film containing is desirable. The thickness of the Cr film is 20 nm.
Was. At this time, the light having a wavelength of 248 nm
The transmittance is about 6.5%. Dimming resist 102
Before applying on the film 101, the light reducing film 101
It is desirable to use hydrophobic treatment with rudisilazane, etc.
No. This is the size of a later wet etching process.
Etching amount is reduced, processing accuracy is improved, and
This is because the dimensional shift is reduced. The thickness of the resist
It was 122 nm. This film has a wavelength of 248 nm.
The transmittance is about 92%, and the
This produces a phase difference of 170 degrees. Here, the resist
Positive electron beam type chemically amplified polyhydroxystyrene resin
Although dysto was used, it is not limited to this. Nuff
Non-chemically amplified resist using toquinonediazide photosensitizer
Alternatively, a PMMA-based resist can be used. Positive type
Negative resist can also be used, not limited to gyst
However, the present invention is not limited to the electron beam resist.
A resist sensitive to laser light can also be used. However
Phenol and novolak to light with a wavelength of 193 nm.
When light-absorbing groups are immobilized on the resin skeleton like resin
Except for the case, a light absorber is added to the resist from the viewpoint of light resistance.
It is better not to be. Also limited to so-called resist
SOG (Spin On) to which an acid generator is added
 Also, a photosensitive composition such as Glass) can be used.
You. SOG has high light resistance due to cure bake
have. In addition, there is a feature that it is hard to change with time. What
If a resist with less film loss during development is used, phase
It is easy to control and is preferable. Pattern size on mask is wafer
Since it is larger than the pattern size above by the reduction ratio,
0.5μm even with fine patterns)
As described above, film loss during development is small. Positive resist place
The development film veri depends on the development dissolution rate of the unexposed area.
You. For those with a high dissolution rate, there is a
However, the dissolution rate of the unexposed area is
It is possible to reduce it to 1 nm or less by slowing the degree.
is there. Since a film thickness difference of 1.5 nm results in a phase difference of about 2 degrees,
It is desirable to keep the film thickness non-uniformity to 1.5 nm or less.
No. If the film is uniformly reduced even if the developing film veri
Avoid this problem by adding corrections during clothing
It becomes possible. Then, as shown in FIG.
To align the circuit pattern 105 with the reticle.
Form resist pattern 104 on which button 106 is formed
Then, a resist cure was baked. Is an example
However, here, the baking at 110 ° C. was performed. This bake is
It is effective for performing the next etching stably.
You. After that, as shown in FIG.
Was etched to form a light reducing body pattern 107. this
Dry etching can also be used for etching
However, in this case, the c
Et etching was performed. Wet etching is par
Ticicle defects are less likely to occur and the etching surface is uniform
It has the advantage of high dimensional accuracy and high dimensional accuracy. Further
Phase control because almost no resist is etched
Another feature is that it is easy. The thickness of the film to be processed is 20 n
m, the amount of side etching during etching is small.
Absent. On the other hand, dry etching causes pinhole defects.
There is a feature that it is difficult to produce. Then, during the exposure,
A light-shielding band to prevent overlapping exposure between
It was formed by laser exposure. This is shown in Fig. 2 (d).
You. Infrared laser on the resist where the shading zone is to be formed
Irradiation with light 108, light blocking of exposure light by blackening of resist
The light-shielding band 109 in which is improved. Here in the shading zone
I will add an explanation about this. Halftone film 4-15%
Step-and-repeat to transmit a small amount of exposure light
When the mask pattern is repeatedly exposed with
Overlapping exposure occurs in the area, causing pattern failure
Therefore, an area called a light-shielding band, which has a lower transmittance, is
Formed outside the tongue region. After that, bake and harden
A foottone phase shift mask was manufactured. Bake here
Is not indispensable, but changes over time and exposure
Has the effect of improving. For example, the wavelength is around 250 nm
Baking while irradiating DUV light changes the resist shape.
Especially because the resist can be cured without
It is effective. According to this method, KrF having a wavelength of 248 nm is used.
A pattern consisting of a Cr film and a resist for excimer laser light
The phase difference between the tongue and the opening is π, and the product
The transmittance of the layer film was 6%. The transmittance is limited to 6%.
For example, the thickness of Cr is 17 nm,
Assuming that the resist film thickness is 125 nm, a phase having a transmittance of 9% is obtained.
A halftone phase shift mask with a difference of π is obtained. flat
Sufficient airflow control, heat and humidity
By performing control, the circuit pattern formation area
(104 mm x 132 mm)
The variation could be controlled to ± 1 nm. Change in thickness of shifter film
A phase difference of about 2 ° occurs at 1.5 nm. Halftone position
In the case of a phase shift mask, the Levenson phase shift mask
The transfer pattern dimensional accuracy is not sensitive to the phase difference.
Is ± 3 °. ± 5mm
Sometimes. Especially when high precision and fine pattern are required
Even in this case, the allowable phase variation is ± 2 °. Reduced in this way
When increasing the transmittance by increasing the film thickness of the optical film 101 (107)
When the thickness is small, the thickness is large when the thickness is lowered.
2 (104) by changing the thickness
Obtaining a halftone phase shift mask with optical characteristics
it can.

FIG. 3 is a top view of a halftone phase shift mask manufactured by this method. A circuit pattern 105, a light-shielding band 109, and a reticle alignment mark 106 are formed on a glass substrate 100. Generally, the detection of the reticle alignment mark can be performed without any problem if the transmittance of the field portion to the detection light is 15% or less. Here, the reticle alignment mark is formed on the halftone film. However, since a KrF excimer laser beam having a wavelength of 248 nm, which is exposure light, is used as the reticle alignment mark detection light, the transmittance of the field is 6%, and the reticle alignment mark has no problem. Could be detected. Here, the reticle alignment mark 106 is formed outside the light-shielding band 109, but this positional relationship changes depending on the system of the exposure apparatus, and the reticle alignment mark may be placed inside the light-shielding band. In this embodiment, the thickness of the film to be etched 101 is about 1 / th of the film thickness of the film to be etched (halftone film) of the normal halftone phase shift mask.
5, the pattern dimensional accuracy of the halftone phase shift mask manufactured according to the present embodiment is 9n.
m was extremely high. In the conventional method, it was 15 nm. (Embodiment 2) In Embodiment 2, the resist film thickness in Embodiment 1 is 383 nm, and the phase difference of the halftone pattern portion is 3π. By increasing the thickness of the resist in this manner, the occurrence of pinhole defects during wet etching can be prevented, and a halftone phase shift mask having a low defect density can be obtained. Note that the pinhole defect still generated is due to defect correction by carbon deposition used in a normal halftone phase shift mask, and the black defect generated by particle generation is FIB.
Was able to correct the defect. Also, defect inspection could be performed in the same manner as a normal halftone phase shift mask. (Embodiment 3) In Embodiment 3, a light-shielding band and a pellicle made of a water-soluble negative resist are used. The manufacturing process of this mask will be described below. FIGS. 4A to 4F show a method of manufacturing a halftone phase shift mask according to the third embodiment of the present invention. First, as shown in FIG. 4A, a thin film 101 is formed on a quartz glass substrate (blanks) 100, a resist film 102 is further formed thereon, and a normal bake is performed. Drawing (103) was performed using lines. Here, the dimmer thin film 101
Was used as Cr, but this is only an example and, for example, Zr
Si _x O _y film, SiON film, SiN film, CrF _x film, M
oSi _x film, CrO _x F _y film, W film, Ta film, Ti film,
TiN film, WN _x film or the like can be used. The thickness of the Cr film was 22 nm. The thickness of the resist was 155 nm, and PMMA was used as the resist. With this film thickness, a transmittance of 6% having a phase difference of π with respect to light having a wavelength of 193 nm.
Of the halftone film. In order to reduce the phase difference to 3π in which pinhole defects are less likely to occur in wet etching described in Embodiment Mode 1, the resist film thickness may be set to 467 nm. Note that the transmittance of this film to arF excimer laser light having a wavelength of 193 nm is 85%. The phase difference due to the Cr layer is about 0.1 °, and the phase difference 3π is almost caused by this resist layer. Thereafter, as shown in FIG. 4B, development was performed to form a resist pattern 104 on which a circuit pattern 105 and a reticle alignment mark pattern 106 were formed. An opening 117 is also formed in a place where a pellicle frame which will appear in a later step is placed. Then Figure 4
As shown in (c), the Cr film, which is a dimmer, was etched to form a dimmer pattern 107. Although dry etching can be used for this etching, wet etching is performed here.

Thereafter, as shown in FIG. 4D, a water-soluble negative resist 110 is applied, a portion where a light-shielding band is to be formed is exposed, and then development is performed, as shown in FIG. A light shielding band 112 was formed. The water-soluble negative resist used here was prepared by the following method. Acrylamide 6.2
6 g and diacetone acrylamide (6.34 g) were dissolved in ion-exchanged water to make 180 g, which was charged into a 200 ml separable flask and heated to 57 ° C. in a water bath. An aqueous solution of 0.02 g of 2,2′-azobis (2- (imidazolin-2-yl) propane) dihydrochloride was injected into the mixture as a radical polymerization initiator,
The polymerization reaction was carried out for 5 hours in this state. The molecular weight of the obtained copolymer was 1.4 million.

Take 9.40 g of the obtained 7% copolymer,
0.066 g of sodium 4-azidocinnamaldehyde-2-sulfonate, 1.90 g of ion-exchanged water,
After adding 3.6 g of an aqueous sodium hydroxide solution and reacting for 2 days, the mixture was neutralized with glacial acetic acid, and the solid content was adjusted to 1.0 with ion-exchanged water.
Diluted to 5%. In addition to this,
A resist solution was prepared by adding 100% of ethylene glycol and 0.01% of a silane coupling agent. Since it is a negative resist, the exposed portion is limited to a small portion forming a light-shielding band, and the remaining portion is automatically removed by development. Here, a 365-nm laser beam is used as the exposure light, but an electron beam can also be used. Since it was a water-soluble resist, it did not affect the pattern composed of PMMA at all. Thereafter, as shown in FIG. 4F, the pellicle frame 113 on which the pellicle film 114 was formed was adhered to a mask to manufacture a halftone phase shift mask for ArF having a wavelength of 193 nm. Opening 117 in previous process
Is formed, the pellicle frame is directly formed on the glass substrate 100. Thereby, peeling of the pellicle frame 113 can be prevented. Also, pellicle frame 1
When a resist film is formed at the mounting position of No. 13,
When the pellicle 114 is attached or detached, the resist film peels off, which causes the generation of foreign matter. In the third embodiment, since the pellicle frame 113 is joined in a state of being directly in contact with the glass substrate 100, such generation of foreign matters can be prevented.

FIG. 5A is a top view of a halftone phase shift mask manufactured by this method. Glass substrate 10
On 0, a circuit pattern 105, a light shielding band 112, a reticle alignment mark 106, and a pellicle frame 113 are formed. Here, the reticle alignment mark 106 is formed outside the pellicle frame 113, but this positional relationship varies depending on the system of the exposure apparatus, and the reticle alignment mark may be placed inside the pellicle frame 113. FIG. 5B shows a state where the mask is placed on the stage 116 of the exposure apparatus. The halftone film made of the resist and the Cr film was not left at the place 115 which was in contact with the stage of the exposure apparatus, thereby preventing the occurrence of resist peeling foreign matter due to the contact.

Since the thickness of the film to be etched (halftone film) of the mask is extremely thin, about 1/5, the pattern dimensional accuracy of the halftone phase shift mask manufactured according to the present embodiment was extremely high at 9 nm. . In the conventional method, 1
It was 5 nm.

(Embodiment 4) In Embodiment 4, photosensitive SOG and a normal negative resist are used in place of the PMMA resist and the water-soluble negative resist used in Embodiment 3. That is, photosensitive SOG containing silanol containing 5% of an acid generator and a phenolic resin chemically amplified negative resist were used. An electron beam was used for exposure of the light-shielding zone. After forming the photosensitive SOG pattern by development, the SOG pattern was cured by baking at 250 ° C. to make it insoluble in the phenolic resin-based chemically amplified negative resist. In the present embodiment, the film thickness of the film to be etched 101 is significantly thin, about ５ of the film thickness of the film to be etched (halftone film) of a normal halftone phase shift mask. The pattern dimensional accuracy of the obtained halftone phase shift mask was as extremely high as 9 nm. In the conventional method, it was 15 nm. SOG hardened by curing and baking has a feature that it is rich in irradiation resistance, has higher mechanical strength than other photosensitive organic substances, and can be brush-cleaned.
Further, it hardly changes with time, and has a service life of two years or more.

(Embodiment 5) In Embodiment 5, the light-shielding band is formed by a fine pattern. The manufacturing process of this mask will be described below. FIGS. 6A to 6D show a method of manufacturing a halftone phase shift mask according to a fifth embodiment of the present invention. First, as shown in FIG.
After forming a resist film 102 thereon and performing normal baking, a desired pattern was drawn using an electron beam (103). At the time of this exposure 103, a fine pattern described later as shown in FIG.

The decline As the optical thin film 101 with Cr, this is only an example for example ZrSi _x O _y film, Si
ON film, SiN film, CrF _x film, MoSi _x film, CrO
_x F _y film, W film, Ta film, Ti film, TiN film, WN _x film or the like can be used. The thickness of the Cr film is 20.6 nm
And

The film thickness of the resist was 383 nm, and an electron beam photosensitive positive type chemically amplified resist was used as the resist. With this film thickness, a halftone film having a phase difference of 3π with respect to light having a wavelength of 248 nm is obtained.

Thereafter, development is performed as shown in FIG. 6B, and the circuit pattern 105 and the reticle alignment mark pattern 1 are developed.
06, a resist pattern 104 on which a wafer alignment mark 122 and a light shielding band fine pattern 121 were formed. An opening 117 is also formed in a place where a pellicle frame which will appear in a later step is placed.

Thereafter, as shown in FIG. 6C, the Cr film, which is a light reducer, was etched to form a light reducer pattern 107. Although dry etching can be used for this etching, here, wet etching was performed using a cerium nitrate second ammonium aqueous solution.

Thereafter, as shown in FIG. 6D, the pellicle frame 113 on which the pellicle film 114 was formed was pasted on a mask to manufacture a halftone phase shift mask for KrF. The pellicle frame is directly formed on the glass substrate 100 because the opening 117 is formed in the previous step.

Thus, peeling of the pellicle frame 113 can be prevented. Further, if a resist film is formed at the mounting position of the pellicle frame 113, the pellicle 1
At the time of attaching and detaching 14, the resist film is peeled off, which causes the generation of foreign matter. In the fifth embodiment, since the pellicle frame 113 is joined in a state of being in direct contact with the glass substrate 100, such generation of foreign matter can be prevented.

FIG. 7 is a top view of a halftone phase shift mask manufactured by this method. On a glass substrate 100, a circuit pattern 105, a reticle alignment mark 106, a pellicle frame 113, and a light-shielding band 121 are formed. Here, the reticle alignment mark 106 is formed outside the pellicle frame 113, but this positional relationship varies depending on the system of the exposure apparatus, and the reticle alignment mark may be placed inside the pellicle frame 113. A wafer alignment mark 122 is provided in the light shielding zone 121.
Are formed. The wafer alignment mark is a reference mark when performing interlayer alignment. This mark is transferred to the wafer, and a pattern is carved on the wafer by etching or the like, and the mark is detected as a wafer position reference and used as a subsequent alignment reference. This mark is desirably formed in a light-shielding zone having a high light-shielding rate. In the formation of holes that are frequently used in a halftone mask, the body pattern is greatly affected by light diffraction, so that the dose during wafer exposure increases. Since the wafer alignment mark is one digit or more larger than the main body pattern, the appropriate dose is smaller than the main body pattern. Further, if the halftone field allows transmission of light of several percent or more, the size of the subpeak changes due to the influence of lens aberration during wafer exposure, which adversely affects the alignment reference mark such as the left-right symmetry of the pattern is lost. When the wafer alignment mark is formed in the light-shielding zone, the amount of light in the field portion is 0, and thus there is an effect that this adverse effect is reduced.

FIG. 8 is an enlarged top view showing a main part of the light shielding band. The light-shielding band includes the fine opening 124 and the halftone portion 1
23, these patterns are arranged at a fine pitch 125. The fine patterns include a stripe pattern shown in FIG. 8A, a hole pattern shown in FIG. 8B, and a combination of these. In the case of a stripe, a vertical line, a horizontal line, or an oblique line may be used. The pattern repetition pitch 125 is α · λ / NA, and the area ratio S between the aperture pattern 124 and the halftone field pattern 123 is S = β · (T) ^1/2 . Here, λ is the exposure wavelength, NA is the numerical aperture of the projection lens, T is the transmittance of the halftone film, α ≦ 0.8, 0.5
≤β≤2.0. By using this light-shielding band, a sufficient light-shielding rate can be obtained. The method of forming a light-shielding band using the fine pattern has a feature that a wafer alignment mark can be formed in the light-shielding band, and the above-described effect can be obtained. Further, the present mask can be manufactured by using the mask manufacturing equipment conventionally used, and there is a feature that no new capital investment is required.

(Embodiment 6) In this embodiment, scan coating of ink is used as a method of forming a light-shielding band. Here, an ink was used in which iron sulfate, tannic acid, gallic acid, aniline black and hemicellulose were dissolved in water, and a viscosity modifier and a surface tension modifier were mixed. Glycerin was used as the viscosity modifier, but polyethylene glycol and saccharides can also be used. Ethylene glycol was used as the surface tension modifier, but not limited thereto, alkyl benzene sulfonate, dialkyl succinate sulfonate, carboxylate of alkyl ethylene diamine, alkyl betaine-N-alkyl-N, N-dimethyl glycine , P. O. E fatty acid esters, acetylene glycol and the like can also be used. As the dye, an organic substance represented by the following chemical formula (Chemical Formula 1) can also be used. Here, R ₁ to R ₄ represent an OH group or an NH ₂ group. As other dyes, disazo dyes, theofendisazo dyes, trisazo dyes, cyanuric acid dyes and the like can also be used.

[0029]

Embedded image FIG. 9 shows an outline of partial application of ink to the light-shielding band. FIG. 9A shows a method of applying the light-shielding band 152 to the surface of the mask 151. The ink 153 is ejected from the nozzle 156 whose position is controlled by the position control system 157, and forms the ink 153 on the belt while meandering in the direction of the arrow on the mask surface. The ejection of the ink 154 from the nozzle tip 155 is introduced from an ink supply system 159 and is electrically controlled by a control system 158 so that the ejection can be turned on / off. Control system 158
Then, the ink ejection is turned on / off based on the database 160 indicating the application area. The above-described partial coating method can reduce the consumption of ink and reduce the mask manufacturing cost. Note that it is necessary to use a material which does not dissolve the resist which is a photosensitive composition and has a light-shielding property with respect to exposure light as the ink. Here, a water-soluble ink containing a surfactant was used. The method of forming a light-shielding band using the present ink is characterized in that the steps are simple and the time required to form a light-shielding body is short. Typically, a light-shielding band can be formed in 5 minutes or less.

(Embodiment 7) In the seventh embodiment,
A method of finely adjusting the phase angle of the halftone phase shift mask according to the first to third, fifth, and sixth embodiments will be described with reference to FIG. FIG. 10A shows a cross-sectional structure of a main part of a halftone phase shift mask including the glass substrate 100, the dimming thin film pattern 107, and the resist pattern 104 described in the first to sixth embodiments. Is formed thinner than the target film thickness of the phase angle inversion.
That is, assuming that the refractive index (real part) of the attenuator thin film 107 and the resist 104 with respect to the exposure light is n ′, n is n, the film thickness is d ′, d, and the wavelength of the exposure light is λ, d = (λ−2) (N′−1) d ′) / (2 (n−1)) or d = (3λ−2 (n′−1) d ′) / (2 (n−1)) Keep thin.

Thereafter, as shown in FIG. 10 (b), the exposed surface 170 of the glass substrate was dug by etching to adjust it to a desired phase difference. Dry etching can be used for the etching, but wet etching does not reduce the thickness of the resist and the phase angle can be easily adjusted.
Here, the glass substrate was etched using a wet etching solution in which Cr was used as the light reducing film 107, ammonium fluoride was mixed at a volume ratio of 60, and hydrofluoric acid was mixed at a ratio of 1. Also, the dimming pattern 107 and the resist pattern 10
At the stage of FIG. 10 (a) where 4 was formed, the phase difference between the opening, the pattern formed of the light attenuator and the resist was measured, the amount of etching was determined so that the phase was inverted between the two, and etching was performed. By doing so, the phase difference could be driven to the target value (phase inversion state) with high accuracy. In fact, this method could drive the phase difference to an accuracy of ± 1 ° with respect to the target value.

Embodiment 8 Embodiments 1 to 7 above
An example in which pattern exposure was performed using the halftone phase shift mask shown in FIG. FIG. 11 shows an example of the reduced projection exposure apparatus used here. Exposure light emitted from the light source 1501 of the reduction projection exposure apparatus
02, a mask 1507 is irradiated through an illumination shape adjustment aperture 1503, condenser lenses 1504 and 1505, and a mirror 1506. A masking blade 1522 is placed on the mask so that the size of the opening can be adjusted according to the size of the exposure area.
The mask 1507 is placed with the main surface (first main surface) on which the light-shielding pattern is formed facing downward (semiconductor wafer 1509 side). Therefore, the exposure light is emitted from the back surface (second main surface) side of the mask 1507. Thus, the mask pattern drawn on the mask 1507 is projected onto the semiconductor wafer 1509 as a sample substrate via the projection lens 1508. Mask 150
A pellicle 1510 for preventing a pattern transfer failure due to the adhesion of foreign matter is provided on the first main surface 7 in some cases. The mask 1507 is vacuum-adsorbed onto the mask stage 1512 controlled by the mask position control unit 1511 and is aligned by the position detection unit 1513, so that the center of the mask and the optical axis of the projection lens are accurately aligned. . The semiconductor wafer 1509 is placed on the sample stage 15
14 is vacuum-adsorbed. The sample stage 1514 is mounted on a Z stage 1515 movable in the optical axis direction of the projection lens 1508, that is, in the Z axis direction, and further mounted on an XY stage 1516. Z stage 1515
And XY stage 1516 are driven by respective driving means 1518, 1 according to a control command from main control system 1517.
Since it is driven by 519, it can be moved to a desired exposure position. The position is the position of the mirror 1520 fixed to the Z stage 1515,
Is accurately monitored by As the position detecting means 1513, for example, a halogen lamp is used.

The resist on the mask was exposed so as not to leave a resist film on the part of the exposure apparatus that is in contact with the stage or the transport system, thereby preventing the generation of foreign substances caused by transport. Without this treatment, foreign matter was generated and caused transfer defects.

The present mask was mounted on the main exposure apparatus, and step-and-scan exposure was performed to transfer the mask onto the wafer. The reduction ratio of the lens is 4. As a result, no transfer defect occurred, and the dimensional accuracy was improved by about 8 nm as compared with the conventional method. Although exposure is performed through a 4x reduction optical system, the dimensional accuracy improvement of the mask due to the MEF has led to such a large dimensional accuracy improvement. Also, since a light-shielding band is formed on the mask,
No problem occurred in the multiple exposure portion between shots.

Although the invention made by the inventor has been specifically described based on the embodiment, the invention is not limited to the embodiment and can be variously modified without departing from the gist of the invention. Needless to say,

[0036]

According to the present invention, the processing accuracy of the halftone film can be remarkably improved. Further, it has become possible to provide a halftone phase shift mask with high dimensional accuracy at a high yield.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main structure of a halftone phase shifter pattern of a mask of the present invention.

FIG. 2 is a sectional structural view showing a manufacturing process of the mask of the present invention.

FIG. 3 is a top view of the mask of the present invention.

FIG. 4 is a sectional structural view showing a manufacturing process of the mask of the present invention.

FIG. 5A is a top view of the mask of the present invention,
FIG. 4B is an explanatory diagram showing a state when the exposure apparatus is mounted.

FIG. 6 is a sectional structural view showing a manufacturing process of the mask of the present invention.

FIG. 7 is a top view of the mask of the present invention.

FIG. 8 is a main part top view showing the structure of the mask of the present invention.

FIG. 9 is an explanatory diagram illustrating a mask manufacturing process of the present invention. (A) is a top view and (b) is a cross-sectional view.

FIG. 10 is a cross-sectional structural view of a main part showing a manufacturing step of the mask of the present invention.

FIG. 11 is an apparatus conceptual diagram showing an outline of an exposure apparatus used in the present invention.

[Explanation of symbols]

3s ... semiconductor substrate, 6n ... n well, 6p ... p well,
7 ... field insulating film, 8, 9 ... gate insulating film, 1
0 ... nMISQn semiconductor region, 11 ... pMISQp semiconductor region, 12 ... interlayer insulating film, 13L ... wiring, 13
R: resistance, 14: HLD (silicon oxide) film, 15: connection hole, 16L1: first layer wiring, 100: glass substrate,
101: metal-containing film, 102: resist, 103: electron beam, 104: resist pattern, 105: circuit pattern, 1
06: reticle mark, 107: metal-containing film pattern (dimming pattern), 108: laser light, 109: blackened portion (light-shielding band), 110: water-soluble negative resist, 111: exposure light, 112: light-shielding band pattern , 113 pellicle frame, 114 pellicle film, 115 contact portion, 116 reticle stage, 121 light shielding band, 122 wafer alignment mark, 123 halftone pattern, 124 opening pattern, 125 pattern pitch, 151 Mask, 15
3: light-blocking agent (ink), 154: light-blocking agent (ink), 1
55 ... nozzle tip, 156 ... nozzle, 157 ... position control system, 158 ... control system, 159 ... ink supply system, 160 ...
Database, 1501 ... light source, 1502 ... fly-eye lens, 1503 ... illumination shape adjustment aperture, 150
4, 1505: condenser lens, 1506: mirror, 1507: mask 1507, 1508: projection lens, 1509: semiconductor wafer, 1510: pellicle, 1
511: mask position control means, 1512: mask stage, 1513: position detection means, 1514: sample stage, 15
15 ... Z stage 1515, 1516 ... XY stage,
1517: Main control system, 1518, 1519: Driving means, 1520: Mirror, 1521: Laser length measuring device, 15
22 ... Masking blade.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/027 H01L 21/30 502P

Claims (33)

[Claims] 1. A transparent substrate, and a semi-transparent phase shifter pattern formed on the transparent substrate for forming an element pattern, wherein the semi-transparent phase shifter pattern is a light-reducing film and a photosensitive material for phase adjustment. A photomask comprising: a composition film. 2. The method according to claim 1, wherein the thickness of the photosensitive composition film is such that the exposure light transmitted through the transparent substrate in a region where the translucent phase shifter pattern is disposed is in a region where the translucent phase shifter pattern is not disposed. 2. The photomask according to claim 1, wherein a phase of said exposure light transmitted through said transparent substrate is set to be inverted. 3. The photomask according to claim 1, wherein the photosensitive composition film is a photosensitive coated glass film to which an acid generator has been added. 4. The photomask according to claim 1, wherein said dimming film is a film containing a metal. 5. The photomask according to claim 1, wherein a light-shielding band mainly composed of carbon is provided outside the translucent phase shifter pattern. 6. The photomask according to claim 1, wherein a light-shielding band including a negative resist film is provided outside the translucent phase shifter pattern. 7. A semi-transparent shifter region having a plurality of finer openings formed outside said semi-transparent phase shifter pattern, and having a light-shielding band on the surface to be exposed where the intensity of the exposure light is substantially zero. The photomask according to any one of claims 1 to 4, wherein: 8. The photomask according to claim 1, further comprising a light-shielding band formed by using ink outside said translucent phase shifter pattern. 9. The photomask according to claim 5, wherein a wafer alignment mark is formed in the light-shielding band. 10. The photomask according to claim 1, wherein the pellicle frame is directly attached to the transparent substrate with an adhesive. 11. A transparent substrate, provided on the transparent substrate,
A halftone phase shifter pattern comprising a light-attenuating film and a photosensitive composition film for phase adjustment, wherein the thickness of the photosensitive composition film is in a region where the translucent phase shifter pattern is disposed. A photomask, wherein a phase difference of the exposure light transmitted through the transparent substrate in a region where the translucent phase shifter pattern is not disposed with respect to the exposure light transmitted through is set to 3π. 12. The photomask according to claim 11, wherein the light reducing film is a film containing a metal. 13. The photomask according to claim 11, wherein the thickness of the light reducing film is set so that the transmittance of exposure light is in a range of 1 to 25%. 14. A transparent substrate, provided on the transparent substrate,
A halftone phase shift mask, comprising: a halftone phase shifter pattern having a laminated structure including a light reducing film containing a metal and a photosensitive organic film for phase adjustment. 15. The photomask according to claim 14, wherein the light reducing film is a chromium film. 16. The light attenuating film is a ZrSixOy film, a Si
ON film, SiN film, CrFx film, MoSix film, CrO
xFy film, W film, Ta film, Ti film, TiN film or WNx
The photomask according to claim 14, wherein the photomask is a film. 17. The method according to claim 14, wherein the thickness of the light reducing film is set so that the transmittance of the exposure light is in a range of 1 to 25%. Photo mask. 18. A step of preparing a transparent substrate, a step of forming a light reducing film on the transparent substrate, a step of forming a photosensitive composition film for phase adjustment on the light reducing film, Exposing the photosensitive composition film using a line, and then developing the photosensitive composition film to form a photosensitive composition film having a desired shape; and Processing the light attenuating film using a composition film as a mask to obtain a translucent phase shifter pattern having a laminated structure of the light attenuating film and the photosensitive composition film. Method. 19. The method according to claim 18, wherein the light reducing film is a film containing a metal. 20. The method for manufacturing a photomask according to claim 18, wherein a surface of the light reducing film is subjected to a hydrophobic treatment before forming the photosensitive material film. 21. The method for manufacturing a photomask according to claim 18, wherein the processing of the light reducing film is wet etching. 22. The photosensitive material film is a resist film,
The photomask according to any one of claims 18 to 21, further comprising a step of irradiating an infrared laser to a peripheral portion of the translucent phase shifter pattern to carbonize the resist film to form a light-shielding band. Production method. 23. A light-shielding band according to claim 18, wherein a negative resist film is formed on the translucent phase shifter pattern, and the light-shielding band is left by leaving the negative resist film on the periphery of the phase shifter. 3. The method for manufacturing a photomask according to 1. 24. The translucent phase shifter pattern has a peripheral portion formed of a translucent shifter region in which a plurality of fine openings are formed, and has a light-shielding band on the surface to be exposed where the intensity of the exposure light is substantially zero. The method of manufacturing a photomask according to claim 18. 25. Outside the translucent phase shifter pattern,
22. The method for manufacturing a photomask according to claim 18, further comprising a step of forming a light-shielding band using ink. 26. The method according to claim 25, wherein the ink is applied by scanning. 27. The fine adjustment of the phase difference of the exposure light transmitted through the region where the translucent phase shifter pattern is formed and the region where the translucent phase shifter pattern is not formed is dug in the transparent substrate. Item 27. The method for manufacturing a photomask according to any one of Items 18 to 26. 28. The method according to claim 27, wherein the digging of the transparent substrate is performed by wet etching. 29. A step of preparing a transparent substrate, and a step of forming a translucent phase shifter pattern having a laminated structure of a light reducing film and a photosensitive composition film for phase adjustment on the transparent substrate. The thickness of the photosensitive composition film, the exposure light transmitted through the transparent substrate in the region where the translucent phase shifter pattern is disposed, the transparent substrate in the region where the translucent phase shifter pattern is not disposed A method for manufacturing a photomask, wherein a phase difference of the transmitted exposure light is set to be 3π. 30. A method comprising the steps of: preparing a transparent substrate; and forming a translucent phase shifter pattern having a laminated structure of a light-reducing film and a photosensitive organic film for phase adjustment on the transparent substrate. A method for manufacturing a photomask, which is a feature. 31. The method according to claim 30, wherein the photosensitive organic film is a chemically amplified electron beam resist film. 32. A translucent phase shifter pattern having a laminated structure of a step of preparing a transparent substrate, and a photosensitive coating glass film for phase adjustment before addition of a light reducing film and an acid generator is formed on the transparent substrate. A method of manufacturing a photomask. 33. The method according to claim 32, wherein after the formation of the photosensitive coated glass, a curing bake is performed.