TWI584058B - Large-size phase shift mask and producing method of same - Google Patents

Description

Large phase shift mask and method for manufacturing large phase shift mask

The present invention relates to a photomask, and more particularly to a method for manufacturing a large-sized photomask and a large-sized photomask which can be used for manufacturing an active matrix display device such as a liquid crystal display device or an electroluminescence display device (EL).

The specification change of the reticle for the flat panel display (referred to as FPD (Flat Panel Display)) is a large screen and high definition which is common in a thin type television using a liquid crystal display device (abbreviated as LCD (Liquid Crystal Display)). to represent. With regard to the large screen, the liquid crystal thin TV began mass production, and the size of the glass substrate called the first generation used in the manufacturing at that time in 1990 was 300 mm × 400 mm, and the fifth generation glass that was used for manufacturing around 2002 The size of the substrate is 1100 mm × 1300 mm, and the size of the glass substrate of the 8th generation which was used for manufacturing around 2006 is 2140 mm × 2460 mm.

The high-definition of the liquid crystal display device has been continuously promoting high pixelation in displays for personal computers. The VGA (Video Graphics Array) display is 640 × 480 pixels, the Extended Graphics Array (XGA) display is 1024 × 768 pixels, and the Super Extended Graphics Array (SXGA) display is 1280 × The 1024-pixel, Ultra Extended Graphics Array (UXGA) display is 1600 x 1200 pixels. With such high pixelation, the pixel pitch is also from 0.33 mm to 0.24 mm, 0.20 mm Continuously refine. Furthermore, the smart phone and the like are type 14.5 x 720 pixels, and the pixel pitch is more than 0.077 mm (329 ppi). Further, a high-definition television (HDTV) (High Definition TeleVision) is a display of 1920×1080 pixels, and a pixel of 3840×2160 pixels (referred to as a 4K liquid crystal panel) having four times the number of pixels.

Hereinafter, an exposure apparatus for manufacturing the liquid crystal display device as described above and a photomask for the exposure apparatus will be described. A unit of a thin film transistor (TFT) liquid crystal display device as a representative liquid crystal display device is assembled by sealing liquid crystal between a separately manufactured color filter and a TFT array substrate. Further, in the liquid crystal display unit, a peripheral driving circuit and a backlight which supply a driving signal for converting a video signal into a TFT are assembled, thereby completing the liquid crystal display module.

The TFT array substrate is a substrate in which a plurality of TFTs are arranged in a matrix and the display (ON) and non-display (OFF) of each pixel of the liquid crystal are controlled. As an example, the production is carried out by the following procedure. That is, a step of forming a gate portion of a gate electrode material such as MoW by patterning 1) on a glass substrate; 2) a semiconductor portion forming step of forming an A-Si film in an island shape after forming a gate insulating film; 3) a transparent display electrode forming step of patterning an indium tin oxide (ITO) film; 4) a step of forming a contact hole on the gate insulating film; 5) patterning a conductor layer such as Al, and forming a source of the TFT A step of manufacturing a TFT array substrate by a step of forming a step of forming an insulating protective film on the surface, and a step of forming a step of forming an insulating protective film on the surface.

The pattern for each step of the above-described TFT array substrate manufacturing step is formed by using a double-size large-sized mask having a magnification of 1 to 1, and being exposed by an equal magnification projection type exposure apparatus (also referred to as a projection exposure apparatus). At present, the equal-projection exposure method using the large mask has become a standard manufacturing method for forming a TFT array substrate with good productivity and high precision. Further, in the pattern formation of the color filter, the proximity exposure method which is advantageous in terms of cost is a standard manufacturing method. The proximity exposure system is configured such that the mask and the exposure object are placed close to each other with a gap of several tens of μm to 100 μm, and the exposure mode of the parallel light is irradiated from the mask.

The large-sized mask for the TFT array substrate was originally designed to have a size of 350 mm × 350 mm, but has been continuously enlarged in size as the size of the projection type exposure apparatus used for the manufacture of the TFT array substrate has increased. In a projection type exposure apparatus for a TFT array substrate manufacturing, in order to project a mask pattern onto a workpiece, there is a mirror projection exposure method using a mirror system and a lens projection exposure method using a lens system. 2 kinds. The size of the large mask used varies depending on the specifications of each exposure device. For the 5th generation glass substrate, the mirror projection exposure method uses a large mask of 520 mm × 610 mm size, and the lens projection exposure method uses 800 mm. Large cover of size 920 mm. Further, for the glass substrate of the eighth generation, the mirror projection exposure method uses a large mask of a size of 850 mm × 1400 mm, and the lens projection exposure method uses a large mask of a size of 1220 mm × 1400 mm.

The length of the diagonal of a conventional semiconductor mask (6-inch mask) is about 154 mm. In contrast, the length of the diagonal of the large mask is 495 mm at the time, the fifth Instead, the mirror projection exposure method is about 801 mm, and the 8th generation lens projection exposure method is larger to 1856 mm with a large mask.

As described above, the large mask for pattern formation of the TFT array substrate is a size of 3.2 to 12 times the length ratio of the diagonal with respect to the mask for the semiconductor wafer. Further, the area ratio directly related to the manufacturing cost (filming time, inspection time, and the like) is 10 to 144 times. In terms of the cost requirements of such a large size, the layer of the large mask is composed of a light-shielding film mainly composed of chromium laminated on quartz glass, and chromium oxide or chromium oxynitride laminated on the light-shielding film. It is composed of two layers of an antireflection film as a main component. It is preferable that the light-shielding film has a transmittance of 0.1% or less in the exposure wavelength to be used, and it is preferable that the anti-reflection film has a reflectance of 30% or less in the exposure wavelength used.

As described above, the TFT array substrate is enlarged on the one hand, and on the other hand, the pattern is required to be miniaturized in recent years. That is, it is necessary to uniformly image the fine pattern close to the resolution limit of the exposure device or the fine pattern close to the resolution limit of the exposure device in the entire exposure region.

If a binary mask having a fine line and gap (L/S) pattern below the resolution limit of the exposure device is used, the photoresist is exposed, and on the imaging surface, corresponds to the line on the mask (shading The amplitude of the exposure intensity of the portion of the gap and the transmission (transmission) becomes small, and the partial exposure corresponding to the gap (transmission) portion is not reached. The threshold of the sensitivity of the resist, eventually, even if the photoresist is developed, the pattern cannot be formed.

A method of using a gray scale mask is proposed in Patent Document 1 (Japanese Laid-Open Patent Publication No. 2009-42753), which is a method of the prior art. FIG. 4 of FIG. 1 disclosed in Patent Document 1 and FIG. 5 schematically showing the exposure light amount distribution in addition to FIG. 4 will be described.

As shown in FIG. 4(a), the photomask 50 exemplified in the prior art is formed on the transparent substrate 51 with four regions: a light shielding portion 54 of the light shielding film 52 having no fine pattern, and a half having no fine pattern. The semi-transmissive portion 55 of the light transmissive film 53, the fine pattern portion 56 of the semi-transmissive film 53 (consisting of the translucent portion and the semi-transmissive portion of the semi-transmissive film 53), and the light transmitting portion 57 (exposing the transparent substrate 51) ).

When the exposure light beam 40 is used, the photomask 50 exemplified in the above-described prior art is exposed, and the pattern is transferred to the photoresist film (positive photoresist) 63 on the transfer target 60, as shown in FIG. 4 (b). In the transfer body 60, a residual film region 63a including a thick film after development, a residual film region 63b of the film, a fine pattern region 63c corresponding to the fine pattern portion 56 on the mask 50, and There is substantially no transfer pattern (resist pattern) of the region 63d of the residual film. Further, reference numerals 62a and 62b in Fig. 4 denote films laminated on the substrate 61 in the transfer target 60.

The effect of the fine pattern 56 of the semi-transmissive film is shown in Fig. 5 for explanation. That is, a fine pattern is formed by a light shielding film in a manner of a normal binary mask. In the case of the distribution light amount 74c of the exposure light amount (Fig. 5(b)), even if the peak portion corresponding to the exposure amount of the light transmitting portion does not reach the exposure amount 75 of the positive photoresist removal, the pattern cannot be formed. On the other hand, when the fine pattern 56 of the semi-transmissive film is subjected to exposure transfer using the photomask 50 (FIG. 5(a)), the transmission amount of the exposure beam is larger than that obtained by using the ordinary binary mask. The amount of transmission of the amount of exposure light in the fine pattern portion. The distribution shape 73c of the exposure light amount when the fine pattern is formed by the semi-transmissive film is such that the peak portion of the exposure amount of the light-transmitting portion reaches the exposure amount 75 of the positive-type photoresist removal, thereby obtaining a sufficient amount of exposure even for the fine pattern, thereby A pattern 63c is formed on the photoresist.

On the other hand, when the fine pattern 56 of the semi-transmissive film 53 is transferred by exposure using the mask 50 of the prior art, the amount of transmission of the exposure beam is larger than that of the mask using the ordinary binary mask. The amount of transmission of the amount of exposure light in the pattern portion causes the contrast of the exposure light amount distribution to decrease. Therefore, when the fine pattern portion 56 of the semi-transmissive film is transferred, the photoresist residual film value of the fine pattern region 63c on the transfer target is smaller than when the ordinary light-shielding film pattern is transferred (for example, the thick film residual film region 63a). Photoresist residual film value. (Although the positive type resist is taken as an example, it is the same in the case of a negative type resist.) In this case, the exposure amount is adjusted in order to appropriately perform the etching process of the subsequent transfer body. And in the developing process of the exposed photoresist, it is necessary to appropriately adjust the conditions, thereby preferably adjusting the residual film value of the photoresist.

[Previous Technical Literature] [Patent Literature]

Patent Document 1: Japanese Patent Laid-Open Publication No. 2009-42753

As described above, the reticle for the manufacture of a flat panel display represented by a liquid crystal display device is being continuously developed. On the other hand, the miniaturization of the display pixel pitch of the flat panel display is progressing, and the transfer pattern of the reticle is miniaturized. The requirements are also growing.

Therefore, as a mask for replacing a conventional binary mask, a phase shift film having a transparent substrate and a pattern formed on a transparent substrate is used, and a region where the transparent substrate is exposed is used as a transmissive region, and a phase shift film is formed. The region acts as a phase shift mask of the phase shift region. The phase shift mask can suppress the diffusion of the light intensity by arranging the phase shift region at a position where the light amplitude of the diffused portion of the light amplitude distribution of the transmission region due to the analysis limit is canceled, thereby exposing the finer pattern .

However, the phase shift film system generally has a light-shielding ability lower than that of the light-shielding film of the binary mask, and becomes a translucent film. Therefore, when the above-described phase shift mask is used for exposure, it corresponds to the above. The portion of the boundary between the transmissive region and the phase-shifting region has less diffusion of the pattern of the photoresist, so that the side surface thereof has a steep shape, but the portion corresponding to the central portion of the phase-shift region is transmitted by the phase-shifting film itself. The rate affects the problem of dents on the photoresist. Further, although the photoresist having the above-described recess can function to protect the lower layer, in the inspection performed after the development step of the photoresist, there is the above-described The depressed photoresist is detected as a defect. Therefore, since the photoresist having the protective function is also judged to be defective by the detection, it is unusable, and there is a problem that the productivity of the TFT array substrate or the like is lowered.

It is an object of the present invention to provide a phase shift mask which is suitable for use in a configuration of a large reticle and a method of manufacturing the same, wherein the phase shift mask is used to transfer a pattern to a transfer target by exposure to enhance imaging The contrast of the exposure light amount distribution of the fine pattern on the surface is transferred. Furthermore, in the present case, a mask having a length of 350 mm or more on one side is used as a large-sized mask.

(1st means)

A first aspect of the present invention is a large phase shift mask comprising a transparent substrate, a light shielding film formed on the transparent substrate, and a translucent phase shift film formed on the transparent substrate. The phase shift mask includes: a transmissive region exposing the transparent substrate; a light-shielding region in which the light-shielding film is provided on the transparent substrate; and a phase shift region in which the phase shift film is provided on the transparent substrate And a pattern in which the transmissive region is adjacent to the phase shift region, and a phase shift region is disposed adjacent to the transmissive region and the light-shielding region, and the exposure beam transmitted through the phase shift region is opposite to the transmissive region The phase of the exposure beam is reversed; the light-shielding film is mainly composed of chromium or a chromium compound, and the phase-shift film is mainly composed of chromium oxide or chromium oxynitride, and the light-shielding film is formed in the light-shielding region. There is a phase shift film on the upper layer.

By using the large phase shift mask of the first means described above, the contrast of the exposure pattern can be raised for the fine pattern in a large area, and the existing large-sized hard mask blank can be used as a starting material for manufacturing, and the large size can be reduced. The manufacturing cost of the phase shift mask.

(2nd means)

A second aspect of the present invention is the large phase shift mask according to the first aspect, further comprising an antireflection film between the light shielding film and the phase shift film in the light shielding region.

According to the second means, it is possible to prevent surface reflection of the light-shielding region of the large phase shift mask, thereby preventing stray light from being caused during exposure and causing a decrease in transfer precision.

(3rd means)

The third aspect of the present invention is the large phase shift mask according to any one of the first aspect or the second aspect, wherein the phase shift region has a width in a range of 0.25 μm or more and 3.5 μm or less.

According to the third means, the effect of increasing the phase shift of the contrast of the exposure pattern can be favorably obtained.

(4th means)

The fourth aspect of the present invention is the large phase shift mask according to any one of the first to third aspect, wherein the width of the narrowest portion of the transmissive region is a width in a range of 1 μm or more and 6 μm or less.

According to the fourth means, the contrast of the exposure pattern can be well obtained. The effect of displacement.

(5th means)

The fifth aspect of the invention is the large phase shift mask according to any one of the first to fourth aspect, wherein the phase shift film of the exposure light beam has a light transmittance of 4% or more and 15% or less.

According to the fifth means, the effect of increasing the phase shift of the contrast of the exposure pattern can be favorably obtained.

(6th means)

A sixth aspect of the present invention provides a method of manufacturing a large phase shift mask, which is characterized in that: a phase shift mask comprising: a transparent substrate, a light shielding film formed on the transparent substrate, and a formation a translucent phase shift film on the transparent substrate; and a light-shielding region in which the transparent region is exposed, a light-shielding region in which the light-shielding film is provided on the transparent substrate, and only the phase shift is provided on the transparent substrate a phase shift region of the film; and a pattern in which the transmissive region is adjacent to the phase shift region, and a phase shift region is disposed adjacent to the transmissive region and the light shielding region, and the exposure beam transmitted through the phase shift region is relatively The phase inversion of the exposure beam transmitted through the transmission region is characterized in that the method comprises the steps of: coating a photoresist having a light-shielding film made of a chromium or chromium compound on one surface of the transparent substrate with a photosensitive photoresist; a step of preparing a blank with a photosensitive photoresist; using a drawing device on a blank with a photosensitive photoresist Set the desired pattern After exposure and development, wet etching is performed to remove the photosensitive photoresist to form a light-shielding film; and the transparent substrate and the patterned light-shielding film are formed to form a phase shift film containing a chromium compound. a step of applying a photosensitive photoresist to the formed phase shift film, exposing and developing a desired pattern by using a drawing device, performing wet etching, removing the photosensitive photoresist, and patterning the phase shift film A step of.

According to the sixth aspect of the present invention, a large hard mask blank of chromium can be used as a starting material for manufacturing, and further, patterning of the phase shift film can be performed by wet etching, thereby suppressing the manufacturing cost of the large phase shift mask. The effect is greater.

(7th means)

A seventh aspect of the present invention provides a method of manufacturing a large phase shift mask, which is characterized in that: a phase shift mask comprising: a transparent substrate, a light shielding film formed on the transparent substrate, and a formation a translucent phase shift film on the transparent substrate; and a light-shielding region in which the transparent region is exposed, a light-shielding region in which the light-shielding film is provided on the transparent substrate, and only the phase shift is provided on the transparent substrate a phase shift region of the film; and a pattern in which the transmissive region is adjacent to the phase shift region, and a phase shift region is disposed adjacent to the transmissive region and the light shielding region, and the exposure beam transmitted through the phase shift region is relatively The phase of the exposure beam transmitted through the transmission region is reversed, and the light shielding is performed on the light shielding region The phase shifting film is laminated on the film, and the antireflection film is further disposed between the light shielding film and the phase shift film in the light shielding region; and the method includes the following steps: sequentially laminating one surface of the transparent substrate A light-shielding film containing chromium as a main component, and a photoresist of an anti-reflection film mainly composed of chromium oxide or chromium nitrogen oxide as a main component are coated with a photosensitive photoresist to prepare a blank with a photosensitive photoresist. a step of: exposing and developing a desired pattern on a blank provided with a photosensitive photoresist by wet etching, removing the photosensitive photoresist, and patterning the light-shielding film and the anti-reflection film a step of forming a phase shift film containing a chromium compound on the transparent substrate and the patterned light-shielding film and the anti-reflection film; and applying a photosensitive photoresist to the formed phase shift film. After the drawing device exposes and develops the desired pattern, wet etching is performed to remove the photosensitive photoresist to pattern the phase shift film.

According to the seventh aspect of the present invention, a large-sized hard mask blank having two layers of chromium having an anti-reflection film can be used as a starting material for production, and further, patterning of the phase-shift film can be performed by wet etching, thereby suppressing The large phase shift mask with anti-reflection film has a large manufacturing cost effect.

The contrast of the exposure pattern can be enhanced for the fine pattern in a large area by using the large phase shift mask of the present invention. Further, cover can be used The light film is a conventional large-sized hard mask blank using a film containing chromium as a main component, and as a starting material for manufacturing, a large phase shift mask can be manufactured at low cost.

Hereinafter, embodiments of the large phase shift mask of the present invention and an embodiment thereof will be described with reference to the drawings.

Fig. 1(a) is a cross-sectional view schematically showing the structure of an embodiment of a large phase shift mask of the present invention. Fig. 1(b) and Fig. 1(c) are graphs showing the amplitude and intensity of an exposure beam transmitted through a large phase shift mask on an image plane. 2(a) to (f) are views showing the manufacturing steps of the large phase shift mask of the present invention.

(Composition of large phase shift masks)

As shown in FIG. 1(a), the large phase shift mask 1 of the present invention is configured as a phase shift mask including a transparent substrate 2, a light shielding film 3 formed on the transparent substrate 2, and a transparent layer formed thereon. The translucent phase shift film 5 on the substrate 2 includes a transmissive region 6 exposing the transparent substrate 2, a light-shielding region 7 on which the light-shielding film 3 is disposed on the transparent substrate 2, and only a transparent region 2 on the transparent substrate 2 The phase shift region 8 of the phase shift film 5 includes a pattern in which the transmissive region 6 is adjacent to the phase shift region 8 , and a phase shift region 8 is disposed adjacent to the transmissive region 6 and the light shielding region 7 . And the exposure beam transmitted through the phase shift region 8 is inverted with respect to the phase of the exposure beam transmitted through the transmission region 6.

The light-shielding film 3 is mainly composed of chromium, and the phase-shift film 5 is mainly composed of chromium oxynitride or chromium oxide, and is accumulated on the light-shielding film 3 of the light-shielding region 7. The layer has a phase shifting film 5. Here, the large phase shift mask means a mask having a length of at least 350 mm or more on one side thereof.

A brief description of the effect on the image plane of the edge-enhanced phase shift mask is given. Fig. 1(b) shows the amplitude distribution of light on the imaging surface (specifically, the photosensitive photoresist surface) of the large phase shift mask, and Fig. 1(c) shows the light on the imaging surface of the large phase shift mask. The intensity distribution. The intensity of the light is obtained by squaring the amplitude of the light, and the intensity of the light (same as energy) shows only a positive value with respect to the amplitude of the light as its phase becomes positive and negative. Further, as shown in FIG. 1(a), the exposure light beam 40 is irradiated from the transparent substrate 2 side in the direction of the light shielding film 3. As the exposure beam 40, it can be from the g-line (wavelength 436 nm), h-line (wavelength 405 nm), i-line (wavelength 365 nm), KrF excimer laser (wavelength 248 nm), and KrF excimer of ultra-high pressure mercury lamp. Laser (193 nm) is selected for use. In practical terms, the pattern of the TFT array substrate is formed into a large area, and a large amount of light is required for exposure. Therefore, two wavelengths including a single i-line, an h-line, and an i-line, or three wavelengths of a g-line, an h-line, and an i-line can be used. Exposure beam.

The exposure beam 40 is transmitted through the transmission region 6 of the large phase shift mask 1, and the optical amplitude distribution when imaged on the imaging surface on the photoresist is shown by the dotted line 10 in FIG. 1(b), and the light intensity distribution is shown in the figure. The dotted line 13 of 1(c). If there is no analysis limit, the optical amplitude distribution should be rectangular on the imaging surface, but the optical amplitude distribution having the bell-shaped diffusion is caused by the analysis limit of the exposure device (not shown). On the other hand, the phase of the exposure beam transmitted through the phase shift region of FIG. 1(a) is reversed, and as shown by a broken line 11 in FIG. 1(b), it becomes a negative light amplitude distribution. Such as In the negative light amplitude distribution 11, the phase shift region 8 is disposed at a position where the optical amplitude of the diffused portion of the optical amplitude distribution 10 of the transmissive region 6 is canceled, and the phase shift light is added to prevent the amplitude distribution of the exposure beam from diffusing. The amplitude distribution is shown by the solid line 12 of Fig. 1(b). Further, the intensity distribution of the light including the phase-shifted light corresponding to the amplitude distribution 12 of the light to which the phase-shifted light is added is shown on the solid line 14 of Fig. 1(c). When the light intensity distribution 13 of only the transmission region is compared with the intensity distribution 14 of the light including the phase-shifted light, the light intensity is lowered corresponding to the position of the phase shift region 8, and the diffusion of the light intensity is suppressed. The portion where the light intensity is lowered is indicated by the hatched portion 15. On the other hand, on the outer side of the decrease in the light intensity, a portion in which the light intensity called the side peak is re-energized appears (Fig. 1 (c) 16). If the transmittance of the phase shift region is raised, the side peak becomes strong, but the photoresist must be suppressed to the extent that it is not sensitive.

The optical characteristics required in the phase shift film 5 used in the present invention will be described. The phase shift film 5 is required to invert the film thickness of the exposure beam 40, and the film thickness d of the phase shift film, the refractive index n of the phase shift film, the wavelength λ of the exposure beam, and the exposure beam pass through the phase shift film. Phase difference Between =2π(n-1)d/λ, phase difference reversal = π, so the film thickness d in which the phase difference is reversed becomes λ/2 (n-1). Specifically, if the exposure beam wavelength λ is 365 nm of the i-line and the refractive index n of the phase shift film is 2.55, the thickness of the phase shift film can be calculated to be 118 nm. The allowable range of the variation of the thickness of the phase shift film is within a range of about plus or minus 10% with respect to the thickness of the calculated phase shift film, and if it is within the allowable range, a sufficient phase shift can be obtained as the phase shift film. effect.

When the exposure beam contains a plurality of peak wavelengths (having three bright line spectra) as in the case of an ultrahigh pressure mercury lamp, the film thickness of the phase shift film for each peak wavelength is calculated, and the exposure beam is divided by the respective peak wavelengths. The sum of the energy intensity ratios is weighted (referred to as the weighted average) to determine the film thickness of the phase shift film. For example, when a light source having a g line of Pg, a line of h with a h line, and an energy intensity of an i line having an energy of Pi is used as an exposure light source, if the thickness of each phase shift film corresponding to the g line is Dg, corresponding to the h line The thickness of the phase shift film is Dh, and the thickness of the phase shift film corresponding to the i line is Di, and the thickness D of the phase shift film obtained by weighted averaging is found as D = (Pg × Dg + Ph × Dh + Pi × Di) ÷ (Pg+Ph+Pi). Specifically, when Pg=2, Dg=141 nm, Ph=1, Dh=130, Pi=3, and Di=118 nm, the thickness D of the phase shift film obtained by the weighted average was found to be 128 nm. By using such a thickness D of the phase shift film obtained by weighted averaging, even an exposure beam containing a plurality of peak wavelengths satisfactorily obtains the effect of the phase shift mask.

As a method of determining the thickness D of the phase shift film by weighted averaging, a value obtained by multiplying the energy intensity of the exposure beam with respect to each peak wavelength by the sensitivity of the photoresist of the corresponding wavelength may be used as the weighted average. The method of weighting, in order to get better results.

The light transmittance of the phase shift film 5 is set to a value in which the contrast of the exposed pattern becomes high in the range of the side peak of the effect of not causing the phase shift. Specifically In other words, the light transmittance in the exposure beam of the phase shift film 5 is preferably 4% or more and 15% or less. If the transmittance of the phase shift film is 4% or less, the effect of enhancing the contrast of the phase shift is small. If the transmittance of the phase shift film is 15% or more, the effect of the phase shift is too strong, and the neutron peak in the light-shielding region ( The side peaks become higher, creating the possibility of defects.

As described above, with reference to the cross-sectional view of Fig. 1(a), the regions of the large phase shift mask 1 of the present invention having the effect of suppressing the diffusion of the exposure intensity distribution caused by the resolution limit of the exposure device are faced. The specific dimensions are explained. Furthermore, Fig. 1 illustrates an edge-enhanced phase shift mask.

Fig. 1(a) is a cross-sectional view showing a phase shift mask for exposing a gap pattern of a positive photoresist exposure line and a gap, or a hole pattern. The main use of the large phase shift mask of the present invention is for patterning a TFT array substrate of a flat display panel such as a liquid crystal display device or an EL display device. The analysis limit of the large projection type exposure apparatus used for the pattern formation is about 3 μm, and the large phase shift mask of the present invention has a problem of improving the contrast of the exposure pattern by drawing a pattern with respect to the above analysis limit (3 μm). Therefore, the width a of the transmission region in which the large phase shift mask of the present application exerts a remarkable effect is 1 μm or more and 6 μm or less.

When the width a of the transmission region is larger than 6 μm, the influence of the resolution limit of the exposure device is small, so the effect of the large phase shift mask of the present invention is not remarkable. Further, in the case where the width of the transmission region is less than 1 μm, the exposure pattern cannot be resolved even if the effect of the phase shift of the present invention is added. this Wherein, if the width a of the transmission region is the diameter of the largest inscribed circle as the shape of the transmission region of the object on the plane of the transparent substrate, and if the shape of the transmission region of the object is rectangular, the length of the short side is the width of the transmission region.

The width of the phase shift region in the present invention is not particularly limited as long as it can suppress the diffusion of the light intensity in the transmission region and expose the photoresist to a desired pattern shape.

The width of the phase shifting region is 3.5 μm or less, preferably 2.5 μm or less, and particularly preferably 2.0 μm or less. The reason for this is that when the width of the phase shift region exceeds the above value, there is a possibility that the effect of the phase shift is deviated, and the effect of enhancing the contrast of the exposure pattern is limited. Further, the reason is that the influence of the light amplitude distribution remaining in the phase shift region between the transmissive region and the light-shielding region and the light amplitude of the transmissive region on the peak (side peak) of the light intensity distribution is increased. The photoresist reacts with the transmitted light in the transmission phase shift region, and a depression or the like is formed in the pattern shape of the photoresist, so that it is difficult to make the pattern shape of the photoresist into a desired shape.

Further, in the present invention, since the phase shift region is provided, the diffusion of the light intensity in the transmissive region can be suppressed. Therefore, as for the lower limit of the width of the phase shift region, if the phase shift film can be formed, there is no It is particularly limited to 0.25 μm or more, and preferably 0.5 μm or more, and particularly preferably 0.8 μm or more. The reason for this is that the phase shift region can be set with good alignment accuracy. Moreover, the reason is that when the above value is not satisfied, the amount of light having a phase inversion is reduced. The possibility of less effect.

Further, the width b of the phase shift region is in the range of 0.5 μm or more and 2 μm or less, and the effect of the phase shift is most remarkable.

Here, the width b of the phase shift region is the shortest distance obtained by measuring the distance from the boundary between the transmissive region and the phase shift region to the boundary between the phase shift region and the light-shielding region in parallel with the surface of the transparent substrate.

Here, the resolution limit of the large projection type exposure apparatus described above is the width of the transmission area of the binary mask which can be stably analyzed in the exposure region when the exposure is performed by the binary mask in the large projection type exposure apparatus. The minimum value (hereinafter, sometimes referred to as the width of the resolution limit) is handled equally.

When the phase shift mask of the present invention is used together with a large projection type exposure apparatus, the drawing pattern below the width of the resolution limit of the binary mask can be analyzed.

The width of the drawing pattern of the phase shift mask of the present invention is 100% or less with respect to the resolution limit of the binary mask in the large projection type exposure apparatus, and preferably 85% or less and 30% or more. Among them, it is preferably 40% or more. This is because when the width of the above-described drawing pattern does not satisfy the above range, there is a possibility that it is difficult to analyze the drawing pattern itself. Further, the reason is that when the width of the drawing pattern exceeds the above range, there is a possibility that it is difficult to sufficiently exhibit the effect of phase shift. When the width of the drawing pattern in the phase shift mask is the same as the width of the resolution limit, the shape of the photoresist can be made larger than when the binary mask is used for exposure. good.

For the width of the above-mentioned drawing pattern, the width and phase shift region of the transmission region of the phase shift mask of the present invention can be adjusted by the width of the resolution limit inherent in the large projection type exposure apparatus and the sensitivity of the photoresist. The width, the transmittance of the phase shift film, and the like are determined.

Here, as shown in FIG. 3(b), the width d of the transmissive region of the binary mask is measured parallel to the surface of the transparent substrate from one of the light-shielding regions adjacent to one of the transmissive regions to another boundary. The shortest distance from the distance.

Moreover, the width of the drawing pattern of the phase shift mask refers to the width of the pattern drawn on the photoresist by the transmissive region and the phase shift region.

(embodiment)

(Composition material of large phase shift mask)

Referring to the cross-sectional view of Fig. 1(a), a specific material of each constituent element of the large phase shift mask 1 of the present invention will be described. The large phase shift mask 1 shown in FIG. 1(a) includes a transparent substrate 2, a light shielding film 3 formed on the transparent substrate 2, and a translucent phase shift film 4 formed on the transparent substrate 2. The constructed reticle.

The transparent substrate 2 used in the large phase shift mask 1 of the present invention has a size of 350 mm × 350 mm to 1220 mm × 1400 mm and a thickness of 8 mm to 13 mm. As the material, an optically polished low-expansion glass (aluminum borosilicate glass, borosilicate glass) or synthetic quartz glass can be used, but a synthetic quartz glass having a small thermal expansion coefficient and a high ultraviolet transmittance is preferably used.

The light-shielding film 3 used in the present invention is required to have a transmittance of 0.1% or less at an exposure wavelength and which is easy to pattern. As a material of such a light-shielding film, chromium, a chromium compound, a molybdenum molybdenum compound, or a ruthenium compound can be used, and it is preferable to form a good pattern in wet etching and to use a chromium or chromium compound having a large amount of actual performance. A light-shielding film of ingredients. As the chromium compound, chromium nitride having a high light-shielding property and a thin film thickness of the light-shielding film can be used. When the chrome-shielding film is compared with the chrome-plated ray-shielding film, it is preferable to use a varnish film which is easy to form and has high versatility, and is easy to obtain. Specifically, when a metal chromium thin film is used as a light-shielding film, since the transmittance of the exposure light beam is 0.1% or less, the film thickness is 70 nm or more. On the other hand, when the film thickness is increased, the etching time is increased and the workability is lowered. Therefore, a film thickness of 150 nm or less is usually used.

The phase shift film 5 used in the present invention is required to have a transmittance in the range of 4% to 15% in the exposure wavelength and which is easy to pattern.

As the material of the phase shift film 5, it can be selected from materials which are translucent and have a suitable refractive index, and chromium oxynitride (CrON), chromium oxide (CrO), bismuth molybdenum oxide (MoSiO), bismuth oxynitride (MoSiON) can be used. ), cerium oxide (TaSiO), or titanium oxynitride (TiON). If an oxide or an oxynitride constituting the material of the light shielding film 3 is selected as the material of the phase shift film 5 among the materials, the advantages of using the same etching apparatus and steps to form a phase shift film and a light shielding film can be obtained. .

Further, chromium or chromium nitride is selected as the light shielding film 3, and chromium oxide (CrO) is selected. Or chromium oxynitride (CrON) as the phase shift film 5, whereby not only the same etching apparatus can be used, but also the light shielding film 3 and the phase shift film 5 can be processed, and the cerium (IV) nitrate system having good pattern processability can be used. The wet etchant wet-etches both the light-shielding film 3 and the phase shift film 5, and has a large cost advantage.

Here, in the conventional large projection type exposure apparatus, it is difficult to irradiate only the parallel light as the exposure light beam, and it is often the case that light having a predetermined angle is included in one of the exposure light beams. Further, light that is diffracted in the edge of the pattern, or reflected light at the junction of the film or the like appears as stray light. Moreover, such stray light is different in the irradiation position in the large projection type exposure apparatus from the position where the photoresist is actually reached, so that there is a photoresist corresponding to the light-shielding area of the phase shift mask which is not required to be exposed. After exposure.

Further, in the present invention, the light-shielding region has a structure in which a light-shielding film is laminated on a transparent substrate, and a phase-shift film is laminated on the light-shielding film. Further, the phase shift film has a thickness D of a phase difference π. Therefore, it is considered that the stray light exhibits the following behavior when, for example, a pattern for forming a TFT array substrate or the like is patterned by using the phase shift mask of the present invention. First, the stray light that has been irradiated from the large projection type exposure apparatus is transmitted through the transparent substrate of the phase shift mask, and is reflected by the metal electrode or the like of the TFT array substrate to become reflected light. Next, the reflected light of the stray light is incident on the phase shift film of the light-shielding region, is reflected by the light-shielding film, becomes the second reflected light, and is emitted again from the phase shift film. Therefore, the reflected light of the stray light incident on the phase shift film of the light-shielding region and the second reflection of the stray light emitted from the phase shift layer by the light-shielding film The phase difference of the light becomes 2π. Therefore, since the reflected light and the second reflected light are mutually reinforced on the surface of the phase shift film, the influence of stray light on the photoresist becomes more remarkable.

The above problems are caused by the layer constitution of the light-shielding region in the present invention.

In the present invention, it is expected that the light-shielding region has an anti-reflection function from the viewpoint of measures against stray light during exposure. The light-shielding region 7 used in the present invention has a structure in which a light-shielding film 3 is laminated on the transparent substrate 2 and a phase shift film 5 is laminated on the light-shielding film 3, but the phase shift film 5 has a thickness D of a phase difference π, and The exposure light beam (the second reflected light of the stray light) reflected on the surface of the light shielding film 3 and the reflected light (the reflected light of the stray light) on the surface of the phase shift film 5 have a phase difference of 2π and are mutually reinforced. In order to alleviate this effect, an anti-reflection film 4 including a translucent film may be provided between the light shielding film and the phase shift film. The light reflected on the light-shielding film and the light reflected on the anti-reflection film (the light reflected on the light-shielding film (the second reflected light of the stray light) and the stray light on the surface of the anti-reflection film can be provided by the anti-reflection film 4 The reflected light is set to a mutually weaker manner to set the optical path length, whereby the phase difference can be prevented from reaching 2π and mutually reinforcing.

The antireflection film of the present invention is not particularly limited as long as it has an antireflection function and can be formed between the light shielding film and the phase shift film in the light shielding region, but a metal film or a metal compound film can be preferably used. Wait.

Examples of the material of the antireflection film include chromium oxide (CrO), chromium oxynitride (CrON), chromium nitride (CrN), titanium oxide (TiO), tantalum oxide (TaO), and nickel aluminum oxide (NiAlO). Among them, chromium oxide (CrO), nitrogen oxide can be preferably used. Chromium (CrON).

The thickness of the anti-reflection film is designed to be the optical path length such that the light reflected on the light-shielding film and the light reflected on the anti-reflection film are mutually weakened.

The thickness of the antireflection film is preferably such that the phase reflected by the light reflected on the light shielding film and the light reflected on the antireflection film are in a range of π ± 10 by the light reflected from the light shielding film. The thickness of the film is preferably a thickness in the range of π ± 5, and particularly preferably a thickness of π.

The reason for this is that the light reflected on the light-shielding film and the light reflected on the anti-reflection film can be preferably weakened, so that the problem caused by stray light can be preferably prevented.

The specific thickness of the antireflection film is appropriately selected depending on the material of the antireflection film, etc., and is not particularly limited, and may be in the range of 0.01 μm to 0.1 μm, and preferably in the range of 0.02 μm to 0.05 μm. The reason for this is that when the above range is not satisfied, there is a possibility that it is difficult to form an antireflection film with a uniform thickness, and when it exceeds the above range, there is a possibility that the film formation time and cost of the antireflection film increase. .

In addition, as the antireflection film, in addition to the phase of the light to be transmitted, for example, a surface of a metal film or the like may be roughened to impart a function of diffusing light.

As the antireflection method of the surface of the phase shift film 5, a translucent low reflection film may be provided on the surface of the phase shift film 5. In particular, when the phase shift film 5 is chromium oxynitride, there is a case where the surface has a metallic luster, and in this case, a low reflection layer containing chromium oxide is effective.

(Production method)

2(a) to (f) are views showing the manufacturing steps of the large phase shift mask 1 of the present invention shown in Fig. 1(a).

In order to produce the large-sized phase shift mask 1 of the present embodiment, first, a mask blank 20 in which a light-shielding film 3 is laminated on a transparent substrate 2 and an anti-reflection film 4 is laminated as necessary is provided (FIG. 2(a)). The transparent substrate 2 is generally made of optically ground synthetic quartz having a thickness of 8 mm to 12 mm. When the light shielding film 3 of the mask blank 20 is a chromium film or a chromium nitride film, film formation is performed by a sputtering method. Further, when the antireflection film is chromium oxide, the film formation is carried out by sputtering. A blank in which the light-shielding film is chromium and the anti-reflection film is chromium oxide is the most common, and a commercially available product can be easily obtained.

Next, the light-shielding film 3 of the mask blank 20 and the anti-reflection film 4 are patterned by a usual method (first pattern forming step). That is, a photosensitive photoresist corresponding to the exposure wavelength of the laser beam drawing device is applied to the light-shielding film 3 or the anti-reflection film 4, and is baked at a predetermined time after coating to form a light-shielding film having a uniform thickness. Photoresist film. Next, a pattern of the light-shielding region 7 is drawn on the light-shielding film for a light-shielding film by a laser beam drawing device, and development is performed to form a light-shielding film photoresist 16 (Fig. 2(b)). Generally, the light-shielding region 7 removes the region of the transmissive region 6 and the phase-shift region 8 from the entire effective area of the mask. Further, if necessary, a mark for alignment is formed by the light shielding film for alignment with the position of the phase shift region pattern.

Next, the light-shielding film exposed from the photoresist 16 for the light-shielding film is etched away, The remaining photoresist is peeled off to obtain a substrate 21 having a light-shielding film patterned in a shape of the light-shielding region 7 (Fig. 2(c)). Although the etching of the light-shielding film 3 can be applied by a wet etching method or a dry etching method, as described above, with the enlargement of the photomask for a flat panel display, dry etching consumes a large cost in the enlargement of the etching apparatus, and is also difficult. The uniformity of etching over a large area is controlled, and therefore, in terms of cost, wet etching is preferred. When the light-shielding film 3 is a chromium-based film, a wet etchant to which perchloric acid is added to cerium (IV) ammonium nitrate can be used to form a pattern favorably. In addition, when the material of the anti-reflection film 4 is a chromium-based material such as chrome oxide, the wet etching agent can be used to simultaneously etch the chromium-based light-shielding film to form a pattern.

In the present embodiment, after the step of patterning the light-shielding film 3, the inspection of the substrate 21 with the patterned light-shielding film is performed, and the step of correcting the defect can be performed as needed.

Next, a phase shift film 5 is formed on the entire surface of the substrate 21 to which the patterned light-shielding film is attached (Fig. 2(d)). Here, the phase shift film 5 preferably contains a material which is the same as the above-described light shielding film 3. When the light-shielding film 3 is a chromium-based material as described above, the phase shift film 5 contains one or more of elements such as oxygen, nitrogen, and carbon in the chromium, and has a relatively high refractive index to a predetermined range. The ratio of the component of the material is selected by the way of the light transmittance. Specifically, the constituent ratio of each element is selected from chromium oxide, chromium oxynitride, and chromium oxycarbonitride.

The film formation system of the phase shift film 5 is the same as the method of forming the chromium light-shielding film, and a vacuum film formation method such as a sputtering method can be used.

Next, by the second pattern forming step, the light-shielding region 7 as the lower light-shielding film pattern is aligned, and the phase shift film 5 is patterned. That is, a photosensitive photoresist corresponding to the exposure wavelength of the laser beam drawing device is applied onto the phase shift film 5, and after coating, it is baked for a predetermined period of time to form a resist film for a phase shift film having a uniform thickness. Next, a pattern of a region in which the phase shift region 8 and the light-shielding region 7 coincide with each other is formed on the phase shift film resist film by the laser beam drawing device. Then, the exposed phase shift film was developed with a photoresist to obtain a patterned phase shift film resist 17 (Fig. 2(e)).

Next, the phase shift film 5 exposed from the phase shift film resist 17 is etched and removed, and a phase shift film which is patterned into a shape in which the phase shift region 8 and the light shielding film pattern 7 match each other is obtained. Here, if the phase shift film is formed of a material containing at least one of oxygen, nitrogen, and carbon in the chromium, the pattern processing can be performed by the same wet etching as the etching of the light shielding film 3 formed of the chromium or chromium compound. As described above, the cost advantage of the pattern processing step is large.

Then, the photoresist film for the remaining phase shift film is peeled off to complete the large phase shift mask (Fig. 2(f)).

Hereinabove, a method of manufacturing a phase shift mask according to an embodiment of the present invention has been described with reference to Fig. 2 . In the manufacturing method, in particular, if the material of the light shielding film 3 is chromium and the material of the phase shift film 5 is a chromium compound containing at least one of oxygen, nitrogen, and carbon, a commercially available chrome hard mask can be used. As the starting material of the manufacturing step, and the etching step is wet etching, the cost advantage in manufacturing is obvious.

(other)

The phase shift mask of the present invention can be used to pattern a photoresist used for pattern formation of the above TFT array substrate or the like.

The photoresist which can be used together with the phase shift mask of the present invention can be appropriately selected depending on the electrode material of the TFT substrate, the developer, the projection type exposure machine, and the like, and is not particularly limited.

For example, when an exposure machine manufactured by Nikon Corporation is used as an exposure machine, AZ1500 is used as a photoresist, and when AZ300MIF is used as a developing solution, an exposure beam which can reduce a transmittance of a phase shift mask of 5% or less can be used. The influence, that is, the light having an exposure intensity of 5% or less makes the photoresist difficult to be drawn. Therefore, it is difficult to react with the side peak in the exposure intensity distribution, and the patterning of the photoresist can be favorably performed.

Further, the thickness of the photoresist is not particularly limited as long as it can be patterned into a desired shape by using the phase shift mask of the present invention, but it may be in the range of 1.0 μm to 10.0 μm, and preferably. It is in the range of 1.2 μm to 5.0 μm, and particularly preferably in the range of 1.5 μm to 4.0 μm. The phase shift mask of the present invention can be used to form a photoresist pattern having a desired shape by making the thickness of the photoresist within the above range.

Further, the photoresist which can be used together with the phase shift mask of the present invention is not limited to the above.

Furthermore, the present invention is not limited to the above embodiment. The above embodiments are illustrative and have the technical idea disclosed in the scope of the patent application of the present invention. Those having substantially the same constitution and obtaining the same effects are included in the technical scope of the present invention.

[Examples]

(About the contrast of the exposure intensity distribution)

Fig. 3 is an explanatory view showing an effect of improving the contrast of the exposure intensity distribution of the large phase shift mask (Example 1) of the present invention with a conventional binary mask (Comparative Example 1). Fig. 3 (a) is a plan view showing a line and gap pattern of the large phase shift mask (Example 1) of the present invention, and Fig. 3 (b) shows a binary mask (Comparative Example 1) as a conventional technique. A plan view of the line and gap patterns, and Fig. 3(c) is a view obtained by comparing the exposure intensity distributions on the image planes of the masks shown in Figs. 3(a) and 3(b).

Further, Table 1 is a table obtained by comparing the effect of improving the contrast of the exposure intensity distribution of the large phase shift mask (Example 1) of the present invention with a conventional binary mask (Comparative Example 1).

The pattern of the large phase shift mask of the present invention as the first embodiment of Fig. 3(a) is a line and gap pattern of 4 μm pitch, and the width a of the transmissive region 6 is 3 μm. The phase shift region 8 disposed adjacent to both sides of the transmissive region 6 has a width b of 0.4 μm, a transmittance of 5.2%, and a phase inverted by π (180 degrees). Further, the light-shielding region 7 has a width of 0.2 μm and a transmittance of 0%. Further, the transmittance of each region was calculated by the transmittance of the transmission region 6 being 100%.

The pattern of the binary mask as Comparative Example 1 of FIG. 3(b) is a line and gap pattern of 4 μm pitch, and the width d of the transmission region is 3 μm, and the light shielding region is The width e is 1 μm.

Fig. 3(c) is a graph showing the results of the exposure of the exposure apparatus by simulation, and the light source of the exposure apparatus is calculated by a three-wavelength hybrid light source of g line, h line, and i line. The vertical axis of the graph normalizes the maximum value of the intensity of the exposure beam in the transmission region on the imaging surface as 1, and the horizontal axis of the graph indicates the position on the imaging surface. The exposure beam intensity distribution of the large phase shift mask corresponding to the position of the AA cross section of Fig. 3(a) is shown in the exposure beam intensity distribution curve 31. Further, the exposure beam intensity distribution of the binary mask corresponding to the position of the BB section of FIG. 3(b) is shown on the exposure beam intensity distribution curve 32.

The maximum intensity of the light intensity distribution of the large phase shift mask exposed beam intensity distribution curve 31 shown in Fig. 3(c) is 0.747, the minimum value is 0.324, and the difference between the maximum value and the minimum value is 0.423. On the other hand, the maximum intensity of the light intensity distribution of the exposure beam intensity distribution curve 32 as a binary mask of the prior art is 0.782, the minimum value is 0.399, and the difference between the maximum value and the minimum value, that is, the contrast ratio is 0.383. That is, the contrast of the exposure beam on the imaging surface of the conventional binary mask is 0.383, and the contrast of the exposure beam of the large phase shift mask of the present invention is 0.423, and the contrast is improved by 0.04, which is visible in the ratio of contrast. Approximately 10% improvement. This result is collectively described in the effect of the large phase shift mask of Table 1.

According to the above exposure simulation results, it is understood that the present invention can appropriately arrange the phase shift regions in the large mask, improve the contrast of the exposure intensity distribution on the image plane, and stably form a finer pattern.

(Relationship between the analytical limit of the exposure machine and the drawing pattern of the phase shift mask)

<Production of phase shift mask>

A commercially available mask blank with a thickness of 10 mm of synthetic quartz (transparent substrate), a 100 nm thick chromium film (light-shielding film), and a 25 nm thick chromium oxide film (anti-reflection film) is prepared. And coating a suitable photosensitive photoresist on the anti-reflection film, baking after coating for a predetermined time to form a photoresist film for a light-shielding film having a uniform thickness. Next, a pattern of a light-shielding region is drawn on the light-shielding film for a light-shielding film by a laser beam drawing device, and development is performed to form a photoresist for a light-shielding film.

Next, using a wet etchant to which perchloric acid is added to cerium (IV) ammonium nitrate, the antireflection film and the light shielding film exposed from the photoresist for the light shielding film are etched away, and the remaining photoresist is removed and removed. A substrate having a light-shielding film and an anti-reflection film patterned in a shape of a light-shielding region is obtained.

Next, a chromium oxynitride film (phase shift film) is formed on the entire surface of the light-shielding film and the anti-reflection film substrate on which the pattern is formed by a sputtering method.

Then, by the second pattern forming step, the light-shielding region as the light-shielding film pattern of the lower layer is aligned, and the photoresist film for the phase-shift film is formed by the same method as the photoresist for the light-shielding film. . Next, a pattern of a region in which the phase shift region coincides with the light-shielding region is drawn on the resist film for phase shift film by a laser beam drawing device, and then developed to obtain a patterned phase resist film resist.

Then, similarly to the above-described light-shielding film and anti-reflection film, the phase shift film exposed from the phase shift film photoresist is etched away, and a phase shift film having a shape in which the phase shift region and the light-shielding film pattern are matched is obtained. Then, the photoresist film for the remaining phase shift film is peeled off. By the above steps, a transmission region (line width 1.9 μm), a phase shift region (line width 2.0 μm), and a light-shielding region are arranged, and an anti-reflection film and a phase shift are sequentially laminated on the light-shielding film in the light-shielding region. Large phase shift mask for the membrane.

<Production of photoresist pattern>

Using the above-described phase shift mask and using an exposure machine manufactured by Nikon with a resolution limit of 3 μm, a photoresist (AZ1500) having a thickness of 1.6 μm formed on a glass substrate was subjected to pattern exposure, and after development processing, A 1.9 μm photoresist pattern was formed.

(about the width of the phase shift region in the phase shift mask)

Figure 6 is a plan view showing the pattern of the large phase shift mask of the present invention, 7 is a view showing an exposure intensity distribution on an image plane of the large phase shift mask shown in FIG. 6, FIG. 8 is an enlarged view of a portion C of FIG. 7, and FIG. 9 is an enlarged view of a portion D of FIG.

As a large phase shift mask, the width of the transmissive region is set to 5 μm, and the width b of the phase shift region is set to 0.25 μm (Example 3), 0.5 μm (Example 4), 0.75 μm (Example 5), and 1.0. Μm (Example 6), 1.5 μm (Example 7), 2.0 μm (Example 8), 2.5 μm (Example 9), 3.0 μm (Example 10), 3.5 μm (Example 11), and 4.0 μm In the (Example 12), the exposure intensity distribution (light intensity) of the exposure machine manufactured by Nikon Corporation was simulated. Further, the simulation conditions other than the pattern of the large phase shift mask described above are the same as in the first embodiment. The results are shown in Figures 7-9.

The smaller the exposure intensity shown in FIG. 8, the sharper the waveform shown in FIG. 7, but the phase shift effect on the edge position of the pattern of the large phase shift mask is greater than the width of the phase shift region. At 2.0 μm, the effect of the phase shift effect is not exhibited (the phase shift effect reaches the limit).

Further, as shown in FIG. 9, as the width of the phase shift region becomes larger, the value of the side peak also becomes larger.

In the present invention, the width of the phase shift region can be set in such a manner that the side peak does not affect the photoresist according to the sensitivity of the photoresist.

The width of the phase shift is preferably 0.25 μm to 3.5 μm, which is a width of a side peak of 5% or less, depending on the actual performance of the photoresist used in forming the TFT array substrate.

1‧‧‧ Large phase shift mask

2‧‧‧Transparent substrate

3‧‧‧Shade film

4‧‧‧Anti-reflective film

5‧‧‧ phase shift film

6‧‧‧Transmission area

7‧‧‧ shading area

8‧‧‧ Phase shift area

10‧‧‧Light amplitude distribution in the transmissive region

11‧‧‧Light amplitude distribution in the phase shift region

12‧‧‧Amplitude distribution of light containing phase shift effects

13‧‧‧Light intensity distribution in the transmissive area

14‧‧‧Intensity distribution of light containing phase shift effects

15‧‧‧ Effect of phase shifting area

16‧‧‧Photoresist formed as a pattern of light-shielding film

17‧‧‧Photoresist formed as a phase shifting region and a pattern of light-shielding films

20‧‧‧Photomask blanks

21‧‧‧ Patterns of mask blanks with a light-shielding film

30‧‧‧ Binary mask

31‧‧‧Light intensity distribution of large phase shift masks

32‧‧‧Light intensity distribution of binary masks

40‧‧‧Exposure beam

50‧‧‧Photomask

51‧‧‧Transparent substrate

52‧‧‧Shade film

53‧‧‧ Semi-transparent film

54‧‧‧Lighting Department

55‧‧‧ semi-transmission department

56‧‧‧Micro pattern department

57‧‧‧Transmission Department

60‧‧‧Transfer body

61‧‧‧Substrate

62a, 62b‧‧‧ film laminated on the substrate 61

63‧‧‧Photoresist film

63a‧‧‧Residual film area of thick film

63b‧‧‧Residual film area of film

63c‧‧‧Micro pattern area

63d‧‧‧A region that does not have a residual film

73a, 73b, 73c, 73d‧‧‧ The distribution shape of the amount of exposure light when exposed by a halftone mask

74a, 74b, 74c, 74d‧‧‧ The distribution shape of the amount of exposure light when the fine pattern is exposed by the binary mask

75‧‧‧Exposure by positive photoresist removal

a, b, c, d, e‧‧ ‧ width

D‧‧‧thickness

BRIEF DESCRIPTION OF THE DRAWINGS Figures 1 (a) to (c) are cross-sectional views showing the construction and action of a large phase shift mask of the present invention.

2(a) to (f) are cross-sectional views showing the manufacturing steps of the large phase shift mask of the present invention.

3(a) to 3(c) are explanatory diagrams for comparing the effect of contrast enhancement of the exposure intensity distribution of the large phase shift mask of the present invention with a conventional binary mask.

4(a) and 4(b) are cross-sectional views schematically showing the transfer of a fine pattern of a halftone mask as a conventional technique.

Fig. 5(a) is a view schematically showing an exposure intensity distribution when exposure is performed by the halftone mask of Fig. 4, and Fig. 5(b) is a schematic view for exposing a fine pattern by using a binary mask for comparison. A map of the exposure intensity distribution.

Fig. 6 is a schematic plan view showing an example of a large phase shift mask of an embodiment of the present invention.

Figure 7 is a graph illustrating the exposure intensity distribution of a large phase shift mask of an embodiment of the present invention.

Figure 8 is an enlarged view of a portion C of Figure 7.

Figure 9 is an enlarged view of a portion D of Figure 7.

1‧‧‧ Large phase shift mask

2‧‧‧Transparent substrate

3‧‧‧Shade film

4‧‧‧Anti-reflective film

5‧‧‧ phase shift film

6‧‧‧Transmission area

7‧‧‧ shading area

8‧‧‧ Phase shift area

10‧‧‧Light amplitude distribution in the transmissive region

11‧‧‧Light amplitude distribution in the phase shift region

12‧‧‧Amplitude distribution of light containing phase shift effects

13‧‧‧Light intensity distribution in the transmissive area

14‧‧‧Intensity distribution of light containing phase shift effects

15‧‧‧ Effect of phase shifting area

16‧‧‧Photoresist formed as a pattern of light-shielding film

40‧‧‧Exposure beam

Claims (5)

A large phase shift mask comprising a transparent substrate, a light shielding film formed on the transparent substrate, and a translucent phase shift film formed on the transparent substrate, wherein the phase shift mask has: an exposed a transmissive region of the transparent substrate, a light-shielding region in which the light-shielding film is provided on the transparent substrate, and a phase shift region in which the phase shift film is provided on the transparent substrate; and the transmissive region and the phase shift region a pattern adjacent to each other, wherein a phase shift region is disposed adjacent to the transmissive region and the light-shielding region, and an exposure beam transmitted through the phase shift region is inverted in phase with respect to an exposure beam transmitted through the transmissive region; a chromium or chromium compound as a main component, wherein the phase shift film is mainly composed of chromium oxide or chromium oxynitride, and a phase shift film is laminated on the light shielding film of the light shielding region; and the light shielding film and the phase in the light shielding region Between the displacement films, an anti-reflection film is also included. A large phase shift mask according to the first aspect of the invention, wherein the width of the phase shift region is a width in a range of 0.25 μm or more and 3.5 μm or less. A large phase shift mask according to the first aspect of the invention, wherein the width of the narrowest portion of the transmissive region is a width in a range of 1 μm or more and 6 μm or less. The large phase shift mask of claim 1, wherein the phase shift film of the exposure beam has a light transmittance of 4% or more and 15% or less. A method for manufacturing a large-scale phase shift mask, comprising: a transparent substrate, a light shielding film formed on the transparent substrate, and a half formed on the transparent substrate, wherein the phase shift mask is provided a transparent phase shift film; and a light-shielding region in which the transparent substrate is exposed, a light-shielding region in which the light-shielding film is provided on the transparent substrate, and a phase-shift region in which the phase shift film is provided on the transparent substrate; a pattern in which the transmissive region is adjacent to the phase shift region, and a phase shift region is disposed adjacent to the transmissive region and the light-shielding region, and an exposure beam transmitted through the phase shift region is exposed to the transmissive region The phase of the beam is reversed, and the phase shift film is laminated on the light shielding film in the light shielding region, and the antireflection film is further included between the light shielding film and the phase shift film in the light shielding region; and the method includes the following steps: a light-shielding film containing chromium as a main component and oxygen in the form of chromium on one surface of the transparent substrate a step of applying a photosensitive photoresist to a blank of an anti-reflection film containing a nitrogen oxide as a main component or a chromium-based oxide to prepare a blank with a photosensitive photoresist; and a blank with a photosensitive photoresist a step of exposing and developing a desired pattern by a drawing device, performing wet etching, removing the photosensitive photoresist, and patterning the light-shielding film and the anti-reflection film; and forming the transparent substrate and the patterned film The above light shielding film and the above anti-reverse a step of forming a phase shift film comprising a chromium compound on the film; and applying a photosensitive photoresist to the formed phase shift film, exposing and developing the desired pattern by using a drawing device, and performing wet etching to sensitize The photoresist is removed to form the phase shifting film described above.