JP2009237419A - Multi-gradation photomask, manufacturing method thereof, and pattern transfer method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multi-gradation photomask which can be used as a photomask having more than three gradations. <P>SOLUTION: The multi-gradation photomask has a mask pattern including a light shielding part, a light-transmissive part, and a light transflective part for reducing an exposure light transmittance by a prescribed amount, on a transparent substrate. The light shielding part is constituted of a light shielding film formed on at least the transparent substrate, and the light-transmissive part is formed of an exposed portion of the transparent substrate, and the light transflective part includes a first light transflective part composed of a light transflective film formed on the transparent substrate, a second light transflective part composed of a fine pattern formed by the light transflective film and having a resolution limit under an exposure condition or lower resolution, and a third light transflective part having a resolution limit under an exposure condition or lower resolution. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

 The present invention relates to a multi-tone photomask suitably used for manufacturing a liquid crystal display (Liquid Crystal Display: hereinafter referred to as LCD), a manufacturing method thereof, and a pattern transfer method using the photomask.

  At present, in the field of LCD, a thin film transistor liquid crystal display (hereinafter referred to as TFT-LCD) is easily reduced in thickness and consumes less power than a CRT (cathode ray tube). Commercialization is progressing rapidly. A TFT-LCD includes a TFT substrate having a structure in which TFTs are arranged in pixels arranged in a matrix, and a color filter in which red, green, and blue pixel patterns are arranged corresponding to each pixel. It has a schematic structure superimposed under the intervention of. In TFT-LCD, the number of manufacturing processes is large, and the TFT substrate alone is manufactured using 5 to 6 photomasks. Under such circumstances, a method of manufacturing a TFT substrate using four photomasks has been proposed.

  In this method, the number of masks to be used is reduced by using a photomask called a gray tone mask having a semi-transparent portion (gray tone portion) in addition to the light shielding portion and the translucent portion. Here, the semi-transparent portion means that when a pattern is transferred to a transfer object using a mask, the amount of exposure light transmitted therethrough is reduced by a predetermined amount, and the photoresist film on the transfer object after development is developed. The part that controls the amount of remaining film.

As a gray tone mask used here, Patent Document 1 discloses a structure in which a semi-transparent portion is formed with a fine pattern below the resolution limit of an LCD exposure machine using a gray tone mask. Yes. In addition, a structure in which the semi-transparent portion is formed of a semi-transparent semi-transparent film is also conventionally known. Regardless of the structure, it is possible to expose the semi-translucent portion with a predetermined amount of light exposure, and transfer two transfer patterns having different resist residual film values onto the transfer target. Therefore, the number of masks required for manufacturing electronic devices such as TFT-LCDs can be reduced by carrying out the process of two conventional photomasks using one graytone mask. The

  In addition to the light-shielding portion and the light-transmitting portion, a 4-tone photomask having a first semi-transparent portion and a second semi-transparent portion having different light transmittances can be manufactured by a lithography process with a small number of times of drawing. A photomask manufacturing method is disclosed in Patent Document 2 below.

JP 2002-196474 A JP 2007-249198 A

  The gray-tone mask disclosed in Patent Document 1 is a three-tone photomask having a light-shielding portion, a light-transmitting portion, and a semi-light-transmitting portion, and changing the exposure light transmittance in three stages. However, since the semi-transparent portion is formed by the pattern of the light shielding film, there is a limitation on the exposure light transmittance of the gray tone portion. For example, there is a limit to the line width that can be drawn and patterned uniformly. As the line width decreases, the uniformity deteriorates and eventually reaches the drawing limit. Therefore, even if an attempt is made to form a gray tone portion having a relatively high transmittance, the desired drawing and patterning cannot be performed, and as a result, there is a disadvantage that only a predetermined transmittance or less can be designed according to the exposure conditions.

In addition, according to the method for manufacturing a four-tone photomask disclosed in Patent Document 2, a semi-transparent film having a desired transmittance is used in the gray tone portion, so that the material and film thickness can be selected. It is possible to design a gray tone portion having a desired plurality of transmittances relatively freely. However, since it is necessary to form a new film as the number of gradations increases, there is an inconvenience that the number of film forming steps is increased and the probability of occurrence of defects is increased accordingly. Furthermore, even when a semi-transparent film is used, the material having a high transmittance has restrictions on the material, and when the film thickness becomes extremely small, the in-plane distribution of the film thickness deteriorates.
Therefore, in the production of a multi-tone mask with more than 3 gradations, it is possible to create semi-transparent portions having different transmittances without increasing the film forming process, and further, semi-transparent light having a relatively high transmittance. There is a problem in manufacturing a multi-tone mask having a portion.

  The present invention has been made in view of the above-described conventional circumstances, and has a light-shielding portion, a light-transmitting portion, and a semi-light-transmitting portion, and can be used as a desired photomask exceeding three gradations. A first object is to provide a multi-tone photomask having transmittance. It is a second object of the present invention to provide a method for manufacturing a multi-tone photomask capable of manufacturing such a multi-tone photomask by a simple process that is efficient and has a low probability of occurrence of defects. And Furthermore, a third object of the present invention is to provide a pattern transfer method using the multi-tone photomask.

In order to solve the above problems, the present invention has the following configuration.
(Structure 1) A mask pattern including a light-shielding portion, a light-transmitting portion, and a semi-light-transmitting portion that reduces the exposure light transmittance by a predetermined amount is provided on the transparent substrate, and the light-shielding portion is formed on at least the transparent substrate. The light-transmitting part is formed by the exposed transparent substrate, and the semi-transparent part is a first semi-transparent part formed by a semi-transparent film formed on the transparent substrate. And a second semi-transparent portion in which a fine pattern having a line width less than a resolution limit under an exposure condition is formed on the semi-transparent film on the transparent substrate. Multi-tone photomask.
The photomask of the present invention has a first semi-transparent portion made of a semi-transparent film. In addition, a second semi-transparent portion having a fine pattern having a line width less than the resolution limit under the exposure condition formed on the semi-transparent film is also provided. That is, the first semi-transparent portion is made of a semi-transparent film having no fine pattern, whereas the second semi-transparent film has a fine pattern. Here, “a fine pattern having a line width less than or equal to the resolution limit under exposure conditions” is either the line width of the semi-transparent film portion or the line width of the space portion formed in the semi-transparent film pattern. Means that the dimensions are below the resolution limit under the exposure conditions. That is, the pattern formed by the semi-transparent film has a fine line width or space width to such an extent that the pattern shape is not resolved.

(Configuration 2) A mask pattern including a light shielding part, a light transmitting part, and a semi-light transmitting part for reducing the exposure light transmittance by a predetermined amount is provided on the transparent substrate, and the light shielding part is formed on at least the transparent substrate. The light-transmitting part is formed by the exposed transparent substrate, and the semi-transparent part is a first semi-transparent part formed by a semi-transparent film formed on the transparent substrate. And a third semi-transparent portion in which a fine pattern having a line width less than a resolution limit under exposure conditions is formed on at least the light shielding film on the transparent substrate. Multi-tone photomask.
Here, “a fine pattern having a line width less than or equal to the resolution limit under exposure conditions” means that either the line width of the light shielding film portion or the line width of the space portion formed in the light shielding film film pattern is exposed. It is the same as the above in that the dimensions are below the resolution limit under the conditions.

(Configuration 3) A transparent substrate has a mask pattern including a light shielding portion, a light transmitting portion, and a semi-light transmitting portion for reducing the exposure light transmittance by a predetermined amount, and the light shielding portion is formed on at least the transparent substrate. The light-transmitting part is formed by the exposed transparent substrate, and the semi-transparent part is a first semi-transparent part formed by a semi-transparent film formed on the transparent substrate. And on the transparent substrate, a second semi-transparent portion in which a fine pattern having a line width less than a resolution limit under an exposure condition is formed on the semi-transparent film, and at least the transparent substrate A multi-tone photomask comprising: a third semi-transparent portion in which a light-shielding film is formed with a fine pattern having a line width less than a resolution limit under exposure conditions.

(Structure 4) The multi-layered structure according to any one of Structures 1 to 3, wherein the light shielding film is made of a material containing chromium as a main component, and the semi-transparent film is made of a material containing metal silicide as a main component. Tone photomask.
(Configuration 5) The configuration 1 is characterized in that the light-shielding portion includes at least the semi-transparent film and the light-shield film, and an etching stopper film is provided between the semi-transparent film and the light-shield film. 4. A multi-tone photomask according to any one of items 1 to 3.

(Structure 6) A method for producing a multi-tone photomask having a mask pattern comprising a light-shielding portion, a light-transmitting portion, and a semi-light-transmitting portion that reduces exposure light transmittance by a predetermined amount on a transparent substrate, the transparent substrate A step of preparing a photomask blank having a semi-transparent film and a light-shielding film in this order; and a resist film formed on the light-shielding film of the photomask blank is drawn and developed to form a predetermined first resist A step of forming a pattern, a step of etching the light shielding film using the first resist pattern as a mask to form a light shielding film pattern, and an etching of the semi-transparent film using the first resist pattern or the light shielding film pattern as a mask And drawing and developing a resist film formed on the entire surface of the substrate including the patterned light-shielding film and the semi-transparent film, thereby forming a second resist pattern. And a step of etching the light shielding film exposed using the second resist pattern as a mask, wherein at least one of the first resist pattern and the second resist pattern includes a fine pattern, and is formed on the transparent substrate A light-shielding portion made of a semi-light-transmitting film and a light-shielding film, a light-transmitting portion in which the transparent substrate is exposed, a semi-light-transmitting portion made of a semi-light-transmitting film formed on the transparent substrate, and the transparent A fine pattern of a semi-transparent film having a line width less than or equal to the resolution limit under exposure conditions and / or a fine pattern of a light shielding film having a line width less than or equal to the resolution limit under exposure conditions is formed on the substrate. A method for manufacturing a multi-tone photomask, comprising forming a semi-translucent portion.

(Structure 7) In the case where a semi-transparent portion made of a fine pattern of a light-shielding film below the resolution limit under exposure conditions is formed on the transparent substrate, the second resist covering a region where the fine pattern of the light-shielding film is formed 7. The method for manufacturing a multi-tone photomask according to Structure 6, wherein the pattern is formed wider than the region width.
(Configuration 8) A method for manufacturing a multi-tone photomask having a mask pattern comprising a light shielding portion, a light transmitting portion, and a semi-light transmitting portion for reducing exposure light transmittance by a predetermined amount on a transparent substrate, A step of preparing a photomask blank having a semi-transparent film and a light-shielding film in this order; and a resist film formed on the light-shielding film of the photomask blank is drawn and developed to form a predetermined first resist Forming a pattern, forming a light shielding film pattern by etching the light shielding film using the first resist pattern as a mask, and forming the patterned light shielding film and the translucent film on the entire surface of the substrate A process of drawing and developing a resist film to form a predetermined second resist pattern, and the semi-transparent film or the light-shielding film exposed using the second resist pattern as a mask. Etching a lower semi-transparent film, and including a fine pattern in at least one of the first resist pattern and the second resist pattern and formed on the transparent substrate and a light-shielding film A light-transmitting portion formed by exposing the transparent substrate, a semi-light-transmitting portion formed by a semi-transmissive film formed on the transparent substrate, and resolution on the transparent substrate under exposure conditions. Forming a semi-transparent portion having a fine pattern of a semi-transparent film having a line width less than a limit and / or a fine pattern of a light-shielding film having a line width less than a resolution limit under exposure conditions. A method for producing a multi-tone photomask, which is characterized.

(Structure 9) The method for manufacturing a multi-tone photomask according to any one of Structures 6 to 8, wherein the light shielding film and the semi-transparent film are made of a material having etching selectivity.
(Structure 10) The multi-tone photomask according to Structure 9, wherein the light shielding film is made of a material containing chromium as a main component, and the semi-transparent film is made of a material containing metal silicide as a main component. Production method.
(Structure 11) The method for producing a multi-tone photomask according to any one of Structures 6 to 8, wherein an etching stopper film is provided between the light shielding film and the semi-transparent film.

(Configuration 12) A method for producing a multi-tone photomask having a mask pattern comprising a light-shielding portion, a light-transmitting portion, and a semi-light-transmitting portion that reduces exposure light transmittance by a predetermined amount on a transparent substrate, the transparent substrate A step of preparing a photomask blank having a light shielding film thereon, a step of drawing and developing a resist film formed on the light shielding film of the photomask blank to form a first resist pattern, and the first resist pattern Etching the light shielding film using the mask as a mask to form a light shielding film pattern; and removing the first resist pattern and then forming a semi-transparent film on the entire surface of the substrate including the patterned light shielding film; Drawing and developing a resist film formed on the semi-translucent film to form a predetermined second resist pattern, and using the second resist pattern as a mask Etching the semi-transparent film or the semi-transparent film and the light-shielding film in order, and at least one of the first resist pattern and the second resist pattern includes a fine pattern, on the transparent substrate A light-shielding portion made of a light-shielding film and a semi-light-transmissive film, a light-transmissive portion formed by exposing the transparent substrate, a semi-light-transmissive portion made of a semi-light-transmissive film formed on the transparent substrate, According to the fine pattern of the semi-transparent film having a line width less than the resolution limit under the exposure conditions and / or the fine pattern of the light shielding film having the line width less than the resolution limit under the exposure conditions formed on the transparent substrate A method for manufacturing a multi-tone photomask, comprising: forming a semi-transparent portion.

(Structure 13) Using the multi-tone photomask according to any one of Structures 1 to 5 or the multi-tone photomask according to the manufacturing method according to any of Structures 6 to 12, exposure light is applied to the transfer object. A pattern transfer method comprising: forming a multi-tone transfer pattern on a transfer object.

According to the present invention, a multi-tone photomask that can be used as a photomask having more than three tones can be obtained.
In addition, according to the method of manufacturing a multi-tone photomask of the present invention, such a multi-tone photomask can be efficiently used by a photolithography method using a combination of a light-shielding film and a semi-transparent film. It can be manufactured by a simple process with a low probability of occurrence of defects. The multi-tone photomask of the present invention includes a semi-transparent portion having a high transmittance, and a semi-transparent portion having a desired transmittance can be easily manufactured.

Further, according to the pattern transfer method using the multi-tone photomask according to the present invention, high-precision multi-tone pattern transfer can be carried out. Can be significantly reduced. Further, as will be described later, the exposure amount to the transfer target can be made constant (matched) regardless of the line width of the pattern for a predetermined semi-transparent portion on the photomask.

The best mode for carrying out the present invention will be described below with reference to the drawings.
[First Embodiment]
FIG. 1 is a cross-sectional view for explaining a first embodiment of a multi-tone photomask according to the present invention and a pattern transfer method using the multi-tone photomask.
The multi-tone photomask 10 shown in FIG. 1 is used as a multi-tone gray tone mask for manufacturing a thin film transistor (TFT), a color filter, a plasma display panel (PDP), etc. of a liquid crystal display device (LCD), for example. A resist pattern 23 having different thicknesses stepwise or continuously is formed on the transfer target 20 shown in FIG. In FIG. 1, reference numeral 22 denotes a multi-layered film laminated on the substrate 21 in the transfer target 20.

Specifically, the photomask 10 of the present embodiment includes a light shielding portion 11 that shields exposure light (transmittance is approximately 0%) when the photomask 10 is used, and a surface of a transparent substrate 14 such as a glass substrate. Is exposed and transmits the exposure light, and the exposure light transmittance of the light transmitting portion 12 is 100%, the transmittance is about 10 to 80%, preferably about 20 to 70%. In this range, the first semi-transparent part 13A, the second semi-transparent part 13B, and the third semi-transparent part 13C having different exposure light transmittances in three stages are configured. In the present embodiment, the light-shielding portion 11 is formed by sequentially providing a light-shielding film 15 made of a laminate of a light-semitransmissive semi-transparent film 16, a light-shielding layer 15a, and an antireflection layer 15b on a transparent substrate 14. Has been. Further, as described above, the light transmitting portion 12 is a region where the surface of the transparent substrate 14 is exposed. In addition, the first semi-transparent portion 13 </ b> A among the semi-transparent portions is formed by a light semi-transmissive semi-transparent film 16 formed on the transparent substrate 14. The material and film thickness of the semi-transmissive film 16 are set so that the exposure light transmittance of the first semi-transmissive part 13A has a desired value. Further, the second semi-transparent portion 13B is constituted by a fine pattern 17 having a resolution limit or less under the exposure conditions formed by the semi-transparent film 16. The line width of the fine pattern 17 formed by the semi-transparent film 16 is set so that the exposure light transmittance of the second semi-transparent portion 13B becomes a desired value. Further, the third semi-transparent portion 13 </ b> C is configured by a fine pattern 18 having a resolution limit or less under the exposure conditions formed by the laminated film of the semi-transparent film 16 and the light shielding film 15. The line width of the fine pattern 18 formed by the laminated film of the semi-transparent film 16 and the light-shielding film 15 is set so that the exposure light transmittance has a desired value for the third semi-transparent portion 13C. .

Therefore, the photomask 10 according to the present embodiment is a five-tone photomask having different exposure light transmittances in five stages. For example, the light transmittances of the first to third semi-transparent portions 13A to 13C can be about 20%, 40%, and 60%, respectively, when the translucent portion is 100%. In addition, the pattern shape of the light-shielding part 11, the translucent part 12, and the semi-transparent parts 13A-13C shown in FIG. 1 is an example to the last. Of course, referring to the above embodiment, if only one of the second and third semi-transparent portions is adopted, it can be used as a four-tone photomask having different exposure light transmittances in four stages. . On the other hand, if the line width of the fine pattern in the second semi-transparent portion 13B and the third semi-transparent portion 13C is changed depending on the region, it is of course possible to manufacture a multi-tone photomask. It is also possible to form a semi-translucent portion in which the light transmittance is inclined by continuously changing the line width.

When the pattern transfer to the transfer target 20 is performed using the multi-tone photomask 10 as described above, the exposure light is not substantially transmitted through the light shielding unit 11 and the exposure light is transmitted through the light transmitting unit 12. And the exposure light is reduced in the first to third semi-transparent portions 13A to 13C according to the respective light transmittances. Therefore, the resist film (here, positive photoresist film) applied on the transfer target 20 has the largest thickness in the portion corresponding to the light-shielding portion 11 when developed after pattern transfer. Moreover, in the part corresponding to the said 1st-3rd semi-transparent part 13A-13C, all become thinner than the film thickness of the part corresponding to the light-shielding part 11, but according to the light transmittance of each semi-transparent part. The film thickness gradually decreases. Further, there is no film in the portion corresponding to the light transmitting portion 12. As a result, resist patterns 23 having different film thicknesses in five stages (one of which has no film) are formed. That is, five transfer patterns having different resist residual film values can be transferred onto the transfer target 20 using a single multi-tone photomask 10. In the case where a negative photoresist is used, it is possible to design in consideration of the reverse of the resist film thickness. .

Then, by using the resist patterns 23 having different thicknesses shown in FIG. 1 to sequentially etch each film of the laminated film 22 in the transfer target 20, for example, a conventional photomask for manufacturing a TFT substrate. The process for four sheets is carried out, and the number of masks can be greatly reduced as compared with the prior art.
The case where the multi-tone photomask 10 of this embodiment is used as a five-tone photomask has been described above. However, the present invention is not limited to this, and the photomask configuration is five-tone as follows. There is an advantage that it can be effectively used as a photomask of 3 gradations or 4 gradations.

In general, a multi-tone photomask to which the present invention belongs (a photomask having three or more tones having a semi-transparent portion in addition to a light-shielding portion and a light-transmitting portion) has a desired remaining film value on a transfer target. In order to obtain a resist pattern, the exposure light transmittance of the semi-translucent portion is selected and determined. The transmittance is defined using the transmittance of the semi-transmissive film when the transmittance of the light transmitting portion (that is, the portion where the transparent substrate is exposed) is 100%. This is not a problem when specifying the transmittance of a pattern of a wide area above a certain level, but strictly speaking, for a pattern with a size of a certain degree or less, exposure that contributes to actual pattern transfer. The amount of light is not accurately reflected. Since this is due to diffraction of exposure light, this tendency becomes more prominent as the exposure light wavelength becomes longer as the pattern becomes smaller. However, the present situation is that the change in transmittance with respect to light sources having different pattern dimensions and spectral characteristics is not accurately taken into consideration.

  Specifically, when a pattern shape including a very narrow width and a pattern shape of a relatively wide region are present in the semi-transparent portion, the semi-transparent portion has a resist film on the transfer target, Where a constant residual film value should always be given, a resist pattern with a different residual film value is formed due to the pattern shape, and if the residual film value varies beyond the desired tolerance, There is a problem that it becomes an unstable factor in device manufacturing.

  For example, a multi-tone photomask for a thin film transistor is often used in which a region corresponding to a channel portion is a semi-translucent portion and a region corresponding to a source and a drain adjacent to each other is formed by a light shielding portion. The This photomask is normally exposed using exposure light in the wavelength band of i-line to g-line, but as the size (width) of the channel portion becomes smaller, the boundary with the adjacent light-shielding portion is the actual exposure. The exposure light transmittance of the channel portion is lower than the transmittance of the semi-transmissive film. FIG. 7 shows the pattern of the semi-transparent part B sandwiched between the light-shielding parts A (FIG. 1 (1)) and the light intensity distribution of the transmitted light of the semi-transparent part B (FIG. 2). FIG. 6A shows the case where the width of the semi-translucent region is 4 μm as an example, and FIG. 6B shows the case where the width is 2 μm. That is, as shown in FIGS. 7A and 7B, the light intensity distribution of the transmitted light of the semi-transparent part B sandwiched between the light-shielding parts A is as follows. The whole is lowered and the peak is lowered. In other words, the transmittance that actually contributes to the exposure is relatively low for the pattern having the narrow width region, while the transmittance that contributes to the actual exposure is the pattern that has the relatively wide line width. Relatively high. For example, as shown in FIG. 8, when the channel width is 5 μm or less, the transmissivity of light contributing to actual exposure in the semi-transparent portion having a width corresponding to the channel width decreases.

Therefore, the transmissivity of the semi-transparent part having a certain size is distinguished from the transmissivity inherent to the film, and the actual amount of exposure light transmission is determined as the effective transmissivity in the ratio of the transmissivity of the translucent part. It is necessary to grasp.
On the other hand, the transmittance specific to the film is determined by the composition and film thickness of the film in a sufficiently wide region where the film is formed on the transparent substrate. A sufficiently wide region refers to a region where the effective transmittance does not substantially change due to a change in the size of the region. In FIG. 8, the transmittance of the region is represented by the peak value of the light intensity distribution of the transmitted light of the semi-transparent portion B. The transmittance of this portion has a correlation with the resist residual film value on the transfer target when the multi-tone mask is used for exposure.

Therefore, by changing the light transmittance of the portion according to the pattern shape of the semi-translucent portion, the remaining film value of the resist film of the semi-transparent portion can be made almost the same regardless of the pattern shape.
For example, according to the present embodiment, a multi-tone photomask having four or five gradations can be obtained as a mask configuration. That is, in addition to the light transmitting portion and the light shielding portion, a semi-light transmitting portion having two or three different light transmittances can be obtained. With these three types of semi-transparent portions, resist patterns having different resist residual film values may be formed on the transfer target. However, on the other hand, the three types of semi-transparent portions have different pattern dimensions on the transfer target (therefore, if the semi-transparent portions having the same light transmittance are used, the resist remaining film value formed However, a resist pattern having a certain resist residual film value can be formed. In other words, each of the three semi-transparent portions 13A, 13B, and 13C is formed by a portion formed by a semi-transparent film, a portion formed by a fine pattern of the semi-transparent film, and a fine pattern of a light shielding film. The semi-transparent part is formed with the same effective transmittance as a result of pattern transfer, although it has three different light transmittances depending on the pattern shape of the semi-translucent part. Also good. In this case, the photomask of this embodiment is used as a three-tone photomask.

  Of course, of the three types of semi-transparent portions 13A to 13C, two types may be used for patterns having different shapes having the same effective transmittance, and the remaining one type may be used for patterns having different effective transmittances. good. In this case, the photomask of this embodiment is used as a four-tone photomask.

As described above, since the multi-tone photomask 10 of the present embodiment can have four or five different light transmittances, it can be used as a purely five-tone photomask. For example, when a resist pattern having almost the same remaining film value is formed regardless of the pattern shape of the semi-translucent portion, it can be used as a photomask having three or four gradations. . In addition, in the present embodiment, the three semi-transparent portions 13A, 13B, and 13C each have a portion formed by a semi-transparent film, a portion formed by a fine pattern of the semi-transparent film, and a fine portion of the light-shielding film. Since it is composed of a part formed by a pattern, for example, the semi-transparent portion 13B is formed by forming a fine pattern using the same semi-transparent film as the semi-transparent portion 13A, and the semi-transparent portion 13C is It can be easily obtained by forming a fine pattern using the same light shielding film as the light shielding part 11. For example, compared with the case where three types of semi-transparent portions are formed by changing the material and film thickness of the semi-transparent film, the present invention has a greater range and accuracy in which the transmissivity of the semi-transparent portion can be adjusted. Is simple and has great manufacturing advantages. Accordingly, the multi-tone photomask of the present invention is suitable not only when it is effectively used as a five-tone photomask but also when used effectively as a three-tone or four-tone photomask. It is.

In the above, a photomask having three types of semi-translucent portions 13A to 13C in addition to the light-shielding portion 11 and the light-transmitting portion 12 is shown. However, the present invention is not limited to this, and for example, the light-shielding portion. 11 and the translucent part 12, a photomask having a semi-transparent part 13 A made of a semi-transparent film 16 and a semi-transparent part 13 B made of a fine pattern of the semi-transparent film 16, or the light-shielding part 11 And a translucent portion 12, a photomask having a semi-transparent portion 13 A made of a semi-transparent film 16 and a semi-transparent portion 13 C made of a fine pattern of a laminated film of the semi-transparent film 16 and the light shielding film 15. It is good. In this case, it can be effectively used as a photomask of 4 gradations or 3 gradations.

Next, a method for manufacturing the multi-tone photomask 10 according to the present embodiment will be described. FIG. 2 is a cross-sectional view showing the manufacturing steps of the multi-tone photomask 10 of the first embodiment in the order of steps.
As shown in FIG. 2A, the photomask blank to be used includes a semi-transparent film 16 and a light shielding film 15 made of a laminate of a light shielding layer 15a and an antireflection layer 15b on a transparent substrate 14 such as a glass substrate. It is formed in order. However, for the semi-transparent film 16 and the light shielding film 15, a combination of materials having etching selectivity with respect to an etchant used in the etching process is selected. Therefore, as the light shielding layer 15a, for example, chromium or a compound thereof (for example, CrN, CrO, CrC, etc.) is preferably cited. Can be mentioned. Here, a Cr light shielding layer and a CrO antireflection layer were used. Further, as the semi-transparent film 16, for example, metal silicide, in particular, molybdenum silicide compound (MoSix, MoSi nitride, oxide, oxynitride, carbide, etc.) is preferable. The semi-transparent film 16 preferably has a transmission amount of about 10 to 80%, preferably about 20 to 70% with respect to the transmission amount of exposure light of the transparent substrate 14 (translucent portion). Here, a MoSix film having a film transmittance of 40% (when the light transmitting portion is 100%) was used.

First, a resist is applied on the photomask blank to form a resist film, and a first drawing is performed. In this embodiment, for example, laser light is used. A positive photoresist is used as the resist. Then, a first pattern 30 is formed on the resist film by drawing a predetermined pattern and performing development after the drawing (see FIG. 2B). The first resist pattern 30 covers the regions of the light-shielding portion 11 and the first semi-transparent portion 13A of the photomask to be manufactured, and has a predetermined fine pattern in the regions of the second and third semi-transparent portions 13B and 13C. A resist pattern for forming the film.
The fine pattern of the semi-transparent film 16 constituting the second semi-transparent portion 13B of the photomask and the laminated film of the semi-transparent film 16 and the light shielding film 15 constituting the third semi-transparent portion 13C. Each of the fine patterns is a fine pattern that is below the resolution limit under the exposure conditions using a photomask, and the exposure light transmittance of each of the first and second semi-transparent portions 13A and 13B has a desired value. As described above, the transmissivity of the semitranslucent film (specific transmissivity as a film, that is, depending on the film material and film thickness) is set, and each of the second and third translucent parts 13B and 13C is set. Each line width of the fine pattern is set so that the exposure light transmittance has a desired value.

  Next, by using the first resist pattern 30 as an etching mask, the light shielding film 15 formed by stacking the light shielding layer 15a and the antireflection layer 15b is etched to form a light shielding film pattern (see FIG. 2C). When the light shielding film 15 mainly composed of chromium is used, the etching means can be either dry etching or wet etching. For example, in the case of a large-sized photomask used for manufacturing a large liquid crystal display panel, wet etching is used. Is preferred. In wet etching, for example, ceric ammonium nitrate is used as an etchant. The light shielding film 15 and the semi-transparent film 16 below the light shielding film 15 are preferably formed of materials having etching selectivity with respect to a predetermined etchant. In this case, the semi-transparent film 16 is hardly etched when the light shielding film 15 is etched.

After the remaining first resist pattern 30 is removed (see FIG. 2D) (or may be removed after the next semi-transparent film 16 is etched), the light-shielding film pattern (photo A light shielding film pattern 15A corresponding to the light shielding portion 11 and the first semi-transparent portion 13A of the mask, and a light shielding film pattern corresponding to a predetermined fine pattern formed in the regions of the second and third semi-transparent portions 13B and 13C. 15B) is used as a mask to etch the lower semi-transparent film 16 (see FIG. 2E). For example, when the translucent film 16 mainly composed of a molybdenum silicide compound is used, either dry etching or wet etching can be used as an etching means. In wet etching, for example, ammonium hydrogen fluoride is mainly used as an etching solution. Use ingredients. Since the light shielding film 15 has etching selectivity with respect to the etching conditions of the semi-transparent film 16, the same line width as the light shielding film pattern 15B formed in the regions of the second and third semi-transparent portions 13B and 13C. A fine pattern of the semi-transparent film 16 is also formed with (CD) accuracy.

Next, the same resist film as described above is formed again on the entire surface, and a second drawing is performed. That is, a second resist pattern 31 is formed by drawing a predetermined pattern on the resist film and performing development after the drawing (see FIG. 2F). The second resist pattern 31 covers a region of the light-shielding portion 11 of the photomask to be manufactured, and a third semi-transparent portion in which a fine pattern of a laminated film of the semi-transparent film 16 and the light-shielding film 15 is formed. It is formed so as to cover the area of 13C.

Next, using the second resist pattern 31 as a mask, the fine pattern of the light shielding film 15 on the exposed semi-transparent portion 13A region and the light shielding film 15 on the second semi-transparent portion 13B region are simultaneously etched (FIG. 2 (g)). The etching conditions in this case may be the same as the above-described step (c). The semi-transparent film 16 under the light-shielding film 15 has etching selectivity with respect to the etching conditions of the light-shielding film 15, so that the semi-transparent film 16 is hardly etched. Therefore, for example, the CD accuracy of the fine pattern of the semi-transparent film 16 formed in the second semi-transparent portion 13B by the etching is maintained well.

Then, the remaining second resist pattern 31 is removed. Thus, on the transparent substrate 14, the light-shielding portion 11 formed by stacking the light-transmitting film 16 and the light-shielding film 15 including the light-shielding layer 15a and the antireflection layer 15b, the light-transmitting portion 12 from which the transparent substrate 14 is exposed, and 13A of 1st semi-transparent parts which consist of the said semi-transparent film 16, and 2nd semi-transparent part 13B which consists of the fine pattern 17 below a resolution limit on the exposure conditions formed with the same semi-transparent film 16 as the above. And a mask pattern having a third semi-transparent portion 13 </ b> C composed of a fine pattern 18 below the resolution limit under the exposure conditions formed by the laminated film of the semi-transparent film 16 and the light-shielding film 15 as the light-shielding portion. The formed five-tone photomask 10 having different exposure light transmittances in five stages is completed (see FIG. 2H). Here, if the line width of the fine pattern in the second semi-transparent portion 13B and the third semi-transparent portion 13C is changed depending on the region, it is also possible to manufacture a multi-tone photomask. . In that case, the manufacturing process can be carried out as described above.

As described above, according to the method for manufacturing a multi-tone photomask of the present embodiment, a combination of a light-shielding film and a semi-transparent film is used, and a semi-transparent portion made of a semi-transparent film is formed by photolithography. The semi-transparent portion can be formed with high accuracy by the micro-pattern of the semi-transparent film and / or the micro-pattern of the light-shielding film, and the multi-tone photomask can be formed efficiently and the probability of defect occurrence. Since it can be manufactured by a simple and low process, the merit in mass production is great.
In addition, when pattern transfer using the multi-tone photomask according to the present invention as shown in FIG. 1 is performed, high-precision multi-tone transfer having a desired resist residual film value on the transfer target is performed. A pattern can be formed.
In the above description, the light shielding film 15 and the semi-transparent film 16 are films having etching selectivity with each other. On the other hand, if the light shielding film 15 and the semi-transparent film 16 do not have sufficient etching selectivity, an etching stopper film can be introduced between them. In this case, both the light shielding film 15 and the semi-transparent film 16 can be made of chromium or a chromium compound, and molybdenum silicide, silicon dioxide, or the like can be used for the etching stopper film. The same applies to the following second embodiment.

[Second Embodiment]
FIG. 3 is a cross-sectional view showing the manufacturing steps of the multi-tone photomask according to the second embodiment in the order of steps. In addition, the same code | symbol is attached | subjected to the location equivalent to FIG.1 and FIG.2 which shows the above-mentioned 1st Embodiment.
The photomask blank used in the present embodiment and the manufacturing process using the photomask blank are exactly the same as those in the first embodiment described above, but in the present embodiment, the second resist pattern 31 described above is used. In the step of forming (see FIG. 3F), the second resist pattern 31 covering the region of the third semi-transparent portion 13C where the fine pattern of the laminated film of the semi-transparent film 16 and the light-shielding film 15 is formed It is formed wider than the region width (see the portion indicated by reference numeral 31a in FIG. 3 (f)). As a result, if a misalignment with respect to the drawing pattern on the first surface occurs at the time of the second drawing for forming the second resist pattern 31, the influence of the misalignment can be prevented, and the CD accuracy of the fine pattern is good. Maintained. Therefore, it is possible to prevent the transmissivity of the semi-translucent portion 13C from deviating beyond the allowable range. Here, the above-described wide resist pattern is formed by processing the pattern data of the second resist pattern 31. In determining the margin width to be enlarged at this time, an assumed misalignment amount is set. It is preferable to set the resist pattern width so that an integer number of fine patterns of the laminated film are surely included when added (as shown in FIG. 3F).

Also by the manufacturing method of the multi-tone photomask of the present embodiment, a combination of a light-shielding film and a semi-transparent film is used, and a semi-transparent portion made of a semi-transparent film and a semi-transparent film are formed by photolithography. The semi-transparent portion can be accurately formed together with the fine pattern and / or the fine pattern of the light-shielding film, and the multi-tone photomask can be formed efficiently and with a low probability of occurrence of defects. Can be manufactured by.
The multi-tone mask of the present invention shown in FIG. 2 can be manufactured as shown in FIG. 4 by changing the manufacturing process. Here, in FIG. 2 (or FIG. 3), the semi-transparent film is etched using the first resist pattern (or the light-shielding film pattern etched using the first resist pattern as a mask), whereas only the light-shielding film is etched. Further, the second resist pattern is used as a mask in that the light shielding film and the semi-transparent film are etched instead of etching the light shielding film.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 5 is a cross-sectional view showing the manufacturing steps of the multi-tone photomask 10 according to the third embodiment in the order of steps. In addition, the same code | symbol is attached | subjected to the location equivalent to FIG.1 and FIG.2 which shows the above-mentioned 1st Embodiment.
As shown in FIG. 5A, a photomask blank to be used has a light shielding film 15 formed of a laminate of a light shielding layer 15a and an antireflection layer 15b on a transparent substrate 14 such as a glass substrate. As the light shielding layer 15a, for example, chromium or a compound thereof (for example, CrN, CrO, CrC, etc.) is preferably mentioned, and as the antireflection layer 15b, a chromium compound (for example, CrN, CrO, CrC, etc.) can be mentioned. .

First, a resist is applied on the photomask blank to form a resist film, and a first drawing is performed. A positive photoresist is used as the resist. Then, a predetermined pattern is drawn on the resist film, and development is performed after the drawing, thereby forming the first resist pattern 32 (see FIG. 5B).
The first resist pattern 32 covers the regions of the light shielding part 11, the light transmitting part 12, and the third semi-transparent part 13C of the photomask to be manufactured, and has a predetermined fine pattern in the area of the second semi-transparent part 13B. A resist pattern for forming the film.

  Next, by using the first resist pattern 32 as an etching mask, the light shielding film 15 formed by stacking the light shielding layer 15a and the antireflection layer 15b is etched to form a light shielding film pattern (see FIG. 5C). When the light shielding film 15 mainly composed of chromium is used, the etching means can be either dry etching or wet etching. For example, in wet etching suitable for manufacturing a large size photomask, Ceric ammonium nitrate is used.

After removing the remaining first resist pattern 32 (see FIG. 5D), a semi-transparent film 16 is formed on the entire surface of the substrate including the patterned light shielding film 15 (see FIG. 5E).
As the semi-transparent film 16, for example, a metal silicide compound, in particular, a molybdenum silicide compound (MoSix, MoSi nitride, oxide, oxynitride, carbide, etc.) is preferably mentioned as in the above-described embodiment. . In the present embodiment, the semi-transparent film 16 is not particularly required to have etching selectivity with respect to the light shielding film 15, and therefore, for example, chromium or a chromium-based compound can be used as in the case of the light shielding film. The chromium-based compounds include chromium oxide (CrOx), chromium nitride (CrNx), chromium carbide (CrCx), chromium oxynitride (CrOxN), chromium fluoride (CrFx), and those containing carbon and hydrogen. The semi-transparent film 16 preferably has a transmission amount of about 10 to 80%, preferably about 20 to 70% with respect to the transmission amount of exposure light of the transparent substrate 14 (translucent portion).

Next, the same resist film as described above is formed again on the entire surface, and a second drawing is performed. That is, a second resist pattern 33 is formed by drawing a predetermined pattern on the resist film and performing development after the drawing (see FIG. 5F). The second resist pattern 33 covers the regions of the light-shielding portion 11 and the first semi-transparent portion 13A of the photomask to be manufactured, and is semi-transparent among the fine patterns formed in the region of the second semi-transparent portion 13B. It includes a resist pattern that covers the fine pattern of the optical film 16 and further forms a predetermined fine pattern in the region of the third semi-transparent portion 13C. Here, in the drawing process for forming a resist pattern that covers the fine pattern of the semi-transparent film 16 among the fine patterns formed in the region of the second semi-transmissive portion 13B, the position relative to the first drawing is described above. Matching is important. When the misalignment occurs, there is a possibility that the light shielding film may remain in the semi-transparent film 13B that should be formed by the patterned semi-transparent film. In addition, it can be said that the manufacturing method in the said 1st, 2nd embodiment is excellent at the point which does not have the subject of this alignment.

Next, using the second resist pattern 33 as a mask, the semi-transparent film 16 on the exposed translucent part 12, the second semi-transparent part 13B, and the third semi-transparent part 13C region and the light shielding film 15 therebelow. Are continuously etched (see FIG. 5G).

Then, the remaining second resist pattern 33 is removed. Thus, on the transparent substrate 14, the light-shielding portion 11 formed by stacking the light-shielding film 15 and the semi-transparent film 16 including the light-shielding layer 15a and the antireflection layer 15b, the light-transmitting portion 12 from which the transparent substrate 14 is exposed, and the above-described half A first semi-transparent portion 13A made of a translucent film 16, and a second semi-transparent portion 13B made of a fine pattern 17 below the resolution limit under the exposure conditions formed by the same semi-transparent film 16 as described above, A mask pattern having a third semi-transparent portion 13 </ b> C made of a fine pattern 18 below the resolution limit under an exposure condition formed by a laminated film of the same light-shielding film 15 and semi-transparent film 16 as the light-shielding portion is formed. In addition, a photomask 10 having five gradations with different exposure light transmittances in five stages is completed (see FIG. 5H).

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 6 is a cross-sectional view showing the manufacturing steps of the multi-tone photomask 10 according to the fourth embodiment in the order of steps. In addition, the same code | symbol is attached | subjected to the location equivalent to FIG.1, FIG.2, FIG.3 which shows the above-mentioned 1st Embodiment.
The photomask blank used in FIG. 6A is similar to FIG. 5A, in which a light shielding film 15 composed of a laminate of a light shielding layer 15a and an antireflection layer 15b is formed on a transparent substrate 14 such as a glass substrate. .

First, a resist is applied on the photomask blank to form a resist film, and a first drawing is performed. A positive photoresist is used as the resist. Then, a predetermined pattern is drawn on the resist film, and development is performed after the drawing, thereby forming a first resist pattern 34 (see FIG. 6B).
The first resist pattern 34 includes a resist pattern for covering the region of the light-shielding portion 11 of the manufactured photomask and forming a predetermined fine pattern in the region of the third semi-transparent portion 13C.

  Next, by using the first resist pattern 34 as an etching mask, the light shielding film 15 formed by laminating the light shielding layer 15a and the antireflection layer 15b is etched to form a light shielding film pattern (see FIG. 6C). When the light shielding film 15 mainly composed of chromium is used, the etching means can be either dry etching or wet etching. For example, in wet etching suitable for manufacturing a large size photomask, Ceric ammonium nitrate is used.

After the remaining first resist pattern 34 is removed (see FIG. 6D), a semi-transparent film 16 is formed on the entire surface of the substrate including the patterned light shielding film 15 (see FIG. 6E).
As the semi-transparent film 16, for example, the same film as in the third embodiment is used. The semi-transparent film 16 preferably has a transmission amount of about 10 to 80%, preferably about 20 to 70% with respect to the transmission amount of exposure light of the transparent substrate 14 (translucent portion).

Next, the same resist film as described above is formed again on the entire surface, and a second drawing is performed. That is, a second resist pattern 35 is formed by drawing a predetermined pattern on the resist film and performing development after the drawing (see FIG. 6F). The second resist pattern 35 covers the regions of the light shielding part 11 and the first semi-transparent part 13A of the photomask to be manufactured, and among the fine patterns formed in the region of the third semi-transparent part 13C, 15 and a semi-transparent film 16 including a resist pattern for covering the fine pattern and further forming a predetermined fine pattern in the region of the second semi-transparent portion 13B.
Next, using the second resist pattern 35 as a mask, the semi-transparent film 16 on the exposed regions of the translucent part 12, the second semi-transparent part 13B, and the third semi-transparent part 13C is etched (FIG. 6 ( g)).

Then, the remaining second resist pattern 35 is removed. Thus, on the transparent substrate 14, the light-shielding portion 11 formed by stacking the light-shielding film 15 and the semi-transparent film 16 including the light-shielding layer 15a and the antireflection layer 15b, the light-transmitting portion 12 from which the transparent substrate 14 is exposed, and the above-described half A first semi-transparent portion 13A made of a translucent film 16, and a second semi-transparent portion 13B made of a fine pattern 17 below the resolution limit under the exposure conditions formed by the same semi-transparent film 16 as described above, A mask pattern having a third semi-transparent portion 13 </ b> C made of a fine pattern 18 below the resolution limit under an exposure condition formed by a laminated film of the same light-shielding film 15 and semi-transparent film 16 as the light-shielding portion is formed. In addition, a photomask 10 having five gradations with different exposure light transmittances in five stages is completed (see FIG. 6H).

As described above, also in the manufacturing method of the multi-tone photomask according to the present embodiment, by using a combination of a light-shielding film and a semi-transparent film, by a photolithography method, a semi-transparent portion made of a semi-transparent film, The semi-transparent part formed by the micro-pattern of the semi-transparent film and the micro-pattern of the light-shielding film can be formed together with high accuracy, and the multi-tone photomask is efficient and simple with a low probability of occurrence of defects. It can be manufactured by a simple process.

Note that the photomask of the present invention may be manufactured using any of the above embodiments. When these are compared, in the third and fourth embodiments, a fine pattern is drawn on the resist on the semi-transparent film at the time of the second drawing. It is a semi-transparent film having various transmittances according to the above. Therefore, the film quality and film thickness of the semi-transparent film are different from each other, and therefore the intensity of reflected light is also different. Therefore, when drawing a fine pattern, it is necessary to control the line width, that is, the amount of exposure light very precisely. is there. On the other hand, in the first and second embodiments, drawing for forming a fine pattern is performed on a light shielding film (an antireflection film), so that a predetermined line width can be realized under certain drawing conditions. Therefore, there is an advantage that it is easy to produce a multi-tone photomask with more stable transmittance.
Further, the molybdenum silicide semi-transparent film used in the first and second embodiments has a thin film thickness (about 100 to 900 mm) for obtaining a transmittance of 20 to 70%, and CD by side etching. The effect of the present invention is particularly remarkable because there is very little concern about deterioration.
In addition, the manufacturing method of the multi-tone photomask of this invention is not limited to what was illustrated above.

It is sectional drawing for demonstrating 1st Embodiment of the multi-tone photomask which concerns on this invention, and the pattern transfer method using the said multi-tone photomask. It is sectional drawing which shows the manufacturing process of the multi-tone photomask which concerns on the said 1st Embodiment in process order. It is sectional drawing which shows the manufacturing process of the multi-tone photomask which concerns on 2nd Embodiment in order of a process. It is sectional drawing which shows the other manufacturing process of the multi-tone photomask concerning 2nd Embodiment to process order. It is sectional drawing which shows the manufacturing process of the multi-tone photomask which concerns on 3rd Embodiment in process order. It is sectional drawing which shows the manufacturing process of the multi-tone photomask which concerns on 4th Embodiment in order of a process. The pattern of the semi-translucent part B sandwiched between the light-shielding parts A (FIG. 1A) and the light intensity distribution of the transmitted light of the semi-transparent part B (FIG. 2B) are shown. ) Shows a case where the width of the semi-translucent region is 4 μm, and FIG. It is a figure which shows the relationship between the transmittance | permeability of exposure light in the semi-transmission part of the width | variety corresponding to the channel width and this channel width.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Multi-gradation photomask 11 Light-shielding part 12 Light-transmitting part 13A 1st semi-light-transmitting part 13B 2nd semi-light-transmitting part 13C 3rd semi-light-transmitting part 14 Transparent substrate 15 Light-shielding film 16 Semi-light-transmitting film 17 Semi-light-transmitting film Fine pattern 18 Light-shielding film fine pattern 20 Transfer object 23 Resist pattern

Claims (13)

On the transparent substrate, has a mask pattern consisting of a light-shielding part, a light-transmitting part, and a semi-light-transmitting part that reduces the exposure light transmittance by a predetermined amount,
The light shielding part is formed by at least a light shielding film formed on the transparent substrate, the light transmitting part is formed by the exposed transparent substrate, and the semi-light transmitting part is formed on the transparent substrate. A first semi-transparent portion made of a semi-translucent film, and a second semi-transparent portion in which a fine pattern having a line width less than a resolution limit under an exposure condition is formed on the transparent substrate on the transparent substrate. A multi-tone photomask comprising an optical part. On the transparent substrate, has a mask pattern consisting of a light-shielding part, a light-transmitting part, and a semi-light-transmitting part that reduces the exposure light transmittance by a predetermined amount,
The light shielding part is formed by at least a light shielding film formed on the transparent substrate, the light transmitting part is formed by the exposed transparent substrate, and the semi-light transmitting part is formed on the transparent substrate. A first semi-transparent portion made of a semi-transparent film, and a third semi-transparent portion in which a fine pattern having a line width less than a resolution limit under an exposure condition is formed on at least the light-shielding film on the transparent substrate. And a multi-tone photomask characterized by comprising: On the transparent substrate, has a mask pattern consisting of a light-shielding part, a light-transmitting part, and a semi-light-transmitting part that reduces the exposure light transmittance by a predetermined amount,
The light shielding part is formed by at least a light shielding film formed on the transparent substrate, the light transmitting part is formed by the exposed transparent substrate, and the semi-light transmitting part is formed on the transparent substrate. A first semi-transparent portion made of a semi-translucent film, and a second semi-transparent portion in which a fine pattern having a line width less than a resolution limit under an exposure condition is formed on the transparent substrate on the transparent substrate. An optical part, and a third semi-transparent part in which a fine pattern having a line width less than or equal to a resolution limit under an exposure condition is formed on at least the light-shielding film on the transparent substrate. Multi-tone photomask.   4. The multi-tone photo according to claim 1, wherein the light shielding film is made of a material containing chromium as a main component, and the semi-transparent film is made of a material containing metal silicide as a main component. mask.   4. The light shielding portion according to claim 1, wherein at least the semi-transparent film and the light shielding film are laminated, and an etching stopper film is provided between the semi-transparent film and the light shielding film. The multi-tone photomask according to any one of the above. A method for producing a multi-tone photomask having a mask pattern comprising a light-shielding portion, a light-transmitting portion, and a semi-light-transmitting portion that reduces exposure light transmittance by a predetermined amount on a transparent substrate,
A step of preparing a photomask blank having a translucent film and a light-shielding film in this order on a transparent substrate;
Drawing and developing a resist film formed on the light-shielding film of the photomask blank to form a predetermined first resist pattern;
Etching the light shielding film using the first resist pattern as a mask to form a light shielding film pattern;
Etching the semi-transparent film using the first resist pattern or the light shielding film pattern as a mask;
Drawing and developing a resist film formed on the entire surface of the substrate including the patterned light-shielding film and the semi-translucent film, and forming a second resist pattern;
Etching the light shielding film exposed using the second resist pattern as a mask,
At least one of the first resist pattern and the second resist pattern includes a fine pattern,
A light shielding portion formed of a semi-transparent film and a light shielding film formed on the transparent substrate;
A transparent portion formed by exposing the transparent substrate;
A semi-transparent portion made of a semi-transparent film formed on the transparent substrate;
On the transparent substrate, a fine pattern of a semi-transparent film having a line width below the resolution limit under exposure conditions and / or a fine pattern of a light-shielding film having a line width below the resolution limit under exposure conditions is formed. A method for producing a multi-tone photomask, comprising: forming a semi-transparent portion.   When forming a semi-transparent portion made of a fine pattern of a light shielding film below the resolution limit under exposure conditions on the transparent substrate, the second resist pattern covering the area where the fine pattern of the light shielding film is formed is the area. The method for manufacturing a multi-tone photomask according to claim 6, wherein the multi-tone photomask is formed wider than the width. A method for producing a multi-tone photomask having a mask pattern comprising a light-shielding portion, a light-transmitting portion, and a semi-light-transmitting portion that reduces exposure light transmittance by a predetermined amount on a transparent substrate,
A step of preparing a photomask blank having a translucent film and a light-shielding film in this order on a transparent substrate;
Drawing and developing a resist film formed on the light-shielding film of the photomask blank to form a predetermined first resist pattern;
Etching the light shielding film using the first resist pattern as a mask to form a light shielding film pattern;
Drawing and developing a resist film formed on the entire surface of the substrate including the patterned light-shielding film and the semi-translucent film to form a predetermined second resist pattern;
Etching the semi-transparent film or the light-shielding film exposed using the second resist pattern as a mask, and a semi-transparent film therebelow.
At least one of the first resist pattern and the second resist pattern includes a fine pattern,
A light shielding portion formed of a semi-transparent film and a light shielding film formed on the transparent substrate;
A transparent portion formed by exposing the transparent substrate;
A semi-transparent portion made of a semi-transparent film formed on the transparent substrate;
A fine pattern of a semi-transparent film having a line width below the resolution limit under exposure conditions and / or a fine pattern of a light-shielding film having a line width below the resolution limit under exposure conditions is formed on the transparent substrate. A method for manufacturing a multi-tone photomask, comprising: forming a semi-transparent portion.   9. The method for manufacturing a multi-tone photomask according to claim 6, wherein the light shielding film and the semi-transparent film are made of a material having etching selectivity.   10. The method for manufacturing a multi-tone photomask according to claim 9, wherein the light shielding film is made of a material containing chromium as a main component, and the semi-transparent film is made of a material containing metal silicide as a main component.   9. The method for manufacturing a multi-tone photomask according to claim 6, further comprising an etching stopper film between the light shielding film and the semi-translucent film. A method for producing a multi-tone photomask having a mask pattern comprising a light-shielding portion, a light-transmitting portion, and a semi-light-transmitting portion that reduces exposure light transmittance by a predetermined amount on a transparent substrate,
Preparing a photomask blank having a light shielding film on a transparent substrate;
Drawing and developing a resist film formed on the light-shielding film of the photomask blank to form a first resist pattern;
Etching the light shielding film using the first resist pattern as a mask to form a light shielding film pattern;
Forming a semi-transparent film on the entire surface of the substrate including the patterned light-shielding film after removing the first resist pattern;
Drawing and developing a resist film formed on the semi-translucent film to form a predetermined second resist pattern;
Etching the semi-transparent film exposed using the second resist pattern as a mask, or the semi-transparent film and the light-shielding film in order,
At least one of the first resist pattern and the second resist pattern includes a fine pattern,
A light-shielding portion made of a light-shielding film and a semi-transparent film formed on the transparent substrate, a light-transmitting portion formed by exposing the transparent substrate, and a semi-transparent made of a semi-transparent film formed on the transparent substrate A light pattern and a light-shielding film having a fine pattern of a semi-transparent film having a line width less than a resolution limit under exposure conditions and / or a line width less than a resolution limit under exposure conditions formed on the transparent substrate A method for producing a multi-tone photomask, comprising: forming a semi-transparent portion having a fine pattern. Using the multi-tone photomask according to any one of claims 1 to 5 or the multi-tone photomask according to any one of claims 6 to 12 to irradiate a transfer material with exposure light. A pattern transfer method comprising: an exposing step for forming a multi-tone transfer pattern on a transfer target.

Images