JP2017062462A - Method of manufacturing photomask, photomask, and method of manufacturing display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a photomask which is finer and has both higher CD accuracy and transmittance accuracy.SOLUTION: The method of manufacturing a photomask which is provided with a transfer pattern including a translucent part, a first transmission control part, and a second transmission control part on a transparent substrate includes: a step of preparing a photomask blank in which a first thin film having a predetermined exposure light transmittance is formed on the transparent substrate; a first patterning step of etching the first thin film to form a first thin film pattern; and a second patterning step of forming a second thin film on the transparent substrate on which the first thin film pattern is formed, and etching the second thin film to form a second thin film pattern. In the second patterning step, only the second thin film is etched.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a multi-tone photomask useful for manufacturing a display device represented by a liquid crystal panel or an organic EL panel, a manufacturing method thereof, and a manufacturing method of a display device using the multi-tone photomask. .

  In recent years, display devices represented by liquid crystal panels and organic EL panels have been required to be further miniaturized, and the pattern of photomasks for manufacturing these devices has a tendency toward miniaturization. It has become prominent. In particular, the reason why the display device is desired to be miniaturized is advantageous not only from the viewpoint of energy saving, but also from the advancement of image quality such as increase in pixel density, improvement in display brightness, and improvement in reaction speed. It has something to do with it. Along with such a trend of miniaturization, quality requirements for photomasks are also increasing.

Conventionally, a multi-tone photomask (gray-tone mask) having a transfer pattern formed by patterning a light-shielding film and a semi-transparent film formed on a transparent substrate is known. This multi-tone photomask is usefully used in manufacturing a display device or the like.
For example, the following Patent Document 1 describes a halftone film type gray tone mask and a manufacturing method thereof.

JP 2005-257712 A

  This multi-tone photomask has three or more portions with different light transmittances, such as a light shielding portion, a light transmitting portion, and a semi-light transmitting portion, on a transfer pattern. A resist pattern having a plurality of remaining film thicknesses is to be formed. When this resist pattern is used as an etching mask for processing a thin film formed on a transfer object, it functions as an etching mask having a different shape by reducing the resist pattern after the first etching. Since the second etching can be performed, the multi-tone photomask can be said to be a photomask having a function corresponding to a plurality of photomasks. For this reason, it is possible to reduce the number of photomasks that are mainly necessary for manufacturing a display device, which contributes to an improvement in production efficiency.

  Since the multi-tone photomask has a semi-transparent part using a semi-transparent film that partially transmits exposure light in addition to the light-shielding part and the light-transmitting part, the light transmittance and transmitted light of this part are included. By appropriately controlling the phase characteristics and the like, the partial thickness of the resist pattern formed on the transferred body, the cross-sectional shape thereof, and the like can be changed.

  Further, the multi-tone photomask of Patent Document 1 has a transfer pattern in which a plurality of patterned films (such as a light-shielding film and a semi-transparent film) are stacked. Such a multi-tone photomask is configured by setting a desired transmittance and phase characteristics for light used during exposure, selecting a film material and film thickness suitable for this, and adjusting the film formation conditions. There is an advantage that a multi-tone photomask having desired optical characteristics can be stably designed.

Here, the method described in Patent Document 1 as a conventional technique will be described.
In the method described in Patent Document 1, the gray tone mask 200 shown in FIG. 3I is manufactured by the process shown in FIG. Specifically, first, a photomask blank 100 is prepared in which a light shielding film 102 is formed on a transparent substrate 101 and a positive resist is applied thereon to form a resist film 103 (see FIG. 3A). .

  Then, the image is drawn using a laser drawing machine (first drawing) and developed. As a result, the resist film is removed in the region where the semi-transparent portion is formed (region A in FIG. 3), and the region where the light-shielding portion is formed (region B in FIG. 3) and the region where the transparent portion is formed (C in FIG. In the region, a resist pattern 103a in which the resist film remains is formed (see FIG. 3B).

Next, using the formed resist pattern 103a as a mask, the light shielding film 102 is etched (first etching), and the light shielding film pattern 102a is formed in regions corresponding to the light shielding portion (B region) and the light transmitting portion (C region). It forms (refer FIG.3 (c)). Then, the resist pattern 103a is removed (see FIG. 3D).
A region (A region) corresponding to the semi-translucent portion is defined by the first photolithography process described above.

Next, the semi-transparent film 104 is formed on the entire surface of the substrate with the light shielding film pattern obtained as described above (see FIG. 3E). Thereby, a semi-transparent portion of the A region is formed.
Further, a positive resist is applied to the entire surface of the semi-transparent film 104 to form a resist film 105 (see FIG. 3F), and drawing is performed (second drawing). After development, the resist film 105 is removed in the light transmitting portion (C region), and a resist pattern 105a in which the resist film remains in the light shielding portion (B region) and the semi-light transmitting portion (A region) is formed (FIG. 3 ( g)).

  Using this as a mask, the semi-light-transmitting film 104 and the light-shielding film pattern 102a in the C region to be a light-transmitting portion are removed by etching (second etching) (see FIG. 3H). Here, if the semi-transparent film and the light-shielding film have the same or similar etching characteristics, continuous etching is possible. After the second etching, the resist pattern 105a is removed to complete the gray tone mask 200 (see FIG. 3 (i)).

  By the above-described method, the light-shielding film and the semi-transparent film are patterned by two lithography processes (drawing, developing, and etching), and the gray-tone mask having the light-shielding part, the translucent part, and the semi-transparent part is obtained. Manufactured.

  By the way, display devices equipped with liquid crystal or organic EL are required to be improved in many aspects such as image brightness, sharpness, reaction speed, power consumption reduction, and cost reduction. Yes. Under such circumstances, not only can fine patterns be formed more precisely than in conventional photomasks for manufacturing these display devices, but also patterns can be transferred to a transfer target (such as a panel substrate) at a low cost. Function is required. In addition, the design of required transfer patterns is diversified and complicated.

Under these circumstances, the following new problems have been found by the study of the present inventors.
According to the process of Patent Document 1 described above, the two films of the semi-transparent film and the light-shielding film are removed by etching in one process in the second etching (see FIG. 3H). Here, for example, it is assumed that the light-shielding film is a film containing chromium as a main component and the semi-transparent film is made of a chromium compound. The former time required for etching the light-shielding film is X (for example, 50 seconds), and the latter If the required etching time of the semi-transparent film is Y (for example, 10 seconds), the second etching requires an X + Y etching time (for example, 60 seconds), and the light shielding film or the single film of the semi-transparent film is etched. It takes a long time compared to the case.

  Here, wet etching is applied as an etching method. This is because wet etching can be applied very advantageously to a photomask for manufacturing a display device. This is a relatively large area (one side is, for example, 300 mm or more), and for photomasks for manufacturing display devices in which substrates of various sizes exist, wet etching is more efficient than dry etching that requires a vacuum device. This is because it is very advantageous both in terms of efficiency and efficiency.

  Further, wet etching has a strong isotropic etching property, and etching (side etching) proceeds not only in the depth direction of the film to be etched but also in a direction parallel to the surface of the film to be etched. In general, when a long etching time is required, the in-plane variation of the etching amount tends to increase. Therefore, as the wet etching time becomes longer, the side etching amount increases and the amount of in-plane variation increases. The variation in is also increased. For this reason, when the two films of the semi-transparent film and the light-shielding film are continuously removed by etching in one step by the second etching, the line width or dimension (CD: Critical Dimension) of the formed transfer pattern is formed. The following is used to mean the line width or dimension of the pattern.) Accuracy is likely to deteriorate. That is, the second etching requiring X + Y (seconds) has a problem in this respect. In addition, the amount of etching agent used increases with the length of etching time, and the burden of waste liquid treatment including heavy metals also increases.

  In addition, the present inventors paid attention to the possibility that the following problems may occur when the design of the transfer pattern is complicated or there is a fine dimension (CD) pattern.

  In FIG. 3 (i) showing the method of Patent Document 1, a pattern including a portion where the semi-translucent portion and the light-shielding portion are adjacent to each other is formed. More complicated patterns are included in the photomask transfer pattern. For example, there is a need for a transfer pattern having a portion in which a light-transmitting portion and a semi-light-transmitting portion are adjacent in addition to the adjacent portion.

Therefore, for example, consider a case where the transfer pattern shown in FIG. 3 further includes a portion where the light-transmitting portion and the semi-light-transmitting portion are adjacent (see FIG. 4I). 4F to 4I (second photolithography process) correspond to FIGS. 3F to 3I, respectively.
Here, in the step of FIG. 4 (h) showing the second etching, as in the step of FIG. 3 (h), the semi-transparent film 104 and the light shielding film pattern 102a are continuously etched away (N ) Exists. For this reason, the etching time is long due to the large etching depth, and the side etching amount is also increased according to the etching depth, so that the pattern dimension (CD) to be formed is likely to be distorted. In addition, the distribution of CD errors in the surface tends to be large (see FIG. 4 (h ′)).

  Further, in the step of FIG. 4 (h), the above-described semi-transparent film 104 and the light-shielding film pattern 102a are continuously etched away (N), and only the semi-transparent film 104 is etched away (K). ) Occurs. At this time, it becomes difficult to set the time required for the second etching. This is because when the latter K portion requires an etching time of T (seconds), the former N portion requires an etching time corresponding to T + α (seconds).

  Therefore, in the step of FIG. 4 (h), when the etching of the portion N is actually finished, the etching proceeds excessively in the portion K, and side etching is performed on the semi-transparent film 104 below the resist pattern 105a. Proceeds (see FIG. 4 (h ′)). As a result, the dimension of the formed semi-transparent film pattern 104a is smaller by W (μm) in the portion K than the dimension of the resist pattern 105a, and the pattern dimension (CD) is distorted. The distribution of the CD error tends to be large (see FIG. 4 (i ′)).

  Further, in the semi-transparent film used for such a multi-tone photomask, it is extremely important to manage the light transmittance. In the prior art method of FIG. 3, when the semi-transparent film is formed, However, since a pattern made of a light shielding film already exists on the transparent substrate, it is not easy to measure the light transmittance of the formed semi-transparent film. In particular, since a photomask for manufacturing a display device has a large area (for example, a rectangle having a side of 300 mm or more), a large apparatus (such as a sputtering apparatus) is used for film formation, but the film formation material is uniformly deposited in the surface. There are also difficulties. For example, the film thickness distribution may occur in the surface depending on the relative position with respect to the sputtering target. If this film thickness is accurately measured and this tendency is correctly grasped, the influence can be offset by the second etching (patterning of the light shielding film) in the manufacturing method of the present invention described later. In the conventional method described in 1), there is a problem that it is difficult to accurately measure the transmittance of the semi-transparent film at each position in the plane.

Therefore, it has been found that the conventional method shown in FIG. 3 has a problem when it is desired to manufacture a multi-tone photomask that is finer and has higher CD accuracy and transmittance accuracy.
Accordingly, the present invention provides a photomask manufacturing method, a photomask, and a display device using the photomask capable of manufacturing a multi-tone photomask that is finer and has higher CD accuracy and transmittance accuracy. An object of the present invention is to provide a manufacturing method.

As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by an invention having the following configuration, and have completed the present invention.
That is, the present invention has the following configuration.

(Configuration 1)
A method for manufacturing a photomask comprising a transfer pattern including a light transmission portion, a first transmission control portion, and a second transmission control portion on a transparent substrate, wherein a predetermined exposure light transmittance is provided on the transparent substrate. A step of preparing a photomask blank having a first thin film having a first pattern, a first patterning step of forming a first thin film pattern by etching the first thin film, and the first thin film pattern being formed Forming a second thin film on the transparent substrate, and etching the second thin film to form a second thin film pattern. In the second patterning step, the second patterning step includes: A method for manufacturing a photomask, comprising etching only a thin film.

(Configuration 2)
The translucent part is formed by exposing the surface of the transparent substrate, and the first transmission control unit has a portion where only the first thin film is formed on the transparent substrate, and the second transmission control unit Has a portion where only the second thin film is formed on the transparent substrate. 2. A method of manufacturing a photomask according to Configuration 1, wherein:
(Configuration 3)
3. The method of manufacturing a photomask according to Configuration 1 or 2, wherein the first thin film is made of a material having resistance to an etchant for the second thin film.

(Configuration 4)
The method for manufacturing a photomask according to Configuration 1 or 2, wherein the first thin film is made of a material that is etched by an etchant for the second thin film.
(Configuration 5)
After the first patterning step, before forming the second thin film, the method further includes a step of forming an etching stopper film on the transparent substrate on which the first thin film pattern is formed. The manufacturing method of the photomask as described.

(Configuration 6)
6. The photomask according to claim 5, further comprising a step of removing the etching stopper film of the light transmitting portion or the light transmitting portion and the first transmission control portion after the second patterning step. Production method.
(Configuration 7)
7. The photomask manufacturing method according to any one of Structures 1 to 6, wherein the first thin film is a semi-transparent film that partially transmits exposure light.

(Configuration 8)
The exposure light transmitted through the first transmission control unit has a phase difference φ (degrees) satisfying φ ≦ 90 with respect to a representative wavelength of the exposure light transmitted through the light transmission unit. 7. A method for producing a photomask according to any one of 6 above.
(Configuration 9)
The exposure light transmitted through the first transmission control unit has a phase difference φ (degrees) satisfying φ ≦ 90 with respect to the representative wavelength of the exposure light transmitted through the light transmission unit, and the first transmission control. 7. The photomask manufacturing method according to any one of Configurations 1 to 6, wherein the light transmittance Tf (%) of the portion satisfies 5 ≦ Tf ≦ 60.

(Configuration 10)
The exposure light transmitted through the first transmission control unit has a phase difference φ (degree) satisfying 150 ≦ φ ≦ 210 with respect to a representative wavelength of the exposure light transmitted through the light transmission unit. The manufacturing method of the photomask in any one of 1 thru | or 6.
(Configuration 11)
The exposure light transmitted through the first transmission control unit has a phase difference φ (degree) satisfying 150 ≦ φ ≦ 210 with respect to the representative wavelength of the exposure light transmitted through the light transmitting unit, and light transmittance. 7. The photomask manufacturing method according to any one of Configurations 1 to 6, wherein Tf (%) satisfies 5 ≦ Tf ≦ 60.

(Configuration 12)
12. The method of manufacturing a photomask according to any one of configurations 1 to 11, wherein the second thin film is a semi-transparent film that partially transmits exposure light.
(Configuration 13)
The exposure light transmitted through the second transmission control unit has a phase difference φ (degree) satisfying 0 <φ ≦ 90 with respect to a representative wavelength of the exposure light transmitted through the light transmission unit. A method for producing a photomask according to any one of 1 to 11.

(Configuration 14)
The exposure light transmitted through the second transmission control unit has a phase difference φ (degrees) satisfying 0 <φ ≦ 90 with respect to the representative wavelength of the exposure light transmitted through the light transmission unit, and light transmittance. 12. The photomask manufacturing method according to any one of Configurations 1 to 11, wherein Tf (%) satisfies 5 ≦ Tf ≦ 80.
(Configuration 15)
The exposure light transmitted through the second transmission control unit has a phase difference φ (degrees) satisfying 150 <φ ≦ 210 with respect to the representative wavelength of the exposure light transmitted through the light transmission unit, and light transmittance. Tf (%) satisfy | fills 5 <= Tf <= 60, The manufacturing method of the photomask in any one of the structures 1 thru | or 11 characterized by the above-mentioned.

(Configuration 16)
12. The photomask manufacturing method according to any one of configurations 1 to 11, wherein the second thin film is a light shielding film.
(Configuration 17)
17. The method for manufacturing a photomask according to Configuration 16, wherein a reflection reducing layer for reducing light reflection is provided on a surface portion of the second thin film.

(Configuration 18)
18. The photomask manufacturing method according to any one of configurations 1 to 17, wherein the photomask blank has an additional configuration film and a resist film on the first thin film.
(Configuration 19)
19. The photomask manufacturing method according to Configuration 18, wherein the adhesion between the additional component film and the resist film is higher than the adhesion between the first thin film and the resist film.

(Configuration 20)
Before the first patterning step, there is a preliminary patterning step of etching the additional constituent film to form an additional constituent film pattern, and in the first patterning step, the first constituent film pattern is used as a mask. 20. The method for manufacturing a photomask according to Configuration 18 or 19, wherein the thin film is etched.
(Configuration 21)
21. The photomask manufacturing method according to the structure 20, wherein the additional film pattern is removed after the first patterning process and before the second patterning process.

(Configuration 22)
On the transparent substrate, a transfer pattern including a translucent part, a first transmission control part, and a second transmission control part, including an adjacent part adjacent to the first transmission control part and the second transmission control part is provided. A method for manufacturing a photomask, comprising: preparing a photomask blank in which a first thin film having a predetermined exposure light transmittance is formed on the transparent substrate; and a first region in a region serving as the first transmission control unit. Forming a resist pattern and etching the first thin film to form a first thin film pattern; and forming a second thin film on the transparent substrate on which the first thin film pattern is formed. A film forming process to form, and a second patterning process to form a second thin film pattern by forming a second resist pattern in a region to be the second transmission control unit and etching the second thin film. In the second patterning step, a stacked portion is formed in the adjacent portion where the second resist pattern is stacked with the first thin film pattern, and the second thin film is formed using the second resist pattern. A method of manufacturing a photomask, characterized by etching only the film.

(Configuration 23)
The translucent part is formed by exposing the surface of the transparent substrate, the first transmission control unit includes a portion where only the first thin film is formed on the transparent substrate, and the second transmission control unit includes: The method for manufacturing a photomask according to the structure 22, further comprising a portion where only the second thin film is formed on the transparent substrate.
(Configuration 24)
24. The photomask manufacturing method according to the structure 22 or 23, wherein the width M1 of the stacked portion is in a range of 0.5 to 2 [mu] m.

(Configuration 25)
A photomask having a transfer pattern including a light transmission portion, a first transmission control portion, and a second transmission control portion on a transparent substrate, wherein the transfer pattern has a predetermined exposure light transmittance. The transparent substrate surface is exposed, the first transmission control unit does not form the second thin film on the transparent substrate, and includes the first thin film and the second thin film. A first thin film is formed, and the second transmission control unit includes at least the second thin film formed on the transparent substrate, and a boundary between the first transmission control unit and the second transmission control unit is The photomask is characterized in that the cross section to be etched of the second thin film is formed without forming the cross section of the first thin film to be etched.

(Configuration 26)
The translucent part is formed by exposing the surface of the transparent substrate, and the first transmission control unit has a portion where only the first thin film is formed on the transparent substrate, and the second transmission control unit 26. The photomask according to configuration 25, wherein the photomask has a portion where only the second thin film is formed on the transparent substrate.
(Configuration 27)
27. The photomask according to configuration 25 or 26, wherein the first thin film is made of a material resistant to the etching agent for the second thin film.

(Configuration 28)
The first thin film is made of a material that is etched by the etching agent for the second thin film, and the second transmission control unit includes an etching stopper film and a portion in which the second thin film is laminated in this order. 26. The photomask according to the structure 25, comprising the photomask.
(Configuration 29)
29. The structure according to any one of configurations 25 to 28, wherein an edge portion of the second transmission control unit adjacent to the first transmission control unit includes a stacked portion of the first thin film and the second thin film. Photo mask.

(Configuration 30)
30. The photomask according to configuration 29, wherein a width M2 of the stacked portion is in a range of 0.5 to 2 [mu] m.
(Configuration 31)
31. The photomask according to any one of configurations 25 to 30, wherein the first thin film is a translucent film and the second thin film is a light shielding film.

(Configuration 32)
A photomask having a transfer pattern including a light transmission portion, a first transmission control portion, and a second transmission control portion on a transparent substrate, wherein the transfer pattern has a predetermined exposure light transmittance. A first thin film pattern comprising one thin film and a second thin film pattern comprising a second thin film, wherein the transparent substrate surface is exposed, and the first transmission control unit is provided on the transparent substrate. The second transmission control unit has a portion where only the second thin film pattern is formed on the transparent substrate, and includes the first transmission. A photomask comprising: a laminated portion between the first thin film pattern and the second thin film pattern sandwiched between a control unit and the second transmission control unit.

(Configuration 33)
33. The photomask according to configuration 32, wherein a width M2 of the stacked portion is in a range of 0.5 to 2 [mu] m.
(Configuration 34)
34. The photomask according to configuration 32 or 33, wherein edges of the first thin film pattern and the second thin film pattern have wet etched cross sections of the first thin film and the second thin film, respectively.

(Configuration 35)
35. The photomask according to any one of configurations 32 to 34, wherein the first thin film is a semi-transparent film that partially transmits exposure light.
(Configuration 36)
The exposure light transmitted through the first transmission control unit has a phase difference φ (degrees) satisfying φ ≦ 90 with respect to a representative wavelength of the exposure light transmitted through the light transmission unit. 34. The photomask according to any one of 34.

(Configuration 37)
The exposure light transmitted through the first transmission control unit has a phase difference φ (degrees) satisfying φ ≦ 90 with respect to the representative wavelength of the exposure light transmitted through the light transmission unit, and a light transmittance Tf ( %) Satisfies 5 ≦ Tf ≦ 60. 35. The photomask according to any one of structures 32 to 34, wherein:
(Configuration 38)
The exposure light transmitted through the first transmission control unit has a phase difference φ (degree) satisfying 150 ≦ φ ≦ 210 with respect to a representative wavelength of the exposure light transmitted through the light transmission unit. The photomask according to any one of 32 to 34.

(Configuration 39)
The exposure light transmitted through the first transmission control unit has a phase difference φ (degree) satisfying 150 ≦ φ ≦ 210 with respect to the representative wavelength of the exposure light transmitted through the light transmitting unit, and light transmittance. 35. The photomask according to any one of structures 32 to 34, wherein Tf (%) satisfies 5 ≦ Tf ≦ 60.
(Configuration 40)
40. The photomask according to any one of configurations 32 to 39, wherein the second thin film is a light shielding film.

(Configuration 41)
40. The photomask according to any one of configurations 32 to 39, wherein the second thin film is a semi-transmissive film that partially transmits exposure light.
(Configuration 42)
The exposure light transmitted through the second transmission control unit has a phase difference φ (degree) satisfying 0 <φ ≦ 90 with respect to a representative wavelength of the exposure light transmitted through the light transmission unit. 40. The photomask according to any one of 32 to 39.

(Configuration 43)
The exposure light transmitted through the second transmission control unit has a phase difference φ (degrees) satisfying 0 <φ ≦ 90 with respect to the representative wavelength of the exposure light transmitted through the light transmission unit, and light transmittance. 40. The photomask according to any one of structures 32 to 39, wherein Tf (%) satisfies 5 ≦ Tf ≦ 80.
(Configuration 44)
The exposure light transmitted through the second transmission control unit has a phase difference φ (degrees) satisfying 150 <φ ≦ 210 with respect to the representative wavelength of the exposure light transmitted through the light transmission unit, and light transmittance. 40. The photomask according to any one of structures 32 to 39, wherein Tf (%) satisfies 5 ≦ Tf ≦ 60.

(Configuration 45)
45. The photomask according to any one of configurations 25 to 44, wherein the transfer pattern is a pattern for manufacturing a display device.
(Configuration 46)
A photomask obtained by the photomask manufacturing method according to any one of Structures 1 to 24 or a photomask according to any one of Structures 25 to 44 is prepared, and the transfer pattern is formed using an exposure apparatus. A method for manufacturing a display device, comprising a step of transferring to a transfer object.

According to the present invention, since only the respective films are etched in the etching steps of the first thin film and the second thin film, the etching time can be set as compared with the case where a plurality of stacked films are continuously etched. Since it is short, variation in pattern dimension (CD) due to side etching can be reduced. In particular, if a single film is etched in all the etching steps, the time required for etching can be calculated in advance based on the film quality and film thickness, so that dimensional variations due to side etching can be minimized. it can. Furthermore, if the configuration of the photomask of the present invention is adopted, the design and management of the optical characteristics (for example, transmittance) of the first transmission control unit and the second transmission control unit are easier and more accurate. Manufacturing a high-spec display device that achieves fine and energy-saving has great significance.
That is, according to the present invention, it is possible to provide a photomask manufacturing method and a photomask capable of manufacturing a finer photomask having higher CD accuracy and optical physical property (transmittance) accuracy. it can.
Furthermore, according to the present invention, it is possible to manufacture a high-spec display device that realizes high definition and energy saving by manufacturing a display device using the photomask.

It is a figure which shows the process of 1st Embodiment of the manufacturing method of the photomask which concerns on this invention. It is a figure which shows the process of 2nd Embodiment of the manufacturing method of the photomask which concerns on this invention. It is a figure which shows the manufacturing process of the conventional photomask disclosed by the prior document. It is a reference drawing which shows the manufacturing process of the conventional photomask for demonstrating the subject of a prior art.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.
[First Embodiment]
The photomask manufacturing method according to the present invention includes a photomask having a transfer pattern including a translucent part, a first transmission control part, and a second transmission control part on a transparent substrate, as in Configuration 1 above. A method of preparing a photomask blank in which a first thin film having a predetermined exposure light transmittance is formed on the transparent substrate; and etching the first thin film to thereby form a first thin film pattern. Forming a second thin film pattern on the transparent substrate on which the first thin film pattern is formed, and forming the second thin film pattern by etching the second thin film; A second patterning step, wherein only the second thin film is etched in the second patterning step.
In the first embodiment described below, the first transmission control unit described above is a semi-transmission unit that partially transmits exposure light, and the second transmission control unit is a light shielding unit. The first thin film is a semi-translucent film, and the second thin film is a light shielding film.

FIG. 1 is a diagram showing steps of a first embodiment of a photomask manufacturing method according to the present invention.
Hereinafter, each process is demonstrated in order.
First, a photomask blank (substrate with a semi-transparent film) 10 in which a semi-transparent film 2 having a predetermined exposure light transmittance is formed on a transparent substrate 1 is prepared (see FIG. 1A).

Here, as the transparent substrate 1, a flat and smooth polished material made of quartz glass or the like is used. As a transparent substrate used for a photomask for manufacturing a display device, it is preferable that a main surface is a quadrangle having a side of 300 mm or more and a thickness of 5 to 13 mm.
A semi-transparent film 2 is formed on one main surface of the transparent substrate 1 by a known film forming means such as sputtering. The material and film thickness of the semi-transparent film 2 can be determined in advance so as to have a desired transmittance with respect to the exposure light used when exposing the photomask.

  As the exposure light, for example, a light source including i-line, h-line, and g-line possessed by a liquid crystal exposure apparatus can be used. Therefore, the standard of transmittance can be for light in these wavelength ranges, and can generally be expressed as a numerical value for the representative wavelength (here, i-line) included in these.

  And it is preferable that the light transmittance Tf of the said semi-transparent film 2 is 5 to 60% (a transparent substrate shall be 100%) with respect to i line | wire. Furthermore, it is preferable that it is 10 to 40%.

  Here, Tf is the light transmittance of the semi-transmissive film 2 to be used as described above. When a fine pattern is formed in the semi-transparent film 2, the light transmittance and the light transmission by the light-shielding part and the translucent part arranged around it are affected by interference, and the effective light transmittance of the semi-transparent part is Although it may be different from that at the time of film formation, here, it means the transmittance inherent to the film, which is not affected by light diffraction and interference by the surrounding pattern. If the semi-transparent film 2 has a laminated structure, the intrinsic transmittance of the laminated film is set.

The semi-transparent film 2 can have a desired phase shift function with respect to the representative wavelength of the exposure light. When considering the formation of a resist pattern having a plurality of remaining film thicknesses on the transfer object as a multi-tone photomask, the phase shift amount (φ) of the semi-transparent film 2 is 0 <φ ≦ 90. It is preferable that the angle is 5 °, and further preferably 5 ≦ φ ≦ 60 °. This is to prevent generation of unnecessary protrusions (in the case of a positive resist) of the resist pattern at positions corresponding to the semi-transparent part and the translucent part of the multi-tone photomask.
Of course, in order to control the shape of the resist pattern formed on the transferred material by the phase shift action, it may be about 150 ≦ φ ≦ 210 degrees, or 60 ≦ φ ≦ 120 degrees.

  The material of the translucent film 2 can be, for example, a film containing Si, Cr, Ta, Zr, etc., and an appropriate material can be selected from these oxides, nitrides, carbides, and the like. . As the Si-containing film, a Si compound (SiON or the like), a transition metal silicide (MoSi or the like), or a compound thereof can be used. Examples of the MoSi compound include MoSi oxide, nitride, oxynitride, oxynitride carbide, and the like.

  When the material of the translucent film 2 is a Cr-containing film, a Cr compound (oxide, nitride, carbide, oxynitride, carbonitride, oxynitride carbide) can be used.

  In the present embodiment, it is desirable that the semi-transparent film 2 has an etching selectivity (different in etching characteristics) with the light shielding film 5 described later. That is, the semi-transparent film 2 is preferably resistant to the etchant of the light-shielding film 5 (specifically, since wet etching is applied in this embodiment, it is an etchant). Here, the term “resistance” means that the etching rate ratio between the semi-transparent film 2 and the light shielding film 5 with respect to the etching solution of the light shielding film 5 is 1/50 or less, preferably 1/100 or less. It is hoped that. From this viewpoint, for example, if a film containing Cr is used for the light-shielding film 5, the semi-transparent film 2 may be Si-based (for example, containing MoSi). Alternatively, the reverse is possible.

  The semi-transparent film 2 can be formed by applying a known method and apparatus such as a sputtering method. The film thickness of the semi-transparent film 2 is determined in advance so as to have a desired transmittance with respect to the exposure light used when exposing the photomask.

  In addition, after forming the semi-transparent film 2, it is preferable to set an appropriate number of measurement points in the surface and measure the light transmittance (absolute value and its in-plane distribution). For example, a spectrophotometer can be used for the measurement. Since the semi-transparent film 2 after film formation may have some film thickness distribution tendency depending on the position of the main surface of the substrate due to the film forming apparatus and film forming conditions, data obtained by measurement is stored. However, it can be used for purposes such as product warranty purposes and reflected in drawing data in subsequent processes. Thus, since the transmittance | permeability management of a semi-transparent film is more simple and accurate, the transmittance | permeability precision can be raised.

Next, the resist film 3 is applied and formed on the surface of the prepared photomask blank 10 to obtain a blank with resist. A predetermined pattern is drawn 4 (first drawing) (see FIG. 1B). If necessary, the surface of the semi-transparent film 2 can be subjected to a surface treatment for improving the adhesion with the resist film 3.
Further, in order to supplement the adhesion between the semi-transparent film 2 and the resist film, a constituent film may be additionally disposed between them.
The material of the constituent film can be selected so that the adhesiveness between the constituent film and the resist film is higher than the adhesiveness between the semi-transparent film and the resist film. That is, by disposing the constituent film, the adhesion between the resist film and the semi-transparent film that are in direct contact with the constituent film can be improved. The material of the additional constituent film is assumed to have higher adhesion to the resist film than adhesion between the semi-transparent film and the resist film. For example, a Cr compound can be used.

  For the formation of the resist film 3, a known one such as a slit coater or a spin coater can be used. Either positive type or negative type resist can be used as appropriate, but here, an example using a positive type will be described.

  A first patterning step is performed. First, a drawing 4 is performed on the coated resist film 3 by using a drawing apparatus with drawing data based on a desired pattern. As the drawing apparatus, an electron beam or a laser can be used, but laser drawing can be used effectively as a photomask for manufacturing a display apparatus.

  Next, the drawn resist film 3 is developed to form a resist pattern 3a (first resist pattern) (see FIG. 1C).

  Next, using the formed resist pattern 3a as an etching mask, the semi-transparent film 2 is wet-etched (first etching) to form the semi-transparent film pattern 2a (see FIG. 1D). Here, since the etching object is only the semi-transparent film 2, the etching end point can be accurately set with reference to the etching rate grasped in advance.

Then, the remaining resist pattern 3a is peeled and removed (see FIG. 1E).
Here, the pattern dimension (CD) of the semi-transparent film pattern 2a is measured as necessary. Since the pattern edge is only a semi-transparent film, measurement can be performed relatively easily.

When an additional constituent film is formed between the semi-transparent film 2 and the resist film 3, the additional film formed by wet etching (preliminary etching) using the resist pattern 3 as an etching mask. The semi-transparent film pattern 2a can be formed by performing wet etching (first etching) on the semi-transparent film 2 using the constituent film pattern as an etching mask.
In this case, it is preferable to remove the additional constituent film pattern before the following second patterning step.

  Next, the light shielding film 5 is formed on the entire surface of the transparent substrate 1 on which the semi-transparent film pattern 2a is formed on the main surface (see FIG. 1 (f)). Also here, an existing film forming apparatus similar to the case of forming the semi-transparent film 2 can be applied.

  The material for the light shielding film 5 can be selected from the same materials as those for the semi-transparent film 2. Alternatively, a single metal such as Cr or Si described above may be used. Furthermore, a reflection reducing layer that reduces (suppresses) light reflection may be provided on the surface portion of the light shielding film.

  As described above, in the present embodiment, the light shielding film 5 is selected so that the etching characteristics are different from those of the material used for the semi-transparent film 2. For example, the light-shielding film 5 has an etching rate ratio with respect to the semi-transparent film 2 with respect to the etching solution of the semi-transparent film 2 is 1/50 or less, preferably 1/100 or less. desirable. Therefore, for example, a Si-containing material can be used for the semi-transparent film 2 and a Cr-containing material can be used for the light-shielding film 5, or vice versa.

  Further, the film thickness of the light shielding film 5 is set in consideration that the light shielding property can be sufficiently exhibited and that an excessive time is not required for the etching described later. Specifically, the optical density OD can be 3 or more, preferably 4 or more, for example, 4 ≦ OD ≦ 6.

Next, a resist film 6 (also positive type here) is applied and formed on the light-shielding film 5, and a predetermined pattern is drawn 7 (second drawing) (see FIG. 1G). The drawing method is the same as in the case of the first drawing.
However, when the in-plane transmittance distribution data obtained by measurement after the semi-transparent film 2 is formed have an unacceptable variation, and this is to be corrected by the pattern of the light shielding film 5. The drawing data for the second drawing can be processed. This is because, for example, in a fine semi-transparent portion adjacent to the light-shielding portion, the transmission intensity of the exposure light that passes through the semi-transparent portion tends to decrease.
Utilizing this principle, for example, for a semi-transparent portion in a region where the transmittance is lower than the design value, the dimension is made larger than the design value to correct in a direction to increase the transmission intensity of the exposure light. Can do.

  Next, the drawn resist film 6 is developed to form a resist pattern 6a (second resist pattern) (see FIG. 1H).

  Next, by using the formed resist pattern 6a as an etching mask, the light shielding film 5 is wet-etched (second etching) to form the light shielding film pattern 5a (see FIG. 1 (i)). Since the etching target here is only the light shielding film 5, it is not difficult to set the etching end point with reference to the etching rate grasped in advance. Further, as described above, in the present embodiment, the semi-transparent film 2 is made of a material that is resistant to the etchant of the light-shielding film 5. Above, only the light shielding film 5 is removed by etching, and the lower semi-transparent film pattern 2a is not affected by etching.

  Then, the remaining resist pattern 6a is peeled off and a photomask 20 (multi-tone photomask) having a transfer pattern including a light transmitting portion, a light shielding portion, and a semi-light transmitting portion is completed (FIG. 1 ( j)).

  Note that the photomask 20 (multi-tone photomask) exemplified here has the following configuration. That is, the transparent substrate surface is exposed from the transparent substrate, and only the semi-transparent film (first thin film) is formed on the transparent substrate in the semi-transparent portion (first transmission control unit). The light shielding part (second transmission control part) has a part in which only the light shielding film (second thin film) is formed on the transparent substrate.

The photomask 20 has an adjacent part of the light shielding part and the semi-translucent part. In the light shielding part, a laminated portion of the semi-light-transmitting film (semi-transmissive film pattern 2a) and the light-shielding film (light-shielding film pattern 5a) is provided in the vicinity of the edge in contact with the semi-light-transmitting part with a predetermined constant width. This is due to the possibility that the light-shielding portion and the semi-transparent portion are not adjacent to each other and are separated when an alignment shift occurs in the above-described two drawing operations (first drawing and second drawing). An alignment margin for absorbing the deviation, which can be formed by processing the drawing data of the first drawing or the second drawing. For example, in the vicinity of the boundary between the light-shielding part and the semi-transparent part, the edge part of the second resist pattern is partially formed (overlapped) with the edge part of the semi-transparent film pattern that has already been formed. The dimension of the second resist pattern can be set. At this time, as processing of drawing data, the width (M1) of the laminated portion is not particularly limited, but is 0.5 μm or more, preferably 0.5 to 2 μm, more preferably 0, for example. .5 to 1 μm.
That is, in the photomask produced by the above manufacturing method, only the semi-transparent film is formed on the transparent substrate and the light-shielding portion is formed only on the transparent substrate except for the laminated portion as the alignment margin. Is formed.

The present invention also provides a photomask.
The photomask 20 obtained by this embodiment has the following characteristics.
That is, a photomask provided with a transfer pattern including a translucent portion, a light-shielding portion, and a semi-translucent portion on a transparent substrate, wherein the translucent portion is formed by exposing the transparent substrate surface, The semi-transparent part is formed by forming the semi-transparent film without forming the light-shielding film on the transparent substrate, and the light-shielding part has at least the light-shielding film formed on the transparent substrate. In the photomask, the boundary between the semi-transparent part and the light-shielding part is not formed with the cross-section to be etched of the semi-translucent film but is formed with the cross-section to be etched of the light-shielding film. is there.
That is, as apparent from FIG. 1 (j), the edges of the semi-transparent film pattern and the light-shielding film pattern have wet etched cross sections of the semi-transparent film and the light-shielding film, respectively. The edge position does not match the edge position of the light shielding film pattern. In addition, the to-be-etched cross section here is a cross section by wet etching in this embodiment.
As described above, the positions of the cross sections to be etched of the semi-transparent film and the light shielding film do not coincide with each other because of the alignment margin described above.

The materials of the semi-transparent film and the light-shielding film in the photomask are as described above. In the photomask of this embodiment, the semi-transparent film is an etching agent for the light-shielding film. In contrast, it is made of a material having resistance.
Further, an edge portion adjacent to the semi-transparent portion of the light shielding portion includes a laminated portion of the semi-transparent film and the light shielding film, and a width M (see FIG. 1 (j)) of the laminated portion is, for example, 0. A range of 5 to 2 μm is preferable.
In the photomask of this embodiment, the transfer pattern is, for example, a pattern for manufacturing a display device, and is particularly useful for manufacturing a display device.

As described above, according to the present embodiment, only the respective films are etched in the respective etching steps of the semi-transparent film and the light shielding film, and therefore, compared to the case where a plurality of stacked films are continuously etched. In addition, since the setting of the etching time is short, variation in the pattern dimension (CD) due to side etching can be reduced. In particular, if a single film is etched in all the etching steps, the time required for etching can be calculated in advance based on the film quality and film thickness, so that dimensional variations due to side etching can be minimized. it can. Furthermore, if the configuration of the photomask of this embodiment is adopted, the transmittance management of the semi-transparent film is simpler and more accurate, so that it is possible to manufacture a high-spec display device that realizes high definition and energy saving. Has great significance.
That is, according to the present embodiment, it is possible to provide a photomask manufacturing method and a photomask capable of manufacturing a multi-tone photomask that is finer and has higher CD accuracy and transmittance accuracy. .

In the above embodiment, the first transmission control unit is a semi-transmission unit that partially transmits exposure light, the second transmission control unit is a light-shielding unit, and the first thin film is a semi-transmission film and a second thin film. As described above, the light-shielding film is taken as an example, but the manufacturing method of the present invention can provide excellent effects even when other thin films are applied. For example, the first thin film and the second thin film may each be a semi-transparent film having a predetermined exposure light transmittance. In this case, the first thin film and the second thin film can each be a film containing Si, Cr, Ta, Zr, etc., exemplified as the above-described semi-transparent film material, and these oxides and nitrides An appropriate one can be selected from carbides and the like.
In the case where the first thin film and the second thin film are semi-transparent films each having a predetermined exposure light transmittance, in the case where resistance between the two is given between the two, for example, one is Cr-based and the other is Can be Si-based or transition metal silicide-based.

In the photomask of the present invention, as an application method of the first thin film and the second thin film, for example, more specifically,
a. The exposure light transmitted through the first transmission control unit having a portion where only the first thin film is formed on the transparent substrate is relative to the representative wavelength of the exposure light transmitted through the light transmitting unit where the transparent substrate surface is exposed. When the phase difference φ (degree) satisfies φ ≦ 90,
b. The exposure light transmitted through the first transmission control unit has a phase difference φ (degrees) satisfying φ ≦ 90 with respect to the representative wavelength of the exposure light transmitted through the light transmission unit, and a light transmittance Tf ( %) Satisfies 5 ≦ Tf ≦ 60,
c. When the exposure light transmitted through the first transmission control unit has a phase difference φ (degrees) satisfying 150 ≦ φ ≦ 210 with respect to the representative wavelength of the exposure light transmitted through the light transmitting unit,
d. The exposure light transmitted through the first transmission control unit has a phase difference φ (degree) satisfying 150 ≦ φ ≦ 210 with respect to the representative wavelength of the exposure light transmitted through the light transmitting unit, and light transmittance. When Tf (%) satisfies 5 ≦ Tf ≦ 60,
e. The exposure light transmitted through the second transmission control unit having a portion where only the second thin film is formed on the transparent substrate has a phase difference φ (degrees) with respect to the representative wavelength of the exposure light transmitted through the light transmission unit. ) Satisfies 0 <φ ≦ 90,
f. The exposure light transmitted through the second transmission control unit has a phase difference φ (degrees) satisfying 0 <φ ≦ 90 with respect to the representative wavelength of the exposure light transmitted through the light transmission unit, and light transmittance. When Tf (%) satisfies 5 ≦ Tf ≦ 80,
g. The exposure light transmitted through the second transmission control unit has a phase difference φ (degrees) satisfying 150 <φ ≦ 210 with respect to the representative wavelength of the exposure light transmitted through the light transmission unit, and light transmittance. When Tf (%) satisfies 5 ≦ Tf ≦ 60,
Is a useful example. In any case, the CD accuracy is high and controllable, the effects of the present invention can be obtained, and the optical characteristics to be assigned to the first transmission control unit and the second transmission control unit can be designed independently. Thus, a high-quality photomask having a desired design value can be manufactured.

For example, as an example of the photomask described in the first embodiment, the a. Or b. When a light shielding film is applied to the second thin film, a multi-tone photomask can be obtained as the photomask of the present invention. As described above, such a multi-tone photomask has a function equivalent to a plurality of photomasks, and increases the manufacturing efficiency of the display device or forms a three-dimensional structure with a step by transferring. There is an advantage that it is used as a photomask.
Further, the c. Or d. When is applied, the photomask of the present invention can be configured as a phase shift mask. In this case, a light shielding film may be applied to the second thin film, or e. Or f. The semi-transparent film described in (1) may be applied. The phase shift mask has a function of improving contrast and DOF (Depth of Focus) by using interference of light generated at a boundary between a semi-transparent portion where the phase of transmitted light is inverted and a non-inverted transparent portion.
In particular, the c. Or d. Is applied to the second thin film. Or f. When is applied, a photomask having both functions of a multi-tone photomask and a phase shift mask can be configured.

In addition, when both the first transmission control unit and the second transmission control unit are semi-translucent units, the width of the stacked portion where the first thin film and the second thin film are stacked is formed near the boundary. Since it is sufficiently small, it does not substantially impede the optical action of the photomask. In this case, the width of the laminated portion is more preferably 1 μm or less, and further 0.75 μm or less. More preferably, it is 0.25 to 0.75 μm.
Further, the width M1 of the stacked portion on the drawing data can be set in the same range.
On the other hand, it is preferable that the dimensions of the first transmittance control unit and the second transmission control unit (or the light shielding unit) exceed 2 μm, preferably exceed 3 μm, even in the smallest part.

[Second Embodiment]
FIG. 2 is a diagram showing the steps of the second embodiment of the photomask manufacturing method according to the present invention.
Hereinafter, each process is demonstrated in order.
First, a photomask blank 10 in which a semi-transparent film 2 having a predetermined exposure light transmittance is formed on a transparent substrate 1 is prepared (see FIG. 2A).

The photomask blank 10 is the same as the photomask blank prepared in the first embodiment. Therefore, the range of the light transmittance Tf of the semi-transparent film 2 can be the same as that in the first embodiment. Further, the material of the semi-translucent film 2 may be appropriately selected from those exemplified in the first embodiment.
However, in this embodiment, since an etching stopper film is provided between the semi-transparent film and the light-shielding film as described later, the etching characteristics are different between the semi-transparent film 2 and the light-shielding film 5 described later. You don't have to. Therefore, for example, there is no problem in using a Cr-based material for the material of the semi-transparent film 2 and the light-shielding film 5 being a Cr-based material.

  Further, after the semi-translucent film 2 is formed, it is preferable to set an appropriate number of measurement points in the plane and measure the light transmittance in the same manner as in the first embodiment. Since it is formed as a single film on the substrate, it can be measured easily and accurately.

  Next, the resist film 3 is applied and formed on the photomask blank 10, and a predetermined pattern is drawn 4 (first drawing) (see FIG. 2B). If necessary, the surface of the semi-transparent film 2 can be subjected to a surface treatment that improves the adhesion with the resist film.

The resist film 3 can be formed by applying a known material such as a slit coater or a spin coater as described above. Either positive type or negative type resist can be used as appropriate, but in this embodiment, an example using a positive type will be described.
The formed resist film 3 is drawn with drawing data based on a desired pattern using a drawing apparatus. As in the first embodiment, a laser is applied to the drawing apparatus.

  Then, the drawn resist film 3 is developed to form a resist pattern 3a (first resist pattern) (see FIG. 2C).

  Next, by using the formed resist pattern 3a as an etching mask, the semi-transparent film 2 is wet-etched (first etching) to form the semi-transparent film pattern 2a (see FIG. 2D). . Also here, since the etching target is only the semi-transparent film 2, the etching end point can be accurately set with reference to the etching rate grasped in advance.

The remaining resist pattern 3a is peeled and removed (see FIG. 2E).
Here, the pattern dimension (CD) of the semi-transparent film pattern 2a is measured as necessary. Since the pattern edge is only a semi-transparent film, measurement can be performed relatively easily.

In this embodiment, next, an etching stopper film 8 is formed on the entire surface of the transparent substrate 1 on which the semi-transparent film pattern 2a is formed on the main surface (see FIG. 2F).
The etching stopper film 8 is made of a material having resistance to an etching agent for the light shielding film 5 described later. For example, the etching stopper film 8 has an etching rate ratio with respect to the light shielding film 5 with respect to the etching solution of the light shielding film 5 of 1/50 or less, preferably 1/100 or less.

  Therefore, for example, when a Cr-containing material is used for the light shielding film 5, a Si-containing material can be used for the etching stopper film 8, or vice versa. In consideration of these, the material of the etching stopper film 8 can be selected from the same materials as those described as the materials of the semi-transparent film and the light shielding film in the first embodiment.

  Next, a light shielding film 5 is further formed on the etching stopper film 8, that is, on the main surface of the transparent substrate 1 on which the semi-translucent film pattern 2a and the etching stopper film 8 are formed (FIG. 2G )reference).

The etching stopper film 8 and the light shielding film 5 can be formed by applying the same film forming apparatus as described above.
Further, the material of the light shielding film 5 may be appropriately selected from those exemplified in the first embodiment. However, as mentioned above, in the present embodiment, the material of the light shielding film 5 is the above half. There is no need for mutual etching selectivity with the translucent film 2.

Next, a resist film 6 (also positive type here) is applied and formed on the light shielding film 5, and a predetermined pattern 7 is drawn (second drawing) (see FIG. 2H). The drawing method is the same as in the case of the first drawing.
As described above, the in-plane transmittance distribution data obtained after the measurement of the semi-transparent film 2 has an unacceptable variation, and this is to be corrected by the pattern of the light shielding film 5. In this case, the drawing data for the second drawing can be processed.

  Next, the drawn resist film 6 is developed to form a resist pattern 6a (second resist pattern) (see FIG. 2I).

  Next, by using the formed resist pattern 6a as an etching mask, the light shielding film 5 is wet-etched (second etching) to form the light shielding film pattern 5a (see FIG. 2J). Since the etching target here is only the light shielding film 5, it is not difficult to set the etching end point with reference to the etching rate grasped in advance. Further, as described above, in the present embodiment, the etching stopper film 8 is made of a material resistant to the etchant of the light shielding film 5, so that only the light shielding film 5 is etched away in the second etching. The

  Then, the remaining resist pattern 6a is peeled and removed to complete a photomask 30 (multi-tone photomask) having a transfer pattern including a light transmitting portion, a light shielding portion, and a semi-light transmitting portion (FIG. 2 ( k)).

  Thereafter, the etching stopper film 8 exposed on the surface of the photomask 30 is removed as necessary. When the etching stopper film 8 is removed, it is assumed that there is an etching selectivity between the semi-transparent film 2 and the etching stopper film 8 in advance. That is, for example, both the translucent film 2 and the light shielding film 5 can be Cr-containing films, and the etching stopper film 8 can be a Si-containing film, or vice versa. Note that the etching stopper film 8 may be left unremoved when the light transmittance at the semi-translucent portion or the translucent portion of the photomask 30 is not particularly affected.

  Note that the photomask 30 (multi-tone photomask) exemplified in this embodiment also has an adjacent portion of the light shielding portion and the semi-transparent portion. In the light shielding part, a laminated portion of the semi-light-transmitting film (semi-transmissive film pattern 2a) and the light-shielding film (light-shielding film pattern 5a) is provided in the vicinity of the edge in contact with the semi-light-transmitting part with a predetermined constant width. This is due to the possibility that the light-shielding portion and the semi-transparent portion are not adjacent to each other and are separated when an alignment shift occurs in the above-described two drawing operations (first drawing and second drawing). An alignment margin for absorbing the deviation, which can be formed by processing the drawing data of the first drawing or the second drawing. For example, the width M of the laminated portion (see FIG. 2 (k)) is not particularly limited, but may be 0.5 to 2 μm, preferably 0.5 to 1 μm, for example. This is also the same as in the first embodiment.

Further, the photomask 30 obtained according to the present embodiment also has the following features as in the first embodiment.
That is, a photomask provided with a transfer pattern including a translucent portion, a light-shielding portion, and a semi-translucent portion on a transparent substrate, wherein the translucent portion is formed by exposing the transparent substrate surface, The semi-transparent part is formed by forming the semi-transparent film without forming the light-shielding film on the transparent substrate, and the light-shielding part has at least the light-shielding film formed on the transparent substrate. In the photomask, the boundary between the semi-transparent part and the light-shielding part is not formed with the cross-section to be etched of the semi-translucent film but is formed with the cross-section to be etched of the light-shielding film. is there.

The materials of the semi-transparent film and the light-shielding film in the photomask are as described above. In the photomask of this embodiment, etching is performed between the semi-transparent film and the light-shielding film. Selectivity is not necessary.
Further, the edge portion adjacent to the semi-transparent portion of the light-shielding portion has a laminated portion of the semi-transparent film and the light-shielding film, and this laminated portion may have a width in the range of 0.5 to 2 μm, for example. As described above.
In the photomask of this embodiment, the transfer pattern is, for example, a pattern for manufacturing a display device, and is particularly useful for manufacturing a display device.

As described above, also in the present embodiment, only the respective films are etched in the respective etching steps of the semi-transparent film and the light-shielding film, and therefore, compared with the case where a plurality of stacked films are continuously etched. Since the setting of the etching time is short, variation in pattern dimension (CD) due to side etching can be reduced. In particular, if a single film is etched in all the etching steps, the time required for etching can be calculated in advance based on the film quality and film thickness, so that dimensional variations due to side etching can be minimized. it can. Furthermore, if the configuration of the photomask of this embodiment is adopted, the transmittance management of the semi-transparent film is simpler and more accurate, so that it is possible to manufacture a high-spec display device that realizes high definition and energy saving. Has great significance.
That is, according to the present embodiment, it is possible to provide a photomask manufacturing method and a photomask capable of manufacturing a multi-tone photomask that is finer and has higher CD accuracy and transmittance accuracy. .

  Also in the present embodiment, the first transmission control unit includes a semi-transmission unit that partially transmits exposure light, the second transmission control unit as a light-blocking unit, a semi-transmission film as the first thin film, and a second film. Although the light-shielding film has been described as an example of the thin film, the present invention is not limited to this, and an excellent effect can be obtained when another thin film is applied. For example, the first thin film and the second thin film may each be a semi-transparent film having a predetermined exposure light transmittance.

Also in the photomask of this embodiment, as an application method of the first thin film and the second thin film, for example, more specifically,
a. The exposure light transmitted through the first transmission control unit having a portion where only the first thin film is formed on the transparent substrate is relative to the representative wavelength of the exposure light transmitted through the light transmitting unit where the transparent substrate surface is exposed. When the phase difference φ (degree) satisfies φ ≦ 90,
b. The exposure light transmitted through the first transmission control unit has a phase difference φ (degrees) satisfying φ ≦ 90 with respect to the representative wavelength of the exposure light transmitted through the light transmission unit, and a light transmittance Tf ( %) Satisfies 5 ≦ Tf ≦ 60,
c. When the exposure light transmitted through the first transmission control unit has a phase difference φ (degrees) satisfying 150 ≦ φ ≦ 210 with respect to the representative wavelength of the exposure light transmitted through the light transmitting unit,
d. The exposure light transmitted through the first transmission control unit has a phase difference φ (degree) satisfying 150 ≦ φ ≦ 210 with respect to the representative wavelength of the exposure light transmitted through the light transmitting unit, and light transmittance. When Tf (%) satisfies 5 ≦ Tf ≦ 60,
e. The exposure light transmitted through the second transmission control unit having a portion where only the second thin film is formed on the transparent substrate has a phase difference φ (degrees) with respect to the representative wavelength of the exposure light transmitted through the light transmission unit. ) Satisfies 0 <φ ≦ 90,
f. The exposure light transmitted through the second transmission control unit has a phase difference φ (degrees) satisfying 0 <φ ≦ 90 with respect to the representative wavelength of the exposure light transmitted through the light transmission unit, and light transmittance. When Tf (%) satisfies 5 ≦ Tf ≦ 80,
g. The exposure light transmitted through the second transmission control unit has a phase difference φ (degrees) satisfying 150 <φ ≦ 210 with respect to the representative wavelength of the exposure light transmitted through the light transmission unit, and light transmittance. When Tf (%) satisfies 5 ≦ Tf ≦ 60,
Is a useful example. In any case, the CD accuracy is high and controllable, the effects of the present invention can be obtained, and the optical characteristics to be assigned to the first transmission control unit and the second transmission control unit can be designed independently. Thus, a high-quality photomask having a desired design value can be manufactured.
The photomask of the present invention according to the second embodiment also has the above described a. ~ G. Such a configuration can be selected as appropriate to suit the application.

Heretofore, the first embodiment and the second embodiment of the present invention have been described.
In the above embodiment, the other constituent films are above, below, or in the middle of any of the semi-transparent film 2, the light shielding film 5, and the etching stopper film 8 as long as the effects of the present invention are not hindered. May be present.

  The present invention also provides a method for manufacturing a display device, including a step of preparing a photomask according to the above-described embodiment and transferring a transfer pattern onto a transfer target using an exposure apparatus, for example. Is. According to the present invention, by manufacturing a display device using the photomask, a high-spec display device that realizes high definition and energy saving can be manufactured.

  That is, there are no restrictions on the use of the photomask of the present invention. For example, as a device for producing a panel substrate of a display device (for example, a liquid crystal display or an organic EL display), transfer patterns used for various layers can be provided.

  For example, those having a transfer pattern for manufacturing a TFT (Thin Film Transistor) are exemplified. In a bottom gate type TFT using amorphous Si or an oxide semiconductor, it is advantageously applied as a photomask used in a process of forming a semiconductor layer and a source / drain (Drain) layer by one exposure.

  Alternatively, the photomask of the present invention is also advantageously applied when a liquid crystal spacer is manufactured using a photosensitive insulating layer. It can be used for the step of forming a step structure on the photosensitive insulating film by one exposure, and a spacer for forming a cell gap and a spacer having a slightly lower height to prevent destruction at the time of applying pressure are used once. It can be formed efficiently by this exposure.

  As an exposure apparatus for use in exposure of the photomask of the present invention, for example, the numerical aperture (NA) of the optical system is 0.08 to 0.15, and the coherence factor (σ) is 0.5 to 0.9. An equal magnification projection exposure method can be used. Alternatively, a proximity exposure method may be applied. Of course, you may apply to the exposure apparatus of reduction exposure or expansion exposure.

DESCRIPTION OF SYMBOLS 1 Transparent substrate 2 Semi-transparent film 3, 6 Resist film 4, 7 Drawing 5 Light shielding film 8 Etching stopper film 10 Photomask blank (substrate with semi-transparent film)
20, 30 Photomask

Claims (46)

A method for producing a photomask comprising a transfer pattern including a translucent part, a first transmission control part, and a second transmission control part on a transparent substrate,
Preparing a photomask blank in which a first thin film having a predetermined exposure light transmittance is formed on the transparent substrate;
A first patterning step of forming a first thin film pattern by etching the first thin film;
Forming a second thin film on the transparent substrate on which the first thin film pattern is formed, and forming a second thin film pattern by etching the second thin film, and a second patterning step,
In the second patterning step, only the second thin film is etched, and the photomask manufacturing method is characterized. The transparent portion is formed by exposing the transparent substrate surface,
The first transmission control unit has a portion where only the first thin film is formed on the transparent substrate,
2. The photomask manufacturing method according to claim 1, wherein the second transmission control unit includes a portion where only the second thin film is formed on the transparent substrate.   3. The method of manufacturing a photomask according to claim 1, wherein the first thin film is made of a material having resistance to an etchant for the second thin film.   3. The method of manufacturing a photomask according to claim 1, wherein the first thin film is made of a material that is etched by an etchant for the second thin film.   5. The method according to claim 4, further comprising: forming an etching stopper film on the transparent substrate on which the first thin film pattern is formed after the first patterning process and before forming the second thin film. A method for producing a photomask according to 1.   6. The photomask according to claim 5, further comprising a step of removing the etching stopper film of the light transmitting portion or the light transmitting portion and the first transmission control portion after the second patterning step. Manufacturing method.   The photomask manufacturing method according to claim 1, wherein the first thin film is a semi-transparent film that partially transmits exposure light.   The exposure light transmitted through the first transmission control unit has a phase difference φ (degree) satisfying φ ≦ 90 with respect to a representative wavelength of the exposure light transmitted through the light transmission unit. 7. A method for producing a photomask according to any one of items 1 to 6.   The exposure light transmitted through the first transmission control unit has a phase difference φ (degrees) satisfying φ ≦ 90 with respect to the representative wavelength of the exposure light transmitted through the light transmission unit, and the first transmission control. The photomask manufacturing method according to claim 1, wherein the light transmittance Tf (%) of the portion satisfies 5 ≦ Tf ≦ 60.   The exposure light transmitted through the first transmission control unit has a phase difference φ (degree) satisfying 150 ≦ φ ≦ 210 with respect to a representative wavelength of the exposure light transmitted through the light transmitting unit. Item 7. A method for producing a photomask according to any one of Items 1 to 6.   The exposure light transmitted through the first transmission control unit has a phase difference φ (degree) satisfying 150 ≦ φ ≦ 210 with respect to the representative wavelength of the exposure light transmitted through the light transmitting unit, and light transmittance. The photomask manufacturing method according to claim 1, wherein Tf (%) satisfies 5 ≦ Tf ≦ 60.   The method for manufacturing a photomask according to claim 1, wherein the second thin film is a semi-transparent film that partially transmits exposure light.   The exposure light transmitted through the second transmission control unit has a phase difference φ (degree) satisfying 0 <φ ≦ 90 with respect to a representative wavelength of the exposure light transmitted through the light transmission unit. Item 12. A method for producing a photomask according to any one of Items 1 to 11.   The exposure light transmitted through the second transmission control unit has a phase difference φ (degrees) satisfying 0 <φ ≦ 90 with respect to the representative wavelength of the exposure light transmitted through the light transmission unit, and light transmittance. 12. The method of manufacturing a photomask according to claim 1, wherein Tf (%) satisfies 5 ≦ Tf ≦ 80.   The exposure light transmitted through the second transmission control unit has a phase difference φ (degrees) satisfying 150 <φ ≦ 210 with respect to the representative wavelength of the exposure light transmitted through the light transmission unit, and light transmittance. 12. The method of manufacturing a photomask according to claim 1, wherein Tf (%) satisfies 5 ≦ Tf ≦ 60.   The method of manufacturing a photomask according to claim 1, wherein the second thin film is a light shielding film.   The photomask manufacturing method according to claim 16, wherein a reflection reducing layer for reducing light reflection is provided on a surface portion of the second thin film.   The photomask blank manufacturing method according to claim 1, wherein the photomask blank has an additional component film and a resist film on the first thin film.   The method of manufacturing a photomask according to claim 18, wherein the adhesion between the additional component film and the resist film is higher than the adhesion between the first thin film and the resist film. Before the first patterning step, a preliminary patterning step of etching the additional constituent film to form an additional constituent film pattern,
20. The method of manufacturing a photomask according to claim 18, wherein in the first patterning step, the first thin film is etched using the additional constituent film pattern as a mask.   21. The method of manufacturing a photomask according to claim 20, wherein the additional film pattern is removed after the first patterning process and before the second patterning process. On the transparent substrate, a transfer pattern including a translucent part, a first transmission control part, and a second transmission control part, including an adjacent part adjacent to the first transmission control part and the second transmission control part is provided. A method of manufacturing a photomask,
Preparing a photomask blank in which a first thin film having a predetermined exposure light transmittance is formed on the transparent substrate;
Forming a first resist pattern in a region to be the first transmission control unit and etching the first thin film to form a first thin film pattern;
A film forming step of forming a second thin film on the transparent substrate on which the first thin film pattern is formed;
A second patterning step of forming a second thin film pattern by forming a second resist pattern in a region to be the second transmission control unit and etching the second thin film;
In the second patterning step, in the adjacent portion, the second resist pattern is stacked with the first thin film pattern, and a stacked portion is formed.
A method of manufacturing a photomask, wherein only the second thin film is etched using the second resist pattern. The transparent portion is formed by exposing the transparent substrate surface,
The first transmission control unit includes a portion where only the first thin film is formed on the transparent substrate,
23. The photomask manufacturing method according to claim 22, wherein the second transmission control unit includes a portion where only the second thin film is formed on the transparent substrate.   The method for manufacturing a photomask according to claim 22 or 23, wherein the width M1 of the laminated portion is in the range of 0.5 to 2 µm. A photomask provided with a transfer pattern including a translucent part, a first transmission control part, and a second transmission control part on a transparent substrate,
The transfer pattern includes a first thin film having a predetermined exposure light transmittance and a second thin film,
The transparent portion is formed by exposing the transparent substrate surface,
The first transmission control unit is formed by forming the first thin film on the transparent substrate without forming the second thin film.
The second transmission control unit includes at least the second thin film formed on the transparent substrate,
The boundary between the first transmission control unit and the second transmission control unit is not a cross section to be etched of the first thin film but a cross section to be etched of the second thin film. mask. The transparent portion is formed by exposing the transparent substrate surface,
The first transmission control unit has a portion where only the first thin film is formed on the transparent substrate,
26. The photomask according to claim 25, wherein the second transmission control unit has a portion where only the second thin film is formed on the transparent substrate.   27. The photomask according to claim 25 or 26, wherein the first thin film is made of a material resistant to the etching agent for the second thin film.   The first thin film is made of a material that is etched by the etching agent for the second thin film, and the second transmission control unit includes an etching stopper film and a portion in which the second thin film is laminated in this order. The photomask according to claim 25, further comprising:   The edge portion adjacent to the first transmission control unit of the second transmission control unit includes a stacked portion of the first thin film and the second thin film. The photomask described.   30. The photomask according to claim 29, wherein a width M2 of the stacked portion is in a range of 0.5 to 2 [mu] m.   31. The photomask according to claim 25, wherein the first thin film is a translucent film and the second thin film is a light shielding film. A photomask provided with a transfer pattern including a translucent part, a first transmission control part, and a second transmission control part on a transparent substrate,
The transfer pattern includes a first thin film pattern made of a first thin film having a predetermined exposure light transmittance and a second thin film pattern made of a second thin film,
The transparent portion is formed by exposing the transparent substrate surface,
The first transmission control unit has a portion where only the first thin film pattern is formed on the transparent substrate,
The second transmission control unit has a portion where only the second thin film pattern is formed on the transparent substrate,
A photomask comprising: a stacked portion where the first thin film pattern and the second thin film pattern are stacked, sandwiched between the first transmission control unit and the second transmission control unit.   The photomask according to claim 32, wherein a width M2 of the stacked portion is in a range of 0.5 to 2 µm.   34. The photomask according to claim 32 or 33, wherein edges of the first thin film pattern and the second thin film pattern have wet etched cross sections of the first thin film and the second thin film, respectively.   The photomask according to any one of claims 32 to 34, wherein the first thin film is a semi-transparent film that partially transmits exposure light.   The exposure light transmitted through the first transmission control unit has a phase difference φ (degree) satisfying φ ≦ 90 with respect to a representative wavelength of the exposure light transmitted through the light transmission unit. 35. The photomask according to any one of thru 34.   The exposure light transmitted through the first transmission control unit has a phase difference φ (degrees) satisfying φ ≦ 90 with respect to the representative wavelength of the exposure light transmitted through the light transmission unit, and a light transmittance Tf ( %) Satisfies 5 ≦ Tf ≦ 60. 35. The photomask according to claim 32, wherein: 5 ≦ Tf ≦ 60.   The exposure light transmitted through the first transmission control unit has a phase difference φ (degree) satisfying 150 ≦ φ ≦ 210 with respect to a representative wavelength of the exposure light transmitted through the light transmitting unit. Item 35. The photomask according to any one of Items 32 to 34.   The exposure light transmitted through the first transmission control unit has a phase difference φ (degree) satisfying 150 ≦ φ ≦ 210 with respect to the representative wavelength of the exposure light transmitted through the light transmitting unit, and light transmittance. 35. The photomask according to claim 32, wherein Tf (%) satisfies 5 ≦ Tf ≦ 60.   40. The photomask according to claim 32, wherein the second thin film is a light shielding film.   40. The photomask according to claim 32, wherein the second thin film is a semi-transmissive film that partially transmits exposure light.   The exposure light transmitted through the second transmission control unit has a phase difference φ (degree) satisfying 0 <φ ≦ 90 with respect to a representative wavelength of the exposure light transmitted through the light transmission unit. Item 42. The photomask according to any one of Items 32 to 39.   The exposure light transmitted through the second transmission control unit has a phase difference φ (degrees) satisfying 0 <φ ≦ 90 with respect to the representative wavelength of the exposure light transmitted through the light transmission unit, and light transmittance. 40. The photomask according to claim 32, wherein Tf (%) satisfies 5 ≦ Tf ≦ 80.   The exposure light transmitted through the second transmission control unit has a phase difference φ (degrees) satisfying 150 <φ ≦ 210 with respect to the representative wavelength of the exposure light transmitted through the light transmission unit, and light transmittance. 40. The photomask according to claim 32, wherein Tf (%) satisfies 5 ≦ Tf ≦ 60.   45. The photomask according to claim 25, wherein the transfer pattern is a pattern for manufacturing a display device.   A photomask obtained by the photomask manufacturing method according to any one of claims 1 to 24 or a photomask according to any one of claims 25 to 44 is prepared, and the transfer mask is used by using an exposure apparatus. A method for manufacturing a display device, comprising a step of transferring a pattern to a transfer target.

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