KR20130102522A - Method for transferring pattern, and method for manufacturing flat panel display - Google Patents

Abstract

PURPOSE: A pattern transcription method, a manufacturing method of a flat panel display, and a manufacturing method of the photomask are provided to use a photomask including a minute or high precision transcription pattern. CONSTITUTION: A pattern transcription method comprises a step of preparing a photomask with a transcription pattern, and a step of transcribing the transcription pattern on a transcribing object using an exposure device. The transcription pattern includes a light-transmitting part obtained by patterning upper and lower layers formed on a transparent substrate (10), a light shielding part, and a semi light-transmitting part. The light-transmitting part is formed by exposing the transparent substrate. The light shielding part is formed by laminating the upper layer (30) on the lower layer (20). The semi light-transmitting part is formed by forming the lower layer on the transparent substrate. [Reference numerals] (A) Painting; (AA) Side etching; (B) Developing; (C) Upper layer preliminary etching; (D) Lower layer patterning; (E) Upper layer patterning; (F) Register pattern removing

Description

Pattern transfer method and manufacturing method of flat panel display {METHOD FOR TRANSFERRING PATTERN, AND METHOD FOR MANUFACTURING FLAT PANEL DISPLAY}

This invention relates to the manufacturing method of the photomask used for the pattern transfer to a to-be-transferred body, the photomask, the pattern transfer method using the same, and the manufacturing method of a flat panel display.

In manufacture of a flat panel display represented by a liquid crystal display device and an organic electroluminescent (EL) display, it is necessary to aim at the improvement of image quality by forming a finer pattern. Patent Document 1 describes a phase shift mask in which a light shielding film is patterned to form a phase shift layer having a film thickness of 180 ° with respect to an i-line so as to cover the light shielding film. Pattern formation is supposed to be possible.

Japanese Patent Application Laid-Open No. 2011-13283

In recent years, miniaturization of a wiring pattern of a flat panel display is desired. Such miniaturization has advantages in terms of energy saving as well as enhancement of image quality such as improvement of brightness of a flat panel display and improvement of reaction speed. In connection with this, the photomask used for manufacture of a flat panel display also raises the requirement of the precision of a critical dimension (CD). However, it is not easy to refine the wiring pattern of a flat panel display by simply miniaturizing the transfer pattern of the photomask.

In view of the above circumstances, an object of the present invention is to propose a photomask having a fine and highly accurate transfer pattern, a manufacturing method thereof, a pattern transfer method using such a photomask, and a manufacturing method of a flat panel display. It is.

According to the first aspect of the present invention,

A method of manufacturing a photomask having a transfer pattern in which a lower layer film and an upper layer film formed on a transparent substrate, respectively, are patterned,

Preparing a photomask blank formed by laminating a lower layer film and an upper layer film on a transparent substrate,

An upper layer film pre-etching step of etching the upper layer film using a resist pattern formed on the upper layer film as a mask;

An underlayer film patterning step of etching the underlayer film using at least the etched upper layer film as a mask to form an underlayer film pattern;

There is provided a method of manufacturing a photomask having an upper layer film patterning step of side etching the upper layer film using at least the resist pattern as a mask to form an upper layer pattern.

According to a second aspect of the present invention,

The underlayer film is a semi-transmissive film that partially transmits the exposure light used when transferring the transfer pattern to the transfer target, and the upper layer film is a light shielding film that substantially shields the exposure light. A method is provided.

According to the third aspect of the present invention,

The transfer pattern includes a light transmissive portion on which the transparent substrate is exposed, a light shielding portion formed by laminating a lower layer film and an upper layer film on the transparent substrate, a lower layer film formed on the transparent substrate, and a translucent portion having no upper layer film. The manufacturing method of the photomask as described in a 1st or 2nd aspect is provided.

According to the fourth aspect of the present invention,

The said transfer pattern is provided with the manufacturing method of the photomask in any one of the 1st-3rd aspect which has the said translucent part of 0.1 micrometer-1.0 micrometer of line widths formed adjacent to the edge of the said light shielding part.

According to the fifth aspect of the present invention,

The underlayer film has a transmittance of 2 to 90% with respect to the representative wavelength contained in the exposure light, and the photomask according to any one of the first to fourth aspects, wherein the amount of phase shift with respect to the representative wavelength is approximately 180 °. A method for producing is provided.

According to the sixth aspect of the present invention,

The underlayer film has a transmittance of 2 to 60% with respect to the representative wavelength contained in the exposure light, and the aspect of any one of the first to fourth aspects in which the amount of phase shift with respect to the representative wavelength exceeds 0 ° and is 90 ° or less. The manufacturing method of the photomask described in is provided.

According to the seventh aspect of the present invention,

The manufacturing method of the photomask as described in any one of the 1st-5th aspect which performs wet etching using the same etchant in the said upper layer film patterning process and the said upper layer film preliminary etching process is provided.

According to the eighth aspect of the present invention,

A photomask having a transfer pattern comprising a light transmitting portion, a light blocking portion, and a semi-transparent portion formed by patterning a lower layer film and an upper layer film on a transparent substrate, respectively.

The light transmitting portion is formed by exposing the transparent substrate,

The light shielding portion is formed by laminating an upper layer film on the lower layer film on the transparent substrate,

The semi-transmissive portion is formed by forming the underlayer film on the transparent substrate, and further provided with a photomask having a portion having a predetermined line width of 1.0 μm or less formed adjacent to an edge of the light blocking portion.

According to the ninth aspect of the present invention,

A photomask having a transfer pattern comprising a light transmitting portion, a light blocking portion, and a semi-transparent portion formed by patterning a lower layer film and an upper layer film on a transparent substrate, respectively.

The light transmitting portion is formed by exposing the transparent substrate,

The light shielding portion is formed by laminating an upper layer film on the lower layer film on the transparent substrate,

The semi-transmissive portion is formed by forming the underlayer film on the transparent substrate, and further includes a first semi-transmissive portion formed adjacent to the first edge of the light-shielding portion, and a second opposing the first edge of the light-shielding portion. Each having a second translucent portion formed adjacent to an edge,

A photomask is provided in which a difference between the line width of the first semi-transmissive portion and the line width of the second semi-transmissive portion is 0.1 μm or less.

According to a tenth aspect of the present invention,

The underlayer film is provided with the photomask according to the eighth or ninth aspect, which has a transmittance of 2 to 90% with respect to the representative wavelength contained in the exposure light, and the amount of phase shift with respect to the representative wavelength is approximately 180 degrees.

According to the eleventh aspect of the present invention,

The underlayer film has a transmittance of 2 to 60% with respect to the representative wavelength included in the exposure light, and furthermore, the photomask according to the eighth or ninth aspect, wherein the amount of phase shift with respect to the representative wavelength exceeds 0 ° and is 90 ° or less. Is provided.

According to a twelfth aspect of the present invention,

Any one of i-line, h-line, and g-line is used using the photomask by the manufacturing method in any one of 1st-7th, or the photomask in any one of 8th-10th. By the exposure apparatus which has an exposure light source containing, the pattern transfer method which transfers the said transfer pattern on a to-be-transferred body is provided.

According to a thirteenth aspect of the present invention,

Any one of i-line, h-line, and g-line is used using the photomask by the manufacturing method in any one of 1st-7th, or the photomask in any one of 8th-10th. The manufacturing method of the flat panel display which has a process of transferring the said transfer pattern on a to-be-transferred body is provided by the exposure apparatus which has an exposure light source which contains.

According to the present invention, it is possible to provide a photomask having a fine and highly accurate transfer pattern, a manufacturing method thereof, a pattern transfer method using such a photomask, and a manufacturing method of a flat panel display.

1 is a flow chart showing a conventional method for manufacturing a phase shift mask.
2 is a partially enlarged view of a phase shift mask manufactured by a conventional method.
3 is a flow chart for explaining a method for manufacturing a photomask according to one embodiment of the present invention.
Fig. 4A is a sectional enlarged view of a photomask according to an embodiment of the present invention, and Fig. 4B is a top SEM image thereof.
5 is a top view illustrating a configuration example of a transfer pattern of a photomask according to an embodiment of the present invention.
Fig. 6 is a top view showing another configuration example of the transfer pattern of the photomask according to the embodiment of the present invention.
Fig. 7 is a top view showing a structural example of a transfer pattern of a photomask manufactured by a conventional method.
Fig. 8 is a top view showing another configuration example of a transfer pattern of a photomask manufactured by a conventional method.
9 is a top view of a transfer pattern of a binary photomask (comparative example).
Fig. 10 is a top view of a transfer pattern of a photomask (embodiment) configured as a phase shift mask.
FIG. 11 is a diagram showing the intensity distribution of transmitted light transmitted through the photomasks shown in FIGS. 9 and 10.
Fig. 12 is a top view of a transfer pattern of a photomask (example) constructed as a transmission assisted photomask.
Fig. 13 is a top view of a transfer pattern of a binary photomask (comparative example).
Fig. 14 is a diagram showing the intensity distribution of transmitted light transmitted through the photomasks shown in Figs. 11 and 12, respectively.
15 is a graph showing the relationship between the amount of alignment misalignment and the intensity distribution of transmitted light.

The manufacturing method of the phase shift mask of patent document 1 is to pattern a light shielding layer on a transparent substrate, to form a phase shift layer on a transparent substrate so that this light shielding layer may be coat | covered, and to pattern this phase shift layer. The manufacturing process disclosed in patent document 1 is shown in FIG.

First, the light shielding layer 11 is formed on the transparent substrate 10 (FIG. 1A), and then the photoresist layer 12 is formed on the light shielding layer 11 (FIG. 1 ( B)). Subsequently, the resist pattern 12P1 is formed on the light shielding layer 11 by exposing and developing the photoresist layer 12 (FIG. 1C). Using the resist pattern 12P1 as an etching mask, the light shielding layer 11 is etched in a predetermined pattern shape. Thereby, the light shielding layer pattern 11P1 patterned by the predetermined shape is formed on the transparent substrate 10 (FIG. 1D). After the resist pattern 12P1 is removed (FIG. 1E), the phase shift layer 13 is formed. The phase shift layer 13 is formed on the transparent substrate 10 so that the light shielding layer pattern 11P1 may be coat | covered (F of FIG. 1).

Then, the photoresist layer 14 is formed on the phase shift layer 13 (FIG. 1G). Next, the resist pattern 14P1 is formed on the phase shift layer 13 by exposing and developing the photoresist layer 14 ((H) of FIG. 1). Using the resist pattern 14P1 as an etching mask, the phase shift layer 13 is etched in a predetermined pattern shape. Thereby, the phase shift layer pattern 13P1 patterned by the predetermined shape is formed on the transparent substrate 10 (FIG. 1 (I)).

After formation of the phase shift layer pattern 13P1, the resist pattern 14P1 is removed (FIG. 1J). As described above, the phase shift mask 1 in which the phase shift layer pattern 13P1 is formed around the light shielding layer pattern 11P1 is manufactured.

However, according to the examination of the present inventors, the following subjects may arise when it is going to manufacture a high precision photomask by this method. That is, between exposure of the photoresist layer 12 (that is, the first drawing process (FIG. 1C) and exposure of the photoresist layer 14 (that is, the second drawing process (FIG. 1H)). It is impossible to make the alignment misalignment mutually zero, which may cause alignment misalignment between the light shielding layer pattern 11P1 and the phase shift layer pattern 13P1.

FIG. 2 is a partially enlarged view (expanded view of the broken line portion) of the phase shift mask 1 described in FIG. 1J. When the alignment misalignment occurs, the dimension A and the dimension B shown in FIG. 2 are different. That is, in the line width direction, the function of the phase shift layer becomes asymmetric. In some cases, in this pattern, a phase shift effect is strongly shown on one side of the line width direction, and a transfer image (light intensity distribution due to light passing through the photomask) is generated on the other side of the phase shift effect. There is a case. When a flat panel display is manufactured using a photomask having such a transfer pattern, control of the line width is lost, and a circuit pattern with high precision is not obtained.

In a photomask manufactured through a plurality of photolithography steps, a plurality of patterning operations are performed while referring to a common alignment mark or the like, whereby an effort for eliminating the gap deviation can be made. However, due to the coordinate accuracy of the drawing machine, the handling performance of the photomask, and the like, it is not easy to make the alignment shift 0.5 μm or less. The line width variation due to such alignment misalignment is very serious in the pattern of fine line width (for example, 1.0 μm or less), and the pattern having a line width of 0.5 μm or less cannot be stably formed.

Therefore, the present inventors examined the manufacturing method of the photomask which can control line width precisely even if it is a fine line width. EMBODIMENT OF THE INVENTION Below, one Embodiment of this invention is described.

(Production method of photomask)

First, the manufacturing method of the photomask 100 which concerns on one Embodiment of this invention is demonstrated.

As the manufacturing method of the photomask 100 which concerns on this embodiment is illustrated in FIG.

As a manufacturing method of the photomask 100 provided with the transfer pattern in which the lower layer film 20 and the upper layer film 30 which were formed on the transparent substrate 10 were respectively patterned,

Preparing a photomask blank 100b on which the lower layer film 20 and the upper layer film 30 are formed on the transparent substrate 10,

An upper layer film pre-etching step of etching the upper layer film 30 using the resist pattern 40p formed on the upper layer film 30 as a mask;

An underlayer film patterning process of etching the underlayer film 20 by using the resist pattern 40p or the etched upper layer film 30a as a mask to form the underlayer film pattern 20p;

An upper layer film patterning process is performed in which the upper layer film 30a is side-etched using the resist pattern 40p as a mask to form the upper layer film pattern 30p.

Here, as the transparent substrate 10, a quartz glass substrate having a polished surface is used. The size is not particularly limited, and the size is appropriately selected depending on the substrate (for example, a substrate for flat panel display, etc.) exposed using the mask or the use. For example, a rectangular substrate of 300 mm or more on one side is used.

In this embodiment, the photomask blank 100b by which the lower layer film 20 and the upper layer film 30 were laminated | stacked on this transparent substrate 10 in this order is prepared.

The upper layer film 30 and the lower layer film 20 are preferably materials having resistance to each etchant (etching liquid or etching gas). In addition, since the side etching is performed about the upper layer film 30 in the upper layer film patterning process mentioned later, as a raw material of the upper layer film 30, it is preferable to use the raw material suitable for wet etching with a big tendency of isotropic etching.

In addition, when the underlayer film 20 mounts the photomask 100 of this embodiment to an exposure machine and exposes, it is preferable that it is a semi-transmissive film which permeate | transmits the exposure light partially. Specific examples of the material of the lower layer film 20 include Cr compounds (oxides, nitrides, carbides, oxynitrides, oxynitrides, and the like) of Cr, Si compounds (SiO ₂ , SOG), and metal silicide compounds (TaSi, MoSi, WSi). Or their nitrides, carbides, oxynitrides, oxynitrides and the like).

Specific examples of the material of the upper layer film 30 include, in addition to Cr or Cr compounds (oxides, nitrides, carbides, oxynitrides, oxynitrides, and the like) of Cr, Ta, W or their compounds (including the metal silicides), and the like. Can be mentioned.

It is preferable that the upper layer film 30 and the lower layer film 20 do not substantially transmit the exposure light in the stacked state (the optical density OD is 3 or more), but depending on the use of the photomask 100, It is also possible to transmit a part of the exposure light (for example, transmittance ≤ 20%). In the present embodiment, as an example, the upper layer film 30 will be described as a light shielding film having an optical density (OD) of 3 or more, and the lower layer film 20 is a semi-transmissive film that partially transmits the exposure light. In addition, the preferable transmittance | permeability range and phase shift characteristic of the underlayer film 20 are mentioned later.

In addition, as long as it is a layer structure to which the manufacturing method of this invention is applicable, the case where another film is formed on the transparent substrate 10 other than the upper layer film 30 and the lower layer film 20 is not excluded. For example, other films, such as an etching stopper film, may be formed in the interface of the upper layer film 30 and the lower layer film 20, another film may be formed in the upper surface of the upper layer film 30, and the lower layer film 20 Another film may be formed on the lower surface.

The photomask blank 100b in which the lower layer film 20 and the upper layer film 30 were formed is further apply | coated the resist film 40 on the upper layer film 30, and is used as a photomask blank by which resist was apply | coated. Then, a predetermined pattern is drawn to the blank resist film 40 using a drawing machine (Fig. 3 (A)). Although the resist film may be positive type or negative type, it demonstrates positive type in this aspect.

Subsequently, the resist film 40 is developed to form a resist pattern 40p (FIG. 3B).

Then, using the resist pattern 40p as a mask, a step of preliminarily etching the upper layer film 30 (upper layer preliminary etching step) is performed (FIG. 3C). This preliminarily etched upper layer film 30 is referred to as upper layer film 30a in FIG. 3. When the upper layer film 30 is a Cr light shielding film (light shielding film mainly composed of Cr or Cr compound), an etching solution containing dicerium ammonium nitrate known as an chromium etchant can be used. Moreover, you may apply the dry etching using the etching gas of chlorine gas. This Cr light shielding film may have a structure having an antireflection layer made of a Cr compound on its surface.

Thereafter, the step of continuously etching the lower layer film 20 using the resist pattern 40p and the preliminarily etched upper layer film 30a as a mask without removing the resist pattern 40p (underlayer film) Patterning process) (FIG. 3D). When the lower layer film 20 is a MoSi-based material, an etching solution in which oxidizing agents such as hydrogen peroxide, nitric acid and sulfuric acid are added to fluorine compounds such as hydrofluoric acid, hydrofluoric acid and ammonium bifluoride can be used. Moreover, you may apply dry etching using a fluorine-type etching gas.

Next, the process (side film patterning process) of side-etching the upper film 30a is performed again without removing the resist pattern 40p. Here, the above-mentioned wet etchant for chromium can be used. Since wet etching tends to etch the target film isotropically, the edge portion of the upper layer film 30a is eluted in the horizontal direction under the resist pattern 40p (FIG. 3E). By the side etching of the light shielding film, the edge of the translucent film is exposed. It is preferable that the width | variety of this exposed part shall be 0.1-1.0 micrometer.

In addition, wet etching is applied to this side etching process (upper layer patterning process), and dry etching may be applied to the other etching process. Preferably, in the etching step, it is convenient for equipment to apply wet etching to all.

After the upper layer film patterning step, the resist pattern 40p is removed to complete the manufacture of the photomask 100 according to the present embodiment (FIG. 3F).

(Configuration of Photomask)

Next, the structure of the photomask 100 manufactured by the method mentioned above is demonstrated. FIG. 4A shows a cross-sectional enlarged view of the photomask 100 according to the present embodiment, and FIG. 4B shows an upper SEM image (partially enlarged view) thereof.

As shown in FIG. 4, the photomask 100 according to the present embodiment includes a light transmitting part 103 and a light blocking part formed by patterning the lower layer film 20 and the upper layer film 30 on the transparent substrate 10, respectively. 102, a photomask 100 having a transfer pattern comprising translucent portions 101a, 101b,

The light transmitting part 103 is formed by exposing the transparent substrate 10,

The light shielding portion 102 is formed by laminating the upper layer film 30 (the upper layer film pattern 30p) on the lower layer film 20 (the lower layer film pattern 20p) on the transparent substrate 10,

The semi-transmissive portions 101a and 101b are formed by forming an underlayer film 20 (lower layer film pattern 20p) on the transparent substrate 10 and further, 1.0 μm formed adjacent to the edge of the light shielding portion 102. It has a part of the following fixed line width, It is characterized by the above-mentioned.

There is no restriction | limiting in particular in the said fixed line width, It is advantageous that it is the fine line width of about 0.1-1.0 micrometer, for example.

4, in the photomask 100 which concerns on this embodiment, the upper layer film pattern 30p is located in the center of the horizontal direction of the lower layer film pattern 20p. A portion of the lower layer pattern 20p is exposed at a constant width adjacent to the edge of the upper layer pattern 30p.

The photomask 100 of the present invention includes the following aspects. In other words,

"The transfer pattern including the light-transmitting part 103, the light-shielding part 102, and the translucent part 101a, 101b formed by patterning the lower layer film 20 and the upper layer film 30 on the transparent substrate 10, respectively is provided. As one photomask 100,

The light transmitting part 103 is formed by exposing the transparent substrate 10,

The light shielding portion 102 is formed by laminating the upper layer film 30 (the upper layer film pattern 30p) on the lower layer film 20 (the lower layer film pattern 20p) on the transparent substrate 10,

The translucent portions 101a and 101b are formed by forming an upper layer film 30 (upper layer pattern 30p) on the transparent substrate 10 and are formed adjacent to the first edge of the light shielding portion 102. Each having a first semi-transmissive portion 101a and a second semi-transmissive portion 101b formed adjacent to a second edge facing the first edge of the light-shielding portion 102,

The difference between the line width of the first translucent portion 101a and the line width of the second translucent portion 101b is 0.1 µm or less.

More preferably, the difference between the line width of the first translucent portion 101a and the line width of the second translucent portion 101b is 0.01 µm or more and 0.1 µm or less.

Or the following aspect is also included. In other words,

"The transfer pattern including the light-transmitting part 103, the light-shielding part 102, and the translucent part 101a, 101b formed by patterning the lower layer film 20 and the upper layer film 30 on the transparent substrate 10, respectively is provided. As one photomask 100,

The light transmitting part 103 is formed by exposing the transparent substrate 10,

The light shielding portion 102 is formed by laminating the upper layer film 30 (the upper layer film pattern 30p) on the lower layer film 20 (the lower layer film pattern 20p) on the transparent substrate 10,

The translucent portions 101a and 101b are formed by forming an upper layer film 30 (upper layer pattern 30p) on the transparent substrate 10, and are formed adjacent to the first edge of the transmissive portion 103. Each of the first semi-transmissive portion 101a and the second semi-transmissive portion 101b formed adjacent to the second edge opposite to the first edge of the transmissive portion 103,

The difference between the line width of the first semi-transmissive portion 101a and the line width of the second semi-transmissive portion 101b is 0.1 µm or less.

That is, the semi-transmissive portions 101a and 101b are adjacent to the edges of the light-shielding portion 102 and adjacent to the edges of the light-transmitting portion 103. Also in this case, it is preferable that the difference of the line width of the 1st semi-transmissive part 101a and the line width of the 2nd semi-transmissive part 101b is 0.01 micrometer or more and 0.1 micrometer or less, for example.

In FIG. 4A, the translucent portions 101a and 101b are formed adjacent to each of the two opposite edges of the predetermined light shielding portion 102. When these are made into the 1st semi-transmissive part 101a and the 2nd semi-transmissive part 101b, they are formed symmetrically about the light shielding part 102, and the line width inconsistency is substantially prevented. That is, the deviation of the line width of the second semi-transmissive portion 101b with respect to the line width of the first semi-transmissive portion 101a can be within 0.1 μm. More preferably, it can be within 0.05 micrometers. In addition, it is possible to make the line width precision of the transflective part 101a, 101b within the said range in the whole transfer pattern with which the photomask 100 is equipped. Therefore, the effect of this embodiment becomes remarkable when the line width of the 1st semi-transmissive part 101a and the line width of the 2nd semi-transmissive part 101b are both 1.0 micrometer or less (0.1-1.0 micrometer).

Here, the shape of the transfer pattern, that is, the shape of the upper layer pattern 30p and the lower layer pattern 20p may be determined according to the use of the photomask 100. For example, a photomask 100 having a line-and-space pattern (hereinafter sometimes referred to as an "L / S pattern") as shown in FIG. 5 or a hole pattern as shown in FIG. 6 as a transfer pattern can be manufactured. At this time, this embodiment can be advantageously applied. As shown in FIG. 5, in the case of a line and space pattern, a light shielding portion 102 is disposed at the center of the line pattern, and a semi-transparent semi-transparent width is provided at the edge portion of the line pattern, that is, the boundary portion with the space pattern. Mining portions 101a and 101b are formed. As shown in FIG. 6, in the case of the hole pattern, semi-transmissive portions 101a and 101b having a predetermined width are formed at the edges of the holes opened in the light shielding portion 102. The hole pattern may be an isolated hole pattern or a dense hole pattern. The dense hole pattern refers to a transfer pattern in which patterns of the same shape are regularly arranged and mutually transmitted light interferes with each other. The isolated hole pattern does not constitute such an arrangement of the same shape pattern. Say.

The width of the part where the lower layer film pattern 20p is partially exposed may be 1/2 or less of the line width of the upper layer film pattern 30p. However, when the width | variety of this part is 0.1 micrometer-1.0 micrometer as mentioned above, the effect of this embodiment becomes remarkable. In particular, the width of the exposed portion of the lower layer film pattern 20p (when the lower layer film 20 is a translucent film, this portion becomes the line width of the translucent portions 101a and 101b in the photomask 100) When it is 1.0 micrometer or less, the effect of this embodiment becomes remarkable. It is because such a dimension is a dimension which is difficult to obtain uniformly by the conventional methods, such as the method of patent document 1 mentioned above. Moreover, when the width of this part is 0.1 micrometer or more, the optical function as a transfer pattern of the photomask 100 is advantageously exhibited.

(When used as a phase shift mask)

When the lower layer film 20 is configured as the phase shift film and the upper layer film 30 as the light shielding film, the photomask 100 according to the present embodiment can be used as the phase shift mask. At this time, the lower layer film 20 is a film having a transmittance of, for example, 2 to 90% with respect to the representative wavelength included in the exposure light, preferably 2 to 60%, more preferably 2 to 30%. It is set as a membrane having a transmittance. Moreover, it is preferable to set it as the film | membrane so that the phase shift amount with respect to the said representative wavelength may be set to about 180 degrees. About 180 degrees means that it is 180 +/- 30 degrees. More preferably, you may be 180 degrees +/- 10 degrees.

In the phase shift mask, the phase of the light (light of the representative wavelength) passing through the light transmitting part 103 and the lower layer film 20 (lower layer film pattern 20p) are formed on the transparent substrate 10. By mutually shifting the phase of the light transmitted through the translucent portions 101a and 101b (light of the representative wavelength) by approximately 180 °, mutual interference of the light is prevented at the boundary between the translucent portions 101a and 101b and the transmissive portion 103. Can be produced, and the contrast on the transfer can be improved. The phase shift amount φ (rad) of the light passing through the translucent portions 101a and 101b depends on the refractive index (complex refractive index actual portion) n and the film thickness d of the underlayer film 20 used therein, Relationship is established.

Is the wavelength of the exposure light.

Therefore, in order to shift the phase 180 degrees, the film thickness d of the translucent film is

. By this phase shift mask, an increase in the depth of focus for obtaining the required resolution can be achieved, and the resolution and process applicability can be improved without changing the exposure wavelength.

9 shows a line and space pattern of a binary mask (a mask in which only a light shielding film pattern is formed on a transparent substrate). 10 shows that a phase shift portion having a predetermined width is formed at the edge of the line portion as an L / S pattern having the same pitch as in FIG. 9. In addition, the transfer pattern of FIG. 10 can be manufactured by the manufacturing method of this embodiment.

FIG. 11 shows a light intensity curve received by the transfer target body when the transfer pattern in FIGS. 9 and 10 are transferred onto the transfer target body respectively using the LCD exposure apparatus. The vertical axis | shaft of FIG. 11 has shown the light transmittance intensity, and the horizontal axis | shaft has shown the transfer position on a to-be-transferred body. The dotted line of FIG. 11 shows the light transmission intensity of the light which permeate | transmitted the phase shift mask (Example) of FIG. 10, and the solid line shows the light transmission intensity of the light which permeated the binary mask (comparative example) of FIG. According to FIG. 11, in the phase shift mask of FIG. 10, since the anti-phase diffraction light interferes at the boundary of a space part and a line part, it turns out that contrast improves and excellent pattern precision is obtained.

In addition, if the pattern of FIG. 10 has a pattern shift as shown in FIG. 7, since the interference effect obtained at both edges of a line pattern becomes asymmetric, the precision of the pattern obtained on a to-be-transferred body deteriorates.

The phase shift mask of FIG. 10 is what has already been obtained by making the lower layer film 20 of this embodiment consist of a phase shift film, and making the upper layer film 30 of this embodiment consist of a light shielding film. Here, as a preferable phase shift film, although exposure light is shifted by approximately 180 degrees, when exposure light contains multiple wavelengths (for example, when using the light source containing i line | wire, h line | wire, and g line | wire), As a representative wavelength, it is assumed that there is a phase shift action of approximately 180 ° with respect to any one of these wavelengths.

Here, for example, the phase shift amount of 180 ° means that the phase difference between light transmitting only the transparent substrate 10 and light passing through the transparent substrate 10 and the lower layer film 20 is 180 °. Radian notation results in (2n + 1) π, where n = 0, 1, 2,...

(When used as a penetration assisting mask)

In addition, as another aspect of the photomask 100 of the present embodiment, the underlayer film 20 has a transmittance of 2 to 60% with respect to the representative wavelength included in the exposure light, and also a phase shift with respect to the representative wavelength. It may be comprised as a film | membrane whose amount exceeds 0 degrees and is 90 degrees or less. The underlayer film 20 in this case has a function of assisting the amount of transmitted light of the light transmitting part 103 rather than a function of improving the contrast by exerting the above phase shift effect (hereinafter, such a film is also referred to as a transmission auxiliary film). ). For example, in the photomask 100 which concerns on this embodiment shown in FIG. 4, by making the lower layer film pattern 20p into this transmission auxiliary film pattern, the amount of transmitted light of the transmissive part 103 can be assisted. Details are described in the examples.

Such a photomask 100 has an effect similar to that of increasing the irradiation light amount of an exposure apparatus, and brings remarkable merit to energy saving, shortening of exposure time, and improvement of productive efficiency.

The function of assisting the light amount can not be sufficiently exhibited if the transmittance is very small, and if the transmittance is too large, the contrast of the transfer image is degraded. Therefore, the transmittance of the underlayer film 20 is in the range of 2 to 60%. Moreover, the preferable range of the transmittance | permeability of the underlayer film 20 is 10 to 45%, More preferably, it is 10 to 30%, More preferably, it is 10 to 20%.

In addition, when the amount of phase shift is excessively small, selection of the material constituting the lower layer film 20 (semi-transmissive film) is not easy. When the amount of phase shift is excessively large, interference of light in the reverse phase occurs. In consideration that the auxiliary effect of the amount of transmitted light is impaired, it is preferable to select the material and the film thickness of the film. The range of the phase shift amount of the lower layer film 20 exceeds 0 ° and is 90 ° or less (this is (2n-1 / 2) π to (2n + 1/2) π (n is an integer) when expressed in radians). ), Preferably 5 to 60 degrees, more preferably 5 to 45 degrees.

An upper surface configuration is shown in FIG. 12 for a structural example of the photomask having the light quantity assist function. Here, the line-and-space pattern of pitch 6 micrometers (3 micrometers of line parts, 3 micrometers of space parts) is illustrated. The center of a line part consists of a light shielding part of width 2micrometer, and the transflective part (HT part) of width 0.5micrometer (total 1.0micrometer) is formed adjacent to the edge of both sides, respectively. FIG. 14 shows the intensity distribution curve (simulation result) of transmitted light when such a transfer pattern is exposed by an LCD exposure machine. The vertical axis in Fig. 14 represents the light transmission intensity, and the horizontal axis represents the transfer position on the transfer object. The solid line of FIG. 14 shows the light transmission intensity of the light which permeate | transmitted through the transmission assist type | mold photomask (Example) of FIG. 12, and the dotted line shows the light transmission of the light which transmitted the binary mask (comparative example) of the same dimension as described in FIG. The strength is shown. According to FIG. 14, it is understood that the amount of transmitted light of the light transmitting portion corresponding to the space portion is increased in the transmission assist type photomask of FIG. 12.

The photomask which has such a function is especially favorable with refinement | miniaturization of a pattern. As the line width of the light-transmitting portion narrows, the amount of transmitted light in the portion decreases (the peak portion in FIG. 14 goes down), and when the photosensitive threshold value of the resist film formed on the transfer object is not reached, the function of the resist pattern serving as an etching mask is achieved. This is because it becomes difficult to exert.

If alignment misalignment as illustrated in FIG. 7 occurs between the upper layer pattern and the lower layer pattern, the transfer position (pattern position) on the transfer member is shifted, and the peak light amount of the light transmitting portion is lowered, so that the transfer accuracy is reduced. It will be damaged. This state is shown in FIG. 15 represents the intensity of transmitted light on the transfer target, and the abscissa represents the transfer position on the transfer target. In FIG. 15, the transmission light intensity distribution in the case where there is no alignment misalignment is shown by "curve AL_E0", and the transmission light intensity distribution in the case where alignment misalignment of 0.1-0.5 micrometer arises is shown by "curve AL_E0.1-0.5", respectively. According to FIG. 15, it turns out that the photomask 100 which concerns on this embodiment is a photomask excellent in the transfer performance which does not produce such a problem.

In addition, it was confirmed that such an effect is obtained not only in the line and space pattern but also in the hole pattern.

That is, the optical effect by the lower layer film 20 exposed on both sides of the upper layer film 30 is based on the design value even if it is a phase shift effect, a light quantity assisting effect, or an effect by another optical behavior. Therefore, it is required to generate symmetrically in the line width direction. Here, when the photomask is manufactured using a plurality of photolithography steps as in the method disclosed in Patent Document 1, it is impossible to zero the mutual alignment misalignment of the mutual patterns (upper layer pattern and lower layer pattern), Alignment misalignment about 0.3 micrometer or more generate | occur | produces.

On the other hand, in this embodiment, two film patterns are formed using the resist pattern 40p drawn in one drawing process. Thereby, generation | occurrence | production of alignment misalignment between the upper layer film pattern 30p and the lower layer film pattern 20p can be prevented. As a result, it is possible to generate optical effects such as a phase shift effect and a light quantity assist effect symmetrically in the line width direction based on the design value. Moreover, the efficiency of a production process can also be aimed at by reducing the number of photolithography processes to one. That is, a photomask having a high optical function as described above can be obtained with high productivity.

In addition, there is no restriction | limiting in particular in the exposure apparatus used when pattern transfer is carried out on a to-be-transferred object using the photomask 100 which concerns on this embodiment. However, the photomask 100 which concerns on this embodiment can be used especially suitably, when exposing using the exposure apparatus for LCD which has a light source containing i line | wire, h line | wire, and g line | wire.

In addition, in the photomask 100 which concerns on this embodiment using the phase shift film pattern, you may expose using only a single wavelength (for example, i line | wire) among said wavelengths. Moreover, when the exposure resolution limit of an exposure apparatus is 3 micrometers or more, the effect of using the photomask 100 of this embodiment becomes especially remarkable.

Moreover, in the photomask 100 which concerns on this embodiment using the permeation | transmission auxiliary membrane, it is also possible to shorten the time required for the scanning exposure at the time of transferring a pattern to a to-be-transferred body. This is because such photomask 100 has an effect similar to increasing the amount of irradiation light of an exposure apparatus. In particular, in the case of using as a photomask when manufacturing a display device (flat panel display or the like) having a relatively large area of the transfer object (for example, 1000 mm to 3100 mm), a particularly advantageous effect is obtained.

10: transparent substrate
20: underlayer film
20p: underlayer pattern
30: upper layer
30a: preetched top layer
30p: upper layer pattern
40: resist film
40p: resist pattern
100: photomask
100b: photomask blank
101a: first translucent part
101b: second translucent portion
102: light shield
103: floodlight

Claims (2)

Preparing a photomask having a transfer pattern;
A pattern transfer method comprising the step of transferring the transfer pattern onto a transfer object by an exposure apparatus,
The transfer pattern includes a light-transmitting portion, a light-shielding portion, and a semi-transmissive portion formed by patterning a lower layer film and an upper layer film respectively formed on a transparent substrate,
The light transmitting portion is formed by exposing the transparent substrate,
The light shielding portion is formed by laminating an upper layer film on the lower layer film on the transparent substrate,
The semi-transmissive portion is formed with the lower layer film formed on the transparent substrate, and has a portion having a predetermined line width of 1.0 μm or less formed adjacent to an edge of the light shielding portion,
The pattern transfer method characterized by using the exposure light containing i line | wire, h line | wire, and g line | wire in the process of transferring the said transfer pattern. Preparing a photomask having a transfer pattern;
A manufacturing method of a flat panel display comprising the step of transferring the transfer pattern onto a transfer object by an exposure apparatus,
The transfer pattern includes a light-transmitting portion, a light-shielding portion, and a semi-transmissive portion formed by patterning a lower layer film and an upper layer film respectively formed on a transparent substrate,
The light transmitting portion is formed by exposing the transparent substrate,
The light shielding portion is formed by laminating an upper layer film on the lower layer film on the transparent substrate,
The semi-transmissive portion is formed with the lower layer film formed on the transparent substrate, and has a portion having a predetermined line width of 1.0 μm or less formed adjacent to an edge of the light shielding portion,
The manufacturing method of the flat panel display characterized by using the exposure light containing i line | wire, h line | wire, and g line | wire in the process of transferring the said transfer pattern.

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