KR101414343B1 - Method of manufacturing a photomask, photomask, pattern transfer method, and method of manufacturing a flat panel display - Google Patents

Abstract

A method of manufacturing a photomask, a photomask using the same, and a transfer method, in which, when a multi-grayscale photomask is manufactured, the accuracy of the final product can be obtained without lowering the production efficiency despite the positional deviation of each pattern, And a method of manufacturing a flat panel display.
A method of manufacturing a multi-gradation photomask comprising a transparent substrate and a transfer pattern including a light-transmitting portion, a light-shielding portion, a first translucent portion, and a second translucent portion, wherein the first translucent portion includes a first translucent film And the second translucent portion is formed on the transparent substrate with a second translucent film having an exposure light transmittance different from that of the first translucent film, and the first translucent portion and the second translucent portion are formed on adjacent portions A step of preparing a photomask blank in which a first semi-light-transmitting film and a light-shielding film are laminated on a transparent substrate and a first resist film is further formed; A first etching step of etching the light shielding film and the first translucent film using the first resist pattern as a mask, and a second etching step of etching the first translucent film after the first etching step, A step of forming a second semi-light-transmitting film and a second resist film on the body surface, a step of forming a second resist pattern by performing a second drawing on the second resist film, A second etching step of etching the first and second semitransparent films and the first and second semitransparent films and the second semitransparent film after the second etching step, The drawing data of the first drawing or the second drawing is formed so as to have the overlap as much as possible.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a photomask manufacturing method, a photomask, a pattern transfer method, and a flat panel display manufacturing method.

The present invention relates to a photomask having a transfer pattern, in particular, a method of manufacturing a multi-gradation photomask, a photomask using the same, a pattern transfer method using the photomask, and a flat panel display using a pattern transfer method Panel display).

In recent years, a multi-gradation photomask having a semi-light-transmitting portion which partially transmits exposure light has been industrially used in addition to the light-shielding portion and the light-projecting portion.

Patent Document 1 describes a manufacturing method of a photomask having four gradations. According to this, the light shielding portion, the light projecting portion, the first translucent portion, and the second translucent portion (the first translucent portion and the second translucent portion have different light transmittances) can be produced by two drawing processes.

Patent Document 2 relates to a method of manufacturing a gray tone mask using a halftone film. In a first photolithography process and a second photolithography process, So that positional deviation occurs. In order to cope with this, there is described a manufacturing method of performing a light-shielding portion pattern forming step and then a semi-transparent portion pattern forming step of forming a translucent portion and a light-transmitting portion.

Japanese Patent Application Laid-Open No. 2007-249198 Japanese Patent Application Laid-Open No. 2005-37933

According to Patent Document 1, as shown in Fig. 1, it is possible to manufacture a photomask having four grayscales by using only two imaging processes. By applying this method, compared with a three-tone photomask, There is no case in which the load of the motor is greatly increased. However, occurrence of misalignment at the mutual positions of the two drawing processes shown in Figs. 1B and 1G can not be completely prevented.

On the other hand, the method described in Patent Document 2 is effective for a multi-gradation photomask of three gradations, but it can not be applied to a multi-gradation type photomask including a plurality of semi-light-projecting portions. For example, based on the method described in Patent Document 2, a problem in the case of manufacturing a 4-gradation photomask will be described with reference to FIG.

First, a multi-gradation photomask blank prepared by laminating a first semi-light-transmitting film and a light-shielding film in this order on a transparent substrate and further forming a first resist film is prepared (FIG. 2A) Reference). Here, the resist may be either a positive type or a negative type, but the resist will be described as a positive type. Subsequently, a first resist pattern is formed on the blank by performing a first drawing operation using a drawing machine and developing the first drawing pattern (see FIG. 2 (b)). This resist pattern covers the formation region of the first semi-light-transmitting portion and the light-shielding portion formation region.

Then, the light shielding film is etched using the first resist pattern as a mask (see FIG. 2 (c)). Further, the first semi-light-transmitting film is subsequently etched (see Fig. 2 (d)). The etching of the light-shielding film and the first semi-light-transmitting film may be either wet etching or dry etching.

After the etching of the first semi-light-transmitting film is completed, the first resist pattern is peeled off (see Fig. 2 (e)). Then, a second semi-light-transmitting film is formed on the entire surface including the formed light-shielding film pattern and the first semi-light-transmitting film pattern (see Fig. 2 (f)). Then, the second resist is applied to form a second resist film (see Fig. 2 (g)).

Subsequently, the second resist film is subjected to second imaging and developed to obtain a second resist pattern. This resist pattern covers the formation region of the second semi-transparent portion and also covers the light-shielding portion formation region (see (h) of FIG. 2).

Then, the second semi-light-transmitting film is etched using the second resist pattern as a mask to form a light-transmitting portion, and the laminated portion of the second semitransparent film and the light-shielding film is etched to expose the first semi- (i)).

Then, the second resist pattern is peeled off to complete the 4-gradation photomask (see FIG. 2 (j)).

However, in practice, the relative positional accuracy of the first imaging and the second imaging is not perfect. That is, when the first drawing operation is completed and the substrate taken out of the drawing apparatus is once subjected to development, etching, film formation, and the like, and then set again in the drawing apparatus, Even if positioning is performed, it is difficult to perfectly align the alignment of the two substrates. It is also not easy to completely coincide the coordinates of the first and second drawing points on the whole surface with respect to the coordinate accuracy of the drawing device. As a result, there are cases where the first and second drawing positions for an arbitrary position on the substrate are shifted in the range of about 0.5 mu m (hereinafter, also referred to as " alignment displacement " .

The transfer pattern formed by the above-described alignment displacement will be described with reference to Fig. 3 (a) shows a transfer pattern shown as an ideal state, and shows a case where a transfer pattern to be obtained is formed as designed. However, in reality, the second resist pattern is displaced relative to the first resist pattern. Fig. 3 (b) shows a case of shifting left (shifted), and Fig. 3 (d) shows a case of right shifting. In this state, if etching is performed based on the above-described process, as shown in (c) or (e) of FIG. 3, the boundary portion between the first translucent portion and the second translucent portion is different from the design Shape is formed.

That is, in FIG. 3 (c) in the case of shifting to the left, a gap (hereinafter also referred to as a "slit") between the first and second semi-light-transmitting films is formed at the boundary.

In Fig. 3E in the case of shifting to the opposite (right) side, a portion (also referred to as a "line") in which the first and second semi-light-transmitting films overlap is formed at the boundary.

However, since the alignment deviation is within ± 0.5 占 퐉 as described above, the width is 0.5 (mm), as described above, although the separation (slit) or the overlapping (line) reflects the alignment deviation and is formed as a part of the transfer pattern. Mu m or less. Therefore, the resolution is lower than the resolution limit of the exposure apparatus, so that an unnecessary pattern is not formed on the transferred object or a problem occurs in the final device.

The intensity distribution of the transmitted light when transferring the transfer pattern to the transfer target body by the above-described separation (slit) or overlapping (line) is shown in Figs.

Fig. 4 is a graph showing the light intensity distribution on the transferred body when a gap (slit) is formed with the boundary being spaced apart. Fig. This was also obtained by the present inventors by a simulation under the following conditions.

That is, the exposure optical condition is a broad wavelength light source having an NA of 0.085, sigma (Sigma: Coherence) of 0.9, and including a g line, h line and i line, : i = 1: 0.8: 0.95. When the transmittance of the transparent substrate was taken as 100%, the transmittance of the first semitransparent film was 60% and the transmittance of the second semitransparent portion was 10%. The amount of phase shift of the semitransparent film was set to 30 degrees.

4 shows the case where a gap (slit) of 0.5 mu m is formed in the case of no gap (0 mu m), that is, an ideal manufacturing process, and a case where a gap And a light intensity distribution, respectively.

4, when the gap (slit) of 0.5 占 퐉 or 1.0 占 퐉 is formed, the inclination of the boundary portion in the light intensity distribution does not substantially change from the case of the ideal type (0 占 퐉) (In the case of perpendicular to the substrate surface, the inclination angle becomes maximum, which is slightly increased). In other words, the formation of the gap (slit) itself does not cause a large problem of the transferring phase, and rather the profile of the resist pattern is advantageous as an etching mask (the inclination angle of the cross section of the resist pattern is large) .

Fig. 5 is a graph showing the light intensity distribution on the transferred body when overlapping (line) is formed at the boundary. Fig. The simulation conditions shown in Fig. 5 are the same as those in the simulation shown in Fig.

5 shows the case where no overlapping (line) (0 占 퐉) is achieved, that is, when an overlapping (line) of 0.5 占 퐉 is formed by an ideal manufacturing process and when overlapping Respectively.

As can be understood from Fig. 5, the inclination of the light intensity distribution when the overlap (line) of 0.5 占 퐉 or 1.0 占 퐉 is formed is not substantially changed from the case of the ideal type (0 占 퐉) Is slightly larger when the inclination angle is maximum). In other words, in the formation of the overlapping (line) itself, there is no big problem of the transfer image, and rather, it is understood that the profile of the resist pattern is more advantageous as the etching mask (the inclination angle of the cross section of the resist pattern is large).

However, in spite of the inclination of the light intensity distribution as shown in Figs. 4 and 5, the inventors of the present invention have found out that the problem actually arises due to the alignment deviation.

That is, in the vicinity of the boundary between the first and second semitransparent portions in the photomask surface, a portion where the gap (slit) is formed (see (c) in FIG. 3) (C) and (e) of FIG. 3) are mixed on the same surface as a result of which the light-shielding film (line) is formed (see FIG. 3 (e) . This occurs as a sum of positional shifts that occur when the photomask is placed a plurality of times on the imaging device and those in which the coordinate displacements of the imaging device that occur at the plurality of imaging operations occur non-uniformly depending on the position.

In general, in a photomask product, after patterning, several kinds of inspections are performed to check the performance, and correction is performed depending on the inspection results. One of the tests is defect inspection. When a missing defect (a white defect) such as a pin hole or an extra defect (a black defect) such as a spot generated in each film remains in a photomask manufacturing process, a correct transfer image is formed I can not do it.

As the defect inspection, there is a method of detecting a pattern defect by observing the two patterns using a pattern defect inspection apparatus and comparing the transmittance (a method of detecting a pattern defect (a die -to-Die test) is the most efficient and highly accurate. That is, when the transmittances of the same pattern at different positions are compared and there is a portion where the difference exceeds the threshold value, the presence of a defect is indicated.

However, as described above, when a gap (slit) or an overlap (line), which is caused by an alignment shift in a plurality of photolithography processes, is mixed, when the existence of a defect is indicated for a pattern having the same shape at different portions . That is, even when the deviation from the optimum transmittance (design value) is within the allowable range, when the portion where the gap (slit) is generated is compared with the portion where the overlap (line) occurs, if the difference exceeds the threshold value There is.

As described above, these problems do not affect the operation of the final product, but a large number of pseudo defects are detected. When a large number of pseudo defects are detected, it is difficult to detect a real defect, and there is a risk that the production efficiency is largely lowered. Further, when the number of pseudo defects is detected as a defect by exceeding a normal defect occurrence probability, it is determined that the inspection is impossible and the process is stopped.

A photomask having a transfer pattern for manufacturing a more advanced device can not but complicate its configuration. In the photomask having such a complicated structure, even when a plurality of photolithography processes are applied, an excellent manufacturing method is desired so that the alignment displacement does not impair the precision irradiation process or the function of the final product.

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide a method of manufacturing a multi-gradation photomask capable of forming a high-precision transfer pattern, a photomask using the same, a pattern transfer method using the photomask, A method of manufacturing a flat panel display using a pattern transfer method is proposed.

Particularly, the present invention provides a method of manufacturing a multi-gradation photomask of 4 gradations or more by patterning a plurality of semitransparent films, without causing a decrease in production efficiency despite the positional deviation of each pattern due to the alignment deviation, And a precision of the final product can be obtained.

One embodiment of the method for manufacturing a multi-gradation photomask of the present invention for solving the above-mentioned problems is a method for manufacturing a multi-gradation photomask including a transfer pattern having a transferring portion, a light-shielding portion, a transferring pattern including a first semitransparent portion and a second semitransparent portion, A method of manufacturing a multi-gradation photomask, wherein the first semitransparent portion has a first semitransparent film formed on the transparent substrate, and the second semitransparent portion is formed on the transparent substrate differently from the first semi- And a second semi-light-transmitting film having an exposure light transmittance, wherein the first semitransparent section and the second semitransmissive section have adjacent portions, the method comprising the steps of: A step of preparing a photomask blank in which a film and a light-shielding film are laminated and a first resist film is further formed, a first resist film is formed on the first resist film, A first etching step of etching the light-shielding film and the first semi-light-transmitting film using the first resist pattern as a mask; and a second etching step of forming a second semi-light-transmitting film on the entire surface of the transparent substrate after the first etching step And forming a second resist film by performing a second drawing on the second resist film to form a second resist pattern and etching the second semitransparent film using the second resist pattern as a mask And a peripheral portion of the first semitransparent film and the second semitransparent film is formed at a boundary between the first semitransparent portion and the second semitransparent portion after the second etching by an overlap amount of a predetermined range The drawing data of the first drawing or the second drawing is formed so as to have overlapping.

Here, the exposure light transmittance of the first translucent portion and the second translucent portion may be either higher. The exposure light transmittance of the light transmitting portion and the light shielding portion can be a value having a certain width in a range applicable industrially as a light transmitting portion or a light shielding portion.

The formation of the imaging data (data) for the first imaging or the second imaging such that the peripheral portion of the first semitransparent film and the second semitransparent film overlap by the overlap amount of the predetermined range is performed only at the time of the first imaging And also includes forming the drawing data having the overlap only at the time of the second drawing and also forming the drawing data having the overlap at both of the first drawing and the second drawing .

The present embodiment also includes the case where another film is formed in addition to the light-shielding film, the first semitransparent film and the second semitransparent film. The first and second resist films may be either a positive resist or a negative resist.

As described above, between the first photolithography process and the second photolithography process, misalignment of the pattern caused by positioning with reference to the alignment mark and misalignment of the coordinates of the imaging device occur unevenly As the sum of the deviations caused by the alignment, alignment displacement occurs. By forming imaging data in which the first semi-light-transmitting film and the second semi-light-transmitting film are sized so as to overlap each other by a value corresponding to the maximum value of the alignment deviation, It is possible to make the peripheral portion of the film and the second semitransparent film overlap with each other by an overlap amount in a predetermined range.

Therefore, in the present embodiment, when manufacturing a multi-grayscale photomask having four gradations by patterning a plurality of semitransparent films, it is possible to solve the difficulty in production caused by the alignment shift, It is possible to provide a photomask manufacturing method which can obtain a photomask satisfying the specification.

Another embodiment of the method for producing a multi-gradation photomask of the present invention is characterized in that the predetermined range of the overlap amount is in a range larger than 0 and smaller than 1.5 mu m.

More preferably greater than 0 and less than 1.0 占 퐉.

Another embodiment of the method for manufacturing a multi-gradation photomask of the present invention is a method for manufacturing a multi-gradation photomask having a transfer pattern including a light-transmitting portion, a light-shielding portion, a first translucent portion, and a second translucent portion on a transparent substrate Wherein the first translucent portion is formed on the transparent substrate with a first translucent film, and the second translucent portion is formed on the transparent substrate with a second translucent light having a different exposure light transmittance from the first translucent film, And a second semitransparent portion and a second semitransparent portion, wherein the first semitransparent portion and the second semitransparent portion are adjacent to each other, wherein the first semitransparent film and the light shielding film are laminated on the transparent substrate, Preparing a photomask blank in which a resist film is further formed, performing a first drawing operation on the first resist film to form a first resist pattern, A first etching step of etching the light shielding film and the first semitransparent film using the jig pattern as a mask; a step of forming a second semitransparent film and a second resist film on the entire surface of the transparent substrate after the first etching step; And a second etching step of etching the second semi-light-transmitting film using the second resist pattern as a mask, wherein the second resist pattern is formed by performing a second drawing on the second resist film, (Edge) of the first semi-light-transmitting film and the second semi-light-transmitting film are spaced apart from each other by a predetermined distance in the boundary between the first semitransparent portion and the second semitransparent portion after the second etching, And the data of the second rendering is formed.

Also in this embodiment, the exposure light transmittance of the first translucent portion and the second translucent portion may be either higher. The exposure light transmittance of the light transmitting portion and the light shielding portion can be a value having a certain width in a range applicable industrially as a light transmitting portion or a light shielding portion.

The formation of the data for the first imaging or the second imaging such that the edges (end portions) of the first and second semitransparent films are spaced apart from each other by a predetermined distance is not limited to the imaging Forming the data includes forming the drawing data which is spaced only at the time of the second drawing and includes forming the drawing data which are spaced apart in both the first drawing and the second drawing.

Also in this embodiment, the case where another film is formed in addition to the light-shielding film, the first semitransparent film and the second semitransparent film is also included. The first and second resist films may be either positive resist or negative resist.

In the present embodiment, the imaging data for patterning the first and second semi-light-transmitting films are always sized by the value corresponding to the maximum value of the alignment shift, Can be spaced apart from each other by a predetermined distance.

As a result, as shown in Fig. 4, it is possible to manufacture a multi-gradation photomask which is always advantageous (a resist pattern having a large inclination angle of a cross section can be formed).

Also in this embodiment, it is possible to solve the production difficulty caused by the alignment deviation when patterning is performed on a plurality of semitransparent films to produce a 4-gradation or more multi-gradation photomask, It is possible to provide a photomask manufacturing method in which a satisfactory photomask is obtained.

Another embodiment of the method for manufacturing a multi-gradation photomask of the present invention is characterized in that the predetermined range of the spacing distance is in a range of larger than 0 and smaller than 1.5 mu m.

More preferably, it is larger than 0 and smaller than 1.0 탆.

One embodiment of the multi-gradation photomask of the present invention is a multi-gradation photomask provided with a transfer pattern including a transparent portion, a light-shielding portion, a first translucent portion and a second translucent portion on a transparent substrate, A second translucent film is formed on the transparent substrate, the second translucent film having an exposure light transmittance different from that of the first translucent film on the transparent substrate, wherein the translucent portion has a first translucent film formed on the transparent substrate, Wherein the first semitransparent portion and the second semitransparent portion are adjacent to each other, wherein in a boundary portion between the first semitransparent portion and the second semitransparent portion, And the periphery of the film and the second semi-light-transmitting film are formed with overlapping by an overlap amount in the range of 0.1 to 1.5 mu m.

Another embodiment of the multi-gradation photomask of the present invention is a multi-gradation photomask provided with a transfer pattern including a transparent portion, a light-shielding portion, a first translucent portion, and a second translucent portion on a transparent substrate, And the second translucent portion is formed on the transparent substrate with a second translucent film having an exposure light transmittance different from that of the first translucent film on the transparent substrate, wherein the translucent portion has a first translucent film formed on the transparent substrate Wherein the first semi-transmissive portion and the second semi-transmissive portion have adjacent portions, wherein in a boundary portion between the first semi-transmissive portion and the second semi-transmissive portion, And an edge (end) of the second semi-light-transmitting film are spaced apart from each other by a distance of 0.1 to 1.5 탆.

One embodiment of the pattern transfer method of the present invention is a method for transferring a pattern using the multi-gradation photomask manufactured by any one of the above-described manufacturing methods or the multi- Is transferred onto the transfer target body.

One embodiment of the method for manufacturing a flat panel display of the present invention is characterized by using the above-described pattern transfer method.

According to the present invention, when a multi-grayscale photomask of 4 gradations or more is formed by patterning a plurality of semitransparent films, the production difficulty due to the alignment deviation is eliminated, and a multi-gradation photomask satisfying the specification It is possible to provide a method of manufacturing a photomask, and a photomask, a method of transferring a pattern, and a method of manufacturing a flat panel display using the photomask.

1 is a schematic view showing a conventional method of manufacturing a photomask.
2 is a schematic view showing a conventional method of manufacturing a four-tone photomask.
Fig. 3 is a schematic view showing a transfer pattern formed by alignment displacement in the manufacturing method of Fig. 2. Fig.
Fig. 4 is a graph showing a light intensity distribution on a transferred body when a boundary is formed as designed and a gap (slit) is formed at a boundary; Fig.
5 is a graph showing the light intensity distribution on the transferred body when the boundary is formed as designed and when the boundary (line) is formed at the boundary.
Fig. 6 is a schematic diagram showing a first embodiment of the method for manufacturing a photomask of the present invention, which shows a case where the overlapping (line) is always formed.
Fig. 7 is a schematic view showing a second embodiment of the method (imaging method) of the photomask of the present invention, which shows a case where a gap (slit) is always formed.

≪ Description of First Embodiment of Present Invention >

In the first embodiment of the method for producing a multi-gradation photomask of the present invention, the same manufacturing process as that of Fig. 2 is performed, but the first drawing corresponding to Fig. 2 (b) In that the drawing data of the first drawing or the second drawing is formed so that the periphery of the first semi-light-transmitting film and the second semitransparent film overlaps by the overlap amount of the predetermined range in the second drawing corresponding to the second drawing.

More specifically, first, a photomask blank is prepared by laminating a first semi-light-transmitting film and a light-blocking film on a transparent substrate and further forming a first resist film (corresponding to FIG. 2A). Then, the first resist film is subjected to a first drawing process and then developed to form a first resist pattern (corresponding to FIG. 2 (b)). Here, in the present embodiment, in the first drawing, the drawing data is not processed. In the second drawing of the subsequent step, the peripheral portions of the first and second semi-light-transmitting films are overlapped by a predetermined overlap amount So as to form the sketched data. An embodiment of the present invention relating to the second rendering will be described later in detail with reference to Fig.

However, instead of the second imaging operation, in the first imaging operation, imaging data may be formed in which the first semi-light-transmitting film and the second semi-light-transmitting film are sized so as to overlap with each other. In both of the first imaging data and the second imaging data, The imaging data may be formed by sizing the first semi-light-transmitting film and the second semi-

Next, a first etching step for etching the light-shielding film and the first semi-light-transmitting film using the first resist pattern as a mask (corresponding to (c) and (d) in FIG. 2) (e)). Then, a second semi-light-transmitting film and a second resist film are formed on the entire surface of the transparent substrate after the first etching step (corresponding to (f) and (g) in FIG. 2).

Then, the second resist film is subjected to second drawing to form a second resist pattern (corresponding to (h) in FIG. 2).

Here, referring to Fig. 6, in the second drawing, the drawing data of the first drawing or the second drawing is formed so that the periphery of the first semitransparent film and the second semitransparent film overlaps by the overlap amount of the predetermined range The process will be described in detail. As described above, between the first photolithography process and the second photolithography process, misalignment of the pattern caused by positioning with reference to the alignment mark and misalignment of the coordinates of the imaging device occur unevenly As the sum of the deviations caused by the alignment, alignment displacement occurs.

6 (a) and 6 (b) show a case in which drawing is shifted to the left by alignment displacement, and FIGS. 6 (c) and 6 (d) show a case in which drawing is shifted to the right by alignment displacement .

First, a case in which the drawing is shifted to the left by the alignment deviation will be described with reference to Figs. 6 (a) and 6 (b). 6 (a) corresponding to the second imaging / developing step of FIG. 2 (h), in the boundary portion between the first semi-light-transmitting film and the second semi-light-transmitting film, although the imaging is shifted to the left, (Edge) portion of the second resist pattern after drawing 2 is superimposed on the first semitransparent film. This is because in the second imaging, the right end portion of the second resist pattern is extended to the right side (the direction in which the first semi-light-transmitting film and the second semi-light-transmitting film overlap) by a predetermined value corresponding to the maximum value of the alignment deviation Can be realized by forming data. In other words, the width of the resist is formed to be larger by a predetermined dimension corresponding to the maximum value of the alignment displacement.

Then, the second semi-light-transmitting film is etched and the light-transmitting portion is formed using the second resist pattern as a mask, and the second semi-light-transmitting film and the light-blocking film are etched to expose the first semi-light-transmitting film ((i) , And then the second resist pattern is peeled off to complete the 4-gradation photomask as shown in Fig. 6 (b) (corresponding to Fig. 2 (j)). As shown in Fig. 6 (b), the periphery of the first semi-light-transmitting film and the second semitransparent film can be overlapped with each other by a predetermined amount of overlap even though the drawing shifts to the left.

Next, a case in which drawing is shifted to the right by alignment displacement will be described using Figs. 6 (c) and 6 (d). 6 (c) corresponding to the second imaging / developing step of FIG. 2 (h), the imaging is shifted to the right, and at the boundary between the first and second semitransparent films, And the right end portion of the second resist pattern after the second resist pattern overlap with the first semitransparent film. The overlapped amount of the first semi-light-transmitting film and the second semi-light-transmitting film becomes larger as compared with the case of shifting to the left side in Fig. 6 (a).

Then, the second semi-light-transmitting film is etched using the second resist pattern as a mask to form a light-transmitting portion, and the second semitranslucent film and the light-shielding film are etched to expose the first semi-light-transmitting film ((i) Then, the second resist pattern is peeled off to complete the 4-gradation photomask as shown in FIG. 6 (d) (corresponding to FIG. 2 (j)). As shown in Fig. 6 (d), the periphery of the first semi-light-transmitting film and the second semi-light-transmitting film have overlapping by the overlap amount of the predetermined range.

In this embodiment, in the second drawing, the edge (edge) of the second resist pattern on the boundary side is shifted to the right side (the direction in which the first and second semitransparent films overlap each other) by the value corresponding to the maximum value of the alignment deviation , Even when the imaging is shifted to the left or the shift to the right due to the alignment deviation, the peripheral portions of the first and second semi-light-transmitting films always overlap with each other in the predetermined range As shown in FIG.

On the other hand, in the conventional imaging data, as shown by the dotted line, when the actual imaging shifts to the left, the first semi-light-transmitting film and the second semi-light-transmitting film are separated from each other, Film and the second semitranslucent film overlap. That is, due to the alignment deviation, a pattern overlapping with a pattern in which the first semitransparent film and the second semitransparent film are spaced apart is mixed.

As described above, in the present embodiment, when patterning is performed on a plurality of semi-light-transmitting films to produce a multi-gradation photomask of 4 gradations or more, the difficulties in production caused by the alignment shift are solved, And the precision of the final product can be obtained. Further, in the present embodiment, since the number of times of rendering is indispensable is two, excellent productivity is obtained.

When the overlap width of the first and second semitransparent films is A, it is preferable that 0 < A &amp;le; 1.5 mu m. More preferably, 0.1 &lt; A &amp;le; 1.0 mu m.

In the present embodiment, by setting the predetermined range of the overlap amount within the above range, it is possible to provide a multi-gradation photomask satisfying the specification without affecting the design pattern.

In order to realize this, as described above, at least the width of either the first resist pattern or the second resist pattern at the boundary between the first semi-light-transmitting film and the second semitranslucent film corresponds to the maximum value of the alignment deviation The width of the first resist pattern and the width of the second resist pattern can be increased by a predetermined dimension or by increasing the width of both the first resist pattern and the second resist pattern by a predetermined dimension in total.

When the exposure light transmittance of the first semi-light-transmitting film is T1 and the exposure light transmittance of the second semitransparent film is T2, when T1 > T2, the second resist pattern is irradiated from the second semi- It is preferable to form the drawing data of the second drawing so as to be formed by the predetermined width to the first translucent portion side.

Conversely, in the case of T1 < T2, it is preferable to form the drawing data of the first drawing so that the first resist pattern is formed at the boundary, from the first translucent portion side to the second translucent portion side, Do.

Further, by the optical simulation, the overlapping width of the semitransparent film, the width of the gap, or the formation position thereof can form optimum drawing data. In addition, both of the drawing data of the first drawing and the drawing of the second drawing may be corrected, and the predetermined overlapping width may be formed as the sum.

In the first embodiment, the positive resist from which the exposed portion is removed is used. However, the present invention is not limited to this, and a negative resist in which the exposed portion remains can be used and can be determined according to the use.

&Lt; Description of the second embodiment of the present invention &

Next, a second embodiment of a method for manufacturing a multi-gradation photomask of the present invention will be described. In the present embodiment, the same manufacturing process as in Fig. 2 is performed. However, in the first drawing corresponding to Fig. 2 (b) or the second drawing corresponding to Fig. 2 (h) (Edge) of the first semi-light-transmitting film and the second semi-light-transmitting film are spaced apart from each other by a separation distance within a predetermined range.

More specifically, first, a photomask blank is prepared by laminating a first semi-light-transmitting film and a light-blocking film on a transparent substrate and further forming a first resist film (corresponding to FIG. 2A). Then, the first resist film is subjected to a first drawing process and then developed to form a first resist pattern (corresponding to FIG. 2 (b)). In the first drawing, the drawing data is not processed. In the second drawing of the subsequent step, the end portions (edges) of the first and second semi-light-transmitting films are spaced apart from each other by a predetermined distance, Thereby forming the drawing data. An embodiment of the present invention relating to the second rendering will be described later in detail with reference to Fig.

However, instead of the second imaging operation, in the first imaging operation, imaging data may be formed so as to separate the first translucent film and the second translucent film. In both of the first imaging data and the second imaging data, The imaging data may be formed so that the semitransparent film and the second semitransparent film are spaced apart from each other.

Next, a first etching step for etching the light-shielding film and the first semi-light-transmitting film using the first resist pattern as a mask (corresponding to (c) and (d) in FIG. 2) (e)). Then, a second semi-light-transmitting film and a second resist film are formed on the entire surface of the transparent substrate after the first etching step (corresponding to (f) and (g) in FIG. 2).

Then, the second resist film is subjected to second drawing to form a second resist pattern (corresponding to (h) in FIG. 2).

Here, referring to Fig. 7, in the second imaging, the imaging data of the first imaging or the second imaging is set so that the end portions (edges) of the first and second semitransparent films are spaced apart from each other by a predetermined distance The forming process will be described in detail.

7A and 7B show a case in which the drawing is shifted to the left by the alignment deviation and FIGS. 7C and 7D show the case where the drawing is shifted to the right by the alignment deviation .

First, a case where the drawing is shifted to the left by the alignment deviation will be described using Figs. 7 (a) and 7 (b). In FIG. 7A corresponding to the second imaging / developing step of FIG. 2H, the imaging is shifted to the left, and in the boundary portion between the first and second semi-light-transmitting films, And the right end (edge) of the second resist pattern is separated from the first semitransparent film. This is because in the second imaging, the right side end portion of the second resist pattern is drawn backward (the direction in which the first semi-light-transmitting film and the second semi-light-transmitting film are separated) by a predetermined value corresponding to the maximum value of the alignment shift, Can be realized by forming data. In other words, the width of the resist is formed to be smaller by a predetermined dimension corresponding to the maximum value of the alignment displacement.

Then, the second semi-light-transmitting film is etched using the second resist pattern as a mask to form a light-transmitting portion, and the second semitranslucent film and the light-shielding film are etched to expose the first semi-light-transmitting film ((i) Then, the second resist pattern is peeled off to complete the 4-gradation photomask as shown in FIG. 7 (b) (corresponding to FIG. 2 (j)). As shown in the drawing, the end portions (edges) of the first and second semi-light-transmitting films can be spaced apart from each other by a predetermined distance.

Next, a case where the drawing is shifted to the right by the alignment deviation will be described using Figs. 7C and 7D. 7 (c) corresponding to the second imaging / developing step of FIG. 2 (h), in the boundary portion between the first and second semitransparent films, although the imaging is shifted to the right, (Edge) of the second resist pattern after drawing 2 is separated from the first semitransparent film.

In this embodiment, in the second drawing, the edge (edge) of the second resist pattern on the boundary side is shifted to the left side (the first semi-light-transmitting film and the second semi-light-transmitting film are spaced apart by a value corresponding to the maximum value of the alignment deviation In the case where the imaging shift is shifted to the left by the alignment displacement, even when shifting to the right side, the first semi-light-transmitting portion and the second semi- (Edges) of the first semi-light-transmitting film and the second semi-light-transmitting film may be spaced apart from each other by a predetermined distance.

On the other hand, in the conventional imaging data, as shown by the dotted line, when the imaging is shifted to the left, the first semi-light-transmitting film and the second semi-light-transmitting film are separated from each other, The second semitranslucent film overlaps. That is, due to the alignment deviation, a pattern overlapping with a pattern in which the first semitransparent film and the second semitransparent film are spaced apart is mixed.

As described above, also in this embodiment, when manufacturing a multi-grayscale photomask of 4 gradations or more by patterning a plurality of semitransparent films, it is possible to eliminate production difficulties due to alignment shifts, And the precision of the final product can be obtained. Also in this embodiment, since the number of times of painting is indispensable is twice, excellent productivity is obtained.

When the separation distance between the first and second semi-light-transmitting films is B, 0 <B? 1.5 占 퐉 is preferable. More preferably 0.1 < B &amp;le; 1.0 mu m.

In the present embodiment, by setting the range of the separation distance to the above-mentioned range, it is possible to provide a multi-gradation photomask satisfying the specification without affecting the design pattern.

In order to realize this, as described above, at least one of the widths of at least the first resist pattern or the second resist pattern at the boundary between the first semitransparent film and the second semitransparent film is set to a value corresponding to the maximum value of the alignment deviation The width of the first resist pattern and the width of the second resist pattern can be reduced by a predetermined spacing distance or by making the widths of both the first resist pattern and the second resist pattern small so as to be a predetermined distance in total.

(Edge) of the first resist pattern is retreated toward the first semi-transmissive portion formation region, or the end portion (edge) of the second resist pattern is retracted toward the second semi-transmissive portion formation region side Or the end portions (edges) of the first and second resist patterns are retracted, respectively.

For example, if the exposure light transmittance of the first semi-light-transmitting film is T1 and the exposure light transmittance of the second semitransparent film is T2, and if T1 > T2, ) Can be retreated at the boundary portion by a predetermined distance (i.e., the width of the first resist pattern is made smaller than the abnormal state). This can be done by correcting the imaging data used for the first imaging.

Conversely, in the case of T1 < T2, the end (edge) of the second resist pattern is moved backward by the predetermined distance in the boundary portion (that is, the width of the second resist pattern is set to It can be made smaller than the abnormal state). This can be done by correcting the imaging data used for the second imaging. It goes without saying that both of the drawing data of the first drawing operation and the drawing operation data of the second drawing operation may be corrected and the predetermined spacing distance may be formed as the sum.

In the second embodiment, the positive resist from which the exposed portion is removed is used. However, the present invention is not limited to this, and a negative resist in which the exposed portion remains can be used and can be determined according to the use.

In any of the above-described first and second embodiments, the following preferred embodiments can be employed. The mutual etching selectivity between the second semitranslucent film and the light-shielding film is not required, and it is preferable that both are etchable with a common etchant. On the other hand, the first semitransparent film and the light-shielding film need to have etching selectivity (the light shielding film or the first semitransparent film has resistance to the etchant of the second semitransparent film).

Specific examples of the material of the semitransparent film include Cr compounds (oxides, nitrides, carbides, oxides, oxynitrides and carbides of Cr), Si compounds (SiO ₂ , SOG), metal silicide compounds (TaSi, MoSi, WSi, , Oxynitride, etc.) can be used.

As the light shielding film material, Ta, W, or a compound thereof (including the above metal silicide) and the like may be used in addition to Cr or a Cr compound (an oxide, a nitride, a carbide, a nitride of an oxynitride,

In consideration of etching selectivity, it is preferable that the first semi-light-transmitting film is made of MoSi-based, Si-based, second semi-light-transmitting film and light-shielding film are Cr-based.

It is preferable that the light shielding film does not substantially transmit the exposure light (optical degree OD is 3 or more) in a state of being laminated with the first and second semitransparent film. However, depending on the use of the photomask, (For example, transmittance &amp;le; 20%). In either case, the exposure light transmittance of each of T1 and T2 is determined in accordance with the use of the multi-gradation photomask. It can also be adjusted through the optical simulation.

Preferably, when one of the first semi-light-transmitting film and the second semi-light-transmitting film has an exposure light transmittance of 40 to 80%, the other has an exposure light transmittance of 5 to 50%. Further, it is preferable that the difference in the exposure light transmittance of both is 30% or more.

Further, in both of the first and second semi-light-transmitting films, the amount of phase shift relative to the exposure light is 90 DEG or less, preferably 60 DEG or less. In this case, the phase shift amount with respect to the representative wavelength (e.g., i-line) of the exposure light is preferable, but it is preferable that the phase shift amount range is the above-described range of the amount of all of i line to g line.

&Lt; Explanation of still another effect of the present invention &

In addition, the manufacturing method of the first and second embodiments includes a defect inspection process using a die-to-die inspection method for detecting a pattern defect by comparing transmittances of two portions, The effect of the invention is remarkably obtained.

6 and 7 show the main part of the method for manufacturing the multi-gradation photomask of the present invention, as described above. Here, the drawing data obtained by performing correction on the drawing data based on the design value is used in the process of forming the drawing data used for the second drawing for forming the second resist pattern.

6A and 6C, the first embodiment is applied to a case where the drawing data of the second drawing for forming the second resist pattern is corrected (solid line) with respect to the design value Of the resist pattern.

Then, using the resist pattern as a mask, the second semi-light-transmitting film and the light-shielding film are etched, and the obtained multi-gradation photo mask is shown in (b) and (d) of FIG. Even if the second resist pattern shifts to the left or to the right with respect to the first resist pattern, in the adjacent boundary portion between the first semitransparent section and the second semitransparent section, the overlapping of the first and second semitransparent films (A light-shielding film is also laminated) is formed. That is, the first and second semitransparent films do not form a gap due to the alignment deviation at the boundary. Therefore, no problem occurs in the above-described die-to-die inspection.

In FIGS. 7A and 7C, the second embodiment is applied to correct the drawing data of the second drawing for forming the second resist pattern (solid line) with respect to the design value (dotted line) The resist pattern to be formed is shown.

Then, using the resist pattern as a mask, the second semi-light-transmitting film and the light-shielding film are etched, and the obtained multi-gradation photo mask is shown in (b) and (d) of FIG. The first and second semitransparent portions are spaced apart from each other at the boundary portion between the first semitransparent portion and the second semitransparent portion even when the second resist pattern and the first resist pattern are shifted to the right or left, A gap is formed. That is, the first and second semi-light-transmitting films do not form overlapping due to the alignment deviation at the boundary. Therefore, in this case also, no problem occurs in the above-described die-to-die inspection.

&Lt; Description of photomask of the present invention >

The present invention includes a multi-gradation photomask obtained by the above-described first embodiment. Specifically, a multi-gradation photomask having a transfer pattern including a light-transmitting portion, a light-shielding portion, a first semitransparent portion, and a second semitransparent portion is formed on a transparent substrate. The first semi- And the second translucent portion is formed on the transparent substrate with a second translucent film having an exposure light transmittance different from that of the first translucent film, and the first translucent portion and the second translucent portion are adjacent to each other In the multi-gradation photomask having the portion where the first semi-light-transmitting portion and the second semi-light-transmitting portion are adjacent to each other, the peripheral portion of the first semi-light-transmitting film and the second semi- Is a multi-gradation photomask formed with overlapping.

In this case, at the boundary between the first semitransparent portion and the second semitransparent portion, no separation of 0.1 to 1.5 mu m due to the alignment deviation between the first semitransparent film and the second semitransparent film occurred.

This multi-gradation photomask is formed such that the peripheral portion of the first semi-light-transmitting film and the second semi-light-transmitting film overlap with each other by an overlap amount in the range of 0.1 to 1.5 占 퐉, , The productivity is excellent, and as shown in Fig. 5, the light transmission profile is also excellent.

The present invention also includes a multi-gradation photomask obtained by the above-described second embodiment. Specifically, a multi-gradation photomask having a transfer pattern including a light-transmitting portion, a light-shielding portion, a first semitransparent portion, and a second semitransparent portion is formed on a transparent substrate. The first semi- And the second translucent portion is formed on the transparent substrate with a second translucent film having an exposure light transmittance different from that of the first translucent film, and the first translucent portion and the second translucent portion are adjacent to each other (Edge) of the first semi-light-transmitting film and the second semitransparent film is in the range of 0.1 to 1.5 占 퐉 in the boundary portion between the first semi- And is spaced apart from each other by a spacing distance.

In this case, at the boundary between the first semitransparent portion and the second semitransparent portion, no overlapping of 0.1 to 1.5 mu m due to the alignment deviation between the first semitransparent film and the second semitransparent film occurred.

In the multi-gradation photo mask, the gap portion and the overlap portion are not mixed, and the end portions (edges) of the first and second semi-light-transmitting films are spaced apart from each other by a distance of 0.1 to 1.5 탆 , So that the productivity is excellent and, as shown in Fig. 4, the light transmission profile is also excellent

&Lt; Description of pattern transfer method using photomask of the present invention >

The present invention also includes a pattern transfer method for transferring a transfer pattern to a transfer target body using an exposure apparatus using the photomask manufactured by the above manufacturing method. It also includes a flat panel display (FPD) manufacturing method using this pattern transfer method.

The exposure apparatus used in the transfer can be a standard LCD (liquid crystal display) exposure apparatus that applies a mirror projection or a lens scanner to perform transfer by the same exposure. In this case, for example, the numerical aperture NA may be in the range of 0.06 to 0.10, and σ 0.5 to 1.0. Such an exposure apparatus generally has a resolution limit of about 3 mu m.

Of course, the present invention can also be applied to the case of transfer using a wider range of exposure apparatus. For example, the NA may be in the range of 0.06 to 0.14, or 0.06 to 0.15. Needs also arise in high-resolution exposure apparatuses where the NA exceeds 0.08, and the present invention can be applied to these.

Such an exposure apparatus includes i-line, h-line, and g-line as a light source, and irradiation light including both of them is used (also referred to as 'broad light' hereinafter) because it is a light source broadened to a single light source. In this case (or during optical simulation), one of i-line, h-line, and g-line may be used as the representative wavelength in order to specify the transmittance and the amount of phase shift. In the simulation, these intensity ratios may be set to 1: 1: 1 for the sake of simplicity, or a ratio taking the intensity ratio of the actual exposure apparatus into consideration may be used.

The resist to be used on the transferred body may be positive or negative, and may be determined according to the use.

The application of the multi-gradation photomask of the present invention is not particularly limited. For example, it is advantageous for manufacturing a TFT (thin film transistor) of a flat panel display (FPD), for manufacturing a photo spacer of a color filter (CF), and the like.

As the transparent substrate used in the present invention, a quartz glass substrate having its surface polished is used. The size is not particularly limited and is suitably selected according to a substrate (for example, a substrate for a flat panel display) to be exposed using the mask. For example, a rectangular substrate 300 mm or more on one side is used.

Any known etchant used in each etching process may be used. As the Cr-based light-shielding film or semi-light-transmitting film, an etching solution containing ceric ammonium nitrate, which is known as an etchant for chromium, may be used. Dry etching using a chlorine-based gas may also be applied.

As the MoSi-based film, an etching solution in which an oxidizing agent such as hydrogen peroxide, nitric acid, or sulfuric acid is added to a fluorine compound such as hydrofluoric acid, hydrofluoric acid, or ammonium hydrogen fluoride can be used. Alternatively, a fluorine-based etching gas may be used.

Preferably, in the etching step, it is convenient to apply wet etching in all cases.

As described above, by using the photomask of the present invention, it is possible to realize a pattern transfer method capable of forming a highly accurate circuit pattern and obtaining a high final product precision. By applying this pattern transfer method, A flat panel display can be manufactured.

<Description of Other Embodiments of the Present Invention>

In the description of the above embodiments, the first and second semi-light-transmitting films and the light-shielding film are formed, but a semi-light-transmitting film may be used instead of the light-shielding film. Therefore, the light shielding film can be replaced with the third semitranslucent film, and the first through third semitranslucent films can take an arbitrary exposure light transmittance.

Further, the present invention is not limited to the above-described embodiments, but includes various other embodiments.

10: Gray-tone mask (photomask)
13:
14:
15A: a first translucent portion
15B: a second translucent portion
16: Transparent substrate
17A: First semi-transparent film
17B: Second semi-transparent film
18:
20: Photomask blank
21: First resist pattern
24: Photomask blank
25: Second resist pattern

Claims (10)

A method of manufacturing a multi-gradation photomask comprising a transparent substrate and a transfer pattern including a light-transmitting portion, a light-shielding portion, a first translucent portion, and a second translucent portion, wherein the first translucent portion comprises: And a second translucent film is formed on the transparent substrate, the second translucent film being formed on the transparent substrate, the second translucent film having an exposure light transmittance different from that of the first translucent film, 2 A method of manufacturing a multi-gradation photomask having a semi-transparent portion and an adjacent portion,
A step of preparing a photomask blank in which a first semi-light-transmitting film and a light-shielding film are laminated on the transparent substrate and further a first resist film is formed;
A step of forming a first resist pattern by performing a first drawing on the first resist film,
A first etching step of etching the light-shielding film and the first semitransparent film using the first resist pattern as a mask,
A step of forming a second translucent film and a second resist film on the entire surface of the transparent substrate after the first etching step,
A step of forming a second resist pattern by performing a second drawing on the second resist film,
And a second etching step of etching the second semitransparent film using the second resist pattern as a mask,
And the peripheral portion of the first semi-light-transmitting film and the second semi-light-transmitting film overlap each other at a boundary between the first semitransparent portion and the second semitransparent portion after the second etching, And forming the drawing data of the first drawing or the second drawing. The method according to claim 1,
Wherein the predetermined range of the overlap amount is larger than 0 and smaller than 1.5 占 퐉. A method of manufacturing a multi-gradation photomask comprising a transparent substrate and a transfer pattern including a light-transmitting portion, a light-shielding portion, a first translucent portion, and a second translucent portion, wherein the first translucent portion comprises: And a second translucent film is formed on the transparent substrate, the second translucent film being formed on the transparent substrate, the second translucent film having an exposure light transmittance different from that of the first translucent film, 2 A method of manufacturing a multi-gradation photomask having a semi-transparent portion and an adjacent portion,
A step of preparing a photomask blank in which a first semi-light-transmitting film and a light-shielding film are laminated on the transparent substrate and further a first resist film is formed;
A step of forming a first resist pattern by performing a first drawing on the first resist film,
A first etching step of etching the light-shielding film and the first semitransparent film using the first resist pattern as a mask,
A step of forming a second translucent film and a second resist film on the entire surface of the transparent substrate after the first etching step,
A step of forming a second resist pattern by performing a second drawing on the second resist film,
And a second etching step of etching the second semitransparent film using the second resist pattern as a mask,
And the second semi-light-transmitting film and the second semitransparent film are spaced apart from each other by a predetermined distance in the boundary between the first semitransparent portion and the second semitransparent portion after the second etching, And forming the data of the second imaging. The method of claim 3,
Wherein the predetermined range of the spacing distance is larger than 0 and smaller than 1.5 占 퐉. As a pattern transfer method,
A multi-gradation photomask manufactured by the manufacturing method according to any one of claims 1 to 4 is prepared,
Wherein the transfer pattern provided by the multi-gradation photomask is transferred to a transfer target body by an exposure apparatus. A method for manufacturing a multi-gradation photomask, comprising the steps of: preparing a multi-gradation photomask manufactured by the manufacturing method according to any one of claims 1 to 4;
And transferring the transfer pattern provided by the multi-gradation photo mask to an object to be transferred by the exposure apparatus. A multi-gradation photomask having a transfer pattern including a transparent portion, a light-shielding portion, a first translucent portion and a second translucent portion on a transparent substrate,
Wherein the first translucent portion has a first translucent film formed on the transparent substrate,
Wherein the second translucent portion is formed on the transparent substrate with a second translucent film having an exposure light transmittance different from that of the first translucent film,
Wherein the first translucent portion and the second translucent portion have adjacent portions,
And the peripheral portion of the first semi-light-transmitting film and the second semi-light-transmitting film is formed so as to have an overlapping amount in the range of 0.1 to 1.5 탆 in the boundary portion between the first translucent portion and the second translucent portion. A multi-tone photomask. A multi-gradation photomask having a transfer pattern including a transparent portion, a light-shielding portion, a first translucent portion and a second translucent portion on a transparent substrate,
Wherein the first translucent portion has a first translucent film formed on the transparent substrate,
Wherein the second translucent portion is formed on the transparent substrate with a second translucent film having an exposure light transmittance different from that of the first translucent film,
Wherein the first translucent portion and the second translucent portion have adjacent portions,
And an edge of the first semi-light-transmitting film and a second semi-light-transmitting film are spaced apart from each other by a distance in the range of 0.1 to 1.5 탆 at a boundary portion between the first and second semi- Multi-tone photomask. As a pattern transfer method,
A method for manufacturing a multi-gradation photomask, comprising the steps of: preparing the multi-gradation photomask according to claim 7 or 8;
And transferring the transfer pattern provided by the multi-gradation photo mask to an object to be transferred by an exposure apparatus. A method of manufacturing a flat panel display,
A method for manufacturing a multi-gradation photomask, comprising the steps of: preparing the multi-gradation photomask according to claim 7 or 8;
And transferring the transfer pattern provided by the multi-gradation photo mask to an object to be transferred by the exposure apparatus.

Images