KR101216242B1 - Method for fabricating photo mask using slit type halftone pattern and photo mask fabricated using thereof - Google Patents

Abstract

The present invention relates to a method of manufacturing a photo mask using a slit halftone pattern, and a photo mask using the same, including a plurality of light blocking patterns formed on an upper portion of a transparent substrate and a light transmitting area defined by the plurality of light blocking patterns. A method of manufacturing a mask, wherein a halftone pattern having a slit shape is formed on at least one of the sidewalls of the plurality of light blocking patterns facing each other, wherein the light blocking pattern is a TFT channel (Thin Film Transistor). A light blocking pattern defining a source electrode or a drain electrode defining a source electrode of a channel), and a halftone pad layer may be further formed on an upper surface of the light blocking pattern on which the halftone pattern is formed, and the line width of the halftone pattern is It relates to an invention characterized in that formed in the thickness of 10 to 80% of the light shielding pattern line width.

Description

METHODS FOR FABRICATING PHOTO MASK USING SLIT TYPE HALFTONE PATTERN AND PHOTO MASK FABRICATED USING THEREOF}

The present invention relates to a method of manufacturing a photo mask using a slit halftone pattern and a photo mask manufactured using the same. The present invention relates to a technique for solving a problem in which a short channel problem or an open / short margin is reduced.

Generally, when manufacturing a semiconductor device, an electronic device, a photoelectric device, a magnetic device, a display device, a microelectromechanical device, etc., a process of forming a fine pattern on a substrate is inevitably performed.

There are many methods for forming a fine pattern on a substrate, but a representative method is a photo lithography method for forming a fine pattern using light.

A method of forming a fine pattern on a substrate using the photolithography method described above is as follows.

First, a polymer material (eg, photoresist, etc.) having a reactivity to light is applied onto a substrate on which a material to be patterned is laminated (or deposited). Next, light is transmitted through the reticle designed in an arbitrary pattern of interest to expose the polymer material.

After exposure, the photomask having the target pattern is formed on the material to be patterned by removing the polymer material exposed through the developing process.

After forming the photo mask, an etching process using the formed photo mask is performed to pattern the material stacked on the substrate in a desired pattern.

These photo masks are binary masks that are patterned by simply transmitting and blocking light, and phases of neighboring patterns in which light is transmitted have a 180-degree difference to enhance resolution due to destructive interference. Phase Shifting Mask (PSM).

In addition, such a phase inversion mask includes both a light shielding film and a phase inversion film, and consists of an alternative phase inversion mask and a phase inversion layer having a transmittance of 100% of a phase inversion region and a halftone having a transmittance of 5 to 8%. Tone: HT) phase reversal mask.

However, in such a mask, in the region where the light shielding pattern is dense, such as a TFT film region, an intensity profile exposed to the wafer is formed asymmetrically, and this asymmetry is caused by the slope of the photoresist film. (Slope) is formed asymmetrically.

In addition, due to the asymmetry of the photoresist slope, a problem may occur in that electrode patterns are not normally formed after an etching process.

In particular, short channel problems or open / short margins may be reduced because the gap between the source and drain electrodes formed in the TFT channel region is not secured by the designed interval. have.

1 is a plan view showing a TFT channel region of a photomask according to the prior art.

Referring to FIG. 1, a light blocking pattern 120 defining a source electrode and a light blocking pattern 130 defining a drain electrode are provided on the mask substrate 100. In this case, in the case of the TFT channel, the light blocking pattern 120 defining the source electrode surrounds the light blocking pattern 130 defining the drain electrode, and the open / short margin is formed at the corner portion 140 indicated by the dotted line. The problem of decreasing margin frequently occurs.

In order to solve this problem, efforts have been made to secure open / short margins by adjusting the CD (critical dimension) of the photomask design process, but the short channel problem is still caused by the slight CD deviation. There is.

An object of the present invention is to solve a short channel problem or an open / short margin reduction problem caused by a narrow gap between a source electrode and a drain electrode, such as a TFT channel region. It is to provide a method of forming a slit-shaped halftone pattern on the sidewall of the light shielding pattern.

In addition, another object of the present invention is to provide a photomask having a structure including a slit halftone pattern formed on at least one of the sidewalls facing each other among each of the light blocking patterns.

A photomask manufacturing method according to an embodiment of the present invention for achieving the above object is to manufacture a photomask including a plurality of light shielding patterns formed on the transparent substrate and a light transmitting region defined by the plurality of light shielding patterns. The method may include forming a halftone pattern having a slit shape on at least one of the sidewalls facing each other among the sidewalls of the plurality of light blocking patterns.

The halftone pad layer may be further formed on an upper surface of the light blocking pattern on which the halftone pattern is formed, and the line width of the halftone pattern is 10 to 80% of the line width of the light blocking pattern. The light shielding pattern may be a light shielding pattern defining a source electrode of a TFT film (Thin Film Transistor Channel) or a light shielding pattern defining a drain electrode.

In addition, the transparent substrate is characterized in that the quartz (Quartz) substrate, the light shielding pattern is characterized in that the chrome pattern.

In addition, the method for manufacturing the photomask according to another embodiment of the present invention to form a light shielding layer on the entire transparent substrate, forming a first photosensitive film on the light shielding layer, Exposing and developing a first photosensitive film to form a first photosensitive pattern defining a source electrode and a drain electrode; and etching the light blocking layer using the first photosensitive pattern as a mask to define a first light blocking pattern And forming a second light blocking pattern defining a drain electrode, removing the first photosensitive pattern, and forming a halftone pad layer on an entire surface of the transparent substrate including the first light blocking pattern and the second light blocking pattern. Forming a second photoresist film on the halftone pad layer; and exposing and developing the second photoresist film to form the first light blocking pattern and the second difference. Forming a second photosensitive pattern corresponding to the light pattern, wherein a portion of the second photosensitive pattern corresponding to at least one of the sidewalls facing each other among the sidewalls of the first and second light blocking patterns Forming the expanded shape, etching the halftone pad layer or the halftone pad layer and the first light blocking pattern using the second photosensitive pattern as a mask, and removing the second photosensitive pattern. It is characterized by including.

In addition, the method for manufacturing the photomask according to another embodiment of the present invention further comprises forming a first halftone pad layer on the entire surface of the transparent substrate, and shielding the light on the first halftone pad layer. Forming a layer, forming a first photoresist film on the light shielding layer, exposing and developing the first photoresist film, and forming a first photoresist pattern defining a source electrode and a drain electrode; Etching the light blocking layer and the first halftone pad layer using a photosensitive pattern as a mask to form a first light blocking pattern defining a source electrode and a second light blocking pattern defining a drain electrode; Removing a pattern, forming a second halftone pad layer on an entire surface of the transparent substrate including the first light blocking pattern and the second light blocking pattern, and the second halftone pad layer Forming a second photoresist layer on the second photoresist layer; and forming a second photoresist pattern corresponding to the first light shielding pattern and the second light shielding pattern by exposing and developing the second photoresist film. Forming a portion of the second photosensitive pattern corresponding to at least one of the sidewalls of the second light blocking pattern facing each other such that a portion extends a predetermined region, and using the second photosensitive pattern as a mask And etching the halftone pad layer or the second halftone pad layer and the first light blocking pattern, and removing the second photosensitive pattern.

In addition, the photomask according to an embodiment of the present invention is manufactured by the above-described method, and includes a halftone pattern having a slit shape formed on at least one of the sidewalls facing each other among the plurality of light blocking patterns. It is characterized by having a structure.

In the photo mask according to the present invention, the halftone pattern may serve as the OPC pattern by a simple process of forming a slit-shaped halftone pattern on the sidewall of the light shielding pattern without using a conventional complicated Optical Proximity Correction (OPC) pattern. In addition, it is possible to simplify the photomask manufacturing process and to improve the manufacturing time and manufacturing efficiency by enabling the CD line width adjusting effect.

In particular, the present invention can omit the conventional OPC design design process or design redesign process for adjusting the CD line width, can significantly shorten the photomask manufacturing time, and can omit the OPC database and equipment Save equipment cost and equipment maintenance time for mask manufacturing It can be effective.

1 is a plan view showing a TFT channel region of a photomask according to the prior art.
2 is a plan view illustrating a TFT channel region of a photomask according to an embodiment of the present invention.
3 to 12 are cross-sectional views sequentially illustrating a method of manufacturing a photomask according to the present invention.
13 is a plan view illustrating a TFT channel region of a photomask according to another embodiment of the present invention.
FIG. 14 is a cross-sectional view illustrating a photomask cross section of the present invention shown in FIG. 13.
15 is a cross-sectional view illustrating a TFT channel region of a photo mask according to another embodiment of the present invention.

Hereinafter, a method of manufacturing a photo mask using a slit-shaped halftone pattern and a photo mask manufactured using the same will be described in detail based on the above-described object of the present invention.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments and drawings described below in detail. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, only the embodiments are to make the disclosure of the present invention complete, it is common in the art It is provided to fully inform those skilled in the art of the scope of the invention, which is to be defined only by the scope of the claims.

2 is a plan view illustrating a TFT channel region of a photomask according to an embodiment of the present invention.

The photo mask shown in FIG. 2 shows a portion for forming a channel region among photo masks for manufacturing a thin film transistor (TFT), and includes a first light blocking pattern 215a defining a source electrode on the transparent substrate 200. And a second light blocking pattern 215b defining a drain electrode.

In this case, the transparent substrate 200 may mainly be a quartz substrate having excellent light transmittance and mechanical properties.

Next, the first light blocking pattern 215a and the second light blocking pattern 215b are formed of a metal layer such as a chromium layer.

Here, when the electrode pattern is actually formed on the wafer using a photo mask in which only the simple light blocking patterns 215a and 215b are formed on the transparent substrate 200, the gap between the light blocking patterns 215a and 215b becomes narrower. The risk that the electrode pattern is short is increased.

Particularly, in the case of the TFT channel, the first light shielding pattern serving as the source electrode is formed by the letter 'c', and the second light blocking pattern serving as the drain electrode is formed in the shape of the letter '', so that the drain electrode is inserted into the source electrode. As a result, the density between the light blocking patterns is increased, and the probability of generating a short channel problem is increased.

In addition, a distortion of the pattern may occur at the edge portion (the “edge portion 140” of FIG. 1) into which the drain electrode is inserted, thereby reducing the open / short margin.

Accordingly, in order to prevent the distortion, the conventional optical proximity correction (OPC) pattern, which forms a separate auxiliary light shielding pattern in the distortion occurrence region, is used.

Although the OPC pattern is not illustrated in the present invention, the OPC pattern may be expected as a fine rectangular pattern or a circular pattern formed at the corners of the light shielding patterns 215a and 215b. At this time, assuming that the OPC patterns are applied to all of the light blocking patterns 215a and 215b, the shape of the light blocking patterns 215a and 215b has a very complicated shape.

Therefore, a problem may occur that design work for designing an OPC pattern, which is an auxiliary pattern, takes longer than designing only light blocking patterns 215a and 215b that define an actual circuit. In addition, since the distortion prediction region and the OPC pattern suitable for the region must be specified differently, even the capacity of the database for storing them individually increases exponentially. In addition, since a high-resolution exposure apparatus is required for a fine pattern forming operation such as an OPC pattern, and a fine pattern forming process must also proceed very precisely, there is a problem in that facility cost and time for forming an OPC pattern are increased.

These problems make it very inefficient and practically impossible to apply OPC patterns to a large number of photo masks.

In view of the above problems, the present invention provides a method of forming the slit-shaped halftone patterns 235a and 235b on the sidewalls of the light shielding patterns 215a and 215b, thereby replacing the role of the OPC pattern. use.

The halftone patterns 235a and 235b may be manufactured by only adding a halftone pad layer to the entire surface of the transparent substrate 200 during the light shielding patterns 215a and 215b.

In addition, in the present invention, in order to increase the open / short margin, the design process and the equipment cost generated by the OPC pattern forming process are performed by rounding the corners where the corners meet the corners, which are expected to be short. This can reduce the burden considerably.

In this process, the halftone pad layer remains on the light shielding patterns 215a and 215b, and the patterning process for forming the light shielding patterns 215a and 215b has to be divided into two stages. As it is a general pattern process, there is no burden on additional process.

Therefore, hereinafter, a specific method of the halftone pad layer forming step and the light shielding pattern forming step performed in two steps will be described.

3 to 12 are cross-sectional views sequentially illustrating a method of manufacturing a photomask according to the present invention, and illustrate a cross-sectional view taken along line A-A 'of FIG.

First, referring to FIG. 3, a light shielding layer 210 is formed on the entire surface of the transparent substrate 200. In this case, the transparent substrate 200 may be formed of a quartz substrate having excellent light transmittance and strength, and the light shielding layer 210 may be formed by depositing chromium (Cr).

Next, the first photosensitive film 220 is formed on the light blocking layer 210. At this time, the photosensitive film can be used as the photosensitive film type used in the semiconductor device manufacturing method using the wafer as it is, the following photosensitive film exposure, development, and manufacturing process can be used as a general semiconductor manufacturing process as it is.

Next, referring to FIGS. 4 and 5, the first photosensitive film 220 is exposed and developed to form a first photosensitive pattern 225 defining a first light blocking pattern and a second light blocking pattern.

4 illustrates a form in which the first photosensitive film 220 is exposed according to the pattern shape, and FIG. 5 illustrates a first photosensitive pattern 225 in which the photosensitive film exposed by the developer is removed.

In this case, the first light blocking pattern and the second light blocking pattern are formed in the form of the source electrode and the drain electrode described in the description of FIG. 2.

In addition, although not shown in the cross-sectional view, it is preferable to form the first photosensitive pattern 225 at the vertex portion of the source electrode and the vertex formed on the drain electrode facing each other so that each vertex is rounded.

Next, referring to FIG. 6, the light blocking layer 210 is etched using the first photosensitive pattern 225 as a mask to form a first light blocking pattern 215a defining a source electrode and a second light blocking pattern defining a drain electrode ( 215b). In this case, the etching of the light shielding layer may be preferably performed by using a reactive ion etching (RIE) process for easy etching of a metal layer such as a chromium layer.

Next, the first photosensitive pattern 225 is removed. In this case, the photosensitive pattern removing process uses a photosensitive film removing process performed in a general semiconductor manufacturing process, and the present invention is not limited by a solution or a removing method for removing the photosensitive pattern.

Next, referring to FIG. 7, a halftone pad layer 230 is formed on the entire surface of the transparent substrate 200 including the first light blocking pattern 215a and the second light blocking pattern 215b.

The halftone pad layer 230 corrects the intensity of light scattered at the boundary between the light shielding pattern constituting the photo mask and the light transmission pattern defined by the light shielding pattern so that the shape of the light shielding pattern can be formed more precisely. Doing. Therefore, it serves to reduce the CD deviation of the light shielding pattern formed in the subsequent process.

Next, referring to FIG. 8, a second photosensitive film 240 is formed on the halftone pad layer 230.

Next, referring to FIG. 9, the second photosensitive film is exposed to form a second photosensitive pattern 245 defining an actual circuit pattern.

In addition, referring to the illustrated embodiment, the second photosensitive pattern 245 is formed to form a portion of the first light blocking pattern 215a defining the source electrode. This is a result performed in consideration of the pattern difference between the main region and the channel region in the entire TFT mask.

Accordingly, the first light blocking pattern 215a or the second light blocking pattern 215b may be etched twice as needed. Such a shading pattern forming process may be seen in addition to the process, but a technique for forming a complete shading pattern while correcting a pattern difference between a main region and a channel region, and forming a shading pattern having a more precise shape than a conventional process. The present invention provides a method capable of further reducing the processing burden than forming fine light shielding patterns at once.

Next, referring to FIG. 10, the exposed second photosensitive pattern 245 may be developed to complete a second photosensitive pattern 245 in which a slit halftone pattern may be formed. The photosensitive pattern manufacturing process at this time also follows the general semiconductor manufacturing process as described above.

In addition, the second photosensitive pattern 245 is formed to have a size corresponding to the first light blocking pattern 215a and the second light blocking pattern 215b, and sidewalls of the first light blocking pattern 215a and the second light blocking pattern 215b. In this case, a half-tone pattern having a slit shape may be formed in at least one or more portions of the portions facing each other, so that a predetermined area is expanded.

In this case, if the extended area is defined as a line width with respect to the outer direction perpendicular to each sidewall of the first light blocking pattern 215a and the second light blocking pattern 215b, the line width of the extended area (hereinafter, referred to as a slit halftone pattern) Line width) is preferably formed to a size of 10 to 80% of the corresponding light shielding pattern line width.

When the line width of the slit-type halftone pattern is formed to be less than 10%, correction of light passing through the transparent substrate 200 is hardly achieved, and thus, a correction effect such as an OPC pattern cannot be obtained, and exceeds 80%. In the case where the size is formed to be large enough, the effect of improving the correction compared to the process investment for the pattern formation may not be greatly increased, which may be an unnecessary expansion.

Next, referring to FIG. 11, the halftone pad layer 230 is etched alone using the second photosensitive pattern 245 as a mask, or the halftone pad layer 230 and the first light blocking pattern 215a are sequentially formed. Perform the process of etching.

Next, referring to FIG. 12, the second photosensitive pattern 245 is removed to complete the manufacture of the photomask including the slit halftone pattern according to the present invention.

Here, the slit halftone pattern is formed by etching the halftone pad layer 230 alone, and the second slit halftone pattern 235b is defined on the sidewalls of the second light blocking pattern 215b. What is formed on the sidewalls of the first light blocking pattern 215a is defined as a first slit-type halftone pattern 235a.

In this case, the first slit halftone pattern 235a and the second slit halftone pattern 235b are not necessarily formed to face each other, and any one of them may be selectively formed.

This may be selectively performed in consideration of a more precise CD deviation prevention or an arrangement state of each light blocking pattern, and the like, but the present invention is not limited thereto.

FIG. 13 is a plan view illustrating a TFT channel region of a photo mask according to another exemplary embodiment of the present invention, and illustrates a case in which a slit halftone pattern is formed only on one sidewall selected from light blocking pattern sidewalls facing each other.

FIG. 13 illustrates a state in which a first light blocking pattern 320 defining a source electrode and a second light blocking pattern 330 defining a drain electrode are formed on the transparent substrate 300. Each light blocking pattern 320 or 330 is formed. ) Shows a photomask in which the slit-type halftone pattern 350 is formed only on the sidewall portion of the first light blocking pattern 320 among the portions facing each other.

Such a case can be applied to the case where a light shielding pattern having a line width of 2 to 3 μm is formed, and sufficient short channel problem or open / short margin can be solved. there was.

FIG. 14 is a cross-sectional view of the photomask of the present invention shown in FIG. 13, showing a cross section taken along line B-B '.

Referring to FIG. 14, it can be seen that the slit-type halftone pattern 350 is formed only on sidewalls of the first light blocking pattern 320 formed on the transparent substrate 300.

This is a case where only the second photosensitive pattern corresponding to the first light blocking pattern 320 is formed in an expanded form in the above-described second photosensitive pattern manufacturing process of FIGS. 8 to 10.

In addition, since the slit-type halftone pattern 350 is formed in a shape having a size of 10 to 80% of the light shielding pattern line width, the slit halftone pattern 350 is a fine pattern manufacturing process, but the first shading is not added to a special process for forming the slit. Since it is formed by the formation and etching of the halftone pad layer 340 to be applied to both the pattern 320 and the second light shielding pattern 330, it can be easily applied without a large process burden.

15 is a cross-sectional view illustrating a TFT channel region of a photo mask according to another embodiment of the present invention.

15, a slit halftone pattern 450 may be formed on sidewalls of the first light blocking pattern 420 formed on the transparent substrate 400, as shown in FIG. 14.

In this case, a halftone pad layer is applied to the first and second light blocking patterns 420 and 430 at the upper and lower portions thereof, and the lower first halftone pad layer 410 is formed on the entire surface of the transparent substrate before the light blocking pattern is formed. It can be formed after it is applied. Next, the second halftone pad layer 440 is formed on the first light blocking pattern 420 and the second light blocking pattern 430 to form a slit, thereby completing the present invention. In addition, such a process also has an effect that can be easily applied without a large burden.

As described above, the photomask completed according to the present invention forms a slit-type halftone pattern on the sidewalls of at least one of the light blocking patterns selected from among the light blocking patterns that are densely arranged to correct the distortion of the pattern when the actual pattern is formed using the photo mask. To be.

In addition, since the photo mask according to the present invention does not use a conventional complicated optical proximity correction (OPC) pattern, the OPC design design process can be omitted, and thus the photo mask manufacturing time can be drastically shortened, and the OPC database and The equipment can be omitted, saving equipment cost and equipment maintenance time for the photomask manufacturing.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood by those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

200, 300, 400: transparent substrate
210: light shielding layer
215a, 320, and 420: First Shading Pattern
215b, 330, and 430: second shading pattern
220: first photosensitive film
225: first photosensitive pattern
230, 340: halftone pad layer
235a: first slit halftone pattern
235b: second slit halftone pattern
240: second photosensitive film
245: second photosensitive pattern
350, 450: single slit halftone pattern
410: First halftone pad layer
440: second halftone pad layer

Claims (11)

In the method of manufacturing a photo mask comprising a plurality of light shielding patterns formed on the transparent substrate and a light transmitting region defined by the plurality of light shielding patterns,
A first halftone pad layer between the transparent substrate and the plurality of light blocking patterns, formed by rounding corner portions of sidewalls facing each other among the sidewalls of the plurality of light blocking patterns, and corresponding to the plurality of light blocking patterns A second halftone pad layer on the plurality of light blocking patterns, and corresponding to the sidewalls of the plurality of light blocking patterns, the first and second halftone pad layers, A method of manufacturing a photomask, the method comprising: forming a halftone pattern having a rounded slit shape along at least one of the sidewalls of the plurality of light blocking patterns facing each other.
delete The method of claim 1,
The line width of the halftone pattern is a photomask manufacturing method, characterized in that formed in the thickness of 10 to 80% of the line width of the light shielding pattern.
The method of claim 1,
The light blocking pattern may be a light blocking pattern defining a source electrode of a TFT film (Thin Film Transistor Channel) or a light blocking pattern defining a drain electrode.
The method of claim 1,
The transparent substrate is a manufacturing method of a photo mask, characterized in that the quartz (Quartz) substrate.
The method of claim 1,
The light shielding pattern is a photomask manufacturing method, characterized in that the chrome pattern.
delete delete delete Forming a first halftone pad layer on the entire surface of the transparent substrate;
Forming a light shielding layer on the first halftone pad layer;
Forming a first photoresist film on the light shielding layer;
Exposing and developing the first photoresist film to define a source electrode and a drain electrode, and forming a first photosensitive pattern such that vertex portions of sidewalls facing each other are rounded;
Etching the light blocking layer and the first halftone pad layer using the first photosensitive pattern as a mask to form a first light blocking pattern defining a source electrode and a second light blocking pattern defining a drain electrode;
Removing the first photosensitive pattern;
Forming a second halftone pad layer on an entire surface of the transparent substrate including the first light blocking pattern and the second light blocking pattern;
Forming a second photosensitive film on the second halftone pad layer;
Exposing and developing the second photoresist layer to correspond to the first light blocking pattern and the second light blocking pattern, wherein the first light blocking pattern and the second light blocking pattern are extended from the first light blocking pattern and the second light blocking pattern. Forming a second photoresist pattern in which a vertex portion corresponding to a vertex portion of the first light blocking pattern and a vertex portion of the second light blocking pattern facing each other is formed on at least one of the sidewalls facing each other; step;
Etching the second halftone pad layer or the second halftone pad layer and the first light blocking pattern using the second photosensitive pattern as a mask; And
And removing the second photosensitive pattern.
It is prepared by the method of any one of claims 1, 3 to 6 and 10,
A plurality of light shielding patterns formed on the transparent substrate, wherein a plurality of light blocking patterns having rounded vertices of the sidewalls facing each other among the respective sidewalls;
A first halftone pad layer formed between the transparent substrate and the light blocking pattern;
A second halftone pad layer formed on the light blocking pattern; And
And a halftone pattern having a slit shape formed on at least one sidewall among the sidewalls of the light blocking pattern and the first and second halftone pad layers that face each other.
The half-tone pattern is a photo mask, characterized in that the vertex portion corresponding to the area facing each other rounded.

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