KR20110112726A - Method for fabricating a hole pattern by using a binary mask - Google Patents

Method for fabricating a hole pattern by using a binary mask Download PDF

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Publication number
KR20110112726A
KR20110112726A KR1020100032013A KR20100032013A KR20110112726A KR 20110112726 A KR20110112726 A KR 20110112726A KR 1020100032013 A KR1020100032013 A KR 1020100032013A KR 20100032013 A KR20100032013 A KR 20100032013A KR 20110112726 A KR20110112726 A KR 20110112726A
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KR
South Korea
Prior art keywords
pattern
film
light
opening
hole pattern
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KR1020100032013A
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Korean (ko)
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김신영
최규진
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주식회사 하이닉스반도체
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Priority to KR1020100032013A priority Critical patent/KR20110112726A/en
Publication of KR20110112726A publication Critical patent/KR20110112726A/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/027—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34
    • H01L21/0271—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34 comprising organic layers
    • H01L21/0273—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34 comprising organic layers characterised by the treatment of photoresist layers
    • H01L21/0274—Photolithographic processes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/027—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34
    • H01L21/033—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34 comprising inorganic layers
    • H01L21/0334—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34 comprising inorganic layers characterised by their size, orientation, disposition, behaviour, shape, in horizontal or vertical plane
    • H01L21/0337—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34 comprising inorganic layers characterised by their size, orientation, disposition, behaviour, shape, in horizontal or vertical plane characterised by the process involved to create the mask, e.g. lift-off masks, sidewalls, or to modify the mask, e.g. pre-treatment, post-treatment

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Preparing Plates And Mask In Photomechanical Process (AREA)
  • Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)

Abstract

The hole pattern forming method using the binary mask of the present invention comprises the steps of: forming a phase inversion film and a light blocking film on a light transmitting substrate; Patterning the light blocking film to form a light blocking film pattern including a first opening in which a hole pattern is to be formed and a second opening disposed around the hole pattern; Forming a resist film pattern that exposes the first opening while blocking the phase inversion film exposed by the second opening of the light blocking film pattern; Etching the phase shift film exposed by the first opening using the resist film pattern as an etching mask to form a hole pattern through which the light-transmitting substrate is exposed; And removing the resist film pattern to form a binary mask including an auxiliary pattern including a hole pattern and a phase inversion film exposed by a second opening disposed around the hole pattern; And transferring the hole pattern onto the wafer using a binary mask and exposure equipment including the hole pattern and the auxiliary pattern.

Description

Method for fabricating a hole pattern by using a binary mask}

The present invention relates to the manufacture of semiconductor devices, and more particularly, to a hole pattern forming method using a binary mask.

A photomask serves to form a desired pattern on the wafer by irradiating light onto a mask pattern formed on a transparent substrate having a light transmissive light to an exposure light source and transferring the selectively transmitted light to the wafer. This photomask plays an important role in determining the resolution of the pattern image transferred onto the wafer. In particular, as the degree of integration of semiconductor devices is increased and the size of patterns to be formed on wafers is further refined, an exposure process using a photomask serves as an important factor in forming a desired pattern on a wafer.

1 is a schematic cross-sectional view showing a general binary mask and a light intensity when an exposure light source passes through a photomask.

Referring to FIG. 1, the binary mask has a structure in which a substrate 100 having light transmissive to light and a light blocking film pattern 105 for blocking light are disposed. As the light blocking layer pattern 105 disposed on the substrate 100 selectively blocks the light source irradiated onto the substrate 100, the pattern of the opening 107 to which the substrate 100 is exposed is to be formed on the wafer. Becomes an image of. On the other hand, as semiconductor devices become highly integrated, as the design rule becomes smaller, the distance between adjacent openings 107 becomes smaller. Accordingly, when the exposure process is performed using a general binary mask, the light source passing through the opening has a relatively high intensity with respect to the phase inversion mask, but the intensity of the zero-order light is relatively strong. I don't have it Accordingly, there is a problem that the resolution of the pattern is significantly reduced. Phase inversion masks have been studied and applied as one of the ways to improve this problem.

2 is a cross-sectional view showing a general phase inversion mask and a diagram schematically showing the light intensity when the exposure light source passes through the photomask.

Referring to FIG. 2, the phase inversion mask has a structure in which the phase inversion film pattern 115 having a constant transmittance is disposed on the light transmissive substrate 110 instead of the light blocking film pattern. The phase inversion film pattern 115 disposed on the substrate 110 changes the phase of the wavelength of the light source irradiated onto the substrate 100 by 180 degrees, transmits a small amount of light to relatively reduce the size of zero-order light, Increasing the intensity of the primary light has a higher contrast value than the binary mask, resulting in a higher resolution of the pattern.

However, while the limit wavelength that can proceed in the exposure process is determined, the size of the pattern to be implemented on the wafer becomes smaller and the limit appears. In order to achieve a smaller pattern by applying various process technologies together, researches have been made on various disadvantages. Particularly, in the case of a hole type pattern including a contact hole, there is a limitation in the size of the pattern that can be realized due to a lack of a process margin in comparison with the line type pattern.

The technical problem to be achieved by the present invention is to increase the primary light intensity during exposure in the process of forming a fine hole pattern, and to reduce the zero-light intensity to improve the contrast to form a binary mask that can easily form a fine size hole pattern The present invention provides a hole pattern forming method.

A hole pattern forming method using a binary mask according to the present invention, forming a phase inversion film and a light blocking film on a transparent substrate; Patterning the light blocking film to form a light blocking film pattern including a first opening in which a hole pattern is to be formed and a second opening disposed around the hole pattern; Forming a resist film pattern exposing the first opening while blocking the phase inversion film exposed by the second opening of the light blocking film pattern; Etching the phase shift film exposed by the first opening using the resist film pattern as an etch mask to form a hole pattern through which the light transmissive substrate is exposed; And removing the resist layer pattern to form a binary mask including an auxiliary pattern formed of the hole pattern and a phase inversion film exposed by the second opening disposed around the hole pattern; And transferring the hole pattern onto a wafer using a binary mask and an exposure apparatus including the hole pattern and the auxiliary pattern.

In the present invention, the phase inversion film and the light blocking film may be formed in a structure that is sequentially stacked on the light transmitting substrate.

The forming of the resist film pattern may include forming a resist film on the light blocking film pattern, the resist film filling a phase inversion film having a portion of a surface exposed by the light blocking film pattern and the first and second openings; And forming a resist film pattern exposing the phase inversion film exposed by the first opening while blocking the phase inversion film exposed by the second opening by performing an exposure and development process on the resist film. It is preferable.

The first width of the first opening of the light blocking layer pattern may be formed to be relatively larger than the second width of the second opening.

The auxiliary pattern may be formed at a position facing each side of the hole pattern.

The auxiliary pattern may be formed to maintain a distance within the pitch of 1: 1 with the hole pattern.

According to the present invention, it is possible to improve the contrast characteristics by securing both the characteristics of the conventional binary mask and the phase inversion mask to reduce noise of zero-order light and to improve efficiency of the first-order light. In addition, by using a photomask, a hole pattern having a fine size can be realized by a direct method of transferring a pattern onto a wafer.

1 is a schematic cross-sectional view showing a general binary mask and a light intensity when an exposure light source passes through a photomask.
2 is a cross-sectional view showing a general phase inversion mask and a diagram schematically showing the light intensity when the exposure light source passes through the photomask.
3A to 3G are views illustrating a hole pattern forming method using a binary mask according to an embodiment of the present invention.
4 is a plan view schematically showing a binary mask formed by an embodiment of the present invention.
5 and 6 are views comparing the light intensity profile of the binary mask according to the present invention and the conventional phase inversion mask.
7 is a view showing for comparing the contrast of the binary mask and the conventional photomask according to the present invention when the photomask is irradiated with light.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

3A to 3G are views illustrating a hole pattern forming method using a binary mask according to an embodiment of the present invention. 4 is a plan view schematically showing a binary mask formed by an embodiment of the present invention.

Referring to FIG. 3A, a blank mask having a structure in which a phase inversion film 205, a light blocking film 210, and a first resist film 215 are sequentially stacked on a light transmissive substrate 200 is prepared. The light transmissive substrate 200 is made of a transparent material that can transmit an exposure light source, and includes quartz. The phase inversion film 205 formed on the light transmissive substrate 200 is made of a material having a transmittance of several percent, and includes a compound containing molybdenum (Mo). The compound containing molybdenum (Mo) may be formed including molybdenum silicon (MoSi). The light blocking film 210 formed on the phase inversion film 205 selectively blocks light transmitted to the light transmissive substrate 200 in the exposure process. The light blocking film 210 may include chromium (Cr). In addition, the first resist layer 215 formed on the light blocking layer 210 may define a region where a mask pattern is to be formed and serve as an etching mask. The first resist layer 215 may be formed of a positive type resist material in which a portion irradiated with light in the exposure process is removed during the development process, but is not limited thereto.

Referring to FIG. 3B, the first resist layer pattern 220 exposing a part of the surface of the light blocking layer 210 may be exposed by performing a first lithography process including an exposure process and a developing process on the first resist layer 215. Form. Specifically, an exposure process is performed on the first resist film 215. Subsequently, when the development process is performed, a portion of the first resist film 215 irradiated with light is removed by the developer and includes an opening (not shown) for exposing a portion of the surface of the light blocking film 210. The resist film pattern 220 is formed. In this case, the opening formed on the first resist film pattern 220 has a hole shape. Subsequently, the exposed portion of the light blocking film 210 is etched using the first resist film pattern 220 as an etch mask to form a light blocking film pattern 225 that selectively exposes the surface of the phase inversion film 205. Here, the first width a1 of the first region in which the hole pattern is to be formed as the main pattern in the exposed region of the phase shift film 205 is larger than the second width a2 of the second region in which the auxiliary pattern is to be formed. Form to have.

Referring to FIG. 3C, the first resist layer pattern 220 formed on the light blocking layer pattern 225 is removed by a strip process. When the first resist film pattern 220 is removed, the light blocking film pattern 225 is exposed, and the phase inversion film 205 is selectively exposed by the portion where the light blocking film pattern 225 is formed.

Referring to FIG. 3D, a second resist film 235 is coated on the light transmissive substrate 200. The second resist film 235 is formed to a thickness sufficient to fill the light blocking film pattern 225 and the phase inversion film 205 with a portion of the surface exposed. Here, the second resist layer 235 may be formed of a positive type resist material in which a portion irradiated with light in the exposure process is removed during the development process, but is not limited thereto.

Referring to FIG. 3E, a second resist film including an opening 245 defining a region in which a hole pattern is to be formed by performing a second lithography process including an exposure process and a developing process on the second resist film 235. The pattern 240 is formed. Specifically, when the exposure process is performed on the second resist film 235 and the development process is continued, a portion of the second resist film 235 to which light is irradiated is removed by the developer and the opening 245 is formed. Is formed. A portion of the surface of the phase inversion film 205 is exposed by the opening 245, and the exposed portion is a region where a hole pattern is formed by a subsequent process. Here, the second region having the size of the second width a2 (see FIG. 3B) where the auxiliary pattern is to be formed is covered with the second resist film pattern 240.

Referring to FIG. 3F, a phase including an opening that exposes the surface of the light transmissive substrate 200 by etching the phase inversion film 205 exposed by the opening 245 using the second resist film pattern 235 as an etching mask. The reverse film pattern 247 is formed. The opening disposed in the phase shift film pattern 247 is defined as a hole pattern 250.

Referring to FIG. 3G, the second resist layer pattern 235 having the light blocking layer pattern 225 and the phase inversion layer pattern 247 having a portion of the surface exposed by the light blocking layer pattern 225 is embedded in the strip process. Remove When the second resist film pattern 235 is removed, the light blocking film pattern 225 and the phase inversion film pattern 247 selectively exposed by the light blocking film pattern 225 are exposed to expose the phase inversion film pattern 247. The exposed portion of is defined as the auxiliary pattern 255 disposed around the hole pattern 250 as the main pattern. The hole pattern 250 is transferred onto a wafer (not shown) using a binary mask including the hole pattern 250 and the auxiliary pattern 255 and exposure equipment. Here, the exposure equipment at the time of transferring to the wafer may be an exposure equipment having a wavelength such as I-line, KrF, ArF, ArFi, EUV. In addition, the hole pattern transferred onto the wafer may be applied when forming a hole-shaped pattern of a semiconductor device including a cell array, for example, a contact hole, but is not limited thereto.

Referring to FIG. 4, which is a plan view showing a binary mask including a hole pattern formed according to an embodiment of the present invention from above, the binary mask of the present invention defines a light transmission area and a light blocking area on the light transmitting substrate 200. An auxiliary pattern 255 interposed between the light blocking film pattern 225, the light blocking film pattern 225, and the light-transmitting substrate 220, and having an exposed portion of the phase inversion film pattern 247 for generating a phase difference of transmitted light. It is composed. In this case, the light transmission region of the light transmissive substrate 200 exposed between the light blocking layer patterns 225 becomes a region of the hole pattern 250. The auxiliary pattern 255 defined by the exposed portion of the phase shift film pattern 247 is disposed adjacent to each other while facing each side of the hole pattern 250 as the main pattern. The auxiliary pattern 255 disposed to face each side of the hole pattern 250 may be disposed to maintain the interval within a 1: 1 pitch with the hole pattern 250.

 The binary mask including the hole pattern of the present invention is covered with the light blocking layer pattern 225 in which the remaining mask portion blocks the transmitted light except for the portion in which the auxiliary pattern 255 is disposed. When the auxiliary pattern is formed on the light-transmitting substrate, a problem arises in that the auxiliary pattern after actual exposure is transferred to the actual pattern on the wafer and formed. Accordingly, the size of the auxiliary pattern is limited in order to prevent the auxiliary pattern from being transferred onto the wafer. However, the present invention is not affected by the size of the auxiliary pattern by applying a phase shift material having a light transmittance of 6% or less as the auxiliary pattern. In addition, the binary mask according to the present invention has a structure in which a phase inversion film pattern 247 is inserted between the light transmitting substrate 200 and the light blocking film pattern 225. Accordingly, a defect due to misalignment can be prevented from occurring in a method of forming an auxiliary pattern by applying and patterning a phase shift material on the light blocking layer pattern.

5 and 6 are views comparing the light intensity profile of the binary mask according to the present invention and the conventional phase inversion mask.

FIG. 5A illustrates a phase inversion mask in which a hole pattern 300 implemented by a general phase inversion film pattern 305 is formed, and FIG. 6A illustrates a hole pattern according to an embodiment of the present invention. The auxiliary pattern 255 exposing the phase inversion film is disposed to face each side of 250, and the remaining portion except for the auxiliary pattern 255 and the hole pattern 250 includes a binary mask covered with the light blocking film pattern 225. Indicates. Referring to FIGS. 5B and 6B, in which the light intensity profile of each of these masks is represented as an aerial image through simulation, in the conventional phase shift mask, the phase shift film pattern ( 305) The distinction at the boundary is not clear, and the image at the center of the opening is not clear either. In contrast, in the present invention, it is confirmed that the distinction at the boundary of the light blocking layer pattern 225 is clear, and the image at the center of the opening is also clear. Accordingly, the light intensity of the portion of the hole pattern 300 (FIG. 6A) in the binary mask according to the present invention is the light intensity of the portion of the hole pattern 250 (FIG. 5A) in the conventional phase inversion mask. It can be confirmed that it appears higher. This difference in light intensity can lead to differences in contrast.

7 is a view showing for comparing the contrast of the binary mask and the conventional photomask according to the present invention when the photomask is irradiated with light.

Contrast is a measure of image modulation. As the contrast becomes higher, the difference between the bright and dark areas becomes clear, thereby accurately forming the image to be implemented. This contrast is determined by the maximum light intensity (Imax) value and the minimum light intensity (Imin) value in the following equation. (Contrast = (Imax-Imin) / (Imax + Imin))

Referring to FIG. 7, the maximum light intensity Imax of the binary mask A made of only the light blocking layer pattern is '0.26', which is higher than the maximum light intensity Imax of the phase inversion mask C, which is 0.17. In contrast, since the intensity of zero-blocking is relatively strong, the actual contrast value is represented by the binary mask A as '0.52' and the contrast value of the phase inversion mask C as '0.57', which is lower than the phase inversion mask. As a result, a higher resolution mask is realized in a phase mask than a binary mask. Although the phase inversion mask (C) changes the phase of the wavelength by 180 degrees, transmits a small amount of light to reduce the size of the zero-order light relatively, and increases the intensity of the first-order light, contrast is being studied. As the device is highly integrated, it is difficult to form a hole pattern having a finer size.

On the other hand, the binary mask according to the present invention reduces the noise of the zero order light and improves the efficiency of the first light by using the characteristic of reducing the magnitude of the zero order light of the phase inversion mask while securing the high light intensity value of the conventional binary mask. Appears as '0.60' to improve contrast characteristics.

In addition, photomasks can be used to implement hole patterns in a direct way to transfer patterns onto the wafer, enabling secondary processing techniques such as double patterning, spacer patterning, RELACS and reflow. Even without applying reflow, a hole pattern having a small size can be realized. Accordingly, it is possible to prevent a defect caused during the progress of the secondary process technology.

200: transparent substrate 205: phase inversion film
210: light blocking film 215: first resist film
225: light blocking film pattern 235: second resist film
250: hole pattern 255: auxiliary pattern

Claims (6)

Forming a phase inversion film and a light blocking film on the light transmitting substrate;
Patterning the light blocking film to form a light blocking film pattern including a first opening in which a hole pattern is to be formed and a second opening disposed around the hole pattern;
Forming a resist film pattern exposing the first opening while blocking the phase inversion film exposed by the second opening of the light blocking film pattern;
Etching the phase shift film exposed by the first opening using the resist film pattern as an etch mask to form a hole pattern through which the light transmissive substrate is exposed; And
Removing the resist layer pattern to form a binary mask including an auxiliary pattern formed of the hole pattern and a phase inversion film exposed by the second opening disposed around the hole pattern; And
And transferring the hole pattern onto a wafer using a binary mask and an exposure apparatus including the hole pattern and the auxiliary pattern. The method of claim 1,
And the phase inversion film and the light blocking film are formed in a stacked structure on the light-transmitting substrate in order. The method of claim 1, wherein the forming of the resist film pattern comprises:
Forming a resist film on the light blocking film pattern, the resist film filling a phase inversion film having a portion of the surface exposed by the light blocking film pattern and the first and second openings; And
Performing a process of exposing and developing on the resist film to form a resist film pattern exposing the phase inversion film exposed by the first opening while blocking the phase inversion film exposed by the second opening. Hole pattern formation method using a mask. The method of claim 1,
And a first width of the first opening of the light blocking layer pattern is larger than a second width of the second opening. The method of claim 1,
And the auxiliary pattern is formed at a position facing each side of the hole pattern. The method of claim 1,
The auxiliary pattern is a hole pattern forming method using a binary mask is formed so as to maintain a distance within the 1: 1 pitch with each of the hole pattern.
KR1020100032013A 2010-04-07 2010-04-07 Method for fabricating a hole pattern by using a binary mask KR20110112726A (en)

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