JPH0915832A - Semiconductor mask and its manufacture - Google Patents

Abstract

PURPOSE: To prevent the failure of the edge part pattern of a photosensitive film by providing a light adjusting layer formed on a substrate excluding a part to an edge part light transmission area, and a shading layer formed thereon, thereby reducing the intensity of light entering a center part in such a way as to be the same as the intensity of light entering the edge part of a mask. CONSTITUTION: In a light transmission area Te of an edge part of a semiconductor mask 50, incident light is transmitted through an exposed transmissive quartz substrate 40 to enter a wafer. In a light transmission area Tc of a center part, incident light is transmitted through a transmissive light adjusting layer 41 to enter the wafer. In the light transmission area Te of the edge part, the light is therefore transmitted as it is through the transmissive quartz substrate, but in the light transmission area Tc of the center part, the light is transmitted through the transmissive light adjusting layer 41 smaller in transmittance than the transmissive quartz substrate 40. The light entering the wafer through the transmissive light adjusting layer 41 is therefore reduced relatively in intensity compared to the light transmitted through only the quartz substrate 40 in the center area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor mask, and more particularly, to a mask capable of improving a photosensitive pattern at an edge by minimizing a proximity effect in a fine pattern and a method of manufacturing the same.

[0002]

2. Description of the Related Art Generally, a mask used in a semiconductor manufacturing process is manufactured by selectively forming a Cr thin film on a quartz substrate having high light transmittance.

FIGS. 1A to 1D show a manufacturing process of a conventional mask. As shown in FIG. 1A, a translucent quartz substrate 10
Is prepared, and a chromium thin film 11 is deposited on the entire surface of the prepared quartz substrate 10 as shown in FIG. Next, FIG.
As shown in (C), a photosensitive film 13 is formed on a portion of the chromium thin film 11 corresponding to the light shielding region S, and a portion of the chromium thin film 11 corresponding to the light transmitting region T is exposed. As shown in FIG. 1D, the chromium thin film 11 is etched using the photosensitive film 13 as a mask to form the light shielding layer 12. At this time, the chrome thin film 11 in the portion corresponding to the light-transmitting region T is etched to expose the light-transmitting substrate 10, and the light-shielding layer 1 is formed in the portion corresponding to the light-shielding region S.
2 are formed. As a result, a conventional lattice-shaped mask 20 is obtained.

FIG. 2A shows a sectional structure of the mask 20 manufactured by the manufacturing process of FIG. 1, and FIG. 2B shows FIG.
2A shows the intensity of light incident on the wafer through the mask 20 of FIG. The light incident on the wafer through the mask 20 is transmitted through the light transmitting region Tc in the central portion of the mask 20 in the light transmitting region T and the light transmitted through the edge portion of the mask 20 due to diffraction of the light itself. There is an intensity difference of ΔI between the light transmitted through the light region Te. When the conventional mask 20 is used to expose and develop a photosensitive film on a wafer, a light intensity difference of ΔI occurs between the central portion and the edge portion of the mask 20, so that the photosensitive film is not exposed. Floofile is as shown in Figure 3.

[0005]

As shown in FIG. 3, since the flow of the photosensitive film causes a difference between the edge portion and the central portion, the smaller the pattern size of the photosensitive film becomes, the more the pattern size of the photosensitive film becomes smaller after exposure and development. The obtained photosensitive film has a problem that a pattern defect occurs at an edge portion.

The present invention is to solve such a problem of the prior art, and reduces the intensity of light incident on a central portion so as to be the same as the intensity of light incident on an edge portion of a mask. It is another object of the present invention to provide a method of manufacturing a semiconductor mask capable of preventing a pattern defect at an edge portion of a photosensitive film.

[0007]

According to the present invention, there is provided a semiconductor mask according to the present invention, except that a light-transmitting quartz substrate divided into a light-transmitting region and a light-shielding region and an edge portion corresponding to the light-transmitting region are removed. And a light-shielding layer formed on the light-adjusting layer in the light-shielding region. The manufacturing method includes a step of preparing a quartz substrate, a step of forming a light adjusting layer on the prepared quartz substrate, a step of forming a light shielding layer on a light shielding area of the light adjusting layer, and a step of forming the quartz substrate into a light shielding area. The method includes a step of dividing the light-transmitting region into a light-transmitting region and a step of etching the light-transmitting light control layer corresponding to the light-transmitting region at the edge of the substrate.

The transparent light control layer can be formed to have a constant thickness from the central portion to the light transmitting region from the edge portion, and to be formed so as to be gradually thicker from the edge portion to the central portion. Can also.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a mask according to an embodiment of the present invention will be described below with reference to the drawings. 4 (A) to 4 (F) are process diagrams for manufacturing a mask according to an embodiment of the present invention. FIG.
A quartz substrate 40 is prepared as shown in FIG. 4A, and a translucent light adjusting layer 41 is formed on the prepared quartz substrate 40 as shown in FIG. 4B, and a translucent light adjusting layer 41 is formed as shown in FIG. A chromium thin film 42 is formed on the active light control layer 41. The translucent light control layer 41 is a layer for controlling the transmittance of incident light, and any material that can reduce the light transmittance as compared with the quartz substrate 40 having excellent light transmittance can be used. As the translucent light control layer 41,
A polyimide containing a dye, or an inorganic layer such as an oxide film or a nitride film is used. As shown in FIG. 4D, a photosensitive film 44 is applied on the chromium thin film 42 and is patterned to partition a light transmitting region T and a light shielding region S. Using the photosensitive film 44 as a mask, the chromium thin film 42 on the light transmitting region T is selectively etched to form a light shielding layer 43 on the light shielding region S as shown in FIG. After removing the photosensitive film 44, FIG.
As shown in (F), the translucent light control layer 4 including the light shielding layer 43
A photosensitive film 45 is further applied on the substrate 1 and patterned to expose the light-transmitting light control layer in the light-transmitting region Te at the edge of the light-transmitting region T. Next, as shown in FIG. 4G, the light transmitting region Tc at the exposed edge portion is etched.
Therefore, the light-transmitting light control layer 41 remains on the substrate in the light-transmitting region Tc in the center portion of the mask, and the light-transmitting light control layer 41 is removed in the light-transmitting region Te in the edge portion. The quartz substrate 40 is exposed. As a result, the semiconductor mask 50 according to the embodiment is obtained.

FIG. 5A shows a cross-sectional structure of a semiconductor mask 50 according to one embodiment, and FIG. 5B shows the intensity of light incident on a wafer through the semiconductor mask 50 of FIG. 5A. . In the light transmitting region Te at the edge portion of the semiconductor mask 50, the incident light is transmitted through the exposed light transmitting substrate 40 and is incident on the wafer, and in the central light transmitting region Tc, the incident light is transmitted. The light is transmitted through the light control layer 41 and is incident on the wafer. Therefore, the transparent region T of the edge portion
e, the light is transmitted through the translucent quartz substrate 40 as it is, but in the central transmissive region Tc, the translucent quartz substrate 4
Since light passes through the translucent light control layer 41 having a light transmittance smaller than 0, light incident on the wafer through the translucent light control layer 41 passes only through the quartz substrate in the central region. The intensity is relatively lower than that of the light. Therefore, the mask 5
The intensity of light incident on the wafer through the zero total light transmitting region T is the same.

FIGS. 6A to 6F show a manufacturing process of a mask according to another embodiment of the present invention. A quartz substrate 60 is prepared as shown in FIG. 6A, and a light-transmissive light control layer 61 is formed on the quartz substrate 60 prepared as shown in FIG. 6B. The translucent light control layer 61 is a layer for controlling light as in the embodiment, and may be made of any material that can suppress light transmittance as compared with the quartz substrate 60. As shown in FIG. 6C, a chromium thin film 62 is formed on the translucent light control layer 61, and a photosensitive film 64 is applied on the chromium thin film 62. The photosensitive film 64 is patterned to form a light transmitting region T and a light shielding region S. As shown in FIG. 6D, the chromium thin film 6 is selectively formed using the photosensitive film 64 as a mask.
2 is etched to form a light-shielding layer 63 on the light-shielding region S, exposing the light-transmitting light adjusting layer 61 in the light-transmitting region T. After removing the photosensitive film 64, as shown in FIG.
The photosensitive film 65 is further applied on the light-transmitting light control layer 61 containing 3 and patterned to expose the light-transmitting light control layer in the light-transmitting region Te at the edge of the light-transmitting region T. FIG.
As shown in (F), using the photosensitive film 65 as a mask, the transparent region T
Of these, the light transmitting region Te at the exposed edge portion is selectively etched to expose the substrate 61 at the edge portion.
After removing the photosensitive film 65, as shown in FIG. 6G, a photosensitive film 66 is further applied on the light transmitting light control layer 61 including the light shielding layer 63 and the exposed substrate 61, and is patterned. Of the light transmitting region T, the edge portion Te and the central portion T
The light-transmitting region Td between c is exposed. Using the photosensitive film 66 as a mask, the light transmitting light adjusting layer 61 in the exposed light transmitting region Td is etched by a certain thickness. At this time, the light transmitting region Td between the edge portion Te and the central portion Tc transmits less light than the edge portion Te, and the central portion Td.
In order to transmit more light than c, the light transmissive light control layer 61 in the light transmissive region Td between the edge portion Te and the central portion Tc is partially etched without being completely etched. Thus, a semiconductor mask according to another embodiment is obtained.

In the semiconductor mask 70 according to this embodiment, the light-transmitting light control layer 61 is entirely removed so that the quartz substrate is exposed so that light is completely transmitted in the light-transmitting region Te at the edge portion, and the light-transmitting region at the center portion is exposed. In the light region Tc, light is transmitted relatively slightly as compared with the light transmitting region Te at the edge portion.
The translucent light control layer 61 is left as it is without being etched.
The light transmitting region Td between the edge portion and the central portion transmits light slightly less than the light transmitting region Te at the edge portion, and transmits more light than the light transmitting region Tc at the central portion. The light-transmitting light control layer 61 is formed thinner than the thickness at the central portion.

In FIG. 6F, a single etching step is performed to form a light-transmitting light adjusting layer (61-) in the light-transmitting region Tc at the center.
2) rather than the light-transmitting region (T
d) The light-transmitting light control layer 61 is formed so that the light-transmitting light control layer (61-1) has a small thickness. It is also possible to form the light-transmissive light control layer 61 which becomes thinner as it goes.

[0014]

According to the present invention described above, a light-transmissive light adjusting layer having a light transmittance smaller than that of a light-transmitting quartz substrate is formed in a light-transmitting region in the center of a semiconductor mask. The light transmittance in the light transmitting region can be adjusted. Therefore, when the semiconductor mask of the present invention is used for forming a fine pattern, the proximity effect can be minimized, thereby improving the flowability of the photosensitive film at the edge portion, which is a problem in the conventional semiconductor mask, to improve the pattern. There is an advantage that occurrence of defects can be prevented.

[Brief description of the drawings]

FIG. 1 is a manufacturing process diagram of a conventional semiconductor mask.

2A is a cross-sectional structural view of a conventional semiconductor mask, and FIG. 2B is a diagram illustrating light intensity incident on a wafer through the semiconductor mask of FIG. 2A.

FIG. 3 is an electron microscope photograph of a photosensitive film patterned using the semiconductor mask of FIG. 2A.

FIG. 4 is a manufacturing process diagram of a semiconductor mask according to an embodiment of the present invention.

5A is a cross-sectional structure diagram of a semiconductor mask according to an embodiment of the present invention, and FIG. 5B is a diagram showing light intensity incident on a wafer through the semiconductor mask of FIG. 5A. is there.

FIG. 6 is a manufacturing process diagram of a semiconductor mask according to another embodiment of the present invention.

[Explanation of symbols]

50, 70 ... Semiconductor mask, 40, 60 ... Quartz substrate, 4
1,61: translucent light control layer, 42, 62: chromium thin film,
43, 63 ... Shading layer, 44, 64 ... Photosensitive film.

Claims (6)

[Claims] 1. A light-transmitting quartz substrate which is divided into a light-transmitting region and a light-shielding region, a light control layer formed on the substrate excluding a portion of the edge portion corresponding to the light-transmitting region, and a light control layer in the light-shielding region. And a light-shielding layer formed on the semiconductor mask. 2. The semiconductor mask according to claim 1, wherein the light adjusting layer is made of a material having a light transmittance lower than that of the quartz substrate. 3. A transparent quartz substrate which is divided into a light-transmitting region and a light-shielding region, and a quartz substrate excluding the light-transmitting region at the edge portion,
1. A semiconductor mask, comprising: a light control layer having different thicknesses in a central transmission region and other light transmission regions; and a light shielding layer formed on the light control layer in the light shielding region. 4. The semiconductor mask according to claim 4, wherein the light control layer has a thickness that decreases from the light transmitting region of the central portion to the light transmitting region of the edge portion. 5. A step of preparing a quartz substrate, a step of forming a light control layer on the prepared quartz substrate, a step of forming a light blocking layer on a light blocking area of the light controlling layer, and a step of forming the quartz substrate as a light blocking area. A method of manufacturing a semiconductor mask, comprising: dividing into light-transmitting regions; and etching the light control layer corresponding to the light-transmitting regions at the edge of the substrate. 6. A step of preparing a quartz substrate, a step of forming a light adjusting layer on the prepared quartz substrate, a step of forming a light shielding layer on a light shielding region of the light adjusting layer, and a transparent portion of an edge portion of the substrate. Etching the light control layer corresponding to the light region, and etching the light control layer between the edge portion and the center portion so as to have a thickness smaller than that of the light transmitting region of the center portion of the substrate. A method of manufacturing a semiconductor mask, comprising: