TW201303488A - Manufacturing method of photomask - Google Patents

Abstract

A manufacturing method of photomask includes steps of providing a photomask substrate at which a patterned mask layer is disposed; etching the photomask substrate by using the mask layer as the mask so that a plurality of protruding portions protruding from a surface of the photomask substrate and having a top side and plural edge sides connecting the top side and the surface; forming a light-shielding layer on the etched photomask substrate and the mask layer; and removing a portion of the light-shielding layer so that at least one portion of each of the top sides is not covered by the light-shielding layer.

Description

Photomask manufacturing method

The present invention relates to a method of fabricating a reticle, and more particularly to a method of fabricating a reticle for use in contact optical lithography.

In the traditional optical lithography technology, the ultraviolet (UV) exposure technology of the photomask to the photoresist layer can be mainly divided into two types: contact optical lithography and doubling lithography.

The reticle used in the contact optical lithography technology has a surface feature pattern size of 1:1 in proportion to the pattern actually reproduced on the substrate, and is exposed directly to the surface of the photoresist layer; and doubling lithography The reticle used has a surface feature pattern size that is actually multiplied by a number of patterns on the substrate, and the photoresist is exposed by way of projection by an optical system.

Wherein, in the contact optical lithography technology, the metal pattern on the surface of the reticle is in contact with the photoresist layer on the substrate, which is easy to cause the metal pattern to be worn out, so that the life of the reticle is shortened, and when the reticle is coated with the photoresist layer The mask needs to be cleaned, and as the number of cleanings increases, the duration of use of the mask is shorter. In addition, when the surface of the substrate coated with the photoresist layer is not very flat, the photomask and the photoresist layer may generate an indefinite gap and distance, which may cause scattering and diffraction of light, thereby causing dimensional errors of the exposure and causing The lateral exposure range of the shallow portion of the photoresist layer is enlarged, so that a high aspect ratio photoresist structure cannot be produced.

In view of the above problems, an object of the present invention is to provide a method of manufacturing a photomask which can extend its service life and can produce a precise photoresist structure.

To achieve the above object, a method of fabricating a photomask according to the present invention includes: providing a photomask substrate having a patterned mask layer thereon; etching the photomask substrate with the mask layer as a mask, The reticle substrate has a plurality of convex portions protruding from a surface of the reticle substrate, each convex portion having a plurality of side surfaces and a top surface, the side surfaces connecting the top surface and the surface; forming a light shielding layer on the etched reticle And a portion of the light shielding layer is removed such that at least a portion of each of the top surfaces is not covered by the light shielding layer.

In an embodiment, each top surface is completely uncovered by the light shielding layer. That is, the top surface of the convex portion is the exposed light transmitting region.

In one embodiment, the manufacturing method further comprises: forming a transfer material layer on a mold core; forming an adhesive layer on the photomask substrate; and transferring a portion of the transfer material layer to the adhesive layer, thereby To provide a reticle substrate having a patterned mask layer, the mask layer includes at least a portion of the adhesive layer and a portion of the transfer material layer. This embodiment utilizes a metal contact transfer method to provide a mask layer.

In one embodiment, the portion of the opacifying layer is removed by a lift off process.

In one embodiment, the material of the photomask substrate is quartz, a glass material, a ceramic material, or a material synthesized by any two or more of the above materials.

In one embodiment, the material of the photomask substrate is a polymer material series material, an organic material, a plastic material, a semiconductor material, an inorganic material, a metal material, or a material synthesized by any two or more of the above materials.

In an embodiment, the material of the reticle substrate comprises a flexible material. The reticle thus produced is a flexible reticle, and the reticle and the photoresist layer can be closely adhered during the contact exposure process, thereby reducing the gap between the two, thereby reducing the light transmissive area and the photoresist layer of the reticle. The incident light is reflected and the lateral exposure range of the shallow portion of the photoresist layer is prevented from expanding.

In an embodiment, the lobes are arranged in an array.

In an embodiment, each of the convex portions is elongated, cylindrical, trapezoidal or other geometric shape.

In one embodiment, the material of the light shielding layer is a metal material, quartz, glass material, ceramic material, or a material synthesized by any two or more of the above materials.

In one embodiment, the material of the light shielding layer is a polymer series material, an organic material, a plastic material, a semiconductor material, an inorganic material, or a material synthesized by any two or more of the above materials. The material of the light shielding layer can be adjusted depending on the type of light source used for the exposure.

In one embodiment, the fabricated reticle is applied to contact optical lithography.

As described above, the photomask substrate produced by the manufacturing method of the present invention has a convex portion, and the top surface of the convex portion can be completely covered by the light shielding layer. Thereby, during the contact exposure process, the top surface of the convex portion of the reticle substrate directly abuts against the photoresist layer, and since the top surface has no light shielding layer, most of the light shielding layer is not subjected to the friction of the photoresist layer. Loss, which in turn extends the life of the mask. In addition, since the top surface of the convex portion directly abuts against the photoresist layer, the photomask and the photoresist layer can closely adhere to each other, thereby effectively reducing the gap between the photomask and the photoresist layer, thereby reducing the light reflectance between the two. The lateral exposure range of the photoresist layer can be reduced, and a high aspect ratio photoresist structure can be fabricated.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method of manufacturing a reticle according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings, wherein the same elements will be described with the same reference numerals.

1 is a schematic view showing the steps of a method for manufacturing a reticle according to a preferred embodiment of the present invention, which mainly includes steps S01 to S04, and FIGS. 2A to 2D are schematic flow charts of the manufacturing method of FIG. The photomask manufactured by the manufacturing method of this embodiment is exemplified by the application of the contact optical lithography technique. In addition, the photomask of the present embodiment is a phase shifting mask.

First, as shown in FIG. 2A, the manufacturing method includes providing a mask substrate 101 on which a patterned mask layer 102 is disposed. The material of the photomask substrate 101 is not particularly limited, and includes, for example, a polymer series material, an organic material, a plastic material, a semiconductor material, an inorganic material, a metal material, or both of the above materials. Synthetic material. The material of the mask substrate 101 is, for example, quartz, a glass material, a ceramic material, or a material synthesized by any two or more of the above materials, or other materials. The photomask substrate 101 needs to be at least partially transparent. In addition, the material of the reticle substrate 101 may comprise a flexible material to produce a flexible reticle.

The mask layer 102 is used as a mask to be etched, and the material of the mask layer 102 is not particularly limited in the present invention, and the material thereof may vary depending on the type of the etching process or the kind of the etching liquid. The mask layer 102 can be a single layer or a laminate, and the mask layer 102 is exemplified by a laminate.

Next, as shown in FIG. 2B, the manufacturing method includes etching the mask substrate 101 with the mask layer 102 as a mask, so that the mask substrate 101 has the plurality of convex portions 103 protruding from one surface 104 of the mask substrate 101, each of which The convex portion 103 has a plurality of side faces 105 and a top surface 106 that connect the top surface 106 to the surface 104.

Then, as shown in FIG. 2C, the manufacturing method includes forming a light shielding layer 107 on the mask substrate 101 and the mask layer 102 to be etched. The light shielding layer 107 is formed on the surface 104 of the mask substrate 101 and the side surface 105 of the convex portion 103, and the side surface and the top surface of the mask layer 102. The material of the light shielding layer 107 may be, for example, a polymer material series material, an organic material, a plastic material, a semiconductor material, an inorganic material, or a material synthesized by any two or more of the above materials. The material of the light shielding layer 107 is, for example, a metal material, quartz, a glass material, a ceramic material, or a material synthesized by any two or more of the above materials. The light shielding layer 107 is used to cover the light emitted by the exposure light source, but the material thereof can be selected according to the type of light.

Thereafter, as shown in FIG. 2D, the manufacturing method includes removing a portion of the light shielding layer 107 such that at least a portion of each of the top surfaces 106 is not covered by the light shielding layer 107. This embodiment is removed by a lift off process that removes the light shielding layer 107 on the mask layer 102 by removing the mask layer 102. Thereby, the manufacture of the reticle 1 can be completed. In this embodiment, each of the top surfaces 106 is completely uncovered by the light shielding layer 107, that is, the top surface 106 of the convex portion 103 is a light transmitting region of the mask 1.

3 is a schematic view showing exposure using the reticle 1 of the present embodiment, wherein the pattern of the reticle 1 is transferred onto a substrate 22 having a photoresist layer 21, so that the substrate 22 has a photoresist structure as shown in FIG. 4A. 23a. 4A illustrates the photoresist structure 23a with the photoresist layer 21 as a negative photoresist; in other words, the photoresist layer 21 can also be a positive photoresist layer, so that the substrate 22 can be made as shown in FIG. 4B after exposure and development. Photoresist structure 23b. Since the convex portion 103 of the reticle 1 directly abuts against the photoresist layer 21, the photomask 1 and the photoresist layer 21 can be closely adhered to each other, thereby effectively reducing the gap between the reticle 1 and the photoresist layer 21 and the lateral exposure range. And the reflectance between the photomask 1 and the photoresist layer 21 can be reduced. In addition, the side surface 105 of the convex portion 103 is provided with a light shielding layer 107, and thus the light transmitting region of the photomask 1 is the top surface 106 of the convex portion 103. Due to the above factors, the photomask 1 of the present embodiment can produce high-aspect ratio photoresist structures 23a, 23b. In addition, since the top surface 106 is completely free of the light shielding layer 107, the area where the photoresist 1 is adhered to the photoresist layer 21 is greatly reduced, and the portion of the light shielding layer 107 in contact with the photoresist layer 21 is greatly reduced and extended. The service life of the mask 1.

In addition, the reticle produced by the manufacturing method of the embodiment can have various aspects. For example, the protrusions 103 can be arranged in an array, such as a one-dimensional array or a two-dimensional array, and the protrusions 103 can be elongated, cylindrical, trapezoidal, or other geometric shapes. FIG. 5 is a schematic bottom view of the reticle 1 of FIG. 2D. Here, the convex portion 103 of the reticle 1 is exemplified by a long strip shape and arranged in a one-dimensional array.

Additionally, the top surface 106 of the convex portion 103 can be, for example, curved, serrated, or other geometric shape. 6 to 8 are schematic views showing the top surface 106 of the convex portion 103 in an arc shape and a zigzag shape, and the shape of the convex portion 103 can be designed according to exposure requirements.

The method of manufacturing the photomask of this embodiment will be additionally described below.

9A to 9D are schematic flow charts showing the steps of providing the mask substrate 101 (shown in FIG. 2A) having the mask layer 102 of the present embodiment. Here, the step of providing the photomask substrate is to apply a metal contact transfer method; of course, there are other methods for providing a mask substrate with a mask layer, such as optical lithography, electron beam lithography, and laser interference micro. Shadow technology or nano imprint technology.

As shown in FIG. 9A, a transfer material layer 301 is formed on a mold core 302. Here, the mold core 302 itself may have anti-stick properties or may form an anti-adhesion layer 304 on the surface of the mold core 302, such as As shown in FIG. 10, the transfer material layer 301 is a metal layer. One surface 303 of the mold core 302 has a concave portion and a convex portion, and the transfer material layer 301 is disposed along the concave portion, the convex portion, and the surface 303.

As shown in FIG. 9B, an adhesive layer 108 is formed on the photomask substrate 101. Here, the adhesive layer 108 is formed on one surface 110 of the photomask substrate 101.

Next, as shown in FIG. 9C, the mold core 302 is placed on the adhesive layer 108 of the photomask substrate 101, and after being pressed and baked, the portion of the transfer material layer 301 and the adhesive layer 108 is brought into contact with each other. The transfer portion is transferred onto the adhesive layer to form a transfer portion 109 as shown in Fig. 9D. Next, as shown in FIG. 9E, a portion of the adhesive layer of the adhesive layer 108 on the surface of the adhesive layer 108 is removed by etching or exposure development, thereby providing the mask substrate 101 having the patterned mask layer 102, And the mask layer 102 includes an adhesive layer 108 and a transfer portion 109 of the transfer material layer.

The above manufacturing method can also be adjusted depending on the implementation. For example, the adhesive layer 108 formed as shown in FIG. 9B may be previously defined with a patterned adhesive layer 108 via a lithography process, and then a portion of the transfer material layer 301 is transferred to the patterned adhesive layer 108, and then etched. The mask substrate 101 is obtained to obtain a mask substrate 101 as shown in FIG. 2B.

In addition, in order to obtain the mask substrate 101 shown in FIGS. 6 to 8, the manufacturing method may further include surface treatment of the mask substrate 101. The surface 110 of the mask substrate 101 can be surface treated, for example, by lithography, mechanical polishing, or chemical processing, for example, prior to forming the adhesive layer 108 on the surface 110 of the mask substrate 101 (FIG. 9B). . Alternatively, the top surface 106 is surface treated after the reticle 1 is formed (Fig. 2D).

As described above, the photomask substrate produced by the manufacturing method of the present invention has a convex portion, and the top surface of the convex portion can be completely not covered by the light shielding layer. Thereby, during the contact exposure process, the top surface of the convex portion of the reticle substrate directly abuts against the photoresist layer, and since the top surface has no light shielding layer, most of the light shielding layer is not subjected to the friction of the photoresist layer. Loss, which in turn extends the life of the mask. In addition, since the top surface of the convex portion directly abuts against the photoresist layer, the photomask and the photoresist layer can closely adhere to each other, thereby effectively reducing the gap between the photomask and the photoresist layer, thereby reducing the light reflectance between the two. The lateral exposure range of the photoresist layer can be reduced, and a high aspect ratio photoresist structure can be fabricated.

The above is intended to be illustrative only and not limiting. Any equivalent modifications or alterations to the spirit and scope of the invention are intended to be included in the scope of the appended claims.

1. . . Mask

101. . . Photomask substrate

102. . . Mask layer

103. . . Convex

104. . . surface

105. . . side

106. . . Top surface

107. . . Shading layer

108. . . Adhesive layer

109. . . Transfer section

110. . . surface

twenty one. . . Photoresist layer

twenty two. . . Substrate

23a, 23b. . . Photoresist structure

301. . . Transfer material layer

302. . . Mold

303. . . surface

304. . . Anti-adhesive layer

S01～S04. . . Steps of manufacturing the mask

1 is a schematic view showing the steps of a method for manufacturing a photomask according to a preferred embodiment of the present invention;

2A to 2D are schematic flow charts of the manufacturing method of FIG. 1;

3 is a schematic view showing exposure using a photomask according to a preferred embodiment of the present invention;

4A and FIG. 4B are photoresist structures obtained by exposure using a photomask according to a preferred embodiment of the present invention, wherein the photoresist layer of FIG. 4A is a negative photoresist, and the photoresist layer of FIG. 4B is a positive photoresist;

Figure 5 is a schematic bottom view of the reticle of Figure 2D;

6 to FIG. 8 are schematic diagrams showing a convex portion of a reticle having different aspects according to a preferred embodiment of the present invention;

9A-9E are schematic flow charts showing the steps of providing a photomask substrate having a mask layer according to a preferred embodiment of the present invention;

FIG. 10 is a schematic view showing a mold core provided with an anti-adhesion layer in a method of manufacturing a photomask according to a preferred embodiment of the present invention.

S01~S04. . . Steps of manufacturing the mask

Claims (12)

A method of manufacturing a reticle includes: providing a reticle substrate, wherein the reticle substrate is provided with a patterned mask layer; and the reticle layer is etched by using the mask layer as a mask, so that the reticle substrate has a plurality of convex portions protruding from a surface of the mask substrate, each of the convex portions having a plurality of sides and a top surface, the sides connecting the top surface and the surface; forming a light shielding layer on the etched mask substrate And the mask layer; and removing a portion of the light shielding layer such that at least a portion of each of the top surfaces is not covered by the light shielding layer. The method of manufacturing a reticle according to claim 1, wherein each of the top surfaces is completely uncovered by the light shielding layer. The method of manufacturing the reticle according to claim 1, wherein the step of providing the reticle substrate further comprises: forming a layer of a transfer material on a mold; forming an adhesive layer on the reticle substrate; And partially transferring a portion of the transfer material layer to the adhesive layer, thereby providing the reticle substrate having the patterned mask layer, the mask layer comprising at least a portion of the adhesive layer and the transfer This part of the material layer. The method of manufacturing a reticle according to claim 1, wherein the portion of the light shielding layer is removed by a lift-off process. The method of manufacturing a reticle according to claim 1, wherein the material of the reticle substrate is quartz, a glass material, a ceramic material, or a material synthesized by any two or more of the above materials. The method for manufacturing a reticle according to claim 1, wherein the material of the reticle substrate is a polymer material series, an organic material, a plastic material, a semiconductor material, an inorganic material, a metal material, or the above materials. A material synthesized by either or both. The method of manufacturing a reticle according to claim 1, wherein the material of the reticle substrate comprises a flexible material. The method of manufacturing a reticle according to claim 1, wherein the convex portions are arranged in an array. The method of manufacturing a reticle according to claim 1, wherein each of the convex portions is elongated, cylindrical or trapezoidal. The method of manufacturing a photomask according to claim 1, wherein the material of the light shielding layer is a metal material, a quartz material, a glass material, a ceramic material, or a material synthesized by any two or more of the above materials. The method for manufacturing a photomask according to claim 1, wherein the material of the light shielding layer is a polymer material series material, an organic material, a plastic material, a semiconductor material, an inorganic material, or both of the above materials. The material synthesized. The method of manufacturing a reticle according to claim 1, wherein the reticle to be manufactured is applied to a contact optical lithography.