TWI477893B - Manufacturing method of photomask - Google Patents

Description

Photomask manufacturing method

The present invention relates to a method of fabricating a photomask, and more particularly to a method of fabricating a photomask applied to 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 that is 1:1 proportional to the pattern actually reproduced on the substrate, and the reticle used in the doubling lithography technique has a surface feature pattern size of Actually copied several times on the pattern on the substrate. Therefore, if a sub-micron or nano-scale feature pattern is to be reproduced on the substrate, the photomask used in the contact optical lithography technique can be very expensive, and at the same time, the metal pattern on the surface of the reticle and the photoresist on the substrate The contact friction of the layer is easy to cause the loss of the metal pattern to reduce the service life of the reticle; while the reticle used in the doubling lithography technology is cheaper, the exposure apparatus used requires a very high cost. In short, conventional optical lithography is quite difficult and expensive in sub-micron and nanoscale processes.

Therefore, how to provide a method for manufacturing a reticle, which is capable of reducing the cost on the sub-micron and nano-scale processes and prolonging the service life of the reticle, is one of the current important topics.

In view of the above problems, an object of the present invention is to provide a method of manufacturing a photomask capable of reducing the cost in a sub-micron and nano-scale process and extending the life of the photomask.

To achieve the above object, a method of fabricating a photomask according to the present invention includes: providing a substrate having a plurality of protrusions on one side of the substrate, one of the protrusions having a tapered structure at the top; and forming a light shielding layer on the substrate The side covers and covers the protrusions; forming an etch protection layer on the light shielding layer; etching a portion of the etch protection layer on top of the protrusions; and using the remaining etch protection layer as a mask to the light shielding layer Etching is performed.

In one embodiment, the material of the substrate comprises a metal material, quartz, a glass material, a ceramic material, a polymer series material, an organic material, a plastic material, a semiconductor material, an inorganic material, or both of the above materials. The materials synthesized above.

In one embodiment, the material of the substrate comprises a flexible material to create a flexible reticle. During the contact exposure process, the photomask and the photoresist layer can be closely adhered to reduce the gap between the two, thereby reducing the incident light reflectance of the light transmissive region and the photoresist layer, and avoiding the shallow portion of the photoresist layer. The lateral exposure range is expanded.

In an embodiment, the protrusions are arranged in an array, such as a one-dimensional array, or a two-dimensional array or a two-dimensional irregular arrangement.

In one embodiment, the projections are elongated or tapered.

In one embodiment, the material of the light shielding layer comprises a metal material, quartz, glass material, ceramic material, polymer material series material, organic material, plastic material, semiconductor material, inorganic material, or both of the above materials. Synthetic material. 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 material of the etching protection layer comprises a photoresist, a polymer series material, an organic material, a plastic material, a glass material, a ceramic material, quartz, or a material synthesized by any two or more of the above materials.

In one embodiment, the material of the etching protection layer comprises a metal material, a semiconductor material, an inorganic material, or a material synthesized by any two or more of the above materials.

In one embodiment, the etching of the etch protection layer is by a dry etch or a wet etch. The dry etching includes a plasma etching process such as a reactive ion etching (RIE) process or an inductively coupled plasma (ICP), and the wet etching is performed by etching.

In one embodiment, the etching of the light shielding layer is performed by dry etching or wet etching.

In an embodiment, the method of manufacturing the photomask further includes removing the remaining etching protection layer after the light shielding layer is etched. The removal of the remaining etch protection layer is performed by dry etching or wet etching.

As described above, the photomask made by the manufacturing method of the present invention has a light transmitting region which is a top portion of the convex portion on the substrate. Since the top portion has a tapered structure, the micron-sized mask pattern can be transferred to the substrate. The photoresist layer and makes it a characteristic pattern of sub-micron or nanoscale.

Since the present invention can reduce the conventional mask pattern to the sub-micron or nanometer level, it can be used to produce a sub-micron or nano-scale mask for use without using the expensive equipment required for doubling lithography. Therefore, the cost can be greatly reduced.

Further, the photomask produced by the manufacturing method of the present invention can be mounted on a mobile vehicle and subjected to mobile exposure to achieve diversification of the transfer pattern.

In addition, since the convex shape of the photomask of the present invention contacts the photoresist layer, and the light shielding layer is not disposed on the top of the convex material, the area of contact between the light shielding layer and the photoresist layer can be reduced, and the service life of the photomask can be prolonged.

In addition, since the top of the protrusion directly abuts against the photoresist layer, the photomask and the photoresist layer can be closely adhered 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. And if the photomask is made of a flexible material, the flexible mask makes the photomask and the photoresist layer more closely adhered, so that the dimensional error of the characteristic pattern transferred after the exposure is superior to the general contact optical micro Shadow technology. Moreover, the flexible reticle can make the light transmissive area of the reticle in close contact with the photoresist layer, thereby reducing the difficulty of one-time large area, uniform and consistent exposure.

In addition, since the top of the convex portion of the reticle of the present invention has a tapered structure, it is possible to produce a focusing effect on the incident light, and to reduce the diffusion range of the incident optical path.

In addition, the top of the convex portion of the reticle of the present invention is a light transmitting region of the reticle. By controlling the size of the top surface without the light shielding layer, the size of the feature pattern obtained after exposure can be adjusted.

In addition, the remaining etch protection layer of the present invention can be used as a protective layer of the light shielding layer to prevent wear or contamination of the light shielding layer and the photoresist layer, thereby prolonging the service life of the reticle while reducing the number of cleanings.

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 S05, and FIGS. 2A to 2E are schematic flow charts of the manufacturing method of FIG.

First, as shown in FIG. 2A, the manufacturing method includes providing a substrate 101 having a plurality of protrusions 102 on one side thereof, and a top portion 103 of each of the protrusions 102 has a tapered structure. The material of the substrate 101 is not particularly limited in the present invention, and includes, for example, a polymer series material (for example, polydimethyl siloxane (PDMS)), an organic material, a plastic material, a semiconductor material, an inorganic material, and a metal. A material, or a material synthesized by any two or more of the above materials. The material of the 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 substrate 101 is at least partially transparent. In addition, the material of the substrate 101 may comprise a flexible material such as polyethylene terephthalate (PET) to make a flexible reticle.

In this embodiment, the protrusions 102 can be arranged in an array, such as a one-dimensional array or a two-dimensional array, wherein the two-dimensional array contains irregular settings. Additionally, the protrusions 102 can be elongated, or tapered or otherwise geometric. As shown in FIG. 3, the protrusions 102 are arranged in a one-dimensional array and are elongated, and the protrusions 102 have a triangular cross section. As shown in FIG. 4, the protrusions 102 are arranged in a two-dimensional array and have a pyramid shape.

The top of the protrusion 102 is a tapered structure, and the tapered structure may be, for example, a tapered tapered structure, a trapezoidal tapered structure, or other tapered structure, and may include an asymmetric tapered structure.

Next, as shown in FIG. 2B, the manufacturing method includes forming a light shielding layer 104 on the side of the substrate 101 and covering the protrusions 102. Here, the light shielding layer 104 completely covers the side of the protrusion 102 and the substrate. The material of the light shielding layer 104 may include, for example, a metal material, a quartz material, a glass material, a ceramic material, 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. , or other materials. Here, the light shielding layer 104 is a metal layer. The light shielding layer 104 is used to cover the light emitted by the exposure light source, so the material thereof can be selected according to the type of the exposure light source.

Then, as shown in FIG. 2C, the manufacturing method includes forming an etch protection layer 105 on the light shielding layer 104. Here, the etching protection layer 105 completely covers the light shielding layer 104. The material of the etching protection layer 105 may include, for example, a photoresist, a polymer material series, an organic material, a plastic material, a glass material, a ceramic material, a quartz, a metal material, a semiconductor material, an inorganic material, or both of the above materials. The material synthesized.

The material of the etching protection layer 105 of this embodiment is exemplified by photoresist, and the photoresist can be formed by spin coating. The material of the etching protection layer 105 can be selected according to the material of the light shielding layer 104.

Then, as shown in FIG. 2D, the fabrication method includes etching portions of the etch protection layer 105 at the top 103 of the protrusions 102. By etching, the etching protection layer 105 can be formed with a notch and the light shielding layer 104 exposed. The etching of the etch protection layer 105 is performed by an etching process. The etching process can be dry etching or wet etching. The dry etching includes, for example, a plasma etching process such as a reactive ion etching (RIE) process or an inductively coupled plasma (ICP); and the wet etching is performed by etching with a suitable etching solution, for example, to form an anisotropic etching.

Next, as shown in FIG. 2E, the manufacturing method includes etching the light shielding layer 104 with the remaining etching protection layer 105 as a mask. The top 103 of the protrusion 102 can be exposed by etching the light shielding layer 104. The etching of the light shielding layer 104 can be performed by dry etching or wet etching, such as a reactive ion etching process. In the present embodiment, the top 103 of the protrusion 102 is the light transmitting area of the reticle 1.

5 is a schematic view showing exposure by 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 23a as shown in FIG. 6A. . Since the protrusion 102 of the reticle 1 directly abuts against the photoresist layer 21, the reticle 1 and the photoresist layer 21 can be closely adhered, 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 of the protrusion 102 is provided with a light shielding layer 104, so that the top 103 of the protrusion 102 is the light transmission area of the mask 1. Due to the above factors, the photomask 1 of the present embodiment can produce a high aspect ratio photoresist structure 23a, and the photoresist is exemplified by a positive photoresist. The photomask 1 of the present embodiment can also produce a high aspect ratio photoresist structure 23b, as shown in FIG. 6B, where the photoresist is exemplified by a negative photoresist. In addition, since the light shielding layer 104 is not disposed on the top portion 103, the area where the photoresist 1 is adhered to the photoresist layer 21 is greatly reduced, and the etching protection layer 105 can also prevent the light shielding layer 104 from contacting the photoresist layer 21, thereby extending The service life of the mask 1.

In this embodiment, the top portion 103 of the protrusion 102 can have a variety of variations, for example, the top surface of the top portion 103 can be curved, serrated, or other geometric shape. 7 to 9 are schematic views of the top portion 103 of the protrusion 102 having a curved surface and a sawtooth surface, and the shape of the protrusion 102 can be designed according to exposure requirements.

In addition, in order to obtain the reticle 1 shown in FIGS. 7 to 9, the manufacturing method may be such that in the step of providing the substrate (FIG. 2A), the top surface of the top portion 103 of the protrusion 102 is subjected to surface treatment to obtain an arc shape and a sawtooth shape. Shape or other geometric shape. Alternatively, after fabrication of the reticle 1 (Fig. 2E), the method of fabrication further includes surface treating the top 103 of the projection 102 to have an arcuate, serrated or other geometric shape.

10 is a schematic view showing exposure of the flexible reticle 1 and a curved substrate 31 of the present embodiment. The flexible reticle 1 is made of a flexible material and can be bent along with the curved substrate 31 to make light. The cover 1 and the substrate 31 are closely adhered to each other, thereby reducing the incident light reflectance of the light-transmitting region of the reticle and the photoresist layer and reducing the lateral exposure range of the photoresist layer.

Figure 11 is a schematic view of another embodiment of the reticle 1a of the embodiment. Wherein, the manufacturing method further includes removing the remaining etching protection layer 105 after the light shielding layer 104 is etched. The removal of the remaining etch protection layer is performed by dry etching or wet etching. Here, the remaining etch protection layer 105 is removed after completing the protection of the light shielding layer 104 to open the hole and exposing the top portion 103 as a light transmitting region of the reticle.

In summary, the photomask made by the manufacturing method of the present invention has a light transmitting area which is a top portion of the convex portion on the substrate. Since the top portion has a tapered structure, the micron-sized mask pattern can be transferred to the substrate. The photoresist layer and makes it a characteristic pattern of sub-micron or nanoscale.

Since the present invention can reduce the conventional mask pattern to the sub-micron or nanometer level, it can be used to produce a sub-micron or nano-scale mask for use without using the expensive equipment required for doubling lithography. Therefore, the cost can be greatly reduced.

Further, the photomask produced by the manufacturing method of the present invention can be mounted on a mobile vehicle and subjected to mobile exposure to achieve diversification of the transfer pattern.

In addition, since the convex shape of the photomask of the present invention contacts the photoresist layer, and the light shielding layer is not disposed on the top of the convex material, the area of contact between the light shielding layer and the photoresist layer can be reduced, and the service life of the photomask can be prolonged.

In addition, since the top of the protrusion directly abuts against the photoresist layer, the photomask and the photoresist layer can be closely adhered 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. And if the photomask is made of a flexible material, the flexible mask makes the photomask and the photoresist layer more closely adhered, so that the dimensional error of the characteristic pattern transferred after the exposure is superior to the general contact optical micro Shadow technology. Moreover, the flexible reticle can make the light transmissive area of the reticle in close contact with the photoresist layer, thereby reducing the difficulty of one-time large area, uniform and consistent exposure.

In addition, since the top of the convex portion of the reticle of the present invention has a tapered structure, it is possible to produce a focusing effect on the incident light, and to reduce the diffusion range of the incident optical path.

In addition, the top of the convex portion of the reticle of the present invention is a light transmitting region of the reticle. By controlling the size of the top surface without the light shielding layer, the size of the feature pattern obtained after exposure can be adjusted.

In addition, the remaining etch protection layer of the present invention can be used as a protective layer of the light shielding layer to prevent wear or contamination of the light shielding layer and the photoresist layer, thereby prolonging the service life of the reticle while reducing the number of cleanings.

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, 1a. . . Mask

101, 22. . . Substrate

102. . . Convex

103. . . top

104. . . Shading layer

105. . . Etched protective layer

twenty one. . . Photoresist layer

23a, 23b. . . Photoresist structure

31. . . Curved substrate

S01～S05. . . 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 2E are schematic flow charts of the manufacturing method of FIG. 1;

3 and FIG. 4 are schematic diagrams showing different manners of a substrate and a protrusion in a method of manufacturing a reticle according to a preferred embodiment of the present invention;

5 is a schematic view showing exposure of a photomask obtained by a method for manufacturing a photomask according to a preferred embodiment of the present invention;

6A and FIG. 6B are schematic diagrams showing a photoresist structure obtained by performing exposure using the photomask of FIG. 5;

7 to FIG. 9 are schematic diagrams showing a convex portion of a reticle having different aspects according to a preferred embodiment of the present invention;

10 is a schematic view showing exposure of a flexible photomask and a curved substrate according to a preferred embodiment of the present invention;

Figure 11 is a schematic illustration of another embodiment of a reticle in accordance with a preferred embodiment of the present invention.

S01～S05. . . Steps of manufacturing the mask

Claims (11)

A method for manufacturing a reticle comprises: providing a substrate having a plurality of protrusions on one side of the substrate, wherein one of the protrusions has a tapered structure at the top; forming a light shielding layer on the side of the substrate and covering Forming an etch protection layer on the light shielding layer; etching a portion of the etch protection layer on top of the protrusions; and etching the light shielding layer with the remaining etch protection layer as a mask . The method for manufacturing a reticle according to claim 1, wherein the material of the substrate comprises a metal material, a quartz material, a glass material, a ceramic material, a polymer material series, an organic material, a plastic material, a semiconductor material, and an inorganic material. A material or a material synthesized by any two or more of the above materials. The method of manufacturing a reticle according to claim 1, wherein the material of the substrate comprises a flexible material. The method of manufacturing a reticle according to claim 1, wherein the protrusions are arranged in an array. The method of manufacturing a reticle according to claim 1, wherein each of the convex shapes is elongated or tapered. The method for manufacturing a reticle according to claim 1, wherein the material of the light shielding layer comprises a metal material, a quartz material, a glass material, a ceramic material, 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 method for manufacturing a photomask according to claim 1, wherein the material of the etching protection layer comprises a photoresist, a polymer material, an organic material, a plastic material, a glass material, a ceramic material, a quartz material, a metal material. A semiconductor material, an inorganic material, or a material synthesized by any two or more of the above materials. The method of manufacturing a reticle according to claim 1, wherein the etching of the etch protection layer is performed by dry etching or wet etching. The method of manufacturing a reticle according to claim 1, wherein the etching of the light shielding layer is performed by dry etching or wet etching. The method for manufacturing a photomask according to claim 1, further comprising: removing the remaining etching protection layer after the light shielding layer is etched. The method of manufacturing a reticle according to claim 10, wherein the removing of the remaining etch protection layer is performed by dry etching or wet etching.