KR100532945B1 - Stencil mask and method for fabricating the same - Google Patents

Abstract

The present invention relates to a stencil mask and a method of manufacturing the same, and more particularly, to a stencil mask and a method of manufacturing the same that can balance the optimization energy (Eop) for various types of patterns. The stencil mask of the present invention functions to block a frame functioning to support the whole, a membrane disposed on the frame so as to balance the stress of the electron beam as a whole, and an electron beam disposed on the membrane and projected. An on / off type stencil mask having an aperture through which light projected from a light source is transmitted, the aperture including a relatively wide first region and a relatively narrow second region; The first region may be provided with a scattering layer for scattering the projected light.

Description

Stencil mask and its manufacturing method {STENCIL MASK AND METHOD FOR FABRICATING THE SAME}

The present invention relates to a stencil mask, and more particularly, to a stencil mask and a method of manufacturing the same, which can balance the optimization energy (Eop) for various types of patterns.

As the degree of integration of semiconductor devices increases, fine line width patterns are required. Here, the pattern of the fine line width is largely dependent on the light source used in the exposure process, and in order to realize a finer pattern of the line width, recently, an electron beam (E-beam), an ion beam (Ion-beam), and an X-ray An exposure process using a non-optical light source such as (X-ray) is performed.

On the other hand, in performing the non-optical exposure process, since the wavelength of the light source is short, about several hundreds to several hundreds of microseconds, when the general exposure mask is used, the light source cannot be transmitted, and thus the exposure process is not performed. Therefore, an on / off stencil mask is used in the exposure process using the light sources.

The stencil mask is a generic term for an exposure mask used in a non-optical exposure process. The stencil mask is a frame supporting the whole, a membrane disposed on the frame and functioning to balance the stress caused by the electron beam as a whole, and on the membrane. It consists of an absorber (Absorber) which is arranged to function to absorb or reflect the projected electron beam. In order to manufacture such a stencil mask, a silicon on insulator (SOI) wafer is conventionally used. As is well known, the SOI wafer is a laminated structure in which a buried oxide film and a silicon layer are sequentially formed on a silicon substrate.

1A to 1E are cross-sectional views illustrating a method of manufacturing a stencil mask according to the prior art.

First, as shown in FIG. 1A, an SOI wafer 10 having a buried oxide film 2 and a silicon layer 3 laminated on a silicon substrate 1 is prepared. Then, as shown in FIG. 1B. And patterning the silicon oxide film 11 on the entire surface of the SOI wafer 10 in a state where the hard mask silicon oxide film 11 is formed on the entire surface of the SOI wafer 10. By patterning the silicon layer 3 using (11) as a mask, an absorbing layer 3a made of silicon is formed.

Next, as shown in FIG. 1C, in order to prevent the absorption layer 3a from being damaged during the rear surface patterning while the silicon oxide film is removed, the nitride film 12 is deposited on the entire surface of the resultant product. .

Subsequently, as shown in FIG. 1D, the silicon substrate is patterned using the patterned silicon nitride film as a mask to form the frame 1a while the silicon nitride film portion deposited on the back surface of the silicon substrate 1 is patterned. Then, as shown in Figure 1e, by removing the silicon nitride film and the exposed buried oxide portion, the on / off stencil mask consisting of the frame (1a), the membrane (2a) and the absorbing layer (3a) ( Complete 20).

However, when the exposure process is performed using the on / off stencil mask manufactured through the above process, the transmission energy is changed depending on the size of the open area, that is, the aperture for the same exposure energy. By being partially different, there is a problem that a pattern of a desired shape cannot be obtained.

In detail, when the exposure process is performed using the on / off stencil mask 30 having the mask layout as shown in FIG. 2, the upper portion of the aperture is partially different from the upper surface of the upper aperture. The difference between the exposure energies that pass through each part of the lens will occur. As a result, when the resist pattern 40 as shown in FIG. 3 is obtained, the resist pattern portion B having a relatively wide width of the loss of the resist in the resist pattern portion A having a relatively thin width is obtained. Since the etching process is performed using the resist pattern 40 as a mask, the etching occurs relatively quickly in the resist pattern portion A of a relatively thin width, so that the critical dimension of the pattern (critical dimension) changes, and as a result, the pattern of the desired shape is not obtained.

This is a result due to the difference in the intensity of the exposure energy passing through the A portion and the intensity of the exposure energy passing through the B portion in the stencil mask shown in FIG. 2.

Therefore, the present invention devised to solve the above problems, the stencil to obtain a pattern of the desired shape by maintaining the exposure energy transmitted through all parts of the aperture having a partly different width uniformly The present invention provides a mask and a method of manufacturing the same.

The stencil mask of the present invention for achieving the above object is a frame that functions to support the whole, a membrane disposed on the frame and functions to balance the stress caused by the electron beam as a whole, and is disposed on the membrane An on / off stencil mask having an aperture through which an absorbing layer functions to block a projected electron beam, and the light projected from the light source is transmitted, the aperture being relatively wide with the first wide area. And a second region having a narrow width, wherein the first region is provided with a scattering layer for scattering the projected light.

In addition, the manufacturing method of the stencil mask of the present invention for achieving the above object comprises the steps of sequentially forming an oxide film, a scattering layer, a first hard mask film, a silicon layer and a second hard mask film on a silicon substrate; Patterning the second hard mask film and etching the silicon layer using the patterned second hard mask film as a mask so that an absorption layer having apertures of different widths is formed; Etching the portion of the exposed first hard mask layer, wherein the portion of the first hard mask layer is disposed in the relatively narrow aperture portion; Etching the exposed scattering layer part using the etched first hard mask layer as a mask; Removing the exposed portion of the first hard mask layer; Removing the second hard mask film and forming a silicon nitride film on the entire surface of the resultant product; Patterning the silicon nitride film to expose a portion of the lower surface of the silicon substrate, and etching the exposed silicon substrate part using the patterned silicon nitride film as a mask to form a frame; And removing the oxide film remaining in the silicon nitride film and the aperture portion.

According to the present invention, since the scattering layer is provided in the aperture portion having a relatively wide width, the intensity of the exposure energy in this region can be reduced, so that the exposure energy is determined based on the aperture portion of the wide width. By making it match, the exposure energy which permeate | transmits all the parts of an aperture which has a different width | variety can be kept uniform, and a pattern of a desired form can be obtained by this.

(Example)

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

4 is a plan view illustrating a stencil mask according to an embodiment of the present invention. As shown, the stencil mask 100 of the present invention has an open area, ie, an aperture, through which a light source passes, having a partially different width. When manufactured, a scattering layer 80 for scattering electron beams is provided in a relatively wide aperture portion, for example. Here, the scattering layer 80 is made of one material selected from silicon nitride (SiN), silicon nitride oxide (SiON), or titanium nitride (TiN). Further, in the drawings, portions other than the apertures represent absorbing layers that block light projected from the light source.

In more detail, FIG. 5 is a cross-sectional view taken along the line VV ′ of FIG. 4, and as shown, the stencil mask 100 according to the embodiment of the present invention has a frame 50 that functions to support the whole. And a membrane 60 disposed on the frame 50 so as to balance the stress caused by the electron beam as a whole, and an absorbing layer 70 disposed on the membrane 60 to block the projected electron beam. In addition, between the membrane 60 and the absorbing layer 70, for example, a scattering layer 80 capable of scattering electron beams is interposed, and in particular, the scattering layer 00 has a relatively wide width. It is placed exposed to the aperture portion of. Here, reference numeral 90, which is not described, is a hard mask film made of an oxide film used to pattern the scattering layer 80.

When the exposure process is performed using the stencil mask as described above, the intensity of the exposure energy is adjusted based on the region where the scattering layer 80 is disposed. That is, as the electron beam passing through the scattering layer 80 is scattered by the scattering layer 80, the energy of the electrons is reduced, and since the electron beam is scattered at a small angle, the electron density is changed. At this time, when comparing the electron beam transmitted through the scattering layer having the changed electron density with the normal electron beam transmitted through the aperture, the electron beam transmitted through the scattering layer has a relatively low electron density, and thus has a higher optimization energy.

Therefore, when the exposure energy is matched with respect to a portion having a higher optimization energy, that is, a relatively wide width and at the same time an aperture portion provided with a scattering layer, the intensity of the electron beam transmitted through this portion is actually applied to the electron beam. The intensity of the electron beam, which is reduced to the intensity of, but which passes through the relatively narrow aperture of the aperture, results in increased results, so that finally, the exposure energy in all parts of the aperture with partially different widths is uniform. You get a consistent result.

Therefore, when performing the exposure process using a stencil mask according to an embodiment of the present invention, as shown in Figure 6, it is possible to maintain uniformity in terms of the thickness of the resist pattern 110, accordingly, By securing the stabilization in the subsequent etching process, a pattern of a desired form can be obtained as a result.

7A to 7E are cross-sectional views illustrating a method of manufacturing a stencil mask according to an embodiment of the present invention.

First, as shown in FIG. 7A, an oxide film 42, a scattering layer 43, and a first hard mask layer 44 made of an oxide material for patterning the scattering layer 43 are formed on a silicon substrate 41. The silicon layer 45 is formed in order.

Then, as shown in FIG. 7B, in the state where the second hard mask film 46 is formed on the silicon layer 45, the second hard mask film 46 is patterned into a predetermined shape. By using the patterned second hard mask layer 46 as a mask, the silicon layer below is etched to form an absorption layer 45a made of silicon.

Next, as shown in FIG. 7C, the first hard mask film portion formed in the relatively narrow aperture portion is removed through a known process, and then the exposed scattering layer portion is removed. In this case, when the exposed scattering layer portion is removed, the first hard mask layer portion formed on the wider aperture portion is also removed.

Then, as shown in FIG. 7D, in order to prevent the absorption layer 45a from being damaged during the subsequent process for patterning the silicon substrate 41 with the second hard mask film removed, the entire surface of the resultant product. With the silicon nitride film 47 formed thereon, the silicon nitride film portion formed on the rear surface of the silicon substrate 41 is patterned, and then the exposed silicon substrate portion is etched using the patterned silicon nitride film as a mask. This forms the frame 41a.

Subsequently, as shown in FIG. 7E, the final stencil mask 100 is completed by removing the silicon nitride film and the oxide film disposed in the aperture portion.

As described above, the present invention includes a scattering layer in an aperture portion having a relatively wide width, so that the optimization energy at this portion is high, thereby making it possible to optimize uniformly at all portions of the aperture having a different width. It is possible to have energy, and accordingly, the thickness of the resist pattern can be secured, whereby a desired pattern can be obtained.

In addition, this invention can be implemented in various changes within the range which does not deviate from the summary.

1A to 1E are cross-sectional views illustrating a method of manufacturing a stencil mask according to the prior art.

2 is a plan view of a stencil mask having apertures of different widths.

3 is a photograph of a resist pattern obtained through an exposure process using the stencil mask of FIG. 2.

4 is a plan view of a stencil mask in accordance with an embodiment of the present invention.

FIG. 5 is a cross-sectional view of the stencil mask according to the embodiment of the present invention, taken along the line VV ′ of FIG. 4. FIG.

FIG. 6 is a photograph of a resist pattern obtained through an exposure process using the stencil mask of FIG. 5. FIG.

7A to 7E are cross-sectional views illustrating a method of manufacturing a stencil mask according to an embodiment of the present invention.

(Explanation of symbols for the main parts of the drawing)

41: silicon substrate 41a, 50: frame

42: oxide film 43, 80: scattering layer

44: first hard mask film 45: silicon layer

45a, 70 Absorbing layer 46 Second hard mask film

47 silicon nitride film 60

90: hard mask film 100: stencil mask

Claims (4)

A frame functioning to support the whole, a membrane disposed on the frame so as to balance the stress of the electron beam as a whole, and an absorption layer disposed on the membrane to block the projected electron beam. An on / off stencil mask having an aperture through which light projected from is transmitted, The aperture includes a relatively wide first region and a relatively narrow second region, wherein the first region is provided with a scattering layer for scattering the projected light. The method of claim 1, wherein the scattering layer, A stencil mask, characterized in that one selected from silicon nitride film (SiN), silicon nitride oxide (SiON), or titanium nitride film (TiN). Sequentially forming an oxide film, a scattering layer, a first hard mask film, a silicon layer, and a second hard mask film on the silicon substrate; Patterning the second hard mask film and etching the silicon layer using the patterned second hard mask film as a mask so that an absorption layer having apertures of different widths is formed; Etching the portion of the exposed first hard mask layer, wherein the portion of the first hard mask layer is disposed in the relatively narrow aperture portion; Etching the exposed scattering layer part using the etched first hard mask layer as a mask; Removing the exposed portion of the first hard mask layer; Removing the second hard mask film and forming a silicon nitride film on the entire surface of the resultant product; Patterning the silicon nitride film to expose a portion of the lower surface of the silicon substrate, and etching the exposed silicon substrate part using the patterned silicon nitride film as a mask to form a frame; And And removing the oxide film remaining in the silicon nitride film and the aperture portion. The method of claim 3, wherein the scattering layer, A method of manufacturing a stencil mask, characterized in that formed of one material selected from silicon nitride (SiN), silicon nitride oxide (SiON), or titanium nitride (TiN).