KR19990050484A - Method for manufacturing half-tone phase reversal mask - Google Patents

Abstract

The present invention relates to a method for manufacturing a half-tone phase inversion mask, comprising: forming a first phase inversion layer having a good etching selectivity with the transparent substrate on a transparent substrate; and a second phase on the first phase inversion layer. Forming a inversion layer, applying a photoresist on the second phase inversion layer, exposing and developing the photoresist to expose a predetermined portion of the second phase inversion layer, and using the photoresist as a mask Patterning a second phase inversion layer; and patterning the first phase inversion layer using the photoresist as a mask to expose a predetermined portion of the transparent substrate and remove the photoresist. Accordingly, the half-tone phase inversion mask according to the present invention is transparent by inserting another phase inversion layer by using a phase inversion material having a sufficient substrate and an etching selectivity between the transparent substrate and the existing phase inversion layer. Since the damage of the substrate is prevented and the phase error is reduced and the phase inversion layer of the multi-layer structure is formed, the transmittance can be easily controlled compared to the single layer.

Description

Method for manufacturing half-tone phase reversal mask

The present invention relates to a method of manufacturing a half-tone phase reversal mask, and more particularly, to a method of manufacturing a half-tone phase reversal mask capable of minimizing damage to a translucent plate generated during etching of a phase inversion layer.

In general, as semiconductor devices are highly integrated, the size of unit devices is reduced, and thus, a technique for forming a fine pattern has been studied.

Therefore, a binary intensity mask in which diffracted light generated by a pattern passes through a transparent lens of an exposure apparatus and forms an image on a wafer generates interference between the pattern and the desired contrast of the desired image. As a result, the half-tone phase shift mask has been studied to improve the resolution and the depth of focus.

In the half-tone phase inversion mask, a light shielding area of the mask is formed of a phase inversion material to partially transmit incident light, and invert the phase by 180 °. As a result, the 0 ° phase light and the 180 ° phase light in the transmissive region cause extinction interference to increase the contrast of the image. Therefore, the transfer efficiency of the pattern on the wafer is increased to improve process capability such as resolution and depth of focus.

1A to 1C are process diagrams showing a method for manufacturing a half-tone phase inversion mask according to the prior art.

In the related art, as shown in FIG. 1A, a phase inversion material having a constant refractive index such as MoSiO, Si _x N _y or TaSiO is deposited on a transparent substrate 11 having good light transmittance such as glass, quartz, or the like. The inversion layer 13 is formed. The phase inversion layer 13 is applied by a sol-gel method using an alcoholate-alcohol solution, or plasma chemical vapor deposition (hereinafter, referred to as plasma CVD). By vapor deposition). The phase inversion layer 13 should be formed to a predetermined thickness t to invert the phase of the incident light wavelength to 180 °, the thickness t being determined by the following equation.

t = λ / 2 (n-1)

Where? Is the incident light wavelength and n is the refractive index of the phase inversion layer 13. The refractive index n of the phase inversion layer 13 is different from that of the alcoholate-alcohol solution applied by the sol-gel method in the range of 1.6 to 2.3, and deposited in the plasma CVD method in the range of 2.5 to 3.5.

In addition, if the light extinction coefficient is k, the absorbance is α = 4πk / λ and the transmittance is T = exp (−αt). Thereafter, a photoresist 15 is applied onto the phase inversion layer 13.

Subsequently, as shown in FIG. 1B, the photoresist 15 pattern is formed by exposing and developing to remove a predetermined portion of the photoresist 15 to expose a predetermined portion of the phase inversion layer 13.

In addition, as shown in FIG. 1C, the exposed phase inversion layer 13 is dry-etched using a gas containing fluorine using the photoresist 15 pattern as a mask to expose a predetermined portion of the transparent substrate 11. A pattern is formed, and the remaining photoresist 15 is removed.

As described above, in the related art, a phase inversion layer is formed on a transparent substrate, and a pattern is formed by exposing a predetermined portion of the transparent substrate by dry etching using a photoresist.

However, most of the materials forming the phase inversion layer are damaged due to the etching gas used for etching the phase inversion layer because the quartz used as the transparent substrate and the sufficient etching selectivity cannot be secured. Damage to the transparent substrate causes a phase error, thereby reducing the phase reversal effect.

Accordingly, it is an object of the present invention to provide a method of manufacturing a half-tone phase reversal mask that can reduce damage to a transparent substrate to prevent phase error.

The method of manufacturing a half-tone phase inversion mask according to the present invention for achieving the above object comprises the steps of forming a first phase inversion layer having a good etching selectivity with the transparent substrate on a transparent substrate, and on the first phase inversion layer Forming a second phase inversion layer on the substrate; applying a photoresist on the second phase inversion layer; exposing and developing the photoresist; exposing a predetermined portion of the second phase inversion layer; and masking the photoresist. Patterning the second phase shifting layer using a light source; and patterning the first phase shifting layer using the photoresist as a mask to expose a predetermined portion of the transparent substrate and remove the photoresist. do.

1A to 1C are process diagrams illustrating a method for manufacturing a half-tone phase inversion mask according to the prior art.

2A to 2D are process diagrams illustrating a method of manufacturing a half-tone phase inversion mask according to an embodiment of the present invention.

<Brief description of symbols for the main parts of the drawings>

21: transparent substrate 23: first phase inversion layer

25 second phase inversion layer 27 photoresist

Hereinafter, with reference to the accompanying drawings will be described the present invention.

2A to 2D are flowcharts illustrating a method of manufacturing a half-tone phase inversion mask according to an embodiment of the present invention.

As shown in FIG. 2A, a phase inversion material such as Al / AlN and Zr / ZrN, which can be sufficiently etched with a chlorine-added material on a transparent light-transmitting substrate 21 such as glass or quartz, is shown in FIG. To form a first phase inversion layer 23, and deposit a phase inversion material that can be etched with a fluorine additive such as MoSiO, Si _x N _y or TaSiO on the first phase inversion layer 23 The two phase inversion layer 25 is formed. The first and second phase inversion layers 23 and 25 may be formed by applying a sol-gel method using an alcoholate-alcohol solution or by depositing by a plasma CVD method. The first and second phase inversion layers 23 and 25 have a predetermined thickness t by the combination of the first and second phase inversion layers 23 and 25 to invert the phase of the incident light wavelength by 180 °. The thickness t is determined by the following equation.

t = λ / 2 (n-1)

Where? Is the incident light wavelength and n is the index of refraction by the combination of the first and second phase inversion layers 23, 25. In addition, the light extinction coefficient must also be adjusted in accordance with the combination of the first and second phase inversion layers 23 and 25. Thereafter, a photoresist 27 is coated on the second phase inversion layer 25.

Thereafter, as shown in FIG. 2B, the photoresist 27 pattern is formed by exposing and developing the photoresist 27 to remove a predetermined portion of the photoresist 27 to expose a predetermined portion of the second phase inversion layer 25.

As shown in FIG. 2C, the exposed second phase shift layer 25 is dry-etched with a fluorine-added gas using the photoresist pattern 27 as a mask, thereby predetermining the first phase shift layer 23. Expose the part.

Thereafter, as shown in FIG. 2D, the exposed first phase shift layer 23 is dry-etched with a gas to which chlorine material is added using the photoresist 27 as a mask to remove a predetermined portion of the transparent substrate 21. A pattern for exposing is formed, and the remaining photoresist 27 is removed.

As described above, in the present invention, a first phase inversion layer that can be etched with chlorine-added gas and a second phase inversion layer that can be etched with conventional fluorine-added gas are formed on the transparent substrate, and are patterned by a multi-step dry etching method. Damage to the substrate was prevented.

Accordingly, the half-tone phase inversion mask according to the present invention further inserts another phase inversion layer by using a phase inversion material having a sufficient etch selectivity and a transparent substrate between the transparent substrate and the existing phase inversion layer. By preventing the damage of the phase error is reduced and the phase inversion layer of the multi-layer structure is formed, there is an advantage that the control of the transmittance is easier than the single layer.

Claims (3)

Forming a first phase inversion layer having a good etching selectivity with the transparent substrate on the transparent substrate; Forming a second phase inversion layer on the first phase inversion layer, Applying a photoresist on the second phase inversion layer, exposing and developing the photoresist to expose a predetermined portion of the second phase inversion layer; Patterning the second phase inversion layer using the photoresist as a mask; And patterning the first phase inversion layer using the photoresist as a mask to expose a predetermined portion of the transparent substrate and to remove the photoresist. The method of manufacturing a half-tone phase inversion mask according to claim 1, wherein Al / AlN, Zr / ZrN, or the like is used as the first phase inversion layer. The method of claim 1, wherein the etching gas of the first phase inversion layer uses a gas to which chlorine is added.