KR0127660B1 - Method for fabricating phase shift mask of semiconductor device - Google Patents

Abstract

The present invention relates a method for making a phase shift mask of a semiconductor element. A sensitive film pattern is formed on a quartz substrate wherein the sensive film pattern sets photo transmission and non-transmission areas(A,B). The quartz substrate is etched in a predetermined depth by using the sensitive film pattern to form an etch groove(3) in the photo transmission area(A). A quarts substrate(1) in a boundary portion of photo transmission and non-transmission areas(A,B) which is divided based on a side wall of etch groove(3) is etched and a chrome pattern is formed on a quartz of the non-transmission areas(B) which was not etched. According to the present invention, a phase shift of 180= is generated at an edge portion of etch groove(3) defining a boundary of photo transmission and non-transmission areas(A,B) when a light is transmitted so that an intensity of a photo transmission becomes zero. Therefore, the present invention increases a process margin and resolution.

Description

Method of manufacturing phase inversion mask of semiconductor device

1A to 1H are cross-sectional views sequentially showing steps of manufacturing a phase inversion mask of a semiconductor device according to the present invention.

2 is a light intensity distribution diagram of the phase inversion mask of the present invention.

* Description of the symbols for the main parts of the drawings *

DESCRIPTION OF SYMBOLS 1 Quartz substrate 2 First photosensitive film | membrane

3: etching groove 3A: stair part

4,4A: second photosensitive film (negative photosensitive film) 5,5A: third photosensitive film

6: chrome 10: phase reversal disc

A: light transmission region B: light transmission region

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a phase shift mask of a semiconductor device. In particular, a photoresist pattern for setting a light transmission region and a non-transmission region is formed on a quartz substrate, and then quartz is etched using the photoresist pattern. The substrate is etched to a predetermined depth to form an etching groove in the light transmitting region, and the quartz substrate at the boundary between the light transmitting region and the light non-transmissive region which is separated from the sidewall of the etching groove by the back exposure method using the negative photosensitive film is etched again. By forming the chromium pattern only on the unetched quartz substrate of the light non-transmissive region, phase reversal occurs 180 ° at the edge of the etch groove which forms the boundary between the light transmissive region and the non-transmissive region during light transmission to increase the light transmission intensity. Because it is made of zero, it increases process margin and resolution when forming a semiconductor pattern. It relates to a method of manufacturing a phase shift mask of the crude rimhyeong (Rim Type) that may be applied to the process.

In general, a mask used in a lithography process of a semiconductor device includes a conventional mask in which a predetermined chromium pattern is formed on a quartz substrate and a phase inversion mask using a phase inversion material.

The general chromium mask is widely used in the manufacturing process of semiconductor devices, but as the semiconductor devices are highly integrated, there is a limit in forming a small chrome pattern of the mask, and the interference effect is generated between the patterns, thereby causing a fixed margin and resolution This decreases, making it impossible to apply to the manufacture of highly integrated semiconductor devices.

In addition, the phase inversion mask has better process margins and resolution than the general chromium mask, and is capable of lithography technology capable of coping with semiconductor devices of 64M DRAM or higher, and has a long wavelength G-line (γ =). 436 nm) and I-line (λ = 365 nm) and short wavelength Excimer Laser (λ = 248 nm) exposure systems. However, in order to fabricate the optimal phase inversion mask according to the semiconductor device, not only the design for installing the chrome pattern but also the phase material research and analysis and the related design are difficult problems, and the phase inversion is caused by the phase inversion. Because of the effect, the light transmittance is lowered and the light distribution contrast is somewhat lowered when used for DUV (Deep Ultra-violet) having a short wavelength.

Accordingly, an object of the present invention is to solve the shortcomings of a general chrome mask and to provide a method of manufacturing a rim type phase inversion mask which is easy to manufacture and increases the light distribution contrast while obtaining the process effect of a conventional phase inversion mask. have.

In order to achieve the above object, a method of manufacturing a phase shift mask according to the present invention comprises: setting a light transmitting region and a light non-transmissive region by patterning a first photosensitive film with an electron beam on a quartz substrate, and forming the patterned first photosensitive film. Etching the portion of the light transmission region, which is an exposed portion of the quartz substrate, to a predetermined depth by an anisotropic etching method as an etch stop layer, forming an etching groove, and removing the patterned first photoresist layer, and forming the etching groove Applying a second photoresist film over the entire surface of the substrate, exposing the second photoresist film to the back side, and developing a portion of the second photoresist film where the edge portion of the etch groove is exposed to light to form a patterned second photoresist film; An anisotropic etching method using the patterned second photoresist layer as an etch stop layer has a depth shallower than a predetermined depth of the etch groove for the quartz substrate exposed around the etch groove sidewalls. Etching to form a stepped portion at an edge of the light non-transmissive region, removing the patterned second photosensitive layer, and then applying a third photosensitive layer on the entire surface of the quartz substrate including the stepped portion and the etching groove, Etching the photosensitive film to an etch back to reach the depth of the step portion to leave a residual photoresist, depositing chromium on the entire structure by sputtering method, and removing the residual photoresist to remove the light Comprising a step of completing a rim phase inversion mask formed with etch grooves in the chromium and the quartz substrate of the light transmitting region formed as narrow as the step portion on the quartz substrate.

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

1A to 1H are cross-sectional views sequentially illustrating steps of fabricating a phase inversion mask of a semiconductor device according to the present invention.

FIG. 1A shows a state in which the first photosensitive film 2 is coated on a predetermined quartz substrate 1, and then the first photosensitive film 2 is patterned with an electron beam (E-Beam). The patterned first photoresist film 2 is set such that the pattern portion becomes the light non-transmissive region B and the etched portion becomes the light transmissive region A. FIG.

FIG. 1B is an anisotropic etching method using the patterned first photoresist film 2 as an etch stop layer to etch a portion of the light transmission region A, which is an exposed portion of the quartz substrate 1, to a predetermined depth. ), The patterned first photosensitive film 2 is removed.

FIG. 1C is a view illustrating a state in which the second photosensitive film 4 is applied on the entire surface of the quartz substrate 1 on which the etching groove 3 is formed, and then the back exposure process is performed. The peripheral portion of the second photoresist film 4 is not exposed due to the phase difference between the sidewalls of the etching grooves 3. In this case, the second photoresist film 4 uses a negative photoresist film.

FIG. 1D illustrates a state in which the non-exposed portion of the second photoresist film 4 is developed to remove the second photoresist film 4 at the sidewall portion of the etching groove 3 to form the patterned second photoresist film 4A. will be.

FIG. 1E illustrates a predetermined depth of the etch groove 3 with the quartz substrate 1 exposed about the sidewall of the etch groove 3 in an anisotropic etching method using the patterned second photoresist film 4A as an etch stop layer. It shows the state in which the stepped portion 3A is formed at the edge of the first etch groove 3 side wall outside, that is, the edge of the light non-transmissive region B by etching to a shallower depth.

FIG. 1F illustrates a state in which the third photosensitive film 5 is coated on the entire surface of the quartz substrate 1 including the step portion 3A and the etching groove 3 after removing the patterned second photosensitive film 4A. It is shown.

In FIG. 1G, the third photoresist film 5 is etched to a little less than the depth of the step portion 3A by an etch back process to leave the remaining photoresist film 5A, and then the chromium 6 is sputtered. ) Shows a state of being deposited.

1H shows that the chromium 6 narrowed by the step portion 3A on the quartz substrate 1 of the light non-transmissive region B by removing the remaining photoresist film 5A and removing the chromium 6 thereon. The quartz substrate 1 of the light transmitting region A is shown in a state where the phase inversion mask 10 of the present invention in which the etching grooves 3 are formed is completed.

The phase inversion mask 10 of the present invention manufactured by the above process uses a principle that 180 ° phase inversion occurs at the sidewalls of the etching groove 3, that is, the vertically etched edge, and shows a second light intensity distribution diagram. It is well shown in the figure. As shown in FIG. 2, when light is transmitted to the phase inversion mask 10, the phase inversion of 180 ° occurs at the sidewall of the etching groove 3, which is a boundary between the light transmission region A and the light transmission region B. By increasing the strength to 0 (zero), process margins and resolution are increased. Furthermore, a phase inversion effect can be obtained by using a quartz substrate having a good transmittance without using a phase inversion, thereby forming a better pattern of a semiconductor. have.

As described above, the phase inversion mask of the present invention is a rim type that etches a quartz substrate in a light transmission region to a predetermined depth, thereby obtaining a phase inversion effect without using a phase inversion material, thereby increasing process margin and resolution, and moreover, It has better transmittance than the phase inversion mask of, which makes it suitable for use in DUVs with long wavelengths as well as short wavelengths. It can be applied to the manufacturing process of highly integrated semiconductor devices having fine patterns. The phase inversion mask design is not particularly required and is easy to manufacture.

Claims (3)

Patterning the first photoresist film with an electron beam on the quartz substrate to establish a light transmission region and a light non-transmission region, and an exposed portion of the quartz substrate by an anisotropic etching method using the patterned first photoresist layer as an etch stop layer. Etching the portion of the phosphorescent region to a predetermined depth to form an etch groove, removing the patterned first photoresist film, and then applying a second photoresist film on the entire surface of the quartz substrate on which the etch groove is formed; Back exposing the second photoresist layer, developing a portion of the second photoresist layer where the peripheral portion of the etch groove sidewall is unexposed to form a patterned second photoresist layer, and anisotropic using the patterned second photoresist layer as an etch stop layer. Forming a stepped portion at an edge of the light non-transmissive region by etching the quartz substrate exposed around the etch groove sidewall by an etching method to a depth smaller than the predetermined depth of the etch groove. Removing the patterned second photoresist layer, and then applying a third photoresist layer on the entire surface of the quartz substrate including the stepped portion and the etching groove, and performing an etch back process on the third photoresist layer. Leaving the remaining photoresist film by etching so as not to be etched, depositing chromium on the entire structure by sputtering method, and removing the residual photoresist film, the chromium and light formed as narrow as steps on the quartz substrate in the light non-transmissive region. A method of manufacturing a phase shift mask of a semiconductor device, comprising the step of completing a rim type phase shift mask having an etch groove formed in a quartz substrate in a transmissive region. The method of claim 1, wherein a 180 ° phase inversion occurs at an etch groove sidewall, which is a boundary between the light transmitting region and the light nontransmissive region, so that the light intensity is zero. The method of claim 1, wherein the second photoresist film is a negative photoresist film.