KR20030049116A - A fabricating method of semiconductor device using ArF photolithography - Google Patents

Abstract

PURPOSE: A method for manufacturing a semiconductor device using ArF exposing source is provided to be capable of minimizing the deformation of a photoresist pattern while preventing contact defects. CONSTITUTION: An insulating layer(24) and an anti-reflective layer(25) are sequentially formed on a substrate(20) having conductive patters. A photoresist pattern(26) is formed on the anti-reflective layer(25) by using ArF exposing source. The anti-reflective layer and the insulating layer are partially etched by using the photoresist pattern as a mask while maintaining the temperature of substrate from -40°C to 10°C. The insulating layer(24) is partially etched by using the photoresist pattern(26) while maintaining the temperature of substrate from 20°C to 100°C. At this time, polymers are attached on the surface of the photoresist pattern(26). Then, a contact hole(30) is formed by removing the remaining insulating layer.

Description

A fabricating method of semiconductor device using ArF photolithography

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to semiconductor technology, and more particularly to a method of manufacturing a semiconductor device using an argon fluoride (ArF) exposure source.

The microfabrication technology that has supported the progress of semiconductor devices is a photolithography technology, and it is no exaggeration to say that the improvement in resolution of this technology is directly connected to the future of high integration of semiconductor devices.

As is well known, the photolithography process includes a process of forming a photoresist pattern and a process of etching a layer to be etched through an etching process using the photoresist pattern as an etch mask to form a pattern having a desired shape such as a contact hole. Wherein the photoresist pattern includes a process of applying a photoresist on the etched layer, a process of exposing the photoresist using a prepared exposure mask, and a portion of the photoresist exposed or not exposed with a predetermined chemical solution; Through the development process.

On the other hand, the critical dimension of the pattern that can be implemented by the photolithography process (hereinafter referred to as CD) depends on which wave source of light is used in the above exposure process. This is because the CD of the actual pattern is determined according to the width of the photoresist pattern that can be realized through the exposure process.

The wavelength of the light source used in the initial stepper adopting the “step and repeat” exposure method is from 436 nm (g-line) to 365 nm (i-line) and is now 248 nm (KrF Excimer Laser) wavelength. It mainly uses stepper or scanner type exposure equipment using DUV (Deep Ultra-violet). The 248 nm DUV photolithography initially produced a number of problems, such as time delay effects and substrate dependence. However, in order to develop a product having a design of 0.15 μm or less, it is necessary to develop a technology with a new DUV photolithography technique having a wavelength of 193 nm (ArF Excimer Laser). However, even if a combination of various techniques for enhancing the resolution in the DUV photolithography technique is impossible to pattern less than 0.1㎛, the development of a photolithography technique having a new light source is actively progressing.

At present, an ArF (argon fluoride) laser (λ = 193 nm) is being developed to target a pattern up to 0.11 mu m. DUV photolithography is superior in terms of performance and resolution compared to i-rays, but process control is not easy. These problems can be divided into optical causes due to short wavelengths and chemical causes due to the use of chemically amplified photoresists. If the wavelength is shortened, the CD shake phenomenon due to the stationary wave effect and the reflection of reflected light due to the substrate phase become worse. CD shaking refers to a phenomenon in which the line thickness changes periodically as the degree of interference between incident light and reflected light changes depending on the slight thickness difference of the photoresist or the thickness difference of the substrate film. In the DUV process, a chemically amplified photoresist has to be used to improve sensitivity, and problems related to the reaction mechanism include PED (Post Exposure Delay) stability and substrate dependence. Development of a photoresist for ArF. ArF is a chemically amplified type such as KrF, but the material needs to be fundamentally improved. ArF photoresist material development is difficult because benzene rings cannot be used. Benzene rings have been used in i-ray and KrF photoresists to ensure dry etching resistance. However, when the benzene ring is introduced into the ArF photoresist, since the absorbance is large at 193 nm, which is the wavelength region of the ArF laser, the transparency is lowered and thus the exposure to the lower portion of the photoresist is impossible. For this reason, the research of the material which can ensure dry etching resistance, does not have a benzene ring, and has good adhesive force and can develop in 2.38% TMAH is progressing. To date, many companies and research institutes in the world have announced their research results, but the commercially available polymers of COMO (CycloOlefin-Maleic Anhydride) or Acrylate system, or a mixture of these photoresists are It has a benzene structure as shown.

Therefore, during the process of landing plug contact (LPC, etc.), a stripe-shaped pattern may occur, or PR may cluster or form plastic deformation during SAC etching. During the development and SAC etching, the resistance of PR is weakened, so that it is driven to one side. Therefore, it is urgent to compensate for the weak durability of ArF photoresist and the weak physical properties of fluorine-based gas.

1 and 2 are cross-sectional views and SEM photographs showing pattern deformation and contact defects in the SAC process using the above-described ArF photoresist, respectively.

Referring to FIG. 1, a plurality of neighboring gate electrodes 11 are formed on a substrate 10, and nitride mask-based hard masks 12 are stacked thereon, and nitride-based spacers are formed along the profile. The insulating film 13 is formed, and the interlayer insulating film 14 is etched by the SAC etching process to open the gate electrodes 11.

At this time, in order to obtain an etching profile in the SAC process using a fluorine-based etching gas, the pattern is deformed by the fragility of the photoresist pattern, such as 'A' shown as shown in FIG. As shown in the SEM photograph.

In addition, excessive etching is performed to prevent contact open defects, and when misalignment occurs, loss of the gate electrode 11 and the hard mask 12 occurs as shown in FIG. Even if it is deteriorated and a misalignment does not occur, the contact width is narrowed as shown in 'C' to increase the contact resistance.

The present invention proposed to solve the above problems of the prior art, to provide a method for manufacturing a semiconductor device using an argon fluoride exposure source that can prevent contact defects and minimize the deformation of the photoresist pattern for ArF. have.

1 is a cross-sectional view showing the pattern deformation and contact defects in the SAC process using the ArF photoresist according to the prior art,

2 is a SEM photograph showing the pattern deformation and contact defects in the SAC process using the ArF photoresist according to the prior art,

3A to 3D are cross-sectional views illustrating a SAC etching process using a photoresist ArF exposure source according to an embodiment of the present invention;

Figure 4 shows a contact hole through the ArF photolithography process of the present invention shown in FIG.

* Explanation of symbols for the main parts of the drawings

20 substrate 21 gate electrode

22 hard mask 23 insulating film for spacer

24 insulating film 25 antireflection film

26 photoresist pattern 28 polymer

30: contact hole

In order to solve the above problems, the present invention includes the steps of sequentially forming an insulating film and an antireflection film on a substrate having a plurality of neighboring conductive patterns; Forming a photoresist pattern on the anti-reflection film by performing a photolithography process using an argon fluoride exposure source; Maintaining the substrate temperature at -40 ° C to 10 ° C and etching the thickness of the anti-reflection film and a portion of the insulating film using the photoresist pattern as an etching mask; Maintaining the substrate temperature at 20 ° C. to 100 ° C., etching the insulating film to an upper portion of the conductive pattern using at least the photoresist pattern as an etching mask, and generating a large amount of polymer to attach the photoresist to the surface; And forming a contact hole exposing the substrate surface between the conductive patterns by maintaining the substrate temperature at 20 ° C. to 100 ° C. and etching the remaining insulating layer using at least the photoresist pattern as an etch mask. A semiconductor device manufacturing method using an argon fluoride exposure source is provided.

According to the present invention, when the pattern is formed by using an ArF photoresist pattern such as COMA or acrylate, the low temperature process is appropriately performed during the etching of the antireflection film. When the insulating film is etched, a relatively high temperature process is performed. Particular etching is performed to the lower insulating film while the anti-reflection film is etched to prevent polymer generation at a low temperature of the substrate. At high temperature, fluorine and oxygen plasma are used to wrap around the photoresist pattern with a thick polymer to etch to the top of the gate hardmask, and then open the contact region using a gas containing fluorine and hydrogen under low pressure and high temperature conditions. Increases linearity to ensure wide contact area and minimizes pattern deformation And at the same time and with the technical features that minimize the gate electrode and the loss of the hard mask.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can more easily implement the present invention.

3A to 3D are cross-sectional views illustrating a SAC etching process using a photoresist ArF exposure source according to an embodiment of the present invention, which will be described in detail with reference to the drawings.

First, as illustrated in FIG. 3A, a plurality of conductive patterns in which silicides such as polysilicon and tungsten silicide are stacked on a substrate 20 on which various elements for forming a semiconductor device are formed, for example, a gate electrode 21 (hereinafter, referred to as a gate electrode) ).

That is, a gate insulating film (not shown) is formed at the contact interface between the substrate 20 and the gate electrode 21, and subsequent self-aligned etching (hereinafter referred to as SAC) on the gate electrode 21 is performed. A hard mask 22, such as a nitride film, is formed to prevent loss of the gate electrode 21.

Next, an insulating film 23 for a spacer such as a nitride film is placed along the entire profile where the gate electrode 21 is formed, and then, for example, an APL (Advanced Planarization Layer) oxide film, Boro Phospho Silicate Glass (BPSG), or SOG (Spin) is formed on the entire structure. An insulating film 24 such as On Glass or High Density Plasma (HDP) oxide film is formed.

Subsequently, after forming an organic anti-refrective coating 25 having a thickness of 100 kPa to 2000 kPa on the insulating film 24, an ArF photoresist is applied on the antireflective film 25, The photoresist pattern 26 is formed through a photolithography process using an ArF exposure source.

Specifically, an ArF photoresist, such as COMA or acrylate, is coated on the antireflection film 25 to a predetermined thickness, and then an argon fluoride exposure source (not shown) and a predetermined reticle (not shown) are used. To selectively expose a predetermined portion of the photoresist, and to leave the exposed or unexposed portion through the exposure process through the developing process, and then remove the etch residues through the post-cleaning process to remove the photoresist pattern 26. To form.

Next, as shown in FIG. 3B, the anti-reflection film 25 is selectively etched while keeping the temperature of the substrate 20 at -40 ° C. to 10 ° C. to prevent polymer generation. Some thickness etching is used to define the contact area for the SAC process.

At this time, since CxFy (x, y is 1 to 10) using a stock angle gas, since it maintains the temperature range of the above-mentioned version, the polymer is not produced and thus the cross-section after etching has a vertical profile as shown in '27'. Will have In this case, for reproducibility of the etching profile, an inert gas such as He, Ne, Ar, or Xe may be added alone or in combination.

Next, as illustrated in FIG. 3C, the substrate 20 is maintained at a high temperature of 20 ° C. to 100 ° C., and the insulating layer 24 is etched using the lower layer including the photoresist pattern 26 as an etching mask. The upper surface of the hard mask 22 is adjusted to be etched. At this time, a large amount of polymer 18 is generated and attached to the photoresist pattern 26.

At this time, CxFy gas is used as the stock gas under the above-described high temperature temperature, and the addition of O ₂ or Ar is added thereto to facilitate the production of the polymer 28.

Therefore, the etching stops on the hard mask 22 and the open portion 29 is formed on the contact plan region.

Next, as shown in FIG. 3D, the temperature of the substrate 20 is maintained at 20 ° C. to 100 ° C., and the insulating film 24 and the spacer insulating film are formed using the photoresist pattern 26 and the polymer 28 as an etching mask. (23) is etched to form a contact hole 30 exposing the surface of the substrate 20. At this time, a gas obtained by mixing CH ₃ F, CHF ₃ or CH ₂ F ₂ with CxFy is used as the stock angle gas. In addition, it is preferable to further use O ₂ or Ar gas for reproducibility of the etching process.

Accordingly, it can be seen that the pattern deformation is minimized as shown in the photograph after the application of the contact hole forming process through the ArF photolithography process shown in FIG. 4.

According to the present invention, the etching step is separated into three steps in the SAC process, and at this time, by appropriately adjusting the temperature of each step and enclosing the photoresist pattern around the etching conditions through the etching conditions for generating the polymer, the pattern deformation and the gate are performed. Through the examples it can be seen that the loss of the electrode can be minimized, and the contact area can be sufficiently secured.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible in the art without departing from the technical spirit of the present invention. It will be clear to those of ordinary knowledge.

The present invention described above can prevent deformation of the PR pattern and damage of the gate electrode according to the ArF photolithography process for forming the SAC, and can secure a wide contact area, thereby ultimately improving the yield of the semiconductor device. Excellent effect can be expected.

Claims (7)

Sequentially forming an insulating film and an anti-reflection film on a substrate having a plurality of neighboring conductive patterns formed thereon; Forming a photoresist pattern on the anti-reflection film by performing a photolithography process using an argon fluoride exposure source; Maintaining the substrate temperature at -40 ° C to 10 ° C and etching the thickness of the anti-reflection film and a portion of the insulating film using the photoresist pattern as an etching mask; Maintaining the substrate temperature at 20 ° C. to 100 ° C., etching the insulating film to an upper portion of the conductive pattern using at least the photoresist pattern as an etching mask, and generating a large amount of polymer to attach the photoresist to the surface; And Maintaining the substrate temperature at 20 ° C. to 100 ° C., and forming a contact hole exposing the surface of the substrate between the conductive patterns by etching the remaining insulating layer using at least the photoresist pattern as an etch mask. A semiconductor device manufacturing method using an argon fluoride exposure source comprising a. The method of claim 1, And CxFy (x, y is 1 to 10) as a stock angle gas in the step of etching the thickness of the anti-reflection film and the part of the insulating film. The method of claim 2, The semiconductor element method using an argon fluoride exposure source, characterized in that further comprising at least one gas of He, Ne, Ar, or Xe in the stock angle gas. The method of claim 1, And etching the insulating film to the upper portion of the conductive pattern, using a CxFy gas as a stock gas. The method of claim 4, wherein The method of manufacturing a semiconductor device using an argon fluoride exposure source, characterized in that to use the gas containing O ₂ or Ar in the stock corner gas in the step of etching the insulating film to the upper portion of the conductive pattern. The method of claim 1, The method of manufacturing a semiconductor device using an argon fluoride exposure source, characterized in that for forming the contact hole by etching the insulating film, a gas containing a mixture of CH ₃ F, CHF ₃ or CH ₂ F ₂ to CxFy as a stock angle gas. . The method of claim 6, The method of manufacturing a semiconductor device using an argon fluoride exposure source, characterized in that the stock corner gas further comprises O ₂ or Ar gas.