KR100447974B1 - Method for forming photo resist pattrn - Google Patents

Abstract

The present invention discloses a method of forming a photoresist pattern that can prevent a collapse of a line space photoresist pattern. The disclosed photosensitive film pattern forming method includes applying a first photosensitive film made of an I-line photosensitive film on a semiconductor substrate to a thickness of 0.5 to 3.0 µm, and applying a negative second photosensitive film on the first photosensitive film. Exposing and developing the negative second photoresist layer to form a second photoresist pattern, silicifying the surface of the second photoresist pattern, and performing the silicided second photoresist pattern. Forming a silicon oxide film by performing an O2 plasma treatment, and forming a first photosensitive film pattern by performing O2 plasma etching on the first photosensitive film by using the second photosensitive film pattern on which the silicon oxide film is formed. Here, the first photosensitive film is hard baked at 100 to 300 ° C. for 50 to 300 seconds after its application. In addition, the second photosensitive film is coated with a thickness of 0.05 to 0.2 µm, and then soft baked at 100 to 120 ° C. for 80 to 100 seconds after the coating. In addition, the exposed second photoresist film was PEB-treated at 80-150 ° C. for 60-200 seconds, and the phenomenon of the PEB-treated negative photoresist film was 55-65 in 0.1-10% TMAH (TetraMethyl Ammonium Hydroxide) solution. This is done by dipping for seconds. In addition, the silylation treatment is performed at 110 to 130 ° C. for 80 to 100 seconds using a silylating agent such as hexamethyl disilazane.

Description

Photosensitive film pattern formation method {METHOD FOR FORMING PHOTO RESIST PATTRN}

The present invention relates to a method for forming a photoresist pattern, and more particularly, to a method for preventing a collapse of a fine line space photoresist pattern.

In manufacturing a semiconductor device, various patterns including contact holes are formed through a photolithography process. The photolithography process includes, as is well known, a process of forming a photoresist pattern and a process of etching the etched layer using the photoresist pattern as a mask, and the process of forming the photoresist pattern includes applying a photoresist on the etched layer. And a step of selectively exposing the photosensitive film by using a specific exposure mask, and a developing step of removing a portion of the photosensitive film exposed or exposed to a predetermined chemical solution.

On the other hand, as the pattern size decreases as the degree of integration of the device increases, the application thickness of the photoresist film is similar to the existing application thickness or the current one, but the aspect ratio of the photoresist pattern is relatively increased.

However, when the aspect ratio of the photoresist pattern is increased, there is no big problem in the case of the photoresist pattern for forming the contact hole, but in the case of the photoresist pattern for forming the line space pattern, the photoresist pattern is developed during the development process. Collapse of the pattern such as bending, bending, or detaching from the substrate occurs.

In this case, the photoresist pattern may be bent or bent. However, when the photoresist pattern is detached from the substrate, the photoresist pattern may be moved to another region. Thus, the pattern missing and the bridge may be caused by the movement of the photoresist pattern. Induced, and, in turn, results in a decrease in yield.

Herein, the collapse of the photoresist pattern is mainly caused during spin drying after DIW (deionizedwater) rinse during the development process, because of the surface tension of the DIW. When the photosensitive film pattern collapses, the surface tension of the rinse solution is larger, the narrower the gap between the pattern and the pattern, and the larger the aspect ratio of the photoresist pattern, the greater the surface tension of the rinse solution.

Therefore, the phenomenon of collapse of the photoresist pattern from Equation 1 can be achieved by a method of using a rinse solution having a small surface tension and a method of lowering the thickness of the photoresist pattern.

However, the former method is difficult to use because only the research on the material having a small surface tension is currently underway, and commercialization has not been achieved. In addition, the latter method is very easy, but when the coating thickness of the photoresist film is lowered, the photoresist pattern does not function as an etch barrier, and thus its use is practically difficult.

Accordingly, an object of the present invention is to provide a photosensitive film pattern forming method that can prevent the phenomenon that the fine line and space photosensitive film pattern is collapsed, which is devised to solve the above problems.

1 is a view for explaining the factors affecting the collapse phenomenon of the photosensitive film pattern.

2A to 2D are cross-sectional views of processes for describing a method for forming a fine line-n-space photosensitive film pattern according to an embodiment of the present invention.

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

1 semiconductor substrate 2 conductive layer

2a: conductive wiring 3: I-line photosensitive film

3a: lower photosensitive film pattern 4: negative photosensitive film

4a: upper photoresist pattern 5: silicon compound

5a: silicon oxide film 10: photosensitive film pattern

20: exposure mask

Method of forming a photosensitive film pattern of the present invention for achieving the above object, the step of applying a first photosensitive film made of I-line photosensitive film on a semiconductor substrate with a thickness of 0.5 ~ 3.0㎛; Applying a negative photoresist film on the first photoresist film; Exposing and developing the negative second photoresist to form a second photoresist pattern; Silylating the surface of the second photoresist pattern; Forming a silicon oxide film by performing O 2 plasma treatment on the silylated second photoresist pattern; And forming a first photoresist layer pattern by performing O 2 plasma etching on the first photoresist layer by using the second photoresist layer pattern on which the silicon oxide layer is formed.

The first photosensitive film is hard baked at 100 to 300 ° C. for 50 to 300 seconds after the application thereof.

In addition, the second photosensitive film is applied to a thickness of 0.05 to 0.2㎛, and soft baked at 100 to 120 ℃ for 80 to 100 seconds.

In addition, the exposed second photoresist film is PEB treated at 80 to 150 ° C. for 60 to 200 seconds, and the phenomenon of the PEB treated negative photoresist film is dipped in 0.1 to 10% of TetraMethyl Ammonium Hydroxide (TMAH) solution for 55 to 65 seconds. It is done in such a way as to.

In addition, the silylation treatment is carried out in hexamethyl disilazane, tetramethyl disilazane, bisdimethylamio dimethylsilane, bisdimethylamino methylsilane, dimethylsilyl dimethylamine, dimethylsilyl diethylamine, trimethylsilyl dimethylamine, trimethyl The silylating agent of any one of silyl diethylamine and dimethylamino pentamethyldisilane is used at 110 to 130 ° C. for 80 to 100 seconds.

According to the present invention, the photosensitive film pattern is formed in a two-layer structure, and the collapse of the upper photosensitive film can be prevented by lowering the coating thickness of the upper photoresist film, while the coating thickness of the lower photoresist film is thickened so that the photosensitive film pattern functions as an etching barrier. Can be.

(Example)

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

2A through 2D are cross-sectional views illustrating processes of forming a fine line-n-space photosensitive film pattern according to an embodiment of the present invention.

Referring to FIG. 2A, an etching target layer, that is, a conductive layer 2, is deposited on a semiconductor substrate 1 having a predetermined lower pattern (not shown), and the adhesion of the photoresist film to be applied thereafter is increased. The surface of the conductive layer 2 is surface treated with hexamethyl disilazane (HMDS) in a gas phase on a hot plate.

Then, an I-line photosensitive film 3 having a characteristic of excellent etching resistance was applied on the conductive layer 2 surface-treated with hexamethyl disilazane to a thickness of 0.5 to 3.0 µm, and 100 to about the resultant product. Hard bake is carried out at 300 ° C. for 50 to 300 seconds, preferably at 200 ° C. for 90 seconds.

Subsequently, the chemically amplified negative photosensitive film 4 reacting with KrF, ArF, EUV, E-beam, ion-beam, and X-ray light sources was subjected to 0.05 to 0.2 µm on the hard-baked I-line photosensitive film 3. Apply to thickness, and perform a soft bake on the resultant at 100-120 ° C. for 80-100 seconds, preferably at 110 ° C. for 90 seconds.

Next, using an arbitrary exposure mask 20, the negative photosensitive film is exposed to exposure equipment (NA = 0.6, Off-axis) equipped with an ArF light source. In this case, the exposure may be performed using an exposure apparatus having any one light source selected from KrF, EUV, E-beam, ion-beam, and X-ray instead of the exposure apparatus having an ArF light source.

The resultant is then subjected to a post exposure bake (PEB) treatment at 80 to 150 ° C. for 60 to 200 seconds, preferably at 110 ° C. for 90 seconds.

Referring to Figure 2b, the phenomenon for the negative photosensitive film exposed by dipping the resultant in 0.1-10%, preferably 2.38% TetraMethyl Ammonium Hydroxide (TMAH) solution for 55-65 seconds, preferably 60 seconds As a result, the upper photoresist pattern 4a is formed on the I-line photoresist 3. At this time, since the coating thickness of the upper photosensitive film pattern 4a is not high, in the above-described developing step, more precisely, no collapse occurs during spin drying in the developing step.

Referring to FIG. 2C, silylation of the resultant on which the upper photoresist pattern 4a is formed is performed for 80 to 100 seconds at 110 to 130 ° C., preferably at 120 ° C. for 90 seconds, using hexamethyl disilazane in the gas phase. ), And as a result, the silicon compound layer 5 is formed on the surface of the upper photoresist pattern 4a.

Here, as the silylating agent used in the silylation process, instead of the hexamethyl disilazane, tetramethyl disilazane, bisdimethylamio dimethylsilane, bisdimethylamino methylsilane, dimethylsilyl dimethylamine, dimethyl Any one selected from silyl diethylamine, trimethylsilyl dimethylamine, trimethylsilyl diethylamine, and dimethylamino pentamethyldisilane can be used.

Referring to FIG. 2D, the I-line photoresist film is dry-etched with O 2 plasma using the upper photoresist pattern 4a as an etch barrier, and the resulting lower photoresist pattern 3a and the upper photoresist pattern 4a are etched. The dry etching of the conductive layer using the configured photosensitive film pattern 10 forms a conductive line 2a such as a bit line. In this case, dry etching using the O2 plasma is performed under process conditions such that the flow rate of O2 is 35 sccm at a top power of 500 W, a bottom power of 100 W, a bias of 75 W, and a pressure of 30 ° C. and 5 mTorr. This is preferred.

Here, when dry etching using an O 2 plasma is performed after the negative photosensitive film is silylated, the hydroxyl group (-OH) contained in the negative photosensitive film is silylated to form a silicon compound layer, followed by an O 2 plasma etching step. The silicon oxide film 5a is formed.

Accordingly, the silicon oxide film 5a functions as an etching barrier during dry etching of the I-line photosensitive film, and thus, even if the coating thickness of the I-line photosensitive film is thickened, the silicon oxide film 5a may be formed by the difference in etching selectivity between the oxide film and the photosensitive film. The I-line photoresist can be etched.

In addition, since the I-line photoresist is not patterned by exposure and development, but by patterning by dry etching using an O 2 plasma, a collapse phenomenon by a developing process does not occur.

Accordingly, the present invention can form a fine line-n-space photosensitive film pattern in a two-layer structure, but can prevent the collapse phenomenon caused by lowering the coating thickness of the upper photosensitive film, and also, the silylation and O2 plasma for the upper photosensitive film pattern. By processing to form a silicon oxide film capable of functioning as an etch barrier on the surface thereof, it is possible to thicken the coating thickness of the lower photoresist film, and finally, to form a photoresist pattern having a coating thickness capable of functioning as an etch barrier to form a conductive layer such as a bit line The wiring can be formed stably.

As described above, according to the present invention, by forming the fine line-n-space photosensitive film pattern in a two-layer structure having a thick lower layer and an upper layer having a thin layer, the collapse phenomenon in the developing process can be prevented, thereby ensuring the reliability of the photosensitive film pattern. As a result, production yield can be improved.

In addition, the present invention can ensure the reliability of the fine line-n-space photosensitive film pattern, so that a fine-width line pattern can be easily formed, and thus can be advantageously applied to a highly integrated device.

Meanwhile, although specific embodiments of the present invention have been described and illustrated, modifications and variations can be made by those skilled in the art. Accordingly, the following claims are to be understood as including all modifications and variations as long as they fall within the true spirit and scope of the present invention.

Claims (8)

Applying a first photoresist film made of an I-line photoresist film on a semiconductor substrate to a thickness of 0.5 to 3.0 µm; Applying a negative photoresist film on the first photoresist film; Exposing and developing the negative second photoresist to form a second photoresist pattern; Silylating the surface of the second photoresist pattern; Forming a silicon oxide film by performing O 2 plasma treatment on the silylated second photoresist pattern; And And forming a first photoresist pattern by performing O2 plasma etching on the first photoresist layer using the second photoresist pattern on which the silicon oxide film is formed. delete The method of claim 1, wherein after applying the first photoresist film, before applying the second photoresist film, Hard baking the first photosensitive film at 100 to 300 ° C. for 50 to 300 seconds. The method of claim 1, wherein the second photoresist film is applied at a thickness of 0.05 to 0.2 μm. The method of claim 1, wherein after the applying of the second photoresist film, before the exposing of the second photoresist film, And soft-baking the second photosensitive film at 100 to 120 ° C. for 80 to 100 seconds. The method of claim 1, wherein after the exposing of the second photoresist film, before developing the second photoresist film, And subjecting the exposed second photoresist film to PEB treatment at 80 to 150 ° C. for 60 to 200 seconds. The method of claim 6, wherein the second photoresist is Method of forming a photoresist pattern, characterized in that the dipping for 0.1 to 10% TMAH (TetraMethyl Ammonium Hydroxide) solution for 55 to 65 seconds. The method of claim 1, wherein the sillation process Hexamethyl disilazane, tetramethyl disilazane, bisdimethylamio dimethylsilane, bisdimethylamino methylsilane, dimethylsilyl dimethylamine, dimethylsilyl diethylamine, trimethylsilyl dimethylamine, trimethylsilyl diethylamine and dimethylamino penta A method of forming a photoresist pattern, characterized in that it is performed at 110 to 130 ° C. for 80 to 100 seconds using any silylating agent selected from the group consisting of methyl disilane.