JPH05343307A - Rie dry development of sililated photoresist using o2/he plasma - Google Patents

Abstract

PURPOSE: To increase an etching rate and improve anisotropic etching and a resolution by conducting an RIE dry etching, using O2 /He gas which is O2 gas added with He gas and diluting a sililating agent with air or N2 in a sililation process of a photosensitive film. CONSTITUTION: The upper surface of a substrate 1 is coated with a plasma mask photosensitive film 2, including a pigment, and then a plasma mask photosensitive film 2 is exposed to light. In order to increase sililation selectivity between an exposed section 3 and a non-exposed section 4, presililation baking is conduced. Next, a sililation agent diffused layer 5 is formed in the steam, dilluted with air or N2 gas. Then, He which is an inactive gas is added in O2 gas, and dry etching is conducted to eliminate the non-exposed section 4 of the plasma mask 2. By this method, a rapid etching rate and a superior selectivity can be obtained, and resolution and contrast curve gamma can be enhanced, thereby obtaining, a superior lithography characteristic.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silylation and dry development technique of a photosensitive film which is a mask layer for forming a pattern during a semiconductor device manufacturing process. The present invention relates to an improved RIE dry development method for silylated photoresist using O ₂ / He plasma.

[0002]

2. Description of the Related Art In the field of optical lithography technology, the focus budget is reduced by a high NA lens according to the tendency of ultra-high integration of elements, the tilted photoresist profile due to absorption and the resist image due to the topography and reflectance of the substrate. It is a well-known fact that the problems such as the deterioration of the nation have come to the fore.

The multi-layered photosensitive film technology is to solve such a problem, and the process of forming the three-layered photosensitive film therein is, as shown in FIG. 1, a thick lower photosensitive film 12 on a substrate 11. After coating (a in FIG. 1), 180 ° C. to 2 ° C.
Hard baking is performed at a high temperature of about 00 ° C., and the intermediate layer 13 is vapor-deposited thereon (b in FIG. 1). Then, in order to improve the resolution, a thin photosensitive film 14 is coated on the upper surface of the intermediate layer 13 (c in FIG. 1). Here, since the photosensitive film 14 is thin, even if the intermediate layer 13 has a small defect, the photosensitive film 14 inevitably has a defect.

Next, the photosensitive film 14 as the image layer is partially exposed (d in FIG. 1), and the exposed portion of the photosensitive film 14 is removed using a developing solution (e in FIG. 1). ), An intermediate layer 13 is defined by using a dry etching technique (f in FIG. 1), and a lower photosensitive film 12 is further defined by using O ₂ gas while forming a mask layer for the next process. I did it.

However, since the photosensitive film 14 as the image layer is thinly coated, the resolution is increased, but on the other hand, even if the intermediate layer 13 has some defects, the image layer is the photosensitive film 14 and the defects are enlarged. As a result, defects of the substrate 11 are inevitably induced, and the process is complicated, which makes mass production impossible, resulting in a problem that productivity is reduced.

As a method for solving the problems of optical submicron lithography, there is a DESIRE (diffusion enhanced silylation resist) process utilizing a surface imaging technique, which is formed by surface imaging as a single layer photosensitive film structure. Since this is a method of dry-etching the photosensitive film pattern, the resolution and the process latitude can be improved.

[0007]

Dry etching is one of the most important process steps in DESIRE technology, which basically requires anisotropic etching and high selectivity of mask layer and photoresist. To do. This dry etching process is generally performed by RIE.
It is performed by MIE (Magnetically Enhanced Reactive Ion Etching), which has better etching speed and resolution than (Reactive Ion Etching), but it is difficult to maintain uniformity, so it is performed in the manufacturing process of semiconductor devices. However, by improving this characteristic, D
It turns out that applying it to ESIRE technology is a more effective method.

Accordingly, the present invention provides a silylated photoresist using O ₂ / He plasma, which has improved characteristics of RIE dry development such as increased etching rate, anisotropic etching, and improved resolution. It is an object of the present invention to provide an RIE dry development method.

[0009]

To this end, the present invention provides O
By using O ₂ / He gas in which He gas is added to ₂ gas to perform dry etching of RIE, an improved dry developing property is obtained, and a silylating agent is introduced into the air or air during the silylation process of the photosensitive film. By diluting with N ₂ , the uniformity of the front surface of the wafer is improved and the process latitude is improved.

[0010]

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

FIG. 2 shows a process sequence, and FIG. 2a shows a process of coating a plasmask photosensitive film on the upper surface of a substrate.

U containing dye (die) on the upper surface of the substrate 1
By coating the CB plasma mask photosensitive film 2 at a rotation of 4100 rpm to a thickness of about 1.6 to 1.8 μm, the reflectivity of the substrate 1 is increased by the plasma mask photosensitive film 2 included in a large thickness. To reduce the deterioration of the resist pattern due to topography.

FIG. 1b shows a process of exposing the plasma mask photosensitive film 2 to light, wherein the plasma mask photosensitive film 2 coated on the substrate 1 is soft-baked on a hot plate at a temperature of 110 ° C. for 60 seconds and then exposed. A state in which partial exposure is performed by using is shown.

In FIG. 3C, a pre-silylation baking is performed on a hot plate at a temperature of 160 ° C. for 60 seconds to increase the silylation selectivity of the exposed portion 3 and the unexposed portion 4 of the plasma mask photosensitive film 2. Shows the state of being done.

FIG. 3D shows a process of performing silation. After performing pre-silylation baking, TMSDEA which is a silencing agent is diluted with air or N ₂ gas at a temperature of 143 ° C. A state is shown in which the silylated agent diffusion layer 5 is formed on the upper end portion of the exposed portion 3 of the plasma mask photosensitive film 2 by carrying out silation for 7 minutes.

At this time, the uniformity of the front surface of the woofer is improved by diluting with air or N ₂ to improve the latitude of the process, while the adjustment of the silylation process is mainly performed by the amount of the diluted gas. The amount of silylated agent contained is adjusted by changing the temperature of the flask containing the agent.

FIG. 6e shows RI after performing silation.
The process of removing the non-sillated part, that is, the unexposed part 4 by using E or MIE is shown. He, which is an O ₂ inert gas, is added and dry etching is performed to perform RIE. The unexposed portion 4 of the plasma mask 2 was removed while obtaining an etching rate 4 to 5 times faster than that of the dry etching and the etching selection ratio of 20: 1 or more, which is superior to the MIE selection ratio (10 to 15: 1). Indicates the state.

[0018]

Therefore, depending on the method of forming the photosensitive film mask layer by the RIE dry development process of the present invention, the conventional R
The etching speed is 4 to 5 times faster than the IE etching speed and the selection ratio of 20: 1 or more, which is superior to the selection ratio of MIE (10 to 15: 1), can be obtained, and the resolution is 0.6 μm. It is possible to improve the resolution of development (0.75 μm), improve the contrast curve gamma, and obtain excellent lithographic properties.

[Brief description of drawings]

FIG. 1 is a schematic view showing the sequence of a conventional three-layer photosensitive film process.

FIG. 2 is a schematic view showing a process sequence of the present invention.

[Explanation of symbols]

 1 substrate 2 plasma mask photosensitive film 5 silylation agent diffusion layer

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Seong Jin Yoon Daejeong Eusunck Gajyundong 236-1 No. 23 (72) Inventor Byun Seong Park Daejeong Daeduk Dainjeong 179 Shinda Ejukon Apartment 113-302 (72) Inventor Young Jin Jaeong Daejeong Eusung Drongdong 383-3 Address Woosun Apart 102-504 (72) Inventor San Won-Kang Daejeong Junk Oryu-Dong Samsung Apartment 2-1502 (No address)

Claims (5)

[Claims] 1. A step of depositing a plasma-sensitive photoresist film (2) containing a dye on a substrate (1), a step of soft-baking the plasma-sensitive photoresist film (2) for partial exposure. A step of pre-silylation baking the exposed portion (3) and the unexposed portion (4) of the plasma mask photosensitive film (2), and the silylated agent diffusion layer (5) on the exposed portion (3). A silylated photoresist using O ₂ / He plasma, characterized in that a photoresist film mask layer is formed by a step of forming and a step of removing the unexposed part (4) by dry etching. RIE dry development method. 2. The step of forming the silylation agent diffusion layer (5) further comprises the step of performing silylation in a vapor of the silylation agent diluted with air or N _2. Item _{3. A} method of RIE dry development of silylated photoresist using O ₂ / He plasma according to Item 1. 3. The method of claim 1, wherein the step of performing the dry etching further includes the step of performing the dry etching using RIE in a state where He is added to O _2.
RIE dry development method of silylated photoresist using ₂ / He plasma. 4. The O ₂ / He of claim 1, wherein the coating step is performed at a thickness of 1.6 to 1.8 microns and a speed of 4100 rpm.
R of silylated photoresist using plasma
IE dry development method. 5. The soft baking step is 110 ° C.
The silylating agent diffusion layer 5 is formed at 143 ° C. for 7 minutes, and the pre-silylation baking step is performed at 160 ° C.
The RIE dry development method of a silylated photoresist using O ₂ / He plasma according to claim 4, wherein the RIE dry development is performed for 60 seconds.