KR960000713Y1 - Vapor phase coating apparatus - Google Patents

Abstract

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Description

Weather spreading device

1 is a view showing a schematic structure of a conventional silylation vapor coating apparatus,

2 is a schematic cross-sectional view of a conventional filter employed in a conventional silylation vapor phase coating apparatus.

(a) is for the radial filter,

(b) is for mesh filters,

3 is a view showing a schematic structure of the vapor phase coating apparatus according to the present invention,

4 is a cross-sectional view of the filter employed in the vapor phase coating apparatus of the present invention.

(a) is a partially enlarged longitudinal sectional view of the filter

(b) is a cross-sectional view showing the overall appearance,

5 is a graph showing the uniformity of the silylation film obtained after performing the sililation process by employing several filters.

(a) is a conventional radial filter

in the case of using a meteorological spreading device employing (b),

(c) is a conventional mesh filter

In the case of using the weather spreading device employing (d),

(e) is the regularity filter of the present invention

For membranes obtained when a vapor phase coating apparatus employing (f) is used.

* Explanation of symbols for main parts of the drawings

1 gas inlet 2 filter

3: upper plate 4: lower plate

5: direction of injection gas 6: wafer

7 end of gas injection port 8 upper peripheral wall of through hole

9: part not through hole 10: lower part of through hole

The present invention relates to a vapor phase coating apparatus employing a matrix type filter, and in particular, a matrix type filter which can improve the resolution of a fine pattern by greatly improving the uniformity of the silylated layer formed on the photoresist layer. It relates to a weather spreading device.

A technique for forming a sub-micron fine resist pattern according to high integration of semiconductor devices, that is, by coating a photoresist on a wafer substrate, and then irradiating ultraviolet rays, electron beams, or X-rays, etc. to selectively expose the photoresist layer Lithography techniques that form patterns by exposing and then developing are still being developed, but as the megabit era enters, conventional monolayer resists are not suitable for forming submicron size patterns. Became clear.

The resolution of the pattern on the flat substrate formed by the single layer resist is determined by the lithographic contrast and the exposure contrast of the photoresist. In order to form a high resolution submicron pattern, an excellent exposure machine must be used with a high contrast resist. In this case, differences in the exposure amount depending on the thickness of the resist due to light absorption of the resist material, inherent problems of optical lithography such as reflection from the substrate, scattering of light, and the like are factors that lower the resolution.

In addition to the resolution problem, the masking characteristics require thermal stability and resistance to dry etching, and the thickness of the resist needs to be at least 1 μm.

In order to solve the above problems, multilayered resists have been proposed and very good results can be obtained as a three-layer structure.

However, in addition to the disadvantages of such a complicated process, the multilayer system is not only susceptible to stresses of the film and intermediate layers during the baking process, but also to forming a thin, uniform and pinhole-free coating on the resist.

Finally, the DESIRE method (Diffusion Enhanced Silylated Resist Process), which combines the functionality of a multilayer structure with the simplicity of a single layer structure, has been proposed (F. Coopmans and B. Roland, Solid State Technology, June 1987. pp 93-99). This has become a very desirable solution.

Silylation refers to the introduction of a silicon-containing gas or liquid silicon, such as hexamethyldisilazane (HMDS) or SiCl ₄ at high temperatures. The silylating agent reacts with the -OH group of the resin to convert it into the form of -Ph-O-Si- (Me) ₂ H. This reaction can be confirmed using FT-IR. In other words, the feature of the DESIRE method is that the optical image is converted into a silicon image through highly selective sillation from the gas phase.

This silicon image forms an embossed image by dry etching in oxygen.

In the case where the photoresist pattern is to be formed by the DESIRE method, the photoresist used should contain a reactive group such as -OH group in the molecule. In the silylation process, the reactive group reacts with the silylating agent to selectively form a silylated resist layer on the surface portion of the resist layer, and the silylated resist layer is dry-etched using O ₂ plasma or When forming a photoresist pattern by the wet developing method, it serves as an etching mask. In the case of forming a photoresist pattern without using a conventional silylation process, it is preferable to form a resist pattern using a photoresist composed of a single resin because the development process can be performed constantly. However, according to the DESIRE method, since the silylation reaction process is performed before the development process, it is necessary to optimize the silylation process by adjusting the silylation reaction.

By using the above-described DESIRE method, a fine size pattern can be obtained, but since the silylation reaction is carried out in the gas phase, it is difficult to control the reaction, so that it is difficult to form a silylated layer uniformly on the surface portion of the resist. As the width of the film is further reduced, resist residues are formed by unwanted parasitic exposure around the pattern due to diffraction of light. Furthermore, since molecular particles of the silylating agent penetrate into the resist layer and react by the silylation reaction, it is also difficult to form a predetermined pattern due to the swelling phenomenon, and adjustment of the strip process of the resist is also very difficult.

In the silylation diffusion process, which is the most important process in the imaging process, a diffusion mechanism using a gas phase coating method is used.

1 shows a schematic structure of a conventional silylation vapor phase coating apparatus, which is composed of a top plate 3 and a bottom plate 4.

By placing the wafer 6 on the lower plate 4 and injecting silylating agents such as TMOS (tetramethyldisilazane) and HMDS (hexamethyldisilazane) in the gaseous state through the coating gas inlet 1 on the upper plate. It is applied to the wafer through the filter 2 which is about 1 cm below. 2 shows a cross-sectional view of a conventional filter, where (a) is a radial filter and (b) is a mesh filter. When the silylating agent is injected through these filters, the silylating agent has a temperature of about 80 to 100 ° C. and a pressure of 0.05 kg / cm 2 or more. As a relatively large amount of gas passes through, the silylated concentration on the wafer becomes higher in the central portion than in the surroundings. Thus, the use of a filter without a through hole in the center portion as shown in FIG. 2 (a) may result in a slight thinning of the thickness of the middle portion, and in the case of the use of a mesh filter as shown in FIG. The phenomenon that the reaction is concentrated in the center is more serious because there is more amount of the coating gas passing through the center than in the case of FIG. 2 (a).

When the conventional filter is used as described above, the concentration of the coating gas is increased at the center of the wafer, and the concentration of the coating gas is lowered as the pressure of the gas decreases toward the periphery thereof, so that the uniformity of the silylated film is severely damaged.

This eventually becomes a fatal factor that degrades the resolution of the pattern obtained through the etching process.

An object of the present invention is to improve the uniformity problem of the silylated film as described above, adopts a novel filter designed to provide a silyl film having a substantially constant film thickness in the center and the peripheral portion, the structure of the gas inlet is changed It is to provide a vapor phase coating apparatus for sillation.

According to the present invention for achieving the above object, a vapor phase coating apparatus includes a lower plate on which a wafer on which a pattern is to be formed is disposed, an upper plate having a coating gas injection hole in a central portion thereof, and an upper plate disposed between the lower plate and the upper plate. In the vapor phase coating apparatus comprising a filter, a plurality of through holes are regularly arranged in a matrix form in an area excluding a certain area in the center, and the through holes are arranged in a vertical narrow light inclined 20 to 80 degrees from a horizontal plane. It is characterized by the fact that it is in the form of 上 狹 下 廣).

Preferably, the upper portion of each of the through-holes is provided with a peripheral wall extending in a cylindrical upward direction, wherein the coating gas inlet of the upper plate is higher than the highest portion of the upwardly extending peripheral wall of the upper portion of the filter through-hole. It is not located high.

The vapor phase coating device may further include a film of the same type or different types of the filter above or below the filter.

Further, the distance between the filter end portion of the coating gas injection port and the bottom of the filter upper portion is better.

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

3 is a view showing the schematic structure of the gas phase spreading apparatus of the present invention, and FIG. 4 is a cross-sectional view showing the filter structure employed in the gas phase spreading apparatus of the present invention, where (a) is a partially enlarged longitudinal sectional view of the filter and (b) is Cross section showing the overall appearance.

The filter 2 is formed of a regular matrix through-hole, so that the gas is evenly spread between the edges from the center portion into which the gas is injected and passes through the filter 2. Therefore, it is possible to obtain a higher degree of uniformity of the silylated film than using a conventional radial or mesh type filter.

In particular, as a preferred embodiment of the present invention, the filter employed in the gas phase application apparatus according to the present invention has the upper peripheral wall 8 of the through hole erected upward so that the gas directly contacts the wafer 6 during gas injection. This is prevented and is applied firstly in the space between the top plate 3 and the filter 2 and then evenly applied to the entire through-hole in the filter 2. In addition, since the lower portion 10 of the through hole is also inclined at about 20 ° to 80 °, the gas passing through the through hole can easily spread around. (The arrow 5 in the figure indicates the traveling direction of the injection gas). In order to prevent the injection gas from being concentrated to the center, the central part of the filter has a portion 9 which does not penetrate through holes in an area about 1 to 5 times the diameter of the injection hole. This central portion is to be formed in a polygonal structure, such as a circle or square, rhombus.

The size of the filter through hole is adjusted according to the gas injection pressure, but preferably, the diameter at the top thereof is adjusted to about 0.5 to 4 mm, more preferably about 1 to 3 mm.

The gas phase application device of the present invention employs the above-described filter. Preferably, the gas inlet 1 is extended so that the end 7 is almost in close contact with the filter as compared with the conventional device shown in FIG. The injected air was not injected directly into the upper portion of the photosensitive resin layer but hit the filter to allow convection in the apparatus. Thus, once the injected air is convection in the apparatus, it is possible to prevent the injection gas from being applied to the upper portion of the photosensitive resin, particularly the central portion, in a large amount, thereby improving the uniformity of the silylated film.

In the resist pattern formation, a photoresist composition made of a novolac resin, a polyvinyl hexanol resin, or the like is first formed on a semiconductor wafer in accordance with a conventional method to form a resist layer, and then selectively exposed the resist layer using a photomask. And selectively silylating the exposed resist layer to form a silylated resist layer on a surface portion of the resist layer, and then removing the unsilified resist except for the resist under the silylated resist layer. It is composed. The silylation process may be performed by a negative tone method in which the exposed portions of the resist layer are selectively silylated, or may be performed by a positive tone method in which the unexposed portions of the resist layer are selectively silylated. .

As the silylating agent that can be used in the present invention, conventionally used silylating agents can be used without exception, and examples thereof include nuxamethyldisilazane, tetramethyldisilazane, dimethylsilylamine, dimethylsilyldiethylamine, and trimethylsilyl. Dimethylamine, trimethylsilyldiethylamine, dimethylaminotrimethylsilane and the like.

Hereinafter, a preferred embodiment of the present invention will be described in detail in comparison with a method for forming a silylated film using a conventional apparatus.

The conventional vapor coating apparatus for comparison uses Japan Synthetic Rubber Co. LTD. (Plasmask-Si) equipment of Japan, and the radial and (d) shown in FIG. The micro-mesh type filter shown in Fig. 2 was employed. TMDS was used as the silylating agent, and sprayed at 90 ° C. at a pressure of 0.15 kg / cm 2 to carry out the silylation process.

The preferred filter employed in the vapor phase coating apparatus of the present invention was manufactured as follows.

Through-holes were formed in a regular mesh structure (matrix type) in the filter, and the inclination angle of the bottom of the through-holes was 50 ° from the horizontal plane, and the top of the through-holes was formed to extend upward in a cylinder of 2 mm or more in height.

The size of the through hole was 2 mm in diameter at the top, and the gap between the through holes was 0.5 mm. The part without the through hole in the center was square and the length of one side was 2 cm.

The produced filter was adopted for the coating device. At this time, the gas inlet was brought into close contact with the filter so that the distance between the end of the gas inlet and the bottom of the upper filter was about 1 mm. The tetramethyl disilazane (TMDS), a silylating agent, was vapor-coated at a pressure of 0.15 kg / cm 2 at 90 ° C.

5 is a graph showing the state of the silylation film obtained after performing the silylation process using the three filters. In the graph, (a) shows a case of using a vapor phase coating apparatus employing a conventional radial filter (b), and (c) shows a case of using a vapor phase coating apparatus employing a conventional mesh filter (d). The conditions of the membranes obtained in the case of using a vapor phase coating apparatus employing a regular mesh filter (f) are described. In the graph, the solid line (-) indicates the state in which the photosensitive resin film is formed before forming the silylated film, and the dotted line (---) indicates the film thickness after the silylated film is formed.

As a result, the difference between the solid line and the dotted line value is the thickness of the silylated film.

As can be seen from the graph, it can be seen that the film obtained by performing the silylation using a conventional gas phase coating apparatus employing a radial filter becomes thicker and uneven toward the center of the wafer. In the case of using a mesh filter, the thickness difference between the center portion and the edge is more severe, so that the film thickness at the edge portion is not uniform.

However, the silylated film obtained by using the gas phase coating apparatus in the present invention has almost no thickness difference between the center and the edge, and it can be confirmed that the film thickness is formed evenly.

The above effects can be obtained by using the matrix type filter according to the present invention, because the injection gas is first applied to the upper part of the wafer uniformly at the center part and the edge part of the filter, so that only the central part is silly concentrated. Because it is prevented. In addition, the peripheral wall extending to the upper part of the filter through hole prevents the injection gas from being applied directly to the upper part of the resin layer, and since the lower part of the through hole is inclined in the form of a light narrowing light, the gas passing through the through hole to the upper part of the resin layer Because it can be easily expanded. Moreover, the device of the present invention has a long gas injection port so that the injected gas hits the filter once and convections between the device top plate and the filter, thereby preventing the injection gas from being directly applied to the wafer.

In conclusion, when the silylation process is performed using the vapor phase coating apparatus according to the present invention, a film having a high uniformity is formed, which provides a pattern having excellent resolution through a subsequent etching process. That is, since the problem of uniformity, which is one of the biggest problems of the silylation process, which is the most important process in the image process by the DESIRE method, can be solved according to the present invention, its use value may be very large.

In addition to the above embodiments disclosed in the present invention, it should be understood that the matrix filter of the present invention can be applied without exception in all cases without departing from the scope of the claims of the present invention.

Claims (4)

In the vapor phase coating apparatus comprising a lower plate on which a wafer on which a pattern is to be formed is disposed, an upper plate having a coating gas injection hole at a central portion thereof, and a filter disposed at an upper portion of the wafer between the lower plate and the upper plate. The filter has a plurality of through holes arranged regularly in a matrix form in an area excluding a certain area in the center, and the through holes are in the form of upper and lower light inclined 20 to 80 degrees from a horizontal plane. Vapor phase coating apparatus. 2. The vapor phase coating apparatus according to claim 1, wherein a peripheral wall extending in a cylindrical shape is provided on the upper portion of each of the through holes. 3. The vapor phase coating apparatus according to claim 2, wherein the coating gas inlet of the upper plate is located not higher than the highest portion of the upwardly extending peripheral wall above the filter through hole. The vapor phase coating apparatus according to claim 1, wherein the vapor phase coating apparatus further comprises a film of the same type or different type as the filter above or below the filter.