JP2007063637A - Method for producing organic thin film, and optical cvd system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for depositing an organic thin film capable of depositing an organic thin film of high quality without causing unintended side reaction, and to provide an optical CVD (Chemical Vapor Deposition) system. <P>SOLUTION: A raw material monomer 21 and a photosensitizer 22 are fed to a film deposition chamber 11 whose pressure is reduced to a prescribed vacuum degree, and the polymerization reaction of the raw material monomer 21 is caused via the photosensitizer 22 excited by the light of a light source 15, thus the polymerized film is deposited on a substrate W. Since the light source 15 is arranged so as to face only to an introduction flow passage 26 for the photosensitizer 22, the light of the light source 15 is not emitted to the raw material monomer 21 and the substrate W in the film deposition chamber. In this way, the generation of unintended side reaction (cutting reaction and cross-linking reaction) by the light irradiation of the light source 15 on the raw material monomer 21 or the high polymer film on the substrate W can be effectively prevented, and an organic thin film, e.g., with a three-dimensional structure can be deposited at high quality and high precision. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an organic thin film manufacturing method and a photo CVD apparatus capable of forming an organic polymer film on a substrate with high accuracy using a photo CVD (Chemical Vapor Deposition) method.

  In recent years, allyl diglycol carbonate (or diethylene glycol diallyl carbonate) is known as a very sensitive plastic for detecting radiation tracks. Allyl diglycol carbonate is a polymer material having a three-dimensional structure. It is expected that a highly sensitive resist for charged particles can be obtained by thinning this material with high accuracy.

  Conventionally, when an organic thin film is applied and formed on a semiconductor wafer or a glass substrate, a spin coat method, a spray method or the like has been widely used. However, since a polymer material having a three-dimensional structure such as allyl diglycol carbonate is insoluble in a solvent, it is very difficult to form a thin film by using a method of liquefying and coating on a substrate.

  On the other hand, a technique for forming an inorganic or organic thin film on a substrate by a photo-CVD method is known (see, for example, Patent Documents 1 and 2 below). The photo-CVD method is a process technology that decomposes gas molecules with light energy and forms a thin film on a substrate at a low temperature. According to this photo-CVD method, since a film can be formed directly from a gas phase, a thin film of a polymer material having a three-dimensional structure insoluble in a solvent can be formed.

JP-A-5-175135 Japanese Patent Laid-Open No. 6-279991

  However, in the conventional photo-CVD method, the polymer material deposited on the substrate is also irradiated with light from the light source. Therefore, a side reaction (unintentional cutting reaction or There is a problem that a crosslinking reaction occurs. Therefore, in the conventional photo-CVD method, even if a polymer film having a three-dimensional structure can be formed, variations in film quality and deterioration of characteristics cannot be avoided.

  This invention is made | formed in view of the above-mentioned problem, and makes it a subject to provide the organic thin film formation method and photo-CVD apparatus which can form a good-quality organic thin film accurately, without producing unintended side reaction.

  In solving the above problems, an organic thin film forming method of the present invention is an organic thin film manufacturing method in which an organic thin film is formed on a substrate placed in a vacuum chamber. A step of introducing a sensitizer, a step of activating the photosensitizer by light irradiation, a step of polymerizing raw organic molecules through the activated photosensitizer and depositing a polymer film on the substrate, It is characterized by having.

  In the present invention, a polymerization reaction of raw organic molecules is caused by a photosensitizer activated and excited by light irradiation, and a polymer film of the raw organic molecules is formed on a substrate. Select light in the wavelength region that does not cause reaction to the raw organic molecules as excitation light for the photosensitizer, or install a light source at a site where the organic raw material molecules are not affected, such as on the route of introduction of the photosensitizer. Thus, side reactions due to excitation light of the organic thin film formed on the substrate can be prevented, and a high-quality polymer film can be formed with high accuracy.

  The photosensitizer is not particularly limited as long as it can cause the polymerization reaction of the raw organic molecules by the absorption of excitation light. When the excitation light is ultraviolet light, mercury can be used as a photosensitizer, but organic materials such as benzophenone and benzoin isobutyl ether can be preferably used. Moreover, an ultraviolet lamp, an ultraviolet laser, etc. are used for an excitation light source.

  The starting organic molecule is a monomer or oligomer having one or two or more polymerizable reactive groups in one molecule. In the case of an organic molecule having only one polymerizable reactive group in one molecule (for example, styrene, methyl methacrylate, ethyl acrylate, etc.), a linear polymer film is formed on the substrate. On the other hand, in the case of an organic molecule having two or more polymerizable reactive groups in one molecule (for example, allyl diglycol carbonate), a polymer film having a three-dimensional structure is formed on the substrate.

  When raw organic molecules that do not directly react when irradiated with light that activates the photosensitizer are used, even if an excitation light source for the photosensitizer is installed in the film forming chamber in the vacuum chamber I do not care. On the other hand, when raw material organic molecules that are likely to cause a reaction upon irradiation with light from the excitation light source are used, the excitation light source may be provided at a site isolated from the raw material organic molecules.

  The photo-CVD apparatus according to the present invention is preferably implemented in the latter example. That is, the photo-CVD apparatus of the present invention includes a vacuum chamber, a stage for supporting a substrate in the vacuum chamber, a raw organic molecule introduction system for introducing raw organic molecules into the vacuum chamber, and a photosensitizer into the vacuum chamber. A photosensitizer introduction system for introducing a photosensitizer and a light source for irradiating light that activates the photosensitizer, the light source being installed facing the photosensitizer introduction system, .

  With this configuration, the photosensitizer is activated by being irradiated with light from the excitation light source while being introduced into the vacuum chamber. In this case, since the excitation light source does not exist in the film formation chamber, the raw material organic molecules introduced into the film formation chamber do not react with the irradiation light from the excitation light source. Thereby, for example, a polymer film having a three-dimensional structure can be formed with good quality and high accuracy without causing side reactions.

  As described above, according to the present invention, a high-quality organic thin film having a linear structure or a three-dimensional structure can be formed on a substrate with high accuracy.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, this invention is not limited to these, A various deformation | transformation is possible based on the technical idea of this invention.

(First embodiment)
FIG. 1 is a schematic configuration diagram of an organic thin film manufacturing apparatus (photo CVD apparatus) 1 for explaining an organic thin film manufacturing method according to the present invention. The illustrated organic thin film manufacturing apparatus 1 includes a vacuum chamber 12 in which a film forming chamber 11 is formed. A stage 13 that supports the substrate W is installed at the bottom of the film forming chamber 11. A flow path 14 through which a coolant such as cooling water circulates is formed inside the stage 13, thereby enabling the stage 13 to be maintained at a predetermined low temperature.

  A low-pressure mercury lamp is installed as a light source 15 on the upper portion of the vacuum chamber 12. The light source 15 mainly emits ultraviolet light having a wavelength of 253.7 nm. The light source 15 is disposed so as to irradiate the substrate W placed on the stage 13 through the window member 16 that covers the upper part of the film forming chamber 11. The window member 16 is made of a transparent glass material such as quartz.

  The light source 15 is installed outside the vacuum chamber 12 and has an atmospheric pressure of atmospheric pressure, but the atmosphere is replaced with nitrogen gas for the purpose of preventing attenuation of light intensity due to oxygen.

  The film forming chamber 11 is depressurized to a predetermined pressure via the exhaust pipe 17. The exhaust pipe 17 communicates with a vacuum exhaust means such as a vacuum pump (not shown).

  On the other hand, a mixed gas of the raw material monomer 21 and the photosensitizer 22 is introduced into the film forming chamber 11 through the gas supply pipe 20 and the nozzle 20 ′. A raw material organic molecule introduction line 18 and a photosensitizer introduction line 19 are connected to the gas supply pipe 20. The raw material monomer 21 and the photosensitizer 22 are stored in the tanks 21A and 22A in a liquefied state, heated to a predetermined temperature by the heaters 21B and 22B, and vaporized by a bubbling action using argon gas (carrier gas).

  The raw material monomer 21 is a raw material of an organic thin film formed on the substrate W, and a polymerization reaction occurs in the film forming chamber 11 by the excitation action of the photosensitizer 22 and is deposited on the substrate W. The raw material monomer 21 is an organic molecule having one or two or more polymerizable reactive groups (for example, a vinyl group) in one molecule. In this embodiment, an organic molecule having two polymerizable reactive groups in one molecule is applied, and specifically, an allyl diglycol carbonate monomer material whose molecular structure is three-dimensional by a polymerization reaction is used. It has been. Allyl diglycol carbonate is a material that does not easily react directly with light from the light source 15.

  The photosensitizer 22 is made of a material that is activated by absorbing light from the light source 15 and causes a polymerization reaction of the raw material monomer 21 by its excitation action. In this embodiment, since an ultraviolet light source having a wavelength of 253.7 nm is used as the light source 15, an organic material having an absorbance peak in the wavelength region, for example, benzophenone or benzoin isobutyl ether as shown in FIG. (Benzoin Isobuthyl Ether) is preferred.

  In addition, although mercury can also be applied as the photosensitizer 22, the above-described organic materials are most preferable from the viewpoint of metal contamination of the formed film and reduction of environmental burden. The organic photosensitizer described above is also excellent in terms of chemical stability and ease of introduction into the film forming chamber 11 (melting point and boiling point).

  In the organic thin film manufacturing apparatus 1 configured as described above, the film forming chamber 11 is evacuated through the exhaust pipe 17 and maintained at a predetermined degree of vacuum. Moreover, in the raw material organic molecule introduction line 18 and the photosensitizer introduction line 19, gases of the raw material monomer 21 and the photosensitizer 22 are generated, respectively. The generated raw material monomer gas and photosensitizer gas are mixed in the gas supply pipe 20 and then introduced into the film forming chamber 11 through the nozzle 20 ′.

  The film forming chamber 11 is irradiated with light from the light source 15. Accordingly, the photosensitizer 22 introduced into the film forming chamber 11 absorbs light from the light source 15 and is activated (excited). Polymerization of the raw material monomer 21 is started via the activated photosensitizer 22, and the polymerized molecules are deposited on the substrate W. Thereby, an allyl diglycol carbonate film having a three-dimensional structure is formed on the substrate W.

  In the present embodiment, the polymerization reaction of the raw material monomer 21 is caused not by direct irradiation from the light source 15 but by the excitation action of the photosensitizer 22 that absorbs the irradiation light from the light source 15. In the polymer polymer film formed on the substrate W, side reactions (unintentional reactions) can be prevented from occurring due to light from the light source 15. Thereby, it is possible to form a high-quality polymer film having a three-dimensional structure with a polymerizable reactive group as a base point with high accuracy.

  The deposition rate of the polymer film on the substrate W can be controlled by the temperature of the stage 13 that supports the substrate W. FIG. 3 shows the relationship between the stage temperature and the film formation rate when the degree of vacuum is 1.0 Torr.

  As shown in FIG. 3, it can be seen that the film formation rate rapidly decreases as the stage temperature increases. This is presumably because the amount of monomer physically adsorbed on the substrate surface decreases rapidly with increasing temperature. Therefore, it can be considered that the active species generated in the gas phase are first adsorbed on the substrate to become a starting point, and then the film formation proceeds so that the polymerization reaction is promoted by receiving the monomer supply from the gas phase. The polymerization termination reaction can be considered when radicals formed in the gas phase are coupled with growth ends on the substrate and when growth ends are coupled on the substrate.

In addition, the film formation rate varies greatly depending on the intensity of the light source, the molecular weight of the raw material monomer, and the atmospheric pressure in the film formation chamber. FIG. 4 shows the experimental results of measuring the film formation rate of various raw material monomers under a predetermined pressure. The photosensitizer is benzophenone (70 ° C., carrier argon flow rate is 438 sccm), the film forming chamber pressure is 0.5 to 3.0 Torr, the stage temperature is 20 ° C., the monomer temperature and the carrier argon flow rate are each room temperature to 60 C., 100 sccm, and the film formation time was 20 minutes. At this time, a low-pressure mercury lamp was used as the light source, and the lamp intensity was 15 to 20 mW / cm ² .

  As shown in FIG. 4, it can be seen that the higher the molecular weight, the higher the deposition rate. Further, it was found that when the film forming pressure was made higher than the pressure shown in FIG. 4, a very soft oily film was formed. The maximum film formation rate obtained in this experimental system was about 1270 K / min when diethylene glycol dimethacrylate was used.

(Second Embodiment)
FIG. 5 shows a second embodiment of the present invention. In the figure, parts corresponding to those of the first embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the organic thin film forming apparatus (photo CVD apparatus) 2 of the present embodiment, the outlet end of the gas supply pipe 20 that supplies the mixed gas of the raw material monomer 21 and the photosensitizer 22 is connected to the upper wall portion of the vacuum chamber 12. The mixed gas is introduced into the film forming chamber 11 through a perforated plate 23 disposed between the stage 13 and the window member 16. The perforated plate 23 is formed of a quartz plate having excellent light transmittance.

  With this configuration, the mixed gas of the raw material monomer 21 and the photosensitizer 22 is introduced into the film forming chamber 11 in a downflow state and is uniformly supplied onto the substrate W. Therefore, the organic thin film formed on the surface of the substrate W It is possible to improve the in-plane uniformity of the film thickness.

(Third embodiment)
6A and 6B show a third embodiment of the present invention. In the figure, portions corresponding to those of the first embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the organic thin film forming apparatus (photo CVD apparatus) shown in FIG. 6A, a gas supply block 24 is attached to one side wall portion of the vacuum chamber 12. In the gas supply block 24, a flow path (raw material organic molecule introduction system) 25 through which the raw material monomer 21 flows and a flow path (photo sensitizer introduction system) 26 through which the photosensitizer 22 flows are formed, respectively. The raw material monomer 21 and the photosensitizer 22 are independently supplied to the film forming chamber 11.

  The light source 15 for exciting the photosensitizer 22 is provided in the gas supply block 24. The gas supply block 24 is made of a non-translucent material such as aluminum or stainless steel. The light source 15 faces the flow path 26 through which the photosensitizer 22 flows, and is installed through a quartz window member 16, and light from the light source 15 flows through the flow path 25 of the raw material monomer 21 and the film forming chamber 11. It is configured so that only the photosensitizer 22 is irradiated.

  In the photo-CVD apparatus of the present embodiment configured as described above, the photosensitizer 22 is activated by being irradiated with light from the light source 15 along the introduction path introduced into the film forming chamber 11. . The activated photosensitizer 22 is mixed with the raw material organic molecules 21 in the film forming chamber 11 to cause polymerization of the raw material monomer 21. Thereby, a polymer film of the raw material monomer 21 is formed on the substrate W.

  According to the present embodiment, the excitation light source 15 for the photosensitizer 22 is installed in the gas supply block 24 and the photosensitizer 22 is irradiated with excitation light on the introduction path to the film forming chamber 11. Therefore, the raw material monomer 21 and the substrate on the stage 13 do not receive light from the light source 15. Therefore, in the film forming chamber 11, the organic thin film formed on the raw material monomer 21 and the substrate W does not cause an unintended side reaction by the light of the excitation light source, and a high-quality organic thin film can be formed with high accuracy. It becomes.

  In particular, according to the present embodiment, it is suitable when using a raw material monomer that undergoes a direct reaction upon receiving light from the light source 15 without a photosensitizer. Of course, even if it is not such a raw material monomer, the generation of unintended side reactions on the substrate can be avoided, so that a high-quality organic thin film can be formed with high accuracy.

  In the apparatus configuration example shown in FIG. 6A, each flow path of the gas supply block 24 is arranged so that the inflow path of the raw material monomer 21 in the film forming chamber 11 is closer to the substrate than the inflow path of the photosensitizer 22. 25 and 26 are configured. Instead of introducing the photosensitizer 22 so that the inflow path of the photosensitizer 22 is closer to the substrate than the inflow path of the raw material monomer 21, as shown in FIG. The flow path 26 may be provided at a position lower than the introduction flow path 25 of the raw material monomer 21.

  6B enables the photosensitizer 22 to be supplied in the vicinity of the substrate W, so that the polymer film on the substrate W is simultaneously formed with the polymerization reaction of the raw material monomer 21 in the gas phase. It is possible to accelerate the polymerization reaction, and a high film formation rate can be obtained.

It is a schematic block diagram of the organic thin film forming apparatus explaining the 1st Embodiment of this invention. It is an absorption spectrum figure of the benzophenone and benzoin isobutyl ether used as a photosensitizer. It is a figure which shows the relationship between stage temperature and the film-forming speed | rate. It is a figure which shows an example of the kind of raw material monomer, and the experimental result of the film-forming speed | rate. It is a schematic block diagram of the organic thin film forming apparatus explaining the 2nd Embodiment of this invention. Both A and B are schematic block diagrams of an organic thin film forming apparatus for explaining a third embodiment of the present invention.

Explanation of symbols

1,2,3 Organic thin film forming equipment (photo CVD equipment)
DESCRIPTION OF SYMBOLS 11 Deposition chamber 12 Vacuum chamber 13 Stage 15 Light source 16 Window member 17 Exhaust pipe 18 Raw material organic molecule introduction line 19 Photosensitizer introduction line 20 Gas supply pipe 21 Raw material monomer 22 Photosensitizer 23 Perforated plate W substrate

Claims (6)

An organic thin film manufacturing method for forming an organic thin film on a substrate installed in a vacuum chamber,
Introducing raw organic molecules and a photosensitizer into the vacuum chamber;
Activating the photosensitizer by light irradiation;
And a step of polymerizing the raw organic molecules through the activated photosensitizer to deposit a polymer film on the substrate.   2. The method for producing an organic thin film according to claim 1, wherein the photosensitizer is activated by being irradiated with light in an introduction path introduced into the vacuum chamber.   2. The organic thin film manufacturing method according to claim 1, wherein the raw organic molecules are organic molecules having one or more polymerizable reactive groups in one molecule.   2. The organic thin film manufacturing method according to claim 1, wherein the photosensitizer is an organic material having a light absorption property in an ultraviolet region. A vacuum chamber, a stage for supporting a substrate in the vacuum chamber, a raw organic molecule introduction system for introducing raw organic molecules into the vacuum chamber, and a photosensitizer introduction for introducing a photosensitizer into the vacuum chamber A system and a light source that emits light that activates the photosensitizer,
The photo-CVD apparatus, wherein the light source is installed facing the photosensitizer introduction system. The photo-CVD apparatus according to claim 5, wherein the stage includes a substrate cooling mechanism that cools the substrate.

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