JP5246933B2 - Film forming apparatus and film forming method - Google Patents

Description

  The present invention relates to a film forming apparatus and a film forming method.

  Conventionally, as a method for forming an organic thin film, a wet method, a vapor deposition polymerization method, or the like is used. Among these methods, the wet method is a method in which a raw material monomer is dissolved in a suitable solvent, polymerized, and applied onto a substrate. The vapor deposition polymerization method is a method in which raw material monomers are evaporated, introduced into a vacuum processing chamber, polymerized on the surface of a substrate to form a polymer film, and can be formed without using a solvent. This has the advantage that the film is smoothly attached to the surface. As an apparatus used for such a vapor deposition polymerization method, in the vapor deposition polymerization apparatus that evaporates the raw material monomer supplied to the evaporation source container in a vacuum by a heating means, the heating means is provided in the evaporation source storage part of the evaporation source container. The first heating means provided and the second heating means provided at the evaporation source outlet, the heating temperature of the second heating means being set slightly higher than the heating temperature of the first heating means Is known (see, for example, Patent Document 1).

JP-A-5-65627 (Claim 1, FIG. 1, etc.)

  In such a vapor deposition polymerization apparatus, the raw material monomer is heated to bring the inside of the evaporation source into a saturated vapor pressure state, and the evaporation gas is utilized by utilizing the pressure difference between the inside of the evaporation source (saturated vapor pressure state) and the film forming chamber (low vacuum state). Is allowed to flow from the evaporation source into the film formation chamber and polymerized on the substrate to form a polymer film having a stoichiometric ratio. Therefore, in the vapor deposition polymerization apparatus, the film formation rate depends on the pressure difference between the evaporation source and the film formation chamber, that is, depends on the heating temperature for setting the saturation vapor pressure of the evaporation source.

  However, if the film formation is repeated with a constant heating temperature set to a constant film formation rate, the raw material monomers are decomposed or self-polymerized by heating and oligomerized over time. As a result, the saturated vapor pressure in the evaporation source decreases, and as a result, the pressure difference between the evaporation source and the film formation chamber decreases, and the film formation rate may decrease. In the case of film formation using two raw material monomers, when only one of the raw material monomers is altered and the saturated vapor pressure decreases and the film formation rate decreases, a polymer film having a desired stoichiometric ratio cannot be formed. There is a problem that there is.

  In this case, even if an attempt is made to increase the saturated vapor pressure by heating the raw material monomer at a higher temperature in order to restore the lowered film formation rate, the original film formation rate is suddenly returned to the original film formation rate due to the high heat capacity of the raw material monomer. I can't.

  Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art, and the supply rate of the evaporative gas flowing into the film forming chamber is controlled to keep the film forming rate constant, and the high quality and high quality. An object of the present invention is to provide a film forming apparatus capable of stably forming a molecular film and a film forming method therefor.

The film forming apparatus of the present invention includes a vacuum film forming chamber in which a film forming target is installed, an evaporation source in which a raw material monomer is sealed, and a heating unit provided in the evaporation source. A film forming apparatus for forming a film by introducing an evaporation gas obtained by heating and evaporating a raw material monomer into the vacuum film forming chamber and performing vapor deposition polymerization on the surface of the film forming target, The raw material pipe connected to the evaporation source is provided with a conductance variable valve and a pressure gauge, and the conductance variable valve has a pressure value measured by the pressure gauge equal to a set pressure value of the conductance variable valve. a control unit for controlling the opening of the conductance variable valve provided to the control unit is also connected to the heating means, the control unit, the opening degree of the variable conductance valve is a predetermined value If it becomes is characterized by being configured to the heating temperature of the raw material monomer is increased a predetermined value by the heating means.

In the film forming apparatus of the present invention, the conductance variable valve, the pressure gauge, and the control unit are provided, and the conductance thereof is set so that the pressure value measured by the pressure gauge becomes equal to the pressure value set by the conductance variable valve. Can be controlled, and the supply amount of the evaporation gas can be controlled to be constant. Further, the control unit is configured to increase the heating temperature of the raw material monomer by the heating means by a predetermined value, so that when the opening of the conductance variable valve becomes a predetermined value, the saturated vapor pressure is reduced. Can be raised to ensure pressure.

  Here, the pressure gauge is preferably provided between the conductance variable valve of the raw material pipe and the vacuum film forming chamber. This is because the raw material monomer hardly adheres to the pressure gauge by providing the pressure gauge at such a position.

  Two evaporation sources are provided for one vacuum film forming chamber, and the conductance variable valve and the pressure are connected to the material pipe connected to at least one of the two evaporation sources. A meter is preferably provided. When performing vapor deposition polymerization of two or more elements, the conductance variable valve and the pressure gauge are provided in at least one of the raw material pipes, so that the apparatus can be configured more easily and at a reduced cost. Is possible.

The film forming method of the present invention is a film forming method in which an evaporation gas obtained by heating and evaporating a raw material monomer in an evaporation source is introduced into a vacuum film forming chamber and vapor-deposited and polymerized on the surface of the film forming target. A pressure value measured by a pressure gauge provided in a raw material pipe connecting the vacuum film forming chamber and the evaporation source, and a set pressure value of a conductance variable valve provided in the raw material pipe. The opening of the conductance variable valve is adjusted to be equal, and when the opening of the conductance variable valve reaches a predetermined value, the heating temperature of the raw material monomer is increased by a predetermined value by the heating means. . By adjusting the opening of the conductance variable valve, it is possible to keep the supply amount of the evaporation gas supplied from the film formation chamber to the evaporation source constant. Further, when the opening degree of the conductance variable valve reaches a predetermined value in this way, the opening degree of the variable conductance valve becomes 100% by increasing the heating temperature of the raw material monomer in advance by a predetermined value. Since the saturated vapor pressure itself can be raised in advance, it is possible to keep the vapor supply amount constant.

  In a preferred embodiment of the present invention, 1,12-diaminododecane and 1,3-bis (isocyanatomethyl) cyclohexane as the raw material monomers are sealed in separate evaporation sources, respectively. At least the 1,3-bis (isocyanatomethyl) cyclohexane is used for introducing the evaporated gas obtained by evaporation into the vacuum film forming chamber and depositing it on the surface of the film forming and simultaneously polymerizing the film. Adjusting the opening of the conductance variable valve provided in the raw material pipe connected to the evaporation source.

  According to the film forming apparatus of the present invention, since the supply amount of the evaporative gas flowing into the vacuum film forming chamber can be controlled and kept constant, the film forming rate is kept constant and the high-quality polymer is maintained. There is an excellent effect that the film can be stably formed. Further, according to the film forming method of the present invention, the supply amount of the evaporative gas flowing into the vacuum film forming chamber can be controlled and kept constant, so that the film forming rate is kept constant and high quality is achieved. There is an excellent effect that the polymer film can be stably formed.

  The film forming apparatus of this embodiment will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view of a film forming apparatus.

  The film forming apparatus 1 has a film forming chamber 10 in which a substrate S to be formed is placed. The film forming chamber 10 is provided with a vacuum exhaust means 11 so that the inside of the film forming chamber 10 can be set to a desired degree of vacuum (-10 Pa). The film forming chamber 10 is provided with source gas supply means 20a and 20b via a mixing chamber 12 provided at a position facing the substrate S. A shower plate 13 is installed inside the mixing chamber 12.

  The raw material gas supply means 20a, 20b includes evaporation sources (evaporation source containers) 21a, 21b in which different raw material monomers Ma, Mb are sealed. The source gas supply means 20a and 20b are provided with heating means 22a and 22b, and the heating means 22a and 22b heat different source monomers Ma and Mb in the evaporation sources 21a and 21b at a desired temperature. It is configured to be able to. In this embodiment, two evaporation sources are provided, but at least one evaporation source may be provided.

  The evaporation sources 21a and 21b are connected to the mixing chamber 12 described above via pipes 23a and 23b provided with supply amount control means 30a and 30b. The supply amount control means 30a and 30b are for controlling the flow rate of the evaporation gas obtained by the evaporation sources 21a and 21b to the film forming chamber 10. In this embodiment, the supply amount control means 30a and 30b are provided in this way, so that the supply amount of the evaporation gas formed by the evaporation sources 21a and 21b to the film forming chamber 10 can be controlled. Here, the supply amount control means 30a, 30b includes conductance variable valves 31a, 31b and pressure gauges 32a, 32b. The conductance variable valves 31a and 31b are configured so as to be able to change the conductance of the pipes 23a and 23b by opening and closing valves (not shown) to adjust the opening. As the supply amount control means 30a and 30b, use of conductance variable valves 31a and 31b which are heat resistant and difficult to deposit the raw material, rather than using a mass flow controller which is weak against heating and in which the raw material is likely to precipitate. Thus, the vapor deposition polymerization method can be performed more efficiently.

  Further, the adjustment of the opening degree of the conductance variable valves 31a and 31b is performed by the control units 33a and 33b provided in the conductance variable valves 31a and 31b. The control units 33a and 33b allow the conductance variable valves 31a and 31b so that the pressure values measured by the pressure gauges 32a and 32b are equal to the pressure values set by the conductance variable valves 31a and 31b (hereinafter referred to as set pressure values). The degree of opening is controlled. Further, although not shown, the control units 33a and 33b are also connected to the heating means 22a and 22b, and the control units 33a and 33b are configured such that the opening degrees of the conductance variable valves 31a and 31b become a predetermined valve opening degree. In such a case, the heating means 22a and 22b are configured to increase the heating temperature of the raw material monomers Ma and Mb by a certain value.

  In the present embodiment, the supply amount control means 30a and 30b are provided in the pipes 23a and 23b, but at least pipes connected to an evaporation source in which a raw material monomer whose saturation vapor pressure is likely to decrease due to heating is enclosed. It is sufficient if one is provided.

  In the present embodiment, the pressure gauges 32a and 32b are provided between the conductance variable valves 31a and 31b of the pipes 23a and 23b and the mixing chamber 12 because the raw material monomer adhering to the pressure gauge is small, and the pressure gauges 32a and 32b. The pressure gauges 32a and 32b only need to be provided at least at this position. Further, the pressure gauges 32a and 32b may be provided on both sides of the conductance variable valves 31a and 31b of the pipes 23a and 23b.

  The operation of the film forming apparatus 1 will be described. First, the evaporation sources 21a and 21b are heated by the heating means 22a and 22b, and the inside of the evaporation sources 21a and 21b is in a desired saturated vapor pressure state. When the conductance variable valves 31a and 31b are opened, the evaporation gas formed in the evaporation sources 21a and 21b is transferred to the mixing chamber 12 via the pipes 23a and 23b due to a pressure difference between the film forming chamber 10 and the evaporation sources 21a and 21b. Inflow. In this embodiment, the amount of evaporation gas supplied into the film forming chamber 10 is controlled to be constant by adjusting the opening of the conductance variable valves 31a and 31b by the control units 33a and 33b. Is possible. That is, in the present embodiment, even when the saturated vapor pressure decreases with the passage of the film formation time, the set pressure value of the conductance variable valves 31a and 31b and the pressure value during film formation of the pressure gauges 32a and 32b are equal. As described above, by increasing the opening of the conductance variable valves 31a and 31b by the control units 33a and 33b, the amount of evaporation gas supplied into the film forming chamber 10 can be controlled to be constant. Further, if the opening degree of the conductance variable valves 31a and 31b reaches 100%, the flow rate cannot be controlled any more. Therefore, the control units 33a and 33b have the predetermined opening degree of the conductance variable valves 31a and 31b. When the valve opening degree is reached, the heating temperature is raised by the heating means 22a and 22b to increase the saturated vapor pressure of the evaporation sources 21a and 21b to compensate the flow rate in advance, thereby enabling the flow rate control.

  The vaporized gas passes through the shower plate 13 provided in the mixing chamber 12 and is homogenized, and then flows into the film forming chamber 10 to undergo vapor deposition polymerization on the substrate S, and the chemistry of the raw material monomers Ma and Mb. An absorptive polymer film is formed.

  A film forming method using this film forming process will be described in detail with reference to FIG. FIG. 2 is a flowchart for explaining the film forming method.

  When the film forming method starts, first, in step S1, the substrate S is set in the film forming chamber 10, and in step S2, the inside of the film forming chamber 10 and the evaporation sources 21a and 21b are evacuated to a desired pressure. .

  Next, in step S3, the evaporation sources 21a and 21b are heated by the heating means 22a and 22b, and the evaporation sources 21a and 21b are brought into saturated vapor pressure states of the raw material monomers Ma and Mb, respectively. The heating temperature in this case is set to a temperature at which a desired saturated vapor pressure can be obtained. Next, in step S4, a set pressure is input to each conductance variable valve 31a, 31b. This set pressure is appropriately set in consideration of conductance, saturation vapor pressure, and the like of the pipes 23a and 23b. That is, when a necessary flow rate is set according to the composition of the polymer film and the deposition time, a necessary pressure difference between the deposition chamber 10 and the evaporation sources 21a and 21b can be obtained based on this. Since the saturated vapor pressure, the set pressure, and the like are obtained based on this pressure difference, the set pressure is input to the conductance variable valves 31a and 31b.

  After step S4 ends, in step S5, the conductance variable valves 31a and 31b are opened to a predetermined opening so as to reach the set pressure, and film formation is started.

  In step S6, pressures are measured by the pressure gauges 32a and 32b, respectively, and it is determined whether or not the pressures are smaller than the set pressures set in the conductance variable valves 31a and 31b in step S5. If larger (N), the process proceeds to step S7. If it is smaller (Y), the process proceeds to step S8. In step S8, the opening of the conductance variable valves 31a and 31b is opened at a predetermined ratio so as to be a predetermined pressure. That is, in steps S6 and S8, since the raw material monomers Ma and Mb are altered over time and the saturated vapor pressure is decreasing, the pressure is lower than the set pressure. Therefore, in order to keep the flow rate constant, the conductance variable valve 31a, The opening degree of 31b is made larger.

  Next, in step S9, it is determined whether or not the opening of the conductance variable valves 31a and 31b due to opening in step S8 exceeds a predetermined valve opening. The predetermined valve opening is set in advance. If it exceeds (Y), the process proceeds to step S10. If it falls below (N), the process proceeds to step S7. In step S10, the heating means 22a and 22b are adjusted to increase the heating temperature of the evaporation sources 21a and 21b. This is because the opening of the variable conductance valves 31a and 31b exceeds the predetermined valve opening, so that the heating temperature of the evaporation sources 21a and 21b is increased by a certain value before the opening of the valves reaches 100%. This is to keep the constant. That is, since it is difficult to keep the flow rate constant only with the heating temperature in a state where the opening degree cannot be adjusted, in steps S9 and S10, the heating temperature is increased by a certain value before the opening degree cannot be adjusted in advance. The saturated vapor pressure is raised to ensure the pressure. By connecting the control units 33a and 33b to the heating means 22a and 22b in this way, the valve opening can be controlled at all times and the flow rate can be controlled. This constant value is appropriately set depending on the composition and heat capacity of the raw material monomer, the film formation time, and the like.

  In step S7, it is determined whether the film formation time has elapsed. If it has elapsed (Y), it is determined that the film formation has ended, and the process proceeds to step S11. If not (N), the process returns to step S6.

  In step S11, since the film formation is completed, the conductance variable valves 31a and 31b are closed. In step S12, the evaporation sources 21a and 21b are opened to the atmosphere (in the film forming chamber and), and the substrate S is taken out in step S13 to complete the film forming process.

  As described above, in the film forming method according to the present embodiment, it is determined whether or not the pressure measured by the pressure gauges 32a and 32b is smaller than the set pressure by executing Step S6 and Step S8. In the case where it is small, the amount of inflow into the film forming chamber 10 can be kept constant by increasing (adjusting) the opening of the conductance variable valves 31a and 31b. Furthermore, by performing Step 9 and Step 10, that is, when the opening degree reaches a certain opening degree, the heating temperature is adjusted so that even in the case of long-time film formation, The inflow amount of can be kept constant. Hereinafter, the present invention will be described in detail by way of examples and comparative examples.

  1,12-diaminododecane as the raw material monomer Ma and 1,3-bis (isocyanatomethyl) cyclohexane as the raw material monomer Mb were sealed in the evaporation sources 21a and 21b of the film forming apparatus 1, respectively. As the conductance variable valves 31a and 31b, opening-adjustable bellows valves were used. As the pressure gauges 32a and 32b, sapphire diaphragm pressure gauges were used. Then, the pressure in the film forming chamber 10 was set to 1 Pa, the evaporation sources 21a and 21b were heated at 95 ° C. and 85 ° C., and the inside of the evaporation sources 21a and 21b was set to desired saturated vapor pressure states (24 Pa and 26 Pa), respectively. Then, the polyurea film formation was started by setting the set pressure of the conductance variable valves 31a and 31b to 3 Pa. During film formation, the valve opening was measured and the film formation rate was also measured. Further, FTIR measurement was performed on the film formation target surface to measure the film composition. These measurement results are shown in FIGS. In addition, the predetermined valve opening degree of the conductance variable valves 31a and 31b was 80%.

  FIG. 3 is a graph showing the relationship between the opening and the pressure of the conductance variable valve 31b. Since the valve opening exceeded a predetermined valve opening 80% around 15 minutes, the raw material heating temperature was kept at a constant value (5 ° C. ) Raised. Thereby, since the saturated vapor pressure in the evaporation source gradually increased, the valve opening gradually decreased thereafter (20 to 35 minutes). Then, since the raw material monomer started to change with the heating temperature raised, the valve opening gradually increased from around 35 minutes. In this case, the pressure was constant at 3 Pa.

FIG. 4 shows the measurement result of the film formation rate. The pressure was constant at 3 Pa, the film formation rate was always the same, and the film could be formed at the same film formation rate during the film formation time. I understood. FIG. 5 shows the results of FTIR measurement. The pressure is constant at 3 Pa, and the 2275 cm ⁻¹ peak by FTIR measurement is also constant. It was found that could be formed.
(Comparative example)
Except for using an apparatus that does not include the conventional supply amount control means 30a and 30b, film formation was performed by the same film formation method using the same film formation apparatus as in the examples. The results are shown in FIGS. FIG. 6 shows the measurement results of the film formation rate. As the pressure gradually decreased with time, the film formation rate also decreased, and the film could not be formed at the same film formation rate during the film formation time. I understood. FIG. 7 shows the results of FTIR measurement. As the pressure gradually decreases with time, the 2275 cm ⁻¹ peak by FTIR measurement gradually decreases, and a film having the same composition is formed during the film formation time. I realized that I couldn't.

  According to the film forming apparatus and the film forming method of the present invention, the supply rate of the evaporative gas flowing into the vacuum film forming chamber is controlled to keep the film forming speed constant, and a high quality polymer film can be stably formed. Can be formed. Therefore, it can be used in the semiconductor manufacturing field.

It is a cross-sectional schematic diagram of the film-forming apparatus of this embodiment. It is a flowchart for demonstrating the film-forming method of this embodiment. It is a graph which shows the relationship between the opening degree of a conductance variable valve, and a pressure. It is a graph which shows the change of the pressure and the film-forming speed with respect to the film-forming time in an Example. It is a graph which shows the pressure with respect to the film-forming time in an Example, and the result of FTIR measurement. It is a graph which shows the change of the pressure and the film-forming speed with respect to the film-forming time in a comparative example. It is a graph which shows the pressure with respect to the film-forming time in a comparative example, and the result of FTIR measurement.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Deposition chamber 11 Vacuum exhaust means 12 Mixing chamber 13 Shower plates 20a, 20b Source gas supply means 21a, 21b Evaporation sources 22a, 22b Heating means 23a, 23b Pipes 30a, 30b Supply amount control means 31a, 31b Conductance variable valve 32a, 32b Pressure gauge 33a, 33b Control unit

Claims (5)

A vacuum film formation chamber in which a film formation target is installed; an evaporation source in which a raw material monomer is sealed; and a heating unit provided in the evaporation source, and the raw material monomer is heated and evaporated by the heating unit. A film forming apparatus that introduces the obtained evaporation gas into the vacuum film forming chamber and deposits the evaporated gas on the surface of the film forming target to form a film;
A conductance variable valve and a pressure gauge are provided in a raw material pipe connecting the vacuum film formation chamber and the evaporation source, and a pressure value measured by the pressure gauge is set in the conductance variable valve. A control unit for controlling the opening of the conductance variable valve so as to be equal to the measured pressure value ,
The control unit is also connected to the heating unit. When the opening of the conductance variable valve reaches a predetermined value, the control unit increases the heating temperature of the raw material monomer by the heating unit by a predetermined value. It is comprised so that the film-forming apparatus characterized by the above-mentioned .   The film forming apparatus according to claim 1, wherein the pressure gauge is provided between the conductance variable valve of the raw material pipe and the vacuum film forming chamber.   Two evaporation sources are provided for one vacuum film forming chamber, and the conductance variable valve and the pressure are connected to the material pipe connected to at least one of the two evaporation sources. The film forming apparatus according to claim 1, wherein a total is provided. A film forming method in which an evaporation gas obtained by heating and evaporating a raw material monomer in an evaporation source is introduced into a vacuum film forming chamber and vapor-deposited on the surface of the film forming target to form a film,
A pressure value measured by a pressure gauge provided in a raw material pipe connecting the vacuum film forming chamber and the evaporation source is equal to a pressure value set by a conductance variable valve provided in the raw material pipe. To adjust the opening of the conductance variable valve ,
When the opening of the conductance variable valve reaches a predetermined value, the heating means
A film forming method, wherein the heating temperature of the monomer is increased by a predetermined value . 1,12-Diaminododecane and 1,3-bis (isocyanatomethyl) cyclohexane as the raw material monomers are sealed in different evaporation sources, respectively, and evaporating gas obtained by heating and evaporating each is used. When introducing into a vacuum film formation chamber and vapor-depositing on the surface of the film formation target, and polymerizing at the same time,
At least, according to claim 4, wherein the adjusting the opening of the variable conductance valve provided in the feed pipe to be connected to the 1,3-bis said evaporation source (isocyanatomethyl) cyclohexane is sealed The film forming method.

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