JP4463583B2 - Film forming method and film forming apparatus - Google Patents

Description

  The present invention relates to a film formation technique, and more particularly to a technique for forming a ferroelectric or high dielectric metal oxide film by MOCVD.

In the semiconductor manufacturing process, thin films made of various substances are formed on a substrate (wafer) that is an object to be processed. In response to the diversification of physical properties required for this thin film, it is used for thin film formation. Diversified and complicated materials and combinations are progressing. For example, in recent years, the use of a PZT film has attracted attention as a memory capacitor material for a planar stack type FeRAM, and development of a technique for generating a high-quality PZT film with high reproducibility is underway. The PZT film, which is a multi-component metal oxide thin film, is a crystal film having a perovskite structure of Pb (Zr _1-x Ti _x ) O ₃ and has ferroelectricity.

When a multi-component metal oxide thin film such as PZT is formed by chemical vapor deposition (MOCVD) using an organometallic compound as a raw material, the substrate placed in the reaction vessel is heated, and a raw material gas and an oxidizing gas are supplied thereto. (For example, Patent Document 1). The film formation temperature of PZT is usually 500 to 650 ° C., and O ₂ is used as the oxidizing gas. However, depending on the device structure, the allowable film formation temperature may be 500 ° C. or less, and such a low temperature. When film formation is performed in a region, NO ₂ (nitrogen dioxide) having excellent oxidizing power is used as the oxidizing gas (for example, Patent Document 2). As the source gas, for example, Pb (dpm) ₂ , Zr (Oi-C ₃ H ₇ ) ₂ (dpm) ₂ , or Zr (in addition to the organometallic raw materials described in Patent Document 1 and Patent Document 2) Use an organometallic raw material or the like composed of a combination of Oi-C ₃ H ₇ ) (dpm) ₃ or Zr (dpm) ₄ and Ti (Oi-C ₃ H ₇ ) ₂ (dpm) _2. Can do.

In this case, it is desirable to use a postmix-type shower head in order to form a high-quality thin film on the substrate. That is, a source gas and an oxidizing gas supply channel and discharge holes are independently formed in the shower head, and the film forming reaction is performed by mixing the source gas and the oxidizing gas in the space immediately above the substrate in the reaction vessel. Like that. By doing so, the reaction between the source gas and the oxidizing gas mainly takes place in the vicinity of the wafer surface, so that an improvement in film quality (for example, crystallinity) can be expected, and the gas phase inside the shower head can be expected. Since the reaction is suppressed, the generation of particles can be expected to be suppressed.

  Since the raw material gas is constantly in contact with the surface of the shower head, the shower head is heated by a heater so that the raw material does not condense on the surface. By discharging and supplying the source gas and the oxidizing gas from the shower head for film formation, a film is slightly formed on the surface of the shower head (including the vicinity of the source gas discharging hole and the oxidizing gas discharging hole) as well as the wafer. accumulate. This film is considered to be an oxide, a raw material decomposition product, or the like generated and deposited by the reaction between the raw material gas and the oxidizing gas on the surface of the heated shower head. In a general CVD apparatus, it is possible to always maintain a clean shower head surface by periodically performing dry cleaning for removing such a surface deposited film, but in the PZT film forming process, It is very difficult to perform effective dry cleaning, and it is difficult to completely remove the deposited film. Therefore, as the PZT film forming process is carried out for a long period of time, a film of the raw material reactant is gradually deposited on the showerhead surface. If this deposited film is in close contact with the surface of the shower head and does not peel off permanently, there will be no problem, but in practice the shower head and the deposited film will thermally expand or contract due to temperature fluctuations of the shower head. When this occurs, stress is applied to the interface between the showerhead member and the deposited film due to the difference in thermal expansion coefficient between the showerhead member (for example, aluminum) and the deposited film, and the deposited film is peeled off or collapsed. If the deposited film is peeled off or collapsed as particles and falls onto the wafer, there arises a problem that the product yield of the semiconductor device formed on the wafer deteriorates.

  In the PZT film formation by the CVD method, as described above, it is difficult to remove the deposit by dry cleaning, so that the deposited film is peeled off or collapsed or the discharge hole of the oxidizing gas is clogged. The generated shower head must be replaced and cleaned each time, and there is a problem that the operating rate of the apparatus is lowered and the maintenance cost is increased.

  In order to avoid such a problem, in order to reliably control the temperature of the shower head, a flow path through which the heat medium flows is provided inside the shower head, and the heat medium is circulated therein, so that The method of giving and receiving heat is mentioned.

However, the postmix type shower head is provided with the supply path and discharge holes for the source gas and the oxidizing gas independently, and the pitch of the discharge holes is narrowed in order to improve the uniformity of gas ejection, Forming the cooling medium flow path while avoiding such complicated and narrow supply paths and discharge holes is accompanied with great difficulty in processing. Further, even if it can be formed, the cooling medium flow path becomes narrower and the flow rate of the circulating cooling medium is limited to a small value. There is also a problem that failure due to blockage of the medium flow path is likely to occur.
JP 2000-260766 A JP 2000-58526 A

The present invention has been made in view of such circumstances, and an object thereof is to provide a film forming method and a film forming apparatus capable of effectively preventing clogging of a shower head.
Another object of the present invention is to provide a film forming method and a film forming apparatus capable of improving the uniformity and reproducibility of film formation.
Furthermore, an object of the present invention is to provide a film forming method and a film forming apparatus capable of realizing improvement in the operation rate of the apparatus and reduction in maintenance cost.
Still another object of the present invention is to provide a film forming method and a film forming apparatus that can prevent the generation of particles from the surface of the shower head.

In order to solve the above problems, according to a first aspect of the present invention, a shower head having a plurality of gas discharge holes for independently discharging an organic metal raw material and an oxidizing gas into a processing chamber for accommodating a substrate to be processed. And forming the metal oxide on the substrate to be processed by mixing the organometallic raw material and the oxidizing gas in the processing chamber, and facing the substrate to be processed of the shower head The temperature of the shower head is detected by a temperature sensor disposed in the vicinity of the processed surface, the temperature of the shower head gas deposition holes and the reaction product deposition on the surface facing the substrate to be processed, and the organometallic The shower head is heated or cooled by a heating means and / or a cooling means so as to suppress the condensation of the raw material, so that the temperature of the shower head is increased. To provide a film forming method characterized by controlling the.

In a second aspect of the present invention, an organometallic raw material and an oxidizing gas are supplied into a processing chamber that accommodates a substrate to be processed through a shower head having a plurality of gas discharge holes that discharge these separately and independently. A film forming method for forming a metal oxide on the substrate to be processed by mixing an organic metal raw material and an oxidizing gas in the processing chamber, wherein the shower is performed according to supply conditions of the organic metal raw material and the oxidizing gas. Knowing the temperature of the shower head capable of suppressing the deposition of reaction products and the condensation of the organometallic raw material on the gas discharge hole of the head and the surface facing the substrate to be processed, wherein the temperature sensor disposed in proximity to opposing surfaces by detecting the temperature of the shower head, the temperature of deposition and of the organic metal source of the reaction product So that the contraction in the suppressible temperature, by heating or cooling the shower head by the heating means and / or cooling means to provide a film forming method characterized by controlling the temperature of the shower head.

According to a third aspect of the present invention, there is provided a processing chamber that accommodates a substrate to be processed, and a shower head that is provided in the processing chamber and has a plurality of gas discharge holes that separately discharge an organic metal raw material and an oxidizing gas. A film forming apparatus for forming a metal oxide on the substrate to be processed by mixing the organometallic raw material and the oxidizing gas in the processing chamber, and heating means and / or cooling the shower head. A cooling unit, a temperature detecting unit for detecting the temperature of the shower head, and a reaction product in which the temperature of the shower head detected by the temperature detecting unit faces the gas discharge hole of the shower head and the substrate to be processed. so that the deposition and condensation of the organometallic material to suppress the temperature, a temperature control mechanism for controlling the heating means and / or cooling means, Further comprising the cooling means of the shower head is a heat pipe, formed, characterized in that at least the heat absorption end of the heat pipe is arranged close to the surface facing the substrate to be processed of said showerhead A membrane device is provided.

According to a fourth aspect of the present invention, there is provided a processing chamber that accommodates a substrate to be processed, and a shower head that is provided in the processing chamber and has a plurality of gas discharge holes for separately discharging an organic metal source and an oxidizing gas. A film forming apparatus for forming a metal oxide on the substrate to be processed by mixing the organometallic raw material and the oxidizing gas in the processing chamber, and heating means and / or cooling the shower head. A cooling means, a temperature detecting means for detecting the temperature of the shower head, and reaction generation on the surface of the shower head facing the gas discharge hole and the substrate to be processed according to the supply conditions of the organometallic raw material and the oxidizing gas Storage means for storing information on the temperature of the shower head capable of suppressing accumulation of substances and condensation of the organometallic raw material, and information stored in the storage means The temperature of the shower head detected by the temperature detection means suppresses the deposition of reaction products and the condensation of the organometallic raw material on the gas discharge holes of the shower head and the surface facing the substrate to be processed. A temperature control mechanism for controlling the heating means and / or the cooling means so as to reach a temperature , wherein the cooling means of the shower head is a heat pipe, and at least the endothermic end of the heat pipe is the heat absorption end. Provided is a film forming apparatus characterized in that it is disposed close to a surface of a shower head facing a substrate to be processed .

  In the present invention, a heat pipe disposed in the shower head can be adopted as the heating means and / or cooling means of the shower head. In the case where a heat pipe is used as the cooling means for the shower head, at least the endothermic end of the heat pipe can be disposed close to the surface of the shower head facing the substrate to be processed. In addition, a temperature sensor that detects the temperature of the surface of the shower head that faces the substrate to be processed can be used as a temperature detection unit that detects the temperature of the shower head, and the temperature sensor is the substrate to be processed of the shower head. It is preferable that it is arranged in the vicinity of the surface facing the.

In addition, as the organometallic raw material used in the present invention, metal β-dikenate or metal alkoxide can be used. Moreover, Pb (dpm) ₂ , Zr (dpm) ₄ , Zr (Oi-C ₃ H ₇ ) (dpm) ₃ , Zr (OiC ₃ H ₇ ) ₂ (dpm) ₂ , Ti (Oi-C ₃ H ₇ ) ₂ (dpm) ₂ , Ba (dpm) ₂ , Sr (dpm) ₂ can be used, and in this case, oxidation The gas is preferably selected from the group consisting of N ₂ O, NO ₂ , and O ₂ .

As an organic metal raw material used in the present invention, HTB (hafnium tetratertiary terboxide) or ZTB (zirconium tetratertiary terboxide) can also be used. In this case, the oxidizing gas is NO ₂ or O _3. It is preferable that

As a specific example, the organometallic raw material includes Pb (dpm) ₂ as a Pb-containing raw material, Zr (dpm) ₄ or Zr (OiC ₃ H ₇ ) ₂ (dpm) ₂ as a Zr-containing raw material, or It includes _{Zr (O-i-C 3} H 7) (dpm) 3, Ti as Ti-containing raw material _{(O-i-C 3 H} 7) 2 (dpm) 2, the oxidizing _gas, N 2 _O, NO ₂ , selected from the group consisting of O ₂ and the formation of a PZT film is exemplified by these.

  According to the present invention, the shower head temperature is controlled so as to suppress the deposition of reaction products and the condensation of the organometallic raw material on the gas discharge holes of the shower head and the surface facing the substrate to be processed. A plurality of independent gas supply paths provided in the head can be prevented from becoming clogged by being narrowed or clogged with deposits, etc., and film formation uniformity and reproducibility can be maintained high. In addition, the maintenance frequency of the shower head is reduced, and the operating rate of the film forming apparatus can be improved and the maintenance cost can be reduced. Further, depending on the supply conditions of the organometallic raw material and the oxidizing gas, the shower is controlled so as to suppress deposition of reaction products and condensation of the organometallic raw material on the gas discharge holes of the shower head and the surface facing the substrate to be processed. The above effect can be further enhanced by controlling the temperature of the head.

  Further, according to the present invention, if necessary, a heat pipe is provided in the shower head, so that the shower head can be soaked without forming a complicated heat medium passage having a high processing cost in the shower head. And temperature control by efficient cooling becomes possible, and temperature control of the shower head can be effectively performed at low cost and with high reliability.

Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view of an example of the configuration of a film forming apparatus that performs a film forming method according to an embodiment of the present invention. FIG. 2 is a flowchart showing an example of the operation thereof, and FIG. FIG. 4 is a conceptual diagram illustrating an example of the determination table.

  As shown in FIG. 1, this film forming apparatus has a casing 1 having a substantially rectangular cross section made of, for example, aluminum, and is formed in a bottomed cylindrical shape inside the casing 1. The treated container 2 is provided. An opening 2a is provided at the bottom of the processing container 2. From the outside of the opening 2a, the transmission window 2d made of transparent quartz can be kept airtight by the sealing member 2c made of an O-ring. is set up. A lamp unit (not shown) is connected to the lower part of the transmission window 2d. A lid 3 that supports a shower head 40 described later is provided on the upper portion of the processing container 2 so as to be openable and closable.

  On the upper surface of the shower head 40, a temperature control mechanism 90 including a plurality of annular heaters 91 and a water cooling flow path 92 through which a heat medium such as cooling water flows is disposed. The temperature of the shower head 40 is set to a predetermined value by heating or cooling the shower head 40 by feedback control by a process controller 80 described later using a measurement result of the temperature of the shower head 40 measured by the thermocouple 10 described later. It is possible to control to the value of.

  A cylindrical shield base 8 is erected from the bottom of the processing container 2 inside the processing container 2. An annular base ring 7 is disposed in the opening above the shield base 8, and an annular attachment 6 is supported on the inner peripheral side of the base ring 7, and is supported by a step portion on the inner peripheral side of the attachment 6. A mounting table 5 on which the wafer W is mounted is provided. A baffle plate 9 described later is provided outside the shield base 8.

  A plurality of exhaust ports 9 a are formed in the baffle plate 9. A bottom exhaust passage 71 is provided at a position surrounding the shield base 8 at the inner peripheral bottom of the processing container 2, and the inside of the processing container 2 is located at the bottom exhaust passage 71 through the exhaust port 9 a of the baffle plate 9. In this way, the processing container 2 is exhausted uniformly.

  A wafer entrance / exit 15 communicating with the processing space S is provided on the side surface of the housing 1, and the wafer entrance / exit 15 is connected to a load lock chamber (not shown) via a gate valve 16.

  The above-described lid 3 is provided in an opening portion at the top of the processing container 2, and a shower head 40 described later is provided at a position facing the wafer W placed on the mounting table 5 of the lid 3.

  A cylindrical reflector 4 is erected from the bottom of the processing vessel 2 in a space surrounded by the mounting table 5, the attachment 6, the base ring 7, and the shield base 8, and this reflector 4 is a lamp unit (not shown). The heat rays radiated from the laser beam are reflected and guided to the lower surface of the mounting table 5 so that the mounting table 5 is heated efficiently. Further, the heating source is not limited to the above-described lamp, and a resistance heating body may be embedded in the mounting table 5 to heat the mounting table 5.

The reflector 4 is provided with slit portions at, for example, three locations, and arms 14 that support lift pins 12 for lifting the wafer W from the mounting table 5 are disposed at positions corresponding to the slit portions so as to be movable up and down. The lift pin 12 is supported by an annular holding member 13 provided outside the reflector 4 via the arm 14, and moves up and down by moving the holding member 13 up and down by an actuator (not shown). The lift pins 12 are made of a material that transmits heat rays irradiated from the lamp unit, for example, quartz or ceramic (Al ₂ O ₃ , AlN, SiC).

  The lift pins 12 are raised until the lift pins 12 protrude from the mounting table 5 by a predetermined length when the wafer W is delivered, and when the wafer W supported on the lift pins 12 is mounted on the mounting table 5, The lift pins 12 are drawn into the mounting table 5.

  A reflector 4 is provided at the bottom of the processing vessel 2 directly below the mounting table 5 so as to surround the opening 2a. A gas shield 17 made of a heat ray transmitting material such as quartz is provided on the inner periphery of the reflector 4. It is attached by being supported all around. The gas shield 17 has a plurality of holes 17a.

In addition, purge gas (for example, inert gas such as N ₂ or Ar gas) from the purge gas supply mechanism is formed in the space between the lower transmission window 2d supported by the inner periphery of the reflector 4 and the lower transmission window 2d. The gas is supplied through a purge gas channel 19 formed at the bottom of the processing vessel 2 and gas ejection ports 18 that are in communication with the purge gas channel 19 and are equally distributed at eight locations on the inner lower side of the reflector 4.

  The purge gas supplied in this way flows into the back side of the mounting table 5 through the plurality of holes 17 a of the gas shield 17, so that the processing gas from the shower head 40 to be described later is a space on the back side of the mounting table 5. To prevent the penetration window 2d from being damaged such as the deposition of a thin film.

  The shower head 40 made of aluminum or the like has a cylindrical shower base 41 formed so that its outer edge is fitted to the upper portion of the lid 3, and a disk-shaped gas diffusion plate 42 that is in close contact with the lower surface of the shower base 41. And a shower plate 43 attached to the lower surface of the gas diffusion plate 42.

  The shower base 41 is fixed to the lid 3 with screws. The joint between the shower base 41 and the lid 3 is hermetically sealed by an O-ring. The shower base 41 and the gas diffusion plate 42 are hermetically sealed by an O-ring, and the shower base 41, the gas diffusion plate 42, and the shower plate 43 are screwed.

  The shower base 41 is provided in the center of the shower base 41, and is disposed at a symmetrical position with a raw material gas introduction path 41a to which the raw material gas pipe 51 is connected, and the raw material gas introduction path 41a interposed therebetween, and an oxidizing gas pipe 52. The oxidizing gas branch pipes 52a and the oxidizing gas branch pipes 52b are connected to each other.

The source gas pipe 51 and the oxidizing gas pipe 52 are connected to the gas supply mechanism 60. The gas supply mechanism 60 has a raw material tank and a vaporizer for each raw material. The liquid raw material supplied from each raw material tank, for example, Pb (dmp) dissolved in a solvent such as butyl acetate, octane, or THF (tetrahydrofuran). ) ₂ , Zr (Oi-C ₃ H ₇ ) (dmp) ₃ , Ti (Oi-C ₃ H ₇ ) ₂ (dmp) ₂ are vaporized by a vaporizer to become a raw material gas, It is mixed at a predetermined ratio (for example, a ratio such that elements such as Pb, Zr, Ti, O constituting PZT have a predetermined stoichiometric ratio) and supplied to the source gas pipe 51. The gas supply mechanism 60 has an oxidizing gas source, and NO ₂ or the like is supplied from the oxidizing gas source to the oxidizing gas pipe 52.

On the upper surface side of the gas diffusion plate 42, a source gas diffusion space 42a communicating with a source gas introduction path 41a to which the source gas pipe 51 is connected is provided. The source gas diffusion space 42a includes the gas diffusion plate 42 and the shower plate. 43 is formed so as to penetrate through 43 and communicate with a source gas passage 42 d opened on the lower surface of the shower plate 43.
An oxidizing gas diffusion space 42 b is provided on the lower surface side of the gas diffusion plate 42, and this oxidizing gas diffusion space 42 b is connected to the shower base 41 via an oxidizing gas passage 42 e formed through the gas diffusion plate 42. It communicates with the oxidizing gas introduction path 41b. The lower oxidant gas diffusion space 42b is provided with a plurality of cylindrical protrusions 42j, part of which is a gas passage column 42f formed with a source gas passage 42d penetrating through the center. . The height of the gas passage column 42f (and the other cylindrical projection 42j) is substantially equal to the depth of the oxidizing gas diffusion space 42b, and is formed on the upper surface of the shower plate 43 that is in close contact with the lower side of the gas diffusion plate 42. It is in close contact. The position of the gas passage column 42f is arranged at the position of a later-described source gas discharge hole 43a of the shower plate 43 that is in close contact with the lower side so as to coincide with the source gas passage 42d. Further, all the cylindrical protrusions 42j may be gas passage columns 42f.

  In the shower plate 43, a plurality of source gas discharge holes 43a and a plurality of oxidizing gas discharge holes 43b are alternately arranged and formed. That is, each of the plurality of source gas discharge holes 43a is arranged at a position overlapping the source gas passage 42d so as to communicate with the plurality of source gas paths 42d of the upper gas diffusion plate 42, and the plurality of oxidizing gas discharge holes 43b. Are arranged so as to open in the gaps between the plurality of gas passage columns 42 f in the oxidizing gas diffusion space 42 b of the upper gas diffusion plate 42.

  In the shower plate 43, a plurality of source gas discharge holes 43 a connected to the source gas pipe 51 are arranged on the outermost periphery, and the oxidizing gas discharge holes 43 b and the source gas discharge holes 43 a are alternately and evenly arranged inside thereof. The

  That is, the shower head 40 of the present embodiment has a plurality of source gas discharge holes 43 a connected to the source gas pipe 51 and an oxidizing gas discharge hole 43 b connected to the oxidizing gas branch pipe 52 a on the lower surface of the shower plate 43. This is a so-called postmix type in which the gas is opened independently and the source gas and the oxidizing gas are mixed in the space immediately above the wafer W in the processing chamber 2. Here, the description is based on the example in which the source gas is introduced into the upper source gas diffusion space 42a and the oxidizing gas is introduced into the lower oxidizing gas diffusion space 42b. The oxidizing gas may be introduced into the space 42a, and the source gas may be introduced into the lower oxidizing gas diffusion space 42b.

  The laminated shower base 41, gas diffusion plate 42, and shower plate 43 have a thermocouple insertion hole 41i, a thermocouple insertion hole 42g, and a thermocouple insertion hole 43c for mounting the thermocouple 10 in the thickness direction. It is provided at the overlapping position, and the temperature inside the lower surface of the shower plate 43 and the shower head 40 can be measured and input to the process controller 80.

  In the present embodiment, the temperature control mechanism 90 is connected to the process controller 80 via the temperature control unit 93 and the external output interface 83. The thermocouple 10 that measures the temperature of the lower surface of the shower plate 43 and / or the interior of the shower head 40 is connected to the process controller 80 via the external input interface 82, and the lower surface of the shower plate 43 and / or the shower head 40. Is input to the process controller 80. The process controller 80 outputs control signals such as the heater power supply amount, the cooling water flow rate and the temperature to the temperature control mechanism 90 via the external output interface 83 and the temperature control unit 93 based on the input temperature information and the like. The temperature of the lower surface of the shower head 40 and the shower plate 43 is controlled.

  The process controller 80 controls the entire apparatus including the temperature control of the shower head 40 based on a processing recipe (not shown) stored in the process database 84. The process controller 80 is connected to a user interface 81 (not shown) such as a display and a keyboard. The process controller 80 can be used to specify a processing recipe by inputting a command or the like from the outside, or to display the operation status on the display for monitoring. Operation is possible. The process controller 80 may be operated by incorporating control software.

By the way, when the shower head is a post-mix type like the shower head 40 and the oxidizing gas to be used is a strong oxidizing agent such as NO ₂ , the oxidizing gas which is the supply path of the oxidizing gas that opens to the shower plate 43 is used. When the lower surface temperature of the shower plate 43 is high or when the flow rate of the oxidizing gas is large, white or brown deposits grow around the oxidizing gas discharge hole 43b and the hole 43b tends to be clogged. This contributes to a decrease in film formation uniformity and reproducibility.

FIGS. 9A and 9B are cross-sectional views showing a state before the oxidizing gas discharge hole 43b is clogged and a state after the clogging. When the diameter d0 of the oxidizing gas discharge hole 43b is, for example, 0.7 mm, the deposit gradually grows as shown in FIG. 9A from the state of FIG. At the same time as the shape protruding from the surface of the shower plate 43 like a pot, the clogging causes the substantial diameter d to be reduced to 0.1 mm, thereby deteriorating film formation uniformity and reproducibility. When this white or brown deposit was analyzed by EDX, it was inferred that the constituents were oxides of Pb, Zr, and Ti, and the main component was probably an incomplete oxide of Pb. Since such deposits are not seen around the raw material discharge holes, in the temperature zone around the shower head surface temperature (approximately 150 to 250 ° C.), a region where the partial pressure of NO ₂ is extremely high (that is, shower) This phenomenon is considered to occur only in the vicinity of the oxidizing gas discharge hole of the head. This phenomenon, while clogging how holes becomes faster conspicuous as the flow rate of NO ₂ gas is large as described above, NO ₂ partial pressure in the oxidizing gas discharge holes near as the flow rate of NO ₂ gas is large showerhead It can be explained from the fact that the price increases.

  Therefore, in the present embodiment, in order to determine whether or not clogging of the oxidizing gas discharge hole 43b is likely to occur in the process database 84, a determination table 85 as illustrated in FIG. Thus, the clogging of the oxidizing gas discharge hole 43b is prevented.

  That is, this determination table 85 includes an oxidation described later for each combination of various oxidizing gas supply conditions Y (for example, the flow rate of oxidizing gas) and the lower surface temperature t of the shower plate 43 detected by the thermocouple 10 at that time. A gas clogging degree value D of the gas discharge hole is stored.

For example, as shown in FIG. 9 (a), the hole clogging degree value D includes a standard supply amount of oxidizing gas (NO ₂ is 200 mL / min) that is unlikely to block the oxidizing gas discharge hole 43b, and a shower at that time. The degree of clogging under other conditions when the temperature of the lower surface of the plate 43 (170 ° C.) is 1, for example, the period of use of the apparatus or the number of deposited films until the substantial diameter d is reduced to 0.1 mm, or Compare the processing gas supply amount, etc., or how long the equipment is used, the number of depositions, or the processing gas supply amount until the film formation uniformity and reproducibility deteriorate due to clogging of the generated holes. Quantified and stored in a simple way.

  In the table of FIG. 4, when the hole clogging degree value D is 1 or less, the clogging or narrowing of the oxidizing gas discharge hole 43b is unlikely to occur and can be used without any problem. The clogging degree value D is 2 or more. However, this is a range in which the oxidizing gas discharge hole 43b is blocked and narrowed and cannot be used. Therefore, in the present embodiment, the process controller 80 determines that the hole is in a range that can be used if the hole clogging degree value D is 1.5 or less between 1 and 2.

FIG. 3 is a diagram in which the distribution of the hole clogging degree value D in FIG. 4 is plotted, with the hole clogging degree value D of 1 being “◯”, 2 being “□”, and an intermediate 1.5 Is indicated by “Δ”. In the present embodiment, the range of the curve A or less obtained by connecting the data with the hole clogging degree value D of 1.5 is determined as the range in which the oxidizing gas discharge hole 43b can be continuously processed without being blocked. The process is controlled as described below. This determination may be made by directly referring to the determination table 85 and reading out the lower surface temperature t of the shower plate 43 such that the hole clogging degree value D becomes 1.5, for example, or the supply conditions of the oxidizing gas The determination may be made using determination logic 86 based on the following equation (1) that gives the lower surface temperature t of the shower plate 43 when the hole clogging degree value D becomes 1.5, for example. In the formula (1), D is a clogging degree value, A is a constant, and is 3.743 × 10 ⁻⁵ .

  That is, in the equation (1), a shower plate that can be continuously processed without blocking the oxidizing gas discharge hole 43b by using 1.5 as the hole clogging degree value D and giving the oxidizing gas supply condition Y. 43 usable lower limit temperature t 'is obtained.

Then, when the supply condition Y such as the flow rate of the oxidizing gas specified by the processing recipe specified via the user interface 81 is given, the process controller 80 searches the process database 84 using this supply condition Y and oxidizes. The operation of determining and outputting the lower surface temperature t of the shower plate 43 in a range where the gas discharge holes 43b are not clogged is performed. Alternatively, based on the supplied supply condition Y, the determination logic 86 calculates the expression (1) and outputs the corresponding lower surface temperature t of the shower plate 43. That is, the range of the lower surface temperature t of the shower plate 43 commanded by the process controller 80 is that the raw material liquefaction temperature ≦ t ≦ t ′.
The supply condition Y may be not only the flow rate of the oxidizing gas but also the partial pressure of the oxidizing gas or the ratio of the partial pressure of the source gas and the partial pressure of the oxidizing gas.

  The detailed description of the method for deriving the equation (1) and the method for calculating the coefficient of the equation (1) is omitted here, but basically, the Arrhenius equation representing the reaction rate constant, Further, it can be obtained by modifying two equations of the reaction rate constant, the gas concentration, and the deposition rate, and inputting the deposition rate data with respect to the temperature. In addition, the constant A and the value 6862.6 in the formula (1) mentioned here can be used by appropriately changing depending on the type of raw material and oxidizing gas to be used, as well as components other than PZT. Needless to say, it can also be applied to membrane processes. In the present embodiment, the distance from the lower surface of the shower plate 43 to the mounting table 5 is 25 mm, the diameters of the source gas discharge holes 43a and the oxidizing gas discharge holes 43b are 0.7 mm, and the hole pitch is 12 mm ( 1) Although the constants of the equation have been determined, it is desirable to appropriately change each constant according to the situation of the apparatus to be used.

Next, an example of a film forming method using the film forming apparatus of this embodiment will be described with reference to FIGS.
First, when an operator selects, for example, a recipe for PZT film formation from the outside on the user interface 81 (step 201), the process controller 80 selects the pressure in the processing space S corresponding to the recipe specified from the process database 84. Then, various film formation condition data such as the supply flow rate of the source gas, the supply flow rate of the oxidizing gas, and the heating temperature of the wafer W on the mounting table 5 are read (step 202).

  Then, the process controller 80 searches the determination table 85 based on the supply condition Y such as the supply flow rate of the oxidizing gas and sets the lower surface temperature of the shower head 40 (shower plate 43) (step 203).

For example, when the flow rate of the oxidizing gas (for example, NO ₂ ) specified in the recipe is 200 mL / min as the supply condition Y, the determination table 85 illustrated in FIG. 4 shows that the lower surface temperature t of the shower plate 43 is 190 ° C. or higher. Since the clogging degree value D exceeds 1.5 (1.95 to 6.35), it is not preferable. At 180 ° C., the clogging degree value D is 1.41, and clogging of the oxidizing gas discharge hole 43b hardly occurs. . Therefore, in this case, the usable lower limit temperature t ′ of the shower plate 43 is determined to be 190 ° C. Here, if the set temperature of the shower head 40 and the shower plate 43 immediately before that is lower than 190 ° C., the temperature control of the shower head 40 and the shower plate 43 is continued without changing the set temperature. Conversely, when the set temperatures of the shower head 40 and the shower plate 43 immediately before that are 190 ° C. or higher, the process controller 80 sets a lower surface temperature t of the shower plate 43 to a value lower than 190 ° C., for example, 180 ° C. .

  When both the supply flow rate of the oxidizing gas (supply condition Y) and the lower surface temperature t of the shower plate 43 are specified in the specified recipe (step 204), the process controller 80 sets the supply condition Y and With reference to the determination table 85 based on the two pieces of information of the lower surface temperature t, it is determined whether or not the hole clogging degree value D is 1.5 or less (step 205). The following film forming process is started (step 211), and if it exceeds 1.5, the operator is warned that the condition is that the oxidizing gas discharge hole 43b for blowing the oxidizing gas in the shower plate 43 is blocked (step). 206). Here, the operator (1) continues the process while being aware of the risk of the blockage (step 211), and (2) continues the process after changing the value of the lower surface temperature t of the shower plate 43. (Step 209, Step 210), (3) It is possible to select one of the options consisting of canceling the processing (Step 207).

  In addition, although it is about the case where it is determined that the usable lower limit temperature t ′ of the shower plate 43 is 220 ° C. or higher, as described above, when the shower head surface temperature exceeds approximately 220 ° C., Another problem that the deposited film peels and collapses to become particles occurs, so that the lower surface temperature t of the shower plate 43 is set in a range not exceeding 220 ° C. As one specific example, when it is determined that the usable lower limit temperature t ′ of the shower plate 43 is 240 ° C., the lower temperature t of the shower plate 43 is set to 220 ° C. (step 208).

  The film forming process in step 211 described above is performed as follows as an example. First, the inside of the processing container 2 is exhausted to a vacuum degree of 1 to 4 Torr, for example, by being exhausted by a vacuum pump (not shown) via an exhaust path such as the bottom exhaust passage 71.

  At this time, a purge gas such as Ar is supplied from the carrier / purge gas supply source (not shown) to the back surface (lower surface) side of the gas shield 17 from the plurality of gas ejection ports 18 via the purge gas flow path 19. It passes through the hole 17 a of the shield 17 and flows into the back side of the mounting table 5, flows into the bottom exhaust passage 71 through the gap of the shield base 8, and enters the transmission window 2 d located below the gas shield 17. A steady purge gas flow is formed to prevent damage such as deposition of the thin film.

  In the processing container 2 in this state, the wafer W is loaded via the gate valve 16 and the wafer entrance / exit 15 by a robot hand mechanism (not shown), and lift pins 12 supported by the holding member 13 and the arm 14 by an actuator (not shown). Is raised so as to protrude onto the mounting table 5, and the wafer W is placed on the lift pins 12. Then, a robot hand mechanism (not shown) is retracted from the processing container 2 and the gate valve 16 is closed.

  Next, the lift pins 12 are lowered to place the wafer W on the mounting table 5, and the lamp of a lamp unit (not shown) below is turned on so that the heat rays pass through the transmission window 2 d and the lower surface (rear surface) of the mounting table 5. The wafer W irradiated to the side and mounted on the mounting table 5 is heated to a temperature of, for example, 500 ° C., for example, between 450 ° C. and 700 ° C. Note that the lamp of the lamp unit described above may be lit at all times for the purpose of shortening the temperature stabilization time, extending the lamp life, or the like.

  At this time, since the lower surface of the shower plate 43 is heated by the radiant heat from the mounting table 5 and the wafer W, the process controller 80 detects the lower surface temperature t of the shower plate 43 by the thermocouple 10, and this temperature is the above-described step. The temperature control mechanism 90 is controlled so as to maintain the value set in 203, and temperature control such as heating and cooling of the shower head 40 is performed.

Then, the thus heated the wafer W, from a plurality of raw material gas discharge holes 43a of the lower surface of the shower plate 43 of the shower head 40, for _{example, Pb (dmp) 2, Zr} (O-i-C 3 H ₇ ) (dmp) ₃ , Ti (Oi-C ₃ H ₇ ) ₂ (dmp) ₂ is a predetermined ratio (for example, elements such as Pb, Zr, Ti, etc. constituting PZT have a predetermined stoichiometric ratio) The raw material gas mixed at such a ratio is discharged and supplied, and NO _{2 and the} like are discharged and supplied from the oxidizing gas discharge holes 43b, respectively. Through the chemical reaction, a thin film made of PZT is formed on the surface of the wafer W.

  That is, the vaporized source gas coming from the gas supply source passes through the source gas pipe 51 and the source gas diffusion space 42a of the gas diffusion plate 42, the source gas passage 42d, and the source gas discharge hole 43a of the shower plate 43 together with the carrier gas. Then, it is discharged and supplied to the upper space of the wafer W.

  Similarly, the oxidizing gas supplied from the oxidizing gas source passes through the oxidizing gas pipe 52, the oxidizing gas branch pipes 52a and 52b, the oxidizing gas introduction path 41b of the shower base 41, and the oxidizing gas path 42e of the gas diffusion plate 42. It reaches the oxidizing gas diffusion space 42 b and is discharged and supplied to the upper space of the wafer W via the oxidizing gas discharge hole 43 b of the shower plate 43. In this way, the raw material gas and the oxidizing gas are separately supplied into the processing container 2 so as not to be mixed in the shower head 40. The film thickness, composition, and crystallinity of the thin film formed on the wafer W are controlled by controlling the supply time and flow rate of the source gas and the oxidizing gas, the pressure in the processing space S, the temperature of the mounting table 5, and the like. .

In the case of the present embodiment, the lower surface temperature t is set in accordance with the supply condition Y such as the flow rate of the oxidizing gas so that the hole clogging degree value D is 1.5 or less. 9B, the oxidizing gas discharge hole 43b of the shower plate 43 through which the oxidizing gas such as NO ₂ blows out is not blocked or narrowed by deposits as shown in FIG. 9B. Since the preferable opening state of (a) is maintained, it is possible to prevent the film formation uniformity and reproducibility of the PZT film formed on the wafer W from being deteriorated, and when processing a plurality of wafers W continuously. Therefore, it is possible to achieve good film formation uniformity and reproducibility. Furthermore, since the maintenance frequency of the shower plate can be reduced, the maintenance cost can be reduced and the apparatus operating rate can be improved.

Next, as a second embodiment of the present invention, the process controller 80 and the temperature control mechanism 90 form a film using the shower head 40 at a temperature of 220 ° C. or lower and a strong oxidizing agent such as NO ₂ as the oxidizing gas. In the case of performing the above, the case where the temperature of the shower head 40 is controlled to 175 ° C. or lower will be described.

  As described above, a film is slightly deposited on the surface of the shower head by discharging and supplying the source gas and the oxidizing gas from the shower head for film formation. In the PZT film forming process, it is difficult to perform dry cleaning and the deposited film cannot be completely removed. Therefore, as the film is continuously formed, a film of a raw material reactant is gradually deposited on the surface of the shower head. If the deposited film is peeled off or collapsed and falls onto the wafer as particles, there arises a problem that the product yield of the semiconductor device formed on the wafer deteriorates. Here, since the relationship between the shower head surface temperature and the number of particles on the wafer can be expressed as shown in FIG. 10, if the shower head surface temperature is about 220 ° C. or less, the deposited film on the shower head surface It can be prevented from peeling and collapsing into particles. That is, from the viewpoint of preventing particle generation, the temperature of the shower head 40 needs to be controlled to 220 ° C. or less.

Further, the above-mentioned organometallic raw materials (for example, Pb (dmp) ₂ , Zr (Oi-C) other than the organometallic raw materials described in Patent Document 1 and Patent Document 2, which are generally used in the PZT film forming process, are used. _{3 H 7) 2 (dmp)} 2 or _{Zr, (O-i-C} 3 H 7) (dmp) 3, or Zr _{(dmp) 4,} and _{Ti (O-i-C 3} H 7) 2 (dmp) Most of the organic metal raw materials composed of the combination of the _two are not clearly pyrolyzed, and the decomposition starts from about 100 to 200 ° C., decomposes rapidly from 200 to 300 ° C., and completely around 300 to 400 ° C. It has the property of decomposing. When the temperature inside the shower head 40 is high, non-uniform thermal decomposition of the raw material gas (film forming raw material) occurs at a high temperature portion of the raw material gas flow path inside the shower head 40, and a thin film formed on the wafer W There is concern that the controllability and uniformity of the composition will be adversely affected. Further, the solid matter (decomposition reaction product) generated by thermal decomposition of the source gas in the shower head 40 becomes a foreign matter (particle) and adheres to the wafer W, which is a cause of deterioration of the product yield of the semiconductor device. It becomes. For this reason as well, it is important that the temperature of the shower head 40 is not set higher than necessary.

  On the other hand, the temperature at which the aforementioned organometallic raw material begins to condense is approximately 100 to 150 ° C., so the temperature of the shower head 40 needs to be controlled to 150 ° C. or higher. Accordingly, the temperature of the shower head 40 is controlled in the range of at least 150 to 220 ° C., preferably 160 to 180 ° C., for example, 170 ° C.

  In the case of the present embodiment, by setting the temperature of the shower head 40 in the range of 150 to 220 ° C. as described above, the deposited film on the surface of the shower plate 43 is prevented from peeling and collapsing into particles. In addition, it is possible to reliably avoid undesirable thermal decomposition in the flow path of the source gas inside the shower head 40, and the reaction product may adhere to the wafer W as foreign matter (particles). It is reliably prevented and the quality and yield of the PZT film formed on the wafer W can be improved.

Further, in the case of forming a film using a strong oxidant such as NO ₂ as the oxidizing gas, the oxidizing gas formed on the shower plate 43 is set by setting the lower surface temperature t of the shower plate 43 to 175 ° C. or lower. Occlusion and narrowing due to deposits adhering to the discharge holes 43b are prevented, and the film formation uniformity and reproducibility of the PZT film on the wafer W can be improved. Furthermore, since the maintenance frequency of the shower plate can be reduced, the maintenance cost can be reduced and the apparatus operating rate can be improved.

The third embodiment of the present invention will be described with reference to FIG. In FIG. 5, the same elements as those in the apparatus configuration example illustrated in FIG.
In the above-described embodiment, the installation place of the heater 91 and the water cooling channel 92 is the upper part of the shower base 41, that is, the atmosphere side, and the temperature control of this part is relatively easy. However, in many MOCVD (metal organic chemical vapor deposition) processes such as PZT film formation, the heating temperature of the wafer W reaches 400 to 650 ° C. Therefore, the heat radiation from the mounting table 5 and the wafer W causes the shower plate 43 to be heated. Excessive heat input is generated on the bottom surface.

  As a result, the temperature of the lower surface of the shower plate 43 is likely to rise, so that a temperature difference is likely to occur between the upper portion of the shower base 41 (atmosphere side) and the lower surface of the shower plate 43 (vacuum side facing the wafer). May affect the temperature control. Such a temperature difference is caused when the thickness of the shower head 40 is large (for example, 50 mm or more), or when the number of plates constituting the shower head 40 is large (for example, in this embodiment, the shower base 41, gas diffusion). Plate 42 and shower plate 43 in total) and the gas diffusion space of gas diffusion plate 42 is large, and heat transfer from shower plate 43 to shower base 41 does not go smoothly, or shower head 40 is made of stainless steel. This may be noticeable when the material is made of a material such as steel, which has a relatively poor thermal conductivity.

  Aluminum is exposed on the lower surface of the shower plate before film formation, and the heat absorption rate is relatively low. However, as described above, deposited films such as oxides and raw material decomposition products adhere to the lower surface of the shower plate as described above. To do. Since the surface of this deposited film is dark and has a relatively high heat absorption rate, it has the property of absorbing more heat than the lower surface of the shower plate before film formation. In addition, as the temperature on the lower surface of the shower plate increases, the tendency of decomposition and adhesion of the raw material accelerates, so deposition film deposition ⇒ Increase in heat absorption rate on the lower surface of the shower plate ⇒ Increase in shower plate temperature ⇒ Further deposition film deposition Undesirable circulation can also occur. If such a phenomenon occurs, there is a possibility that the temperature difference between the upper portion of the shower head and the lower surface of the shower plate will gradually increase as the film formation is repeated.

  If the temperature difference between the upper portion of the shower head and the lower surface of the shower plate is 25 ° C., the temperature at the upper portion of the shower head 40 must be lowered to 145 ° C. in order to keep the lower surface of the shower plate 43 at 170 ° C. Don't be. However, as described above, the temperature at which the organometallic raw material begins to condense is approximately 100 to 150 ° C., so it is not preferable to create a portion having a temperature of 150 ° C. or less in the shower head 40.

  As a technique for solving the above problems, a refrigerant flow path is installed in the shower head (or the shower head member itself), the refrigerant is circulated therein, and the radiant heat received from the mounting table is removed. Is mentioned. Ideally, the coolant flow path inside the shower head should be installed inside the shower plate that receives radiant heat from the mounting table or the like, but the interval between the discharge holes of the processing gas (raw material gas and oxidizing gas) of the shower plate ( The hole pitch) is very narrow (in this embodiment, 7 mm) in order to improve the ejection uniformity of the processing gas, and it is very difficult to dig a refrigerant channel between them, and even if it is dug well, the refrigerant flow Since the path is narrow, the flow rate of the coolant that can flow there becomes a small value, and there remains a problem that a sufficient cooling effect cannot be obtained and a problem that the coolant flow path is easily clogged.

  In the third embodiment, a heat pipe 101 is used as a part of a temperature control mechanism 90 that controls the temperature of the shower head 40. That is, the plurality of heat pipes 101 are arranged so as to penetrate the shower base 41 and the gas diffusion plate 42 constituting the shower head 40, and the lower end (endothermic end) portion is located near the lower surface of the shower plate 43. .

  A heat pipe is a container in which a small amount of liquid (working fluid) is vacuum-sealed in a metal sealed container (pipe) excellent in thermal conductivity, and a capillary structure (wick) is provided on the inner wall. Many heat pipes use deionized water as the working fluid and copper as the pipe. Since the amount of hydraulic fluid enclosed in the heat pipe is very small (for example, 1 cc or less), there is almost no risk of liquid leakage. Here, the operation principle of the heat pipe will be described below. When a part of the heat pipe is heated, the hydraulic fluid evaporates in the heating part (absorption of latent heat of vaporization), then the steam moves to the low temperature part, and the vapor condenses (releases latent heat of vaporization) in the low temperature part. Heat is transferred by a series of phase changes in which the condensed liquid circulates to the heating part by capillary action. Since the steam flow inside the heat pipe moves at a speed close to the speed of sound, the heat transfer speed is extremely fast, and as a result, the heat response is extremely fast. The heat pipe is characterized by being capable of transporting a large amount of heat with a very low temperature gradient and having an excellent thermal conductivity of about 80 times that of a copper rod. The heat pipe also has a feature that it can be processed into various shapes such as bending while maintaining its heat transport capability.

  As described above, since the heat pipe 101 is formed of a copper cylinder, care must be taken in the method of incorporating it into the shower head. In the semiconductor manufacturing process, if contamination of the wafer by copper (Cu metal contamination) occurs in the semiconductor manufacturing process, it seriously affects the characteristics of the semiconductor product on the wafer. This is because it is necessary to pay attention so as not to be exposed.

  As an example of heat pipe incorporation, for example, the whole (or part) of the heat pipe 101 is inserted into an aluminum member (not shown) in which a hole enough to hold the heat pipe is drilled in advance, and brazing or electron beam Embedded and sealed by welding. By using an O-ring for separating the atmosphere side and the vacuum side, the exposed portion of the heat pipe 101 is limited to the atmosphere side, and copper is not exposed to the vacuum side. By doing in this way, it is possible to prevent contamination of the shower head 40, the processing container 2, etc. with copper. The same applies to other heat pipe examples described later.

  The individual heat pipes 101 are arranged between the source gas discharge holes 43a and the oxidizing gas discharge holes 43b in the gas diffusion plate 42 and the shower plate 43 so as not to interfere with both. The number and arrangement interval of the heat pipes 101 may be appropriately determined depending on the amount of heat to be removed. In recent years, thin heat pipes having a diameter of 1 to 3 mm, called micro heat pipes, are commercially available and are available from manufacturers such as Fujikura Co., Ltd. and Furukawa Electric Co., Ltd. If this micro heat pipe is used for the heat pipe 101, it can be sufficiently installed even when the arrangement interval and arrangement pitch of the source gas discharge holes 43a and the oxidizing gas discharge holes 43b are narrow (for example, 7 mm or less). If only the heat pipe 101 disposed between the source gas discharge hole 43a and the oxidizing gas discharge hole 43b is insufficient in heat transport amount, a thick heat pipe having a large heat transport amount is appropriately added to the side wall portion of the shower head 40. You may arrange.

  In order to hold the shower head 40 at 170 to 200 ° C. in a state of receiving radiant heat from a mounting table or the like, an ability to remove heat of about 2 kW is required. If one having an appropriate performance is selected, one heat pipe has a heat transport amount of about 500 W. Therefore, if the required number (for example, four or more) of heat pipes is used in the vertical direction, the shower head 40 It is easy to move 2 kW of heat from the lower part to the upper part of the shower head 40.

  Further, in order to install the heat pipe 101, a hole that penetrates the shower base 41 and the gas diffusion plate 42 of the shower head 40 in the thickness direction is simply formed, and an O-ring is appropriately disposed. A complicated and expensive process such as forming a fine refrigerant flow path in the shower plate 43 by sewing the gap between the gas discharge hole 43a and the oxidizing gas discharge hole 43b is completely unnecessary. Therefore, the heat pipe 101 can be installed in the shower head 40 at an extremely low cost. Moreover, since the heat pipe 101 has an average life of 100,000 hours or more, the reliability is extremely high and maintenance is not required.

  At the upper end (heat radiating end) portion of the heat pipe 101 protruding from the shower base 41, for example, a temperature control mechanism 106 including a heater, a heat radiating fin, an electric fan, a refrigerant flow path, a Peltier element, and the like is provided. The process controller 80 controls the amount of heating and heat dissipation in the temperature control mechanism 106 via the external output interface 83 and the temperature controller 93, whereby the entire shower head 40, the oxidizing gas discharge hole 43b, and the like are formed. The temperature of the shower plate 43 is controlled. The temperature control mechanism 90 may be appropriately used with the heater 91 and the water cooling channel 92 described in the first embodiment. Furthermore, temperature detection means such as a thermocouple 10 may be installed in the shower head 40, temperature detection means such as a thermocouple may be installed in the temperature control mechanism 106, or both may be used in combination. . The same applies to other heat pipe examples described later.

  Depending on the film forming process and the showerhead structure, a vertical effect heat pipe 101 can be installed without protruding above the shower base 41, and a sufficient effect can be expected simply by improving the thermal uniformity of the entire showerhead. In such a case, instead of the temperature control mechanism 106 for the heat pipe, only the temperature control mechanism 90 directly above the shower base 41 described in the first embodiment may be provided. . The same applies to other heat pipe examples described later.

  The lower surface of the shower head 40, that is, the lower end surface of the shower plate 43, is likely to rise in temperature due to radiant heat generated by heating the wafer W on the opposite mounting table 5, and temperature control is relatively difficult. By disposing the heat pipe 101 and dissipating the heat of the lower end surface of the shower plate 43 to the upper part of the shower head 40, the lower surface temperature t of the shower plate 43 in which the source gas discharge holes 43a and the oxidizing gas discharge holes 43b are formed. Can be reliably controlled to 220 ° C. or lower, and further to 175 ° C. or lower as described above, without being affected by radiant heat from the mounting table 5 and the wafer W.

  In addition, since the temperature gradient inside the shower head 40 can be extremely reduced by the heat pipe 101 and the thermal uniformity of the entire shower head 40 is improved, precise temperature control of the shower head 40 can be easily performed. It becomes possible.

  As a result, by setting the lower surface temperature t of the shower plate 43 to 220 ° C. or less, it is possible to improve the film quality and yield of PZT and the like by reducing the adhesion of foreign matter (particles) to the wafer W, and depending on the type of oxidizing agent used Since the lower surface temperature t of the shower plate 43 is 175 ° C. or less, the oxidation gas discharge holes 43b can be prevented from being blocked or narrowed by deposits, and film formation uniformity and reproducibility can be improved.

In addition, since the lower surface temperature t of the shower plate 43 can be kept below a certain value, the amount of deposited film adhering to the lower surface of the shower plate 43 can be reduced, so that the deposited film adheres to the lower surface of the shower plate. There is no unfavorable circulation such as an increase in heat absorption rate of ⇒ an increase in shower plate temperature ⇒ further adhesion of the deposited film. That is, since the temperature t on the lower surface of the shower plate 43 can be kept constant even when the number of film formations is increased, film formation with high reproducibility can be performed.
Compared to the method of installing a refrigerant flow path inside the shower head, circulating the refrigerant in it, and removing the radiant heat received from the mounting table, etc., it does not require a high temperature chiller, so the device is made compact It is possible to reduce the maintenance frequency and improve the operation rate of the apparatus, and it is possible to keep the cost low. Moreover, the danger of flowing a high temperature refrigerant | coolant and the danger at the time of the refrigerant | coolant leak inside a shower head can be avoided. Specifically, since the heat pipe has a negative pressure and the liquid contained in the inside is a very small amount of water, there is little danger even if the air tightness of the heat pipe is broken. Compared with, safety can be improved. The refrigerant flow path requires an inlet and an outlet, and there is often a temperature difference between the inlet and the outlet. However, since heat is transported by a single tube in a heat pipe, the installation location and the installation method are different. The degree of freedom is large, and there is no temperature difference due to the installation channel.

  Since the heat-resistant temperature of the heat pipe is about 300 ° C., it is possible to cope with a wider range of process temperatures (for example, the wafer W is 800 ° C.) than a method in which a coolant is flown inside the shower head. The heat pipe is relatively inexpensive, has a stable quality, and has high reliability, so that the maintenance cost of members such as the shower head 40 can be reduced.

  In the present embodiment, the distance between the lower surface of the shower plate 43 and the wafer W is set to 25 mm. Depending on the film forming process conditions, this distance may be short, for example, 15 mm. However, the shorter the distance, the more easily affected by the heat radiation from the mounting table 5 and the wafer W. Although the problem that the temperature easily rises occurs, such a problem can be avoided by using the shower head of the present embodiment using a heat pipe.

  A modification of the heat pipe arrangement method is illustrated in FIG. FIG. 6 shows an example in which the heat pipe 102 is bent and arranged inside the shower head 40. As described above, since the heat pipe 102 is made of a material having good thermal conductivity such as copper, the workability is good and the bending process is easy.

  In the example of FIG. 6, the heat pipe 102 is formed in an L shape, and the lower end (endothermic end) side is radial or latticed in the shower plate 43 so as not to interfere with the source gas discharge holes 43a and the oxidizing gas discharge holes 43b. The upper end (heat radiating end) side penetrates the side wall of the shower head 40 and protrudes above the shower head 40. A temperature control mechanism 106 is attached to the upper end portion protruding on the shower head 40 to constitute a temperature control mechanism 90. In the case of FIG. 6 as well, the same effect as in the case of FIG. 5 described above can be obtained. In some cases, the lower end (endothermic end) of the L-shaped heat pipe 102 is radially or latticed in the gas diffusion plate 42 so as not to interfere with the source gas diffusion space 42a and the oxidizing gas diffusion space 42b. You may make it embed in.

  7 and 8 show still another example of the shower head 40 using a heat pipe. FIG. 8 is a horizontal sectional view of the shower plate 43 of FIG. 7 as viewed from below. In the example of FIG. 7, a plurality of heat pipes 103 and heat pipes 104 are placed in a horizontal posture in the shower plate 43 at the lower end of the shower head 40 so as not to interfere with the source gas discharge holes 43a and the oxidizing gas discharge holes 43b. They are arranged in a grid. As the heat pipe 103 and the heat pipe 104, it is desirable to use the aforementioned micro heat pipe.

  Further, a heat pipe 105 independent of the heat pipe 103 and the heat pipe 104 is vertically arranged at a position penetrating the side wall portion of the shower head 40 in the thickness direction, and a lower end of the vertical heat pipe 105 is horizontally The heat pipe 103 and the heat pipe 104 are close to both ends, and heat is transferred between them.

  The upper end portion of the vertical heat pipe 105 protrudes from the upper portion of the shower head 40, and a temperature control mechanism 106 is attached.

  That is, in the example of FIG. 7, the temperature distribution in the surface of the shower plate 43 is made uniform by the heat pipe 103 and the heat pipe 104 installed horizontally in the surface of the shower plate 43, and the surplus heat is vertical. It is dissipated to the upper part of the shower head 40 via the heat pipe 105.

Accordingly, the same effects as those of FIGS. 5 and 6 described above can be obtained, and further, the in-plane distribution of the film quality such as PZT on the wafer W can be realized by equalizing the in-plane temperature of the shower plate 43.
Accordingly, the same effects as those of FIGS. 5 and 6 described above can be obtained, and further, the in-plane distribution of the film quality such as PZT on the wafer W can be realized by equalizing the in-plane temperature of the shower plate 43.

  In addition, when the heat conductivity between the heat pipe 103 and / or the heat pipe 104 and the heat pipe 105 is more important, the heat pipe 103 and / or the heat pipe 104 and the heat pipe are obtained by welding or bending. You may comprise so that it may connect with 105 directly.

  In some cases, the heat pipe 103 and / or the heat pipe 104 may be embedded in the gas diffusion plate 42 so as not to interfere with the source gas diffusion space 42a and the oxidizing gas diffusion space 42b. Alternatively, the heat pipe 104 may be embedded in both the gas diffusion plate 42 and the shower plate 43.

Moreover, the shower head structure using the heat pipe shown in the above-described FIGS. 5 to 7 may be used alone or in combination.
In the third embodiment described above, the structure of the shower head has been described as a postmix type, but it is needless to say that the present invention can also be applied to a premix type showerhead.

  In the present invention using a heat pipe, when the thickness of the shower head is large, the number of plates constituting the shower head is large, the gas diffusion space inside the shower head is large, or the shower head is made of stainless steel or the like. The effect is particularly significant in an example in which the temperature difference between the upper part and the lower part of the shower head tends to be noticeable, such as when the material is not relatively good in thermal conductivity.

  In the present embodiment, an example of using a heat pipe for the purpose of effectively dissipating radiant heat received from the mounting table or the like received by the shower plate 43 has been described. Can effectively use heat pipes even in the warming direction. For example, when the temperature of the entire shower head 40 is to be quickly raised from room temperature to the operating temperature at the time of starting up the apparatus and the like, if the heater of the temperature control mechanism 106 is turned on and heated, the heat is supplied to the heat pipe. The temperature of the entire shower head 40 can be increased in a short time.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the idea of the present invention. For example, in the above-described embodiment, the PZT thin film forming process is described as an example using the organic metal compound raw material classified as the metal β-dikenate. However, the present invention is not limited to this, and the film forming using the organic metal raw material is performed. If so, it can be applied. For example, as in the case of the PZT film, an organometallic compound classified as a metal β-dikenate can be used as a raw material to form a BST film. This BST film is a crystalline film having a perovskite structure of Ba (Sr _1-x Ti _x ) O ₃ like the PZT thin film, and has ferroelectricity. This film uses Ba (dpm) ₂ as a Ba-containing raw material, Sr (dpm) ₂ as a Sr-containing raw material, and Ti (Oi-C ₃ H ₇ ) ₂ (dpm) ₂ as a Ti-containing raw material. A film can be formed. Further, in the above embodiment, NO ₂ is used as the oxidizing gas. However, when a ferroelectric film such as a PZT thin film is formed using such an organometallic compound material classified as a metal β-dikenate, In addition, N ₂ O and O ₂ can also be used as the oxidizing gas.

The present invention also provides other high / ferroelectric films such as SBT films (oxides containing Sr, Bi and Ta), BLT films (oxides containing Bi, La and Ti), RE -Ba-Cu-O system (RE is a rare earth element), Bi-Sr-Ca- Cu-O system, and high-temperature superconductor film, such as Tl-Ba-Ca-Cu- O _system, Al ₂ O _3, HfO ₂ It is also effective for forming a gate insulating film such as ZrO ₂ or an oxide electrode film such as RuO ₂ , IrO ₂ , or SrRuO. In particular, HfO ₂ and ZrO ₂ are attracting attention among gate insulating film materials, and HTB (hafnium tetratertiary oxide) and ZTB (zirconium tetratertiary oxide), which are organometallic compounds classified as metal alkoxides as raw materials, respectively. Side) can be used for film formation. In this case, NO ₂ or O ₃ is suitable as the oxidizing gas.

  According to the present invention, it becomes possible to prevent clogging of the shower head, thereby improving the uniformity and reproducibility of film formation, improving the operating rate of the apparatus, and reducing the maintenance cost. Since the reduction can be realized, the present invention provides a desired processing by supplying a processing gas from a shower head provided facing a heated substrate mounted on a mounting table in a processing container. It can apply widely to the gas processing apparatus which performs.

1 is a cross-sectional view illustrating an example of a configuration of a film forming apparatus that performs a film forming method according to an embodiment of the present invention. The flowchart which shows an example of an effect | action of the film-forming apparatus which enforces the film-forming method which is one embodiment of this invention. FIG. 5 is a diagram illustrating an example of the operation of a film forming apparatus that performs a film forming method according to an embodiment of the present invention. The conceptual diagram which shows an example of the determination table used with the film-forming apparatus which enforces the film-forming method which is one embodiment of this invention. Sectional drawing which shows the modification of the shower head of the film-forming apparatus which enforces the film-forming method which is one embodiment of this invention. Sectional drawing which shows the modification of the shower head of the film-forming apparatus which enforces the film-forming method which is one embodiment of this invention. Sectional drawing which shows the modification of the shower head of the film-forming apparatus which enforces the film-forming method which is one embodiment of this invention. Sectional drawing which shows the modification of the shower head of the film-forming apparatus which enforces the film-forming method which is one embodiment of this invention. Sectional drawing which shows an example before the oxidizing gas discharge hole in a shower head clogs, and after clogging. The diagram which shows the relationship between shower head surface center temperature and the number of shower head origin particle | grains.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Housing 2 ... Processing container 5 ... Mounting stand 10 ... Thermocouple (temperature detection mechanism)
40 ... Shower head 41 ... Shower base 41a ... Source gas introduction passage 41b ... Oxidation gas introduction passage 42 ... Gas diffusion plate 42a ... Source gas diffusion space 42b ... Oxidation gas diffusion space 42d ... Source gas passage 42e ... Oxidation gas passage 43 ... Shower Plate 43a ... Source gas discharge hole 43b ... Oxidation gas discharge hole 51 ... Source gas pipe 52 ... Oxidation gas pipe 52a ... Oxidation gas branch pipe 52b ... Oxidation gas branch pipe 60 ... Gas supply mechanism 80 ... Process controller 81 ... User interface 82 ... External input interface 83 ... External output interface 84 ... Process database 85 ... Determination table 86 ... Determination logic 90 ... Temperature control mechanism 91 ... Heater 92 ... Water cooling channel 93 ... Temperature control unit 101 ... Heat pipe 102 ... Heat pipe 103 ... Heat Pipe 104 ... Heat pipe 1 5 ... the heat pipe 106 ... temperature control mechanism W ... wafer

Claims (19)

An organometallic raw material and an oxidizing gas are supplied into a processing chamber containing a substrate to be processed through a shower head having a plurality of gas ejection holes for independently ejecting the organometallic raw material and the oxidizing gas, and the organometallic raw material and the oxidizing gas are supplied to the processing chamber. A film forming method for forming a metal oxide on the substrate to be processed by mixing in a room,
The temperature of the shower head is detected by a temperature sensor disposed close to the surface of the shower head facing the substrate to be processed, and the temperature is detected on the surface of the shower head facing the gas discharge hole and the substrate to be processed. The temperature of the shower head is controlled by heating or cooling the shower head by a heating means and / or a cooling means so as to suppress the deposition of reaction products and condensation of the organometallic raw material. A film forming method. An organometallic raw material and an oxidizing gas are supplied into a processing chamber containing a substrate to be processed through a shower head having a plurality of gas ejection holes for independently ejecting the organometallic raw material and the oxidizing gas, and the organometallic raw material and the oxidizing gas are supplied to the processing chamber. A film forming method for forming a metal oxide on the substrate to be processed by mixing in a room,
The shower head capable of suppressing the deposition of reaction products and the condensation of the organometallic raw material on the surface of the shower head facing the gas discharge hole and the substrate to be processed according to the supply conditions of the organic metallic raw material and the oxidizing gas The temperature of the shower head is detected by a temperature sensor disposed in the vicinity of the surface of the shower head facing the substrate to be processed , and the temperature is determined by the deposition of the reaction product and the temperature. A film forming method characterized in that the temperature of the shower head is controlled by heating or cooling the shower head by a heating means and / or a cooling means so that the condensation of the organometallic raw material can be suppressed. The film forming method according to claim 1 or 2 , wherein the heating means and / or cooling means of the shower head is a heat pipe disposed in the shower head. 4. The film forming method according to claim 1, wherein the organometallic raw material is a metal β-dikenate or a metal alkoxide. 5. The organometallic raw materials are Pb (dpm) ₂ , Zr (dpm) ₄ , Zr (Oi-C ₃ H ₇ ) (dpm) ₃ , Zr (Oi-C ₃ H ₇ ) ₂ (dpm) _{2 , Ti (O-i-C} 3 H 7) 2 (dpm) 2, Ba (dpm) 2, Sr (dpm) according claim 1, characterized in that a plurality of species selected from the group consisting of ₂ Item 5. The film forming method according to any one of Items4. The film forming method according to claim 5 , wherein the oxidizing gas is selected from the group consisting of N ₂ O, NO ₂ , and O ₂ . 5. The film forming method according to claim 1 , wherein the organometallic raw material is HTB (hafnium tetratertiary toboxide) or ZTB (zirconium tetratertiary toboxide). . The film forming method according to claim 7 , wherein the oxidizing gas is NO ₂ or O ₃ . The organometallic raw material is Pb (dpm) ₂ as a Pb-containing raw material, Zr (dpm) ₄ or Zr (Oi-C ₃ H ₇ ) ₂ (dpm) ₂ or Zr (O-i as a Zr-containing raw material. include _{-C 3 H 7) (dpm)} 3, Ti as Ti-containing raw material _{(O-i-C 3 H} 7) 2 (dpm) 2, the oxidizing _gas, N 2 _O, from NO 2, _{O 2} The film forming method according to any one of claims 1 to 4 , wherein the PZT film is formed by using a material selected from the group consisting of: A processing chamber for storing a substrate to be processed;
A shower head provided in the processing chamber and having a plurality of gas discharge holes for independently discharging the organic metal raw material and the oxidizing gas, and mixing the organic metal raw material and the oxidizing gas in the processing chamber; A film forming apparatus for forming a metal oxide on the substrate to be processed,
Heating means for heating the shower head and / or cooling means for cooling;
Temperature detecting means for detecting the temperature of the shower head;
The temperature of the shower head detected by the temperature detection means is set to a temperature that suppresses deposition of reaction products and condensation of the organometallic raw material on the gas discharge holes of the shower head and the surface facing the substrate to be processed. A temperature control mechanism for controlling the heating means and / or the cooling means ,
The showerhead cooling means is a heat pipe, and at least the endothermic end of the heat pipe is disposed close to the surface of the showerhead facing the substrate to be processed . A processing chamber for storing a substrate to be processed;
A shower head provided in the processing chamber and having a plurality of gas discharge holes for independently discharging the organic metal raw material and the oxidizing gas, and mixing the organic metal raw material and the oxidizing gas in the processing chamber; A film forming apparatus for forming a metal oxide on the substrate to be processed,
Heating means for heating the shower head and / or cooling means for cooling;
Temperature detecting means for detecting the temperature of the shower head;
The shower head capable of suppressing the deposition of reaction products and the condensation of the organometallic raw material on the gas discharge hole of the shower head and the surface facing the substrate to be processed according to the supply conditions of the organometallic raw material and the oxidizing gas Storage means for storing the temperature information of
Based on the information stored in the storage means, the temperature of the shower head detected by the temperature detection means is such that the deposition of reaction products on the gas discharge holes of the shower head and the surface facing the substrate to be processed and the A temperature control mechanism for controlling the heating means and / or the cooling means so as to suppress the condensation of the organometallic raw material ,
The showerhead cooling means is a heat pipe, and at least the endothermic end of the heat pipe is disposed close to the surface of the showerhead facing the substrate to be processed . 12. The film forming apparatus according to claim 10 , wherein the temperature detecting means is a temperature sensor that detects a temperature of a surface of the shower head that faces the substrate to be processed. The film forming apparatus according to claim 12 , wherein the sensor is disposed in proximity to a surface of the shower head that faces the substrate to be processed. The film forming apparatus according to claim 10 , wherein the organometallic raw material is a metal β-dikenate or a metal alkoxide. The organometallic raw materials are Pb (dpm) ₂ , Zr (dpm) ₄ , Zr (Oi-C ₃ H ₇ ) (dpm) ₃ , Zr (Oi-C ₃ H ₇ ) ₂ (dpm) _{2 , Ti (O-i-C} 3 H 7) 2 (dpm) 2, Ba (dpm) 2, Sr (dpm) according claim 10, characterized in that a plurality of species selected from the group consisting of ₂ 14. The film forming apparatus according to any one of items 13 . The film forming apparatus according to claim 15 , wherein the oxidizing gas is selected from the group consisting of N ₂ O, NO ₂ , and O ₂ . The film-forming apparatus according to any one of claims 10 to 13 , wherein the organometallic raw material is HTB (hafnium tetratertiary toboxide) or ZTB (zirconium tetratertiary toboxide). . The film forming apparatus according to claim 17 , wherein the oxidizing gas is NO ₂ or O ₃ . The organometallic raw material is Pb (dpm) ₂ as a Pb-containing raw material, Zr (dpm) ₄ or Zr (Oi-C ₃ H ₇ ) ₂ (dpm) ₂ or Zr (O-i as a Zr-containing raw material. include _{-C 3 H 7) (dpm)} 3, Ti as Ti-containing raw material _{(O-i-C 3 H} 7) 2 (dpm) 2, the oxidizing _gas, N 2 _O, from NO 2, _{O 2} The film forming apparatus according to claim 10 , wherein the PZT film is selected from the group consisting of:

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