JP2010114188A - Semiconductor manufacturing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that when an apparatus for forming an HfO<SB>2</SB>(hafnium oxide) film by an ALD (Atomic Layer Deposition) method supplies TEMAH and O<SB>3</SB>alternately to a reaction chamber to form the HfO<SB>2</SB>film, the TEMAH receives heat in the reaction chamber to be decomposed and then an Hf film is formed in a TEMAH supply nozzle and peels to become particles. <P>SOLUTION: In the vertical batch type semiconductor manufacturing apparatus which forms the HfO<SB>2</SB>film, piping temperature from a vaporizer to a gas intake of a supply means for TEMAH is controlled to above vaporization temperature of the vaporizer and below thermal decomposition temperature of the TEMAH. Consequently, thermal decomposition of TEMAH is not caused in TEMAH supply piping to suppress formation of the Hf film, thereby reducing particles. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a vertical batch type semiconductor manufacturing apparatus for manufacturing a semiconductor device by forming an HfO ₂ film on the surface of a semiconductor wafer (hereinafter referred to as a wafer).

As a vertical batch type substrate processing apparatus, ALD (Atomic Layer Deposition) using TEMAH (Hf [NCH ₃ C ₂ H ₅ ] ₄ , tetrakismethylethylaminohafnium) as a reaction gas and O ₃ (ozone) as an oxidizing gas. There is an apparatus for forming an HfO ₂ (hafnium oxide) film by a method. In this apparatus, TEMAH avoids the direction of the wafer in the reaction chamber and is supplied by, for example, a TEMAH supply nozzle that is supplied from the upper part of the reaction chamber, and O ₃ is supplied by an O ₃ supply nozzle that supplies gas in the direction of the wafer. Supplied. It is known that an HfO ₂ film with good film thickness uniformity can be formed by alternately supplying TEMAH and O ₃ to the reaction chamber. When the HfO ₂ film is formed by the above-described method, TEMAH receives heat in the reaction chamber and is thermally decomposed before being supplied into the reaction chamber, and an Hf film is formed in the TEMAH supply nozzle. Since the Hf film formed in the TEMAH supply nozzle is peeled off when the cumulative film thickness is about 0.5 μm, replacement of the TEMAH supply nozzle or in situ cleaning using an etching gas is required when the cumulative film thickness is 0.5 μm or less. It becomes. When in situ cleaning was attempted using HF as an etching gas, the HfO ₂ film (composition ratio Hf: O = 1: 2) formed in the reaction chamber or on the wafer could be removed, but HfO formed in the TEMAH nozzle. _{Since the two} films (composition ratio Hf: O = 30: 1) are rich in Hf, they cannot be completely removed by etching. Therefore, in Patent Document 1, in the step of supplying TEMAH into the reaction chamber, O ₃ is also supplied from the TEMAH supply nozzle, and the HfO ₂ film formed in the TEMAH supply nozzle is replaced with the HfO ₂ film formed on the reaction chamber or on the wafer. It has been proposed to perform in situ cleaning by making it the same as (composition ratio Hf: O = 1: 2).
JP 2008-78448 A

However, the method for supplying O ₃ from the TEMAH supply nozzle in the step of supplying TEMAH into the reaction chamber has the following problems. Since the TEMAH supply nozzle extends from the lower part of the reaction chamber to the upper part of the reaction chamber, the amount of heat received by the gas is different between the lower part of the reaction chamber and the outlet near the upper part of the reaction chamber. For this reason, a uniform HfO ₂ film (composition ratio Hf: O = 1: 2) cannot be formed on the entire surface of the TEMAH supply nozzle. Since the heat amount in the lower part of the reaction chamber of the TEMAH supply nozzle is small, O ₃ and Hf do not react sufficiently to form a Hf-rich HfO ₂ film, and the heat amount increases toward the upper part of the reaction chamber and increases in the reaction chamber and on the wafer. It approaches the HfO ₂ film to be formed (composition ratio Hf: O = 1: 2). Further, since the film thickness of the HfO ₂ film formed in the lower part and the upper part in the TEMAH supply nozzle is also different, even if in situ cleaning is performed, the inside of the nozzle cannot be uniformly etched. . The remaining film causes particles due to film peeling, and overetching damages the quartz surface and accelerates the quartz replacement cycle.

The present invention aims to suppress particles due to peeling of the HfO ₂ film formed in the TEMAH supply nozzle, and provides a semiconductor manufacturing apparatus with good film thickness uniformity.

In order to solve the above problems, the semiconductor manufacturing apparatus of the present invention is first provided with a reaction chamber that accommodates a plurality of wafers in a stacked state, and a heating unit that heats the atmosphere in the wafer and the reaction chamber. Yes. Next, a first gas supply means for supplying TEMAH into the reaction chamber, a vaporization means for vaporizing TEMAH, and a second gas supply means for supplying O ₃ are provided. Next, control for controlling the discharge means for discharging the atmosphere in the processing chamber, the heating means, the first gas supply means, the vaporization means, the second gas supply means, and the discharge means. Department. The gas introduction port into the reaction chamber of the first gas supply means opens at a position higher than the stacked wafers, and the gas introduction port into the reaction chamber of the second gas supply means is the reaction chamber. An opening is made in the direction of the wafer stacked in the chamber. Further, in the semiconductor manufacturing apparatus of the present invention, the control unit alternately supplies and exhausts TEMAH and O ₃ to form an HfO ₂ film on the wafer.

  In such a semiconductor manufacturing apparatus, the piping temperature from the vaporization means to the gas inlet of the first gas supply means is controlled to be equal to or higher than the vaporization temperature of the vaporizer and equal to or lower than the thermal decomposition temperature of TEMAH, and TEMAH is placed in the reaction chamber. It is characterized by supplying.

  According to the present invention, by setting the temperature in the TEMAH supply nozzle to be equal to or higher than the vaporization temperature and equal to or lower than the thermal decomposition temperature, it is possible to prevent re-liquefaction of TEMAH supplied in the gas phase and to deposit the Hf film in the TEMAH supply nozzle. Therefore, particles due to peeling off of the Hf film can be suppressed. Furthermore, when performing in-situ cleaning using an etching gas, the temperature in the TEMAH supply nozzle is controlled to be equal to or lower than the etching temperature of quartz according to the present invention, so that the cleaning in the reaction chamber can be performed without etching the TEMAH supply nozzle. Become. Therefore, the replacement frequency of the TEMAH supply nozzle can be reduced.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram of a semiconductor manufacturing apparatus according to the present invention. In FIG. 1, a reaction tube 5 is formed of a heat-resistant and corrosion-resistant metal such as quartz and is supported by a manifold 8. The manifold 8 is open downward and extends the furnace port of the reaction tube 5 downward. An exhaust pipe 14 is connected to the manifold 8, and a pump 10 that evacuates the reaction chamber 1 and a pressure control valve 9 that controls the pressure of the reaction chamber are connected to the exhaust pipe 14. The thermocouple 17 for monitoring the temperature of the reaction chamber with O ₃ supply nozzle 13 of the O ₃ is a reaction gas used for film formation is connected to the Manufacturing hold 8.

  A cylindrical heater 4 is provided in the heater chamber 6 so as to surround the reaction chamber 1, and the required electric power calculated by the controller 22 from the value of the thermocouple 17 is used to set the desired temperature in the reaction chamber 1. 4 is fed back to control the temperature of the reaction chamber 1.

  The boat 2 installed on the seal cap 23 is loaded with wafers 3, and a boat elevator (not shown) for loading the boat 2 into the reaction chamber 1 is connected to the seal cap 23 portion. Then, the boat 2 filled with the wafer 3, the seal cap portion 23, and the boat rotation mechanism 7 are driven up and down to perform loading and unloading into the reaction chamber 1.

The boat 2 is supported by a central portion of a boat support base 24 attached to the tip of a rotating shaft (not shown) that passes through the axial center of the seal cap 23 up and down, and the rotating shaft is a seal cap. It is attached to the lower part of 23. And it connects with the boat rotation mechanism 7 which transmits rotational driving force by making the seal cap 23 into a fixed system. When the boat rotation mechanism 7 is driven, the rotation shaft rotates and the boat 2 rotates via the boat support 24, so that TEMAH and O ₃ supplied to the reaction chamber 1 inside the reaction tube 5 are transferred to each wafer 3. Since the contact is even, an environment with a uniform in-plane film thickness can be obtained.

Next, a TEMAH and O ₃ supply system used for film formation will be described.

  Since TEMAH is a liquefied gas that is liquid at room temperature, TEMAH controlled to a desired flow rate by the TEMAH flow rate control unit 15 is vaporized by the vaporizer 16 and supplied into the reaction chamber 1. A valve 11a is provided upstream of the TEMAH flow control unit 15, and the valve 11a is opened when the TEMAH is used, and closed when the TEMAH is not used. The temperature of the vaporizer 16 is equal to or higher than the vaporization temperature of TEMAH, and the temperature is set to 150 ° C., for example.

  Next, the TEMAH supply pipe 21 will be described with reference to FIGS. 3A and 3B show the states of the cross sections along arrows A and B in FIG. 2, respectively. 3A is a cross-sectional view of the TEMAH supply pipe 21, and FIG. 3B is a perspective view including a cross section of the TEMHA supply pipe 21.

  The TEMAH supply pipe 21 is connected to the vaporizer 16, passes through the heater chamber 6, and is connected to the upper center of the reaction tube 5. As shown in FIG. 3A, the TEMAH supply pipe 21 has a double pipe structure including an inner pipe 28 and an outer pipe 29, and TEMAH flows in the inner pipe 28 (TEMAH flow path 31). A refrigerant for controlling the temperature of the TEMAH supply pipe 21 flows between the inner pipe 28 and the outer pipe 29 (refrigerant flow path 32). Further, between the inner tube 28 and the outer tube 29, as shown in FIGS. 3A and 3B, the volumes of the inner tube 28 and the outer tube 29 are equal to each other perpendicular to the inner tube 28 and the outer tube 29 in the longitudinal direction. A partition plate 30 is provided so as to be divided. One of the spaces between the inner pipe 28 and the outer pipe 29 divided by the partition plate 30 is a refrigerant supply path 25 and the other is a refrigerant discharge path 26. The temperature of the refrigerant is controlled to a desired temperature by the chiller 20, the refrigerant is supplied from the refrigerant supply pipe 18 to the refrigerant supply path 26, and returns from the refrigerant discharge path 27 to the chiller 20 through the refrigerant discharge pipe 19. By repeating the cycle, the temperature of the TEMAH supply pipe 21 can be controlled to a desired temperature.

The optimal temperature of the refrigerant | coolant supplied to the TEMAH supply piping 21 is demonstrated using FIG. FIG. 4 is a drawing showing the degree of thermal decomposition of TEMAH. TEMAH begins to thermally decompose from around 180 ° C. and increases with increasing temperature, but does not thermally decompose at temperatures below 160 ° C. That is, by setting the temperature in the TEMAH supply pipe 21 to 160 ° C. or less, formation of the HfO ₂ film in the pipe can be prevented. However, when the temperature of the refrigerant is set to 150 ° C. or lower of the vaporizer 16 temperature, TEMAH is reliquefied from a gas phase state to a liquid state, causing particles and abnormal film quality. In view of the above, the present invention is characterized in that the temperature of the refrigerant supplied to the TEMAH supply pipe 21 is controlled to be not lower than the temperature of the vaporizer and not higher than the thermal decomposition temperature of TEMAH.

O ₃ is controlled to a desired flow rate by the gas flow rate controller 12 and is supplied into the reaction chamber 1 by the O ₃ supply nozzle. A valve 11b is provided downstream of the gas flow control unit 12, and the valve 11b is opened when O _{3 is} used and closed when not used. The O ₃ supply nozzle 13 extends to the vicinity of the ceiling of the reaction tube 5 along the wafer 3 filled in the boat 2, and the introduction port into the reaction chamber 1 is provided with a plurality of supply holes. Are provided at predetermined intervals in the vertical direction so as to be introduced horizontally.

  The controller 22 that operates as control means is the flow control of the gas flow control unit 12 and the TEMAH flow control unit 15, the opening and closing operation of the valve 12, the pressure adjustment operation of the pressure control valve 9, the temperature adjustment of the heater 4, and the discharge means. The start / stop operation of the vacuum pump 10 and the rotation speed adjustment of the boat rotation mechanism 7 are executed and controlled based on the film forming recipe.

Next, as an example of a film forming process using an ALD (Atomic Layer Deposition) method, a case where an HfO ₂ film is formed using TEMAH and O ₃ , which is one of semiconductor device manufacturing processes, will be described. In the ALD method, under certain film forming conditions (temperature, time, etc.), at least two kinds of reactive gases used as film forming materials are alternately supplied onto the substrate one by one, and the wafer 3 is obtained in units of one atom. In this method, the film is adsorbed on the film formation surface and film formation is performed using a surface reaction. At this time, the film thickness is controlled by the number of cycles for supplying the reactive gas.

<Example 1>
First, as described above, the wafer 3 is filled in the boat 2 and charged into the reaction chamber 1. After carrying the boat 2 into the reaction chamber 1, the following three steps are sequentially executed.

(Step 1)
In step 1, the valve 11 a is opened, and the liquid TEMAH whose flow rate is controlled to 0.01 to 0.2 g / min by the TEMAH flow rate control unit 15 is vaporized by the vaporizer 16. The temperature of the vaporizer is set to be equal to or higher than the vaporization temperature of TEMAH, for example, 150 ° C. At this time, the temperature of the chiller 20 is set so that the temperature of the TEMAH supply pipe 21 is equal to or higher than the temperature of the vaporizer 16, for example, 150 ° C. or higher and equal to or lower than the thermal decomposition temperature of TEMAH, and the refrigerant is supplied into the TEMAH supply pipe 21. . Further, the valve opening degree of the pressure control valve 9 is appropriately adjusted, and the inside of the reaction chamber 1 is maintained at a predetermined pressure. The time for exposing the wafer 30 to the TEMAH gas is 30 to 180 seconds. At this time, the temperature of the heater 4 is set so that the temperature of the wafer 3 is in the range of 180 to 250 ° C., for example, 250 ° C. . When TEMAH is supplied into the reaction chamber 1, it undergoes surface reaction (chemical adsorption) with a surface portion such as a base film on the wafer 3.

(Step 2)
After the supply of TEMAH, the valve 11a is closed, the supply of TEMAH gas is stopped, and the surplus is exhausted (purged). At this time, the pressure control valve 9 is held in an open state, exhausted by the vacuum pump 10, and residual TEMAH gas is removed from the reaction chamber 1. At this time, if an inert gas such as N 2 is supplied into the reaction chamber 1, the exhaust efficiency of the residual TEMAH gas is improved.

(Step 3)
Opening the valve 11b, it is supplied into the reaction chamber 1 a O ₃ controlled to a desired flow rate by the gas flow control unit 12 by the O ₃ supply nozzle 13. At this time, the exhaust of the reaction chamber 1 is continued by the vacuum pump 10 as a discharge means, and the excess is exhausted from the exhaust pipe 14. At this time, the inside of the reaction chamber 1 is maintained at a predetermined pressure by appropriately adjusting the pressure control valve 9. The time for exposing the wafer 3 to O ₃ is 10 to 120 seconds. At this time, the temperature of the wafer 4 is maintained at a predetermined temperature of 180 to 250 ° C. as in the supply of the TEMAH gas in Step 1. The temperature is set. By supplying O _3, the surface reaction between TEMAH and O ₃ chemically adsorbed on the surface of the wafer 3, HfO ₂ film is formed on the wafer 3. After the film formation, the valve 11b is kept closed, and the gas atmosphere in the reaction chamber 1 is evacuated by the vacuum pump 10. By this exhaust, O ₃ remaining in the reaction chamber 1 is excluded. At this time, when an inert gas such as N ₂ is supplied into the reaction chamber 1, the exhaust efficiency of the residual O ₃ gas is increased. Greatly improved. When the above steps 1 to 3 are set as one cycle and this cycle is repeated a plurality of times, an HfO ₂ film having a predetermined thickness is formed on the wafer 3.

According to the above-described embodiment, since the reaction chamber 1 does not have a nozzle for supplying TEMAH into the reaction chamber 1, the heat of the heater 4 is received before TEMAH is supplied into the reaction chamber 1. The thermal decomposition of TEMAH does not occur. However, also in the embodiment of the present invention in which the inlet for supplying the TEMAH to the reaction chamber 1 is connected to the upper portion of the reaction tube 5, the TEMAH supply pipe 21 needs to pass through the heater chamber 6. Receives heat. As a result of measuring the temperature of the heater chamber when the film forming temperature is 250 ° C., the temperature becomes 200 to 205 ° C., so that TEMAH is thermally decomposed in the heater chamber 6. In the present invention, in order to solve the above-described problem, the temperature in the TEMAH supply pipe 21 is set to be equal to or higher than the vaporizer temperature and equal to or lower than the thermal decomposition temperature of TEMAH, thereby suppressing particles due to HfO ₂ film peeling and uniform film thickness. A semiconductor manufacturing apparatus with good performance can be realized.

As described above, the present invention is a vertical batch type semiconductor manufacturing apparatus for forming an HfO ₂ film, which is a semiconductor manufacturing apparatus capable of suppressing particles and having good film thickness uniformity, and improving the quality of the semiconductor device. Can be made.

1 is a configuration diagram of a semiconductor device of the present invention. The block diagram of the supply piping of this invention. Sectional drawing of the supply piping of this invention. The graph which shows the thermal decomposition degree of TEMAH.

Explanation of symbols

1 reaction chamber 2 boat 3 wafer 4 heater 5 reaction tube 6 heater chamber 7 boat rotating mechanism 8 Manufacturing hold 9 pressure control valve 10 vacuum pump 11 valve 12 gas flow controller 13 O ₃ supply nozzle 14 exhaust pipe 15 TEMAH flow control unit 16 Vaporizer 17 Thermocouple 18 Refrigerant supply pipe 19 Refrigerant discharge pipe 20 Chiller 21 TEMAH supply pipe 22 Controller 23 Seal cap 24 Boat support base 25 TEMAH flow path 26 Refrigerant supply flow path 27 Refrigerant discharge flow path 28 Inner pipe 29 Outer pipe 30 Partition plate 31 TEMAH flow path 32 Refrigerant flow path

Claims (1)

A reaction chamber for storing a plurality of wafers in a stacked state, a heating means for heating the atmosphere in the wafer and the reaction chamber, a first gas supply means for supplying TEMAH into the reaction chamber, and for vaporizing TEMAH A vaporization means; a second gas supply means for supplying O ₃ ; a discharge means for discharging the atmosphere in the processing chamber; the heating means; the first gas supply means; the vaporization means; 2 gas supply means, and a control unit for controlling the discharge means,
The gas introduction port into the reaction chamber of the first gas supply unit opens at a position higher than the stacked wafers, and the gas introduction port into the reaction chamber of the second gas supply unit enters into the reaction chamber. In the vertical batch type semiconductor manufacturing apparatus in which the direction toward the laminated wafer is opened and the control unit alternately supplies and exhausts TEMAH and O ₃ to form an HfO ₂ film on the wafer.
A pipe temperature from the vaporization means to the gas inlet of the first gas supply means is controlled to be not less than the vaporization temperature of the vaporizer and not more than the thermal decomposition temperature of TEMAH, and TEMAH is supplied into the reaction chamber Manufacturing equipment.

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