JP2006216597A - Substrate processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure the uniformity of substrate processing by effectively controlling pressure distribution on a substrate at the time of substrate processing in a substrate processing apparatus of type of discharging gases from the side opposite to a gas supplying side with the substrate sandwiched while supplying a gas from the side of the substrate. <P>SOLUTION: The substrate 8 is supported by a susceptor (holder) 3 in a processing chamber 1. Gas supplying ports 19, 20 are configured so as to be provided on the side part of the substrate 8 and the upper part of the substrate 8, and supply the gas to the substrate 8 from the upper part of the substrate 8. A discharging port 16 for discharging the gas inside the processing chamber 1 is provided on the part opposite to the gas supply ports 19, 20 with the substrate 8 sandwiched and lower than the substrate 8. An upper inner wall surface 26a of an upper container 26 of the processing chamber 1 opposing the substrate 8 is configured so as to incline to the substrate 8. The inclination of the wall surface 26a is set so that an opposing distance with the wall surface 26a opposing the substrate 8 may be high from the upstream side of gas flow toward the downstream side thereof. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a substrate processing apparatus for supplying gas from the side of a substrate.

  In recent years, with the miniaturization of semiconductors, the demand for high-quality semiconductor films is increasing, and a film forming method for forming a deposited film at an atomic layer level by supplying two types of reactive gases alternately has attracted attention. . As a material for the reaction gas, a metal-containing raw material and a gas containing oxygen or nitrogen are used. There are two types of film formation methods in view of the reaction form. One is ALD (Atomic Layer Deposition), and the other is MOCVD (Metal Organic Chemical Vapor Deposition) using a cycle method. Since these methods share the same basic gas supply method, they will be described using FIG. 6 in common. FIG. 6A is a flowchart, and FIG. 6B is a gas supply timing chart. In the illustrated example, a gasified metal-containing material is a material A, and a gas containing oxygen or nitrogen is a material B.

  In the ALD, the raw material A is supplied and adsorbed to the substrate (step 1), the raw material A remaining after the adsorption is exhausted (step 2), and after exhausting, the raw material B is supplied to the substrate and reacted with the raw material A. This is a method in which the four steps of forming a film (step 3) and exhausting the raw material B remaining after the film formation are exhausted (step 4), and this is repeated a plurality of times. As shown in FIG. 6B, the gas supply timing is such that the exhaust gas by the purge gas is sandwiched while the raw material A and the raw material B are alternately supplied.

  In MOCVD to which a cycle method is applied, the raw material A is supplied to the substrate, thermally decomposed to form a film on the substrate (step 1), the raw material A remaining after the film formation is exhausted (step 2), and the raw material B is exhausted. This is a method in which the four steps of supplying to the substrate and modifying the deposited film (step 3) and exhausting the raw material B remaining after the modification (step 4) are set as one cycle and this is repeated a plurality of times. As shown in FIG. 6B, the gas supply timing is such that the exhaust gas by the purge gas is sandwiched while the raw material A and the raw material B are alternately supplied.

  In general, the raw material A and the raw material B often have extremely high reactivity, and when these raw materials are supplied simultaneously, the generation of foreign matters due to a gas phase reaction and the deposition of a film with poor film quality occur, leading to a decrease in yield. Become. Therefore, in steps 2 and 4 described above, vacuuming or purging (exhaust) with an inert gas is performed so that the raw material supplied in the previous step does not remain. In particular, the remaining of the raw material in the upstream portion of the substrate directly affects the film forming conditions of the substrate, so that a sufficient purge is necessary. However, if the time required for the purge is long, the throughput decreases.

On the other hand, in the above-described Steps 1 and 3, in both ALD and MOCVD using a cycle method, the supply amount of the raw materials A and B onto the substrate is made uniform, whereby the film thickness formed on the substrate, The uniformity of film quality is improved. Here, the supply amount of the raw material is generally
(Partial pressure of raw material) = (Total pressure) × (Raw material mole fraction) (1)
It is considered as a function of Therefore, if the partial pressure of the raw material is different between the upstream side and the downstream side of the gas flow flowing on the substrate, the amount of adsorption is not uniform, and uniformity cannot be obtained.

  As a semiconductor manufacturing apparatus for carrying out the film forming method, a single-wafer type apparatus has become the mainstream. In order to control the film thickness with high accuracy and to form a high-quality film using a single-wafer apparatus, the gas supply and exhaust methods are important from the viewpoints of film thickness uniformity and throughput described above. The form of gas supply / exhaust to the substrate of the single wafer apparatus can be broadly divided into the following two in terms of configuration.

As shown in FIG. 7A, one form (radial flow type) is a central portion of the substrate surface 43 from the gas supply port 42 above the substrate holding region 41 where the substrate in the processing chamber 50 is held. In this method, the gas is supplied in the vertical direction, is flowed in the radial direction on the substrate surface 43, and the gas is exhausted from the outer periphery of the substrate toward the exhaust port 44.
In another embodiment (single-side flow type), as shown in FIG. 7B, gas is supplied in a direction parallel to the substrate surface 43 from the gas supply port 46 provided on one side of the outside 45 of the substrate holding region. This is a method of supplying and flowing in one direction on the substrate surface 43 and exhausting from an exhaust port 47 provided on the opposite side to the gas supply port 46.

  In the case of the radial flow type of FIG. 7A, an abnormal point where the film thickness is abnormally thick occurs at the center of the substrate where the gas hits, and the film thickness uniformity deteriorates. In order to avoid this, in this embodiment, as shown in FIG. 7C, a perforated plate 48 is installed between the gas supply port 42 and the substrate surface 43, and the gas is shower-like from each hole. It is improved to flow. However, since the gas flow can be biased on a substrate such as a silicon substrate due to the difference in distance from the exhaust port 44, the gas supply to the substrate surface 43 cannot be made uniform, and the uniformity of the film thickness is ensured. Is difficult.

Therefore, various types of radial flow type have been conventionally considered in which the uniformity of the film thickness is improved by adjusting the conductance of the gas exhaust passage. For example, in order to make the flow of the reaction gas uniform over the entire surface of the substrate, the flow cross-sectional area of the exhaust conductance adjustment hole on the side close to the exhaust hole of the baffle plate is made smaller than the opposite side (for example, see Patent Document 1) Equipped with a baffle plate, changing the baffle hole interval, baffle hole diameter, baffle plate wall thickness, slit width, etc., to let the exhaust gas flow out in the radial direction at a uniform flow rate without any deviation over the entire circumference angle of the substrate As described above (for example, see Patent Document 2), by changing the opening distribution of the exhaust passage by moving the baffle plate, the exhaust conductance on the opposite side to the exhaust port is changed, thereby A pressure distribution adjusted (see, for example, Patent Document 3) has been proposed.
JP-A-8-8239 JP 2001-179078 A JP 2003-68711 A

  In the apparatus described in Patent Documents 1 to 3 described above, since the pressure distribution in the processing space is adjusted by the baffle plate, it is possible to improve the film thickness uniformity by equalizing the pressure on the substrate. is there.

  However, since both are of the radial flow type in which the processing gas is supplied by the perforated plate, the region upstream of the perforated plate becomes a high pressure, and it takes time to exhaust the residual gas in the purge process. In addition, the conductance adjustment opening on the side opposite to the exhaust port needs to flow gas in the direction opposite to the exhaust port, so that the residual gas cannot be removed efficiently, and the gas is not baffled. It is conceivable that the particles stay in the lower space or adsorb on the inner wall of the space, which causes the generation of particles. That is, it is considered that the devices described in Patent Documents 1 to 3 cannot perform quick exhaust and the purge efficiency is deteriorated.

In a process that requires a high purge efficiency when the purge efficiency is poor, for example, a cycle process such as ALD that frequently purges or MOCVD using a cycle method, exhaust of residual gas in steps 2 and 4 of the film forming method described above. Takes time, which causes a reduction in throughput. In order to shorten the exhaust time, it is considered to reduce the processing space volume by reducing the interval between the porous plate and the substrate. However, when the processing space volume is reduced, the pores of the porous plate are formed on the substrate. As a result, it becomes difficult to ensure film thickness uniformity.
Therefore, this radial sink type has been difficult to apply to cycle processing.

  Therefore, for the application of the single wafer type apparatus to the cycle processing, a single-sided flow type with better purge efficiency than the radial flow type is often selected. However, in the case of the one-side flow type, although the purge efficiency is good, a pressure difference is inevitably generated on the substrate, so that the pressure distribution on the substrate cannot be effectively controlled.

  An object of the present invention is to solve the above-mentioned problems of the prior art in a substrate processing apparatus of the type that exhausts gas from the side opposite to the gas supply side while supplying gas from the side of the substrate. An object of the present invention is to provide a substrate processing apparatus capable of effectively controlling the pressure distribution.

  According to a first aspect of the present invention, there is provided a processing chamber for processing a substrate, a holder for holding the substrate in the processing chamber, and a supply that is provided on the side of the substrate and above the substrate to supply gas to the substrate. An inner surface of the processing chamber facing the substrate, and an exhaust port provided on the opposite side of the substrate and below the substrate and exhausting the processing chamber. The substrate processing apparatus is configured to be inclined with respect to the substrate.

  A gas supplied from the side of the substrate into the processing chamber flows in one direction on the substrate and is exhausted from an exhaust port below the substrate. According to the present invention, since the processing chamber wall surface facing the substrate is configured to be inclined with respect to the substrate, the gas flow velocity distribution on the substrate can be adjusted according to the degree of inclination of the processing chamber wall surface. The pressure distribution on the substrate can be effectively controlled.

  An example of the substrate is a silicon substrate. As a method for processing a substrate, MOCVD using ALD or a cycle method in which a film is deposited by alternately supplying two or more gases, or a normal MOCVD in which a film is deposited by simultaneously supplying two or more gases. Etc. Examples of processing contents of the substrate include formation of a metal oxide film. A single wafer type is mentioned as a processing chamber. Examples of the holder include a susceptor that heats the substrate to be held. Examples of the gas include a metal-containing raw material and a gas containing oxygen or nitrogen. Examples of the substrate processing apparatus include a semiconductor manufacturing apparatus having a single wafer processing chamber.

According to a second invention, in the first invention, the distance between the inner wall surface of the processing chamber facing the substrate and the substrate is larger on the downstream side than on the upstream side of the gas flow. A substrate processing apparatus, wherein an inner wall surface of a processing chamber is configured to be inclined with respect to the substrate.
When the gas flows in one direction on the substrate, the pressure on the upstream side tends to be higher than the downstream side on the substrate, but according to the present invention, the inner wall surface of the processing chamber facing the substrate. Is configured to be inclined with respect to the substrate such that the distance between the substrate and the substrate is greater on the downstream side than on the upstream side of the gas flow, so that the gas can flow more easily to the downstream side. Since the pressure on the upstream side decreases and the pressure on the downstream side increases, the tendency for the pressure on the upstream side to be higher can be alleviated. Therefore, the pressure distribution on the substrate is made uniform, and the uniformity of substrate processing is improved.

  According to a third aspect of the present invention, there is provided a process of carrying a substrate into the processing chamber, and supplying the gas to the substrate from the side of the substrate carried into the processing chamber from above and sandwiching the substrate. And a step of processing the substrate by exhausting from below the substrate, and a step of unloading the processed substrate from the processing chamber. In the substrate processing step, the flow rate of the gas on the substrate The semiconductor device manufacturing method is characterized in that the distribution is adjusted.

  In the substrate processing step, the gas supplied from the side of the substrate into the processing chamber flows in one direction on the substrate and is exhausted from an exhaust port below the substrate. According to the present invention, since the flow velocity distribution of the gas on the substrate is adjusted, the pressure distribution on the substrate can be effectively controlled.

  According to the present invention, since the pressure distribution on the substrate can be effectively controlled, the processing amount on the substrate can be adjusted, and the uniformity of the substrate processing can be ensured.

Embodiments of the present invention will be described below.
FIG. 1 is a longitudinal sectional view of a single wafer processing apparatus according to an embodiment.

  As shown in FIG. 1, the substrate processing apparatus includes, for example, a flat processing chamber 1 that processes a single substrate 8 in a substantially horizontal position, and a gas supply port that supplies gas to the substrate 8 in the processing chamber 1. 19, 20, the exhaust port 16 for exhausting the inside of the processing chamber 1, the susceptor 3 as a holder for holding the substrate 8 substantially horizontally, and the gas in the space 33 below the substrate 8, that is, below the susceptor 3. And a discharge port 11 for discharging water.

  The processing chamber 1 is constituted by an upper container 26 and a lower container 27, and is configured to process the substrate 8 in a sealed internal space.

The upper container 26 functions as a lid that covers the opening of the lower container 27, and the inner wall surface of the lid is not flat but inclined. In other words, the upper inner wall surface (hereinafter referred to as the upper container upper inner wall surface) 26a of the upper container 26 as the inner wall surface of the processing chamber facing the surface of the substrate 8 held by the susceptor 3 is an inclined surface.
As shown in the figure, the inclined surface of the upper container upper inner wall surface 26a gradually increases the facing distance between the substrate 8 and the upper container upper inner wall surface 26a from the upstream side to the downstream side of the gas flow indicated by the arrow. It is composed of an inclined surface.

  The upper container 26 is provided with a plurality of supply ports for supplying gas to the substrate 8, for example, two gas supply ports 19 and 20. The gas supply ports 19 and 20 are provided not on the substrate 8 but on the side of the susceptor 3 on the side of the substrate 8 and above the surface level of the susceptor 3 above the substrate 8. . As shown in the figure, the perforated plate 48 of the conventional single wafer apparatus is not installed between the gas supply ports 19 and 20 and the substrate 8.

The gas supply ports 19 and 20 communicate with a space 34 above the substrate 8, that is, above the susceptor 3 in the processing chamber 1. The gas supply port 19 is configured to selectively supply the first reaction gas or the purge gas into the processing chamber 1. The gas supply port 20 is provided adjacent to the gas supply port 19 and is configured to selectively supply the second reaction gas or purge gas into the processing chamber 1. Two lines for supplying gas are connected to the gas supply ports 19 and 20, respectively. One system is a TMA supply line 4 for supplying TMA (Al (CH ₃ ) ₃ : trimethylaluminum) which is an organic liquid raw material of a metal oxide film, for example, an aluminum oxide film, and the other system is, for example, reactive with the raw material. It is the water supply line 5 which supplies the water which is high gas.

The TMA supply line 4 is provided with a liquid flow rate control means 22 that controls the flow rate of the TMA liquid that is liquid at room temperature, a vaporization means 23 that vaporizes the TMA liquid whose flow rate is controlled, and a valve 9 that opens and closes the TMA supply line 4. An Ar supply line 17 is connected between the vaporization means 23 of the TMA supply line 4 and the valve 9, and Ar gas whose flow rate is controlled by the flow rate control means 21 is supplied to the TMA supply line 4 via the valve 12. It is configured so that it can be supplied.
With this configuration, the following three types of gas introduction into the gas supply port 19 can be selected. (1) By opening the valve 9 of the TMA supply line 4 and closing the valve 12 of the Ar supply line 17, only the TMA gas vaporized by the vaporizing means 23 is introduced from the TMA supply line 4 to the gas supply port 19 alone. . (2) Further, by opening the valve 12 of the Ar supply line 17, a mixed gas of TMA gas and Ar gas is introduced from the TMA supply line 4 to the gas supply port 19. (3) Stop the TMA gas from the vaporization means 23 and introduce only the Ar gas from the TMA supply line 4 into the gas supply port 19 alone.

The water supply line 5 is provided with a liquid flow rate control means 24 for controlling the flow rate of water, a vaporization means 25 for vaporizing the flow-controlled water, and a valve 10 for opening and closing the water supply line 5. Between the vaporization means 25 of the water supply line 5 and the valve 10, the Ar supply line 17 described above is branched and connected by a branch line 17 a, and the Ar gas whose flow rate is controlled by the flow rate control means 21 is passed through the valve 13. The water supply line 5 can be supplied.
With this configuration, the following three types of gas introduction into the gas supply port 20 can be selected. (1) By opening the valve 10 of the water supply line 5 and closing the valve 13 of the branch line 17a, only the water vapor vaporized by the vaporizing means 25 is introduced from the water supply line 5 into the gas supply port 20 alone. (2) Further, the mixed gas of water vapor and Ar gas is introduced from the water supply line 5 to the gas supply port 20 by opening the valve 13 of the branch line 17a. (3) Stop the water vapor from the vaporization means 25 and introduce only Ar gas from the water supply line 5 into the gas supply port 20 alone.

  An exhaust port 16 is provided on one side wall of the lower container 27. The exhaust port 16 is open to a space 33 below the susceptor 3 on the opposite side of the gas supply ports 19 and 20 and sandwiching the substrate 8 held substantially horizontally from the substantially horizontal direction. is doing. As a result, the exhaust port 16 communicates with the exhaust port 11 via the space 33 below the susceptor 3. The exhaust port 16 is connected to a gas exhaust line 6 as an exhaust pipe provided with a pressure control means 15 and a vacuum pump 37 to exhaust the atmosphere in the processing chamber 1. The inside of the processing chamber 1 can be controlled to a predetermined pressure by the pressure control means 15. The pressure control means 15 may not be used.

A substrate loading / unloading port 30 is provided on the other side wall facing the one side wall of the lower container 27. A gate valve 7 is provided at the opening of the extending portion extending outward from the substrate loading / unloading port 30, and the substrate 8 is transferred from the substrate loading / unloading port 30 via the gate valve 7 by the transfer robot 38 as transfer means. 1 can be conveyed in and out.
The upper container 26 and the lower container 27 are made of a metal such as aluminum or stainless steel, for example. In addition, plate-like or fiber-like heaters 31 are provided on the upper container 26, the lower container 27, the extending portion of the substrate loading / unloading port 30, and the outer periphery of the gas exhaust line 6, so that these container walls can be heated to a predetermined temperature. It has become.

The susceptor 3 is provided in the processing chamber 1, has a disk shape, and is configured to hold the substrate 8 thereon. The susceptor 3 includes a heater 55 such as a ceramic heater and is configured to heat the substrate 8 to a predetermined temperature. The susceptor 3 includes a support shaft 29. The support shaft 29 is inserted in a vertical direction through a through hole 28 provided in the center of the bottom of the lower container 27 of the processing chamber 1, and the susceptor 3 is moved up and down by an elevating mechanism 56. A film forming process is performed at a film forming position (illustrated position) where the susceptor 3 is located above, and the substrate 8 is transferred at a lower standby position. When the susceptor 3 is in the above-described film forming position, the space 8 above the susceptor 3 and the space 33 below the susceptor 3 are formed in the processing chamber 1 by the substrate 8 and the susceptor 3 that partition the inside of the processing chamber 1 up and down. It is formed in the upper and lower sides.
The susceptor 3 is made of, for example, quartz, carbon, ceramics, silicon carbide (SiC), aluminum oxide (Al ₂ O ₃ ), aluminum nitride (AlN), or the like.

  The discharge port 11 discharges gas from the space 34 above the susceptor 3 to the space 33 below the susceptor 3. The discharge port 11 is continuously provided on the outer periphery of the susceptor 3. That is, the discharge port 11 is formed as a ring-shaped gap between the processing chamber wall 32 and the outer periphery of the susceptor 3. In the embodiment, the ring-shaped gaps are formed at equal intervals over the entire circumference. Of the exhaust ports 11, the exhaust port located on the upstream side of the gas flow is referred to as an upstream exhaust port 11 </ b> A, and the exhaust port located on the downstream side is referred to as a downstream exhaust port 11 </ b> B. The outlet located on the middle stream side is referred to as the middle stream outlet.

As shown in the figure, in the processing chamber wall 32 directly below the gas supply ports 19 and 20 in the processing chamber wall 32, a protruding inner wall 32a protruding inward is provided at a location flush with the susceptor surface. A discharge port 11A on the upstream side is provided between the inner wall 32a and the outer peripheral portion of the susceptor 3 facing the protruding inner wall 32a.
Therefore, the gas that has flowed from the gas supply ports 19 and 20 into the space 34 above the susceptor 3 in the processing chamber 1 collides with the projecting inner wall 32a, and its route is changed, and a part thereof is the upstream discharge port 11A. Flows into the space 33 below the susceptor 3 and flows in one direction toward the exhaust port 16 below the substrate. The rest flows in one direction on the substrate 8 toward the exhaust port 16 as indicated by arrows.

In this way, by providing the protruding inner wall 32a that flows the gas directly under the gas supply ports 19 and 20, the gas supply ports 19 and 20 are provided in the upper part of the upper container 26 of the processing chamber 1, The gas supplied to the space 34 above the susceptor 3 can flow in parallel on the substrate 8.
Then, the gas flows on the substrate 8 and passes through the downstream susceptor 3 and is discharged from the downstream discharge port 11B into the space 33 below the susceptor 3, and the space 33 below the upstream discharge port 11A. The gas discharged into the interior and flowing below the susceptor 3 joins at the exhaust port 16 and is exhausted from the gas exhaust line 6.

Since the upstream discharge port 11A is provided downstream of the gas supply ports 19 and 20 and upstream of the substrate 8, a large amount of purge gas is discharged from the discharge port 11A below the susceptor 3. The space 33 can be discharged smoothly and the purge efficiency is further improved. Further, since the gas supply ports 19 and 20 are provided on the side of the susceptor 3, the gas discharged from the upstream discharge port 11 </ b> A to the space 33 below the susceptor 3 is discharged from the uppermost stream of the space 33. Since it can be made to flow in, purge efficiency improves more.
Further, gas is supplied from the side of the substrate 8 to the substrate 8 without using the porous plate and exhausted from the side opposite to the supply side, so the gas is supplied from the porous plate provided above the substrate to the substrate. Compared with the one that supplies gas in a shower form, the upstream side of the gas supply ports 19 and 20 does not become excessively high in pressure, and the residual gas can be exhausted quickly.

  As described above, the substrate processing apparatus of the embodiment is configured.

  Next, a method of processing a substrate will be described as one step of manufacturing a semiconductor device using the substrate processing apparatus described above. Here, a process for forming an aluminum oxide film on a silicon substrate will be described as an example. The film forming method uses ALD in which a metal raw material and a gas containing oxygen or nitrogen are alternately supplied to deposit a film. Further, TMA that is liquid at room temperature is used as the metal-containing raw material, and water is used as the gas containing oxygen or nitrogen.

  In the substrate processing, first, the susceptor 3 is lowered to the standby position, and then the gate valve 7 is opened. A single silicon substrate 8 is carried into the processing chamber 1 via the substrate loading / unloading port 30 by the transfer robot 38, and transferred and held on the susceptor 3. After the gate valve 7 is closed, the susceptor 3 is raised to a predetermined film formation position by the elevating mechanism 56. The susceptor 3 is heated by the heater 55 controlled by the temperature control means 14, and the substrate 8 is heated for a predetermined time. The inside of the processing chamber 1 is evacuated by a vacuum pump 37, and the inside of the processing chamber 1 is controlled to a predetermined pressure by the pressure control means 15. After the substrate 8 is heated to a predetermined temperature and the pressure is stabilized, film formation on the substrate 8 is started. The film formation is composed of the following four steps, and the four steps are defined as one cycle, and are repeated a plurality of cycles until a film having a desired thickness is formed.

  In step 1, the valve 9 is opened, the liquid raw material TMA whose flow rate is controlled by the liquid flow rate control means 22 is supplied to the vaporization means 23, and the TMA gas as the first reaction gas vaporized by the vaporization means 23 is supplied. The TMA supply line 4 is supplied into the processing chamber 1 through the gas supply port 19. When diluting the TMA gas, the valve 12 is further opened, the Ar gas whose flow rate is controlled by the flow rate control means 21 is caused to flow from the Ar supply line 17 to the TMA supply line 4, and the TMA gas mixed with the Ar gas is The gas is supplied from the TMA supply line 4 through the gas supply port 19 into the processing chamber 1. TMA gas is supplied onto the substrate 8 and adsorbed on the surface thereof. Excess gas (TMA gas) is discharged from a discharge port 11 provided on the outer periphery of the susceptor 3 to a space 33 below the susceptor 3, flows through the space 33 in the direction of the arrow in the figure, and is discharged from the exhaust port 16. .

  In step 2, the supply of TMA gas from the vaporizing means 23 is stopped while the valve 9 is kept open. At this time, when the valve 12 is closed, it is opened. The Ar gas whose flow rate is controlled by the flow rate control means 21 flows from the Ar supply line 17 to the TMA supply line 4 and is supplied into the processing chamber 1 through the gas supply port 19, and into the TMA supply line 4 and the processing chamber 1. The remaining TMA gas is replaced with Ar gas and exhausted from the exhaust port 16.

In step 3, both the valves 9 and 12 are closed, and the valve 10 is opened instead. Water whose flow rate is controlled by the liquid flow rate control means 24 is supplied to the vaporization means 25, and water vapor (H ₂ O) is supplied into the processing chamber 1 from the water supply line 5 through the gas supply port 20. Alternatively, the valve 13 is opened, the carrier gas Ar whose flow rate is controlled by the flow rate control means 21 is caused to flow from the Ar supply line 17 to the water supply line 5, and water vapor mixed with Ar gas is supplied from the water supply line 5 to the gas supply port. 20 is supplied into the processing chamber 1 through 20. On the substrate 8, the TMA adsorbed in the step 1 and the water vapor react to form an aluminum oxide film. Excess gas (water vapor) and by-products are discharged from a discharge port 11 provided on the outer periphery of the susceptor 3 to a space 33 below the susceptor 3, and flow through the space 33 in the direction of the arrow in the figure to discharge the exhaust port 16. Exhausted from.

  In step 4, the supply of water vapor from the vaporizing means 25 is stopped while the valve 10 is kept open. When the valve 13 is closed, it is opened. Ar gas whose flow rate is controlled by the flow rate control means 21 flows from the Ar supply line 17 to the water supply line 5 and is supplied into the processing chamber 1 through the gas supply port 20, and into the water supply line 5 and the processing chamber 1. The remaining water vapor and by-products are replaced with Ar gas and exhausted from the exhaust port 16.

  The time required for the above steps 1 to 4 is preferably 1 second or less in each step in order to improve throughput. These four steps are set as one cycle, and this is repeated a plurality of times to form an aluminum oxide film having a desired film thickness on the substrate 8. After film formation, the susceptor 3 is lowered to the standby position by the elevating mechanism 56. The substrate 8 after the film forming process is carried out of the processing chamber 1 by the transfer robot 38 via the gate valve 7.

  As the range of the above processing conditions, the substrate temperature: 200 to 500 ° C., the processing chamber pressure: 13.3 to 1330 Pa (0.1 to 10 Torr), the total flow rate of the carrier gas and the reaction gas (the first reaction gas, the first reaction gas) Common to 2 reaction gases): 0.1-2 slm, film thickness: 1-5 nm are preferable.

  The substrate temperature and the processing chamber pressure in each process are controlled by the temperature control means 14 and the pressure control means 15, respectively. The temperature control unit 14, the pressure control unit 15, the valves 9, 10, 12 and 13, the vaporization units 23 and 25, and the flow rate control units 21, 22 and 24 are integrated and controlled by the control unit 40.

  According to the present embodiment, the facing distance between the surface of the substrate 8 and the upper container upper inner wall surface 26a gradually increases from the upstream side to the downstream side of the gas flow of the upper container upper inner wall surface 26a. Because of such an inclined surface, in steps 1 and 3 described above, a film with good film thickness uniformity can be formed on the substrate 8 as described below.

  When the facing distance between the surface of the substrate 8 and the upper inner wall surface 26a of the upper container increases toward the downstream side, the gas easily flows to the downstream side, and the amount of gas stays on the downstream side increases. Pressure rises. On the other hand, on the upstream side, the amount of staying gas is relatively small, and the pressure on the substrate 8 is reduced. Therefore, the flow velocity distribution of the gas on the substrate 8 can be adjusted according to the degree of inclination of the upper inner wall surface 26a of the upper container, and the pressure distribution on the substrate 8 can be controlled. As in the illustrated example, the inclined surface of the upper inner wall surface 26a of the upper container is inclined such that the facing distance between the substrate 8 and the upper inner wall surface 26a of the upper container gradually increases from the upstream side to the downstream side of the gas flow. If the surface is configured, the gas can easily flow to the downstream side, and the pressure distribution on the substrate 8 is relaxed from becoming a high pressure on the upstream side, so that the TMA gas and water vapor supplied onto the substrate 8 can be reduced. The pressure distribution becomes uniform. TMA gas and water vapor are adsorbed on the substrate 8 under the uniform pressure distribution.

  Experimental and theoretical considerations regarding this adsorption have shown that when the temperature is constant between a surface and a gas molecule, the amount of adsorption is expressed by the pressure in the gas phase. Therefore, in steps 1 and 3, since the pressure distribution on the substrate is made uniform, the amount of gas adsorbed on the substrate is made uniform, and a film with good film thickness uniformity can be formed on the substrate. In addition, the yield of the semiconductor device can be improved.

  The above-described effect of uniforming the pressure distribution is particularly effective when a thin film is formed on the substrate 8 by ALD in which a gas flows in one direction with respect to the substrate 8. This is because if the flow rate of the reaction gas supplied to the substrate 8 is increased, a pressure difference inevitably occurs on the substrate 8, but this pressure difference can be eliminated.

  In addition, although ALD was demonstrated in embodiment, it cannot be overemphasized that this invention can be utilized also in normal MOCVD which deposits a film | membrane by supplying two or more types of gas simultaneously and MOCVD which applied the cycle method. Absent.

  In the above-described embodiment, the “reactive gas” is a metal-containing raw material as a first raw material and a compound and an element as a second raw material capable of reacting with this. As specific metal-containing raw materials (first raw materials), in addition to the exemplified TMA gas containing Al, Si, Ti, Sr, Y, Zr, Nb, Ru, Sn, Ba, La, Hf, Ta, Ir , Pt, W, Pb, and Bi.

Further, the compound and element (second raw material) may be a suitable non-metallic reactant, that is, a gas containing oxygen or nitrogen such as water, oxygen, ammonia or the like, but sometimes a radical activated by some method. There is also a case of ion. Moreover, although it does not actually react with the metal-containing raw material, it may give energy to the self-decomposition reaction of the metal-containing raw material. For example, it may be a rare gas or an inert gas activated by plasma or the like. Specifically, as the gas containing oxygen or nitrogen, in addition to the exemplified H ₂ O, O ₂ , O ₃ , NO, N ₂ O, H ₂ O ₂ , N ₂ , NH ₃ , N ₂ H ₆ And any of these radical species or ionic species generated by activating any of them with an activating means.

  The “purge gas” is supplied to the processing chamber 1 to remove unnecessary reactants other than the reactant adsorbed on the substrate 8, or when two different groups of reactant gases are located outside the surface of the substrate 8. Used to prevent mixing and reaction. As the purge gas, in addition to the exemplified Ar shared with the carrier gas, other rare gases and inert gases such as nitrogen gas are used.

Next, the influence of the inclination of the upper container upper inner wall surface 26a described above on the uniformity of the pressure distribution (raw material partial pressure distribution) on the substrate is analyzed, and the opposing distance between the substrate 8 and the upper container upper inner wall surface 26a. It is verified that the uniformity of the raw material partial pressure distribution on the substrate is improved by configuring the inclined surface so as to increase from the upstream side to the downstream side of the gas flow.
In Steps 1 and 3, good in-plane film thickness uniformity can be obtained by uniformly supplying and adsorbing the reaction gas to the substrate. Of Steps 1 and 3, the adsorption in Step 1 is particularly important. Since the reactivity between TMA and water vapor (H ₂ O) is high, if H ₂ O is sufficiently supplied in Step 3, all of the TMA adsorbed on the substrate reacts to form a film. Therefore, it is important to uniformly adsorb TMA on the substrate. For this reason, the verification was performed for step 1. However, here, for convenience, the data value of water vapor is used instead of TMA.

  A method for analyzing the pressure distribution on the substrate will be described with reference to FIGS. 2 and 3 are cross-sectional views of the processing chamber having the upper container upper inner wall surface 26a used in this analysis. In FIG. 2, the entire upper container upper inner wall surface 26a is inclined so that the distance between the upstream substrate surface and the upper container upper inner wall surface 26a (hereinafter simply referred to as upstream gap) Gu is narrow, The distance Gd between the substrate surface on the side and the upper inner wall surface 26a of the upper container (hereinafter simply referred to as the downstream gap) Gd is widened. In FIG. 3, the upper container upper inner wall surface 26 a is inclined so that the gap becomes wider from the upstream to the middle flow, and the distance between the substrate surface on the middle flow side and the upper container upper inner wall surface 26 a from the middle flow to the downstream. Gm to downstream gap Gd (hereinafter, simply referred to as a midstream gap) are flat at equal intervals.

Regarding the shapes of the four types of upper container upper inner wall surface 26a shown in FIG. 4, the pressure distribution on each substrate was obtained using 3D thermal fluid analysis software manufactured by Fluent. Four types of upper container upper inner wall surface shapes No. 1 to No. 4 have the upstream gap Gu fixed at 21 mm and the downstream gap Gd increased to 21 mm, 30 mm, 40 mm, and 40 mm (from midstream to downstream). It has been changed to. Upper container upper inner wall surface shape No. In the case of 1, it is flat and both the upstream gap Gu and the downstream gap Gd are equally spaced with 21 mm. In the case of the upper container upper inner wall surface shape No. 2 to No. 3, as shown in FIG. 2, the entire upper surface of the processing chamber is inclined, and the upstream side gap Gu is fixed as narrow as 21 mm, and the downstream side The gap Gd is widened to 30 mm and 40 mm. In the case of the upper container upper inner wall surface shape No. 4, as shown in FIG. 3, the upstream gap Gu is 21 mm and the middle flow gap Gm is 40 mm. The downstream is flat at an equal interval of 40 mm.
The analysis conditions were as follows: substrate diameter: 300 mm, substrate temperature: 300 ° C., processing chamber exhaust pressure (measured value by pressure control means 15 in the vicinity of the exhaust port 16): 13 Pa, Ar gas flow rate: 1 slm, raw material mole fraction: 0.0266 (raw material flow rate 0.0266 slm≈1 slm × 0.027) and container wall temperature by heater 31: 100 ° C.

FIG. 5 is a diagram showing the relationship of the raw material partial pressure on the substrate obtained in this analysis. From FIG. 5, in all four types of shapes, the raw material partial pressure tends to be higher on the upstream side and lower on the downstream side, and as the downstream gap Gd becomes wider with respect to the upstream gap Gu that is fixed while being narrow, The uniformity of the raw material partial pressure distribution is improved. The uniformity of the raw material partial pressure distribution of the upper container upper inner wall surface shape No. 1 to No. 4 is 6.6%, 4.9%, 3.6%, 2.4%. It can be seen that, among all the shapes, the upper container upper inner wall surface shape No. 4 has the best uniformity of the raw material partial pressure distribution.
In other words, the pressure on the upstream side of the gas is increased by increasing the opposing distance between the substrate and the inner wall surface of the processing chamber from the upstream side toward the downstream side so that the gas can flow more easily downstream. It is possible to relieve the tendency and relieve the tendency of the pressure on the gas downstream side to decrease. Therefore, the uniformity of the pressure distribution in the substrate surface can be improved by optimizing the inclination of the upper inner wall surface of the upper container.

In FIG. 5, the set value of the raw material partial pressure in the vicinity of the center position of the substrate (substrate position 0 m) is set to 0.44 Pa. This partial pressure value can be obtained as follows. When the processing chamber exhaust pressure is controlled to be 13 Pa, the estimated value of the total pressure in the vicinity of the center position of the substrate is about 16.5 Pa. Since the raw material mole fraction is 0.0266, from the formula (1),
0.44 Pa≈16.5 Pa × 0.0266
It becomes.

  From the above analysis results, the upper inner wall surface of the upper container is inclined so that the facing distance between the substrate and the upper inner wall surface of the upper container is larger on the downstream side than on the upstream side. It was verified that the uniformity of pressure distribution was improved.

It is a longitudinal cross-sectional view of the processing chamber of the substrate processing apparatus in an embodiment. It is explanatory drawing which made the shape in which the upper inner wall surface of the upper container used for the analysis of the pressure distribution on a board | substrate inclined in the whole. It is explanatory drawing which the upper container upper inner wall surface used for the analysis of the pressure distribution on a board | substrate inclined to the middle stream, and the downstream is flat shape. It is explanatory drawing which shows the shape of four types of upper container upper inner wall surfaces. It is a characteristic view which shows the raw material partial pressure distribution on the board | substrate by four types of upper container upper inner wall surface shapes calculated | required by this analysis. It is explanatory drawing of the gas supply method common to ACVD and MOCVD which applied the cycle method, (a) is a flowchart, (b) is a time chart of gas supply. It is explanatory drawing which shows the gas supply / exhaust form to the board | substrate of a common single wafer apparatus, Comprising: (a) is radial flow type, (b) is a single-side flow type, (c) is an improved radial flow type Respectively.

Explanation of symbols

1 Processing chamber 3 Susceptor (holding tool)
8 Substrate 16 Exhaust port 19, 20 Gas supply port 26 Upper container 26a Upper inner wall surface of upper container (inner wall surface of processing chamber)

Claims (2)

A processing chamber for processing the substrate;
A holder for holding the substrate in the processing chamber;
A supply port provided on the side of the substrate and above the substrate to supply gas to the substrate;
An exhaust port that is provided on the opposite side of the supply port and the substrate and below the substrate and exhausts the processing chamber;
A substrate processing apparatus, wherein an inner wall surface of the processing chamber facing the substrate is inclined with respect to the substrate.   The inner wall surface of the processing chamber is inclined with respect to the substrate so that the distance between the inner wall surface of the processing chamber facing the substrate and the substrate is larger on the downstream side than on the upstream side of the gas flow. The substrate processing apparatus according to claim 1, wherein the substrate processing apparatus is configured to do so.

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