JP5145792B2 - Single wafer heat treatment apparatus and heat treatment method - Google Patents

Description

  The present invention relates to a single-wafer type heat treatment apparatus and a heat treatment method for heating an object to be heated by a heating lamp while flowing a gas in a chamber, and in particular, a silicon single crystal wafer 1 in an inert gas atmosphere such as argon. The present invention relates to a single wafer heat treatment apparatus and a heat treatment method for performing rapid heating / cooling treatment on a sheet.

  In a process of manufacturing a semiconductor wafer used for manufacturing a device device, a silicon single crystal wafer may be subjected to rapid heating / rapid cooling heat treatment (so-called RTA process: Rapid Thermal Annealing).

For example, a silicon wafer manufactured by the CZ (Czochralski) method contains a large amount of oxygen impurities, and these oxygen impurities become oxygen precipitates (BMD: Bulk Micro Defect) that cause dislocations and defects. If such oxygen precipitates are present on the surface where the device is formed, the leakage current increases and the breakdown voltage of the oxide film decreases, which greatly affects the characteristics of the semiconductor device. Therefore, in Patent Document 1, when a BMD layer having a high-quality DZ layer (defect-free layer) on the wafer surface layer portion and having a gettering effect is formed on the bulk portion, a resistance heating type heat treatment furnace is used. It is disclosed that after the heat treatment, the heat treatment is performed using a rapid heating / cooling apparatus.
Other than these processes, RTA treatment is often applied to the wafer in the wafer manufacturing process.

The RTA process is generally performed for each wafer and is performed by a single wafer heat treatment apparatus as shown in FIG. FIG. 5 is a schematic view of a conventional single wafer heat treatment apparatus.
The heat treatment apparatus 51 for RTA treatment has a chamber 52 made of quartz, and heats the wafer W in the chamber 52. Heating is performed by heating lamps 55 disposed above and below the chamber 52. The lamps can control the power supplied independently.
The heat treatment apparatus 51 also includes a gas supply unit 53 for supplying the atmospheric gas G into the chamber 52 and a gas discharge unit 54 for discharging the atmospheric gas G. The chamber 52 is provided with a loading / unloading port 57 for loading / unloading the wafer W, and a shutter 58 can cover the loading / unloading port 57. The wafer W is then placed on a quartz susceptor 56 on which a three-point support is formed, and is subjected to RTA processing.
Further, a special window for temperature measurement (not shown) is provided in the chamber 52, and the temperature of the wafer W during the RTA process is measured through the special window by a pyrometer (not shown) installed outside the chamber 52. 52 can be measured from the outside.

In order to perform the RTA process on the wafer W using such a heat treatment apparatus 51, first, the silicon single crystal wafer W is put into the chamber 52 from the loading / unloading port 57 by the wafer handling apparatus (not shown), and is placed on the susceptor 56. After the placement, the shutter 58 is closed.
Then, after sufficiently purging with nitrogen gas, while supplying hydrogen, argon, or a mixed gas such as nitrogen and oxygen as the atmospheric gas G from the gas supply unit 53, power is supplied to the heating lamp 55 to bring the wafer W to the target temperature. The temperature rises to Then, after a high temperature heat treatment is applied to the wafer W at this desired temperature for a predetermined time, the output of the lamp 55 is lowered to lower the temperature of the wafer W, the wafer W is taken out by the wafer handling device, and the RTA process is completed.

  When the RTA process is performed on the wafer W in an inert gas using such a conventional heat treatment apparatus, if the process temperature is, for example, a high temperature of 1000 ° C. or higher, the purge time is set to be long in units of hours, Even when a gas with a sufficiently reduced impurity concentration was used, surface roughness occurred on the surface of the wafer taken out after the high temperature RTA treatment. When the surface roughness of the wafer was measured with an AFM (Atomic Force Microscope), the roughness of the wafer whose surface roughness was adjusted by polishing before the RTA process sometimes increased after the RTA process. Since this uses an inert gas, it has been suggested that SiO is vaporized from the surface of the quartz chamber at a high temperature and adheres to the surface of the wafer W to be heated and reacts.

  Therefore, generally, a method of suppressing surface roughness by adding hydrogen to an atmospheric gas such as argon has been adopted, but it has often not been a very effective measure depending on the type of wafer. Further, when hydrogen gas is added to an inert gas such as argon, there are problems such as metal contamination of the wafer and occurrence of slip dislocation. Furthermore, since hydrogen gas is handled, sufficient care is required for handling it for the safety of the RTA treatment work.

JP 2002-43318 A

  The present invention has been made in view of such problems. For example, an object to be heated such as a silicon single crystal wafer is subjected to a heat treatment of rapid heating / cooling at a high processing temperature of, for example, 1000 ° C. or higher. An object of the present invention is to provide a single wafer heat treatment apparatus and a heat treatment method that can easily and safely suppress occurrence of surface roughness on the surface of an object to be heated.

In order to achieve the above object, the present invention comprises at least a quartz chamber for containing an object to be heated,
A gas supply unit for supplying gas into the chamber from one end of the chamber;
A gas discharge unit for discharging the gas supplied from the gas supply unit from the other end of the chamber;
A heating lamp for heating the object to be heated disposed outside the chamber;
In a single wafer type heat treatment apparatus that heats the object to be heated while flowing gas in the chamber,
The gas supply unit is at least
A central supply port for supplying gas to the central portion side of the chamber;
An outer peripheral supply port that is located on the outer periphery of the central supply port and supplies gas along the inner wall of the chamber;
That provides a heat treatment apparatus for single wafer, characterized in that in which the heat treatment on the object to be heated while supplying the gas from the outer peripheral supply port and said central feed port.

In the present invention, at least an object to be heated is accommodated in a quartz chamber,
Gas is supplied into the chamber from a gas supply unit located at one end of the chamber, and the gas is flowed into the chamber by discharging the supplied gas through a gas discharge unit located at the other end of the chamber,
In the heat treatment method of performing a heat treatment on the object to be heated by a heating lamp disposed outside the chamber,
When supplying gas into the chamber from the gas supply unit, a gas is supplied along the inner wall of the chamber located at the outer periphery of the central supply port and the central supply port for supplying gas to the central portion side of the chamber wherein while supplying gas from the outer peripheral supply port that provides heat treatment wherein the heat treatment in the object to be heated.

  As described above, the present invention provides a single supply type heat treatment apparatus that heats an object to be heated while flowing a gas in a chamber, wherein the gas supply unit supplies at least a gas to the central part side of the chamber. And an outer peripheral supply port for supplying gas along the inner wall of the chamber located on the outer periphery of the central supply port, and when supplying gas into the chamber from the gas supply unit, Gas is supplied from an outer peripheral supply port that supplies gas along the inner wall of the chamber.

Thereby, even if SiO is vaporized from the quartz chamber surface during the RTA process, a gas flow can be created in the chamber by the central supply port and the outer peripheral supply port so that the vaporized SiO does not adhere to the object to be heated. Therefore, during the RTA treatment, particularly in a high-temperature heat treatment, SiO vaporized from the chamber surface can be easily suppressed by only the gas flow. Therefore, surface roughness of the object to be heated during the RTA process can be prevented, and the object to be heated can maintain a desired roughness even when the RTA process is performed.
In addition, since the surface roughness of the surface of the object to be heated can be suppressed only by the gas flow, the hydrogen gas used as a countermeasure against the surface roughness of the object to be heated is not necessarily handled. The gas can be 100% inert gas, and metal contamination and slip dislocation of the heated object due to the addition of hydrogen gas do not occur.

In this case, the gas supply unit, said central feed port and the it is rather preferable flow rate of the gas supplied from the outer peripheral supply ports are those that can be individually controlled, also, from the outer peripheral supply port and said central feed port it preferred to control individually the flow rate of the gas supplied.

  Thus, by individually controlling the flow rate of the gas supplied from the central supply port and the outer peripheral supply port, the vaporized SiO adheres to the object to be heated in accordance with the size of each gas supply port. A gas flow that does not occur can be created easily.

Then, the area ratio of the central feed port and the outer peripheral supply port 3: 1 it is not preferable.
As described above, since the area ratio of the central supply port and the outer peripheral supply port for supplying the gas is 3: 1, the gas supplied from the outer peripheral supply port passing near the inner wall of the chamber is supplied from the central supply port. It is possible to create a gas flow layer having a sufficient thickness so that the gas does not hit the inner wall of the chamber.

Further, the flow rate of the gas supplied the central feed port from the peripheral supply port, 3: 1 and it is not preferable to.
Thus, by setting the flow rate ratio of the gas supplied from the central supply port and the outer peripheral supply port to 3: 1, the area ratio between the central supply port and the outer peripheral supply port is 3: 1. The supply amount per unit area of the gas exiting from the supply port and the gas exiting from the outer periphery supply port can be made the same, and the laminar flow created by the central supply port and the outer periphery supply port becomes difficult to mix in the chamber.

Further, in the present invention, the gas discharge portion discharges gas along the inner wall of the chamber located at the outer periphery of at least a central discharge port for discharging the gas on the central portion side of the chamber. to it is rather preferred are those comprising an outer circumferential discharge opening, when the supplied gas is discharged by the gas discharge portion, of the central outlet and the central discharge port for discharging the central portion of the gas outer peripheral outlet located on the outer circumference to discharge the gas along the inner wall of the chamber and have preferably be discharged gas from.

  In this way, the gas discharge unit also corresponds to the gas supply unit, and the central discharge port for discharging the gas on the central side of the chamber, and the gas along the inner wall of the chamber located on the outer periphery of the central discharge port. By discharging the supplied gas with an outer peripheral discharge port, the mixing of the gas flowing in the center of the chamber and the gas along the inner wall can be reduced, and the surface roughness of the heated object can be reduced. It can be sufficiently prevented.

In the present invention, the gas discharge portion, Ki de be arranged to permit independent control of exhaust pressure of the gas discharged from the central discharge port and the outer circumferential discharge opening, further wherein the outer peripheral discharge and the central outlet the exhaust pressure of the gas discharged from the outlet, the gas of the central outlet of the outer peripheral outlet from the gas is not preferable to control so that the negative pressure.

  In this way, the gas discharge unit can individually control the discharge pressure of the gas discharged from the central discharge port and the outer discharge port, and control the gas at the outer discharge port to be a negative pressure from the gas at the central discharge port. Because the exhaust speed of the outer peripheral exhaust port is faster than the central exhaust port, it is possible to effectively suppress the gas along the inner wall of the chamber from losing momentum near the outer peripheral exhaust port and flowing into the central part. Furthermore, it is possible to prevent SiO from adhering to the object to be heated.

  With the single wafer type heat treatment apparatus and heat treatment method according to the present invention, even if the object to be heated is subjected to heat treatment of rapid heating / cooling at a high processing temperature of, for example, 1000 ° C. or higher, for preventing surface roughness. It is possible to safely suppress the occurrence of surface roughness on the surface of the object to be heated only by the gas flow without adding the above gas to the atmospheric gas. In addition, it is possible to use an inert gas as an atmosphere gas at 100% during the RTA treatment, there is little surface roughness, and there is little risk of metal contamination in the RTA treatment. can do.

As described above, an object to be heated such as a silicon wafer is placed in a heat treatment apparatus for performing a rapid heating / cooling process (RTA process) on the object to be heated, and the RTA process is performed in an inert gas atmosphere. Even if the purge time inside the chamber with nitrogen gas is set to a long time unit before the RTA treatment, or an atmospheric gas having a sufficiently reduced impurity concentration is used during the RTA treatment, a high temperature of, for example, 1000 ° C. or more is used. When the silicon wafer is annealed, the surface of the wafer is roughened. Therefore, when the wafer is measured by AFM, the roughness may be larger than that before the RTA treatment.
Since this uses an inert gas, it has been suggested that SiO is vaporized from the surface of the quartz chamber at a high temperature and adheres to and reacts with the wafer surface.

Therefore, the present inventors have conducted intensive research in order to solve such problems.
First, in the wafer manufacturing process, there are several processes for annealing a wafer at a high temperature with an inert gas, and various types of heat treatment furnaces are used. There are also a horizontal type furnace and a vertical type furnace that can process a plurality of objects to be heated together, and there is a single wafer type that processes wafers one by one. In these heat treatment apparatuses, there was no noticeable surface roughness on the wafer surface in the batch type apparatus.

  This is presumably because the distance between the quartz tube and the wafer in the batch heat treatment furnace is sufficiently large. That is, even if SiO is vaporized from the quartz tube, the distance is so great that the vaporized SiO does not immediately adhere to the wafer. Therefore, when the heat treatment was performed by placing the quartz tube close to the inner wall of the quartz tube, surface roughness occurred on the wafer surface.

  Therefore, it was thought that the single-wafer type heat treatment apparatus for RTA treatment could prevent surface roughness if the distance between the wafer and the quartz chamber was taken, but the single-wafer type heat treatment apparatus for treating wafers one by one Since the size of the chamber is reduced to improve thermal uniformity, if the chamber becomes larger, the advantages of the single wafer type are compromised and the thermal uniformity deteriorates within the wafer surface, so the distance between the wafer and the inner wall of the chamber. I couldn't take measures to take

  In addition, a method of adding hydrogen gas to the atmosphere gas as a method of solving the problem that surface roughness occurs on the surface of the wafer that is the object to be heated in the high-temperature annealing in an inert gas atmosphere using a single wafer type heat treatment apparatus However, when RTA treatment is performed by adding hydrogen gas, there are problems such as metal contamination and slip dislocation caused by the heat treatment. In addition, since hydrogen gas is handled, it is necessary to pay attention to the handling of atmospheric gas for safety.

  Therefore, it is advantageous to use 100% inert gas as the atmospheric gas, and various treatments are possible if RTA treatment without surface roughness is possible in high-temperature heat treatment with 100% inert gas. Further, if high-temperature RTA treatment in a 100% inert gas atmosphere is possible without causing surface roughness on the wafer surface, there is an advantage that the roughness of the wafer surface is reduced due to a sufficient migration effect. However, it was necessary to make the chamber small in order to achieve thermal uniformity.

  Therefore, in order to enable RTA treatment with less surface roughness even when an inert gas 100% is used as the atmospheric gas without increasing the chamber in order to maintain thermal uniformity, It is conceived that when the RTA treatment is performed on the object to be heated, it is only necessary to create a gas flow in the narrow chamber so that SiO vaporized from the quartz chamber does not adhere to the wafer as the object to be heated. Completed.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 4, but the present invention is not limited thereto.
FIG. 1 is a perspective view schematically showing a single wafer heat treatment apparatus according to the present invention. FIG. 2 is a schematic view of a gas supply unit viewed from the gas discharge unit side of the heat treatment apparatus shown in FIG. 3 is a longitudinal sectional view of the heat treatment apparatus shown in FIG. 4 is a plan view cross-sectional view of the heat treatment apparatus shown in FIG.

First, the single wafer type heat treatment apparatus of the present invention shown in FIG. 1 will be described.
This single-wafer type heat treatment apparatus 1 includes a quartz chamber 2 that accommodates an object to be heated W, a gas supply unit 3 that supplies gas into the chamber 2 from one end of the chamber 2, and a gas supply unit 3 A gas discharge unit 4 for discharging the supplied gas from the other end of the chamber 2 and a plurality of heating lamps 5 for heating the article to be heated W arranged outside the chamber 2 are provided in the chamber 2. The object to be heated W is heated while flowing the gas.

The chamber 2 is formed with a carry-in / out opening 7 for carrying in and out the article W to be heated, and has a shutter 8 for closing the carry-in / out entrance 7 to make the chamber 2 a closed space.
The chamber 2 has a susceptor 6 on which protrusions for placing the article to be heated W are formed.
A plurality of heating lamps 5 are installed at the top and bottom of the chamber so that power can be controlled individually. As the heating lamp 5, for example, a halogen lamp which is one of infrared lamps can be used.

  Further, in the single-wafer type heat treatment apparatus 1 of the present invention, the gas supply unit 3 is positioned on the outer periphery of the central supply port 3A for supplying gas to the central part side of the chamber 2 and the central supply port 3A. And an outer peripheral supply port 3B for supplying gas along the inner wall of the chamber 2.

  As described above, the gas supply unit 3 has a double pipe structure with the central supply port 3 </ b> A and the outer peripheral supply port 3 </ b> B, whereby a laminar flow of gas can be created in the chamber 2. That is, as shown in FIG. 2 and FIG. 3, the gas supply unit 3 extends along the gas GA supplied to the central portion side of the chamber 2 and the inner wall of the chamber 2 by the central supply port 3A and the outer peripheral supply port 3B. By supplying the gas GB, the gas can be layered in the chamber.

By providing the gas supply unit 3 with the central supply port 3A and the outer peripheral supply port 3B that can create such a laminar flow of gas, the gas supplied from the outer peripheral supply port and along the inner wall of the chamber is subjected to a high temperature RTA process. Since SiO vaporized from the inner wall of the chamber can be prevented from flowing into the center of the chamber, even if SiO is vaporized from the quartz chamber surface during the RTA treatment, the vaporized SiO is less likely to adhere to the object to be heated.
Therefore, during the RTA treatment, even when the heat treatment is performed at a high temperature of 1000 ° C. or more, it is possible to easily suppress the SiO vaporized from the chamber surface from adhering to the object to be heated only by the gas flow.

This also prevents the surface of the heated object from being roughened during the RTA process, and the heated object can maintain a desired roughness even when the RTA process is performed.
Furthermore, surface roughness of the heated object surface can be suppressed only by the gas flow created by the central supply port and the outer peripheral supply port, so it is safe to handle hydrogen gas used as a countermeasure against surface roughness of the heated object. In addition, the gas to be used can be 100% inert gas, and metal contamination and slip dislocation of the heated object due to the addition of hydrogen gas do not occur.

In this case, it is preferable that the gas supply unit 3 can individually control the flow rate of the gas supplied from the central supply port 3A and the outer peripheral supply port 3B.
In this way, if the flow rate of the gas supplied from the central supply port and the outer peripheral supply port can be individually controlled, the SiO vaporized from the inner wall of the chamber in accordance with the area of each gas supply port can be treated. A gas flow that does not adhere to the heated object can be easily created.

The area ratio between the central supply port 3A and the outer peripheral supply port 3B included in the gas supply unit 3 is preferably 3: 1.
Thus, (area of the central supply port 3A) :( area of the outer peripheral supply port 3B) = 3: 1 allows the gas supplied from the outer peripheral supply port along the inner wall of the chamber 2 to be supplied from the central supply port. A gas layer having a sufficient thickness such that the supplied gas does not hit the inner wall of the chamber can be created.

Further, in the present invention, the gas discharge unit 4 discharges the gas along the inner wall of the chamber 2 located at the outer periphery of the central discharge port 4A and the central discharge port 4A for discharging the gas on the central side of the chamber 2. It is preferable that the outer peripheral discharge port 4B is provided.
As described above, the gas discharge unit 4 is also arranged to face the gas supply unit 3, and the central discharge port 4 </ b> A for discharging the gas on the central side and the outer peripheral discharge port 4 </ b> B for discharging the gas along the inner wall of the chamber 2. The mixing of the gas flowing in the center of the chamber and the gas along the inner wall can be reduced, and the surface roughness of the object to be heated can be sufficiently prevented.

And it is preferable that the said gas discharge part 4 shall be able to control separately the discharge pressure of the gas discharged | emitted from 4A of center discharge ports, and the outer periphery discharge port 4B.
In this way, if the discharge pressure of the gas discharged from the central discharge port 4A and the outer discharge port 4B can be individually controlled, SiO is attached to the object to be heated by adjusting the discharge pressures at the outer periphery and the center. This can be prevented more effectively.

  In FIG. 1, the central supply port 3 </ b> A and the outer peripheral supply port 3 </ b> B for supplying gas, and the central discharge port 4 </ b> A and the outer peripheral discharge port 4 </ b> B for discharging gas are rectangular in shape. There may be. In this invention, in order to form the outer periphery supply port (outer periphery discharge port) surrounding the outer side of a center supply port (center discharge port), a center supply port (center discharge port) is provided in the chamber 2, The region sandwiched between the central supply port (central discharge port) is configured as an outer peripheral supply port (outer peripheral discharge port).

However, the present invention is not limited to this, and the outer peripheral supply port (outer peripheral discharge port) may be, for example, a tube having a circular port arranged so as to surround a plurality of central supply ports (central discharge port). Good.
The central supply port (central discharge port) may be, for example, a collection of a plurality of tubes having a circular port, and the supply (discharge) amount and pressure of a rectangular port as shown in FIG. May be provided with slits for the purpose of equalizing in the wafer surface.
Furthermore, in the above description, the case where the central supply port (central discharge port) and the outer peripheral supply port (outer discharge port) are double pipes has been described as an example, but a triple pipe or more may be used. .

Next, the heat treatment method of the present invention for heat-treating the article to be heated W using the single wafer heat treatment apparatus 1 shown in FIG. 1 described above will be described.
The heat treatment method described below is for a case where a silicon wafer as an object to be heated W is subjected to a high temperature of 1000 ° C. or more and rapid heating / cooling (RTA) treatment, but the present invention is naturally limited to this. Not.

First, a single wafer heat treatment apparatus 1 as shown in FIG. 1 is prepared.
Next, the shutter 8 of the quartz chamber 2 is opened, the silicon wafer W as the object to be heated is loaded from the loading / unloading port 7, placed on the susceptor 6 in the chamber 2, the shutter 8 is closed, A silicon wafer W is accommodated in the chamber 2.
The loading method is not particularly limited, but a wafer handling device (not shown) or the like may be used.

Then, after purging the atmosphere in the chamber 2 by flowing a gas such as nitrogen, the gas is supplied into the chamber 2 from the gas supply unit 3 located at one end of the chamber 2.
At this time, gas is supplied from a central supply port 3A for supplying gas to the central portion side of the chamber 2 and an outer peripheral supply port 3B for supplying gas along the inner wall of the chamber 2 located on the outer periphery of the central supply port 3A. To do. As the gas to be supplied, the central supply port 3A and the outer peripheral supply port 3B are the same argon gas 100%.

  In this way, by supplying the gas from the double pipe structure constituted by the central supply port 3A and the outer peripheral supply port 3B, there is a possibility of directly hitting the silicon wafer as shown in FIGS. The gas GA flowing in the center of the chamber and the gas GB along the inner wall of the chamber are layered, and the gas GA near the center can be prevented from colliding with the inner wall of the chamber due to the layer of gas GB along the inner wall. Therefore, even if SiO is vaporized from the quartz chamber surface during the RTA process, the gas flow is such that the vaporized SiO does not adhere to the object to be heated, so that the surface of the object to be heated during the RTA process becomes rough. The object to be heated can maintain the desired roughness even when the RTA treatment is performed.

  In addition, since the surface roughness of the object to be heated can be suppressed only by the gas flow, it is advantageous in terms of safety without handling the hydrogen gas that is used as a countermeasure against the surface roughness of the object to be heated. Can be reduced to 100% inert gas, and the addition of hydrogen gas reduces the risk of metal contamination of the silicon wafer and the occurrence of slip dislocations.

Further, it is preferable to individually control the flow rate of the gas supplied from the central supply port 3A and the outer peripheral supply port 3B. In particular, in the present invention, the flow rate ratio of the gas supplied from the central supply port 3A and the outer peripheral supply port 3B is 3 : 1 is preferable.
In this way, by individually controlling the flow rate of the gas supplied from the central supply port and the outer peripheral supply port, the ratio is set to 3: 1, so that the vaporized SiO 2 in accordance with the size of each gas supply port. Can easily create a gas flow that does not adhere to the object to be heated, and when the area ratio between the central supply port and the outer peripheral supply port is 3: 1, The gas supply amount per unit area of the gas exiting from the outer peripheral supply port can be made the same. Therefore, the laminar flow created by the central supply port and the outer peripheral supply port is difficult to mix in the chamber, and surface roughness of the wafer surface due to SiO can be prevented.

Next, the gas supplied by the gas discharge part 4 located at the other end of the chamber 2 is discharged, and thereby the gas flows into the chamber.
When the supplied gas is discharged by the gas discharge unit 4, the central discharge port 4 </ b> A for discharging the gas on the central side and the gas along the inner wall of the chamber 2 located at the outer periphery of the central discharge port 4 </ b> A are discharged. The gas is discharged from the outer peripheral discharge port 4B.

  In this way, the gas discharge unit corresponding to the gas supply unit discharges the gas along the inner wall of the chamber located at the outer periphery of the central discharge port and the central discharge port for discharging the gas on the central side of the chamber. By discharging from the outer peripheral discharge port, the mixing of the gas flowing in the center of the chamber and the gas along the inner wall can be reduced, and the surface roughness of the heated object can be sufficiently prevented.

And it is preferable to control the discharge pressure of the gas discharged from the central outlet 4A and the outer peripheral outlet 4B so that the gas at the outer peripheral outlet 4B becomes a negative pressure from the gas at the central outlet 4A.
By controlling the discharge pressure of the gas discharged from the central discharge port 4A and the outer discharge port 4B individually so that the gas at the outer discharge port becomes negative pressure than the gas at the central discharge port, Since the exhaust speed of the outer peripheral exhaust port is faster than that of the outlet, it is possible to effectively suppress the gas along the inner wall of the chamber from losing momentum near the outer peripheral exhaust port and flowing into the central portion. It can prevent adhering to an object to be heated.

  Next, the object to be heated W is heated up to a target temperature by the heating lamp 5 disposed outside the chamber 2. Then, after a high temperature heat treatment is applied for a predetermined time at the desired temperature, the output of the heating lamp 5 is lowered to lower the temperature of the article to be heated W, and the RTA treatment is completed.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.
Example 1
<Specifications of heat treatment equipment>
The single wafer heat treatment apparatus used in Example 1 includes a quartz chamber, a gas supply unit, a gas discharge unit, and a plurality of halogen lamps. The chamber is formed with a wafer carry-in / out opening, and a shutter for closing it is attached. Further, a susceptor for placing a silicon wafer, which is an object to be heated, is installed in the chamber.
The gas discharge unit includes one discharge port, and the gas supply unit includes a central supply port that supplies gas to the central portion side of the chamber and an outer peripheral supply port that supplies gas along the inner wall of the chamber. It has. The shape and arrangement of the central supply port and the outer peripheral supply port are the same as those shown in FIG.
The area ratio between the central supply port and the outer peripheral supply port was 3: 1.

<Heat treatment>
Using the single wafer heat treatment apparatus, a silicon wafer having a diameter of 300 mm was subjected to rapid heating / cooling treatment. At this time, argon gas 100% was used as the atmospheric gas, and was flowed at 3: 1 from the central supply port and the outer peripheral supply port so that the flow rate ratio was the same as the area ratio of the port. Then, the silicon wafer was heated to 1100 ° C. and held for 30 seconds, and immediately after that, the output of the halogen lamp was lowered to cool the silicon wafer.

<Roughness measurement of wafer surface>
As described above, when the silicon wafer subjected to the high temperature RTA treatment was taken out of the chamber and the wafer surface was visually observed, there was no change compared to the wafer before the RTA treatment. Further, as a result of measuring the roughness of the wafer surface (measurement region 10 μm × 10 μm Rmax) by AFM, the roughness of the wafer surface before the RTA process is 1.1 nm, whereas the roughness of the wafer surface after the RTA process is 0. .9 nm.
As a result, even if high temperature RTA processing is performed on a silicon wafer using 100% inert gas without adding surface roughening prevention gas, processing with less surface roughness can be performed and effective migration can be obtained. I understand that

(Example 2)
<Specifications of heat treatment equipment>
The single wafer type heat treatment apparatus used in Example 2 has the same configuration as the heat treatment apparatus used in Example 1 except for the gas discharge unit.
The gas discharge portion is not a single discharge port as in the first embodiment, but a central discharge port for discharging the gas on the central portion side of the chamber, and an outer periphery of the central discharge port and along the inner wall of the chamber. And an outer peripheral discharge port for discharging the gas.
The shape and arrangement of the central outlet and the outer peripheral outlet are the same as those shown in FIG.
The area ratio between the central outlet and the outer peripheral outlet was 3: 1 so as to correspond to the gas supply unit.

<Heat treatment>
Using the single wafer heat treatment apparatus, a silicon wafer having a diameter of 300 mm was subjected to rapid heating / cooling treatment. At this time, argon gas 100% was used as the atmospheric gas, and was flowed at 3: 1 from the central supply port and the outer peripheral supply port so that the flow rate ratio was the same as the area ratio of the port.
Further, the discharge pressure of the gas discharged from the central discharge port and the outer peripheral discharge port was controlled so that the pressure of the gas discharged from the outer peripheral discharge port became more negative than the pressure of the gas discharged from the central discharge port.
Then, the silicon wafer was heated to 1100 ° C. and held for 30 seconds, and immediately after that, the output of the halogen lamp was lowered to cool the silicon wafer.

<Roughness measurement of wafer surface>
As described above, when the silicon wafer subjected to the high temperature RTA treatment was taken out of the chamber and the wafer surface was visually observed, there was no change compared to the wafer before the RTA treatment. Further, as a result of measuring the roughness of the wafer surface by AFM, the roughness of the wafer surface before the RTA process was 1.1 nm, whereas the roughness of the wafer surface after the RTA process was 0.8 nm.
Comparing the results of Example 2 with the results of Example 1, it can be seen that the change in roughness of the wafer surface is further suppressed.
Thus, even if a high temperature RTA treatment is performed on a silicon wafer using an inert gas 100% without adding a surface roughening prevention gas, the gas discharge portion is further made into a double tube structure, It can be seen that processing with less surface roughness can be performed, and more effective migration can be obtained.

(Comparative example)
<Specifications of heat treatment equipment>
The single wafer heat treatment apparatus used in the comparative example includes a quartz chamber, a gas supply unit, a gas discharge unit, and a plurality of halogen lamps. The chamber is formed with a wafer carry-in / out opening, and a shutter for closing it is attached. Further, a susceptor for placing a silicon wafer, which is an object to be heated, is installed in the chamber.
The gas supply unit and the gas discharge unit each have one supply port and one discharge port.

<Heat treatment>
Using the single wafer heat treatment apparatus, a silicon wafer having a diameter of 300 mm was subjected to rapid heating / cooling treatment. At this time, 100% argon gas was flowed as the atmospheric gas. Then, the silicon wafer was heated to 1100 ° C. and held for 30 seconds, and immediately after that, the output of the halogen lamp was lowered to cool the silicon wafer.

<Roughness measurement of wafer surface>
When a silicon wafer subjected to such a high-temperature RTA process was taken out of the chamber and the wafer surface was visually observed, surface roughness occurred compared to the wafer before the RTA process. Further, as a result of measuring the roughness of the wafer surface by AFM, the roughness of the wafer surface before the RTA process was 1.1 nm, whereas the roughness of the wafer surface after the RTA process was 2.4 nm. From this result, it can be seen that the wafer surface roughness after the high-temperature RTA treatment is considerably larger than that before the RTA treatment when the gas supply unit does not have a double tube structure.

  From the above results, Example 1 in which the gas supply unit has a double-pipe structure, Example 2 in which both the gas supply unit and the gas discharge unit have a double-pipe structure, and the supply port and the discharge port have a double-pipe structure. Comparing the results of the comparative examples that are not, it can be seen that the RTA treatment with less surface roughness can be performed in the embodiment, and more effective migration can be obtained.

  Therefore, with the single wafer type heat treatment apparatus and heat treatment method according to the present invention, even if the silicon wafer is subjected to rapid heating / cooling heat treatment at a high temperature of, for example, 1000 ° C. or more, the surface roughening gas is an atmospheric gas. It is possible to suppress the occurrence of surface roughness only by the flow of gas without adding to. In addition, an inert gas can be used as an atmosphere gas at 100% during the RTA process, and a silicon wafer with less surface roughness and less risk of metal contamination in the RTA process can be obtained.

  The present invention is not limited to the above embodiment. The above embodiment is merely an example, and the present invention has the same configuration as that of the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

It is a perspective view which shows the outline of the single-wafer | sheet-fed heat processing apparatus which concerns on this invention. It is the schematic of the gas supply part seen from the gas discharge part side of the heat processing apparatus shown in FIG. It is a longitudinal cross-sectional view of the heat processing apparatus shown in FIG. FIG. 2 is a plan view sectional view of the heat treatment apparatus shown in FIG. 1. It is the schematic of the conventional single wafer type heat processing apparatus.

Explanation of symbols

1, 51 ... single-wafer heat treatment apparatus, 2, 52 ... chamber,
3, 53 ... Gas supply part, 3A ... Central supply port, 3B ... Outer periphery supply port,
4, 54 ... gas discharge part, 4A ... center discharge port, 4B ... outer periphery discharge port,
5, 55 ... heating lamp, 6, 56 ... susceptor, 7, 57 ... loading / unloading port,
8, 58 ... Shutter, G ... Atmospheric gas,
GA: Gas passing through the center of the chamber, GB: Gas along the inner wall of the chamber,
W: Object to be heated (silicon wafer).

Claims (10)

At least a quartz chamber for containing an object to be heated;
A gas supply unit for supplying gas into the chamber from one end of the chamber;
A gas discharge unit for discharging the gas supplied from the gas supply unit from the other end of the chamber;
A heating lamp for heating the object to be heated disposed outside the chamber;
In a single wafer type heat treatment apparatus that heats the object to be heated while flowing gas in the chamber,
The gas supply unit is at least
A central supply port for supplying gas to the central portion side of the chamber;
An outer peripheral supply port which surrounds the outside of the central supply port and supplies gas along the inner wall of the chamber;
A single-wafer type heat treatment apparatus that heats the object to be heated while supplying gas from the central supply port and the outer peripheral supply port.   The single-wafer type heat treatment apparatus according to claim 1, wherein the gas supply unit is capable of individually controlling a flow rate of gas supplied from the central supply port and the outer peripheral supply port.   The single-wafer type heat treatment apparatus according to claim 1 or 2, wherein an area ratio between the central supply port and the outer peripheral supply port is 3: 1. The gas discharge part is at least
A central outlet for discharging the gas on the central side of the chamber;
4. The outer peripheral discharge port that is located on the outer periphery of the central discharge port and discharges gas along the inner wall of the chamber is provided. 5. Single wafer type heat treatment equipment.   The single-wafer heat treatment apparatus according to claim 4, wherein the gas discharge unit is capable of individually controlling a discharge pressure of gas discharged from the central discharge port and the outer peripheral discharge port. At least the object to be heated is contained in a quartz chamber,
Gas is supplied into the chamber from a gas supply unit located at one end of the chamber, and the gas is flowed into the chamber by discharging the supplied gas through a gas discharge unit located at the other end of the chamber,
In the heat treatment method of performing a heat treatment on the object to be heated by a heating lamp disposed outside the chamber,
When supplying gas into the chamber from the gas supply unit, a gas is supplied along the inner wall of the chamber surrounding the outside of the central supply port and the central supply port for supplying gas to the central portion side of the chamber A heat treatment method, wherein the object to be heated is subjected to heat treatment while supplying gas from an outer peripheral supply port.   The heat treatment method according to claim 6, wherein the flow rate of the gas supplied from the central supply port and the outer peripheral supply port is individually controlled.   The heat treatment method according to claim 6 or 7, wherein a flow ratio of gas supplied from the central supply port and the outer peripheral supply port is set to 3: 1.   When the supplied gas is discharged by the gas discharge portion, a central discharge port for discharging the gas on the central portion side and an outer periphery that is located on the outer periphery of the central discharge port and discharges the gas along the inner wall of the chamber The heat treatment method according to any one of claims 6 to 8, wherein gas is discharged from the discharge port.   The discharge pressure of the gas discharged from the central discharge port and the outer peripheral discharge port is controlled so that the gas at the outer peripheral discharge port becomes a negative pressure from the gas at the central discharge port. Heat treatment method.

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