JP4700300B2 - Heat treatment equipment - Google Patents

Description

  The present invention relates to a heat treatment apparatus for heat treating a semiconductor wafer, a glass substrate or the like.

A heat treatment apparatus having a vertical furnace in which a plurality of substrates are mounted on a boat and heat-treated by high-temperature heating at a temperature of, for example, about 1200 ° C. is known.
In this type of heat treatment apparatus, it is known to perform heat treatment by shielding the furnace port below the reaction furnace with a furnace port cap having a heat insulating member (see Patent Document 1).

JP-A-6-338473

However, when the substrate is heat-treated at a higher temperature, for example, 1350 ° C., if the heat insulating member provided below the support for supporting the substrate is made of quartz (SiO ₂ ), the quartz is deformed due to a creep phenomenon. There is a fear. When the quartz heat insulating member is deformed, the heat insulating effect of the heat insulating member is lowered, and the furnace port cap becomes high temperature. When the furnace port cap reaches a high temperature, the O-ring which is a seal material for the furnace port part and has a heat-resistant temperature of, for example, 250 ° C. melts, and the shielding by the furnace port cap is lost. Furthermore, if the O-ring melts and the shielding property of the furnace port portion is lost, the support tool may fall down and be damaged, or the substrate supported by the support tool may be damaged.

  An object of the present invention is to provide a heat treatment apparatus having a heat insulation structure capable of effectively performing heat insulation even when heat treatment is performed at a high temperature, for example, a temperature of 1350 ° C. or higher.

  In order to solve the above-mentioned problems, the first feature of the present invention is that a reaction chamber having a furnace port provided at the lower end, a support member for supporting a substrate in the reaction chamber, and a lower part below the support member. A plurality of heat insulation plates made of silicon carbide provided in the vertical direction with a pitch of 1, a plurality of heat insulation plates made of quartz provided in the vertical direction with a second pitch below the heat insulation plates made of silicon carbide; A furnace port cap provided below the plurality of quartz heat insulating plates and closing the furnace port of the reaction chamber, and the first pitch of the silicon carbide heat insulating plates is a second pitch of the quartz heat insulating plate. There is a heat treatment apparatus that is larger than the pitch. Where the first pitch of the silicon carbide heat insulating plate is the same as the second pitch of the quartz heat insulating plate, the first pitch of the silicon carbide heat insulating plate is set to be greater than the second pitch of the quartz heat insulating plate. However, it has been confirmed by experiments that the effect of insulating heat at a high temperature of 1350 ° C. or higher is equivalent. Further, when the substrate is heat-treated in the atmosphere of the processing gas, a heat insulating layer made of the processing gas (gas) is formed on the first pitch of the silicon carbide (SiC) heat insulating plate larger than the second pitch of the quartz heat insulating plate. When it is done, the heat insulation effect improves. Thus, by making the 1st pitch of a silicon carbide heat insulation board larger than the 2nd pitch of a quartz heat insulation board, weight reduction and cost reduction of a plurality of silicon carbide heat insulation boards are acquired, obtaining a heat insulation effect. In addition, the heat capacity in the reaction chamber can be reduced.

  The second feature of the present invention is that a reaction chamber having a furnace port at the lower end, a support for supporting the substrate in the reaction chamber, and a vertical direction below the support are provided. A plurality of heat insulation plates made of silicon carbide, a plurality of heat insulation plates made of quartz provided in the vertical direction below the heat insulation plates made of silicon carbide, and the reaction chamber provided below the heat insulation plates made of quartz made of quartz. A furnace port cap for closing the furnace port, and the thickness of the silicon carbide heat insulating plate is smaller than the thickness of the quartz heat insulating plate. Even if the silicon carbide heat insulating plate is thinner than the quartz heat insulating plate, it has a heat insulating effect against heat of 1350 ° C. or higher. In addition, the plurality of quartz heat insulating plates have a larger heat capacity than the silicon carbide member and insulate the low-temperature heat after being insulated by the plurality of silicon carbide heat insulating plates. In addition, the heat transmitted through the silicon carbide heat insulating plate can be blocked. In this way, by making the thickness of the silicon carbide heat insulating plate thinner than that of the quartz heat insulating plate, the heat insulating effect can be obtained while reducing the weight of the plurality of silicon carbide heat insulating plates and reducing the heat capacity in the reaction chamber. You can plan.

  According to the present invention, even when heat treatment is performed at a high temperature, for example, a temperature of 1350 ° C. or higher, heat insulation can be performed effectively.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a heat treatment apparatus 10 according to an embodiment of the present invention. The heat treatment apparatus 10 is, for example, a vertical type and includes a casing 12 in which a main part is arranged. A pod stage 14 is connected to the housing 12, and the pod 16 is conveyed to the pod stage 14. The pod 16 stores, for example, 25 substrates, and is set on the pod stage 14 with a lid (not shown) closed.

  In the housing 12, a pod transfer device 18 is disposed at a position facing the pod stage 14. Further, a pod shelf 20, a pod opener 22, and a substrate number detector 24 are arranged in the vicinity of the pod transfer device 18. The pod carrying device 18 carries the pod 16 among the pod stage 14, the pod shelf 20, and the pod opener 22. The pod opener 22 opens the lid of the pod 16, and the number of substrates in the pod 16 with the lid opened is detected by the substrate number detector 24.

  Further, a substrate transfer machine 26, a notch aligner 28, and a support tool 30 (boat) are disposed in the housing 12. The substrate transfer machine 26 includes an arm 32 that can take out, for example, five substrates. By moving this arm 32, the pod 16 placed at the position of the pod opener 22, the notch aligner 28, and the support 30. Transfer the substrate between. The notch aligner 28 detects notches or orientation flats formed on the substrate and aligns the notches or orientation flats of the substrate at a certain position.

  In FIG. 2, a reactor 40 is shown. This reaction furnace 40 has a reaction tube 42 made of SiC. The reaction tube 42 is formed in a cylindrical shape with the upper part sealed, the lower part is formed in a flange shape, and the inside is a reaction chamber 43. A quartz adapter 44 is disposed below the reaction tube 42, and the reaction tube 42 is supported by the adapter 44. A heater 46 is disposed around the reaction tube 42 excluding the adapter 44.

  The aforementioned support 30 is inserted into the reaction tube 42. The lower part of the reaction tube 42 is opened to insert the support tool 30, and this open part is sealed by the furnace port cap 48 coming into contact with the adapter 44. Between the furnace cap 48 and the support 30, a first heat insulating portion 50 made of SiC provided below the support 30 and a quartz made of quartz provided below the first heat insulating portion 50. The second heat insulating part 52 is interposed. The support 30 supports a large number of substrates 54 in a substantially horizontal state with a plurality of steps with gaps, and is loaded into the reaction tube 42.

  The adapter 44 is formed with a gas supply port 56 and a gas exhaust port 58 integrally with the adapter 44. A gas introduction pipe 60 is connected to the gas supply port 56, and an exhaust pipe 62 is connected to the gas exhaust port 58. A gas introduction path extending in the vertical direction is provided inside the adapter 44, and a nozzle mounting hole 64 is formed in the upper portion so as to open upward. The nozzle mounting hole 64 is connected to the gas supply port 56 via a gas introduction path. A nozzle 66 is inserted and fixed in the nozzle mounting hole 64. That is, the nozzle 66 is connected to the upper surface of the adapter 44.

  With this configuration, the nozzle connection portion is not easily deformed by heat and is not easily damaged. Further, there is an advantage that the assembly and disassembly of the nozzle 66 and the adapter 44 are facilitated. The processing gas introduced from the gas introduction pipe 60 to the gas supply port 56 is supplied into the reaction pipe 42 through the nozzle 66. The nozzle 66 is configured to extend along the inner wall of the reaction tube 42 to above the substrate arrangement region (above the support tool 30). The nozzle 66 has an inner diameter of 10 mm and a length of 1000 mm, for example.

  In the reaction furnace 40, the reaction tube 42 is made of SiC as described above in order to enable processing at a high temperature of 1200 ° C. or higher. For example, the annealing temperature for manufacturing a SIMOX (Separation by Implanted Oxygen) wafer described later is 1350 ° C. or higher. On the other hand, if the first heat insulating portion 50 located below the support 30 on which the substrate is supported is made of quartz, when the processing temperature is 1350 ° C. or higher, the quartz may cause a creep phenomenon and deform. There is.

  When the first heat insulating portion 50 made of quartz is deformed, the heat insulating effect by the first heat insulating portion 50 is lowered, and the furnace port cap 48 becomes high temperature. When the furnace port cap 48 reaches a high temperature, the O-ring, which is a seal material for the furnace port part and has a heat-resistant temperature of, for example, 250 ° C. melts, and the shielding by the furnace port cap 48 is lost. Furthermore, if the O-ring melts and the shielding property of the furnace port portion is lost, the support tool 30 may fall down and be damaged, or the substrate supported by the support tool 30 may be damaged. Therefore, by making the first heat insulating portion 50 made of SiC, the first heat insulating portion 50 maintains heat insulating properties even when the processing temperature in the reaction tube 42 is 1350 ° C. or higher.

Next, the operation of the heat treatment apparatus 10 configured as described above will be described.
First, when a pod 16 containing a plurality of substrates is set on the pod stage 14, the pod 16 is transferred from the pod stage 14 to the pod shelf 20 by the pod transfer device 18 and stocked on the pod shelf 20. Next, the pod 16 stocked on the pod shelf 20 is transported and set to the pod opener 22 by the pod transport device 18, the lid of the pod 16 is opened by the pod opener 22, and the pod 16 is detected by the substrate number detector 24. The number of substrates accommodated in the sensor is detected.

  Next, the substrate is transferred from the pod 16 at the position of the pod opener 22 by the substrate transfer machine 26 and transferred to the notch aligner 28. The notch aligner 28 detects notches while rotating the substrates, and aligns the notches of the plurality of substrates at the same position based on the detected information. Next, the substrate is transferred from the notch aligner 28 by the substrate transfer machine 26 and transferred to the support 30.

  In this way, when one batch of substrates is transferred to the support tool 30, for example, the support tool 30 loaded with a plurality of substrates is loaded into the reaction furnace 40 set to a temperature of about 700 ° C. The inside of the reaction tube 42 is sealed with the furnace port cap 48. Next, the furnace temperature is raised to the heat treatment temperature, and the processing gas is introduced into the reaction tube 42 from the gas introduction tube 60 through the gas introduction port 56 and the nozzle 66. The processing gas includes nitrogen, argon, hydrogen, oxygen, and the like. When heat-treating the substrate, the substrate is heated to a temperature of about 1350 ° C. or more, for example. The 1st heat insulation part 50 and the 2nd heat insulation part 52 insulate the heat in the reaction tube 42 in heat processing, and keep the temperature of the furnace port cap 48 from rising.

  When the heat treatment of the substrate is completed, for example, after the temperature in the furnace is lowered to a temperature of about 700 ° C., the support 30 is unloaded from the reaction furnace 40 and is supported until all the substrates supported by the support 30 are cooled. The tool 30 is put on standby at a predetermined position. Next, when the substrate of the support 30 that has been waiting is cooled to a predetermined temperature, the substrate transfer machine 26 takes out the substrate from the support 30 and transports it to the empty pod 16 set in the pod opener 22. And accommodate. Next, the pod carrying device 18 carries the pod 16 containing the substrate to the pod shelf 20 and further to the pod stage 14 to complete.

Next, the 1st heat insulation part 50 and the 2nd heat insulation part 52 are explained in full detail.
In FIG. 3, the 1st example of the 1st heat insulation part 50 and the 2nd heat insulation part 52 which insulate in the reaction tube 42 is shown.
In the first example, the first heat insulating portion 50 is composed of a plurality of SiC heat insulating plates 68 and is supported in parallel to the substrate 54 supported by the support tool 30, for example. The SiC heat insulating plate 68 is, for example, a Si-impregnated disk-shaped SiC member having a thickness of about 3 mm, and insulates by radiating light from the heater 46. Further, since the SiC heat insulating plate 68 has a smaller heat capacity than the quartz member and is formed in a plate shape, it is possible to reduce a delay in response in temperature control in the reaction tube 42.
The second heat insulating portion 52 includes a quartz heat insulating plate 70 which is a plurality of disk-shaped members having a thickness of about 3 mm, for example, and is supported in parallel to the SiC heat insulating plate 68, for example.

  The pitch between the SiC heat insulating plates 68 and 68 is larger than the pitch between the quartz heat insulating plates 70 and 70. Since SiC hardly transmits radiation and has excellent heat insulation properties, as shown in FIG. 3 (a), even if the pitch between the SiC heat insulating plates 68, 68 is increased to some extent, a plurality of SiC heat insulating materials are used. This is because the radiation can be interrupted intermittently by the plate 68. In FIG. 3A, the pitch between the SiC heat insulating plates 68 and 68 is set to be four times or more the pitch between the quartz heat insulating plates 70 and 70.

  Also, as shown in FIG. 3B, for example, when heat treatment is performed at 1350 ° C. or higher in the reaction tube 42, SiC heat insulation is prevented so that convection of the processing gas does not occur between the SiC heat insulation plates 68, 68. By setting the pitch between the plates 68, 68, a heat insulating layer made of a processing gas (gas) is formed between the SiC heat insulating plates 68, 68. The heat insulating layer made of the processing gas can block the heat generated by the radiation from the heater 46 together with the SiC heat insulating plate 68. In FIG. 3B, the pitch between the SiC heat insulating plates 68 and 68 is set to be twice or more the pitch between the quartz heat insulating plates 70 and 70.

  In the second heat insulating portion 52, the temperature is lower than the surroundings of the substrate 54 due to the heat insulating effect of the first heat insulating portion 50, so the heater that has passed through the first heat insulating portion 50 by the quartz heat insulating plate 70. The radiation light from 46 can be blocked. Further, the heat insulating plate 70 made of quartz has a heat capacity larger than that of a member made of SiC, and receives heat in the reaction tube 42 so that the temperature of the furnace port cap 48 does not rise.

  In addition, in the 1st heat insulation part 50 and the 2nd heat insulation part 52, compared with the case where the pitch between the SiC heat insulation boards 68 and 68 and the pitch between the quartz heat insulation boards 70 and 70 are the same pitch, it is made of SiC. Even if the number of the heat insulating plates 68 is reduced so that the pitch between the SiC heat insulating plates 68 and 68 is larger than the pitch between the quartz heat insulating plates 70 and 70, the first heat insulating portion 50 and the second heat insulating portion 52 Experiments have confirmed that the heat insulation effect is equivalent.

  Therefore, by reducing the number of the SiC heat insulating plates 68 and making the pitch between the SiC heat insulating plates 68 and 68 larger than the pitch between the quartz heat insulating plates 70 and 70, the first heat insulating portion is obtained while obtaining a heat insulating effect. 50 can be reduced in weight and cost, and the heat capacity in the reaction tube 42 can be reduced.

In FIG. 4, the 2nd example of the 1st heat insulation part 50 and the 2nd heat insulation part 52 which heat-insulate in the reaction tube 42 is shown.
In the second example, the first heat insulating portion 50 is composed of a plurality of SiC heat insulating plates 72 and is supported in parallel to the substrate 54 supported by the support tool 30, for example.
In the second example, parts that are substantially the same as those in the first example shown in FIG.

  The SiC heat insulating plate 72 is a high purity SiC disk-shaped member having a thickness of 1 mm or less formed by, for example, CVD (Chemical Vapor Deposition), and, similar to the Si-impregnated SiC heat insulating plate 68, the heater Insulate by blocking the radiation from 46. Further, the thickness of the SiC heat insulating plate 72 is thinner than the thickness of the quartz heat insulating plate 70, and is thinner than the Si-impregnated SiC heat insulating plate 68 in the first example.

As described above, in the first heat insulating portion 50 and the second heat insulating portion 52, the thickness of the SiC heat insulating plate 72 is smaller than the thickness of the quartz heat insulating plate 70, and the Si impregnated SiC heat insulating plate 68. Even if it is made thinner, it has been confirmed by experiments that the heat insulating effects by the first heat insulating part 50 and the second heat insulating part 52 are equivalent.
Therefore, in the second example of the first heat insulating part 50 and the second heat insulating part 52, while maintaining the heat insulating effect, the first heat insulating part 50 is lighter than the first example and the heat capacity in the reaction tube 42 is lower. Can be achieved.

In FIG. 5, details of a third example of the first heat insulating portion 50 and the second heat insulating portion 52 that are thermally insulated in the reaction tube 42 are shown.
In the third example, the first heat insulating portion 50 is composed of a plurality of SiC heat insulating plates 72 and is supported in parallel to the substrate 54 supported by the support tool 30, for example. Similar to the second example, the SiC heat insulating plate 72 is a high purity SiC disk-shaped member having a thickness of 1 mm or less formed by CVD, for example, and is thinner than the thickness of the quartz heat insulating plate 70. The second heat insulating portion 52 is composed of a plurality of quartz heat insulating plates 70 as in the first and second examples. For example, the second heat insulating portion 52 is equal to or more than the number of SiC heat insulating plates 72 supported in parallel to the SiC heat insulating plate 72. The quartz heat insulating plate 70 is used.
Note that, in the third example, the same reference numerals are given to the same portions as those in the first example shown in FIG. 3 and the second example shown in FIG.

  As described above, the SiC heat insulating plate 72 is a disk member of high purity SiC having a thickness a of 1 mm or less, and is thinner than the quartz heat insulating plate 70 having a thickness c. Further, the pitch b between the heat insulating plates 72 and 72 made of SiC is larger than the pitch d between the heat insulating plates 70 and 70 made of quartz, and when the heat treatment is performed at 1350 ° C. or higher in the reaction tube 42, It is set so that convection of the processing gas does not occur between the SiC heat insulating plates 72, 72. Accordingly, when heat treatment is performed at 1350 ° C. or higher in the reaction tube 42, a heat insulating layer is formed between the heat insulating plates 72 and 72 made of SiC. The heat insulating layer made of the processing gas can block the heat generated by the radiation from the heater 46 together with the SiC heat insulating plate 72.

Thus, in the 1st heat insulation part 50 and the 2nd heat insulation part 52, the thickness of the heat insulation board 72 made from SiC is made thinner than the thickness of the heat insulation board 70 made from quartz, and also between the heat insulation boards 72, 72 made from SiC. It has been experimentally confirmed that even if the pitch is larger than the pitch between the quartz heat insulating plates 70, 70, the heat insulating effect by the first heat insulating portion 50 and the second heat insulating portion 52 is equivalent.
Therefore, the third example can reduce the weight of the first heat insulating portion 50 and lower the heat capacity in the reaction tube 42 than the first and second examples while maintaining the heat insulating effect.

  The heat treatment apparatus of the present invention can also be applied to a substrate manufacturing process.

  An example in which the heat treatment apparatus of the present invention is applied to one step of a manufacturing process of a SIMOX wafer which is a kind of SOI (Silicon On Insulator) wafer will be described.

First, oxygen ions are implanted into the single crystal silicon wafer by an ion implantation apparatus or the like. Thereafter, the wafer into which oxygen ions are implanted is annealed at a high temperature of 1300 ° C. to 1400 ° C., for example, 1350 ° C. or higher, for example, in an Ar, O ₂ atmosphere using the heat treatment apparatus of the above embodiment. By these processes, a SIMOX wafer in which the SiO ₂ layer is formed inside the wafer (the SiO ₂ layer is embedded) is manufactured.

  In addition to the SIMOX wafer, the heat treatment apparatus of the present invention can be applied to one step of the manufacturing process of the hydrogen anneal wafer and the Ar anneal wafer. In this case, the wafer is annealed at a high temperature of about 1200 ° C. or higher in a hydrogen atmosphere or an Ar atmosphere using the heat treatment apparatus of the present invention. As a result, crystal defects in the wafer surface layer on which an IC (integrated circuit) is formed can be reduced, and crystal integrity can be improved.

  In addition, the heat treatment apparatus of the present invention can be applied to one step of the epitaxial wafer manufacturing process.

The heat treatment apparatus of the present invention can also be applied to a semiconductor device manufacturing process.
In particular, a heat treatment process performed at a relatively high temperature, for example, a thermal oxidation process such as wet oxidation, dry oxidation, hydrogen combustion oxidation (pyrogenic oxidation), HCl oxidation, boron (B), phosphorus (P), arsenic (As ), An antimony (Sb) or other impurity (dopant) is preferably applied to a thermal diffusion process for diffusing the semiconductor thin film.

1 is a schematic perspective view showing a heat treatment apparatus according to an embodiment of the present invention. It is sectional drawing which shows the reaction furnace used for the heat processing apparatus which concerns on embodiment of this invention. It is sectional drawing which shows the 1st example of the 1st heat insulation part used for the heat processing apparatus which concerns on embodiment of this invention, and a 2nd heat insulation part, and its periphery. It is sectional drawing which shows the 2nd example of the 1st heat insulation part used for the heat processing apparatus which concerns on embodiment of this invention, and a 2nd heat insulation part, and its periphery. It is sectional drawing which shows the detail of the 3rd example of the 1st heat insulation part used for the heat processing apparatus which concerns on embodiment of this invention, and a 2nd heat insulation part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Heat processing apparatus 26 Substrate transfer machine 30 Support tool 40 Reaction furnace 42 Reaction tube 43 Reaction chamber 46 Heater 48 Furnace port cap 50 1st heat insulation part 52 2nd heat insulation part 54 Substrate 56 Gas introduction port 60 Gas introduction pipe 66 Nozzle 68 SiC insulation board (Si impregnation type)
70 Insulating board made of quartz 72 Insulating board made of SiC (high purity SiC)

Claims (2)

A reaction chamber with a furnace port at the lower end;
A support for supporting the substrate in the reaction chamber;
A plurality of silicon carbide heat insulating plates provided in a vertical direction with a first pitch below the support;
A plurality of quartz heat insulating plates provided in a vertical direction with a second pitch below the plurality of silicon carbide heat insulating plates;
A furnace port cap provided below the plurality of quartz heat insulating plates and closing the furnace port of the reaction chamber;
The first pitch of the silicon carbide heat insulating plate is larger than the second pitch of the quartz heat insulating plate, and the thickness of the silicon carbide heat insulating plate is smaller than the thickness of the quartz heat insulating plate. A heat treatment device characterized. A reaction chamber with a furnace port at the lower end;
A support for supporting the substrate in the reaction chamber;
A plurality of silicon carbide heat insulating plates provided in the vertical direction below the support,
A plurality of quartz heat insulating plates provided in the vertical direction below the plurality of silicon carbide heat insulating plates;
A furnace port cap provided below the plurality of quartz heat insulating plates and closing the furnace port of the reaction chamber;
The heat treatment apparatus according to claim 1, wherein a thickness of the silicon carbide heat insulating plate is smaller than a thickness of the quartz heat insulating plate.

Images