JP2006100303A - Substrate manufacturing method and heat treatment apparatus - Google Patents

Abstract

Provided are a heat treatment apparatus and a substrate manufacturing method for manufacturing a high-quality substrate by reducing the generation of scratches on a substrate during heat treatment, suppressing substrate slip, and suppressing substrate warpage.
When a support 30 on which a substrate 54 is placed in a reaction tube 42 is inserted, a set temperature of each heater zone of a heater 46 is set to T5 <T4 <T3 <T2 <T1. After inserting the support tool 30 into the reaction tube 42, first, the set temperature of T5 is increased to be equal to T4 (T5 = T4 <T3 <T2 <T1). Next, the set temperatures of T5 and T4 are raised to be equal to T3 (T5 = T4 = T3 <T2 <T1). Further, the set temperatures of T5, T4, and T3 are increased to be equal to T2 (T5 = T4 = T3 = T2 <T1). Further, the set temperatures of T5, T4, T3, and T2 are increased to be equal to T1 (T5 = T4 = T3 = T2 = T1).
[Selection] Figure 4

Description

  The present invention relates to a substrate manufacturing method including a step of heat-treating a substrate, and a heat treatment apparatus for heat-treating the substrate.

  For example, when a plurality of substrates such as a silicon single crystal wafer is heat-treated using a vertical heat treatment furnace, a predetermined number of substrates are loaded into a vertical boat at room temperature and heated to a temperature of about 700 ° C. in advance. A vertical boat is carried into the reaction tube. Next, the temperature in the reaction tube is raised to a temperature of about 1000 ° C. or higher and heat-treated, and then the temperature in the reaction tube is lowered to a temperature of about 700 ° C., for example, and the vertical boat on which the substrate is placed is unloaded. To do.

In this case, when the substrate is carried in, a large amount of radiant heat is supplied to the periphery of the substrate at room temperature in a short time. In that case, the temperature of the outer peripheral portion of the substrate is high and the temperature of the central portion is low. On the other hand, heat is dissipated from the periphery of the substrate in a short time when the substrate is unloaded. In that case, the temperature is high in the central part of the substrate and the temperature is low in the outer peripheral part. As described above, a temperature difference is generated between the peripheral portion and the central portion in the substrate, the thermal difference is generated in the substrate due to the temperature difference, and the substrate is elastically deformed. By this elastic deformation, rubbing occurs at the contact portion between the substrate and the substrate support, and the substrate can be damaged. The yield stress for the generation of dislocations is significantly reduced in single crystal silicon scratches (see Crystal Engineering and Evaluation Technology No. 145 Committee, 68th Meeting (Kakuno, p4)).
For this reason, during the subsequent temperature raising process or high temperature heat treatment, dislocations occur in the substrate at the scratched part, which becomes a slip, and when the slip becomes large, it becomes a slip line, which is one of the causes of the substrate warping. It was. Further, when the slip line is generated, the flatness of the substrate is lowered. For this reason, in the lithography process, which is one of the important processes in the LSI manufacturing process, mask misalignment (mask misalignment due to defocusing or deformation) occurs, and there is a problem that it is difficult to manufacture an LSI having a desired pattern. Was.
Therefore, by providing a heater for slow heating that is thermally separated from the heater for the heat treatment process in the vicinity of the furnace port, it becomes possible to set the temperature relatively freely, and those that give an arbitrary temperature gradient near the furnace port. It is publicly known (for example, Patent Document 1).

JP-A-5-215463

  However, since the heater for slow heating of Patent Document 1 is installed independently, a temperature difference occurs between the heater for slow heating and the heater for thermal process, or between room temperature and the heater for slow heating. In addition, it is necessary to provide another heater in addition to the heat treatment heater. Further, in order to obtain the effect of the slow heating heater, a certain length is required for the slow heating heater portion, so that the space in the reaction chamber is reduced. It is conceivable that the number of substrates to be processed at one time is reduced and the number of processed substrates is reduced.

  The object of the present invention is to eliminate the above-mentioned conventional problems, reduce the occurrence of substrate scratches during heat treatment, suppress substrate slip, suppress substrate warpage, and manufacture a high-quality substrate. A heat treatment apparatus and a substrate manufacturing method are provided.

  In order to solve the above-mentioned problems, a first feature of the present invention is that a substrate loading step for loading a substrate into a reaction furnace heated by a heater divided into a plurality of zones, and the reaction furnace after loading the substrate. A temperature raising step for raising the internal temperature to a heat treatment temperature, a heat treatment step for heat treating the substrate in the reaction furnace, and a substrate unloading step for unloading the substrate after the heat treatment from the reaction furnace, the substrate loading step Alternatively, in the substrate carry-out step, a temperature gradient is provided by changing the set temperature of each heater zone, and in the temperature raising step, the set temperature of each heater zone is made substantially equal to make the temperature gradient flat. It is in.

  Preferably, in the substrate carry-in step or the substrate carry-out step, the set temperature of each heater zone is reduced as it approaches the furnace port. Preferably, in the temperature raising step, the temperature of the heater zone closest to the furnace port is made equal to the set temperature of the heater zone adjacent thereto, and then the temperature of the heater zone made equal to the set temperature is set adjacent to them. By making this equal to the set temperature of the heater zone to be repeated and repeating this, the set temperature of each heater zone is made substantially equal step by step to flatten the temperature gradient. Preferably, in the temperature raising step, the set temperature of each heater zone is made equal to make the temperature gradient flat, and then the set temperature of the heater is raised stepwise. Preferably, when the substrate is loaded into the reaction furnace, the substrate is loaded while being supported by a support. Preferably, the support is configured to support a plurality of substrates in a plurality of stages with a gap in a substantially horizontal posture. Preferably, the support has a main body part and a support part in contact with the substrate, and the support part is made of a plate-like member. Furthermore, the heat treatment in the present invention is preferably performed at a high temperature of 1200 ° C. or higher, more preferably 1350 ° C. or higher.

  The second feature of the present invention is that a reaction furnace for processing a substrate, a heater divided into a plurality of zones for heating the inside of the reaction furnace, and a loading / unloading means for loading / unloading the substrate into / from the reaction furnace. When the substrate is carried into or out of the reaction furnace, a temperature gradient is provided by changing the set temperature of each heater zone, and when the temperature in the reaction furnace is raised after the substrate is loaded, And a control means for controlling the temperature gradient to be flat by making the set temperatures equal to each other.

  According to the present invention, it is possible to reduce the generation of scratches on the substrate that occurs during heat treatment, suppress the generation of slip lines on the substrate, suppress the warpage of the substrate, and thus provide a high-quality substrate, thereby improving the yield. Thus, cost reduction can be realized.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an example of 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.

  A pod transfer device 18 is disposed on the front side in the housing 12 and 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 shelf 20 is disposed above the pod opener 22, and the substrate number detector 24 is disposed adjacent to the pod opener 22. 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 has, for example, an arm (tweezer) 32 that can take out five substrates. By moving the arm 32, the pod placed at the position of the pod opener 22, the notch aligner 28, and the support are provided. The substrate is transferred between the tools 30. 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. Furthermore, a reaction furnace 40 is disposed at the upper part on the back side in the housing 12. The support 30 loaded with a plurality of substrates is loaded into the reaction furnace 40 and subjected to heat treatment.

  In FIG. 2, an example of the reaction furnace 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 whose upper end is closed and whose lower end is opened, and the opened lower end is formed in a flange shape. A quartz adapter 44 is disposed below the reaction tube 42, and the reaction tube 42 is supported by the adapter 44. The adapter 44 has a cylindrical shape with an open upper end and a lower end, and the opened upper end and the lower end are formed in a flange shape. The lower surface of the lower end flange of the reaction tube 42 is in contact with the upper surface of the upper end flange of the adapter 44. Further, a heater 46 described later is disposed around the reaction tube 42 excluding the adapter 44.

  The lower part of the reaction tube 42 is opened to insert the support 30, and this open part (furnace port part) is in contact with the lower surface of the lower end flange of the adapter 44 with the furnace port seal cap 48 sandwiching the O-ring. It is made to be sealed by. The furnace port seal cap 48 supports the support tool 30 and is provided so as to move up and down together with the support tool 30. Between the furnace port seal cap 48 and the support 30, a second cap 52 made of quartz serving as a second heat insulating portion, and a first heat insulating portion disposed on the upper portion of the second cap 52. A first cap 50 made of SiC 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.

  In order to enable processing at a high temperature of 1200 ° C. or higher, the reaction tube 42 is made of SiC. When this SiC reaction tube 42 is extended to the furnace port, and the SiC furnace port is sealed with a furnace port seal cap 48 via an O-ring, the SiC reaction tube 42 is transmitted via the SiC reaction tube. There is a possibility that the heat will rise to the seal part due to heat and the O-ring which is the seal material will be melted. If the seal part of the reaction tube 42 made of SiC is cooled so as not to melt the O-ring, the reaction tube 42 made of SiC is damaged due to a difference in thermal expansion due to a temperature difference. Therefore, the heating region by the heater 46 is configured by the reaction tube 42 made of SiC, and the portion outside the heating region by the heater 46 is configured by the adapter 44 made of quartz, so that heat is transmitted from the reaction tube 42 made by SiC. It is possible to seal the furnace port without melting the O-ring and damaging the reaction tube 42.

  A gas supply port 56 and a gas exhaust port 58 are formed in the adapter 44 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. Further, the inner wall of the adapter 44 is on the inner side (projects) from the inner wall of the reaction tube 42, and the side wall (thick part) of the adapter 44 communicates with the gas supply port 56 to introduce gas in the vertical direction. A path 64 is provided, and a nozzle mounting hole is formed at an upper portion thereof so as to open upward. The nozzle mounting hole communicates with the gas supply port 56 and the gas introduction path 64. A nozzle 66 is inserted and fixed in the nozzle mounting hole. That is, the nozzle 66 is connected to the upper surface of the portion of the adapter 44 that protrudes inward from the inner wall of the reaction tube 42, and the nozzle 66 is supported by this upper surface. 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 via the gas introduction path 64 and the nozzle 66 provided in the side wall portion of the adapter 44.

  The nozzle 66 is configured to extend vertically from the position of the nozzle mounting hole to above the substrate arrangement region (above the top of the support 30) along the inner wall of the reaction tube 42. The nozzle 66 has an inner diameter of 10 mm and a length of 1000 mm, for example.

  As described above, in the reaction furnace 40, the reaction tube 42 is made of SiC in order to enable processing at a high temperature of 1200 ° C. or higher. For example, an annealing temperature for manufacturing a SIMOX (Separation by Implanted Oxygen) wafer described later is 1350 ° C. or higher. On the other hand, the support tool 30 on which the substrate is supported is made of SiC like the reaction tube 42. In addition, the first heat insulating portion 50 located below is made of SiC, and the second heat insulating portion 52 located below is made of quartz. When the first heat insulating portion 50 is made of quartz, when the processing temperature is 1350 ° C. or higher, the quartz may cause a creep phenomenon and be deformed.

  When the first heat insulating part 50 made of quartz is deformed, the heat insulating effect by the first heat insulating part 50 is lowered, so that the furnace port seal cap 48 becomes high temperature. When the furnace port seal cap 48 reaches a high temperature, an O-ring having a heat resistant temperature of, for example, 250 ° C. melts as a seal material for the furnace port portion, and the shielding property by the furnace port seal cap 48 is lost. Furthermore, due to the deformation of the first heat insulating portion 50, 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 support 30 described above will be described.
In FIG. 3, the support tool 30 includes a main body 68 and a support 70. The main body 68 is made of, for example, silicon carbide, and includes an upper plate 72, a lower plate 74, and a support column 76 that connects the upper plate 72 and the lower plate 74. The main body 68 is formed with a plurality of parallel mounting portions 78 extending from the support column 76 toward the substrate transfer machine 26 described above.

  The support part 70 is made of a plate member made of silicon, and is formed in, for example, a cylindrical shape that is concentric with the substrate 54. The substrate 54 is placed on and supported by the lower surface of the substrate 54 in contact with the upper surface of the support portion 70. The diameter of the support portion 70 is smaller than the diameter of the substrate 54, and the support portion 70 supports the substrate 54 without contacting the peripheral edge portion of the substrate 54.

Next, the heater 46 described above will be described.
In FIG. 4, the heater 46 divided | segmented into the several zone in the reaction furnace 40 mentioned above is shown. The heater 46 is divided into T1, T2, T3, T4 and T5 and five heater zones in order from the top of the reaction furnace 40, and the temperature can be set independently. Can be set. The temperature of the heater 46 is controlled by the control device 100.

Next, the operation of the heat treatment apparatus 10 configured as described above will be described.
In the following description, the operation of each part constituting the heat treatment apparatus is controlled by the control means 100.
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 30, a plurality of substrates are placed in the reaction furnace 40 that has previously been provided with a temperature gradient by varying the set temperature of each heater zone of the heater 46. The loaded support 30 is loaded (substrate loading step), and the inside of the reaction tube 42 is sealed with a furnace port seal cap 48. Next, the set temperature of each heater zone of the heater 46 is made substantially equal, the temperature gradient is made flat, the furnace temperature is raised to the heat treatment temperature (temperature raising step), the gas introduction pipe 60 through the gas introduction port 56, A processing gas is introduced into the reaction tube 42 via a gas introduction path 64 provided on the side wall of the adapter 44 and a nozzle 66 (heat treatment step). 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.

  When the heat treatment of the substrate is completed, the temperature of each heater zone of the heater 46 is made substantially equal to maintain a flat temperature gradient (temperature lowering step), and then the temperature set for each heater zone of the heater 46 is reached. Are provided with a temperature gradient, and in this state, the support 30 supporting the substrate after the heat treatment is unloaded from the reaction furnace 40 (substrate unloading step). The support tool 30 is made to wait at a predetermined position until all the substrates supported by the support tool 30 are cooled. 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.

In the present invention, in the substrate carry-in step or the substrate carry-out step, the set temperature of each heater zone of the heater 46 is varied to provide a temperature gradient in the reaction furnace 40, and in the temperature raising step, the set temperature of each heater zone is substantially equal. Then, the temperature gradient in the reaction furnace 40 is controlled to be flat.
As a method for realizing the temperature gradient (temperature gradient), assuming that the heater structure is the same, (a) a method of controlling the power with a thyristor with a constant current value, and (b) a constant power supply. There are two methods of controlling power with a thyristor, and either method may be used.

Next, temperature control of the heater 46 at the time of carrying in and carrying out the support tool 30 will be described in detail.
As described above, the temperature gradient (temperature gradient) from the upper part to the lower part in the reaction tube 42 corresponding to each heater zone (from the upper part T1, T2, ... T5) of the heater 46 when the support tool 30 is carried in and out. make. For example, the temperature range in the reaction tube 42 corresponding to each heater zone: T1 is 800 ° C to 600 ° C, T2 is 700 ° C to 500 ° C, T3 is 600 ° C to 400 ° C, T4 is 500 ° C to 300 ° C, and T5 is Set to 400 ° C. to 200 ° C. (T1 ≧ T2 ≧ T3 ≧ T4 ≧ T5).
By setting the temperature range of each heater zone as described above, the room temperature substrate 54 placed on the support 30 is moved from the heater zone T5 at the initial stage when the support 30 is started to be inserted into the reaction tube 42. The amount of radiant heat received can be reduced. Therefore, a transient temperature difference between the peripheral portion and the central portion of the substrate 54 can be reduced at the initial stage when the support 30 is inserted into the reaction tube 42.

  When the support tool 30 approaches the heater zone T4 after a certain period of time has elapsed after the support tool 30 starts to be inserted into the reaction tube 42, the amount of radiant heat received from the heater zone T4 received by the peripheral portion of the substrate 54 increases. However, part of the radiant heat received before this stage (heater zone T5) flows from the periphery of the substrate 54 toward the center due to heat conduction in the substrate 54. The temperature has risen to some extent. For this reason, the temperature difference between the peripheral portion and the central portion of the substrate 54 is reduced. Therefore, compared to the conventional method, an increase in radiant heat received from the heater zone T4 (difference between the amount of heat received from the heater zone T4 and the amount of heat received from the heater zone T5, or a difference between the amount of heat received from the heater zone T4 and the amount of heat released from the substrate). As a result, the transient temperature rise in the peripheral portion of the substrate 54 is reduced. Therefore, even after a lapse of a certain time after the support 30 is inserted into the reaction tube 42, a transient temperature difference between the peripheral portion and the central portion of the substrate 54 can be reduced.

  Similarly, when the support tool 30 approaches the heater zone T3 after a certain period of time has elapsed after the support tool 30 starts to be inserted into the reaction tube 42, the amount of radiant heat from the heater zone T3 received by the peripheral portion of the substrate 54 increases. Become. However, a part of the radiant heat received before this stage (heater zone T5 and heater zone T4) flows from the peripheral portion of the substrate 54 toward the central portion due to heat conduction in the substrate 54, so that the substrate 54 The temperature of the central part of the substrate rises to some extent, and the transient temperature difference between the peripheral part and the central part of the substrate is reduced. By repeating this phenomenon, the temperature difference in each substrate 54 is reduced.

  Further, after the support 30 is completely inserted into the reaction tube 42, for example, the heater zones may be set to the same temperature at the same temperature increase rate. For example, the setting of each heater zone when the support tool 30 is inserted is set to T1 = 700 ° C., T2 = 600 ° C., T3 = 500 ° C., T4 = 400 ° C., T5 = 300 ° C. When the temperature is set to 700 ° C. and all the temperature increase rates of each heater zone are set to 20 ° C./min (except for the heater zone T1), the heater zones have the same temperature after 20 minutes.

  As another example, the temperature increase rate of each heater zone may be changed for each heater zone so that all heater zones have the same temperature. For example, the setting of each heater zone when the support tool 30 is inserted is T1 = 700 ° C., T2 = 600 ° C., T3 = 500 ° C., T4 = 400 ° C., T5 = 300 ° C. For example, if the heating rate of the heater zone is T1 = 0 ° C / min, T2 = 5 ° C / min, T3 = 10 ° C / min, T4 = 15 ° C / min, T5 = 20 ° C / min, all after 20 minutes The heater zones have the same temperature.

  By the way, when the support tool 30 is inserted into the reaction tube 42, the lower substrate 54 enters the reaction tube 42 later than the upper stage of the support tool 30. And the temperature in the reaction tube 42 are large. As a method of reducing the temperature difference between the lower substrate 54 and the reaction tube 42 and flattening the temperature gradient of the heater 64, the heater zones T1, T2,. . . There is a method of making the temperature of T5 equal in steps (gradually). That is, the temperature of the heater zone closest to the furnace opening is set equal to the set temperature of one heater zone adjacent thereto, and then the temperature of a plurality of heater zones having the same set temperature is set to one heater zone adjacent thereto. By making this equal to the temperature and repeating this, the set temperature of each heater zone is made equal step by step to flatten the temperature gradient.

  Specifically, when the support tool 30 is inserted into the reaction tube 42, the set temperature of each heater zone is set to T5 <T4 <T3 <T2 <T1. After inserting the support tool 30 into the reaction tube 42, first, the set temperature of T5 is increased to be equal to T4 (T5 = T4 <T3 <T2 <T1). Next, the set temperatures of T5 and T4 are increased to be equal to T3 (T5 = T4 = T3 <T2 <T1). Further, the set temperatures of T5, T4 and T3 are increased to be equal to T2 (T5 = T4 = T3 = T2 <T1). Further, the set temperatures of T5, T4, T3, and T2 are increased to be equal to T1 (T5 = T4 = T3 = T2 = T1). Thus, each heater zone T1, T2,. . . By making the temperature of T5 equal stepwise (gradually), it is possible to suppress the occurrence of a transient temperature difference between the peripheral portion and the central portion even in the lower substrate 54 of the support 30.

  Each heater zone T1, T2,. . . By making the set temperature of T5 equal stepwise (gradually), the temperature in the reaction tube 42 gradually increases. Further, after equalizing the set temperatures of the heater zones and flattening the temperature gradient, the set temperatures of all the heater zones are raised stepwise to raise the temperature in the reaction tube 42 to the processing temperature.

  As described above, the temperature difference between the peripheral part and the central part in the substrate 54 hardly occurs from the start of the insertion of the support 30 into the reaction tube 42 to the completion of the temperature rise of the reaction tube 42, and the elasticity of the substrate 54. Deformation can be prevented. As a result, the possibility of rubbing at the contact portion between the substrate 54 and the support 30 is reduced, and the generation of scratches can be suppressed. Further, not only the local stress concentration in the substrate 54 can be reduced, but also the yield stress due to the occurrence of dislocation due to the presence of flaws can be prevented from decreasing, and the occurrence of slip can be suppressed, thereby suppressing the warpage of the substrate 54. It becomes possible.

  In the case where the support tool 30 is carried out from the reaction tube 42, an operation reverse to the case where the support tool 30 is inserted into the reaction tube 42 is performed. In this case, the action of reducing the temperature difference in the substrate 42 is the same except when the support 30 is inserted into the reaction tube 42 and the direction of the heat flow. That is, when the support tool 30 is inserted into the reaction tube 42, part of the radiant heat flows from the peripheral portion to the center portion of the substrate 42 due to heat conduction, whereas the support tool 30 is carried out of the reaction tube 42. At this time, generation of a transient temperature difference in the substrate 42 is suppressed by heat flowing from the central portion to the peripheral portion in the substrate 42.

  Next, examples and comparative examples will be described.

Using the vertical heat treatment apparatus having the reaction furnace shown in FIG. 4, 50 substrates 54 were placed on the silicon carbide support 30, and heat treatment was performed in the reaction tube 42. The substrate 54 was a silicon substrate having a diameter of 300 mm. The power supply of each heater zone of the heater 46 is controlled, and the temperature setting is set to T1: 700 ° C, T2: 600 ° C, T3: 500 ° C, T4: 400 ° C, T5: 300 ° C. The support 30 was inserted into the reaction tube 42 at a speed of 100 mm / min. After the insertion of the support 30 is completed, first, the set temperature of the heater zone T5 is increased from 300 ° C. to 400 ° C. to be equal to the set temperature of the heater zone T4 (temperature rising time 5 minutes), and then the heater zones T5 and T4 The set temperature of the heater zone is raised from 400 ° C. to 500 ° C. to be equal to the set temperature of the heater zone T3 (heating time 5 minutes), and then the set temperature of the heater zones T5, T4 and T3 is raised from 500 ° C. to 600 ° C. The heater zone T2 is set equal to the set temperature of the heater zone T2 (temperature raising time 5 minutes). The temperature gradient was flattened by equalizing (heating time 5 minutes).
Next, the temperature increase rate of each heater zone was set to 10 ° C./min, the temperature was increased to 1000 ° C., and the temperature range from 1000 ° C. to 1200 ° C. was increased at a temperature increase rate of 1 ° C./min. After heat treatment is performed on the substrate 54 while maintaining at 1200 ° C. for 1 hour, the temperature range of 1200 ° C. to 1000 ° C. is decreased at a temperature decrease rate of 1 ° C./min, and the temperature range of 1000 ° C. to 700 ° C. is decreased to a temperature decrease rate of 10 The temperature was lowered at ° C / min.
Next, the temperature of each heater zone is lowered to T2: 600 ° C., T3: 500 ° C., T4: 400 ° C., T5: 300 ° C. at a temperature lowering rate of 10 to 20 ° C./min. It was carried out from the reaction tube 42.
Then, as a result of observing the back surface of the substrate 54 after the heat treatment with an optical microscope, the occurrence of scratches on the back surface of the substrate 54 was slight (the height of the scratch was 1 μm or less), and no slip was observed. As a result of measuring the warpage of the substrate 54 with a warpage meter, the amount of warpage was 10 μm or less, and no significant change in warpage was observed before and after the heat treatment. The temperature difference in the substrate 54 during this process was about 80 ° C. or less at maximum.

Using the vertical heat treatment apparatus having the reaction furnace shown in FIG. 4, 50 substrates 54 were placed on the silicon carbide support 30 and heat treatment was performed in the reaction furnace 42. The substrate 54 was a silicon substrate having a diameter of 300 mm. The power supply of each heater zone of the heater 46 is controlled, and the temperature setting is set to T1: 800 ° C, T2: 600 ° C, T3: 500 ° C, T4: 400 ° C, T5: 300 ° C. The support 30 was inserted into the reaction tube 42. After the insertion of the support 30 is completed, first, the set temperature of the heater zone T5 is increased from 300 ° C. to 400 ° C. to be equal to the set temperature of the heater zone T4 (temperature rising time 5 minutes), and then the heater zones T5 and T4 The set temperature of the heater zone is raised from 400 ° C. to 500 ° C. to be equal to the set temperature of the heater zone T3 (heating time 5 minutes), and then the set temperature of the heater zones T5, T4 and T3 is raised from 500 ° C. to 600 ° C. The heater zone T2 is set equal to the set temperature of the heater zone T2 (temperature rising time 5 minutes), and then the set temperature of the heater zones T5, T4, T3 and T2 is increased from 600 ° C. to 800 ° C. to set the set temperature of the heater zone T1. (Temperature rising time 10 minutes) and the temperature gradient was flattened.
Next, the temperature increase rate of each heater zone was set to 10 ° C./min, the temperature was increased to 1000 ° C., and the temperature range from 1000 ° C. to 1200 ° C. was increased at a temperature increase rate of 1 ° C./min. After heat treatment is performed on the substrate 54 while maintaining at 1200 ° C. for 1 hour, the temperature range of 1200 ° C. to 1000 ° C. is decreased at a temperature decrease rate of 1 ° C./min, and the temperature range of 1000 ° C. to 700 ° C. is decreased to a temperature decrease rate of 10 The temperature was lowered at ° C / min.
Next, the temperature of each heater zone is lowered to T2: 600 ° C., T3: 500 ° C., T4: 400 ° C., T5: 300 ° C. at a temperature lowering rate of 10 to 20 ° C./min. It was carried out from the reaction tube 42.
Then, as a result of observing the back surface of the substrate 54 after the heat treatment with an optical microscope, the occurrence of scratches on the back surface of the substrate 54 was slight (the height of the scratch was 1 μm or less), and no slip was observed. Note that the temperature difference in the substrate 54 during this process was about 95 ° C. or less at maximum.

Using the vertical heat treatment apparatus having the reaction furnace shown in FIG. 4, 50 substrates 54 were placed on the silicon carbide support 30, and heat treatment was performed in the reaction tube 42. The substrate 54 was a silicon substrate having a diameter of 300 mm. The power supply of each heater zone of the heater 46 is controlled, and the temperature setting is set to T1: 700 ° C, T2: 600 ° C, T3: 600 ° C, T4: 400 ° C, T5: 200 ° C. The support 30 was inserted into the reaction tube 42. After the insertion of the support 30 is completed, first, the set temperature of the heater zone T5 is increased from 200 ° C. to 400 ° C. to be equal to the set temperature of the heater zone T4 (temperature rising time 5 minutes), and then the heater zones T5 and T4 The set temperature of the heater zones T3 and T2 is increased from 400 ° C. to 600 ° C. to be equal to the set temperature of the heater zones T3 and T2 (temperature rise time 5 minutes), and then the set temperatures of the heater zones T5, T4, T3 and T2 are The temperature was raised to 700 ° C. to be equal to the set temperature of the heater zone T1 (temperature raising time 5 minutes), and the temperature gradient was flattened.
Next, the temperature increase rate of each heater zone was set to 10 ° C./min, the temperature was increased to 1000 ° C., and the temperature range from 1000 ° C. to 1350 ° C. was increased at a temperature increase rate of 1 ° C./min. After heat treatment is performed on the substrate 54 while maintaining at 1350 ° C. for several hours, the temperature range of 1350 ° C. to 1000 ° C. is decreased at a temperature decrease rate of 1 ° C./min, and the temperature range of 1000 ° C. to 700 ° C. is decreased to a temperature decrease rate of 10 The temperature was lowered at ° C / min.
Next, the temperature of each heater zone is lowered to T2: 600 ° C., T3: 400 ° C., T4: 400 ° C., T5: 300 ° C. at a temperature lowering rate of 10 to 20 ° C./min, and a temperature gradient is provided. It was carried out from the reaction tube 42.
Then, as a result of observing the back surface of the substrate 54 after the heat treatment with an optical microscope, the occurrence of scratches on the back surface of the substrate 54 was slight (the height of the scratch was 1 μm or less), and no slip was observed. The temperature difference in the substrate 54 during this process was about 80 ° C. or less at maximum.

Using the vertical heat treatment apparatus having the reaction furnace shown in FIG. 4, 50 substrates 54 were placed on the silicon carbide support 30 and heat treatment was performed in the reaction furnace 42. The substrate 54 was a silicon substrate having a diameter of 300 mm. The power supplied to each heater zone of the heater 46 is controlled, and the temperature setting is set to T1: 700 ° C, T2: 600 ° C, T3: 500 ° C, T4: 400 ° C, T5: 200 ° C. The support 30 was inserted into the reaction tube 42. After the insertion of the support 30 is completed, first, the set temperature of the heater zone T5 is increased from 200 ° C. to 400 ° C. to be equal to the set temperature of the heater zone T4 (temperature increase time 10 minutes), and then the heater zones T5 and T4 The set temperature of the heater zone is raised from 400 ° C. to 500 ° C. to be equal to the set temperature of the heater zone T3 (heating time 5 minutes), and then the set temperature of the heater zones T5, T4 and T3 is raised from 500 ° C. to 600 ° C. The heater zone T2 is set equal to the set temperature of the heater zone T2 (temperature raising time 5 minutes). The temperature gradient was flattened by equalizing (heating time 5 minutes).
Next, the temperature increase rate of each heater zone was set to 10 ° C./min, the temperature was increased to 1000 ° C., and the temperature range from 1000 ° C. to 1350 ° C. was increased at a temperature increase rate of 1 ° C./min. After heat treatment is performed on the substrate 54 while maintaining at 1350 ° C. for several hours, the temperature range of 1350 ° C. to 1000 ° C. is decreased at a temperature decrease rate of 1 ° C./min, and the temperature range of 1000 ° C. to 800 ° C. is decreased to a temperature decrease rate of 10 The temperature was lowered at ° C / min.
Next, the temperature of each heater zone is lowered to T2: 600 ° C., T3: 500 ° C., T4: 400 ° C., T5: 300 ° C. at a temperature lowering rate of 10 to 20 ° C./min. It was carried out from the reaction tube 42.
Then, as a result of observing the back surface of the substrate 54 after the heat treatment with an optical microscope, the occurrence of scratches on the back surface of the substrate 54 was slight (the height of the scratch was 1 μm or less), and no slip was observed. Note that the temperature difference in the substrate 54 during this process was about 95 ° C. or less at maximum.

Using the vertical heat treatment apparatus having the reaction furnace shown in FIG. 4, 50 substrates 54 were placed on the silicon carbide support 30 and heat treatment was performed. The substrate 54 was a quartz substrate having a diameter of 300 mm and a thickness of 1 mm. The maximum temperature of the heat treatment temperature was 1050 ° C., and other conditions were the same as in Example 4.
The heat treatment was performed in the same manner as in Example 4, and the back surface of the substrate 54 after the heat treatment was observed with an optical microscope. As a result, the back surface of the substrate 54 was slightly scratched (the height of the scratch was 2 μm or less). Note that the temperature difference in the substrate 54 during this process was about 110 ° C. or less at maximum.

Comparative Example 1
Using the vertical heat treatment apparatus having the reaction furnace shown in FIG. 4, 50 substrates 54 were placed on the silicon carbide support 30 and heat treatment was performed. The substrate 54 was a silicon substrate having a diameter of 300 mm. The set temperature of the heater 46 was 700 ° C., and the support 30 was inserted into the reaction tube 42 at a speed of 100 mm / min.
After the insertion of the support 30 was completed, the heating rate of the heater was set to 10 ° C./min, the temperature was increased to 1000 ° C., and the temperature range from 1000 ° C. to 1200 ° C. was increased at the heating rate of 1 ° C./min. After heat treatment by holding at 1200 ° C. for 1 hour, the temperature range from 1200 ° C. to 1000 ° C. is decreased at a temperature decrease rate of 1 ° C./min, and the temperature range from 1000 ° C. to 700 ° C. is decreased at a temperature decrease rate of 10 ° C./min. Then, the support 30 was carried out from the reaction tube 42.
Thereafter, the back surface of the substrate 54 after the heat treatment was observed with an optical microscope. As a result, scratches (maximum length: about 250 μm, maximum height: about 7 μm) were observed on the back surface of the substrate 54. Many slip lines (length: 3 to 30 mm) were observed in the vicinity of the scratches. As a result of measuring the warpage of the substrate 54 with a warpage meter, the warpage amount was 60 to 70 μm. The maximum temperature difference in the substrate 54 during this process was about 180 ° C.

Comparative Example 2
Using the vertical heat treatment apparatus having the reaction furnace shown in FIG. 4, 50 substrates 54 were placed on the silicon carbide support 30 and heat treatment was performed. The substrate 54 was a silicon substrate having a diameter of 300 mm. The set temperature of the heater 46 was 700 ° C., and the support 30 was inserted into the reaction tube 42 at a speed of 100 mm / min. The set temperature of the heater 46 at the time of carrying out the support tool 30 was 800 ° C., and other conditions were the same as those in Comparative Example 1.
As a result of performing heat treatment in the same manner as in Comparative Example 1 and observing the back surface of the substrate 54 after processing with an optical microscope, scratches were observed at three locations on the back surface of the substrate 54. A number of slip lines (length of 3 to 35 mm) were observed in the vicinity of the scratches. As a result of measuring the warpage of the substrate 54 with a warpage meter, the amount of warpage was 80 to 100 μm. The maximum temperature difference in the substrate 54 during this process was about 190 ° C.

Comparative Example 3
Using the vertical heat treatment apparatus having the reaction furnace shown in FIG. 4, 50 substrates 54 were placed on the silicon carbide support 30 and heat treatment was performed. The substrate 54 was a quartz substrate having a diameter of 300 mm and a thickness of 1 mm. The maximum heat treatment temperature was set to 1050 ° C., and other conditions were the same as those in Comparative Example 1.
Heat treatment was performed in the same manner as in Comparative Example 1, and the back surface of the substrate 54 after the heat treatment was observed with an optical microscope. As a result, scratches (maximum length of about 80 μm, maximum height of about 10 μm) were observed on the back surface of the substrate 54. Occurrence was seen.

  In the description of the above embodiment and examples, a batch-type apparatus for heat-treating a plurality of substrates was used as the heat treatment apparatus, but the present invention is not limited to this, and a single-wafer type is used. Also good.

  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 a SiO 2 layer is formed inside the wafer (an SiO 2 layer is embedded) is produced.

  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 support tool used for the heat processing apparatus which concerns on embodiment of this invention. It is sectional drawing which shows the heater of the reaction furnace used for the heat processing apparatus which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Heat processing apparatus 26 Substrate transfer machine 30 Support tool 40 Reaction furnace 42 Reaction tube 46 Heater 54 Substrate 100 Control means

Claims (2)

A substrate loading step of loading the substrate into a reaction furnace heated by a heater divided into a plurality of zones;
A temperature raising step for raising the temperature in the reaction furnace to the heat treatment temperature after carrying the substrate;
A heat treatment step of heat treating the substrate in the reaction furnace;
A substrate unloading step of unloading the substrate after the heat treatment from the reaction furnace,
In the substrate carry-in step or the substrate carry-out step, a temperature gradient is provided by changing the set temperature of each heater zone, and in the temperature raising step, the set temperature of each heater zone is made substantially equal to flatten the temperature gradient. A method for manufacturing a substrate, comprising: A reactor for processing substrates;
A heater divided into a plurality of zones for heating the inside of the reaction furnace;
Loading / unloading means for loading / unloading the substrate into / from the reaction furnace;
When loading / unloading the substrate into / from the reaction furnace, a temperature gradient is provided by changing the set temperature of each heater zone, and when raising the temperature in the reaction furnace after loading the substrate, the setting of each heater zone is performed. Control means for controlling the temperatures to be substantially equal and the temperature gradient to be flat; and
The heat processing apparatus characterized by having.

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