JP2006024806A - Substrate processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate processor having a temperature control function for holding a wafer at a prescribed temperature regardless of a great change of the gas flow rate. <P>SOLUTION: The relation of the temperature in a reactor tube 4 detected by an internal TC 7 and the flow rate of a gas to be fed into the reactor tube 4 from a gas inlet 6 to the temperature of a wafer 3 is previously recorded in data. A target temperature set value and a temperature correcting value for correcting the deviation from the temperature of the wafer 3 are previously recorded. A temperature correcting value for each zone is set at every gas flow rate and recoded on a table. For executing a heat treating process, the target temperature is corrected by a temperature correcting value corresponding to the feed rate of the gas from the gas inlet pipe 6. This holds the wafer 3 at a prescribed temperature regardless of a great change of the flow rate of the gas fed from the gas inlet pipe 6. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a substrate processing apparatus such as a batch type semiconductor manufacturing apparatus capable of performing temperature control of an electric furnace, and more particularly, a substrate (hereinafter referred to as a wafer) while performing temperature control in a reaction chamber constituted by the electric furnace. The present invention relates to a substrate processing apparatus that performs a film forming process.

For example, in a semiconductor manufacturing apparatus as a substrate processing apparatus, it is necessary to appropriately control the temperature in the reaction chamber in the semiconductor manufacturing apparatus in order to improve the wafer manufacturing yield, and various techniques relating to such reaction chamber temperature control are reported. Has been. For example, the following Patent Document 1 discloses a technique that allows a wafer to be heat-treated at an appropriate target temperature without being a skilled worker by performing temperature control while adjusting the temperature inside the reaction chamber with a computer system. It is disclosed. According to this technique, the temperature at the position of each wafer placed in a plurality of heating zones in the reaction chamber is individually detected, and the target temperature is between the maximum value and the minimum value of the detected plurality of detection temperatures. Since the temperature in the reaction chamber is automatically controlled by controlling the heating device so as to be included, an optimum heat treatment can be performed on the wafer regardless of the skill level of the operator.
JP 2002-175123 A

  However, since an annealing process for wafer deposition is usually performed while flowing a reaction gas or an inert gas into the reaction chamber, the amount of heat exchange in the reaction chamber changes when the gas flow rate changes greatly. For this reason, it is necessary to drop a large amount of heat into the reaction chamber, but there is a possibility that the temperature of the wafer may change due to a time delay in the temperature rise in the reaction chamber with respect to the dropping of the heat amount. If the temperature of the wafer changes, the film thickness and electrical / mechanical characteristics of the wafer may be affected. For this reason, it is important that the wafer temperature is maintained at a predetermined temperature even if the gas flow rate changes. However, in the above-mentioned conventional technology, the wafer temperature changes when the gas flow rate changes. There is.

  The present invention has been made in view of the above problems, and provides a substrate processing apparatus having a control function that maintains the wafer temperature at a predetermined temperature even if the gas flow rate changes greatly. The purpose is to do.

  In order to solve the above-described problems, a substrate processing apparatus according to the present invention is a substrate processing apparatus that performs a film forming process on a substrate (wafer 3) while controlling the temperature in a reaction chamber, and is a substrate accommodated in the processing chamber. Gas supply means (heater 1), temperature detection means (internal TC7) for detecting the temperature in the processing chamber, and gas supply means (gas inlet 6) for supplying gas into the processing chamber. The correlation between the gas flow rate supplied by the temperature detection means, the temperature change amount detected by the temperature detection means, and the change amount in which the temperature of the substrate changes is obtained in advance, and the correlation and the gas flow rate and the temperature detected by the temperature detection means The temperature of the substrate is obtained based on the above.

  According to such a configuration, the target temperature is corrected by the temperature correction value corresponding to the gas supply flow rate, so that the wafer temperature can be maintained at a predetermined temperature even if the gas flow rate changes greatly. Therefore, the product yield of the substrate can be improved.

  According to the substrate processing apparatus of the present invention, the relationship between the temperature in the reaction chamber, the gas flow rate, and the wafer temperature is acquired in advance as a correction value, and in the actual processing process, the temperature is corrected according to the gas flow rate. As a result, the temperature of the wafer can be stabilized at a preset temperature target value, and as a result, the manufacturing quality of the wafer can be stabilized.

  Hereinafter, embodiments of the present invention will be described in detail by taking a semiconductor manufacturing apparatus as a substrate processing apparatus as an example with reference to the drawings. FIG. 1 is a cross-sectional view of a reaction chamber applied to a general semiconductor manufacturing apparatus. In FIG. 1, a plurality of wafers (semiconductor substrates) 3 are placed in a multistage manner on a boat 2 stored in a reaction vessel 4. Further, a heater 1 is provided outside the reaction tube 4, and further, a gas inlet 6 for introducing a reaction gas and a gas exhaust for discharging a processed gas are provided below the reaction tube 4. A mouth 5 is provided.

  Next, a procedure for processing the wafer 3 in the reaction chamber shown in FIG. 1 will be described. The boat 2 is located below the reaction tube 4 before starting the processing of the wafer 3. Therefore, after a plurality of wafers 3 are stored in the boat 2 by a wafer transfer mechanism (not shown), the boat 2 is stored in the reaction tube 4 by a boat lifting mechanism (not shown). In this state, the treated gas is exhausted from the gas exhaust port 5 while introducing the reaction gas from the gas introduction port 6, and the inside of the reaction tube 4 is adjusted to a predetermined pressure. At this time, the reaction gas passes through the surface of the wafer 3 on the boat 2 and is exhausted from the gas exhaust port 5. Thereafter, the temperature of the heater 1 is raised and the inside of the reaction tube 4 is heated to a predetermined temperature. The target value of pressure and the target value of temperature in the reaction tube 4 are set in advance.

  In the reaction tube 4 brought to a predetermined pressure and temperature in this way, a film forming process proceeds on the surface of the heated wafer 3. When the film formation process is completed by maintaining this state for a predetermined time, the boat 2 is lowered by the boat lifting mechanism by a procedure reverse to that for storing the boat 2 in the reaction tube 4, and then the wafer 3 is taken out from the boat 2. Then, a series of wafer film forming processes is completed.

  In the case of the vertical semiconductor manufacturing apparatus shown in FIG. 1, since the mounting range of the wafer 3 is long in the vertical direction, the temperature of the wafer 3 at each mounting position of the wafer 3 may be uneven. Therefore, the heater element wire 1a of the heater 1 is divided in the vertical direction, and these heater element wires 1a are separately controlled by the heater controller 13, whereby a uniform temperature state is obtained over the entire range where the wafer 3 is placed. To ensure.

  FIG. 2 is a block diagram of the control system in the reaction chamber shown in FIG. That is, as shown in FIG. 2, the temperature controller 12 shown in FIG. 1 is connected to the apparatus operation unit 11. In addition to the temperature controller 12, a pressure controller and other various controllers are connected to the device operation unit 11. However, these controllers are not directly related to the present invention, and thus description thereof is omitted.

  Each component shown in FIG. 2 is connected by using a communication circuit such as a LAN or start-stop synchronization, and information is exchanged between the components. Here, the apparatus operation unit 11 has functions for interfacing with an operator, such as operations for operating a semiconductor manufacturing apparatus, input and storage of various settings, and automatic operation control.

  The temperature controller 12 receives the control target temperature value from the device operation unit 11, detects the current temperature from the temperature sensors, that is, the internal TC (internal thermocouple) 7 and the external TC (external thermocouple) 8, and controls the control target temperature value PID (Proportion Integral Differential) calculation or the like is performed so that the detected temperature of the internal TC 7 and the detected temperature of the internal TC 7 coincide with each other, a heater output signal is calculated as a control amount, and is output to the heater controller 13. The temperature controller 12 also performs processing such as storing a temperature history.

  The heater controller 13 receives a heater output signal from the temperature controller 12, calculates an output value to the heater 1 based on the heater output signal, and then supplies desired power to the heater 1. Thereby, each heater element wire 1a performs heating control of the reaction tube 4 based on a desired power supply amount. In the semiconductor manufacturing apparatus, the temperature condition in the reaction tube 4 is extremely important, and the accuracy of the target temperature by the temperature control as described above greatly affects the uniformity of the wafer film.

  FIG. 3 is a block diagram of the temperature control system in the reaction chamber shown in FIG. For the temperature control in the reaction tube 4 as described above, for example, a PID cascade control system such as the temperature control system of FIG. 3 is used. Here, if the wafer temperature and the temperature of the internal TC 7 do not match, the temperature of the internal TC 7 may be corrected so that the wafer temperature matches the control target temperature value (set temperature). For example, as a preparation before actually manufacturing and processing a product (wafer), a wafer with a thermocouple is placed in the U, CU, CL, and L zones, which are heating zones in the reaction tube 4, and the cascade thermocouple is set to a target temperature. The target temperature of the cascade thermocouple in each zone can be corrected based on the difference between the target temperature and the detected temperature of the thermocouple attached to the wafer obtained in the control.

  FIG. 4 shows an example of the temperature characteristics during the annealing process for film formation of the wafer processed in the reaction chamber shown in FIG. 1, with the horizontal axis representing time (minutes) and the vertical axis representing temperature (° C.). In this example, a relatively low temperature (450 ° C.) is set as a predetermined target set temperature, and the boat 2 on which the product wafers are transferred while the temperature is stabilized at the target set temperature (450 ° C.) is stored in the reaction tube 4. Annealing treatment is performed.

  In such a case, during the annealing process for forming a film on the wafer 3, the process is performed while a reaction gas or an inert gas is allowed to flow inside the reaction tube 4. However, if the gas flow rate changes greatly at this time, the amount of heat exchange in the reaction tube 4 changes, so that it is necessary to drop a larger amount of heat from the heater 1, and as a result, the temperature of the wafer 3 changes. It may end up. Thus, when the temperature of the wafer 3 changes, the film thickness of the wafer 3 varies, and the electrical and mechanical characteristics of the wafer 3 become unstable.

  Therefore, in the embodiment, control is performed so that the temperature of the wafer 3 becomes a predetermined temperature even if the gas flow rate changes greatly. That is, in the semiconductor manufacturing apparatus of the embodiment, the relationship between the temperature, the gas flow rate, and the wafer temperature is recorded in advance in the data. Next, a temperature correction value for correcting a deviation between the target temperature setting value and the wafer temperature is recorded. FIG. 5 is a diagram showing a table of temperature correction values used in the reaction chamber of the semiconductor manufacturing apparatus in the embodiment. As shown in FIG. 5, the temperature correction value for each zone is set for each gas flow rate and recorded in a table.

  For example, when the gas flow rate is 5 L (liter), the temperature correction value for the U zone is −3.2 ° C., the temperature correction value for the CL zone is −2.0 ° C., and when the gas flow rate is 20 L, the CU The temperature correction value for the zone is −7.3 ° C., and the temperature correction value for the L zone is −12.8 ° C. In the case of a negative temperature correction value, the temperature correction value is subtracted from the target temperature setting value. In the case of a positive temperature correction value, the value obtained by adding the temperature correction value to the target temperature setting value is the corrected target temperature setting value. It becomes.

When the temperature is actually controlled, the reaction tube 4 is divided into a plurality of zones, so that there is a temperature interference between the zones. Therefore, the correction temperature is calculated using the interference matrix method used in the soaking length profile correction, and the temperature correction value of each zone is obtained. The interference matrix method is, for example, a matrix of coefficients indicating the degree of influence of a change in target temperature with respect to a cascade thermocouple on the detected temperature of a wafer with a thermocouple. (For details, see Patent Document 1 introduced above)
Further, when the actual process is performed, the temperature of the internal TC 7 is corrected with the temperature correction value obtained according to the temperature and the gas flow rate. As a result, even if the gas flow rate changes, the temperature of the wafer 3 can be processed at the target temperature.

  Next, temperature control of the reaction chamber in the embodiment will be described using examples. First, a desired temperature and flow rate are given in advance in the reaction tube 4, and the wafer temperature at that time is recorded. FIG. 6 is a characteristic diagram of the internal TC temperature and the wafer temperature when the temperature of the internal TC is controlled without performing temperature correction when the gas flow rate is 20 L and the temperature set value is 450 ° C. FIG. 7 is a characteristic diagram of the internal TC temperature and the wafer temperature when the gas flow rate is 10 L and the temperature set value is 450 ° C., and the temperature of the internal TC is controlled without performing temperature correction. 6 and 7, the horizontal axis indicates time (minutes) and the vertical axis indicates temperature (° C.).

  In the case of a gas flow rate of 20 L in FIG. 6, at time 24 minutes, the wafer 3 is placed in the reaction tube 4 and the target temperature is set to 450 ° C., and the inside of the reaction chamber 4 is heated by the heater 1. At this time, the temperature of the wafer 3 becomes 462 ° C. with respect to the temperature set value 450 ° C., and the temperature difference becomes −12 ° C.

  On the other hand, in the case of a gas flow rate of 10 L in FIG. 7, at time 24 minutes, the wafer 3 is placed in the reaction chamber 4 and the target temperature is set to 450 ° C., and the reaction chamber 4 is heated by the heater 1. To do. At this time, the temperature of the wafer 3 is 455 ° C. with respect to the temperature set value 450 ° C., and the temperature difference is −5 ° C.

  Therefore, for example, when the gas flow rate is 20 L, the temperature of the internal TC 7 is controlled at 438 ° C. by subtracting 12 ° C. as the correction value for the temperature of the internal TC 7, and as a result, the wafer The temperature of 3 can be expected to be 450 ° C. On the other hand, when the gas flow rate is 10 L, the temperature of the internal TC 7 is controlled at 445 ° C. by controlling the temperature of the internal TC 7 by subtracting 5 ° C. as a correction value. It can be expected to be 450 ° C.

  FIG. 8 is a characteristic diagram of the internal TC temperature and the wafer temperature when temperature correction is performed and the temperature of the internal TC is controlled when the gas flow rate is 10 L and the temperature set value is 450 ° C. That is, as a result of controlling by adding a correction value of 5 ° C. at a temperature setting value of 450 ° C. and a gas flow rate of 10 L, it can be seen that the temperature of the wafer 3 is stable at the temperature setting value of 450 ° C. Further, when the gas flow rate is 15 L, it can be dealt with by interpolating and using the correction values of 10 L and 20 L. That is, when the gas flow rate is between 10L and 20L, the correction ratio can be determined by weighting, or the correction value can be determined by simple proportionality.

  As described above, the semiconductor manufacturing apparatus in the present embodiment is detected by the internal thermocouple (internal TC) inserted into the reaction tube corresponding to each zone by the heating element divided into a plurality of zones. A batch type semiconductor manufacturing apparatus for controlling the temperature of the wafer, wherein the relationship between the gas flow rate, the internal thermocouple temperature, and the variation in the wafer temperature is obtained in advance as a related expression, and the wafer flow rate and the internal thermocouple temperature are The temperature change amount is calculated.

  In addition, the semiconductor manufacturing apparatus in the present embodiment calculates the amount of change in internal thermocouple temperature necessary to bring the wafer temperature to the target temperature from the above relational expression. Further, the amount of change in the temperature of the internal thermocouple necessary for setting the wafer temperature to the target temperature is calculated from the above-mentioned relational expression, and the amount of change is corrected as the amount of correction of the temperature set value.

  From the above description, the semiconductor manufacturing apparatus of the embodiment can be configured as follows. That is, a heating means (heater 1) for heating the semiconductor substrate (wafer 3) accommodated in the processing chamber, a heating control means (heater controller 13) for controlling the heating means, and a position between the semiconductor substrate and the heating means. Temperature detecting means (internal TC7) for detecting the temperature in the processing chamber, substrate temperature detecting means for detecting the temperature of the semiconductor substrate at the position where the semiconductor substrate is accommodated, and gas supply means for supplying gas into the processing chamber ( Before the semiconductor substrate is processed, the heating control means controls the heating means so that the detected temperature of the temperature detecting means becomes a preset temperature, and the substrate temperature detecting means at that time Measure the temperature detected by the temperature detection means and the temperature detected by the temperature detection means, and further change the gas flow rate supplied by the gas supply means in that state, The temperature difference between the output temperature and the temperature detected by each substrate temperature detecting means is obtained, the gas flow rate, the set temperature and the temperature difference are stored in association with each other, and the substrate temperature detecting means is used when processing the semiconductor substrate. The temperature difference is selected from the relationship between the gas flow rate and the set temperature and the temperature difference stored in advance from the gas flow rate and the set temperature to be removed from the processing chamber, and the temperature difference is set to the set temperature. The heating control means controls the heating means so that the set temperature after the addition is obtained.

  According to the embodiment, the present invention discloses a method for manufacturing a substrate (semiconductor substrate). That is, a heating means (heater 1) for heating the substrate accommodated in the processing chamber, a temperature detection means (internal TC7) for detecting the temperature in the processing chamber, and a gas supply means (gas introduction port) for supplying gas into the processing chamber 6) including a step of heating the substrate by the heating means, a step of supplying the gas by the gas supply means, and a temperature detecting means for detecting the temperature in the processing chamber. A step of obtaining a correlation between a gas flow rate supplied by the gas supply means, a temperature change amount detected by the temperature detection means, and a change amount by which the temperature of the substrate changes, and the correlation and gas flow rate and temperature detection And a step of determining the temperature of the substrate based on the temperature detected by the means.

It is sectional drawing of the reaction chamber applied to a general semiconductor manufacturing apparatus. It is a block diagram of the control system in the reaction chamber shown in FIG. It is a block diagram of the temperature control system in the reaction chamber shown in FIG. It is an example of the temperature characteristic at the time of the annealing process of the wafer film processing processed by the reaction chamber shown in FIG. It is a figure which shows the table of the temperature correction value used for the reaction chamber of the semiconductor manufacturing apparatus in this Embodiment. FIG. 5 is a characteristic diagram of internal TC temperature and wafer temperature when the temperature of internal TC is controlled without performing temperature correction when the gas flow rate is 20 L and the temperature set value is 450 ° C. FIG. 5 is a characteristic diagram of the internal TC temperature and the wafer temperature when the temperature of the internal TC is controlled without performing temperature correction when the gas flow rate is 10 L and the temperature set value is 450 ° C. FIG. 6 is a characteristic diagram of the internal TC temperature and the wafer temperature when temperature correction is performed and the temperature of the internal TC is controlled when the gas flow rate is 10 L and the temperature set value is 450 ° C.

Explanation of symbols

1 Heater 1a Heater Wire 2 Boat 3 Wafer 4 Reaction Tube 5 Gas Exhaust Port 6 Gas Inlet Port 7 Internal TC (Internal Thermocouple)
8 External TC (Internal thermocouple)
11 Device Operation Unit 12 Temperature Controller 13 Heater Controller

Claims (1)

Heating means for heating the substrate accommodated in the processing chamber;
Temperature detecting means for detecting the temperature in the processing chamber;
Gas supply means for supplying gas into the processing chamber,
A correlation between a gas flow rate supplied by the gas supply unit, a temperature change amount detected by the temperature detection unit, and a change amount by which the temperature of the substrate changes is obtained in advance, and the correlation and the gas flow rate A substrate processing apparatus, wherein the temperature of the substrate is obtained based on the temperature detected by the temperature detecting means.

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