JP2005166916A - Manufacturing method of semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the absoluteness of a profile measuring temperature in a furnace by reducing the affection to the temperature measurement in the furnace due to the damage of surface of a reaction furnace which is received in cleaning. <P>SOLUTION: A profile thermo-couple is installed between wafer supporting plates (step 101). Two sheets of wafer-shape soaking plates are carried into the furnace to mount on the wafer mounting unit of the wafer supporting plates (step 102). A temperature profile in the furnace is obtained in a space pinched by two sheets of soaking plates (step 103). After obtaining the temperature profile, two sheets of soaking plates are carried out of the reaction furnace to the outside of the furnace (step 104). The profile thermo-couple is withdrawn out of the furnace (step 105). A film forming process is effected while controlling the temperature of a heater employing the temperature profile (step 107). The wafer, whose treatment is finished, is carried out of the reaction furnace (step 110). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for preventing the influence of radiation from the surface of a reaction furnace when measuring the temperature in the furnace.

In the manufacture of semiconductor elements, various vacuum processing apparatuses such as a CVD apparatus and an etching apparatus are used as processing apparatuses for creating a circuit on a wafer. In the process of processing a wafer by these apparatuses, fine dust due to reaction by-products generated in a processing chamber of a reaction furnace constituting the apparatus adheres to the wafer surface. This is the main cause of the yield of the manufacturing process of the semiconductor element and the reduction of the device operation rate.
Therefore, in order to reduce dust adhering to the wafer surface, reaction by-products deposited on the wall surface of the processing chamber by film formation are appropriately cleaned (removed).

  As a known technique of a reactor relating to such film formation and cleaning, for example, there is one described in Patent Document 1. In this known technique, a flat reaction tube made of quartz or the like (hereinafter also referred to as a reaction furnace or simply a furnace) is provided in a heating space formed by two parallel plate heaters (heating sources). A semiconductor wafer is placed on a wafer support plate that is arranged inside the reaction tube and has a circular portion substantially corresponding to the wafer region cut out, and is exhausted while supplying the gas into the processing chamber while heating the wafer. Thereby, thin film formation (or epitaxial growth) is performed on the wafer surface. When this film forming process is repeated and reaction by-products are deposited on the reaction tube wall surface or gas exhaust part, the amount exceeds the limit value (thickness) and the deposit comes to peel off. First, dry cleaning by gas reaction is performed as appropriate, and after performing this for a predetermined number of times, deposits are further removed by wet cleaning.

  As a specific example of the known example, there is a reaction furnace of a two-wafer semiconductor wafer processing apparatus as shown in FIGS. The two parallel plate heaters 1 described above are further divided into a plurality of zones, and each zone heater is independently temperature controlled. A thermocouple as a temperature sensor for performing temperature control includes a heater thermocouple 2 that measures the temperature in each of the divided heaters 1 and a profile thermocouple 5 that monitors the temperature of the internal wafer region of the quartz reaction tube 3. And are used. The temperature of the heater 1 is controlled by selecting one of the thermocouples 2 and 5 when acquiring the temperature profile and when processing the wafer.

  The wafer W is held horizontally on a rectangular wafer support plate 4 provided in the reaction tube 3. Gas inlet / exhaust ports 6 are provided at both ends of the reaction tube 3. A gate valve 7 is provided at one end of the quartz reaction tube 3 so as to be freely opened and closed. Further, as shown in FIG. 7, the profile thermocouple 5 is provided in each of the three temperature probes 8, and is parallel to each other from the flange surface opposite to the surface on which the gate valve 7 is provided to the wafer region in the reaction tube. It is inserted and fixed, and the inside of the furnace is vacuum sealed.

  FIG. 8 shows a schematic diagram of the main part of the reactor described above. This is a longitudinal sectional view along the tube axis of the flat reaction tube 3. A reaction tube 3 is disposed between the two parallel plate heaters 1. Two wafer support plates 4 are provided in the reaction tube 3 in two upper and lower stages. The wafer support plate 4 is a square quartz plate (see FIG. 7). A wafer mounting portion 10 is provided on the wafer support plate 4. In this wafer mounting portion 10, a circular wafer hole 11 serving as a wafer region having a slightly larger diameter than the wafer is formed in the central portion of the wafer support plate 4, and a plurality of wafer support claws are formed on the outer periphery of the bottom portion of the wafer hole 11. 12 is provided. Two wafers fitted in the wafer hole 11 are supported by the plurality of support claws 12 and held by the wafer support plate 4.

  A plurality of heater thermocouples 2 for measuring the temperature in the heater 1 are installed at predetermined positions in the two parallel plate heaters 1. A plurality of profile thermocouples 5 for measuring the temperature of the wafer region inside the reaction tube are installed between the quartz reaction tube 3 and one of the two wafer support plates 4. In FIG. 8, small black squares repeatedly drawn along the surface of the reaction tube 3 mean the degree of unevenness of the reaction furnace surface described later.

When wafer processing is performed in this reaction furnace, first, the output of the heater 1 is controlled by the control unit 13 so that the internal temperature of the reaction tube 3, that is, the wafer processing temperature, becomes a predetermined temperature using the profile thermocouple 5 described above. . After the reaction tube internal temperature is stabilized, the heater temperature at that time is recorded (acquisition of temperature profile), and when performing wafer processing thereafter, the furnace is used based on the heater thermocouple 2 in each heater 1 using the acquired temperature profile. Control the temperature inside.
JP-A-7-94419 (FIGS. 1 and 2)

However, when the film forming process is repeatedly performed in the semiconductor wafer processing apparatus of Patent Document 1, reaction by-products are deposited on the inner wall of the reaction tube, the wafer support part, and the gas exhaust part. In order to remove these reaction by-products, for example, when dry cleaning is performed with a reaction gas, the reaction tube surface is damaged due to the difference in etching rate between the deposited deposit and the quartz reaction tube. As a result, the unevenness of the reaction tube surface increases. In addition, wet cleaning is performed after dry cleaning is repeated several times. For example, when the reaction tube is wet cleaned with a chemical solution containing hydrofluoric acid (HF) or nitric acid (HFNO ₃ ), the reaction tube is similarly treated. It is known that the unevenness of the surface increases.

While the damage to the reaction tube increases as the cleaning is repeated, the wafer processing temperature calibration is periodically repeated by acquiring the temperature profile, and film formation is performed according to the calibration temperature. For example, FIG. 9 shows the result of forming a silicon film at a temperature of 614 ° C., a SiH ₄ gas flow rate of 60 sccm, a pressure of 0.13 Pa, and a time of 20 minutes.

From FIG. 9, when WET cleaning (wet cleaning) and several ClF ₃ gas cleanings are repeated, the temperature profile value (Profile TC (thermocouple) monitor temperature) plotted with white circles is almost constant. On the other hand, it can be seen that the silicon film thickness (Seed film thickness conversion temperature) plotted with squares actually deposited on the wafer decreases. The Seed film thickness conversion temperature is a film formation temperature when a film having a predetermined film thickness is formed on a wafer.

  A decrease in Seed film thickness conversion temperature with respect to a substantially constant temperature profile value means that there is a deviation between the wafer temperature and the temperature profile value. The cause is presumed that the radiation light scattering factor due to the change in the roughness of the quartz surface deteriorates the absolute value of the temperature monitor value of the profile thermocouple. This is because the profile thermocouple is installed in the space between the quartz reaction tube and the wafer support plate, and the furnace temperature measured by the profile thermocouple is the result of the scattering of radiation from one surface of the quartz reaction tube. This is because it is not only directly affected but also affected by radiant light scattering from the other surface of the quartz reaction tube through the wafer hole of the reaction tube wafer support plate.

  When the film formation reproducibility deterioration due to the cleaning damage on the surface of the quartz reaction tube as described above occurs, the yield of the produced semiconductor device is lowered. As a countermeasure, it is possible to reduce the replacement frequency of the quartz reaction tube. However, this method is inefficient because the running cost is increased and the apparatus stop time due to the replacement of the reaction tube is remarkably increased, and the operation rate of the apparatus is lowered.

  The subject of this invention is providing the manufacturing method of the semiconductor device which can reduce the film-forming reproducibility degradation by the damage of the reactor surface after cleaning, without reducing an operation rate.

  The first invention includes a step of bringing at least two soaking plates into a reaction furnace, a step of measuring a furnace temperature in a space sandwiched between the two soaking plates, and after the temperature measuring step A step of taking out the two soaking plates from the reaction furnace, a step of carrying a substrate into the reaction furnace in a state where the soaking plate is taken out of the reaction furnace, and a temperature measurement in the reaction furnace. A method for manufacturing a semiconductor device, comprising: a step of processing a substrate using a result; and a step of unloading a substrate that has been processed from the reaction furnace.

  Since the in-furnace temperature is measured in a space sandwiched between at least two soaking plates, the in-furnace measurement temperature is not affected by the reaction furnace surface, and the absolute value of the in-furnace temperature value is improved. Therefore, even if the surface of the reaction furnace is damaged by cleaning the reaction furnace, substrate processing with good film reproducibility can be performed in the reaction furnace using the result of temperature measurement with improved absoluteity. As a result, it is possible to suppress a decrease in yield due to film formation reproducibility deterioration. In addition, since the frequency of replacement of the reactor is reduced, running cost can be reduced and productivity can be improved.

  A second invention is the method of manufacturing a semiconductor device according to the first invention, wherein the space is formed by holding the at least two soaking plates with a support that supports a substrate. is there. When a space is formed by holding at least two soaking plates with a support that supports the substrate, a step similar to the step of supporting at least two substrates on the support that supports the substrate is performed. A space can be easily formed only by carrying out.

  A third invention is the method of manufacturing a semiconductor device according to the first or second invention, wherein the heat equalizing plate is made of silicon or SiC. If the material of the soaking plate is silicon or SiC in particular, these have low infrared transmittance and are not affected by radiation from the surface of the reaction furnace, so that the absolute value of the temperature value in the furnace is further improved.

  A fourth invention is a method of manufacturing a semiconductor device according to any one of the first to third inventions, wherein the soaking plate has substantially the same shape as the substrate. If the heat equalizing plate has approximately the same shape as the substrate, the space can be easily formed by simply performing the step of supporting the two substrates on the heat equalizing plate as it is by supporting the substrate.

  According to a fifth invention, in the first to fourth inventions, in the space sandwiched between at least two soaking plates in the reaction furnace before or after carrying at least two soaking plates into the reaction furnace. A method of manufacturing a semiconductor device, comprising the step of inserting a temperature measuring means composed of a thermocouple or the like, and measuring the temperature in the furnace by the temperature measuring means. Before or after the at least two soaking plates are carried into the reaction furnace, the step of inserting the temperature measuring means into the space sandwiched between the at least two soaking plates in the reaction furnace has at least two soaking plates. The process of measuring the furnace temperature can be easily performed in the space sandwiched between the hot plates.

  A sixth invention includes a reaction furnace that accommodates a substrate, a heater that heats the reaction furnace, heater temperature measuring means that measures the temperature of the heater, two soaking plates for the inside of the reaction furnace, Conveying means for carrying in and out the substrate, furnace temperature measuring means for measuring the furnace temperature in a space sandwiched between two soaking plates carried into the reactor, the output of the heater and the Control means for controlling the transfer means, the control means measures the temperature in the furnace heated by the heater at the time of measuring the furnace temperature by means of the furnace temperature measuring means, and the furnace temperature measuring means at the time of substrate processing The heater output is controlled using the result of the measured furnace temperature, and after the furnace temperature measurement, the two soaking plates are taken out from the reactor, and the soaking plate is used as a reactor. In the reactor in the state of being taken out more A board is carried in, the substrate is processed in the reaction furnace using the result of the temperature measurement in the furnace, and the transfer means is controlled so as to carry out the processed substrate from the reaction furnace. Is a substrate processing apparatus. If a control means for controlling the heater output and the conveying means is provided, the first invention can be easily implemented.

  According to the present invention, since the absolute value of the in-furnace temperature value to be measured is improved, even if the reaction furnace surface is damaged, it is possible to suppress a decrease in yield due to film formation reproducibility degradation. Further, since the frequency of replacement of the reactor is reduced, the running cost can be reduced and the productivity can be improved.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 5 is a schematic longitudinal sectional view of a reaction furnace constituting a two-wafer substrate processing apparatus for carrying out the semiconductor device manufacturing method of the present invention.

  The reaction tube 203 as a quartz reaction vessel has a flat space in the horizontal direction, and accommodates a semiconductor wafer (not shown) as a substrate therein. The reaction vessel may be made of silicon carbide or alumina. A wafer support plate 217 as a support for supporting the semiconductor wafer is provided inside the reaction tube 203, and a gas introduction flange 209a and a gas introduction flange 209b as manifolds are provided at both ends of the reaction tube 203 in an airtight manner. A transfer chamber (not shown) is further connected to the gas introduction flange 209a via a gate valve 244 as a gate valve. Gas introduction lines 232a and 232b as supply pipes and exhaust lines 231a and 231b as exhaust pipes are connected to the gas introduction flange 209a and the gas introduction flange 209b, respectively. The gas introduction lines 232a and 232b are respectively provided with flow rate control means 241a and 241b for controlling the flow rate of the gas introduced into the reaction tube 203. The exhaust lines 231a and 231b are provided with pressure control means 248a and 248b for controlling the pressure in the reaction tube 203, respectively.

  An upper heater 207a and a lower heater 207b are provided above and below the reaction tube 203 as heating means, respectively, so that the inside of the reaction tube 203 is heated uniformly or with a predetermined temperature gradient. The upper heater 207a and the lower heater 207b are connected to temperature control means 247 for controlling the respective heater temperatures. A heat insulating material 208 is provided as a heat insulating member so as to cover the upper heater 207a, the lower heater 207b, and the reaction tube 203. The temperature in the reaction tube 203, the pressure in the reaction tube 203, and the flow rate of the gas supplied into the reaction tube 203 are set at predetermined temperatures by a temperature control means 247, pressure control means 248a and 248b, and flow rate control means 241a and 241b, respectively. , Pressure and flow rate are controlled. The temperature control unit 247, the pressure control units 248a and 248b, and the flow rate control units 241a and 241b are controlled by the main control unit 249.

  Of the above-described reaction tube 203, heaters 207a and 207b, gas introduction lines 232a and 232b, gas introduction flanges 209a and 209b, exhaust lines 231a and 231b, etc. A reaction furnace 201 to be processed is configured.

  Next, a method for processing a semiconductor wafer using the reaction furnace of the substrate processing apparatus described above as one step of the semiconductor device manufacturing process will be described.

  With the temperature in the reaction tube 203 maintained at the processing temperature by the heaters 207a and 207b, the gate valve 244 is opened, and the semiconductor wafer is loaded into the reaction tube 203 from the left in the drawing by the wafer transfer robot 250. And placed on the wafer support plate 217. In this example, two wafers (not shown) are placed on the wafer support plate 217, and the two wafers are processed simultaneously. Note that two wafers are simultaneously transferred into the reaction tube 203 in order to equalize the thermal history of the two wafers to be processed simultaneously. At the same time when the wafer is carried into the reaction tube 203, the temperature rise to the wafer processing temperature is started.

  After the wafer transfer robot 250 is retracted and the gate valve 244 is closed, the pressure in the reaction tube 203 is controlled by the pressure control means 248a and 248b so as to become the processing pressure (pressure stabilization), and the temperature in the reaction tube 203 is increased. Is controlled by temperature control means 247 so that the wafer temperature becomes the processing temperature (temperature stabilization). When the pressure in the reaction tube 203 is stabilized and the temperature of the wafer is stabilized, an inert gas is introduced into the reaction tube 203 from the gas introduction lines 232a and 232b and exhausted from the exhaust lines 231a and 231b. The inside is an inert gas atmosphere.

  After the pressure in the reaction tube 203 is stabilized at the processing pressure and the wafer temperature is stabilized at the processing temperature, a processing gas is introduced into the reaction tube 203 from the gas introduction lines 232a and 232b and exhausted from the exhaust lines 231a and 231b. As a result, the wafer is processed. At this time, in order to ensure the uniformity of processing, it is preferable that the processing gas flow alternately toward the diagonal. That is, for example, first, the processing gas flows from the gas introduction line 232a toward the exhaust line 231b in a direction substantially horizontal to the wafer surface, and then in the opposite direction, that is, from the gas introduction line 232b to the exhaust line 231a. It is preferable to flow in a direction substantially horizontal with respect to the surface of the wafer, and to change the direction of flow for each required time. Note that when the processing uniformity does not depend on the flow direction of the processing gas, the processing gas may flow in one direction. That is, for example, from the gas introduction line 232a toward the exhaust line 231b in a direction substantially horizontal to the wafer surface, or from the gas introduction line 232b toward the exhaust line 231a in a direction substantially horizontal to the wafer surface. You may make it flow.

The processing conditions for processing a substrate in the reaction furnace of the substrate processing apparatus of this embodiment are, for example, when forming a silicon film, a processing temperature of 614 ° C., a processing pressure of 0.13 Pa, and a gas type A case where film formation is performed with SiH ₄ , a gas flow rate of 60 sccm, and a time of 20 minutes is exemplified.

  When the processing of the wafer is completed, in order to remove the residual gas in the reaction tube 203, an inert gas is introduced into the reaction tube 203 from the gas introduction lines 232a and 232b and is exhausted from the exhaust lines 231a and 231b. The reaction tube is purged. The supply flow rate of the processing gas at the time of wafer processing and the supply flow rate of the inert gas before or after the wafer processing are controlled by the flow rate control means 241a and 241b.

  After purging in the reaction tube 203, the pressure in the reaction tube 203 is adjusted by the pressure control means 248a and 248b so as to become the wafer transfer pressure. After the pressure in the reaction tube 203 becomes the transfer pressure, the gate valve 244 is opened, and the wafer is transferred from the reaction tube 203 to the transfer chamber by the wafer transfer robot 250.

  The pressure control in the reaction tube 203 by the pressure control means 248a and 248b, the temperature control in the reaction tube 203 by the temperature control means 247, and the gas flow rate control into the reaction tube 203 by the flow rate control means 241a and 241b are as follows: This is performed by the main control unit 249 controlling each control means.

  By the way, in the method of processing a substrate using the reaction furnace 201 described above, the temperature in the reaction tube 203 is controlled by the temperature control means 247 so that the wafer temperature becomes the processing temperature. In this case, as shown in FIG. 2, first, the profile thermocouple 205 is used to control the outputs of the heaters 207a and 207b so that the internal temperature of the reaction tube 203 becomes a predetermined temperature. After the reaction tube internal temperature is stabilized, the heater temperature at that time is recorded (temperature profile acquisition), and when wafer processing is performed thereafter, based on the heater thermocouple 202 in each heater 207a, 207b using the acquired temperature profile. The method of temperature control is the same as before.

  However, in the conventional case, when the profile thermocouple 205 is installed between the quartz reaction tube 203 and a wafer support plate 217 as a support for supporting the wafer, the temperature in the furnace measured by the profile thermocouple 205 is measured. Is directly affected by radiant light scattering from the surface of the quartz reaction tube, so that the absolute value of the temperature monitor value of the profile thermocouple 205 deteriorates.

  Therefore, in the present embodiment, such a problem is solved by using two soaking plates 218 when acquiring the temperature profile. This will be described below.

  FIG. 2 is a schematic longitudinal sectional view of the flat reaction tube 203 taken along the tube axis. A reaction tube 203 is disposed between the two parallel plate heaters 207a and 207b. Two parallel flat wafer support plates 217 are provided in the reaction tube 203 in two upper and lower stages. A circular wafer hole 216 having a slightly larger diameter than the wafer is formed in the center of the wafer support plate 217, and a plurality of wafer support claws 219 are provided on the outer periphery of the bottom of the wafer hole 216. The two wafers fitted in the wafer hole 216 are supported by the plurality of support claws 219 and held on the wafer support plate 217. Here, a soaking plate 218 for shielding radiation light from the surface of the reaction tube 203 is fitted in the wafer hole 216 in place of the wafer. The soaking plate 218 is supported by a plurality of support claws 219 and held by the wafer support plate 217. A space 220 sandwiched between the two soaking plates 218 is formed in the furnace.

  The two soaking plates 218 can be carried into the reaction furnace 201 from one side (left side) of the reaction tube 203 by the wafer transfer robot 250 and can be taken out from the reaction furnace 201. In this case, it is preferable that the soaking plate 218 has substantially the same shape as the wafer. This is because if the soaking plate 218 has substantially the same shape as the wafer, the wafer carrying robot 250 can be used as the soaking plate carrying means. Further, the above-described space 220 can be easily formed by simply applying the process of supporting the two wafers to the wafer support plate 217 for supporting the wafer to the soaking plate 218 as it is. In particular, it is preferable to use a product wafer or a dummy wafer itself as the soaking plate 218.

  A plurality of heater thermocouples 202 as heater temperature measuring means for measuring the temperature in the heaters 207a and 207b are installed at predetermined positions in the two parallel plate heaters 207a and 207b. A plurality of profile thermocouples 205 as furnace temperature measuring means for monitoring and measuring the temperature of the wafer region inside the reaction tube are installed in a space 220 sandwiched between two upper and lower soaking plates 218.

  The plurality of profile thermocouples 205 are installed in a temperature probe 210 inserted from the other side (right side) of the reaction tube 203 to the vicinity of the center. By inserting this temperature probe 210 into the space 220, the profile thermocouple 205 is placed in the space. 220 is installed.

  The method of installing the profile thermocouple 205 will be described in detail with reference to FIG. 5 described above. From the gas introduction flange 209b provided on the other side of the reaction tube 203 on the side opposite to the gate valve 244, the center of the reaction tube 203 is provided. A temperature probe 210 (not shown) is inserted into the temperature probe 210, and a plurality of profile thermocouples 205 are installed at predetermined positions in the inserted temperature probe 210. The profile thermocouple 205 can be removed by removing the temperature probe 210 from the gas introduction flange 209b.

  Further, the main control unit 249 shown in FIG. 5 controls the wafer transfer robot 250 to take out the two soaking plates 218 from the reaction furnace 201 after measuring the in-furnace temperature, and remove the two soaking plates 218 into the reactor. The wafer is loaded into the reaction furnace 201 in a state of being taken out from the 201, the wafer is processed in the reaction furnace 201 using the result of the temperature measurement in the furnace, and the processed wafer is unloaded from the reaction furnace 201. To do.

  Returning to FIG. The two soaking plates 218 forming the above-described space 220 are installed in order to block the radiation light scattering factor due to the change in the unevenness of the quartz surface and to make the temperature in the space 220 uniform. Therefore, it is preferable that the soaking plate 218 is composed of a member having high thermal conductivity and low infrared transmittance. For example, it may be composed of either silicon or SiC. If the material of the soaking plate is silicon or SiC, these have low infrared transmittance and are not easily affected by radiation scattered light from the surface of the reaction tube 203, so the absolute value of the furnace temperature value described later is improved. Because it does.

3 and 4 show a block configuration of the temperature control system in which the absolute value of the furnace temperature value is improved.
The temperature control system includes a reaction tube 203 that accommodates a wafer, a heater 207 that heats the reaction tube 203, a heater thermocouple 202 that measures the temperature of the heater 207, and a space sandwiched between two soaking plates. A profile thermocouple 205 for measuring the temperature in the furnace and a temperature control means 247 for controlling the heater output are provided. The temperature control unit 247 includes a power control unit 246 that controls the heater output according to the power control amount, and a controller 245 that calculates the power control amount according to the thermocouple measurement value.

  When obtaining the temperature profile, as shown in FIG. 3, the profile thermocouple 205 monitors and measures the internal temperature of the reaction tube 203, that is, the wafer processing temperature. The temperature control means 247 controls the outputs of the heaters 207a and 207b so that the measured wafer processing temperature becomes a predetermined temperature. After the temperature inside the reaction tube 203 is stabilized, the heater temperature at that time is measured by the heater thermocouple 202. The controller 245 acquires a correlation between the wafer processing temperature and the heater temperature, that is, a temperature profile.

  At the time of wafer processing, the heater temperature is measured by the heater thermocouple 202 as shown in FIG. It can be seen from the temperature profile acquired by the controller 245 how many times the heater temperature should be set in order to set the internal temperature of the reaction tube 203 to a predetermined wafer processing temperature. The heater set temperature based on this temperature profile is compared with the heater measurement temperature, and the temperature of the heater 207 is controlled so that the furnace temperature becomes a predetermined wafer processing temperature.

Next, a method of film-forming a wafer using the reaction furnace 201 that performs wafer processing temperature calibration using the above-described soaking plate 218 will be described with reference to the process diagram of FIG.
First, the profile thermocouple 205 is installed between the wafer support plates 217 (step 101). The temperature probe 210 provided with the profile thermocouple 205 at the tip is inserted from an insertion hole provided on the surface of the gas introduction flange 209b opposite to the surface of the one gas introduction flange 209a that carries the wafer. The base end of the temperature probe 210 is fixed to the surface of the flange 209b and vacuum-sealed so that the profile thermocouple 205 is installed between the two wafer support plates 217.

After the profile thermocouple 205 is installed, the gate valve 244 provided on the surface of one gas introduction flange 209a for carrying the wafer is opened, and the two soaking plates 218 are carried into the furnace by the wafer carrying robot 250. The wafer support plate 217 is mounted on the soaking plate mounting portion, that is, the wafer mounting portion 215 (step 102). As a result of this placement, a space 220 sandwiched between two upper and lower soaking plates 218 is formed in the reaction furnace. A profile thermocouple 205 is installed in this space 220 (FIG. 2). After placing the soaking plate 218, the arm of the wafer transfer robot 250 is pulled out of the furnace, and the gate valve 244 is closed.
Note that the order of step 101 for installing the profile thermocouple 205 and step 102 for installing the soaking plate 218 may be reversed. That is, the two soaking plates 218 may be carried into the reaction furnace first, and the profile thermocouple 205 may be inserted into the space 220 sandwiched between the two soaking plates 218 later.

  After placing the heat equalizing plate 1218, as described with reference to FIG. 3, the output of the heater 1 is controlled by the temperature control means 247 so that the internal temperature of the reaction tube 203 becomes a predetermined wafer processing temperature. After the temperature inside the reaction tube is stabilized, a temperature profile is acquired using the profile thermocouple 205 (step 103).

  Although temperature changes occur in the furnace when the soaking plate 218 is carried in and out, the reaction furnace 201 according to the embodiment is a hot wall type furnace, and the heater is kept in a thermally stable state with a fixed temperature condition. Since the temperature and profile temperature are acquired, correction of the acquired profile temperature is unnecessary.

  After acquiring the temperature profile, the gate valve 244 provided on the surface of one gas introduction flange 209a is opened, and the two soaking plates 218 are carried out of the furnace by the wafer transfer robot 250 (step 104). After carrying out the soaking plate 218, the gate valve 244 is closed.

  After carrying out the soaking plate 218 out of the furnace, the temperature probe 210 attached to the surface of the other gas introduction flange 209b is extracted from the reaction furnace 201, and the profile thermocouple 205 is removed (step 105).

  After the profile thermocouple 205 is removed, the gate valve 244 is opened, and two wafers are loaded into the reaction furnace 201 by the wafer transfer robot 250 and placed on the wafer placement portion 215 of the wafer support plate 217 (step 106). ).

  After placing the wafer, as described with reference to FIG. 4, the temperature control unit 247 is used to control the temperature based on the heater thermocouple 202 in the heater 207 to stabilize the furnace temperature. And the furnace pressure is stabilized by the pressure control means 248a, 248b (step 107).

Then, the flow rate control means 241a and 241b exhaust the film while supplying a predetermined flow rate of reaction gas into the furnace and deposit it on the wafer (step 108). After film formation, the inside of the furnace is purged with an inert gas such as N ₂ gas (step 109). After purging, the gate valve 244 is opened, and the wafer carrying robot 250 unloads the wafer after film formation processing from the furnace (step 110).

  The film formation process in steps 101 to 110 described above is repeated, and the reaction by-products deposited on the reaction tube wall surface or the gas exhaust part are removed by performing wet cleaning (wet cleaning) and dry cleaning every predetermined cycle. .

According to the present embodiment, the space 220 sandwiched between the two soaking plates 218 is formed in the furnace, and the temperature in the furnace is monitored and measured by the profile thermocouple 205 in the space 220. The influence of the radiation light scattering factor on the temperature monitor value due to the unevenness of the quartz reaction tube surface can be mitigated.
Accordingly, since the absoluteity of the temperature profile value is improved, the wafer processing temperature calibration can be performed correctly. As a result, even if the unevenness of the quartz reaction tube surface increases due to damage due to dry cleaning and wet cleaning, it is possible to suppress a decrease in yield due to deterioration in film reproducibility. Further, since the replacement frequency of the quartz reaction tube 203 is reduced, the running cost can be reduced and the productivity can be improved.

  When the silicon film was formed according to the embodiment under the same film formation conditions as those of the conventional example that obtained the temperature characteristics of FIG. 9, the Seed film thickness conversion temperature in the graph was improved to about 614 ± 1 ° C. That is, the film formation result is less dependent on the amount of surface damage caused by cleaning the quartz reaction tube.

  In the above-described embodiment, the case where the two heat equalizing plates 218 are installed in parallel in the vertical direction has been described. However, in addition to the two upper and lower heat equalizing plates 218, two heat equalizing plates on both sides are provided. When a rectangular flat space is formed by further adding, it is possible to block radiation from the four sides of the reaction tube, so that the absolute value of the furnace temperature value can be further improved.

  Further, the semiconductor device manufacturing method of the present invention forms a thin film such as a metal film, a metal silicide film, an oxide film, a nitride film, or a silicon film doped with impurities on the semiconductor wafer surface, particularly in the semiconductor manufacturing process. It can be carried out using a semiconductor wafer processing apparatus such as a thermal CVD apparatus, a plasma CVD apparatus, an epitaxial growth apparatus for growing a single crystal layer on a semiconductor wafer, a dry etching apparatus for etching a thin film into a predetermined pattern, Among these, it is particularly useful when the processing is performed using a so-called hot wall type semiconductor wafer processing apparatus in which a semiconductor wafer is heated to form a film by heating a reaction tube of the processing apparatus from the outside.

It is process drawing of the film-forming process by embodiment explaining the manufacturing method of the semiconductor device of this invention. It is a schematic side longitudinal cross-sectional view of the reaction furnace of the substrate processing apparatus for enforcing the manufacturing method of the semiconductor device of this invention. It is a function explanatory view of the temperature control system at the time of temperature profile acquisition by an embodiment. It is function explanatory drawing of the temperature control system at the time of the wafer process by embodiment. It is a principal part schematic longitudinal cross-sectional view of the reaction furnace of the substrate processing apparatus by embodiment. It is a longitudinal cross-sectional view of the reaction furnace of the substrate processing apparatus by a prior art example. It is a plane sectional view of the reaction furnace of the substrate processing apparatus by a prior art example. It is a principal part schematic longitudinal cross-sectional view of the reaction furnace of the substrate processing apparatus by a prior art example. It is a temperature characteristic figure which shows transition of the profile temperature and seed film thickness conversion temperature by repeating cleaning of the reactor by a prior art example.

Explanation of symbols

201 Reaction furnace 202 Heater thermocouple 203 Reaction tube 205 Profile thermocouple 207a Upper heater 207b Lower heater 210 Temperature probe 215 Wafer mounting part (soaking plate mounting part)
217 Wafer support plate 218 Soaking plate 220 Space

Claims (1)

Carrying at least two soaking plates into the reactor;
Measuring the temperature in the furnace in a space sandwiched between the two soaking plates,
After the furnace temperature measuring step, the step of taking out the two soaking plates from the reactor,
Carrying the substrate into the reaction furnace in a state in which the soaking plate is removed from the reaction furnace;
Processing the substrate using the result of the temperature measurement in the reactor;
Unloading the processed substrate from the reactor; and
A method for manufacturing a semiconductor device, comprising:

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