JP2006121099A - Semiconductor process control device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor process control device, which realizes a stable semiconductor process, by a method wherein a cause of variation in a device structure is detected before the device is manufactured in pilot modeling. <P>SOLUTION: The semiconductor process control device is composed of a pressure gauge 2 which measures the pressure inside a CR where an oxidation oven 1 is installed, a thermal treatment time variation calculator 3 which gives an oxidation time variation which restrains a device structure variation caused by the pressure measured with the pressure gauge 2 corresponding to process conditions, and a controller 4 which controls a semiconductor manufacturing process adding the above calculated thermal treatment time variation to a thermal treatment time after a temperature rise time in a thermal treatment process in the oxidation oven 1. The thermal treatment process is a thermal oxidation, when the thermal oxidation of the oxidation time of T minutes is performed, and when the measured pressure is x% of the mean rate of a preset pressure, the thermal treatment time variation ΔT is ΔT=T ä1-(x/100)<SP>2</SP>}/(x/100)<SP>2</SP>. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a semiconductor process control apparatus and control method, and more particularly to a semiconductor device structure that realizes a stable semiconductor device structure in a semiconductor process.

  In recent years, as the integration density of semiconductor integrated circuits has increased, minute variations such as oxide film thickness and CVD film thickness that constitute a fine semiconductor device have caused an illegal operation of the circuit, thereby reducing the yield of products.

  In the conventional semiconductor manufacturing apparatus, the film thickness of the thermal oxide film or the atmospheric pressure CVD film varies due to the influence of the atmospheric pressure, and the instability of the semiconductor circuit characteristics is caused by the variation of the semiconductor device structure. Hereinafter, the prior art and its problems will be described by taking the case of a thermal oxidation furnace as an example.

  The thickness of the thermal oxide film is controlled by the oxidizing gas pressure, the oxidizing temperature, the oxidizing time, etc. in the oxidizing atmosphere, but the oxidizing gas pressure is affected by the atmospheric pressure of the environment where the thermal oxidation furnace is placed. That is, when the atmospheric pressure is high, the oxidizing gas pressure increases, and the density of the oxidizing agent increases, so that the oxidation rate increases. On the contrary, when the atmospheric pressure is low, the oxidizing gas pressure becomes low and the oxidation rate becomes slow. For this reason, even if the oxidation is performed while keeping the process control parameter at the time of oxidation constant in the thermal oxidation furnace, the fluctuation of the oxidation rate due to the fluctuation of the atmospheric pressure occurs and the thickness of the oxide film varies.

  FIG. 6 is a diagram for explaining a conventional film thickness control process. In order to suppress variations in film thickness, in a quality check (hereinafter referred to as QC) performed at a predetermined time interval, oxidation is first performed (61) to produce a monitor wafer. After this oxidation, the oxide film thickness on the monitor wafer is measured (62). Then, based on the measured film thickness, a subsequent process recipe (process condition table) is corrected so as to suppress the film thickness variation value, and a process parameter correction value is calculated (63). The corrected process recipe is input to an oxidation furnace controller that performs process control of the oxidation furnace, and oxidation is performed again under process conditions that suppress variations in film thickness (61).

  However, in the conventional film thickness control, since the structure fluctuation is observed and corrected after the oxidation treatment is performed once, the correction is made after the actual process fluctuation occurs. A stable device structure could not be obtained. On the other hand, in recent years, with the progress of miniaturization of semiconductor devices, the influence of minute fluctuations in the device structure on device characteristics is increasing.

  On the other hand, in recent years, the use of Si layers epitaxially grown on Si substrates has been expanded. In the case of a fine Si device, control of the film thickness of the epitaxial layer is important for structural control. Since a dangerous gas such as a Si compound is used in a CVD process such as an epitaxial process, the CVD apparatus is designed as a non-open system. However, in the case of atmospheric pressure CVD, it is not in direct contact with the atmospheric pressure as in the case of an open system, but the exhaust side is in direct contact with the outside through an exhaust gas detoxification device. For this reason, in atmospheric pressure CVD, when the atmospheric pressure changes, the atmospheric pressure in the chamber changes under the influence of this change, and the deposited film thickness fluctuates even if other conditions are the same. Therefore, the same problem as in the case of forming the thermal oxide film occurs.

  On the other hand, semiconductor integrated circuit development bases and developed integrated circuit production bases are often located in regions with different weather conditions, and in recent years, production bases are often located outside Japan. . Therefore, even if film formation is performed under the same conditions as the film formation control conditions established at the development site, the film thickness value due to oxide film formation or atmospheric pressure CVD film formation is uneven depending on the region because the atmospheric pressure value of the environment is different. It was. For this reason, in order to obtain the same device structure, different process control parameter corrections are required in each region, which hinders stable mass production start-up at each production base.

  In view of the fact that atmospheric pressure affects film thickness variation as described above, it is necessary to manage the film thickness closer to the cause than with QC data in order to further improve the process.

  As described above, in the conventional semiconductor process control, in order to suppress the film thickness variation, the QC management performed at a predetermined time interval knows and corrects the structural variation after the manufacturing process. Therefore, a sufficiently stable device structure could not be obtained according to the QC management time interval. On the other hand, in recent years, with the progress of miniaturization of semiconductor devices, the influence of minute fluctuations in the device structure on device characteristics is increasing.

  On the other hand, semiconductor integrated circuit development bases and production bases are often located in regions with different weather conditions. For this reason, even if film formation is performed under the same conditions as the film formation control conditions set at the development site, the film thickness value due to the formation of an oxide film or atmospheric pressure CVD film is uneven depending on the region because the atmospheric pressure value differs. It becomes.

  Thus, in view of the fact that atmospheric pressure affects film thickness variation, it is necessary to perform film thickness management closer to the cause than with QC data.

Conventionally, techniques for measuring changes in atmospheric pressure and controlling film thickness have been developed (see, for example, Patent Document 1 and Patent Document 2). However, further improvements are desired.
Japanese Patent Laid-Open No. 5-32500 JP-A-7-74166

  An object of the present invention is to provide a semiconductor process control apparatus and a control method for detecting a cause of device structure variation before performing a process and realizing a stable semiconductor process.

The aspect of the semiconductor process control apparatus of the present invention is a means for measuring a pressure value in a semiconductor manufacturing apparatus for manufacturing a semiconductor device by heat treatment in an atmosphere affected by atmospheric pressure or in an installation environment of the apparatus, Means for calculating a heat treatment time fluctuation value for suppressing device structure fluctuations due to fluctuations in the atmospheric pressure value, and the calculated heat treatment time fluctuation value from the initial temperature to a predetermined heat treatment time preset in the semiconductor manufacturing apparatus Means for correcting the heat treatment time by adding after the elapse of time for raising the temperature inside the semiconductor manufacturing apparatus to the heat treatment temperature, and the heat treatment is thermal oxidation, and when performing thermal oxidation for an oxidation time of T minutes, When the measured atmospheric pressure value is x% of the average value of preset atmospheric pressure values, the heat treatment time variation value ΔT is ΔT = T {1− (x / 100) ² } / (x / 100) ²
It is characterized by being.

In the semiconductor process control method according to the present invention, when a semiconductor device is manufactured using a semiconductor manufacturing apparatus having a function of performing heat treatment in an atmosphere affected by atmospheric pressure, the semiconductor process control method is installed in the semiconductor manufacturing apparatus or in the installation environment of the apparatus. Time for measuring the atmospheric pressure value and raising the temperature inside the semiconductor manufacturing apparatus from the initial temperature to the predetermined heat treatment temperature during the heat treatment time preset in the semiconductor manufacturing apparatus according to the measured atmospheric pressure value. The heat treatment is thermal oxidation, and when the thermal oxidation is performed for an oxidation time of T minutes, the measured atmospheric pressure value is x% of an average value of preset atmospheric pressure values. The variation value ΔT of the heat treatment time is ΔT = T {1− (x / 100) ² } / (x / 100) ²
It is characterized by being.

The semiconductor process control system of the present invention includes a semiconductor manufacturing apparatus for manufacturing a semiconductor device by heat treatment in an atmosphere affected by atmospheric pressure, means for measuring the atmospheric pressure value in the apparatus or the installation environment of the apparatus, and the measurement Means for calculating a heat treatment time fluctuation value for suppressing device structure fluctuations due to fluctuations in the atmospheric pressure value, and the calculated heat treatment time fluctuation value from the initial temperature at a heat treatment time preset in the semiconductor manufacturing apparatus. Means for correcting the heat treatment time by adding after the elapse of time for raising the temperature inside the semiconductor manufacturing apparatus to a predetermined heat treatment temperature, the heat treatment is thermal oxidation, and thermal oxidation is performed for an oxidation time of T minutes. In this case, when the measured atmospheric pressure value is x% of an average value of preset atmospheric pressure values, the heat treatment time variation value ΔT is ΔT = T {1− (x / 100) ² } / (x / 100) ²
It is characterized by being.

  ΔT is an equation obtained for an ideal case in which film formation is performed according to the supply rate-limiting due to the diffusion of the oxidant in the thermal oxide film. When the thermal oxidation condition deviates from the ideal supply rate control and the equation of ΔT does not hold, ΔT obtained corresponding to each thermal oxidation condition is given.

  The heat treatment time fluctuation value is added immediately after the inside of the oxidation furnace is heated from the initial temperature to a predetermined oxidation temperature and stabilized at the oxidation temperature.

  The operation of the present invention will be described with reference to FIG. When heat treatment is performed in the semiconductor manufacturing apparatus, the atmospheric pressure value in the manufacturing apparatus or the installation environment of the manufacturing apparatus is affected by the atmospheric pressure value. The atmospheric pressure value measuring unit 51 measures the atmospheric pressure value in the manufacturing apparatus or its installation environment affected by the atmospheric pressure value of this environment, and outputs the measured value to the heat treatment time fluctuation value calculating unit 52. The heat treatment time fluctuation value calculation unit 52 calculates a heat treatment time fluctuation value that suppresses device structure fluctuations based on the input atmospheric pressure value in the manufacturing apparatus or its installation environment, and outputs the heat treatment time fluctuation value to the control unit 53. The control unit 53 controls the semiconductor process by adding a heat treatment time fluctuation value to the heat treatment time after the temperature rising time in the device during the heat treatment of the semiconductor manufacturing apparatus.

  Control for changing the pressure value of each semiconductor manufacturing apparatus is complicated and involves instability. This is because when a gas system with some atmospheric pressure control is used to control the atmospheric pressure around the wafer, a by-product substance on the process accumulates in the pipe, and it is difficult to control accurately due to this influence.

  Therefore, a heat treatment time capable of stable and fine control is used as a correction process control parameter for reducing device structure variations. By performing the heat treatment for the heat treatment time to which the corrected time is added, the film thickness fluctuation affected by the atmospheric pressure value can be suppressed without creating a prototype. Further, the control variation of the set value of the time is extremely small, and the correction can be performed with high accuracy compared with the case of correcting the pressure and temperature. Further, by adding this correction time after the time of raising the temperature to a predetermined heat treatment temperature, stable process time control can be performed.

  According to the semiconductor process control apparatus and the control method of the present invention, the cause of device structure fluctuation is detected by measuring the atmospheric pressure value affected by the environment before trial manufacture, and based on the detected atmospheric pressure fluctuation value. By adding the heat treatment time fluctuation value after the temperature rise time in the semiconductor manufacturing apparatus and performing the heat treatment, the film thickness fluctuation affected by the atmospheric pressure value can be suppressed without creating a prototype. Stable process time control without delay is possible.

  In addition, since a heat treatment time that can be controlled with high accuracy is used as a correction parameter for semiconductor process control, the sensitivity is low with respect to parameter variations and control is easy.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram showing an overall configuration of a semiconductor process control apparatus according to a first embodiment of the present invention. As shown in FIG. 1, this semiconductor process control apparatus controls an oxidation furnace 1 designed as an open system by a controller 5, and includes an atmospheric pressure value measurement unit 2, an oxidation time fluctuation value calculation unit 3, and a control unit. 4 are installed in a clean room (hereinafter referred to as CR).

  The atmospheric pressure value measuring unit 2 is a part that measures the atmospheric pressure value of the environment, and is substituted by the part that measures the atmospheric pressure value in the CR in the CR management mechanism. Since the oxidation furnace 1 is in the CR, and the atmospheric pressure in the CR is controlled by the differential pressure from the outside, the atmospheric pressure in the CR is affected by the atmospheric pressure. Therefore, the atmospheric pressure value measuring unit 2 detects the cause of the device structure variation affected by the environmental atmospheric pressure value by measuring the atmospheric pressure value of the in-CR detection unit 6.

  The oxidation time fluctuation value calculation unit 3 is a part that calculates an oxidation time fluctuation value based on the atmospheric pressure in the CR, which is a measurement value of the atmospheric pressure value measurement unit 2, and suppresses fluctuations in the oxide film thickness due to fluctuations in the atmospheric pressure value. Correct correction values are given according to the oxidation conditions. For example, when thermal oxidation is performed for an oxidation time of T minutes, when the atmospheric pressure value measured by the atmospheric pressure value measurement unit 2 is x% of the preset atmospheric pressure value, the oxidation time fluctuation value ΔT is expressed by the following formula (1 )

ΔT = T {(1− (x / 100) ² )} / (x / 100) ² (1)
Expression (1) is an expression obtained for an ideal case in which film formation is performed according to the supply rate-limiting due to the diffusion of the oxidizing agent in the thermal oxide film. Therefore, when the thermal oxidation conditions deviate from the ideal supply rate control and the equation (1) does not hold, for example, when a portion not dependent on the supply rate control is included such as in the case of initial oxidation of dry oxidation, Without being limited, a variation value ΔT corresponding to each thermal oxidation condition is given.

  The control unit 4 controls the controller 5 by adding the oxidation time variation value given by the oxidation time variation value calculation unit 3 to the oxidation time preset in the control unit 4, and by this control, the oxidation furnace 1 is controlled. The manufacturing process is performed in the oxidation time varied so as to suppress the oxide film thickness variation.

  Next, an example of time control of temperature change in the furnace in the case of performing thermal oxidation is shown in FIG. 2 (a) shows the case of time control without adding the oxidation time fluctuation value, FIG. 2 (b) shows the case of time control with the oxidation time fluctuation value added, the horizontal axis is time, and the vertical axis is the furnace temperature. It is. 21 is a holding time for inserting the wafer and stabilizing the inside of the furnace at the initial temperature, 22 is a time for raising the temperature of the wafer from the initial temperature to a predetermined oxidation temperature, and 23 is an oxidizing agent at the predetermined oxidation temperature. The time to be supplied to the wafer, 24 is a time when other processing such as inert annealing is applied if necessary, and 25 is a time for lowering the temperature to around room temperature.

  In the control for variation reduction used in this embodiment, as shown in FIG. 2B, the oxidation time fluctuation value ΔT calculated by the expression (1) by the oxidation time fluctuation value calculation unit 3 is set to a predetermined 23 times. The oxidation time is 26.

  The operation of the semiconductor process control apparatus according to the above embodiment will be described. When thermal oxidation is performed in the oxidation furnace 1, the atmospheric pressure in the CR in which the oxidation furnace 1 is installed is affected by the atmospheric pressure value. Although the oxidation furnace 1 is in the CR and the atmospheric pressure in the CR is controlled, the atmospheric pressure in the CR is affected by the atmospheric pressure value because it is controlled by the differential pressure from the outside. The pressure in the oxidation furnace 1 is affected not only by the pressure in the CR but also by the pressure reduction value on the exhaust side, but the pressure reduction value on the exhaust side is very weak, and the influence of the fluctuation of the exhaust pressure is the fluctuation of the atmospheric pressure value of the environment, That is, it is extremely small compared to the fluctuation of atmospheric pressure. For this reason, the oxidation rate varies under the influence of atmospheric pressure. Therefore, the atmospheric pressure value measuring unit 2 measures the atmospheric pressure in the CR affected by the atmospheric pressure value of this environment, which is the cause of the oxide film thickness fluctuation, and outputs the measured value to the oxidation time fluctuation value calculating unit 3.

  The oxidation time fluctuation value calculation unit 3 calculates an oxidation time fluctuation value that suppresses fluctuations in the device structure based on the input atmospheric pressure value in the CR, using Equation (1), and outputs the calculated value to the control unit 4. Thereby, the oxidation time fluctuation value that suppresses the film thickness fluctuation caused by the pressure fluctuation value can be predicted without going through the process.

  In the thermal oxidation in the oxidation furnace 1, the control unit 4 controls the controller 5 to perform the manufacturing process by adding an oxidation time fluctuation value to the oxidation time after passing through the temperature rising time in the furnace. Based on the signal input from the control unit 4, the controller 5 performs a manufacturing process step in the oxidation furnace 1 that suppresses structural variations without delay.

  As shown in FIG. 2 (a), the wafer that has been entered at a temperature equal to or lower than the oxidation temperature is oxidized by switching the gas to an oxidizing atmosphere through a temperature rising step 22 and a certain temperature stabilization time (23). . Thereafter, through an annealing process 24, a temperature lowering step 25 and a furnace are performed, and the oxidation process is completed. Thus, in order to avoid the formation of a natural oxide film formed in the loading / unloading furnace, the loading / unloading furnace temperature is lowered as shown in steps 21, 22, and 25.

  Of the process control by the oxidation time corrected by the oxidation time fluctuation value, the process time component corresponding to the process in which the oxide film is mainly stably formed is corrected (26). When the oxidant is supplied even during the temperature rise and fall, the state in the apparatus during the temperature rise and fall is not stable and the control is unstable. Therefore, the time control for obtaining a predetermined film thickness is to add the oxidation time fluctuation value ΔT to the time T corresponding to 23 which is a process of mainly forming the oxide film as shown in FIG. The corrected oxidation time is T + ΔT. By using the process shown in 23 as an object of control, stable process time control that suppresses fluctuations in film thickness due to variations in atmospheric pressure can be obtained.

  Further, as described above, the thickness of the thermal oxide film can be controlled by the oxidizing gas pressure in the oxidizing atmosphere, the oxidation temperature, the oxidation time, etc., but the non-uniformity of the oxidation temperature depends on the form of each device. It is different and depends on individual conditions. Therefore, it is difficult to increase the uniformity of the temperature distribution within the apparatus and the temperature distribution between wafers and within the wafer in order to reduce the variation in oxidation temperature.

  On the other hand, the gas pressure variation depends on the atmospheric pressure in the case of a normal pressure device. Here, the atmospheric pressure does not depend on individual devices, and is an element common to the devices installed in the same environment, and the commonality of fluctuations in internal pressure among the devices is high. Therefore, as shown in the present embodiment, the product variation can be efficiently removed by detecting the atmospheric pressure value and controlling to cancel the variation value of the device structure.

FIG. 3 is a simulation comparison of the effect of minute fluctuations in atmospheric pressure on the oxide film thickness by varying the oxidation temperature, oxidation gas pressure, and oxidation time, which are process parameters. An oxide film is formed at 950 ° C. in a dry O ₂ atmosphere, and the temperature rise rate is 100 ° C./min and the oxidation time is 9.5 minutes by FTP (Fast Thermal process). The sensitivity analysis simulation was performed by giving the following parameter variation, and the vertical axis represents the film thickness.

Oxidation temperature 3σ = 1 ° C., O ₂ gas pressure 3σ = 20 mb, oxidation time 3σ = 1 second In FIG. 3, 31 is a reference oxide film thickness formed with preset process parameters, and 32 is a variation in oxidation temperature. The oxide film thickness when the gas pressure variation is given, and the oxide film thickness when the oxidation time variation is given are shown. It can be seen that the sensitivity of the film thickness to the gas pressure variation is high as well as the temperature variation, and a variation of about ± 0.2 nm at 3σ results from the gas pressure variation. In the case of Si MOSFET, this fluctuation value causes a threshold voltage fluctuation of about ± 50 mV, which causes a decrease in yield in device manufacturing. On the other hand, since the film thickness variation is small when the oxidation time variation is given, the oxidation time can be used as a correction parameter for process control, so that highly accurate correction can be performed.

  As described above, since the process parameter is changed when the pressure variation monitored by the pressure value measuring unit 2 is detected, the process control for suppressing the film thickness variation can be performed without time delay, and the production yield is improved. To do. In addition, it is possible to reduce the work load for performing a minute correction using a monitor wafer as in the conventional process control.

  In addition, in the process control by the oxidation time corrected by the oxidation time fluctuation value, the oxidation process in which the oxide film thickness does not vary by correcting the process time component corresponding to the process in which the oxide film is mainly stably formed is corrected. Can be realized.

  Further, since the variation in time control is small, the influence on the oxide film thickness is small compared to the variation in temperature and gas pressure, and stable and fine process control is possible by using the oxidation time as a correction parameter.

(Second Embodiment)
FIG. 4 is a diagram showing an overall configuration of a semiconductor process control apparatus according to the second embodiment of the present invention. As shown in FIG. 4, this semiconductor process control apparatus controls a normal pressure epitaxial growth CVD apparatus 41 designed as a non-open system by a controller 45, and includes an atmospheric pressure value measurement unit 42, a deposition time fluctuation value calculation unit 43, The controller 44 is configured. This atmospheric pressure epitaxial growth CVD apparatus 41 is a non-open system, and the outside world is not in direct contact with the inside of the apparatus 41, but through an exhaust gas detoxification apparatus 46 provided for exhausting the gas introduced at the time of CVD. Indirect contact with the outside world.

  The atmospheric pressure value measurement unit 42 is a part that measures the installation environment of the CVD apparatus 41 affected by the atmospheric pressure of the environment that is the cause of the device structure fluctuation, that is, the atmospheric pressure value in the CVD chamber.

The deposition time fluctuation value calculation unit 43 is a part that provides a deposition time fluctuation value that suppresses fluctuations in the deposited film thickness due to fluctuations in the atmospheric pressure value obtained by the atmospheric pressure value measurement unit 42 according to the process conditions. For example, when atmospheric pressure epitaxial growth is performed using 80% N ₂ as a dilution gas and a silane chloride-based gas, the atmospheric pressure value measured by the atmospheric pressure measurement unit 42 is preset when performing epitaxial growth for T minutes. When the atmospheric pressure value is x%, the deposition time fluctuation value is given by the following equation (2).

ΔT = T {1− (x / 100)} / (x / 100) (2)
Expression (2) is an expression obtained for an ideal case in which film formation is performed in accordance with a supply rate in proportion to the reaction gas concentration on the film surface after deposition in dilution CVD. Accordingly, when the CVD conditions are not ideal supply rate control and the formula (2) does not hold, such as the reaction rate-determined film formation conditions when the concentration of the reaction gas is higher, the formula (2) is not limited. ΔT obtained corresponding to each CVD condition is given.

  The control unit 44 controls the controller 45 by adding the deposition time variation value given by the deposition time variation value calculating unit 43 to the deposition time preset in the control unit 44, and is controlled by the control unit 44. Thus, the manufacturing process is performed in the deposition time varied so as to suppress the film thickness variation in the atmospheric pressure CVD apparatus 41.

  The time control in the atmospheric pressure epitaxial growth CVD apparatus 41 can be explained according to the case of the thermal oxide film formation of FIG. 21 is a holding time for stabilizing the state in the chamber after inserting the wafer into the chamber, 22 is a temperature raising time for raising the temperature in the apparatus up to a predetermined temperature, and 24 is a furnace at a predetermined temperature. 23 corresponds to the reaction time for introducing the silane chloride-based reaction gas into the chamber, and 25 corresponds to the time for lowering the temperature to around room temperature.

  In the present embodiment, the predetermined time 23 for introducing the reaction gas into the chamber is corrected using the deposition time fluctuation value given by the deposition time fluctuation value calculation unit 43, and the process is performed in 26 of FIG. The CVD process is performed using the corresponding corrected reaction time.

  The operation of the semiconductor process control apparatus according to the above embodiment will be described. When CVD is performed in the atmospheric pressure epitaxial growth CVD apparatus 41, the CVD apparatus 41 is indirectly in contact with the outside through the exhaust gas detoxification apparatus 46, so the internal pressure in the CVD apparatus 41 is affected by the atmospheric pressure value of the environment. The atmospheric pressure value measuring unit 42 measures the internal pressure affected by the atmospheric pressure value which is the cause of the CVD film thickness fluctuation, and outputs the measured value to the deposition time fluctuation value calculating unit 43.

  The deposition time fluctuation value calculation unit 43 calculates a deposition time fluctuation value that suppresses the fluctuation of the device structure based on the input atmospheric pressure value by the equation (2), and outputs it to the control unit 44. Thereby, the deposition time fluctuation value that suppresses the CVD film thickness fluctuation caused by the value of the atmospheric pressure fluctuation can be predicted without going through trial manufacture.

  In the CVD of the atmospheric pressure epitaxial growth CVD apparatus 41, the control unit 44 controls the controller 45 to perform a manufacturing process by adding a deposition time variation value to the deposition time after the temperature rising time in the chamber. The controller 45 performs, in the CVD apparatus 41, a manufacturing process step in which structural variations are suppressed without time delay based on the signal input from the control unit 44.

  Of the process control based on the time corrected by the correction value obtained by the deposition time fluctuation value calculation unit 43, this is realized by correcting the process time component corresponding to the process in which the CVD film is mainly formed stably. A CVD process in which there is no variation in film thickness can be realized.

  As described above, by using the atmospheric pressure value measurement unit 42, it is possible to directly obtain and control the cause of variation compared to the conventional indirect control method using a monitor wafer, and to control the film with higher accuracy. Thickness variation can be suppressed. In addition, since the deposition time fluctuation value calculation unit 43 can immediately obtain the deposition time correction value in conjunction with the cause variation, the deposition time correction can be performed without a time delay. Furthermore, the control unit 44 can reduce the work load for performing a minute correction under process conditions using a conventional monitor wafer.

  In general, low-pressure CVD is performed in many cases where high-precision film thickness control is required. However, the semiconductor process control device according to the present embodiment allows the atmospheric pressure CVD, which is a device having a simpler configuration than the case of low-pressure. The apparatus can also be used when highly accurate film thickness control is required. Accordingly, since it is not necessary to perform the film formation process under reduced pressure, the process time can be shortened, and an integrated circuit having a stable structure can be manufactured at a lower cost than in the case of reducing pressure.

  In the present embodiment, the case where the present invention is applied to an atmospheric pressure epitaxial growth CVD apparatus has been described. However, any atmospheric pressure CVD apparatus that is affected by atmospheric pressure may be used.

  In the first and second embodiments, the case where the manufacturing process time fluctuation values are given by the equations (1) and (2) is shown. However, when the reaction property changes in the film formation process, the reaction property is changed. It is also possible to select the formula (1) and the formula (2) according to the above and obtain the manufacturing processing time fluctuation value.

  In addition, it is not limited to atmospheric pressure CVD equipment and thermal oxidation furnaces, and it can be applied to diffusion equipment etc. by giving a formula that gives the heat treatment time fluctuation value based on experience, etc., if it is a heat treatment equipment affected by atmospheric pressure It is.

  It is also possible to provide a manufacturing process time fluctuation value that suppresses device structure fluctuation due to fluctuations in the atmospheric pressure value by a numerical table depending on the process conditions. In this case, when the nature of the reaction is unknown during the film formation process, the device structure fluctuation due to fluctuations in the atmospheric pressure value is obtained experimentally, and when the experimental result data is stored and used, the film thickness fluctuation due to fluctuations in atmospheric pressure value It is possible to obtain a process time correction value that suppresses.

(Third embodiment)
The third embodiment relates to development of a semiconductor memory manufacturing process and transfer of manufacturing technology to a manufacturing base. That is, the semiconductor memory is first manufactured at the development base, the technology is transferred to the manufacturing base by the manufacturing process developed at this time, and the manufacturing is similarly performed at the manufacturing base. Hereinafter, a case where a gate oxide film of a MOSFET forming a semiconductor memory is formed will be described as an example.

  First, a CR internal pressure value that is a reference at a development site is determined, and a MOSFET gate oxide film thickness value is determined based on this atmospheric pressure value. (A) Pressure value measuring unit that measures the pressure fluctuation value in the CR at the development site in the oxidation furnace that performs gate oxidation, and (B) The oxidation time fluctuation value that calculates the fluctuation value of the gate oxide film thickness value caused by this fluctuation value A calculation unit and a control unit that realizes an oxidation process control in which oxidation is performed using the oxidation time corrected by the correction values obtained in (C) and (B) in the oxidation furnace are installed. These (A) to (C) correspond to the atmospheric pressure value measurement unit 2, the oxidation time fluctuation value calculation unit 3, and the control unit 4 in the first embodiment.

  When the development base develops a semiconductor memory manufacturing process using (A) to (C) and performs gate oxidation using the oxidation time corrected by the correction value calculated in (B), The process parameters are set so that the magnitude of fluctuation of other device structure parameters due to correction does not give instability to the circuit characteristics.

  After the development of the semiconductor process in this way, when the manufacturing technology is transferred to the manufacturing base, a part for obtaining the (A ′) CR internal pressure value of the manufacturing base is newly provided at the manufacturing base. In addition, using the same (B) and (C) used at the development site, the manufacturing technology is launched. In the start-up of this manufacturing technology, it is not necessary to obtain the optimal control parameters through trial and error as in the past. If only the reference value in the CR of the manufacturing base is obtained by (A '), it is as early as the development base. It is possible to start manufacturing.

  As a result, the variation in the integrated circuit characteristics due to the difference in the device structure based on the difference in the atmospheric pressure values in a plurality of regions can be suppressed, and the transfer of the manufacturing process developed at the development base to the manufacturing base can be realized at an early stage.

  Note that the present invention can be applied to any process that performs heat treatment such as CVD as well as the gate oxide film formation process.

The figure which shows the whole structure of the oxidation furnace control apparatus which concerns on 1st Embodiment of this invention. The figure which shows the furnace temperature in the same embodiment. The figure which shows the influence which the dispersion | variation in a process parameter has on a film thickness. The figure which shows the whole structure of the atmospheric pressure epitaxial growth CVD control apparatus which concerns on 2nd Embodiment of this invention. The figure explaining the main point of this invention. The figure explaining the process of the conventional film thickness control.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Oxidation furnace 2,42 ... Barometric pressure value measurement part, 3 ... Oxidation time fluctuation value calculation part, 4,44 ... Control part, 5,45 ... Controller, 31 ... Standard oxide film thickness, 32 ... Oxidation temperature variation 33 ... Oxide thickness due to gas pressure variation, 34 ... Oxide thickness due to variation in oxidation time, 41 ... Normal pressure epitaxial growth CVD apparatus, 43 ... Deposition time fluctuation value calculation unit, 46 ... Detoxification of exhaust gas apparatus.

Claims (3)

Means for measuring a pressure value in a semiconductor manufacturing apparatus for manufacturing a semiconductor device by heat treatment in an atmosphere affected by atmospheric pressure or in an installation environment of the apparatus;
Means for calculating a heat treatment time fluctuation value for suppressing device structure fluctuation due to fluctuation of the measured atmospheric pressure value;
The calculated heat treatment time fluctuation value is added to the heat treatment time preset in the semiconductor manufacturing apparatus after the elapse of time for raising the temperature in the semiconductor manufacturing apparatus from the initial temperature to a predetermined heat treatment temperature, thereby correcting the heat treatment time. And means for
When the thermal treatment is thermal oxidation and thermal oxidation is performed for an oxidation time of T minutes, when the measured atmospheric pressure value is x% of an average value of preset atmospheric pressure values, the thermal treatment time variation value ΔT is ΔT = T {1- (x / 100) ² } / (x / 100) ²
A semiconductor process control device characterized by the above. When manufacturing a semiconductor device using a semiconductor manufacturing apparatus having a function of performing heat treatment in an atmosphere affected by atmospheric pressure,
The atmospheric pressure value in the semiconductor manufacturing apparatus or in the installation environment of the apparatus is measured, and the heat treatment time fluctuation value is changed from the initial temperature to a predetermined heat treatment time set in advance in the semiconductor manufacturing apparatus according to the measured atmospheric pressure value. Add and correct after the elapse of time to raise the temperature in the semiconductor manufacturing apparatus to the temperature,
The thermal treatment is thermal oxidation, and when thermal oxidation is performed for an oxidation time of T minutes, when the measured atmospheric pressure value is x% of an average value of preset atmospheric pressure values, the variation value ΔT of the thermal treatment time. ΔT = T {1- (x / 100) ² } / (x / 100) ²
A method for controlling a semiconductor process. A semiconductor manufacturing apparatus for manufacturing a semiconductor device by heat treatment in an atmosphere affected by atmospheric pressure;
Means for measuring the atmospheric pressure value in the apparatus or in the installation environment of the apparatus;
Means for calculating a heat treatment time fluctuation value for suppressing device structure fluctuation due to fluctuation of the measured atmospheric pressure value;
The calculated heat treatment time fluctuation value is added to the heat treatment time preset in the semiconductor manufacturing apparatus after the elapse of time for raising the temperature in the semiconductor manufacturing apparatus from the initial temperature to a predetermined heat treatment temperature, thereby correcting the heat treatment time. And means for
When the thermal treatment is thermal oxidation and thermal oxidation is performed for an oxidation time of T minutes, when the measured atmospheric pressure value is x% of an average value of preset atmospheric pressure values, the thermal treatment time variation value ΔT is ΔT = T {1- (x / 100) ² } / (x / 100) ²
A semiconductor process control system.

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