JPH11186249A - Semiconductor process control device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a stable semiconductor process, by a method wherein a cause of variation in a device structure is detected before a device is manufactured before pilot modeling. SOLUTION: A semiconductor process control device is composed of a pressure gauge 2 which measures the pressure inside a CR where an oxidation oven 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 control 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. Through this process control device and control method, the cause of variation in a device structure is detected by measuring the pressure affected by its environment before the device is manufactured before trial modeling, and a thermal treatment is carried out in a semiconductor manufacturing equipment adding a thermal treatment time variation to a prescribed thermal treatment time based on the detected pressure variation after a temperature rise time elapses, whereby a film can be restrained from varying in thickness due to the influence of a pressure, and a process time can be stably controlled without causing a time lag without making a pilot model.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for controlling a semiconductor process, and more particularly to a method for realizing a stable semiconductor device structure in a semiconductor process.

[0002]

2. Description of the Related Art In recent years, as the degree of integration of semiconductor integrated circuits has increased, the oxide film thickness and C
A minute variation in the VD film thickness or the like causes an erroneous operation of the circuit, thereby lowering the product yield.

In a conventional semiconductor manufacturing apparatus, the thickness of a thermal oxide film or a normal pressure CVD film varies due to the influence of the atmospheric pressure, which causes instability of semiconductor circuit characteristics due to a change in semiconductor device structure. Was. Hereinafter, the conventional technology and its problems will be described using a thermal oxidation furnace as an example.

The thickness of the thermal oxide film is controlled by an oxidizing gas pressure in an oxidizing atmosphere, an oxidizing temperature, an oxidizing time, and the like. The oxidizing gas pressure is affected by an atmospheric pressure in an environment where a thermal oxidizing furnace is placed. That is, when the atmospheric pressure is high, the pressure of the oxidizing gas also increases, and the density of the oxidizing agent increases, so that the oxidation rate increases. Conversely, when the atmospheric pressure is low, the oxidizing gas pressure is low, and the oxidation rate is low. For this reason, even if oxidation is performed in a thermal oxidation furnace while the process control parameters during oxidation are kept constant, the oxidation rate fluctuates due to fluctuations in the atmospheric pressure, and the oxide film thickness varies.

FIG. 6 is a view for explaining a conventional film thickness control process. In order to suppress the film thickness variation, in a quality check (hereinafter, referred to as QC) performed at predetermined time intervals, first, oxidation is 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, the 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 control unit that controls the process 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 described above, since the structural change is observed and corrected after performing the oxidation process, the correction is performed after the process change actually occurs.
A sufficiently stable device structure could not be obtained according to the time interval of management. On the other hand, in recent years, as the miniaturization of semiconductor devices progresses, the influence of minute fluctuations in the device structure on device characteristics is increasing.

On the other hand, in recent years, utilization of Si layers epitaxially grown on Si substrates has been expanding. In the case of a fine Si device, control of the thickness of the epitaxial layer is important for controlling the structure. In a CVD process such as an epitaxial process, a dangerous gas such as a Si compound is used.
The D device is designed as a closed system. However, normal pressure CV
In the case of D, it is not in direct contact with the atmospheric pressure as in the case of the open system, but the exhaust side is indirectly in contact with the outside world through the exhaust gas detoxification device. Therefore, in atmospheric pressure CVD, when the atmospheric pressure changes, the atmospheric pressure in the chamber changes under the influence of the change, and the deposited film thickness fluctuates even if other conditions are the same. Therefore, the same problem as in the case of forming a thermal oxide film occurs.

On the other hand, a semiconductor integrated circuit development base and a developed integrated circuit production base are often located in regions under different weather conditions, and recently, production bases are located outside of Japan. Often. Therefore, even if a film is formed under the same conditions as the film formation control set at the development site, the thickness of the oxide film or the atmospheric pressure CVD film is not uniform depending on the region because the atmospheric pressure value is different. Had become. Therefore, in order to obtain the same device structure, different process control parameter corrections are required in each region, which hinders stable start of mass production at each production site.

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

[0010]

As described above, in the conventional semiconductor process control, in order to suppress the film thickness variation, in the QC management performed at a predetermined time interval, the structural variation is known and corrected after the manufacturing process. Therefore, the correction is performed after the process variation actually occurs, and a sufficiently stable device structure cannot be obtained according to the time interval of the QC management. On the other hand, in recent years, as the miniaturization of semiconductor devices progresses, the influence of minute fluctuations in the device structure on device characteristics is increasing.

On the other hand, a semiconductor integrated circuit development base and a production base are often located in regions under different weather conditions. For this reason, even if the film is formed under the same conditions as the film formation control defined at the development site, the thickness of the oxide film or the atmospheric pressure CVD film is not uniform in some regions because the atmospheric pressure value is different. Becomes

In view of the fact that the atmospheric pressure affects the film thickness variation, it is necessary to control the film thickness closer to the cause than by the QC data. SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to detect a cause of a device structure variation before performing a process process and to realize a semiconductor process control apparatus and a control method for realizing a stable semiconductor process. Is to provide.

[0013]

According to a first aspect of the present invention, there is provided a semiconductor process control apparatus for measuring a pressure value in a semiconductor manufacturing apparatus for manufacturing a semiconductor device by heat treatment in a normal pressure atmosphere or in an installation environment of the apparatus. Means for calculating, a heat treatment time fluctuation value for suppressing a device structure fluctuation due to the fluctuation of the measured atmospheric pressure value, and a heat treatment time set in advance in the semiconductor manufacturing apparatus, the calculated heat treatment time Means for adding a variation value after an elapse of a time period for elevating the temperature in the semiconductor manufacturing apparatus from an initial temperature to a predetermined heat treatment temperature to correct the heat treatment time.

According to a second aspect of the present invention, in the semiconductor process control apparatus, the semiconductor manufacturing apparatus is an oxidation furnace.
The heat treatment is thermal oxidation, and when performing thermal oxidation for an oxidation time of T minutes, when the measured pressure value is x% of a preset pressure value, the heat treatment time fluctuation value ΔT is changed by the pressure value fluctuation. The variation is given as a magnitude for correcting a variation given to the thickness of the thermal oxide film. For example, ΔT = T {1− (x / 100) ² } /
(X / 100) ² ... (A).
(A) is an equation obtained in an ideal case in which film formation is performed according to a supply-limiting rate due to diffusion of an oxidant in a thermal oxide film. If (a) does not hold because the thermal oxidation conditions deviate from the ideal supply rate control, ΔT determined corresponding to each thermal oxidation condition is given.

Preferred embodiments of the present invention are as follows. (1) 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.

According to a third aspect of the present invention, in the semiconductor process control apparatus, the semiconductor manufacturing apparatus is a normal pressure CVD apparatus, the heat treatment is a normal pressure CVD processing, and T pressure normal pressure CVD is performed. When the measured atmospheric pressure value is x% of the preset atmospheric pressure value, the heat treatment time fluctuation value ΔT is given as a magnitude for correcting the fluctuation that the fluctuation of the atmospheric pressure value gives to the thickness of the CVD film. For example, ΔT = T ｛1− (x / 10
0)｝ / (x / 100) (b).

(B) is an equation obtained in an ideal case in which a film is formed in accordance with the supply rate in proportion to the concentration of the reaction gas on the surface of the deposited film in the dilution CVD.
If the CVD conditions deviate from the ideal supply rate control and (b) does not hold, ΔT determined for each CVD condition is given.

Preferred embodiments of the present invention are as follows. (1) 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 film forming temperature and stabilized at the film forming temperature.

According to a fourth aspect of the present invention, there is provided a semiconductor process control method for manufacturing a semiconductor device using a semiconductor manufacturing apparatus having a function of performing a heat treatment in a normal pressure atmosphere.
A pressure value in the semiconductor manufacturing apparatus is measured, and a fluctuation value of the heat treatment time is changed from an initial temperature to a predetermined heat treatment temperature during a heat treatment time preset in the semiconductor manufacturing apparatus according to the measured pressure value. It is characterized in that it is added and corrected after the elapse of the time for raising the temperature inside.

(Operation) The operation of the present invention will be described below with reference to FIG. When heat treatment is performed in a 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 section 51 measures the atmospheric pressure value in the manufacturing apparatus or its installation environment affected by the atmospheric pressure value of this environment, and converts the measured value to the heat treatment time fluctuation value calculating section 5.
Output to 2. The heat treatment time fluctuation value calculation unit 52 calculates a heat treatment time fluctuation value for suppressing the fluctuation of the device structure based on the input atmospheric pressure value in the manufacturing apparatus or the installation environment thereof, and outputs the heat processing time fluctuation value to the control unit 53. The control unit 53 controls the semiconductor process by adding a fluctuation value of the heat treatment time to the heat treatment time after the temperature rise time in the apparatus in the heat treatment of the semiconductor manufacturing apparatus.

Control for changing the pressure value itself of each semiconductor manufacturing apparatus is complicated and involves instability. This is because, when the pressure around the wafer is controlled using a gas system that involves some kind of pressure control, by-products in the process accumulate in the piping, and it is difficult to control accurately due to this effect.

Therefore, the heat treatment time during which stable and fine control can be performed is used as a correction process control parameter for reducing device structure variation. By performing the heat treatment for the heat treatment time to which the corrected time is added, the film thickness variation affected by the atmospheric pressure value can be suppressed without making a prototype. Further, the control variation of the set value of the time is extremely small, so that a more accurate correction can be performed as compared with the case where the pressure and the temperature are corrected. Further, by adding this correction time after the time when the temperature is raised to the predetermined heat treatment temperature, it is possible to control the process time stably.

[0023]

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

The atmospheric pressure value measuring section 2 is a section for measuring the atmospheric pressure value of the environment, and is substituted by a section for measuring the atmospheric pressure value in the CR in the CR management mechanism. Oxidation furnace 1 is in CR, C
Since the pressure in R is controlled by the pressure difference from the outside, the pressure in CR is affected by the atmospheric pressure. Therefore, the atmospheric pressure value measuring section 2 detects the cause of the device structure fluctuation affected by the environmental atmospheric pressure value by measuring the atmospheric pressure value of the CR inside detecting section 6.

The oxidation time fluctuation value calculation section 3 is a section for calculating the oxidation time fluctuation value based on the atmospheric pressure in the CR, which is the measurement value of the atmospheric pressure value measurement section 2. A correction value for suppression is given according to the oxidation condition. For example, when performing thermal oxidation for an oxidation time of T minutes, when the pressure value measured by the pressure value measuring unit 2 is x% of the preset pressure value, the oxidation time fluctuation value ΔT is calculated by the following equation (1). ) To give.

ΔT = T {(1− (x / 100) ² )} / (x / 100) ² (1) Formula (1) is supplied because the oxidant diffuses in the thermal oxide film. This is an equation obtained in an ideal case where film formation is performed according to the rate-determining. Therefore, for example, in the case of including a portion that does not depend on the supply rule such as in the case of the initial oxidation of dry oxidation, the thermal oxidation condition deviates from the ideal supply control and the formula (1)
Does not hold, a variation value ΔT corresponding to each thermal oxidation condition is given without being limited to the equation (1).

The control unit 4 controls the controller 5 by adding the oxidation time fluctuation value given by the oxidation time fluctuation value calculation unit 3 to the oxidation time set in the control unit 4 in advance. The manufacturing process is performed in the oxidation furnace 1 with the oxidation time varied so as to suppress the variation of the oxide film thickness.

Next, an example of time control of the temperature change in the furnace when performing thermal oxidation is shown in FIG. 2A shows the case of time control without adding the oxidation time fluctuation value, and FIG. 2B shows the case of time control with the oxidation time fluctuation value added. The horizontal axis represents time, and the vertical axis represents 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 a predetermined oxidation temperature. The time during which the wafer is supplied to the wafer, 24 is the time when other processing such as inert annealing is performed as needed, and 25 is the time for lowering the temperature to around normal temperature.

In the control for reducing the variation used in the present embodiment, as shown in FIG. 2B, the oxidation time fluctuation value Δ calculated by the oxidation time fluctuation value calculation unit 3 by the equation (1).
T is given as a correction to a predetermined time of 23, and the oxidation time is set to 26.

The operation of the semiconductor process control device according to the above embodiment will be described. When thermal oxidation is performed in the oxidation furnace 1, the pressure in the CR where the oxidation furnace 1 is installed is affected by the atmospheric pressure value. The oxidation furnace 1 is in the CR and the pressure in the CR is controlled, but the pressure in the CR is controlled by the pressure difference from the outside, so the pressure in the CR is affected by the atmospheric pressure value. Further, the pressure in the oxidation furnace 1 is affected by not only the pressure in the CR but also the pressure reduction value on the exhaust side, but the pressure reduction value on the exhaust side is very weak. That is, it is extremely small as compared with the fluctuation of the atmospheric pressure. Therefore, the oxidation rate fluctuates under the influence of the atmospheric pressure. Accordingly, the atmospheric pressure value measuring unit 2 measures the atmospheric pressure in the CR affected by the atmospheric pressure value of the environment, which causes the oxide film thickness variation, and outputs the measured value to the oxidation time variation value calculating unit 3.

The oxidation time fluctuation value calculation unit 3 calculates the oxidation time fluctuation value for suppressing the fluctuation of the device structure based on the input atmospheric pressure value in the CR according to the equation (1).
Output to This makes it possible to predict an oxidation time variation value that suppresses a film thickness variation caused by a value of the atmospheric pressure variation without going through a process.

In the thermal oxidation in the oxidation furnace 1, the control unit 4 controls the controller 5 to perform a manufacturing process by adding an oxidation time fluctuation value to an oxidation time after a heating time in the furnace. The controller 5 performs a manufacturing process in the oxidation furnace 1 in which the structural variation is suppressed without time delay based on the signal input from the control unit 4.

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

In the process control based on the oxidation time corrected by the oxidation time fluctuation value, a process time component corresponding to a process in which an oxide film is mainly formed stably is corrected (2).
6). When the oxidizing agent is supplied 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 the predetermined film thickness is performed as shown in FIG.
As shown in (b), the process is performed by adding an oxidation time variation value ΔT to a time T corresponding to 23, which is a process of mainly forming an oxide film, and the corrected oxidation time is T + ΔT. By making the process shown in 23 the object of the control, stable process time control for suppressing the film thickness variation due to the atmospheric pressure variation can be obtained.

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

On the other hand, the variation in gas pressure depends on the atmospheric pressure in the case of a normal pressure device. Here, the atmospheric pressure does not depend on each device, and is a common element for each device installed in the same environment, and the internal pressure fluctuation in each device is high. Therefore, as shown in the present embodiment, by controlling the air pressure value to cancel out the fluctuation value of the device structure, it is possible to efficiently remove the product variation.

FIG. 3 is a diagram showing a simulation comparison of the effect of a minute change in the atmospheric pressure on the oxide film thickness by changing the process parameters such as the oxidizing temperature, the oxidizing gas pressure and the oxidizing time. An oxide film is formed in a dry O ₂ atmosphere at 950 ° C., and a temperature rise rate of 10 is set by an FTP (Fast Thermal process).
0 ° C./min, oxidation time 9.5 minutes. The sensitivity analysis simulation was performed by giving the following parameter variations, and the vertical axis indicates the film thickness.

Oxidation temperature 3σ = 1 ° C., O ₂ gas pressure 3σ =
20 mb, oxidation time 3σ = 1 second In FIG. 3, reference numeral 31 denotes a reference oxide film thickness formed by preset process parameters, 32 denotes an oxide film thickness when an oxidation temperature variation is given, and 33 denotes a gas thickness variation. The oxide film thickness when given, and 34 indicates the oxide film thickness when the oxidation time variation is given. High sensitivity of film thickness to gas pressure variation with temperature variation ± 0.2 nm at 3σ
It can be seen that a degree of variation results from the gas pressure variation. This variation value is ± 50 m for a Si MOSFET.
A threshold voltage fluctuation of about V occurs, which causes a reduction in yield in device manufacturing. On the other hand, since the variation in the film thickness when the oxidation time variation is given is small, the use of the oxidation time as a correction parameter for the process control enables highly accurate correction.

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

In the process control based on 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 formed stably is corrected, so that the oxide film thickness variation may occur. No oxidation process can be realized.

Furthermore, since the variation in the time control is small, the influence on the oxide film thickness is smaller than the variation in the temperature and the variation in the gas pressure. By using the oxidation time as a correction parameter, stable and fine process control is possible. is there. (Second Embodiment) FIG. 4 is a diagram showing an overall configuration of a semiconductor process control device according to a 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 a pressure value measuring section 42, a deposition time fluctuation value calculating section 43, Control unit 4
4 This atmospheric pressure epitaxial growth CVD
The device 41 is a non-open system, and the outside and the inside of the device 41 are not directly in contact with each other, but are indirectly connected to the outside via an exhaust gas detoxification device 46 provided for exhausting gas introduced at the time of CVD. Is in contact with

The atmospheric pressure value measuring section 42 is a part for measuring the atmospheric pressure in the installation environment of the CVD apparatus 41, that is, the atmospheric pressure value in the CVD chamber which is affected by the atmospheric pressure of the environment which causes the device structure fluctuation.

The deposition time fluctuation value calculating section 43 is a section which gives a deposition time fluctuation value according to the process conditions, which suppresses the fluctuation of the deposited film thickness due to the fluctuation of the atmospheric pressure value obtained by the atmospheric pressure value measuring section 42. For example, when normal pressure epitaxial growth is performed using a silane chloride-based gas using 80% N ₂ as a diluent gas, the pressure value measured by the pressure value measuring unit 42 is preset when performing epitaxial growth for T minutes. When the pressure is x% of the pressure value, the deposition time fluctuation value is calculated by the following equation (2).
Give in.

ΔT = T {1− (x / 100)} / (x / 100) (2) In the dilution CVD, the film is formed in accordance with the supply rate in proportion to the reaction gas concentration on the surface of the film after deposition. This is an equation obtained for an ideal case where generation is performed. Therefore,
Equation (2) deviates from the ideal supply rate-limiting CVD conditions such as the rate-limiting film formation conditions when the reaction gas concentration is higher.
Does not hold, ΔT determined according to each CVD condition is given without being limited to the equation (2).

The control unit 44 includes a deposition time fluctuation value calculation unit 43
The controller 45 controls the controller 45 by adding the deposition time fluctuation value given by the control unit 44 to the deposition time preset in the control unit 44. The manufacturing process is performed with the deposition time varied so as to be suppressed.

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

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

The operation of the semiconductor process control device according to the above embodiment will be described. When CVD is performed in the atmospheric pressure epitaxial growth CVD apparatus 41, the internal pressure in the CVD apparatus 41 is affected by the atmospheric pressure value because the CVD apparatus 41 is indirectly in contact with the outside via the exhaust gas detoxification apparatus 46. 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 calculating section 43 calculates the deposition time fluctuation value for suppressing the fluctuation of the device structure based on the input atmospheric pressure value by the equation (2), and outputs it to the control section 44. Thereby, the CV generated by the value of the atmospheric pressure fluctuation
The deposition time fluctuation value that suppresses the D film thickness fluctuation can be predicted without trial production.

The control unit 44 controls the normal pressure epitaxial growth C
In the CVD of the VD apparatus 41, the controller 45 is controlled so as to perform a manufacturing process by adding a deposition time variation value to a deposition time after a heating time in the chamber. The controller 45 performs, in the CVD apparatus 41, a manufacturing process in which structural variations are suppressed without delay based on a signal input from the control unit 44.

In the process control based on the time corrected by the correction value obtained by the deposition time fluctuation value calculating section 43, the process is realized by correcting a process time component corresponding to a process in which a CVD film is mainly formed stably. And CVD
It is possible to realize a CVD process in which a film thickness does not vary.

As described above, by using the atmospheric pressure value measuring unit 42, it is possible to directly obtain and control the value of the cause of the variation, as compared with the conventional indirect control method using a monitor wafer, and to achieve a higher control. The thickness variation can be suppressed with high accuracy. Further, since the deposition time correction value can be immediately obtained by the deposition time variation value calculating section 43 in conjunction with the variation of the cause, the deposition time correction can be performed without time delay. Further, the control unit 44 can reduce the load of the work of performing minute correction under the process conditions using the conventional monitor wafer.

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

In this embodiment, the case where the present invention is applied to a normal-pressure epitaxial growth CVD apparatus has been described, but any normal-pressure CVD apparatus affected by atmospheric pressure may be used.
Also, in the first and second embodiments, the case where the manufacturing process time variation value is given by the equations (1) and (2) has been described.
Depending on the nature of the reaction, it is also possible to select formulas (1) and (2) to obtain a manufacturing process time variation.

Further, the present invention is not limited to a normal pressure CVD apparatus or a thermal oxidation furnace, and if a heat treatment apparatus affected by the atmospheric pressure is given, based on experience, a formula for giving a heat treatment time fluctuation value, it is possible to provide a diffusion apparatus or the like. Is also applicable.

It is also possible to provide a numerical value table for a manufacturing processing time fluctuation value which suppresses a device structure fluctuation due to a fluctuation in atmospheric pressure value depending on process conditions. In this case, when the nature of the reaction is unknown during the film formation process, the device structure fluctuation due to the fluctuation of the atmospheric pressure value is experimentally obtained, and when the experimental result data is stored and used, the film thickness fluctuation due to the fluctuation of the atmospheric pressure value is used. Can be obtained. Third Embodiment A third embodiment relates to the development of a semiconductor memory manufacturing process and the transfer of manufacturing technology to a manufacturing base. That is, semiconductor memory is first manufactured at the development base,
In this case, 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, MOSF forming a semiconductor memory
An example in which a gate oxide film of ET is formed will be described.

First, a reference CR internal pressure value is determined at the development base, and a gate oxide film thickness value of the MOSFET is determined based on the pressure value. The oxidation furnace for performing gate oxidation includes: (A) a pressure measurement unit for measuring a pressure variation in the CR at the development site; and (B) an oxidation time variation for calculating a variation in the gate oxide film thickness caused by the variation. A calculating unit;
(C) A control unit for realizing an oxidation process control in the oxidation furnace for performing the oxidation using the oxidation time corrected by the correction value obtained in (B) is installed. In addition, these (A)-
(C) shows the atmospheric pressure value measuring unit 2 and the first embodiment.
It corresponds to the oxidation time fluctuation value calculation unit 3 and the control unit 4.

At the development site, a semiconductor memory manufacturing process is developed using (A) to (C), and gate oxidation is performed using an oxidation time corrected by the correction value calculated in (B). Then, the process parameters are set so that the magnitude of the variation of other device structure parameters due to this correction does not cause instability in the circuit characteristics.

After the development of the semiconductor process as described above, 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, the manufacturing technology is launched using the same (B) and (C) as those used at the development base. In launching this manufacturing technology, it is not necessary to find the optimum control parameters through trial and error as in the past, and if only the reference value in the CR of the manufacturing base is obtained by (A ′), the same as in the development base, Production can be started.

As a result, variations in integrated circuit characteristics due to differences in device structure based on differences in atmospheric pressure values in a plurality of regions can be suppressed, and transfer of a manufacturing process developed at a development base to a manufacturing base can be achieved at an early stage. realizable. The present invention can be applied to any process in which a heat treatment such as CVD is performed in addition to the gate oxide film forming process.

[0061]

As described above, according to the semiconductor process control apparatus and control method of the present invention, the cause of device structure fluctuation can be detected before trial production by measuring the atmospheric pressure value affected by the environment. Then, based on the detected atmospheric pressure fluctuation value, a heat treatment time fluctuation value is added after the elapse of the temperature rise time in the semiconductor manufacturing apparatus, and heat treatment is performed, thereby making a prototype of the film thickness fluctuation affected by the air pressure value. And the process time can be controlled stably without a time delay.

Since the heat treatment time which can be controlled with high precision is used as a correction parameter for controlling the semiconductor process,
Low sensitivity to variations in parameters facilitates control.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of an oxidation furnace control device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a furnace temperature in the embodiment.

FIG. 3 is a diagram showing the influence of process parameter variations on film thickness.

FIG. 4 is a diagram showing an entire configuration of a normal-pressure epitaxial growth CVD control apparatus according to a second embodiment of the present invention.

FIG. 5 is a diagram illustrating the gist of the present invention.

FIG. 6 is a diagram illustrating a conventional film thickness control process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Oxidation furnace 2, 42 ... Atmospheric pressure value measurement part 3 ... Oxidation time fluctuation value calculation part 4, 44 ... Control part 5, 45 ... Controller 31 ... Reference oxide film thickness 32 ... Oxide film thickness due to oxidation temperature variation 33 ... Oxide film thickness due to gas pressure variation 34 ... Oxide film thickness due to oxidation time variation 41 ... Normal pressure epitaxial growth CVD device 43 ... Deposition time variation calculation unit 46 ... Exhaust gas detoxification device

Claims (4)

[Claims] 1. A means for measuring a pressure value in a semiconductor manufacturing apparatus for manufacturing a semiconductor device by a heat treatment in a normal pressure atmosphere or in an installation environment of the apparatus, and suppressing a device structure change due to a change in the measured pressure value. Means for calculating a heat treatment time fluctuation value for performing a heat treatment time preset in the semiconductor manufacturing apparatus, and raising the calculated heat treatment time fluctuation value from the initial temperature to a predetermined heat treatment temperature in the semiconductor manufacturing apparatus. A means for correcting the heat treatment time by adding the heat treatment time after the elapse of the time for heating. 2. The semiconductor manufacturing apparatus is an oxidation furnace, wherein the heat treatment is thermal oxidation. When performing thermal oxidation for an oxidation time of T minutes, the measured pressure value is an average value of a preset pressure value. ^2. The semiconductor process control according to claim 1, wherein the heat treatment time fluctuation value ΔT is given based on ΔT = T {1− (x / 100) ² } / (x / 100) ² when x% apparatus. 3. The semiconductor manufacturing apparatus is a normal-pressure CVD apparatus, and the heat treatment is a normal-pressure CVD process. When performing normal-pressure CVD for T minutes, the measured pressure value is equal to a predetermined pressure value. 2. The semiconductor process control device according to claim 1, wherein when x%, the heat treatment time fluctuation value ΔT is given based on ΔT = T {1− (x / 100)} / (x / 100). 4. When manufacturing a semiconductor device using a semiconductor manufacturing apparatus having a function of performing a heat treatment in a normal pressure atmosphere, a pressure value in the semiconductor manufacturing apparatus or an installation environment of the apparatus is measured, and the measured pressure value is measured. In the heat treatment time set in advance in the semiconductor manufacturing apparatus in accordance with the above, a correction value by adding a variation value of the heat treatment time after a lapse of time for raising the inside of the semiconductor manufacturing apparatus from the initial temperature to a predetermined heat treatment temperature. A semiconductor process control method characterized by the following.