JP5815361B2 - Substrate processing control device, substrate processing control method, control program, and readable storage medium - Google Patents

Description

  The present invention relates to a substrate processing control apparatus and a substrate processing control method for etching processing in the manufacture of semiconductor products, a control program in which processing procedures for causing a computer to execute each step of the substrate processing control method are described, and the control program The present invention relates to a computer-readable readable storage medium in which is stored.

  In order to manufacture a semiconductor integrated circuit, various types of films are formed on a semiconductor substrate, or various types of films formed on a semiconductor substrate are etched into a predetermined shape. In the plasma etching apparatus, various etching processes such as a silicon oxide film, a silicon nitride film, and a polysilicon film are performed.

  Conventionally, the etching process of the semiconductor substrate is performed based on a predetermined recipe, and after the lot process is completed, the line width and the film thickness measurement result are inspected. If there is an abnormality in the line width or film thickness, before starting the processing of the next lot, RF power (RF power), pressure in the chamber, flow rate of gas introduced into the chamber, Various process parameters such as temperature are corrected, and processing is performed based on a new recipe from processing of the next lot.

  In recent years, abnormal values have been detected by independently monitoring a plurality of various process parameters of the apparatus such as high-frequency power (RF power), pressure in the chamber, flow rate of gas introduced into the chamber, temperature in the chamber, etc. In such a case, a system has been constructed in which the processing of the apparatus can be stopped and a processing abnormality can be detected at an early stage. This is disclosed in Patent Document 1.

JP 2002-203835 A

  In the conventional semiconductor substrate etching process, the processing result of the semiconductor substrate is inspected after the lot processing, and a defective product is manufactured even if an abnormality in the processing state on the semiconductor substrate is detected during the process. Thus, there was a problem that the yield was lowered.

  In recent years, in the above conventional semiconductor substrate etching process, the management specifications for each process parameter (for example, power, temperature, pressure, gas flow rate, RF reflected wave, etc.) at the time of processing in the etching apparatus in each process. Is set. When a value outside the set specification range is detected for each process parameter, the etching process of the etching apparatus is stopped. It is necessary to set specifications for each of a large number of process parameters, and even if the characteristic value of the etched wafer is within the normal range, the etching process of the apparatus may stop depending on the value of one process parameter. This causes a decrease in productivity. On the other hand, even if the characteristic value is outside the normal range, the equipment may not stop, resulting in a decrease in yield. As described above, it is difficult to set an optimum specification based on productivity and yield, and there is a problem that the influence on the yield cannot be predicted because the characteristic value is unknown.

  That is, the process parameters of the etching apparatus such as the high-frequency power, the pressure in the chamber, the flow rate of the gas introduced into the chamber, and the temperature in the chamber are independently monitored, and the characteristic amount of the semiconductor substrate of each process parameter Even if one of the multiple process parameters falls outside the specification range, there is no effect on the characteristics of the semiconductor substrate even if there is no effect on the characteristics of the semiconductor substrate. Since the processing is stopped, there is a problem that productivity is unnecessarily lowered.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and includes a substrate processing control apparatus and a substrate processing control method, such as an etching process, capable of improving yield and productivity in the manufacture of semiconductor devices, and a method for controlling the substrate processing. It is an object of the present invention to provide a control program in which a processing procedure for causing a computer to execute each step is described, and a computer-readable readable storage medium in which the control program is stored.

  The substrate processing control apparatus of the present invention includes a parameter extraction unit that extracts a current state of an apparatus parameter indicating an apparatus operation condition, a feature amount calculation unit that calculates a characteristic amount indicating an apparatus processing result from the current state of the apparatus parameter, A continuation determining unit that determines whether to continue the processing of the device depending on whether the feature amount calculated by the feature amount calculating unit is within a specified range, and the continuation determining unit determines to continue the processing of the device When the predetermined substrate processing is performed, and the continuation determining means determines that the processing of the apparatus is not continued, the processing of the predetermined substrate is stopped, thereby achieving the above object.

  Preferably, when the continuation determination means in the substrate processing control apparatus of the present invention determines that the processing of the apparatus is not continued, the processing of the predetermined substrate is not stopped immediately, but the related apparatus parameters are controlled. In this way, it is determined whether or not the adjustment of the feature amount within the specified range is possible. If the adjustment is impossible, the adjustment determination means for stopping the processing of the predetermined substrate, and the adjustment If possible, adjustment control means for controlling the related apparatus parameters to perform adjustment processing so that the feature amount falls within a specified range and shifts to processing by the parameter extraction means.

  Further preferably, the apparatus parameters in the substrate processing control apparatus of the present invention are: the pressure in the chamber of the apparatus, the gas flow rate introduced into the chamber, the gas pressure for cooling the substrate back surface, the upper electrode RF power, the upper part It includes at least one of the lower electrode RF power for drawing the plasma generated by the electrode, the temperature in the chamber, the processing time, and the number of processed substrates.

  Still preferably, in a substrate processing control apparatus according to the present invention, the feature amount includes at least one of a line width, a film thickness, and a defect density of a circuit pattern formed on the substrate.

  Further preferably, the feature amount in the substrate processing control apparatus of the present invention is calculated from the apparatus parameters using a physical model or a statistical model.

Further preferably, the apparatus parameters in the substrate processing control apparatus of the present invention are: pressure in the chamber (Pressure (mTorr)), four types (Cl ₂ Flow, HBrFlow, O ₂ Flow and CF ₄ Flow) introduced into the chamber. The gas flow rate (sccm), the back-cooling Back-He pressure (Torr), the upper electrode RF power (SourcePowerW), and the lower electrode RF power (BiasPowerW) that draws plasma generated in the upper electrode, and the amount of etch shift relative to the apparatus parameters The prediction formula of the etch shift model as the physical model or statistical model by obtaining a coefficient from the relationship with
Etch Shift Etch Shift = −19.3 + 0.772 × Pressure−0.539 × Cl 2 Flow + 0.0260 × HBr Flow −1.71 × O 2 Flow + 0.271 × CF 4 Flow + 0.0495 × Back−He +0.0215 SourcePower +0.447 × BiasPower
And

Further preferably, the apparatus parameters in the substrate processing control apparatus of the present invention are: pressure in the chamber (Pressure (mTorr)), four types (Cl ₂ Flow, HBrFlow, O ₂ Flow and CF ₄ Flow) introduced into the chamber. The gas flow rate (sccm), the back surface cooling Back-He pressure (Torr), the upper electrode RF power (SourcePowerW), and the lower electrode RF power (BiasPowerW) that draws the plasma generated in the upper electrode, and the etching rate amount corresponding to the apparatus parameters The prediction formula of the etch rate model as the physical model or statistical model by obtaining a coefficient from the relationship with
Etch Rate Etch Rate = 485 + 32.5 × Pressure + 6.89 × Cl2Flow−3.15 × HBrFlow + 13.8 × O2FLow + 8.25 × CF4Flow−5.00 × Back−He + 1.17 SourcePower + 8.86 × BiasP
And

  In the substrate processing control method of the present invention, the parameter extraction means extracts the current state of the apparatus parameter indicating the apparatus operating condition, and the feature amount calculation means indicates the apparatus processing result from the current state of the apparatus parameter. A feature amount calculating step for calculating the feature amount, and a continuation determining means for determining whether to continue the processing of the device depending on whether the feature amount calculated in the feature amount calculating step is within a specified range. The processing of the predetermined substrate is performed when it is determined that the processing of the apparatus is continued in the continuation determination step, and the processing of the predetermined substrate is stopped when it is determined that the processing of the device is not continued in the continuation determination step Thus, the above object is achieved.

  Preferably, when it is determined that the processing of the apparatus is not continued in the continuation determination step in the substrate processing control method of the present invention, the adjustment determination means does not immediately stop the processing of the predetermined substrate. An adjustment determination step of determining whether or not the adjustment of the feature amount within the specified range is possible by controlling an apparatus parameter to be performed, and stopping the processing of the predetermined substrate if the adjustment is impossible If the adjustment is possible, the adjustment control means controls the related apparatus parameter to perform adjustment processing so that the feature amount falls within a specified range, and shifts to the processing by the parameter extraction step. And a control process.

  Further preferably, in the substrate processing control method of the present invention, the apparatus parameters include the pressure in the chamber of the apparatus, the gas flow rate introduced into the chamber, the gas pressure for cooling the substrate back surface, the upper electrode RF power, the upper part It includes at least one of the lower electrode RF power for drawing the plasma generated by the electrode, the temperature in the chamber, the processing time, and the number of processed substrates.

  Still preferably, in a substrate processing control method according to the present invention, the feature amount includes at least one of a line width, a film thickness, and a defect density of a circuit pattern formed on the substrate.

  Further preferably, the feature amount in the substrate processing control method of the present invention is calculated from the apparatus parameter using a physical model or a statistical model.

Further preferably, in the substrate processing control method of the present invention, the apparatus parameters include pressure in the chamber (Pressure (mTorr)), and four types (Cl ₂ Flow, HBrFlow, O ₂ Flow and CF ₄ Flow) introduced into the chamber. The gas flow rate (sccm), the back-surface cooling Back-He pressure (Torr), the upper electrode RF power (SourcePowerW), and the lower electrode RF power (BiasPowerW) that draws plasma generated in the upper electrode, and the amount of etch shift relative to the apparatus parameters The coefficient is calculated from the relationship of the physical model or the prediction formula of the etch shift model as the statistical model,
Etch Shift Etch Shift = −19.3 + 0.772 × Pressure−0.539 × Cl 2 Flow + 0.0260 × HBr Flow −1.71 × O 2 Flow + 0.271 × CF 4 Flow + 0.0495 × Back−He +0.0215 SourcePower +0.447 × BiasPower
And

Further preferably, in the substrate processing control method of the present invention, the apparatus parameters include pressure in the chamber (Pressure (mTorr)), and four types (Cl ₂ Flow, HBrFlow, O ₂ Flow and CF ₄ Flow) introduced into the chamber. The gas flow rate (sccm), the back surface cooling Back-He pressure (Torr), the upper electrode RF power (SourcePowerW), and the lower electrode RF power (BiasPowerW) that draws the plasma generated in the upper electrode, and the etching rate amount corresponding to the apparatus parameters By calculating the coefficient from the relationship, the prediction formula of the etch rate model as the physical model or statistical model,
Etch Rate Etch Rate = 485 + 32.5 × Pressure + 6.89 × Cl2Flow−3.15 × HBrFlow + 13.8 × O2FLow + 8.25 × CF4Flow−5.00 × Back−He + 1.17 SourcePower + 8.86 × BiasP
And

  The control program according to the present invention describes a processing procedure for causing a computer to execute each step of the substrate processing control method according to the present invention, thereby achieving the above object.

  The readable storage medium of the present invention is a computer-readable storage medium storing the control program of the present invention, thereby achieving the above object.

  With the above configuration, the operation of the present invention will be described below.

  In order to improve the yield of semiconductor devices and shorten the delivery time, it is necessary to perform production without waste. For this purpose, a method for controlling a manufacturing apparatus that can predict characteristic values such as a line width, a film thickness, and the number of defects of a substrate which is a semiconductor wafer in a short time with high accuracy is effective.

  In the present invention, the parameter extraction means for extracting the current state of the apparatus parameters indicating the apparatus operating conditions such as pressure and gas flow rate, and the feature amount such as the line width and the film thickness indicating the apparatus processing result from the current state of the apparatus parameters. A feature amount calculating means for calculating and a continuation determining means for determining whether or not to continue the processing of the device depending on whether or not the calculated feature amount is within a specified range, and the continuation determining means determines to continue the processing of the device When the predetermined process is performed and the continuation determination unit determines that the process of the apparatus is not continued, the predetermined process is stopped.

  In addition, when the continuation determination unit determines that the processing of the device is not continued, whether or not the feature amount falls within the specified range by controlling the related device parameter instead of immediately stopping the predetermined processing. Judgment is made on whether or not adjustment is possible. If adjustment is not possible, adjustment determination means for stopping a predetermined process, and if adjustment is possible, the related apparatus parameter is controlled to define the feature amount. Adjustment control means for performing adjustment processing so as to be within the range and shifting to processing by the parameter extraction means.

  In this way, the continuation determination unit determines whether to continue the processing of the device depending on whether the feature amount calculated from the device parameters in the current state by the feature amount calculation unit is within the specified range, or the adjustment control unit It is possible to improve the yield and productivity in the manufacture of semiconductor devices by controlling the device parameters to perform adjustment processing so that the feature amount falls within the specified range.

  As described above, according to the present invention, the continuation determination unit determines whether or not to continue the processing of the device depending on whether or not the feature amount calculated from the device parameter in the current state by the feature amount calculation unit is within the specified range, or adjusts Since the control means controls the related apparatus parameters and performs the adjustment processing so that the feature amount falls within the specified range, it is possible to improve the yield and productivity in manufacturing the semiconductor device.

It is a block diagram which shows the principal part structural example of the etching control apparatus in Embodiment 1 of this invention. 3 is a flowchart for explaining the operation of the etching control apparatus 1 of FIG. 1. It is a longitudinal cross-sectional view which shows the plasma etching apparatus of this Embodiment 1 typically. It is a longitudinal cross-sectional view of the semiconductor device for demonstrating a typical gate etching process (the 1). It is a longitudinal cross-sectional view of the semiconductor device for demonstrating a typical gate etching process (the 2). It is a figure for demonstrating the etch shift model which manages the etch shift amount for line | wire width prediction, Comprising: It is a figure which shows the dependence of the etch shift amount of the vertical axis | shaft with respect to each apparatus parameter of a horizontal axis. It is a figure which shows the relationship between the predicted value of etch shift amount, and an actual value. It is a figure for demonstrating the etching rate model which manages the etching amount for film thickness prediction, Comprising: It is a figure which shows the dependence of the etching rate amount of the vertical axis | shaft with respect to each apparatus parameter of a horizontal axis. It is a figure which shows the relationship between the predicted value of etching amount, and an actual value. It is a figure for demonstrating the defect number model which manages the particle number for defect number prediction, Comprising: It is a figure which shows the particle number per wafer with respect to the cumulative processing number of sheets of an etching apparatus.

  Hereinafter, a substrate processing control method and a substrate processing control apparatus according to a first embodiment of the present invention for manufacturing a semiconductor product will be described in detail with reference to the drawings. In addition, each thickness, length, etc. of the structural member in each figure are not limited to the structure to illustrate from a viewpoint on drawing preparation.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration example of a main part of an etching control apparatus according to Embodiment 1 of the present invention.

  In FIG. 1, an etching control apparatus 1 as a substrate processing control apparatus according to the first embodiment is configured by a computer system, and includes an operation input unit 2 such as a keyboard, a mouse, and a screen input apparatus that allows various input commands. , A display unit 3 that can display various images such as an initial screen, a selection guide screen, and a processing result screen on a display screen in response to various input commands, and a CPU 4 (central processing unit) that performs overall control. Processor), RAM 5 as temporary storage means that works as a work memory when the CPU 4 is started up, a computer-readable readable recording medium (storage means) in which a control program for operating the CPU 4 and various data used therefor are recorded. ) As a ROM 6.

  The CPU 4 performs apparatus operation conditions such as pressure, temperature, RF power, and gas flow rate based on a control program read from the ROM 6 into the RAM 5 and various data used for the input command from the operation input unit 2. A parameter extracting unit 41 for extracting the current state of the apparatus parameter (process parameter) indicating the characteristic amount, and a feature amount for calculating a characteristic amount indicating the apparatus processing result such as the line width and film thickness after the etching process from the current state of the apparatus parameter A calculating unit 42 and a continuation determining unit 43 that determines whether or not to continue the processing of the device depending on whether or not the calculated feature amount is within a specified range, and the continuation determining unit 43 continues the processing of the device within the specified range. When the determination is made, a predetermined etching process is performed, and when the continuation determination unit 43 determines that the apparatus process is not continued outside the specified range, To stop the etching process.

  Preferably, the CPU 4 determines that the continuation determination unit 43 performs the processing of the apparatus based on an input command from the operation input unit 2 and a control program read from the ROM 6 to the RAM 5 and various data used for the control program. If it is determined not to continue, instead of immediately stopping the predetermined etching process, it is determined whether it is possible to adjust whether the feature amount is within the specified range by controlling the relevant apparatus parameters, If the adjustment is impossible (NO), the adjustment determination means 44 for stopping the etching process, and if the adjustment is possible (YES), the related apparatus parameters are controlled to make the feature amount within the specified range. Adjustment control means 45 for performing the adjustment processing as described above.

  The parameter extracting means 41 extracts the current state of the apparatus parameters of the substrate etching process for the substrate on which the circuit pattern composed of at least one pattern region is formed. The current state of the apparatus parameters will be described later in more detail. The current pressure in the chamber (mTorr), the flow rate of gas introduced into the chamber (sccm), the He pressure for backside cooling (Torr), the upper electrode RF It includes at least one of power (high-frequency power W), lower electrode RF power (high-frequency power W) for drawing plasma generated by the upper electrode, temperature in the chamber, processing time, and the number of processed substrates.

  The feature amount calculation means 42 calculates the feature amount for each substrate from the apparatus parameters of each etching process. The feature quantity for each substrate includes any of the line width, film thickness, defect density, and the like of the circuit pattern formed on the substrate. For the calculation of the feature amount for each substrate, a physical model or a statistical model, which will be described in detail later, is used from the apparatus parameters of each etching process of the substrate.

  The continuation determination unit 43 stops the processing of the apparatus when the calculated feature value for each board is outside the set specified range, and the calculated feature value for each board is within the set specified range. In this case, the etching process of the apparatus is continued. Conventionally, the etching process of the apparatus is stopped when at least one of a large number of apparatus parameters deviates from the predetermined specified range. However, in the first embodiment, one of the apparatus parameters falls within the predetermined range. Even if it has been removed, the etching process of the apparatus will not be stopped unless the characteristic amount for each substrate calculated from a plurality of or a large number of apparatus parameters is set. Therefore, the process such as the etching process of the apparatus is not stopped. And the productivity including yield is improved.

  Preferably, in the continuation determination unit 43, when a device parameter having a large change in the feature value for each substrate with respect to a change in the device parameter is out of a predetermined range, it may be defective unless the processing of the device is stopped. In many cases, however, the predetermined etching process is not stopped immediately, but it is determined whether the feature amount can be adjusted by controlling the related apparatus parameters. If the adjustment is impossible (NO), an adjustment determination means 44 for stopping the etching process can be provided.

  The adjustment determination unit 44 controls each related apparatus parameter to determine whether or not at least one of the feature amounts of the line width, the film thickness, and the defect density falls within a specified range, that is, whether the adjustment is possible. .

  The adjustment control means 45 controls each related apparatus parameter, performs adjustment processing so that the feature values of the line width, film thickness, and defect density are within the specified ranges, and proceeds to the processing by the parameter extraction means 41. To do.

  The ROM 6 is configured by a readable recording medium (storage means) such as a hard disk, an optical disk, a magnetic disk, and an IC memory. The control program and various data used for the control program may be downloaded to the ROM 6 from a portable optical disk, a magnetic disk, an IC memory, or the like, or may be downloaded to the ROM 6 from a hard disk of a computer, or wirelessly, wired, or the Internet. It may be downloaded to the ROM 6 via the above. A control program in which a processing procedure for causing a computer to execute an etching control method to be described later is stored in a computer-readable readable storage medium, and etching control is performed by a computer (CPU 4).

  Next, an etching control method as a substrate processing control method in the manufacture of semiconductor products will be described.

  As a substrate processing control method according to the first embodiment, an etching control method using the etching control apparatus 1 is configured such that the parameter extraction unit 41 is a substrate (wafer) on which a circuit pattern including at least one pattern region is formed. The parameter extraction step for extracting the apparatus parameters of the etching process, the feature amount calculating means 42 calculates the feature amount calculating process for calculating the feature amount for each substrate from the apparatus parameters of each etching process, and the continuation determining means 43 are calculated. A process for determining whether to continue the process of the apparatus based on the target value of the characteristic amount by changing the apparatus parameter, or to stop the process of the apparatus when the calculated characteristic amount for each substrate is outside the set specified range; Have

  Preferably, in the etching control method, the continuation determination means 43 is based on a control program read from the ROM 6 into the RAM 5 and various data used therefor in addition to an input command from the operation input unit 2. If it is determined that the process is not continued, the predetermined etching process is not stopped immediately, but the adjustment determination unit 44 controls whether or not the feature amount falls within the specified range by controlling each related apparatus parameter. If the adjustment is impossible (NO), the adjustment determination step for stopping the etching process, and if the adjustment is possible (YES), the adjustment control means 45 includes the related steps. An adjustment control step for adjusting the apparatus parameters so that the feature amount falls within the specified range.

  In the etching process of a semiconductor substrate, the parameters of the etching apparatus are calculated from the feature quantities of the semiconductor product such as the line width, the film thickness, and the number of defects measured after the process. As a result, when it is recognized that the processing state is appropriate (feature amount is within the specified range), the etching process on the semiconductor substrate is continued as it is, and the etching processing state is inappropriate (the feature amount is outside the specified range). If it is recognized, at least one of apparatus parameters (process parameters) for the semiconductor substrate is changed or the etching process for the semiconductor substrate is stopped. In this way, by taking appropriate measures during the etching process on the semiconductor substrate, it is possible to improve the yield in the manufacture of the semiconductor device, and to minimize the decrease in productivity.

  The operation of the above configuration will be described below.

  FIG. 2 is a flowchart for explaining the operation of the etching control apparatus 1 of FIG.

  As shown in FIG. 2, first, in step S1, the parameter extraction means 41 monitors the current status of the apparatus parameters. In this monitoring, the parameter extraction means 41 detects the current state of apparatus parameters such as chamber pressure and gas flow rate in the substrate etching process for a substrate (semiconductor wafer) on which a circuit pattern consisting of at least one pattern region is formed. To do.

  Next, at the same time in steps S2 to S4, the feature quantity calculation means 42 uses the physical model or statistical model described later from each apparatus parameter extracted in each etching process of the substrate, and in step S2, the feature quantity line width is calculated. The etch shift is calculated and predicted. In step S3, the etch rate of the film thickness of the feature amount is calculated and predicted. In step S4, the defect density of the feature amount is predicted from the number of processed substrates in the apparatus parameter.

  Subsequently, in steps S5 to S7, the continuation determination unit 43 performs continuation determination processing at the same time. That is, in step S5, the continuation determination unit 43 determines whether the etch shift amount of the line width predicted in step S2 is within a specified range, that is, whether the line width predicted in step S2 is “OK”. In step S6, the continuation determination unit 43 determines whether or not the etching rate of the film thickness predicted in step S3 is within a specified range, that is, whether or not the film thickness predicted in step S3 is “OK”. In step S7, the continuation determination unit 43 determines whether the number of defects (number of particles) predicted in step S4 is within a specified range, that is, whether the defect density predicted in step S4 is “OK”.

  Further, in step S8, it is continued whether or not the line width predicted in step S2 is “OK”, the film thickness predicted in step S3 is “OK”, and the defect density predicted in step S4 is “OK”. The determination means 43 determines. When all of the feature values are “OK”, the continuation determination unit 43 can execute the substrate etching process in the next step S9 to obtain a good line width, film thickness, and defect density.

  Next, when at least one of the continuation determination processes by the continuation determination unit 43 is “NO” in steps S5 to S7, that is, at least one of the line width, the film thickness, and the defect density is not within the specified range. In step S10, the adjustment determination unit 44 controls each related apparatus parameter so that at least one of the line width, the film thickness, and the defect density is within the specified range. To determine whether it is adjustable. If adjustment is impossible in step S10 (NO), the etching process is stopped in step S11.

  If adjustment is possible in step S10 (YES), the adjustment control means 45 controls each related apparatus parameter in step S12, and the line width, film thickness, and defect density fall within the specified ranges. Adjust processing as follows. After the adjustment process, the process proceeds to a monitoring process of each related apparatus parameter in step S1.

  Here, the etching control apparatus 1 of Embodiment 1 and the etching control method using the same will be described in more detail. First, the plasma etching apparatus will be briefly described.

  FIG. 3 is a longitudinal sectional view schematically showing the plasma etching apparatus of the first embodiment.

In FIG. 3, the plasma etching apparatus 11 according to the first embodiment forms an upper electrode 14 by winding a coil 13 around the outer periphery of a dome-shaped member 12. A semiconductor wafer 16 is mounted on a stage 15 constituting the lower electrode. On the upper electrode 14 side between the upper electrode 14 and the semiconductor wafer 16 on the lower electrode, there is a gas introduction port for introducing four kinds of gases of Cl ₂ , HBr, O ₂ and CF ₄ into the chamber 17 here. A gas introduction pipe 18 is provided. The stage 15 constituting the lower electrode is supplied with He for cooling the back surface of the semiconductor wafer 16.

  With the above configuration, a predetermined RF power (high-frequency power W) is applied to the upper electrode 14, and a predetermined RF power is applied to the lower electrode that draws the gas plasma from the gas introduction pipe 18 generated in the upper electrode 14, Etching treatment is performed so that a portion of the semiconductor wafer 16 as a substrate on the stage 15, that is, a portion of the semiconductor wafer 16 on which a circuit pattern including at least one pattern region is formed, has a predetermined line width and a predetermined film thickness. Is done.

  Next, control of a gate etching process which is one of typical etching processes will be described.

  4 and 5 are vertical sectional views of the semiconductor device for explaining a typical gate etching process.

  As shown in FIG. 4, first, an element isolation layer 22 is formed on a semiconductor substrate 21 made of a silicon wafer or the like as a semiconductor wafer by a known method such as a LOCOS method or Shallow Trench Isolation (STI). A photoresist pattern is formed on the semiconductor substrate 21, and well formation is performed by ion implantation and heat treatment (not shown).

A gate oxide film 23 made of, for example, a SiO ₂ film or a SiON film is formed on the semiconductor substrate 21 by CVD or thermal oxidation, and a gate film 24 made of, for example, a polysilicon film (or metal) is further formed. Thereafter, a resist pattern 25 is formed on the gate film 24 by a known alignment method, and used for the plasma etching apparatus 11 (FIG. 3).

  Details of the control during the etching process by the plasma etching apparatus 11 will be described later. Thereafter, the remaining resist pattern 25 is removed by, for example, oxygen plasma, and then a reaction product adhering to the side wall of the gate pattern is removed by using a chemical such as hydrogen fluoride, as shown in FIG. Then, a gate electrode 24 a having a desired shape is formed at a predetermined position on the semiconductor substrate 21.

  It is measured whether the semiconductor substrate 21 after the formation of the gate electrode 24a has desired characteristics (for example, line width, film thickness, gate oxide film residual film, defect density, etc.).

  Thereafter, an ion implantation process or a heat treatment process is performed, and a silicon oxide film formed by, for example, BPSG or thermal oxidation is formed as an interlayer insulating film. After planarization by CMP or the like, the contact hole is formed by a known lithography method or dry process. A contact plug is formed by embedding a material such as tungsten by an etching method, and a metal wiring layer is formed on the upper portion thereof by using a material such as aluminum. Further, thereafter, a metal wiring layer required for the semiconductor product is formed by a known method through a via plug, and finally a connection window is formed on the uppermost metal wiring layer to obtain a semiconductor device (not shown). ).

  Next, a line width control method in the control of the gate etching process will be described.

  The apparatus parameters (process parameters) of the gate etching process are, for example, (1) pressure during processing, (2) gas type and supply amount (gas types are, for example, chlorine gas, hydrogen bromide gas, oxygen, 4 Fluorinated methane), (3) pressure of semiconductor substrate cooling gas (helium), (4) RF power, and (5) processing time.

  For example, gate etching conditions are as follows: pressure 60 mTorr (mTorr), chlorine flow rate 60 sccm, hydrogen bromide flow rate 100 sccm, oxygen flow rate 5 sccm, carbon tetrafluoride flow rate 25 sccm, cooling helium gas pressure 8 Torr (Torr), RF power (source electrode) ; For the conditions of upper electrode) 800W and (bias electrode; lower electrode) 80W, the etch shift value is calculated when each device parameter is changed independently, and the dependence of the etch shift value for each parameter is calculated. This is shown in FIG.

  For example, an etch shift model is extracted as a physical model or a statistical model from the relationship between all the apparatus parameters and the etch shift amount as follows.

Etch shift amount = k + α * pressure + β * chlorine flow rate + γ * hydrogen bromide flow rate + θ * oxygen flow rate + w * 4 fluorocarbon + x * cooling helium pressure + y * RF power (source electrode) + z * RF power (bias electrode)
Coefficients are calculated for k, α, β, γ, θ, w, x, y, and z, respectively.

  The specifications (allowable values) of the apparatus parameters during the etching process are calculated from the etch shift model calculated above, each coefficient, and the etch shift target.

  By inputting to the control device having the function of calculating the predicted value of the etch shift amount based on the etch shift model from the values extracted by the device parameters from the values calculated above, the semiconductor within the specified range of the specified specifications Substrate processing is performed. If processing exceeding the specification range is performed during processing, the processing is continued by stopping the etching process or changing each device parameter so that the etch shift value is within the specification (within the specified range). obtain.

  Further, the line width control method among the control items of the gate etching process will be described more specifically with reference to FIGS.

  FIG. 6 is a diagram for explaining an etch shift model for managing the etch shift amount for line width prediction, and showing the dependency of the vertical axis etch shift amount on each apparatus parameter on the horizontal axis. .

As shown in FIG. 6, the vertical axis represents the etch shift amount, and the horizontal axis represents the apparatus parameters of the etching apparatus. From the left, the pressure Pressure (mTorr) in the chamber and the four types introduced into the chamber (Cl ₂ , HBr) , O ₂ and CF ₄ ) gas flow rate (sccm), back surface cooling He pressure (Torr), upper electrode RF power (high frequency power W), lower electrode RF power (high frequency power W) for drawing plasma generated in the upper electrode It is.

  The etch shift amount corresponds to, for example, the line width after etching−the line width after photo when etching polysilicon (or metal) of the gate, and indicates how much the line width has changed by etching. Value. Since the line width after photo is known at the time of etching, it is the etch shift amount that is controlled by the etching apparatus, and what is the coefficient of the etch shift amount for each parameter of the etching apparatus? It is. In the relationship of the etch shift amount with respect to the eight kinds of parameters, what is at the center is a target to be controlled for each parameter. When individual parameters change on the etching apparatus side, it is possible to predict how much the line width after etching varies.

  A prediction formula (etch shift model) can be created by obtaining a coefficient from the relationship of the etch shift to these eight kinds of apparatus parameters.

Etch Shift Etch Shift = −19.3 + 0.772 × Pressure−0.539 × Cl 2 Flow + 0.0260 × HBr Flow −1.71 × O 2 Flow + 0.271 × CF 4 Flow + 0.0495 × Back−He +0.0215 SourcePower +0.447 × BiasPower
The amount of etch shift can be predicted using this prediction formula (etch shift model). For example, when the pressure target in the chamber is 5 mTorr, the etching process of the etching apparatus is stopped when the pressure target is 4 mTorr. In the first embodiment, when the pressure in the chamber is 4 mTorr, other parameters are included. Thus, it is possible to confirm what the etch shift will be. If the amount of etch shift is normal (within the specified range) in the confirmation result, it is not necessary to stop the etching process of the etching apparatus. Furthermore, other device parameters can be adjusted to obtain a predetermined line width. For example, when the pressure in the chamber is 4 mTorr, the gas flow rate of other apparatus parameters such as Cl ₂ is changed. As a result, a semiconductor wafer having a stable line width can be obtained, and yield and productivity can be improved.

  FIG. 7 is a diagram showing the relationship between the predicted value of the etch shift amount and the actual measurement value.

  As shown in FIG. 7, the prediction formula (etch shift model) is graphed, and the broken line in the horizontal direction in FIG. 7 indicates the center of the measured etch shift value. .3 ". When the predicted value of etch shift is “6.3”, the actually measured value of etch shift is also “6.3”. The predicted value of the etch shift and the actually measured value coincide with each other at the center of the etch shift, but the predicted value and the actually measured value of the etch shift are dispersed as the distance from the center increases. The range of the variation is within the specified range and is indicated by a one-dot chain line. For example, when the predicted value of etch shift is “0”, that is, when the line width after etching−the line width after photo is “0”, the measured value of etch shift is within the range of the one-dot chain line including “0”. It varies.

  FIG. 8 is a diagram for explaining an etch rate model for managing the etch amount for predicting the film thickness, and showing the dependence of the etch rate amount on the vertical axis with respect to the apparatus parameters on the horizontal axis.

As shown in FIG. 8, the vertical axis represents the etch rate amount, and the horizontal axis represents the etching apparatus parameters from the left, the pressure Pressure (mTorr) in the chamber and the four types (Cl ₂ , HBr, O ₂ and CF ₄ ) gas flow rate (sccm), upper electrode RF power Ws (high frequency power W), lower electrode RF power Wb (high frequency power W) for drawing plasma generated in the upper electrode, He pressure (Torr for back surface cooling) ).

  The amount of etch rate is the amount of etch for obtaining the desired residual film thickness after etching, for example when etching polysilicon or metal of the gate, and unit etching indicating how much film thickness is obtained by etching Amount. It is necessary to know how much the etching rate amount is for each apparatus parameter of the etching apparatus. In the relationship of the etching rate amount with respect to the eight kinds of parameters, what is at the center is a target to be controlled for each apparatus parameter. When the individual apparatus parameters change on the etching apparatus side, it is possible to predict how much the amount of etch rate after etching varies.

  A prediction formula (etch rate model) can be created by obtaining a coefficient from the relationship of the etching amount with respect to these eight kinds of apparatus parameters.

Etch Rate Etch Rate = 485 + 32.5 × Pressure + 6.89 × Cl2Flow−3.15 × HBrFlow + 13.8 × O2FLow + 8.25 × CF4Flow−5.00 × Back−He + 1.17 SourcePower + 8.86 × BiasP
The amount of etch can be predicted using this prediction formula (etch rate model). For example, when the target of the pressure in the chamber is 6.3 mTorr, the etching process of the etching apparatus stops conventionally when the pressure becomes 4 mTorr. In the first embodiment, when the pressure in the chamber is 4 mTorr, other parameters It is possible to check the etching amount including the above, and if the etching amount is normal, there is no need to stop the etching apparatus. Further, other parameters can be adjusted to obtain a predetermined film thickness. For example, when the pressure in the chamber is 4 mTorr, the gas flow rate of another parameter such as Cl ₂ is changed. Thus, productivity can be improved with a semiconductor wafer having a stable film thickness.

  FIG. 9 is a diagram showing the relationship between the predicted value of the etch amount and the actual measurement value.

  As shown in FIG. 9, the prediction formula (etch rate model) is graphed, and the broken line in the horizontal direction in FIG. 9 indicates the center position of the actual measurement value, and the unit etch amount (etch rate amount) at this time The actual measurement value is “2673”. When the predicted value of the etch amount is “2673”, the actually measured value of the etch amount is also substantially “2673”. The predicted value and measured value of the unit etch amount (etch rate amount) match the closer to the center position, but the predicted value and measured value of the unit etch amount (etch rate amount) disperse as the distance from the center increases. The prescribed range of the variation is indicated by a one-dot chain line.

  FIG. 10 is a diagram for explaining a defect number model for managing the number of particles for predicting the number of defects, and is a diagram illustrating the number of particles per wafer with respect to the cumulative number of processed sheets in the etching apparatus.

  As shown in FIG. 10, since a film adheres to the periphery of the apparatus and increases cumulatively, the number of particles per wafer rises exponentially with respect to the cumulative number of substrates processed by the etching apparatus. . In the feature quantity specification, the number of particles per wafer is 15 or less. In this case, it is necessary to set the number of substrates accumulated in the etching apparatus to 800 or less as an apparatus parameter.

  As described above, according to the first embodiment, the parameter extraction means 41 for extracting the current state of the apparatus parameters indicating the apparatus operating conditions such as pressure and gas flow rate, the line width indicating the apparatus processing result from the current state of the apparatus parameters, And a continuation determining unit 43 that includes a feature amount calculating unit 42 that calculates a feature amount such as a film thickness, and a continuation determining unit 43 that determines whether to continue the processing of the apparatus depending on whether the calculated feature amount is within a specified range. Performs a predetermined process when it is determined that the processing of the apparatus is to be continued, and stops the predetermined process when the continuation determination unit 43 determines not to continue the process of the apparatus.

  Also, if the continuation determination unit 43 determines not to continue the processing of the device, whether or not the feature amount falls within the specified range by controlling the related device parameters instead of immediately stopping the predetermined processing If the adjustment is impossible, the adjustment determination means 44 for stopping the predetermined processing, and if the adjustment is possible, the related apparatus parameter is controlled to control the feature amount. Adjustment control means 45 which performs adjustment processing so that the value falls within the specified range and shifts to processing by the parameter extraction means.

  As described above, the continuation determination unit 43 determines whether or not to continue the processing of the device depending on whether or not the feature amount calculated from the device parameters in the current state by the feature amount calculation unit 42 is within the specified range, or the adjustment control unit 45. However, since the adjustment processing is performed so that the related apparatus parameters are controlled and the feature amount falls within the specified range, it is possible to improve the yield and the productivity in the manufacture of semiconductor products. In this case, the target value of the apparatus parameter for the etching process can be set from the feature amount of the substrate.

  In short, since the etching equipment can be controlled from the process characteristic values and defect density values of each process, which are closely related to the substrate yield, the optimum specifications for each parameter can be set in terms of productivity and yield. It becomes possible. For this reason, it becomes possible to produce without waste corresponding to improvement in yield of semiconductor devices and shortening of delivery time.

  Although not specifically described in the first embodiment, in the etching control method in the manufacture of semiconductor products, the change of the apparatus parameter (process parameter) indicates a process trend indicating the relationship between the feature quantity of the semiconductor substrate and the process parameter. It may be performed based on data. In this way, the process parameter can be appropriately changed based on such data.

  Although not particularly described in the first embodiment, in the etching control method in manufacturing a semiconductor product, the apparatus parameters (process parameters) include high-frequency power applied to the chamber, pressure in the chamber, and introduction into the chamber. And / or a distance between electrodes arranged in the chamber so as to sandwich the semiconductor substrate. When the processing state of the semiconductor substrate is not appropriate, the processing state is corrected by changing the above-described process parameters, and as a result, a semiconductor product having a desired processing result and desired characteristics can be efficiently obtained.

  Although not specifically described in the first embodiment, in the etching control method, the feature amount of the semiconductor substrate includes at least one of the line width, the film thickness, and the defect density on the semiconductor substrate. May be a feature. In the etching process, the above apparatus parameters can be calculated based on the current signal and the voltage signal monitored during the process. Therefore, it is possible to determine whether or not the etching process is appropriate based on whether or not the feature amount calculated from the apparatus parameters is within a specified range, and accordingly, an appropriate action can be taken during the process on the semiconductor substrate. As a result, it is possible to improve the yield of semiconductor products.

  Although not particularly described in the first embodiment, the etching control method in manufacturing a semiconductor product is an apparatus for effectively implementing the above-described etching control method in manufacturing a semiconductor product according to the present invention.

  That is, an etching control method in the manufacture of a semiconductor product includes a step of extracting device parameters of a substrate etching process for a semiconductor substrate on which a circuit pattern composed of at least one pattern region is formed, and a substrate from the device parameters of each etching step. The step of calculating the feature amount for each and the processing of the device is continued by changing at least one of the processing time and the device parameter based on the calculated target value of the feature amount, or the calculated feature amount for each substrate is And a step of stopping the processing of the apparatus when it is outside the set specified range.

  As described in the first embodiment, the feature amount for each substrate in the method for controlling an etching apparatus in the manufacture of a semiconductor product according to the present invention is calculated using a physical model or a statistical model from the apparatus parameters of each etching process of the substrate. It is characterized by using.

  In the first embodiment, the substrate processing control apparatus and the substrate processing control method of the present invention are applied to the etching control apparatus and the etching control method for the etching process using the plasma etching apparatus 11, but the present invention is not limited thereto. 4 and 5, the substrate processing control apparatus and the substrate processing control method according to the present invention are performed using the apparatus parameters as the oxygen flow rate, the chamber temperature and the chamber pressure, and the characteristic amount as the film thickness. The present invention can also be applied to a thin film formation control device and a thin film formation control method.

  As mentioned above, although this invention has been illustrated using preferable Embodiment 1 of this invention, this invention should not be limited and limited to this Embodiment 1. It is understood that the scope of the present invention should be construed only by the claims. It is understood that those skilled in the art can implement an equivalent range from the description of the specific preferred embodiment 1 of the present invention based on the description of the present invention and the common general technical knowledge. Patents, patent applications, and documents cited herein should be incorporated by reference in their entirety, as if the contents themselves were specifically described herein. Understood.

  The present invention relates to a substrate processing control apparatus and a substrate processing control method for etching processing in the manufacture of semiconductor products, a control program in which processing procedures for causing a computer to execute each step of the substrate processing control method are described, and the control program In the field of computer-readable readable storage media in which is stored, whether or not the continuation determination unit continues the processing of the device depending on whether or not the feature amount calculated by the feature amount calculation unit from the device parameters in the current state is within a specified range. Judgment or the adjustment control means controls the related apparatus parameters to perform adjustment processing so that the feature amount falls within the specified range, so that the yield and productivity in the manufacture of the semiconductor device can be improved.

1 Etching control device (substrate processing control device)
2 Operation input unit 3 Display unit 4 CPU (control unit)
41 parameter extraction means 42 feature quantity calculation means 43 continuation judgment means 44 adjustment judgment means 45 adjustment control means 5 RAM (temporary storage means)
6 ROM (readable recording medium)
DESCRIPTION OF SYMBOLS 11 Plasma etching apparatus 12 Dome-shaped member 13 Coil 14 Upper electrode 15 Stage 16 Semiconductor wafer (substrate)
17 chamber 18 gas introduction pipe 21 semiconductor substrate 22 element isolation layer 23 gate oxide film 24 gate film 24a gate electrode 25 resist pattern

Claims (16)

Parameter extracting means for extracting the current state of the device parameter indicating the device operating condition, feature amount calculating means for calculating the feature amount indicating the device processing result from the current state of the device parameter, and the feature calculated by the feature amount calculating means Continuation determination means for determining whether or not to continue the processing of the apparatus depending on whether the amount is within a specified range, and when the continuation determination means determines to continue the processing of the apparatus, performs a predetermined substrate processing,
If the continuation determining means determines that the processing of the apparatus is not continued, the feature amount is within the specified range by controlling the related apparatus parameters instead of immediately stopping the processing of the predetermined substrate. If the adjustment is impossible, the adjustment determination means for stopping the processing of the predetermined substrate and, if the adjustment is possible, control the related apparatus parameters. Then, the substrate processing control apparatus includes an adjustment control unit that performs an adjustment process so that the feature amount falls within the specified range and shifts to a process by the parameter extraction unit . The substrate processing control apparatus according to claim 1, wherein the adjustment control unit sets a target value of the apparatus parameter from the feature amount of the predetermined substrate .   The apparatus parameters include the pressure in the chamber of the apparatus, the gas flow rate introduced into the chamber, the gas pressure for cooling the substrate back surface, the upper electrode RF power, and the lower electrode RF for drawing the plasma generated in the upper electrode. The substrate processing control apparatus according to claim 1, comprising at least one of power, temperature in the chamber, processing time, and the number of processed substrates.   The substrate processing control apparatus according to claim 1, wherein the feature amount includes at least one of a line width, a film thickness, and a defect density of a circuit pattern formed on the substrate.   The substrate processing control apparatus according to claim 1, wherein the feature amount is calculated from the apparatus parameter using a physical model or a statistical model. The apparatus parameters include pressure Pressure (mTorr) in the chamber, gas flow rates (sccm) of four types (Cl ₂ Flow, HBrFlow, O ₂ FLow and CF ₄ Flow) introduced into the chamber, Back-Heating Back-He Pressure (Torr), upper electrode RF power (SourcePowerW), and lower electrode RF power (BiasPowerW) that draws plasma generated in the upper electrode, and the physical model or The prediction formula of the etch shift model as a statistical model
Etch Shift Etch Shift = −19.3 + 0.772 × Pressure−0.539 × Cl 2 Flow + 0.0260 × HBr Flow −1.71 × O 2 Flow + 0.271 × CF 4 Flow + 0.0495 × Back−He +0.0215 SourcePower +0.447 × BiasPower
The substrate processing control apparatus according to claim 5. The apparatus parameters include pressure Pressure (mTorr) in the chamber, gas flow rates (sccm) of four types (Cl ₂ Flow, HBrFlow, O ₂ FLow and CF ₄ Flow) introduced into the chamber, Back-Heating Back-He Pressure (Torr), upper electrode RF power (SourcePowerW), and lower electrode RF power (BiasPowerW) that draws plasma generated in the upper electrode. The prediction formula of the etch rate model as a statistical model
Etch Rate Etch Rate = 485 + 32.5 × Pressure + 6.89 × Cl2Flow−3.15 × HBrFlow + 13.8 × O2FLow + 8.25 × CF4Flow−5.00 × Back−He + 1.17 SourcePower + 8.86 × BiasP
The substrate processing control apparatus according to claim 5. A parameter extraction step in which the parameter extraction means extracts the current state of the device parameter indicating the device operating condition, and a feature amount calculation step in which the feature amount calculation means calculates a feature amount indicating the device processing result from the current state of the device parameter. And a continuation determination step for determining whether or not to continue the processing of the device depending on whether or not the feature amount calculated in the feature amount calculation step is within a specified range, and the processing of the device in the continuation determination step If it is determined to continue, the predetermined substrate is processed,
If it is determined in the continuation determination step that the processing of the apparatus is not continued, the adjustment determination means does not stop the processing of the predetermined substrate immediately, but the adjustment determination means controls the related apparatus parameters to determine the feature amount. It is determined whether or not adjustment within the specified range is possible. If the adjustment is impossible, an adjustment determination process for stopping the processing of the predetermined substrate; and adjustment control if the adjustment is possible. A substrate processing control method comprising: an adjustment control step in which means controls the related apparatus parameters to perform adjustment processing so that the feature amount falls within the specified range, and shifts to processing by the parameter extraction step . The substrate processing control method according to claim 8, wherein the adjustment control unit sets a target value of the apparatus parameter from the feature amount of the predetermined substrate .   The apparatus parameters include the pressure in the chamber of the apparatus, the gas flow rate introduced into the chamber, the gas pressure for cooling the substrate back surface, the upper electrode RF power, and the lower electrode RF for drawing the plasma generated in the upper electrode. The substrate processing control method according to claim 8, comprising at least one of power, temperature in the chamber, processing time, and number of processed substrates.   The substrate processing control method according to claim 8, wherein the feature amount includes at least one of a line width, a film thickness, and a defect density of a circuit pattern formed on the substrate.   The substrate processing control method according to claim 8, wherein the feature amount is calculated from the apparatus parameter using a physical model or a statistical model. The apparatus parameters include pressure Pressure (mTorr) in the chamber, gas flow rates (sccm) of four types (Cl ₂ Flow, HBrFlow, O ₂ FLow and CF ₄ Flow) introduced into the chamber, Back-Heating Back-He Pressure (Torr), upper electrode RF power (SourcePowerW), and lower electrode RF power (BiasPowerW) that draws plasma generated in the upper electrode. The coefficient is obtained from the relationship between the etch shift amount with respect to the apparatus parameter, and the physical model or the The prediction formula of the etch shift model as a statistical model
Etch Shift Etch Shift = −19.3 + 0.772 × Pressure−0.539 × Cl 2 Flow + 0.0260 × HBr Flow −1.71 × O 2 Flow + 0.271 × CF 4 Flow + 0.0495 × Back−He +0.0215 SourcePower +0.447 × BiasPower
The substrate processing control method according to claim 12. The apparatus parameters include pressure Pressure (mTorr) in the chamber, gas flow rates (sccm) of four types (Cl ₂ Flow, HBrFlow, O ₂ FLow and CF ₄ Flow) introduced into the chamber, Back-Heating Back-He Pressure (Torr), upper electrode RF power (SourcePowerW), and lower electrode RF power (BiasPowerW) that draws plasma generated in the upper electrode. The prediction formula of the etch rate model as a model
Etch Rate Etch Rate = 485 + 32.5 × Pressure + 6.89 × Cl2Flow−3.15 × HBrFlow + 13.8 × O2FLow + 8.25 × CF4Flow−5.00 × Back−He + 1.17 SourcePower + 8.86 × BiasP
The substrate processing control method according to claim 12.   15. A control program in which a processing procedure for causing a computer to execute each step of the substrate processing control method according to claim 8 is described.   A computer-readable storage medium in which the control program according to claim 15 is stored.

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