JP4324545B2 - Etching processing apparatus and processing method - Google Patents

Description

  The present invention relates to an etching processing apparatus and an etching processing method, and more particularly to an etching processing apparatus and an etching processing method capable of suppressing the influence of disturbance.

  An etching processing apparatus using plasma, for example, introduces an etching gas into a vacuum processing chamber, generates a plasma discharge under reduced pressure, guides radicals or ions generated in the plasma to the surface of the wafer that is the object to be processed, The wafer surface is etched by reacting on the wafer surface. An etching processing apparatus that performs such processing (dry processing) performs etching processing based on manufacturing conditions (gas flow rate, gas pressure, input power, etching time, etc.) called a preset recipe.

  The recipe includes, for example, a manufacturing process (single film to be etched) consisting of a specific process of a semiconductor device except for a photomask manufacturing process in which one process is divided into several steps and manufacturing conditions are changed for each step. In the etching process step, it is usually kept constant.

  However, even if a certain etching process using a certain recipe is performed, it is difficult to always obtain a certain performance due to various disturbances such as aging of the apparatus.

Therefore, as a method for suppressing disturbance, for example, Patent Document 1 discloses a method of monitoring a processing result and feeding back to a recipe based on the monitoring result.
JP 2003-17471 A

  When a processing result for a sample such as a semiconductor wafer is monitored and the monitoring result is fed back to a recipe, the recipe includes many parameters such as gas flow rate, pressure, input power, and etching time. Of these parameters, it is necessary to perform a great number of experiments and simulations with a great deal of labor and time in order to identify optimal parameters for control and to build a control model using the specified parameters. Become.

  Even if the optimal control model is constructed, unexpected side effects may occur. For example, in a gate etching process for forming a gate electrode of an FET (Field Effect Transistor), since it does not affect device performance, an etching process that does not impede the thin gate insulating film directly under the film to be etched is required. . However, as a result of feeding back the monitoring results to the recipe as described above, if the characteristics of the device fluctuate in the direction in which the selection ratio between the film to be etched and the gate insulating film deteriorates, the gate insulating film will be processed. This will damage the gate insulating film.

  That is, even if it is assumed that various disturbances are suppressed by feedback control, a great amount of labor and time are required to realize it in an actual manufacturing process, and further, the concern about unexpected side effects cannot be wiped out. The present invention has been made in view of these problems. In particular, when performing feedback control, it is possible to reduce concerns about unexpected side effects, and to build a control model without taking much effort and time. An etching method is provided.

  In order to solve the above problems, the present invention employs the following means.

An etching processing apparatus for performing an etching process including a plurality of etching steps each applying a different recipe to a single film to be etched on a gate insulating film ,
A plasma state in the etching processing chamber is monitored, a processing result estimation unit that estimates an etching processing result based on the monitored result, and a control model unit that adjusts a recipe based on the estimated etching processing result, A recipe to be applied to an etching step in which the underlying layer in contact with the film to be etched may be exposed among the plurality of etching steps is fixed to a preset recipe, and one of the remaining etching steps among the plurality of etching steps. Etching is performed based on the recipe adjusted by the control model unit.

  Since the present invention has the above-described configuration, it is possible to reduce anxiety about an unexpected side effect when performing feedback control, and an etching processing apparatus and method capable of constructing a control model without taking much labor and time. Can be provided.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a diagram showing an etching processing apparatus according to an embodiment of the present invention. In the figure, a main body 300 of an etching processing apparatus includes a processing chamber (processing vessel) 201, gas supply means 202 for supplying a processing gas into the processing chamber, and gas exhaust for controlling the pressure in the processing chamber by exhausting the processing gas. Means 203 are provided. Further, a sample stage 205 that supports a sample 204 to be processed is installed in the processing chamber 201, and plasma generating means 206 for generating plasma is provided in the processing chamber.

  The plasma generation means includes an electromagnetic wave supply means 301 that transmits and supplies an electromagnetic wave into the treatment chamber 201, and solenoid coils 302 and 303 for generating a magnetic field in the processing chamber 201. In addition, a high frequency voltage is applied to the sample stage 205 from a high frequency power supply 304 in order to direct reactants generated by the generated plasma to the sample side.

  In this dry etching apparatus, apparatus state detection means 208 is installed. The apparatus state detection unit 208 includes, for example, a monitor that detects the flow rate of the gas supplied from the gas supply unit 202, a detector that detects the current and voltage of a power supply path that supplies power for plasma generation, and the current and voltage It comprises a detector for detecting a phase difference, a detector for detecting a traveling wave and a reflected wave of high-frequency power supplied for plasma generation, an impedance monitor, and the like.

  The apparatus state detection unit 208 includes an analyzer that detects light emitted from the plasma generated by the plasma generation unit 206 in the processing chamber 201 and analyzes it. The apparatus state detection means 208 is preferably a detector that outputs a large number of signals, such as a spectrometer that outputs a wavelength-resolved emission spectrum, but is a detector that extracts light of a single wavelength, such as a monochromator. Also good. The emission spectrum of the output of the spectrometer is a signal representing the light intensity for each wavelength. The apparatus state detection means 208 may be a general plasma state monitor such as a quadrupole mass analyzer that outputs a mass spectrum of a substance in plasma.

  Further, in the present embodiment, a control device 209 that receives the output from the device state detection means 208 and adjusts the operation of the device is provided. The control device 209 performs, for example, on and off of the input power to the plasma generating unit 206 including a magnetron that generates an electromagnetic wave or a magnetic field for generating plasma, or adjusts the input power. In addition, the output of plasma generated using other means can be adjusted. For example, the apparatus state detection means 208 may increase / decrease a specific reaction amount related to processing based on detection data obtained by detecting light having a predetermined wavelength generated while processing a sample using plasma, reaction rate, and plasma. By detecting a reaction state such as strength, it is possible to adjust the operation of the apparatus by issuing commands to generate / stop plasma and to start / stop the apparatus.

  Further, the control device 209 can adjust the operation of the processing apparatus in response to an output from the inspection apparatus 210 that is installed separately or integrated with the etching processing apparatus. The inspection apparatus 210 is generally a CD-SEM (scanning electron microscope) that measures a processed shape after etching, for example, but an optical processed shape measuring means called scatterometry using scattered light. But it ’s okay.

  FIG. 2 is a diagram schematically showing a gate electrode formation process in each semiconductor step in a semiconductor device to be processed by the etching processing apparatus according to the present embodiment. In the figure, reference numeral 110 denotes a wafer provided with a silicon substrate 111, a gate insulating film 112, and a polycrystalline silicon film 113 as a single film to be etched. The wafer is provided with a mask 114, and on the wafer surface. A natural oxide film 115 is formed.

  Next, the etching process will be described with reference to FIG. First, in step 1, a wafer 110 on which a mask 104 is formed is prepared. Since a natural oxide film is formed on the surface of the polysilicon 113 not covered with the mask 104, it is removed (breakthrough) in step 2. In step 3, a recipe that can maintain a high etching rate is adopted and etching is performed with a good shape (main etching 1). In step 4, a recipe capable of maintaining the selection ratio with the gate insulating film is adopted and processed so as not to affect the gate insulating film (main etching 2). In step 5, the residue of the film to be etched is removed by etching (overetching).

  In the etching process, “main etching” indicates a step of etching the film to be etched, a step of removing a material on the surface of the film to be etched such as a natural oxide film (breakthrough) and a residue of the film to be etched are removed. The process except a step (overetching) is shown.

  Incidentally, the gate length 200 shown in FIG. 2 is becoming shorter year by year in order to increase the device speed and power consumption. Since the gate length of a device is an important dimension that determines the characteristics of the device, it is called a CD (Critical Dimension) value. As the gate length becomes shorter, the variation in the gate length allowed in the gate etching process is on the order of several nanometers, and an etching process that can stably manufacture the gate length is increasingly required. In addition, as the gate length becomes finer, the gate insulating film is becoming thinner. For example, when the gate length is 100 nm, the thickness of the gate insulating film is about 2 nm. For such a gate insulating film, an etching process that does not damage the gate insulating film is required in order to avoid deterioration of the insulating characteristics of the gate insulating film.

  In general, dry etching equipment uses manufacturing conditions (gas flow rate, gas pressure, input power, etching time, etc.) called a recipe before manufacturing (mass production) so that the required dimensions and shape of the workpiece (sample) to be processed can be satisfied. ). As described above, except for the photomask manufacturing process, the recipe is usually kept constant during the manufacturing (mass production). However, even if the etching process is performed using a certain recipe as described above, it is difficult to always obtain a certain etching result due to various disturbances such as a change with time of the apparatus.

  FIG. 3 is a diagram for explaining the processing of the etching processing apparatus according to the present embodiment. In the figure, reference numeral 1 denotes a plasma etching processing chamber for generating plasma 1c, and reference numeral 1b denotes a wafer which is an object to be processed placed on a wafer stage 1a in the processing chamber. Reference numeral 2 denotes a sensor for monitoring a process amount during processing such as a flow rate of gas supplied to the apparatus, pressure, input power, and the like, and these sensors are usually provided as standard equipment in a plasma etching processing apparatus. Reference numeral 3 denotes an additional sensor, for example, an emission spectroscopy sensor (OES) for monitoring the spectrum of plasma light, a quadrupole mass spectrometer (QMS) for analyzing the mass in the plasma. ) Etc. Reference numeral 4 denotes an actuator for controlling the etching processing apparatus according to the recipe 5. Reference numeral 6 denotes a control model unit that calculates the recipe 5 based on the processing result obtained from the inspection apparatus 8, and this recipe can be changed for each wafer process or during the process.

  The inspection device 7 is generally a CD-SEM, but it is also a scatterometry (light scattering type shape measuring means) that measures the size and shape using light scattered light separately from the etching processing device. good. Moreover, this apparatus may be integrated with the etching processing apparatus.

  The wafer 8 supplied from the previous process is supplied to the plasma etching processing chamber 1. The supplied wafer is processed in units of a plurality of lots to become an etched wafer 9. The wafer 9 is supplied to an inspection apparatus 7 such as a CD-SEM in order to inspect the etching (processing) result. The inspected wafer 10 is transferred to the next process.

  The result (CD value) inspected by the inspection device 7 calculates a deviation from the target value, and is output to the control model unit 6. The control model unit 6 calculates a recipe for the next processing wafer using substantially the same process on the basis of the CD value control model 11 that has been constructed in advance through experiments or simulations, and starts the next etching using the recipe. Is done.

  What is concerned about such feedback control is the side effect of the control described above. That is, the gate etching process requires an etching process that does not damage the thin gate insulating film under the film to be etched. However, when the control including the adjustment of the recipe as described above is performed, the selection ratio between the film to be etched and the gate insulating film may fluctuate, and in this case, even the gate insulating film is processed. A side effect occurs.

FIG. 4 is a diagram showing the CD value controllability with respect to the oxygen O ₂ flow rate in the main etching 1. As shown in the figure, linear controllability is shown, and it is understood that the flow rate control of oxygen O ₂ in the main etching 1 is an effective control parameter for the CD value control. Further, in the main etching 1, since the gate insulating film is not exposed during the etching, it is not necessary to consider the side effect on the gate insulating film. In the example of FIG. 4, the control factor and the result are in a linear relationship, but the present invention can also be applied when this relationship is not linear.

That is, in the etching process control for always obtaining a constant result with respect to various disturbances, the gate insulating film such as the main etching 2 and the over-etching can be controlled so as not to damage the gate insulating film. The recipe of the step that may be exposed is fixed, and at least one parameter in the step where the gate insulating film such as breakthrough or main etching 1 is not exposed (there is no risk of exposure) is targeted, and at least one parameter in the step Is used as a variable parameter to perform feedback control (recipe adjustment). For example, when oxygen O ₂ is used as the control parameter as described above, a recipe other than oxygen O _{2 of} main etching 1 (ME1) is fixed and only the flow rate of oxygen O ₂ is variable as shown in FIG. And

FIG. 6 is a diagram for explaining a CD value control mechanism when the flow rate of oxygen O 2 is changed in the main etching 1. When the flow rate of oxygen O _{2 in} the main etching process 1 (etching on the upper layer portion of the film to be etched, ME1) is increased, deposition on the side wall of the material to be etched increases, and a side wall protective film is formed. For this reason, the gate dimension (CD value) formed after the completion of the main etching process is formed to be thicker by several nm than before the increase in the flow rate of oxygen O ₂ . In contrast to the above, the CD value can be reduced by reducing the flow rate of oxygen O ₂ .

  Next, during the main etching process 2 (etching of the lower layer portion of the film to be etched, ME2), the side wall protective film formed when the main etching process 1 is completed acts. For this reason, the initial size and shape in the main etching process 2 inherit the dimensions and shape at the time of completion of the main etching process 1, and as a result, the CD value is formed thick by several nm.

  The important part (CD value) as the gate length that affects the characteristics of the device is the dimension of the lowermost part (hem part) of the etched polysilicon layer, so it is important to process the dimension of this part stably. is there.

Here, what is important is that the flow rate of oxygen O ₂ as a variable parameter cannot be varied indefinitely. For example, when the CD value of the previous etching is about 10 nm thinner than the target value, the required oxygen O ₂ flow rate is calculated based on the CD controllability with respect to the oxygen O ₂ flow rate shown in FIG. Exceeds the preset control range of the variable parameter (excess control). In this case, the flow rate of oxygen O ₂ cannot be increased accordingly. This is because if oxygen O ₂ is increased too much, another side effect that causes a problem in device performance may occur. Therefore, when the flow rate of oxygen O ₂ is set as a variable parameter, an upper limit and a lower limit are set in advance, and when the flow rate of oxygen O ₂ exceeds the value during recipe calculation, an alarm is output or the etching process is stopped. Alternatively, it is necessary to take measures such as executing the flow rate at the upper limit value or the lower limit value.

In this embodiment, oxygen O ₂ is selected as a variable parameter. As the variable parameter, the etching time, the RF or pulse bias power applied to the substrate to be processed, the etching gas flow ratio (Cl ₂ / (HBr + Cl ₂ )) ), Gas flow rates of additive gases such as N ₂ can be employed. When the etching time is a variable parameter, a difference in initial film thickness can be absorbed by using a film thickness monitor that monitors the film thickness during processing. Further, in a highly accurate etching process that is an object of the present invention, it is desirable to devise a method for keeping the processing film thicknesses of all steps at a set value by a film thickness monitor. Even when these variable parameters are controlled, it is important to set a variable parameter variable range in order to cope with excessive control.

  FIG. 7 is a view for explaining a modification of the etching processing apparatus according to the present embodiment. In the figure, the same parts as those shown in FIG. 3 are denoted by the same reference numerals and description thereof is omitted. It is known that the processing result by the etching process is closely related to the processing chamber environment during the etching process. Therefore, the state in the processing chamber can be monitored by the sensor 2 or the additional sensor 3, and the machining result estimation unit 20 can estimate the machining state based on this state. For the estimation of the machining state, a prediction model 21 constructed based on the results of experiments and simulations in advance is used.

  After the model is constructed, it is stored in the processing result estimation unit, and further corrected based on the measurement value from the inspection device 7 that inspects the etching process result. Thereby, the model accuracy can be improved.

  In addition, the control model unit 6 adjusts the recipe of wafers of the same or substantially the same type to be processed next based on the deviation between the processing result estimated as described above and the target value of the processing dimension of the process. . At this time, the parameter to be adjusted is limited to the parameter of the etching step that does not affect the gate insulating film. Note that the control model 6 confirms controllability as shown in FIG. 4, for example, in advance by experiments and simulations, and constructs a control algorithm.

  FIG. 8 is a diagram illustrating an example of a CD value control flow. In this example, in the etching processing apparatus shown in FIG. 7, the control flow of the CD value when the emission spectral sensor OES is used as the additional sensor 3 is shown. Hereinafter, each step will be described. First, in step 1, the natural oxide film formed on the surface of the film to be etched is removed (breakthrough). During a predetermined period in this step, the plasma emission spectrum is collected using the emission spectral sensor OES. In step 2, the current apparatus state is grasped using the emission spectrum data, the processing result in the current apparatus is predicted, and the recipe used in step 4 is changed based on the prediction result.

  Specifically, several index values as representative values of the process state monitor in step 1 are calculated immediately using the multivariate analysis or a specific filter for the collected spectrum. Next, the etching processing result is estimated from the calculated index value based on the correlation between the index value prepared in advance and the CD value as the final processing result. The advantage of this method is that the control method used so far can only process a sample, measure the deviation from the reference value of the processing shape from the result, and stabilize the subsequent processing of the sample. In this case, the time delay required for the control is large, and there are many samples that are not corrected by the control. Furthermore, if some device fluctuation occurs while the control is delayed, the control itself may be meaningless.

  However, if the method shown in FIG. 8 is used, it is possible to monitor the processing state of the sample to be controlled and perform stable control with very high accuracy in order to calculate the control amount therefrom.

In step 3, based on the processing result estimated in step 2, at least one parameter (variable parameter) of the recipe used in step 4 is adjusted so that the etching processing result becomes a target value. At this time, if the preset adjustment range of the parameter is exceeded, the closest value within the adjustment range is set or the process is interrupted, and an alarm is output to the apparatus user in some form. As variable parameters, in addition to the flow rate of oxygen O ₂ , etching time, RF or pulse bias power applied to the substrate to be processed, etching gas flow rate ratio (Cl ₂ / (HBr + Cl ₂ )), N _2, etc. The gas flow rate of the additive gas can be employed. When the etching time is a variable parameter, a difference in initial film thickness can be absorbed by using a film thickness monitor that monitors the film thickness during processing.

  In step 4, the film to be etched is etched using the recipe calculated in step 3. In step 5, the etching target film is etched using a recipe having a high selection ratio with respect to the gate insulating film until the gate insulating film is exposed. In step 6, finishing etching (over-etching) is performed on the residue that could not be etched in step 5 using a recipe with a margin that does not cause damage to the gate insulating film. Although FIG. 8 tries to detect the change in the processing state in the breakthrough processing state, the breakthrough step is often short and unstable, and the processing state fluctuation may not be detected well.

  FIG. 9 is a diagram showing an example of another CD value control flow for coping with this problem. First, in step 10, the natural oxide film formed on the surface of the film to be etched is removed (breakthrough). In step 11, the film to be etched is etched. During the predetermined period of this step, the plasma emission spectrum is collected using the emission spectral sensor OES. In step 12, the current apparatus state is grasped using the emission spectral data acquired in step 11, the processing result in the current apparatus state is predicted, and the recipe in step 14 is changed.

  Specifically, several index values as representative values of the process state monitor in step 11 are calculated using the collected spectrum immediately using multivariate analysis or a specific filter. Next, the etching processing result is estimated from the calculated index value based on the correlation between the index value prepared in advance and the CD value as the final processing result.

  In step 13, based on the processing result estimated in step 12, at least one parameter (variable parameter) of the recipe in step 14 is adjusted so that the etching processing result becomes a target value. At this time, if the preset adjustment range of the parameter is exceeded, the closest value within the adjustment range is set or the process is interrupted, and an alarm is output to the apparatus user in some form.

As variable parameters, in addition to the flow rate of oxygen O ₂ , etching time, RF or pulse bias power applied to the substrate to be processed, etching gas flow rate ratio (Cl ₂ / (HBr + Cl ₂ )), N _2, etc. The gas flow rate of the additive gas can be employed. When the etching time is a variable parameter, a difference in initial film thickness can be absorbed by using a film thickness monitor that monitors the film thickness during processing. In step 14, the film to be etched is etched using the recipe calculated in step 13. In step 15, the film to be etched is etched with a recipe having a high selectivity with respect to the gate insulating film until the gate insulating film is exposed. In step 16, finishing etching (over-etching) is performed on the residue that could not be etched in step 15 by a recipe with a margin that does not cause damage to the gate insulating film.

FIG. 10 is a diagram for explaining the factors determining the gate length in the etching process. In the figure, processing is performed in the order shown in Step 1, Step 2, and Step 3 of FIG. 10, and the etching processing of the present invention is performed in the order shown in Step 1 and Step 2 of Step 3. In the drawings showing these steps, reference numeral 110 denotes a wafer including a silicon substrate 111, a gate insulating film 112, and a polycrystalline silicon film 113, and the wafer is a hard mask material made of SiO ₂ or the like on the surface. A layer 114 ′ is provided, and a resist mask 201 is formed on the hard mask material layer 114 ′. Step 1 is a photolithography step in the semiconductor manufacturing process, and shows a state in which the resist mask 201 is formed. Step 2 shows a step of forming the hard mask 114 by etching the hard mask material layer 114 ′ mainly using an insulating film etching apparatus in the etching step in the semiconductor manufacturing process. The hard mask 114 serves as a mask for etching the gate material 113 made of a polycrystalline silicon film, and is one factor that determines the final gate size. Note that the resist mask 201 is removed after the completion of this step.

  Step 3 is a step to which the etching process of the present invention is applied. First, in step 1, for example, the polycrystalline silicon film 113 is removed by etching until the gate insulating film 112 is exposed under an etching condition with a high etching rate. By monitoring the remaining film amount 209 of the polycrystalline silicon film 113 up to the gate insulating film 112 using the film thickness monitor during this etching process, the remaining film amount can be kept constant for each wafer. it can. Step 2 is a step of performing a final etching (over-etching) on the residue that could not be etched in Step 1 above using a recipe with a margin that does not cause damage to the gate insulating film.

  For example, in the process 3 of processing the film to be etched in a plurality of steps, the mask dimension 210 of the hard mask 114 varies due to the process variation inherent in the process 1 or the process 2. If the mask dimension 210 is formed large in the previous process, it is conceivable to perform a process of thinning the mask dimension 210 by isotropic etching in the process 3, but the hard mask 114 is made of a material such as SiO2 or SiON. In the gate etching process used in process 3, it is difficult to perform the thinning process.

  However, in the etching processing method of this embodiment, the mask dimension 210 is acquired in advance, and in step 3, at least one parameter (variable parameter) of the recipe to be used is adjusted so that the etching result becomes the target value. Therefore, a desired gate length 211 can be obtained. Further, the gate insulating film 203 can be processed without being damaged.

  Further, even if the mask dimension 210 of the hard mask 114 can be processed without variation every time in the previous process 1 and the process 2, the mask dimension may vary due to disturbances such as changes in the apparatus over time in the process 3.

  According to the present embodiment, even in such a case, the change amount of the gate length 211 due to the disturbance is acquired in advance without adding feedback to the previous step 1 and step 2, and based on the acquired change amount. Since the recipe in step 3 is adjusted, a desired gate length 211 can be obtained. Further, the gate insulating film 203 can be processed without being damaged. In addition, when a feedback is applied to the previous process 1 or 2, a large-scale system is required, but in this embodiment, it is possible to cope with only the process 3, and the initial introduction load of the manufacturing system. (Time, cost, etc.) can be reduced.

FIG. 11 is a diagram for explaining how to use the film thickness monitor. Here, a case where the gate length is controlled by adjusting the O ₂ flow rate of the recipe will be described as an example. FIG. 11A shows the process when the flow rate of oxygen O ₂ is set to O ₂ = X [ml / min], and FIG. 11B shows the flow rate of oxygen O ₂ as O ₂ = X−a [ ml / min] shows the processing progress.

In Step 1 of FIG. 11A, etching is performed for a predetermined time at an oxygen O ₂ flow rate of X ml / min. In this case, the remaining film thickness (the film thickness up to the underlying gate insulating film) is Y. Next, in step 2, etching is performed until the base is reached. In the etching process in step 2, etching is performed with a predetermined angle θ according to the applied recipe. Therefore, the final gate length is C1.

On the other hand, when the final gate length is controlled, as shown in FIG. 11B, in step 1, the oxygen O _{2 is set} to Xa [ml / min] and etching is performed. In this case, the gate length can be controlled, but the etching rate also varies. As a result, the remaining film thickness in step 1 is Z (Z> Y). In step 2 to be performed next, since the recipe is fixed, the etching proceeds as in the case of FIG. That is, the etching proceeds with the predetermined angle θ. As a result, the final gate length is C2, which is different from the gate length C1 by C3 (this phenomenon can also be used for CD value control).

That is, in step 1 of FIG. 11B, if the CD value is controlled by controlling the flow rate of oxygen O ₂ , the etching rate of step 1 changes. If this time the influence of the CD value change in step 2 is greater than the influence of the CD value change due to oxygen O ₂ flow rate change in step 1, hides the CD value control by oxygen O ₂ flow rate change in step 1, the expected CD values that are not obtained are obtained.

  Therefore, it is necessary to always control the remaining film thickness Y or the remaining film thickness Z to a constant value, and for this purpose, it is necessary to monitor the film thickness in real time during the processing in Step 1.

  In the above description, a polycrystalline silicon film has been described as an example of a single film to be etched. However, the single film to be etched may be a laminated film with another film such as a metal film.

It is a figure which shows the etching processing apparatus concerning embodiment of this invention. It is a figure which shows a gate electrode formation process. It is a figure explaining the process of an etching processing apparatus. It is a figure which shows CD value controllability with respect to oxygen flow rate. It is a figure explaining the adjustment method of a recipe. It is a figure explaining the control mechanism of CD value when changing an oxygen flow rate. It is a figure which shows the modification of an etching processing apparatus. It is a figure which shows the control flow of CD value. It is a figure which shows the other example of the control flow of CD value. It is a figure explaining the determination factor of gate length. It is a figure explaining the usage method of a film thickness monitor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plasma etching processing chamber 1a Sample stand 1b Wafer 1c Plasma 2 Sensor 3 Additional sensor 4 Actuator 5 Recipe 6 Control model part 7 Inspection apparatus 8, 9, 10 Wafer 11 CD value control model 111 Silicon substrate 112 Gate insulating film 113 Polycrystalline silicon Film 114 Mask 115 Natural oxide film 201 Processing chamber 202 Gas supply means 203 Gas exhaust means 204 Sample 205 Sample stand 206 Plasma generation means 208 Apparatus state detection means 209 Controller 210 Inspection apparatus 300 Processing apparatus main body 301 Electromagnetic wave supply means 302, 303 Coil

Claims (6)

An etching processing apparatus for performing an etching process including a plurality of etching steps each applying a different recipe to a single film to be etched on a gate insulating film ,
A processing result estimation unit that monitors a plasma state in the etching processing chamber and estimates an etching processing result based on the monitored result;
A control model unit that adjusts the recipe based on the estimated etching processing result,
The recipe applied to the etching step in which the underlying layer in contact with the etching target film may be exposed among the plurality of etching steps is fixed to a preset recipe,
An etching apparatus that performs an etching process based on a recipe adjusted by the control model unit, which is applied to one of the remaining etching steps among the plurality of etching steps . An etching processing apparatus for performing an etching process including a plurality of etching steps each applying a different recipe to a single film to be etched on a gate insulating film ,
Means for multivariate analysis in real time of the plasma emission spectrum collected in the first etching step among the plurality of etching steps;
A processing result estimation unit that estimates an etching processing result based on the index value calculated by the multivariate analysis,
A control model unit that adjusts the recipe based on the estimated etching processing result,
The recipe applied to the etching step in which the underlying layer in contact with the etching target film may be exposed among the plurality of etching steps is fixed to a preset recipe,
An etching apparatus for performing an etching process based on a recipe adjusted by the control model unit for a recipe applied to a second etching step processed after the first etching step.   The etching processing apparatus according to claim 1, wherein the processing result estimation unit uses a prediction model constructed based on a processing result etched in advance. 3. The etching processing apparatus according to claim 1, wherein the prediction model stored in the processing result estimation unit is corrected based on a measurement value obtained from an inspection apparatus that inspects an etching processing result. Etching processing equipment. An etching processing method for performing an etching process consisting of a plurality of etching steps each applying a different recipe to a single film to be etched on a gate insulating film ,
Monitor the plasma state in the etching chamber and estimate the etching result based on the monitored result.
Adjust the recipe based on the estimated etching processing result,
The recipe applied to the etching step in which the underlying layer in contact with the etching target film may be exposed among the plurality of etching steps is fixed to a preset recipe,
One of the remaining etching steps among the plurality of etching steps is performed by performing an etching process based on the adjusted recipe. An etching processing method for performing an etching process consisting of a plurality of etching steps each applying a different recipe to a single film to be etched on a gate insulating film ,
The plasma emission spectrum collected in the first etching step among the plurality of etching steps is subjected to multivariate analysis in real time,
Estimating the etching processing result based on the index value calculated by the multivariate analysis,
Adjust the recipe based on the estimated etching processing result,
The recipe applied to the etching step in which the underlying layer in contact with the etching target film may be exposed among the plurality of etching steps is fixed to a preset recipe,
The second etching step processed after the first etching step performs an etching process based on the adjusted recipe.

Images