JP3872304B2 - Semiconductor manufacturing apparatus and semiconductor manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to semiconductor manufacturing technology. In particular, the present invention relates to a processing method for realizing reproducibility of processing results when performing wafer processing in a semiconductor manufacturing apparatus.
[0002]
[Prior art]
As semiconductor devices have been highly integrated in recent years, circuit patterns have been increasingly miniaturized, and the required processing dimension accuracy has become increasingly severe. In such a situation, the reproducibility of the processing state becomes important. For example, in an etching process that requires a high aspect ratio, an etching process has been realized while protecting the sidewall with an organic polymer in order to achieve anisotropic etching. Depends on the amount of etching products remaining in the processing chamber and the temperature of the wafer. Therefore, the amount of the remaining reaction product in the processing chamber varies from processing to processing, and if the temperature control of the wafer is insufficient, the sidewall protective film varies from wafer to wafer, resulting in poor etching shape reproducibility. cause. In a recent semiconductor manufacturing process, a device defect may be caused even with a variation in processing dimension of about 10 nm.
[0003]
For example, Japanese Patent Laid-Open No. 8-165585 discloses a method for dealing with such variations in plasma processing results.
[0004]
[Problems to be solved by the invention]
The disclosed example is characterized in that a monitor for measuring the self-bias voltage of the high-frequency electrode for generating plasma is provided, and the high-frequency power is adjusted so that the self-bias monitor value is constant. According to this disclosed example, generation of particles involved in etching such as ions and radicals generated in plasma can be expected to be performed with good reproducibility, but if the wafer temperature varies, the etching reaction on the wafer Since the speeds of the etching are different, the etching results vary. In addition, when highly reactive residual deposits remain on the wall surface of the processing chamber, there is a concern that the types and amounts of ions and radicals in the plasma vary and affect the etching result.
[0005]
An object of the present invention is to provide a semiconductor manufacturing apparatus and manufacturing capable of monitoring fluctuations in plasma processing characteristics and controlling the processing characteristics in response to the fluctuations to improve production yield and production efficiency. It is to provide a method.
[0006]
[Means for Solving the Problems]
The purpose is to measure the temperature of the wafer or the temperature of the wafer stage, a temperature adjustment function for arbitrarily maintaining the temperature of the wafer or the temperature of the wafer stage, a function of storing information on processing results in the past lot units, Has a function to store a relational expression that correlates the wafer or stage temperature and processing characteristics, and obtains the wafer temperature or stage temperature by using the relational expression so as to minimize the variation in the processing result in the past lot unit. Accordingly, this is achieved by controlling the wafer temperature or stage temperature during wafer processing for each single wafer processing.
[0007]
Further, the above object is to measure the temperature of the wafer or the temperature of the wafer stage, a temperature adjusting function for arbitrarily maintaining the temperature of the wafer or the temperature of the wafer stage, and a function of storing information of monitor results in past lot units. It has a function to store a relational expression that correlates the monitor result with the wafer or stage temperature. By using the relational expression, the wafer temperature or the stage temperature is obtained so as to minimize the variation of the monitoring result in the past lot unit. Thus the value is accomplished by controlling the temperature or the stage temperature of the wafer during wafer processing for each one process.
[0008]
Further, the above object is to provide means for measuring the temperature of the wafer or the temperature of the wafer stage, a temperature adjustment function for arbitrarily maintaining the temperature of the wafer or the temperature of the wafer stage, means for monitoring the processing state, and control of the processing apparatus. The system has a function to store the monitor value when past processing is performed well, and a function to store a relational expression that correlates the monitor result with the wafer or stage temperature, and the monitor value currently being processed. Compared with the monitor values that have been processed successfully in the past, the temperature of the wafer or the stage temperature is obtained by the above relational expression so that the deviation between the two is minimized, and when the next wafer is processed, the wafer temperature or This is achieved by controlling the stage temperature.
[0009]
Further, when the above-described control is performed, a history of how much the processing performance has deviated can be left by storing the temperature value actually changed. In addition, by setting a threshold value for the temperature value actually changed in advance and notifying the fact when the threshold value is exceeded, the maintenance time of the equipment can be known, and the production efficiency can be improved. Is also possible.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, a first embodiment will be described with reference to FIGS. FIG. 1 shows a schematic configuration diagram of a plasma etching apparatus for forming a pattern on a semiconductor substrate such as a Si wafer, which is a semiconductor manufacturing apparatus according to a first embodiment. FIG. 2 shows an example of the change in the processed shape of the device subjected to the etching process according to the number of processed sheets, and FIG. 3 shows a flowchart of the control performed in this embodiment.
[0011]
In FIG. 1, 1 is a Si wafer for performing an etching process, and 8 is an etching process chamber. Reference numeral 6 denotes an electrode for causing plasma discharge, and is provided with a shower hole 7 for uniformly introducing an etching gas into the processing chamber 8. 4 is an etching gas introduction pipe, and 18 is a vacuum exhaust port, which is connected to a vacuum pump (not shown here). Reference numeral 2 denotes a high frequency power source for applying high frequency power to the electrode 6, 5 denotes a ground, and 9 denotes an insulator for electrically isolating the electrode 6 from the chamber.
[0012]
Reference numeral 10 denotes a wafer stage, reference numeral 16 denotes a temperature measuring means for sensing the wafer temperature, and reference numerals 13 to 15 denote temperature adjusting mechanisms for the stage 10. In this embodiment, it is a cooling mechanism, 14 is a refrigerant circulator, 15 is a flow path to the substrate stage, and 13 is a refrigerant flow path provided in the substrate stage 10. The wafer stage 10 is capable of adsorbing the wafer 1 by electrostatic adsorption. After the adsorption, a gas having a high thermal conductivity, such as helium gas, is supplied from the gas flow path 17 provided through the stage 10 to the stage 10 and the wafer. 1 is satisfied, the temperature control of the wafer 1 is efficiently performed. 11 is a DC power source for electrostatic attraction, and 12 is a switch for performing an on / off operation.
[0013]
Reference numeral 19 denotes a control device for the entire apparatus, which includes a control computer for gas flow rate, pressure, high frequency power, and the like. A temperature control unit 21 in the control device 19 controls the stage temperature based on the value measured by the temperature measuring means 16. Reference numeral 20 denotes a processing parameter calculation part, which has a function of storing a relational expression that correlates processing result information such as wafer or stage temperature and etching rate and etching shape with information on processing results in the past lot unit. It is.
[0014]
In the plasma etching apparatus configured as described above, the wafer 1 to be processed is first placed on the stage, and an etching gas is introduced into the processing chamber 8 through the introduction tube 4 and the shower hole 7 and maintained at a predetermined pressure. Thereafter, the thin film formed on the Si wafer 1 can be processed by applying high frequency power to the upper electrode 6 from the high frequency power source 2 to generate plasma 3 and performing etching for a predetermined time. By the way, in such processing using plasma, the temperature characteristic of the substrate during processing is very important.
[0015]
This is because the substrate temperature affects the film formation rate in film formation such as sputtering and CVD, and the etching rate and processed shape in etching. As described above, for example, in etching that requires a high aspect ratio, a process of performing etching while protecting the side wall with an organic polymer is realized in order to realize anisotropic etching, but it becomes a protective film. The production of the organic polymer is affected by the amount of etching products remaining on the wall surface of the processing chamber 8, and if there are many remaining etching products, the protective film is too attached and the processed shape is shown in FIG. The d dimension tends to be thick.
[0016]
For example, since the amount of etching products that adhere to the wall of the processing chamber 8 and become deposits increases as the number of processed sheets increases, if the processing is continued under the same conditions, as shown by 22 in FIG. The processing shape may change within a lot. In recent state-of-the-art devices, the processing dimension is about to reach 0.1 μm, and even if the amount of change is about 10 nm, satisfactory characteristics may not be obtained.
[0017]
The feature of this embodiment is that the processing result information in the past lot unit and the relational expression that correlates the wafer or stage temperature with the processing characteristics are stored in the parameter calculation unit 20 in the control device 19 to control the wafer temperature. There is. The case of processing a product of a certain type will be described with reference to the flowchart shown in FIG.
[0018]
First, the wafer temperature T and shape data in lot units for the same type of products processed in the past are called up. For example, when the shape change within the lot changes as indicated by 21 in FIG. 2, the deviation Δdn from the desired shape dimension d is called for each wafer number n. Then, the deviation Δdn geometry, changes in wafer temperature ([Delta] T) and correlate the shape variation ([Delta] d) relationship, by substituting Δd = g (ΔT), the wafer temperature for correcting the Δdn Calculate (T + ΔT). By controlling the wafer temperature by changing the cooling capacity in the temperature control unit 21 based on the calculated value, it becomes possible to eliminate the shape dimension variation as shown by 22 in FIG.
[0019]
Here, as the shape data when processed at the wafer temperature T, data obtained by processing an actual product may be stored, or data obtained by processing a trial wafer having the same material and mask pattern shape as the product may be used. good. In addition, the relational expression that correlates the change (ΔT) of the stage temperature and the shape variation (Δd) needs to be obtained in advance using a trial wafer having the same material and mask pattern shape as the product .
[0020]
Here, the wafer temperature control is performed by heat conduction between the wafer stage 10 and the wafer 1 after controlling the temperature of the wafer stage 10. When the temperature range to be changed is small, the wafer temperature can be controlled by keeping the pressure of the helium gas constant and changing the stage temperature. However, when the temperature range to be changed is large, the above method takes time to bring the wafer temperature to a desired temperature. For example, since it takes about 10 minutes to change the temperature from -5 ° C to 5 ° C, the productivity is lowered. In such a case, the temperature of the wafer 1 is controlled at a high speed by setting the stage temperature to be low in advance and controlling the temperature of the wafer 1 to increase by lowering the pressure of the helium gas. It becomes possible.
[0021]
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 4 shows a schematic configuration diagram of the plasma etching apparatus according to the present embodiment. The apparatus configuration is the same as that of the first embodiment, but the processing apparatus 8 has means for monitoring the processing state. 23. In this embodiment, plasma emission is measured as a state monitor. FIG. 5 shows an example of a change in the state monitor value and a change in the processing shape according to the number of processed sheets. FIG. 6 shows a flowchart of the control performed in this embodiment.
[0022]
In the parameter calculation unit 20 in the control device 19, the state monitor value when the same shape dimension d as the design dimension is obtained, the fluctuation information of the state monitor value in the past lot unit, the wafer or stage temperature and the state monitor value It has a relational expression that correlates The relational expression that correlates the wafer or stage temperature and the state monitor value can be obtained by having the relational expression that correlates the fluctuation of the monitor value and the shape fluctuation, and the relational expression that correlates the shape fluctuation and the wafer or stage temperature. . These correlation equations are created by creating a database using status monitor values, temperature, and shape data obtained by processing the same type of products processed in the past, or data obtained by processing a trial wafer that has the same material and mask pattern shape as the product. It is desirable to create a database.
[0023]
The case of processing a product of a certain type will be described with reference to the flowchart of FIG. First, the state monitor value P when the same shape dimension d as the design dimension is obtained, the wafer temperature T and the state monitor data Pn for each product in the same type of product processed in the past (in the case of 25 lots, n = n = 1-25) are called in lot units.
[0024]
For example, when the processing value monitor value Pn in the lot changes as indicated by 26 in FIG. 5, a deviation ΔPn (= Pn−P) from the state monitor value P when the same shape dimension d as the design dimension is obtained. ) Is calculated for each wafer. Next, the predicted value Δdn of the shape dimension deviation can be obtained from the relational expression Δdn = f (ΔP) that correlates the obtained state monitor value deviation (ΔP) and the shape variation (Δd). Furthermore, the change in wafer temperature ([Delta] T) and correlate the shape variation ([Delta] d) relationship, [Delta] d = by substituting g ([Delta] T), equation [Delta] T = g ^-1 correlating the wafer temperature and the state monitor value (F (ΔP)) is obtained, and the wafer temperature for correcting the monitor value ΔPn is calculated (ΔTn). By controlling the wafer temperature by changing the cooling capacity in the temperature control unit 21 based on the calculated value, it becomes possible to eliminate the fluctuation of the state monitor value as shown in 26 of FIG. 6 to 27 can be eliminated.
[0025]
Here, examples of the process state monitor include power applied to plasma, current, voltage, impedance, self-bias voltage, and plasma emission. As an example, results obtained by the inventors to obtain a relational expression between a monitor value of plasma emission and a processing dimension are shown below. By performing principal component analysis of plasma emission, and by performing multiple regression analysis using the first principal component to third principal component obtained from principal component analysis as explanatory variables, minute shape variations and plasma emission in polysilicon etching are performed. The relational expression correlating with the monitor value is obtained. In etching using plasma of HBr and Cl2, Δd = α1 × PC1 + α2 × PC2 + α3 × PC3. Here, PC1, PC2, and PC3 are respectively the first principal component to the third principal component obtained from the principal component analysis of plasma emission, α1 = 0.83, α2 = 0.1, and α3 = 3.2. It was.
[0026]
Next, a third embodiment of the present invention will be described with reference to the flowchart shown in FIG. The apparatus configuration and monitoring means in this embodiment are the same as those in the second embodiment shown in FIG. 4, but the same shape dimension d as the design dimension is obtained in the parameter calculation unit 20 in the control apparatus 19. Condition monitor value, wafer or stage temperature and the relational expression correlating the state monitor value, and comparing the monitor value currently being processed with the monitor value that has been processed successfully in the past, the relationship The characteristic is that the temperature of the wafer or the stage temperature is obtained so that the deviation between the two is minimized by the equation, and the wafer temperature or the stage temperature is controlled according to the value when the next wafer is processed.
[0027]
That is, when processing a product of a certain type, first, the state monitor value P when the same shape dimension d as the design dimension is obtained is called. The difference ΔP1 between the state monitor values P1 and P in the first process is calculated. Next, a predicted value Δd1 of the shape dimension deviation is obtained from a relational expression Δdn = f (ΔP) that correlates the obtained state monitor value deviation (ΔP) and the shape fluctuation (Δd). Further, a relational expression for correlating the wafer temperature with the state monitor value by substituting into the relational expression for correlating the change in wafer temperature (ΔT) and the shape fluctuation (Δd), Δd = g (ΔT) (ΔT = g ⁻¹ ( f (ΔP)) is obtained, and the wafer temperature for correcting the monitor value deviation ΔP1 is calculated (ΔT1). Based on this calculated value, the cooling capacity is changed in the temperature control unit 21, and the wafer temperature control is performed at the time of the next wafer (second sheet) processing to eliminate the fluctuation of the state monitor value. These operations are repeated one after another, that is, a temperature correction value calculated based on the deviation between the state monitor value P when the same shape dimension d as the design dimension is obtained and the state monitor value Pn in the n-th process is obtained. Reflect to the (n + 1) th sheet. In this embodiment, the first processing wafer at the beginning of the lot is not corrected, but only the first wafer is processed in the same manner as in the second embodiment, that is, the processing state at the beginning of the lot that has been processed in the past. The correction location may be obtained from the monitor information.
[0028]
By providing the control function as described above in the dry etching apparatus and having the function of selecting which function to use as necessary, a semiconductor manufacturing apparatus with less processing variation is obtained.
[0029]
Furthermore, using the control function as described above, the function to store the changed temperature value and output when the changed temperature value exceeds the preset value is added. As a result, device management can be performed efficiently. That is, the larger the temperature value that needs to be corrected, the higher the possibility that the state of the apparatus, for example, the contamination of the processing chamber wall surface, the input power to the plasma, the processing chamber wall surface temperature, and the like fluctuate.
[0030]
Therefore, by determining a certain threshold value and immediately outputting that when it exceeds that value, it will prevent an abnormal situation of the device, and also perform maintenance at an appropriate time. . The output form may be an alarm such as a buzzer, a display on the operation panel, or a display on the personal computer of the device operator.
[0031]
Although the above has been described by taking a dry etching apparatus as an example, similar effects can be obtained with respect to a plasma CVD apparatus, a sputtering apparatus, and a process using them. In these cases, however, the object to be controlled in the processing is not the processing shape but the film deposition rate and film quality.
[0032]
【The invention's effect】
As described above, according to the present invention, fluctuations in processing characteristics can be monitored and processing characteristics can be controlled in response to the fluctuations, so that production yield and production efficiency can be improved. It becomes. Also, device management can be performed efficiently.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating the structure of a semiconductor manufacturing apparatus according to a first embodiment of the present invention.
FIG. 2 is a graph for explaining a controlled object in the first embodiment of the present invention.
FIG. 3 is a process flow for explaining the operation in the first embodiment of the present invention.
FIG. 4 is a schematic diagram illustrating the structure of a semiconductor manufacturing apparatus according to a second embodiment of the present invention.
FIG. 5 is a graph for explaining a controlled object in the second embodiment of the present invention.
FIG. 6 is a process flow for explaining the operation in the second embodiment of the present invention.
FIG. 7 is a process flow for explaining the operation of the third embodiment of the present invention.
[Explanation of symbols]
1 ... wafer, 2 ... high frequency power supply, 3 ... transfer robot,
4 ... Etching gas introduction pipe, 5 ... Ground, 6 ... Electrode, 7 ... Shower hole,
8 ... Etching chamber, 9 ... Insulator, 10 ... Wafer stage, 11 ... DC power supply,
12 ... Switch, 13-15 ... Stage temperature adjusting mechanism, 16 ... Temperature measuring means,
17 ... He gas introduction pipe, 18 ... exhaust port, 19 ... control device,
DESCRIPTION OF SYMBOLS 20 ... Parameter calculating part, 21 ... Temperature control part, 23 ... Luminescence sensor 24 ... Luminescence detector, 25 ... Luminescence analysis part.

Claims (5)

A processing chamber for performing plasma processing on a wafer, means for generating the plasma in the processing chamber, a wafer stage for loading the wafer and processing the wafer with the plasma, and controlling the entire apparatus In a semiconductor manufacturing method using a semiconductor manufacturing apparatus equipped with a control device,
Wherein the wafer stage is provided with a hand stage you measure the temperature or both of the internal temperature or the stage of the wafer, the temperature control function to keep the temperature of the internal temperature or the stage of the wafer optionally,
The control device has a function of storing processing result information including wafer temperature and deviation data from desired shape dimensions in the past lot units, and a relational expression correlating wafer or stage temperature with shape variation. ,
The relationship determined temperature or stage temperature of the wafer so that the variation in the definitive processing results to each lot of the past of the same kind products is minimized by formula, the temperature of the wafer during wafer processing for each one proceeds according to the value or stages, A semiconductor manufacturing method characterized by controlling temperature. A processing chamber for performing plasma processing on a wafer, means for generating the plasma in the processing chamber, a wafer stage for loading the wafer and processing the wafer with the plasma, and controlling the entire apparatus In a semiconductor manufacturing method using a semiconductor manufacturing apparatus equipped with a control device,
Wherein the wafer stage is provided with a hand stage you measure the temperature or both of the internal temperature or the stage of the wafer, the temperature control function to keep the temperature of the internal temperature or the stage of the wafer optionally,
Into the processing chamber comprises means for monitoring the state of the process,
The control device has a function of storing information on monitor results in the past lot unit, a state monitor value when the same shape dimension as the design dimension is obtained, a relational expression for correlating the monitor value variation and the shape variation, and It has a function of storing a relational expression correlating the wafer or stage temperature and the state monitor value from a relational expression correlating the shape variation with the wafer or stage temperature ,
Determined temperature or stage temperature of the wafer so that the variation in the definitive monitoring results to each lot of the past of the same kind products by the relational expression becomes minimum, the temperature or the stage temperature of the wafer during wafer processing for each one proceeds according to the A method of manufacturing a semiconductor, characterized in that the method is controlled. A processing chamber for performing plasma processing on a wafer, means for generating the plasma in the processing chamber, a wafer stage for loading the wafer and processing the wafer with the plasma, and controlling the entire apparatus In a semiconductor manufacturing method using a semiconductor manufacturing apparatus equipped with a control device,
Wherein the wafer stage is provided with a hand stage you measure the temperature or both of the internal temperature or the stage of the wafer, the wafer temperature, or a temperature control function to keep any stage internal temperature,
Into the processing chamber comprises means for monitoring the state of the process,
Wherein the control device, a function of past processing stores the monitoring value at the time of satisfactorily performed, the status monitor value when the same geometry as the designed size is obtained, the monitoring results and the wafer or stage temperature and A function of storing a relational expression for correlating
The monitor value currently being processed is compared with the monitor value that has been successfully processed in the past, and the wafer temperature or stage temperature is obtained by the above relational expression so that the deviation between the two is minimized. A semiconductor manufacturing method characterized by controlling a wafer temperature or a stage temperature according to a value. A semiconductor manufacturing apparatus for carrying out the semiconductor manufacturing method according to claim 1 ,
The controller functions to store and process result information including data of displacement, the relationship engagement expression correlating wafer or stage temperature and shape change from geometry to be obtained with a wafer temperature in a past batches, or, A function for storing information on monitoring results in units of past lots, a state monitor value when the same shape dimension as the design dimension is obtained, a relational expression that correlates the change in the monitor value and the shape change, and the shape change and the wafer or A function for storing a relational expression for correlating a wafer or stage temperature and a state monitor value from a relational expression for correlating the stage temperature, or a function for storing a monitor value when a past process is successfully performed, and a design dimension Store the relational expression that correlates the monitor value with the wafer or stage temperature when the same shape dimensions are obtained. As well as a function, a semiconductor manufacturing apparatus, wherein <br/> that comprises means for selecting these relations. The semiconductor manufacturing apparatus according to claim 4 .
A semiconductor manufacturing apparatus characterized by comprising means for storing a value for which temperature control has been performed, and notifying when a value of the changed temperature exceeds a preset specified value.

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