Etching system and etching method

Abstract

The etching system according to the present invention comprises an etching device (103) for etching a wafer (104), a measuring device (101) for measuring a pattern formed on the surface of the wafer (104) etched by the etching device (103), and a calculating device (102) for providing etching conditions to the etching device (103). The calculating device (102) calculates a first parameter that is highly correlated with a temperature condition among the etching conditions and a second parameter that is less correlated with the first parameter based on the measurement result of the pattern from the measuring device (101), calculates a temperature condition in which the first parameter is within an allowable range based on the calculated first parameter, determines whether the calculated second parameter is within an allowable range, and if the calculated second parameter is outside the allowable range, provides an etching condition in which the conditions other than the temperature condition are changed, and if the calculated second parameter is within the allowable range, provides an etching condition in which the temperature condition is changed to the calculated temperature condition.

Description

Technology Field

[0001] The present invention relates to an etching system and an etching method that improve in-plane shape uniformity of a wafer. Background Technology

[0002] With the three-dimensionalization of semiconductor device structures, the demand for manufacturing methods that can uniformly create complex structures on a wafer surface is increasing year by year. In the manufacturing of semiconductor devices, a pattern mask is formed using an exposure device, and then processed using an etching device to form a target pattern on the front surface of the wafer. In addition, to verify that the created pattern is of the desired size, it is common practice to perform measurements using semiconductor inspection devices such as CD-SEM (Critical Dimension Scanning Electron Microscope) or OCD (Optical Critical Dimension).

[0003] As a conventional etching technique, an etching system is known that improves the in-plane uniformity of the Critical Dimension (CD) value corresponding to the width of the Top-View of the pattern by controlling the in-plane temperature of the wafer using a plurality of heating elements during etching. For example, Patent Document 1 describes an etching system and an etching method in which the in-plane uniformity of the CD value is improved by etching by realizing a temperature profile of a plurality of heating elements determined from the relationship between the CD shift amount of each temperature measured in advance and the temperature, and the CD value of the wafer before processing. Here, the CD shift amount refers to the amount of change in the CD value before and after etching. Prior art literature

[0004] Japanese Publication No. 2013-77859 The problem to be solved

[0005] In the above-described conventional technology, problems arose because the following points were not sufficiently considered. That is, in the above-described conventional technology, the uniformity of the CD value within the wafer plane is improved by controlling the electrode temperature composed of a plurality of heating elements. However, in recent semiconductor devices, the device structure is becoming three-dimensional, and uniformity of multiple parameters including cross-sectional shape, not just a single parameter called the CD value, is required.

[0006] Meanwhile, when considering the uniformity of multiple parameters, it is easy to think that uniformity can be improved by controlling the electrode temperature of each parameter, as in the prior art. However, in reality, not all parameters have temperature sensitivity. As shown in Patent Document 1, the CD value has high temperature sensitivity, and the uniformity of the CD value within the wafer surface can be improved by adjusting the temperature of each electrode, which consists of multiple heating elements that set the wafer temperature. However, it was found that there are parameters with low temperature sensitivity and small fluctuations due to temperature. Regarding these parameters, it was found that even if etching is performed solely by controlling the electrode temperature calculated from temperature sensitivity as in the prior art, it is difficult to improve uniformity within the surface, and there is a risk that the desired shape cannot be obtained.

[0007] As such, conventional technology has not considered realizing in-plane uniformity of multiple parameters including parameters with low temperature sensitivity. The objective of the present invention is to provide an etching system and an etching method that improve the processing yield by considering the improvement of in-plane uniformity of multiple parameters including parameters with low temperature sensitivity. means of solving the problem

[0008] An etching system, which is an embodiment of the present invention, comprises an etching device for etching a wafer, a measuring device for measuring a pattern formed on the surface of a wafer etched by the etching device, and a calculating device for providing etching conditions to the etching device. The calculating device calculates a first parameter that is highly correlated with a temperature condition among the etching conditions and a second parameter that is less correlated with the first parameter based on the measurement result of the pattern from the measuring device, calculates a temperature condition in which the first parameter is within an allowable range based on the calculated first parameter, determines whether the calculated second parameter is within an allowable range, and if the calculated second parameter is outside the allowable range, provides an etching condition in which the conditions other than the temperature condition are changed, and if the calculated second parameter is within the allowable range, provides an etching condition in which the temperature condition is changed to the calculated temperature condition. Effects of the invention

[0009] According to the present invention, by using data measured by a measuring device, conditions other than temperature are re-examined regarding the in-plane distribution of a first parameter with temperature sensitivity as well as the non-uniformity of a second parameter with low temperature sensitivity, and by repeating this process until the distribution of the first and second parameters falls within an acceptable range, and by adjusting the heater to obtain a temperature distribution by applying a modification to the temperature distribution corresponding to the original target CD value, the processing yield is improved. Brief explanation of the drawing

[0010] FIG. 1 is a schematic diagram showing the device configuration of a semiconductor etching system according to an embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing the configuration of a wafer stage equipped with a device of a semiconductor etching system according to an embodiment. FIG. 3 is a plan view schematically showing an example of the arrangement of a heater zone on the upper surface of a wafer stage according to an embodiment. FIG. 4 is a flowchart showing the flow of operation within a computing device according to an embodiment. Figure 5 is a diagram schematically showing measurement locations within the wafer surface. Figure 6 is a schematic diagram explaining the difference between CD and the slope in cross-section. Figure 7 is an example of an SEM image of a line pattern of a semiconductor device, a corresponding cross-sectional schematic, and a secondary electronic signal waveform of the SEM. FIG. 8 is an example of a second electronic signal waveform and its first derivative waveform that produce a feature quantity which is a three-dimensional shape indicator, and a corresponding three-dimensional shape. Figure 9 shows the values ​​of CD, the first parameter calculated from the SEM image, and the left-right difference of the slope, the second parameter. Figure 10 is a graph of temperature sensitivity of the first parameter CD and the left-right difference of the second parameter slope. Figure 11 is a diagram illustrating a method for calculating the temperature of each electrode to obtain uniform parameter values ​​within the plane from a graph of temperature sensitivity. Figure 12 is a graph illustrating a state of low temperature sensitivity. Figure 13 is a diagram showing the reduction of non-uniformity of CD values ​​by temperature control and the non-uniformity of the left-right difference of the slope. Figure 14 is a diagram showing the reduction of unevenness in the left-right difference of the slope due to a change in the type of gas. Specific details for implementing the invention

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Furthermore, the present invention is not limited by these embodiments. Also, in the description of the drawings, the same parts are indicated by the same reference numerals. If there are multiple components having the same or similar functions, different subscripts may be assigned to the same reference numerals for description. Additionally, if there is no need to distinguish these multiple components, the subscripts may be omitted for description. To facilitate understanding of the invention, the actual location, size, shape, and range of each component shown in the drawings may not be indicated. Therefore, the present invention is not necessarily limited to the location, size, shape, and range disclosed in the drawings.

[0012] [Example 1]

[0013] An embodiment of the present invention will first be described using FIG. 1. FIG. 1 is a schematic diagram showing the configuration of a semiconductor etching system according to an embodiment of the present invention. In this figure, the overall configuration of the semiconductor etching system is schematically shown, and as a semiconductor wafer processing device such as an etching processing device, a device for processing a semiconductor wafer to realize the distribution of a specific physical quantity (for example, the shape or dimension of a circuit pattern formed on the wafer surface) in the in-plane direction of the wafer is shown.

[0014] The semiconductor etching system of the present embodiment comprises an etching device (103) having a wafer stage (105) having a function to variably adjust the temperature distribution in the in-plane direction of the wafer (104) in which a wafer (104) is installed in the container of the etching device (103), a measuring device (101) capable of measuring the distribution of a specific physical quantity in the wafer plane, a calculator capable of calculating a plurality of parameter values ​​including CD values ​​obtained from the result of measuring a pattern formed on the surface of a wafer at a plurality of preset positions by the measuring device (101), and calculating the temperature of a plurality of locations of the wafer or the stage supporting it using the parameter values, and a calculating device (102) having a mechanism for determining whether the non-uniformity of the parameter is within an allowable range.

[0015] FIG. 2 is a cross-sectional view schematically illustrating the configuration of a wafer stage and temperature control of an etching apparatus according to an embodiment. The wafer stage (105) is provided with a plurality of heaters (201) for heating and a refrigerant flow path (204) for cooling, located below the surface on which the processing wafer (205) is placed. By adjusting the amount of heat generated by the plurality of heaters (201) and the temperature of the refrigerant, the temperature distribution in the in-plane direction of the wafer stage (105) is adjusted. The plurality of heaters (201) are installed in each area of ​​the wafer stage (105), and the area can be divided in a concentric circle shape as shown in FIG. 3 (a) or in a rectangular shape as shown in FIG. 3 (b). These divided areas are called electrodes. The number or size of the divisions is not limited to those exemplified. Additionally, 202 is a temperature controller for the electrode of the heater, and although not shown, it uses sensor values ​​obtained from a plurality of temperature sensors installed on the electrode of the heater to adjust the temperature of the upper surface of the stage on which the wafer is placed so that the wafer temperature calculated by the calculation device (102) is adjusted. This control of adjustment is performed by the heater control unit (203).

[0016] The refrigerant flow path (204) circulates and flows between the refrigerant temperature controller connected via a pipe not shown, and is controlled to a temperature within a predetermined range by the refrigerant temperature controller. In the drawing, the refrigerant flow path (204) is installed below the heater (201), but it may also be installed above it. Additionally, if the wafer temperature can be controlled to a desired value using only the heater (201), the refrigerant does not need to be used.

[0017] The calculation device (102) is a device that, before etching the wafer, provides etching conditions that enable uniformity of CD values ​​or shapes within the wafer plane, calculates the stage temperature for this purpose, and transmits it to the etching device (103). Figure 4 shows a flowchart performed by the calculation device. In this embodiment, etching treatment is first performed using a calculation wafer. A calculation wafer is another wafer that is pre-processed to obtain treatment conditions that allow the distribution of CD values, shapes, and dimensions of the film structure on the wafer after processing to be within a desired range before etching a wafer (actual wafer) for manufacturing a semiconductor device (device), and in the in-plane direction of the film structure on the wafer after processing, and in which parameters necessary for determining said treatment conditions are detected. At least, it is a wafer that has a film structure or pattern that is identical to or can be considered equivalent to the film structure or pattern having a plurality of film layers including the film to be processed placed on the upper surface of the actual wafer.

[0018] In the first step 400, data (processing recipe data) indicating the operation of the etching device (103), including processing conditions such as the flow rate of the processing gas, the pressure inside the processing chamber, the temperature of the wafer during processing, and its distribution, and a so-called processing recipe when the etching device (103) shown in FIG. 1 processes a wafer for output, is acquired by the computing device (102) through a communication means and recorded in an internal memory device. Next, in step 401, etching processing is performed using the wafer for output based on the obtained processing recipe data. In this embodiment, processing is performed on each of a plurality of wafers for output based on different temperature conditions.

[0019] As described in Patent Document 1, it is known that the CD value has temperature sensitivity and varies depending on the temperature. In this regard, in Step 401, a process is performed to calculate the temperature sensitivity of a desired pattern by changing the temperature for a plurality of output wafers. In this embodiment, etching treatment is performed on each of two output wafers under conditions where the wafer temperature during processing is 10°C and 50°C in the in-plane direction, particularly under conditions where the temperature detected at each of a plurality of locations on the wafer or wafer stage during processing is within a predetermined allowable range, and the CD value and its distribution are detected from these output wafers.

[0020] Next, in step 402, measurements are performed on a plurality of processing output wafers. In this embodiment, the CD value of the pattern is measured using a conventional CD-SEM device. This is because it allows for high-speed measurement through non-destruction. In this embodiment, for a plurality of predetermined locations on the upper surface (501) of each output wafer, an image of the desired pattern at each location is acquired from the Top View using a CD-SEM device. At this time, as shown in FIG. 5, the distribution of the in-plane direction of the measurement values ​​obtained for the plurality of locations on the upper surface (501) of the output wafer can be calculated. Finally, the shape after processing formed at each of the predetermined inner locations among the dies (502) on the upper surface (501) of the output wafer corresponding to each semiconductor device (chip) cut from the wafer is measured, and SEM images (503a, 503b …) are acquired.

[0021] A CD-SEM image is a result of detecting secondary electrons excited from atoms by scattering incident electrons within a sample in a SEM, and displaying them as brightness (luminance) for each pixel of the image. It represents the intensity of the detected secondary electron signal and contains information on the three-dimensional shape of the pattern. In this embodiment, multiple SEM images are acquired within the surface of a output wafer etched under conditions where the wafer temperature is 10°C, and multiple images of the output wafer etched under conditions of 50°C. Images were acquired for each pattern at a designated location within the area of ​​each of the 110 dies (502) formed on the upper surface (501) of each output wafer.

[0022] In addition, the location where the temperature of the wafer or wafer stage in this embodiment is detected is positioned within the projection plane viewed from above, below the area of ​​each heater (201) where the output or heating amount is adjusted by the electrode control device so that the outside temperature becomes a desired value, and the number of such locations is equal to or greater than the number of heaters (201). Even when the wafer temperature becomes a predetermined value in the in-plane direction as in steps 400 and 401, the output or heating amount of each heater (201) is adjusted so that the non-uniformity of each value is within a desired range for the set of temperature values ​​detected at multiple locations. In the example of a heater (201) having a rectangular shape area shown in FIG. 3 (b), the dimensions of each heater are smaller than the dimensions of each die (502), and in this example, each heater (201) is adjusted based on the temperature detected at more locations than the number of dies (502).

[0023] Next, in step 403, shape parameters representing a three-dimensional shape are calculated from the acquired CD-SEM image. As a first parameter, a parameter with high temperature sensitivity, for example, a CD value, is calculated, and as a second parameter, a parameter with low temperature sensitivity—that is, a parameter that has low correlation with wafer temperature and high correlation with other processing conditions other than temperature—for example, the left-right difference of the slope of the cross-section, which can be experimentally confirmed to have low temperature sensitivity, is calculated. Furthermore, in the present invention, the parameter with low correlation with temperature includes a parameter that has no correlation with temperature.

[0024] As shown in Fig. 6, the CD value represents the width of the cross-section, and the left-right difference of the slope is the difference in width between the left and right sides of the pattern cross-section |S1-S2|. When creating a pattern by SADP (Self-Aligned Double Patterning), the in-plane uniformity of this parameter becomes important.

[0025] Here, SEM images and a method for calculating parameters from those images are described. Figure 7 shows an example of a SEM image targeting a line pattern of a semiconductor device. Figure 7(a) is a two-dimensional SEM image that is a Top View image of the line pattern. In this SEM image, there is one line pattern extending in the Y direction within the XY plane of the image corresponding to the wafer plane. In this image, each pixel has a brightness (luminance).

[0026] FIG. 7(b) is an example of the cross-sectional shape of a pattern at the position AB in FIG. 7(a), corresponding to the XZ cross-section. FIG. 7(c) is an example of a secondary electron signal waveform of an SEM corresponding to the shade of the image (701) in FIG. 7(a) and the cross-sectional shape in (b). This waveform is also called a line profile. This signal waveform is highly sensitive to the angle of inclination of the cross-section of the pattern being measured, and the signal amount at the sidewall portion of the pattern is greater than the signal amount at the flat portion of the pattern. The bevel portion (702) of the cross-sectional shape in FIG. 7(b) corresponds approximately to 704 of the signal waveform in (c), and the flat portion (703) corresponds to 705. As such, it is known that the signal waveform changes according to the cross-sectional shape of the pattern.

[0027] Meanwhile, from this signal waveform, a feature quantity, called a characteristic quantity, can be calculated to estimate the cross-sectional shape. The characteristic quantity refers to values ​​such as peaks or widths obtained from the second electronic signal waveform, its first derivative waveform, and its second derivative waveform, respectively, and is a shape indicator representing the characteristics of the pattern shape. An example of a characteristic quantity is shown in FIG. 8. (a) represents the second electronic signal waveform, (b) represents its first derivative waveform, and (c) represents the cross-sectional shape of the pattern. The value of the waveform width indicated by the arrow is called a characteristic quantity, and from the relationship of these multiple characteristic quantities, the pattern to be measured has a shape such as a width (801, 804), tailing (802, 805), and a side angle of inclination (803, 806).

[0028] In this embodiment, FIG. 9 shows that the values ​​of the first parameter, the CD value, and the second parameter, the left-right difference of the slope, were obtained from the SEM image by this calculation method. (a) is the CD value of the first parameter, and (b) is the value of the second parameter, the left-right difference of the slope. The white circle indicates a temperature condition of 10°C when the wafer for calculation is processed, and the black circle indicates 50°C. The horizontal axis of the graph represents 110 locations measured on each etched wafer.

[0029] Next, they are converted into a graph of temperature sensitivity with the horizontal axis representing temperature, and the respective initial non-uniformity σi is calculated (Fig. 10). In this embodiment, the values ​​of the first and second parameters were used after coordinate transformation from the CD-SEM measurement coordinates to the electrode coordinates of the etching device. The initial non-uniformity (standard deviation) of the CD value of the first parameter for a 10°C wafer was σCD(10deg)=0.91, and the non-uniformity for a 50°C wafer was σCD(50deg)=0.76. The non-uniformity of the left-right difference of the slope of the second parameter was σS(10deg)=0.16 for a 10°C wafer and σS(50deg)=0.08 for a 50°C wafer.

[0030] Next, in step 404 of the flowchart of FIG. 4, the electrode control temperature of the first parameter (CD value) is calculated. Using FIG. 11, the method for calculating the temperature of each electrode to obtain an in-plane uniform parameter value from the graph of temperature sensitivity is explained. For explanation, (a) shows only electrode numbers R1 (○) and R2 (△) plotted, where CD values ​​obtained by measuring a calculation wafer etched at temperatures T1 and T2 using CD-SEM are plotted, and the dashed line is a first-order linear approximation line for each electrode. From this first-order linear approximation line, the temperature of each electrode to be used as the target CD value shown in the graph is calculated. That is, as indicated by the arrow, the temperature T of electrode R1 is calculated from the intersection point of the first-order linear approximation line of electrode R1 and the target. R1 , temperature T of electrode R2 from the intersection point with the first linear approximation of electrode R2 R2 It is being saved.

[0031] In addition, as in (b), when multiple data exist by performing wafer processing for calculation at multiple temperatures such as T3, T4, etc. in addition to T1 and T2, the approximation is done using a quadratic curve approximation line such as the dashed line in (b) instead of a linear approximation line.

[0032] Here, we explain parameters with low temperature sensitivity. The electrode is part of the etching device and has a controllable temperature range. For example, if the minimum temperature is Tmin and the maximum temperature is Tmax, the wafer processing temperatures T1 or T2 for calculation are typically within the range of Tmin and Tmax. Also, in Fig. 11, the calculated temperature T R1 , T R2 It is also within the range of Tmin and Tmax. Meanwhile, as shown in Fig. 12, when the slope with respect to temperature is small, the temperature T obtained from the intersection point of the approximation line of each electrode and the target value. R1 Ina T R2The temperature becomes outside the range of Tmin and Tmax. In this case, the electrode temperature cannot be realized. Furthermore, a small slope like this means that even if the temperature is changed between Tmin and Tmax, the change in parameter values ​​is small and the temperature sensitivity is low.

[0033] Step 405, the next flow of FIG. 4, is a process for determining whether the non-uniformity of the second parameter (left-right difference of the slope) with low temperature sensitivity is within a predetermined allowable range. When the non-uniformity is within the specified value (Yes), it is determined that the non-uniformity of both the first parameter (CD value) and the second parameter calculated in Step 404 for the shape after processing by etching treatment based on the original processing recipe data including temperature conditions is within a predetermined allowable range required for the semiconductor device or its manufacturing, and the process proceeds to the next step 406, which is a process for processing an actual wafer for manufacturing a semiconductor device.

[0034] Meanwhile, if the non-uniformity of the second parameter is outside the specified value (No), even if the non-uniformity of the first parameter (CD value) is within the allowable range due to temperature control based on the original processing recipe data, there is a risk that a problem may arise in the semiconductor device or in its manufacturing in terms of the second parameter (left-right difference of the slope). In this case, proceed to the process after step 407, and modify the processing recipe data so that the processing conditions of the wafer that are highly correlated with the parameter are changed so that the non-uniformity of the second parameter becomes a value within the allowable range.

[0035] Specifically, when the data of FIG. 10 is used, the initial non-uniformity σCD (10deg) and σCD (50deg) of the CD value obtained by processing the wafer for output at temperature conditions of 10°C and 50°C, respectively, which are included in the processing recipe data as initial values, are calculated, and these values ​​are compared with the upper limit of the allowable range of the non-uniformity of the CD value. If it is determined that the non-uniformity value is outside the allowable range with the upper limit value as the threshold, the temperature value and distribution to be set at the plurality of locations where the temperature is detected are calculated by a calculation device in order to make the non-uniformity of the CD value within the allowable range. The set of temperature setting values ​​at the plurality of locations during processing as such processing conditions is formed as a temperature group, and the non-uniformity σCD (T3 group) resulting from processing the wafer for output by adjusting the heater (201) to these temperatures under processing conditions using the temperature group T3, which is modified to improve the non-uniformity of the CD value, is as shown in FIG. 13 (a).

[0036] Meanwhile, Figure 13 (b) plots the non-uniformity of the left-right difference of the slope σS (10deg) and σS (50deg), and it can be seen that when the specified value of the non-uniformity is σ=0.3, the non-uniformity of the left-right difference of the slope is within the specified value (Yes). In this case of data, since the non-uniformity of the CD value after temperature control and the non-uniformity of the left-right difference of the slope can be suppressed within the specified value, it can be seen that actual wafer processing can proceed based on the processing recipe data with temperature group T3 as the processing condition.

[0037] Meanwhile, if the non-uniformity of the second parameter is outside the specified value (No), it means that even if the non-uniformity of the first parameter (CD value) is brought within the specified value by temperature control, the second parameter (left-right difference of the slope) cannot be brought within the specified value, and thus the non-uniformity of both parameters cannot be brought within the specifications. In this case, in this embodiment, in order to reduce the non-uniformity of the left-right difference of the slope, the conditions of the etching treatment other than temperature are re-examined and the conditions are set again. This step becomes Step 407 of FIG. 4.

[0038] In the case of another experimental example shown in FIG. 14, the difference between the left and right sides of the slope after processing of the output wafer processed with arbitrary temperature groups T2 and T3 as processing conditions was non-uniformity exceeding the specified value, and the non-uniformity could not be reduced even by changing the temperature. In this example, in step 407, the type of gas is changed and the temperature condition is changed to temperature group T3, thereby resetting the processing conditions, and in step 408, modified processing recipe data is created. After that, the process returns to step 400, the modified processing recipe data is transmitted to the etching device, and steps 401 to 405 are executed once again. The first and second parameters are detected from the pattern data after processing obtained by executing these steps again, and these values ​​and the non-uniformity are calculated.

[0039] As shown in Fig. 14, as a result, not only the CD value but also the non-uniformity of the left-right difference of the slope could be reduced to 0.09, which is smaller than the specified value of 0.3. Since the temperature sensitivity of the CD value changes whenever the etching conditions are changed in Step 407, it is necessary to recalculate the electrode control temperature of the CD value by starting from Step 400 each time.

[0040] In addition, if the etching conditions are changed once and steps 401 to 405 are performed, and the non-uniformity of the left-right difference of the slope in step 405 cannot be reduced to within the specified value, step 407 is performed again to restart the flow. In this way, the loop of steps 400 to 405 or steps 407 and 408 is repeated until the non-uniformity in the judgment of step 405 falls within the specified value. Finally, in the processing of the actual wafer in step 406, the processing is carried out using a processing recipe in which the processing conditions based on the first parameter are modified based on the judgment using the second parameter.

[0041] In the measuring device of this embodiment, CD-SEM was used to obtain information on the three-dimensional shape, but it is acceptable to measure by directly observing the cross-sectional shape of the pattern by breaking it or exposing the cross-section using FIB, etc. Additionally, Step 404 is performed after Step 403, which calculates parameters including the first and second of the wafer for calculation, and between Step 405, which is a judgment process using the second parameter; however, if the judgment in Step 405 is determined to be outside the specified value (No), it may be performed in the process after Step 400 before modifying the recipe data for processing prior to calculating the parameters again.

[0042] In addition, in this embodiment, the left-right difference of the slope was selected as the second parameter with low temperature sensitivity; however, since it is known experimentally that sub-trench and mask erosion also have low temperature sensitivity and that in-plane uniformity can be improved by re-examining the wafer bias rather than temperature, the same applies when these are selected as the second parameter.

[0043] In addition, even for shape parameters whose temperature sensitivity is unknown, the temperature sensitivity of the parameter can be determined as shown in FIGS. 11 and 12 of the present embodiment. In that case, the temperature sensitivity of a 3D shape parameter that has a strong correlation with the feature quantity can be determined by calculating the temperature sensitivity of the feature quantity calculated from the SEM image. Since a plurality of feature quantities corresponding to the 3D shape parameter are calculated from the SEM image, the temperature sensitivity of each feature quantity can be determined, and the feature quantity with high temperature sensitivity can be selected as the first parameter, and the feature quantity with low temperature sensitivity can be selected as the second parameter.

[0044] In addition, when using a parameter that does not require further wafer processing, such as a left-right difference in slope that requires detection by CD-SEM after processing of a wafer for further calculation using the processing recipe data after correction as the second parameter, step 403 or step 404 may be selected instead of step 400 as the process returning from step 408 in the flowchart shown in FIG. 4. In this case, it is necessary to use, for example, a numerical simulation that can detect or calculate the value of the parameter as a result of processing using the processing conditions of the modified processing recipe data with a predetermined precision without using actual etching processing.

[0045] Since the first and second parameters of this embodiment were both of the same dimension as width (nm), direct comparative review was possible; however, multiple feature quantities corresponding to three-dimensional shape parameters each have different dimensions. In this case, it is necessary to perform data standardization processing using data from a reference die so that comparison can be made at the same dimension. Although CD values ​​and three-dimensional shapes were assumed as physical quantities, electrical characteristics can also be used. In that case, an electrical characteristic evaluation device is used as the measurement device, rather than a CD-SEM. Explanation of the symbols

[0046] 101: Measuring device, 102: Calculating device, 103: Etching device, 104: Wafer, 105: Wafer stage, 201: Heater, 202: Temperature controller, 203: Heater control unit, 204: Refrigerant flow path, 205: Processed wafer, 501: Top surface of wafer for output, 502: Die, 503: SEM image

Claims

Claim 1 An etching system comprising an etching device for etching a wafer, a measuring device for measuring a pattern formed on the surface of the wafer etched by the etching device, and a calculating device for providing etching conditions to the etching device, wherein the calculating device calculates a first parameter having a correlation with a temperature condition among the etching conditions higher than a predetermined reference value and a second parameter having a correlation lower than the predetermined reference value based on the measurement result of the pattern from the measuring device, calculates a temperature condition in which the first parameter becomes within an allowable range based on the calculated first parameter, determines whether the calculated second parameter is within an allowable range, and if the calculated second parameter is outside the allowable range, provides an etching condition in which conditions other than the temperature condition are changed, and if the calculated second parameter is within the allowable range, provides an etching condition in which the temperature condition is changed to the calculated temperature condition. Claim 2 An etching system according to claim 1, characterized in that the first parameter is the CD value of the pattern and the second parameter is the difference in width between the left and right sides of the cross-section of the pattern. Claim 3 An etching system according to paragraph 2, characterized in that the measuring device is a CD-SEM measuring device and acquires an SEM image from the Top View of the pattern. Claim 4 An etching system according to claim 3, characterized by calculating the difference between the CD value of the pattern and the left and right sides of the cross-section from the SEM image. Claim 5 An etching system according to claim 4, characterized in that when the difference in the left and right widths of the slopes of the cross-section of the calculated pattern is outside the allowable range, the gas is changed and the etching conditions are provided to the etching device. Claim 6 An etching method using an etching apparatus for etching a wafer, a measuring apparatus for measuring a pattern formed on the surface of a wafer etched by the etching apparatus, and a calculating apparatus for providing etching conditions to the etching apparatus, comprising: a first step of etching a wafer under provided etching conditions; a second step of measuring a pattern formed on the surface of a wafer etched in the first step; a third step of calculating, based on the measurement result of the second step, a first parameter having a correlation with a temperature condition among the etching conditions higher than a predetermined reference value and a second parameter having a correlation lower than the predetermined reference value; a fourth step of calculating a temperature condition in which the first parameter becomes within an allowable range based on the first parameter calculated in the third step; a fifth step of determining whether the second parameter calculated in the third step is within an allowable range; a sixth step of providing an etching condition to the etching apparatus in which conditions other than the temperature condition are changed when the determination of the fifth step is outside the allowable range; and when the determination of the fifth step is within the allowable range An etching method characterized by having a seventh step of providing the etching condition, which has been changed to the temperature condition calculated in the fourth step, to the etching device, and repeating the first to sixth steps until the judgment of the fifth step becomes within the allowable range when the judgment of the fifth step is outside the allowable range. Claim 7 An etching method according to claim 6, characterized in that the first parameter is the CD value of the pattern and the second parameter is the difference in width between the left and right sides of the cross-section of the pattern. Claim 8 An etching method according to claim 7, characterized in that the measuring device is a CD-SEM measuring device, and in the second step, an SEM image is acquired from the Top View of the pattern. Claim 9 An etching method according to claim 8, characterized in that, in the third step, the difference between the CD value of the pattern and the left and right sides of the cross-section is calculated from the SEM image. Claim 10 An etching method according to claim 9, characterized by providing the etching device with etching conditions in which the gas is changed in the sixth step.

Images