Etching system and etching method

Abstract

The etching system is characterized in that the etching system is provided with an etching device (103) for etching a wafer (104); a measurement device (101) that measures a pattern formed on the surface of the wafer (104) etched by the etching device (103); and a calculation device (102) for providing etching conditions to the etching device (103), the calculation device (102) calculating a first parameter having a high correlation with the temperature condition and a second parameter having a low correlation with the temperature condition among the etching conditions on the basis of the measurement result of the pattern from the measurement device (101), and calculating the temperature condition in which the first parameter is within an allowable range on the basis of the calculated first parameter. And a controller configured to determine whether the calculated second parameter is within the allowable range, provide an etching condition in which a condition other than the temperature condition is changed when the calculated second parameter is outside the allowable range, and provide an etching condition in which the temperature condition is changed to the calculated temperature condition when the calculated second parameter is within the allowable range.

Description

Technical Field

[0001] The present invention relates to an etching system and an etching method for improving the uniformity of the shape within a wafer surface. Background Art

[0002] As the structure of semiconductor devices becomes three-dimensional, the demand for manufacturing methods that can evenly form complex structures on the wafer surface is increasing year by year. In the manufacture of semiconductor devices, a target pattern is formed on the front surface of the wafer by forming a pattern mask with an exposure device and then processing it with an etching device. In addition, in order to confirm that the pattern is of the desired size, semiconductor inspection devices such as CD-SEM (Critical Dimension Scanning Electron Microscope) and OCD (Optical Critical Dimension) are generally used for measurement.

[0003] As a prior art of etching, an etching system is known, which improves the in-plane uniformity of the CD (Critical Dimension) value corresponding to the width of the top view (Top-View) of the pattern by controlling the in-plane temperature of the chip based on multiple heating elements. For example, in Patent Document 1, the following technology is described as an etching system and an etching method: etching is performed by realizing a temperature distribution of multiple heating elements determined based on the relationship between the CD shift amount and temperature of each temperature measured in advance and the CD value of the chip before processing, thereby improving the in-plane uniformity of the CD value. Here, the so-called CD shift amount represents the change in the CD value before and after etching.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2013-77859 Summary of the invention

[0007] Problems to be solved by the invention

[0008] In the above-mentioned prior art, the following points are not sufficiently considered, which leads to problems. That is, in the above-mentioned prior art, the uniformity of the CD value in the wafer surface is improved by controlling the temperature of the electrode composed of multiple heating elements. However, in recent semiconductor devices, the device structure is being three-dimensionalized, and not only the uniformity of one parameter such as the CD value is sought, but also the uniformity of multiple parameters including the cross-sectional shape is sought.

[0009] On the other hand, when considering the uniformity of multiple parameters, it is easy to think that the uniformity can be improved by controlling the electrode temperature of each parameter in the same way as in the prior art. But in fact, not all parameters are temperature sensitive. As shown in Patent Document 1, the temperature sensitivity of the CD value is high, and the uniformity of the CD value within the chip surface can be improved by adjusting the temperature of the electrodes composed of multiple heating elements that set the chip temperature. However, it is known that there are parameters with small changes caused by temperature and low temperature sensitivity. Regarding this parameter, it is found that even if etching processing is performed only by temperature control of the electrode calculated based on temperature sensitivity as in the prior art, it is difficult to improve the uniformity within the surface, and the desired shape may not be obtained.

[0010] Thus, in the prior art, it is not considered to achieve the uniformity of multiple parameters in the wafer surface including the parameter with low temperature sensitivity. The object of the present invention is to provide an etching system and an etching method that improve the processing yield by improving the uniformity of multiple parameters in the wafer surface including the parameter with low temperature sensitivity.

[0011] Means for solving problems

[0012] An etching system according to one embodiment of the present invention is characterized in that it comprises: an etching device that etches a wafer; a measuring device that measures a pattern formed on the surface of the wafer etched by the etching device; and a calculating device that provides etching conditions to the etching device, the calculating device calculating a first parameter with a high correlation with a temperature condition and a second parameter with a low correlation among the etching conditions based on the measurement result of the pattern from the measuring device, calculating a temperature condition under which the first parameter becomes within an allowable range based on the calculated first parameter, determining whether the calculated second parameter is within the allowable range, and providing etching conditions in which conditions other than the temperature condition are changed when the calculated second parameter is outside the allowable range, and providing etching conditions in which the temperature condition is changed to the calculated temperature condition when the calculated second parameter is within the allowable range.

[0013] Effects of the Invention

[0014] According to the present invention, using data measured by a measuring device, conditions other than temperature are re-examined not only for the in-plane distribution of the first parameter having temperature sensitivity, but also for the deviation of the second parameter having low temperature sensitivity, until the distribution of the first and second parameters is within the allowable range, corrections are repeatedly added to the temperature distribution corresponding to the initial target CD value, the heater is adjusted to achieve the obtained temperature distribution, and wafer processing is performed, thereby improving the processing yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram showing the device structure of a semiconductor etching system involved in an embodiment of the present invention.

[0016] Figure 2 It is a longitudinal sectional view schematically showing the structure of a wafer stage included in the semiconductor etching system according to the embodiment.

[0017] Figure 3 It is a plan view schematically showing an example of the arrangement of heater areas on the upper surface of the wafer stage according to the embodiment.

[0018] Figure 4 This is a flowchart showing the flow of operations within the computing device according to the embodiment.

[0019] Figure 5 It is a diagram schematically showing the measurement location within the wafer surface.

[0020] Figure 6 It is a schematic diagram explaining CD in a cross section and the left-right difference of a slope.

[0021] Figure 7 The following are examples of an SEM image of a line pattern of a semiconductor device, its corresponding cross-sectional schematic diagram, and the waveform of a secondary electron signal of the SEM.

[0022] Figure 8 This is an example of calculating a secondary electron signal waveform and its first-order differential waveform, which are characteristic quantities serving as a three-dimensional shape index, and a three-dimensional shape corresponding thereto.

[0023] Fig. 9 It is the value of CD as the first parameter and the left-right difference of the slope as the second parameter calculated from the SEM image.

[0024] Fig.10 This is a graph of temperature sensitivity in which CD as the first parameter and the left-right difference of the slope as the second parameter are converted into temperature.

[0025] Fig.11 This is a diagram for explaining a method of calculating the temperature of each electrode to obtain a uniform parameter value within a surface from a temperature sensitivity graph.

[0026] Fig.12 This is a graph illustrating a state where the temperature sensitivity is low.

[0027] Fig.13 This is a graph showing the reduction in the variation of the CD value and the variation in the left and right differences of the slope due to temperature control.

[0028] Fig.14 This is a graph showing the reduction in the deviation of the left-right difference of the slope due to the change in the gas type. DETAILED DESCRIPTION

[0029] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the present invention is not limited by the embodiments, and in the description of the accompanying drawings, the same parts are marked with the same reference numerals and shown. When there are multiple components with the same or similar functions, different subscripts are sometimes added to the same reference numerals for description. In addition, when there is no need to distinguish these multiple components, the subscripts are sometimes omitted for description. The position, size, shape, range, etc. of each component shown in the accompanying drawings are sometimes not shown in order to facilitate the understanding of the invention. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the accompanying drawings.

[0030] [Example 1]

[0031] First, use Figure 1 To illustrate an embodiment of the present invention. Figure 1 1 is a schematic diagram showing the structure of a semiconductor etching system according to an embodiment of the present invention. In this figure, the overall structure of the semiconductor etching system is schematically shown, and a processing device for a semiconductor wafer such as an etching processing device is shown, which is used to process the semiconductor wafer to achieve the distribution of a specific physical quantity in the in-plane direction of the wafer (for example, the shape or size of a pattern for a circuit formed on the surface of the wafer).

[0032] The semiconductor etching system of this embodiment includes an etching device 103, a measuring device 101 and a computing device 102, wherein the etching device 103 includes a chip carrier 105 in a container of the etching device 103, the chip carrier 105 is provided with a chip 104, and has a function of variably adjusting the distribution of the temperature in the in-plane direction of the chip 104, the measuring device 101 can measure the distribution of specific physical quantities within the chip surface, and the computing device 102 has: a computer that calculates multiple parameter values ​​including CD values ​​obtained based on the results of measuring a pattern formed on the surface of the chip at multiple predetermined positions by the measuring device 101, and calculates the temperatures of multiple parts of the chip or the carrier supporting it using the parameter values; and a mechanism for determining whether the deviation of the parameters is within an allowable range.

[0033] Figure 2 1 is a cross-sectional view schematically showing the structure of the wafer stage and temperature control of the etching device involved in the embodiment. The wafer stage 105 has a plurality of heaters 201 for heating and a refrigerant flow path 204 for cooling below the surface on which the processing wafer 205 is loaded. The temperature distribution in the in-plane direction of the wafer stage 105 is adjusted by adjusting the heat generation of the plurality of heaters 201 and adjusting the temperature of the refrigerant. The plurality of heaters 201 are provided for each area of ​​the wafer stage 105, and the areas are divided into Figure 3 The method of dividing into concentric circles as in (a), Figure 3 The divided area is called an electrode. The number and size of the divisions are not limited to the example. In addition, 202 is a temperature regulator of the electrode of the heater. Although not shown in the figure, it uses the sensor values ​​obtained from the plurality of temperature sensors provided on the electrode of the heater to adjust so that the temperature of the upper surface of the stage on which the wafer is loaded becomes the wafer temperature calculated by the calculation device 102. The control of this adjustment is performed by the heater control unit 203.

[0034] The coolant flow path 204 circulates and flows between the coolant temperature controller connected via a pipe not shown in the figure, and is adjusted to a temperature within a predetermined range in the coolant temperature controller. In the figure, the coolant flow path 204 is arranged below the heater 201, but it can also be arranged above. In addition, in the case where the chip temperature can be adjusted to a desired value only by the heater 201, the coolant may not be used.

[0035] The calculation device 102 is a device that provides etching conditions that can achieve uniformity of CD value and shape within the wafer surface before the wafer is actually etched, calculates the stage temperature used for this, and transmits it to the etching device 103. Figure 4 The flowchart performed in the calculation device is shown. In this embodiment, the etching process is first performed using a calculation wafer. The so-called calculation wafer is another wafer that is pre-processed to detect and determine the parameters required for the above-mentioned processing conditions in order to obtain processing conditions that can make the CD value, shape, and size distribution of the film structure on the processed wafer in the in-plane direction within the desired range before etching the wafer (real wafer) used to manufacture semiconductor devices (devices). The wafer is at least pre-configured on the upper surface with a film structure and pattern that is the same as or regarded as the same degree as the film structure and pattern of multiple film layers including the film to be processed configured on the upper surface of the real wafer.

[0036] In the initial step 400, the computing device 102 obtains a data packet including Figure 1 The etching device 103 shown in the figure calculates the flow rate of the processing gas when processing the calculation wafer, the pressure in the processing chamber, the temperature of the wafer being processed and the distribution thereof, and other processing conditions, which are called the processing recipe, and represents the operation of the etching device 103 (processing recipe data), and records them in an internal storage device. Next, in step 401, the calculation wafer is used to perform etching processing based on the obtained processing recipe data. In this embodiment, a plurality of calculation wafers are processed based on different temperature conditions.

[0037] As also described in Patent Document 1, it is known that the CD value has temperature sensitivity and becomes a different value depending on the temperature. Accordingly, in step 401, a temperature sensitivity process for calculating the desired pattern is performed by changing the temperature of a plurality of calculation wafers. In this embodiment, under the condition that the wafer temperature during the process is set to 10°C and 50°C in the in-plane direction, and in particular, under the condition that the temperature detected at each of the plurality of locations of the wafer or the wafer stage during the process is set to a given allowable range, etching processing is performed on each of two calculation wafers, and CD values ​​and their distribution are detected from these calculation wafers.

[0038] Next, in step 402, the processed multiple calculation wafers are measured. In this embodiment, the CD value of the pattern is measured using a CD-SEM device that is generally used in the past. This is to enable non-destructive and high-speed measurement. In this embodiment, for multiple predetermined locations on the upper surface 501 of each calculation wafer, the desired pattern of the location is obtained from the top view using a CD-SEM device. At this time, it is possible to calculate Figure 5 The distribution of the measured values ​​in the in-plane direction obtained for the plurality of locations on the upper surface 501 of the calculation wafer is obtained in this way. From the bare die 502 on which each device pattern is formed on the upper surface 501 of the calculation wafer corresponding to each semiconductor device (chip) finally cut out from the wafer, the processed shapes of each location formed inside of each of the plurality of predetermined bare dies are measured to obtain SEM images 503a, 503b, ...

[0039] A CD-SEM image is an image in which secondary electrons excited from atoms by scattering of incident electrons in a sample are detected in an SEM, and is displayed in shades (brightness) for each pixel of the image. It characterizes 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 of the surface of a calculation wafer etched at a wafer temperature of 10°C and multiple images of a calculation wafer etched at 50°C are obtained. Images are obtained for patterns at specific locations inside the respective regions of the 110 bare chips 502 formed on the upper surface 501 of each calculation wafer.

[0040] In addition, the parts for detecting the temperature of the chip or chip carrier in this embodiment are arranged below the area of ​​each heater 201 whose output or heating amount is adjusted by the electrode control device so that the temperature outside the window becomes the desired value, and are arranged in the projection plane observed from above them, and the number of these parts is the same as the number of heaters 201 or greater than the number of heaters 201. In the case where the chip temperature is set to a given value with respect to the in-plane direction as in steps 400 and 401, the output and heating amount of each heater 201 can also be adjusted for the set of temperature values ​​detected at multiple parts so that the deviation of each value is within the desired range. Figure 3 In the example of the heater 201 having a rectangular area shown in (b), the size of each heater is smaller than the size of each bare chip 502. In this example, each heater 201 is adjusted based on the temperature detected at a larger number of locations than the number of bare chips 502.

[0041] Next, in step 403, shape parameters showing a three-dimensional shape are calculated based on the obtained CD-SEM image. As the first parameter, a parameter with high temperature sensitivity, such as a CD value, is calculated, and as the second parameter, a parameter with low temperature sensitivity, that is, a parameter with low correlation with the wafer temperature and high correlation with other processing conditions other than temperature, such as the left and right difference of the slope of the cross section that can be experimentally confirmed to have low temperature sensitivity, is calculated. In addition, in the present invention, the parameter with low correlation with temperature also includes a parameter without correlation with temperature.

[0042] like Figure 6 As shown, the CD value is a value that represents the width of the cross section, and the left-right difference of the slope is the difference in width of the left-right slope of the pattern cross section |S1-S2|. When patterning is performed by SADP (Self-Aligned Double Patterning), the uniformity of this parameter in the wafer surface becomes important.

[0043] Here, we will explain the SEM image and the method of calculating parameters based on the image. Figure 7 An example of a SEM image of a line pattern of a semiconductor device is shown in FIG. Figure 7 (a) is a two-dimensional SEM image as a top view of a line pattern. In this SEM image, there is one line pattern extending in the Y direction in the XY plane of the diagram corresponding to the wafer surface. In this image, each pixel has a shade (brightness).

[0044] Figure 7 (b) is Figure 7 An example of the cross-sectional shape of the pattern at the position indicated by AB in (a) corresponds to the XZ cross section. Figure 7 (c) is related to Figure 7An example of a secondary electron signal waveform of an SEM corresponding to the lightness and darkness of the image 701 (a) and the cross-sectional shape (b). This waveform is also called a line profile. This signal waveform is highly sensitive to the inclination angle of the cross section of the pattern to be measured, and the signal amount at the side wall portion of the pattern is larger than the signal amount at the flat portion of the pattern. Figure 7 The inclined surface 702 of the cross-sectional shape of (b) roughly corresponds to 704 of the signal waveform of (c), and the flat portions 703 and 705 roughly correspond to each other. Thus, it can be seen that the signal waveform changes according to the cross-sectional shape of the pattern.

[0045] On the other hand, the characteristic quantity used to estimate the cross-sectional shape can be calculated based on the signal waveform. The so-called characteristic quantity refers to the peak value, width, etc. obtained from the waveform of the secondary electron signal and its first differential waveform and second differential waveform. It is a shape index that characterizes the characteristics of the shape of the pattern. Figure 8 An example of a characteristic quantity is shown. (a) represents the waveform of a secondary electron signal, (b) represents its first differential waveform, and (c) represents the cross-sectional shape of a pattern. The value of the width of the waveform indicated by the arrow is called a characteristic quantity, and the shape of the pattern width (801, 804), curling (802, 805), and side radial angle (803, 806) as the measurement object can be captured from the relationship between these multiple characteristic quantities.

[0046] In this embodiment, Fig. 9 The CD value as the first parameter and the left-right difference of the slope as the second parameter obtained from the SEM image by this calculation method are shown. (a) is the CD value of the first parameter, and (b) is the left-right difference of the slope of the second parameter. The white circle indicates that the temperature condition when the calculation wafer is processed is 10°C, and the black circle indicates that it is 50°C. The horizontal axis of the graph indicates the 110 points measured for each wafer that was etched.

[0047] Next, these are transformed into a temperature sensitivity graph with the horizontal axis being temperature, and the initial deviation σi ( Fig.10 ). In this embodiment, the values ​​of the first and second parameters after coordinate transformation from the CD-SEM measurement coordinates to the electrode coordinates of the etching device are used. The initial deviation (standard deviation) of the CD value of the first parameter for 10°C wafers is σCD(10deg)=0.91, and the deviation for 50°C wafers is σCD(50deg)=0.76. Regarding the deviation of the left and right difference of the slope of the second parameter, the 10°C wafer is σS(10deg)=0.16, and the 50°C wafer is σS(50deg)=0.08.

[0048] Next, in Figure 4 In step 404 of the process, the electrode control temperature of the first parameter (CD value) is calculated. Fig.11The following is a method for calculating the temperature of each electrode for setting a parameter value uniform within the surface from a temperature sensitivity chart. For illustration, in (a), only electrode numbers R1 (○) and R2 (Δ) are used to plot the CD values ​​obtained by measuring the calculation wafer etched at temperatures T1 and T2 using CD-SEM, and the dotted line is the first-order straight line approximation line for each electrode. Based on the first-order straight line approximation line, the temperature of each electrode for setting the target CD value shown in the chart is calculated. That is, as shown by the arrow, the temperature T of electrode R1 is obtained based on the intersection of the first-order straight line approximation line of electrode R1 and the target. R 1. Calculate the temperature T of electrode R2 from the intersection point with the first-order straight line approximation line of electrode R2 R 2.

[0049] In addition, as in (b), when the chip processing is calculated at multiple temperatures other than T1 and T2, such as T3, T4, etc., and there are multiple data, it is not approximated by a first-order straight line approximation line, but approximated by a second-order curve approximation line as shown by the dotted line in (b).

[0050] Here, the parameters with low temperature sensitivity are explained. The electrode is a part of the etching device and has a range of controllable temperatures. For example, if the minimum temperature is set to Tmin and the maximum temperature is set to Tmax, the wafer processing temperatures T1 and T2 are usually calculated to be within the range of Tmin and Tmax. Fig.11 The calculated temperature T R 1. T R2 Also within the range of Tmin and Tmax. On the other hand, Fig.12 When the gradient due to temperature is small, the temperature T obtained from the intersection of the approximate line of each electrode and the target value is R1 , T R2 The temperature becomes outside the range of Tmin and Tmax. In this case, the electrode temperature cannot be achieved. In addition, such a small inclination means that even if the temperature is changed between Tmin and Tmax, the change in the parameter value is small, and the temperature sensitivity is small.

[0051] As Figure 4 The next step 405 of the process is a process for determining whether the deviation of the second parameter (left and right difference of the slope) with low temperature sensitivity is within a given allowable range. When the deviation is within the specified value (yes), for the shape processed by the etching process based on the initial processing recipe data including the temperature condition, it is determined that the deviation of the first parameter (CD value) and the second parameter calculated in step 404 is a value within a given allowable range required for the semiconductor device or its manufacturing, and the process is transferred to the next step 406, which is a process for processing the actual wafer used for semiconductor device manufacturing.

[0052] On the other hand, when the deviation of the second parameter is out of the specified value (No), for example, even if the deviation of the first parameter (CD value) is within the allowable range by temperature control in accordance with the initial processing recipe data, a problem may occur in the semiconductor device or its manufacturing in terms of the second parameter (the left and right difference of the slope). In this case, the process is transferred to the process after step 407, and the processing recipe data is modified to change the conditions of the wafer processing that are highly correlated with the parameter so that the deviation of the second parameter becomes a value within the allowable range.

[0053] Specifically, when using Fig.10 In the case of data, the initial deviations σCD(10deg) and σCD(50deg) of the CD value obtained by processing the calculation wafer under the temperature conditions of 10°C and 50°C, respectively, contained in the processing recipe data as initial values, are calculated, and these values ​​are compared with the upper limit value of the allowable range of the deviation of the CD value. In the case where it is determined that the value of the deviation is outside the allowable range with the upper limit value as the threshold, in order to make the deviation of the CD value a value within the allowable range, the calculation device calculates the values ​​of the temperatures to be set at the above-mentioned multiple locations of the detected temperature and their distribution. The set of the set values ​​of the temperatures at the above-mentioned multiple locations in the processing set as such a processing condition is taken as a temperature group, and the heater 201 is adjusted so as to become these temperatures under the processing condition of the temperature group T3 group corrected to increase the deviation of the CD value, and the calculation wafer is processed, and the deviation σCD(T3 group) as the result of the processing becomes Fig.13 As shown in (a).

[0054] On the other hand, the deviations σS(10deg) and σS(50deg) of the left and right differences of the slope are plotted in Fig.13 (b) shows that if the specified value of the deviation is set to σ = 0.3, the deviation of the left and right differences of the slope is within the specified value (yes). In the case of this data, since both the deviation of the CD value after temperature control and the deviation of the left and right differences of the slope can be suppressed within the specified value, it can be seen that the actual wafer processing based on the processing recipe data with the temperature group T3 as the processing condition can be promoted.

[0055] On the other hand, when the deviation of the second parameter is out of the specified value (No), even if the deviation of the first parameter (CD value) is brought into the specified value by temperature control, the second parameter (the left and right difference of the slope) will not be brought into the specified value, and therefore, the deviation of the two parameters cannot be brought into the specification. In this case, in this embodiment, in order to reduce the deviation of the left and right difference of the slope, the etching process conditions other than the temperature are re-examined and the conditions are set again. This step becomes Figure 4 Step 407.

[0056] exist Fig.14 In the case of the other experimental examples shown, the deviation of the left and right difference of the slope of the calculated wafer after processing is greater than the specified value when arbitrary temperature groups T2 and T3 are used as processing conditions, and the deviation cannot be reduced even if the temperature is changed. In the case of this example, in step 407, the type of gas is changed, and the temperature condition is changed to the temperature group T3, and the new processing conditions are reset, and the corrected processing recipe data is prepared in step 408. After that, the process returns to step 400, the corrected processing recipe data is sent to the etching device, and steps 401 to 405 are executed again. The first and second parameters are detected from the processed pattern data obtained by executing these steps again, and these values ​​and the deviation are calculated.

[0057] like Fig.14 As shown in FIG. 4 , as a result, not only the CD value can be reduced, but also the deviation of the left and right difference of the slope can be reduced to 0.09 which is less than the specified value of 0.3. Since the temperature sensitivity of the CD value changes every time the etching conditions are changed in step 407, it is necessary to recalculate the electrode control temperature of the CD value every time from step 400.

[0058] Furthermore, when the etching conditions are changed once and steps 401 to 405 are performed, if the deviation of the left and right difference of the slope cannot be made within the specified value in step 405, step 407 is performed again to re-execute the flow. In this way, the loop of steps 400 to 405 or steps 407 and 408 is repeated until the deviation is within the specified value in the determination of step 405. Finally, in the processing of the real wafer in step 406, based on the determination using the second parameter, the processing recipe is added to the processing conditions based on the first parameter to perform the processing.

[0059] In the measuring device of this embodiment, CD-SEM is used to obtain information on the three-dimensional shape, but a method may also be used in which a cross section is made by cutting or FIB, and the cross-sectional shape of the pattern is directly observed for measurement. In addition, step 404 is performed after step 403 in which the parameters including the first and second parameters of the calculation wafer are calculated, and between step 405, which is a process of determination using the second parameter, but when the determination in step 405 is determined to be outside the prescribed value (no), it may be performed in the process after step 400, before the correction of the processing recipe data before the parameters are calculated again.

[0060] Furthermore, in this embodiment, the left and right differences in the slope are selected as the second parameter with low temperature sensitivity. However, in experiments, the temperature sensitivity of the sub-grooves and mask erosion is also low. It can be seen that the in-plane uniformity can be improved by re-examining the chip bias instead of the temperature. Therefore, the same is true when these are selected as the second parameter.

[0061] Furthermore, even if the shape parameters of the temperature sensitivity are unknown, the Fig.11 as well as Fig.12 In this case, by calculating the temperature sensitivity of the feature quantity calculated from the SEM image, the temperature sensitivity of the three-dimensional shape parameter having a strong correlation with the feature quantity is known. Since a plurality of feature quantities corresponding to the three-dimensional shape parameter are calculated from the SEM image, the temperature sensitivity of each feature quantity can be confirmed, and the feature quantity with high temperature sensitivity is selected as the first parameter, and the feature quantity with low temperature sensitivity is selected as the second parameter.

[0062] In addition, when the following parameters are used as the second parameter, Figure 4 In the process of returning from step 408 in the flowchart shown, step 403 or step 404 may be selected instead of step 400, wherein the above-mentioned parameter is not the left and right difference of the slope after the wafer processing which needs to be detected by CD-SEM, but a parameter which does not require the wafer processing again, which is calculated again using the corrected processing recipe data. In this case, for example, it is necessary to use numerical simulation which can detect or calculate the value of the parameter as the result of the processing condition using the corrected processing recipe data with a given accuracy without using the actual etching processing.

[0063] The first parameter and the second parameter of this embodiment are both width (nm), which is the same dimension, so they can be directly compared and studied, but the dimensions of the multiple feature quantities corresponding to the three-dimensional shape parameters are different. In this case, in order to be able to compare in the same dimension, it is necessary to use the data of the reference bare chip to standardize the data. CD value and three-dimensional shape are conceived as physical quantities, but electrical characteristics can also be used. In this case, instead of CD-SEM, an electrical characteristic evaluation device is used as a measuring device.

[0064] Description of Reference Numerals

[0065] 101: measuring device, 102: calculating device, 103: etching device, 104: chip, 105: chip stage, 201: heater, 202: temperature regulator, 203: heater control unit, 204: coolant flow path, 205: processing chip, 501: upper surface of the chip for calculation, 502: bare chip, 503: SEM image.

Claims

1. An etching system, characterized in that: have: an etching device for etching the wafer; a measuring device that measures a pattern formed on the surface of the wafer etched by the etching device; and a computing device that provides etching conditions to the etching device, The calculation device calculates a first parameter having a high correlation with a temperature condition and a second parameter having a low correlation among etching conditions based on the measurement result of the pattern from the measurement device, calculates a temperature condition under which the first parameter falls within an allowable range based on the calculated first parameter, and determines whether the calculated second parameter falls within the allowable range. When the calculated second parameter is outside the allowable range, etching conditions with conditions other than the temperature condition changed are provided, and when the calculated second parameter is within the allowable range, etching conditions with the temperature condition changed to the calculated temperature condition are provided.

2. The etching system according to claim 1, wherein: The first parameter is a CD value of the pattern, and the second parameter is a difference between left and right widths of a slope of a cross section of the pattern.

3. The etching system according to claim 2, wherein: The measuring device is a CD-SEM measuring device, and a SEM image from a top view of the pattern is obtained.

4. The etching system according to claim 3, wherein: The CD value of the pattern and the difference between the left and right widths of the inclined surface of the cross section were calculated from the SEM image.

5. The etching system according to claim 4, wherein: When the calculated difference between the left and right widths of the inclined surface of the cross section of the pattern is outside the allowable range, etching conditions in which the gas is changed are provided to the etching device.

6. An etching method using the following apparatus: an etching device for etching the wafer; a measuring device that measures a pattern formed on the surface of the wafer etched by the etching device; and a computing device that provides etching conditions to the etching device, The etching method is characterized by having: Step 1, etching the wafer under provided etching conditions; Step 2, measuring a pattern formed on the surface of the wafer etched in the first step; A third step of calculating a first parameter having a high correlation with the temperature condition and a second parameter having a low correlation with the temperature condition among the etching conditions based on the measurement result of the second step; A fourth step of calculating a temperature condition under which the first parameter falls within an allowable range based on the first parameter calculated in the third step; Step 5, determining whether the second parameter calculated in step 3 is within an allowable range; Step 6, when the determination in step 5 is outside the permissible range, providing the etching condition with the conditions other than the temperature condition changed to the etching device; and In step 7, when the determination in step 5 is within the permissible range, the etching condition changed to the temperature condition calculated in step 4 is provided to the etching device. When the determination in the fifth step is outside the permissible range, the first to sixth steps are repeated until the determination in the fifth step is within the permissible range.

7. The etching method according to claim 6, wherein: The first parameter is a CD value of the pattern, and the second parameter is a difference between left and right widths of a slope of a cross section of the pattern.

8. The etching method according to claim 7, wherein: The measuring device is a CD-SEM measuring device, and in the second step, a SEM image of the pattern viewed from the top is acquired.

9. The etching method according to claim 8, wherein: In the third step, the CD value of the pattern and the difference between the left and right widths of the inclined surface of the cross section are calculated based on the SEM image.

10. The etching method according to claim 9, wherein: In the sixth step, the etching conditions of the changed gas are provided to the etching device.

Images