JP2910924B2 - Method for monitoring the end point trace of a plasma etching reactor - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to automated quality control and process operation techniques, and more particularly to an improved method and apparatus for detecting anomalies during manufacturing process operation. It is.

[Conventional technology and its problems]

In the manufacture of semiconductor devices, a number of steps are combined in the processing of individual semiconductor devices. During the manufacture of such semiconductor devices, various attempts have been made to establish quality control inspections in various processes. In general, these systems for quality control checks (quality control inspections) include methods of physically inspecting or testing selected samples in these semiconductor devices at various stages during the manufacturing process. . However, such systems are cumbersome and relatively expensive. Further, in many cases, the quality of each manufactured device cannot be guaranteed because these systems are applied only to devices arbitrarily selected from the manufacturing process. Furthermore, systems that have been developed are operative to detect problems in the manufacturing process at a point in time after an error has already occurred. As a result, there is a disadvantage that the same error is repeatedly generated during a specific process operation for a large number of semiconductor devices before this error is detected in a later quality control inspection. As is apparent from an economic point of view, there is a demand for a manufacturing method for detecting an abnormality in a manufacturing process as soon as possible after these abnormalities occur. Further, it is desirable that these abnormalities can be detected in real time. In other words, it is desirable that the abnormality can be detected at the time of occurrence. By utilizing such instantaneous detection, it is possible to prevent the same process abnormality from being repeated for a semiconductor device during manufacturing.

A common process operation in the manufacture of semiconductor devices is plasma etching. In this plasma etching, a semiconductor device in the form of "slice", which is a common name, is arranged in an etching chamber by interposing a specific gas and supplying RF (high frequency) power under a predetermined pressure and temperature. Let it. During the etching process, certain materials on the surface of the semiconductor slice react with the gases in the chamber and then evaporate from the slice surface. A typical etching process for a slice is one that lasts within one minute or up to several minutes or more.

Typical conventional etching reactors are provided with equipment for monitoring specific items of the etching process. The reactors are provided with equipment for performing on-line hardware monitoring, for example, equipment for monitoring reactor temperature and pressure, RF power supply, and feed gas flow rates.

Further, the conventional etching apparatus is also provided with an apparatus designed to detect the end point of the etching operation. Solid State Technology disclosed herein for reference,
April 1981, pp. 115-122, "Method for Detecting the End of Plasma Etching (Paul J. Marcoux and Pang Dow F.
oo) have proposed several methods for such devices. These proposed methods use emission spectroscopy, optical reflection, mass spectrometry, impedance monitoring, Langmuir probe monitoring and pressure monitoring. Regardless of which monitoring method is used, the endpoint monitor works to detect the end (completion) of the desired etching reaction, so that the etch cycle terminates this etch cycle and furthermore, the etching of the unprocessed slice is terminated. Notify that preparation is complete.

A frequently used method for detecting the end point uses an end point trace (abbreviated as EPT). The EPT is realized by emission spectroscopy and is used to measure the concentration of gas in plasma over the surface of a slice to be etched. This EP
T is designed to monitor the reactants or products of the etching reaction. For example, by adjusting the EPT so that these gases, which are the desired etching products, can be measured, the monitoring device can detect when these etching products are no longer released into the plasma,
Thereby, the end point of the desired etching reaction can be notified. In general, endpoint detectors are designed to find abrupt changes to the etching process at the concentration of the species being monitored and to detect the approximate time at which this endpoint is expected. This device is beneficial in the following respects.
That is, a signal for shifting to the end of the etching cycle is supplied to the etching apparatus, the etched semiconductor slice is removed, and a new (unprocessed) semiconductor slice is inserted into the etching chamber.

However, these endpoint detectors, whether applied or merely theoretical, have several limitations. As a basic limitation, these detectors serve only to detect the end of the etching operation. The disadvantage is that these detectors do not provide any information as to whether the etching process is continuing at its best or if an anomaly has occurred during this process.

There is a need for a process or apparatus that can determine whether an etching process is in progress or completed at its best. An etching monitoring system capable of automatically checking the etching state of all slices can solve the above-mentioned various problems in recent quality control systems for semiconductor manufacturing. Further, a system that can monitor an etching process before an etching operation in a state where information to know whether or not a layer formed on a semiconductor device has been formed and processed in a predetermined manner can be obtained. There are further advantages.

Conventional equipment and processes have not been able to achieve the desired benefits described above.

A pending patent application (US Patent Application No. 046,497, filed May 4, 1987, later filed) assigned to the assignee of the present application contains abnormalities during cyclically repeated process operations. A method and apparatus for detecting is disclosed. The specific invention in this application relates to a plasma etching process in manufacturing a semiconductor device. According to an embodiment of the present invention, the actual endpoint trace (EPT) for each semiconductor slice etch.
Is compared with the predetermined standard EPT in detail,
Not only does it determine if the etch is in progress as expected, but it also determines if certain operations have been properly performed on the slice prior to etching.

[Object of the invention]

The present invention aims to improve the method and apparatus disclosed in the related invention described above.

[Summary of the Invention]

According to the present invention, an improved method and apparatus for detecting anomalies in cyclical, ie, repetitive, process operations can be provided. A specific application example of the present invention is a plasma etching process in manufacturing a semiconductor device. Furthermore, according to one embodiment of the present invention applied to the endpoint trace data, the actual endpoint trace data for the etching of the semiconductor slice and the predetermined reference endpoint trace for the particular etching process to be performed. An improved analysis between the two is obtained. In accordance with the practice of the present invention, often the analysis of this endpoint trace data
It has been found that a substantial cause of the detected abnormality in the etching reaction can be estimated. According to the present invention,
Analysis of this endpoint data can provide valuable information relating to the layer of material formed on the semiconductor device prior to the etching process.

According to one embodiment of the present invention, combined with plasma etching, the etching proceeds as predetermined by comparing the actual endpoint trace for the etching of each slice with the predetermined reference EPT in detail. Not only can it be determined whether or not a given operation has been properly performed on the slice prior to etching. For example, according to the present invention, analyzing the condition of locations where deposition is excessively thick or thin, where photolithography steps have been omitted, or where inaccurately performed certain features are still enclosed Can be.

According to the embodiment described above, a reference EPT is first defined. The reference EPT is divided into a plurality of regions, each of which has significance with respect to a corresponding connection point or step during the etching process. Real
EPT is obtained during the etching of each of the semiconductor slices. The actual EPT is divided into a plurality of regions on the basis of a change in the inclination point of the EPT. Apply a series of hands-on features to the EPT relative to the area of the actual endpoint trace
To match the area. This is based on the characteristics of the desired matching (matching) area of the actual EPT and the reference EP to be matched.
It is performed by comparing the characteristics of the region of T.
When each of the actual EPT regions is matched with the reference EPT region, a predetermined characteristic of each region is compared with a characteristic of the corresponding region of the reference EPT. Such a comparison is made by executing a set of rules adapted to the particular process to be monitored. These rules are called "process specific" rules. These process-specific rules invoke a set of rules that compare the general set of characteristics of any two regions. These latter rules are called process independent rules. By comparing the area of the actual EPT with the area of the reference EPT, the system can prove when an abnormality occurred during the etching operation. By analyzing the area in detail and applying process specific rules, the cause for the proven anomaly can be inferred by the system.

ADVANTAGE OF THE INVENTION According to this invention, there exists an advantage which can provide the system which has the ability to compare and analyze the continuously variable data curve with the continuously variable data curve.

According to certain advantages of the present invention, it is possible to tolerate changes in the shape or duration of a particular region of a particular data curve, as well as to establish predefined regions of the actual data curve, Can be compared to the corresponding area of the reference curve. This is a more particular advantage for various reasons. That is, the duration of one or more regions of the actual data curve varies significantly from curve to curve. To accurately analyze each of the actual data curves, first accurately identify the starting and ending points,
Accurately determining the duration of each region of the curve is extremely important.

In addition, it is an advantage of the present invention that it defines and compares regions of the curve that can be continuously varied, and which regions of the actual data curve can not only "extend" the duration, but also "float" over time. "You can. For example, if the initial region of the data curve is of excessively long duration,
With the present invention, there is the advantage that such an extended duration can be tolerated, while still demonstrating the boundaries of continuous regions in the data curve.

Still further, according to an advantage of the present invention, the system of the present invention is standardized, so that the system of the present invention can be easily and quickly applied to change an etching or manufacturing operation.

(Example of the invention)

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

As described above, according to the present invention, it is possible to provide an improved method and apparatus for detecting an abnormality in a repetitive type process (processing) operation.

Applying the present invention to such repetitive process operations, such operations can be monitored by the device,
A continuously variable electrical signal which correlates to the progress of the process to be monitored or
EPT is obtained. One type of such continuously variable signal utilized in the present invention is time based. That is, this signal changes with time. Also, this signal is one of the intensity that changes with time. Such signals can often be divided into regions, which correspond to steps or parts of the process to be performed. It is also important that this signal can be defined as a preferred or reference signal. Here, the reference signal represents a signal obtained when the process proceeds in a suitable state.
Thus, the actual signal received during the process operation can be matched to the characteristics of the reference signal.

In the present invention, the reference curve is defined as follows. That is, this curve corresponds to the expected continuously variable signal when the sensing device is monitoring the process. During the process operation, the actual curve is obtained, thereby representing the output of the sensing device. During or after the process cycle, the area of the actual curve is matched against the corresponding area of the reference curve, so that the actual curve determines whether the process is in progress or has been in good condition Or whether an abnormality has occurred during the process. The characteristics of each region of the actual curve compared to each region of the reference curve will vary from region to region, which characteristics are determined by process and data considerations for the particular process step to which the region corresponds. Is what is done.

The results of the comparison of the actual and reference curves can be used in various ways. For example, sending a signal to the processing equipment to continue the process operation, sending a signal to the processing equipment to inhibit this operation, sending a signal to the operator of this equipment, a specific process cycle for later use. Storing information about the process, sending signals to the processing equipment to modify the process during or after a process cycle, or pointing out specific anomalies or analyzing the causes of detected anomalies. There is a way.

The above-mentioned pending patent application No. 046,497 discloses a method and apparatus for detecting anomalies in a cyclically repeated process operation. This patent application describes a system for defining a reference curve and its area for a particular process. In addition, the actual curve representing the data from this process is obtained during the process and compared to a reference curve, thereby determining if an anomaly has occurred or has occurred during the process to be monitored. This application also describes the use of this system to cooperate with plasma etching during process operation. According to this system, while analyzing the actual curve, the area of this curve is defined as a function of time from the start of the process operation.

According to the present invention, an improved process and apparatus for comparing a reference continuously variable curve with an actual continuously variable curve can be provided. The present invention encompasses an improved method of defining the regions in the actual curve so that these regions can be defined more accurately and their analysis results more accurate. According to the present invention,
An improved method using a practical set of functions is obtained, whereby the area of the actual curve can be defined and matched to the area of the reference curve. This gives an accurate definition and analysis of the area of the actual curve. Also, the present invention can be modularized,
In addition, a set of process-independent rules as well as a set of process-specific rules can be used for the analysis. As a result, the system of the present invention is particularly well and easily adaptable to different and changing etching processes or other manufacturing processes.

According to one embodiment of the present invention, it has been found that it is suitable for application in combination with a semiconductor manufacturing process, particularly a plasma etching process. Hereinafter, with reference to FIGS.
An example in which one embodiment of the present invention is applied to a plasma etching operation will be described.

First, FIG. 1 is a conceptual diagram showing a typical plasma etching reactor used in cooperation with one embodiment of the present invention. This reactor contains a plasma etching reaction vessel 10
A shower head electrode 12 is
Is installed. This showerhead electrode is connected to the RF power supply 14
Electrostatically. Generally this power supply 14
Supply 3.5MHz high frequency power. The RF power supply 14 is provided with an RF tuning network not shown in FIG. Holes 16 are formed in the electrode 12 from which gases are released and are supplied to the electrode 12 via gas lines 18. The flow rate of this gas is controlled by a mass controller not shown in FIG. A semiconductor slice 20 to be etched is placed on a substrate 22 of a reactor.
22 is grounded as shown at 24. The reactor is also provided with a pressure regulator 26 and a gas outlet line 28, which is operatively connected to a vacuum tube not shown in FIG.

In the operation of the plasma etching reactor, a mixture of gases is supplied via electrode 12 and power is supplied from RF power supply 14 via this electrode. A low-pressure glow discharge is established, and reactive species are generated in the plasma 30. These reactive species selectively react with the thin film of material on the slice 20 to obtain a product that evaporates from the slice 20 and ultimately the product is pumped through the gas outlet line 28 Will be issued. Such an etching operation is continued, if the etching is successful, until a predetermined amount or depth of the desired material has been etched from the surface of slice 20.

EPT is obtained by emission spectroscopy from the etching reactor used in the embodiment of the present invention shown in FIG. This E
The PT detector can detect light emitted by electronically excited species in the plasma. The light emitted by atoms, molecules or free radicals in an unbalanced plasma is not strictly proportional to the density of these species, but for the purposes of this EPT, it is assumed that proportional properties are retained. Can be assumed. By installing a detection device, it is possible to monitor the concentration (density) of the etching reaction product, that is, the reactive species in the plasma. Once it has been determined which etch product or species is to be detected, the system can be set to monitor the wavelength of light corresponding to the light emitted by the species to be monitored. According to the present example, the system is designed to detect light emitted by a particular etching product.

Returning again to FIG. 1, EPT for processing etchers
Also shown is an apparatus for obtaining The plasma etching reaction vessel 10 is provided with a window 32 through which light emitted from the plasma passes. Light from this window passes through the optical filter. The filter 34 blocks light outside the radiation band selected in advance. According to the present embodiment, since the apparatus is set to monitor carbon monoxide, the filter 34 allows light in an optical band of about 520 [nm] to pass. Light emitted from the plasma 30 passes through the window 32 and, if the wavelength is appropriate, passes through the optical filter 34 and reaches the photodiode 35. An electric signal corresponding to the intensity of light impinging on the photodiode 36 is generated from the photodiode 36 and supplied to the EPT recorder 38. In a typical prior art plasma etching reactor, the EPT trace recorder 38 provides a chart-based record of the EPT trace of the etching operations performed in the reactor.

One of the desired reactions in this example is the etching of CF ₄ and silicon dioxide: SiO ₂ + CF ₃ ===> SiF ₄ + CO.

The production of this CO, and thus its spectral intensity at the plasma, decreases when all of the SiO ₂ is etched from the slice, and the above reaction stops and further
Generate CO. Thus, a decrease in the CO line intensity, ie, a point at which this end point can be predicted, indicates that the layer has been etched (ie, that the end point has been reached).

FIG. 1 shows a digital processor or computer 40, which is operatively connected to a photodiode 36 to receive an output signal from the diode 36. According to this example, the computer 40 stores programs and subroutines for the system,
The reference EPT and other data are stored, the actual EPT is analyzed, and this EPT is compared with the reference EPT. In addition to storing the information of these EPT comparison results, a predetermined signal or control can be given to the plasma etcher or the operator of the apparatus to provide other desired functions.
The EPT comparison can be performed by programming the computer 40, and other functions described below can be performed, and a separate computer can be provided, and a part of the computer control system for the plasma etching reactor is installed. You can also.
In this case, such a computer control system needs to have the ability to sufficiently execute various functions described below. According to one embodiment of the present invention, the computer 40 comprises a Texas Instruments Explorer computer with software written in LISP. The software is designed to analyze any form of EPT and compare it to a reference EPT for the etching process.

FIG. 2 shows a simulation of a reference EPT for a particular etching process for one layer of oxidized material on a semiconductor slice in one embodiment of the present invention. In FIG. 2, the intensity is plotted as a function of time. This intensity corresponds to the intensity of the signal generated by the photodiode 36 in FIG. As mentioned earlier, this EP
The T apparatus is preset to monitor the carbon monoxide etching reaction product evaporated in the plasma.
The EPT in FIG. 2 shows a signal from the photodiode 36 from the time before the etching reaction started, although several stages were encountered during the plasma etching, to simulate the end of the plasma etching process. It is.
Thus, in FIG. 2, prior to T1 in region RO, the signal from photodiode 36 is below the threshold value 50, which indicates the lack of an excited species of plasma. This indicates that the plasma etching reaction has not yet started. Time T1
At the threshold level of 50
, The plasma etching reaction is started. The intensity of this EPT is changed from time T1 to T
A sharp increase to 2 can thus be indicative of the presence of the excited species plasma as well as a sharp increase in the concentration in the monitored species plasma. this
R1 corresponds to a particular phase of the etching operation, which is identical to each of the other regions R2-R5 of the EPT. For example, R2 represents the transition point from the starting phase R1 to the relatively stable phase R3, during which a predetermined amount of oxide material is etched from the surface of the slice, where The density (density) of the monitored species remains substantially constant. Region R4 represents a dip in the density of carbon monoxide species being monitored in the plasma and indicates that the oxide material or layer being etched in region R3 has been depleted. . The flat portion of the region R5 corresponds to an output signal from the plasma itself in a state where little or no carbon monoxide is contained in the plasma. In the flat region of R5, the intensity is relatively constant, indicating that little or no seed has been produced. The etching operation continues for a predetermined period of time after the end of the oxide etching as indicated by region R4, thereby removing the oxide material from the region of the etched slice. Can be completely washed. After a predetermined time, the etching operation is completed and the plasma is no longer generated. This is represented by a sharp drop in the intensity of the latter half of the region R5. In the region T6, the signal falls below the threshold value. The reason is that there is no excited species plasma.

The etching operation is designed to proceed through two or more layers of different materials. In such a case, the reference EPT will, of course, be different from the EPT shown in FIG. 2 and will include areas corresponding to the various layers and materials to be etched. EP like this
An example of T is shown in FIG. 7, which shows traces when etching through four different materials consisting of polysilicon, mitox, silicon nitride and silicon oxide. .

3 to 6 are configuration charts showing the functional architecture of a software program for controlling the computer 40, according to which one embodiment of the present invention is implemented.

FIG. 3 is an overall configuration diagram showing functions of one embodiment of the present invention designed to monitor a plasma etching operation. The embodiment shown in FIG. 3 is called "Plasma Etch Diagnostic Expert System" or "PEDX". Module 6 represents the PEDX system.

The system shown in FIG. 3 is represented by three general functional modules. The first general function module is shown at 62 and includes the functions that define a normal trace, ie, the EPT. A block diagram detailing various specific functions of the general module 62 is shown in FIG. 4 below. This PEDX system
The second general function of 60 is the signal-to-symbol conversion function represented by module 64. The various functions of module 64 are illustrated and fully described in connection with the following FIG. A third general function of the PEDX system 60 is to compare the actual endpoint trace with the reference endpoint trace, as shown in module 66. The function of this module 66 will also be described with reference to FIG. 6 below.

FIG. 4 is a block diagram for the function of the module 62 of FIG. Module 62 represents the general function for defining the reference trace in this example. As shown in FIG. 4, a general function for defining a reference trace includes a number of steps for defining an area in the trace. The function of defining the area is indicated by function block 70. The arrow 68 indicates the function block 70
Is performed several times, for example, for each region of the trace, and this function is analogous to a loop in a computer program chart. The function block 70 serves to define an object for describing each area of the reference EPT. The functions defining each area of the function block 70 include obtaining start and end points encompassing each time of the function block 72, obtaining or proving the material to be etched in the function block 74, Obtaining the shape of block 76, function block 78
And the function of finding the maximum and minimum points and printing information about the area for programming the function block 80.

The function of FIG. 4 for defining the area is executed for each area of the reference trace. The characteristics of FIG. 4 for each region are defined by the operator's knowledge of the importance of these regions and the characteristics of the region of the reference trace.

FIG. 5 is a block diagram of the operation of the system for executing the general functions related to the signal-to-symbol conversion shown in FIG. There are two primary steps in function block 64. The first step is to obtain the actual EPT as shown at 82. The second step is to match the actual EPT to the reference EPT, as indicated by function block 84. There are two primary components in the function block 84 that matches this actual EPT to the reference EPT. The first is represented by 86 and proves a point in the actual EPT, where there is a large slope change. These points are called critical points. Neighboring points between these critical points have the same slope, so they are grouped together. An area is defined as the portion of the trace between two consecutive critical points. The functions of the program for specifying these critical points are
Shown in functional blocks from 86. The program first sets up a starting point in the list file 88. Next, the process moves to the next point, and the inclination 90 is calculated. The program either adds a point to the list 92 or sets a new starting point in the list 94 in relation to the calculated slope relative to the slope of the starting point of the list.

As described above with reference to FIG. 4, the object is defined and each area in the EPT is described. The attributes of the object include the average slope, the maximum and minimum values of the area, the intensity of the critical point, the slope and time, and other intensities as desired. Once a set of objects is determined for the reference EPT, it will never change, but the set of objects representing the actual EPT can be corrected by the matching function. This is the second component of the signal-to-symbol converter and is designated in FIG. 5 as function block 84.
The actual EPT area is combined with the reference EPT area by the matching component. If these regions correspond to the same state of the process, they are paired. The matching operation is difficult. Why?
Because the critical point of EPT is fundamentally different,
This is because there is a problem between the etching and the etching.

As a whole, the matching function matches the actual EPT region from the left to the right with the reference EPT region. For each region of the reference EPT, consider the critical point in the mismatch of the actual EPT. Using the order of comparison,
Select the two critical points of the actual EPT that delimit the matching region. This system is practical as follows. That is, the attributes are compared for their importance, which is done until a critical point is found in the actual EPT that optimally matches the critical point of the reference EPT. In this system,
We believe that the slope at the critical point is the most important attribute. As a result, the matching component can merge several specified regions of the actual EPT and divide them into one or select regions without causing any actual changes.

Referring again to FIG. 5, as indicated by function block 96, the second component of function block 84, which matches the actual EPT to the reference EPT, includes the actual EPT region in the reference EPT region. Means for matching are included.
As indicated by arrow 98, a series of functions subordinate from function block 96 are repeated for each region of the EPT. The first step in this function is area 100
Is to find a starting point. In this step, an analysis is performed to establish whether the point under consideration is the first point in the EPT 102 or the last point in the final area of the EPT 104.

At 106, the end point of the area 106 is found by the program. The program employs a practical set of features in determining the end points of the region and aligning these points with the reference EPT region. The first function is to obtain a candidate area along with the matching ramp 108. If there are several candidates, this program further obtains the identification function 110 and employs additional functions. These additional functions include obtaining a candidate with the correct height 112, obtaining a candidate with the correct duration 114, and obtaining a candidate with the correct time 116. On the other hand, if there are no candidates at 106, the program obtains fewer identification functions 112 and selects a candidate with the correct time but with the wrong slope 120 and furthermore the correct height but incorrect Obtaining a candidate with a slope 122 is included.

The third function of function block 96 is a fine tuning of the result 124 (good tuning). In performing this tuning, the reference and actual
Collect both adjacent regions of EPT 126 and determine if these adjacent reference regions are pointing from above to below or from below to above. Second, this system is
Check the association between the region of T and the adjacent region, determine the state of the region with respect to the left side of the actual EPT 130 region, determine the state of this region with respect to the right side 132, and then at 134 Coordinate the change. This includes shifting the critical point of the real EPT region to the left 136, shifting this critical point to the right 136, or continuing in the region until a change in the direction of the slope 14 occurs. ing.

FIG. 6 illustrates the function indicated by function block 66 in FIG.
FIG. 4 is a configuration diagram showing a job of a program to be executed in comparison with EPT. As shown in FIG. 6, this function involves obtaining a reference area 142 for each area, collecting the actual area 144, and then executing a set of process-specific rules for the area 146. Is included. As described above, process-specific rules are executed to analyze each of the independent regions of the actual EPT in detail. In addition, the rules include different sets of comparisons, and further include the analysis of one region against the other. Initiating execution of the set of process-specific rules for region 146 includes initiating process-specific rules 148 and initiating process-independent rules 150.

With reference to FIGS. 7 and 8, an operation example of the system of the present invention in the matching area of the EPT is shown.
FIG. 7 shows an example of a reference endpoint trace and intensity plotted as a function of time. In FIG.
An example of the actual endpoint trace to be matched by the system is shown for the reference endpoint trace of FIG. In matching the region of the actual end point trace of FIG. 8 with the reference end point trace of FIG. 7, the program firstly sets the point A 'in FIG.
Assume that it matches point A in the figure. This corresponds to the functional module 100 in FIG. Next, the program selects a point corresponding to the point B of the reference end point trace in FIG. 7 from the actual end point trace (for example, see the function module 106 in FIG. 5). Critical points B ′ and D ′ can be confirmed as candidates for matching with critical point B. The reason is that all these points are at the end of the region with a slope comparable to the slope of point B described above. The next attribute of the system comparison is the intensity comparison of the critical points B ', D' to the intensity at point B. In this case, the critical point B 'is not close to the intensity of point B, but D' is close to B, after which D 'is selected and matched with B, and points A' and D '
Are fused to form a single region ending at point D '. In this example, the remaining area of the actual EPT is matched in a direct way.

Another example of the program's ability to match between regions is shown in FIG. Figure 9 shows the actual EP
This shows an example of T, where it is compared with the reference end point trace of FIG. For comparison under the present system, point A 'in FIG. 9 is matched with point A in FIG. Further, the point B 'is matched with the point B, and the points A' to B '(indicated by the area 2') are changed to the areas B to C in FIG.
(Displayed in area 2). However, region 2 'in FIG. 9 is of a much longer duration, which is longer than region 2 (corresponding) in FIG. According to the present system, the extended duration of the region 2 'of the EPT in FIG. 9 can be easily handled. This is because the system does not define a critical point from point B 'until there is a change in the slope of the predetermined magnitude. In FIG. 9, a change in tilt occurs at point C '. Thus, with this system, there is an extended duration, but the ninth
Region 2 'in the figure is matched against region 2 of short duration in FIG. In accordance with the present system, it is determined that point C 'is a suitable critical point at the end of region 2' by matching other data in the region, such as intensity, with those expected for this critical point and region. You can confirm by confirming that Further, the present system can confirm that the area adjacent to the area 2 'matches the corresponding expected area of the reference EPT in FIG. This illustrates the potential of the present invention, even if the area of the actual end point trace is considerably extended from the expected duration in reference to the reference end point trace. The area of the point trace can be matched to the area of the reference end point trace. Furthermore, this illustrates the potential of the present invention, allowing regions to "float" over time, as well as accurately matching and comparing. The regions dependent on point C '(eg, regions C'-D' and D'-E ') are:
They are "floating" and are usually much slower than can be expected from these points. Further, the present invention has a function of accurately confirming and comparing these regions.

Also, the system of the present invention allows matching of the regions of the actual end point trace, the duration of these regions being shorter than that of the corresponding region of the reference end point trace. .

The examples of FIGS. 8 and 9 illustrate the potential of the present system, using a set of practical functions to ensure that unexpected data patterns may occur during the actual end point trace. The area of the actual end point trace can be matched with the area of the reference end point trace. According to the invention, at the output of the signal-to-symbol converter,
For example, a problem associated with etching can be detected and diagnosed using the rules for operating the module 64 shown in FIG. This system is composed of two sets of rules, a process independent rule and a process specifying rule.

According to the process independent rule, the area of the actual trace is compared with the area of the reference trace, and an abnormality is searched for. By comparing the intensity, slope and time of the critical points in the reference and actual endpoint traces, these rules are applied to any plasma etching process. The conclusion of these process-independent rules is symbolic, for example, the result of a rule that compares the time of two critical points is
It can be described as "too early,""toolate," or "no problem." Further, according to the process independent rule, it is possible to search for an abnormality or irregularity in a region such as a positive or negative peak or a large number of peaks.

On the other hand, the cause of the problem can be confirmed by the process specification rule. When these specialization rules are grouped, knowledge about different areas can be represented by each group. Process-specific rules have been developed by process engineers, who have worked with specific processes and are familiar with various issues and corresponding end-point trace shapes. Rules are written by the process engineer to address the symptoms, identifying appropriate process-independent rules and addressing each problem by combining one or more causes. Further, a set of these rules is obtained by a process independent rule, and trace areas are compared or analyzed in some cases. Thus, these process-specific rules continue using what is found from the process-independent rules.

In analyzing the actual end point trace of FIG. 8, according to the system of the present invention, each area of FIG. 8 is compared with the area of FIG. In this comparison, these rules are:
Ignore cases where regions are almost identical and detect the presence of large differences between regions. According to the process-independent rule for comparing the times of the critical points in the region from points A 'to D' in FIG. 8, the end time of the final critical point D 'is determined by the point B in the reference curve in FIG. Can be shown to be too late when compared to the time. The conclusion of the process-specific rule, which called for a process-independent rule to check the time of the critical point, indicates that the last critical point of the region has occurred too late, and that this region will etch the polysilicon layer. Indicate what was intended to be indicated. The process-specific rules may suggest that the actual endpoint trace indicates during the etch that thin material was present on the polysilicon area to be etched.
Due to the thin material on this polysilicon, points A 'to D'
Abnormality will be induced during the EPT.

With these rules, an abnormality can be detected regardless of the size of the difference outside the allowable range. Tolerance depends on empirical knowledge of the process in the manufacturing environment. Given the failure extent, the process engineer can emphasize the values when writing these process specific rules. When a problem is detected, the system of the present invention can stop the plasma etcher and report a diagnosis result to a technician for corrective operation.

According to the present invention, it is possible to detect and diagnose the deterioration of the etching due to the error generated during the above-described process. One of the major causes of these errors is due to the deposition process. Here too much or too little material is deposited. One such example is illustrated in the actual EPT of FIG. Area 2 '
Has an unusually long duration, which corresponds to the reference EP in FIG.
It is longer than the region 2 of T. The process-specific rules applied to region 2 'indicate that this region is given an unusually long etch time and that the material to be etched in this region is polysilicon. Second, an unusually long duration suggests results that indicate that the particular polysilicon layer to be etched is deposited too thinly on the semiconductor device. Examples of other process steps that may be erroneously performed before monitoring the etching process include a photolithography step, an etching step, or other processes.

According to the present invention, the endpoint trace can be interpreted by combining the signal-to-symbol transformation as well as the rule criteria reasons. These signal-to-symbol conversion and process-independent rules are applicable to any plasma etching process or other process that provides a suitable continuously variable data curve. If a problem arises with the etching process, this problem can be detected by a small set of process independent rules. A set of process-specific rules diagnose this problem by combining the cause with one or more symptoms.

As is also evident, the system of this embodiment of the invention is modular, so that knowledge about the process to be monitored can be isolated at the process specific rule level. The other key components of the system, the signal-to-symbol converter and the set of process-independent rules, do not depend on the knowledge of the particular process (or etching process) to be monitored and any process that results in a suitable continuously variable data curve. (Or an etching process). Thus, embodiments of the present invention can be easily, effectively and quickly applied to specialized uses with any process that can provide a suitable data curve.

There is also a particular benefit when the present invention is used with a plasma etching reactor. Many of these benefits are due to the complexity of the operation of the plasma etch reactor. This complexity results from a number of factors that affect whether the etching operation proceeds at its best. The present invention, which directly observes the characteristics of the reaction itself rather than the operating parameters of the reaction vessel, is more effective than the conventional monitoring of the etching process, because there are many factors affecting the actual etching reaction. A highly reliable and direct means can be provided. In summary, according to embodiments of the present invention, unlike process control parameters, the process itself is monitored and monitored. Examples of process control parameters that can be changed in a plasma etch reactor include power, pressure, checking the relative concentration and content of gas supplied to the system, changing the total gas flow to the reactor, and changing its pressure and temperature. Is included. Some of these process control parameters are typically monitored by hardware control of the etch reactor.

However, a number of additional factors beyond these control processes affect the process inside the etch reactor. Some of these parameters include what is referred to as a chamber sheathing or character of the material on the inside surface of the reaction vessel. Recombination of surface materials on the inner surface of the chamber frequently occurs in the etch reactor, thereby affecting the progress of the etch reaction in the chamber. Another factor is the distance of the electrode from the slice surface. This electrode itself is also slightly etched during operation of the reactor. After multiple etchings, the distance between the slice surface and the electrode will increase due to the electrode etching process and, consequently, the affected etching reaction. These factors beyond the control parameters are not easily affected by the monitoring operation.

Small variations in one or more of the above factors can have a significant effect on whether the etching reaction can proceed in the best or acceptable way. However, due to the complexity in the correlation of species factors, it is difficult to predict the effects of variations in one or more factors on the actual etch reaction itself. Due to this complexity, according to the invention,
Special advantages are obtained. With traditional hardware,
Only a few of the factors that affect the response are controlled by the etcher monitor, and, as mentioned above, many of these factors do not easily affect this monitoring operation. Furthermore, the hardware controls only the monitor factor that affects the reaction, and does not control the reaction itself. Thus, in many cases, several factors will change and adversely affect the etch reaction, but if a hardware monitor indicates the exact set of existing process control parameters (eg, correct pressure, temperature, etc.). , Gas flow rate), the hardware monitor could not detect that the etching reaction had proceeded incorrectly. However, according to the present invention, by monitoring the process in an observable state (e.g., the rate of formation of reaction product species), the actual etching reaction can be more accurately monitored, and when an erroneous process occurs. , It is possible to perform more focused detection as compared with the conventional system.

Still further, according to the present invention, an actual continuously variable curve,
For example, it is possible to provide a system that can define and match the area of the actual EPT curve. According to this system, the above-described operation can be realized even when these regions are significantly deviated from the region of the continuously variable curve of the specific reference already defined. For example, the present invention can define the area of the actual curve that can float or extend over time. This provides a great benefit to a curve comparison system that compares between regions of a curve where the regions are invariably defined as a function of time. Furthermore, the practical approach of the present invention for matching critical points and regions allows the regions of these curves to be accurately defined, matched and compared.

According to one embodiment of the present invention, by inspecting and analyzing the end point (EPT) of a plasma etching process, there is an effect that a process-related problem occurring during a typical plasma etching process can be detected. Early and automatic detection of such problems can greatly increase the slice generation rate while preventing erroneous processing of the next slice to be processed. Furthermore, according to the present invention, since a predetermined cause is detected, a problem can be recognized, and a signal indicating these causes can be generated.

Furthermore, the invention can be used for real-time applications.
I.e., cooperating with other systems, such as, for example, expert systems, or actually working alone,
The etching process can be monitored in real time so that when an abnormality is detected, the etching parameters during the etching are changed or corrected.

Also, according to an additional benefit of the present invention, it is not necessary to install a strip chart recorder in a clean room, and a large number of end point traces can be edited by saving only end point traces exhibiting anomalous behavior. effective.

Further, the system of the present invention functions as a tool for process monitoring, which allows the microprocessor to interpolate based on hardware monitoring capabilities. Setting alarms through hardware monitors and disabling processing based on hardware issues (eg, no RF power, no gas, improper pressure or other similar issues) Thus, according to an embodiment of the present invention, the operator can be alerted, and finally the etcher can be stopped at a reaction related problem.

According to the present invention, it is possible to provide a system capable of observing an etching reaction and detecting an error during an etching operation that cannot be detected by monitoring the equipment, and the equipment simply has a hardware function,
That is, it only monitors the gas flow rate, temperature, or RF power setting of the etcher. Further, the system of the present invention having a backup monitoring system for a hardware monitoring device of the matching reactor can be provided. Therefore, the hardware monitor sensor fails,
According to the present invention, when the heart wear function becomes lower than the performance, this problem can be detected as soon as the etching reaction changes from the reference reaction due to the hardware function that has not performed well.

Further, the present invention can be effectively used in various situations. For example, it can be applied to various etching operations,
Each etching operation has its own reference EPT. Each of these various EPTs has a different number of regions, and these regions also have different shapes. Furthermore, it has the ability to define various properties of each area and to detect or measure such properties by taking into account the uniqueness of the area to be etched or a particular etch. Further, the present invention can be used for processes other than the plasma etching reaction.

In the embodiment shown in FIG. 1, an analog signal from the photodiode signal generator is received, but not only an analog signal but also a digital signal can be used.

As described in detail above, the present invention is not limited to only the above-described embodiments, and various modifications can be easily made by those skilled in the art without departing from the technical idea of the present invention. is there.

 In connection with the above description, the following items are disclosed.

1. establishing a reference endpoint trace for a predetermined etching process, dividing the reference endpoint trace into a predetermined region, introducing the predetermined etching process into a semiconductor device, Collecting actual endpoint traces for device etching, dividing the actual endpoint traces into candidate regions according to predetermined criteria, and matching the characteristics of the candidate regions of the actual endpoint traces. By analyzing over the properties of the end point trace area of the power reference, the area of the actual end point trace is matched to the corresponding area of the reference end point trace, Comparing the characteristics of the region of interest with the corresponding characteristics of the matched region of the endpoint trace of the reference. The plasma etch reactor of end point monitor trace, characterized in that it comprises a-up (monitoring)
how to.

2. The method further comprises the step of generating a signal representing a variable of a characteristic of the actual end point trace area exceeding a predetermined limit value from a corresponding characteristic of the reference end point trace matching area. A method according to claim 1 (hereinafter simply referred to as "claim 1").

3. The method of claim 2, wherein the predefined criteria for dividing the actual endpoint trace into candidate regions includes a change in the slope of a point along the actual endpoint trace.

4. comparing the characteristics of the area of the actual end point trace with the corresponding characteristics of the matched area of the reference end point trace comprises: setting a set of rules to at least one of the areas of the actual end point trace; A method according to claim 3, comprising the steps of:

5. The method of claim 4, wherein the set of rules includes a set of process independent rules and a set of process specific rules.

6. applying at least one prior expectation in the respective area between the area of the actual end point trace and the matched area of the reference end point trace in applying the set of process independent rules. Claim 5 characterized by the step of comparing at least one of the value, the slope and the time of the determined point.
The described method.

7. determining whether the deviation between the characteristic of the actual end-point trace and the corresponding characteristic of the reference end-point trace exceeds a predefined value; The method of claim 3 further comprising the step of generating a signal indicative of at least one predefined cause attributable to said defined cause, said attributable attribute of said deviation.

8. dividing said actual end point trace into candidate regions according to said predefined criteria, determining a slope of said trace at a point along said actual end point trace; Determining a critical point of an actual end point that exceeds a predetermined value of, and further dividing the actual end point trace into candidate regions between the determined critical points. The method of claim 2 wherein:

9. By analyzing the characteristics of the actual end point trace candidate area over the characteristics of the reference end point trace area to be matched, the actual end point trace candidate area corresponds to the reference end point. 3. The method of claim 2 wherein the step of matching to the region of step comprises applying a set of practical functions to the region of the actual endpoint trace.

10. in the practical function; ascertaining a real end trace area having an average slope that varies by less than a predetermined value from the average slope of the reference end trace area to be matched; Identify those trace end points where the intensity value at the end point of the actual end point trace changes by less than a predetermined intensity change from the intensity value at the end point of the end point trace area of the reference end point trace to be matched. Identifying an actual endpoint trace area having a duration that varies from the duration of the reference endpoint trace area by a value less than a predetermined duration change value; and a predetermined time. At least one of the operations of ascertaining the area of the actual endpoint trace occurring within the range.
A method as claimed in claim 9, comprising three actions.

11. In monitoring the operation of a process device performing a predetermined process, the process is first monitored by a detector to obtain a continuously variable signal curve corresponding to the progress of the process, and the reference is continuously variable. A method wherein a signal curve may be defined to correspond to a predetermined acceptable operation of a predetermined process, comprising: defining a reference continuously variable signal curve for a predetermined process; Defining characteristics for at least one region of the variable signal curve, introducing the predetermined process, collecting from the detector an actual continuously variable signal curve corresponding to the progress of the introduced process; The actual continuous variable signal curve obtained is divided into candidate regions based on the characteristics thereof, and the characteristics of the candidate region of the actual continuous variable signal curve are matched. Matching the candidate region of the actual continuously variable signal curve with the region of the reference continuously variable signal curve by analyzing over the entire characteristic of the region of the reference continuously variable signal to be trained; Comparing at least one characteristic of the region of the continuously variable signal curve with a characteristic of a matched region in the reference continuously variable signal curve, and further comparing the characteristic of the region of the actual continuously variable signal curve that exceeds a predefined limit; A method of monitoring, comprising generating a signal representing a variable in one characteristic from a corresponding characteristic of a matched region of the reference continuously variable signal curve.

12. The method according to claim 11, characterized in that, based on the fact that the actual continuously variable signal curve is divided into candidate regions, its characteristics do not essentially include the time component of this curve.

13. Claim 11 characterized by identifying critical points in the actual continuously variable signal curve, dividing the signal curve into candidate areas, and allowing these candidate areas to exist between the critical points. Method.

14. The claim characterized in that the critical point has been identified on the basis of a change in the slope of the continuously variable signal curve.
13. The method according to 13.

15. The claim 11 characterized in that the step of matching the candidate region of the actual continuously variable signal to the region of the reference continuously variable signal includes the step of applying a practical set of functions to the candidate region. the method of.

16. The practical function includes: the area of the actual continuously variable signal curve having an average slope that varies from the average slope of the area of the reference continuously variable signal curve to be matched by less than a predefined average slope value. That the intensity value at the end of this actual signal curve changes from the intensity value at the end of the region of the reference signal curve to be matched by a value less than a predetermined intensity variation. Identifying an area of the signal curve, identifying an area of the actual signal curve having a duration that varies by less than a predefined duration change value from the duration of the reference continuously variable signal curve; A method as claimed in claim 15, further comprising the step of ascertaining the area of the actual continuously variable signal curve occurring within a predetermined time range. .

17. The method according to claim 13, wherein the step of matching the candidate area of the actual continuously variable signal to the area of the reference continuously variable signal includes the step of applying a practical set of functions to the candidate area. Method.

18. The practical function includes: the area of the actual continuously variable signal curve having an average slope that has changed from the average slope of the area of the reference continuously variable signal curve to be matched by less than a predetermined average slope value. That the intensity value at the end of this actual signal curve changes from the intensity value at the end of the region of the reference signal curve to be matched by a value less than a predetermined intensity variation. Identifying an area of the signal curve, identifying an area of the actual signal curve having a duration that varies by less than a predefined duration change value from the duration of the reference continuously variable signal curve; A method as claimed in claim 17, further comprising the step of ascertaining the area of the actual continuously variable signal curve occurring within a predetermined time range. .

19. comparing the area of the actual variable signal curve to the area of the reference variable signal curve comprises applying a set of rules to at least one of the areas of the actual variable signal curve. A method according to claim 11, characterized in that:

20. The method of claim 19 wherein said set of rules comprises a set of process independent rules and a set of process specific rules.

21. The step of applying the set of process-independent rules includes, between the region of the actual signal curve and the matched region of the reference signal curve, the value of at least one predefined point in each of these regions. 21. The method of claim 20, comprising comparing at least one of: slope, time, and time.

22. determining whether the deviation between the characteristic of the actual signal curve and the corresponding characteristic of the reference signal curve exceeds a predefined value; At least one of the following: and generating a signal confirming the at least one predefined cause.

23. The step of dividing the actual signal curve into candidate regions includes determining a slope of the curve at a point along the actual signal curve, wherein the region varies beyond a first predefined value. Determining a critical point on the actual signal curve, and dividing the actual signal curve into candidate regions between the determined critical points.

24. The method of claim 11, wherein said predetermined process is provided with plasma etching.

25. The method according to claim 18, wherein said predetermined process is provided with plasma etching.

26. The method according to claim 21, wherein said predetermined process is provided with plasma etching.

27. The method of claim 8, wherein the duration of the candidate region is modified to improve the matching of the actual endpoint trace candidate to the reference endpoint trace region.

28. To monitor the end point trace of the plasma etch reactor, establish a reference end point trace for a predetermined etching process, identify critical points in this reference end point trace, Identifying the region of the reference endpoint trace between the critical points, introducing the predetermined etching process into the semiconductor device, collecting the actual endpoint trace for the etching of the semiconductor device, Critical point candidates are identified in this trace based on the change in slope of the end point trace, and the actual end point trace is divided into candidate regions between the critical point candidates, and the actual end point trace Matching a candidate area to an area of the reference end point trace; Comparing at least one characteristic with a corresponding characteristic of a corresponding region of the reference endpoint trace, and further wherein at least one characteristic of at least one region of the actual endpoint trace is an endpoint of the reference; Generating an indication from a corresponding characteristic of a corresponding area of the trace that exceeds a predetermined limit value.

29. The step of matching the candidate region of the actual end point trace with the region of the reference trace includes a step of comparing the characteristic of the candidate region of the actual trace with the characteristic of the region of the reference trace. 30. The method of claim 28, wherein:

30. Matching the candidate area of the actual trace to a corresponding area of the reference trace further provides a practical set of functions for comparing the properties of the candidate area with the properties of the endpoint trace of the reference. The method according to claim 29, comprising a step.

31. The set of practical functions includes: a slope at the end of the candidate area; an average slope of the area; an intensity at an end point of the area; a duration of the area; A method comprising comparing at least one of the properties consisting of time of a region.

32. Matching the candidate region of the actual end point trace to the region of the reference end point trace includes: determining a characteristic of at least one region adjacent to the candidate region of the actual trace; 32. The method of claim 31 including the step of comparing to a characteristic of a corresponding region adjacent to the region of the end point trace.

33. Adjust the limit value of the candidate area to be matched beyond the critical point candidate identified on the basis of the change in slope, thereby adjusting the actual trace candidate area to the reference trace area. 32. The method of claim 32, wherein the method is more accurately matched to

34. A data storage for receiving reference data representing a reference continuously variable signal corresponding to a predefined process, and an actual representing a continuous variable signal curve corresponding to the actual operation of said predefined process. And a processor for dividing the actual data into candidate regions based on the characteristics of the actual data; and a processor for dividing the characteristics of the candidate regions into at least one of the reference data.
A matcher that matches at least one candidate region of the actual data to a region of reference data by analyzing over the characteristics of the two regions; and
A comparator for comparing the actual data area with the characteristic of the matched reference data area; and a signal representing a variable of the actual data area characteristic that exceeds a predetermined limit value. And a generator for generating the data based on the corresponding characteristics of the reference data area matched with the data area.

35. The apparatus of claim 34, wherein the processor is operative to divide the actual data into candidate regions based on a change in a slope of the actual data.

36. Apparatus according to claim 35, wherein the matching device applies a practical set of functions to the candidate area and matches it to the reference data area.

37. The apparatus according to claim 36, wherein said predetermined process includes a plasma etching operation.

38. The apparatus of claim 37, wherein the actual continuously variable signal curve includes an end point trace signal from a plasma etcher.

39. In monitoring the end point trace of the plasma etch reactor, establish a reference end point trace for a predetermined etching process, divide the reference end point trace into a predetermined area, Introducing the predetermined etching process into a semiconductor device, collecting an actual end point trace for the etching of the semiconductor device, and dividing the actual end point trace into candidate regions according to a predetermined standard. Further, by analyzing the characteristics of the candidate region of the actual end-point trace over the entire characteristics of the region of the reference end-point trace to be matched, the candidate region of the actual end-point trace can be obtained. An end point trace, comprising matching to a corresponding area of the reference end point trace How to monitor.

40. A data store receiving reference data representing a reference continuously variable signal curve corresponding to the plasma etching process, and collecting actual data representing an actual continuously variable signal curve corresponding to the actual operation of the plasma etching process. A processor for dividing the actual data into candidate regions based on the characteristics of the actual data; and analyzing the characteristics of the candidate regions over the entire characteristics of at least one region of the reference data. By
A matching device for matching at least one candidate area of the actual data with the area of the reference data.

41. Improved equipment and processes are provided for detecting abnormalities during operation of the manufacturing process. According to one embodiment, the operation of the plasma etching reactor is monitored to detect abnormalities during the etching operation. A reference endpoint trace (EPT) is defined for this etching process by the plasma etch diagnostic expert system (60). The regions are defined within the end point traces and characteristics of this criterion, and the tolerance for each region is defined. The etcher works and from this action the actual EP
T is obtained. The actual EPT is analyzed to identify the region of the EPT, and then the region of the EPT is matched to the region of the reference EPT. According to this system, this real EP
In matching the T area to the reference EPT area,
Use a set of practical functions. The properties of the matched area of the actual endpoint trace are compared to the properties of the corresponding area of the reference endpoint trace to determine if an anomaly has occurred during the etching process. According to the present invention, the actual end point trace can be compared with the reference end point trace and can be matched well.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a typical plasma etching reactor having an end point trace monitor apparatus and computer means according to one embodiment of the present invention, and FIG. 2 is a reference end point according to one embodiment of the present invention. FIG. 3 is a chart showing the overall configuration of the software, FIG. 3 is a chart showing the general function of defining the reference trace according to the embodiment of FIG. 3, FIG. 5 is also a chart showing the general function of the signal-to-symbol converter, FIG. 6 is a chart showing the same function for comparing the end point traces, and FIG. FIG. 8 is a graph showing an example of a reference endpoint trace having intensity plotted as a function, FIG. 9 is a graph showing an example of an actual end point trace, and FIG. 9 is a graph showing an example of a second actual end point trace to be matched with respect to the reference end point trace of FIG. 10 Plasma etching reaction vessel 12 Electrode 20 Semiconductor slice 30 Plasma 32 Window 34 Optical filter 36 Photodiode 38 EPT trace recorder 40 Computer

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Bruce e Finchborough United States of America 75248 Dallas Copper Creek Drive 6518 (72) Inventor Salma es Grinturi United States of America Texas 75081 Richardson Stoneborough 1403 (72) Inventor Thomas W. Rashiter United States of America 75042 Texas Garland Heather Hill 3446 (72) Inventor Robert El Love United States Texas 75069-9579 McKinney Kentucky Lane 390

Claims (1)

(57) [Claims] Establishing a reference endpoint trace for a predetermined etching process, dividing the reference endpoint trace into a predefined region, and performing the predetermined etching process on a semiconductor device. Obtaining an actual endpoint trace for the etching of the semiconductor device, dividing the actual endpoint trace into candidate regions according to a predetermined criterion, taking into account the characteristics of the region of the reference endpoint trace to be matched. Analyzing the characteristics of the candidate area of the actual end point trace to match the candidate area of the actual end point trace with the corresponding area of the reference end point trace; Comparing the characteristic with the corresponding characteristic of the matched region of the endpoint trace of the reference. Method for monitoring the end point trace of the plasma etching reactor, characterized by Bei.