CN115077446A - Method for adjusting step instrument - Google Patents
Method for adjusting step instrument Download PDFInfo
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- CN115077446A CN115077446A CN202210513113.6A CN202210513113A CN115077446A CN 115077446 A CN115077446 A CN 115077446A CN 202210513113 A CN202210513113 A CN 202210513113A CN 115077446 A CN115077446 A CN 115077446A
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- step height
- correction factor
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- sample plate
- instrument
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B21/00—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant
- G01B21/02—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant for measuring length, width, or thickness
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B21/00—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant
- G01B21/02—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant for measuring length, width, or thickness
- G01B21/08—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant for measuring length, width, or thickness for measuring thickness
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- A Measuring Device Byusing Mechanical Method (AREA)
Abstract
The invention provides a method for adjusting a step instrument, which comprises the following steps: selecting step height templates with different preset heights; testing all the step height sample plates by using a step instrument to be calibrated, and obtaining a correction factor of each step height sample plate; determining a final correction factor of the step instrument to be calibrated based on the correction factor of each step height sample plate; and inputting the final correction factor into the measurement software of the step instrument to be calibrated, namely calibrating the step instrument to be calibrated. The step height templates with different heights are tested by the step instrument to be calibrated to obtain a plurality of correction factors, and then the final correction factor is obtained through the plurality of correction factors, so that the reliability of the correction factor is ensured.
Description
Technical Field
The invention relates to the technical field of measurement, in particular to a method for adjusting a step profiler.
Background
The step gauge has the characteristics of high measurement precision, wide range, stable and reliable measurement result, good repeatability and the like, and is widely applied to the semiconductor industry for monitoring the height of the step structure in the process of processing.
However, as the step meter is used for a long time, the accuracy of measuring the height of the step is reduced, which affects the accuracy of monitoring the process. Therefore, the step profiler needs to be periodically calibrated to ensure its measurement accuracy.
With the development of the field of nanotechnology and micromachining, the requirement on the test precision in the vertical direction within the range from nanometer to micrometer is higher and higher. At present, a common step instrument has a step height adjusting function, but the adjusting accuracy is low, and the accuracy requirement of the current semiconductor industry on the adjustment of the step instrument cannot be met. Therefore, a method for adjusting the height of the step-height gauge with high precision is needed.
Disclosure of Invention
The embodiment of the invention provides a method for adjusting a step profiler, which aims to solve the problem of low accuracy of the conventional step profiler adjustment.
In a first aspect, an embodiment of the present invention provides a method for adjusting a step profiler, including:
selecting step height templates with different preset heights;
testing all the step height sample plates by using a step instrument to be calibrated, and obtaining a correction factor of each step height sample plate;
determining a final correction factor of the step instrument to be calibrated based on the correction factor of each step height sample plate;
the final correction factor is input into the measurement software of the step meter to be calibrated.
In one possible implementation, the step meter to be calibrated is used to test all step height templates and obtain a correction factor for each step height template, including:
testing all the step height sample plates by using a step instrument to be calibrated to obtain a measured value of each step height sample plate;
and determining the correction factor of each step height sample plate based on the measured value of each step height sample plate, the standard value of each step height sample plate and the original correction factor of the step instrument to be calibrated during calibration.
In one possible implementation manner, determining the correction factor of each step height sample plate based on the measured value of each step height sample plate, the standard value of each step height sample plate, and the original correction factor of the step appearance to be calibrated during calibration includes:
determining the ratio of the standard value of each step height sample plate to the measured value of each step height sample plate as a transition correction factor of each step height sample plate;
and determining the product of the transition correction factor of each step height sample plate and the original correction factor of the step instrument to be calibrated during calibration as the correction factor of each step height sample plate.
In one possible implementation, the step height templates are all tested using the step meter to be calibrated, and the measured value of each step height template is obtained, including:
and respectively testing each step height sample plate for multiple times by using the step instrument to be calibrated, and determining the average value of the multiple tests of each step height sample plate as the measured value of each step height sample plate.
In one possible implementation, determining a final correction factor for the step apparatus to be calibrated based on the correction factor for each step height template includes:
and multiplying the correction factor of each step height sample plate by a preset multiple respectively to determine the sum as the final correction factor of the step instrument to be calibrated.
In one possible implementation manner, the sum of the correction factors of each step height sample plate multiplied by the preset multiple is determined as the final correction factor of the step instrument to be calibrated, and the method includes the following steps:
and determining the average value of the correction factors of all the step height templates as the final correction factor of the step instrument to be calibrated.
In one possible implementation, selecting a plurality of step height templates with different preset heights includes:
and determining step height sample plates with different preset heights based on the upper range limit of the step instrument to be calibrated.
In one possible implementation, a step height template with a preset height corresponding to the height of each measurement range is arranged in each measurement range of the step meter to be calibrated.
In one possible implementation, the step height templates with different preset heights comprise:
the preset heights are three step height templates which are respectively 10%, 50% and 90% of the upper limit of the measuring range of the step meter to be calibrated.
In one possible implementation, the step gauge to be calibrated is a pressure contact step gauge or a contact atomic force microscope.
The embodiment of the invention provides a method for adjusting a step instrument. Then, all the step height templates are tested by using the step meter to be calibrated, and the correction factor of each step height template is obtained. Then, based on the correction factor for each step height template, a final correction factor for the step meter to be calibrated is determined. And finally, inputting the final correction factor into the measurement software of the step profiler to be calibrated, namely calibrating the step profiler to be calibrated. The step height templates with different heights are tested by the step instrument to be calibrated to obtain a plurality of correction factors, and then the final correction factor is obtained through the plurality of correction factors, so that the reliability of the correction factor is ensured.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.
FIG. 1 is a schematic diagram of an existing step gauge with improper adjustment and selection points;
fig. 2 is a flowchart of an implementation of a method for adjusting a step profiler according to an embodiment of the present invention.
Detailed Description
In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.
In order to make the objects, technical solutions and advantages of the present invention more apparent, the following description is made by way of specific embodiments with reference to the accompanying drawings.
As described in the background, a step meter uses a stylus to contact the surface of an object, and an inductive or capacitive sensor connected to the stylus to measure the magnitude of the undulations on the surface of the object. The method has the characteristics of convenience in operation, high measurement speed, high sensitivity, good repeatability, strong adaptability, visual test result and the like, and is widely applied to measurement of the sizes of a mask plate, an epitaxial layer, a passivation layer, photoresist, an oxide layer and the like, and the conventional process parameters of step characteristics, local flatness and the like. With the development of the field of nanotechnology and micromachining, the requirement on the measurement precision in the vertical direction within the range from nanometer to micrometer is higher and higher, so how to adjust the step instrument is more and more important, and the measurement accuracy of the adjusted step instrument is improved.
After the step appearance is used for a long time, its measuring accuracy can decline to some extent, influences the accuracy of monitoring. It must be periodically calibrated in order to ensure the accuracy of its measurement. The P-6 type step meter manufactured by KLA corporation of usa is taken as an example, and the meter has three measuring ranges of high, middle and low, and each measuring range can be independently adjusted and calibrated. The current tuning process is: first, a range to be adjusted is selected, and a step height template having a random band height of 1 μm is selected. Then, the module is measured by using a step profiler, and the step profiler can automatically obtain a correction factor of the selected measuring range according to the measurement result and give the correction factor to software.
However, the inventors have found in long-term work that the above tuning method has two drawbacks: first, the correction factor depends on the accuracy of the step height template, and if the step height template is inaccurate in magnitude, the correction factor will also be biased. Secondly, the measurement range of each measuring range is large, the whole measuring range is not necessarily linear, the calibration process only uses one step height sample plate to determine a correction factor comparison surface, such as H in the schematic diagram of the step meter in the improper calibration in FIG. 1 1 Or H 2 The correction result is inaccurate due to different points and selected points.
In order to solve the problem of the prior art, the embodiment of the invention provides a method for adjusting a step profiler. First, a method for adjusting a step profiler provided by an embodiment of the present invention is described below.
A method for adjusting a step instrument comprises the following steps:
s110, selecting step height templates with different preset heights.
Because the step meter comprises a plurality of measuring ranges, step height templates with different heights are respectively selected for each measuring range to be tested, and the height values of the step height templates with all heights need to cover the measuring range of the step meter to be calibrated.
The step height templates with different preset heights are determined according to the upper range limit of the step instrument to be calibrated. Namely, a step height template with a preset height corresponding to the height of each measuring range is arranged in each measuring range of the step meter to be calibrated.
Specifically, the preset heights of the step height templates may be set to three step height templates of 10%, 50%, and 90% of the upper limit of the range of the step meter to be calibrated, respectively. Of course, the preset height may also be changed according to the adjustment requirement of the user, and is not limited herein.
And S120, testing all the step height sample plates by using the step meter to be calibrated, and obtaining the correction factor of each step height sample plate.
And S1210, testing all the step height templates by using the step meter to be calibrated to obtain the measured value of each step height template.
For the accuracy of the test, the step meter to be calibrated is used for respectively carrying out a plurality of tests on each step height sample plate, and the average value of the plurality of tests of each step height sample plate is determined as the measured value of each step height sample plate. The specific times are that the user can select according to actual needs, and the method is not limited here.
And S1220, determining a correction factor of each step height sample plate based on the measured value of each step height sample plate, the standard value of each step height sample plate and the original correction factor of the step instrument to be calibrated during calibration.
In some embodiments, the ratio of the standard value of each step height gauge to the measured value of each step height gauge may be determined as the transition correction factor of each step height gauge. And then, determining the product of the transition correction factor of each step height sample plate and the original correction factor of the step instrument to be calibrated during calibration as the correction factor of each step height sample plate.
Specifically, the standard value of each step height template is the result obtained by calibrating the metering mechanism.
The following illustrates a method for calculating the correction factor for each step height template, and three step height templates are taken as examples.
The measured values of the three step height templates are respectively H 1 、H 2 And H 3 The standard value of the three step height templates is H 10 、H 20 And H 30 The original correction factor of the step meter to be calibrated during calibration is k 0 The correction factors of the three step height templates are respectively k 1 、k 2 And k 3 。
Then, the correction factor of the first step height template
Wherein H 1 ' measuring the uncorrected initial results of the first step height profile for the step profiler.
Similarly, the correction factor k of the second and third step height templates can be obtained 2 And k 3 。
Thus, the correction factors of the three step height templates are obtained as follows:
wherein, the step gauge to be calibrated is a pressure contact type step gauge or a contact type atomic force microscope.
And S130, determining a final correction factor of the step instrument to be calibrated based on the correction factor of each step height sample plate.
In some embodiments, the sum of the correction factors of each step height template multiplied by a preset multiple is determined as the final correction factor of the step meter to be calibrated. It should be noted that the preset multiple of each step height template herein may be the same or different.
In particular, the average of the correction factors of all step height templates may be determined as the final correction factor for the step apparatus to be calibrated.
I.e. the final correction factor
And S140, inputting the final correction factor into the measurement software of the step meter to be calibrated.
After the final correction factor is determined, the obtained final correction factor k can be input into the measurement software of the step instrument to be calibrated, so that the step instrument can be calibrated.
The adjusting method provided by the invention comprises the steps of firstly selecting step height templates with different preset heights. Then, all the step height templates are tested by using the step meter to be calibrated, and the correction factor of each step height template is obtained. Then, based on the correction factor for each step height template, a final correction factor for the step meter to be calibrated is determined. And finally, inputting the final correction factor into the measurement software of the step instrument to be calibrated, namely, calibrating the step instrument to be calibrated. The step height templates with different heights are tested by adopting the step instrument to be calibrated to obtain a plurality of correction factors, and then the final correction factor is obtained through the plurality of correction factors, so that the reliability of the correction factor is ensured.
It should be understood that, the sequence numbers of the steps in the foregoing embodiments do not imply an execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.
Hereinafter, the low measurement range of a P-6 type step meter manufactured by KLA will be described as an example, in which the upper limit of the measurement of the step meter is 13 μm.
Firstly, the heights of the selected step height sample plates are determined according to the upper limit of the measuring range of the step profiler, and are respectively the sample plates with the heights of 1 μm, 5 μm and 10 μm.
Then, three kinds of step height samples were measured respectively using a step meter, each sample was measured 6 times, and the average value of 6 times was taken as the measured value of each sample. The measured values of the three step height templates are respectively:
the standard value of the three step height templates is H 10 、H 20 And H 30 The original correction factor of the step meter to be calibrated during calibration is k 0 Then, the correction factors of the three step height templates are respectively:
and finally, obtaining a final correction factor based on the correction factors of the three step height templates:
and inputting the obtained final correction factor k into the measurement software of the step instrument to be calibrated.
The step height templates with three different heights are tested by adopting the step instrument to be calibrated to obtain correction factors corresponding to the step height templates with the three heights, and then the final correction factor is obtained by processing the three correction factors, so that the reliability of the correction factor is ensured.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the embodiments of the present invention, and they should be construed as being included therein.
Claims (10)
1. A method for adjusting a step instrument is characterized by comprising the following steps:
selecting step height templates with different preset heights;
testing all the step height sample plates by using a step instrument to be calibrated, and obtaining a correction factor of each step height sample plate;
determining a final correction factor of the step instrument to be calibrated based on the correction factor of each step height sample plate;
and inputting the final correction factor into the measurement software of the step meter to be calibrated.
2. The tuning method of claim 1, wherein the step height templates are all tested using the step meter to be calibrated and the correction factor for each step height template is obtained, comprising:
testing all the step height sample plates by using a step instrument to be calibrated to obtain a measured value of each step height sample plate;
and determining the correction factor of each step height sample plate based on the measured value of each step height sample plate, the standard value of each step height sample plate and the original correction factor of the step instrument to be calibrated during calibration.
3. The calibration method as claimed in claim 2, wherein the determining the correction factor for each step height template based on the measured value of each step height template, the standard value of each step height template, and the original correction factor of the step apparatus to be calibrated at the time of calibration comprises:
determining the ratio of the standard value of each step height sample plate to the measured value of each step height sample plate as a transition correction factor of each step height sample plate;
and determining the product of the transition correction factor of each step height sample plate and the original correction factor of the step instrument to be calibrated during calibration as the correction factor of each step height sample plate.
4. The tuning method of claim 2, wherein the step height templates are all tested using the step meter to be calibrated to obtain a measurement value for each step height template, comprising:
and respectively testing each step height sample plate for multiple times by using the step instrument to be calibrated, and determining the average value of the multiple tests of each step height sample plate as the measured value of each step height sample plate.
5. The tuning method of any one of claims 1-4, wherein determining a final correction factor for the step profiler to be calibrated based on the correction factor for each step height template comprises:
and multiplying the correction factor of each step height sample plate by a preset multiple respectively to determine the sum as the final correction factor of the step instrument to be calibrated.
6. The calibration method as claimed in claim 5, wherein the step of multiplying the correction factor of each step height template by a predetermined multiple and determining the sum as the final correction factor of the step meter to be calibrated comprises:
and determining the average value of the correction factors of all the step height templates as the final correction factor of the step meter to be calibrated.
7. The tuning method of claim 1, wherein the selecting step height templates with different preset heights comprises:
and determining step height sample plates with different preset heights based on the upper range limit of the step instrument to be calibrated.
8. The tuning method of claim 7, wherein each measuring range of the step profiler to be calibrated has a step height template with a predetermined height corresponding to the measuring range.
9. The tuning method of claim 8, wherein the step height templates with different preset heights comprise:
the preset heights are three step height sample plates respectively being 10%, 50% and 90% of the upper limit of the measuring range of the step meter to be calibrated.
10. The tuning method according to claim 1, wherein the step gauge to be calibrated is a pressure contact step gauge or a contact atomic force microscope.
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| CN202210513113.6A CN115077446A (en) | 2022-05-11 | 2022-05-11 | Method for adjusting step instrument |
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| CN202210513113.6A CN115077446A (en) | 2022-05-11 | 2022-05-11 | Method for adjusting step instrument |
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