Wafer three-dimensional surface topography measurement method

Abstract

The invention relates to a wafer three-dimensional surface topography measurement method. The method comprises the following steps: S1, setting a measurement system; s2, acquiring height data Z1 and Z2; s3, fitting ideal height data Z3; s4, calculating the fluctuation error of the loading disc: comparing the actually measured height data Z2 of the loading table with the ideal height data Z3 to obtain the fluctuation error of the loading disc at different positions, and the fluctuation error delta Z is equal to Z2-Z3; s5, carrying out linear change processing; s6, converting a data coordinate system; s7, obtaining final three-dimensional shape information; according to the invention, a non-contact measurement mode is adopted, and the runout error of the wafer can be accurately calculated, so that the adverse effect of the runout error on the three-dimensional shape data of the wafer is eliminated, and the measurement precision is improved.

Description

Technical Field

[0001] The present invention relates to the field of optical measurement technology, and in particular to a method for measuring the three-dimensional surface morphology of a wafer. Background Art

[0002] Three-dimensional topography information is becoming an increasingly important means of surface quality assessment because it can more comprehensively and realistically reflect the surface characteristics and processing quality of parts. By measuring the three-dimensional topography of part surfaces, the quality of the surface can be comprehensively evaluated, thus providing a basis for evaluating the effectiveness of processing methods and the rationality of design requirements. This process helps to optimize processing technology and improve production processes to ensure that the surface of the parts meets high-quality standards and realizes their intended use functions.

[0003] Currently, wafer topography measurement is mainly divided into contact measurement and non-contact measurement. In contact measurement, the probe of the instrument is passed across the surface of the part, and the data signal of the topography can be transmitted to the terminal device. When encountering an undulating surface, an undulating signal output result can be obtained. However, this type of equipment has the problem of damage to the part due to the probe head contacting the part and damage to the probe head itself, and it will affect the measurement accuracy in the process of unknowingly; non-contact measurement uses optical technology to measure the data of the three-dimensional topography of the part. Since the measuring probe does not contact the part, the problem of damage to the part and the probe head in contact measurement is solved. However, the wafer will have a jump error in the direction perpendicular to the table during rotation, which will also affect the measurement accuracy and urgently needs to be solved. Summary of the Invention

[0004] In view of the current status of the above-mentioned existing technologies, the technical problem to be solved by the present invention is to provide a wafer three-dimensional surface morphology measurement method that adopts a non-contact measurement method and can accurately calculate the wafer runout error, thereby eliminating the adverse effects of the runout error on the wafer three-dimensional morphology data, thereby improving the measurement accuracy.

[0005] The technical solution adopted by the present invention to solve the above technical problems is: a method for measuring the three-dimensional surface morphology of a wafer, characterized by comprising the following steps:

[0006] S1. Set up the measurement system;

[0007] S2, obtain altitude data;

[0008] S3, fitting ideal height data;

[0009] S4, calculating the loading plate fluctuation error ΔZ;

[0010] S5, linear change processing:

[0011] The fluctuation error ΔZ of the loading plate shows a linear change at different distances from the center point. The least squares method is used to fit a smooth straight line. The fluctuation value in the Z direction can be obtained by calculating the difference between the actual height and the ideal height in the Z direction, thereby reducing the data error.

[0012] S6. Data coordinate system conversion:

[0013] Based on the height data of the upper surface of the measured object obtained from the first measuring probe, the X and Y coordinates are calculated using the angle and distance from the detection point to the origin. At the same time, the Z coordinate is represented by ΔZ after linear transformation. Then, the cylindrical coordinate system is converted to a spatial rectangular coordinate system. The processed data can more intuitively display the three-dimensional morphology of the measured object.

[0014] S7. Obtain final three-dimensional shape information:

[0015] The three-dimensional topography information of the surface of the object being measured is obtained through the data in the spatial rectangular coordinate system, completing the entire process of measurement and data processing;

[0016] Preferably, the step S1 includes:

[0017] S11, disposing a first measuring probe above the object to be measured along the radial direction of the wafer, for measuring the relative height between the first measuring probe and the upper surface of the object to be measured;

[0018] S12. Dispose a second measuring probe above the stage along the radial direction of the wafer to measure the height between the second measuring probe and the stage.

[0019] Preferably, step S2 includes:

[0020] S21, obtaining Z1 data: recording the upper surface height data of the measured object at different rotation radii and different rotation angle positions by the first measuring probe;

[0021] S22, obtaining Z2 data: using the second measuring probe to record the height data of the stage during the same rotation process of the measured object.

[0022] Preferably, step S3 includes:

[0023] S31. Obtain ideal height data Z3:

[0024] According to the stage height data Z2 recorded by the second measuring probe, an ideal height curve is fitted to obtain the ideal height data at the corresponding position;

[0025] S32. Define the fluctuation error ΔZ:

[0026] The difference between the actual measured stage height data Z2 and the ideal height data Z3 is calculated to represent the fluctuation error of the stage.

[0027] Preferably, the step S4 compares the actually measured loading platform height data Z2 with the ideal height data Z3 to obtain the fluctuation error of the loading plate at different positions, where the fluctuation error ΔZ=Z2-Z3.

[0028] Compared with the prior art, the advantages of the present invention are:

[0029] The present invention adopts a non-contact measurement method and can accurately calculate the runout error of the wafer, thereby eliminating the adverse effects of the runout error on the three-dimensional shape data of the wafer, thereby improving the measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the measurement steps of the present invention;

[0031] Figure 2 Schematic diagram of the layout of the first measuring probe and the second measuring probe of the present invention. DETAILED DESCRIPTION

[0032] Unless otherwise defined, the technical or scientific terms used in the present invention shall have the usual meanings understood by persons of ordinary skill in the field to which the present invention belongs. The words "first", "second" and similar terms used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0033] In order to keep the following description of the embodiments of the present invention clear and concise, detailed descriptions of known functions and known components are omitted.

[0034] like Figures 1-2 As shown, a method for measuring the three-dimensional surface morphology of a wafer includes the following steps:

[0035] S1. Set up the measurement system:

[0036] S11, disposing a first measuring probe above the object to be measured along the radial direction (R axis) of the wafer, for measuring the relative height between the first measuring probe and the upper surface of the object to be measured;

[0037] S12, disposing a second measuring probe above the stage along the radial direction (R axis) of the wafer to measure the height between the second measuring probe and the stage;

[0038] S2. Get altitude data:

[0039] S21, obtaining Z1 data: recording the upper surface height data of the measured object at different rotation radii and different rotation angle positions by the first measuring probe;

[0040] S22, obtaining Z2 data: recording the height data of the stage during the same rotation process of the measured object by the second measuring probe;

[0041] S3. Fitting ideal height data:

[0042] S31. Obtain ideal height data Z3:

[0043] According to the stage height data (Z2) recorded by the second measuring probe, an ideal height curve is fitted to obtain the ideal height data at the corresponding position;

[0044] S32. Define the fluctuation error ΔZ:

[0045] Calculate the difference between the actual measured stage height data Z2 and the ideal height data Z3 to represent the fluctuation error of the stage;

[0046] S4. Calculate the plate fluctuation error:

[0047] ΔZ (fluctuation error): By comparing the actual measured stage height data Z2 with the ideal height data Z3, the fluctuation error of the stage at different positions is obtained. Fluctuation error ΔZ = Z2 - Z3;

[0048] S5, linear change processing:

[0049] The fluctuation error ΔZ of the loading plate shows a linear change at different distances from the center point. The least squares method is used to fit a smooth straight line. The fluctuation value in the Z direction can be obtained by calculating the difference between the actual height and the ideal height in the Z direction, thereby reducing the data error.

[0050] S6. Data coordinate system conversion:

[0051] Based on the height data (Z1) of the upper surface of the object being measured obtained from the first measuring probe, the X and Y coordinates are calculated using the angle and distance (R) from the detection point to the origin, and the Z coordinate is represented by ΔZ after linear transformation. The cylindrical coordinate system is then converted to a spatial rectangular coordinate system. The processed data can more intuitively display the three-dimensional appearance of the object being measured;

[0052] S7. Obtain final three-dimensional shape information:

[0053] The three-dimensional topography information of the surface of the object being measured is obtained through the data in the spatial rectangular coordinate system, completing the entire process of measurement and data processing.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for measuring the three-dimensional surface morphology of a wafer, characterized in that: The following steps are involved: S1. Set up the measurement system; S2, obtain altitude data; S3, fitting ideal height data; S4, calculating the loading plate fluctuation error ΔZ; S5, linear change processing: The fluctuation error ΔZ of the loading plate shows a linear change at different distances from the center point. The least squares method is used to fit a smooth straight line. The fluctuation value in the Z direction can be obtained by calculating the difference between the actual height and the ideal height in the Z direction, thereby reducing the data error. S6. Data coordinate system conversion: Based on the height data of the upper surface of the measured object obtained from the first measuring probe, the X and Y coordinates are calculated using the angle and distance from the detection point to the origin. At the same time, the Z coordinate is represented by ΔZ after linear transformation. Then, the cylindrical coordinate system is converted to a spatial rectangular coordinate system. The processed data can more intuitively display the three-dimensional morphology of the measured object. S7. Obtain final three-dimensional shape information: The three-dimensional topography information of the surface of the object being measured is obtained through the data in the spatial rectangular coordinate system, completing the entire process of measurement and data processing.

2. The method for measuring the three-dimensional surface topography of a wafer according to claim 1, wherein: The step S1 comprises: S11, disposing a first measuring probe above the object to be measured along the radial direction of the wafer, for measuring the relative height between the first measuring probe and the upper surface of the object to be measured; S12. Dispose a second measuring probe above the stage along the radial direction of the wafer to measure the height between the second measuring probe and the stage.

3. The method for measuring the three-dimensional surface morphology of a wafer according to claim 1, wherein: The step S2 comprises: S21, obtaining Z1 data: recording the upper surface height data of the measured object at different rotation radii and different rotation angle positions by the first measuring probe; S22, obtaining Z2 data: using the second measuring probe to record the height data of the stage during the same rotation process of the measured object.

4. The method for measuring the three-dimensional surface topography of a wafer according to claim 1, wherein: The step S3 comprises: S31. Obtain ideal height data Z3: According to the stage height data Z2 recorded by the second measuring probe, an ideal height curve is fitted to obtain the ideal height data at the corresponding position; S32. Define the fluctuation error ΔZ: The difference between the actual measured stage height data Z2 and the ideal height data Z3 is calculated to represent the fluctuation error of the stage.

5. The method for measuring the three-dimensional surface topography of a wafer according to claim 1, wherein: The step S4 compares the actually measured loading platform height data Z2 with the ideal height data Z3 to obtain the fluctuation error of the loading plate at different positions, where the fluctuation error ΔZ=Z2-Z3.

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