Thin film stress measurement method, device, system, medium and program

Abstract

The embodiment of the invention provides a thin film stress measurement method, device and system, a medium and a program. The measurement method comprises the following steps: acquiring position information of a plurality of first measurement points of a wafer before film coating and first detection information of each first measurement point; determining a first offset according to the first detection information of each first measurement point; determining a first curvature radius according to the position information of each first measurement point and the first offset corresponding to each first measurement point; acquiring position information of a plurality of second measurement points of the coated wafer and second detection information of each second measurement point; determining a second offset according to the second detection information of each second measurement point; determining a second curvature radius according to the position information of each second measurement point and the second offset corresponding to each second measurement point; and determining the stress of the coated wafer according to the first curvature radius and the second curvature radius. By adopting the technical scheme, the precision of the stress value can be improved.

Description

Technical Field

[0001] The embodiments of the present disclosure relate to the field of wafer detection technology, and in particular, to a thin film stress measurement method, device, system, medium and program. Background Art

[0002] In the semiconductor manufacturing process, a thin film needs to be formed on the surface of the wafer to conduct signals. After different thin films are deposited on the surface of the wafer, stress will inevitably be generated when the ambient temperature changes because different materials have different expansion coefficients.

[0003] At present, the stress value of the wafer after coating is determined by irradiating the wafer surface with laser and detecting the reflected light through the position sensor. However, the stress value obtained by the above measurement method depends on the installation accuracy of the optical path and the measurement accuracy of the position sensor. When the optical path of the laser has an error or the measurement accuracy of the position sensor becomes low, the accuracy of the measured stress value is low and the correct measurement result cannot be obtained.

[0004] On this basis, how to provide a technical solution to improve the accuracy of stress values ​​has become a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0005] In view of this, the embodiments of the present disclosure provide a thin film stress measurement method, device, system, medium and program, which can improve the accuracy of stress values.

[0006] The present disclosure provides a method for measuring film stress, including:

[0007] Obtain position information of a plurality of first measurement points on the wafer surface of the wafer before coating, and first detection information of each first measurement point; determine a first offset of each first measurement point relative to the wafer surface according to the first detection information of each first measurement point; wherein one first measurement point corresponds to one first offset; determine a first radius of curvature of the wafer before coating according to the position information of each first measurement point and the first offset corresponding to each first measurement point; obtain position information of a plurality of second measurement points on the thin film surface of the wafer after coating, and second detection information of each second measurement point; determine a second offset of each second measurement point relative to the thin film surface according to the second detection information of each second measurement point; wherein one second measurement point corresponds to one second offset; determine a second radius of curvature of the wafer after coating according to the position information of each second measurement point and the second offset corresponding to each second measurement point; determine stress of the wafer after coating according to the first radius of curvature and the second radius of curvature.

[0008] Optionally, the first detection information of the first measuring point includes a first liquid level change value corresponding to the first measuring point, and the first liquid level value is used to characterize the warping degree of the first measuring point relative to the wafer surface;

[0009] The method of obtaining first detection information of each first measurement point on the wafer surface of the wafer before coating includes: obtaining a first detection signal when each first measurement point on the wafer surface of the wafer before coating is not touched, the first detection signal including a first pressure value when each first measurement point on the wafer surface of the wafer before coating is not touched; obtaining a second detection signal when each first measurement point on the wafer surface of the wafer before coating is touched, the second detection signal including a second pressure value when each first measurement point on the wafer surface of the wafer before coating is touched; determining a pressure difference between the first pressure value and the second pressure value according to the first detection signal and the second detection signal corresponding to each first measurement point on the wafer surface of the wafer before coating; and determining a first liquid level change value corresponding to each first measurement point on the wafer surface of the wafer before coating according to the pressure difference between the first pressure value and the second pressure value.

[0010] Optionally, determining the first offset of each first measurement point relative to the wafer surface based on the first detection information of each first measurement point includes: determining the first offset of each first measurement point relative to the wafer surface based on a correspondence between a preset liquid level change value and the offset.

[0011] Optionally, determining the first radius of curvature of the wafer before coating according to the position information of each first measurement point and the first offset corresponding to each first measurement point includes: performing fitting processing using a preset fitting algorithm according to the position information of each first measurement point and the first offset corresponding to each first measurement point to obtain a first fitting circle corresponding to the wafer surface of the wafer before coating; and determining the radius of the first fitting circle as the first radius of curvature of the wafer before coating.

[0012] Optionally, the second detection information of the second measuring point includes a second liquid level change value corresponding to the second measuring point, and the second liquid level value is used to characterize the warping degree of the second measuring point relative to the film surface;

[0013] The method of obtaining second detection information of each second measurement point on the thin film surface of the wafer after coating includes: obtaining a third detection signal when each second measurement point on the thin film surface of the wafer after coating is not touched, the third detection signal including a third pressure value when each second measurement point on the thin film surface of the wafer after coating is not touched; obtaining a fourth detection signal when each second measurement point on the thin film surface of the wafer after coating is touched, the fourth detection signal including a fourth pressure value when each second measurement point on the thin film surface of the wafer after coating is touched; determining a pressure difference between the third pressure value and the fourth pressure value according to the third detection signal and the fourth detection signal corresponding to each second measurement point on the thin film surface of the wafer after coating; and determining a second liquid level change value corresponding to each second measurement point on the thin film surface of the wafer after coating according to the pressure difference between the third pressure value and the fourth pressure value.

[0014] Optionally, determining the second offset of each second measuring point relative to the film surface according to the second detection information of each second measuring point includes: determining the second offset of each second measuring point relative to the film surface according to a preset correspondence between a liquid level change value and the offset.

[0015] Optionally, determining the second radius of curvature of the wafer after coating according to the position information of each second measurement point and the second offset corresponding to each second measurement point includes: performing fitting processing using a preset fitting algorithm according to the position information of each second measurement point and the second offset corresponding to each second measurement point to obtain a second fitting circle corresponding to the thin film surface of the wafer after coating; and determining the radius of the second fitting circle as the second radius of curvature of the wafer after coating.

[0016] Optionally, the plurality of first measurement points are arranged along the same diameter of the wafer surface of the wafer before coating, and the plurality of second measurement points are arranged along the same diameter of the thin film surface of the wafer after coating.

[0017] The embodiment of the present disclosure also provides a thin film stress measurement device, including: a data acquisition unit, adapted to acquire position information of a plurality of first measurement points on the wafer surface of a wafer before coating; and adapted to acquire position information of a plurality of second measurement points on the thin film surface of a wafer after coating; a processing unit, adapted to acquire first detection information of each first measurement point on the wafer surface of the wafer before coating, and determine a first offset of each first measurement point relative to the wafer surface according to the first detection information of each first measurement point; wherein one first measurement point corresponds to one first offset; and, according to the position information of each first measurement point, and each The invention relates to a method for determining a first curvature radius of the wafer before coating according to a first offset corresponding to each first measurement point; and obtaining second detection information of each second measurement point on the thin film surface of the wafer after coating, and determining the second offset of each second measurement point relative to the thin film surface according to the second detection information of each second measurement point; wherein one second measurement point corresponds to one second offset; and determining the second curvature radius of the wafer after coating according to the position information of each second measurement point and the second offset corresponding to each second measurement point; and determining the stress of the wafer after coating according to the first curvature radius and the second curvature radius.

[0018] The disclosed embodiment also provides a thin film stress measurement system, comprising: a processor and a detector; the processor is adapted to generate a first motion control signal and a second motion control signal; and, based on first detection information provided by the detector, determining a first offset of each first measurement point on the wafer surface of the wafer before coating relative to the wafer surface; wherein one first measurement point corresponds to one first offset; and, based on second detection information provided by the detector, determining a second offset of each second measurement point on the thin film surface of the wafer after coating relative to the thin film surface; wherein one second measurement point corresponds to one second offset; and, based on position information of each first measurement point on the wafer surface of the wafer before coating and the first offset corresponding to each first measurement point, determining a first radius of curvature of the wafer before coating, and determining a first radius of curvature of the thin film surface of the wafer after coating. The method comprises the following steps of: determining the second radius of curvature of the wafer after coating based on the position information of each second measurement point on the surface and the second offset corresponding to each second measurement point; and determining the stress of the wafer after coating based on the first radius of curvature and the second radius of curvature; the detector is suitable for responding to the first motion control signal, moving along the wafer surface of the wafer before coating with a preset first step length, and contacting multiple first measurement points on the wafer surface of the wafer before coating to obtain first detection information of each first measurement point, and outputting the first detection information to the processor; and being suitable for responding to the second motion control signal, moving along the wafer surface after coating with a preset second step length, and contacting multiple second measurement points on the thin film surface of the wafer after coating to obtain second detection information of each second measurement point, and outputting the second detection information to the processor.

[0019] Optionally, the first detection information of the first measuring point includes a first liquid level change value corresponding to the first measuring point, and the first liquid level value is used to characterize the warping degree of the first measuring point relative to the wafer surface;

[0020] The detector is suitable for generating a first detection signal including a first pressure value before contacting each first measurement point on the wafer surface of the wafer before coating; and generating a second detection signal including a second pressure value when contacting each first measurement point on the wafer surface of the wafer before coating; the processor is suitable for determining the pressure difference between the first pressure value and the second pressure value according to the first detection signal and the second detection signal corresponding to each first measurement point on the wafer surface of the wafer before coating; and determining the first liquid level change value corresponding to each first measurement point on the wafer surface of the wafer before coating according to the pressure difference between the first pressure value and the second pressure value.

[0021] Optionally, the second detection information of the second measuring point includes a second liquid level change value corresponding to the second measuring point, and the second liquid level value is used to characterize the warping degree of the second measuring point relative to the film surface;

[0022] The detector is suitable for generating a third detection signal including a third pressure value before contacting each second measurement point on the thin film surface of the wafer after coating; and generating a fourth detection signal including a fourth pressure value when contacting each second measurement point on the thin film surface of the wafer after coating; the processor is suitable for determining the pressure difference between the third pressure value and the fourth pressure value according to the third detection signal and the fourth detection signal corresponding to each second measurement point on the thin film surface of the wafer after coating; and determining the second liquid level change value corresponding to each second measurement point on the thin film surface of the wafer after coating according to the pressure difference between the third pressure value and the fourth pressure value.

[0023] Optionally, there are multiple detectors; before the wafer is coated, the position of each detector corresponds to the position of each measurement point on the wafer surface before coating; after the wafer is coated, the position of each detector corresponds to the position of each measurement point on the wafer surface after coating.

[0024] Optionally, the detector includes: a cross bar electrically connected to the processor; a hydraulic cylinder arranged on the cross bar, wherein the hydraulic cylinder has liquid; a sensor electrically connected to the processor and arranged in the hydraulic cylinder, for detecting changes in the liquid level in the hydraulic cylinder; a probe slidingly matched with the hydraulic cylinder, wherein when the probe contacts each first measuring point on the wafer surface of the wafer before coating, the liquid level in the hydraulic cylinder changes; and when the probe contacts each second measuring point on the thin film surface of the wafer after coating, the liquid level in the hydraulic cylinder changes.

[0025] The embodiment of the present disclosure further provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed, the steps of the thin film stress measurement method as described above are executed.

[0026] The embodiment of the present disclosure further provides a computer program product, comprising computer instructions, which, when executed by a processor, implement the steps of the thin film stress measurement method as described above.

[0027] By adopting the thin film stress measurement method provided by the embodiment of the present disclosure, by obtaining the first detection information of each first measurement point on the wafer surface of the wafer before coating, the first offset of each first measurement point relative to the wafer surface can be determined according to the first detection information of each first measurement point; and then the first curvature radius of the wafer before coating can be determined according to the position information of each first measurement point. And, by obtaining the second detection information of each second measurement point on the wafer surface of the wafer after coating, the second offset of each second measurement point relative to the film surface can be determined according to the second detection information of each second measurement point; and then the second curvature radius of the wafer after coating can be determined according to the position information of each second measurement point. According to the first curvature radius of the wafer before coating and the second curvature radius of the wafer after coating, the stress of the wafer after coating can be determined. By adopting the above measurement method, by obtaining the first offset and position information of each first measurement point, and the second offset and position information of each second measurement point, the first curvature radius and the first curvature radius with higher accuracy can be obtained without considering the installation accuracy of the optical path, so that the accuracy of the stress value can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the disclosure or the prior art description will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0029] Figure 1 A schematic diagram of the principle of thin film stress measurement is shown;

[0030] Figure 2 A flow chart of a thin film stress measurement method according to an embodiment of the present disclosure is shown;

[0031] Figure 3 A flow chart for obtaining a first liquid level change value in an embodiment of the present disclosure is shown;

[0032] Figure 4 A schematic structural diagram of a thin film stress measurement device according to an embodiment of the present disclosure is shown;

[0033] Figure 5 A schematic structural diagram of a thin film stress measurement system according to an embodiment of the present disclosure is shown;

[0034] Figure 6 for Figure 5 Schematic diagram of the enlarged structure corresponding to point A in the middle. DETAILED DESCRIPTION

[0035] As described in the background art, in the semiconductor manufacturing process, it is necessary to measure the film stress of the wafer after coating. This is because: when the expansion coefficient of the wafer is greater than the expansion coefficient of the film material, compressive stress will be generated; when the expansion coefficient of the wafer is less than the expansion coefficient of the film material, tensile stress will be generated.

[0036] When the stress is too large, it exceeds the strength of the film, causing film cracking, peeling and deformation, as well as bulging or protrusions of the metal coating. Therefore, it is necessary to measure the overall film stress of the wafer after coating to ensure that the wafer will not have large errors due to film stress in the subsequent process flow, affecting the chip quality.

[0037] See also Figure 1 A schematic diagram of the principle of thin film stress measurement is shown in FIG. Figure 1 As shown, a thin film 11 is provided on a wafer 10, and a laser 12 emits a laser with a certain wavelength and irradiates the surface of the thin film 11. After being reflected by the surface of the thin film 11, the reflected light is transmitted to a position sensor 14 through a reflector 13, and the position sensor 14 can display the position of the reflected light.

[0038] During the measurement process, by changing the position of the laser 12, the position of the laser on the surface of the film 11 can be changed, and then the positions of multiple reflected lights can be displayed on the position sensor 14 to obtain the displacement length between adjacent incident points.

[0039] The radius of curvature of the wafer after coating can be determined based on the displacement length between adjacent incident points, the optical path length of the measuring optical path, and the diameter of the wafer. Furthermore, the stress of the wafer after coating can be determined based on the radius of curvature of the wafer before coating and the Stoney formula.

[0040] The inventors found that the installation accuracy of the optical path and the measurement accuracy of the position sensor directly affect the accuracy of the curvature radius of the wafer after coating. Therefore, the laser needs to be transmitted along the set optical path. When an error occurs in the optical path of the laser or the measurement accuracy of the position sensor becomes low, the accuracy of the measured stress value is low and the correct measurement result cannot be obtained.

[0041] In order to solve the above technical problems, the embodiments of the present disclosure provide a thin film stress measurement method. By obtaining the first offset and position information of each first measurement point, and the second offset and position information of each second measurement point, there is no need to consider the installation accuracy of the optical path. A first curvature radius and a second curvature radius with higher accuracy can be obtained, thereby improving the accuracy of the stress value.

[0042] In order to enable those skilled in the art to better understand the inventive concept, working principle and advantages of the embodiments of the present disclosure, the thin film stress measurement method in the embodiments of the present disclosure is exemplarily described below.

[0043] See also Figure 2 Flow chart of a method for measuring film stress in an embodiment of the present disclosure is shown in FIG. In some embodiments of the present disclosure, as Figure 2 As shown, the film stress can be measured according to the following steps:

[0044] S11, obtaining position information of a plurality of first measurement points on the wafer surface of the wafer before coating, and first detection information of each first measurement point.

[0045] Specifically, the positions of the multiple first measurement points on the wafer surface of the wafer before coating are different, and accordingly, the first detection information corresponding to each first measurement point is also different. By obtaining the first detection information of the first measurement points at different positions, the state of the wafer surface of the wafer before coating can be determined more accurately, thereby improving the accuracy of the first radius of curvature.

[0046] In some examples, multiple first measurement points can be arranged along the same diameter of the wafer surface of the wafer before coating, that is, multiple first measurement points are distributed on the same line segment. Since the diameter is the symmetry axis of the wafer surface, setting the first measurement point on the diameter can better reflect the overall situation of the wafer surface.

[0047] In some examples, the distance between any two first measurement points among the plurality of first measurement points may be the same or different. The embodiment of the present disclosure does not impose any limitation on the distance between adjacent first measurement points.

[0048] In some examples, in order to reduce computational complexity and improve measurement efficiency, the center of the wafer surface of the wafer before coating can be used as the measurement point; or the center of the wafer surface of the wafer before coating and points on both sides of the center and on the circumference can be used as measurement points, that is, at least the position information and first detection information of three first measurement points can be obtained.

[0049] In some optional examples, the plurality of first measurement points may be randomly distributed on the wafer surface of the wafer before coating. The embodiment of the present disclosure does not impose any limitation on the distribution positions of the first measurement points.

[0050] S12, determining a first offset of each first measuring point relative to the wafer surface according to first detection information of each first measuring point.

[0051] Specifically, the first detection information can reflect the morphological state of the wafer surface at the current position. Based on the first detection information of each first measurement point, the change of each first measurement point relative to the wafer surface (which can be considered as a reference plane) can be determined, so that the corresponding first offset can be obtained, that is, the degree of warping of the position of the first measurement point relative to the wafer surface.

[0052] In some examples, a first measurement point corresponds to a first offset.

[0053] S13, determining a first radius of curvature of the wafer before coating according to the position information of each first measuring point and the first offset corresponding to each first measuring point.

[0054] Specifically, by obtaining the first offset of the first measurement point at different positions, the overall morphology of the wafer surface can be reflected, and then based on the position information of each first measurement point and the first offset corresponding to each first measurement point, a preset calculation method can be used to obtain the first curvature radius of the wafer before coating.

[0055] S14, obtaining position information of a plurality of second measurement points on the thin film surface of the wafer after coating, and second detection information of each second measurement point.

[0056] Specifically, the positions of the plurality of second measurement points on the film surface of the wafer after coating are different, and accordingly, the second detection information corresponding to each second measurement point is also different. By obtaining the second detection information of the second measurement points at different positions, the state of the film surface of the wafer after coating can be determined more accurately, thereby improving the accuracy of the second radius of curvature.

[0057] In some examples, multiple second measurement points can be arranged along the same diameter of the film surface of the wafer after coating, that is, multiple second measurement points are distributed on the same line segment. Since the diameter is the symmetry axis of the film surface, setting the second measurement points on the diameter can better reflect the overall situation of the film surface.

[0058] In some examples, the distance between any two second measurement points in the plurality of second measurement points may be the same or different. The embodiment of the present disclosure does not impose any limitation on the distance between adjacent second measurement points.

[0059] In some examples, in order to reduce computational complexity and improve measurement efficiency, the center of the thin film surface of the wafer after coating can be used as the measurement point; or the center of the thin film surface of the wafer after coating and points on both sides of the center and on the circumference can be used as measurement points, that is, at least the position information and second detection information of three second measurement points can be obtained.

[0060] In some examples, along the normal direction of the wafer surface, the second measurement point is located directly above the first measurement point, that is, their projections on the wafer surface completely overlap.

[0061] In some optional examples, the plurality of second measurement points may be randomly distributed on the film surface of the wafer after coating. The embodiment of the present disclosure does not impose any limitation on the distribution positions of the second measurement points.

[0062] S15, determining a second offset of each second measuring point relative to the film surface according to the second detection information of each second measuring point.

[0063] Specifically, the second detection information can reflect the morphological state of the film surface at the current position. Based on the second detection information of each second measurement point, the change of each second measurement point relative to the film surface (which can be considered as a reference plane) can be determined, so that the corresponding second offset can be obtained, that is, the degree of warping of the position of the second measurement point relative to the film surface.

[0064] In some examples, a second measurement point corresponds to a second offset.

[0065] S16, determining a second radius of curvature of the wafer after coating according to the position information of each second measuring point and the second offset corresponding to each second measuring point.

[0066] Specifically, by obtaining the second offset of the second measurement point at different positions, the overall morphology of the film surface can be reflected, and then based on the position information of each second measurement point and the second offset corresponding to each second measurement point, a preset calculation method can be used to obtain the second curvature radius of the wafer after coating.

[0067] S17, determining the stress of the wafer after coating according to the first radius of curvature and the second radius of curvature.

[0068] Specifically, by adopting steps S11 to S16, the first radius of curvature of the wafer before coating and the second radius of curvature of the wafer after coating can be obtained, and then the stress of the wafer after coating can be obtained by adopting a preset calculation method.

[0069] Therefore, by adopting the thin film stress measurement method in the embodiment of the present disclosure, the stress of the wafer after coating can be determined by obtaining the first offset and position information of each first measurement point, and the second offset and position information of each second measurement point. The implementation method is simple and there is no need to consider the installation accuracy of the optical path, thereby reducing the difficulty of stress measurement.

[0070] In some embodiments of the present disclosure, the first detection information of the first measurement point may include a first liquid level change value corresponding to the first measurement point. By measuring the first liquid level change value corresponding to each first measurement point, the warping degree of the position of the first measurement point relative to the wafer surface can be determined, that is, the height information of the position of the first measurement point relative to the wafer surface.

[0071] In some examples, when obtaining first detection information (such as a first liquid level change value) of each first measurement point on the wafer surface of the wafer before coating, a plurality of methods can be used to determine a first offset of each first measurement point relative to the wafer surface.

[0072] As an example, there is a corresponding relationship between the liquid level change value and the offset. According to the preset corresponding relationship between the liquid level change value and the offset, the first offset of each first measurement point relative to the wafer surface can be determined.

[0073] In some embodiments of the present disclosure, the relationship between the liquid level change value and the offset can be expressed as:

[0074] Y=μ(A1-A i ) (1)

[0075] Wherein, Y represents the offset of the first measuring point relative to the wafer surface; μ represents the proportional coefficient between the liquid level change value and the offset; A1 represents the liquid level change value of the first measuring point; A i Indicates the liquid level change value of other first measuring points except A1.

[0076] The corresponding relationship between the liquid level change value and the offset can be obtained in the following manner: while measuring the first offset of the first measurement point at different positions relative to the wafer surface, the liquid level change value corresponding to each first offset is obtained. According to a plurality of first offsets and liquid level change values ​​having corresponding relationships, a straight line is fitted through multivariate linear regression analysis or nonlinear regression analysis, and the tangent slope of the straight line is used as a functional relationship between the first offset and the liquid level change value to determine the corresponding relationship between the first offset and the liquid level change value, that is, the corresponding relationship between the first liquid level change value and the offset is established.

[0077] Based on this, when obtaining the first detection information of each first measurement point on the wafer surface of the wafer before coating, the first offset corresponding to the first liquid level change value can be automatically obtained according to the correspondence between the liquid level change value and the offset, without the need for manual processing, thereby improving the calculation efficiency and the accuracy of the calculated first offset.

[0078] In an alternative example, see Figure 3 A flow chart for obtaining a first liquid level change value in an embodiment of the present disclosure is shown in FIG. Figure 3 As shown, the following steps can be performed:

[0079] S21, obtaining first detection signals when each first measurement point on the wafer surface of the wafer before coating is not contacted.

[0080] Specifically, when the first measurement points on the wafer surface of the wafer before coating are not contacted, the measuring device for measuring the first liquid level change value is in an initial state. At this time, the measuring device can generate a corresponding first detection signal to indicate the initial state of the measuring device.

[0081] In some examples, the first detection signal may include a first pressure value when each first measurement point on the wafer surface of the wafer before coating is not contacted, that is, an initial pressure value corresponding to the measuring device itself when the measuring device does not contact the first measurement point.

[0082] S22, obtaining second detection signals when each first measurement point on the wafer surface of the wafer before coating is contacted.

[0083] Specifically, when contacting each first measurement point on the wafer surface of the wafer before coating, the state of the measuring device will change (for example, the liquid level in the measuring device changes). At this time, the measuring device can generate a corresponding second detection signal to indicate the impact of each first measurement point on the measuring device.

[0084] In some examples, the second detection signal may include a second pressure value when each first measurement point on the wafer surface of the wafer before coating is contacted. That is, when the measuring device contacts the first measurement point, the pressure value changes under the action of the first measurement point, and the second pressure value obtained at this time is the current pressure value corresponding to the measuring device itself.

[0085] S23, determining a pressure difference between the first pressure value and the second pressure value according to the first detection signal and the second detection signal corresponding to each first measurement point on the wafer surface of the wafer before coating.

[0086] S24, determining first liquid level change values ​​corresponding to first measurement points on the wafer surface of the wafer before coating according to the pressure difference between the first pressure value and the second pressure value.

[0087] Specifically, the pressure difference between the first pressure value and the second pressure value can characterize the magnitude of the liquid level change. By calculating the pressure difference between the first pressure value and the second pressure value, the liquid level change caused by contact with each first measuring point can be determined, and then the first liquid level change value corresponding to each first measuring point can be determined.

[0088] That is to say, the embodiment of the present disclosure can determine the pressure difference value by measuring the pressure value before and after contacting each first measurement point, and based on the pressure difference value, the first liquid level change value can be determined. Through relationship mapping, the first offset of each first measurement point can be determined. Since the first liquid level change value is less affected by the external environment (such as temperature, air pressure), it can provide a very stable measurement result, thereby improving the accuracy of the first offset.

[0089] In some examples, for different liquids, when the liquid level changes, the pressure difference caused is different. In this case, when determining the type of liquid used, the first liquid level change value corresponding to each first measurement point is determined according to the relationship between the pressure difference and the liquid level change.

[0090] In some embodiments of the present disclosure, when the first offset corresponding to each first measurement point is determined, the first radius of curvature of the wafer before coating can be determined based on the position information of each first measurement point.

[0091] In some examples, the first fitting circle corresponding to the wafer surface of the wafer before coating can be determined based on the position information of each first measurement point and the first offset corresponding to each first measurement point, and then the radius of the first fitting circle is used as the first curvature radius of the wafer before coating.

[0092] In an optional example, a preset fitting algorithm can be used to perform fitting processing based on the position information of each first measurement point and the first offset corresponding to each first measurement point to obtain a first fitting circle corresponding to the wafer surface of the wafer before coating; and the radius of the first fitting circle is determined as the first curvature radius of the wafer before coating.

[0093] Specifically, the position information of one of the multiple first measurement points can be used as the starting point, and this point can be used as the reference point. According to a preset fitting algorithm (such as the least squares method), the other first measurement points can be fitted to obtain a first fitting circle, and the radius of the first fitting circle can be used as the first curvature radius.

[0094] In some examples, when performing the fitting process, the coordinate axis along the wafer surface may be used as the X-axis, and the coordinate axis perpendicular to the wafer surface may be used as the Y-axis.

[0095] In some examples, the “first fitting circle” may be a whole circle or a portion of a circle, and the embodiments of the present disclosure do not impose any limitation on this.

[0096] Since a preset fitting algorithm is adopted, a fitting circle reflecting the wafer surface can be obtained, and the first curvature radius determined can more accurately reflect the actual state of the wafer surface, and the stress accuracy can be improved.

[0097] In some embodiments of the present disclosure, the second detection information of the second measuring point may include a second liquid level change value corresponding to the second measuring point. By measuring the second liquid level change value corresponding to each second measuring point, the degree of warping of the position of the second measuring point relative to the film surface, that is, the height information of the position of the second measuring point relative to the film surface can be determined.

[0098] In some examples, when obtaining second detection information (such as a second liquid level change value) of each second measurement point on the thin film surface of the wafer after coating, a plurality of methods can be used to determine a second offset of each second measurement point relative to the thin film surface.

[0099] As an example, there is a corresponding relationship between the liquid level change value and the offset. According to the preset corresponding relationship between the liquid level change value and the offset, the second offset of each second measurement point relative to the film surface can be determined. The confirmation method of the second offset can refer to the description of the first offset, which will not be repeated here.

[0100] In the embodiment of the present disclosure, the corresponding relationship between the liquid level change value and the offset can be obtained in the following manner: while measuring the second offset of the second measuring point at different positions relative to the film surface, the liquid level change value corresponding to each second offset is obtained. According to a plurality of second offsets and liquid level change values ​​having corresponding relationships, a straight line is fitted through multivariate linear regression analysis or nonlinear regression analysis, and the tangent slope of the straight line is used as a functional relationship between the second offset and the liquid level change value to determine the corresponding relationship between the second offset and the liquid level change value, that is, the corresponding relationship between the second liquid level change value and the offset is established.

[0101] Based on this, when obtaining the second detection information of each second measurement point on the thin film surface of the wafer after coating, the second offset corresponding to the second liquid level change value can be automatically obtained according to the correspondence between the liquid level change value and the offset, without the need for manual processing, thereby improving the calculation efficiency and the accuracy of the calculated second offset.

[0102] In an optional example, the second offset of each second measurement point relative to the film surface may be determined in the following manner.

[0103] Obtain a third detection signal when each second measurement point on the thin film surface of the wafer after coating is not touched; obtain a fourth detection signal when each second measurement point on the thin film surface of the wafer after coating is touched; determine the pressure difference between the third pressure value and the fourth pressure value according to the third detection signal and the fourth detection signal corresponding to each second measurement point on the thin film surface of the wafer after coating; determine the second liquid level change value corresponding to each second measurement point on the thin film surface of the wafer after coating according to the pressure difference between the third pressure value and the fourth pressure value.

[0104] Specifically, when the second measurement points on the thin film surface of the wafer after coating are not contacted, the measuring device for measuring the second liquid level change value is in an initial state. At this time, the measuring device can generate a corresponding third detection signal to indicate the initial state of the measuring device.

[0105] In some examples, the third detection signal may include a third pressure value when each second measurement point on the film surface of the wafer after coating is not contacted, that is, an initial pressure value corresponding to the measuring device itself when the measuring device does not contact the second measurement point.

[0106] Afterwards, when the second measurement points on the thin film surface of the wafer after coating are contacted, the state of the measuring device will change (for example, the liquid level in the measuring device changes). At this time, the measuring device can generate a corresponding fourth detection signal to indicate the impact of each second measurement point on the measuring device.

[0107] In some examples, the fourth detection signal may include a fourth pressure value when each second measurement point on the film surface of the wafer after coating is contacted. That is, when the measuring device contacts the second measurement point, the pressure value changes under the action of the second measurement point, and the fourth pressure value obtained at this time is the current pressure value corresponding to the measuring device itself.

[0108] Next, according to the third detection signal and the fourth detection signal corresponding to each second measurement point on the thin film surface of the wafer after coating, the pressure difference between the third pressure value and the fourth pressure value can be determined, and then based on the pressure difference, the second liquid level change value corresponding to each second measurement point on the thin film surface of the wafer after coating can be determined.

[0109] Specifically, the pressure difference between the third pressure value and the fourth pressure value can characterize the magnitude of the liquid level change. By calculating the pressure difference between the third pressure value and the fourth pressure value, the liquid level change caused by contact with each second measuring point can be determined, and then the second liquid level change value corresponding to each second measuring point can be determined.

[0110] That is to say, the embodiment of the present disclosure can determine the pressure difference value by measuring the pressure value before and after contacting each second measurement point, and based on the pressure difference value, the second liquid level change value can be determined. Through relationship mapping, the second offset of each second measurement point can be determined. Since the second liquid level change value is less affected by the external environment (such as temperature, air pressure), it can provide a very stable measurement result, thereby improving the accuracy of the second offset.

[0111] In some examples, for different liquids, when the liquid level changes, the pressure difference caused is different. In this case, when determining the type of liquid used, the second liquid level change value corresponding to each second measurement point is determined based on the relationship between the pressure difference and the liquid level change.

[0112] In some embodiments of the present disclosure, when the second offset corresponding to each second measurement point is determined, the second radius of curvature of the wafer after coating can be determined based on the position information of each second measurement point.

[0113] In some examples, the second fitting circle corresponding to the thin film surface of the wafer after coating can be determined based on the position information of each second measurement point and the second offset corresponding to each second measurement point, and then the radius of the second fitting circle is used as the second curvature radius of the wafer after coating.

[0114] In an optional example, a preset fitting algorithm can be used to perform fitting processing based on the position information of each second measurement point and the first offset corresponding to each second measurement point to obtain a second fitting circle corresponding to the thin film surface of the wafer after coating; and the radius of the second fitting circle is determined as the second curvature radius of the wafer after coating.

[0115] Specifically, the position information of one of the multiple second measurement points can be used as a reference point, and with this point as the starting point, the other second measurement points can be fitted according to a preset fitting algorithm (such as the least squares method) to obtain a second fitting circle, and the radius of the second fitting circle is used as the second curvature radius.

[0116] In some examples, when performing the fitting process, the coordinate axis along the film surface may be used as the X-axis, and the coordinate axis perpendicular to the film surface may be used as the Y-axis.

[0117] In some examples, the “second fitting circle” may be a whole circle or a portion of a circle, and the embodiments of the present disclosure do not impose any limitation on this.

[0118] Since a preset fitting algorithm is adopted, a fitting circle reflecting the film surface can be obtained, and the second curvature radius determined thereby can more accurately reflect the actual state of the film surface, thereby improving stress accuracy.

[0119] By adopting the above scheme, the first radius of curvature of the wafer before coating can be determined according to the first offset and position information of each first measuring point; and the second radius of curvature of the wafer after coating can be determined according to the second offset and position information of each second measuring point, and then the stress of the wafer after coating can be determined according to the first radius of curvature and the second radius of curvature.

[0120] In some examples of the present disclosure, after determining the first radius of curvature and the second radius of curvature, the stress of the wafer after coating can be calculated using the Stoney formula.

[0121] As an example, the first radius of curvature R1 and the second radius of curvature R2 can be substituted into the Stoney formula to obtain the stress of the wafer after coating:

[0122]

[0123] in, represents the elastic modulus of the wafer, t s Indicates the thickness of the wafer, t f Indicates the thickness of the film layer on the wafer surface.

[0124] The present disclosure also provides a thin film stress measurement device corresponding to the above-mentioned thin film stress measurement method, which is described in detail below through specific embodiments with reference to the accompanying drawings.

[0125] See also Figure 4 The structure diagram of a thin film stress measurement device in an embodiment of the present disclosure is shown in FIG. Figure 4 As shown, the thin film stress measuring device 100 may include:

[0126] The data acquisition unit 110 is adapted to acquire position information of a plurality of first measurement points on the wafer surface of the wafer before coating; and adapted to acquire position information of a plurality of second measurement points on the thin film surface of the wafer after coating;

[0127] The processing unit 120 is adapted to obtain first detection information of each first measurement point on the wafer surface of the wafer before coating, and determine the first offset of each first measurement point relative to the wafer surface according to the first detection information of each first measurement point; wherein one first measurement point corresponds to one first offset; and, determine the first radius of curvature of the wafer before coating according to the position information of each first measurement point and the first offset corresponding to each first measurement point; and, obtain second detection information of each second measurement point on the thin film surface of the wafer after coating, and determine the second offset of each second measurement point relative to the thin film surface according to the second detection information of each second measurement point; wherein one second measurement point corresponds to one second offset; and, determine the second radius of curvature of the wafer after coating according to the position information of each second measurement point and the second offset corresponding to each second measurement point; and, determine the stress of the wafer after coating according to the first radius of curvature and the second radius of curvature.

[0128] Specifically, the processing unit 120 can determine the first offset of each first measurement point relative to the wafer surface according to the first detection information of each first measurement point, and then determine the first curvature radius of the wafer before coating with the position information of each first measurement point acquired by the data acquisition unit 110; and the processing unit 120 can determine the second offset of each second measurement point relative to the film surface according to the second detection information of each second measurement point, and then determine the second curvature radius of the wafer after coating with the position information of each second measurement point acquired by the data acquisition unit 110. Therefore, the processing unit 120 can determine the stress of the wafer after coating according to the first curvature radius and the second curvature radius.

[0129] By using the above-mentioned thin film stress measurement device 100, the processing unit 120 can determine the stress of the wafer after coating based on the first offset and position information of each first measurement point, and the second offset and position information of each second measurement point. The implementation method is simple and there is no need to consider the installation accuracy of the optical path, thereby reducing the difficulty of stress measurement.

[0130] In some embodiments of the present disclosure, the first detection information of the first measurement point may include a first liquid level change value corresponding to the first measurement point. By measuring the first liquid level change value corresponding to each first measurement point, the warping degree of the position of the first measurement point relative to the wafer surface can be determined, that is, the height information of the position of the first measurement point relative to the wafer surface.

[0131] In some examples, when obtaining first detection information (such as a first liquid level change value) of each first measurement point on the wafer surface of the wafer before coating, a plurality of methods can be used to determine a first offset of each first measurement point relative to the wafer surface.

[0132] As an example, there is a corresponding relationship between the liquid level change value and the offset, and the processing unit pre-stores the corresponding relationship. When the first liquid level change value is obtained, the processing unit can determine the first offset of each first measurement point relative to the wafer surface based on the pre-set corresponding relationship between the liquid level change value and the offset.

[0133] Based on this, when obtaining the first detection information of each first measurement point on the wafer surface of the wafer before coating, the processing unit can automatically obtain the first offset corresponding to the first liquid level change value according to the correspondence between the liquid level change value and the offset, without the need for manual processing, thereby improving the computing efficiency and the accuracy of the calculated first offset.

[0134] Similarly, the processing unit may obtain the second offset in a manner similar to that of obtaining the first offset.

[0135] In some embodiments of the present disclosure, the processing unit can determine the pressure difference value by measuring the pressure value before and after contacting each first measurement point, and the first liquid level change value can be determined based on the pressure difference value. Through relationship mapping, the first offset of each first measurement point can be determined. Since the first liquid level change value is less affected by the external environment (such as temperature, air pressure), a very stable measurement result can be provided, thereby improving the accuracy of the first offset.

[0136] The scheme for determining the first liquid level change value may refer to the aforementioned example.

[0137] In some embodiments of the present disclosure, when determining the first offset corresponding to each first measurement point, the processing unit may determine the first radius of curvature of the wafer before coating according to the position information of each first measurement point.

[0138] Among them, the solution for determining the first radius of curvature of the wafer before coating can refer to the above example.

[0139] Similarly, the processing unit can determine the pressure difference value by measuring the pressure value before and after contacting each second measurement point, and the second liquid level change value can be determined based on the pressure difference value. Through relationship mapping, the second offset of each second measurement point can be determined. Since the second liquid level change value is less affected by the external environment (such as temperature, air pressure), it can provide a very stable measurement result, thereby improving the accuracy of the second offset.

[0140] The scheme for determining the second liquid level change value may refer to the aforementioned example.

[0141] Correspondingly, when determining the second offset corresponding to each second measuring point, the processing unit may determine the second radius of curvature of the wafer after coating according to the position information of each second measuring point.

[0142] Among them, the solution for determining the second radius of curvature of the wafer after coating can refer to the above example.

[0143] By adopting the above scheme, the processing unit can determine the first radius of curvature of the wafer before coating according to the first offset and position information of each first measuring point; and can determine the second radius of curvature of the wafer after coating according to the second offset and position information of each second measuring point. Then, the processing unit can determine the stress of the wafer after coating based on the first radius of curvature and the second radius of curvature obtained.

[0144] In some examples of the present disclosure, after determining the first radius of curvature and the second radius of curvature, the processing unit may calculate the stress of the wafer after coating using the Stoney formula.

[0145] To facilitate the implementation of the film stress measurement method in the above example, the present disclosure also provides a film stress measurement system, see Figure 5 The structure diagram of a thin film stress measurement system shown in the figure, the thin film stress measurement system may include: a processor X1 and a detector X2; wherein:

[0146] The processor X1 is adapted to generate a first motion control signal and a second motion control signal; and, based on the first detection information provided by the detector X2, determine the first offset of each first measurement point on the surface of the wafer W of the wafer before coating relative to the wafer surface; wherein one first measurement point corresponds to one first offset; and, based on the second detection information provided by the detector X2, determine the second offset of each second measurement point on the thin film surface of the wafer after coating relative to the thin film surface; wherein one second measurement point corresponds to one second offset; and, based on the position information of each first measurement point on the surface of the wafer W of the wafer before coating, and the first offset corresponding to each first measurement point, determine the first radius of curvature of the wafer W before coating, and based on the position information of each second measurement point on the thin film surface of the wafer after coating, and the second offset corresponding to each second measurement point, determine the second radius of curvature of the wafer after coating; and, based on the first radius of curvature and the second radius of curvature, determine the stress of the wafer after coating;

[0147] The detector X2 is adapted to respond to the first motion control signal, move along the wafer W surface of the wafer before coating with a preset first step length, and contact multiple first measurement points on the wafer W surface of the wafer before coating to obtain first detection information of each first measurement point, and output the first detection information to the processor X2; and is adapted to respond to the second motion control signal, move along the wafer surface after coating with a preset second step length, and contact multiple second measurement points on the thin film surface of the wafer after coating to obtain second detection information of each second measurement point, and output the second detection information to the processor X2.

[0148] Specifically, by making the detector X2 move along the surface of wafer W of the wafer before coating with a preset first step length, the detector X2 can output the first detection information at different positions on the surface of wafer W to the processor X1 when it contacts each first measurement point, and the processor X1 can determine the first radius of curvature accordingly; and by making the detector X2 move along the thin film surface of the wafer after coating with a preset second step length, the detector X2 can output the second detection information at different positions on the thin film surface to the processor X1 when it contacts each second measurement point, and the processor X1 can determine the second radius of curvature accordingly, and then the processor X1 can determine the stress of the wafer after coating according to the first radius of curvature and the second radius of curvature.

[0149] Among them, the processor X1 determines the first radius of curvature and the second radius of curvature, and determines the stress of the wafer after coating based on the first radius of curvature and the second radius of curvature, which can be seen from the above example.

[0150] In some embodiments of the present disclosure, when the distances between adjacent first measurement points are the same, the moving distance corresponding to the first step length may be the same as the distance between adjacent first measurement points to reduce the measurement difficulty.

[0151] Similarly, when the distances between adjacent second measurement points are the same, the moving distance corresponding to the second step length may be the same as the distance between adjacent second measurement points, so as to reduce the difficulty of measurement.

[0152] In some embodiments of the present disclosure, the first detection information of the first measurement point may include a first liquid level change value corresponding to the first measurement point, and the first liquid level value is used to characterize the warping degree of the first measurement point relative to the wafer surface.

[0153] In this case, the film stress measurement system may determine the first liquid level change value in the following manner, specifically including:

[0154] The detector is suitable for generating a first detection signal including a first pressure value before contacting each first measurement point on the wafer surface of the wafer before coating; and generating a second detection signal including a second pressure value when contacting each first measurement point on the wafer surface of the wafer before coating; the processor is suitable for determining the pressure difference between the first pressure value and the second pressure value according to the first detection signal and the second detection signal corresponding to each first measurement point on the wafer surface of the wafer before coating; and determining the first liquid level change value corresponding to each first measurement point on the wafer surface of the wafer before coating according to the pressure difference between the first pressure value and the second pressure value.

[0155] In short, the detector can generate a first detection signal and a second detection signal before and after contacting each first measuring point, and then the processor can determine the first liquid level change value by calculating the pressure difference value before and after the detector contacts each first measuring point. For the specific process, please refer to the above example.

[0156] Furthermore, the processor can determine the first offset of each first measurement point through relationship mapping. Since the first liquid level change value is less affected by the external environment (such as temperature, air pressure), a very stable measurement result can be provided, thereby improving the accuracy of the first offset.

[0157] Similarly, the second detection information of the second measuring point may include a second liquid level change value corresponding to the second measuring point, and the second liquid level value may be used to characterize the degree of warping of the second measuring point relative to the film surface.

[0158] In this case, the film stress measurement system may determine the second liquid level change value in the following manner, specifically including:

[0159] The detector is adapted to generate a third detection signal including a third pressure value before contacting each second measurement point on the film surface of the coated wafer; and to generate a fourth detection signal including a fourth pressure value when contacting each second measurement point on the film surface of the coated wafer;

[0160] The processor is suitable for determining the pressure difference between the third pressure value and the fourth pressure value based on the third detection signal and the fourth detection signal corresponding to each second measurement point on the thin film surface of the wafer after coating; and determining the second liquid level change value corresponding to each second measurement point on the thin film surface of the wafer after coating based on the pressure difference between the third pressure value and the fourth pressure value.

[0161] In short, the detector can generate a third detection signal and a fourth detection signal before and after contacting each second measurement point, and then the processor can determine the second liquid level change value by calculating the pressure difference value before and after the detector contacts each second measurement point. For the specific process, please refer to the above example.

[0162] Furthermore, the processor can determine the second offset of each second measurement point through relationship mapping. Since the second liquid level change value is less affected by the external environment (such as temperature, air pressure), a very stable measurement result can be provided, thereby improving the accuracy of the second offset.

[0163] In some examples of the present disclosure, a detector may be used to contact first measurement points located at different positions on the wafer surface during different time periods; and to contact second measurement points located at different positions on the film surface during different time periods.

[0164] In some examples, there are multiple detectors; before the wafer is coated, the position of each detector corresponds to the position of each measurement point on the wafer surface before coating; after the wafer is coated, the position of each detector corresponds to the position of each measurement point on the wafer surface after coating. That is, in the same period of time, the first measurement point located at a different position on the wafer surface is contacted; or, in the same period of time, the second measurement point located at a different position on the film surface is contacted to improve the measurement efficiency.

[0165] In some embodiments of the present disclosure, Figure 5 and Figure 6 , Figure 6 for Figure 5 The enlarged structural diagram corresponding to A in the figure is as follows: Figure 5 and Figure 6 As shown, the detector X2 may include:

[0166] A crossbar G electrically connected to the processor X1;

[0167] A hydraulic cylinder H disposed on the crossbar G, wherein the hydraulic cylinder H has a liquid therein;

[0168] A sensor S electrically connected to the processor X1 and disposed in the hydraulic cylinder H for detecting changes in the liquid level in the hydraulic cylinder H;

[0169] The probe P slides with the hydraulic cylinder H. When the probe P contacts each first measuring point on the wafer surface of the wafer before coating, the liquid level in the hydraulic cylinder H changes. Also, when the probe P contacts each second measuring point on the thin film surface of the wafer after coating, the liquid level in the hydraulic cylinder H changes.

[0170] Specifically, the hydraulic cylinder H is set on the cross bar G. When measuring, the initial position of the hydraulic cylinder H is calibrated so that the hydraulic cylinder H is located at the edge of the cross bar G (it can be understood that it can also be other positions). At the same time, the number of measuring points (including the first measuring point and the second measuring point) to be measured and the unit distance moved by the hydraulic cylinder H along the circumference of the cross bar G are set by the processor X2.

[0171] During measurement, the crossbar G first approaches the wafer W, and the hydraulic cylinder H moves along the crossbar G and the inner side of the crossbar G. When the crossbar G approaches the surface of the wafer W, the hydraulic cylinder H moves toward the wafer W, so that the probe P can contact the measurement point. Under the action of the wafer W, the probe P slides along the hydraulic cylinder H, and then squeezes the liquid in the hydraulic cylinder H, and the liquid level in the hydraulic cylinder H changes. After the liquid level stabilizes, pressure is generated due to the change in the liquid level. The sensor S can detect the pressure value and convert the pressure value into a liquid level change value to complete the measurement process of a measurement point.

[0172] After the measurement process is completed, the hydraulic cylinder H moves toward the side away from the wafer, and under the action of gravity, the probe P returns to its original state. Then, the hydraulic cylinder H measures the next measurement point according to the initially set moving distance until all measurement points are measured.

[0173] In some other examples, the position of the detector may be kept fixed, and the wafer may be moved so that the detector contacts each first measurement point and each second measurement point.

[0174] In some embodiments of the present disclosure, the processor may include a central processing unit (CPU), a graphics processing unit (GPU), a field programmable gate array (FPGA), etc.

[0175] The present disclosure further provides a computer-readable storage medium on which computer instructions are stored. When the computer instructions are executed, the thin film stress measurement method described in any of the above embodiments can be executed. For details, please refer to the above related content, which will not be repeated here.

[0176] Among them, the computer-readable storage medium may include any suitable type of memory unit, memory device, memory article, memory medium, storage device, storage article, storage medium and / or storage unit, such as memory, removable or non-removable medium, erasable or non-erasable medium, writable or rewritable medium, digital or analog medium, hard disk, floppy disk, compact disk read-only memory (CDROM), compact disk recordable (CD-R), compact disk rewritable (CD-RW), optical disk, magnetic medium, magneto-optical medium, removable memory card or disk, various types of digital versatile disks (DVD), magnetic tape, cassette, etc.

[0177] Furthermore, the computer instructions may include any suitable type of code implemented using any suitable high-level, low-level, object-oriented, visual, compiled and / or interpreted programming language, such as source code, compiled code, interpreted code, executable code, static code, dynamic code, encrypted code, etc.

[0178] The present invention also provides a computer program product, which may include computer instructions. When the computer instructions are executed by a processor, the thin film stress measurement method described in any of the above embodiments is implemented. For details, please refer to the above related content, which will not be repeated here.

[0179] Although the disclosure is as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A method for measuring film stress, characterized in that: include: Acquire position information of a plurality of first measurement points on the wafer surface of the wafer before coating, and first detection information of each first measurement point; Determine a first offset of each first measurement point relative to the wafer surface according to first detection information of each first measurement point, wherein one first measurement point corresponds to one first offset; Determine a first radius of curvature of the wafer before coating according to position information of each first measuring point and a first offset corresponding to each first measuring point; Acquire position information of a plurality of second measurement points on the thin film surface of the wafer after coating, and second detection information of each second measurement point; Determine the second offset of each second measuring point relative to the film surface according to the second detection information of each second measuring point, wherein one second measuring point corresponds to one second offset; Determine a second radius of curvature of the wafer after coating according to position information of each second measuring point and a second offset corresponding to each second measuring point; The stress of the wafer after coating is determined according to the first radius of curvature and the second radius of curvature.

2. The thin film stress measurement method according to claim 1, characterized in that: The first detection information of the first measuring point includes a first liquid level change value corresponding to the first measuring point, where the first liquid level value is used to characterize the warping degree of the first measuring point relative to the wafer surface; The step of obtaining first detection information of each first measurement point on the wafer surface of the wafer before coating includes: Acquire a first detection signal when each first measurement point on the wafer surface of the wafer before coating is not touched, wherein the first detection signal includes a first pressure value when each first measurement point on the wafer surface of the wafer before coating is not touched; Acquire a second detection signal when each first measurement point on the wafer surface of the wafer before coating is touched, wherein the second detection signal includes a second pressure value when each first measurement point on the wafer surface of the wafer before coating is touched; Determine a pressure difference between the first pressure value and the second pressure value according to first detection signals and second detection signals corresponding to first measurement points on the wafer surface of the wafer before coating; According to the pressure difference between the first pressure value and the second pressure value, first liquid level change values ​​corresponding to each first measuring point on the wafer surface of the wafer before coating are determined.

3. The thin film stress measurement method according to claim 2, characterized in that: The determining, according to the first detection information of each first measurement point, a first offset of each first measurement point relative to the wafer surface comprises: According to the preset corresponding relationship between the liquid level change value and the offset, the first offset of each first measuring point relative to the wafer surface is determined.

4. The thin film stress measurement method according to claim 1, characterized in that: Determining the first radius of curvature of the wafer before coating according to the position information of each first measuring point and the first offset corresponding to each first measuring point includes: According to the position information of each first measurement point and the first offset corresponding to each first measurement point, a preset fitting algorithm is used to perform fitting processing to obtain a first fitting circle corresponding to the wafer surface of the wafer before coating; The radius of the first fitting circle is determined as the first curvature radius of the wafer before coating.

5. The thin film stress measurement method according to claim 1, characterized in that: The second detection information of the second measuring point includes a second liquid level change value corresponding to the second measuring point, and the second liquid level value is used to characterize the warping degree of the second measuring point relative to the film surface; The step of obtaining second detection information of each second measurement point on the thin film surface of the wafer after coating includes: Acquire a third detection signal when each second measurement point on the thin film surface of the coated wafer is not touched, wherein the third detection signal includes a third pressure value when each second measurement point on the thin film surface of the coated wafer is not touched; Acquire a fourth detection signal when each second measurement point on the film surface of the coated wafer is contacted, wherein the fourth detection signal includes a fourth pressure value when each second measurement point on the film surface of the coated wafer is contacted; Determine the pressure difference between the third pressure value and the fourth pressure value according to the third detection signal and the fourth detection signal corresponding to each second measurement point on the thin film surface of the wafer after coating; According to the pressure difference between the third pressure value and the fourth pressure value, the second liquid level change value corresponding to each second measuring point on the thin film surface of the wafer after coating is determined.

6. The thin film stress measurement method according to claim 5, characterized in that: The determining, based on the second detection information of each second measurement point, the second offset of each second measurement point relative to the film surface comprises: The second offset of each second measuring point relative to the film surface is determined according to the preset corresponding relationship between the liquid level change value and the offset.

7. The thin film stress measurement method according to claim 1, characterized in that: Determining the second radius of curvature of the wafer after coating according to the position information of each second measuring point and the second offset corresponding to each second measuring point includes: According to the position information of each second measurement point and the second offset corresponding to each second measurement point, a preset fitting algorithm is used to perform fitting processing to obtain a second fitting circle corresponding to the thin film surface of the wafer after coating; The radius of the second fitting circle is determined as the second curvature radius of the wafer after coating.

8. The thin film stress measurement method according to claim 1, characterized in that: A plurality of first measuring points are arranged along the same diameter of the wafer surface of the wafer before coating, and a plurality of second measuring points are arranged along the same diameter of the thin film surface of the wafer after coating.

9. A thin film stress measuring device, characterized in that: include: A data acquisition unit, adapted to acquire position information of a plurality of first measurement points on the wafer surface of the wafer before coating; And, it is suitable for obtaining position information of a plurality of second measurement points on the thin film surface of the wafer after coating; A processing unit is adapted to obtain first detection information of each first measurement point on the wafer surface of the wafer before coating, and determine the first offset of each first measurement point relative to the wafer surface according to the first detection information of each first measurement point; wherein one first measurement point corresponds to one first offset; and, determine the first radius of curvature of the wafer before coating according to the position information of each first measurement point and the first offset corresponding to each first measurement point; and, obtain second detection information of each second measurement point on the thin film surface of the wafer after coating, and determine the second offset of each second measurement point relative to the thin film surface according to the second detection information of each second measurement point; wherein one second measurement point corresponds to one second offset; and, determine the second radius of curvature of the wafer after coating according to the position information of each second measurement point and the second offset corresponding to each second measurement point; and, determine the stress of the wafer after coating according to the first radius of curvature and the second radius of curvature.

10. A film stress measurement system, characterized in that: include: processors and detectors; a processor adapted to generate a first motion control signal and a second motion control signal; and, according to the first detection information provided by the detector, determining the first offset of each first measurement point on the wafer surface of the wafer before coating relative to the wafer surface; wherein one first measurement point corresponds to one first offset; and, according to the second detection information provided by the detector, determining the second offset of each second measurement point on the thin film surface of the wafer after coating relative to the thin film surface; wherein one second measurement point corresponds to one second offset; and, according to the position information of each first measurement point on the wafer surface of the wafer before coating and the first offset corresponding to each first measurement point, determining the first radius of curvature of the wafer before coating, and according to the position information of each second measurement point on the thin film surface of the wafer after coating and the second offset corresponding to each second measurement point, determining the second radius of curvature of the wafer after coating; and, according to the first radius of curvature and the second radius of curvature, determining the stress of the wafer after coating; The detector is adapted to respond to the first motion control signal, move along the wafer surface of the wafer before coating with a preset first step length, and contact multiple first measurement points on the wafer surface of the wafer before coating to obtain first detection information of each first measurement point, and output the first detection information to the processor; and is adapted to respond to the second motion control signal, move along the wafer surface after coating with a preset second step length, and contact multiple second measurement points on the thin film surface of the wafer after coating to obtain second detection information of each second measurement point, and output the second detection information to the processor.

11. The thin film stress measurement system according to claim 10, characterized in that: The first detection information of the first measuring point includes a first liquid level change value corresponding to the first measuring point, where the first liquid level value is used to characterize the warping degree of the first measuring point relative to the wafer surface; The detector is adapted to generate a first detection signal including a first pressure value before each first measurement point on the wafer surface that is not in contact with the wafer before coating; and, generating a second detection signal including a second pressure value when contacting each first measurement point on the wafer surface of the wafer before coating; The processor is adapted to determine the pressure difference between the first pressure value and the second pressure value according to the first detection signal and the second detection signal corresponding to each first measurement point on the wafer surface of the wafer before coating; And, according to the pressure difference between the first pressure value and the second pressure value, the first liquid level change value corresponding to each first measuring point on the wafer surface of the wafer before coating is determined.

12. The thin film stress measurement system according to claim 10, characterized in that: The second detection information of the second measuring point includes a second liquid level change value corresponding to the second measuring point, and the second liquid level value is used to characterize the warping degree of the second measuring point relative to the film surface; The detector is adapted to generate a third detection signal including a third pressure value before each second measurement point on the thin film surface of the wafer after the coating is not contacted; and, generating a fourth detection signal including a fourth pressure value when contacting each second measurement point on the thin film surface of the wafer after coating; The processor is suitable for determining the pressure difference between the third pressure value and the fourth pressure value based on the third detection signal and the fourth detection signal corresponding to each second measurement point on the thin film surface of the wafer after coating; and determining the second liquid level change value corresponding to each second measurement point on the thin film surface of the wafer after coating based on the pressure difference between the third pressure value and the fourth pressure value.

13. The thin film stress measurement system according to claim 10, characterized in that: There are multiple detectors; before the wafer is coated, the position of each detector corresponds to the position of each measurement point on the wafer surface before coating; after the wafer is coated, the position of each detector corresponds to the position of each measurement point on the wafer surface after coating.

14. The thin film stress measurement system according to claim 10 or 13, characterized in that: The detector comprises: a crossbar electrically connected to the processor; A hydraulic cylinder disposed on the crossbar, wherein the hydraulic cylinder has a liquid; A sensor electrically connected to the processor and disposed in the hydraulic cylinder to detect changes in the liquid level in the hydraulic cylinder; A probe slidably cooperates with the hydraulic cylinder, and when the probe contacts each first measuring point on the wafer surface of the wafer before coating, the liquid level in the hydraulic cylinder changes; and when the probe contacts each second measuring point on the thin film surface of the wafer after coating, the liquid level in the hydraulic cylinder changes.

15. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is run, the steps of the thin film stress measurement method according to any one of claims 1 to 8 are executed.

16. A computer program product, characterized in that The method comprises computer instructions, which, when executed by a processor, implement the steps of the thin film stress measurement method according to any one of claims 1 to 8.

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