A fused wafer bump three-dimensional topography measurement system

Abstract

The present disclosure relates to a fused wafer bump three-dimensional topography measurement system, comprising: an image acquisition module, a calculation module; the image acquisition module comprises a line scanning image acquisition module and a phase shift image acquisition module; the line scanning image acquisition module comprises a line scanning projection unit and a plurality of line scanning imaging units, the line scanning projection unit is used for projecting a first light beam onto a wafer bump; the line scanning imaging unit is used for scanning the part of the wafer bump projected by the first light beam to obtain a first image; the phase shift image acquisition module comprises a pattern projection unit and a plurality of phase shift imaging units; the pattern projection unit is used for projecting a stripe pattern onto the wafer bump through a second light beam; the phase shift imaging unit is used for acquiring a second image of the wafer bump containing the projected stripe pattern from multiple angles; the calculation module is used for determining the topography data of the wafer bump based on the plurality of first images and the plurality of second images, which can improve the accuracy of the entire wafer bump topography data.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of measurement, in particular to a fused wafer bump three-dimensional topography measurement system. BACKGROUND

[0002] Wafer bumps are used for input / output (I / O) connections, and the topography data characterizing the topography profile is a key element to ensure reliable connections. Therefore, the detection of wafer bumps has become an extremely important quality control link in chip manufacturing.

[0003] With the continuous progress of advanced packaging technology, wafer bumps are increasingly miniaturized in the height direction, and it is facing increasingly severe challenges to achieve high-speed and high-precision detection required for production.

[0004] Currently, two methods, line scanning method and phase shift method, are mainly used to determine the topography data of wafer bumps. However, each of the two methods has advantages and disadvantages. Although the line scanning method can obtain high single-point measurement accuracy, it is difficult to obtain accurate three-dimensional topography profile around the vertex of the wafer bump, which is also one of the key factors for process control. In contrast, the phase shift method can obtain the entire three-dimensional topography profile of the top region of the wafer bump, but the local measurement accuracy is difficult to guarantee.

[0005] Therefore, it has been difficult to accurately obtain the overall three-dimensional topography data of the wafer bump. SUMMARY

[0006] In view of this, the present disclosure proposes a fused wafer bump three-dimensional topography measurement system. The system comprises:

[0007] an image acquisition module, a calculation module;

[0008] The image acquisition module comprises a line scanning image acquisition module and a phase shift image acquisition module.

[0009] The line scanning image acquisition module comprises at least one line scanning projection unit and a plurality of line scanning imaging units,

[0010] The line scanning projection unit is configured to project a first light beam onto the wafer bump.

[0011] The line scanning imaging unit is configured to scan the part of the wafer bump on which the first light beam is projected to obtain a first image.

[0012] The phase shift image acquisition module comprises at least one pattern projection unit and a plurality of phase shift imaging units.

[0013] The pattern projection unit is configured to project a stripe pattern onto the wafer bump through a second light beam.

[0014] the phase shift imaging unit is configured to acquire a second image containing the wafer bump on which the fringe pattern is projected from multiple angles;

[0015] the calculation module is configured to determine topography data of the wafer bump based on the multiple first images and the multiple second images.

[0016] In a possible implementation, the line scanning projection unit comprises at least one light source and a first lens arranged between the light source and the wafer bump.

[0017] the line scanning imaging unit comprises at least one first camera and a second lens arranged between the first camera and the wafer bump.

[0018] the light source is configured to emit the first light beam, the first light beam is emitted from the line scanning projection unit through the first lens, reaches the wafer bump, is refracted at a first refraction angle, reaches the second lens, and reaches the first camera through the second lens.

[0019] the pattern projection unit comprises a projection device and a third lens arranged between the projection device and the wafer bump.

[0020] the phase shift imaging unit comprises a second camera and a fourth lens arranged between the second camera and the wafer bump.

[0021] the projection device is configured to emit the second light beam, the second light beam is emitted from the pattern projection unit through the third lens, and the fringe pattern is projected onto the wafer bump through the second light beam, the second light beam is refracted at a second refraction angle and reaches the fourth lens, and the fourth lens reaches the second camera.

[0022] In a possible implementation, the light source comprises a non-coherent light source.

[0023] the line scanning projection unit comprises a first non-coherent light source, a second non-coherent light source, and a first beam splitter.

[0024] the first non-coherent light source emits a first non-coherent light beam, the second non-coherent light source emits a second non-coherent light beam, and the first beam splitter causes the first non-coherent light beam and the second non-coherent light beam to coincide outside the line scanning projection unit.

[0025] In a possible implementation, the line scanning imaging unit comprises two first cameras and a second beam splitter, and the second beam splitter causes the light paths of the two first cameras to coincide outside the line scanning imaging unit.

[0026] In a possible implementation, the pattern projection unit is configured to make the second light beam perpendicular to a plane in which the wafer bump is located.

[0027] In a possible implementation, the pattern projection unit comprises a projection device, a third camera, a third beam splitter, a sixth lens arranged between the third beam splitter and the wafer bump, and a fifth lens arranged between the third camera and the third beam splitter.

[0028] The third beam splitter is configured to make the light paths of the projection device and the third camera coincide outside the pattern projection unit and perpendicular to a plane in which the wafer bump is located.

[0029] The pattern projection unit is further configured to acquire the second image.

[0030] In a possible implementation, the system comprises a control module.

[0031] The control module is configured to control the image acquisition module to scan the wafer bump row by row.

[0032] The control module is configured to control the line scanning image acquisition module to acquire the first image during movement of the image acquisition module.

[0033] The control module is configured to control the image acquisition module to stop moving and control the phase shift image acquisition module to acquire the second image when the image acquisition module moves to the end of each row.

[0034] In a possible implementation, the calculation module is further configured to:

[0035] Determine, based on a plurality of the first images, first heights of each solid point on the surface of the wafer bump.

[0036] Determine, based on a plurality of the second images, second heights of the each solid point.

[0037] For a single solid point, first fuse a plurality of the first heights corresponding to the single solid point to obtain a first basic height of the single solid point, and second fuse a plurality of the second heights corresponding to the single solid point to obtain a second basic height of the single solid point.

[0038] Third fuse the first basic height and the second basic height of the each solid point to obtain a target height of the each solid point, and the target height is used to determine the topographic data.

[0039] In a possible implementation, the calculation module is further configured to:

[0040] determine, based on the second image, a wrapped phase corresponding to each of pixels in the second image;

[0041] perform, for each of the wrapped phases, a first unwrapping process to obtain a second initial height of the first physical point corresponding to the wrapped phase;

[0042] determine a quality indicator representing a quality of the wrapped phase;

[0043] in a case where the quality indicator is greater than a quality threshold, take the second initial height of the first physical point corresponding to the wrapped phase as a second height of the first physical point;

[0044] in a case where the quality indicator is not greater than the quality threshold, determine a difference between the second initial height and a first base height of the first physical point;

[0045] in a case where the difference is less than a first threshold, perform a fourth fusion on the second initial height and the first base height of the first physical point to obtain the second height of the first physical point;

[0046] in a case where the difference is not less than the first threshold, determine a peripheral pixel corresponding to the pixel corresponding to the wrapped phase;

[0047] perform, based on a first wrapped phase corresponding to each of the peripheral pixels, a second unwrapping process on the wrapped phase to obtain the second height of the first physical point.

[0048] In a possible implementation, the computing module is further configured to:

[0049] determine a spatial indicator according to a position of the pixel corresponding to the wrapped phase in a stripe period of the stripe pattern;

[0050] determine a gray scale of the pixel corresponding to the wrapped phase;

[0051] determine a modulation indicator representing the pixel corresponding to the wrapped phase based on the gray scale;

[0052] determine the quality indicator according to the spatial indicator and the modulation indicator.

[0053] The line scanning method and the phase shift method can be fused by using the fused wafer bump three-dimensional topography measurement system in the present disclosure. In one measurement process, a first image can be obtained by the line scanning method and a second image can be obtained by the phase shift method, thereby improving the measurement efficiency. In addition, the line scanning image acquisition module and the phase shift image acquisition module are in the same system and have a fixed relative position, so that the data obtained by the two methods can be more accurately fused in the process of determining the topography data, thereby improving the accuracy of the topography data. Moreover, the topography data determined by the first image and the second image can improve the accuracy of the local topography data on the premise of obtaining the entire three-dimensional topography profile of the wafer bump, thereby improving the accuracy of the entire wafer bump topography data.

[0054] Other features and aspects of the present disclosure will become apparent from the following detailed description of exemplary embodiments with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0055] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the present disclosure and serve to explain the principles of the present disclosure.

[0056] Figure 1 A structure schematic diagram of a fused wafer bump three-dimensional topography measurement system provided by an embodiment of the present disclosure.

[0057] Figure 2 A structure schematic diagram of a line scanning image acquisition module provided by an embodiment of the present disclosure.

[0058] Figure 3 A structure schematic diagram of a phase shift image acquisition module provided by an embodiment of the present disclosure.

[0059] Figure 4 A structure schematic diagram of a line scanning projection unit provided by an embodiment of the present disclosure.

[0060] Figure 5 A structure schematic diagram of a line scanning imaging unit provided by an embodiment of the present disclosure.

[0061] Figure 6 A structure schematic diagram of a pattern projection unit provided by an embodiment of the present disclosure.

[0062] Figure 7 A flowchart of a wafer bump three-dimensional topography measurement method provided by an embodiment of the present disclosure. DETAILED DESCRIPTION

[0063] Various exemplary embodiments, features, and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. The same reference numbers in different drawings represent the same or similar elements / function. Although various aspects of embodiments are illustrated in the drawings, the drawings are not necessarily drawn to scale unless specifically noted.

[0064] As used herein, the terms "comprise", "comprising", "have", "having", "include", "including", "contain", "containing", "provide", "providing", or variants thereof are open-ended, and include one or more stated features, integers, elements, steps, components, or functions but do not preclude the presence or addition of one or more other features, integers, elements, steps, components, functions, or groups thereof.

[0065] When an element is referred to as being "connected", "coupled", "responsive", or "correlated" to another element, it can be directly connected, coupled, responsive, or correlated to the other element, or intervening elements can be present.

[0066] Although the terms first, second, third, etc. can be used herein to describe various elements / operations, these elements / operations should not be limited by these terms. These terms are only used to distinguish one element / operation from another element / operation. Thus, a first element / operation in some embodiments could be termed a second element / operation in other embodiments without departing from the teachings of the present inventive concept.

[0067] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations.

[0068] In addition, for the purpose of convenience and brevity, detailed descriptions of well-known devices, methods, procedures, components, and circuits are not described in detail herein. It will be appreciated that the present disclosure can be practiced with the elements recited in the detailed description without resorting to the details not specifically drawn in the figures.

[0069] Figure 1 A structural schematic diagram of a fused wafer bump three-dimensional topography measurement system is provided for the embodiments of the present disclosure. As shown in Figure 1As shown, the system comprises an image acquisition module and a calculation module. The image acquisition module comprises a line scanning image acquisition module and a phase shift image acquisition module. The line scanning image acquisition module comprises at least one line scanning projection unit and a plurality of line scanning imaging units. The line scanning projection unit is configured to project a first light beam onto a wafer bump. The line scanning imaging unit is configured to scan a portion of the wafer bump that is projected by the first light beam to obtain a first image. The phase shift image acquisition module comprises at least one pattern projection unit and a plurality of phase shift imaging units. The pattern projection unit is configured to project a fringe pattern onto the wafer bump through a second light beam. The phase shift imaging unit is configured to acquire a second image containing the wafer bump projected by the fringe pattern from multiple angles. The calculation module is configured to determine topographic data of the wafer bump based on the plurality of first images and the plurality of second images.

[0070] In the embodiments of the present disclosure, the line scanning image acquisition module can comprise one line scanning projection unit and a plurality of line scanning imaging units. In another example, the line scanning image acquisition module can comprise a plurality of line scanning projection units and a plurality of line scanning imaging units. In this case, a single line scanning projection unit can correspond to a single line scanning imaging unit one by one, or a single line scanning projection unit can correspond to a plurality of line scanning imaging units. Each line scanning projection unit and the corresponding single line scanning imaging unit can form a first combination. Each first combination can acquire a first image of the wafer bump at at least one angle.

[0071] The first light beam can be a coherent light beam or a non-coherent light beam. The first light beam can be a first fused light beam obtained by fusing two non-coherent light beams. The coherent light beam can be a laser beam. The non-coherent light beam can be a white light beam.

[0072] In a measurement process for a wafer bump, the setting positions of the line scanning projection unit and the corresponding line scanning imaging unit can be fixed, so that the line scanning projection unit can project the first light beam onto the wafer bump, and the line scanning imaging unit corresponding to the line scanning projection unit can image the portion of the wafer bump projected by the first light beam to obtain a first image. The first image can contain a partial region of the wafer bump, and can also contain a partial region of the background scene of the wafer bump.

[0073] In the embodiments of the present disclosure, the phase shift image acquisition module can include one pattern projection unit and multiple phase shift imaging units. In another example, the phase shift image acquisition module can include multiple pattern projection units and multiple phase shift imaging units. In this case, one pattern projection unit can correspond to one phase shift imaging unit, or one pattern projection unit can correspond to multiple phase shift imaging units. Each pattern projection unit and the corresponding phase shift imaging unit can form a second combination. Each second combination can acquire a second image of the wafer bump at at least one angle.

[0074] The pattern projection unit can emit a second light beam to project a fringe pattern on the wafer bump through the second light beam.

[0075] In the measurement process of the wafer bump, the setting positions of the pattern projection unit and the corresponding phase shift imaging unit can be fixed, so that the pattern projection unit can project the second light beam on the wafer bump, and the phase shift imaging unit corresponding to the pattern projection unit can image the wafer bump with the projected fringe pattern and the background scene of the wafer bump to obtain a second image. The second image can include the entire wafer bump and the background scene of the wafer bump.

[0076] In the entire measurement process, the line scan image acquisition module can obtain multiple first images at multiple angles. The multiple first images corresponding to each angle can represent the wafer bump at the angle. In the entire measurement process, the phase shift image acquisition module can obtain multiple second images at multiple angles. The calculation module can determine the first height of each entity point on the wafer bump based on the first image. The calculation module can determine the second height of each entity point on the wafer bump based on the second image. The process of determining the first height and the second height is not the focus of the present disclosure, and the first height and the second height can be obtained by using the method (line scan method, phase shift method) in the related art. In the embodiments of the present disclosure, the first height and the second height corresponding to each entity point on the wafer bump can be fused to obtain the target height of each entity point. The spacing of the entity points can be pre-set, and the three-dimensional topography data of the wafer bump can be determined by combining the target height. The fusion method of the first height and the second height corresponding to the entity points is not limited in the embodiments of the present disclosure.

[0077] The fused wafer bump three-dimensional topography measurement system in the present disclosure can fuse the line scanning method and the phase shift method. In one measurement process, a first image can be obtained by the line scanning method and a second image can be obtained by the phase shift method, thereby improving the measurement efficiency. In addition, the line scanning image acquisition module and the phase shift image acquisition module are in the same system and have a fixed relative position, so that the data obtained by the two methods can be more accurately fused in the process of determining the topography data, thereby improving the accuracy of the topography data. Moreover, the topography data determined by the first image and the second image can improve the accuracy of the local topography data on the premise of obtaining the entire three-dimensional topography profile of the wafer bump, thereby improving the accuracy of the entire wafer bump topography data.

[0078] In a possible implementation, the line scanning projection unit comprises at least one light source and a first lens arranged between the light source and the wafer bump; the line scanning imaging unit comprises at least one first camera and a second lens arranged between the first camera and the wafer bump; the light source is configured to emit the first light beam, the first light beam is emitted from the line scanning projection unit through the first lens, reaches the wafer bump, and is refracted at a first refraction angle to reach the second lens and then reaches the first camera through the second lens; the pattern projection unit comprises a projection device and a third lens arranged between the projection device and the wafer bump; the phase shift imaging unit comprises a second camera and a fourth lens arranged between the second camera and the wafer bump; the projection device is configured to emit the second light beam, the second light beam is emitted from the pattern projection unit through the third lens, and the second light beam projects the fringe pattern to the wafer bump, the second light beam is refracted at a second refraction angle and reaches the fourth lens, and then reaches the second camera through the fourth lens.

[0079] Figure 2 A structural schematic diagram of the line scanning image acquisition module provided in the embodiments of the present disclosure is shown.

[0080] In the embodiments of the present disclosure, the line scanning image acquisition module can comprise a plurality of line scanning projection units 11 and a plurality of line scanning imaging units 10. Each line scanning projection unit 11 can comprise at least one light source 110, and each light source 110 can be provided with a first lens 111 corresponding thereto, and the first lens 111 can be arranged between the light source 110 and the wafer bump.

[0081] The single line scanning imaging unit 10 can include at least one first camera 100, each of which can correspond to a second lens 102 arranged between the first camera 100 and the wafer bump. In one example, a Scheimpflug angle adjusting device 101 can be arranged between the first camera 100 and the second lens 102 to increase the amount of information of the first image, so that the first image can accurately represent the part of the wafer bump that is projected by the first light beam.

[0082] Figure 3 A structural diagram of a phase shift image acquisition module provided by an embodiment of the present disclosure is provided.

[0083] In an embodiment of the present disclosure, the phase shift image acquisition module can include a plurality of pattern projection units 33 and a plurality of phase shift imaging units 30. A single pattern projection unit 33 can include a projection device 330. And a third lens 331 can be arranged between the projection device 330 and the wafer bump. Wherein the projection device 330 can be a Ronchi grating or a sinusoidal grating combined with a piezoelectric ceramic to realize phase shift projection. Or the projection device can use an optical machine to realize phase shift projection by pattern switching. The optical machine can include one or more of the following: a digital micromirror element optical machine, an off-axis optical projection system optical machine, an off-axis optical projection system, etc.

[0084] A single phase shift imaging unit 30 can include a second camera 300. And a fourth lens 302 can be arranged between the second camera 300 and the wafer bump. In one example, a Scheimpflug angle adjusting device 301 can be arranged between the second camera 300 and the fourth lens 302 to increase the amount of information of the second image, so that the second image can accurately represent the wafer bump as a whole.

[0085] In an embodiment of the present disclosure, the positions of the line scanning projection unit and the line scanning imaging unit are preset so that the first light beam can be refracted on the wafer bump according to a first refraction angle. In this way, the first light beam can reach the second lens, and the first image can accurately represent the part of the wafer bump that is projected by the first light beam. And the positions of the pattern projection unit and the phase shift imaging unit are preset so that the fringe pattern can be projected onto the wafer bump, and the second light beam can be refracted according to a second refraction angle. In this way, the second light beam can reach the fourth lens, and the second image can accurately represent the wafer bump as a whole.

[0086] In addition, the first lens 111, the second lens 102, the third lens 331, and the fourth lens 302 can be telecentric lenses, which increase the clarity of the first image and the second image, and reduce distortion.

[0087] The fused wafer bump three-dimensional topography measurement system in the embodiment of the present disclosure can obtain first images and second images of multiple angles in one measurement process, thereby improving the efficiency of determining the topography data of the wafer bump. Moreover, the negative influence of shadow blocking on the measurement result can be reduced, and the distortion is reduced and the measurement accuracy is improved.

[0088] In a possible implementation, the light source includes a non-coherent light source; the line scanning projection unit includes a first non-coherent light source, a second non-coherent light source, and a first beam splitter; the first non-coherent light source emits a first non-coherent light beam, the second non-coherent light source emits a second non-coherent light beam, and the first beam splitter causes the first non-coherent light beam and the second non-coherent light beam to coincide outside the line scanning projection unit.

[0089] Figure 4 A structural schematic diagram of a line scanning projection unit is provided for the embodiment of the present disclosure.

[0090] In the embodiment of the present disclosure, the line scanning projection unit 11 can include two non-coherent light sources, namely a first non-coherent light source 110a and a second non-coherent light source 110b. The line scanning projection unit 11 further includes a first beam splitter 112. The non-coherent light beams emitted by the first non-coherent light source 110a and the second non-coherent light source 110b respectively coincide in light path after passing through the first beam splitter 112, forming a first fused light beam. In the embodiment of the present disclosure, the first fused light beam can be used as the first light beam. The light beams provided by the first non-coherent light source 110a and the second non-coherent light source 110b can be white, purple, blue, green, red, etc. Moreover, the wavelengths of the light beams provided by the first non-coherent light source and the second non-coherent light source are different.

[0091] The line scanning projection unit in the embodiment of the present disclosure can perform line scanning based on double-wavelength differential non-coherent light. In this way, a long and bright projection line can be obtained, and the precision loss of non-coherent light can be reduced. The accuracy can also be maintained in the case of using a non-coherent light source.

[0092] In a possible implementation, the line scanning imaging unit includes two first cameras and a second beam splitter, and the second beam splitter causes the light paths of the two first cameras to coincide outside the line scanning imaging unit.

[0093] Figure 5 A structural schematic diagram of a line scanning imaging unit is provided for the embodiment of the present disclosure.

[0094] In the embodiments of the present disclosure, the line scanning imaging unit 10 includes two first cameras, i.e., a first camera 100a and a first camera 100b. The two first cameras can be industrial black-and-white cameras, which do not need to perform interpolation processing, thereby improving the accuracy of determining the height of the solid point on the wafer bump through the first image. The line scanning imaging unit 10 further includes a second beam splitter 103. The first light beam passes through the second beam splitter 103 and is split into two first light beams, so that the first camera 100a and the first camera 100b can both receive the first light beam.

[0095] In this way, the line scanning imaging unit in the embodiments of the present disclosure can break through the frame rate limit of a single first camera. The two first cameras can alternately work, thereby improving the first image acquisition efficiency.

[0096] In a possible implementation, the pattern projection unit is configured to make the second light beam perpendicular to a plane in which the wafer bump is located.

[0097] The pattern projection unit can emit a second light beam. The pattern projection unit is configured to make the second light beam perpendicular to a plane in which the wafer bump is located, and project a stripe pattern on the wafer bump in a perspective projection manner.

[0098] In this way, the phase shift image acquisition module only needs to set one pattern projection unit, and can complete the synchronous image acquisition of the multi-angle camera, thereby improving the second image acquisition efficiency.

[0099] In a possible implementation, the line scanning projection unit is configured to make the first light beam perpendicular to a surface in which the wafer bump is located.

[0100] The line scanning projection unit can emit a first light beam. The line scanning projection unit is configured to make the first light beam perpendicular to a plane in which the wafer bump is located, and make the first light beam perpendicular to the wafer bump.

[0101] In this way, the line scanning image acquisition module only needs to set one line scanning projection unit, and can complete the synchronous image acquisition of the multi-angle camera, thereby improving the first image acquisition efficiency.

[0102] In a possible implementation, the pattern projection unit includes a projection device, a third camera, a third beam splitter, a sixth lens arranged between the third beam splitter and the wafer bump, and a fifth lens arranged between the third camera and the third beam splitter. The third beam splitter is configured to make the light paths of the projection device and the third camera respectively coincide outside the pattern projection unit and perpendicular to a plane in which the wafer bump is located. The pattern projection unit is further configured to acquire the second image.

[0103] Figure 6 A structural schematic diagram of a pattern projection unit provided in the embodiments of the present disclosure is shown.

[0104] In the embodiments of the present disclosure, the pattern projection unit 33 can project the fringe pattern onto the wafer bump in a front projection manner; and the pattern projection unit 33 can also acquire the second image directly above the wafer bump. The pattern projection unit 33 comprises a third camera 332, a projection device 330, and a third beam splitter 334. Further comprising a fifth lens 333 arranged between the third camera 332 and the third beam splitter 334, and a sixth lens 335 arranged between the third beam splitter 334 and the wafer bump. The fifth lens 333 and the sixth lens 335 can be telecentric lenses. Due to the arrangement of the third beam splitter 334, the light path of the second light beam projected by the projection device 330 is coincident with the light path of the third camera 332 between the pattern projection unit 33 and the wafer bump.

[0105] In this way, the pattern projection unit can not only project the fringe pattern onto the wafer bump in a front projection manner, but also acquire the second image at the angle directly above the wafer bump, thereby better reducing the probability of shadow blocking and improving the ability to suppress specular reflection, and improving the accuracy of the second image in displaying the wafer bump.

[0106] In a possible implementation, the system comprises a control module; the control module is configured to control the image acquisition module to scan the wafer bump row by row; the control module is configured to control the line-scan image acquisition module to acquire the first image during movement of the image acquisition module; and the control module is configured to control the image acquisition module to stop moving and control the phase-shift image acquisition module to acquire the second image when the image acquisition module moves to the end of each row.

[0107] The control module can control the line-scan image acquisition module and the phase-shift image acquisition module in the image acquisition module to work cooperatively to acquire the first image and the second image.

[0108] The control module can control the image acquisition module to move row by row, and the image acquisition module can scan the wafer bump, i.e., the line-scan image acquisition module in the image acquisition module can acquire the first image during movement.

[0109] The motion trajectory of the image acquisition module can be pre-set, and each row has a starting position and an ending position. The end of each row can be the ending position of each row. When the image acquisition module reaches the end of each row, the control module can control the image acquisition module to stop moving, and control the phase-shift image acquisition module to acquire the second image for the wafer bump.

[0110] And, different magnifications can be set for each row to adjust the field of view of each row. In the column direction of the movement path, the field of view of each row can comprehensively cover the corresponding column on the wafer bump. In this way, a suitable field of view can be set for each row according to actual needs, and the increase or decrease of the number of scanning rows is adjusted, so that the scanning precision or scanning efficiency is improved.

[0111] In the embodiments of the present disclosure, the control module can cause the image acquisition module to alternately acquire the first image and the second image, thereby improving the acquisition efficiency.

[0112] In a possible implementation, the calculation module is further configured to: determine, based on the plurality of first images, first heights of each entity point on the surface of the wafer bump; determine, based on the plurality of second images, second heights of the entity points; for a single entity point, perform first fusion on a plurality of first heights corresponding to the single entity point to obtain a first basic height of the single entity point, and perform second fusion on a plurality of second heights corresponding to the single entity point to obtain a second basic height of the single entity point; and perform third fusion on the first basic heights and the second basic heights of the entity points to obtain target heights of the entity points, wherein the target heights are used to determine the topographic data.

[0113] As described above, the line scanning image acquisition module can acquire the first image at different angles. For a single angle, a plurality of first images can be obtained. The plurality of first images obtained at a single angle can collectively exhibit the wafer bump. Using the line scanning method, the first heights of the entity points on the wafer bump can be determined based on the first image corresponding to the single angle. For example, in the case of a coherent light source, the scanning center line can be extracted from the first image, and the first height of the entity point corresponding to the first image can be determined using the triangulation method. For another example, if only the height of the vertex of the wafer bump needs to be measured, even if the light source is a non-coherent light source, the first height of the vertex corresponding to the first image can be determined by the projection method, so that the error caused by the non-coherent light projection line being thicker than the coherent light projection line can be reduced, and the accuracy of the first height of the vertex can be improved.

[0114] For a single entity point, a plurality of first heights of the entity point can be determined based on the first images corresponding to a plurality of angles respectively. In this way, each entity point can correspond to a plurality of first heights. The plurality of first heights corresponding to each entity point can be first fused to obtain a first basic height corresponding to each entity point. The present disclosure does not limit the specific method of the first fusion. For example, the first fusion can be to determine the average value or the median of the plurality of first heights. Or a weight can be set for each angle, and the first fusion can be to perform weighted averaging on the first heights by using the weight.

[0115] At each time the image acquisition module stops moving, the phase shift image acquisition module can acquire a plurality of second images of the wafer bump from a plurality of angles. Using the phase shift method, based on a single second image, the second height of each entity point of the wafer bump can be determined. In this way, each entity point can correspond to a plurality of second heights. The plurality of second heights corresponding to each entity point can be second fused to obtain a second basic height corresponding to each entity point. The specific method of the second fusion is not limited in the embodiments of the present disclosure. For example: the second fusion can be to determine the average value or the median of the plurality of second heights. Or a weight can be set for each angle, and the second fusion can use the weight to perform a weighted average of the second height.

[0116] A single entity point can correspond to two heights determined respectively using the line scanning method and using the phase shift method, i.e., the first basic height and the second basic height. The first basic height can be assigned a first weight, and the second basic height can be assigned a second weight. Since the accuracy of the line scanning method is better than that of the phase shift method, the first weight can be greater than the second weight. The third fusion can be to use the first weight to weight the first basic height and use the second weight to weight the second basic height. And determine the average value of the weighted first basic height and the weighted second basic height, and take the average value as the target height of the entity point. Based on the related art, the target height can be used to determine the topography data of the wafer bump.

[0117] The calculation unit in the embodiments of the present disclosure can improve the accuracy of the height of each entity point of the wafer bump determined using the line scanning method through the first fusion; improve the accuracy of the height of each entity point of the wafer bump determined using the phase shift method through the second fusion; and fuse the heights of each entity point determined by the line scanning method and the phase shift method through the third fusion. In this way, the target height reflects the respective advantages of the line scanning method and the phase shift method. Both the target height of each entity point on the overall profile of the wafer bump and the accuracy and precision of the target height are improved.

[0118] In a possible implementation, the computing module is further configured to: determine, based on the second image, a respective wrapped phase of each pixel in the second image; perform first unwrapping processing on each wrapped phase to obtain a second initial height of each entity point; determine a quality index representing a quality of the wrapped phase; in a case where the quality index is greater than a quality threshold, take the second initial height of the first entity point corresponding to the wrapped phase as a second height of the first entity point; in a case where the quality index is not greater than the quality threshold, determine a difference between the second initial height of the first entity point and the first base height; in a case where the difference is less than a first threshold, perform fourth fusion on the second initial height of the first entity point and the first base height to obtain the second height of the first entity point; and in a case where the difference is not less than the first threshold, determine a peripheral pixel corresponding to the pixel corresponding to the wrapped phase, perform second unwrapping processing on the wrapped phase based on a first wrapped phase corresponding to each peripheral pixel to obtain the second height of the first entity point.

[0119] In the embodiments of the present disclosure, a first mapping relationship between a first coordinate system of the first image and a world coordinate system can be established in advance, and a second mapping relationship between a second coordinate system of the second image and the world coordinate system can be established. The second coordinate system can be used to determine the first entity point on the wafer bump in the real world corresponding to the pixel in the second image. In this way, the first entity point corresponding to the wrapped phase corresponding to the pixel can be determined. Then, the second initial height determined according to the wrapped phase can be taken as the initial height of the first entity point. Using the first mapping relationship and the second mapping relationship, the second initial height corresponding to the first entity point and the first base height can be determined, that is, the second initial height and the first base height of the same first entity point are corresponded.

[0120] In the embodiments of the present disclosure, the wrapped phase corresponding to each pixel in the second image can be determined based on the second image by using a related technology, for example, a multi-frequency phase shift method. The first unwrapping processing can be a processing method based on a time unwrapping algorithm. After the first unwrapping processing, the second initial height of each entity point can be obtained. The time unwrapping algorithm based on time can save the time for determining the second initial height. Then, the quality of each wrapped phase can be determined to obtain the quality index.

[0121] Exemplarily, a quality judgment model can be trained in advance. The second image and each wrapped phase can be input into the quality judgment model to obtain the quality index of each wrapped phase.

[0122] Exemplarily, a plurality of phase threshold ranges can be set by experiments, each phase threshold range corresponds to a quality index, and it is determined in which phase threshold range each wrapped phase falls, and then the corresponding quality index is obtained.

[0123] The above is only an example, and the embodiments of the present disclosure do not limit the method for determining the quality index.

[0124] If the quality index is greater than the quality threshold, it indicates that the second initial height is reliable and can be used as the second height of the first entity point.

[0125] If the quality index is not greater than the quality threshold, it is necessary to determine the difference between the second initial height corresponding to the first entity point and the first base height. Generally, the accuracy of the line scanning method is better than that of the phase shift method. Therefore, based on the two methods, the height of the same entity point determined by the two methods can be obtained, that is, two heights are obtained, and the difference between the two heights is obtained. Using the difference, it can be determined whether the second initial height is available.

[0126] If the difference is less than the first threshold, it indicates that the second initial height is available. Then the fourth fusion of the second initial height and the first base height can be performed. The fourth fusion can be a weighted average processing of the second initial height and the first base height to obtain the second height of the first entity point. The weight of the first base height is higher than the weight of the second initial height.

[0127] If the difference is not less than the first threshold, it indicates that the second initial height is inaccurate and unavailable. It is necessary to determine the second height according to the wrapped phase corresponding to the first entity point. The surrounding pixels of the pixel corresponding to the wrapped phase can be obtained, for example, the pixels adjacent to the pixel corresponding to the wrapped phase and representing the vertices of the wafer bump can be obtained. In order to facilitate description, the wrapped phase corresponding to the surrounding pixels is named as the first wrapped phase. The second unwrapping processing can be performed on each first wrapped phase. The second unwrapping processing can be a path-independent unwrapping algorithm, such as Goldstein unwrapping algorithm, Quality-Guided unwrapping algorithm, Least Squares unwrapping algorithm, Adaptive unwrapping algorithm, etc. In the scene where the calculation speed is required to be prioritized, the second unwrapping processing can also be a path-dependent algorithm. Not only can it improve the calculation efficiency. In this way, the second height can be determined.

[0128] In addition, increasing the sampling frequency of line scanning (reducing the scanning line spacing) can reduce the accumulated error in the unwrapping process and make up for the insufficient accuracy in the case of using incoherent light source, thereby improving the accuracy of unwrapping by reducing the approximation range.

[0129] The calculation module in the embodiments of the present disclosure considers the quality of the wrapped phase corresponding to the entity point and the reliability of the second initial height value corresponding to the entity point (the difference between the second initial height and the first base height) together, determines the second height in different cases using different methods, and improves the accuracy of the second height determined by the phase shift method.

[0130] In a possible implementation, the computing module is further configured to: determine a spatial index according to a position of the pixel corresponding to the wrapped phase in a period of the fringe pattern; determine a gray scale of the pixel corresponding to the wrapped phase; determine a modulation index index of the pixel corresponding to the wrapped phase based on the gray scale; and determine the quality index according to the spatial index and the modulation index index.

[0131] The phase may be lost or broken at the junction of two fringe periods, which may further cause period errors. The errors are more serious in multi-frequency projection than in single-frequency projection. Therefore, in the embodiments of the present disclosure, a spatial index can be determined based on a position of the pixel corresponding to the wrapped phase in a period of the fringe pattern. The closer the position is to the junction of two fringe periods, the smaller the value of the spatial index. Conversely, the farther the position is from the junction of two fringe periods, the larger the value of the spatial index. The spatial index can be weighted by setting corresponding coefficients for single-frequency projection and multi-frequency projection.

[0132] The modulation index index can include a contrast between the fringe pattern and the background, a variation amplitude of the luminance in the period, and the like. Therefore, the modulation index index can be determined according to the gray scale of the pixel corresponding to the wrapped phase. The higher the contrast between the fringe pattern and the background, the larger the value of the modulation index index. The larger the variation amplitude of the luminance in the period, the larger the value of the modulation index index. Conversely, the lower the contrast between the fringe pattern and the background, the smaller the value of the modulation index index. The smaller the variation amplitude of the luminance in the period, the smaller the value of the modulation index index.

[0133] The spatial index and the modulation index index can be weighted and summed to obtain the quality index. In order to more effectively screen out pixels with phase breaks that have a serious impact on height measurement, the weight corresponding to the spatial index can be greater than the weight corresponding to the modulation index index. The larger the value of the quality index, the better the quality of the wrapped phase, and the smaller the value of the quality index, the worse the quality of the wrapped phase.

[0134] In the embodiments of the present disclosure, the computing module can determine the spatial index and the modulation index index according to the position of the pixel corresponding to the wrapped phase in a period of the fringe pattern and the gray scale of the pixel, thereby improving the reliability of the quality index and the accuracy and reliability of the quality evaluation of the wrapped phase.

[0135] Figure 7 A flowchart of a wafer bump three-dimensional topography measurement method provided by the embodiments of the present disclosure is shown. For ease of understanding, the flowchart is divided into two parts: a line scanning part and a phase shift part. As shown in FIG. 1, the line scanning part includes the following steps. Figure 7As shown, a plurality of first images and a plurality of second images can be obtained. The line scanning imaging can be performed at a plurality of angles. A plurality of first images can be obtained at a single angle. Based on the first images, a plurality of first heights of each physical point on the wafer bump can be calculated. For each physical point, the corresponding plurality of first heights is first fused to obtain a first basic height of each physical point on the wafer bump.

[0136] A single second image can be an image obtained by phase shifting imaging at a single angle. Based on the single second image, a corresponding wrapped phase of each pixel in the second image can be calculated. Based on the first mapping relationship and the second mapping relationship, the second initial height and the first basic height of the same physical point are determined.

[0137] For each wrapped phase, a first unwrapping process is performed to obtain the second initial height of each physical point on the wafer bump. Moreover, it is determined whether the quality of each wrapped phase is greater than a quality threshold. In the case where the quality of the wrapped phase is greater than the quality threshold, the second initial height is taken as the second height. In the case where the quality of the wrapped phase is not greater than the quality threshold, the difference between the second initial height and the first basic height of the physical point corresponding to the wrapped phase is determined. It is determined whether the difference is less than a first threshold. In the case where the difference is less than the first threshold, the second initial height and the first basic height of the physical point corresponding to the wrapped phase are fourth fused to obtain the second height. In the case where the difference is not less than the first threshold, the surrounding pixels of the pixel corresponding to the wrapped phase are determined, for example, the surrounding pixels representing the vertices of the wafer bump. Based on the first wrapped phase of the surrounding pixels, a second unwrapping process is performed to obtain the second height.

[0138] The above three operations can obtain the second height, and one of them can be selected and executed according to the actual situation to obtain the second height. In this way, based on each second image, the second height of each physical point on the wafer bump can be obtained. Therefore, a plurality of second heights of each physical point on the wafer bump can be obtained. For each physical point, the corresponding plurality of second heights is second fused to obtain a second basic height of each physical point on the wafer bump.

[0139] Moreover, for each physical point, the corresponding first basic height and second basic height are third fused to obtain a target height of each physical point on the wafer bump. The target height can be used for the topography data of the wafer bump.

[0140] The computer program product of the second aspect can include a computer readable storage medium. The computer readable storage medium can include instructions. The instructions can include one or both of: instructions for causing a computer to enable a user equipment device to receive a configuration message from a base station, the configuration message comprising an indication of a set of one or more parameters for a first type of hybrid automatic repeat request process, the first type of hybrid automatic repeat request process being associated with a first type of data; and instructions for causing a computer to enable a user equipment device to receive a configuration message from a base station, the configuration message comprising an indication of a set of one or more parameters for a first type of hybrid automatic repeat request process, the first type of hybrid automatic repeat request process being associated with a first type of data.

[0141] Embodiments of the present disclosure have been described above, with the understanding that these embodiments are exemplary only, and are not restrictive, and are not limited to the disclosed embodiments. Many modifications and changes to this disclosure would be apparent to those of ordinary skill in the art. The scope of the technology disclosed is not to be limited by the specific illustrative embodiments presented above, but only by the claims that follow. The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting.

Claims

1. A fused wafer bump three-dimensional topography measurement system, characterized in that, The system includes: an image acquisition module and a calculation module; The image acquisition module includes: a line scan image acquisition module and a phase shift image acquisition module; The line scan image acquisition module includes: at least one line scan projection unit and multiple line scan imaging units. The line scan projection unit is used to project the first beam onto the wafer bumps; The line scan imaging unit is used to scan the portion of the wafer bump onto which the first beam is projected to obtain a first image; The phase shift image acquisition module includes: at least one pattern projection unit and multiple phase shift imaging units; The pattern projection unit is used to project a striped pattern onto the wafer bumps via a second light beam. The phase-shift imaging unit is used to acquire a second image from multiple angles containing wafer bumps to which the stripe pattern is projected. The calculation module is used to determine the morphology data of the wafer bumps based on multiple first images and multiple second images; The system includes a control module; The control module is used to control the image acquisition module to scan the wafer bumps line by line; The control module controls the line scan image acquisition module to acquire the first image during the movement of the image acquisition module; The control module, when the image acquisition module moves to the end of each row, controls the image acquisition module to stop moving and controls the phase-shifted image acquisition module to acquire the second image; The computing module is further used for: Based on multiple of the first images, the first height of each solid point on the surface of the wafer bump is determined; Based on multiple second images, determine the second height of each entity point; For a single entity point, the multiple first heights corresponding to the single entity point are firstly merged to obtain the first base height of the single entity point, and the multiple second heights corresponding to the single entity point are secondly merged to obtain the second base height of the single entity point; The first base height and the second base height of each entity point are fused together to obtain the target height of each entity point. The target height is used to determine the shape data. The computing module is further used for: Based on the second image, determine the wrapping phase corresponding to each pixel in the second image; For each of the wrapped phases, a first unwrapping process is performed to obtain the second initial height of each entity point; Determine the quality index that characterizes the quality of the packaged phase; If the quality index is greater than the quality threshold, the second initial height of the first entity point corresponding to the package phase is taken as the second height of the first entity point. If the quality index is not greater than the quality threshold, determine the difference between the second initial height and the first base height of the first entity point; If the difference is less than the first threshold, the second initial height and the first base height of the first entity point are fused in the fourth way to obtain the second height of the first entity point; If the difference is not less than a first threshold, the surrounding pixels that characterize the pixel corresponding to the wrapping phase are determined; Based on the first wrapping phase corresponding to each surrounding pixel, the wrapping phase is subjected to a second unwrapping process to obtain the second height of the first entity point.

2. The system according to claim 1, characterized in that, The line scan projection unit includes: at least one light source and a first lens disposed between the light source and the wafer bump; The line scan imaging unit includes: at least one first camera, and a second lens disposed between the first camera and the wafer bump; The light source is used to emit the first beam, which passes through the first lens from the line scan projection unit, reaches the wafer bump, is refracted at a first refraction angle, reaches the second lens, and then reaches the first camera. The pattern projection unit includes: a projection device and a third lens disposed between the projection device and the wafer bump; The phase-shift imaging unit includes: a second camera and a fourth lens disposed between the second camera and the wafer bump; The projection device is used to emit the second beam, which passes through the third lens and exits the pattern projection unit, projecting the stripe pattern onto the wafer bump. The second beam is refracted at a second refraction angle and reaches the fourth lens, then reaches the second camera.

3. The system according to claim 2, characterized in that, The light source includes an incoherent light source; The line scan projection unit includes: a first incoherent light source, a second incoherent light source, and a first beam splitter; The first incoherent light source emits a first incoherent light beam, the second incoherent light source emits a second incoherent light beam, and the first beam splitter causes the first incoherent light beam and the second incoherent light beam to overlap outside the line scan projection unit.

4. The system according to claim 2, characterized in that, The line scan imaging unit includes two first cameras and a second beam splitter, wherein the second beam splitter causes the optical paths of the two first cameras to overlap outside the line scan imaging unit.

5. The system according to claim 2, characterized in that, The pattern projection unit makes the second beam perpendicular to the plane where the wafer bump is located.

6. The system according to claim 5, characterized in that, The pattern projection unit includes: a projection device, a third camera, a third beam splitter, a sixth lens disposed between the third beam splitter and the wafer bump, and a fifth lens disposed between the third camera and the third beam splitter; The third beam splitter causes the optical paths of the projection device and the third camera to coincide outside the pattern projection unit and be perpendicular to the plane where the wafer bump is located. The pattern projection unit is also used to acquire the second image.

7. The system according to claim 1, characterized in that, The computing module is further used for: The spatial index is determined based on the position of the pixel corresponding to the wrapped phase in the stripe period of the stripe pattern; Determine the grayscale of the pixel corresponding to the wrapped phase; Based on the grayscale, a modulation index representing the pixel corresponding to the wrapping phase is determined; The quality indicators are determined based on the spatial indicators and the modulation indicators.

Images