Artificial Intelligence-Based Wafer Warpage Test System

Abstract

The present invention relates to an artificial intelligence-based wafer warpage testing system applied in the field of wafer testing technology. In this solution, both the initial inspection unit and the re-inspection unit are parallel to the wafer and perform inspection from the edge to the middle. Compared with the prior art, the situation of missed inspection during inspection can be greatly reduced, and the error of the inspection result can be reduced. During inspection, the initial inspection unit first performs a preliminary inspection on the wafer. After the wafer is qualified, the re-inspection unit inspects the wafer again. Moreover, when there is a local warpage defect at the inspection location, the re-inspection unit can also perform targeted concentrated re-inspection, so as to detect the longitudinal span and radial amplitude of the warpage. In addition, before the initial inspection, the position memory of the wafer can be self-adjusted, and the trajectory of its deviation can be recorded, so that the control center can provide positive feedback to the loading robot for fine-tuning, thereby effectively ensuring the accuracy of loading and reducing the deviation.

Description

Technical Field

[0001] The present invention relates to a wafer warpage testing system, and in particular to an artificial intelligence-based wafer warpage testing system applied in the field of wafer testing technology. Background Art

[0002] Before wafers leave the factory, they need to undergo rigorous tests such as warpage, thickness, and surface defects. They can only leave the factory after they pass all the tests. Warpage is a spatial measurement method used to express the degree of curvature of a plane in space. For a wafer, the smaller the warpage, the better the wafer quality, that is, the higher the flatness.

[0003] In the prior art, there are two methods for detecting wafer warpage:

[0004] Direct measurement method: Use a surface contact sensor or grating sensor to directly measure the surface deformation of the wafer, and then calculate the height difference at different positions on the wafer surface to obtain the warpage value.

[0005] Surface shape description method: Use a three-dimensional topography measuring instrument or microscope to scan or observe the wafer surface to obtain data on the wafer surface shape, and then calculate the warpage of the wafer by analyzing and processing the data.

[0006] In both of the above methods, the detection equipment is placed perpendicular to the wafer and then its surface is detected, which leads to missed detection of the wafer surface during the detection process, resulting in certain errors in the detection results. Summary of the invention

[0007] In view of the above-mentioned prior art, the technical problem to be solved by the present invention is that the prior art is prone to missed detections in wafer surface detection, resulting in certain errors in the detection results.

[0008] In order to solve the above problems, the present invention provides a wafer warpage test system based on artificial intelligence, including a control center, an automatic loading and unloading manipulator for loading and unloading wafers to be tested, a detection device and a comparison module, wherein the detection device, the automatic loading and unloading manipulator and the comparison module are all connected to the control center by signal;

[0009] The detection equipment includes a base plate, to which a test platform is fixedly connected, a detection cavity is drilled in the middle of the test platform, a position control hole is drilled at the bottom of the detection cavity, an electric push rod is fixedly installed at the bottom of the position control hole, a detection plate is provided in the detection cavity, the detection plate is fixedly connected to the extended end of the electric push rod, an initial inspection unit is provided at the mouth of the detection cavity, a re-inspection unit is provided inside the detection cavity, and both the initial inspection unit and the re-inspection unit are connected to the control center signal.

[0010] In the above-mentioned AI-based wafer warpage testing system, both the initial inspection unit and the re-inspection unit are parallel to the wafer and perform inspection from the edge to the middle. Compared with the existing technology, this can greatly reduce the number of missed inspections and reduce the error of the inspection results.

[0011] As a further improvement of the present application, the initial inspection unit includes a plurality of adjustment grooves bored in the mouth of the detection cavity and a plurality of initial inspection lasers respectively installed on the adjustment grooves. The laser emission ports of the plurality of initial inspection lasers are all facing one side of the axis of the detection plate, and the initial inspection lasers are connected to the control center signal.

[0012] As a further improvement of the present application, the middle of the emission port of the initial inspection laser is flush with the upper edge of the adjustment groove, and multiple initial inspection lasers are distributed in a ring array around the central axis of the detection plate.

[0013] As a further improvement of the present application, the re-inspection unit includes an annular groove bored on the inner wall of the detection cavity and a plurality of re-inspection lasers distributed in the annular groove in a circular array. An electric slide rail is installed on the vertical inner wall of the annular groove. The plurality of re-inspection lasers are all slidably connected to the electric slide rail, and the re-inspection laser and the electric slide rail are both connected to the control center signal.

[0014] As a further improvement of the present application, the distance between two adjacent initial detection lasers is greater than the distance between two adjacent re-detection lasers, and the former is 2-5 times of the latter.

[0015] As another improvement of the present application, a crystal sensing block is fixedly connected to one end of the initial inspection laser facing the axis of the inspection plate. The crystal sensing block is located above the emission port of the initial inspection laser, and the crystal sensing block and the emission port are respectively located above and inside the adjustment groove.

[0016] As another improved supplement of the present application, the crystal sensing block includes an outer shell fixedly connected to the initial inspection laser, an inner lining ring fixedly connected to the inside of the outer shell, a pressure sensing piece fixedly connected to the inside of the inner lining ring, the space enclosed by the inner lining ring, the pressure sensing piece and the end face of the outer shell facing the detection plate is filled with saturated air, a mounting plate is fixedly connected to the inner wall of the outer shell away from the detection plate, a pressure sensor is installed at the center of the mounting plate, the inner lining ring is fixedly connected to the mounting plate at the mouth of the mounting plate facing the mounting plate, and the pressure sensor is located on the inner side of the inner lining ring.

[0017] As another improved supplement of the present application, the pressure-sensitive sheet and the end of the housing facing the detection board are made of elastic sealing material, and the pressure-sensitive sheet bulges toward the pressure sensor, and the middle of the pressure-sensitive sheet contacts the pressure sensor.

[0018] As another improvement supplement of the present application, the inner lining ring is a hard and fixed trumpet-shaped structure, and the inner diameter of the mouth facing the detection plate side is large. There are four connection points between the inner lining ring and the outer shell, and the four connection points are respectively located on the front, rear, upper and lower inner walls of the outer shell.

[0019] In summary, the initial inspection unit and the re-inspection unit in this scheme are parallel to the wafer, and perform inspection from the edge to the middle. Compared with the existing technology, the missed inspection can be greatly reduced, and the error of the inspection result can be reduced. During the inspection, the initial inspection unit first performs a preliminary inspection on the wafer. After passing the inspection, the re-inspection unit inspects the wafer again. Moreover, when there is a local warping defect at the inspection point, the re-inspection unit can also perform targeted concentrated re-inspection, so as to detect the longitudinal span and radial amplitude of the warping. In addition, before the initial inspection, the position of the wafer can be self-adjusted and the deviation trajectory can be recorded, so that the control center can provide positive feedback to the loading robot for fine-tuning, thereby effectively ensuring the accuracy of loading and reducing deviation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a main principle block diagram of the first implementation method of this application;

[0021] Figure 2 This is a three-dimensional diagram of the first embodiment of the present application;

[0022] Figure 3 This is an exploded view of the first embodiment of the present application;

[0023] Figure 4 This is a three-dimensional diagram of the first embodiment of the present application after the detection plate is removed;

[0024] Figure 5 This is a comparison diagram of the detection chamber before and after the aggregation detection after the re-detection unit detects local warping in the first embodiment of the present application;

[0025] Figure 6 A cross-sectional view of a preliminary inspection unit portion of a second embodiment of the present application;

[0026] Figure 7 This is a schematic diagram of the initial inspection laser part of the second embodiment of the present application;

[0027] Figure 8 This is a partial comparison diagram of the wafer block before and after contact and compression between the wafer and the wafer when the wafer position is fine-tuned in the second embodiment of the present application.

[0028] Description of the numbers in the figure:

[0029] 1 bottom plate, 2 test platform, 201 position control hole, 202 detection cavity, 203 adjustment groove, 204 annular groove, 3 detection plate, 401 initial inspection laser, 402 re-inspection laser, 5 electric push rod, 6 sensing crystal block, 61 outer shell, 62 lining ring, 63 pressure sensing piece, 601 pressure sensor, 7 mounting plate. DETAILED DESCRIPTION

[0030] Two implementation modes of the present application are described in detail below with reference to the accompanying drawings.

[0031] The first implementation method:

[0032] Figure 1 The wafer warpage test system based on artificial intelligence is shown, including a control center, an automatic loading and unloading manipulator for loading and unloading wafers to be tested, a detection device and a comparison module, and the detection device, the automatic loading and unloading manipulator and the comparison module are all connected to the control center signal;

[0033] like Figure 2-3 The detection device includes a bottom plate 1, a test platform 2 is fixedly connected to the bottom plate 1, a detection cavity 202 is drilled in the middle of the test platform 2, a position control hole 201 is drilled at the bottom end of the detection cavity 202, an electric push rod 5 is fixedly installed at the bottom of the position control hole 201, a detection plate 3 is arranged in the detection cavity 202, the detection plate 3 is fixedly connected to the extended end of the electric push rod 5, the detection plate 3 can move up and down in the detection cavity 202 under the action of the electric push rod 5, and can rotate under the action of the electric shaft, so that the position of the wafer is adjusted during the wafer detection. Both the longitudinal and radial directions can be changed. An initial inspection unit is provided at the mouth of the detection cavity 202, and a re-inspection unit is provided inside the detection cavity 202. Both the initial inspection unit and the re-inspection unit are connected to the control center signal. The control hollow database stores the test data of the standard wafer under the same conditions. When the data measured by the initial inspection unit and the re-inspection unit are fed back to the control center, the control center will control the module to compare the data with the test data of the standard wafer. When the data difference exceeds the preset threshold, it means that it does not meet the standard.

[0034] The initial inspection unit includes a plurality of adjustment grooves 203 bored at the mouth of the detection cavity 202 and a plurality of initial inspection lasers 401 respectively installed on the adjustment grooves 203. The laser emission ports of the plurality of initial inspection lasers 401 are all facing one side of the axis of the detection plate 3. The initial inspection lasers 401 are connected to the control center signal.

[0035] The middle of the emission port of the initial inspection laser 401 is flush with the upper edge of the adjustment groove 203, and multiple initial inspection lasers 401 are distributed in a circular array around the central axis of the inspection plate 3. The diameter of the wafer is consistent with the inspection plate 3. During inspection, the automatic loading and unloading robot directly places the wafer on the inspection plate 3, and multiple initial inspection lasers 401 are turned on. Then the electric push rod 5 is shortened to control the wafer to descend, so that the light emitted by the multiple initial inspection lasers 401 is horizontally irradiated on the wafer. When the wafer is warped, the laser lengths emitted by the multiple initial inspection lasers 401 are different, so that the distance data obtained on the multiple initial inspection lasers 401 at the same time have obvious differences. When this situation exists, it means that it does not meet the standard, and the re-inspection unit does not need to re-inspect, which can effectively reduce unnecessary inspection volume. When there is little difference between multiple data, it can be compared with the standard data through the comparison unit. When the gap is within the threshold, it means that the initial inspection is qualified, and the electric push rod 5 controls the inspection plate 3 to move down, so as to re-inspect the wafer.

[0036] The re-inspection unit includes an annular groove 204 bored on the inner wall of the detection cavity 202 and a plurality of re-inspection lasers 402 distributed in the annular groove 204 in an annular array. An electric slide rail is installed on the vertical inner wall of the annular groove 204. The plurality of re-inspection lasers 402 are all slidably connected to the electric slide rail, and the re-inspection lasers 402 and the electric slide rail are both connected to the control center signal. When the wafer is re-inspected, when the edge of the wafer is facing the detection port of the re-inspection laser 402, when the data difference of the plurality of re-inspection lasers 402 is not large, the control center controls the electric shaft to rotate, thereby driving the wafer to rotate, and the rotation angle is greater than the angle between two adjacent re-inspection lasers 402, so that the wafer can be tested more comprehensively, effectively reducing the occurrence of missed detection, such as Figure 4 and Figure 5 When the data of some re-inspection lasers 402 are obviously larger than other data, it indicates that there is local warping. At this time, with the re-inspection laser 402 as the center, the electric slide rail can control multiple re-inspection lasers 402 on both sides to move closer to it and gather, and then detect again. Through the data of the multiple gathered re-inspection lasers 402, the radial amplitude of the wafer warping can be effectively detected, and the electric push rod 5 can be controlled to slowly extend and shorten, and the data changes of the same re-inspection laser 402 in the longitudinal range of the wafer thickness can be recorded, so that the longitudinal warping amplitude can be detected, and the general situation of the warping can be comprehensively obtained.

[0037] In addition, during the re-testing process, if there is no obvious difference in the data, the comparison unit can compare the data with the standard data again. When the difference is less than the threshold, it means that the wafer is qualified.

[0038] The distance between two adjacent initial detection lasers 401 is greater than the distance between two adjacent re-detection lasers 402, and the former is 2-5 times of the latter, so that the accuracy of the re-detection is greater than the accuracy of the initial detection.

[0039] In summary, the initial inspection unit and the re-inspection unit in this scheme are parallel to the wafer, and perform inspection from the edge to the middle. Compared with the existing technology, the missed inspection can be greatly reduced, and the error of the inspection result can be reduced. During the inspection, the initial inspection unit first performs a preliminary inspection on the wafer. After passing the inspection, the re-inspection unit inspects the wafer again. Moreover, when there is a local warping defect at the inspection location, the re-inspection unit can also perform targeted concentrated re-inspection, so as to detect the longitudinal span and radial amplitude of the warping.

[0040] The second implementation method:

[0041] Based on the first embodiment, this embodiment adds a crystal sensing block 6, and the rest of the parts are consistent with the first embodiment.

[0042] Figure 6 It is shown that the end of the initial inspection laser 401 facing the axis of the inspection plate 3 is fixedly connected with a crystal block 6, the crystal block 6 is located above the emission port of the initial inspection laser 401, and the crystal block 6 and the emission port are respectively located above and inside the adjustment slot 203, the crystal block 6 includes a shell 61 fixedly connected to the initial inspection laser 401, an inner lining ring 62 is fixedly connected inside the shell 61, a pressure-sensitive sheet 63 is fixedly connected inside the inner lining ring 62, the space enclosed by the inner lining ring 62, the pressure-sensitive sheet 63 and the end face of the shell 61 facing the inspection plate 3 is filled with saturated air, the inner wall of the shell 61 away from the inspection plate 3 is fixedly connected with a mounting plate 7, a pressure sensor 601 is installed at the center of the mounting plate 7, the inner lining ring 62 is fixedly connected to the mounting plate 7 towards the mouth of the mounting plate 7, and the pressure sensor 601 is located inside the inner lining ring 62;

[0043] After the automatic loading and unloading robot loads the material, the control center can control multiple initial inspection lasers 401 to move toward the inspection plate 3 at the same time, and then fine-tune the position of the wafer. When the wafer and the inspection plate 3 are intersecting, multiple wafer sensing blocks 6 do not contact them at the same time. One or more pressure sensors 601 will generate force data first. When multiple pressure sensors 601 generate force data at the same time, it means that the wafer position is accurate and there is no deviation between the wafer and the inspection plate 3.

[0044] During this process, the loading accuracy of the automatic loading and unloading robot can be determined according to the force conditions of multiple pressure sensors 601. Based on this data, the control center can adjust the automatic loading and unloading robot so that it can load materials accurately. After the wafer is loaded, there is no need to move it, thereby effectively ensuring the continuity of the subsequent detection process and effectively avoiding wear on the wafer caused by local position adjustment.

[0045] In addition, when the initial inspection laser 401 is moving, the end of the crystal sensing block 6 does not exceed the edge of the detection cavity 202, and stops moving when reaching the edge.

[0046] The pressure-sensitive piece 63 and the end of the shell 61 facing the detection plate 3 are made of elastic sealing material, and the pressure-sensitive piece 63 bulges toward the side of the pressure sensor 601, and the middle part of the pressure-sensitive piece 63 contacts the pressure sensor 601, so that when the position is adjusted, the crystal block 6 contacts the wafer, the elastic surface of the shell 61 is squeezed, and the compressed air therein can squeeze the pressure-sensitive piece 63, causing it to deform toward the pressure sensor 601, so that the pressure sensor 601 can respond quickly to generate force data, effectively ensuring the accuracy of the detection result. The inner lining ring 62 is a hard and fixed trumpet-shaped structure, and the inner diameter of the mouth facing the side of the detection plate 3 is large. There are four connection points between the inner lining ring 62 and the shell 61, and the four connection points are respectively located at the front, rear, upper and lower inner walls of the shell 61, so that there is no hard structure on the end face of the crystal block 6 facing the wafer, and the contact between the two is flexible contact, which effectively protects the wafer.

[0047] It is worth noting that during the test, the ambient temperature in the dust-free test workshop is first controlled to be stable so that there is no force data on the multiple pressure sensors 601, and then the test is performed.

[0048] In summary, in this embodiment, the position of the wafer can be memorized and adjusted before the initial inspection, and the trajectory of its deviation can be recorded, so that the control center can provide positive feedback to the loading robot and perform fine-tuning, thereby effectively ensuring the accuracy of loading and reducing loading deviation.

[0049] In view of current practical needs, the above-mentioned implementation mode adopted in this application is not limited to the scope of protection. Various changes made within the knowledge scope of technical personnel in this field without departing from the concept of this application still fall within the scope of protection of the present invention.

Claims

1. The wafer warpage test system based on artificial intelligence is characterized by: It includes a control center, an automatic loading and unloading manipulator for loading and unloading wafers to be inspected, a detection device and a comparison module, and the detection device, the automatic loading and unloading manipulator and the comparison module are all connected to the control center signal; The detection device comprises a base plate (1), a test platform (2) is fixedly connected to the base plate (1), a detection cavity (202) is bored in the middle of the test platform (2), a position control hole (201) is bored at the bottom end of the detection cavity (202), an electric push rod (5) is installed at the bottom of the position control hole (201) via an electric shaft, a detection plate (3) is provided in the detection cavity (202), the detection plate (3) is fixedly connected to the extended end of the electric push rod (5), an initial detection unit is provided at the mouth of the detection cavity (202), a re-detection unit is provided inside the detection cavity (202), and both the initial detection unit and the re-detection unit are connected to the control center signal; The initial inspection unit comprises a plurality of adjustment grooves (203) bored at the mouth of the detection cavity (202) and a plurality of initial inspection lasers (401) respectively mounted on the adjustment grooves (203), wherein the laser emission ports of the plurality of initial inspection lasers (401) are all directed toward one side of the axis of the detection plate (3), and the initial inspection lasers (401) are connected to the control center signal; The initial inspection laser (401) is installed in the adjustment groove (203) through an electric slide, and in an initial state, the initial inspection laser (401) contacts the inner wall of the adjustment groove (203) away from the detection plate (3), and one end of the initial inspection laser (401) facing the axis of the detection plate (3) is fixedly connected to a sensing crystal block (6), and the sensing crystal block (6) is located above the emission port of the initial inspection laser (401), and the sensing crystal block (6) includes a shell (61) fixedly connected to the initial inspection laser (401), and an inner lining ring (61) is fixedly connected to the inside of the shell (61). 2), a pressure-sensitive sheet (63) is fixedly connected to the inside of the inner lining ring (62), the space enclosed by the inner lining ring (62), the pressure-sensitive sheet (63) and the end surface of the outer shell (61) facing the detection plate (3) is filled with saturated air, a mounting plate (7) is fixedly connected to the inner wall of the outer shell (61) away from the detection plate (3), a pressure sensor (601) is installed at the center of the mounting plate (7), the inner lining ring (62) is fixedly connected to the mounting plate (7) at the mouth of the mounting plate (7), and the pressure sensor (601) is located on the inner side of the inner lining ring (62).

2. The wafer warpage testing system based on artificial intelligence according to claim 1, characterized in that: The middle of the emission port of the initial inspection laser (401) is flush with the upper edge of the adjustment slot (203), and a plurality of the initial inspection lasers (401) are distributed in a ring array around the central axis of the inspection plate (3).

3. The artificial intelligence-based wafer warpage testing system according to claim 2, characterized in that: The re-inspection unit comprises an annular groove (204) bored on the inner wall of the detection cavity (202) and a plurality of re-inspection lasers (402) distributed in the annular groove (204) in an annular array, an electric slide rail being installed on the vertical inner wall of the annular groove (204), the plurality of re-inspection lasers (402) being slidably connected to the electric slide rail, and the re-inspection lasers (402) and the electric slide rail being signal-connected to a control center.

4. The artificial intelligence-based wafer warpage testing system according to claim 3, characterized in that: The distance between two adjacent primary detection lasers (401) is greater than the distance between two adjacent secondary detection lasers (402), and the former is 2-5 times the latter.

5. The wafer warpage testing system based on artificial intelligence according to claim 1, characterized in that: The crystal sensing block (6) and the emission port are respectively located above and inside the adjustment groove (203).

6. The wafer warpage testing system based on artificial intelligence according to claim 1, characterized in that: The pressure-sensitive sheet (63) and the end of the housing (61) facing the detection plate (3) are made of elastic sealing material, and the pressure-sensitive sheet (63) bulges toward the side of the pressure sensor (601), and the middle of the pressure-sensitive sheet (63) is in contact with the pressure sensor (601).

7. The artificial intelligence-based wafer warpage testing system according to claim 6, characterized in that: The inner lining ring (62) is a hard, stereotyped trumpet-shaped structure, and the inner diameter of the opening facing the detection plate (3) is large. The inner lining ring (62) has four connection points with the outer shell (61), and the four connection points are respectively located at the front, rear, upper and lower inner walls of the outer shell (61).

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