Wafer detection device

Abstract

The embodiment of the present disclosure provides a wafer detection device, comprising: a stage for placing a wafer; the wafer is divided into multiple chips by scribe grooves after scribe processing; a laser device, opposite to the stage, for emitting a laser beam to the side of the stage where the wafer is placed; when the number of laser beams is three, the light spots formed by the three laser beams on the wafer meet the following conditions: the three light spots are the three vertices of a triangle, the line connecting any two light spots is not parallel to each scribe groove, and the length of the line connecting any two light spots is greater than a first threshold, which is the maximum size of the overlapping area of ​​two intersecting scribe grooves; the laser device is also used to sense the reflected laser beam; a processing device is used to determine the intensity of the reflected laser beam, and when the intensity of any reflected laser beam is greater than the intensity threshold, it is determined that there is a wafer on the stage. The embodiment of the present disclosure can improve the accuracy of wafer detection and reduce the misjudgment rate.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductor technology, and in particular to a wafer detection device. Background Art

[0002] Semiconductor components are electronic circuits formed on wafers through processes such as lithography, etching, various chemical deposition methods, and planarization. During wafer preparation, cleaning, polishing, and electroplating are required. During the tape-out process, the machine must detect whether the wafer is present. If the wafer is present, a robot (robot or manipulator) will remove the wafer to continue the subsequent process.

[0003] After steps such as scribing and cutting, the wafer becomes independent units. Each independent unit is a chip (or die). A laser sensor emits laser light and detects the intensity of the reflected laser light to determine whether a wafer is present on the machine. If the laser hits the scribe line created by scribing, the reflected laser light will be insufficient in intensity, leading to an erroneous judgment that the wafer does not exist. Summary of the Invention

[0004] The present disclosure provides a wafer inspection device that can improve the accuracy of detecting whether a wafer is present on a machine and reduce the error rate. The wafer inspection device includes:

[0005] A stage for placing a wafer; the wafer is divided into multiple chips by dicing grooves after dicing;

[0006] a laser device, opposite to the stage, for emitting a laser beam toward a side of the stage where the wafer is placed; when the number of the laser beams is three, light spots formed on the wafer by the three laser beams meet preset conditions, wherein the preset conditions are: the three light spots are three vertices of a triangle, a line connecting any two of the light spots is not parallel to an extension direction of each of the scribe lines, and a length of a line connecting any two of the light spots is greater than a first threshold value, wherein the first threshold value is a maximum size of an overlapping area of ​​two intersecting scribe lines;

[0007] The laser device is further used to sense the reflected laser beam;

[0008] The processing device is used to judge the intensity of the reflected laser beam, and determine that there is a wafer on the stage when the intensity of any reflected laser beam is greater than an intensity threshold.

[0009] In some embodiments, the wafer detection device further includes a motion device, and the laser device is located on the motion device; the motion device is capable of moving to control the position of the laser device through the movement of the motion device so that the three laser beams meet the preset conditions.

[0010] In some embodiments, the laser beam is perpendicular to a first plane, and the first plane is parallel to the surface of the wafer placed on the stage;

[0011] The motion device includes: a slide rail, a transmission shaft, and a fixing device; wherein the slide rail extends in a first direction, the transmission shaft can move on the slide rail in the first direction and in a direction opposite to the first direction, and the fixing device can rotate about an axis perpendicular to the first plane, and the first direction is parallel to the first plane;

[0012] The transmission shaft is connected to the slide rail and the fixing device respectively. The fixing device is located on the transmission shaft and is used to fix the laser device.

[0013] In some embodiments, the laser device includes a laser emitting device and a laser sensing device, and the motion device includes a first motion device and a second motion device; the laser emitting device is located on the first motion device, and the laser sensing device is located on the second motion device;

[0014] The first motion device is capable of moving, so as to control the position of the laser emitting device through the movement of the first motion device, so that the three laser beams meet the preset conditions;

[0015] The second motion device is movable to control the position of the laser sensing device through the movement of the second motion device, so that the laser sensing device can sense the reflected laser beam.

[0016] In some embodiments, the laser device is used to sequentially emit and sense at most three laser beams toward a side of the stage where the wafer is placed;

[0017] The processing device is used to control the laser device to stop emitting the remaining laser beams when it is detected for the first time that the intensity of the reflected laser beam is greater than the intensity threshold.

[0018] In some embodiments, the laser device includes three sub-laser devices;

[0019] The three sub-laser devices are used to sequentially emit three laser beams toward the side of the stage where the wafer is placed;

[0020] The processing device is used to control the remaining sub-laser devices that have not yet emitted laser beams to stop emitting laser beams when it is detected for the first time that the intensity of the reflected laser beam is greater than the intensity threshold.

[0021] In some embodiments, the wafer inspection device further includes a control module;

[0022] The control module is configured to receive a chip size and a scribe groove size, and based on the chip size and the scribe groove size, control the movement of the motion device so that the laser device emits a laser beam that meets the preset conditions;

[0023] And / or, the control module is configured to receive position information and control the movement of the motion device based on the position information so that the laser device emits a laser beam that meets the preset conditions.

[0024] In some embodiments, the preset condition further includes: a light spot formed by the first laser beam is located at the center of the wafer.

[0025] In some embodiments, the preset condition further includes: the length of a line connecting any two of the light spots is less than a second threshold, and the second threshold is the minimum size of the chip.

[0026] In some embodiments, the preset condition further includes: an acute angle between the first connecting line and the second connecting line and the target extension direction of the scribe line is greater than a preset angle;

[0027] In which, the first connecting line and the second connecting line are any two sides of the triangle, the extension direction of the scribe line includes a third direction and a fourth direction, the target extension direction is the third direction or the fourth direction, and the preset angle is the angle between the diagonal line of the area between two adjacent chips and the target extension direction.

[0028] In some embodiments, the processing device is further configured to determine that there is no wafer on the stage when the intensity of each of the reflected laser beams is not greater than the intensity threshold.

[0029] An embodiment of the present disclosure provides a wafer detection device, which avoids the three light spots from being formed on the scribe groove by increasing the number of laser irradiations and ensuring that the three laser beams meet preset conditions. As long as the reflection intensity of any laser beam is greater than the intensity threshold, it can be determined that there is a wafer on the stage, avoiding misjudgment caused by the laser hitting the scribe groove, improving the accuracy of wafer detection and reducing the misjudgment rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1A schematic diagram of using a laser sensor to detect wafers according to an embodiment of the present disclosure;

[0031] Figure 2 Schematic diagram of a wafer provided in an embodiment of the present disclosure Figure 1 ;

[0032] Figure 3 Schematic diagram of a wafer provided in an embodiment of the present disclosure Figure 2 ;

[0033] Figure 4 Schematic diagram of the light spot position provided in the embodiment of the present disclosure Figure 1 ;

[0034] Figure 5 A schematic structural diagram of a wafer inspection device provided in an embodiment of the present disclosure;

[0035] Figure 6 Schematic diagram of the light spot position provided in the embodiment of the present disclosure Figure 2 ;

[0036] Figure 7 Schematic diagram of the light spot position provided in the embodiment of the present disclosure Figure 3 ;

[0037] Figure 8 A schematic diagram of a sports device provided in an embodiment of the present disclosure;

[0038] Figure 9 A schematic diagram of a portion of the structure of a wafer inspection device provided in an embodiment of the present disclosure;

[0039] Figure 10 Schematic diagram of wafer inspection steps provided in the embodiment of the present disclosure Figure 1 ;

[0040] Figure 11 Schematic diagram of wafer inspection steps provided in the embodiment of the present disclosure Figure 2 . DETAILED DESCRIPTION

[0041] The following will be combined with the accompanying drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. It should be understood that the specific embodiments described herein are only used to illustrate the relevant disclosure and are not intended to limit the disclosure. It should also be noted that for ease of description, only the portions relevant to the relevant disclosure are shown in the drawings.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art in the art of the present disclosure. The terms used herein are only for the purpose of describing the embodiments of the present disclosure and are not intended to limit the present disclosure.

[0043] In the following description, reference is made to “some embodiments”, which describes a subset of all possible embodiments, but it will be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0044] It should be pointed out that the terms "first\second\third" involved in the embodiments of the present disclosure are only used to distinguish similar objects and do not represent a specific order for the objects. It can be understood that "first\second\third" can be interchanged with a specific order or sequence where permitted, so that the embodiments of the present disclosure described here can be implemented in an order other than that illustrated or described here.

[0045] like Figure 1 As shown in the figure, a laser sensor is used above the upper wafer position of the machine (i.e., the position where the wafer is placed) to determine whether there is a silicon wafer (i.e., wafer), and then the wafer-taking robot performs relevant actions.

[0046] Taking the 380mm process wafer chip as an example, the wafer will be divided into independent units through steps such as dicing and cutting. Figure 2 As shown in the figure, each independent unit is a chip (or die), and the chips are separated by dicing grooves formed by dicing. All chips are pasted on the blue film. Figure 3 As shown, due to various reasons, there may be no chips pasted on the blue film at some positions, that is, the blue film is not fully covered.

[0047] The reflectivity of the silicon wafer to the laser is high, while the reflectivity of the blue film is low, and the intensity of the reflected light is lower than the threshold that the laser sensor can sense. Figure 4 As shown in the figure, under normal circumstances, when the laser hits the chip, the intensity of the reflected light is greater than the threshold, and the presence of the wafer can be sensed normally. However, under abnormal circumstances, due to the different sizes of die products, the presence of scribe grooves, incomplete blue film, etc., if the laser emitted by the laser sensor hits the scribe grooves or blue film, it may cause a false alarm. This is because the intensity of the reflected light does not reach the threshold, triggering a no wafer error, which makes the wafer-picking robot unable to pick up the wafer and the tool hangs.

[0048] Based on this, an embodiment of the present disclosure provides a wafer detection device, including: a stage for placing a wafer; the wafer is divided into multiple chips by scribe grooves after scribe processing; a laser device, opposite to the stage, for emitting a laser beam to the side of the stage where the wafer is placed; when the number of laser beams is three, the light spots formed by the three laser beams on the wafer meet preset conditions, and the preset conditions are: the three light spots are the three vertices of a triangle, the line connecting any two light spots is not parallel to the extension direction of each scribe groove, and the length of the line connecting any two light spots is greater than a first threshold, and the first threshold is the maximum size of the overlapping area of ​​the two intersecting scribe grooves; the laser device is also used to sense the reflected laser beam; the processing device is used to judge the intensity of the reflected laser beam, and when the intensity of any reflected laser beam is greater than the intensity threshold, it is determined that there is a wafer on the stage.

[0049] In this way, by increasing the number of laser irradiations and ensuring that the three laser beams meet the preset conditions, it is possible to avoid the three light spots being formed on the scribe groove. As long as the reflection intensity of any laser beam is greater than the intensity threshold, it is possible to determine that there is a wafer on the stage, thus avoiding misjudgment caused by the laser hitting the scribe groove, improving the accuracy of wafer detection, and reducing the misjudgment rate. Compared with the visual solution, due to the limited space of the machine, the camera's field of view is limited within a certain range, making it difficult to capture the entire wafer. In addition, the visual solution requires the configuration of a light source system, a light receiving detector, a camera, etc. at the wafer loading position. The overall structure is complex and the cost is high. It also requires built-in complex software algorithms, which are difficult to configure. The laser solution used in the embodiment of the present disclosure does not have such problems, and has the advantages of low cost and simpler implementation.

[0050] The embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0051] In one embodiment of the present disclosure, see Figure 5 , which shows a schematic diagram of the composition structure of a wafer detection device 10 provided by an embodiment of the present disclosure. Figure 5 As shown, the wafer inspection device 10 includes:

[0052] The stage 101 is used to place the wafer; the wafer is divided into multiple chips by the dicing grooves after dicing;

[0053] The laser device 102 is opposite to the stage 101 and is used to emit a laser beam toward the side of the stage 101 where the wafer is placed. When there are three laser beams, the light spots formed by the three laser beams on the wafer meet preset conditions, which are: the three light spots are the three vertices of a triangle, the line connecting any two of the light spots is not parallel to the extension direction of each scribe line, and the length of the line connecting any two of the light spots is greater than a first threshold value, which is the maximum size of the overlapping area of ​​two intersecting scribe lines.

[0054] The laser device 102 is also used to sense the reflected laser beam;

[0055] The processing device 103 is used to determine the intensity of the reflected laser beams, and determine that there is a wafer on the stage 101 when the intensity of any reflected laser beam is greater than an intensity threshold.

[0056] It should be noted that the function of the stage 101 is to place the wafer. Figure 5 In the embodiment, the machine platform and the frame for carrying / fixing wafers are used as the stage 101 as an example. In other examples, it can also be a holding cavity for holding wafers, etc., and there is no specific limitation on this.

[0057] It should also be noted that laser device 102 is a device capable of emitting and sensing a laser beam. The specific components for emitting and sensing the laser beam may be separate or integrated, and this is not specifically limited. For example, laser device 102 may be a laser sensor (referred to as a laser).

[0058] Unlike traditional laser sensors, in the embodiment of the present disclosure, the laser device 102 does not only emit a beam of laser to a fixed position to determine whether a wafer exists, but can emit multiple beams of laser to different positions to comprehensively determine whether a wafer exists, as described in detail below.

[0059] like Figure 5 As shown, a wafer is placed on stage 101. To ensure that the laser beam can hit the wafer smoothly, a laser device 102 is set on the side of stage 101 where the wafer is placed, that is, above stage 101. When detecting whether there is a wafer on stage 101, laser device 102 emits a laser toward the side of stage 101 where the wafer is placed. If there is a wafer on stage 101, the laser will hit the wafer and be reflected by the wafer. Then, laser device 102 will sense the laser beam reflected back by the wafer. Processing device 103 will judge the intensity of the reflected laser beam. If the intensity is greater than the intensity threshold, it means that there is a wafer on stage 101. Here, the intensity threshold is the critical value that can distinguish the intensity of the laser reflected by the silicon wafer.

[0060] The wafer is diced to form dicing grooves, and the blue film may not be fully applied. As mentioned above, the silicon wafer has a high reflectivity to laser, while the blue film has a low reflectivity to laser. If the laser hits the blue film, the intensity of the reflected laser beam will not reach the intensity threshold, and the processing device 103 will mistakenly determine that there is no laser, resulting in the inability to remove the wafer.

[0061] To solve this problem, in the embodiment of the present disclosure, the laser device 102 emits multiple laser beams to different positions above the stage 101 to eliminate the possibility of the laser beam hitting the scribe line. By properly designing the position of the laser emission, it is possible to emit at most three laser beams to determine whether there is a wafer on the stage 101. Figure 5 As shown, the laser device 102 emits three laser beams A, B, and C respectively, forming three corresponding light spots on the wafer. The three light spots form a triangle, and the three light spots are the three vertices of the triangle, that is, the three light spots are not located on the same straight line.

[0062] Take the four dies located in the center of the wafer as an example. Figure 6 As shown, there is a scribe groove between the two dies, and the width of the scribe groove is L. Figure 6 In the figure, the four dies are divided by two scribe lines, scribe line 1 and scribe line 2, and A, B, and C represent the corresponding light spots formed by the three laser beams.

[0063] like Figure 6 As shown, the width of scribe line 1 and scribe line 2 are both L, and they are perpendicular to each other. The extension direction of scribe line 1 is the x direction (also recorded as the third direction), and the extension direction of scribe line 2 is the y direction (also recorded as the fourth direction). The overlapping area of ​​the two scribe lines is a square, so: the maximum size of the overlapping area = the first threshold a = the diagonal length of the square, that is, Figure 6 The diameter a of the solid small circle in the figure.

[0064] It should also be noted that in actual production, the intersecting scribe lines are usually vertical, but it is not ruled out that there may be special cases such as other angles. In this case, the overlapping area may be a rhombus, and the first threshold is the maximum diagonal of the rhombus. In the embodiments of this disclosure, the mutually perpendicular scribe lines are taken as an example, and the first threshold a= L.

[0065] Thus, in the embodiment of the present disclosure, the line connecting any two light spots is not parallel to each scribe groove (obviously, it is also not perpendicular to each scribe groove), that is, it is not parallel and perpendicular to the x-direction, nor is it parallel and perpendicular to the y-direction, and the length of the line connecting any two light spots is greater than the first threshold a, thereby avoiding as much as possible the possibility of all three light spots hitting the scribe groove. Then, in the case of emitting three laser beams, at least one laser beam will hit the die, and as long as one laser beam hits the die, the processing device 103 will determine that there is a wafer, which greatly avoids misjudgment. Generally, using lasers to sense wafers in a machine chamber is a common and widespread practice, which has the advantages of high efficiency, accuracy, and low cost. The embodiment of the present disclosure follows the laser solution, and all similar problems can be solved by increasing the number of irradiations to form an irregular triangle. The structure is very easy to implement and has the characteristics of low cost, simple algorithm and structure.

[0066] It should also be noted that to further improve detection accuracy, the preset conditions also include: the light spot formed by the first laser beam is located at the center of the wafer. Furthermore, the preset conditions also include: the length of the line connecting any two light spots is less than a second threshold, which is the minimum chip size.

[0067] It should be noted that the above limits the minimum length of the light spot line, and here the maximum length of the light spot line is also limited, and the maximum length of the light spot line is limited to within the second threshold. Figure 6 As shown in the figure, for a rectangular chip, its minimum size is the length m of its short side, that is, the second threshold is m. If the chip is square, the second threshold is its side length. In this way, a circle can be obtained with the position of the first light spot as the center and the second threshold as the radius. The triangle formed by the three light spots is confined within the circle, thus avoiding the situation where the two light spots do not hit the same scribe groove, but cross a die and hit another scribe groove. For example, the positions of the three light spots are as follows: Figure 6 As shown in A, D, and E.

[0068] It should also be noted that this solution limits the laser emission range of the laser device 102 to no more than the range of the area where the wafer is placed on the stage 101, that is, if a wafer is present, the laser beam will not hit outside the wafer, and may only hit non-die areas. The disclosed embodiment also limits the position of the first light spot to the center of the wafer. In this way, the formation positions of the three light spots are limited to several chips near the center of the wafer. If the center of the wafer is a scribe groove, then based on the preset conditions, the remaining two light spots can basically ensure that at least one hits the chip. If the center of the wafer is the chip, it can be directly determined that the wafer exists. In the case where the blue film is not fully applied, the light spot can also be formed on other nearby chips to increase the reliability and accuracy of the detection.

[0069] Furthermore, based on the limitations of the aforementioned preset conditions, and the light spots have a certain size, the line connecting the two light spots is not parallel to the extension direction of any scribe groove, and the length of the line connecting the two light spots is greater than the first threshold and less than the second threshold, the problem of misjudgment caused by the three light spots being formed on the scribe groove can basically be avoided. However, if the width of the scribe groove is large, the following may occur: Figure 7 The situation shown ( Figure 7 The three vertices of the middle triangle are the positions where the light spots are formed): that is, although the three light spots meet the aforementioned preset conditions, they are still all formed on the scribe line. Therefore, the preset conditions can be further limited in the embodiment of the present disclosure.

[0070] The preset condition may further include: an acute angle between the first connecting line and the second connecting line and the target extension direction of the scribe line is greater than a preset angle;

[0071] Among them, the first connecting line and the second connecting line are any two sides of the triangle, the extension direction of the scribe groove includes the third direction and the fourth direction, the target extension direction is the third direction or the fourth direction, and the preset angle is the angle (acute angle) between the diagonal line of the area between two adjacent chips and the target extension direction.

[0072] like Figure 7 As shown, the scribe line between the two chips forms a rectangle, and the diagonal length of the rectangle is c or d. It can be understood that if the chip is square, then c=d. Assuming that the target extension direction is the x direction (i.e., the third direction), the diagonal length of the area between two adjacent chips is Figure 7 The line segment with a length of c in the middle has an angle of α1 with the x-direction. Assuming that the target extension direction is the y-direction (i.e., the fourth direction), the diagonal line of the area between two adjacent chips is Figure 7 The line segment with a length of d makes an angle α2 with the y direction.

[0073] Taking the target extension direction as the x direction as an example, by calculating the corresponding inverse trigonometric function with any two of L, c, and m, the specific angle value of α1 can be obtained. I will not go into details here. The same applies when the target extension direction is the y direction.

[0074] In some embodiments, the wafer inspection device 10 further includes a motion device, and the laser device 102 is located on the motion device; the motion device is capable of moving to control the position of the laser device 102 through the movement of the motion device so that the three laser beams meet preset conditions.

[0075] It should be noted that the laser device 102 can be set on a motion device that can move (such as translation, rotation, etc.), so that the movement of the motion device drives the laser device 102 to change position, thereby achieving the emission of laser beams at different positions.

[0076] The following examples illustrate several specific implementations of the motion device. In the disclosed embodiment, the motion device may be denoted by 104. Before introducing the specific implementation of the motion device 104, a first plane is first defined: the first plane is parallel to the surface of the wafer placed on the stage 101. That is, when the wafer is placed stably and without tilt on the stage 101, the plane on which the surface of the wafer lies is denoted as the first plane. For example, the first plane is a horizontal plane.

[0077] In one implementation, Figure 8 As shown, the laser beam is perpendicular to the first plane, and the motion device 104 may include: a slide rail 1041, a transmission shaft 1042, and a fixing device 1043; wherein the slide rail 1041 extends in a first direction, the transmission shaft 1042 can move on the slide rail 1041 in the first direction and in a direction opposite to the first direction, and the fixing device 1043 can rotate about an axis perpendicular to the first plane as a rotation axis, and the first direction is parallel to the first plane;

[0078] The transmission shaft 1042 is connected to the slide rail 1041 and the fixing device 1043 respectively. The fixing device 1043 is located on the transmission shaft 1042 and is used to fix the laser device 102 .

[0079] It should be noted that the rotation axis is parallel to the direction of the laser beam. Figure 8 As shown, assuming the first direction is right, the transmission shaft 1042 can drive the fixture 1043 and the laser device 102 fixed to the fixture 1043 to slide left or right on the slide rail 1041; at the same time, the fixture 1043 can rotate. In this way, by cooperating with the slide rail 1041, the transmission shaft 1042, and the fixture 1043, and setting the movement direction and distance of the transmission shaft 1042, as well as the rotation angle of the fixture 1043, the laser device 102 can be driven to a desired position to emit a laser beam that meets preset conditions.

[0080] It should also be noted that the fixing device 1043 can fix the laser device 102 by, for example, clamping, gluing, etc., which is not specifically limited.

[0081] In addition, based on the aforementioned preset conditions, the movement radius of the laser device 102 driven by the motion device 104 is a second threshold.

[0082] In another possible implementation, Figure 9As shown, the laser device 102 includes a laser emitting device 1021 and a laser sensing device 1022, and the motion device 104 includes a first motion device 1044 and a second motion device 1045; the laser emitting device 1021 is located on the first motion device 1044, and the laser sensing device 1022 is located on the second motion device 1045;

[0083] The first motion device 1044 is capable of moving, so as to control the position of the laser emitting device 1021 by the movement of the first motion device 1044 so that the three laser beams meet the preset conditions;

[0084] The second motion device 1045 is movable to control the position of the laser sensing device 1022 through the movement of the second motion device 1045 , so that the laser sensing device 1022 can sense the reflected laser beam.

[0085] It should be noted that in the aforementioned Figure 8 In the example described, the laser beam is directed perpendicularly to the first plane. Figure 9 In the example shown, the laser beam may not be perpendicular to the wafer surface, but may be directed at the wafer at other angles. That is to say, the first motion device 1044 is a motion device that can rotate at any angle, or the rotation angle of the first motion device 1044 can at least enable the laser emitting device 1021 to satisfy the requirement of emitting laser at a certain angle to the wafer located below it. Here, the first motion device 1044 may be composed of a first rotating device and a fixing device, the first rotating device realizes rotation, and the fixing device realizes fixing of the laser emitting device 1021. Correspondingly, since the emission angle of the laser is not vertical, after each laser emission, the second motion device 1045 needs to move to drive the laser sensing device 1022 to a suitable position to ensure that the reflected laser can be sensed. Therefore, the second motion device 1045 .... Figure 8 The shown movement device is realized in combination with the first rotation device.

[0086] In summary, this solution avoids and resolves false alarms by designing a 3-point irregular solution. It is applicable to all types of equipment for determining the presence or absence of wafers and will not trigger false alarms. The central idea is the application of irregular triangles, that is, under the constraints of preset conditions, three light spots form an irregular triangle. Such three laser beams can basically avoid false alarms (one or two are very likely to hit the scribe groove at the same time). Among them, the line connecting any light spot is not perpendicular to the cutting path (i.e., the scribe groove), which can avoid the three light spots hitting the scribe groove at the same time; the distance between any two light spots is greater than L is smaller than the chip size, ensuring the beam spot falls within the die. Ultimately, this movable three-spot laser can cover any different chip size design rules, ensuring accurate judgment with just three shots, making it suitable for all tools that require wafer judgment after dicing.

[0087] Furthermore, in some embodiments, the laser device 102 is used to sequentially emit and sense up to three laser beams toward the side of the stage 101 where the wafer is placed; the processing device 103 is used to control the laser device 102 to stop emitting the remaining laser beams when the intensity of the reflected laser beam is first detected to be greater than an intensity threshold.

[0088] Alternatively, in some other embodiments, the laser device 102 may include three sub-laser devices; the three sub-laser devices are configured to sequentially emit three laser beams toward a side of the stage 101 where the wafer is placed;

[0089] The processing device 103 is configured to control the remaining sub-laser devices that have not yet emitted laser beams to stop emitting laser beams when it is detected for the first time that the intensity of the reflected laser beam is greater than the intensity threshold.

[0090] It should be noted that in the embodiment of the present disclosure, one laser device 102 may emit three laser beams in sequence, or three sub-laser devices may emit three laser beams simultaneously or in sequence, and the processing device 103 may judge the intensity of the reflected laser beams in sequence or together.

[0091] If the three laser beams are emitted in sequence and the processing device 103 makes judgments in sequence, then as long as it is determined that the intensity of one reflected laser beam is greater than the intensity threshold, the subsequent laser beams do not need to be emitted. At this time, the processing device 103 can control the laser device 102 to stop emitting lasers.

[0092] It should also be noted that if Figure 5 As shown, the processing device 103 may specifically include a signal collection and processing device 1031 and a determination device 1032; wherein:

[0093] The signal collection and processing device 1031 is connected to the laser device 102 (specifically, the laser sensing device) and is used to determine the intensity of the reflected laser light and send it to the determination device 1032;

[0094] The determination device 1032 is used to compare the intensity of the reflected laser light with a preset threshold value, and determine that there is a wafer on the stage 101 when the intensity of any reflected laser beam is greater than the intensity threshold value; and determine that there is no wafer on the stage 101 when the intensity of each reflected laser beam is not greater than the intensity threshold value.

[0095] Illustratively, the portion of the laser device 102 that emits laser light may include a laser emitting diode, and the emitted laser beam may be a laser pulse; the portion of the laser device 102 that senses the reflected laser light may include an avalanche photodiode for detecting the optical signal and converting it into a corresponding electrical signal, and the signal collection and processing device 1031 may detect the current value of the electrical signal as the intensity, which is then judged by the determination device 1032.

[0096] It should also be noted that in addition to determining whether a wafer exists by irradiating the upper wafer position with a laser, the embodiment of the present disclosure can also determine whether other parameters of the wafer (such as size) meet the requirements. Therefore, the embodiment of the present disclosure can also be set with load sensing to determine whether the wafer is a wafer that meets the requirements (such as a 380mm iron ring wafer). If the wafer does not meet the requirements, the machine will also report an error.

[0097] Furthermore, in some embodiments, the wafer inspection apparatus 10 may further include a control module (not shown in the drawings); the control module is configured to receive the chip size and the scribe groove size, and based on the chip size and the scribe groove size, control the movement of the motion device 104 so that the laser device 102 emits a laser beam that meets preset conditions;

[0098] And / or, the control module is configured to receive the position information and control the movement of the motion device 104 based on the position information so that the laser device 102 emits a laser beam that meets a preset condition.

[0099] It should be noted that the position of the laser beam emitted by the laser device 102 can be controlled by a control module. For example, the control module can be a processor, a chip, etc. The control module can be implemented by software or hardware or a combination of software and hardware, and there is no specific limitation on this.

[0100] In actual production, the user can input or the control module can automatically obtain the chip size and scribe groove size in the current batch of wafers, and then automatically plan three laser beams that meet the preset conditions based on the chip size and scribe groove size.

[0101] It should also be noted that the emission position of the laser beam can also be input by the user, that is, the position information here can be set according to the input method matched with the control module. The position information can be coordinates, but is not limited to coordinates.

[0102] For example, for the aforementioned Figure 8 Assume that the position of the first laser beam emission is fixed to the center of the wafer, then the movement distance and direction (forward or reverse) of the slide rail 1041 and the rotation angle of the transmission shaft 1042 can be input respectively. Figure 9 The illustrated motion device 104 still assumes that the position of the first laser beam emission is fixed to the center of the wafer. The subsequent movement distances and directions of the first motion device 1044 and the second motion device 1045 can be input separately. Alternatively, custom coordinates can be input to achieve position control.

[0103] Furthermore, this solution can achieve wafer detection by emitting at most three laser beams. In practice, in order to further ensure accuracy, the number of emitted laser beams can be increased, for example, to four or five beams, but at least three of the laser beams still meet the preset conditions, or the combination of all three laser beams meets the preset conditions.

[0104] See also Figure 10 , which shows a schematic diagram of a wafer inspection process provided by an embodiment of the present disclosure Figure 1 .like Figure 10 Shown, including:

[0105] S1101: The laser emitting device emits lasers A, B, and C.

[0106] It should be noted that the lasers A, B, and C are laser beams A, B, and C.

[0107] S1102: The signal collection and processing device 1031 collects the intensities of lasers A, B, and C.

[0108] S1103: The determination means 1032 determines whether the following condition is satisfied: the strength of any signal > the strength threshold.

[0109] S1104: The determination device 1032 determines that there is a wafer at the loading position.

[0110] It should be noted that if the judgment result is no, the judgment device 1032 determines that there is no wafer at the loading position.

[0111] The embodiment of the present disclosure designs a motion platform based on a slide rail, a transmission shaft, and a fixing device above the machine table / chamber. Figure 8 As shown in the figure, the transmission shaft moves forward and backward in the extension direction of the slide rail (i.e., the first direction and the opposite direction of the first direction) to control the distance, and the fixing device can rotate 360° on the transmission shaft to control the angle; for different products, the chip size (die pitch) value and the scribe groove size (L value) are input, or the movement distance and angle can be customized according to the product design method (recipe) program; before loading and unloading, the motion platform controls the laser to move to the center of the circle based on the chip information to emit laser A; for example, the customized motion language is 0.8X corresponding to Figure 6 Laser B is emitted at a medium angle of 45°; the custom motion language corresponds to 0.6X Figure 6Laser C is emitted at a middle angle of 30°; the received reflected light signals are processed in sequence, and the presence of a wafer is determined based on the design logic to control the next action of the machine (three shots in sequence form an irregular triangle).

[0112] It should also be noted that the intensity of the three reflected laser beams can be determined after all three laser beams are emitted; or, it can be determined once each laser beam is emitted. The specific process can be found in Figure 11 , which shows a schematic diagram of a wafer inspection process provided by an embodiment of the present disclosure Figure 2 .like Figure 11 Shown, including:

[0113] S1201: The laser emitting device emits laser A.

[0114] S1202: The signal collection and processing device 1031 collects the intensity of laser A.

[0115] S1203: The determination means 1032 determines whether the following conditions are met: signal strength > strength threshold.

[0116] If the judgment result is yes, execute step S1204; otherwise, execute step S1205.

[0117] S1204: The determination device 1032 determines that there is a wafer at the loading position.

[0118] S1205: The laser emitting device emits laser B.

[0119] S1206: The signal collection and processing device 1031 collects the intensity of laser B.

[0120] S1207: The determination means 1032 determines whether the following condition is satisfied: signal strength > strength threshold.

[0121] If the judgment result is yes, execute step S1208; otherwise, execute step S1209.

[0122] S1208: The determination device 1032 determines that there is a wafer at the loading position.

[0123] S1209: The laser emitting device emits laser C.

[0124] S12010: The signal collection and processing device 1031 collects the intensity of laser B.

[0125] S12011: The determination device 1032 determines whether the following conditions are met: signal strength > strength threshold.

[0126] If the judgment result is yes, execute step S12012; otherwise, execute step S12013.

[0127] S12012: The determination device 1032 determines that there is a wafer at the loading position.

[0128] S12013: The determination device 1032 determines that there is no wafer at the loading position.

[0129] It should be noted that, for example Figure 6 As shown, the line connecting spot B and spot A is controlled to have a 45° angle with the opposite x-direction, with a straight-line distance of 0.5mm. The line connecting spot C and spot A is controlled to have a 30° angle with the x-direction, with a straight-line distance of 0.4mm. Three laser beams are designed to act sequentially, and their spot illumination positions meet preset conditions. For all different die-size design rules, this solution ensures that at least one spot will not fall on the scribe line, causing a false alarm. It is also applicable to all equipment used for dicing wafers (e.g., 380mm wafers).

[0130] The above description is merely a preferred embodiment of the present disclosure and is not intended to limit the scope of protection of the present disclosure.

[0131] It should be noted that, in this disclosure, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0132] The serial numbers of the above-mentioned embodiments of the present disclosure are for description only and do not represent the advantages or disadvantages of the embodiments.

[0133] The methods disclosed in the several method embodiments provided in this disclosure can be arbitrarily combined without conflict to obtain new method embodiments.

[0134] The features disclosed in the several product embodiments provided in this disclosure can be arbitrarily combined without conflict to obtain new product embodiments.

[0135] The features disclosed in several method or device embodiments provided in this disclosure may be arbitrarily combined without conflict to obtain new method embodiments or device embodiments.

[0136] The above description is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any technician familiar with the technical field can easily think of changes or replacements within the technical scope disclosed in the present disclosure, and they should all be covered by the protection scope of the present disclosure.

Claims

1. A wafer inspection device, characterized in that: include: A stage for placing wafers; The wafer is divided into a plurality of chips by dicing grooves after dicing; a laser device, opposite to the stage, for emitting a laser beam toward the side of the stage where the wafer is placed; When the number of the laser beams is three, light spots formed on the wafer by the three laser beams meet preset conditions, wherein the preset conditions are: the three light spots are three vertices of a triangle, a line connecting any two of the light spots is not parallel to an extension direction of each of the scribe lines, and a length of a line connecting any two of the light spots is greater than a first threshold, where the first threshold is a maximum size of an overlapping area of ​​two intersecting scribe lines in the extension direction; The laser device is further used to sense the reflected laser beam; The processing device is used to judge the intensity of the reflected laser beam, and determine that there is a wafer on the stage when the intensity of any reflected laser beam is greater than an intensity threshold.

2. The wafer inspection device according to claim 1, wherein: The wafer detection device also includes a motion device, and the laser device is located on the motion device; the motion device is capable of moving to control the position of the laser device through the movement of the motion device so that the three laser beams meet the preset conditions.

3. The wafer inspection device according to claim 2, wherein: The laser beam is perpendicular to a first plane, and the first plane is parallel to the surface of the wafer placed on the stage; The motion device includes: a slide rail, a transmission shaft, and a fixing device; wherein the slide rail extends in a first direction, the transmission shaft can move on the slide rail in the first direction and in a direction opposite to the first direction, and the fixing device can rotate about an axis perpendicular to the first plane, and the first direction is parallel to the first plane; The transmission shaft is connected to the slide rail and the fixing device respectively. The fixing device is located on the transmission shaft and is used to fix the laser device.

4. The wafer inspection device according to claim 2, wherein: The laser device includes a laser emitting device and a laser sensing device, and the motion device includes a first motion device and a second motion device; the laser emitting device is located on the first motion device, and the laser sensing device is located on the second motion device; The first motion device is capable of moving, so as to control the position of the laser emitting device through the movement of the first motion device, so that the three laser beams meet the preset conditions; The second motion device is movable to control the position of the laser sensing device through the movement of the second motion device, so that the laser sensing device can sense the reflected laser beam.

5. The wafer inspection device according to claim 1, wherein: The laser device is used to sequentially emit and sense at most three laser beams toward the side of the stage where the wafer is placed; The processing device is used to control the laser device to stop emitting the remaining laser beams when it is detected for the first time that the intensity of the reflected laser beam is greater than the intensity threshold.

6. The wafer inspection device according to claim 5, characterized in that: The laser device includes three sub-laser devices; The three sub-laser devices are used to sequentially emit three laser beams toward the side of the stage where the wafer is placed; The processing device is used to control the remaining sub-laser devices that have not yet emitted laser beams to stop emitting laser beams when it is detected for the first time that the intensity of the reflected laser beam is greater than the intensity threshold.

7. The wafer inspection device according to claim 2, wherein: The wafer detection device also includes a control module; The control module is configured to receive a chip size and a scribe groove size, and based on the chip size and the scribe groove size, control the movement of the motion device so that the laser device emits a laser beam that meets the preset conditions; And / or, the control module is configured to receive position information and control the movement of the motion device based on the position information so that the laser device emits a laser beam that meets the preset conditions.

8. The wafer inspection device according to any one of claims 1 to 7, characterized in that: The preset condition also includes: a light spot formed by the first laser beam is located at the center of the wafer.

9. The wafer inspection device according to any one of claims 1 to 7, characterized in that: The preset condition further includes: the length of a line connecting any two of the light spots is less than a second threshold, and the second threshold is the minimum size of the chip.

10. The wafer inspection device according to any one of claims 1 to 7, characterized in that: The preset condition further includes: an acute angle between the first connecting line and the second connecting line and the target extension direction of the scribe line is greater than a preset angle; In which, the first connecting line and the second connecting line are any two sides of the triangle, the extension direction of the scribe line includes a third direction and a fourth direction, the target extension direction is the third direction or the fourth direction, and the preset angle is the angle between the diagonal line of the area between two adjacent chips and the target extension direction.

11. The wafer inspection device according to any one of claims 1 to 7, characterized in that: The processing device is further configured to determine that no wafer exists on the stage when the intensity of each of the reflected laser beams is not greater than the intensity threshold.

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