Wafer state detection method and wafer state detection apparatus

Abstract

The application relates to the technical field of wafer scanning, and provides a wafer state detection method and a wafer state detection device, the method comprising the following steps: controlling a first pair of through transmission sensors and a second pair of through transmission sensors to scan a wafer; the two pairs of through transmission sensors have a horizontal distance difference and a vertical height difference; determining position information of a mounting frame when the first pair of through transmission sensors and the second pair of through transmission sensors switch to a triggered state and a non-triggered state; determining first state information of the wafer based on the position information, the horizontal distance difference and the vertical height difference, wherein the first state information comprises a front-back tilting state and a non-front-back tilting state; and the front-back tilting degree of the wafer can be accurately calculated according to the position information when the two pairs of sensors switch to the triggered state and the non-triggered state in sequence, in combination with the horizontal distance difference and the vertical height difference, so that the front-back tilting state of the wafer is determined; meanwhile, the scanning data of the two pairs of through transmission sensors can be verified with each other, the accuracy of scanning is improved, and the wafer breakage risk is reduced.

Description

Technical Field

[0001] This invention relates to the field of wafer scanning technology, and in particular to a wafer condition detection method and a wafer condition detection device. Background Technology

[0002] During the manufacturing process, wafers are generally stored in wafer cassettes. The support frame of the wafer cassette has multiple wafer slots arranged from top to bottom for holding the wafers in place. The wafers are held in place by their edges and stacked on the support frame from bottom to top. Before operating the wafers, the wafer loader needs to scan and map the wafers in the wafer cassette and feed the scanned values ​​back to the system for comparison to determine the safety of the manufacturing process. During the scan, the relevant status of the wafers in the wafer cassette is detected, such as whether they are stacked (double), cross, or whether they are present or absent.

[0003] As the semiconductor industry strives to reduce costs and increase efficiency, more and more types of wafer cassettes are being used in the integrated circuit manufacturing process. Abnormal wafer placement is becoming increasingly common. However, current wafer loaders can only detect the left and right tilt of the wafer, not the front and back tilt, and their detection accuracy is generally low, resulting in a high risk of damage during wafer handling. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in related technologies. To this end, this invention proposes a wafer condition detection method that addresses the shortcomings of existing detection methods, such as the inability to detect the forward and backward tilt of wafers and low detection accuracy.

[0005] The present invention also proposes a wafer state detection device for detecting the state of a wafer.

[0006] A wafer condition detection method according to a first aspect of the present invention includes:

[0007] The first and second through-beam sensors are controlled to scan the wafer; wherein the first and second sensors are mounted on a mounting bracket, and there is a horizontal distance difference and a vertical height difference between the first and second through-beam sensors;

[0008] Determine the position information of the first and second through-beam sensors when they switch to a triggered state and a non-triggered state;

[0009] Based on the location information, the horizontal distance difference, and the vertical height difference, the first state information of the wafer is determined, and the first state information includes a forward and backward tilt state and a non-forward and backward tilt state.

[0010] According to the wafer state detection method of the present invention, the step of determining the first state information of the wafer based on the position information, the horizontal distance difference, and the vertical height difference includes:

[0011] Determine the first position information of the first through-beam sensor when it switches to a non-triggered state, and the second position information of the second through-beam sensor when it switches to a non-triggered state;

[0012] Based on the first position information, the second position information, the horizontal distance difference, and the vertical height difference, the front-to-back tilt rate of the wafer is calculated;

[0013] Based on the aforementioned tilt ratio, the first state information of the wafer is determined.

[0014] According to an embodiment of the wafer state detection method of the present invention, determining the first state information of the wafer based on the front and rear tilt rates includes:

[0015] The forward and backward tilt rates are compared with the preset tilt rate to obtain a first comparison result;

[0016] When the first comparison result is that the forward and backward tilt rate is greater than the preset tilt rate, it is determined that the wafer is in the forward and backward tilt state;

[0017] When the first comparison result is that the forward and backward tilt rate is less than or equal to the preset tilt rate, the wafer is determined to be in the non-forward and backward tilt state.

[0018] The wafer condition detection method according to an embodiment of the present invention further includes:

[0019] Determine the third position information of the first through-beam sensor when it switches to the trigger state, and the fourth position information of the second through-beam sensor when it switches to the trigger state;

[0020] Based on the first position information and the third position information, the first thickness information of the wafer is determined; based on the second position information and the fourth position information, the second thickness information of the wafer is determined.

[0021] Based on the first thickness information and the second thickness information, the second state information of the wafer is determined, and the second state information includes single-layer wafer, stacked wafer, skewed wafer, and abnormal wafer.

[0022] According to the wafer state detection method of the present invention, the step of determining the second state information of the wafer based on the first thickness information and the second thickness information includes:

[0023] The first thickness information is compared with the first preset thickness information, and the second thickness information is compared with the first preset thickness information to obtain a second comparison result;

[0024] When the second comparison result is that the first thickness information is less than the first preset thickness information and the second thickness information is less than the first preset thickness information, the wafer is determined to be a single-layer wafer.

[0025] The wafer condition detection method according to an embodiment of the present invention further includes:

[0026] If the second comparison result is that the first thickness information is less than the first preset thickness information and the second thickness information is greater than or equal to the first preset thickness information, or if the second comparison result is that the second thickness information is less than the first preset thickness information and the first thickness information is greater than or equal to the first preset thickness information, then the wafer is determined to be abnormal.

[0027] According to an embodiment of the wafer condition detection method of the present invention, when the second comparison result is that the first thickness information is greater than or equal to the first preset thickness information and the second thickness information is greater than or equal to the second preset thickness information, the method further includes:

[0028] The first thickness information is compared with the second preset thickness information, and the second thickness information is compared with the second preset thickness information to obtain a third comparison result;

[0029] When the third comparison result is that the first thickness information is less than the second preset thickness information and the second thickness information is less than the second preset thickness information, the wafer is determined to be a stacked wafer.

[0030] The wafer condition detection method according to an embodiment of the present invention further includes:

[0031] When the third comparison result is that the first thickness information is greater than or equal to the second preset thickness information and the second thickness information is greater than or equal to the second preset thickness information, the wafer is determined to be a skewed wafer.

[0032] The wafer condition detection method according to an embodiment of the present invention further includes:

[0033] When the third comparison result is that the first thickness information is less than the second preset thickness information and the second thickness information is greater than or equal to the second preset thickness information, or when the third comparison result is that the second thickness information is less than the second preset thickness information and the first thickness information is greater than or equal to the second preset thickness information, the wafer is determined to be abnormal.

[0034] According to a second aspect of the present invention, a wafer condition detection device includes a mounting frame on which a first through-beam sensor and a second through-beam sensor are disposed, and the first through-beam sensor and the second through-beam sensor have a horizontal distance difference and a vertical height difference.

[0035] A drive mechanism, disposed on the mounting bracket, drives the mounting bracket to move so that the first through-beam sensor and the second through-beam sensor scan the wafer;

[0036] A controller is used to control the drive mechanism to move the mounting bracket in order to perform the wafer state detection method described above.

[0037] The above-described one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects:

[0038] Embodiments of the present invention provide a wafer state detection method and a wafer state detection device. The wafer state detection method includes controlling a first pair of through-beam sensors and a second pair of through-beam sensors to scan the wafer. The first and second sensors are mounted on a mounting bracket, and there is a horizontal distance difference and a vertical height difference between them. The method determines the position information of the mounting bracket when the first and second through-beam sensors switch to a triggered state and a non-triggered state. Based on the position information, the horizontal distance difference, and the vertical height difference, the method determines first state information of the wafer, including a forward / backward tilt state and a non-forward / backward tilt state. By using two pairs of through-beam sensors with horizontal and vertical height differences to scan the wafer, and combining the position information of the first and second sensors when they switch to the triggered and non-triggered states, the forward / backward tilt degree of the wafer can be accurately calculated based on the horizontal distance difference and the vertical height difference, thereby determining the forward / backward tilt state of the wafer. Furthermore, the two pairs of through-beam sensors allow for cross-verification of their scanning data, improving the accuracy of wafer scanning and reducing the risk of wafer damage.

[0039] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1This is a schematic diagram of the wafer condition detection device provided in an embodiment of the present invention. Figure 1 ;

[0042] Figure 2 This is a schematic diagram of the wafer condition detection device provided in an embodiment of the present invention. Figure 2 ;

[0043] Figure 3 This is a flowchart illustrating the wafer state detection method provided in this embodiment of the invention. Figure 1 ;

[0044] Figure 4 This is a flowchart illustrating the wafer state detection method provided in this embodiment of the invention. Figure 2 ;

[0045] Figure 5 This is a flowchart illustrating the wafer state detection method provided in this embodiment of the invention. Figure 3 ;

[0046] Figure 6 This is a flowchart illustrating the wafer state detection method provided in this embodiment of the invention. Figure 4 .

[0047] Figure label:

[0048] 1. Mounting bracket; 2. Drive mechanism; 11. First through-beam sensor; 12. Second through-beam sensor; 13. Sensor bracket. Detailed Implementation

[0049] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0050] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0051] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0052] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0053] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0054] One embodiment of the present invention, in conjunction with Figures 1 to 2 As shown in the figure, an embodiment of the present invention provides a wafer state detection device, including a mounting frame 1, a driving mechanism 2, and a controller (not shown in the figure). The mounting frame 1 is provided with a first through-beam sensor 11 and a second through-beam sensor 12. There is a horizontal distance difference and a vertical height difference between the first through-beam sensor 11 and the second through-beam sensor 12. The driving mechanism 2 is disposed on the mounting frame 1 and can drive the mounting frame 1 to move so that the first through-beam sensor 11 and the second through-beam sensor 12 scan the wafer. The controller is used to control the driving mechanism 2 to drive the mounting frame 1 to move in order to perform wafer state detection.

[0055] It is understood that the mounting bracket 1 is provided with two pairs of sensor brackets 13. The first pair of beam sensors 11 and the second pair of beam sensors 12 both include a light-emitting part and a light-receiving part, which are mounted on the sensor brackets 13. The light-emitting part may include, but is not limited to, visible light LEDs, infrared LEDs, ultraviolet LEDs, fiber optic sensors, etc., and the light-receiving part may be a phototransistor, photodiode, infrared detection element, fiber optic, etc. The light-emitting part can emit light signals to the light-receiving part. In this embodiment, it is specified that when the light-receiving part receives the light signal emitted by the light-emitting part, the beam sensor is in a non-triggered state. When the light-receiving part does not receive the light signal emitted by the light-emitting part, that is, when there is obstruction between the light-receiving part and the light-emitting part, the beam sensor is in a non-triggered state. Based on the difference between the position information of the mounting bracket 1 when the first pair of beam sensors 11 and the second pair of beam sensors 12 are switched to the non-triggered state, combined with the difference in horizontal distance and vertical height between the two pairs of beam sensors, it can be determined whether the wafer is tilted forward or backward.

[0056] In one alternative implementation, such as Figure 2 As shown, the mounting bracket 1 and the sensor bracket 13 can be fixedly connected, for example, the mounting bracket 1 and the sensor bracket 13 can be fixedly connected by bolts or screws; in another optional embodiment, such as Figure 1 As shown, the sensor bracket 13 is rotatably connected to the mounting bracket 1, allowing adjustment of their relative positions. It is important to note that before wafer scanning and mapping, the sensor bracket 13 can be rotated to move the first through-beam sensor 11 and the second through-beam sensor 12 to the scanning and mapping position. Then, wafer scanning can begin. During wafer scanning and mapping, the relative positions of the sensor bracket 13 and the mounting bracket 1 are fixed, and the positions between the two pairs of sensor brackets 13 are also relatively fixed. In another optional embodiment, the relative positions of the sensor bracket 13 and the mounting bracket 1 are fixed. The mounting bracket 1 and the sensor bracket 1 are simultaneously moved to the wafer scanning and mapping position by the movement mechanism of the mounting bracket 1.

[0057] It is understood that the light-projecting and light-receiving parts of the first through-beam sensor 11 are respectively mounted on two different pairs of sensor brackets 13, and the light-projecting and light-receiving parts of the second through-beam sensor 12 are also respectively mounted on two different pairs of sensor brackets 13. Furthermore, the light-projecting part of the second through-beam sensor 12 and the light-receiving part of the first through-beam sensor 11 can be respectively mounted on the same sensor bracket 13, or the light-receiving part of the second through-beam sensor 12 and the light-projecting part of the first through-beam sensor 11 can be respectively mounted on another sensor bracket 13. This embodiment does not specifically limit this.

[0058] The drive mechanism 2 can drive the mounting bracket 1 to move up and down along the vertical direction, and scan and map the wafers arranged vertically in the wafer cassette in sequence. During the up and down movement of the mounting bracket 1, the position sensor provides real-time feedback on the position information of the mounting bracket 1. The data acquisition unit can collect the signals of the first through-beam sensor 11 and the second through-beam sensor 12 in real time. The data processing unit can obtain the position information of the mounting bracket 1 when the first through-beam sensor 11 and the second through-beam sensor 12 switch to the triggered state and the non-triggered state, and perform data processing.

[0059] According to one embodiment of the present invention, in order to improve the measurement accuracy of the device, the light-projecting parts of the first through-beam sensor 11 and the second through-beam sensor 12 can be blocked by a light-shielding plate with a slit to reduce the scattering of light emitted by the light-projecting parts and improve the measurement accuracy.

[0060] Another embodiment of the present invention, in conjunction with Figures 3-6 As shown, a wafer state detection method is provided, which may include:

[0061] S101, control the first and second through-beam sensors to scan the wafer; wherein the first and second sensors are mounted on the mounting bracket, and there is a horizontal distance difference and a vertical height difference between the first and second through-beam sensors;

[0062] In this embodiment, the mounting bracket can be moved up and down by a drive mechanism, so that the first and second through-beam sensors sequentially scan the wafers in the wafer cassette. It is understood that the first and second through-beam sensors are staggered in the horizontal and vertical directions, with horizontal and vertical height differences, and these differences are not zero. During the scanning process, there is a positional difference between the state switching of the first and second through-beam sensors.

[0063] S102, determine the position information of the first and second through-beam sensors when they switch to the triggered and non-triggered states;

[0064] It is understood that, in this embodiment, referring to the above definition, when the light receiving part receives the light signal emitted by the light projector, the through-beam sensor is in a non-triggered state; when the light receiving part does not receive the light signal emitted by the light projector, that is, when the light receiving part and the light projector are blocked, the through-beam sensor is in a non-triggered state.

[0065] The drive mechanism controls the mounting bracket to move from top to bottom or from bottom to top, sequentially scanning the wafers arranged in the wafer cassette and recording the position information of the first and second through-beam sensors when switching states.

[0066] In this embodiment, when calculating the reference position of the wafer, the position where the wafer contacts the slot (wafer carrier boss) in the wafer cassette can be used as the reference. When scanning from top to bottom, the position information fed back by the position sensor when the first sensor is switched to the non-trigger state can be used as the reference position of the first through-beam sensor corresponding to the wafer. When the second sensor is switched to the non-trigger state, the position information fed back by the position sensor can be used as the reference position of the second through-beam sensor corresponding to the wafer. The collected position information is compared with the theoretical wafer carrier boss position to determine the position of the wafer carrier boss of the currently scanned wafer.

[0067] S103, based on position information, horizontal distance difference and vertical height difference, determine the first state information of the wafer, the first state information includes forward and backward tilt state and non-forward and backward tilt state.

[0068] In this embodiment, the specific method for determining whether the wafer is in a forward or backward tilted state or not in a forward or backward tilted state may include:

[0069] Determine the first position information of the first through-beam sensor when it switches to the non-triggered state, and the second position information of the second through-beam sensor when it switches to the non-triggered state; calculate the front-to-back tilt rate of the wafer based on the first position information, the second position information, the horizontal distance difference, and the vertical height difference; determine the first state information of the wafer based on the front-to-back tilt rate.

[0070] Specifically, during wafer scanning, the third position information H1[i] of the first through-beam sensor is determined when the first through-beam sensor switches to the triggered state, and the second position information H2[i] is determined when the first through-beam sensor switches to the non-triggered state; the fourth position information h1[i] of the second through-beam sensor is determined when the second through-beam sensor switches to the triggered state, and the first position information h2[i] is determined when the second through-beam sensor switches to the non-triggered state. The formula for calculating the wafer's front-to-back tilt rate k is:

[0071] k=abs(abs(h2[i]-H2[i])-ΔH) / ΔL

[0072] Where abs is the absolute value of the result, ΔH is the vertical height difference, and ΔL is the horizontal distance difference. The front-to-back tilt rate of the wafer in the front-to-back direction is calculated according to the above formula.

[0073] According to an embodiment of the present invention, a method for determining the first state information of a wafer based on the front-to-back tilt ratio includes: comparing the front-to-back tilt ratio with a preset tilt ratio to obtain a first comparison result; when the first comparison result is that the front-to-back tilt ratio is greater than the preset tilt ratio, determining that the wafer is in a front-to-back tilt state; when the first comparison result is that the front-to-back tilt ratio is less than or equal to the preset tilt ratio, determining that the wafer is in a non-front-to-back tilt state.

[0074] It is understood that when the calculated front-to-back tilt rate k is greater than the preset tilt rate k, the wafer can be considered to be front-to-back tilted. The preset tilt rate k can be any real number between 0.0005 and 1, preferably between 0.001 and 0.2. In this embodiment, in addition to determining whether the wafer is front-to-back tilted, the degree of front-to-back tilt can also be determined. The larger the value of the preset tilt rate k, the more tilted the wafer is, making it easier to accurately determine the degree of tilt of the wafer in the front-to-back direction.

[0075] In one alternative implementation, such as Figure 4 As shown, i represents the i-th layer of wafers arranged sequentially in the wafer box. First, the second position information H2[i] of the first through-beam sensor when it is switched to non-triggering state is compared with the position of the wafer support boss to determine the current layer number of the wafer, that is, the current position of the wafer in the wafer box. Then, the wafer tilt rate is calculated according to the above method and it is determined whether the wafer is in a forward or backward tilt state or not. The calculation and judgment are performed on each layer of wafers in turn.

[0076] The wafer state detection method of this invention includes controlling a first pair of through-beam sensors and a second pair of through-beam sensors to scan the wafer. The first and second sensors are mounted on a mounting bracket, and there is a horizontal distance difference and a vertical height difference between them. The method determines the position information of the mounting bracket when the first and second through-beam sensors switch to a triggered state and a non-triggered state. Based on the position information, the horizontal distance difference, and the vertical height difference, the method determines first state information of the wafer, including a tilted state and a non-tilted state. By using two pairs of through-beam sensors with horizontal and vertical height differences to scan the wafer, and combining the position information of the first and second sensors when they switch to the triggered and non-triggered states, the tilted degree of the wafer can be accurately calculated based on the horizontal distance difference and the vertical height difference, thereby determining the tilted state of the wafer. Furthermore, the two pairs of through-beam sensors allow for cross-verification of their scanning data, improving the accuracy of wafer scanning and reducing the risk of wafer damage.

[0077] According to one embodiment of the present invention, such as Figure 5 As shown, the wafer condition detection method also includes:

[0078] S201, determine the third position information of the first through-beam sensor when it switches to the trigger state, and the fourth position information of the second through-beam sensor when it switches to the trigger state;

[0079] S202, determine the first thickness information of the wafer based on the first position information and the third position information; determine the second thickness information of the wafer based on the second position information and the fourth position information;

[0080] S203, based on the first thickness information and the second thickness information, determine the second state information of the wafer, which includes single-layer wafer, stacked wafer, skewed wafer, and abnormal wafer.

[0081] According to one embodiment of the present invention, determining the second state information of a wafer based on first thickness information and second thickness information includes: comparing the first thickness information with first preset thickness information, and comparing the second thickness information with the first preset thickness information to obtain a second comparison result; when the second comparison result is that the first thickness information is less than the first preset thickness information and the second thickness information is less than the first preset thickness information, the wafer is determined to be a single-layer wafer. It is understood that when both the first thickness information and the second thickness information are less than the first preset thickness information, the measurement results of the first and second through-beam sensors are the same, and the wafer can be considered to be a single-layer wafer, i.e., the wafer is composed of a single-layer wafer.

[0082] According to one embodiment of the present invention, if the second comparison result is that the first thickness information is less than the first preset thickness information and the second thickness information is greater than or equal to the first preset thickness information, or if the second comparison result is that the second thickness information is less than the first preset thickness information and the first thickness information is greater than or equal to the first preset thickness information, a wafer anomaly is determined. It is understood that when the measurement results of the first and second through-beam sensors differ, it may be due to measurement or operational errors. In this case, the wafer measurement can be considered abnormal, and an alarm can be triggered to remind the user to pay close attention to the wafer's status or to re-measure the wafer. This embodiment does not impose specific limitations.

[0083] According to an embodiment of the present invention, when the second comparison result is that the first thickness information is greater than or equal to the first preset thickness information and the second thickness information is greater than or equal to the second preset thickness information, the wafer state detection method further includes: comparing the first thickness information with the second preset thickness information, and comparing the second thickness information with the second preset thickness information to obtain a third comparison result; when the third comparison result is that the first thickness information is less than the second preset thickness information and the second thickness information is less than the second preset thickness information, the wafer is determined to be a stacked wafer.

[0084] It is understandable that when both the first thickness information and the second thickness information are greater than or equal to the first preset thickness information, the wafer may be composed of a double-layer wafer. In this case, the first thickness information and the second thickness information can be compared with the second preset thickness information. If the comparison result shows that both the first thickness information and the second thickness information are less than the second preset thickness information, the wafer can be considered to be composed of a double-layer wafer, and the wafer is determined to be a stacked wafer.

[0085] According to one embodiment of the present invention, the wafer state detection method further includes: when the third comparison result is that the first thickness information is greater than or equal to the second preset thickness information and the second thickness information is greater than or equal to the second preset thickness information, the wafer is determined to be a skewed wafer. It can be understood that when the measurement results of the first through-beam sensor and the second through-beam sensor are the same and both indicate that the first thickness information and the second thickness information are greater than or equal to the second preset thickness information, the wafer can be considered to be tilted left or right, and at this time the wafer is determined to be a skewed wafer (tilted left or right).

[0086] According to an embodiment of the present invention, the wafer state detection method further includes: determining a wafer anomaly when the third comparison result is that the first thickness information is less than the second preset thickness information and the second thickness information is greater than or equal to the second preset thickness information, or when the third comparison result is that the second thickness information is less than the second preset thickness information and the first thickness information is greater than or equal to the second preset thickness information. It is understood that when the measurement results of the first and second through-beam sensors are different, i.e., one of the first and second thickness information is greater than or equal to the second preset thickness information and the other is less than the second preset thickness information, it indicates that there is an anomaly in the detection of the wafer. In this case, an alarm can also be used to alert the user that the measurement result of the wafer is abnormal.

[0087] In this embodiment, the wafer is scanned by setting a first pair of photoelectric sensors and a second pair of photoelectric sensors. The measurement results of the two pairs of photoelectric sensors are mutually verified to ensure the consistency of the measurement results, which improves the accuracy of wafer scanning and reduces the risk of wafer damage.

[0088] In another alternative real-time method, combined with Figure 6 As shown, i represents the i-th layer of wafers arranged sequentially in the wafer cassette. The first thickness information H'[i] scanned by the first through-beam sensor is H1[i] - H2[i], and the second thickness information h'[i] scanned by the second through-beam sensor is h1[i] - h2[i]. After calculating the first thickness information H'[i] and the second thickness information h'[i] of the wafer, the first thickness information H'[i] and the second thickness information h'[i] are compared with the theoretical thickness H of the wafer. W By comparison, we obtain M[i] = H'[i] - H W m[i] = h'[i] - HW M[i] and m[i] are compared with the first standard value (Spec1) of the standard wafer. If the value of M[i] is less than Spec1 of the standard wafer, the wafer layer is considered to be a single-layer wafer. If the value of M[i] is greater than Spec1 of the standard wafer and less than the second standard value (Spec2) of the double wafer, the wafer layer is considered to be a double wafer. If the value of M[i] is greater than Spec2 of the double wafer, the wafer layer is considered to be a skewed wafer (tilted left and right). Similarly, the wafer thickness scanned by the second through-beam sensor is used for thickness verification. If the comparison results of M[i] and m[i] are inconsistent, an alarm for different measurement results is triggered.

[0089] Embodiments of the present invention provide a wafer state detection method and a wafer state detection device. The wafer state detection method includes controlling a first pair of through-beam sensors and a second pair of through-beam sensors to scan the wafer. The first and second sensors are mounted on a mounting bracket, and there is a horizontal distance difference and a vertical height difference between them. The method determines the position information of the mounting bracket when the first and second through-beam sensors switch to a triggered state and a non-triggered state. Based on the position information, the horizontal distance difference, and the vertical height difference, the method determines first state information of the wafer, including a forward / backward tilt state and a non-forward / backward tilt state. By using two pairs of through-beam sensors with horizontal and vertical height differences to scan the wafer, and combining the position information of the first and second sensors when they switch to the triggered and non-triggered states, the forward / backward tilt degree of the wafer can be accurately calculated based on the horizontal distance difference and the vertical height difference, thereby determining the forward / backward tilt state of the wafer. Furthermore, the two pairs of through-beam sensors allow for cross-verification of their scanning data, improving the accuracy of wafer scanning and reducing the risk of wafer damage.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of this application.

Claims

1. A method for detecting the state of a wafer, characterized in that, include: The first and second through-beam sensors are controlled to scan the wafer; wherein the first and second through-beam sensors are mounted on a mounting bracket, and there is a horizontal distance difference and a vertical height difference between the first and second through-beam sensors; Determine the position information of the first and second through-beam sensors when they switch to a triggered state and a non-triggered state; Based on the location information, the horizontal distance difference, and the vertical height difference, the first state information of the wafer is determined, and the first state information includes a forward and backward tilt state and a non-forward and backward tilt state. Determining the first state information of the wafer based on the position information, the horizontal distance difference, and the vertical height difference includes: Determine the first position information of the first through-beam sensor when it switches to a non-triggered state, and the second position information of the second through-beam sensor when it switches to a non-triggered state; Based on the first position information, the second position information, the horizontal distance difference, and the vertical height difference, the front-to-back tilt rate of the wafer is calculated; Based on the aforementioned tilt ratio, the first state information of the wafer is determined; Determine the third position information of the first through-beam sensor when it switches to the trigger state, and the fourth position information of the second through-beam sensor when it switches to the trigger state; Based on the first position information and the third position information, the first thickness information of the wafer is determined; based on the second position information and the fourth position information, the second thickness information of the wafer is determined. Based on the first thickness information and the second thickness information, the second state information of the wafer is determined, and the second state information includes single-layer wafer, stacked wafer, skewed wafer, and abnormal wafer.

2. The wafer condition detection method according to claim 1, characterized in that, Determining the first state information of the wafer based on the tilt ratio includes: The forward and backward tilt rates are compared with the preset tilt rate to obtain a first comparison result; When the first comparison result is that the forward and backward tilt rate is greater than the preset tilt rate, it is determined that the wafer is in the forward and backward tilt state; When the first comparison result is that the forward and backward tilt rate is less than or equal to the preset tilt rate, the wafer is determined to be in the non-forward and backward tilt state.

3. The wafer condition detection method according to claim 1, characterized in that, Determining the second state information of the wafer based on the first thickness information and the second thickness information includes: The first thickness information is compared with the first preset thickness information, and the second thickness information is compared with the first preset thickness information to obtain a second comparison result; When the second comparison result is that the first thickness information is less than the first preset thickness information and the second thickness information is less than the first preset thickness information, the wafer is determined to be a single-layer wafer.

4. The wafer condition detection method according to claim 3, characterized in that, The method further includes: If the second comparison result is that the first thickness information is less than the first preset thickness information and the second thickness information is greater than or equal to the first preset thickness information, or if the second comparison result is that the second thickness information is less than the first preset thickness information and the first thickness information is greater than or equal to the first preset thickness information, then the wafer is determined to be abnormal.

5. The wafer condition detection method according to claim 3, characterized in that, If the second comparison result is that the first thickness information is greater than or equal to the first preset thickness information and the second thickness information is greater than or equal to the first preset thickness information, the method further includes: The first thickness information is compared with the second preset thickness information, and the second thickness information is compared with the second preset thickness information to obtain a third comparison result; When the third comparison result is that the first thickness information is less than the second preset thickness information and the second thickness information is less than the second preset thickness information, the wafer is determined to be a stacked wafer.

6. The wafer condition detection method according to claim 5, characterized in that, The method further includes: When the third comparison result is that the first thickness information is greater than or equal to the second preset thickness information and the second thickness information is greater than or equal to the second preset thickness information, the wafer is determined to be a skewed wafer.

7. The wafer condition detection method according to claim 5, characterized in that, The method further includes: When the third comparison result is that the first thickness information is less than the second preset thickness information and the second thickness information is greater than or equal to the second preset thickness information, or when the third comparison result is that the second thickness information is less than the second preset thickness information and the first thickness information is greater than or equal to the second preset thickness information, the wafer is determined to be abnormal.

8. A wafer condition detection device, characterized in that, include: Mounting frame, on which a first through-beam sensor and a second through-beam sensor are provided, and there is a horizontal distance difference and a vertical height difference between the first through-beam sensor and the second through-beam sensor; A drive mechanism, disposed on the mounting bracket, drives the mounting bracket to move so that the first through-beam sensor and the second through-beam sensor scan the wafer; A controller is used to control the drive mechanism to drive the mounting bracket to move in order to perform the wafer state detection method according to any one of claims 1-7.

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